HomeMy WebLinkAboutAPA129 Exh E Chp 3 Feb 1983~fN~ijB:,.tDROea:..cmtc PROJE~:UGENgE APPLI'c~TION
~PROJECT NO.7114..QOO
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BEFORE THE
FEDERAL ENERGY REGULATORY COMMISSION
APPLICATION FOR LICE NSE FOR MAJOR PROJ ECT
SUSITNA .HYDROELECTRIC PROJECT
VOLUME 6A
EXHIBIT E
Chapter 3
FEBRUARY 1983
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I.--__ALASKA POWER AUTHORITY __---"
SUSITNA HYDROELECTRIC PROJECT
VOLUME 6A
EXHI BIT E CHAPTER 3
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FISH,WILDLIFE AND BOTANICAL RESOURCES
TABLE OF CONTENTS
1 -INTRODUCTION E-3-1
1.1 -Baseline Description E-3-1
1.2 -Impact Assessments E-3-1
1.3 -Mitigation Plans E-3-3
2 -FISH RESOURCES OF THE SUSITNA RIVER DRAINAGE E-3-7
2.1 -Overvi ew of the Resources ...........•..............E-3-7
2.1.1 -Description of the Study Area for
Fi sh Resources E-3-7
2.1.2 -Data Collection and Analysis Methods E-3-7
2.1.3 -Threatened and Endangered Species E-3-11
2.1.4 -Overview of Important Species E-3-11
2.1.5 -Contribution of Commercial and
Non-Commercial Fishery E-3-11
2.2 -Species Biology and Habitat Utilization in the
Susitna Drainage E-3-15
2.2.1 -Species Biology E-3-15
2.2.2 -Habitat Utilization E-3-46
2.2.3 -Streams of Access Road Corridor E-3-68
2.2.4 -Streams of the Transmission E-3-70
2.3 -Anticipated Impacts to Aquatic Habitat E-3-71
2.3.1 -Anticipated Impacts to Aquatic Habitat
Associ ated with Watana Dam E-3-72
2.3.2 -Anticipated Impacts to Aquatic Habitat
Associated with Devil Canyon E-3-124
2.3.3 -Impacts Associated with Access Roads,
Site Roads and Railrods E-3-124
2.3.4 -Impacts Associated with Access Roads,
Site Roads and Rai lroads E-3-124
2.4 -Mitigation Issues and Mitigation Measures E-3-141
2.4.1 -Approach to Mitigation E-3-141
2.4.2 -Selection of Project Evaluation Species E-3-147
2.4.3 -Mitigation of Construction Impacts Upon
Fish and Aquatic Habitats E-3-150
2.4.4 -Mitigation of Filling and Operation
Impacts E-3-160
2.4.5 -Cumulative Effectiveness of Mitigation E-3-175
TABLE OF CONTENTS
Page
2.5 -Aquatic Studies Program E-3-179
2.5.1 -Preconstruction Phase ,E-3-179
2.5.2 -Construction Phase E-3-179
2.5.3 -Filling and Operation Phase E-3-180
2.6 -Monitoring Studies E-3-180
2.6.1 -Construction Monitoring E-3-180
2.6.2 -Operational Monitoring ..'"E-3-182
2.7 -Cost of Mitigation ":'"E-3-185
2.8 -Agency Consultation on Fisheries Mitigation
Measures E-3-186
2.8.1 -U.S.Fish and Wildlife Service E-3-189
2.8.2 -Alaska Department of Fish and Game E-3-190
3 -BOTANICAL RESOURCES E-3-191
3.1 -Introduct ion E-3-191
3.1.1 -Regional Botanical Setting E-3-192
3.1.2 -Floristics E-3-193
3.1.3 -Coostribution to Wildlife,Recreation,
Subs i stance,and Commerce E-3-195
3.2 -Baseline Description E-3-196
3.2.1 -Threatened or Endangered Plants E-3-196
3.2.2 -Plant Communities E-3-198
3.2.3 -Wetlands E-3-220
3.3 -Impacts E-3-224
3.3.1 -Watana Development E-3-225
3.3.2 -Devil Canyon Development E-3-240
3.3.3 -Access E-3-243
3.3.4 -Transmission Corridors E-3-244
3.3.5 -Impacts to Wetlands E-3-245
3.3.6 ~Prioritization of Impact Issues E-3-246
3.4 -Mitigation Plan E-3-250
3.4.1 -Introduction E-3-250
3.4.2 -Option Analysis E-3-252
3.4.3 -Mitigation Summary E-3-291
4 -WILDL IFE E-3-294
4.1 -Introduction E-3-294
4.1.1 -The Vertebrate Fauna E-3-294
4.1.2 -Threatened or Endangered Species E-3-295
4.1.3 -Species Contributing to Recreation,
Subsistence,and Commerce £-3-295
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TABLE OF CONTENTS
4.2 -Baseline ~escription .
4.2.1 -B'i g Game .
4.2.2 -~urbearers .
4.2.3 -Bir'ds .
4.2.4 -~on-Game (Small)Mammals .
4.3 -Impacts .
4.3.1 -Watana Development .
4.3.2 -Devil Canyon Development .
4.3.3 -Access Roads and Railway .
4.3.4 -Transmission Lines .
4.3.5 -Impact Summary .
/4.4 -Mitigation Plan .
{//4.4.1 -Impact Issues and Option Analysis ,.
4.4.2 -Mitigation Plans and Monitoring
Invest i gat ions ...................•.........
4.4.3 -Cost Analysis and Schedules .
4.4.4 -Documentation of Agency Recommendations
REFERENCES
E-3-296
E-3-296
E-3-354
E-3-366
E-3-388
E-3-396
E-3-396
E-3-462
E-3-476
E-3-492
E-3-499
E-3-508
E-3-508
E-3-523
E-3-544
E-3-546
-Introduction E-3-551
-Fi sheri es E-3-552
-Wildlife and Botanical Resources E-3-566
LIST OF TABLES
LIST OF FIGURES
i
xvi
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Appendix E3A -Fish and Wildlife Mitigation Policy
Appendix E3B -Environmental Guidelines Memorandum
Appendix E3C -Preliminary List of Plant Species Upper and
Middle Susitna River
Appendix E3D -Preliminary list of Plant Species Intertie Area
Appendix E3E -Status,Habitat Use and Relative Abundance
of Bird Species in the Middle Susitna Basin
Appendix E3F -Status of Relative Abundance of Bird Species
in the Lower Susitna Basin
Appendix E3G -Scientific Names of Mammal Species
Appendix E3H -Methods Used to Determine ~bose Browse Utili-
zation and Carrying Capacity within the Middle
Sus itna Bas in
Appendix E3I -Explanation and Justification of Artifical
Nest Mitigation
Appendix E3J -Personal Communications
GLOSSARY
LIST OF TABLES
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E.3.1
E.3.2
E.3.3
E.3.4
E.3.5
E.3.6
E.3.7
E.3.8
E.3.9
Mitigation Options Analysis Structure
Recommended by Susitna Hydroel ectri c Project,
Alaska Department of Fish and Game and
the u.S.Fish and Wildlife Service
Common and Scientific Names of Fish Species
Recorded from the Susitna Basin
Commercial Catch of Upper Cook Inlet
Salmon in Numbers of Fish by Species,
1954-1982
Commercial Catch of Lower Cook Inlet
Salmon in Number of Fish By Species,
1954-1982
Side-Scan Sonar Counts of Salmon Migrating
Past Yentna Station,and Peterson Population
Estimates and Corresponding 95%Confidence
Intervals of Salmon Migrating to Sunshine,
Talkeetna and Curry Stations,1981-1982
Susitna Basin Sport Fish Harvest and Effort by
Fishery and Species -1978,1979, 1980,1981
Chinook Salmon Escapement Counts of Susitna
River Basin Streams from 1976 to 1982,Adult
Anadromous Investigations,Susitna Hydro
Studies,1982
1982 Chinook Salmon Escapement Surveys of
Susitna River Basin Streams Adult Anadromous
Investigations,Susitna KYdro Studies,1982
Preliminary Results of 1982 Smolt Trap
Catches at Talkeetna Station
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E.3.10 Adult Salmon Migration Rates
(in miles per day)
E.3.11 Analysis of Sockeye Salmon Age Data by Percent
From Escapement Samples Collected at Susitna,
Yentna,Sunshine,Talkeetna and Curry Stations,
Adult Anadromous Investigations,Susitna Hydro
Studies,1981
E.3.12 Estimated Number of Slough Spawning Sockeye,
Chum and Pink Salmon in Sloughs Between Devil
Canyon and Talkeetna,1981 to 1982
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LIST OF TABLES
E.3.13 Mainstem Susitna River Salmon Spawning
Locations Identified in 1981-1982
E.3.14 Coho Salmon Juveniles,Percent Incident at
Habitat Location Sites on the Mainstem Susitna
River and Its Tributary Mouths Between Cook
Inlet and Devil Canyon -November 1980 to May 1981
E.3.15 Coho Salmon Juveniles,Percent Incident at
Habitat Location Sites on the Mainstem Susitna
River and Its Tributary Mouths Between Cook
Inlet and Talkeetna -June to September 1981
E.3.16 Arctic Grayling Hook and Line Total Catch
by Tributary Between the Mouth and Proposed
Impoundment Elevations (PIE)and Mouth in
the Impoundment Study Area -1981
E.3.17 Arctic Grayling Population Estimates for
the Reach of Major Tributaries in the Watana
and Devil Canyon Impoundment Areas
E.3.18 Peterson Population Estimate for Arctic Grayling
by Age Group in the Watana Impoundment,Area,
Summer 1982
E.3.19 Streams Crossed by Denali Highway
(Cantwell to Watana Access Junction)
E.3.20 Streams to be Crossed by Watana Access
Road (Denali Highway to Watana Dam)
E.3.21 Streams to be Crossed by Devil Canyon
Access Road and Transmission Line Between
Watana and Devil Canyon,and Railroad
Spur from Gold Creek to Devil Canyon
E.3.22 Waterbodies to be Crossed by the Susitna
Transmission Line (Anchorage to Willow)
E.3.23 Waterbodies to be Crossed by the Susitna
Transmission Line (Healy to Fairbanks)
E.3.24,Effects of Su rfac i ng and Ea rthwork on
Physical and Chemical Characteristics of
Aquatic Habitat
E.3.25 Increase in Water Surface Elevation
During Initial Fill of Watana Reservoi r
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LIST OF TABLES
E.3.26 Comparison of Average Monthly Streamflows
at Gold Creek During Initial Filling of
Watana Reservoir
E.3.27 Major Impact Issues During Filling of
Watana Reservoir Regarding Salmonids in
the Talkeetna-to-Devil Canyon Reach
E.3.28 Major Tributaries to be Inundated
E.3.29 Comparison of Average Monthly Streamflows
at Sunshine During Initial Filling of
Watana Reservoir
E.3.30 Comparison of Average Monthly Streamflows
at Susitna Station During Initial Filling
of Watana Reservoir
E.3.31 Major Impact Issues During Operation of
Watana Reservoi r Regardi ng Salmonids in
the Talkeetna-to-Devil Canyon Reach
E.3.32 Comparison of Average Monthly Streamflows
at Gold Creek Station Under Operation of
Watana Dam
E.3.33 Comparison of Average Monthly Streamflows
at Sunshine Station Under Operation of
Watana Dam
E.3.34 Comparison of Average Monthly Streamflows
at Susitna Station Under Operation of
Watana Dam
E.3.35 Comparison of Average Monthly Streamflows
at Gold Creek of the Two Operational Watana
and Devil Canyon Dams
E.3.36 Comparison of Average Monthly Streamflows at
Sunshine of the Two Operational Watana and
Devil Canyon Dams
E.3.37 Comparison of Average Monthly Streamflows
at Susitna of the Two Operational Watana
and Devil Canyon Dams
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LIST OF TABLES
E.3.38 Impact Issues and Proposed Mitigation
Features for Anticipated Filling and
Operational Impacts to Aquatic Habitats
Susitna Hydroelectric Project
£.3.39 Proposed Fisheries Mitigations with Estimated
Capital and Annual Operating and Maintenance
Costs
E.3.40 Schedule for Implementing Fisheries
Mitigation Program
E.3.41 Construction Costs for Water Quality
and Fisheries Monitoring in 1982 Dollars
from 1985 to 2002
E.3.42 Alaska Department of Fish and Game Standards
for Passing Arctic Grayling to be Used on
Susitna Hydroelectric Project Stream Crossings
E.3.43 Alaska Department of Fish and Game Temporary
Stream Diversion Standards
E.3.44 Alaska Department of Fish and Game Standards
for Blasting Near an Anadromous Fish Stream
E.3.45 Cost Assumptions Used in Developing Estimated
Costs for Fisheries Mitigation
E.3.46 Estimated Square Feet of Salmon Spawning
Habitat Made Available by Mitigation
Procedures
E.3.47 Annual Operating Costs of Fisheries
Monitoring Program in 1982 Dollars
E.3.48 Vascular Plant Species in the Watana
and Gold Creek Watersheds and Downstream
Floodplain Which Are Outside Their Range
E.3.49 Candidate Endangered and Threatened Plant
Taxa Sought in the Watana and Gold Creek
Watershed Surveys with Notes on Thei r
Habitats and Known Localities
E.3.50 Vegetation Types (and sample location numbers)
Sampled in Watana and Gold Creek Watersheds
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LIST OF TABLES
E.3.51 Hectares and Percentage of Total Area Covered
by Vegetation Types in the Watana and Gold Creek
Watersheds
E.3.52 Hectares and Percentage of Total Area
Covered by Vegetation Types for the Area
16 km on Either Side of the Susitna River
From Gold Creek to the Maclaren River
E.3.53 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Open Conifer Vegetation Type in Watana
and Gold Creek Watersheds
E.3.54 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in Open
White Spruce Vegetation Type in Watana
and Gold Creek Watersheds
E.3.55 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Open Bl ack Sp ruceVegetat i on Type in
Watana and Gold Creek Watersheds
E.3.56 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Woodland Conifer Vegetation Typei n Watana
and Gold Creek Watersheds
E.3.57 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in .
Closed Balsam Poplar Forest Vegetation
Type in Watana and Gold Creek Watersheds
E.3.58 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Closed Birch Deciduous Forest Vegetation
Type in Watana and Gold Creek Watersheds
E.3.59 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Closed Aspen Deciduous Vegetation Type
in Watana and Gold Creek Watersheds
E.3.60 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in Open
Mixed Conifer-Deciduous Forest Vegetation
Type in Watana and Gol d Creek Watersheds
v
LIST OF TABLES
E.3.61 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Closed Mixed Conifer-Deciduous Forest
Vegetation Type in Watana and Gold Creek
E.3.62 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in Wet
Sedge-Grass Tundra Vegetation Type in
Watana and Gold Creek Watersheds
E.3.63 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Mesic Sedge-Grass Tundra Vegetation
Type in Watana and Gold Creek Watersheds
E.3.64 Plant Species List of One Herbaceous
Alpine Tundra Stand in Watana and Gold
Creek Watersheds
E.3.65 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Closed Mat and Cushion Tundra Vegetation
Type in Watana and Gold Creek Watersheds
E.3.66 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Closed Tall Alder Vegetation Type in
Watana and Gold Creek Watersheds
E.3.67 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Open Tall Alder Vegetation Type in Watana
and Gold Creek Watersheds
E.3.68 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in
Closed Low Shrub Vegetation Type in
Watana and Gold Creek Watersheds
E.3.69 Cover Percentages for Total Vegetation,
Vertical Strata,and Plant Species in Open
Low Shrub Vegetation Type in Watana and
Gold Creek Watersheds
E.3.70 Aquatic Plant Survey,Susitna Hydroelectric
Project,August 1980
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LIST OF TABLES
Eo 3.71 Hectares and Percentage of Total Area Covered
by Vegetative Community Types in the Watana
Watershed
E.3.72 Hectares and Perc€ntage of Total Area
Covered by Vegetative Community Types
in the Gold Creek Watershed
E.3.73 Percent Cover in Early Successional Stands
on Downstream Foodpl~in of Susitna River
E.3.74 Percent Cover in Alder Stands on Downstream
Floodplain of Susitna River
E.3.75 Percent Cover in Immature Balsam Poplar Stands
on Downstream Floodplain
E.3.76 Percent Cover in Bi rch-Spruce Stands on
Downstream Floodplain,Summer 1981
E.3.77 Hectares and Percent of Total Area Covered By
Vegetation Types Within the Healy To Fai rbanks
Study Corridor
E.3.78 Hectares and Percent of Total Area Covered by
Vegetation Types Within the Willow To Cook Inlet
Study Corridor
E.3.79 Areas of Different Vegetation Types To Be Crossed
by Willow-To-Healy Transmission Corridor
E.3.80 Areas of Each Vegetation Type to Be Crossed by
Watana-To-Gold Creek Transmission Corridors and
Percent Total for Watana and Gold Creek Watersheds
E.3.81 Vegetation and Wetland Class~s Found in the Proposed
Susitna Impoundment and Borrow Areas
£.3.82 Hectares of Different Wetland Types by Project
Component
E.3.83 Hectares of Gifferent Vegetation Types to be
Affected by theWatana Facil ity Compared with
Total Hectares of That Type Upstream of Gold
Creek in the Susitna Watershed and in the Area
Within 16 km of the Susitna River
vii
LIST OF TABLES
E.3.84 Hectares of Different Vegetation Types to be
Affected by the Devil Canyon Facility Compared
Wi th Total Hecta res of That Type in the Watana
and Gold Creek Watersheds and in the Area Within
16 km of the Susitna River
E.3.85 Areas of Each Vegetation Type to be Cleared for
Access and Percent Total for Watana and Gold
Creek Watersheds
E.3.86 Areas of Different Vegetation Types to be
Crossed by Transmission Corridors
E.3.87 Comparison Between Aerial Habitat Classifications and
Those of Viereck and'Dyrness (1980)Used to Classify
Observations of Radio-Collared Moose in the Nelchina
and Susitna River Basins of South-Central Alaska from
1977 Through Mid-August
E.3.88 Monthly Use of Habitat Types by Radio-Collared Moose
of Both Sexes and All Ages as Determined From Fixed-Wing
Aircraft from October 1976 Through Mid-August 1981 in
the Middle and Upper Susitna and Nelchina River Basins
E.3.89 Summary of Elevational Use by Approximately 200 Radio
Collared Moose (Both Sexes and All Age Classes)From
October 1976 Through Mid-August 1981 in the Middle and
Upper Susitna and Nelchina River
E.3.90 Occurrence and Mean Percent of Canopy Coverage for Species
of Ri pa ri an and Non-Ri pa ri an Vegetat i on and Habi tat Types
Observed at Relocation Sites for 6 Male Moose Captured and
Radio-Collared Along the Susitna River South of Talkeetna,
Alaska,and Monitored During Calving,Summer,Breeding,
and Transitional Periods from March 16 to October 15,1981
E.3.91 Occurrence and Mean Percent of Canopy Coverage for Species
of Riparian and Non-Riparian Vegetation and Habitat Types
Observed at Relocation Sites for 19 Female Moose Captured
and Radio-Collared Along the Susitna River South of
Talkeetna,Alaska,and Monitored During Calving,Summer,
Breeding,and Transitional Periods from March 16 to
October 15,1981
E.3.92 Winter Carrying Capacity of the Watana Impoundment Zone
(Including Adjacent Project Facilities)and Susitna
Watershed Upstream of Gold Creek for Moose Based on the
Biomass of Twigs Available in Winter
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LIST OF TABLES
E.3.93 Dates Indicating Chronology of Departure From
Susitna River Wintering Areas for Male and Female
Moose Radio-Collared on the Susitna River Downstream
From Talkeetna,March 10-12,1981
E.3.94 Minimum,Maximum and Mean Distance to the Susitna
River from Geometrical Centers of the Calving
Range,Summer Range,and Breeding Range for Male and
Female Moose Radio-Collared in Several Locations
Along the Susitna River Between Devil Canyon and
the Delta Islands,Alaska 1980-81
E.3.95 Proximity to the Susitna River of Relocations of
9 Mal e and 29 Femal e Moose Radi o-Coll ared Along The
Susitna River Between Devil Canyon and the Delta
Islands,Alaska,1980-81
E.3.96 Summary of Moose Sex and Age Composition Data
Collected Annually in Count Area 6 in Game
Management Unit 13 of Southcentral Alaska
E.3.97 Summary of Moose Sex and Age Composition Data
Collected Annually in Count Area 7 in Game
Management Unit 13 of Southcentral Alaska
E.3.98 Summary of Moose Sex and Age Composition Data
Collected Annually in Count Area 14 in Game
Management Unit 13 of Southcentral Alaska
E.3.99 Summary of Moose Census Data and Subsequent Population
Estimates for Count Areas 7 and 14 Derived from
Surveys Conducted Along the Susitna River From
November 5 through November 8,1980
E.3.100 Density (Moose/km of River)Of Moose Observed on 10
Aerial Censuses in 4 Zones of Riparian Habitat Along
the Susitna River from Devil Canyon to Cook Inlet,
Alaska,1981-82
E.3.101 Summary of Moose Sex and Age Composition Data
Obtained During Surveys of Riparian Communities
Along the Lower Susitna River
E.3.102 Proportion of Radio-Collared Caribou Sightings
In Each Vegetation Type
ix
LIST OF TABLES
E.3.103 Nelchina Caribou Herd Population Estimates
E.3.104 Reported Hunter Harvest of the Nelchina
Caribou Herd,1972-1981
E.3.105 Compilation of Highest Yearly Counts
Completed in Watana Hills Sheep Trend
Count Area
E.3.106 Number and Age-Sex Classification of Sheep
Observed at Jay Creek Mineral Licks From
May 6 Th rough June 24,1981
E.3.107 Number of Aerial Brown Bear Observations By
Month in Each of 5 Maj or Habitat Categori es
E.3.108 Comparison of Reported Home Range Sizes of
Brown/Grizzly Bears in North America
E.3.109 Densities of Selected North American Brown
Bear Popul ations
L3.110 Averge Age and Sex Rati os of Brown Bear
Populations in the Middle and Upper Susitna
and Nelchina River Basins
E.3.111 Litter Sizes of Various North American
Brown Bear Populations
E.3.112 Reproductive Rates of North American Brown
Bear Populations
E.3.113 Summary of Brown Bear Harvest from Alaska1s
Game Management Unit 13,1973-1980
E.3.114 Nmber of Aerial Black Bear Observations by Month
in Each of 5 Habitat Categories
E.3.115 Summary of Reported Black Bear Harvests From
Alaska's Game Management Unit 13,1973-1980
E.3.116 Comparisons of Food Remains in Wolf Scats Collected
At Den and Rendezvous Sites in 1980 and 1981 from
the Eastern Susitna Basin and Adjacent Areas
E.3.117 Estimate of Numbers of W,olves by Individual Pack
Inhabit ing the Susitna Hydroel ectri c Study Area in
Spring and Fall 1980 and 1981
x
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LIST OF TABLES
E.3.118 Number of sample Units Containing Indicated
Level of Beaver Activity During Summer 1982
Downstream Survey
£.3.119 1982 Aerial Counts of Beaver Structures Along
15.2 Km (9.4 Mi)of Lower Deadman Creek Immediately
Downstream from Deadman Lake,and A Marshy Section
of Upper Deadman Creek From Its Mouth at Deadman
lake 3.2 Km (2.0Mi)Upstream From The Lake
E.3.120 Results of Surv~ys For Muskrat Pushups Upstream
From Gold Creek During Spring 1980
E.3.121 Numbers of Furbearer Tracks Seen Duri ng Aeri a 1
Transects in the Middle Susitna Basin,November 1980
E.3.122 Tabulation of November 1980 Aerial Transect Data,
Species by Vegetation Type
E.3.123 Number of Tracks of Otter and M,i nk Observed At
North and South Sides of 37 Susitna River Check
Points,November 10-12,1980
E.3.124 Results of Marten Scat Anal yses by Season,Based
Upon Percent Frequency of Occurrence
E.3.125 Tracks of Red Foxes Encountered During November 1980
Aerial Transect Surveys
E.3.126 Red Fox Den Classification System
£.3.127 Location and Status of Raptor and Raven Ne$t Sites
in the Middle Susitna Basin,Alaska
E.3.127b Location of Raptor Nests in 'the Middle Susitna
Basin
E.3.128 Breeding Phenologies of Eagles,qyrfalcon,and
Common Raven in Interior Alaska
E.3.129 Data on Bald Eagle Nests Along the Susitna River
Between Devil Canyon and Cook Inlet
E.3.13:0;Summary of Total Numbers and Species ComposUion of
Waterbi rds Seen on Lakes Surveyed in Summer'1981 in
the Middle Susitna Basin
xi
LIST OF TABLES
E.3.131 Summary of Total Numbers and Species Composition of
Waterbirds Seen on Surveyed Waterbodies During
Aerial Surveys of the Upper Susitna River Basin,
Fall 1980
E.3.132 Summary of Total Numbers and Species Composition of
Waterbirds Seen on Surveyed Waterbodies During Aerial
Surveys of the Upper Susitna River Basin,Fall 1981
E.3.133 Summary of Total Numbers and Species Composition of
Waterbirds Senn on Surveyed Waterbodies During Aerial
Surveys of the Upper Susitna River Basin,Spring 1981
E.3.134 Seasonal Population Stat~stics for the More Important of
Surveyed Waterbodies Of the Middle Susitna River Basin,
1980-81
E.3.135 Summary of Total Numbers and Species Composition of
Waterbirds Seen During Spring Aerial Surveys of the
Lower susitna River,1981 and 1982
E.3.136 Number of Territories of Each Species on Each 10-
Hectare Census Plot,Upper Susitna River Basin,
Alaska,1981
E.3.137 Number of Territories of Each Bird Species on Each 10-
Hectare Census Plot,Upper Susitna River Basin,
Alaska 1981
E.3.138 Comparison of Breeding Bird Densities,1981 and 1982,
Middle Susitna River in Alaska
E.3.139 Habitat Descriptions of 10 Ha Avian Census Plots
E.3.140 Major Avian Habitats of the Middle Susitna Basin and
Their Most common Avian Species
E.3.141 Relative Abundance of Birds by Habitat and Vegetation
Succession Stage,Lower Susitna River Floodplain,
June 10-21,1982.Fi gures Are the Number of Bi rds
Recorded Per 100 Minutes in Each Habitat
E.3.142 Number of Small Mammels Captured Per 100 Trap Nights
During Four Sampling Periods Between August 1980 and
August 1982,Middle Susitna River Basin
xii
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LIST OF TABLES
E.3.143 Standardized Habitat Niche Breadth Values For Ten
Small Mammal Species Sampled by Snap and Pitfall
Trapping at 43 Sites,Middle Susitna River Basin,
Fall 1981
E.3.144 Time Schedule of Anticipated Impacts to Terrestrial
Vertebrates Resulting From Susitna Hydro Project
E.3.145 Anticipated and Hypothesized Impacts to Moose
E.3.146 Loss of Cover Types Commonly Used By Moose,
In Relation To Their Availability
E.3.147 Anticipated and Hypothesized Impacts to Caribou
E.3.148 Anticipated and Hypothesized Impacts to Dall Sheep
E.3.149 Anticipated and Hypothesized Impacts to Brown Bears
E.3.150 Anticipated and Hypothesized Impacts to Black Bear
E.3.151 Anticipated and Hypothesized Impacts to Wolves
E.3.152 Anticipated and Hypothesized Impacts to Wolverine
E.3.153 Anticipated and Hypothesized Impacts to
Aquatic Furbearers (Beaver and Muskrat)
E.3.154 Number of Lakes With Muskrat Pushups in Spring 1980
Occurring Within Borrow Areas and Impoundments
E.3.155 Anticipated and Hypothesized Impacts to Semi-
Aquatic Furbearers
E.3.156 Anticipated and MYpothesized Impacts on Fox
E.3.157 Anticipated and Hypothesized Impacts to Marten,
Weasel,and Lynx
E.3.158 General Types of Impacts to Raptors
E.3.159 Anticipated and Hypothesized Impacts to Raptors
and Ravens
xiii
LIST OF TABLES
E.3.160 Number of Known Raptor or Raven Nest Sites in the
Middle Susitna River Basin,Alaska,That Would Be
Inundated by the Watana and Devil Canyon Reservoirs
or That May Be Affected by Development of Associated
Access Routes and Transmission Routes
E.3.161 Raptor and Raven Nesting Locations in the Middle
Susitna Basin,Alaska,That May Be Affected By The
Susitna Hydroelectric Project Development
E.3.162 Nest Number and Status of Raptor Nesting Locations
Which Will Be Affected by the Susitna Hydro Project
and the Source of Impacts
E.3.163 Factors That Affect the Sensitivity of Raptors to
Disturbances
E.3.164 Influence of Timing of Disturbance on the Possible
Effects on Raptors
E.3.165 Approximate Losses of Avian Habitats Studied in the
Middle Susitna Basin as a Result of the Susitna
Hydroelectric Project
E.3.166 Estimated Number of Small and Medium-Sized Birds That
Would Be Eliminated Through Habitat Destruction As a
Result of the Susitna Hydroelectric Project
E.3.167 Total Average Daily Traffic on Access Road and Denali
Highway During Peak Construction Year and Season
E.3.168 State of Alaska Temporal and Spatial Protection Criteria
For Nesting Raptors
E.3.169 Estimated Mitigation ~osts for Compensation for Moose,
Brown Bear and Black Bear Foraging Habitat Loss
E.3.170 Estimated Mitigation Costs for Aerial Photography of
Vegetation in the Downstream Floodplain
E.3.171 Estimated Mitigation Costs for Bald Eagle Habitat
Modification
E.3.172 Estimated Mitigation Costs for Design,Construction,
and Placement of 10 Nest Platforms with Artificial
Nests for Golden Eagles
xiv
-
~.
-
LIST OF TABLES
E.3.173 Estimated Mitigation Costs for Design,Construction,
and Placement of 10 Nest Boxes for Cavity-Nesting
Raptors
E.3.174 Estimated Mitigation Co~ts for Modification of Cliff
Locations to Provide Golden Eagle Nesting Habitat
E.3.175 Estimated Mitigation Costs for Creating New Nesting
Cliffs for Golden Eagles
E.3.176 The Success of Artificial Nesting Structures Installed
On Power Poles and Transmission Towers
E.3.177 Botanical Resources Mitigation Summary
E.3.178 Wildlife Mitigation Summary
xv
LIST OF FIGURES
.-
-
E.3.1
E.3.2
E.3.3
E.3.4
E.3.5
E.3.6
E.3.7
E.3.8
E.3.9
Opt i on An a 1ys is
Relationship of Field Studies and IVbnitoring
to Impact Assessment and Mitigation Planning
Susitna River Drainage Basin
Susitna River and Major Tributaries From
Mouth to Little Willow Creek
Susitna River and Major Tributaries From
Montana Creek to Devil Canyon
Susitna River and Major Tributaries from
Devil Canyon to Denali Highway
Upper Cook Inlet Commerci al Salmon Managenent
Area
Population Estimates of Mult Salmon in
Susitna River
Percentage of Salmon Migrating Past Sunshine
-
E.3.10 Timing of Life Stages of Salmon in the Susitna
Rivr From Talkeetna to Devil Canyon
E.3.11 Daily Sonar Counts of Sockeye Salmon At Susitna,
Yentna,Sunshine and Talkeetna Stations
£.3.12 Slough and Tributary Index Area Peak Spawning Counts
E•3.13 S10 ug han d Trib ut ar yIn d ex Ar ea Pe a k Sp awn ing Co un t s
£.3.14 Slough and Tributary Index Area Peak Spawning Counts
E.3.15 Slough and Tributary Index Prea Peak Spawning Counts
E.3.16 Slough and Tributary Index Area Peak Spawning Counts
E.3.17 Slough and Tributary Index Area Peak Spawning Counts
£.3.18 Daily Sonar Counts of ChlJ11 Salmon at Susitna,Yentna,
Sunshine and Ta"lkeetna Stations
£.3.19 Daily Sonar Counts of Coho Salmon at Susitna,Yentna,
Sunshine and Ta"lkeetna Stations
xvi
LIST OF FIGURES
E.3.20 Daily Sonar Counts of Pink Salmon at Susitna,
Yentna,Sunshine and Talkeetna Stations
E.3.21 Waterbodies To Be Inundated By Watana Reservoir
E.3.22 Fish Spawning Times Vs.Watana
Surface Elevation
E.3.23 Waterbodies To be Inundated By Devil Canyon
Reservoir
E.3.24 Diagram of Fish Stream Crossing
E.3.25 Rehabilitated Tsusena Creek Borrow Site
E.3.26 Berm Design to Prevent Overtopping of Sloughs
E.3.27 Slough Mouth Restructured Plan
E.3.28 Design Drawing of Lowered and Restructured Slough
E.3.29 Susitna River Fishery Mitigation Induced
Upwelling Using Tributary Water Supply
E.3.30 Susitna River Fishery Mitigation Main Stream
Spawning Bed
E.3.31 Schematic Grayling Hatchery
E.3.32 Study Area for Botanical Resources and Wildlife
E.3.33 Vegetation Mapping Areas of the Susitna
River Basin
E.3.34 Locations of Stands Sampled on Downstream
Floodplain of the Susitna River,1981
E.3.35 Vegetation Mapping Areas for Transmission Corridors
E.3.36 The Watana and Gold Creek Watersheds With Major
Water Bodi es
E.3.37 Location of Project Facilities
E.3.38 Vegetation Map of Upper Susitna River Basin
E.3.39 Vegetation Map of Susitna Project Impact Areas
xvii
p:::--',
.....
LI ST OF FI GUR£S
E.3.40 Vegetation Map of Susitna Project Impact Areas
E.3.41 Vegetation Map of Susitna Project Impact Areas
E.3.42 Vegetation Map of Proposed Susitna Hydroelectric
Access Corri dors
E.3.43 Vegetation Map of Proposed Susitna Hydroelectric
Access Corridors
£.3.44 Vegetation Map of Proposed Susitna Hydroelectric
Access Corri dors
E.3.45 Wetland Map of Susitna Hydroelectric Project
Access Corridors
E.3.46 Wetland Map of Susitna Hydroelectric Project
Access Corri dors
E.3.47 Wetland Map of Susitna Hydroelectric Project
Access Corri dors
E.3.48 Vegetation Map of Proposed Healy-Fairbanks
Transmission Corridor
E.3.49 Vegetation Map of Proposed Healy-Fairbanks
Transmission Corridor
E.3.50 Vegetation Map of Proposed Healy-Fairbanks
Transmission Corridor
E.3.51 Vegetation Map of Proposed Willow-
Cook Inlet Transmission Corridor
E.3.52 Vegetation Map of Proposed Willow-
Cook Inlet Transmission Corridor
E.3.53 Vegetation Map of Susitna Project Impact Areas
£.3.54 Vegetation Map of Susitna Project Impact Areas
E.3.55 Vegetation Map of Susitna Project Impact Areas
E.3.56 Vegetation Map of Susitna Project Impact Areas
E.3.57 Vegetation Map of Susitna Project Impact Areas
xviii
LIST OF FIGURES
E.3.58 Vegetation Map of Susitna Project Impact Areas
E.3.59 Vegetation Map of Susitna Project Impact Areas
E.3.60 Vegetation Map of Susitna Project Impact Areas
E.3.61 Vegetation Map of Susitna Project Impact Areas
E.3.62 Vegetation Map of Susitna Project Impact Areas
E.3.63 Vegetation Map of Susitna Project Impact Areas
E.3.64 Vegetation Map of Susitna Project Impact Areas
E.3.65 Vegetation Map of Susitna Project Impact Areas
E.3.66 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.67 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.68 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.69 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.70 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.71 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.72 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.73 Wetland Map of Susitna Hydroelectric Project
Impoundment Area and Borrow Sites
E.3.74 Vegetation Sample Locations in Susitna River
Basin,1980
E.3.75 Locations of Lakes and Ponds Surveyed for Vascular
Aquatic Plants in August 1980
E.3.76 A Schematic Representation of the Dominant Vegetation
Associated With Many of the Lakes and Ponds of the
Susitna Basin
xix
p,---.
....
....
-
....
""'"
""'"
I
.....
....
LI ST OF FIGURES
E.3.77 Patterns of Forest Succession Following
Fi re In Al aska
E.3.78 Primary Succession on the Susitna Floodplain
E.3.79 Adjustments to Road/Railroad Alignments
Index Map
E.3.80 Adjustments to Road Alignment
E.3.81 Adjustments to Road Alignment
E.3.82 Adjustments to Road and Railroad Alignments
E.3.83 Comparison of Road Construction Techniques
E.3.84 Typical Hillside Cut of Railroad Cross Section
E.3.85 Typical Transmissi~n Right-of-Way Cross section
E.3.86 Locations of Radio-Collared Cow Moose During
Parturition (May 15-June 15)From 1977 Through 1981
E.3.87 Locations of Radio-Collared Moose During The Rut
(September 20-0ctober 20)From 1977 Through Fall 1980
E.3.88 General Movement and Migration Patterns of Radio-
Collared Moose From October 1976 Through Mid-August 1981
E.3.89 Boundaries of Established Moose Count Areas
E.3.90 Zones Employed To Estimate Moose Densities Within
Riparian Communities Along the Susitna River
E.3.91 Dates of Mortalities of Collared and Uncollared Moose
Calves During 1977,1978 and 1980 In The Nelchina and
Upper Susitna Basin,Alaska
£.3.92 Historical Range of the Nelchina Caribou Herd
E.3.93 Distribution of Nelchina Radio-Collared Caribou During
Calving Period,May 15 Through June 10,1980 and 1981
E.3.94 Location of Radio-Collared Caribou In Subherds,
May 9,1980,Through September 22,1981
E.3.95 Seasonal Elevation Use By Caribou From Nelchina Head
xx
LIST OF FIGURES
E.3.96 Calf Survival Compared to Wolf Numbers
And Total Caribou
E.3.97 Location of Dall Sheep Study and Aerial
Survey Areas
E.3.98 Suspected Locations and Territorial Boundaries
Of Wolf Packs Inhabiting The Susitna Hydroelectric
Project Area during 1980 and 1981
E.3.99 General Location and Year of Use of Observed Wolf
Den and Rendezvous Sites Discovered in the Susitna
Hydroelectri c Project Area From 1975 Through 1981
E.3.100 Observed Home Ranges of ~olverines In The Middle
Susitna Basin Based on Location of Radio-Collared
.Animal s
E.3.101 Aerial Transects for Furbearers and Checkpoints
For Otter and Mink Sign
E.3.102 Locations and Classification of Fox Dens
E.3.103 Locations of 12 Bird Census Plots in the Middle
Susitna River Basin
E.3.104 Locations of Important Lakes and Lake Groups
Surveyed for Waterfowl in the Middle Susitna
Basi n
E.3.105 Importance Values of Waterbodies for Migrant
Waterfowl in the Middle Susitna Basin,Upper
Tanana River Valley,and Scottie Creek Area
Fall 1980
E.3.106 Importance Values of Waterbodies for Migrant
Waterfowl in the Middle Susitna Basin,Upper
Tanana River Valley,and Scottie Creek Area
Spring 1981
E.3.107 Clustering of 42 Small Mammal Trapline Sites
Into Similar Vegetative Groupings,Based on an
Analysis of Frequency Counts of 81 Plant Taxa
In the Ground Cover
E.3.108 Abundance Patterns of Eight Small Mammal Species
Relative To Vegetation Types at 42 Sites in the
Susitna River Basin,Alaska,July 29-August 30,1981
xxi
(=.-
-
.....
LIST OF FIGURES
E.3.109 Probable Factors Regulating Moose Populations in the
Susitna Basin and Actions That Might Affect These
Populations
E.3.110 Probable Factors Regulating Brown Bear Populations
in the Susitna Basin and Actions That Might Affect
These Populations
E.3.111 Probable Factors Regulating Black Bear Populations
in the Susitna Basin and Actions That Might Affect
These Populations
E.3.112 Probable Factors Regulating Wolf Populations in the
Susitna Basin and Actions That Might Affect These
Populations
E.3.113 Probable Factors Regulating Beaver Populations in the
Susitna Basin and Actions That Might Affect These
Populations
E.3.114 Probable Factors Regulating Marten Populations in the
Susitna Basin and Actions That Might Affect These
Populations
E.3.115 Elevations of Raptor and Raven Nests in the Vicinity
of the Watana Impoundment Area in Relation to Filling
and Operation Water Levels
E.3.116 Changes in Elevation of the Devil Canyon Reservoir
During Operation and Elevations of Raptor and Raven
Nests "in the Proximity of the Impoundment Zone
E.3.117 Relative Amounts of Moose Browse Available Compared
With The Time Since Fire or Other Disturbance in
Interi or Al aska
E.3.118 Eagle Nesting Platforms to be Provided on Transmission
towers
E.3.119 Ground Wire Gapping Designed to Protect Raptors From
El ectrocut ion
E.3.120 Armless Configurations Designed to Protect Raptors
From Electrocutions
E.3.121 Installation of Transformer Equipment to Provide for
Raptor Perching
!'"""xxi i
LIST OF FIGURES
E.3.122 Perch Guards Designed to Protect Raptors From
Electrocution
E.3.123 Elevated Perch Construction Designed to
Protect Raptors from Electrocution
xxiii
,~'-l
~I
""""I
I
-
-
.....
,-
-
3 -FISH,WILDLIFE,AND BOTANICAL RESOURCES
1 -INTRODUCTION
This report discusses the fish,vegetation,and wildlife resources of
the area that wi 11 be affected by the proposed Susi tna Hydroe1ectri c
Project.Each of the major subsections (2 -Fish,3 -Botanical
Resources,and 4 -Wi 1d1ife)provides a baseline description of species
and populations of the project area;an assessment of potential project
impacts on this biota (assuming no mitigation);and a mitigation plan
that explains how preliminary engineering design and construction plan-
ning have incorporated measures to avoid,minimize,or rectify poten-
tially adverse effects of the project on the biological environment.
In appropri ate cases,resource management opti ons to reduce or
compensate for adverse impact s that cannot otherwi se be mi ti gated are
di sc us sed.
1.1 -Baseline Descriptions
These secti ons descri be the di stri buti ons and characteri sti cs of bi 0-
1ogi cal popu1 ati ons and communi ti es wi thi n the project area.The di s,-
cussions are based on a thorough review of the scientific literature
and emphasi ze documented studi es conducted in preparati on for the
Susitna Hydroelectric Project by the Alaska Department of Fish and Game
and professional consultants.They provide the most current avai 1able
information through December 1982 on fish,vegetation,a,nd wildlife of
the project area.
Di scussi ons of ani rna 1s focus on vertebrate speci es:resi dent and anad-
romous fish,big game,furbearers,birds,and non-game (small)mammals.
The plant descriptions deal with species aggregations that occur in
recogni zab1e patterns,such as vegetati on communiti es and successi onal
stages .'
The base1i ne descri pti ons emphasi ze functi onal re1 ati onshi ps among
habitat components and animal communities.Factors that regulate
speci es di stri buti on and abundance recei ve parti cu1 ar attenti on,
because know1 edge of these regu1 ati ng mechani sms can suggest where
populations are most sensitive to potential disturbance.For example,
water temperature and stream regi mes are di scussed as regul ators of
fish populations,and the role of plant communities in regulating wi1d-
li fe popu1 ati ons is ex ami ned.
1.2 -Impact Assessments
It is expected that the di stri buti on and abundance of fi sh,plant,and
wi 1dli fe speci es in and around the area of the Susi tna Hydroe1ectri c
Project wi 11 change as a result of project construction and operation.
E-3-1
1.2 -Impact Assessments
The impact assessments presented in this report are based,in part,on
t he project descri pti on presented in Exhi bi t A,project operati ons des-
cribed in Exhibit B,the proposed construction schedule shown in
Exhibit C,and an analysis of similar activities associated with large
construction and hydroelectric projects in similar habitats.In addi-
tion,the Recreation Plan presented in Exhibit E,Chapter 7,has been
revi ewed as a proposed project acti on to determi ne its potenti a1
impacts on fi sh,vegetati on,and wi ldli fe.The impact assessments li nk
predicted physical changes with habitat utilization to provide a quali-
tative statement of impacts likely to result from the Susitna Hydro-
electric Project.Quantitative assessments are presented where justi-
fied by current knowledge and research techniques.Changes potentially
resulting from the project are di scussed with respect to specific proj-
ect features and acti viti es,assumi ng standard engi neeri ng desi gn and
construction practice without the incorporation of mitigation measures.
Much of the di scussi on is based on professi onal judgment.Data collec-
ti on and analysi s programs currently underway wi 11 refi ne several of
the impact assessments as expl~ned in the text.
Although some project impacts,if not mitigated,wi 11 be adverse,other
impacts wi 11 be innocuous and some wi 11 enhance fi sh or wi ldli fe pro-
ducti vity.Therefore,potenti ally benefi ci al impacts are gi ven bal-
anced treatment with those to be mitigated.Each potenti al effect,
together with the action responsible for it,is called an impact
issue.
The identification and prioritization of impact issues have followed
the procedures establi shed by the Susi tna Hydroelectri c Project Fi sh
and Wildlife Mitigation Policy (Alaska Power Authority 1982;Appendix
3.A).This policy was prepared by the Power Authority through a
Fisheries Mitigation Core Group,a Wildlife Mitigation Core Group,and
a Fi sh and Wi ldli fe Mi ti gati on Revi ew Group.The core groups,consi s-
ti ng of professi onal consultants and agency representati ves,developed
the technical specifics of the mitigation policy.The review group.
whi ch consi sts enti rely of state and federal agency representati ves,
evaluated draft stages of the mitigation policy and provided comments
that were incorporated through successive revisions.The review group
included representatives of the following resource agencies:
-Alaska Department of Fi sh and Game (ADF&G);
-Alaska Department of Natural Resources (ADNR);
-Nati onal IVlari ne Fi sheri es Servi ce (NMFS);
U.S.Bureau of Land Management (USBLM);
-U.S.Environmental Protection Agency (USEPA);and
-U.S.Fi sh and Wi ldlife Servi ce (USFWS).
In addition to procedures outlined in the Susitna Hydroelectric Project
miti gati on poli cy,criteri a for assessi ng the rel ati ve importance of
biological impact issues have been provided by (1)mitigation policies
of the Alaska Department of A sh and Game (1982a)and the U.S.~sh and
E-3-2
-
--
.....
1.3 -Mi t i gat i on Plan s
Wi 1d 1i fe Servi ce (1981);(2)1etters and testi many by the Al aska
Department of Fi sh and Game (1980,1982b,1983),the Alaska Department
of Natural Resources (1982),the U.S.Fish and Wi ldlife Service (1979,
1980,1981a,1981b,1982a-d,1983),and the Susi tna Hydroelectri c
Steering Committee (1981,1982);and (3)discussions of impact issues
in workshops (ESSA/WELUT!LGL 1982)and numerous other techni cal meet-
ings involving Susitna project personnel and resource agency represen-
tatives.
All three mitigation policies imply that project impacts on the habi-
t at s of cert ai n sensiti ve fi sh and wi 1d 1ife speci es wi 11 be of greater
concern than changes in distribution and abundance of less sensitive
species.Sensitivity can be related to high human use value as well as
suscepti bi lity to change because of project impacts.The poli ci es and
comments also indicate that,for the Susitna Project area,vegetation
is considered more important as a component of wi ldlife habitat than as
a botanical resource in itself.Statewide policies and management
approaches of resource agencies suggest that concern for fish and wi ld-
li fe speci es wi th commerci al,subsi stence,and other consumpti ve uses
is greater than for species without such value.These species are
often large,sometimes numerous,and uti lize a wide range of habitats,
as well as havi ng hi gh human use val ue.Such characteri sti cs often
result in these species being selected for careful evaluation when
their habitats are subjected to alternative uses.By avoiding or mini-
mizing alterations to habitats utilized by these evaluation species,
the impacts to other less sensitive species that utilize similar habi-
tats can also be avoided or reduced.
The miti gati on po li ci es a 11 agree th at resource vul nerabi lity is an
important criterion for impact prioritization.Resources judged most
vulnerable to potential project impacts have therefore been given high-
est priority in impact assessment and mitigation planning.Simi larly,
impact issues have been considered with regard to probabi lity of occur-
rence.Where there is a high degree of confidence that an impact wi 11
actually occur,it has been ranked above impacts that are predicted to
be less li kely to occur.Al so,the miti gati on polici es and agency com-
ments indicate that impacts on animal productivity and population size
through changes in habitat avai labi lity are of high concern.Behav-
ioral responses that have the potenti al for producing population-level
effects are also important.Adverse impacts that are longer lasting or
irreversible have priority over short-term impacts.
1.3 -Mitigation Plans
Mitigation plans have been developed for identified impact issues in
accordance with the sequence of steps defined by 40 CFR 1508.20,pur-
suant to the National Environmental Policy Act (42 USC 4321 et seq.)•
E-3-3
1.3 -Mi ti gati on Pl ans
The mitigation planning sequence includes,in priority order of imple-
mentati on,the followi ng steps:
-Avoiding the impact through project design and operation,or by not
t aki ng a certai n acti on;
-Mi ni mi zi ng the impact by reduci ng the degree or magnitude of the
acti on,or by changi ng its locati on;
-Recti fyi ng the impact by repai ri ng,rehabi li tati ng,or restori ng the
affected portion of the environment;
Reducing or eliminating the impact over time by preservation,moni-
tori ng,and mai ntenance operati ons duri ng the li fe of the acti on;
and
-Compensating for the impact by providing replacement or substitute
resources that would not otherwi se be avai 1able.
Thi s sequenti al strategy for mi ti gati on opti on analysi sand i mplementa-
tion is shared by all three mitigation policies applied to the project
(Alaska Power Authority 1981,ADF&G 1982a,USFWS 1981).The relation-
shi ps of steps wi thi n the sequence are shown in Fi gure E .3.1 and fur-
ther compared in Table E.3.1.
The process by whi ch mi ti gati on wi 11 be implemented and conti nually
refined throughout the life of the project is shown schematically in
Figure E.3.2.The process involves the following steps:
-Impact issue evaluation:
.Identi fi cati on of the nature and extent of impacts:
Popul ati ons
Subpopulations
Habi t at types
Geographical areas
Pri ori ti zati on of impacts:
Ecological value of affected resource
Consumptive value of affected resource
Resource vulnerabi lity
Confidence of impact prediction
Long-term vs.short-term impacts
-Option analysis procedure:
Identification of practicable mitigation options:
Type of mitigation option
..Sequence of implementation
E-3-4
-
-
-
Ii"'"
..,...,
-
1.3 -Mitigation Plans
·Evaluation of mitigation options:
Effectiveness of option
..Conflicts with project objectives
..Resi dual impacts
·Documentation of option analysis:
Impact issues
..Mi ti gati on opti ons
..Conflicts (if any)with project objectives
-Mi ti gat i on plan i mp 1ement at i on:
•Engineering design and construction planning:
Parti ci pate in desi gn deve 1opment
Participate in preconstruction field surveys and site
evaluations
Review de~gns,schedules,permit applications
Construction and operation monitoring:
Review work accompli shed
Evaluate degree of impact
Evaluate effectiveness of mitigation
Identi fy modi fi cati ons to the mi ti gati on pl an
Submit regularly scheduled reports
·Mitigation plan modifications:
Propose modi fi cati ons
Submit modifications for review
..Implement and monitor approved modifications
Data from the baseli ne,impact,and moni tori ng studi es wi 11 be used
throughout the life of the project by the mitigation core and review
groups to pl an and conti nually ref-i ne the miti gati on process ina flex-
i ble,adapti ve fashi on.
Miti gati on measures proposed for the Su si tna Hydroe 1ectri c Proj ect may
be cl assi fi ed wi thi n two broad categori es:
-Modifications to design,construction,or operation of the project;
and
-Resource management strategies.
The first type of mitigation measure is project-specific and emphasizes
the avoidance,minimization,rectification,or reduction of adverse
impacts,as prioritized by the Fish and Wildlife Mitigation Policy
establi shed by the Power Authori ty (l982)and coordi nati ng agenci es
(ADF&G 1982a,USFWS 1981).As shown in Figure -E.3.1,these measures
must first be implemented to keep adverse impacts to the minimum
E-3-5
1.3 -Mitigation Plans
consi stent wi th project requi rements.They i nvo lve adjusti ng or addi ng
project features duri ng desi gn and p1anni ng so that mi ti gati on becomes
a b~It-in component of project actions.
When impacts cannot be fully avoided or rectified,reduction or compen-
sation measures are justified.This type of mitigation can involve
management of the resource itself,rather than adjustments to the proj-
ect,and will require concurrence of resource management boards or
agenci es wi th juri sdi cti on over 1ands or resources wi thi n and around
the project area.
Mitigation planning for the Susitna Hydroelectric Project has empha-
sized both approaches.The prioritized sequence of options from avoid-
ance through compensati on has been appli ed to each impact issue.If
full mitigation can be achieved at a high priority option,lower
options may not be considered.In the resulting mitigation plans,
measures to avoid,minimize,or rectify potential impacts are treated
in greatest detail.Specifications for facility siting and design,
speci a 1 mi ti gati on faci li ti es,constructi on procedures,and scheduli ng
of project actions to mitigate adverse effects on the biota are pre-
sented.Guidelines for these specifications are summ~rized in Appendix
3.A.
Moni tori ng and mai ntenance of mi ti gati on features to reduce impacts
over time are recognized as an integral part of the mitigation
process.The monitoring program will be developed during detailed
engineering design and construction planning and wi 11 apply to fish,
botani cal resources,and wi ldli fe.
long-term management strategi es for impact mi ti gati on are di scussed as
potenti al opti ons.The Power Authority is committed to evaluate and
recommend such resource management options,and is sponsoring continu-
i ng research to defi ne thei r need and appli cati on.Fi nal agreement on
measures wi 11 requi re interagency coordi n ati on.
E-3-6
....
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,..
2 -FISH RESOURCES OF THE SUSITNA RIVER DRAINAGE
2.1 -Overview of the Resources
2.1.1 ~Description of the Study Area for Fish Resources
The study area for the Susitna Hydroelectric Project fish studies
includes the Susitna River mainstem,side channels,sloughs,and
mouths of major tributaries (Figure E.3.3).From the terminus of
Susitna Glacier in the Alaska Mountain Range to its mouth in Cook
Inlet,the Susitna River flows a pp roximat 2l y 318 miles (530 km)
and drains 19,600 square miles (50,900 km).The mainstem and
major tributaries of the Susitna River,including the Maclaren,
Chulitna,Talkeetna and Yentna Rivers,originate in glaciers 'and
carry a heavy load of glacial flour during the ice-free months.
There are many smaller,clear water tributaries that are
perennially silt-free,except during floodflows,including Tyone
River,Oshetna River,Portage Creek,Indian River,Kroto Creek
(Deshka River)and Alexander Creek (Figures E.3.4 to E.3.6).
Streamflow is characterized by moderate to high flows between May
a nd September and low flows from October to April.Hi gh surrmer
discharges result from snowmelt,rainfall and glacial melt.
Winter flows are almost entirely ground water inflow (see Chapter
2,Section 2.2.3).Freezeup begins in the higher regions in
early October,and most of the river is ice free by late May.
Three study reaches have been defined for baseline data gathering
and impact analysis based,upon stream morphology,flow regime and
anticipated impacts.These study reaches are:the impoundment
from the Oshetna River (River ~ile [RM]236)to Devil Canyon (RM
152),Devil Canyon to Ta"lkeetna(RM 98);and Ta'lkeetna to Cook
I n1et (RM 0).
2.1.2 -Data Collection and Analysis Methods
-
-
....
I
(a)Anadromous Adult Investigations
Methods uti 1i zed duri ng 1981 and 1982 to enumerate adul t
salmon within the Susitna River drainage included side-scan
sonar monitoring,fishwheel monitoring,tag and recapture
estimates and ground/aerial spawning surveys.
Side-scan sonars and fi shwheel s were used to determine the
upstream migration timing of sockeye,pink,chum,and coho
salmon in the Susitna River from July through early to mid-
September 1981 and 1982 at Susitna Station (RM 26),Yentna
Station (Yentna RM 04),Sunshine Station (RM 80)and
Talkeetna Station (RM 103)(ADF&G 1982a,Figures E.3.4 and
E.3.5).The species composition of the daily catch of a
nearby fishwheel was used to apportion side scan sonar
counts.Fishwheels were also operated at Curry Station (RM
120),but without associated sonar counters.
2.1 -Overview of Resources
The side-scan sonar counts recorded at Susitna Station were
not used for defining susitna River salmon escapements be-
cause of suspected inaccuracy of counts caused by counter
siting problems.Details of these problems are discussed in
ADF&G (1983).Yentna Station (RM 04)sonar counts were con-
sidered suitable for reporting 1981 and 1982 Yentna River
salmon escapements (ADF&G 1983).
A tag/recapture program was conducted to estimate numbers of
the five salmon species passing upstream of Sunshine,
Tal keetna and Curry Stations during 1981 and 1982 (ADF&G
1981a,1982e).Salmon captured by fishwheels at the above
sampling sites were measured,scales were removed for aging,
then the fish were fitted with tags,color-coded for each
site and released.Personnel surveyed all known and sus-
pected salmon spawning tributaries (15)and sloughs (34)
from RM 101.4 to 148.8 of the Susitna River at weekly inter-
val s from 1ate July through early October.All tagged and
untagged salmon were counted.Species population estimates
were then calculated from survey and fishwheel catch data at
each station.
Salmon abundance within the entirety of sloughs and selected
tributary index reaches was determined by the above surveys
during 1981 and 1982.The tributary index reaches were
within 0.5 mile (0.8 km)of the confluence with the Susitna
River.
Spawning chinook salmon were counted from helicopters during
1981 and 1982 in the Indian River (RM 128.6)and Portage
Creek (RM 148.8).Cheechako Creek (RM 152.5)and an unnamed
creek (RM 156.8)were also surveyed in 1982.Other Susitna,
Chulitna,and Talkeetna River drainage chinook salmon spawn-
ing areas were surveyed as part of an ongoing project since
1975 to determine chinook salmon escapement trends in the
Cook Inlet drainage (ADF&G 1982a).The suitability of heli-
copter surveys as a census method for chinook salmon is dis-
cussed in Neilson and Green (1981)••
;
Sockeye,chum,pink and coho salmon spawning activity in
mainstem,side-channel,and tributary confluence locations
of the lower and middle Susitna River was evaluated by a
variety of techniques during 1981 and 1982 including:ob-
servation,electroshocking,drift gill netting,and egg
pumping (ADF&G 1982a,1982e).Egg pumping occurred after
fish spawning activity terminated.
Adult chinook,chum,and coho salmon were fitted with inter-
nal radio transmitters at Talkeetna and Curry in 1981 and
E-3-8
2.1 -Overview of Resources
1982.These fish were followed to evaluate directional
movements,upstream migration rates,upstream migration
extent,and spawning locations.
Stat i onary gill nets were ope rated nea r Devil Canyon at
RM 150.2 at five-day intervals from late July to mid-
September 1981 and 1982 to detect adult sockeye,chum,pink,
and coho salmon.
-
(b)
The migration timing,upstream migration extent,and pro-
bable spawning areas of eu1achon in the Sustina River were
evaluated from mid-May through mid-June 1982 by a variety of
techniques.Upstream mi grat ion timi ng was assessed by sta-
tionary gill nets placed at selected Susitna River estuary
locations.The extent of upstream migration was determined
by di P net and e1 ectrofi shi ng.Eu1 achon spawni ng habitat
.was determined directly by searching for eggs in substrate
samples and indirectly by evaluating the spawning condition
of female smelt'collected by dip net and e1ectrofishing at
suspected spawning sites.
During 1981 and 1982 the migration timing,upstream migra-
tion extent,and spawning habitat selection of Bering cisco
in the Susitna River were investigated.A fishwhee1 used
for salmon investigations was maintained through late
September 1981 and 1982 to intercept cisco.E1ectrofishing
was used to assess the upstream migration extent and spawn-
ing habitat selection by cisco,as evidenced by spawning
condition of captured fish.
Resident and Juvenile Anadromous Fish Investigations
Fish investigations also assessed the seasonal distribution
and relative abundance of resident and juvenile anadromous
fish ln the Susitna River downstream from Devil Canyon (RM
152).Methods include baited minnow traps,trot (i.e.,set)
1i nes,hook and 1i ne,elect rofi shi ng,stat i ona ry and dri ft
gill nets,and beach sei~s.Studies commenced in November,
1980 and are continuing.Selected tributaries and tributary
confluences,sloughs,side-channel and mainstream locations
from RM 10.1 to 148.8 of the Susitna River were sampled dur-
ing the winter (November to April)and the open-water season
(May to October).Fewer sites were sampled during the win-
ter than duri ng the open-water season because of samp1 i ng
constraints,including the short length of daylight,and ice
cond it ion s•
Captured fi sh were processed
respective capture locations.
inches (200 mm)in fork length
numbered tags.
E-3-9
and returned alive to their
All resident fish exceeding 8
were tagged with individually
2.1 -Overview of Resources
Lotic habitats at resident and juvenile anadromous fish
sampling sites were described at the time of sampling to
correlate seasonal fish distribution and abundance trends to
selected physical/chemical lotic habitat components.Habi-
tat variables measured included water temperature,dissolved
oxygen,conductivity,turbidity,water depth,velocity and
instream cover (ADF&G 1981c and 1982a).
Electrofishing was conducted during the 1982 open-water sea-
son along the Susitna River from Cook Inlet to Devil Canyon
(RM 152)to tag res i dent fi sh and evaluate thei r seasonal
distribution and movements within the Susitna River.
Individually identifiable radio transmitters of three-to-six
months longevity were surgically implanted in adult rainbow
trout and burbot from August through early October of 1981
and 1982 at various locations along the Susitna River down-
stream from Devil Canyon (RM 152).These tags were used to
evaluate autumn and winter movements and overwintering loca-
tions.Conventional winter fish sampling techniques,
under-ice submerged gill net sets and baited tip-ups,were
used to detect non-radio-tagged burbot and rainbow trout.
A smolt trap was operated just upstream from Tal keetna at
RM 103 from mid-June through early October 1982 to measure
the out-migration of juvenile salmonids from the reach above
Tal keetna.
St ud i es were cond ucted upst ream from Dev il Canyon (RM 152)
to evaluate the seasonal distribution and abundance of
Arctic grayling.Eight major clear-water tributaries,
located between RM 173.9 and 226.9,were sampled monthly
from June to September duri ng 1981 and 1982.Arctic gray-
ling exceeding 8 inches (200 mm)in fork length were tagged
with individually numbered tags.Seasonal movements and
population estimates were derived from fish recapture data.
Segments of the lower one mil e of the above streams were
sampled for arctic grayling during 1981,whereas the entire
reaches of six of the eight streams that would be inundated
by the Watana impoundment were sampled during 1982.
Fish were sampled by baited minnow traps,trot lines and
sei ne along the ei ght tri butari es duri ng 1981 and 1982 to
detect the presence of other resident fishes.Selected
physical/chemical lotic habitat data were collected along
these tributaries during 1981 and 1982.
E-3-10
2.1 -Overview of Resources
-
-
2.1.3 -Threatened and Endangered,Species
No threatened or endangered species of fish
in Alaska.The USFWS (1982)does not list
Al aska as bei ng threatened or endangered.
Endangered Speci es Act al so does not 1i st
endangered.
2.1.4 -Overview of Important Species
have been identified
any fish species in
The state of Al aska
any fish species as
-
-
---
Fishery resources in the Susitna River comprise a major portion
of the Cook Inlet commercial salmon harvest and provide sport
fishing for residents of Anchorage and the surrounding area.
Anadromous speci es that form the base of commerci al and non-
commercial fisheries include five species of Pacific salmon:
chinook,coho,chum,sockeye,and pink.Other anadromous species
include eulachon and Bering cisco.
Important resident species found in the Susitna River drainage
include arctic grayling,rainbow trout,lake trout,burbot,Dolly
Varden,and round whitefi sh.Scientific and common names for all
fish species identified from the Susitna ,drainage are listed in
Table E.3.2.
The Susitna River is a migrational corridor,spawning area,and
juvenile rearing area for five species of salmon from its point
of discharge into Cook Inlet to Devi]Canyon,where salmon are
usually prevented from moving upstream by the water velocity at
high discharge.The majority of the 1981 and 1982 Susitna River
escapement of sockeye,pink,chum,and coho salmon spawned above
the Yentna River confluence and below Curry Station.Sloughs
between Devil Canyon and Talkeetna provide spawning habitat for
pink,sockeye,and chum salmon.Juvenile chinook and coho salmon
occur throughout the river below Devil Canyon,concentrating at
slough and suitable mainstem habitat during winter and at tribu-
tary mouths during summer.
Rainbow trout and Dolly Varden were recorded at mouths of tribu-
tary streams.Rainbow trout do not occur upstream from Devil
Canyon.Arctic grayling are the dQminant species upsteam from
Devil Canyon.
2.1.5 -Contribution to Commercial and
Non-commercial Fishery
(a)Commerci al
Figure E.3.7 shows the ADF&G upper Cook Inlet salmon harvest
statis,tical areas.The upper and lower Cook Inlet commer-
cial fishery harvests mixed stocks (Tables E.3.3 and E.3.4).
E-3-ll
2.1 -Overview of Resources
With the exception of sockeye salmon,the majority of upper
Cook Inlet Salmon production originates in the Susitna
drainage (ADF&G 1982b).The long-term average annual catch
of 2.8 million fish is worth approximately $17.9 million
(ADF&G 1982b).The Susitna River is considered the most
important salmon-producing system in upper Cook Inlet;how-
ever,the quantitative contribution of the Susitna River to
the commercial fishery can only be estimated because of:
The hi gh number of intra -drai nage spawni ng and reari ng
areas;
-The 1ack of data on other known and suspected sal mon-
producing systems in upper Cook Inlet;
-The lack of stock separation programs (except for sockeye
salmon);and
Overlap in migration timing of mixed stocks and species in
Cook Inlet harvest areas.
Therefore,the fall owi ng di scuss i on of the contri but i on of
the Susitna River to the upper Cook Inlet fishery as influ-
enced by the above limitations is based upon:
Historical sustained harvest in upper Cook Inlet;
-Escapement data from the ADF&G Susitna River tag/recapture
studies for 1981 and 1982;and
-Convers i on of the 1981·and 1982 escapement data past
Tal keetna to an estimate of catch associated with that
escapement usi ng long-tenn average harvest to escapement
ratios presented in Friese (1975).
Further discussion of the commercial salmon harvest is con-
tained in Chapter 5,Section 3.7.l(b).
(i)Sockeye
The commercial sockeye harvest has averaged approxi-
mately 1.11 million fish annually in upper Cook
Inlet over the last 28 years (Table E.3.3).The
estimated 1981 and 1982 catches were 1.44 million
and 3.24 million,respectively.The 1982 catch was
the highest in the 29 years of record.
E-3-12
-
,....
i
2.1 -Overview of Resources
The estimated sockeye escapement in the reach above
Talkeetna was 4800 in 1981 and 3100 in 1982 (Table
E.3.5,Figure E.3.8).These represented 3.6 percent
and 2.°percent of the estimated sockeye escapement
past Sunshine Station (Figure E.3.9).These escape-
ments represent an estimated commercial catch of
14,400 in 1981 and 9300 in 1982,assuming a 3.0:1
harvest to escapement ratio (Friese 1975).
-
(i i )
(i i i )
Chum
The upper Cook Inlet chum salmon catch has averaged
approximately 614,000 fish annually since 1954 (Table
E.3.3).The 1981 and 1982 estimated catches were
843,000 and 1 ~430,000,respectively.The 1982 catch
of chum salmon was also the highest for the 29 years
of record.
The 1981 and 1982 estimates of chum salmon escapement
in the reach above Talkeetna were 20,800 and 49,100
(Table E.3.5.,Figure E.3.8).These represented 7.9
percent and 11.4 percent of the estimated chum es-
capement past Sunshine Station (Figure E.3.9).These
escapements represent an estimated commerci al catch
of 45,800 in 1981 and 108,000 in 1982,assuming a
2.2:1 harvest to escapement ratio (Friese 1975).
Coho Salmon
Since 1954,the upper Cook Inlet coho salmon commer-
cial catch has averaged approximately 230,000 fi sh
(Table E.3.3).The estimated 1981 and 1982 catches
were 494,000 and 777,000,respectively,with the 1982
catch the highest during the 29 years of record.
The 1981 and 1982 estimates of coho salmon escapement
in the reach above Talkeetna were 3300 and 5100
(Table E.3.5,Figure E.3.8).These represented 16.7
percent and 11.1 percent of the estimated coho es-
capement past Sunshine Station (Figure E.3.9).These
escapements represent an estimated commerci a1 catch
of 7300 in 1981 and 11,200 in 1982,assuming a 2.2:1
harvest to escapement ratio (Friese 1975).
-
-
(iv)Pink Salmon
The upper Cook Inl et annual,average,odd-year har-
vest of pink salmon since 1954 is about 124,000 with
a range of 12,500 to 554,000,while the average even-
year harvest is approximately 1,701,000 with a range
E-3-13
2.1 -Overview of Resources
of 484,000 to 3,232,000 (Table E.3.3).The 1981 and
1982 catches were 128,000 and 789,000,respectively.
The 1982 catch was the thi rd lowest even-year catch
recorded during the 29 years of record.
The estimates of pink salmon escapement in the reach
above Talkeetna were about 2300 in 1981 and 73,000 in
1982 (Table E.3.5,Figure E.3.8).These represented
4.6 percent and 16.5 percent of the pi nk escapement
past Sunshine Station (Figure E.3.9).These escape-
ments represented an estimated conmerci a1 catch of
8700 in 1981 and 278,000 in 1982,assuming a 3.8.1
harvest to escapement ratio (Feiese 1975).
(v)Chinook
Since 1954,the commercial catch of Chinook salmon in
upper Cook Inlet has averaged 19,500 (Table E.3.3).
T~e upper Cook Inlet"harvests for 1981 and 1982 were
11,500 and 20,600,respectively.Since 1964,the
opening date of the commercial fishery has been June
25,and the Susitna River chinook salmon run begins
in 1ate l"1ay and peaks in mi d-J une.Thus,the maj or-
i ty of chi nook have al ready passed through the area
subject to commercial fishing.Estimates of chinook
sal man escapement in the reach above Tal keetna were
10,900 in 1982 (Table E.3.5,Figure E.3.8).This
represented 22.0 percent of the chi nook escapement
past Sunshine Station (Figure E.3.9).
(b)Non-Commercial Fishing
(i)Sport Fishing
Recent increases in population and tourism in Alaska
have resulted in a growing demand for recreational
fi sh i ng.Recreat i ona 1 fi shi ng is now cons i de red a
significant factor in total fisheries management,
especi ally in Cook Inl et where cOlllTlerci al and non--
conmercial user conflicts have developed (Mills
1980).The Susitna River and its major salmon and
resi dent fi sh-produci ng tri butary streams provide a
multi-species sport fishery easily accessible from
Anchorage and other Cook Inlet conmunities.In 1978,
the Susitna Ri ver and its primary tri butari es
accounted for over 124,000 angler days of sport fish-
ing effort,about 10 percent of the total angler days
in Alaska (Mills 1980).In 1981,over 102,240 angler
E-3-14
-
2.2 -Species Biology and Habitat Utilization
days were expended in the Susitna Basin~representing
about 7 percent of the total angler days in Alaska
(Mill s 1982).
The sport fish harvests for 1978 through 1981 from
the Susitna basin,based on mail ing surveys to a
sample of licenses,are shown in Table E.3.6 (Mills
1979,1980~1981,1982).
The figures represent the sport fishing harvest
throughout the Susitna basin and represent an area
that is larger than that which could be affected by
the proposed project (see Figures E.3.4 to E.3.6 for
locations of major tributaries listed in Table
E.3.6)•
The 1978 and 1981 estimated catch of arctic grayling
represents about 28 and 33 percent of the estimated
harvest in south-central Al aska and the estimated
catch of rainbow trout represented about 13 and 10
percent of the entire state harvest in 1978 and 1981,
respectively.The 1978 and 1981 Susitna harvest of
pi nk salmon represented about 39 and 13 percent of
the total estimated harvest for south-central Alaska;
the harvest of coho represented about 18 and 10 per-
cent;and the harvest of chinook represented about 11
and 19 percent.
.-
(i i )Subsistence Harvest
Al though sal mon form an important resource for many
Susitna basin residents,subsistence fishing within
the Susitna basin is an unquantified harvest.How-
ever,the Tyonek Village subsistence salmon fishery,
approximately 30 miles (50 km)southeast of the mouth
of the Susitna River,is supported primarily by
Susitna River stocks (see Chapter 5,Section
3.7.1[dJ).
2.2 -Species Biology and Habitat Utilization
in the Susitna River Drainage
2.2.1 -Species Biology
(a)Salmon
(i)Chinook
A generalized periodicity chart summarlzlng signifi-
cant chinook life stages in the Susitna River up-
stream from Talkeetna is illustrated in Figure
E.3.10.
E-3-15
2.2 -Species Biology and Habitat Utilization
-Upstream Migration of Returning Adults
In the Susitna River below Talkeetna,the adult
chinook salmon migration begins in late May and
ends in early to mid-July.Historically,by July
1,90 percent or more of the escapement have
migrated past the Susitna Station (ADF&G 1972).
Sonar counters and fishwheels installed in 1981 at
stations identified in Figures E.3.4 and E.3.5 to
monitor escapements for pink,chum,sockeye,and
coho salmon provided incidental information
regarding the timing of chinook runs.Fishwheel
catches indicate that the 1981 migration ended by
July 7 at the Yentna Station (AOF&G 1983).Initial
sonar counts made at Sunshine Station also sugges-
ted that a significant segment of the 1981 escape-
ment had migrated past thi s location pri or to the
June 23 sonar counter installation.
Similarly,a sizable portion of escapement had
al ready passed the Tal keetna site before June 23,
when the sonar counters became operational.Fi sh-
wheel catches and sonar counter data indicated that
the migration had passed Sunshine Station by
July 7 (ADF&G 1983).At Curry Station,the fish-
wheel s cl early defi ned the begi nni ng of the 1981
migration on June 16,the peak of migration on
June 23,and the end of migration on July 4.
In 1982,the chinook migration at Sunshine Station
began,reached a midpoint and ended June 18,
June 30,and July 9,respectively (ADF&G 1983).At
Talkeetna Station the 1982 chinook migration
covered the period June 11 to August 5 with over 80
percent of the run passing Talkeetna from June 21
to July 12.A simil ar pattern was observed at
Curry Station where 80 percent of the fishwheel
captures were recorded from June 21 to July 12
(ADF&G 1982e).Catches at Sunshine,Talkeetna and
Curry Stations peaked on June 30,July 3,and
July 1,respectively.
Radio telemetry studies during June,July,and
August of 1981 (ADF&G 1981b)indicated that the
confluence of the Talkeetna,Chulitna,and Susitna
fivers is a milling area for migrating adult
chinook salmon.The four fish tagged at the
Talkeetna site moved downstream and remained either
at the confluence or downstream from this area for
several days or weeks before moving back upstream.
E-3-16
-
-
2.2 -Species Biology and Habitat Utilization
Thi s downstream movement was seen in 2 of the 12
fish that were radio tagged at the Curry site.Ten
of the 12 fish tagged at the Curry Station site and
three and four fish tagged at the Talkeetna site
moved upstream,11 entering one tributary and two
into another.Of the three remaining fish,one
moved downstream and held near Chase Creek,and two
were lost because of technical difficulties with
the transmitters.
-Population Estimates
Popul ati on est imates for chi nook were cal cul ated
from tag/recapture data in 1982.Based on these
estimates,49,600 chinook reached Sunshine Station,
10~900 reached Talkeetna,and 11,300 reached Curry
(ADF&G 1983;Table E.3.5).
Age Composition
In 1981,four-year old individuals were dominant at
Sunshine and Curry Stations,while at Talkeetna,
six-and four-year olds were equally abundant.
There was a hi gher percentage of younger fish,
mainly three-year olds,at Sunshine Station than at
either the Ta 1keetna or Curry Stati ons.Seven-year
old fish were relatively scarce at Sunshine and
Talkeetna,and none were identified from the Curry
Station sample.
-Spawning Locations
Surveys of chinook salmon spawning areas were per-
formed by helicopter;single-engine,fixed-wing
aircraft;and by foot during the 1981 and 1982
investigations.Chinook appear to spawn in the
tributaries rather than the mainstem of the Susitna
Ri ver.Some of the more important spawni ng tri bu-
tari es i ncl ude Al exander Creek,Kroto Creek,
(Deshka River),Willow Creek,Clear Creek (in the
Talkeetna drainage),Chulitna River,Peters Creek,
Lake Creek,Talachulitna River,Prairie Creek,
Montana Creek,Indian River,and Portage Creek
(Tables E.3.7 and E.3.8,Figures E.3.4 to E.3.6).
During 1982,adult chinook entered Devil Canyon and
spawned at Cheechako Creek (RM 152.5)and an
unnamed creek (RM 156.8).Peak spawning ground
counts were 16 and 4 chinook at Cheechako Creek and
the unnamed creek,respectively (ADF&G 1982e).
E-3-17
2.2 -Species Biology and Habitat Utilization
-Incubation and Emergence
In the Susitna River system,chinook spawn in July
and early August (ADF&G 1981b).In Alaska,each
female deposits from 4200 to 13,000 eggs,which
incubate in the gravel through winter and hatch the
following spring (Morrow 1980).The alevins gen-
erally remain in the redd until the yolk sac is
absorbed and then emerge from the gravel and become
free-swimming,feeding fry (Morrow 1980).
-Juvenile Behavior
The chi nook fry school after emergi ng from the
gravel but become territorial as they grow.
Aquatic insect larvae,including chironomids and
caddis flies as well as small crustaceans,are the
major food sources for juvenile chinook salmon
(ADF&G 1978).Analysis of adult chinook salmon
scales shows that most Susitna River salmon remain
in freshwater for one year before smolting (ADF&G
1981b).
Juvenil e chi nook sal mon were captured throughout
the study area from Al exander Creek (RM 10.1)up-
stream to Portage Creek (RM 148.8).Collection
techniques and data summaries for juvenile collec-
tions are detailed in ADF&G (1981d).Populations
varied in abundance and distribution by river habi-
tat type and seasonal period.
During winter,most juveniles were captured at
mainstem and slough sites.All juvenile chinook
salmon captured at the mainstem and slough sites
are believed to have migrated from associated
streams,since no chinook salmon spawning has been
recorded in the mainstem or sloughs.The migration
to mainstel11 and slough sites during late fall is
apparently the result of icing and lowered flow in
tributaries (ADF&G 1981d).
During summer,juvenile chinook were also captured
throughout the study area below Devil Canyon from
Portage Creek to Al exander Creek.The reach be-
tween Devi 1 Canyon and Ta 1 keetna accounted for 34
percent of the total captu res,and the remai nder
were captured between Talkeetna and Cook Inlet
(ADF&G 1981b).Tributary mouths appear to provide
important rearing habitat during summer months.
E-3-18
"'""
....
2.2 -Species Biology and Habitat Utilization
Cl ear-water sloughs supply summer reari ng habitat
and may be important year-round rearing habitat.
During the 1981 field program,two age groups of
juvenile chinook salmon,representing brood years
1979 (l+J and 1980 (0+),were identified from scale
analysis and length distribution.Age 1+were
observed between Devil Canyon and Talkeetna at 45
percent of sites surveyed duri ng the fi rst two
weeks of June.Captures decreased and terminated
in July.Age 1+were not captured after August in
the Talkeetna to Cook Inlet reach.It was con-
cluded that the decreasing numbers of age 1+
chinook sal mon were a result of smol tout-migration
(ADF&G 1981d).The highest catches of juvenile
chinook in 1982 smolt trap samples from Talkeetna
Station was recorded between mid-June and mid-July,
but the trap may have been deployed after the peak
of out-migration (Table E.3.8).
Catches of age 0+in mainstem and slough habitats
increased from late June to a high in early
September for the Devil Canyon to Talkeetna reach.
This was interpreted as an indication that juvenile
di stri buti on expanded from tri butary streams and
stream mouth sites into mainstem and slough sites
as summer progressed (ADF&G 1981d).
Interpretat i on of present and past surveys of the
Susitna River and its tributaries have resulted in
the following conclusions relating to abundance,
distribution,and out-migration (ADF&G 1981d).
•Juvenile chinook salmon populations are not
static but vary in abundance and distribution by
season within the various river habitats;
•Redistribution of juvenile chinook from areas of
emergence (tributaries)to more favorable habitat
at the mouths of'tributaries and sloughs begins
as the fish reach a mobile state;
•Tri butary mouths appear to provi de important
mill ing and rearing areas for juveniles during
summer months;•
•During late fall,tributary discharge decreases
causing the juveniles to move into the mainstem
and slough habitats to overwinter;and
E-3-l9
2.2 -Species Biology and Habitat Utilization
•The majority of juvenile chinook spend one winter
in freshwater before mi grat i ng to the sea.Out-
migration in the reach from Devil Canyon to
Ta 1 keetna peaks pri or to ea rly June and termi-
nates by the end of July throughout the drai n-
age.
(i i)Sockeye
A generalized periodicity chart summarlzlng signifi-
cant sockeye life history stages in the Susitna River
upstream from Talkeetna is illustrated in Figure
E.3.10.
-Upstream Migration of Returning Adults
The escapement,migrational timing,and population
estimates of adult sockeye moving up the Susitna
River to spawning grounds were measured in 1981 and
1982 by side-scan sonar,fishwheel catches,and
tag/recapture studies.The five escapement moni-
toring stations were established in early June 1981
at locations identified in Figure E.3.4 to E.3.6.
Operating dates,equipment used,and methodology
are described in detail in ADF&G (l981b);results
are reported in ADF&G (1983).
•At Susitna Station,the 1981 sockeye salmon mi-
gration extended from July 4 to July 31 (ADF&G
1983).Because July 10 and July 23,75 percent
of the escapement passed Su s itna Stat i on.Fi sh-
wheel catch per hour indicated that the peak
migration occurred between July 10 and July 19.
In 1982,the migration began,reached midpoint
and ended July 18,July 25,and August 5,respec-
tively (ADF&G 1983).
At the Yentna Station,the migration began on
July 10,and the run ended by July 30.Between
July 12 and 23,75 percent of the total fish
escapement had passed Yentna Stati on.Fi shwheel
catches indicated that the migration peak was
between July 13 and 15.In 1982,the majority of
the migration passed Yenta Station between July
18 and August 6 (Figure E.3.11).
•At Sunshine Station,the 1981 migration began on
approximately July 16,and ended on August 26.
Between July 19 and 28,75 percent of the sockeye
£-3-20
-
-
-
2.2 -Species Biology and Habitat Utilization
migrated past this location.Based upon fish-
wheel catch records,the peak of the migration
occurred between July 18 and 23.The majority of
the 1982 sockeye mi grat i on passed Sunshi ne
Station between July 27 and August 18 (Figure
E.3.11).
•At Talkeetna Station,the 1981 migration com-
menced on July 23 and was completed by August 26.
A majority of the total count was made between
July 23 and August 6.It appeared from fishwheel
catch data that the migratio~peak occurred
between July 27 and August 1.The majority of
the 1982 migration passed Talkeetna Station
between July 27 and August 18 •
•At Curry Station,the 1981 migration commenced on
July 23,was over on August 22.In 1982,the
majority of the sockeye were counted between
July 27 and August 28 (ADF&G 1983).
From the sonar data,the 1981 migration chrono-
logy of sockeye salmon indicates that those fish
pass i ng Sus itna Stati on en route to the Yentna
River made the 6.2-mile (10-km)trip in one day
or less.Individuals migrating past Susitna
Station toward Sunshine Station covered this
distance in 1981 in an average of 8 days (6.8
miles per day,or 11 km per day),and reached
Talkeetna Station in an average time of 13 days
(4.6 mil es per day,or 7.7 km per day).Tag/
recapture data indicated that the mean travel
rate between Sunshine and Talkeetna Stations and
Curry Station in 1981 was between 3.0 and 4.4
miles per day (5.0 and 7.7 km per day)(Table
E.3.10).In 1982,the mean travel rate was
between 2.7 and 3.4 miles per day (4.5 and 5.7 km
per day).
Population Estimates
Population estimates were calculated based upon
tagging operations at Sunshine,Talkeetna,and
Curry Stations and upon side-scan sonar counts at
Yentna Station.Sockeye estimates indicated that
approximately 139,000 sockeye migrated past Yentna
Station,133,000 migrated past Sunshine,4800 past
Talkeetna,and 2800 past Curry Station in 1981.In
1982 the val ues were 114,000,151,000,3100,and
E-3-21
2.2 -Species Biology and Habitat Utilization
1300 past the same stations,respectively (Table
E.3.5)•The 95 percent confidence 1 imits on the
Petersen popul ati on estimates and components used
to calculate them are discussed in ADF&G (l981b,
1983).
The Susitna River drainage escapement can be
approximated by the summation of Yentna River and
Sunshi ne Stat i on escapement estimates •The result
is an underestimate,however,because the escape-
ment estimates do not include escapements to other
tri butari es downstream from RM 77.Us i ng these
estimates,the minimum sockeye escapement to the
Susitna Ri ver was 272,000 in 1981 and 265,000 in
1982 (ADF&G 1983).
-Age Composition
Sockeye salmon age composition analyses in 1981
indicate that a majority of the fish sampled at
each station were age 52'(i.e.five years old
wi th two years in freshwater).The second most
abundant age group was 42 fol lowed by age 62.
Five-year-old fish comprised approximately 86 per-
cent of the return at Susitna and Yentna Stations,
73 percent at Sunshine and Talkeetna Stations,and
70 percent at Curry Station (ADF&G 1981a).Further
age composition data are given in Table E.3.11.
-Spawning Locations
Surveys of sockeye spawning areas in 1981 and 1982
were conducted in the mainstem Susitna River be-
tween Devil Canyon and Cook In1 et from 1 ate July
through September using drift gill nets,e1ectro-
shocking equipment,and egg deposition pumps.
Susitna River tributary streams and sloughs between
Devil Canyon and the Talkeetna River confluence
were surveyed on foot for spawning salmon from late
July through September.The detai led methodology
used is given in ADF&G (1981b and 1983).No main-
stem spawning was observed for sockeye salmon.In
the Devil Canyon to Talkeetna reach,adult sockeye
were observed in 12 of the 33 sloughs surveyed and
in Lower McKenzie Creek in 1981;while in 1982,
spawning sockeye were observed in 10 of 34 sloughs
and Portage Creek (Fi gures E.3.12 -E.3.17)•Peak
spawni ng occurred duri ng the 1ast week of August
E-3-22
2.2 -Species Biology and Habitat Utilization
and the fi rst three weeks of September.Of the
locations listed,sockeye were most numerous in
Sloughs 8A,9B,11,and 21.
-Utilization of Spawning Habitat
The weekly counts of spawning sockeye obtained by
ADF&G in 1981 and 1982 for the sloughs upstream
from Talkeetna (ADF&G 1981a and 1983)were
converted to estimates of the total number of
spawning sockeye in each slough.The counts were
converted to estimated total numbers using the
estimating technique described in Bell (1980),
i.e.,the counts are plotted by day,the area under
the resulting curve is calculated and divided by
the estimated average stream life of the spawning
fish.The sockeye stream life was assumed to be 12
days,based on estimates derived for the
Chakachamna system on the west side of Cook Inlet
(Bechtel Civil and Minerals,Inc.1983).The
est i mated numbers of spawni ng sockeye us i ng each
slough in 1981 and 1982 are presented in Table
E.3.12.The total number of sockeye est i mated to
have spawned in sloughs during 1981 and 1982 was
2315 and 1402.
The 1981 and 1982 total estimates for slough spawn-
i ng sockeye are 83 and 108 percent of the Peteren
popu1 at i on estimates of sockeye pass i ng the Curry
fi shwhee 1 stat ion in the res pect i ve years.These
high percentages,combined with the lack of spawn-
ing sockeye in mainstem and tributary spawning
areas,indicate that sockeye spawning is confined
to sloughs upstream from Talkeetna.Over 98
percent of the sockeye spawning in sloughs in 1981
and 1982 spawned in 11 sloughs:8A,8B,8C,Moose,
B,9,9A,96,11,17,and 21 (Figures E.3.12 to
E.3.17;Table E.3.12).If it is assumed that there
was a 1:1.3 ratio to female sex ratio in 1981 and
1.5:1 ratio in 1982 (ADF&G 1983)and that sockeye
require 72 square feet of spawning habitat per redd
(Foerster 1968,Bell 1980),then the 1981 spawning
sockeye used 2.2 acres {0.9 ha}and 1982 spawning
sockeye used 0.9 acres (0.4 ha)of slough spawning
habitat..
Scale patterns of sockeye returning to Chulitna and
Talkeetna River spawning areas and of sockeye
spawning in sloughs upstream from Talkeetna were
examined as part of the ADF&G stock separation
E-3-23
2.2 -Species Biology and Habitat Utilization
program.The analysis indicated that the sockeye
spawning in sloughs upstream from Talkeetna in 1982
were not a separate stock,but were strays from
Chulitna River and Talkeetna River stocks.
-Incubation and Emergence
Based upon information from other sockeye-producing
spawning areas,mature females typically produce
from 2500 to 4300 eggs (Morrow 1980).Hatching
normally occurs duri ng the peri od January-March.
Fry remain in the gravel until emerging from April
through June.In most systems,fry move into lakes
or other rearing areas after emerging from the
gravel and spend 1 to 3 years in freshwater before
migrating to feeding grounds in the Pacific Ocean
(Morrow 1980).In the Devil Canyon to Talkeetna
reach,however,there are no lakes for sockeye
rearing,and sockeye fry originating in the sloughs
appear to leave this reach during the first summer
(Table E.3.9)(ADF&G 1981d,1982f).
-Juvenile Behavior
Results of the 1982 smolt trappi ng program indi-
cate that age -0 sockeye leave the Devil Canyon to
Talkeetna reach in June and July (Table E.3.9).
The peak of out-migration appears to occur in the
first two weeks of July.There was a gradual
decline in catch rate from August through
September.
(iii)Coho
A generalized periodicity chart summarlzlng signifi-
cant coho 1 ife history stages in the Susitna River
upsteam from Talkeetna is illustrated in Figure
E.3.10.
-Upstream Migration of Returning Adults
The escapement,migrational timing,and population
estimates of adul t coho sal mon mi grat i ng up the
Sus itna Ri ver to spawni ng grounds were determi ned
from results of apportioned,side-scan sonar
counts,fishwheel catches,and tag/recapture esti-
mates (ADF&G 1981b and 1983).
E-3-24
(::""C"7",
-
-
2.2 -Species Biology and Habitat Utilization
The peak of the coho salmon migration into the
Susitna Ri ver drainage occurs in mid-July and early
August,but can extend from 1ate June into
September.Migration periods for each sampling
station are summarized below.
At the Susitna Station in 1981,the migration
began on July 23 and ended August 9.Approxi-
mately 75 percent of the fish passed this station
between July 23 and August 16.Fishwheel catches
indicated a migration peak occurring between
July 25 and July 30.During 1982,the majority
of the run passed Susitna Station between July 19
and August 9 (Figure E.3.19).
•At the Yentna Station in 1981,the migration
began on Jul y 22 and ended on August 17.The
major portion of the run passed this location
between July 23 and August 16.The peak of
migration occurred between July 23 and August 6.
During the 1982 migration,the majority of the
coho passed Yentna Station between July 20 and
August 24.
•At the Sunshine Station,the beginning of the
1981 migration was August 1,and the run ended on
August 3.Between August 4 and August 24,75
percent of the migration run occurred.The peak
migration period was between August 18 and August
25.In 1982,the majority of the coho passed
Sunshine Station between August 3 and August 23
(Fi gu re E.3.19)•
•At the Talkeetna,the beginning of the 1981
migration was August 6,and September 1 was the
termination.The majority of coho were counted
between August 11 and September 1.The mi gra-
tional peak period occurred between August 19 and
August 30.In 1982,the coho passed Talkeetna
Station primarily between August 5 and
Se ptembe r 2.
•Curry Station fishwheel catches indicated that
the 1981 coho migration began at this location on
August 5 and ended on September 4.Duri ng 1982,
the Curry fishwheels caught coho from August 2 to
September 11 (ADF&G 1982e).
E-3-25
2.2 -Species Biology and Habitat Utilization
In 1981,the average travel time for coho salmon
migrating between Susitna Station and Yentna
Station was two days,a travel rate of approximate-
ly 3.1 miles (5 km)per day.In 1981,coho had a
migration rate of 3.9 miles (6.5 km)per day from
Susitna Station to Sunshine Station and 4.0 miles
(7 km)per day between Sunshine and Talkeetna
Stations.In 1982,the mean rate between Sunshine
and Talkeetna was 5.3 miles (8.5 km)per day.
Tag/recapture of marked coho indicated that between
Talkeetna and Curry Stations the mean travel rate
in 1981 was approximately 11.3 miles (18.8 km)per
day,while in 1982 the mean rate was 10.0 miles (16
km)per day (Table E.3.10)(ADF&G 1983).
-Population Estimates
Population estimates derived from tagging and re-
capture operations at Sunshine Station,Talkeetna,
and Curry stations and sonar counts at Yentna
Station indicated that approximately 17,000 coho
migrated past Yentna Station,19,800 migrated past
Sunshine Stations 3300 past Talkeetna Station and
1100 past Curry Station in 1981,while 34,100,
45,700,5100,and 2400 passed the same stations in
1982 (Table E.3.5).
The Susitna River drainage estimated escapement of
coho,deri ved by summi ng the Yentna Station and
Sunshine Station estimates,was 36,000 in 1981 and
79,800 in 1982.This estimate does not include
coho migrating to tributaries downstream from RM
77,except for the Yentna River (ADF&G 1983).
-Age Composition
The majority of individuals sampled for age
analyses in 1981 were 42 from the 1977 brood
year,followed by'age 32 from the 1978 brood
yea r.Less than 10 percent of the 1981 coho es':"
capement consisted of other age groups (ADF&G
1981a)•
-Spawning Locations
Surveys of spawni ng areas were conducted in the
mainstem,sloughs,and tributaries of the Susitna
E-3-26
.....
-
.-,
2.2 -Species Biology and Habitat Utilization
River (ADF&G 1981b).Of 12 mainstem spawning sites
identified in 1981,coho salmon were the only
species observed at 1 site,and at 2 other mainstem
sites coho and chum salmon shared the spawning
sites.In 1982,4 of 11 mainstem spawning sites
between Devil Canyon and Talkeetna contained coho,
and all 4 were shared with chum salmon (Table
E.3.13).Coho salmon were not observed spawning in
any sloughs during 1981.In 1982,coho were ob-
served in3 sloughs but actually spawned in only 1,
Slough 8A (Figures E.3.12 to E.3.17,ADF&G 1983).
Spawning coho were observed in 8 of 15 creeks sur-
veyed between Devil Canyon and T~lkeetna in 1981
and 12 of 19 creeks surveyed in 1982 (ADF&G 1981a,
1982e).The survey data indicate that the spawning
peak occurred in the second and thi rd weeks of
September.
-Incubation and Emergence
Based upon information on coho salmon life history
in Alaska (Hartman 1971),each female deposits an
average of 3500 eggs,which incubate in the gravel
through winter.Upon emergence in March and April,
fry generally occupy areas with adequate cover,
low-water vel ociti es,and moderate water tempera-
ture for optimum growth (Gray et a1.1978;Delaney
and Wadman 1979;Watsjo1d and Engel 1978).Drift-
ing aquatic insect larvae are the major diet items
of juvenile coho salmon in spring;adult stages of
these insects a re major feed items duri ng summer
and fall (ADF&G 1978).Juvenile pink,chum,and
sockeye salmon can also be an important supple-
mental food source to age 1 or 01 der coho sal mon
(Roos 1960;Scott and Crossman 1973).
-Juvenile Behavior
The geographical and seasonal distribution,rela-
tive abundance,age composition,and smolt migra-
tion timing of coho salmon reared in the Susitna
drainage are summarized below based on studies by
ADF&G (1981d).
Juvenil e coho salmon were captured throughout the
study area between Alexander Creek (RM 10.1)and
Slough 21 (RM 141.8)at 55 of the 99 sample sites
sampl ed between November 1980 and October 1981.
Collection techniques and data summaries for juve-
nile collections are detailed in ADF&G (1981d).
E-3-27
2.2 -Species Biology and Habitat Utilization
During the winter and spring (November-May),juve-
nile coho salmon most frequently occurred at tribu-
tary mouth sites between Talkeetna and Cook Inlet,
and at mainstem and slough sites between Devil
Canyon and Talkeetna (Table E.3.13).During June-
September 1981,j uveni 1e coho salmon occurred most
frequently at tributary mouths in the Talkeetna to
Cook Inlet reach (Table E.3.14).
During June-September 1981,juvenile coho salmon
occurred most frequently at tributary mouths in the
Talkeetna to Cook Inlet reach (Table E.3.15).
Three age groups of juvenile coho salmon as indi-
cated by 1ength frequency and scale anal ys is were
collected at various habitat locations in the Devil
Canyon to Cook Inl et reaches of the Susitna River
from November 1980 to October 1981.These fi sh
represented brood years 1978 (2+),1979 (1+),and
1980 (0+).Distribution of 0+fish progressively
increased from June when they were fi rst captured,
through September.Occurrence was consistently
higher at tributary mouth locations than at main-
stem or slough locations throughout the summer.
The frequency of occurrence in tri butary mouths
increased duri ng the summer i nd i cat i ng that age 0
coho were moving out of the tributaries.The inci-
dence of 1+coho salmon in catches of all habitat
locations between Devil Canyon and Talkeetna also
increased from 1ate July to September.Between
Talkeetna and Cook Inlet,a similar pattern was
observed.Catch rates then decreased in late
September for 0+and 1+throughout the Devil Canyon
to Cook Inlet reach (ADF&G 1981b).
Age 2+individuals were captured during the winter
sampling period,November 1980 to May 1981,but
were not captured after May in the Devil Canyon to
Talkeetna reach and after mid-June in the Talkeetna
to Cook Inlet reach.This finding indicates that
the predominate age group for smolts in the Susitna
River is age 2+and that in the Devi 1 Canyon to
Talkeetna reach the majority of smolting took place
prior to June 1,1981 and between Tal keetna to
Cook Inlet by June 15.The 1982 smo It trappi ng
program at Talkeetna further supports this finding.
Peak catches of juvenile coho were recorded shortly
after the trap was set in mid-June,and catches
declined rapidly thereafter (Table E.3.9).If the
peak outmigration occurred in early June,the trap-
ping program caught the end of the migration.
E-3-28
2.2 -Species Biology and Habitat Utilization
(i v)Chum
I"""
!A generalized periodicity chart summarlzlng signifi-
cant chum 1 ife hi story stages in the Susitna Ri ver
upstream from Talkeetna is illustrated in Figure
E.3.10.
-Upstream Migration of Returning Adults
-
-
.....
I
-
The escapement,migrational timing,and population
estimates of adult chum salmon migrating up the
Susitna River to spawning grounds were measured by
side-scan sonar and fi shwheel catches in combi na-
tion with tag/recapture estimates (ADF&G 1983).
Apportioned sonar counts andfishwheel catches show
that the chum salmon migration began during the
second week in July and ended during early Septem-
ber.The peak migration period in the Susitna
River upstream from Talkeetna was from late July
until late August •
•At Susitna Station,the 1981 migration began on
July 10 and ended on August 25.Between July 15
and August 7,75 percent of the escapement
occurred.Fi shwheel catches indi cated that the
mi g rat i on peak occurred between August 3 and 7.
In 1982,the majority of the chum migration
passed Susitna Stat ion between July 19 and
August 10 •
The 1981 migration began at Yentna Station on
July 18,and ended on August 21.A majority of
the fish were counted between July 18 and August
15.Fishwheels operated at Yentna Station indi-
cated that the mi g rat i on run reached its peak
July 23.In 1982,the majority of the run passed
Yentna Station between July 20 and August 18
(Figure E.3.18).
At the Sunshine Station the 1981 migration com-
menced on July 26,and ended on approximately
August 5.Seventy-five percent of the fish were
counted between July 27 and August 24.The peak
of chum migration at Sunshine Station,as indi-
cated by fi shwhee 1 catches,occur red on
August 19.In 1982,the chum migration passed
Sunshine Station primarily between July 29 and
August 21.
E-3-29
2.2 -Species Biology and Habitat Utilization
•At Talkeetna Station,the beginning of the 1981
migration was approximately July 28,and the mi-
gration ended on September 4.In 1982,the chum
migration passed Talkeetna Station between
August 2 and August 22 (Figure E.3.18)•
•Fishwheel catches at Curry Station indicated that
the chum migration began around August 5,and the
mi grat ion termi nated on September 2.In 1982,
the majority of the chum were caught between
August 3 and August 26 (ADF&G 1983).
In 1981,chum salmon averaged 4 days travel time
betweenSusitna Station and Yentna Station,which
corresponds to a travel rate of 1.6 mil es
(2.7 km)per day.Average travel time between
Susitna Station and Sunshine Station was 10 days,
a travel rate of 5.6 miles (9.3 km)per day.The
migration period between Susitna Station and
Talkeetna Station averaged 14 days or approxi-
mately 5.6 mil es (9.3 km)per day.Chum sal mon
tagged at Sunshine Station in 1981 took between 2
and 9 days to reach Ta"lkeetna Station,with a
mean travel rate of 4.6 miles (7.7 km)per day
(Table E.3.10).Between Talkeetna Station and
Curry Station the number of travel days in 1981
ranged from 1 to 24 days with a mean travel rate
of approximately 3.8 miles (6.3 km)per day.In
1982,the mean travel rate of tagged chum was 7.4
miles (12.3 km)per day between Sunshine and
Talkeetna and 6.5 miles (10.9 km)per day between
Talkeetna and Curry (Table E.3.10)(AOF&G 1983).
-Population Estimates
Population estimates derived from tag and recapture
data at Sunshine,Talkeetna,and Curry Stations and
sonar counts at Yentna Station indicated that
approximately 19,800 chum migrated past Yentna
Station,263,000 migrated past Sunshine,20,800
passed Talkeetna Station and 13,100 past Curry Sta-
tion in 1981,while 27,800,430,000,49,100,and
29,400 passed the same stations in 1982 (Table
E.3.5).
The Susitna River drainage estimated escapement of
chum,deri ved by summi ng the Yentna Station and
Sunshine Station estimates,was 283,000 in 1981 and
458,000 in 1982.Th is est i mate does not include
chum migrating to tributaries downstream from RM
77,except for the Yentna Ri ver (ADF&G 1983).
E-3-30
.F"
i
2.2 -Species Biology and Habitat Utilization
-Age Composition
At each samp 1i ng site,age 4 c hum salmon from the
1977 brood year dominated the catch in 1981,com-
prising,on the average,86 percent of the sample.
Second in abundance were age 5 fish,followed by
age 3 individuals (ADF&G 1981a).
-Spawning Locations
Spawning surveys conducted in the mainstem of the
Sus itna River from Devil Canyon to Cook Inlet
revealed that 10 of 12 mainstem spawning locations
identified in 1981 were occupied by chum salmon,
while 10 of 11 mainstem spawning locations identi-
fi ed between Devi 1 Ca nyon and Ta 1keetna in 1982
were utilized by chum salmon (Table E.3.13).
Spawning surveys conducted in sloughs and tribu-
taries between Devil Canyon and Talkeetna docu-
mented the presence of chum salmon in 20 of the 33
sloughs surveyed in 1981 and 17 of the 34 sloughs
surveyed in 1982 (Figures E.3.12 to E.3.17).
Spawni ng chum were al so found withi n the survey
reaches of 8 of 15 tributaries surveyed in 1981 and
8 of 19 tributaries surveyed in 1982 between Devil
Canyon and Ta"lkeetna.The peak spawning activity
in the sloughs occurred duri ng the 1ast two weeks
of August and the fi rst two weeks of September.
Based on the stream survey data,the peak spawning
period was approximately one week earlier in
streams than in slough spawning areas.
-Utilization of Spawning Habitat
The weekly counts of spawning chum salmon obtained
by ADF&G in 1981 and 1982 for the sloughs upstream
from Talkeetna (ADF&G 1981a and 1983)were conver-
ted to an e§timate of the total number of spawning
chum in each slough using the technique described
for sockeye'salmon.For ~hum,the stream life was
assumed to be 10 days,based on estimates derived
for the Chakachamna system (Bechtel Civil and
M"ineral s,Inc.1983).The estimated numbers of
spawning chum using each slough in 1981 and 1982
are presented in Table E.3.12.The tDtal number of
chum estimated to have spawned in sloughs upstream
from Talkeetna during 1981 and 1982 was 3526 and
3674.
E-3-31
2.2 -Species Biology and Habitat Utilization
The 1981 and 1982 estimates of the total number of
chum spawning in sloughs upstream from Tal keetna
are 27 and 12 percent of the Petersen population
estimate for chum passing the Curry fishwhee1
station.The remainder primarily spawned in tribu-
taries,with some also spawning in the mainstem
(Figures E.3.12 to Eo3.17 and Tab1 e E.3.13).Over
97 percent of the chum spawning in sloughs in 1981
and 1982 spawned in 13 sloughs:8,8A,8B,8C,
Moose,A',B,9,9A,9B,11,17,and 21.If it is
assumed that the sex ratio was 1:1 (ADF&G 1983i and
that chum salmon need 81 square feet (7.3 m)of
spawning habitat per redd (Hale 1981),chum used
3.3 acres (1.3 ha)and the 1982 chum used 3.4 acres
(1.4 ha)of slough spawning habitat.
-Incubation and Emergence
Based on information from other chum salmon-produc-
ing areas in Alaska,females produce an average of
3000 eggs (Hartman 1971).Limited sampling of pre-
emergent chum fry conducted April 11,1981 near
Gold Creek (RM 136.8)revealed that yolk sac ab-
sorption was 95 to 100 percent complete.Following
emergence,usually during April or May,chum fry
remain in the river for only a short period before
out-migrating.Limited beach seine sampling resul-
ted in the capture of 1650 chum fry on June·19,
1981 in Slough 11.
-Juvenile Behavior
In 1982,a smo1t trap was utilized at Talkeetna to
evaluate the timing of downstream smolt migrations.
The trap was monitored from June 18 through October
12.Peak catches of chum fry were recorded duri ng
the first week of sampling (Table E.3.9);thus,it
is possible that out-migration peaked prior to the
June 18 sampling effort.
(v)Pink
A generalized periodicity chart SUmmarlZlng pink
salmon life history stages in the Susitna River is
illustrated in Figure E.3.10.
-Upstream Migration of Returning Adults
Pi nk salmon have a 2-year 1 ife cycl e that results
in two genetically distinct stocks occurring in
E-3-32
r""'--',
r
.1
.-
-/
.-
2.2 -Species Biology and Habitat Utilization
each stream.The stocks are called "o dd_"or
"even-year"on the basis of the year in which
adults spawn.In the Susitna drainage.the even
year runs are numerically dominant.The escapement
migrational timing and population estimates of pink
salmon migrating up the Susitna Ri ver to spawning
grounds was measured by side-scan sonar and
tag/recapture (ADF&G 1983).
•At Susitna Station,the 1981 migration period
started around July 10 and the migration termi-
nated on August 21.Seventy-fi ve percent of the
escapement passed this station between July 15
and August 3.Fishwheel catches indicated that
the migration peak occurred between July 21 and
August 3.In 1982,the majority of the pink sal-
mon passed Susitna Station between July 21 and
August 5 (Figure E.3.20).
•At the Yentna Station the 1981 migration began on
approximately July 10 and ended on August 24.
The majority of the pink salmon passed this sta-
tion between July 21 and August 6.Fishwheel
catches indicated that the migration peak
occurred on July 30.The 1982 pink migration
primari ly passed Yentna Station between July 23
and August 7.
•The 1981 migration reached Sunshine Station on
approximately July 26,two weeks later than
Susitna Station,and was completed on August 14.
Seventy-five percent of the migration was counted
between July 28 and August 9.Fi shwheel catches
showed the migration peak to have occurred
August 1.The maj ority of the 1982 mi grat ion
passed Sunshin.e Station between July 29 and
August 3 (Figure E.3.20).
•The 1981 migration period at Talkeetna Station
was similar to that at Sunshine Station:the
migration reached Talkeetna on July 29,and ended
on August 20.Seventy-fi ve percent of the es-
capement passed Talkeetna Station between July 29
and August 10.Peak fi shwheel catches occurred
between August 1 and 10.In 1982,the majority
of the pink salmon passed Talkeetna Station
between August 12 and August 13.
•At Curry Station,the 1981 pink migration began
on July 30 and terminated approximately August
E-3-33
2.2 -Species Biology and Habitat Utilization
21.Between August 4 and 19,75 percent of the
escapement passed Curry Station.In 1982,the
pink salmon run passed Curry Station between
August 2 and August 13 (ADF&G 1983).
The migrational rates based on sonar and fish-
wheel catch data indicate that pink salmon took
an average of three days to reach Yentna Station
from Susitna Station,a distance of approximately.
6.2 miles (10 km).This represents an average
travel speed of approximately 1.9 miles (3 km)
per day.Between Susitna Station and Sunshine
Station,the ~verage travel time was 9 days with
a travel rate of 6.2 miles (10 km)per day.
Travel time between Sunshine and Tal keetna Sta-
tions averaged 2.6 miles (4.3 km)per day.Tag
and recapture data on pink salmon indicate that
travel time between Sunshine and Talkeetna Sta-
t ion in 1981 ranged from 2 to 30 days.In 1981,
pink salmon averaged three days of travel time or
6.0 miles (9.9 km)per day between Talkeetna and
Curry Station (Table E.3.10).In 1982,the mean
travel time for tagged pink salmon was 7.4 miles
(12.3 km)per day between Sunshine and Talkeetna
and 10.0 miles (16.7 km)per day between
Talkeetna and Curry (Table E.3.10)(ADF&G 1983).
-Population Estimates
Population estimates derived from tag and recap-
ture data at Sunshine,Talkeetna,and Curry Sta-
tions and sonar counts at Yentna Station indicate
that approximately 36,100 pink salmon migrated
past Yentna Station,49,500 pink salmon passed
Sunshine Station,2,300 passed Talkeetna Station,
and 1,000 passed Curry Station in 1981,while
447,000,443,000,73,000,and 59,000 passed the
same stations in 1982 (Table E.3.5).
The Susitna River drainage estimated escapement
of pink salmon,derived by summing the Yentna
Station and Sunshine Station estimates,was
85,600 in 1981 and 890,000 in 1982.This esti-
mate does not include pink salmon migrating to
tributaries downstream from RM 77,except for the
Yentna River (ADF&G 1983).
-Spawning Locations
Spawning surveys revealed that few pink salmon
spawn in mainstem habitats.During 1981,no
E-3-34
-
-
-
-!
2.2 -Species Biology and Habitat Utilization
mainstem spawning areas were found,while in 1982
two.mai nstem spawni ng areas were found betwe.en
Devil Canyon and Talkeetna (Table E.3.12).In
1981,3 of the 33 surveyed sloughs contained
spawning pink salmon while in 1982,10 of 34 sur-
veyed sloughs between Devil Canyon and Talkeetna
supported spawning pink salmon (Figures E.3.12 to
E.3.17,ADF&G 1983).Most pink salmon spawned in
tributary habitats,with 9 of the 15 tributaries
surveyed in 1981 and 14 of 19 tributaries sur-
veyed in 1982 containing spawning pink salmon
(ADF &G 1981a,1982e).
-Utilization of Spawning Habitat
The weekly counts of spawning pink salmon obtained
by ADF&G in 1981 and 1982 for the sloughs upstream
from Talkeetna (ADF&G 1981a and 1983)were conver-
ted to an esti mate of the total number of spri ng
pink salmon in each slough using the technique
described for sockeye salmon.The stream life was
assumed to be 7 days,based on estimates derived
for the Chakachamma system (Bechtel Civil and
Minerals,Inc.1983).The estimated numbers of
spawning pinks using each slough in 1981 and 1982
are presented in Table E.3.12.The total number of
pinks estimated to have spawned in sloughs upstream
from Tal keetna duri ng 1981 and 1982 was 28 and
735.
The 1981 and 1982 estimates of the total number of
pink salmon spawning in sloughs upstream from
Talkeetna represent 2.8 and 1.2 percent of the
Petersen population estimate for pink salmon'pas-
sing the Curry fishwheel station.Most pink salmon
were found to spawn in tributaries (Figures E.3.12
to E.3.17).
If it is assumed that the sex ratio was 1:1 and
that pink salmon need 6.3 square feet (0.6 m2)of
s pawni ng hab itat per redd (Be 11 1980),then the
1981 spawning pinks used 90 square feet (8.1 m2 )
and th 2 1982 pi nks used 2313 square feet
(208.2 m )of slough spawning habitat.
-Incubation and Emergence
Based on general information from other pink
salmon-producing areas in Alaska,female pink
E-3-35
2.2 -Species Biology and Habitat Utilization
salmon produce an average of about 2000 eggs
(Bailey 1969).Eggs hatch in mid-winter about 3 to
5 months after they are spawned,but fry remain in
the gravel until April or May.Spawning and time
of fry emergence are related to temperature regimes
of the streams (Bailey 1969).Pink salmon fry are
about 1 inch (2.5 cm)long when they emerge and
migrate directly to the sea.Limited information
obtained in spring 1981 for the Susitna drainage
indicates that sac fry of pink salmon appeared on
March 23 in Slough 11 and Indian River and yolk sac
absorption for pink fry was approximately 50 per-
cent on April 11 (ADF&G 1981d).
(b)Other Anadromous Species
(i)Beri ng Ci sco
The Bering cisco is a coregonid (i.e.,whitefish)
that occurs from the Beaufort Sea to Cook Inlet.
Although Bering cisco have been collected from upper
Cook Inlet and the Kni k Arm,the species was not
known to inhabit the Susitna River drainage prior to
1980-1981 ADF&G studies.Interior and western
Alaskan populations appear to contain both anadromous
and freshwater resident forms.Susitna River Bering
cisco appear to be anadromous (ADF&G 1981e).
Bering cisco were collected in the lower Susitna
River between RM 70 and RM 98.5 in 1981 and 1982,
respectively (AOF&G 1983).In 1981,the migration
began in August at Susitna Station (RM 26)and on
September 8 at Sunshi ne Station (RM 80).At
Sunshine,the 1981 fishwheel catches peaked on
September 21.In 1982,the migration began on August
7 at Susitna Station and on September 4 at Sunshine
Station.The 1982 fishwheel catches peaked on
September 27.
During 1981,spawning concentrations were identified
at RM 78 -79,76 -77.5 and 75.In 1982,spawni ng
was confirmed at RM 76.8 -77.6 and 81.2 (ADF&G
1983).It is suspected that spawni ng may occur
throughout the reach between RM 30 and RM 100 (ADF&G
1981e).Spawni ng substrates were composed primarily
of 1-to 3-inch (2.5-to 7.5-cm)gravel.Peak spawn-
i ng occurred duri ng the second week of October in
both 1981 and 1982 (ADF&G 1983).Susitna River
Bering cisco appear to occupy their spawning grounds
15 to 20 days.After spawning,these fish probably
rapidly migrate downstream to sea (ADF&G 1981e).
E-3-36
-
2.2-Species Biology and Habitat Utilization
(i i)Eul achon
The eul achon is an anadromous member of the smelt
family that spends most of its 1i fe in the mari ne en-
vironment.Adults are bel ieved to live at moderate
ocean depths in the vicinity of the echo-scattering
layer and in close proximity to shore.In the north-
ern portion of its range,eul achon spawn in May and
June.
During 1982,the spawning migration appeared to be
composed of two segments:an early run that started
prior to May 16 and ended about May 31,and a late
run that started about June 1 and ended about June 10
(ADF&G 1983).The second run was approximately 4.5
times larger in numbers than the first run.Eulachon
are known to util ize the Susitna River system at
1 east as far upstream as RM 58 in 1981 and RM 48 in
1982 (ADF &G 1982d).
In 1982,eulachon spawned in riffle areas and off-
shore of cut banks on unconsol i dated sands and gra-
vel s.Spawni ng occurred at water temperatures be-
tween 37.4 to 49.1°F (3.0 to 9.5°C)(ADF&G 1983).
(c)Resident Species
-
(i)Dolly Varden Char
Dolly Varden char are an important sport fish and are
distributed throughout Alaska where the species occu-
py aquatic habitats ranging from coastal streams to
lakes and streams located far inland.Dolly Varden
occur in Al aska in both anadromous and freshwater
resident forms.However,indications are that in the
Susitna drai nage,Dolly Varden are not anadromous.
Dolly Varden reach sexual maturity at age 4 to age 7
and normally spawn in clear-water streams during the
fall.
Two Dolly Varden were taken in the Devi 1 Canyon to
Cook Inlet reaches from November,1980 through May
1981.From June through September 1981,the catch of
Dolly Varden increased.Catches of Dolly Varden
peaked in June and 1ate September;1argest catches
per unit effort were recorded at the mouths of tribu-
tary st reams.Hi gher catches duri ng 1ate June and
July coincided with peak migration periods of pink,
chum,and sockeye salmon;higher catches during
E-3-37
2.2 -Species Biology and Habitat Utilization
September can be attributed to Dolly Varden moving
into their spawning areas within clear-water tribu-
taries and the beginning of out-migration into their
wintering habitat.Sexually mature fish were found
in September and October,and Dolly Varden displaying
spawning behavior were observed on October 2 in Upper
Indian River (ADF&G 1981e).
(ii)Rainbow Trout
Rainbow trout are one of the most valued sport fishes
in North Ameri ca.Susitna Ri ver sport harvest and
effort level s have steadily increased over the past
five years.The general life history is discussed by
Morrow (1980)and Scott and Crossman (1975).
Low numbers of rainbow trout were collected through-
out the winter months (November-May 1981)from RM 10
to RM 133 at seven tri butary and four mai nstem loca-
tions.During summer (June-September 1981),rainbow
trout were captured from RM 10 to RM 148 near Portage
Creek but not in the impoundment reach.Portage
Creek represents-one of the northernmost boundari es
of the native range for rainbow trout in North
America.The most consistent catches were associated
with tributary mouths and sloughs between Devil
Canyon and Talkeetna.Age groups 2,4,and 5 made up
a majority of the fish collected (ADF&G 1981e).
Catches peaked in 1 ate June between Devi 1 Canyon
and Talkeetna and again during the first two weeks of
September throughout the drainage.The June peak was
probably the result of the presence and movements of
spawni ng fi sh,whi 1 e the hi gh in September probably
reflected movement downstream into winter habitat
(ADF&G 1981e).
(iii)Arctic Grayling
The arctic grayling is also one of the most important
sport fi shes of Al aska and northern Canada and con-
tributes substantially to the sport fishery of the
Susitna River and its tributaries.Grayling are gen-
erally residents of clear,cold streams and lakes
(Scott and Crossman 1973).
Silt-laden glacial systems,such as the Susitna
River,are believed to support relatively few gray-
ling;however,such systems may provide essential
migratory channels and over-wintering habitat (ADF&G
E-3-38
.-
I
-
-
-
.....,
2.2 -Species Biology and Habitat Utilization
1981e).The arctic grayling is characterized by Reed
(1964)as a migratory species.During spring breakup
from April to June,adults migrate from ice-covered
1 akes and 1arge ri vers into cl ear,gravel bottomed
tributaries to spawn (Morrow 1980).In Alaska,
arctic grayling reach sexual maturity at age 2 to 7
years and are capable of spawning several times dur-
ing their lifetime.After spawning,the adults move
from the spawni ng areas to spend the rest of the
summer feeding on aquatic and terrestrial insects
taken from the aquatic drift (Vascotto 1970).A
downstream mi grat i on back to overwi nteri ng areas in
large rivers and deep lakes occurs in late August to
mid-September (Pearse 1974).
Duri ng 1980-81 ADF&G studi es,grayl i ng were captured
between Alexander Creek (RM 10.1)and the upper
reaches of the impoundment area.Catches were low
throughout wi nter months,but increased sharply in
May,both below and above the impoundment area.
Below the impoundment area,catches increased during
the period May 1-15 and then decl i ned at all habitat
1ocat ions throughout the summer until catches agai n
increased at tributary mouths in September.Within
thl;!impoundment area,catches were highest in June
and July and declined towards the end of summer and
early fall (Table E.3.16).
Changes in distribution and catch of grayling are
associated with migrational movements to spawning
grounds and overwi nteri ng areas that may have been
i niti ated in response to surface water temperature
(ADF&G 1981e).Below the impoundment area,hi gh
catches in May are associated with migration from the
mainstem Susitna into nonglacial tributary spawning
grounds.High catches in September are probably
associated with migrational movements back to over-
wintering areas in the mainstem Susitna.
Within the impoundment area in May and June,grayling
appeared to move upstream into pool-type habitat in
tributaries where they had spawned.The movement may
be associated with increasing water temperatures
(ADF&G 1982a).As surface water temperatures began
to decrease in late summer and early fall,lower num-
bers of fi sh were observed in these upper stream
reaches and tagged fish were observed migrating down-
stream.Small-scal e ·di stribut i on patterns and abun-
dance within upper stream reaches are determined
primarily by streamflow and channel morphology.
E-3-39
2.2 -Species Biology and Habitat Utilization
Observed preferred g rayl i ng habitat characteri zed by
high pool/riffle ratios,large,deep pools,and mode-
rate velocities (ADF&G 1982a).
Addit i onal di stri buti on patterns in the impoundment
reach were documented by catchi ng,taggoi ng and re-
leasing 2511 grayling during 1981 (ADF&G 1981f).
Many tributary fish moved into the Susitna mainstem
for overwintering.Analysis indicates that there is
a wide range of intertributary migration as well as
movement within individual tributaries.
Grayling population estimates were calculated for the
reaches of maj or tri buta ri es to be inundated by the
Devil Canyon and Watana impoundments (Table E.3.17).
The 1982 estimates were based on tag/recapture data
during July and August 1982,while the 1981 estimates
were based on results from the entire summer period.
There were insufficient tag returns from Watana Creek
in 1981 and from Tsusena and Fog creeks in 1982 to
deri ve estimates.The 1982 popul at i on estimate was
calculated for age groups (Table E.3.18).The total
grayling population in the impoundment zone was esti-
mated to be at least 16,000 in 1982,while the popu-
lation of grayling over 8 inches (20 cm)was estima-
ted to be 9375,excluding Watana Creek in 1981 (ADF&G
1981f,1982e).In 1982,summer density estimates
ranged from 323 grayling per mile (1.6 km)in Watana
Creek to 1835 grayling per mile (1.6 km)in Deadman
Creek for the reaches to be inundated (Tabl e
E.3.17).
There was no evidence of spawni ng at any sampl i ng
locations between Devil Canyon and Cook Inlet.In
the impoundment reach grayl ing fry were captured at
the Watana Creek study area in 1981,indicating
spawning in the immediate vicinity.It is thought
that adult grayling from the mainstem-Susitna below
Devil Canyon migrate into nonglacial tributaries to
spawn some time in late April or May.In the im-
poundment reach,spawni ng may occur from 1ate April
through early May under ice or during mid-May spring
floods in the lower reaches of all eight tributaries
sampled.Suitable spawning habitat,i.e.,proper
spawning gravel in pool regions,was observed in all
streams studied (ADF&G 1982a).Assullloing favorable
spawning conditions exist,it is not likely that
spawning habitat significantly limits grayling in the
impoundment area (ADF&G 1982a).Availability of
E-3-40
r::---
P"--~
~-'
-
2.2 -Species Biology and Habitat Utilization
-
-I
(i v)
(v)
summer feeding areas is probably more significant in
limiting the grayling population in this area.
Lake Trout
Near the Watana impoundment area,1 ake trout were
collected in Sally Lake and Deadman Lake.Both lakes
support a 1imited sport fi shery.Of the two 1akes,
only Sally Lake wi 11 be inundated by the proposed
Watana impoundment.All lake trout were captured
within 130 feet (39.4 m)of the shorel ine in less
than 6 feet (l.8 m)of water.A total of 35 lake
trout were captured:32 in Sally Lake and 3 in
Deadman Lake.All Deadman Lake fish were captured by
hook and 1 ine,while gill nets produced the highest
catches in-Sally Lake.Gill nets were not used in
Deadman Lake.Age group 5 dominated the catch.
During mid-August,both pre-and post-spawning 1 ake
trout were captured in Sally Lake.
Burbot
In Alaska,burbot are distributed in the Susitna and
Copper rivers,Bristol Bay drainages,throughout the
interior,and in the Arctic (McLean and Delaney
1978).Burbot mature between ages 3 and 6 in Alaska
and may 1 i ve a total of 15 to 20 years.Spawning
generally occurs between mid-December and April in
shallow water over a substrate of sand or gravel.
Movements and migration of burbot are not well docu-
mented.Burbot support a 1 imited sport fi shery in
the Susitna River.
During winter (November 1980 through May 1981)burbot
were caught throughout the reach between Devil Canyon
and Cook Inl et.The hi ghest catch rates were re-
corded downstream from Talkeetna,at the mouth of
Kroto Creek and Alexander Creek.Two mainstem sites
upstream from Talkeetna,one 2 miles (3 km)below
Portage Creek (RM 146.9)and one upstream from Lane
Creek (RM 114.4)produced the highest catches of
burbot in this reach (ADF&G 1981e).
During the summer of 1981,burbot catch rates for
Talkeetna to Cook Inlet reach and in the impoundment
reach upstream of Devil Canyon -increased as summer
progressed,reaching a maximum in September.In the
Devi 1 Canyon to Ta 1keetna reach,catches decl i ned
from early June until mid-July,then increased
E-3-41
2.2 -Species Biology and Habitat Utilization
throughout the remainder of summer.Burbot catches
during low flows were restricted to the mainstem,
deeper sloughs,and side-channels in the Devil Canyon
to TaHeetna reach.During high flows,burbot were
captured at a greater number of locations including
shallow side channels,sloughs and tributary mouths
(ADF&G 1981e).
Age groups 4,5 and 6 made up the majority of burbot
caught in the impoundment zone and age groups 4,5
and 8 made up the maj ority of burbot caught between
Devil Canyon and Cook Inlet.Population estimates
were not made in any of the reaches (ADF&G 1981e,
1981f).
Although no observations of spawning burbot were made
during the 1980-81 season,collection of female bur-
bot in early September with well-developed eggs and
collection of spent burbot from November to May sug-
gested that lower Susitna River burbot spawn between
November and January.Both sexually ripe and unripe
mature burbot observed from June through September
indicate that nonconsecutive spawning occurs for
Susitna River burbot.Location of spawning and rear-
ing areas in the Susitna were not documented,al-
though juvenile burbot were captured at Alexander and
Kroto creeks (ADF&G 1981e).
(vi)Round Whitefish
Round whitefish are distributed across all of arctic
and interior Al asl<a.They are normally abundant in
clear-water streams with gravel-cobble substrate but
can be found in large glacial rivers and lakes.
Whitefi sh mature at age 4-7,and spawni ng occurs in
1ate September through October over gravel substrate
in the shallows of rivers and inshore areas of lakes
(Morrow 1980).Upstream migrations are often asso-
ciated with spawning.
Round whitefish were captured at four locations (all
below Talkeetna)during the 1980-1981 winter studies.
The fish were all captured O as they moved upstream
during March,April,and May.The presence of white-
fi sh near the mouths of tri butary streams in the
March to May period after none had been caught in the
same locations between November-February,indicates a
general pattern of movement into the various tribu-
taries in the spring (ADF&G 1981e).
E-3-42
-
2.2 -Species Biology and Habitat Utilization
(v i i)
During the summer,the incidence of whitefish caught
in the Devil Canyon and Cook Inlet reach was hi gheir
than during the winter and peaked in June and
September.The most producti ve sites were Anderson
Creek,Sloughs 10 and 11,and Portage Creek mouth.
The most prevalent age groups were'ages 3,4,and 5
(AOf&G 1981e).Round whitefish were al so captured
upstream of Devil Canyon during the summer.Jay and
Kosina Creeks were the most productive areas for
round whitefish in the impoundment reach.Agegroup
7 was encountered most frequently (ADf&G 1981f).
Humpback Whitefish
In Alaska,there is a complex of three closely
related species of whitefish:humpback whitefish,
Alaska whitefish,and lake whitefish.Because of
similar appearance and overlapping distributions,the
data call ected on the three species have been
reported under thegeneralt>l'eadingof humpback white-
fish.The Alaska whitefish is not recognited by
AfS/ASIH (Robins et ale 1980).
Al,aska whitefi sh are 1argely stream inhabitants and
undertake 1engthy up-and downstream mi grat ions to
and from spawning rounds.Spawning occurs in
September c 0 er-.Lake w 1 te 1 s ri -
mar"·1n lakes but spawn in rivers or creeks betwee
tober and December.Humpback whitefi sh is appar-
ently the only species of whitefish that can be con-
sidered anadroJl1ous,although migration ·habits var
i dely indifferent systems.Spawni ng m"" s
gen nOctober and
November (Morrow 1980).
During the 1980-'81 winter,a single humpback white-
fi shwas captured below the mouth of Monta,naCreek.
During the-summer of 1981,peak catcmes 'were made in
early June and 1ate September (ADf&G 1981e).Largest
catches per unit effort were recorded at the mouth of
Anderson Creek,the mouth of Portage Creek,and a
slough at RM 23.8.Generally,humpback whitefish
were most abundant in Ute ralkeetna to Cook Inlet
rea:Ch,.fi sh collected ranged from ages 2 to 7;age 4
was the predominant age group (ADF&G 1981e).
No evidence of humpback whitefi sh spawni ng was col-
1ected at any samp 1i ng 1ocat ion betweefl nevi ~'Canyon
and Cook Inlet in 1981.Inspections of dissected
E-3-43
I
2.2 -Species Biology and Habitat Utilization
fish caught from mid-September to early October
showed well developed gonads,but fish were not ready
to spawn.Because no whitefish were caught or
observed after October 7,it was specul ated that
spawning must occur after this date (ADF&G 1981e).
(viii)Longnose Sucker
The 10ngnose sucker,the only representative of the
sucker family found in Alaska,is ubiquitous and
occurs in most of the mainland drainages.Spawning
usually occurs in spring after ice out.Spawning
runs (i.e.,movement from lakes into inlet streams or
from deep pool s into shallower,gravel-bottomed
stream areas)are initiated when water temperatures
exceed SoC (41°F).Longnose sucker feed almost ex-
clusively on benthic invertebrates but will occasion-
ally ingest live or dead fish eggs (Scott and Cross-
man 1973).
Longnose sucker were coll ected throughout the study
area from Cook Inlet to the upper reaches of the im-
poundment area.No specimens were collected during
wi nter sampl i ng.Duri ng the summer of 1981,adult
sucke rs were captured in the impoundment zone from
May-September,generally near the confluence of main-
stem ri ver and the tributary streams (ADF&G 1981f).
Du ri ng the same peri od,the percentage of habitat
locations where fish were collected was relatively
high in June from Devi1 Canyon to Cook Inlet with
lower catches recorded during July and August.The
percentage increased agai n duri ng September between
Talkeetna and Cook Inlet but not between Devil Canyon
and Talkeetna.Anderson Creek,Kroto Creek,Sunshine
Creek,and the mainstem of the Susitna River (RM
40.6)were the most productive locations.The most
prevalent ages were 4,5 and 6.
(ix)Threespine Stickleback
Threespine stickleback generally inhabit shallow
areas in bays and estuaries and in rivers not more
than a hundred miles upstream from the coast.Win-
teri ng areas tend to be in deeper waters.St i ckl e-
back feed mainly on small crustaceans and insects.
Threespine stickleback were collected throughout the
Devil Ca nyon to Cook In 1et reach of the Sus itna
River.Catches per unit effort in the Lower River
E-3-44
F-,~
I~
-
-
2.2 -Species Biology and Habitat Utilization
were hi gher t overall t than those in the Devil Canyon
to Talkeetna reach.The number of habitat locations
that produced threespine stickleback was highest in
June and dec1 i ned steadi 1y to September.The hi gher
percentage in early summer indicated that fish had
been involved in spring spawning movement.This
acti vity was not observed in September (ADF&G
1982a).
(x)Cottids
All sculpin species captured in the Susitna River
have been grouped under the general headi ng of cot-
tids.The slimy sculpin is the most common cottid
found in the Susitna t although there is a possibility
that three other speci es may be present below the
impoundment area.
-(xi)
Between November 1980 and October 1981,cottids were
captured throughout the Devil Canyon to Cook Inlet
reach of the Susitna River (ADF&G 1981e).The catch
rate in the impoundment area from May to September
was 0.11 per trap day (ADF&G 1981f).The percentage
of sampling locations producing catches in the Lower
River attained a high in late August and a low in
late July.For the Devil Canyon to Talkeetna reach,
there was a high in early July and a low in late
September.Habitats associated with clear-water
tributaries consistently produced the highest catches
throughout the study area from Cook In1 et to above
the proposed impoundment zone (ADF&G 1981e,1981f).
Lamprey
The arctic 1ampreYt one of four lamprey species that
occurs in A1aska t was observed in the Susitna River
during 1981 (ADF&G 1981e).The Pacific 1ampreYt an
anadromous speci es that has been reported to range
into the lower Susitna River (Morrow 1980),was not
observed during 1981 investigations.
Some popu1 at ions of arcti c 1amprey are composed of
both anadromous and freshwater forms.It was specu-
lated that a portion (30 percent)of the Susitna pop-
ulation is anadromous based on analysis of length
frequenci es (ADF&G 1981e).The anadroillous form is
parasitic;hosts include adult salmon,trout,white-
fish,ciscoes,suckers,burbot,and threespine stick-
leback (Heard 1966).The freshwater forms have been
reported to be both parasitic and nonparasitic.
E-3-45
2.2 -Species Biology and Habitat Utilization
Arctic lamprey spawn during the spring in streams of
low-to-moderate flow.Eggs develop into a larval
stage,whi ch spend one to four years burrowed into
soft substance.After an i ndefi nite peri od,adults
migrate upstream to spawn.
Arctic 1amprey were captured at 14 sampl ing sites
between RM 10 and RI'v1 101 that were surveyed from
November 1980 through September 1981.During the
winter surveys,the or.ly habitat site to produce
arctic lamprey was Rustic Wilderness,where one
1amprey was captured.All other 1 amprey were col-
1ected duri ng the summer months.Lamprey were not
coll ected in the impoundment area (ADF&G 1981e).
The hi ghest catch frequency was recorded duri ng the
September 1 to 15 sampling period.All lamprey taken
during this period were collected at tributary sites
downstream from RM 50.5.The lowest i nci dence of
capture for this species during the summer was ob-
served in the July 16-31,1981 sampling period (ADF&G
1981e).
2.2.2 -Habitat Utilization
The physical parameters associated with the free-flowing charac-
teristics of the Susitna River determine the qual ity of the
aquatic habitat available to the fishery resources.Alteration
of these physical pa rameters woul d ult imately affect associ ated
fish populations.The complex relationship between the aquatic
habitat and the physical parameters that exist is compounded by
the effects of seasonal and yearly fluctuations in physical habi-
tat components.
Most of the baseline description of the Susitna River aquatic
habitat presented below is based on reports of habitat evaluation
studies conducted by ADF&G during the 1980-81 field season (ADF&G
1981c,1982a)and by results of continuing stud.ies during the
1981-82 season.These studies have identified seasonal habitat
characteristics of selected anadromous and resident species with-
in the study area.
Species occurrence,relative abundance,and the significance of
aquatic habitat to species and important life history stages are
discussed below for each of the three defined study reaches:
Oshetna River to Devil Canyon,Devil Canyon to Talkeetna,and
Talkeetna to Cook Inlet.
E-3-46
-
I~
2.2 -Species Biology and Habitat Utilization
The gradation of habitat types available in the Susitna River
were grouped into four classes:mainstem,side channel,slough,
and tributary mouth.Each of these habitat types encompass a
range of physical attributes rather than a set of fixed
characteristics (Trihey 1982d).
-Mainstem habitat consists of that portion of the Susitna River
that conveys streamflow at all times.Both single and multiple
channe 1 reaches are i ncl uded in th is catego ry.The phys i ca 1
characteristics of mainstem habitat in the Susitna River
reflect the integration of the streamflow,sediment,and ther-
mal regimes of the upstream basin with the topography and geol-
ogy of a particular river segment.Ground water and tributary
inflow are generally minor contributors to streamflow within a
ri vel'segment,although tri butari es provi de more than hal f of
the flow in the river downstream from Talkeetna.Total sedi-
ment load and suspended sediment concentrati ons ar'e dependent
upon glacial melt and rainfall or snow melt.Stream tempera-
ture responds primarily to meteorological conditions and
directly influences intergravel water temperatures.
-Side-channel habitat consists of those portions of the Susitna
River that normally convey streamflow only during the high flow
open-water season but which become appreciably dewatered during
periods of low flow.In general,shallower depths,lower
velocities,and smaller streambed materials occur in side chan-
nels than occur in the mainstem.However,the streamflow,
sediment,and thermal regimes of side-ch-annel habitats respond
di rect ly to mai nstem condit ions.Tributary and ground water
inflow may prevent si de-channel habitats from becomi ng com-
pletely dewatered as mainstem flows receed;however,the pres-
ence of these inflows is not considered a necessary component
to define side-channel habitat.
-Sloughs are overflow channel s that convey gl aci al meltwater
from the mai nstem during'moderate and hi gh-flow peri ods and
that convey clear water from local runoff and ground water dur-
ing intermediate and low-flow periods.Sloughs are generally
located on the downstream side of old,well-vegetated point
bars.The-streambed el evat i on ina 510ugh is notably hi gher at
the upstream entrance than at the mouth,and sloughs often
funct i on 1i ke small st re'am sy stems.A port i on of the channel
in each slough,which may vary in 1ength from several hundred
to several thousand feet,conveys water without the influence
af the mainstem backwater.
The physical characteri sti cs of slotlgh habitat appear to depend
upon the tnteraction of four-prtrrcipal fa,etors:'the cHscharge
of the mainstem Susitna River,surface runoff patterns from the
adjacent catchment area,ground water flow contributions,and
E-3-47
2.2 -Species Biology and Habitat Utilization
ice processes withi n the mai nstem ri ver system.These four
principal factors interact to varying degrees during different
portions of the year to provide a unique habitat type.
The amount of streamflow in the mainstem of the Susitna River
influences habitat conditions in the sloughs:(1)by causing a
backwater effect at the mouth of the slough which facil itates
access into the slough and (2)by overtopping the upstream end
of the slough at high flows,thereby flushing debris and fine
sediments from the slough.Local surface runoff contributes a
greater portion of the clear-water flow to the slough than the
ground water upwelling during the ice-free period of the year.
During winter months~ground water provides nearly all of the
flow in the sloughs.The ground water upwelling in the sloughs
maintains open-water conditions in the slough during the winter
season.
Spring breakup combined with high flows in the mainstem river
also maintains the character of the slough habitat by flushing
debris and beaver dams from the sloughs,which can be barriers
to upstream migrants during periods of low flow.Mainstem
ri ver wi nter ice processes al so contri bute to the mai ntenance
of ground water upwell i ng in the sloughs duri ng the wi nter
season.
-Tributary habitat consists of the full complement of habitats
that occur in the tributary streams of the Susitna River.The
streamflow~sediment,and thermal regimes reflect the integra-
tion of the hydrology~geology and climatology of the tributary
drainage.Therefore,physical characteristics of tributary
habitat are not dependent on ma i nstem ri ver cond it ions that
exist at the tributary mouth.At the mouth of most tributaries
the stage of the mainstem river causes a backwater that extends
into the tributary~and the tributary flow creates a clear-
water plume along the bank in the mainstem.This interaction
provides another type of habitat (tributary mouth habitat)that
is considered a subset of tributary habitat.
(a)Oshetna River to Devil Canyon
The impoundment reach of the Susitna River flows through a
steeply cut,degrading channel.From Devil Creek (RM 162)
to the downstream end of Devi 1 Canyon (RM 150)~the ri ver
forms one channel that lies in a deep valley with an average
gradient of 31 ft/mile (5.9 m/km).From Oshetna River
(RM 233)to Devil Creek,the river is wider and often splits
into two or more.channels with an average gradient of
approximately 13 ft/mile (2.4 m/km).Substrates throughout
the impoundment reach and mouths of tributaries generally
cons i st of rubble ~cobble,and bo ul ders,often embedded in
sand;gravels are present in some locations (ADF&G 1981c).
E-3-48
-
-
2.2 -Species Biology and Habitat Utilization
Because of the inaccessibility of the Devil Creek and Devil
Canyon area and the apparent lack of suitable fisheries
habitat,the study area was limited to that section of the
Susitna Ri ver from the Oshetna River to Fog Creek (RM 1.77)
(ADF&G 1981c).Based upon a preliminary reconnaissance of
the upper Susitna Ri ver basin (ADF&G 1977),eight major
tributaries were selected for fisheries studies:Fog and
Tsusena creeks in the proposed Devil Canyon impoundment;and
Deadman,Watana,Kosina,Jay and Goose Creeks and the
Oshetna River in the Watana impoundment.For the purpose of
this study,the first mile of each of these streams upstream
from their confluence with the Susitna River was sampled.
To assess mainstem utilization,sampling was conducted in an
area 300 feet (90 m)upstream and downstream from a tribu-
tary's confluence with the Susitna River.
Overall values of the physiochemical parameters measured in
the mainstem during May to September (ADF&G 1982a)include:
-Well-oxygenated water (9.0-14.1 mg/l);
-pH values near seven or slightly higher (6.8-7.9);
-Moderate conductivity values (44-248 umhos/cm);
-Water surface tempe ratures in the range of 1.5-12.6°C
(34.7-54.7°F);and
Low turbidity levels in the tributaries (0.3 to 19 NTU)
compared to the mainstem (10 to 175 NTU).
(i)Mainstem Habitat Near the
Confluence of Major Tributaries
-Species Occurrence and Relative Abundance
Although adult chinook salmon were documented for
the first time at RM 156.8 in 1982,no other anad-
romous species were reported in the mainstem
Susitna in the impoundment reach (ADF&G 1982e).
Thi s supports the current opi ni on that hyd raul ic
characteristics of the Susitna River at Devil
Canyon act as a barrier to upstream salmon movement
during high flows (ADF&G 1982a).
S'even resident species occur in the mainstem:arc-
tic grayling,longnose sucker,humpback whitefish,
round whitefi sh,Dolly Varden,burbot,and s1i my
sculpin.The longnose sucker,round whitefish,and
E-3-49
2.2 -Species Biology and Habitat Utilization
burbot were almost exclusively captured in the
mainstem near the mouths of the tributaries.Based
on tagging studies,the arctic grayling occupied
mainstem locations primarily during winter.
-Significance of Habitat
The mainstem Susitna River in the impoundment reach
prov ides pri mary overwi nteri ng hab i tat and mi gra-
t i on routes between tr"j butari es for arctic grayl i ng
(ADF&G 1981f).
Burbot use the ma i nstem i mmed i ate1y up or down-
stream from tributaries as year-round habitat.All
burbot catches in the impoundment area were made in
the mai nstembetween May and September .(ADF&'G
1981f).It is unlikely that tributaries would be
utilized during winter months because of ice condi-
t ions.
Roundwhitefi sh and longnose suckers al so use the
mai nstem near tributary confl uencesas year-round
habitat.However,no specific spawning or rearing
areas were identified (ADF&G 1981f).
(ii)Tributaries
Species Occurrence and Relative Abundance
At least two r~sident species,arctic grayling and
cottids,occur in tributaries.Other species 'cap-
tured near the mouths of tributaries,as di scussed
above under Section (i),probably also use the tri-
butari es periodically;howe~er,none were captured
in the tributaries during the field studies.
Abundance estimates for grayH ng from 1982 data
indicate that in excess of 16,.300 grayling inhabit
clear-water tri butari es in the impoundment zone
during the summer (Table E.3.1T).Total catch of
cottids was 38 in 352 trap days.
-Significance of Habitat
Tributaries are primarily utilized by grayling as
spawning and rearing habitat (ADF&G 1982a).Al-
though spawning has not been ,observed in the im-
poundment )zone,suitable spawni ng habitat (sandy
gravel)does exist in all of the tributaries
E-3-50.
2.2 -Species Biology and Habitat Utilization
sampl edt and it is 1i kely that spawni ng occu rs in
the lower reaches of these tributaries.Grayl ing
fry were fou nd 1n the lower reaches of Watana
Creek t indicating that spawning had occurred near-
by.Grayl"ing that have completed spawning move
upstream into areas that have pool type habitats
where they remai n throughout the summer.Large,
deep streams with a high pool/riffle ratio and
moderate streamflow velocity (below 2.0 ft [0.6 m]
per sec)t such as the Oshetna Ri ver and Kosi na
Creek,provide optimal habitat (ADF&G 1982a).
-
-
,~
(b)Devil Canyon to Tal keetna
In the reach of the Su sitna Ri ver from Devi 1 Canyon to
Talkeetna,the river channel is relatively stable and
straight with some meandering and minimal braiding.Nume-
rous islands,gravel bars t and sloughs are present.Flow
alternates between a single channel and spl it channels con-
fi gu ration throughout the reach.Between Cu rry fR'M 120)and
Talkeetna the approximate gradi ent is 8.1 feet per mi 1e
(1.5 m/krn).Typical substrate between Curry and Talkeetna
is gravel,rubble,and cobble with small amounts of sand and
silt.Above Curry the substrate varies from silt to
bedrock~The majority of mai nstem shorel i ne substrate is
rubbl e and cobbl e whereas si lt and gravel are the most
common substrate in sloughs and slow water areas.Below
Curry,streambank vegetation is dense spruce/hardwood
forest.In addition to numerous smaller streams draining
the surrounding hillsides,the principal tributaries to the
Susitna River in the Devil Canyon to Talkeetna reach include
Portage Creek t Indian River;Gold Creek t Fourth of July
Creek,Lane Creek t and Whiskers Creek.
A breakdow,n of the habitat study sites in the Devi 1 Canyon
to Talkeetna reach includes 11 slough sites t 8 mainstem or
side-channel sites t and 5 tributary sites.Ranges of
physiochemical parameters measured\for these sites from May
to September 1981 are shown in ADF&G (1982a).Ranges given
for tributary ~ites included all of the sampling sites from
t:hat particular tributary.Overall trends for physiochemi-
~al parameters measured in this reach included:
-High dissolved oxygen (8.8-12.8 mg/l);
-Moderate conducti vity reading<st (15-222 umhoslcm);
E-3-51
2.2 -Species Biology and Habitat Utilization
-pH values in the range of 6.1-7.8,slightly lower than the
impoundment reach or downstream.Tributaries such as
Whiskers Creek and Indian River had slightly lower pH
values than mainstem or slough sites;
-Turbidity level s were generally lowest at upstream
tributary sites (0.4-148 NTU).levels were also generally
lower in downstream tri butary sites and sloughs when the
influence of the mainstem Susitna was negligible.levels
were highest in the mainstem (23-230 NTU).
(i)Mainstem and Side Channels
The Susitna River from Devil Canyon to Talkeetna has
both single and split channel configuration reaches.
Single channel reaches are generally stable with
non-erodible banks controlled by valley walls,
bedrock or armor layer consisting of gravel/cobbles.
The channel is either straight or meandering.In
straight channel reaches,the thalweg often meanders
across the channel.Occasional fragmentary deposits
can be found in the floodplain.Split channel
configurations are characterized by moderately stable
channels with a gravel/cobble substrate.There are
usually no more than two channels in a given reach.
Channels are separated by well established vegetated
islands.The main channel behaves much like a single
channel at low flows with the side channels flowing
only at di scharges above about 20,000 cfs.Bankfull
now generally corresponds to the mean annual flood
(R&M 1982c).
-Species Occurrence and Relative Abundance
•Sal mon
Five species of Pacific salmon were observed in
the Susitna Ri ver between Devil Canyon and
Tal keetna.Studies indicate that adult salmon
utilize the mainstem upstream from Talkeetna from
late spring into the fall during migration and
spawning periods (ADF&G 1981b).Use periods for
adults of each species are:
Chinook--mid-June through July;
Sockeye--July 23 through mid-September;
Coho-~July 30 through September;
Chum--July 28 through mid-September;and
Pink--July 27 through August.
E-3-52
-
-I
!
,,-.
!
I
-
2.2 -Species Biology and Habitat Utilization
Relative abundance estimates based on 1981 and
1982 escapement data and population estimates are
given in Table E.3.5 for each of the salmon
species that utilize this reach of the Susitna
Ri ver pri marily as a passage way to spawni ng
areas.
J'uvenile salmon are also present in the mainstem
at various times of the year.Periods of use and
relative abundance are outlined below.
Chinook--During winter,juveniles were most
abundant in the rnai nstem.Pri or to June 1
through the end of July,age 1+juveniles were
abundant as they were observed moving
downstream in the mainstem.
Sockeye--In 1982 sockeye juveni 1es moved out
of the Devil Canyon to Talkeetna reach as ageofish,primarily during June and July (Table
E.3.9).
Coho--During winter,coho are most abundant in
the mainstem.During summer they are slightly
1ess abundant in the mai nstem than at the
tributary mouths.In 1982,out-migration
peaked in June.
Chum--The majority of the chum juveniles
migrated downstream prior to July 1 in 1982.
Pink--Studies to date have caught few pink
juveniles in the mainstem •
•Resident Species
Resident species reported in this reach included
all of the resident fish reported in the Susitna
River drainage (Table E.3.2)except for lake
trout.Resident fi sh observed throughout the
year in the mainstem include burbot and longnose
sucker.Other resident species were most abun-
dant in the mai nstem primari ly duri ng the 1ate
fall,winter,and early spring.
-Significance of Habitat
Based on existing data,the mainstem Susitna River
between Devil Canyon and Talkeetna ;s primarily
[-3-53
2.2 -Species Biology and Habitat Utilization
used by anadromous and resident species as a
mi grat i onal corridor and overwi nteri ng area.The
significance of mainstem aquatic habitat is
discussed below for various species of commercial
and recreational importance •
•Salmon
The mainstem reach from Devil Canyon to Talkeetna
serves as a migration corridor for a relatively
small percentage·of the total Susitna River
salmon escapement (Table E.3.5,Figure E.3.9).
During migration periods,various behavioral and
distribution patterns are associated with certain
characteristics of mainstem habitat,including
water depth,velocity,channel configuration,and
1ocati on or absence of obstructions (ADF&G
1981c)•
Generally,passage of adult salmon during migra-
tion corresponds with the summer high flow sea-
son.However,passage of adult salmon on a daily
basi s (measu red by si de-scan sonar)i ndi cated
that salmon movements decreased during periods of
highest flows (40,000 cfs)and increased as flows
subsided following major flow events (ADF&G
1982a).
It is hypothesized that increased water velo-
cities associated with peak f10ws discouraged
passage and encouraged milling (ADF&G 1982a).
Radiotelemetry investigation and gill netting
indicated that the confluence of the Talkeetna,
Chulitna and Susitna Rivers is a chum,pink,coho
and chi nook mi 11 ing area and that sockeye,chum,
coho,pink,and chinook mill in the mainstem one
mile below Devil Canyon.
Chum were observed spawning at 10 sites and coho
at 4 of the 11 mainstem spawning sites identified
in the Devil Canyon to Tal keetna reach du ri ng
1982.Mainstem spawning appeared to be re-
stricted by lack of suitable spawning substrate
and ground water upwelling (ADF&G 1981c,1982a).
Juvenile chinook and coho salmon use the mainstem
for overwintering.Salmon juveniles use the
mainstem for out-migration.
E-3-54
2.2 -Species Biology and Habitat Utilization
-
(i i)
•Resident Species
Resident species,other than burbot and longnose suck-
er,primarily use this mainstem area as a migration
channel to spawning,rearing,and summer feeding areas
in the tributaries.No malnstem spawning or rearing
areas have been located.Rainbow trout and grayl ing
overwinter in mainstem habitats~
Burbot and longnose sucker use the ma i nstem as year-
round habitat.Burbot catches during low flows were
restricted to the mainstem and deep side channels.
Ouri ng high flows,burbot were captured at a greater
number of locations,including shallow side channels.
Slough Habitat
The clear water in the sloughs originates from local sur-
face runoff and ground water upwe 11 i ng.Ground water up-
wells in the slough channels throughout the year,thus
keeping these areas relatively ice free"in the winter.
Observations indicate the Susitna River is the primary
source of the water in many of the sloughs ..Local runoff
is a primary water source in slough habitats in the
summer.
The stage in the mainstem controls the water surface
elevation of the lower portion of the sloughs by forming a
backwater that can extend some distance upstream into the
slough1/.This backwater is divided into two parts-
clear water and turbid water.The ma"instem water creates
a turbid plug at the mouth of the slough that backs up the
clear water in the slough.As the stage in the mainstem
drops,the size and character of the backwater changes.
At summer flows of approximately 8,000 to 10,000 cfs at
Gold Creek (RM 136.8),the backwater recedes.This
reduces the depth of water at the entrance to the sloughs.
In some cases,the slough mouth and the mainstem become
separated by a gravel bar.
When high mainstem flows overtop the head end of the
sloughs,the flows fl ush the fi ne sed iments that accumu-
late in the lower.portion of the sloughs.As peak flows
in the mainstem subside and the stage in the mainstem
drops below the head end of the slough,discharge through
the slough drops and the water in the slough begins to
clear.
lIAPpendix E.2.A provides an incremental description of mainstem
discharge influence on slough hydraulic conditions.
E-3-55
2.2 -Species Biology and Habitat Utilization
Because there is much diversity in the morphology of
individual sloughs.the flows at which they are
overtopped vary considerably.In general.most side-
channel sloughs are overtopped at flows between
20.000 and 24.000 cfs.Other sloughs are overtopped
only during flood events such as spring breakup.
In the summer.when mainstem temperatures are ranging
from 8°to IrC (46.4°to 53.6°F).intergravel tem-
peratures in the sloughs range from 4°to 6°C (39.2°
to 42.8°F).Some winter temperatures measured in the
sloughs and the mainstem indicate that when mainstem
temperatures range from 0.1°to 0.5°C (32.2°to
32.9°F).intergravel temperatures ranged from
2°to 4°C (35.6°to 39.2°F)(Atkinson 1982).
-Species Occurrence and Relative Abundance
•Salmon
Adults and/or juveniles of five salmon species
have been observed in slough habitat between
Dev il Canyon and Tal keetn a.Resu lts of escape-
ment and spawning surveys indicated that adult
sockeye and chum salmon were the most numerous
salmon in these sloughs during peak spawning
periods (ADF&G 1981b.1982e).In 1981.an esti-
mated 3526 chum and 2315 sockeye spawned in
sloughs in this reach.while in 1982 an estimated
3674 chum and 1402 sockeye spawned in these habi-
tats.Pink salmon were less abundant.with an
estimated 28 and 735 spawn-ing in sloughs in 1981
and 1982.In 1982.coho were observed spawning
in one of the sloughs (SA).No chinook have been
observed spawning in the sloughs.Spawning
counts for individual sloughs are reported in
ADF&G (1981b.1983)(Figures E.3.12 to E.3.17).
Estimates of the total number of spawning salmon
by slough are given in Table E.3.12.
Studies of species occurrence and relative abun-
dance of juvenile salmon in slough habitat indi-
cate the following information:
Compared to other habitats in this reach.
juvenile chinook salmon are abundant in all
sloughs during winter and relatively abundant
in selected clear-water sloughs during summer.
E-3-56
f"""
I
2.2 -Species Biology and Habitat Utilization
Juvenile coho salmon are abundant at slough
sites during winter and less abundant but
still present at slough sites during summer.
Preliminary data indicate that chum,pink,and
sockeye fry were present in slough habitat
during part of the summer •
•Resident Species
All resi dent speci es reported in thi s reach of
the Susitna drainage have been observed in slough
habitat between Devil Canyon and Talkeetna except
for lake trout.
Available data indicate that most species are
present in slough habitats as well as the main-
stem throughout winter.During summer,most
adult residents are not abundant in slough habi-
tat.Those that were relatively abundant in
slough habitat during summer included burbot,
longnose sucker,and rainbow trout.Previous
studies indicated that juvenile whitefish,gray-
ling,and rainbow trout were abundant in slough
habitat during late summer (Friese 1975).
-Significance of Habitat
Slough habitat between Devil Canyon and Tal keetna
is used by various anadromous species primarily for
spawni ng and al so for reari ng and overwi nteri ng of
juveniles;it is equally important for overwinter-
ing and rearing of various resident species.The
significance of slough habitat is discussed below
for species of commercial and recreational impor-
tance •
•Salmon
Slough habitat in thi s reach serves as spawni ng
habitat for sockeye and chum salmon and less
important spawni ng habitat for pink salmon
(Table E.3.12 and Figures E.3.12 to E.3.17).
In 1981 and 1982,83 and 108 percent of the sock-
eye estimated to have passed Curry Station were
estimated to have spawned in sloughs in this
reach.For the same two years,27 and 12 percent
of the chum salmon estimat~d to have passed Curry
Stati on,spawned in sloughs.Factors contri bu-
ting to the salmon spawning in the sloughs in
this reach are outlined below:
E-3-57
2.2 -Species Biology and Habitat Utilization
Clear-water base flows originating from
sources such as ground water upwelling,local
surface runoff,or interstitial inflow insure
maintenance flows.
The presence of ground water upwelling in the
sloughs oxygenates spawning substrate,keeps
silt from compacting the spawning gravels,and
provides a stable temperature regime that
maintains incubating embryos through the
wi nter.
Sloughs also serve as rearing and overwintering
habitat for ju venil e chi nook and coho salmon.
During summer,tributary sites appear to be more
important chinook rearing habitat,although clear
water sloughs also provide rearing habitat.Coho
juveniles appear to use sloughs and tributary
mouth sites for summer rearing.The importance
of sloughs as ju veni 1e overwi nteri ng and summer
rearing habitat may be related to:
Ice-free clear-water conditions during winter
compared to lowered flow and icing in coho and
chinook salmon natal tributaries;and
During high summer mainstem flow,the high
stage of the mainstem acts as a hydraulic con-
trol at the slough outlet,increas"ing the
depth of water in the lower end of the slough.
These cl ear-water areas promote benthi c pro-
duction,which improves the qual ity of the
rearing habitat for juvenile salmon •
•Resident Species
Slough habitat between Devil Canyon and Talkeetna
provides overwintering habitat for adult rainbow
trout,grayling,and whitefish;year-round habi-
tat for adu It bu rbot and longnose sucker;and
reari ng habitat du ri ng 1ate summer months for
juvenile whitefish,grayling,and rainbow trout.
The importance of sloughs as overwintering habi-
tat is related to the same factors as discussed
above for juvenile salmon.
(iii)Tributary Habitat
The depth of water in the mouth of tributaries
between Devil Canyon and Talkeetna is sensitive to
E-3-58
i"
I
I
I
.....
I
I
2.2 -Species Biology and Habitat Utilization
changes in mainstem flow.At high flows t the
mainstem creates a backwater at the tributary moQth t
thus i ncreas i ng the water depth.The 1 i nea 1 extent
of the backwater in the tri butary depends on the
stage in the mainstem and the gradient of the
tributary.At low mainstem stages t the backwater is
eliminated t resulting in shallower water and
increased flow velocities at the mouth.
Small deltas are formed at the mouth of most of the
tri butari es.As the tri butary enters the mai nstem
river t the change in gradient and sUbsequent change
in flow velocity cause the tributary to drop trans-
ported materials if the velocity in the mainstem is
not sufficient to carry the material downstream.As
the stage in the mainstem river decreases t the tribu-
taries become perched above the river t that iS t the
tributaries flow across steep deltas.Were they to
remain under low mainstem flow conditions t upstream
passage of adult salmon and resident fish would be
inhibited or eliminated.However t based on studies
computed by R&M Consultants (1982f)t the tributary
flows are sufficient to cut through the deltas to
establ ish a channel at a new gradient.··In 1982 t the
tributaries were observed to cut throught their
deltas during the low flows "in August.Even during
the low August flows t most of the t ri butari es had
sufficient energy to move the delta material (R&M
Consultants 1982f).
-Species Occurrence and Relative Abundance
•Salmon
Except for sockeye salmon t the salmon species
present in the Susitna drainage were observed in
tributaries within the Devil Canyon to Tal keetna
reach.Spawning counts for individual tributary
index areas are given in ADF&G (1981b t 1982e)
(Figures E.3.12 to E.3.17).
Species occurrence and relative abundance of
juvenile salmon in tributaries or at tributary
mouths varied by season and by species.Results
of studies to date are outlined below:
E-3-59
2.2 -Species Biology and Habitat Utilization
Juvenile chinook salmon are most abundant at
tributary mouths during summer.Redistribu-
tion of juveniles from areas of emergence in
tributaries to more favorable rearing habitat t
including the mouths of tributaries t occurs
throughout the summer as fish become more
mobil e.
Juvenile coho were slightly more abundant at
tributary mouth sites than at Illainstem sites
du ri ng summer.
•Resident Species
All resident species except for burbot t longnose
sucker t and 1ake trout were abu ndant i nt and at
the mouths oft cl ear-water tributari es du ri ng
summer months.Limited i nforlllati on on winter
distribution and abundance indicates that few
resident fish overwinter in the tributaries.
-Significance of Habitat
•Salmon
Tributary habitat in this reach serves as primary
spawning habitat for chinook t coho,chum t and
pink salmon (ADF&G 1981b t 1983).Important
spawning tributaries include Indian River (chi-
nook,pink,chum and coho),Portage Creek (chi-
nook,coho,pink and chum),Gash Creek (coho),
Lane Creek (chinook and pink salmon),and Fourth
of July Creek (chinook,pink and chum)(Figures
E.3.12 to E.3.17).
Tributaries in this reach also serve as rearing
and summer feeding habitat for chinook and coho.
Tributary mouths also provide important milling
and reari ng areas for ju venil e chi nook and coho
salmon.Occurrence of age 0+coho was
particularly high at tributary mouth sites (ADF&G
1982a).
•Resident Species
Between Devil Canyon and Talkeetna,tributaries
provide spawning habitat,juvenile rearing areas,
and summer feeding habitat for several resident
species including rainbow trout t arctic grayling t
E-3-60
"""
......
2.2 -Species Biology and Habitat Utilization
round whitefish,and Dolly Varden (ADF&G 1981e,
1982a).In general,these fish migrate from
mainstem or slough habitat to the clear-water
tributaries to spawn ;n the spring (or early fall
for Dolly Varden).Once spawning is completed,
the fish move into favorable tributary habitat
for rearing and summer feeding.As freezeup
begins,the fish migrate from the tributaries to
the mainstem or deeper pools near the mouths of
tributaries •
,-.
.....
(c)Cook Inlet to Talkeetna
Below Talkeetna,the Susitna River ;s moderately to exten-
sive1ybraided throughout most of the reach.From the inlet
to Bell Is1~l[ld (RM 10),the river is separated into two
braided channels;from Bell Island to the Yentna River (RM
27),a single meandering channel is formed.From the Yentna
River to Sheep Creek (RM 70),the river is moderately to
extensi ve1y brai ded,wi th forested i sl ands and nonforested
bars between the channels of the river.The river is re-
duced to a single channel near the Parks Highway Bridge (RM
84),and braiding becomes moderate from this point to
Talkeetna.Gradients vary considerably ;n this reach.From
Cook Inlet to RM 50,gradient is 1 ft/mi1e (0.2 m/km);from
RM 50 to 83,it is 5.9 ft/mi1e (1.1 m/km);and from RM 83 to
Talkeetna,the gradient is 6.9 ft/mile (1.3 m/km).Typical
substrate in the reach is si 1t and sand with'some gravel and
rubble.Major tributaries include:Alexander Creek,Yentna
River,Kroto Creek (Deshka River),Chulitna River,and the
Talkeetna River.Flows in these tributaries are consider-
able.The Chulitna and Talkeetna Rivers contribute about 57
percent of the total flow below the conf1 uence near
Talkeetna (R&M 1982c).
Study sites located in this lower reach included 11
tributary mouth sites,5 tr"ibutary sites,8 slough sites,
and 5 mainstem and side..,channe1 sites.The ranges for
physiochemical parameters in this reach are given in ADF&G
(1982a).The data collected include the following:
-Tributaries,sloughs,and the mainstem all exhibited high
dissolved oxygen readings (7.6-12.9 mg/1).
-Conductivity was generally low in the tributaries (19-46
umhos/cm)and moderately high in ma;nstem and slough sites
(29-216 umhos/cm).
-pH values were ; n the 6.1-8.0 range,with tributaries
having the lowest pH values.
E-3-61
2.2 -Species Biology and Habitat Utilization
-Turbidity was lowest in tributaries.particul arly Caswell
and Montana creeks (0.3-1.9 NTU),and highest at mainstem
and slough sites (2.2-255 NTU).
(i)Mainstem and Side Channels
Braided river reaches such as the lower Susitna are
characterized by two or more interconnecting channels
separated by unvegetated or sparsely vegetated gravel
bars.The active floodplain is wide and sparsely
vegetated,and contains numerous high water channels
and occasional vegetated islands.Active channels
are typically wide and shallow and carry large quan-
tities of sediment at high flows.Bars separating
the channels are usually low,gravel-surfaced.and
easily erodible.The lateral movement of channels
within the active floodplain of a braided river that
carries large quantities of bed load is expected to
be high.The channels shift either by bank erosion
or by channel diversion into what was previously a
high-water channel.Gravel deposits may partially or
fully block channels,thereby forcing flow out of the
channel to develop a new channel.
Because braided river channels are wide and shallow,
they are more sensitive to flow reductions than the
deeper channel s of a sp1 it channel system,i.e.,a
drop in stage could result in a substantial reduction
in the width of the river and loss of large areas of
flow along the margins of the channel.
Because the thalwegs of the side channels are usually
at higher elevations than the main channel thalweg,
they are more sensitive to fluctuating river stages.
As a result,they may be completely dewatered at low
flows.Side channels are not subject to as high a
flow velocity as the main channels,thus the
substrate is not scoured from these channels as
easily.The water qual ity in the side channel s is
the same as that found in the mainstem.
-Species Occurrence and Relative Abundance
Salmon
Adult salmon pass through this reach of the main-
stem during spawning migration.Generally,the
migration period extends from late May into
September (specific dates are reported in Section
2.2.1[a]).The relative abundance of adult
E-3-62
-
-i
.-
.-
2.2 -Species Biology and Habitat Utilization
salmon in this reach is high because the entire
Susitna salmon run must pass through the lower
secti ons of the river in order to arri ve at
spawning grounds.Population estimates of the
number of salmon that migrate to various escape-
ment monitoring stations are given in Table E.3.5
and Figure E.3.8.
With the exception of sockeye salmon,the
majority of upper Cook Inlet salmon are bel ieved
to originate in the Susitna drainage and,
therefore,must migrate through portions of the
reach of mainstem between Talkeetna and Cook
Inl et.
Juvenile chinook salmon are relatively abundant
in this reach of the mainstem during winter
months.Juvenile coho are less abundant and more
often associated with tributary mouth sites •
•Other Anadromous and Resident Species
Other anadromous species observed in thi s reach
include Bering cisco and eulachon.Bering cisco
are abundant in the mainstem from August to
October (ADF&G 1982a)•.Eulachon were observed in
the lower 48 mil es of the reach in 1982,and
lower 58 in 1981 (ADF&G 1983).
All resident species found in the Susitna drain-
age except for 1 ake t rout were found in thi s
reach or the mai nstem.Lamprey were observed in
this reach but not in other reaches of the
Susitna River (ADF&G 1981e).
-Significance of Habitat
•Salmon
The port i on of t he reach closest to Cook In 1et
serves as a migration corridor for the enti re
Susitna River salmon run.
Salmon spawni ng habitat in the rnai nstem or si de
channels of the reach is limited and is
comparable to the spawning habitat discussed for
the Devil Canyon to Talkeetna reach.Of the six
mai nstem or si de channel spawni ng sites i dent i-
fied in 1981,chum salmon occupied six and coho
E-3-63
2.2 -Species Biology and Habitat Utilization
salmon occupied one (Table E.3.13,ADF&G 1981a}.
No mainstem or side-channel spawning was observed
for chinook or sockeye salmon.Mainstem and side
channel spawning habitat is probably restricted
because of the 1ack of su i tabl e spawni ng sub-
strate and upwelling,which are two of the key
factors determining substrate suitability for
spawning.
Mainstem habitat also provides overwintering for
chinook and coho juveniles,limited summer rear-
ing habitat,and a migrating channel for smolt
outmigration •
•Other Anadromous and Resident Species
The mainstem from Talkeenta to Cook Inlet serves
as primary overwintering habitat and as an
important migration channel.Bering cisco and
eulachon are anadromous species that use the
mainstem as a migratory channel from Cook Inlet
to their respective spawning areas.Arctic gray-
1 i ng,rai nbow trout,Dolly Varden,and round
whitefish are resident fish that use the mainstem
as a migratory channel to tributary spawning
habitat and as overwi nteri ng habitat.The move-
ment from tributaries to the mainstem for over-
wintering is inferred from capture data gathered
duri ng the fall and spring near tributary
mouths.
Mainstem habitat in this reach provides possible
spawni ng habitat for at 1east three species:
Beri ng ci sco,eul achon and bu rbot.Al though
spawning activity by Bering cisco may occur
throughout the reach between RM 30 and RM 100,
three spawning concentrations were identified
(see Section 2.2.1(b)[i]).Bering cisco spawning
substrates were composed primarily of 1-to
3-inch (2.5-to 7.5-cm)gravel.
Burbot and longnose sucker a re present in the
mainstem throughout the year and utilize the
mainstem for overwintering,spawning,and juve-
nile rearing.Habitat utilization within the
mainstem is probably similar to that previously
discussed for the reach of mainstem between Devil
Canyon to Talkeetna.
E-3-64
C'7""'1
2.2 -Species Biology and Habitat Utilization
"""
-
r~
I
,...,
(i i )Slough Habitat
During periods of low flow,the sloughs below
Talkeetna are primarily fed by tributaries and ground
water upwelling and carry clear water.At high
flows,the sloughs are essentially overflow channels
for the mai nstem,and the water in the sloughs be-
comes quite turbid as it assumes the characteristics
of the mainstem water.Slough water clears as the
mainstem stage drops and turbid water no longer
enters the upstream end.Hi gher vel ociti es associ-
ated with higher flows act to flush fine sediments
from the sloughs.Backwaters are created at slough
mouths when the river stage is high,but disappear at
low flows.
-Species Occurrence and Relative Abundance
•Sal mon
Chum,sockeye,and pink salmon adults were ob-
served in sloughs in this reach of the river
(ADF&G 1981b).No estimates of relative abun-
dance were made of the sal mon usi ng th'e slough
habitat in this reach.
Juvenile salmon occurrence and relative abundance
in slough habitat is similar to that reported for
the Devil Canyon to Talkeetna reach.Ch i nook
juveniles are relatively abundant in slough habi-
tat during winter and less abundant during
summer.Juvenile coho are less abundant in
slough habitat than in tributaries in this reach
throughout the year (ADF&G 1981d)•
•Resident Fish
Occurrence and relative abundance of adult resi-
dent species in this reach of slough habitat is
similar to that discussed for the Devil Canyon to
Ta 1keetna reach.The majori ty of resi dent spe-
cies are present,and relative abundance is
highest beginning in late summer and continuing
throughout the winter.Adult residents that are
most abundant in slough habitat during summer
include burbot,longnose sucker,and rainbow
trout (ADF&G 1981e).
E-3-65
2.2 -Species Biology and Habitat Utilization
Previous
whitefi sh,
abundant in
1975).
studies indicated that juvenile
grayling,and rainbow trout were
the slough during late summer (Friese
-Significance of Slough Habitat
•Salmon
Based on spawning surveys upstream from
Talkeetna,slough habitat in this reach probably
serves as spawning habitat for chum,sockeye,and
pink salmon.Factors that may contribute to the
suitabil ity of sloughs as spawni ng habitat are
the same as previously discussed for the Devil
Canyon to Talkeetna reach.
Slough habitat also serves as important rearing
and overwinteri ng habitat for juveni le chinook
and coho salmon.The importance of sloughs as
juvenile overwintering and rearing habitat may be
related to factors discussed previously for the
Devil Canyon to Talkeetna reach •
•Resident Species
The significance of slough habitat downstream
from Talkeetna to resident fish is similar to
that discussed for the reach between Devil Canyon
to Talkeetna.Slough habitat in this reach is
utilized as overwintering habitat for adult rain-
bow trout,grayling and whitefish;year-round
habitat for adult burbot and longnose sucker;and
as rearing habitat during late summer for juve-
nile whitefish,grayling and rainbow trout.The
importance of sloughs as overwintering habitat is
related to the same factors as discussed previ-
ously for juvenile salmon species in the Devil
Canyon to Talkeetna reach.No spawning sites
were observed in the sloughs of this reach (ADF&G
1981e).
(iii)Tributary Habitat
-Species Occurrence and Relative Abundance
Sa 1mon
All of the salmon species present in the Susitna
drainage were observed in tributaries down-stream
E-3-66
,~
-
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2.2 -Species Biology and Habitat Utilization
from Talkeetna.Results of previous studies by
ADF&G (1980a,1980b)and the 1981-1982 surveys in
the tr'ibutari es downstream from Tal keetna i ndi-
cate that the highest level of spawning for all
salmon species "in this reach occurs in the
tributaries.
Species occurrence and relative abundance of
juvenile salmon in the tributaries or at tribu-
tary mouths varies by season and by species.
Results of studies to date indicate:
Juvenile chinook salmon are most abundant at
tributary mouth sites during summer;tributary
sites accou nted for 95 percent of all ju ve-
niles captured in this reach.During winter,
juvenile chinook were less abundant in the
tributaries,but were captured near tributary
mouths.
Juvenile coho were relatively abundant at
tributary mouth sites during both summer and
winter •
•Resident Species
All resident species except for burbot,longnose
sucker,and lake trout were most abundant in and
at the mouths of clear-water tributaries during
summer.Information on winter distribution and
abu ndance i ndi cates that few res i dent fi sh
overwinter in tributary habitat.
-Significance of Habitat
•Salmon
Tributary habitat serves as the primary s pawni ng
habitat for all salmon species occurring in this
reach.
Based on escapement counts and population esti-
mates at monitoring stations along the mainstem,
tributaries in this reach provide the majority of
spawning habitat for.chinook,coho,and pink
salmon in the Susitna drainage.
E-3-67
2.2 -Species Biology and Habitat Utilization
Other Susitna River investigations have revealed
that all adult salmon mill to some degree in the
mai nstem and that it is not uncommon to fi nd
adult salmon in the mainstem well upstream from
their spawning destination (ADF&G 1974,1975).
Tributary habitat in this reach also supports
reari ng and summer feeding habitat for juvenile
chinook and Coho salmon.Sites associated with
tributary mouths appear to provide particularly
important rearing areas for juvenile chinook and
coho salmon.Occurrence of age 0+coho was par-
ticularly high at tributary mouth sites duri ng
summer.In addition,tributary mouth sites in
these reaches appeared to provide overwintering
habitat for juvenile coho salmon •
•Other Anadromous and Resident Species
Tributary habitat in this reach,similar to the
Devil Canyon to Tal keetna reach,apparently pro-
vides spawning habitat,juvenile rearing areas,
and summer feeding habitat for rainbow trout,
arctic grayling,round whitefish,and Dolly
Varden (ADF&G 1981e).In general,these fish
migrate during spring (early fall for Dolly
Varden)from the mai nstem or slough habitat to
clear-water tributaries to spawn.Once spawning
is completed,fish move into favorable tributary
habitat for rearing and summer feeding.As
freezeup begins,fish migrate from tributaries to
the mainstem or deeper pools near the mouths of
tributaries.Habitat characteristics that in-
fluence grayling distribution and abundance with-
in tributary habitat are discussed for the
impoundment reach in Section 2.2.1(c)(iii).
2.2.3 -Streams of Access Road Corridor
(a)Stream Crossings
The access road to the Watana and Devil Canyon damsites will
depart from the Denali Highway and proceed south to Watana
(see Plate F-32,Exhibit F).From there,the road will tra-
verse the north side of the Susitna River to the Devil
Canyon damsite.A railroad spur from Gold Creek will con-
nect to Devil Canyon.The access road corridor,including
that portion of the Denali Highway to be upgraded as part of
the project,contains at least 45 streams and rivers in both
the Nenana and Susitna River drainages (Tables E.3.19 to
E.3.21).
E-3-68
~'.
-i
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2.2 -Species Biology and Habitat Utilization
The portion of the Denali Highway between Cantwell and the
Watana Access Road crosses 10 streams in the Jack River and
Nenana River drainages (Table E.3.18).Fish species present
in Jack River or Nenana River include grayling,northern
pi ke,burbot,whitefi sh and scu1 pi n.Of these,the tri bu-
tary streams would contain at least grayling and sculpin.
From the Dena1 i Hi ghway to Watana,the road wi 11 cross Li 1y
Creek,Seattle Creek,and Brushkana Creek,as well as
numerous unnamed streams (Table E.3.20).These streams are
tributaries of the Nenana River,which supports populations
of gray1 ing,northern pike,whitefish,burbot,and sl imy
sculpin in this reach.Tributary streams are assumed to
contain at least grayling and sculpin •.
The upper reaches of Deadman Creek will also be crossed by
the Watana acc.e.ss road.Thi s creek is a tri butary of the
Susitna River and is considered important grayling habitat~
Between the Watana and Devil Canyon dams ites,the access
road will cross Tsusena·and Devil Creeks (Table E.3.21).
The streams contain grayling and may contain cottids,white-
fish,10ngnose sucker and Dolly Varden.
The road will cross the Susitna River approximately 2 miles
(3 km)below the Devil Canyon damsite.Salmon and probably
grayling,whitefish,cottids and 10ngnose sucker occur in
the vicinity of the crossing.The habitat in this reach of
the Susitna is considered relatively non-productive compared
to reaches farther downstream.
The rail road between Devil Canyon and Go1 d Creek will cross
Jack Long Creek and Gold Creek (Table E.3.21).Jack Long
Creek contai ns small numbers of pi nk,coho,chi nook,and
chum salmon (Figure E.3.17).Gold Creek has been documented
to contain .chinook,and a few coho,and pink salmon (Figure
E.3.16).Three unnamed tributaries of the Susitna River
will also be crossed.These most likely do not contain fish
because of their steep gradients,but they are considered
important sources of clear water to Sloughs 19 and 20,which
are salmon spawning areas (Figure £.3.16).
(b)Streams Adjacent to Access Corridors
In addition to crossing streams,the Watana access road will
parallel some streams,particularly Deadman Creel<.The
fisheries resources are described in Section 2.3.1(a)above.
Devil Creek will also be paralleled by the access road while
the railroad between Devil Canyon and Gold Creek will
parallel Jack Long Creek.
E-3-69
2.2 -Species Biology and Habitat Utilization
2.2.4 -Streams of the Transmission Corridor
Transmission lines will be built from Watana and Devil Canyon to
Gol d Creek and from there to Anchorage and Fa i rbanks.From
Watana to Gold Creek,the transmission line route is within 1
mil e (1.6 km)of the Devil Canyon access road except near the
Watana Dam.At Gold Creek the transmission lines will use the
same right-of-way as the Anchorage-Fairbanks Interti~,which
extends from Willow to Healy.
Resources of the Intertie are described in Commonwealth et ale
(1982).At least 27 major salmon streams,including Willow
Creek,Kashwitna River,Talkeetna River,Chulitna River,and
Indian River will be crossed by the intertie and,presumably,by
the additional lines to be built in the right-of-way in conjunc-
tion with the Susitna Hydroelectric Project.The streams contain
grayling,rainbow trout,Dolly Varden,and cottids in addition to
salmon.
South of Willow,the transmission line will be routed between the
Susitna River and the Parks Highway for much of its length.It
will cross Fish Creek and the Little Susitna River as well as
many unnamed streams (Table E.3.22).The Little Susitna is a
productive fish stream and contains coho,pink,chinook,chum,
and sockeye salmon,as well as rainbow trout,Dolly Varden,and
grayling.Fish Creek is known to support chinook,sockeye,pink
and coho salmon,and rainbow trout.Many of the unnamed tribu-
taries to the Susitna River most likely provide salmon spawning
habi tat.
An underwater crossing w11 be used to cross the Kni k Arm.The
transmission line will then proceed east and south to the
University power substation.Knik Arm serves as a migration
corridor for five species of Pacific salmon as well as other
anadromous species such as Dolly Varden,Bering cisco,eu1achon,
and lamprey.The transmission line will skirt Otter Lake,which
is stocked with rainbow trout,and will cross Fossil and Ship
Creeks.Fossil Creek is not considered a fish stream.Ship
Creek supports populations of pink,chum,coho,sockeye,and
chinook salmon as well as Dolly Varden and rainbow trout,but
because of the heavy development along its reaches,it is not
considered prime fish habitat.Planned construction of a diver-
sion wier for a power plant intake will block upstream movements
of anadr~omous fish prior to construction of the transmission
line.
North of Healy,the transmisson line will cross at least 50
creeks and rivers including the Nenana and Tanana Rivers
(Table E.3.23).These are two of Alaska's major rivers and
provide habitat for salmon,grayling,whitefish,suckers,burbot,
E-3-70
-
-
2.3 -Anticipated Impacts to Aquatic Habitat
cottids,northern pike,and inconnu.Panguinge Creek has been
documented to contain coho salmon,Dolly Varden and grayl ing
(Tarbox et al.1978).The streams in the Little Goldstream
vi ci ni ty are not cons i dered to be important fi sheri es habitat
because of their step gradients.While many of the streams go
dry in the summer,some do support grayl i ng popul at ions nea r
their mouths (Table E.3.23).
2.3 -Anticipated Impacts To Aguatic Habitat
Construction and operation of the proposed Susitna Hydroelectric
Project would result in both beneficial and detrimental impacts on the
aquatic habitat and associated fishery resources in the Susitna basin.
Many of the potenti al adverse impacts can be avoi ded .or mi nimi zed
through design and/or operation of the project,as described in Chapter
3,Section 2.4.This section examines the potential effects of the
project as proposed in Exhibit Aand addresses the impacts likely to be
sustained as a result of project construction,reservoi r fill ing,and
operation of Watana and Devil Canyon dams.Since the project is a
staged development,impacts to the aquatic habitat are presented by
project stage,phase,and river segment.The discussions focus on
important anadromous and resident species.
In this section,the term "impact"refers to a change affected on a
fish population or on its capability to utilize aquatic habitats,
resulting from project-induced changes in the physical characteristics
of the environment.Impacts refer to changes or effects that are both
beneficial and detrimental to rish populations.The project may alter
physical characteristics of the aquatic environment that do not affect
fishery resources,and therefore,these changes are not considered to
be impacts to the resources.
The description of impacts presented below is based on all available
data through spring 1982 including a significant portion of the data
from the summer 1982 field program.The types of impacts that have
occurred at similar projects have also been considered when describing
the probabl e impacts thi s project will have on the fi shery resources.
The di scuss i on represents the present understandi ng of the physi cal
processes,habitat relationships,and likely response of fishery
resources.The quant itat ive estimates of impacts presented in thi s
section will be refined as more site-specific data becomes available
from ongoing field programs.Data collection and analysis programs
currently planned or in progress will provide the information necessary
for a more refined quantitative impact analysis and mitigation plan.
The majority of the anti ci pated impacts result i ng from the constructi on
and operation of the two dam development wilT occur during the first
phase of the development,the Watana Dam.Additional impacts but of a
significantly lesser magnitude would be sustained as a result of the
addition of the Devil Canyon Dam.The Watana Dam will be constructed
first and will alter the character of the aquatic environment
E-3-71
2.3 -Anticipated Impacts to Aquatic Habitat
downstream from RM 238,the uppermost extent of the reservoi r.The
magnitude of change in aquatic habitats below the damsites decreases as
the distance from the damsites increases.Alteration of the character
of existing aquatic environment would be most notable within the
impoundment and the 53-mile (88.3 km)reach between the Devil Canyon
damsite (RM 152)and Talkeetna (RM 99).Lesser changes are anticipated
in the 99-mile (165-km)reach from Talkeetna to Cook Inlet (RM 0).
Most of the potential impacts to aquatic habitat that arise from dam
construction will be avoided through careful design and siting,and by
employing good construction practices.
2.3.1 -Anticipated Impacts to Aquatic Habitat
Associated with Watana Dam
(a)Construction of Watana Dam and Related Facilities
Potenti al impacts to aquati c habitat assoc i ated with the
construction of Watana Dam and related facilities can be
divided into three categories:
-Effects of permanent or temporary alterations to water
bodies,i.e.,dewatering,alteration of flow regime,or
alteration of channels;
-Effects on water quality i.e.,changes in temperatu re,
turbidity,nutrients,and other water chemistry
parameters;and
-Effects,both direct and indirect,on fish population.
Table E.3.23 summarizes a number of the individual construc-
tion activities that would occur during the construction
period.
(i)Watana Dam
The period of construction considered for the pro-
posed Watana Darn consists of those activities occur-
ring from initial site preparation to the start of
reservoir filling.The proposed dam will consist of a
fill structure constructed between RM 184 and RM 185
of the Susitna River.The fill will be approximately
0.75 mile (1.3 km)wide,0.75 (1.3 km)mile long and
885 feet (267 rn)high.Over 63 mill i on cubic yards
(47,880,000 m3 )of material will be used to con-
struct the dam.
Pri or to construct i on of the rnai n fi 11 structure,
access wi 11 be compl eted;the di versi on tunnel sand
cofferdams will be completed and the river diverted
E-3-72
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~,
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-
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2.3 -Anticipated Impacts to Aquatic Habitat
through the tunnels;and site-clearing activities
begu n.Heavy equ i pnent wi 11 be brought to the site,
and construction material will be stockpiled in the
project area.
The two cofferdams will surround the area of the main
dam construction.One cofferdam will be built up-
stream from the damsite and the other downstream (see
Plate F 4 in Exhibit F).The upstream cofferdam will
be approximately 800 feet (242 m)long and 450 feet
(136 m)wi de;the downstream cofferdam will be 400
feet (121 m)long and 200 feet (60 m)wide.Water
blocked by the upstream cofferdam will be diverted
into two 38-foot (U.5-m)diameter concrete-lined
tunnels about 4100 feet (1242 m)long.The
cofferdams wi 11 be constructed du ri ng a two-year
peri od (1985';'1987)and wi 11 remai n in use u nt il
reservoir'filling begins.
The construction of ·the main dam will have a number
of effects on the river and its biota.Some effects
will be the direct result of construction activities,
while other effects will result from alteration of
the river envi ronment du ri ng constructi on.Impacts
will vary in duration and overall extent,some being
temporary or localized while others will be permanent
or more'widespread..
-Alteration of Water Bodies
The greatest alteration of .aquatic habitat during
constructi on of Watana Dam will occu r at the dam-
site and at the mouth of Tsusena Creek where Borrow
Area E is located.At the construction site,the
Susitna River flows through a confined valley with
a surface width of approximately 400 feet (121 m).
The river bottom is sand,gravel and boulders.The
tributaries closest to the damsite are Deadman
Creek at RM 187 and Tsusena Creek at RM 182.Bur-
bot,sculpins,and longnose sucker probably occupy
the dams ite du ri ng the open water season and gray-
ling probably overwinter here (ADF&G 1981f).
The first major phase of dam construction involves
placement of the two cofferdams,thereby permanent-
ly dewatering 0.75 mile (1.3 km)of riverbed at the
damsite.It is anticipated that fish normally
using this stretch will move into adjacent habitats
and that the effects on population size will be
minimal.The dewatered area will eventually be
E-3-73
2.3 -Anticipated Impacts to Aquatic Habitat
covered by the Watana dam;thus,the effect will be
a permanent,but a relatively minor loss of aquatic
habitat and permanent blockage of fi sh movements·
through this reach.
Gravel mining will be an important activity asso-
ciated with construction of the dam and rel ated
fac"ilities.A large portion of the material for
the main dam will be excavated from the north bank
of the Susina River at the confluence of Tsusena
between RM 180 and RM 182.Prior to inundation,it
can be expected that some impacts to aquatic habi-
tat will occur,such as increased erosion,removal
of bank cover,ponding,dewatering,and increased
ice buildup caused by ground water overflow.In
the construction zone,Tsusena Creek is considered
more sensiti ve habitat than the mai nstem of the
Su s itna Ri ver.Ant i ci pated impacts from gravel
removal operations include increased turbidity
caused by erosion and minor instream activities,
introduction of small amounts of hydrocarbons from
equipment operating in streams and the possibility
of accidental hydrocarbon spill s.These impacts
wi 11 be temporary and are not expected to 1ast
beyond site operation.A long-term impact to
aquatic habitat is expected at the mouth of Tsusena
Creek.The volume of material to be removed will
result in a large pit that will become filled with
water.This pit will produce increased lentic
habitat in exchange for lost riparian and upland
habitat.In order to avoid impacts to the aquatic
system,borrow sites will be located,planned,and
mined in accordance with the recommendations in
Section 2.4.3(d)(ii).
During summer flood flows,the operation of the di-
version tunnels will result in increased water
levels upstream from the damsite.During winter,
the water wi 11 be ponded to an el evat i on of 1470
feet (445 m)affecting about 0.5 mile (0.8 km)of
ri ver upstream from the cofferdam.Du ri ng the
summer,a flood event equal to the once-in-50-year
flood will cause a water level of 1536 feet
(465 m),thus causing backwater effects for several
miles upstream.Water velocities within the
tunnels during operations will act as a barrier to
E-3-74
""'",
-
-.
_.
-
-
-
-
2.3 -Anticipated Impacts to Aquatic Habitat
upstream fish passage.Fish residing upstream from
the tunnels may be entrained into the flow and
transported downstream from the damsite.If river
transport mechanisms move rocks and other materials
into the tunnels,or if the tunnels are not smooth,
fish may be damaged through abrasion while being
transported downstream.
Experiments with fish transport indicate that fish
are adversely affected when exposed to vel ociti es
in excess of 9.0 ft/sec (2.7 m/sec)(Taft et ale
1975).Tunnel velocities are expected to exceed 18
ft/sec (5.4 m/sec)during much of the summer
(Chapter 2,Section 4.1.1[a]),but because rela-
tivelyfew resident fish are expected to occupy the
mainstem area immediately upstream from the tunnels
during the summer,little impact on populations is
expected (see Section 3.3.1[e]for description of
mai nstem fi sh habitats in thi s reach).To avoi d
ice problems in the diversion tunnel during the
winter,a control gate will be partially closed to
create a head pond approximately 50 feet (15 m)
deep.Entrance vel ociti es into the tu nnel are
expected to be in excess of 20 ft/sec (6 m/sec)
(Chapter 2,Section 4.1.1[a]).Grayling and other
resi dent fi sh move into mai nstem habitat to over-
winter,and physical conditions within the head
pond will provide substantial overwintering habi-
tat.Entrance velocities of 20 ft/sec (6 m/sec)
are expected to entrain fish that are overwintering
in the head pond 'into the tunnel,probably result-
ing in fish mortality.
High discharge velocities at the downstream end of
the tunnels will scour gravels,sands and silts
from the immediate area of the ttJnnel outlet.The
velocities will also deter fish from using the area
immediately downstream from the tunnel (Bates and
VanDer Walker 1964;Stone and Webster 1976).
-Changes in Water Quality
The primary change in water qual ity that is ex-
pected as a.result of Watana Dam construction is
increased turbidity.Increases in turbidity will
vary with the type and duration of construction
activity and may be of severe local consequence,
but are not expected to produce a widespread
det rimenta 1 effect upon aqu at i c habitat in the
Su sitna Ri ver system.Some of the fi rst
E-3-75
2.3 -Anticipated Impacts to Aquatic Habitat
construction activities to take place will include
clearing the areas,construction of access roads,
stockpiling of construction materials and fuel,
movement of heavy equipment,and construction of
support facilities.The construction of support
facilities and the access roads are discussed
below.
Removal of cover vegetation may result in a number
of effects.The removal of cover will increase the
local run-off causing erosion,increased turbidity,
and increased dissolved solids (Likens et al.1970;
Boreman et al.1970;and Pierce et al.1970).The
remova 1 of bank cover may also increase the expo-
su re of fi sh to predators,and 1 ead to a decrease
in fi sh popu1 ations (Joyce,et al.1980b).Tem-
peratures in local areas may also increase.
The movement of fill materials and the actual pro-
cess of construction of the fill dam will contri-
bute to turbidity and siltation.During the trans-
port,storage,and plac:,f,ent of the 63 million
cubic yards {47,880,OOO m )of fill material used
in constructing the dam,a small percentage will be
introduced to adjacent water bodies including the
rnai nstem Su sitna Ri ver through spi 11 s and erosion.
A loss of on!percent of 63 million cubic yards
(47,880,000 m)represents approximately a 25
percent increase in suspended sediment in the main-
stem of the Su sitna Ri ver.Thus,although the im-
pact on the mainstem may not be severe,the impact
on local clear-water streams could be significant.
Operation of heavy equipment in streams also in-
creases siltation and turbidity.The extent of the
impact of siltation and turbidity is dependent upon
the extent of machinery operation in the stream
beds and the substrate of the streams affected.
Fi ner substrates tend to be most affected (Bu rns
1970);but effects are also dependent upon stream-
flows in the local area.If velocities are suffi-
ciently high,deposition of suspended silts stirred
up by the machinery will not occur locally and the
effects would be minor (Shaw and Maga 1943).Since
velocities can be expected to vary seasonally,the
potential for impacts will vary seasonally as well.
E-3-76
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2.3 -Antietpated Impacts to Aquatic Habitat
Impacts caused by machi nery-i nduced s il tat i Of!and
turbidity are expected to be more temporary in
nature than those resulting from streambank clear-
i ng.
Increased turbidity generally reduces visibility
and decreases the ability of sight-feeding fish to
obtain food (Pentlow 1944;Hynes 1966),thus effec-
tively reducing feeding habitat.Most fish species
will avoid turbid areas and many salmonids avoid
spawning in turbid waters.However,increased
turbidity is anticipated to be temporary,and asso-
ciated with actual clearing or gravel removal
activities and runoff from rainfall events.
Siltation (sedimentation)is al so associated with
these activities.There is a considerable amount
of literature dealing with siltation effects on
fish (Burns 1970;Shaw and Maga 1943;Ward and
Stanford 1979)parti cul arly the effect on spawni ng
and incubation.A general conclusion reached by a
review of the literature (Dehoney and Mancini
1982)is that the greatest adverse impact of silta-
tion is on immobile eggs and relatively immobile
larval fish.In general,siltation can cause sig-
nificant losses of incubating eggs and fry in
redds,particul arly by i nterferi ng wi th oxygen
exchange.Areas of g round water upwell i ng flow
woul d tend to be a'ffected to a 1 esser extent than
other areas because silt would tend to be prevented
from settling.Only resident fish "in the vicinity
of Watana Dam,including Dolly Varden,arctic gray-
ling,and round whitefish,may be affected by sil-
tation.Entrainment of suspended materials would
also affect other water quality parameters,such as
dissolved oxygen,trace metals,and pH (Pierce et
al.1970),but is not expected to produce wide-
spread detrimental effects upon aquatic habitat in
the Susitna system.'
The production of concrete for tunnel lining,spil-
ling and powerhouse construction,and grouting will
generate concrete batching wastewater.Peters
(1978)points out that the discharge of wastewater,
if untreated,can lead to detrimental effects on
fish populations and habitat.A particular problem
with concrete wastewater is the need to adjust its
pH (10+)prior to discharge.
E-3-77
2.3 -Anticipated Impacts to Aquatic Habitat
Waterbodies can be contaminated during construction
act ivit i es by petroleum produ ct s that enter from a
variety of sources.Fuels can enter streams,lakes
and wetlands from leaks in storage tanks and pipes
and from vehicle accidents during transportation.
Poor maintenance of vehicles can also allow small
quantities of hydraulic fluid,antifreeze,and fuel
to enter water bodies.
Diesel fuel will be used and will have to be stored
in large quantities onsite.New and used lubrica-
ting o"ilswill also be commonly in use.There is a
great deal of 1iterature (USEPA 1976;AFS 1979)
describing deleterious effects caused by oil
spills.Aromatics in diesel and gasoline are par-
ticularly toxic until evaporated.Heavier oils can
coat streambeds and aquatic vegetation and inter-
fere with production of food organisms consumed by
fish (Kolpak et ala 1973).In a river as large as
the Su sitna,small spill s are expected to dilute
quickly and would likely cause harm.Spills into
smaller tributaries,especially while incubating
embryos are present,could impact resident popula-
tions.In the winter,it is difficult to recover
petroleum product spills that flow under ice in
rivers.Substantial mortal ity could result if
toxic substances reach overwintering fish and other
organisms.However,it is likely that any adverse
impacts that may occur from an oil spill would be
short-term.
Waste oils containing trace metals require handling
as a hazardous waste under 40 CFR 261-265.Sol-
vents,while probably present in much smaller
quantities than petroleum products,are usually
considerably more toxic to aquatic 1ife.Other
chemicals of concern would include antifreeze,
hydrau1 ic oil,·grease,and paints.The factors
that will affect the severity of the impact on fish
of a spi 11 are:
•The substance spilled;
•The quantity spilled;
•Frequency of spills in that area.
•The biota present;
•The life stages present;
•The season;and
Mitigation and cleanup plans and preparedness.
E-3-78
r:---",
p--,
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~,
2.3 -Anticipated Impacts to Aquatic Habitat
-Other Effects on Fish Populations
Other effects that instream construction activities
may have on fish populations include avoidance of
the area,injury,and mortal ity caused by i nstream
use of heavy equipment.Heavy equipment crossings
can also cause damage to incubating eggs and
preemergent fry if the crossing location passes
through a spawning area.
Water will be needed for production of concrete,
processing of gravel,and dust control during con-
struction.Fi sh impacts may result from entrain-
ment and impingement of juvenile fish as water is
withdrawn from local water bodies.However,
because low volume pumps equipped with proper
intake screens wi 11 be u sed,it is expected that
the number of fish affected will be low.The
potential for dewatering fish habitat in either the
summer or winter low flow period will be minimized
by pumping from streams with relatively high flow.
Current construction plans do not require instream
blasting.Blasting is planned for areas 500 feet
(150 m)or more from streams.A revi ew of the
effects of blasting on aquatic life (Joyce et al.
1980a,Appendix G)indicates that effects from such
blast i ng wou 1d probably not be 1 etha 1 (at 1 east
with charges of 1 ess than 200 kg of TNT).The
transmitted shock waves from the blasting may dis-
turb fi sh and perhaps temporarily di spl ace them
from areas near blasting activity.This type of
behavior is well documented for a variety of noise
sources (Vanderwalker 1967;Latvaitis et ale 1977;
and USEPA 1976).Secondary effects of blasting
include increased turbidity and siltation caused by
loosened soils and dust (see effects described
above).The extent of such effects would be depen-
dent upon the location and amount of blasting.
(ii)Construction and Operation of
Watana Camp,Village and Airstrips
During peak construction activity for the Watana dam,
facil iti es to hou se a maxill1Jm of 4720 peopl e are
anticipated (see Exhibit A,'Section 1.13).The
facilities ITlIst be located adjacent to the construc-
tion site to simpl ify transportation to and from the
E-3-79
2.3 -Anticipated Impacts to Aquatic Habitat
camps.Two campsites are proposed:the construction
camp will be located near Deadman Creek about 2 miles
from the dam,and the construction village will be
within a mile of the site.Each developnent will
occu py approximately 170 acres (68 ha).After the
dam is completed,a permanent townsite will be
developed that encircles a 25-acre (10-ha)lake.
The constructi on camp wi 11 contai n the management
offices,hospital,recreation hall,warehouses,com-
mu ni cat ions center,and bachelor dormitori es,among
other facilities.It is anticipated that the camp
will be dismantled at the end of Watana dam construc-
tion,to be utilized during the Devil Canyon Dam
project.The constn..lction village will be made up
of 320 temporary housing units and an additional 240
lots with utilities furnished.These temporary
housing units will be used primarily for workers who
are accompanied by families and will also be removed
when constructi on of Watana is complete.The perman-
ent town will be built to house the families of
employees who will form the operation and maintenance
team for Watana.The town will contain a hospital,a
school,gas station,fire station,store,recreation
center,and offices,as well as residences.Con-
struction of the town will not begin until the early
1990s,since it will not be needed u nt il Watana is
operational.
A 2500-foot (758-m)temporary airstrip will be built
approximately 1 mile (1.6 km)from the damsite at the
2200-2300-foot (667-697-m)level.A permanent air-
strip will be built about 5 miles (8 km)north of the
townsite.This strip will be 6000 (1818 m)feet
long.
-Alteration of Water bodies
Alteration of waterbodies resulting from the
construction of camps and related facilities will
be confined to the immediate area of the
development.Few adverse impacts are anticipated.
Gravel or other material required for facilities
constructi on wi 11 be mi ned from Borrow 5i te D.
Project facilities will be located away from water-
bodies to minimize the potential of increased
sediment input to water bodies.Overburden will be
stored in areas where it will not affect water-
bodies.
E-3-80
(
I~
2.3 -Anticipated Impacts to Aquatic Habitat
Operation of the camps and airstrips is not expec-
ted to result in appreciable alteration of water-
bodi es.The 1ake withi n the townsite may experi-
ence some continued erosion from unstabilized
building pads,but this is expected to be minimal.
Water will be withdrawn from Tsusena Creek 6 miles
(10 km)upstream from its confluence with the
Susitna River for domestic use in the camp and con-
struction village.An estimated 1.5 cfs will be
required to meet peak demands in both the construc-
tion camp and construction village.This repre-
sents less than one percent reduction in flow dur-
ing the open-water season,and little impact is
expected to result from decreases of this magni-
tude.A reduction of approximately 8 percent is
expected du ri ng the wi nter peri od.A flow redu c-
tion of this magnitude is not expected to adversely
affect fish populations.
-Water Quality Changes
Changes resulting from camp construction are expec-
.ted to be simil ar to those experi enced du ri ng dam
constructi on but much reduced in magnitude because
of the relatively great distance of the camp from
water bodies inhabited by fish.Turbidity and sus-
pended sediment levels will increase in areas where
erosion enters water bodies from such activities as
installation of the water intake system,but such
effects will be temporary.
During camp operations,the most significant im-
pacts on water quality will result from discharge
of treated wastewater into Dea~man Creek,oily and
si Tty ru noff from t he camps,water u sed for du st
control,and accidental fuel spills.
Cu rrent plans call for pumpi ng water from Tsu sena
Creek or a series of wells to supply the camps and
town du ri ng operati ons.Treated sewage du ri ng dam
construction will be discharged into Deadman Creek.
Th i s sewage system wi 11 serve both the camp and
construction village and will be used for the per-
manent town after the temporary camp and vi 11 age
are removed.The sol id waste 1 andfi 11 is situated
between the village and the camp.Fuel will be
stored within the village and the construction
E-3-81
2.3 -Anticipated Impacts to Aquatic Habitat
camp.Details of fuel storage and handling will be
developed by the construction manager in accordance
with accepted procedures.
The sewage treatment plant will include a biologi-
cal 1 agoon,whi ch wi 11 provi de secondary treatment
(Chapter 2,Section 4.1.1[g]).Secondary treatment
will avoid many of the problems associated with
primary treatment,such as decreased dissolved
oxygen and increased BOD,increased metal s,and
bacteri al counts,although it will introduce i n-
creased 1evel s of phosphorus and ni trogen -j nto
Deadman Creek (Warren 1971).Also,if the dis-
charge is treated with chemicals such as chlorine,
residual levels may have detrimental effects upon
aquatic organisms.Rainbow trout in the Sheep
River in Canada were reported to avoid areas where
chlorinated sewage effluents were discharged,and
some fish mortality resulted (Osborne et ale 1981).
Grayling,the primary species in Deadman Creek,are
considered to be very sensitive to alterations in
water quality (Carl et ale 1967).The effects of
treated discharge into Deadman Creek and thence
into the reservoir will depend upon:(1)the water
chemistry of the creek and reservoir;(2)the com-
position of the treated sewage discharge;and (3)
the dilution of the discharge within the stream.
Storm drai nage and oi ly water runoff are expected
tp occur at both the camp and the village.but will
be more of a concern at the camp,since this is
where the vehicle maintenance areas,shops,and
related facilities will be located.By providing
proper drainage facil ities.ponding areas,and if
necessary.pump stations to pump contaminated water
to the treatment facility,oily and silty water
wi 11 not reach Tsusena and Deadman Creeks.The
small 1ake within the town 1 imits will be more
susceptible than the creeks to intrusions of oily
water,storm drainage,and fuel spills.
Adverse effects may al so result from oily water
runoff from dust control on construction roads and
airstrips and from accidents involving vehicles
transporting fuels.The possible frequency and
severity of such occurrences cannot be predicted at
this time.Runoff from the solid waste landfill is
not expected to adversely impact any aquatic
habitat.
E-3-82
2.3 -Anticipated Impacts to Aquatic Habitat
-Other Effects on Fish Populations
Disruption of fish populations during camp and village
construction is expected to be limited to areas of in-
stream activity and would be simi lar to those that may
occur during construction of Watana dam or access road.
Operation of the camps will result in increased access
to an area previously exposed to minimal fishing pres-
sure.The areas expected to sustain the ·heaviest har-
vest pressure wou 1d be those stretches of Deadman and
Tsusena Creeks and the Susitna River that are easi ly
accessible from the camps and the damsite.The resident
fi sh popu 1at ions are thought to be at thei r maximum
level~l.-e.,they are at their carrying capacity (ADF&G
1981eJ.Studies to date have indicated a relatively
high percentage of "o1der"-age group fish (up to 9
years).Sportfishing will inflict heaviest impacts upon
larger,older fish and would likely result in a change
in the age distribution of the population .(Ricker
1963).
(b)Filling Watana Reservoir
Fill i ng of the Watana reservoi r wi 11 impact aquatic habitats
both up and downstream from the dam.-The 9.47 -mill i on-acre-
foot reservoi r is expected to take approximately three summer
runoff periods to fill (Table E~3.25).The length of time
requ i red to fill the Watana reservoi r depends on the amount of -
runoff that occurs during the filling period.If low-flow years
occur,filling will be extended for an additional spring runoff
period.Table E.3.26 presents the flows expected at Gold Creek
during reservoir fill ing if average flow occurs in the Susitna
River.Expected flows at Gold Creek exceed minimum target flows
proposed duri ng reservoi r fi 11 i ng ina11 but the second year of
filling,when the target flows are provided.Winter flows
(November-April)are reduced slightly in April during the first
wi nter of fi 11 i ng and are unaffected from November to Apri 1 in
the second winter1/.-
Impacts to downstream fisheries are summarized in Table E.3.27.
These habitat alterations will result in changes to all trophic
levels of the aquatic community presently functioning in the
area.
liThe effects of various mainstem flows on hydrologic characteristics
of sloughs are presented in Appendix E.2.A of Chapter 2 of Exhibit E.
E-3-83
2.3 -Anticipated Impacts to Aquatic Habitat
During filling,downstream releases will be made through one
of the diversion tunnels.The tunnels are low-level
discharge structures with limited capability to control
downstream water temperatures (Chapter 2,Sect i on
4.1.2[e][i].
(i)Watana Reservoir Inundation
Filling the Watana reservoir will inundate 38,000
acres (15,200 ha).The reservoir will flood 54 miles
(90 km)of Susitna River mainstem habitat and 28
mi 1es (46.7 km)of tri butary habitats that wou 1d be
converted from lotic to lentic systems with accom-
panying changes in hydraulic characteristics,sub-
strate,turbidity,temperature,and nutrient levels.
These habitat a lterat ions will resu 1t in changes to
all trophic levels of the aquatic community presently
functioning in the area.Figure E.3.21 shows the
area to be inundated by the Watana reservoir.
Reservoir filling will begin in May 1991 with the
spring runoff flows.The greatest changes in water
surface elevation and the most significant impacts
will occur during the first year (see Table E.3.25).
During May of the first year,the water surface ele-
vation of the reservoir will rise an average of
5 feet (1.5 m)per day reaching a depth of approxi-
mate ly 165 feet (50 m)by the end of the month (an
elevation of 1625 feet,or 492 m).Increases in
water surface elevation of 3 feet (0.9 m)and 4 feet
(1.2 m)per day are predicted in June and July,
respectively.At the end of the first year,the
reservoir will encompass an area of approximately
13,000 acres (5200 ha).It is expected to have a
surface elevation of 1875 feet (568 m)and depths of
425 feet (128.8 m).
-Mainstem Habitats
Impoundment of the Susitna River by Watana dam
will alter the physical characteristics of mainstem
habitats and consequently affect the associated
fishery resources.Burbot,longnose sucker,and
whitefish generally occupy mainstem habitats year-
round.Arctic grayling use mainstem habitats for
overwintering (ADF&G 1981f).Mainstem habitats
would be eliminated by the impoundment and replaced
by a reservoir environment.The expected physical
characteri sti cs of the reservoi r are presented -j n
Chapter 2,Section 4.1.1.
E-3-84
.....
-
2.3 -Anticipated Impacts to Aquatic Habitat
At present~mainstem habitats are utilized by bur-
bot du ri ng the open-water season.Longnose sucker
and whitefi sh generally occu py mai nstem habitats
only in the vicinity of tributary mouths (ADF&G
1981f).Burbot~longnose sucker~and whitefish are
found in glacial lake environments in south-central
and southwestern Alaska (Bechtel Civil and
Minerals~Inc.1981;Russell 1980).Since these
fish are associated with habitats similar to those
that will be present "in the reservoir~conditions
wi thi n the reservoi r du ri ng fi 11 i ng are not
expected to adversely affect these species.Thus~
these species are expected to utilize the reservoir
habitats year-round after the reservoir is filled.
White.fish and burbot spawning areas may be located
in mainstem habitats near tributary mouths.These
areas will be inundated during the first year of
filling~eliminating their present value as spawn-
ing areas.Since the habitat in the vicinity of
tributary mouths would be changing rapidly~it is
unlikely that stable spawning areas (similar to
those presently existing)would develop during
reservoir filling.The loss of spawning habitat is
expected to adversely affect bu rbot and whitefi sh
production in the proposed impoundment.However~
since the water surface elevation during reservoir
fi 11 i ng remai nsconstant from November through
April~the spawning and incubation periods for both
burbot and whitefish~any spawning that does take
place would probably be successful.
Water depth~water quality~and food avai,lability
are critical factors associated with overwintering
habitat (Bustard and Narver 1975;Tripp and McCart
1974;Tack 1980).The reservoir is expected to
provide adequate depth and water quality conditions
for overwintering fish.At the end of the first
year of filling~water depths would exceed 400
feet.Turbidity levels of the impoundment are
expected to be suitable for fish~although slightly
higher than existing winter turbidity levels in the
mainstem Susitna River.Particles less than 5
microns in diameter are expected to remain in sus-
pension (Chapter 2~Section 4.1.2 [e][iiiJ).
Studi es report fi sh overwi nter in 1 ake habitats
with suspended glacial flour levels similar to and
greater than those expected for the Watana reser-
voir (Russell 1980;deBrugn and McCart 1974).When
E-3-85
2.3 -Anticipated Impacts to Aquatic Habitat
fill ed,the reservoi r wi 11 have a surface area of
approximately 38,000 acres (15,200 ha),which
greatly increases the amount of habitat having
suitable conditions for overwintering fish.The
increase in overwintering habitat may have a
beneficial impact on fish resources of the upper
Susitna basin above the Watana dam,if lack of
available overwintering habitat presently 1 imits
fish populations in the area.
Winter reservoi r water temperatures may increase
the quality of overwintering habitat in the upper
Susitna Bas in.Reservoi r temperatures in the top
100 feet (30 m)are expected to be in the range of
1 to 2°C (33.8 to 35.6°F)(Chapter 2,Section
4.1.3[e][i]).Present winter water temperatures in
mainstem habitats in the proposed impoundment area
are near aoc (32°F).These warmer water tempera-
tures may benefit fish by increasing the overwinter
survival rate.During the winter of 1981-1982,
fish apparently sought out water with warmer tem-
peratures in the lower Susitna River.Other inves-
tigators have reported that fish prefer warmer
water areas in the winter (Umeda et al.1981).
-Tributary Habitats
Filling the Watana reservoir will inundate portions
of six tributaries (Table E.3.28):Deadman,
Watana,Kosina,Jay,and Goose Creeks and the
Oshetna River (Figure E.3.21).All of these tribu-
taries support grayling populations,and grayling
that depend on habitats inundated by the reservoir
will be displaced and may be lost.
The initiation of reservoir filling in May 1991
coincides with grayling spawning activities.In
the project area,arctic grayling spawn in the
clear water tributaries during spring breakup,and
the embryos take approximately 11 to 21 days to
develop (Morrow 1980).Most of the spawning activ-
ity appears to take place in the lower portion of
the tributaries.Spawning areas in the six streams
will be inundated in May and June of the first year
of filling.The water surface elevation is fore-
cast to increase at a rate of 5 feet (I.5 m)per
day duri ng the spawni ng peri od,with increases of
3 feet (0.9 m)per day during the latter part of
the incubation period.
E-3-86
-
-
-
-.
2.3 -Anticipated Impacts to Aquatic Habitat
During the grayling spawning period,streams gene-
rally carry increased sediment loads from high
spring flows and ice breakup.The sediments
carried by the stream will be deposited at their
confl uence with the reservoi r as a result of the
reduced stream velocities associated with backwater
conditi ons.The resultant sedimentati on will de-
posit on the spawning bed,and embryos on the
stream bottom will likely be covered with sediment
and suffocate.Longnose sucker may spawn in tribu-
tary mouths during the spring (ADF&G 1981f),and
they are expected to experience the same effects as
grayling.
Arctic grayling depend on tributary habitats for
summer rearing areas.Grayling are not expected to
occupy reservoir habitats during the summer as they
are not found in lake habitats with turbidity
levels similar to those projected to occur in the
reservoir (Russell 1980)(see Chapter 2,Section
4.1.2[e][iii]for projected impoundment turbidity
levels).Grayling densities in tributaries are
high,averaging 323-1835 fish per mile in 1982
(Table E.3.17),which indicates that available
summer habitats are occupied (ADF&G 1981f,1982e).
Grayling occupying tributary habitats inundated by
the reservoi r will 1ikely be lost because of lost
feeding habitat.A small percentage of these gray-
1 ing are expected to remain in the reservoir near
tributary mouths.
Approximately 2.3 mil es (3.8 km)of Deadman Creek
will be inundated by the reservoi r at full pool.
Presently,a waterfall located about 1 mile
(1.6 km)upstream from the mouth prevents upstream
fish migration.The reservoir will inundate this
barrier and allow fish passage to the upper Deadman
Creek and Deadman Lake.Since the available limit-
ing habitats in Deadman Creek are presently occu-
pi ed by g rayl i ng,thi sis not expected to cause
significant increases in the populations.
Dolly Varden will be only slightly affected by the
inundation.Dolly Varden occupy a wide range of
habitat types in south-central Alaska including
glacial lakes with a wide range of water quality
(Russell 1980).In the project area,Dolly Varden
are residents occupying tributary habitats during
E-3-87
2.3 -Anticipated Impacts to Aquatic Habitat
the open-water season and after spawning return to
the mainstem to overwinter.It is anticipated that
Dolly Varden wi 11 occupy reservoi r habitat year-
round.
Dolly Varden spawn in the fall,the embryos incu-
bate through the winter,and the alevins emerge in
the late spring.Since the reservoir is not fil-
ling during the spawning and incubation period,any
spawning areas available in the fall would not be
affected before emergence.
-Lake Habitats
Sally Lake (FigureE.3.21)and several other small
lakes will be inundated by the reservoir.Sally
Lake has populations of lake trout and grayling
that appear to be stunted (ADF&G 1981f).Si nce
grayling populations are not usually associated
with glacial lakes or turbid water,the grayling
population will likely be lost.Lake trout will be
able to survive in the reservoir if an adequate
food base exists.Lake trout are found in gl aci al
1 akes,i nc1 udi ng Chakachamna and Kontrashi buna
Lakes (Bechtel Civil and Minerals,Inc.1981 and
Russell 1980),with physical characteristics simi-
lar to those expected in the Watana reservoir.
(ii)Watana Dam to Talkeetna
Table E.3.26 presents a comparison of average monthly
pre-project flows and projected monthly flows at Gold
Creek during initial reservoir filling.The greatest
change to the system wi 11 occur duri ng the summer
season.The filling phase of the Watana development
will alter streamflows,water quality,and water tem-
peratures downstream from Watana dam to Talkeetna
(Chapter 2,Section 4.1.2).The second open-water
season of filling (May 1992 through October 1992)is
scheduled for minimum releases and is thus discussed
below as maximum expected impact,unless otherwise
noted.
-Mainstem Habitats
Mainstem habitats in this reach can be divided into
two segments:from Watana Dam to RM 152 in Devi 1
Canyon and from RM 152 to Talkeetna (RM 99).High
velocities associated with natural flows through
E-3-88
P"'\
2.3 -Anticipated Impacts to Aquatic Habitat
Devil Canyon normally appear to prohibit upstream
passage of fi sh beyond RM 152.Thus,anadromous
fish are prevented from using habitats upstream
from the canyon except during dry years when flows
are 12,000 to 15,000 cfs or less.During 1982,one
of the driest summers on record,chinook salmon
ascended to RM 156.8 but were not reported upstream
from that point.
During the open-water season (June through October)
mainstem habitats below Devil Canyon are primarily
used as a migratory corridor by adult and juvenile
fish as they move to and from spawning and rearing
areas that are located in other habitat types asso-
ci ated with the river.A few i sol ated salmon
spawning areas have been identified in the mainstem
(ADF&G 1981b,1982e).Some juvenile salmon rear in
this hab.itat type in low densities during most of
the open-water season.Juvenile salmon from other
rearing areas and resident fish move into mainstem
habitats for overwintering as the river clears in
late fall (ADF&G 1981d,1981e).Several resident
species,including burbot,whitefish,and longnose
sucker,occupy mainstem habitats year-round (ADF&G
1981e).Upstream from Devil Canyon,mainstem habi-
tats are used by burbot,sculpin,longnose sucker,
and whitefish year-round and by arctic grayling for
overwintering habitat (ADF&G 1981f)•
•Altered Flow Regime
A variety of changes will occur in mainstem
habitats as a result of the proposed Watana
reservoir-filling schedule.Flows will be sub-
stantially reduced during the spring period.
With the exception of the first year,average
monthly flows in May and June will be reduced to
approximately 6000 cfs from pre-project average
annual flows of 13,300 and 28,100 cfs,respec-
tively (Table E.3.26).Decreases of this magni-
tude will affect the physical processes in this
reach,which in turn will affect fish associated
with this habitat type.
Filling flows during May and June will affect the
ice removal process in this reach.Presently,
the natural flows increase during May,causing a
mechanicaJ breakup of the ice cover,and rapidly
transport large chunks of ice and attached sedi-
ment downstream.The force to raise and fracture
E-3-89
2.3 -Anticipated Impacts to Aquatic Habitat
the ice cover is the resul t of ri sing stream
flows caused by rapid snowmelt and is common to
many Alaskan rivers.Under the filling schedule t
mechanical breakup will tend to be less severe in
the mainstem and unlikely to occur in side-
channel or slough habitats.Thus t ice scouring
and bank gouging would be reduced.The potential
for ice jams and resultant flooding would be
diminished (Chapter 2 t Section 4.1.2[e][ii]).
Outmigration of salmon fry and smolts generally
occurs in June t apparently on the receding limb
of the high spring flows.Flows of 6000 cfs
would not affect downstream migrations in main-
stem habitats because sufficient depth and velo-
cities would exist to transport fry or smolts.
Predicted depths and velocities at all 65 sur-
veyed cross-sections between Devil Canyon and
Talkeetna indicate that at 6000 cfs t minimum
depths would exceed 2 feet (0.6 m)(Figure
E.2.10).
Flows of 6000 cfs would persist until the last
week of July.Chinook salmon are passing through
the system in late June and July to spawning
habitats in tributary streams.These fish hold
in mai nstem areas to mature before mavi ng into
the tributaries (ADF&G 1981b).Many of the hold-
ing areas available at flows of 20.000 cfs would
probably not be available at 6000 cfs.however.
other suitable holding areas are expected to
exist under the low-flow conditions resulting
from filling the reservoir.
Duri ng June and July of the second and thi rd
years of filling,flow velocities in Devil Canyon
are not expected to block all upstream fish
passage.Chinook salmon would likely be able to
pass through the canyon and utilize spawning
habitat avail abl e in tri butari es upstream from
Devil Canyon and below Watana Dam.Tel emetry
studies located chinook salmon in the lower Devil
Canyon reach (RM 150.4 to 151.5)in late June and
ea rly July 1982 (ADF&G 1983).In August.spawn-
ing chinook salmon were observed in the mainstem
at the mouth of Cheechako Creek (RM 152.5)and in
an unnamed creek (RM 156.8),both upstream from
the Devil Canyon damsite.High velocities
blocked migrations past RM 156.8 (ADF&G 1982d).
E-3-90
,---
r-·-~·-"I
-.
.~
2.3 -Anticipated Impacts to Aquatic Habitat
According to 1982 USGS provisional streamflow
data,now levels dropped to 17,000 cfs at Gold
Creek in early July,then rose to 25,000 for the
remainder o.f the month.Since the telemetry
studies located chinook salmon just downstream of
Devil Canyon in late June,the salmon probably
passed through the canyon in ea r1y July when the
flows had dropped.High nows in 1981 prevented
them from migrating past RM 151.7 (ADF&G 1981b).
With the filling now of 6000 cfs in June and
July,the entire canyon is expected to be
passable by chinook $almon,allowing them to
enter Tsusena,Fog,and Devil Creeks (RM 178.9,
173.9,and 161.0).
Pink,chum,and coho salmon spawning areas in the
mainstem are expected to be adversely affected by
the flows proposed in the filling schedule.
These spawning areas are generally small,iso-
lated areas on the river margins or behind veloc-
ity barriers (ADF&G 1981a,1983).Lateral areas
are more susceptible to changes in now.The
qual ity of these habitats wi 11 be degraded
through reduced depth and velocity;some areas
may be completely dewatered.
Fall n ows at Go1 d Creek drop rapidly under the
filling schedule (Table E.3.26).Under the fil-
ling nows,the river would reach 2000 cfs in
October,whe reas flows of 2000 cfs do not nor-
mally occur until November.In addition,the
entire ice formation process will be delayed 3 to
4 weeks 1ater than normal,and the stagi ng wi 11
be less than normal.Thus,the stage during
filling in October would be reduced,decreasing
the wetted perimeter.Spawning areas of summer
and fall spawning fish,such as salmon and white~
fi sh,a re expected to be adversely affected by
recedi ng flows •
•Altered Temperature Regime
Since the diversion tunnels will function as 10w-
l~vel intakes,the thermal regime of the Susitna
River from Watana Dam to Talkeetna will be
altered (Chapter 2,Section 4.1.2[e][i]).Down-
stream water temperatures during the first open-
water period of reservoir filling (May through
E-3-91
2.3 -Anticipated Impacts to Aquatic Habitat
October)will be similar to pre-project tempera-
tures,with some lagging.During fall,the
reservoir will retain heat longer and will gradu-
ally cool to 4°C (39.2°F).Winter temperatures
above Devil Canyon are expected to range from 2
to 4°C (35.6°to 39.2°F).When the water reaches
RM 160,water temperatures are expected to be
near O°C (32°F)(pre-project levels).
Temperatures during the second open-water season
will be substantially reduced.Water released at
Watana Dam will be approximately 4°C (39.2°F).
Because of the large water volume (12,000 cfs in
August)and the high average water velocities
(3-4 ft/sec or 0.9-1.2 m/sec),water temperatures
during August are expected to be in the range of
5°to 6°C (41°to 42.8°F)at Talkeetna.At the
beginning of the third year of filling,the
reservoir water surface elevation is expected to
be 2083 feet (631.2 m),high enough to util ize
the multiple level intake structure (Figure
E.2.105).This will provide sufficient control
to release water near lOoC (50°F)during July,
August,and early September (Figure E.2.174).
Lower water temperatures during the second season
of filling may adversely affect fish populations
in the reach from Watana Dam to Talkeetna.Pro-
j ected water temperatures of 5°to 6°C (41 °to
42.8°F)are well below normal water temperatures
of 10°to 12°C (50°to S3.6°F)in August.Under
natural conditions,pink salmon have been repor-
ted to migrate at 5°C (41°F)in Russia,while 7°C
(44.6°F)is the lowest reported mi grat i on tem-
perature below SOON 1atitude (Bell 1983).For
coho salmon,4°C (39.2°F)is the lowest recorded
temperature at migration in northern stocks,
while 7°C (44.6°F)is the lowest temperature
below SOON latitude.In the Columbia River,coho
movements ceased at approximately 6°C (42.8°F)
(Bell 1983).In northern areas,chinook have
been reported moving at 4°C (39.2°F),sockeye at
2.5°to 4°C (36.5°to 39.2°F),and chum at 1.S o C
(34.7°F).These observations are not directly
applicable for predicting the impacts associated
with the temperature reduction during filling
since they represent natural migrating tempera-
tures.Salmon returning to the Susitna River
will begin migrating in the near-normal tempera-
ture regime in the lower river and then encounter
E-3-92
r=-,
-
--
i"
i
2.3 -Anticipated Impacts to Aquatic Habitat
reduced temperatures at Talkeetna.These lower
temperatures are expected to increase mi 11 ing
behavior and delay the migration into the reach
upstream from Talkeetna.Portions of some
stocks,particularly pink and coho,will likely
not enter the reach and will sel ect alternat i ve
spawning areas.For those adults that enter the
reach,the mainstem temperatures are expected to
slow the rate of migration and retard sexual
mat uri ty.These impacts wi 11 result in reduced
productivity in this reach during the second year
of fill ing.Slough and tributary temperatures
will be unaffected,so adults that reach these
normally-used spawning areas would resume natural
spawning activity.
Lower water temperatures during the second open-
water season are expected to adversely affect
resident and juvenile anadromous fish that uti-
lize mainstem and side-channel habitat.Feeding
activity!and growth are closely correl ated with
water temperature (Clarke et ale 1982).Colder
water temperatures may reduce growth during the
open-water season.Juvenile salmon have been
found to avoid cooler water when possible
(Bustard and Narver 1975).Thus,fish may avoid
mainstem and s ide-channel habitats and move to
warmer water in tributary and slough habitat.
-Side-Channel Habitats
Many of the physi cal changes i dent ifi ed for mai n-
stem habitats would also occur in side-channel
habitats.Since the side channels are generally
characterized by higher streambed elevations at
thei r upstream than the mainstem bed elevation at
that location,the forecasted changes in streamflow
are expected to cause greater effects in si de-
channel habitats.During the open-water season,
side-channel habitats are used for passage by sal-
.mon and rainbow trout;for spawning by pink,chum
and coho salmon;and for summer feeding areas by
longnose sucker,burbot,and whitefish (ADF&G
1981b,1981d,1981e,and 1983).Little juvenile
salmon rearing has been reported in side-channel
habitats duri ng the open-water season (ADF&G
1981e).
E-3-93
2.3 -Anticipated Impacts to Aquatic Habitat
As in mainstem habitats,the greatest changes would
occur in the spring because of the substantial flow
reductions from pre-project flows (Table E.3.26).
Many side channel s that normally convey water in
May,June and the first three weeks of July may be
dewatered under filling flows.
Decreased mainstem flows would l·ikely result in
decreased depths and velocities in some side-
channel habitats and complete dewatering of others.
This is expected to alter or eliminate the availa-
bility or suitability of currently used spawning
habitat.
It is unlikely that new spawning areas will become
available in side channels under the filling flows.
Side-channel habitats with a streambed elevation at
thei r upstream end that is low enough to convey
water during the reservoir filling process are
expected to have substrate that is too 1arge for
spawning.Under natural conditions these side
channels are subject to peak flows that have
removed most of the gravel substrates,1eavi ng the
streambed armored with large cobbles and boulders
(R &M Consultants 1982c).It is unl ikely that the
substrate in these areas would change as a result
of the project.Thu s,the use of these areas by
spawning fish would continue to be limited by sub-
strate.
Redu c ed flows in the s pri ng may i nh i bit emergence
and outmigration in some side-channel spawning
areas.At times,spawning areas can be substan-
tially dewatered but the embryos can be maintained
by intergravel flow that allows development to
proceed.Normally,increased spring streamflow in
these areas provi des water for emergence and Qut-
migration.Filling flows are not expected to be
sufficient to provide streamflow in some of these
areas.
Filling flows will alter the hydraulic conditions
of the side channels that are not dewatered.Lower
discharges will decrease velocities,depths,and
wetted perimeters.This is expected to improve the
quality of these areas as rearing habitat for some
resident and juvenile anadromous fish.Juvenile
fish are generally found in association with low
E-3-94
r
2.3 -Anticipated Impacts to Aquatic Habitat
velocities (ADF&G 1982,"Wilson et al.1981;and
Environaid 1982).Burbot,longnose sucker and
whitefish are also found in waters with a low
velocity,but require greater depth.
Use of these areas by juven il e salmon may be pre-
sently limited by lack of a food source.Benthic
production is limited by "the high summer turbid-
it i es and scouri ng effects of suspended sed iments.
Under filling flows,turbidity would be decreased
(Chapter 2,Section 4.1.2[e][iii]),allowing
greater light penetration;the scouring effect of
the greater pre-project flows would also be reduced
(Chapter 2,Section 4.1.2 Cd]).Some side channels
above Talkeetna will be completely dewatered under
.the proposed filling flows,thus eliminating any
rearing or feed ing habitat normally supported by.
pre-project flow levels.Benthic production from
these areas would also be lost.The increase in
production because of greater light penetration and
reduced scouring in flowing side channels isexpec-
ted to be much greater than the loss expected from
dewatering some of the side channels.
Stream temperatures during filling in side-channel
habitats wi 11 be similar to mainstem habitats (see
previous section).
-Slough Habitats
Slough habitats in the Watana Dam to Talkeetna
reach have been identified as the most important
spawning areas directly influenced by the Susitna"
River.Sockeye,chum,pink,and coho salmon have
spawned in 20 of the 34 sloughs found above the
confluence with the Chulitna River (see Figures
E.3.12 to E.3.17)•.Juvenile coho and chinook have
been found uti 1 i zi ng these areas as reari ng and
overwintering habitat (ADF&G 1981d).Rainbow
trout,burbot,longnose sucker,and wh itefi sh have
been found in these habitats at various times of
the year (ADF&G 1981e).
Sloughs in this reach of the river resemble con-
fined side channels.In general,they function as
overflow channels and convey turbid water from the
mainstem at high flows.During mainstem flows of
less than 20,000 cfs,clear water originates from
E-3-95
ground water upwelling and flows
channel into the mainstem river.
2.2.2[cJ of this chapter and
2.3 -Anticipated Impacts to Aquatic Habitat
surface runoff and
through the slough
(Refer to Section
Appendix E.2.A.)
Preliminary conclusions from a study of Slough 9 indi-
cated that ground water upwelling,and in part,flow,in
this slough is related to the stage of the mainstem
Susitna Rlver (Trihey 1982d).At the slough upwelling
locations that are within the mainstem backwater,the
ground water gradient between mainstem and slough is
relatively unaffected by discharge until backwater
effects are no longer present at the upwelling location.
Hence,upwelling rates in backwater areas would remain
virtually unchanged until the area is no longer affected
by backwater.At locations where slough upwelling is
unaffected by mai nstem backwater effects,the reduced
gradient will result in reduced slough upwelling rates.
Under reservoir filling conditions,discharge will be
reduced to about 1000 cfs at Gold Creek during the
freezeup period.This will result in reduced staging
compared with pre-project ice-staging levels.Hence,
during w"inter,the mainstem slough water level differ-
ential will be reduced with a corresponding reduction in
upwelling area.Reduced upwelling would affect the
quality and quantity of both spawning and rearing habi-
tat presently available in the systeml/.
Filling flows will cause passage problems for adult
salmon moving from the mainstem and side-channel habi-
tats into slough habitats.Based on field observations
during the low flows of August 1982,Susitna streamflows
in the range of 12,000 to 14,000 cfs,combined with
extremely low surface runoff into the sloughs,hampered
or restricted the passage of adult salmon into several
sloughs.The water depth at the slough entrance is a
function of the water surface elevation of the mainstem
and the discharge from the slough2/.An increment-
al analysis was performed on the effects of various dis-
charges on access of adult salmon into Slough 9.Data
obtalned during the 1981 and 1982 field seasons indicate
that the flow from Slough 9 is quite small unless the
mainstem has overtopped the alluvial berm at its up-
stream end (Trihey 1982d).Upstream passage into Slough
9 by adult chum salmon would not appear to be restricted
when mainstem discharges were 18,000 cfs or higher.
Access becomes
YAdditional information is presented in Appendix E.2.A .
.£/This relationship is presented in Appendix E.2.A for sloughs 8A,9,
and 21.
E-3-96·
-
-
2.3 -Anticipated Impacts to Aquatic Habitat
increasingly more difficult as mainstem discharge
decreases.An acute access problem exi sts at
streamflows of 12,000 cfs and less (Trihey 1982d).
In general,upstream access into Slough 9 is some-
what more difficult than an average entrance condi-
tion encountered by adult salmon in the Devil
Canyon to Ta 1 keetna reach.Upstream access into
Slough 9 is easier than access to Slough 16B or 19;
but more difficult than access into Whiskers Slough
or Slough 8A.It is a reasonable index of entrance
conditions into Sloughs 20 and 21 (Trihey 1982d).
Under Watana fi 11i ng condit ions,only the backwater
areas would be affected.Surface runoff,which is
controlled by rainfall,and snowmelt and ground
water upwelling contribute'to the flow in the
sloughs.The flow in the slough controls the phy-
sical characteristics of the habitat upstream from
the backwater during the open-water season.
A reduct ion in mai nstem stage may degrade and
reduce spawning habitat in the sloughs.Adult
sockeye and chum appear to seek out areas with
upwell i ng ground water in whi ch to spawn.If a
reduction in mainstem discharge reduces the amount
of upwelling or the area influenced by upwelling,
spawni ng habitat will be reduced or may be el imi-
nated.In a worst case scenario,if all upwelling
ceased such that all slough spawning was elimi-
nated,the spawning area used by approximately 3700
chum in 1982,2300 sockeye in 1981,and 740 pink,
salmon in 1982 would be eliminated (Table E.3.12).
Losses of this magnitude would reduce the total run
size by 11,840 chum;9200 sockeye and 3550 pink
salmon,assuming harvest in escapement ratios of
2.2:1;3.0:1;and·3.8:1,respectively (Friese
1975)•The sockeye that spawn in the sloughs
upstream from Talkeetna,however,are considered to
be strays from Chul itna and Tal keetna Ri ver stock
(ADF&G 1983).If this is true,and this segment of
the run is not self-perpetuating,then the run size
of sockeye would not be reduced.
Since juvenile fish occupy habitats with a rela-
tively wide range of depth,decreases in the depth
of sloughs are expected to have little effect on
the utility of rearing habitat.The greatest
impact to juvenil e habitat woul d occur if the
reduct ion in depth also el imi nates or reduces the
util ity of cover objects associated with slough
E-3-97
2.3 -Anticipated Impacts to Aquatic Habitat
habitats.In addit i on to obj ect cover,young
chinook have been observed occupying the interface
between the turbid and clear-water portions of the
backwater at the mouth of the slough.Under the
proposed flow regime during reservoir filling,the
amount of this particular habitat would be reduced
by decreased backwater effects.Additional rearing
habitat,however,is expected to become ava il ab 1e
in mainstem and side-channel habitats.(These
habitats are discussed in their respective
sections.)
The reduction of mainstem flows during the spring
and the al tered breakup process may affect out-
migration from slough habitats.It is thought that
changes in water levels and temperatures trigger
out-migration in young salmon.Fish were observed
to outmigrate on the receding edge of the high
flows in spring 1982.Under the filling schedule,
the high flows during the spring would be elimi-
nated.However,flow from local runoff woul d be
unaffected,and this flow and rising water tempera-
tures should be sufficient to stimulate fry to
out-migrate from the sloughs (Thomas 1975).
Under filling flows,increased beaver activity is
expected to have an adverse effect on adult salmon
utilization of slough habitats.The elimination of
spring breakup flows will allow beaver to become
established in most sloughs.During the low flows
of AUgust 1982,beaver dams located in Slough 8A,
inhibited use of upstream slough habitats by adult
salmon.An increase in beaver dams,however,would
increase rearing habitat for juvenile chinook and
coho.
-Tributary Habitats
Compared with other habitat types in the reach from
Watana Dam to Talkeetna,tributary habitats receive
the largest salmon escapement (Section 2.2.2(b)
[iii])of this chapter;ADF&G 1981b and 1983).
Tributaries also provide important spawning habitat
for grayling and rainbow trout and rearing habitat
for chinook and coho salmon juveniles (ADF&G 1981d
and 1981e).
With the except ion of tri butary mouths,tri buta ry
habitats below the impoundment will not be affected
by the proposed project.Seasonal vari ations of
E-3-98
17'-'
p-:r-,
.....
-
-
2.3 -Anticipated Impacts to Aquatic Habitat
the mainstem discharge changes the hydraulic
conditions associated with the tributary mouths.
During the open-water season,the present stage in
the mainstem river causes a backwater to form at
the tributary confluences.The backwater area
provides rearing habitat for resident species and
juvenile salmon (ADF&G 1981d and 1981e)and
facil itates passage of upstream migrants into the
tributary.
lower mainstem flows during filling will reduce the
backwater effects and decrease water depths at
tributary mouths.Rearing fish are not expected to
be impacted since similar backwater areas will
reform in mainstem habitats downstream from tribu-
tary mouths.
A reducti on in the stage of the mai nstem ri ver
could cause some tributaries to become perched and
impede migration by adult salmon and resident fish
to upstream areas.As the tri butary enters the
mainstem river,the change in gradient causes the
tributary water to drop transported materials.
These gravel s and sand form small deltas at the
mouths of tributaries (Figure E.2.140).As the
stage in the mainstem recedes,the tributaries
become perched above the river.Since the flow in
the tributaries is not regulated,the tributaries
would continue to experience peak high flows.In
most tributaries that support fish,these high
flows will be sufficient to down cut through the
delta material to establ ish a channel at a new
gradient (R&M Consultants 1982f).Jack Long (RM
144.8),Sherman (RM 130.9),and Deadhorse
(RM 121.0)Creeks are the only streams used by
adult salmon that may remain perched under the
proposed filling flows (R&M Consultants 1982f).
Although adult pink salmon have been documented in
Dea<:ihorse and Sherman Creeks,it is quest i onab 1e
whether wi nter flows that drop below the surface
can support successful salmon production.
An incremental analysis of access into Portage
Creek and Indian River under project operational
flows indicated that access by adult salmon is not
expected to be a problem (l:'rihey 1983).If the
tributary channels remain perched and mainstem
flows are near 8000 cfs,tributary discharge will
E-3-99
2.3 -Anticipated Impacts to Aquatic Habitat
provide sufficient depth to maintain access.Velo-
cities near the confluence of both tributaries are
also not expected to block access.It is anticipa-
ted that the t ri butari es wi 11 down cut to a new
streambed equilibrium (R&M Consultants 1982f)at a
depth approximately the same magnitude as the
difference between the water surface elevation
associated with the most prevalent summer discharge
of the mainstem.
The reduced flows through Devil Canyon will allow
chinook salmon access to tributaries upstream from.
the rapids that have historically b10cked sa1mon
migrations (see mainstem section).Under the fi11-
ing regime,chinook salmon will have access to
Cheechako Creek (RM 152.5)and the unnamed tri bu-
tary at RM 156.8 (Figure E.3.6)on an annual basis.
In addition they are expected to have access to
Tsusena,Fog,and Devil Creeks at RM 178.9,173.9.
and 161.0,respectively (Figure E.3.6).There
appears to be adequate habitat in these creeks to
allow for salmon production.Thus,the Watana
development wi 11 increase the avail abil i ty of
spawning habitat in tributaries in this reach.
Future development of the Devil Canyon dam wou1d
subsequently el iminate access to these tributa-
ries.
(iii)Cook Inlet to Ta1keetna
Project effects below Ta"lkeetna are expected to be
considerably reduced in magnitude from those pre-
sented for the Watana dam to Talkeetna reach.Just
upstream from Talkeetna,the Chulitna and Talkeetna
rivers join the Susitna River.These rivers contrib-
ute 39 and 18 percent,respectively,of the stream-
flow in this reach (R&M Consultants 1981c).Many
other major tri butaries enter the Susitna in thi s
reach (Fi gure E.3.3).In order to eval uate the
streamf1 ows in thi s reach,two streamflow stati ons,
the Sunshine and Susitna stations,were established.
Tables E.3.29 and E.3.30 present a comparison of
pre-project and proposed fill ing flow regimes for
these stations.
Si nce the project will have no effect on the tribu-
tary basins,project-related physical changes in the
Susitna River below Talkeetna will be of less magni-
tude than physical changes above Talkeetna.Impacts
E-3-100
-
2.3 -Anticipated Impacts to Aquatic Habitat
to fi sh habi t at s below Ta 1keet na a re expected to be
limited since only minor changes will occur in physi-
cal characteristics of mainstem habitats.Physical
characteristics of side channels are generally more
susceptible to changes in mainstem discharge and the
proposed fill i ng flows may affect side-channel habi-
tats.
-Mainstem Habitats
During the open-water season,mainstem habitats in
this reach of the Susitna River are used primarily
for passage and limited spawning.The reach exten-
ding from approximately RM 4.5 to RM 29 is almost
entirely eulachon spawning habitat sustaining a
spawning adult population ranging in the millions
of fish (ADF&G 1983).In addition,spawning areas
for chum salmon and Bering cisco have been located
(ADF&G 1981b,1982d,e and 1983).To date,few
reari ng fi sh have been found in thi s reach (ADF&G
1981d).Resident fish including burbot,whitefish,
and longnose sucker occupy mainstem habitats during
the open-water season (ADF&G 1981e).
Littl e change is expected in water temperature or
turbidity in this reach.The Chul itna Ri ver car-
ries a much heavier sediment load and has approxi-
mately the same discharge.as the pre-project
Susitna River at their confluence (R&M Consultants
1981d).Under the proposed filling schedule,the
water from the Susitna River would comprise approx-
imately 14 percent of the streamflow below the con-
fluence of the Chulitna and Talkeetna rivers in
July and 25 percent in August.The i nfl uence of
the Chul itna and Talkeetna rivers would dominate
the thermal,water chemistry,and suspended sedi-
ment characteri stics of the lower Susitna River
(Chapter 2,Section 4.1.2[e][iii]).
Only a small reduction in the number and magnitude
of peak flows from Talkeetna to Cook Inlet is anti-
cipated.Si nee the project control s such a small
portion of the runoff in this reach,a 1-in-2-year
flow event at Susitna Station would become a l-in-5
or 1-in-10 year event (R&M Consultants 1982).
Thus,high,turbid flows in the lower Susitna River
may still inhibit fish passage at times as well as
limit benthic production.
E-3-10l
2.3 -Anticipated Impacts to Aquatic Habitat
Under the proposed fi 11 i ng schedul e,average
monthly streamflow in July and August would be
reduced by a maximum of 28 and 17 percent at
Sunshine Station (Table E.3.29).Because of the
channe 1 geometry of the mai nstem,flow reductions
of this magnitude would probably not change the
util ization of mainstem habitats with regard to
salmon passage and resident fish summer activities.
The reductions in depth resulting from this
decrease in streamflow woul d not create passage
probl ems.Nor is it 1 i kely that summer feedi ng
areas woul d be e 1imi nated.Flow reducti ons may
have a more significant effect on spawning habitat,
since this habitat tends to be located on the
lateral margins of the mainstem and in side channel
a rea.
Most salmon-spawning areas in the mainstem are
located in broad or braided segments that are more
sensitive to changes in flow.Small changes in
stage near the threshold value necessary to overtop
the upper end of the braided channels can poten-
tially result in large changes in the availability
of spawning areas within the braided area.
Salmon and Bering cisco spawning habitats may be
subject to greater changes,since they occur
primarily in the upper portion of this segment from
RM 75 to 81 (ADF&G 1982a and 1983).Beri ng ci sco
spawned in mai nstem habitats from RM 75 to RM 81
during October 1981 (ADF&G 1982b,and 1983).Dur-
ing filling,October flows would be reduced by 9
percent the second year and by 26 percent the third
year at Sunshine Station (Table E.3.29).Reduc-
tions 1ess than 10 percent are not expected to
impact fi sh as changes in depth a nd vel oci ty are
small.Reductions of 26 percent may reduce Bering
cisco spawning habitat.
Eulachon spawning areas would be subject to the
least amount of change,since they occur in the
lower part of the reach,RM 4.5 to 58 (ADF&G 1982d
and 1983).Eulachon spawning areas were identified
by ADF&G duri ng spawni ng surveys in May 1982 in
areas adjacent to cut banks and riffle zones or
bars with moderate velocity where the substrate
included deposits of unconsolidated sands and gra-
vels.Because of the channel geometry in the
E-3-102
p'-
....
....
2.3 -Anticipated Impacts to Aquatic Habitat
broad,braided floodplain of this reach,similar
habitats are expected to exist in this portion of
the river under the proposed fi 11 i ng schedul e.
Reduct ions in 1ong-tenn,average monthly stream-
flows of 12 percent (from 60,500 to 53,100 cfs)are
predicted at Susitna Station during May (Table
E.3.30).Even if some of the habitat presently
utilized is dewatered,habitat available along the
margins of the floodplain under the filling flows
will provide replacement habitat.
Wi nter streamfl ow reduct ions a re not expected to
affect habitat utilization in the mainstem below
Taol keetna.Low wi nter flows can stress overwi nter-
i ng fi sh and embryos and are often a 1imit ing fac-
tor for fish populations in Alaska.In the Susitna
River,flow generally reaches its lowest level in
March.Flow reductions are not projected duri ng
this period (Tables E.3.29 and E.3.30).Therefore,
overwintering success of fish or developing embryos
in mainstem habitats is not expected to differ from
existing conditions.
Spring breakup flows will be decreased during fill-
ing.Average monthly flows in May and June will be
reduced by 26 percent at Sunshine Station and by 12
percent at Susitna Station.This reduction is not
anticipated to adversely affect outmigrating salmon
smo1ts in mainstem habitats;neither is it expected
to affect the spawning migration of rainbow trout
or grayling as they move to the tributaries.
-Side-Channel Habitats
Many of the effects identified for the mainstem
under the proposed filling schedule would also
pertain to side-channel habitats.Mainstem flow
generally control s the characteristics of side-
channel habitats;however,changes in stream dis-
charge can result in greater effects on side-
.channel·habitats 'than on mai nstem habitats.As in
mainstem areas,water temperature and turbidity are
expected to be similar to existing conditions below
Talkeetna.
During the open-water season,side-channel habitats
are used for passage by adult and juvenile salmon
and resident fish;for spawning by chum salmon;and
for summer feeding areas by longnose sucker,burbot
E-3-103
2.3 -Anti~ipated Impacts to Aquatic Habitat
and whitefish.Only limited rearing of juvenile
salmon has been observed in this habitat type dur-
ing the open-water season.
Reductions in streamflow during August may dewater
some salmon-spawning habitat in side channels.Six
side-channel spawning areas were identified below
Talkeetna in 1981;none were found in 1982 (Table
E.3.13).Salmon spawning activity in this habitat
type is generally located in side channels with
relatively high streambed elevations at their up-
stream end.These areas are protected from the
high scouring flows and are able to retain sub-
strates suitably sized for spawning.The high
streambed elevation also makes them susceptible to
dewatering under reduced mainstem discharge.The
lower streamflows proposed during August may reduce
the availability of spawning habitat in these
areas.
The proposed filling flow regime may affect rearing
habitat in side channels below Talkeetna.Side
channel s have a gradation of streambed el evations
from high overflow channels to low,nearly contin-
uous flow channels.The effect of reduced stream-
flows on rearing habitat will depend on the stream-
bed elevation of the side channel.Some rearing
habitat for juvenile anadromous and resident fish
will be lost if side channels dewater or water
depths become too shallow.Generally,reduced
flows increase the available rearing area as young
fish prefer low velocities (ADF&G 1982a,Wilson et
ale 1980,and Environaid 1982).If side channels
with suitable streambed elevations exist in this
reach,new rearing areas should become available
where the flow reductions result in decreased velo-
cities but still maintain sufficient depth.Thus,
the potential exists for the location of the rear-
ing habitat to change,but the availability of
reari ng habitat woul d be s imil ar to pre-project
levels.
Rearing habitat and summer feeding areas may be
limited by the availability of food in side-channel
habitats.Su spended sediment load and peak flows
contribute to low benthic production in the Susitna
River.Since little change is expected in these
parameters below Talkeetna (R&M Consultants 1981,
1982c),the change in hydraulic characteristics is
E-3-l04
-
-
-
.....
2.3 -Anticipated Impacts to Aquatic Habitat
not expected to be sufficient to increase utiliza-
t i on of these habitats by anadromous juveni 1e and
resident fish as feeding areas.
-Slough Habitats
Few sloughs below the confluence of the Chulitna
River have been extensively sampl ed.Slough habi-
tats in this reach have been identified as rearing
and possible spawning areas (ADF&G 1981b,1981d,
1981c).Many of these areas are i nfl uenced by
tributary streams and,to a lesser degree,by the
mainstem of the Susitna River.Chum,pink and
sockeye salmon spawn in slough habitats below the
Chul itna confl uence.Juvenil e coho and chi nook
salmon have been found using these areas for rear-
ing and'overwintering (ADF&G 1981d).Rainbow
trout,burbot,longnose sucker,and whitefish U$e
these habitats seasonally (ADF&G 1981e).
Sloughs in the Talkeetna to Cook Inlet reach may be
generally affected in the same way as sloughs above
Talkeetna.The magnitude of predicted change in
mainstem flow is less in this reach;therefore,the
magnitude of changes to slough habitats and the
resultant impacts to fishery resources are expected
to be small ere
-Tributary Habitats
The tri butary habitats in the Tal keetna to Cook
Inl et reach of the Sus i tna Ri ver are not expected
to be significantly affected by the project.The
project would not alter any of the existing physi-
cal processes in the tributaries with the excep-
tion of the area near tributary mouths.The main-
stem creates a backwater at the mouths of the tri-
butaries,which provides habitat for rearing juve-
niles and resident fish (ADF&G 1981de).
The stage in the mai nstem control s the extent of
these backwater areas.Flow reduct ions under the
proposed fill ing schedule may alter the physical
characteristics of the tributary mouths in the
upper portion of this reach.During the open-water
season,mai nstem di scharge wi 11 be reduced by 12 to
34 percent at Sunshine Station (Table E.3.29).
Reductions in flow in June (34 percent)and July
(28 percent)may reduce the areal extent of these
backwaters.
E-3-105
2.3 -Anticipated Impacts to Aquatic Habitat
Tri butari es that enter the mai nstem Susitna Ri ver
in the lower portion of this reach should be mini-
mally affected,since the percent change in dis-
charge will be relatively small.Flow reductions
ranging from 13 to 8 percent are anticipated from
June through August at Susitna Station (Tab1e
E.3.30).Tri butari es are not expected to become
perched because of these reductions in mainstem
discharge.
During the winter,tributary mouths provide impor-
tant overwintering habitat and may provide spawning
habitat for burbot.Because there will be no
reduction in mainstem discharge during the ice
covered season,winter conditions are expected to
remain the same as pre-project conditions.
(iv)Estuary
Since only minor increases in salinity are antici-
pated duri ng reservoi r fi 11 i ng,impacts to fi shery
resources are not expected.
(c)Operation of Watana Dam
Operation of Watana dam will substantially alter the physi-
ca1 environment both upstream and downstream from the dam.
A summary of major downstream impacts,both beneficial and
adverse,is presented in Table E.3.31.
(i)Reservoir Habitats
The Watana reservoi r wi 11 have an area of approx i-
mately 38,000 acres (15,200 ha)with depths up to 735
feet (223 m).The reservoir will experience an
annual drawdown of about 95 feet (28.8 m)from 2185
feet (662 m)above mean sea level to 2090 feet
(633 m).During a dry year,such as occurred in
WYl970,the lowest operational level will be 2075
feet (629 m)occurring at the end of April (Chapter
2.Figure E.2.149).The minimum acceptable level for
operation is 2065 (626 m)feet or a total drawdown of
120 feet (36 m)(Chapter 2.Figure E.2.169).Water
quality conditions expected in the reservoir are
discussed in Chapter 2.Section 4.1.2(e)and are not
expected to preclude fish utilization of the
reservoir.
E-3-106
~,
~-
-
,...
2.3 -Anticipated Impacts to Aquatic Habitat
Habitat potential of the reservoir is considered to
be 1 imited because of low product i vity.The reser-
voir will be oligotrophic because of summer turbidity
levels of 30-40 NTU,(Chapter 2,Section 4.1.3[c])
while the 95-foot (28.8-m)October to May drawdown
will inhibit development of a 1 ittora1 zone.Thus,
food availability may limit fish populations in the
reservoi r.
As discussed under reservoir filling (Section
2.3.1(b),limited populations of grayling burbot,
lake trout,whitefish,and Dolly Varden are expected
to utili ze the reservoi r yea r-round.An ana 1ys is of
spawning habitats in relation to the annual drawdown
cycle was performed to evaluate the potential for
successful reproduction in the reservoir.Filling of
the Watana reservoi r wi 11 usually be i nit i ated in
May,at a minimum pool level of about 2090 feet
(633 m),and continue through August or early
September as the water surface elevation reaches its
maximum 1eve1 (2185 feet [662 m]in wet years)a
95-foot (28.8-m)vertical ga"in (Figure E.3.22).
Annual reservoir filling will progressively inundate
mainstem and tributary habitats.Reservo";r drawdown
will commence in October and continue through the end
of April as water levels decline to an average mini-
mum elevation of 2090 feet (633 m)above mean sea
level.Tributary and mainstem habitats of the
Susitna River and shoreline habitats in the reservoir
wi 11 be progressively dewatered duri ng the wi nter
season.
Arctic grayling select spawning sites within 10tic
habitats (Morrow 1980).Embryo incubation conse-
quently occurs within tributary reaches,indicated as
being above the reservoir water surface elevation in
Fiyure E.3.22.Gray1 i ng withi n the Watana reservoi r
will spawn in tributaries upstream from the minimum
reservoir pool in May and June.Rising water surface
levels (Figure E.3.22)will cause sediment deposition
in spawning areas resulting in mortalities to devel-
oping embryos.(This is discussed in Section 2.3.1
[b][i].)Survival of grayling embryos is thus
expected to be low within reaches of tributaries that
are inundated during May and June.Figure E.3.22
indicates that grayling embryos incubating below an
elevation of.2133 feet (646 m)will be inundated
prior to hatching.Embryos spawned above 2133 feet
(646 m),a vertical rise of 30 to 35 feet (9 to
10.6 m)above the water surface elevation at the time
E-3-107
2.3 -Anticipated Impacts to Aquatic Habitat
of spawning,will not be affected.Table E.3.28
shows the length of the major tributaries that will
be inundated during the May to June period.
Lake trout,humpback whitefish,and burbot are expec-
ted to spawn within the reservoir during the fall and
winter with embryos incubating during winter and
spring (Figure E.3.22).In Alaska and British
Col umbi a,1ake trout spawn in September and October
at depths from 3 to 110 feet (0.9 to 33 m);humpback
whitefish spawn in October and November within 20
feet (6 m)of the surface;and burbot spawn in
December within 20 feet (6 m)of the surface (Morrow
1980).
The decrease in water surface elevation during winter
is expected to dewater humpback whitefi sh and burbot
embryos (Fi gure E.3.22).Lake trout embryos depos-
ited above an elevation of 2120 feet (642 m)wi 11 be
dewatered while those spawned below a depth of 65
feet (19.7 m)(elevation 2120 feet [642 m])in
September and October are expected to survive.
Dolly Varden embryos,which are deposited in tribu-
taries during the fall,will not be affected by the
drawdown cycl e.
As presented in Section 2.3.1(b)(i),reservoir habi-
tats w"ill provide overwintering habitat for grayl ing,
lake trout,burbot,whitefish,longnose sucker,and
Dolly Varden.
(i i)Watana Dam to Talkeetna
-Malnstem Habitats
The primary impacts of Watana operation on the
mainstem habitats between Talkeetna and Watana
are,
•Altered seasonal flow regime;
•Altered temperature regime;
•Reduced sediment load downstream of the dam;and
•Altered water quality parameters.
•Open-Water Season
Open water post-project flows in the mai nstem
would be substantially reduced from pre-project
conditions.Predicted reductions in average
E-3-108
,~--,
2.3 -Anticipated Impacts of Aquatic Habitat
monthly flows at Gold Creek range from 22 to 62
percent of pre-project flows over the peri od of
May,through September (Table E.3.32).Secondary
impacts of reduced flow include,
••Decreased flow velocities;
Decreased depths in many mainstem habitats;
••A reduction in the number and magnitude of
flood events in this reach of the Susitna
Ri ver;and
Decreased sediment transport.
Because use of mainstem habitats appears to be
limited in part by high velocities,decreased
streamflow and the corresponding decrease in
velocity may improve the utility of mainstem
habitats for both resident and anadromous fish.
Pri or to construct i on of Devil Canyon dam,chi n-
ook salmon will be able to pass through the can-
yon,which is presently unpassable,and utilize
spawning habitat available in tributaries up-
stream from Devil Canyon and below Watana dam.
Operating flows are higher than filling flows
from May through Jul y and are thus expected to
provide greater depths than fill ing flows (Sec-
tion 2.3.2 (b)[ii]).Depths associated 'with
operat i on flows are generally not expected to
si gnifi cantly decrease wetted perimeter because
of the rectangul ar channel confi gurat i on of
existing mainstem areas.Depths are expected to
be sufficient for fish passage.
The significant reduction in the number and mag-
nitude of flood events in this reach of the
Susitna River can have several beneficial effects
on mainstem habitats.Presently,the Susitna
River at Gold Creek carries peak flows of 75,000
to 80,000 cfs (la-year frequency).These flows
transport 1 arge amounts of sediment,scour the
riverbed,and remove most of the suitable spawn-
ing gravels.Reduction of these peak flows would
reduce these habitat disruptions.In addition,
recent studies of high streamflows of 38,500 cfs
in August 1981 (ADF&G 1981b and 1982a)indicate
that flows of this magnitude inhibit upstream
mi grat ion of adult sal mono Mi grati on resumed
when the flows receded.Operation of the project
E-3-109
2.3 -Anticipated Impacts to Aquatic Habitat
will decrease the magnitude and frequency of high
flows and associated velocities,thus reducing
disruptions in migrations.
During operation of Watana dam,approximately 80
percent of the sediment load upstream of Watana
will settle out in the reservoir and be trapped
behi nd the dam.Sediments 1ess than 3 to 4-
micron in diameter (20 percent of the sediment
load)will pass through the dam and be trans-
ported downstream to Cook Inlet.
Decreased sediment load combined with post-
project flow reductions will result in decreased
open-water turbidity downstream of Watana.The
relatively clear water will scour silts and sand
from the substrate downstream from the dam and
transport them down river.Over time,this will
resul tin the removal of fi ne sediments from the
streambed.However,much of the riverbed above
Talkeetna is presently armored with large gravels
and cobbl es and si 1ts probabl y wi 11 be removed
only from the surface of the streambed.De-
creased sediment load is also expected to improve
benthic production,since siltation of intersti-
tial spaces will be reduced and light penetration
will increase.At present,high flows may limit
benthi c production in the mai nstem as frequent
bed movement may preclude the develop.nent of a
stable environment.
The combination of impacts discussed above are
expected to produce the following changes to
spawni ng and rearing habitats duri ng the open-
water season of Watana operation.
Small,isolated spawning areas located on the
river margins behind velocity barriers may be
degraded or dewatered.The creat i on of new
spawni ng habitat be natural process appears
unlikely.Although adequate depth and veloci-
ties are likely to exist,the lack of suitable
substrate would probably limit spawning in
this type of habitat.The streambed of most
of the mai nstem channel is composed of 1 arge
cobbles and boulders (R&M Consultants 1981c).
Even though flood flows would no longer flush
gravels from this reach,the recruitment of
gravel to the river will be limited because of
E-3-11 0
PC::"-',
I'
i
2.3 -Anticipated Impacts to Aquatic Habitat
sediment trapping in the reservoir.Isolated
deposits of gravel will occur downstream from
tributary mouths and may provide some suitable
spawning habitat.
Rearing habitat in the mainstem is expected to
increase under post-project conditions.
Reduced velocities and turbidity will probably
benefit young fish and resident adults.Areas
providing suitable habitat will likely still
be 1 imi ted to ri ver margi ns or other 1ow-
velocity areas created by obstructi ons in the
channel.Increased benthic production would
also enhance rearing habitats by providing
increased avai 1abi 1ity of prey items.Some
fish presently use the turbidity as cover,
thus increased clarity may result in greater
predation on small fish.With increased water
clarity,additional sport fishing may be
imposed on the fi sh in thi s reach of the
River •
•Winter/Ice Season
During the winter (October through April),main-
stem habitats are used by rearing salmon and
resident fish,including rainbow trout,burbot,
whitefish,and longnose sucker.Fish move out of
the tributaries to mainstem habitats where most
overwintering occurs (ADF&G 1981d,1981e).The
impacts of Watana operation on these mainstem
habitats include,
Increased water temperature leading to a
change in ice cover;
Increased winter flows varying from 38 percent
in October to 650 percent in February;and
Increased turbidity.
Winter thermal characteristics of the reservoir
determine the outflow temperatures and directly
influence downstream water temperatures.The
outflow from the Watana reservoi r will 1 ikely be
about 4°C (39.2°F)at the beginning of winter,
cool quickly and remain about 1°(33.8°F)to 2°C
(35.6°F)throughout the remainder of the winter
(Chapter 2,Section 4.1.3[c][iJ).Temperatures
E-3-l11 .
2.3 -Anti ci pated Impacts to Aquati c Habitat
such as these would preclude development of an
ice cover in the upper secti on of thi s reach,
thus eliminating the associated staging and
backwater effect.Ice front progressi on above
the confluence is expected to start in late
December or early January with the upstream edge
of the ice cover progressi ng to between Sherman
(RM 130)and Portage Creek (RM 149)(Chapter 2,
Section 4.1.3(c)[ii]).Assuming reservoir
out flow temperatures decrease 1i near ly from 4°C
(39.2°F)on October 15 to 1°C (33.8°F)on January
1,an ice cover wi 11 form at RM 149.If the
outflow temperatures are constant at 4°C
(39.2°F),an ice cover wi 11 form by RM 130
(Chapter 2,Section 4.1.3(cHii]).Downstream
from the upper end of the ice cover,winter water
temperatures are expected to differ little from
pre-project conditions.
Because backwater and stagi ng effects wi 11 be
eliminated in the post-project,open-water reach,
the river in this reach is expected to have
higher velocities,less depth and less wetted
perimeter than under pre-project condition with
an ice cover (Section 2.3.1(cHii]).In those
areas that ret ai n an ice cover,wetted peri meter
and depth wi 11 greatly increase in many mainstem
h abi tat s because of st agi ng and increased di s-
charge,although high velocities in several steep
gradient sections may prevent the formation of an
ice cover in these areas.St agi ng wi 11 occur at
the ice front,and if the stage of the river is
raised sufficiently,mainstem waters will flood
side-channels and sloughs.
Turbidity is projected to increase slightly over
present winter conditions.Particles less than 3
to 4 microns will remain in suspension in the
reservoir,increasing downstream turbidity levels
(Chapter 2,Section 4.1.3(cHiv]).This slight
increase in turbi di ty is not expected to adverse-
ly affect fish populations using mainstem habi-
t at s.Fi sh apparent ly successfully overwi nter in
habitats with similar levels of turbidity in the
Kenai Ri ver,Al aska (Burger et al.1982).In-
creased post-project wi nter flows,warmer water
temperatures,and altered ice processes may have
the followi ng impacts on fi sh in the Talkeetna to
Watana reach.
E-3-1l2
"""
.....
r
2.3 -Anticipated Impacts to Aquatic Habitat
Increased flows will provide more under-ice
overwintering habitat for juvenile anadromous
and resident fish by increasing depth and
wetted perimeter •
••Warmer water temperatures are expected to
benefit overwintering fish by reducing mor-
talities associated with freezing.Stream
temperatu re and di scharge wi 11 remai n fai rly
stable,preventing fish from becoming trapped
in unfavorable areas that freeze.During the
winter of 1981-1982,information on fish dis-
tribution suggested that fish were seeking
warmer water temperatures.Bustard and Narver
(1975)reported that juvenile coho move to
warmer water for overwi nteri ng when warmer
water is available.
If the increased surface water temperatures
cau se an increase in i ntergravel water tem-
peratures (i.e.,the intergravel temperature
is not controlled by upwell ing ground water),
then incubating embryos will be affected.
Incubation rates of fish embryos and benthic
invertebrates are closely tied to water tem-
peratu res.An increase in i ntergravel water
temperatures would likely accelerate develop-
ment and resu 1t in early emergence.Early
emergence has been related to decreased sur-
vival rates in both benthic invertebrtates and
Pacific salmon (Bailey et ale 1974).Pink
salmon would be especially vulnerable to mor-
tality related to early emergence,since they
tend to sel ect areas directly influenced by
surface water and tend to out-migrate shortly
after emergence.Young fish may begin to
out-mi grate before downstream conditi ons are
suitable.Temperatures below the confluence
of the Chul itna Ri ver are 1i kely to be near
O°C (32°F).Cllt-migrants encountering these
temperatures may experience thermal shock,
which has been linked to increased mortality
(Brett and Alderdice 1958 and Brett 1952).
Chum salmon would be less susceptible to
changes in surface water temperatures as the
adu 1ts tend to select areas i nfl u enced by u p-
well ing ground water,which is buffered from
changes in mainstem surface water.In addi-
tion,chum salmon may rear for approximately a
E-3-ll3
2.3 -Anticipated Impacts to Aquatic Habitat
month before movi ng downstream.Early emer-
gency should have little effect on coho sal-
mon,since they remain in freshwater habitats
for two years and have been found to seek out
wanner areas in the spring.U.S.Fi sh and
Wildlife is currently studying the effects of
projected water temperature changes on incuba-
tion of Susitna River sockeye and chum salmon
eggs.The four temperature regimes under
study were chosen to provide an analysis of
probab le post-project temperatu re vari at ions
on incubation times as compared to pre-project
mainstem and slough water temperatures.
Other than the turbidity and temperature changes
discussed above,no impacts to water quality
parameters are anticipated under winter or open-
water conditions under Watana operation.Gas
supersaturation,which is caused by water passing
over a high spillway into a deep plunge pool and
dissolving air into the water,will not be a pro-
blem at Watana.Mitigation through the use of
cone valves in the spillway design is discussed
in Section 2.4.4(d).
-Side-Channel Habitats
Many of the project-i nduced physical changes iden-
tified for mainstem habitats would also occur in
side-channel habitats.Reductions from pre-project
streamflow during the open-water season may dewater
some spawning habitat presently used by salmon.
The lower operational flows during the spawning
season may concentrate spawning salmon in areas
that are less likely to dewater under the higher
wi nter flows'and thus increase spawn i ng success.
Side channels with lower streambed elevations are
presently subject to scouring at high flows and
many do not have substrates suitable for spawning.
Most are armored with 1arge cobbl es and boul ders
that are underlain with large gravels embedded in
silt and sand.
Operational flow should result in additional rear-
ing areas becoming available in side-channel habi-
tats duri ng the open-water season.Lower di s-
charges generally result in decreased velocities
and depths.This would likely improve the quality
of these areas as rearing habitat for some resident
and juvenile anadromous fish.
E-3-114
2.3 -Anticipated Impacts to Aquatic Habitat
Post-project water temperatures in the side-channel
areas will be similar to mainstem water tempera-
tures,since mainstem water is the controlling
factor.However,temperatures of water in 1ateral
margins of the side channels may be slightly warmer
than mai nstem water because of shallower depths,
slower velocities,and increased water clarity.
Increased water temperatures may enhance the
qual ity of reari ng habitat in the side-channel s
(Abbad 1980;Clarke et al.1981).
The approximate tenfold decrease in turbidity dur-
ing the open water season will likely have a bene-
ficial effect effect on food production in side-
channel habitats.More energy woul d be avail able
for primary production,thus increasing the food
base for other trophic levels.The post-project
flow will be carryin9 a lower sediment load and may
also remove many of the silts and sands presently
occupying the interstitial spaces of the substrate.
This is expected to provide more habitat for ben-
thic invertebrates.
During the late fall and winter period,mainstem
discharges at Gold Creek will increase approxi-
mately 40 to 655 percent over pre-project flows
(Tabl e E.3.32).The magnitude of the increase in
flow expected to occur in side-channel habitats is
dependent on the stage in the mai nstem and the
streambed elevation of the upper end of the side-
channels.Presently,the stages in the side-
channel s drop in the fall as mai nstem flows
decrease.As the river forms an ice cover,the
side-channel stages increase because of the back-
water effects caused by ice formation.Duri ng
operation of Watana dam,the flow at Gold Creek
will not drop significantly below 7700 cfs in the
fall or winter period.Wetted perimeter,depth,
and velocities are expected to increase in side-
channels during the winter months.Side channels
will be less susceptible to dewatering and freezing
under the higher post-project winter flows than at
present.
Incubation success in side-channel areas may
imp rove under post-proj ect conditions as the eggs
will be less 1 ikely to dewater.Increased flows
are expected to also provide greater i ntergravel
flow,which would benefit incubating embryos and
alevins.The increased post-project winter flows
E-3-115
2.3 -Anticipated Impacts to Aquatic Habitat
would also increase the availability of over-
wintering habitat for juvenile anadromous and
resident fish in side-channel habitats by pro-
viding more living space and being less likely to
freeze during the winter.
-51 au gh Habitats
During the open-water season,impacts to slough
habitats above Talkeetna under operation of
Watana dam are not expected to substantially dif-
fer from those resulting from filling the Watana
reservoir.5treamf10ws during late fall,winter,
and early spring will be increased,providing a
higher stage in the mainstem.The increased
stage is expected to increase the rate and areal
extent of ground water upwelling in the sloughs
and the potential for overtopping the upstream
end of the slough causing flow through the slough
and flooding.Incubation success of salmon
embryos may be improved because of the increased
g rou nd water flow.
Post-project winter conditions may affect incuba-
tion and overwintering in the sloughs.The in-
creased flows in conjunction with increased water
temperatures will change the ice processes in
this reach of river.Presently,as the mainstem
forms an ice cover,the stage increases because
of backwater effects.These staging effects were
measu red near Go1 d Creek between RM 135 and RM
138 on December 12,1980 (R&M Consultants 1982d).
The mainstem discharge was 1800 cfs.At 11:30
a.m.,the stage at the leading edge of ice
corresponded to a discharge of 19,000-29,000 cfs.
By 2:00 p.m.,the ice edge had advanced upstream
about 2300 feet (690 m);the under-ice stage 5900
feet (1787 m)downstream from the edge was
representative of a flow of 23,400 cfs.Under
post-project conditions,the river is expected to
form an ice cover up to RM 130 and,depending on
metero1ogica1 conditions,the ice cover may
extend up to RM 149.Thu s,the stage in the
river and the wetted perimeter of sloughs and
side channels would probably decrease relative to
pre-project winter conditions upstream from the
ice front.If the decrease in wetted perimeter
and water depth results in dewatering or
increased depth of freeze,eggs incubating in the
gravels could be adversely affected.Overwinter-
i ng areas may a1 so be adversely affected by the
E-3-116
~,
(:---~
-
,-.
I
I
2.3 -Anticipated Impacts to Aquatic Habitat
same physical processes causing increased
mortalities for juvenile anadromous and resident
fish.
In sloughs at and downstream from the ice cover
front,the post-project mainstem flow could overtop
the head ends of the sloughs.The addition of near-
freezing mainstem water would reduce the surface
water temperatures of the sloughs and increase the
formation of ice.In some cases,considerable
icing could occur;and the value of these areas for
overwintering would be reduced.
The ice would reduce surface water temperatures in
the sloughs well into the spring.Since the mech~
ani cal "breakup 1 ikely would not occur,these ice
formations in the sloughs would melt out rather
than being carried out by high flows.Ice may be
present in the sloughs until late June.The
presence of ice would reduce the surface water tem-
peratures and may alter the quality of these areas
as early nursery areas for emerging fry.
-Tributary Habitats
Tributary habitats in the Watana d~m to Talkeetna
reach would be affected similarly under both fil-
ling and operation during the open-water season.
Augmented wi nter flows wi 11 increase the amou nt of
overwintering habitat associated with tributary
mouths,since higher discharge in the mainstem will
increase the water depth and extent of backwaters
at the tributary mouths.Studies indicate that
tributary mouths are important overwi nteri ng habi-
tat (ADF&G 1981d,1981e).
....
(i i i)Talkeetna to Cook Inlet
Project effects in this reach of river are expected
to be considerably reduced in magnitude from those
presented for the Watana dam to Talkeetna reach
because of the influence of the Chul itna and
Talkeetna Rivers.Many of the changes identified
under the fill ing schedule (Section 2.3)for the
a pen-water season wi 11 be the same under a perat i on
flows.Winter flows will be increased.
E-3-117
2.3 -Anticipated Impacts to Aquatic Habitat
-Mainstem Habitats
During the open-water season,mainstem habitats
will be similarly affected during f"illing of the
Watana reservoir and operation of Watana dam.
Operational flows during this period are slightly
greater than filling flows in the late spring and
early fall and nearly equal to filling flows duriny
summer months (Tables E.3.29, E.3.30,E.3.33,and
E.3.34)•
Bering cisco spawned in mainstem habitats during
October 1981 and 1982.Si nce 1 ittle change in
average monthly streamflow or in stream temperature
is anticipated during October,these fish are not
expected to be adversely affected by the project.
In the Susitna River,eulachon spawn mainly below
the Yentna River in mainstem habitats.Eulachon
spawning areas identified during spawning surveys
in May 1982 were located in relatively shallow
water adjacent to cut banks and in riffle cones or
bars with moderate velocities (ADF&G 1983).These
habitats would probably exist to the same extent in
this portion of the river under post-project condi-
tions as during pre-project conditions.This seg-
ment woul d be subjected to the 1 east amount of
change,since it is buffered by inflow from all
major tributaries below Talkeetna.Reductions in
average monthly streamflow of 10 to 26 percent at
Sunshine (pre-project flows of 27,700-64,500 cfs to
operational flows of 24,900-48,300 cfs)and 5 to 13
percent at Susitna (pre-project flows of 60,800-
132,400 cfs to operational flows of 57,900-117,400
cfs)are predicted from May through September
(Tables E.3.33 and E.3.34).
During the winter (October through April),in-
creases in average monthly discharges of 17 to 277
percent at Sunshi ne (pre-project flows of 2600-
13,800 cfs to operational flows of 9500-16,100 cfs)
and 18 to 114 percent at Susitna (pre-project fows
of 6300-30,400 cfs to operational flows of 13,300-
32,700 cfs)are predicted (Tables E.3.33 and
E.3.34).Water temperatures are not expected to
differ from pre-project conditions.Increases in
discharge will result in increases in wetter peri-
meter.
E-3-118
-
2.3 -Anticipated Impacts to Aquatic Habitat
The availabil ity of overwinter-ing habitat is
expected to increase becau se of increased water
depth and wetter perimeter.Si nce the flow wi 11
remain fairly constant,increased fish and embryo
survival may result from reduction of mortal ity
associated with freezing.
-Side-Channel Habitats
As discussed under the reservoir filling flow
regime,reductions in streamflow during the open-
water season may dewater or degrade some spawning
habitat presently used by salmon,as well as affect
reari ng and summer feedi ng habitat for resi dents
and anadromous juveniles.
Du ri ng the wi nter peri od,st reamfl ows ins i de-
channel habitats wi 11 be increased because of the
increased winter discharge (Tables E.3.33 and
E.3.34).These increased winter discharges are
expected to have a beneficial effect on overwinter-
ing fish and incubating embryos.Increased dis-
charge will increase depths in side-channel areas.
This will provide more living space and should pre-
vent dessication and freezing in these areas.
Increased surface flow may also result in increased
intergravel flow,which would benefit embryo devel-
o pnentand overwintering ju venil es.
-Slough Habitats
Increases in wi nter st reamfl ows a re expected to
have a benefi ci al effect on slough habitats.The
augmented discharge will increase the areal extent
of the backwater at the slough mouth,creating
greater water depth withi n the slough.The u p-
stream extent of the backwater effect wi 11 depend
on the gradient of the slough.Increased water
depth may prevent a porti on of the slough from
freezing and incr.ease the avail abil ity of over-
wintering habitat.
-Tributary Habitats
Tributary mouths are expected to be affected Slml-
larly under both filling and operation of Watana
dam during the open water season.Ilrring the win-
ter,tributary mouths provide important overwinter-
·ing habitat.The effects of higher discharge ;in
2.3 -Anticipated Impacts to Aquatic Habitat
the mainstem should increase the areal extent of
the backwaters and increase the amount of
overwintering habitat associated with tributary
mouths.
(ii)Estuary Habitats
Si nce only mi nor changes in sal i nity are predicted
under project operation (Chapter 2,Section 4.1.3
[fJ[iiiJ),no impacts to fish resources in the
estuary are anticipated.
(d)Summary of Impacts Associated with Watana Dam
(i)Construction Impacts
The primary long-term aquatic impact related to con-
struction of Watana dam will be the increase in har-
vest pressure result i ng from the inc reased access
afforded by the project roads.In the absence of
stricter harvest regulations,the increase in access
near the impoundments will cause substantial altera-
tions in resident fish population structure,with the
present population of large,long-lived grayling
being replaced by younger individuals.
There will be degradation of aquatic habitat at
stream crossings but with proper construction prac-
tices as discussed in Section 2.4.3,this impact is
not expected to noticeably affect fish populations.
Construction activities and reservoir clearing acti-
vities will cause temporary increases in siltation
and turbidity in some of the project area clear-water
streams.These impacts are not expected to extend
beyond the constructi on peri ode Simi 1arly,a ltera-
tions in water quality and disturbance to fish popu-
lations are expected to impact fish only during the
construction period.There will be a continuous
possibility of fuel spills during the construction
peri od when numerous constructi on vehi cl es a re pre-
sent in the project area.The possibility of acute
spills will be reduced under operation,but chronic
spills will occur for the life of the project.Acute
spills could cause locally significant impacts to
fish populations,while chronic spills will cause
gradual habitat degradation,particularly along
roadways.
E-3-120
2.3 -Anticipated Impacts on Aquatic Habitat
The borrow site at the mouth of Tsusena Creek will
create aquatic habitat at the expense of riparian
habitat.Th i snew aquatic habitat is expected to
provide productive feeding and overwintering habitat
for fish.
(ii)Filling Impacts
Impacts associated with the three years needed to
fill the Watana reservoir are divided into impound-
ment impacts and downstream impacts.
The primary long-term impact associated with the fil-
ling of the Watana reservoir is the loss of clear
water tributary habitat.The tri butary habitat that
wi 11 be inundated currently supports a substant i al
population of grayling,estimated to be at least
15,100 in 1982 (Table E.3.17).Aquatic habitats
withi n the reservoi r are not expected to support a
significant grayling population (Section
2.3.1{b)[iJ).
Between Watana dam and Talkeetna,the primary impacts
associated with filling will be a reduction in spring
and summer flows,reduction in sediments,and altered
temperature regime,particularly during the second
year of filling.Mainstem and side-channel habitats
will contain less turbid water and be-subjected to
less extreme fluctuation in water levels and flow
duri I1g the summer.These changes are expected to
provide more favorable fi sh habitat than now exists
in these areas.During the second year of filling,
4°C (39.2°F)water will be released at the dam;this
is expected to warm to 5°to 6°C (41°to 42.8°F)at
Talkeetna.The adult salmon migration into the
Watana dam to Talkeetna reach may be delayed,and
some of the returning adults,particularly pink and
coho salmon,may select alternative spawning areas
because of the lower summer temperatures.This
impact is expected to be confined to the second year
of filling and have no long-term impacts on popula-
tion levels.The decreased temperature is expected
to decrease the growth of resident and juvenile
anadromous fish for the one summer,but significant
impacts to the popul at ions are not expected (see
Section 2.3.1{b)[iiJ).
Slough habitats between Watana dam and Talkeetna are
expected to be the habitat type most significantly by
filling flows.In the absence of mitigation fea-
tures,filling flows are expected to cause access
E-3-121
2.3 -Anticipated Impacts to Aquatic Habitat
problems for returning adult chum and sockeye salmon.
For salmon that do gain access,the spawning area
within the sloughs may be reduced in area because of
the lower mainstem flows (see Section 2.3.1(b)[ii]).
If un-mitigated,these impacts would reduce the
number of spawning chum and sockeye salmon in the
sloughs above Talkeetna.Under a worst case scenario
in which all slough spawning is lost,the total run
to the Susitna River would be reduced by an estimated
11,840 chum;9200 sockeye,and 3550 pink salmon based
on 1981 and 1982 escapement data (see Section
2.3.2(b)[ii]Slough Habitat).The sockeye spawning
in sloughs upstream fram Talkeetna are considered to
be strays from Chu1 itna and Tal keetna stocks (ADF&G
1983),thus there may be no product i on from these
adults.If this is true,there would be no loss of
sockeye to the fishery.
Tributary habitats below Watana dam and all habitats
below Talkeetna are not expected to be significantly
impacted duri ng the fi 11 i ng of the Watana reservoi r
(Section 2.3.1(b)[ii]and [iii]).
(iii)Operation Impacts
Operation impacts,as with filling,are divided into
impacts due to the impoundment and downstream
impacts.
The habitat withi n the reservoi r is not expected to
support substantial fish populations (Section 2.3.1
(c)[i]).The annual drawdown cycle will limit spawn-
i ng habitat of g ray1 i ng,1ake trout,burbot,whi te
fish and 10ngnose sucker.Littoral rearing habitat
is also not expected to be productive because of the
drawdown cycle and summer turbidity levels.Grayling
are expected to reside at the mouths of the tribu-
taries.Lake trout and Dolly Varden are expected to
develop reproducing populations within the reservoir.
Other species are expected to migrate into the reser-
voir from upstream habitats,primarily to overwinter,
and may residua1ize.
Between Watana dam and Talkeetna,the primary opera-
tional impacts will be similar to those discussed for
filling:decreased summer flows,decreased flow vari-
abil ity and decreased sediment load.During winter,
however,flows will increase over pre-project condi-
tions and will be accompanied by increased tempera-
ture and turbidity.
E-3-122
""'"
.....
.....
2.3 -Anticipated Impacts to Aquatic Habitat
More stable summer flows and decreased turbidity are
expected to improve reari ng habitat in mai nstem and
side-channel habitats.Eventually,mainstem and
side-channel spawning habitats are expected to become
available,as the less turbid water removes intersti-
t i al silt from the presently cemented substrate
(Section 2.3.1(c)[ii]).
The decreased summer flows,however,will likely
cause passage problems for adult salmon entering
slough spawning habitats,as was discussed under
filling impacts.Similarly,spawning habitat within
the sloughs will likely be reduced,since the area of
ground water upwell i ng may be reduced with lower
mainstem flows (Section 2.3.1(c)[ii]).If unmitiga-
ted,these impacts will reduce the number of chum and
sockeye sal mon spawni ng in the sloughs upstream from
Talkeetna.The worst case scenario would be total
loss of slough spawning habitat in this reach,with a
reduction in the total run size,as discussed in the
previous section (Section 2.3.1{d)[ii]).
The increase in winter flow is expected to increase
overwi nteri ng habitat and wi 11 benefit resi dent and
rearing anadromous species.The reduction of flow
variability,peak flows,turbidity,and sediment load
in the mainstem during summer combi ned with increased
winter flow,may lead to increases in the populations
of some resident species,such as rainbow trout and
Dolly Varben,and rearing anadromous species,such as
chinook and coho salmon.The amount of increase,if
any,will depend on the extent to which these physi-
cal factors presently limit the populations.
The increased winter temperatures may increase embryo
development in mainstem and side-channel spawning
habitats and lead to early emergence of alevins.
These early emerging fry are expected to experience
increased mortality if they move downstream and
encounter O°C (32°F)'water below Talkeetna.This
impact will likely affect relatively few fish,pri-
marily pink salmon,since only a small portion of the
salmon spawning upstream from Talkeetna utilize main-
stem and side-channel spawni ng habitats.Other sal-
mon species usi ng these habitats exhi bit behavi or
patterns that reduce thei r vul nerabil ity to these
impacts (Section 2.3.1(c)[ii]).Impacts are not
expected in tributary habitats upstream from
Ta"1 keetna.
E-3-123
2.3 -Anticipated Impacts to Aquatic Habitat
Downstream from Talkeetna the main impact will be an
increase in overwintering habitat in the mainstem and
side channels because of the increased winter flows
(Section 2.3.1(c)[iii]).No significant adverse
impacts are expected.
2.3.2 -Anticipated Impacts to Aquatic Habitat
Associated with Devil Canyon Dam
Impacts sustained by aquatic habitats as a result of construction
and operation of Devil Canyon dam will be similar to those occur-
ring under construction and operation of Watana dam.This sec-
tion addresses additional impacts and increased magnitude of
impacts to aquatic habitats attributable to the development of
Devil Canyon dam,assuming Watana dam is in place.
(a)Construction of Devil Canyon Dam and Related Facilities
(i)Devil Canyon Dam
Devil Canyon dam will be located at RM 152 of the
Susitna River,approximately 32 miles (53 km)down-
stream from the Watana damsite.A concrete arch thin
dam will be built at the downstream end of Devil
Canyon and an earth/rockfi 11 saddl e dam wi 11 be con-
structed at the south end of the arch dam to provide
closure of a low area at the south abutment.The
reservoir behind Devil Canyon will cover 7800 acres
(3120 hal and will be about 32 miles (53 km)long and
not more than 0.5 mile (0.8 km)wide (Figure
E.3.23).
The concrete dam and fou ndat i on wi 11 be 646 feet
(195 m)hi gh and wi 11 have a crest 1ength of 1650
feet (500 m):!An estimated 2.7 mill ion cubic yards
(2,052,000 m )of concrete will be needed to con-
struct the arch dam.The saddl e dam wi 11 be 950 feet
(287 m)across and 245 feet (74 m)hi gh and wi 11
require about 1.2 million cubic yards (912,000 m)
of materi a1.
As with Watana,Devil Canyon dam will have an under-
ground powerhouse,intake structure,outlet works,
main and emergency spillway.A 39-foot (11.8-m)
diameter tailrace tunnel will convey the turbine
discharge approximately 1.3 miles (2.2 km)downstream
from the arch dam.
E-3-124
r:·-.-'"
I~
2.3 -Anticipated Impacts to Aquatic Habitat
During construction of the dam,the river will be
blocked above and below the construction site by
cofferdams.The flow will be diverted into a
30-foot (9-m)diameter horseshoe tu n_nel,1490 feet
(451 m)long,and discharged back into the river
channel.The upstream and downstream cofferdams will
be about 400 feet (120 m)long and 200 to 400 feet
(60 to 120 m)wide.
The adverse impacts upon aquatic habitat at the Devil
Canyon damsite are expected to be similar to those at
the Watana site but of lesser magnitude.
At the Devil Canyon damsite,the Susitna River is
confi ned to a canyon approximately 600 feet (180 m)
deep and 200 to 400 feet (60 to 120 m)wide at river
1evel •The ri ver bottom is primarily composed of
cobbles,boulders,and blocks of rock;the water is.
extremely''turbulent.It is expected that few fish
live in the area of the damsite (ADF&G 1981e).Some
chinook salmon migrated upstream from the Devil
Canyon damsite du ri ng the low summer flows of 1982
(ADF&G 1982e)and are expected to pass through the
canyon during the low spring flows associated with
operation of.Watana dam.
-Alteration of Waterbodies
Impacts from Devil Canyon Dam construction will be
primarily restricted to the vicinity of the dam-
site.A 1I00-foot (333-m)section of the Susitna
Ri ver between the cofferdams wi 11 be dewatered for
7 years du ri ng construction.Al though a small pop-
ulation of Dolly Varden'and at least one sculpin
species as well as possibly other resident species
inhabit that stretch of river,it is not expected
that dewatering will have more than a minor impact
upon availability of suitable aquatic habitat.The
dam fou ndati on wi 11 cover about 90 feet (27 m)of
river bottom.This is considered to be a minor
impact.
Construction of the arch dam and the saddl edam
will require excavation in the river channel at the
damsite.Excavation by blasting or by mechanical
means may result in the introduction of materials
into the Susitna River that would be carried down-
stream.The turbulence of the water at the site
E-3-125
2.3 -Anticipated Impacts to Aquatic Habitat
would preclude sedimentation in that stretch of
river.Adverse impacts from introduction of
increased sediment are expected to be minor.
The greatest impacts during construction of the dam
are likely to be associated with gravel mining and
processing in Borrow Site G.Gravel for filter
material and for concrete aggregate will be removed
from the Susitna Ri ver and from Cheechako Creek
alluvial areas upstream from the damsite (Borrow
Site G).The effects of gravel mining on aquatic
systems have been discussed under Section 2.3.1(a).
Since the material removal sites will be inundated,
impacts at the sites will be transitory.
Changes in Water Quality
Potential impacts to water qual ity woul d primarily
be caused by increases of turbidity due to erosion
and through discharge of effluent from the concrete
batching process.To minimize water quality im-
pacts,all process waters wi 11 be treated before
being discharged to the Susitna River.Turbidity
increases in the Susitna River are expected to be
neglible.See Section 2.3.1(a)for discussion.
-Disturbance of Fish Populations
Instream activities during material extraction near
Cheechako Creek could disrupt fish movements,
spawning,and rearing in the creek,depending upon
location,type and duration of activities.It is
unlikely that the damsite itself is located in a
stretch of the Susitna regularly inhabited by fish;
therefore,it is expected that the excavati on and
blasting required at the damsite would not be dis-
ruptive to fish populations.
(ii)Construction and Operation of
Devil Canyon Camp and Village
During construction of Devil Canyon dam,housing will
be constructed for 1900 persons (Chapter 3,Section
3.3.1[dJ).The construction camp and construction
village will be located between 1.7 and 3.4 miles
(2.8 and 5.6 km)southwest of the damsite.The camp
will include bachelor dormitories,cafeteria,ware-
houses,offices,hospital,and recreational build-
ings.The village will contain housing for 170 fami-
1 i es and wi 11 inc 1ude a school,stores,and a recrea-
t i on area.
E-3-126
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""'"I
2.3 -Anticipated Impacts to Aquatic Habitat
The camp will be approximately 0.5 mile (0.8 km)from
the village.Both developments will be more than 700
feet (210 m)above the Su sitna Ri ver and more than
4000 feet (1200 m)from the edge of the canyon.
Water,sewage,and solid waste disposal facilities
wi 11 be shared by both developments.Water wi 11 be
withdrawn from the Susitna River and effluent from a
secondary treatment system discharged into the river
below the water intake.The upper reaches of Jack
Long Creek border the camp and the vill age to the
south,coming to within 200 feet (60 m)of the camp.
A small unnamed creek drains a series of lakes 3000
feet (900 m)to the east of the camp and enters the
Susitna at RM 150.The creek is paralleled by the
sewage outfall 1ine for 1000 feet (300 m)or about 20
percent of its 1ength..
Both the camps and the village are temporary develop-
ments to be removed when Devi 1 Ca nyon construct i on is
completed.Permanent personnel responsible for
operations of the Devil Canyon dam will 1 ive at the
Watana permanent town.No ai rstri p wi 11 be bu i It;
air access wi 11 be vi a the permanent ru nway at
Watana.
The unnamed creek and 1akes may su pport grayl i ng.
Jack Long Creek contai ns pi nk,chi nook,chum,and
coho salmon (Figure E.3.17).Portage Creek contains
chum,pink,chinook,and coho salmon,rainbow trout,
round whitefish,and humpback whitefish.Chinook
salmon,grayl ing,and Dolly Varden are found in the
1ower reaches of Cheechako Creek.Temporary impacts
resulting from camp/village operations are expected
to be limited to the area within a few miles of the
damsite.
-Alteration of Waterbodies
No water bodies are expected to be alterated as a
result of Devil Canyon camp construction other than
those resulting from gravel mining within the
Su sitna Ri ver fl oodpl ai n at Borrow Si te G.Si nce
this site will eventually be inundated,no
permanent effects of gravel mining will occur.
Camp construction is not anticipated to affect Jack
Long Creek or the unnamed stream.
E-3-127
2.3 -Anticipated Impacts to Aquatic Habitat
-Changes in Water Quality
Erosion into the Susitna River from gravel mlnlng
at the mouth of Cheechako Creek is not expected to
result in adverse impacts to fi she Because of its
proximity to the developments,Jack Long Creek may
receive uncontrolled runoff from the camp area.
However,required drainage facilities and retention
ponds should eliminate this impact and increased
sediment 1evel s shou 1d not adversely affect spawn-
ing habitats in Jack Long Creek.
Water for camp use wi 11 be withdrawn from the
Susitna River,and treated effluent and wastewater
will be returned to the river.The treated efflu-
ent will not affect the waste assimilative capacity
of the Susitna and is expected to have no signifi-
cant effect on the aquatic environment (Chapter 2,
Section 3.3.1 Cd]).Storm drainage and oily water
runoff from the construction camp will be collected
and treated as noted above.
The fuel storage area is located on the south side
of the construction camp about 200 feet (60 m)
above Jack Long Creek.Accidental fuel spills
could reach the creek if storage facilities failed.
It is not expected that runoff from the solid waste
disposal site and the construction village will
adversely affect any waterbodies,since both will
be coll ected and treated the same as the ru noff
from the camp area.
-Direct Construction Activity
The camp and village at the Devil Canyon site will
house 1900 workers for several years (Chapter 2,
Section 3.3.1[d]).It is expected that,as a
result,streams and lakes in the vicinity will be
subjected to increased fishing pressure.This area
has not been heavily utilized for sport fishing in
the past.
The waterbodies most likely to be affected include
Cheechako Creek,unnamed creeks and 1akes,Jack
Long Creek,and to a 1esser extent,the Su sitna
Ri ver and Portage Creek.With the exception of
Portage Creek,these waterbodies are within walking
distance of the camp/village and the damsite.
E-3-128
2.3 -Anticipated Impacts to Aquatic Habitat
Portage Creek enters the Su sitna Ri ver from "the
north about 2.5 miles (4.1 km)downstream from the
dam location on the opposite side of the Susitna
River.
P""'-
i
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I
,....
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(b)Filling Devil Canyon Reservoir
The filling of the Devil Canyon reservoir will be done in
two stages.Upon completion of the dam to a height suffi-
cient to allow ponding above the lowlevel outlet facilities,
the water level will be raised to an elevation above 1050
feet (315 m)but not exceeding 1135 feet (343 m).This
filling will be accomplished in approximately 4 weeks.As
soon as the power facilities and main spillway are comple-
ted (approximately one year or more),the reservoir will be
raised to 1455 feet (440 m),the normal operation elevation,
in 5 to 8 weeks.During filling of Devil Canyon,the down-
stream flows at Gold Creek will not drop below the project
operational minimum flows.
(i)Inundation of Upstream Habitats
Filling Devil Canyon reservoir would inundate approx-
imately 32 miles (53 km)of Susitna River mainstem
habitat and 11 mil es (18 km)of tri butary habitats.
These habitats would be converted from lotic to len-
tic systems with accompanying changes in hydraulic
characteristics,substrate,turbidity,temperature,
and nutrient levels (Chapter 2,Section 3.4.2[c]).
These changes are expected to result in a shift in
s peci es compositi on.The area presently su pports
arctic grayling,burbot,longnose sucker,whitefish,.
and Dolly Varden (ADF&G 1981f).Impacts to mainstem
habitats are expected to be similar to those presen-
ted in Section 2.3.1(b)for Watana Reservoir.The
loss of clear-water tributary habitat in Tsusena and
Fog Creeks will eliminate habitat utilized by approx-
imately 1200 grayl i ng longer than 8 inches (20 cm)
(Tabl e E.3.17).Effects on tributari es and associ-
ated fish are also expected to be similar to those
presented for the Watana Reservoir.Most of the tri-
butari es in the Devi 1 Canyon impou ndment area are
c ha racteri zed by stee p s lopes wit h occas i ona 1 ba r-
riers,such as waterfall s.Cheechako,Devil and
Tsusena Creeks,three tributaries entering the Devil
Canyon impoundment,all contain waterfalls.These
falls will not be inundated by the impoundment and
would still function as barriers to fish passage.
E-3-l29
2.3 -Anticipated Impacts to Aquatic Habitat
The four tributaries that are expected to support
c hi nook spawn i ng du ri ng fi 11 i ng and 0 perat i on of the
Watana dam wi 11 be lost as chi nook habitat after
Devil Canyon dam is in place.
(c)Operation of Devil Canyon Dam
Post-project streamflows under the operation of Devil Canyon
dam would be similar to those under the operation of Watana
dam alone.Most of the impacts to the aquatic habitat would
have occurred under the startup and operation of the Watana
dam.
Few additional impacts are expected to result from operation
of Devil Canyon during the open-water season.Changes in
streamflow are presented in Tables E.3.35,E.3.36,and
E.3.37.
(i)Reservoir Habitat
During operation of the Devil Canyon reservoir,the
water surface elevation will remain at 1455 feet
(440 m)above sea level from November through July,
except du ri ng an extreme drou ght.Du ri ng Au gu st,
water will be released to maintain minimum downstream
flows for returning adult salmon.The water surface
elevation will normally decrease to 1405 feet (425 m)
until downstream flow requirements diminish in late
September.The water level will be returned to 1455
feet (440 m)by the end of October (Figure E.2.111).
The stable water level in Devil Canyon for most of
the year will create favorable spawning conditions
for most fish species.Arctic grayling,lake trout,
bu rbot,whitefi sh and longnose sucker spawni ng is
expected to be unaffected.Dolly Varden embryos that
are deposited in the drawdown zone of reservoir tri-
butaries during September and October may experience
a higher mortal ity than those deposited above the
draw-down zone.The impact to Dolly Varden popul a-
tions in the reservoir is expected to be minor.
Productivity in the Devil Canyon reservoir is
expected to be low because of the turbidity levels
(Chapter 2,Section 3.4.2{c){iii)),but should be
greater than the productivity in the Watana reservoir
becau se of the 1ess extreme draw-down cycl e.It is
expected that the Devil Canyon reservoir will develop
E-3-130
.-r
2.3 -Anticipated Impacts to Aquatic Habitat
resident POlXll ations of 1ake trout,Dolly Varden,
burbot,whitefish ~nd other species.Arctic grayling
will occur in and at the mouths of clear-water tribu-
tari es.
(ii)Devil Canyon Dam to Talkeetna
-Mainstem Habitats
Flow in approximately 1.5 mile (2.5 km)of river
between the dam and the powerhouse outlet will be
el iminated.Depending on backwater effects,thi s
will result in a dry channel for approximately 3300
feet (1000 m)below Devil Canyon dam.The gradient
below the dam is qu ite steep and the bed is com-
posed of coarse substrates.The area is presently
thought to provide marginal habitat for resident
fish.
As described in Section 2.3.1(c),use of mainstem
habitats may significantly change during operation
of the Watana dam.Downstream from the Devi 1
Canyon dam tailrace,however,there would likely be
little additional changes in mainstem habitat use
during the open-water season.Flow reductions in
July and August of 9 and 6 percent,as compared to
Watana alone,may sl i ghtly increase the magnitude
of effects identified under operation of Watana
dam.
Under operation of Devil Canyon dam,winter water
temperatures in the Devil Canyon to Talkeetna reach
wi 11 be increased.The ice front is expected to
form between Talkeetna (RM 99)and Sherman (RM
130);thus,the staging and backwater affects asso-
ciated with an ice cover would not occur upstream
from RM 130 in this portion of the river (Chapter
2,Section 3.4.3[bJ).Winter temperatures in the
reach from Devi 1 Canyon to Talkeetna are expected
to range from 0 to 1.5°C (32.0 to 34.rF)during
the operation of the Watana dam.Outflow tempera-
ture from Devil Canyon dam will be 2 to 4°C (35.6
to 39.2°F),with downstream temperatures ranging
from 0 to 3°C (32 to 37.4°F).Although this is
only a slight increase over natural conditions,it
will often preclude an ice cover on most of the
river above Talkeetna.Impacts resulting from
altered ice conditions are discussed under
Operation of Watana Dam (Section 2.3.1(c)[ii]).
E-3-131
2.3 -Anticipated Impacts to Aquatic Habitat
-Side-Channel Habitats
Side-channel habitats are expected to sustain
impacts similar to those predicted for mainstem
habitats under operation of Devil Canyon dam.
Slough Habitats
The predicted streamflows during the open-water
season under ope rat i on of Devil Canyon are not
expected to have significant affect on slough habi-
tats over those affects related to Watana operation
alone.The slough habitats will have had approxi-
mately nine years to adjust to the Watana opera-
tional flow r~gime during construction of the Devil
Canyon dam.Changes in flow at Gol d Creek from
Watana alone to Watana and Devi 1 Canyon are 1 i sted
in Table E.3.35.During the open water season.
average monthly flows at Gold Creek will be reduced
by 16 and 13 percent in May and June.respectively;
and by 9 and 6 percent in July and August.respec-
tively.Average September flows at Gold Creek will
be 7 percent greater with the ope rat i on of both
dams and duri ng October wi 11 be 3 percent 1 ess.
Thus.open-water season stream flow changes due to
the operation of Devil Canyon dam are not anticipa-
ted to be significant to the slough habitat.Al-
teration of the thermal regime during winter will
affect a greater number of sloughs than under op-
eration of Watana.but effects are expected to be
similar to those discussed in Section 2.3.1(c)
[iiJ).
(iii)Talkeetna to Cook Inlet
No additional impacts are expected to occur in this
reach as a result of operat i on of Devil Canyon dam.
The physical changes to habitats downstream from
Talkeetna resulting from the operation of Watana dam
woul d 1 i kely remai n the same when Devi 1 Canyon dam
commences operat i on"A compari son of proposed down-
stream flows for Watana dam alone and with the addi-
tion of Devil Canyon is presented for Sunshine Sta-
tion in Table E.3.36.Changes in streamflow range
from a reduct i on of 7 to an increase of 11 percent.
Changes in flow of this magnitude are not expected to
result in effects different from those identified
under the operation of Watana dam.The addition of
Devil Canyon is not expected to result in substantial
E-3-132
2.3 -Anticipated Impacts to Aquatic Habitat
changes in water temperatures,water qual ity,or
sediment transport in this reach.Thus,the addition
of Devi 1 Ca nyon dam is not expected to resul tin
adverse effects on fishery resources associated with
habitats below Talkeetna.
(i v)Estuary
The operation of Devil Canyon dam is not expected to
impact the estuary.Physical changes occurring under
operation of Watana alone would essentially remain
the same under the operation of both dams.
(d)Summary of Impacts Associated with
Devil Canyon Dam
(i)Construction Impacts
As with Watana dam,the most significant long-term
impact associated with Devil Canyon dam will be the
increase in fishi ng pressure.Other impacts resul t-
ing from construction activities will be transitory
and are not expected to significantly affect fish
populations.
(i i )Reservoir Filling
Filling the Devil Canyon reservoir will inundate
portions of clear-water tributaries,two of which
(Tsusena and Fog Creeks)presently provide summer
habitat within the reaches to be inundated for
approximately 1200 grayl ing longer than 8 inches
(20 cm)•Aq uat ic ha bit at sin the res er v0 ira re
expected to support more productive resident fish
popul ati ons than those in the Watana reservoi r be-
cause of the timing and magnitude of the annual draw-
down cycle.The reservoir will be filled in approxi-
mately 5 to 8 weeks without impacting downstream
flows.Downstream impacts are not expected during
this period.
(iii)Operation Impacts
No si gni fi cant impacts a re expected upstream from
Devil Canyon dam.The reservoir is expected to
support populations of lake trout,Dolly Varden,
Arctic grayling,burbot,whitefish,and longnose
sucker.
E-3-133
2.3 -Anticipated Impacts to Aquatic Habitat
The most significant downstream impact resulting from
the addition of Devil Canyon dam will be the change
in winter water temperature,which will cause the ice
front to form between Talkeetna (RM 99)and Sherman
(RM 130)instead of between Sherman (RM 130)and
Portage Creek (RM 149)as with Watana alone.The
ri ver stage in the open-water reach wi 11 be lower
than the stage present under an ice cover.This
change will reduce available habitat in areas that
previously formed an ice cover,as was discussed for
impacts associated with Watana dam (Section
2.3.1{c)).
Additional impacts to habitats between Talkeetna and
Cook Inlet are not expected.
2.3.3 -Impacts Associated with Access
Roads,Site Roads,and Railroads
(a)Construction
(i)Construction of Watana Access
Road and Auxiliary Roads
The main access to the Watana damsite will be from
the Denali Highway (Alaska Power Authority 1982a).
The Watana access road will depart the Denali Highway
at Milepost 114 and will run 41.6 miles (69.3 km)
south to the dam-and campsites.The northern por-
tion of the route traverses high,rolling,tundra-
covered hills.The road will cross numerous small
streams such as Lily Creek,Seattle Creek,and
Brushkana Creek (Table E.3.20).The northern
streams,which are part of the Nenana River drainage,
contain grayling and probably other resident species.
The southern part of the road will cross and parallel
Deadman Creek,which also contains grayling and other
resident species.
The gravel road wi 11 have a crown wi dth of 24 feet
(7.3 m).Before road construction is begun,a corri-
dor at least 10 feet (3 m)wide on either side of the
road itself will be cleared.
Short access roads wi 11 be needed to reach materi al
sites and disposal sites.The locations and align-
ments of these auxiliary access roads will be deter-
mined when material sites and disposal sites are
identified during final road design.
E-3-134
-
-
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2.3 -Anticipated Impacts to Aquatic Habitat
Access construction will also involve upgrading the
Denali Highway from Cantwell to the intersection with
the Watana access road,a distance of 21.3 miles
(35.5 km).Upgrading will include straightening road
curves,improving one bridge,and topping the road
with more gravel.
Within the project area,the Denali Highway crosses
several small drainages,side channels of the Nenana
Ri ver,Edmonds Creek,and Jack Ri ver.Jack Ri ver
contains grayling and the Nenana River in this region
supports several species of resident fish (Table
E.3.19).
Any bridge work or straightening associated with road
upgrading will have potential impacts similar to
those resulti ng from new construction.Extension
of culverts in places where the road is widened could
affect fish passage.
-Alteration of Waterbodies
Stream crossings can be a cause of adverse impacts.
Bridges and culverts used to cross streams
containing primarily grayling on the main jaccess
road need to be properly si zed and bedded to ,ensu re
fish passage.This subject is discussed further in
Section 2.4.3.Other causes of adverse road
construction impacts can result from the
following:
•Clearing
Areas of dense or tall vegetation will have to be
cleared before road building begins.In some
upland areas with tundra vegetation,clearing
will be minimal.Clearing causes degradation of
habitat when:
Cleared areas by streams and lakes are not
stabilized and erode into the water body;
Cleared material is pushed into water bodies
causing blockage of fish movements,deposition
of organics on substrates,and localized
erosion;and
Cl eari ng along streams affects cover,avail-
ability of food organisms,and temperatures in
the stream.
E-3-135
2.3 -Anticipated Impacts to Aquatic Habitat
In-Stream Activity
During road construction,it is often necessary
for heavy equi pment to enter water bodi es.Th i s
can alter the substrate and can cause local
turbidity and sedimentation problems •
•Erosion
Erosi on can result from in-stream use of heavy
equipment,placement of fill with high organic
and/or fi nes content,1 ack of stabi 1i zat i on or
revegetation on fills and cuts,and inadequately
placed or sized culverts.The increased sedimen-
tati on that may resul t can degrade downstream
habitats.
•Fi 11 Pl acement
Fills that are placed within floodplains and
streams can remove habi tat previ ously used by
fi she The severity of the impact depends upon
the type and amount of habitat covered.
Roads can block sheet flow to or across wetlands.
When a road with insufficient drainage bisects a
wetland,one side becomes ponded while the other
side dries.The change in water quantity affects
the vegetati on and the nature of the wetl and.
Some wetlands that are contiguous with streams
provi de reari ng habitat for juveni 1e fi she If
the wetlands are dewatered,that habitat can be·
reduced or lost.Potential alterations of sheet
flow are being considered during the detailed
road design.
-Changes in Water Quality
As with dam construction,impacts on water quality
during road construction will result mainly from
erosion and petroleum product spills.Erosion may
occur as the result of excavation for placement of
drainage structures in streams,runoff from borrow
sites,or unstabilized fills,placement of material
within water bodies,and heavy equipment operating
within streams.The road wi 11 primarily affect
small,clear-water systems.
E-3-136
-
-
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2.3 -Anticipated Impacts to Aquatic Habitat
$i nce the systems to be crossed by the road are
clear-water grayl i ng st reams,t hey wi 11 be among
the habitats more sensitive to increase in turbi-
d.ity and petrol eum products.Chronic or 1arge
spills into these streams during construction could
have severe effects upon the biota,either causing
mortal iti es or causi ng fi sh and thei r food orga-
nisms to avoid contaminated areas (Maynard and
Weber 1981;Weber et al.1981).When equipment is
operated in streams or refueling of equipment takes
place within a floodplain,petroleum products are
likely to enter the water.
-Disruptions of Fish POfXJlations
Fish will tend to avoid areas where in-stream work
is bei ng conducted,areascontami nated by petrol eum
products or,depending on the circumstance,areas
experiencing excessive turbidity.Barriers to fish
movements and migrations are created when streams
are diverted,flumed;or blocked during installa-
t ion of drainage st ructu res.Fi sh can also be pre-
vented from moving upstream if drainage structures
are incorrectly installed.Pumping of water from
streams can adversely affect local pOfXJl ations by
entraining juvenile fish.
Du ring road construction,the area between the
Denali Highway and the Watana damsite will be
occupied by hundreds of workers.Although this
area has been recreationally utilized in past
years,it has never experienced such a large influx
of peopl e.Unl ess controll ed,thi s influx will
increase fishing pressure on the streams and lakes
in the area.
(i i)Construction of Devil Canyon Access
Road and Auxiliary Roads
Access to the Devil Canyon damsite will be by road
north of the Su sitna Ri ver from Watana and by rail
from Gold Creek along the south side of the $usitna
Ri ver.The road wi 11 depart from the Watana road
north of the Watana townsite at 38.5,and will
parall e 1 Tsusena Creek for approximately 1.5 mil es
(2.5 km).The route then roughly follows the
2900-foot (878-m)contour west to Devil Creek.The
road turns south along Devil Creek for about 2 miles
(3 km)and proceeds southwesterly to intersect the
E-3-137
2.3 -Anticipated Impacts to Aquatic Habitat
Susitna River at approximately RM 150,where the road
crosses the Su sitna and parall el s an unnamed creek
for a short distance,ending at the construction camp
and village site.The road between Watana and Devil
Canyon will be constructued in the same manner as the
segment from the Denali Highway (see Section
2.3.3[a][i])•
The Devil Canyon access road traverses high tundra
throughout most of its length.Dense shrub vegeta-
tion and trees are encountered when the road nears
the SU sitna Ri ver crossi ng downstream from Devil
Canyon.The road crosses numerou s small streams
between Tsusena and Devil Creeks.Tsusena Creek
contains grayling and possibly cottids and whitefish.
Devil Creek may support populations of grayling,
suckers,cottids and whitefish.Between Devil Creek
and the Susitna River,there appear to be few areas
that provide habitat for fish.The road between
Watana and Devi 1 Canyon wi 11 be constructed in the
same manner as the Denali to Wat~na segment.
The railroad access will depart from existing rail-
road at Gold Creek and proceed north and east to the
construction campsite.It will remain on the south
side of the Susitna River.The railroad will cross
Gold Creek,which is known to contain chinook salmon
(ADF&G 1982a),and wi 11 cross several tributari es
that enter the Susitna River between Gold Creek and
Jack Long Creek (Table E.3.21).It is probable that
these tributaries do not contain fish,but they may
be an important source of clear water for Slough 19,
which is a spawning area for salmon (Figure E.3.16).
The railroad will then parallel Jack Long Creek for
approximately 3 miles (5 km).Jack Long Creek has
been documented to contain pink,coho,chinook,and
chum salmon.The railroad terminus and turnaround at
Devil Canyon will be adjacent to the upper reaches of
Jack Long Creek.
-Alterations of Waterbodies
Impacts to aquatic habitat will result from stream
crossings and other instream activities.Flood-
plain and side-channel habitat in Devil Creek,
Tsusena Creek,and Jack Long Creek could be affec-
ted by road and railroad alignment.Stream cross-
i ngs and drai nage structu res are di scu ssed in Sec-
tion 2.4.1(c).Impacts identified for the Denal i
Hi ghway to Watana segment are al so appl icabl e to
the Devil Canyon access.
E-3-138
2.3 -Anticipated Impacts to Aquatic Habitat
Railroad construction between Devil Canyon and Gold
Creek woul d have impacts simi 1ar to road construc-
tion:aquatic habitat will be affected by fills,
clearing,and stream crossings.
-Changes in Water Quality
It is expected that water quality will be affected
by turbidity and petroleum product spills as was
discussed for Watana access.
-Disruptions of Fish Populations
Fish populations in areas affected by the Devil
Canyon road,auxiliary roads,or the railroad will
experience disruptions similar to those.previously
described for Watana access.
(b)Use and Maintenance of Roads
(i)Use and Maintenence of Watana
Access Road and Auxiliary Roads
-Alteration of Waterbodies
Impacts on waterbodies during road operation will
occur as a result of continued maintenance
activities.Maintenance involves road grading and
replacement of material.Improper maintenance
techniques can result in gravel being pushed off
the roadway into streams and wetlands and in
increased erosion.Road maintenance will have a
greater impact on the small er streams,such as
Deadman Creek,than on the Susitna River.
Thi s secti on consi ders only the road secti on from
the Denali Highway to Watana dam;therefore,
impacts resulting from road construction will be
confined to streams along this road alignment.
-Changes in Water Quality
During continued road use,changes in water quality
can occur as a result of fuel spills and erosion
from poorly stabilized road surfaces and fill
areas.Large fuel spi 11 s woul d have the greatest
impact on the aquatic habitat.
E-3-l39
2.3 -Anticipated Impacts to Aquatic Habitat
The Watana access road will cross numerous streams,
many of which contain grayling.In areas where the
road crosses or encroaches on a waterbody,an
accident involving transport vehicles,including
those carrying petroleum products,could occur.
The impacts associated with spills will depend upon
the season,the type and amount of substance
spilled,the size of the waterbody into which the
spill occurs,and the fish species present.
Erosion from unstable road cuts could be locally
chronic;however,these activities are not expected
to cause major impacts.
-Disturbance to Fish Populations
Fi sh have been known to avoid areas contami nated
with petroleum products (Maynard &Weber 1981;
Weber et ale 1981)and areas of excessive sedimen-
tation or turbidity.Chronic seepage of oil into
streams or lakes could render some areas unusable.
Fish impasses caused by either physical or velocity
barriers have been discussed under Section
2.3.3(a)(i)•
The greatest source of adverse impacts upon fish
populations will be the increased access"ib"ility of
fish streams and lakes to fishing pressure via the
network of access roads.Without appropriate
management strategy,this will be a greater impact
than that resulting from operation of the camp.
As stated in Section 2.3.3(a)(i),the Watana access
road will cross Brushkana,Lily,Seattle,and Dead-
man Creeks as well as other small,unnamed streams.
These creeks are cl ear-water streams and many are
inhabited by grayl ing.Deadman Creek,in parti cu-
lar,is known for its large and abundant population
of grayl ing.The reach of Deadman Creek between
the fall s and Deadman Lake is consi dered prime
grayling habitat.By subjecting this stream to
increased fishing pressure,many of the larger,
older fish will be removed from the population,
altering the age structure and possibly reducing
reproductive potential.A similar impact may occur
to other grayling streams in the area.
E-3-140
.-.
.....
"...,
I
,....
"
2.3 -Anticipated Impacts to Aquatic Habitat
(ii)Use and Maintenance of Devil Canyon
Access Road,Site Roads and Railroad
Aquatic habitat and fish po~lations will be influ-
enced by the existence of roads and railroads through
activities such as road traffic and road
mai ntenance.
-Alteration of Waterbodies
The majority of adverse impacts will have occurred
during road construction.Activities such as road
grading and replacement of drainage structures will
continue to affect stream systems.
-Changes in Water Quality
The "impacts on water qual ity that may occur during
operation of the Watana access road,are also
applicable to the Devil Canyon access road and site
roads.
-Disruptions of Fish Po~lations
Disruptions of fish po~lations resulting from
operation of the Devil Canyon access road,auxil-
iary,roads,and railroad most likely will be:
avoidance of areas of unacceptable turbidity,sedi-
mentation,and contamination;blockages of fish
passage,and increased accessibility to lakes and
streams for fisherman.
2.3.4 -Transmission Lines Impacts
(a)Construction of Transmission Line
-
(i)Watana Dam
The transmission 1ine will be built from Watana dam
to Gold Creek along the Devil Canyon access road and
railroad s~r.At Gold Creek the transmission system
will converge with the Anchorage-Fairbanks intertie,
which extends from Willow to Healy.The route south
of Wi 11 ow wi 11 extend to Poi nt MacKenz ie where a
submarine cable will cross Knik Arm.The terminus of
the southern leg will be the University substation in
Anchorage.The northern leg will extend from Healy
to Ester near Fairbanks.
E-3-l4l
2.3 -Anticipated Impacts to Aquatic Habitat
The transmission line will consist of a series of
steel towers spaced approximately 1300 feet (393 m)
apart that su pport conductors.In thi s case,the
towers wi 11 be x-framed guyed towers that can carry
three conductors.From Watana to Gold Creek,there
will be two parallel sets of towers.At Gold Creek,
two lines will go to Anchorage and one to Fairbanks.
This will necessitate construction of one new line
parallel to the existing intertie between Willow and
Healy and one new 1 ine north of Healy and two new
1 ines south of Willow.With the addition of the
Devil Canyon dam,two more lines will be built from
Devil Ca nyon to Gold Creek.Th is wi 11 resu It in an
arrangement of four parallel sets of towers along
this segment of the lines.
From Watana to Devil Canyon,a 300-foot (90-m)wide
right-of-way will be designated.The Devil Canyon/
Gold Creek segment will require a 51O-foot (l53-m)
wide right-of-way.Within the right-of-way,trees
and shrubs within 55 feet (16.5 m)of the tower cen-
terline will be cleared as well as any other trees or
shrubs that may hamper construction or pose a threat
to the completed line.The width of a 3-line corri-
dor will be approximately 400 feet (120 m)(Common-
wealth et ale 1982).
-Alteration of Waterbodies
Adverse impacts to waterbodies will result
primarily from clearing stream crossings,road
building,and other instream activities associated
with installation of the towers and conductors.
Permanent roads may be built to provide all-season
access.The effects of clearing a right-of-way,
and heavy equipnent traffic on an aquatic
environment have been previously discussed.
The transmission line can be divided into four seg-
ments:central (Watana to Gold Creek),intertie
(Willow to Healy),northern (Healy to Ester),and
southern (Wi 11 ow to Anchorage).In the central
section,the line will closely parallel the Watana-
Devil Canyon access road and railroad S(X1r for ITllch
of its length.It will cross Tsusena Creek,Jack
Long Creek and several small tributaries of the
Susitna River.The impact of constructing a trans-
mi ssi on 1i ne through thi s area wi 11 be simil ar to,
but 1ess than,that of the access road.See Sec-
tion 2.3.3 for a description of river and streams
to be crossed in the central segment.
E-3-142
.....
""'"
.....
r
!
-
.....
-
2.3 -Anticipated Impacts to Aquatic Habitat
The Anchorage-Fairbanks Intertie is being built as
a separate project and will be completed in 1984
(Commonwealth et al.1982).The Susitna project
will add another 1i ne of towe rs withi n the same
right-of-way.The impacts will be similar to those
experienced during intertie construction.The
Envi ronmental As sessment Report for the i ntert ie
(Commonwealth et al.1982)discusses the expected
environmental effects of transmission line
construction in this segment.Fish streams that
will be crossed include the Nenana River,Talkeetna
River,Chuni la Creek,Susitna Ri ver,and the
Kashwitna River.
In the southern segment,the transmission line will
begin at the Willow substation approximately 0.5
mile (0.8 km)north of Willow Creek.Proceeding
fi rst west then south,the 1 ine will be routed
between the Susitna River and the Nancy Lake area,
passing within 0.75 mile (1.3 km)of the Susitna
River.It will cross several Susitna River tribu-
taries,including Fi sh Creek at Approximate
Milepost (AMP)18,before crossing the Little
Susitna at AMP 26.Few streams are crossed between
the Li ttl e Susitna Ri ver and Knik Arm at AMP 44.
Knik Arm,which is approximately 2.5 miles (4.1 km)
wide at that point,will be crossed by a submarine
cable.The Knik Arm switching station is located
between Sixmile Creek and Eagle River.From there
the transmission line bypasses Otter Lake,and
crosses the Alaska Railroad and Fossil Creek.
After crossing the Davis Highway it parallels the
Glenn Highway for about 2 miles (3 km).Ship Creek
is crossed at AMP 75 and the 1i ne traverses the
Chugach Foothi 11 s before termi nat i ng at the
University substation near the corner of Tudor and
Muldoon Roads.Table E.3.22 presents a list of
maj or streams to be crossed and the speci es that
inhabit them.
The streams and fi sh .speci es for the northern 1eg
are listed in Table E.3.23'-.The northern portion
begins at the'Healy substation and immediately
crosse s the Nenana Ri ver,proceedi n9 west to Dry
Creek at AMP 4.75.The 1i ne turns north at thi s
point and roughly parallels the Parks Highway for
the greatest part of its 1ength.The Nenana Ri ver
is crossed again at AMP 2.75 and AMP 58.75.The
line ends at the Ester Substation (AMP 94.25).
E-3-143
2.3 -Anticipated Impacts to Aquatic Habitat
During the transmission line construction,it will
be necessary for heavy equipment such as hydroaxes
and drill rigs to cross streams.Several factors
will influence the severity of impact on the
aquatic habitat.
-Season in which construction takes place;
-Size of the stream;
-Type of habitat in the crossing area;
-Species present;
-Frequency of crossing;
-Type of crossi ng,i.e.temporary bridge,tempo-
rary culvert,low water crossing;
-Streambank configuration;and
-Streambed composition.
It is expected that small,confined streams will be
more susceptible to adverse impacts from transmis-
sion line construction than will larger streams.
If lIall-weather"access is maintained for the
transmission line,a gravel road will be built
along its entire length and permanent stream cross-
ings installed,with attendant,long-lasting im-
pacts.The road and stream crossings will have to
be monitored to ensure that fish passage is main-
tained and aquatic habitat is not degraded.Al-
though the transmission corridor would be many
times longer than the access road previously de-
scribed,the range of possible impacts is similar.
The access points for construction of the transmis-
sion line will be decided during the detailed de-
sign.The Will ow to Healy section will probably
use access established during construction of the
Intert i e.It is 1 ike ly that access will requi re
crossing streams and wetl ands and thus will expand
the area in which adverse impacts may occur because
of transmission line construction.
Details of the installation of the cable under
Knik Arm are to be developed during final design.
Knik Arm is primarily a migration route for anadro-
mous species that util ize the Knik and Matanuska
River drainages including all five species of
Pacific salmon,Dolly Varden,eulachon,and Bering
cisco.Benthic organisms and other resident spe-
cies are sparce because of the excessive amounts of
E-3-l44
-
2.3 -Anticipated Impacts to Aquatic Habitat
glacial material on the sea floor.It is unlikely
that alteration of this area will have any effect
upon resident or anadromous species.
-Changes in Water Quality
It is expected that temporary increases in turbid-
ity and sedimentation will occur in streams sub-
jected to instream activities during construction
of the transmission line.Small,clear water sy-
stem populations will most likely be affected to a
greater extent than will large systems.The
effects are not expected to be long-term.
In addition,streams that are crossed will be ex-
posed to possible contamination by petroleum pro-
ducts due primarily by vehicle accidents.
-Di~turbant~of Fish Populations
Avoidance reactions associated with increased tur-
bidity may occur.Fi sh will a1 so avoid areas where
instream activities occur and,depending upon the
timing,migrations may be affected.Where the
transmission lines cross a stream,clearing may re-
move overhanging vegetation that provides cover for
fi she
Construction of the line will open areas to in-
creased fi shi ng.Duri ng constructi on,thi swill
most likely be confined to workers.The effects
will be greater in the northern and central seg-
ments where access has previously been limited.
(i i )Devi 1 Canyon
With the addition of Devil Canyon dam,two additional
lines will be built from Devil Canyon to Gold Creek.
Si gnifi cant new impacts are not expected with thi s
incremental addition.
(b)Ope~ation of the Transmission Line
(i)Watana Dam
Once the transmission line has been built,there will
be few activities associated with routine maintenance
of towers and lines that could adversely affect
aquatic habitat.However,maintenance of all-weather
roads would entail efforts similar to that for the
.access road.
E-3-145
2.3 -Anticipated Impacts to Aquatic Habitat
-Alteration of Waterbodies
Some localized habitat disruption could occur when
maintenance vehicles need to cross wetlands and
streams to repair damaged 1 ines or towers.Where
roads are not built in conjunction with trans-
mission lines,revegetation is allowed to proceed
to a certain extent around the towers.The vegeta-
tion is usually limited to grasses and shrubs and
small trees by selective clearing so that vehicles
are able to follow the cleared area associated with
the lines.Streams may need to be forded in order
to effect repairs.Depending on the season,cross-
ing location,type and frequency of vehicle traf-
fic,aquatic habitat in the immediate vicinity of
the crossing could be affected.In addition,down-
stream reaches may be affected by increased sedi-
mentation caused by erosion.
-Changes in Water Quality
Changes in water quality during maintenance of the
transmission 1 ines are 1 ikely to result from in-
creased turbidity,instream activities and fuel
contamination.
-Disturbance to Fish Populations
Instream activities associated with line repair and
maintenance could cause disruptions of fish popula-
tions in 1 imited areas.The greatest disruption
will result from the increased accessibil ity to
some fishing areas from the cleared transmission
corridor.Because the vegetation is kept rela-
tively low,hikers and all terrain vehicles can use
the corridors as trails.In winter,snow machines
will also be able to traverse these cleared areas.
Th i s wi 11 resu 1tin greater numbers of fi shermen
bei ng abl e to reach areas the previ ou sly experi-
enced little or no fishing pressure.This effect
will be more acute in areas where the new trans-
mission route diverges from existing roads and
transmission lines,such as south of Willow and
north of Healy.The area between Healy and Willow
will have been subjected to disturbance and in-
creased pressure during construction of the
Anchorage/Fairbanks intertie.Any increased fish-
ing pressure along the intertie as a result of the
E-3-146
~i
-
-
-
2.4 -Mitigation Issues and Mitigating Measures
Susitna lines being added to the corridor will pro-
bably be minor.The presence of an operating cable
under Kni k Arm shoul d cause no impacts to fi sh
popul at ions.
(i i )Devi 1 Canyon
The addition of two additional lines is not expected
to result in significant incremental maintenance
impacts over the Watana-only scenario.
2.4 -Mitigation Issues and Mitigating Measures
2.4.1 -Approach to Mitigation
The objecti ve of fi sheri es mit i gat ion pl anni ng for the Su sitna
Hydroelectric Project is to provide habitat of sufficient quality
and quantity to mai nta in natural reproduci ng popul ati ons where
compatible with project objectives.This is consistent with the
the mitigation goal s of the USFWS and the ADFG.In order to
accomplish this objective,the Power Authority will avoid,mini-
mize,or rectify impacts.In situations where it is not feasible
to mitigate the impact in this manner,the Power Authority will
provi de compensati on through propagat ion facil it i es.The fi rst
preference will be through habitat improvement measures to i n-
crease the productivity of the habitat or to provide additional
habitat within the Susitna Basin.As the last resort,fish pro-
pagation facilities would be proposed as compensation.
The priorities of the fisheries mitigation,as discussed in
section 1.3,were determined by employing the hierarchical
approach to mitigation contained in the Susitna Hydroelectric
Project,USFWS and ADF&G mitigation pol icies.The five basic
mitigative actions,in order of priority,are:
-Avoiding impacts through design features or scheduling activi-
ties to avoid loss of resources.
-Minimizing impacts by carefully schedul ing and locating opera-
tions,timing and cOfltrolling flow releases,and controlling
impacts through best management practices.
-Rectifying impacts by repairing disturbed areas to provide
optional fish habitat and reestablishing fish in repaired
areas.
-Reducing or eliminating impacts over time through monitoring,
maintenance,and proper training of project personnel.
E-3-147
2.4 -Mitigation Issues and Mitigating Measures
-Compensating for impacts by conducting habitat construction
activities that rehabil itate altered habitat or by managing
resources on project or nearby public lands to increase habitat
values.
Each of the foll owi ng impact issues is addressed in terms of
these five mitigation actions.Table E.3.38 summarizes mitiga-
tion features for major impact issues associated with operation
of the project.The proposed mitigation program and associated
costs are in Table E.3.39.The schedule for implementing this
program is in Table E.3.40.
2.4.2 -Selection of Project Evaluation Species
Selection of evaluation species is a necessary step in assessing
impacts and in developing mitigation plans.Various species and
life stages have different critical life requirements and respond
differently to habitat alterations.A change in habitat condi-
ti ons that benefits one speci es or 1 He stage may adversely
affect another,and mitigation plans for one species may conflict
with those proposed for another.Selection of evaluation species
can provide a mechanism to resolve potential conflicts and to
focus the resources available for analysis and planning.
The evaluation species were selected after initial baseline stu-
dies and impact assessments had identified the dominant species
and potential impacts on avail able habitats throughout the year.
Mitigations were then developed that will reduce impacts on
habitat parameters that are expected to control populations.
Fishery resources of the Susitna River and activities associated
with the project proposal were reviewed.Evaluation species were
selected on the basis of the following criteria:
-High human use value;
-Dominance in the ecosystem;and
-Sensitivity to project impacts.
Species with high regional visibility and commercia],sport,sub-
sistence,or aesthetic value were given priority.Within this
category,species sensitive to project effects were highly rated.
Si nce the eval uat i on speci es pl ay a dami nant rol e in the eco-
system,they may serve as indicator species.By maintaining cri-
tical habitats for evaluation species,many of the potential im-
pacts on less sensitive species or species with a lower
evaluation priority will be mitigated.
E-3-148
r--
-
F,
-
-
2.4 -Mitigation Issues and Mitigating Measures
Based on the aquatic studies baseline reports,impact assess-
ments,and harvest contributions,four species of Pacific salmon
(chum,chinook,coho,and pink)were identified as evaluation
species for the Susitna River downstream from Devil Canyon.
Arctic grayling was selected as the evaluation species for the
impoundment.
Since the greatest changes in downstream habitats are expected in
the reach between Devil Canyon and Talkeetna,fish using that
portion of the river were considered to be the most sensitive to
project effects.Because of differences in thei r seasonal habi-
tat requirements,not all salmon species would be equally
affected by the proposed project.Of the five species,chum and
sockeye salmon appear to be the most vulnerable in this reach,
because of their dependence on slough habitats for spawning,in-
cubation and early rearing (Sections 2.2.1 and 2.2.2).Of the
two species,chum salmon are the dominant species (Section
2.2.1).The sockeye that spawn in the sl oughsupstream from
Talkeetna,however,are considered to be strays from stocks in
the Chulitna and Talkeetna drainages (ADF&G 1983).Since these
sockeye do not appear to support a viable stock,they are not
included as an evaluation species.Chinook and coho salmon,are
less likely to be impacted by the project because most of their
critical life stages,such as spawning,incubation,rearing and
overwintering,occur in habitats that are less likely to be
altered by the project (Section 2.3.1).While some pink salmon
spawn in slough habi tats in the reach between Devi 1 Ca nyon and
Talkeetna,the majority of these fish utilize tributary habitats.
The mitigations proposed to maintain chum salmon productivity
should allow sockeye and pink salmon to be maintained as well.
The chinook and coho salmon juveniles rear in the river for one
to two years prior to out-migration with much of the rearing
apparently occurring in clear water areas,such as in sloughs and
tributary mouths.Improved conditions in the mainstem are
expected to provide replacement habitat to mitigate for the
potential loss of rearing areas in slough habitats.Juvenile
overwintering habitats are not expected to be adversely
affected.
The greatest change to resident fish will occur in the impound-
ment zone.In the impoundment zone,arctic grayling were se-
lected as the evaluation species because of thei r abundance in
the area,their sensitivity to impacts during all seasons and
life stages,and their desi~ability as a sport fish.
In summary,the evaluation species and life stages selected for
the Susitna Hydroelectric Project are:
E-3-149
2.4 -Mitigation Issues and Mitigating Measures
(a)Devi 1 Canyon to Cook Inlet Reach
(i )Chum Salmon
-Spawning adults;
-Embryos and pre-emergent fry;
-Emergent fry;
-Returning adults;and
-Out-migrant juveniles.
(i i )
Chinook Salmon
-Rearing juveniles;and
-Returning adults.
(iii)Coho Salmon
-Rearing juveniles;and
-Returning adults.
(i v)Pink Salmon
-Spawning adults;and
-embryos and pre-emergent fry;
-Emergent fry;
-Returning adults;and
-Out-migrant juveniles.
(b)Impoundment Zone
(i)Arctic Grayling
-Spawning ad~ts;
Incubating embryos;
-Reari ng;and
-Overwi ntering.
2.4.3 -Mitigation of Construction Impacts
Upon Fish and Aquatic Habitats
Mitigation of construction impacts is achieved primarily by in-
corporating environmental criteria into pre-construction planning
and design,and by good construction practices.Incorporation of
environmental criteria into design activities and construction
of the Susitna dams and related facilities will avoid or minimize
impacts to aquatic habitats.A design criteria manual and a con-
struction practices manual are being prepared.The design cri-
teria manual will be available in June 1983,and the construction
practi ces manual wi 11 be one of the fi rst tasks ass i gned to the
construction manager.
E-3-150
.....
2.4 -Mitigation Issues and Mitigating Measures
The aquatic studies program will continue to make major contribu-
tions to pre-construction planning and design.Studies will be
used in siting,design,and scheduling of project facilities and
activities.For example,the final alignment of the Watana
access road will take into consideration the fish streams along
its route.The route is sited to avoid encroachment on streams,
to minimize stream crossings and impacts at required crossings,
and to minimize cut banks.
Biological information will be incorporated into the design cri-
teria and construction practi~es manuals.A high degree of com-
munication and cooperation will be maintained between environ-
mental staffs and design ~nd construction personnel in order to
facilitate integration of biological criteria into designs,
specifi~ations,and construction practices.
Scheduling of construction activities during preconstruction
planning is another means of avoiding or minimizing adverse im-
pacts to fish and aquatic habitats.Whenever possible,activi-
ties will be scheduled to avoid known sensitive periods.
Continued monitoring of the construction facilities and activi-
ties will ensure that impacts to the aquatic envi ronment ,are
avoided or minimized.Monitoring cani dent ify areas that may
need rehabilitation or maintenance and areas where previous miti-
gation measures are proved inadequate and remedial action must be
taken.Costs associated with constructi on mon i tori ng are out-
lined in Table E.3.41.
Potential impacts are identified in Section 2.3.The following
is a discussion of the impact issues and the mitigation measures
that wi 11 be appl ied duri ng and after construction.Those issues
considered to have the greatest potential for adverse impact to
the aquatic environment are discussed first.Avoidance,minimi-
zation,rectification and reduction of impacts are discussed.
There are no direct mitigation costs associated with these miti-
gations.
(a)Stream Crossings and Encroachments
(i)Impact Issue
Imp roperly constructed stream cross i ngs can block
fish movements and/or increase siltation in the
stream.Roads with inadequate drainage structure can
alter run-off patterns of nearby wetlands and
streams.Encroachments on stream courses can alter
hydraul ic characteri sti cs and increase si ltati on of
streams,thereby affecting fish habitat •
E-3-151
2.4 -Mitigation Issues and Mitigating Measures
(ii)Mitigation
The obj ecti ve of constructi ng stream c rossi ngs is to
maintain the natural stream configuration (Lauman
1976)and flow so that passage of fish is assured.
Maintenance of fish passage is required under AS-
16.05.840.Appropriate control measures will be
undertaken as a part of routine maintenance to insure
that beaver dams do not interfere with fish passage
needs.For the project area,the evaluation species
used in developing criteria for stream crossings is
arctic grayling (see Table E.3.42 for criteria to be
applied to stream crossings).In designing and con-
structing a crossing,consideration will be given to
the following presence or absence of fish/fish habi-
tat,location of crossing,type of crossing struc-
ture,flow regime,and method of installation.
-Presence or Absence of Fish/Fish Habitats
Streams havi ng documented fi sh 0 r fish habi tat at
or upstream from the road crossing will be designed
to pass fi she Only those streams without fi sh or
fish habitat at,or upstream from,the road cross-
ing will be designed solely on the basis of hydro-
logic and hydraulic criteria.
-Location of Crossing
Project roads will be aligned and located to
mlnlmlZe the number of stream crossings.When
crossings are unavoidable,they will be located at
a right angle across the stream in a straight
stretch (Lauman 1976),and with narrow,stable
banks that do not requi re cutti ng or excessive
stabilization.The crossings will be located so
that important habitats,such as spawnings beds and
overwintering areas,are not disrupted.
-Type of Crossing Structure
Open-bottom arch culverts will be installed
wherever possible (Figure E.3.24).Multiplate
elliptical and oversized circular culverts can also
be ~sed to maintain the natural streambed (Joyce et
al.1980a;Lauman 1976)and will be used when open
arch culverts are not feasible.Standard-size
circular culverts will only be used in drainages
that are not considered fish habitat.
E-3-152
-
-
-
f"'",
i
2.4 -Mitigation Issues and Mitigating Measures
Log stringer and temporary bridges will be used
where infrequent,light vehicle traffic is
expected.Their use on the Susitna Project will be
1 imited to the transmi ssion 1 ine corri dor.Duri ng
winter transmission line construction,snow and ice
bridges will be used to cross streams.These will
be removed before breakup to avoid blocking stream
flows.
-Flow Regime
Culverts will be designed to allow grayling passage
at critical times using the ADF&G velocity criteria
(Table E.3.42).Multiplate elliptical and
oversi zed ci rcul ar cul ve rt inverts wi 11 be set
below the streambed elevation to avoid perching and
will be armored,when necessary,to minimize
erosi on at the outl et.Natura 1 stream substrate
will be placed on the bottom of the cul verts over
their entire length.
-Methods of Installation
When cul verts other than open-bottom arches are
used,streams will be diverted around the work area
until the crossing is completed.On small systems,
the stream may be flumed.Diversion or fluming
will reduce the amount of siltation downstream from
the construction area.Diversion will be
accomplished using ADF&G criteria (Table E.3.43).
In some areas,roads and transmission li.nes must
parallel a stream or river.The alignment will be
away from the floodplain to the greatest extent
possible.Where this is not possible,the road
will be aligned to preclude channelization of.the
stream.
The transmission towe'rs will be al igned so struc-
tures are out of streams and fl oodpl ai ns to the
best extent practicable.Instream activities will
be confined to installation of drainage structures
on access routes.Where pract i cab le,constructi on
wi 11 be schedul ed for wi nter months when heavy
equipment can cross frozen creeks without elaborate
constructed crossings.
E-3-153
2.4 -Mitigation Issues and Mitigating Measures
(b)Increased Fishing Pressure
(i)Impact Issue
The sport fishing pressure on the local streams and
lake will substantially increase.The access road
and transmission line will allow fishermen to reach
areas previously unexploited.
(ii)Mitigation
During the construction phase,access to the streams
will be limited by closing roads to unauthorized
project personnel and general public.The Alaska
Board of Fisheries will be provided such information
as they require to manage the fisheries.Some water-
sheds,such as the Deadman Creek/Deadman Lake system,
will require modification of current seasons and
catch limits if current stocks are to be maintained.
These regul at ions may take the form of reduced sea-
sons or catch limits,imposition of maximum size
limits,or control of fishing methods.Since public
health regulations will not allow sport-caught fish
to be stored or prepared at public food service faci-
lities,the project policy will be that all fishing
be restricted to catch-and-release unless stated
otherwise by the Board of Fisheries.
(c)Erosion Control
(i)Imp~ct Issue
Sustained high level s of sediment in a system can
change the speci es compos it i on and productivity of
the system (Bell 1973,Alyeska Pipeline Service
Company 1974).Sntation can affect development of
fish eggs and benthic food organisms.
(ii)Mitigation
The primary mitigation measures that will be used to
minimize construction erosion are:(1)locating fa-
cil iti es away from the cl ear water fi sh streams;(2)
employing erosion control measures such as run off
control,stilling basins and revegetation;(3)sche-
duling erosion-producing activities at biologically
noncritical seasons (APSC 1974);(4)minimizing the
time necessary to complete the activity so that ero-
sion is a short-term,non-reoccurring problem;and
(5)maintaining vegetated buffer zones.
E-3-154
2.4 -Mitigation Issues and Mitigating Measures
The natural vegetation is a major factor in
preventing erosion (APSe 1974).Clearing for roads,
transmission lines,and other facilities will be
confined to the minimum area and level necessary.
For transmission lines,only taller trees and shrubs
will be removed;the lower vegetation will not be
disturbed.Adjacent to streams,especially small
systems,cl ea ri ng wi 11 be done by hand.Cl eared
material will be removed from the floodplain to
approved disposal sites,salvaged or burned onsite.
Disposal sites that contain cleared slash and sub-
standard material s (overburden)wi 11 be located in
upland areas away from water bodies.Disposal sites
will be constructed so that neither run off during
breakup nor rainfall will wash silty material into
streams.This may entail run off control structures,
surrounding the disposal site with berms,or
channel i ng run off through contai nment ponds.
To preclude run off from carrying silt to water
bodies near construction sites,drainage control will
direct silty water into settling basins.Clarified
water wi 11 be di scharged into recei vi ng waters in
accordance wi th the Al aska Department of Envi ronmen-
tal Conservation (ADEC)permit requi rements
(AS-46.03.100).
Prompt grading,mulching,and revegetation of cut-
and-fill areas will be used to minimize erosion.
(d)Material Removal
(i )ImpaCt Issue
Removal of floodplain gravel can cause erosion,sil-
tation,increased turbidity,increased ice buildup
caused by ground water overflow,fish entrapment,and
alteration of fish habitat.
""'"'
(i i)Mitigation
Adverse impacts on aquatic habitats will be avoided
or minimized by application of the following guide-
lines which are more fully discussed in Joyce et ale
..(1980a);and in Burger and Swenson (1977).
E-3-155
2.4 -Mitigation Issues and Mitigating Measures
Before floodplain material sites are used,it will be
determined that upland sources are inadequate to
supply the needed material.Floodplain sites will be
thoroughly explored to veri fy that they can supply
the necessary quantities.Important habitats such as
overwintering and spawning areas will be identified
and avoided.
Buffers wi 11 be ret ai ned between the sites and any
active channels except when draglining in the active
channel.Material will be stockpiled outside the
floodplain to avoid backing flow at higher stages and
the possibility of material being eroded into down-
stream reaches.Overburden will be di sposed of in
upland sites or returned to the area from which it
was removed and contoured and planted.
Material washing operations will use recycled water
and will not discharge into adjacent streams.
The Tsusena Creek material site (Borrow Site E)will
be rehabil itated after mining has ceased.The goal
of rehabilitation will be to create productive aqua-
tic habitat.The site will be shaped and contoured
to enhance fish habitat,and all man-made items re-
moved from the site (Figure E.3.25).Exposed slopes
will be graded and seeded.
Rehabilitated areas will be monitored to ensure that
grading,revegetation and other mitigative measures
are effective.The Cheechako Creek and Susitna River
borrow sites will be inundated and will not require
rehabilitation beyond that needed to minimize ero-
sion.
(e)Oil and Hazardous Material Spills
(i)Impact Issue
Spi 11 s of oil and other hazardous substances into
streams are toxic to fish and their food organisms.
(i i)Mitigation
A Spill Prevention Containment and Countermeasure
Plan (SPCC)will be developed as required by EPA (40
CFR 112.7).
E-3-156
.....
.....
2.4 -Mitigation Issues and Mitigating Measures
Equ i Jl11ent refu eli ng or repa i r wi 11 not be allowed in
or near floodplains without adequate provisions to
prevent the escape of petroleum products.Waste oil
will be removed from the site and be di sposed of
u si ng ADEC/USEPA-approved procedu res.Fu el storage
tanks will be located away from waterbodies and
within 1 ined and bermed areas capabl e of containing
110 percent of the ta.nk·volume.Fuel tanks will be
metered and all outflow of fuel accounted for.All
fu el 1 i nes wi 11 be located in abovegrou nd or grou nd
su rface uti 1idors to facil itate 1ocati on of ru ptu red
or sheared fuel lines.
Vehicle accidents,although difficult to fully pro-
tect agai nst,can be mi nimi zed by constructi ng the
roads with properly desi gned cu rves to accommodate
winter driving conditions.The roads will be ade-
quately signed,and during the winter,difficult
stretches will be regu 1arly cl eared and sanded.In
summer,dust ·control will be accomplished with
water.
State 1aw requ i res that all s pi 11 s,no matter how
small,be reported to DEC (18AAC70.080).Personnel
will be assigned to monitor storage and transfer of
oil and fuel and to identify and clean up spilled oil
and other hazardous material.
All personnel employed on the project,especially
field personnel,will be trained to respond to fuel
spi 11 sin acordance with an approved oil splll con-
tingency plan.The plan will include a manual and
training program describing:
-Actions to take as a first line of defense in the
event of a fuel spi 11.
-Persons to contact in the construction organization
and in state agencies.
-Locations of sensitive habitats.
-Location of all oil spill control and cleanup
equiJl11ent,the types of equiJl11ent at each location
and appropriate procedures.
-Records to keep during an oil spill and cleanup
operati on •
E-3-157
2.4 -Mitigation Issues and Mitigating Measures
Oi 1 spi 11 equ i Jll1ent wi 11 be prepositi oned and ade-
quate to handl e the 1argest spi 11 expected.Person-
nel will be trained in the operation of the equip-
ment,and the equipment will be inventoried and
tested regJlarly to make sure it is in proper working
order in the event of an emergency (Bohme and
Brushett 1979;Lindstedt-Siva 1979).
(f)Water Removal
(i)Impact Issue
Fish fry and juveniles can be impinged on intake
screens or entrained into hoses and pumps when water
is withdrawn from water bodies for miscellaneous uses
during construction.
(i i)Mit i gat ion
If possible,surface water withdrawal will be from
streams or lakes that do not contain fish.If water
must be withdrawn from a fish-bearing water body,the
Al aska Department of Fi sh and Game intake design
criteria will be used for all intakes.
The ADF&G criteria are that:(1)all intakes should
be screened;(2)openings in the screen should not
exceed 0.04 sq in;and (3)water velocity at the
screen should not exceed 0.1 ft/sec (0.03 m/sec).No
more than 20 percent of the instantaneous flow wi 11
be removed at any time.
(g)Blasting
(i)Impact I ssu e
Blasting in or near fish streams can rupture swim
bladders and damage incubating embryos.
(ii)Mitigation
The ADF&G has standard blasting guidelines that
establish the distance from waterbodies at which
charges can be detonated without harmi ng fi she
Blasting will be accomplished using these guidelines
(Table E.3.44).
E-3-158
(i i )
-
I'"""
2.4 -Mitigation Issues and Mitigating Measures
(h)Susitna River Diversions
(i)Impact Issue
Fish passing downstream through the diversion tunnels
are expected to be lost because of the hi gh tunnel
velocities.During summer,relatively few fish are
present in the vici nity of the tunnel entrance.
During winter,resident fish are expected to
be entrained into the intake and passed downstream.
Mitigation
The segment of the fish population lost in the diver-
si on tunnel woul d be lost subsequent to reservoi r
filling,because of lost tributary habitat and the
expected low habitat value in the reservoir (see
Section 2.3.1[b]).Mitigation for these losses will
be achieved by the early initiation of grayl ing pro-
pagation,as discussed under Mitigation for Inunda-
tion Impacts in Section 2.4.4(c).
(i)Water Quality Changes
(i )
(i i)
Impact Issue
Discharge of camp effluents result in increased
levels of metals and nutrient loading.Concrete
batching plants release high alkaline effluents.
Mitigation
Effl uents
standards
72.010)•
will comply with ADEC/USEPA effl uent
(AS 46.03.100;18 AAC 70.020;18 AAC
The concrete batching effl uent will be neutral ized
and treated prior to discharge to avoid impacts
related to f)H and toxic substances (see Chapter 2,
Sections 3.2.1(b)[vi]and 3.3.1(b)[vi]).
(j)Clearing the Impoundment Area
(i)Statement of Issue
Ad verse impacts associ ated wi th removing vegetati on
along streams are:(1)accelerated erosion into the
streams;(2)altered temperature regimes;and (3)
operation of equipment in perennial or ephemeral
stream ways.
E-3-159
2.4 -Mitigation Issues and Mitigating Measures
(ii)Mitigation
Clearing will be scheduled as close to reservoir
filling as is feasible.Disturbance to the vegeta-
tive mat will be avoided.Erosion control methods
will be employed wherever needed to mi n,imi ze unneces-
sary erosion to streams.To the extent practicable,
clearing will take place during the winter.Cleared
vegetation will be dried for one season and burned in
place.The construction practices manual will
specify reservoir clearing practices.
2.4.4 -Mitigation of Filling and Operation Impacts
(a)Mitigation of Downstream Impacts
Associated with Flow Regime
(i)Impact Issue
As descri bed in Exhi bit A,the proposed project con-
sists of two stages:the first stage-Watana develop-
ment and the second stage-Devil Canyon development.
Each stage requires its own flow release schedule
during both filling and operation.The flow release
schedule is designed to provide a balance between
filling power generation and instream flow require-
ments of the evaluation species.The initial filling
of Watana reservoi r will take approximately three
years using a flow release schedule,as shown in
Table E.3.26.After filling is complete,Watana dam
power plant will be operated as outlined in Table
E.3.32.Devil Canyon dam reservoir will be filled in
two segments.The fi rst segment wi 11 take approxi-
mately four weeks and the second segment,occurring
one or more years later,will take five to eight
weeks.The operation of the two dam stage will
result in a flow regime as shown in Table E.3.35.
One criterion that influences the establishment of
the flow rel ease schedul e is the choi ce of the key
fi sh speci es and/or 1 ife stage to be protected.In
the reach between Tal keetna and Devil Canyon,chum
salmon were given highest priority followed by
chinook,coho and pink salmon (Section 2.4.2).
As discussed in Section 2.3,a primary fishery con-
cern is the provision of flows between Devil Canyon
and Talkeetna that:
E-3-160
"""
2.4 -Mitigation Issues and Mitigating Measures
Allow adult salmon access to tributary spawning
areas;
Allow adult salmon access to slough spawning
habitat;
Maintain a suitable water depth on the spawning
beds throughout the spawni ng peri ode;
-Maintain flow through the spawning gravels during
the incubation and pre-emergence period;and
-Provide a flow-related stimulus to stimulate the
out-migration of fry.
Additional fisheries toncerns related to instream
flow needs of resident and juvenile anadromous fishes
include the need to:
-Maintain overwintering and summer feeding habitat;
and
Maintain access to tributary spawning and rearing
habitat.
-
(i i )Measures to Avoid Impacts
Adverse impacts to fi shery resou rces resu lt i ng from
flow alteration can be avoided or minimized through
selection of an appropriate flow regime.While
hydroelectric developnents with storage facilities
alter the natural flow regime in the river,changes
in streamflow patterns do not necessarily result in
adverse impacts to fish populations.For example,if
low flows are limiting fish populations,then supple-
ment i ng low flow may resu 1tin enhancement to that
popul ation.
Three factors control water depth at the mouth of the
sloughs:(1)mainstem stage;(2)channel geometry;
and (3)flow in the slough.Of the three factors
contributing to access,the project will only affect
the stage at the mainstem.Thus,to avoid the impact
on access to slough habitats by adult salmon,the
project would have to provide mainstem stages suffi-
cient to freely pass fish into the sloughs.This can
only be accompl i shed by provi di ng the appropri ate
mainstem stage at the sloughs during the spawning
season.Under the proposed flow regime,free access
to sloughs by adult salmon will be impaired and addi-
tional mitigation measures are needed to reduce these
impacts.
E-3-l6l
2.4 -Mitigation Issues and Mitigating Measures
(iii)Measures to Minimize Impacts
A flow release schedule will be used that mlmmlzes
the loss of downstream habitat and maintains normal
timing of flow-related biological stimuli.
During project operation t minimum Gold Creek target
flows from October through Apri 1 will be rna i ntai ned
at 5000 cfs.From May to the 1ast week of July t the
target flow will be increased to 6000 cfs to allow
for mainstem fish movement.During the 1 ast five
days of JulYt flows will be increased from 6000 cfs
to 12 t OOO cfs in increments of approximately 1000 cfs
per day.Flows will be maintained at 12,000 cfs from
August 1 through mid-September to coincide with the
sockeye and chum spawning season in the sloughs
upstream from Talkeetna.
-Winter Flow Regime (October-April)
The wi nter fl ow wi 11 be reduced duri ng October of
the second and third year of Watana filling and
substantially increased during operation of both
project stages.The filling flow regime from
November 1 through April 30 is proposed to reflect
the inflow to the reservoir.Since minor impacts
are expected during filling,no mitigations are
proposed.
The increase in winter flows during operation of
Watana dam,however,are expected to cause substan-
tial increases in stage as the ice cover forms.
Stage increases of 3 to 4 feet (0.9 to 1.2 m)are
predicted.These increases in stage are expected
to overtop the berms at the upstream end of sloughs
and cause rna i nstem water to flow through some
sloughs.As discussed in Section 2.3.1(b)[iii],
thi s woul d 1 ead to reduced temperatu res in the
incubation gravels,increased ice formation and
reduced slough water temperatures in the spri ng.
The impacts associated with slough overtopping
during the winter will be minimized by increasing
the height of the berms at the upstream end of the
most product i ve sloughs downstream from the ice
front (Fi gure E.3.26).The ice front is expected
to form between Sherman (RM 130) and Portage (RM
149)t depending on climate conditions prior to ice
formation (see Chapter 2 t Sect.3.2.).Productive
sloughs that will be overtopped more frequently
than once every five years will be protected.
E-3-162
-
.....
2.4 -Mitigation Issues and Mitigating Measures
It is anticipated that sloughs 8,8A,8B,8C,
Moose,AI,B,9,9A and 11 will need protective
berms.An estimate of costs associated with these
protective berms is given in Table E.3.39.
-Spring Flow Regime (May-June)
Breakup flood flows are reduced in the regulated
flow regimes.The primary species/l ife stage that
woul d be impacted dur-j ng spri ng flows are sal mon
fry.It is hypothesized that the spring breakup
flows may induce salmon fry,particularly chum and
pink salmon,to move out of the sloughs and other
incubation gravels,and begin the process of out-
migration.The effects of spring breakup on fry
migration during the 1983 spring breakup period
will identify the timing of out-migration in rela-
tion to flow.This information will form the
basis for modifying the spring release schedule to
provide a sufficient flow-related stimulus.The
effectiveness of these releases will be evaluated
during the filling and operational monitoring
studies.
-Summer Flow Regime (July-September)
The five species of Pacific salmon enter the spawn-
ing areas during the summer high flow periods.
Most of the spawning in the Devil Canyon to
Talkeetna reach is confined to sloughs and tribu-
taries.Access to the slough spawning areas is
apparently provided by a combination of the high
summer flows in the Susitna River mainstem and the
summer surface inflow to the sloughs.In addition,
the useable spawning area in sloughs is at least
partly controlled by backwater levels from the
mainstem into sloughs.Upwelling ground water in
the sloughs attracts adults,mai ntai ns the perme-
ability of spawning gravels,and provides a stable
winter flow durjng the embryo incubation period.
The primary species/l i fe stage that woul d be
impacted in the summer is adult chum salmon.
The proposed operational flows from August 1 to
September 15 will provide 12,000 cfs at Gold Creek
and will reduce,but not avoid impacts to spawning
salmon.It is anticipated that adult salmon will
still experience difficulty in gaining access to
the sloughs.A refinement of these mitigation
flows is being analyzed.
E-3-163
2.4 -Mitigation Issues and Mitigating Measures
The mitigation increment proposed release for
August 1 to September 15 is approximately 387,000
acre-feet.This water has been allocated to pro-
vide 12,000 cfs downstream flows during spawning
season.At present,this volume is distributed
evenly between July 25 and September 15,when adult
chum and sockeye are returning to slough spawning
areas.Alternatively,this mitigation volume can
be allocated in a series of short-term augmented
discharges of variable magnitude,frequency and
duration that minimize impacts to different species
life stages and maximize use of the available water
volume.The optimal flow regime w"ill be determined
from an analysis of the habitat requirements of the
evaluation species that is currently in progress
through the aquatic studies program.This informa-
tion will contribute to the evolution of the reser-
voir operation regimes.
Even though the use of short-duration pulsed flows
will increase ease of access into sloughs,it is
expected that impacts to spawni ng salmon wi 11 not
be completely avoided through flow allocation.The
flows are of sufficient magnitude,however,to
permit rectifyi ng impacts to salmon spawning
activity.
(iv)Rectification of Impact
-Wi nter Flows
Since impacts are mitigated in the preceeding
section,rectifying measures are not needed.
Sp ri ng Flows
If salmon fry require a high flow at breakup in
order to stimulate out-migration,a properly timed
pulse of sufficient magnitude will be provided.
-Summer Flows
Impacts to salmon spawni ng areas wi 11 occur if
mitigation measures are not employed in coordina-
tion with the proposed project flows (or the alter-
nat i ve regime of short-term augmented fl ows).The
rectification methods selected are (1)to maintain
access to the sloughs;and (2)to ensure suitable
spawning and incubation habitat by physically
modifying the sloughs,to maximize use of reduced
E-3-164
-
r-
i
2.4 -Mitigation Issues and Mitigating Measures
filling and operational summer flows.The follow-
i ng habitat enhancement measures wi 11 be appl i ed
either singly or in combination on sloughs,depend-
ing on the type of impact that limits salmon pro-
duction.These methods,especially if used in
combi nati on wi th short-term augmented flows du ri ng
the spawning season,will maintain salmon produc-
tivity in the sloughs.Sloughs on which rectifying
measures will be used are sloughs 8,8A,88,8C,
Moose,AI,B,9,98,9A,11, 17,and 21.These
sloughs accounted for over 97 percent of the spawn-
i ngchum and 98 percent of the spawning sockeye
using slOUghs in 1981 and 1982.Estimates of costs
associated with these mitigations are provided in
Table E.3.39 •
•Access Mitigation
the project flows during August may not create
sufficient backwater effects at the mouths of
some sloUghs to permit free access by returni ng
adult salmon.Access to these sloughs wi 11 be
facil itated by restructuri ng the ent rance of the
slough to convey the majority of the slough
discharge and thus provide a greater passage
depth (Figure E.3.27).The mitigation plan
provides for eight restructured slough mouths.
After the adults enter some of the sloughs,they
ascend long reaches of shallow water over a steep
gradient before entering the spawni ng pool s..If
the ground water flow is substantially reduced,
the depth of the spawning pools is also likely to
be reduced.In order to rectify these impacts,
the streambed profi le of the impacted sloughs
will be lowered to re-establ ish the head between
the mainstem and slough (Figure E.3.28).Lower-
ing of the slough profile will reestablish the
backwater effect at the mouth of the slough and
allow free passage through the slough and use of
the spawning areas.Lowering of the slough pro-
file will reestablish the area of ground water
upwelling that was reduced by the lower mainstem
flows.Preliminary calculations indicate a
lowering of 1.5 feet (0.5 m)will accomplish the
objectives.The mitigation plan provides for
lowering the profile of eight sloughs.Such
techniques have been successfully used in British
E-3-165
2.4 -Mitigation Issues and Mitigating Measures
Columbia to improve chum salmon spawning
et a1.1980)and are further discussed
Wood Leida1 Association and D.B.
Association (1980).
(Lister
in Ken
Lister
I~I
During the lowering process,the slough will be
structured to optimize spawning habitat (Figure
E.3.28).If it is assumed that 50 percent of the
area in these lowered sloughs will be useable
spawning habitat,then 144,000 square feet
(12,960 m2)of spawni ng habitat will be made
available by this process (Table E.3.46)•
•Spawning Habitat Mitigation
If it is detennined from the ongoing aquatic
studies that the reduction of upwelling area
under operational flows will reduce available
spawning area to the extent that salmon produc-
tivity is decreased,then additional methods will
be employed to augment upwelling in the sloughs.
This will be accompl ished by pi ping water down-
gradient to a series of perforated drainage pipes
to enhance the volume of upwelling in the slough
(Figure E.3.29).The mitigation plan provides
for four systems to augment upwell i ng.These
four upwellin~systems will serve 48,240 square
feet (4341 m)of spawning habitat (Table
E.3.46).
As the ongoi ng studi es defi ne the habitat re-
quirements of the evaluation species,hydrology
of the sloughs and as flow regimes are refined,
it will be possible to detennine mitigation mea-
sures appropri ate to each of the sloughs.The
final selection and design of mitigation features
for each slough wll be derived in consultation
with NMFS,USFWS and ADF&G.
(v)Reduction of Impacts Over Time
A monitoring program will be conducted to eva1 uate
the effectiveness of mitigation measures (see Section
2.6)•
(vi)Compensat i on for Impacts
If the flow-related impacts cannot be minimized,
rectified,or adequately reduced with the implemented
E-3-166
-!
-
....
.....
2.4 -Mitigation Issues and Mitigating Measures
mitigation measures,it will be necessary to compen-
sate for the lost fi shery resources.The goal of
thi s compensation wi 11 be to produce the number of
fry expected to be lost from the impacted area.The
fi rst pri ori ty for compensating lost sal mon produc-
tivity will consist of channel modifications in side-
channels and mainstem areas to increase the suita-
bilityof these habitats for spawning.
The lack of suitable substrate may limit the avail-
ability of spawning habitat under project operation.
In areas with suitable hydraul ic conditions,the
addition of gravels or the cleansing of gravels in
areas with suitably sized particles will provide
additional habitat needed to accommodate adults
di spl aced from other habitats.Such projects have
been successfully undertaken in Washington (Gerke
1974;Wilson 1976;Washington Department of Fisheries
1981)and British Columbia (Lister et a1.1980).
Estimates of costs associated with these mitigations
are provided in Table E.3.39.
-Scarifying Side-Channels
Some of the existing side channels have substrates
suitably sized for spawning,but the particles are
cemented together by glacial silts and sands.The
heavy sediment load and peak flows that presently
exist in the Susitna River have resulted in a high
degree of compaction in the substrate.If the
sands and silts cementing the gravels together are
removed,it is expected these a reas wi 11 provi de
suitable spawning habitats.In some of these side
channels,a bulldozer with a scarifier will be
used,in combination with a high-flow release,to
rake the streambed,stir up the fine sediments
(Gerke 1974;Wilson 1976;Trihey 1982b;Kerr Wood
Leidal Association and D.B.Lister Association
.1980),and allow the fines to be carried away by
the streamf10w.This enhancement will be accom-
plished during reservoir filling.During filling
and operation,there will be a reduction of the
suspended sediment load and flood peaks (Chapter 2,
Section 3.3.2 and 3.3.3),which will be beneficial
in maintaining these 'areas after cleaning.The
mitigation plan provides for scarifying four side
channel s.The four scarified side channel swill
provide 120,060 square feet (lO,805 m2 )of spawn-
ing habitat (Table E.3.46).
E-3-l67
2.4 -Mitigation Issues and Mitigating Measures
-Slough Gravel Cleaning
In areas where the above technique will not work,a
mobile gravel cleaning machine will be used to re-
move sil ts and sands from the substrates.IIGravel
Gertie,1I developed by Washington State University,
may be suitable for use on slough and side-channel
substrate."Gravel Gertie"is a mobile gravel
cleaner that uses high-velocity water jets to flush
and then collect the silts from gravels for dispo-
sal (Mih 1980).Silts and sands removed from the
gravels will be discharged into the mainstem river
or di sposed of on 1and.Habitat improvement act i ...
vities on side channel s will be conducted in a
downstream sequence to reduce the chance of sedi-
mentation of fines from upstream sites impacting
downstream sites.Rehabilitation projects of this
nature have been successfully used for maintaining
chum salmon sloughs in Washington (Washington
Department of Fisheries 1981).It is anticipated
that all producti ve sloughs wi 11 need mai ntenance
cleaning on a 4-to 5-year cycle.The mitigation
plan provides for cleaning gravel in three sloughs
per year.
-Mainstem Spawning Beds
Under project operation,the peak flow events will
be significantly reduced in the reach from
Talkeetna to Devil Canyon (Chapter 2,Section
3.3.3[aJ).Some side channels and areas of the
mainstem will have suitable hydraulic conditions
for spawning under project operation,but the
streambed may not have substrate of appropri ate
particle size for spawning.In these areas,gravel
spawni ng beds wi 11 be added to create spawni ng
habitat (Figure E.3.30).Thus,gravels placed in
side channels and the mainstem to create suitable
spawning habitat will have a greater probability of
remaining stable under operational conditions.The
mitigation plan provides for construction of two
mai nstem spawni ng beds.These two beds wi 11 pro-
vide 120,015 square feet (10,800 m2 )of spawning
habitat (Table E.3.46).
Cleaning and supplementing spawning gravel cannot
be implemented until reservoir filling.Material
added to the mainstem and many of the side channels
prior to the control of flow would be quickly re-
distributed during pre-project summer floods.An
E-3-168
r""""
,....
.....
.-
.....
-
2.4 -Mitigation Issues and Mitigating Measures
analys is of candi date areas is bei ng conducted to
identify suitable sites.
-Chum Salmon Hatchery
A chum salmon hatchery facility will be constructed
if the previously described~higher priority~fish
mitigation alternatives cannot be successfully
impl emented.Ni ne potenti al chum sal mon hatchery
sites have been identified and evaluated within the
Susitna River basin based on water quality,indi-
genous fish species,access to electricity and
roads,soil characteristics,and land ownership
status of the respective sites (Kramer,Chin and
Mayo~Inc.1983).
A decision to implement hatchery production of sal-
mon within the Susitna basin would require defini-
tion of appropriate target species~management
goals,stock'selection~disease problems,and would
cause competition with native stocks •
(b)Mitigation of Downstream Impacts Associated
with Altered Water Temperature Regime
(i)Impact Issue
The creation of Watana and Devil Canyon reservoi rs
will change the downstream temperature regime of the
Sus itna Ri ver.Reservoi rs act as heat si nk.s ~reduc-
ing the annual variability and the rate of change in
water temperatures by moderat i ng summer and wi nter
temperatures and introducing a time lag.The magni-
tude of change in the thermal regime downstream de-
pends on the thermal stratification of the reservoir
and the design of the power intake and release struc-
t ures.
Some seasonal stratification is expected to occur in
Watana Reservoir (Fi gure E.2.106).Reservoi r thermal
model ing indicates that surface water temperatures
will reach 10°C (50°F)by August 1 and that the top
100 feet (30 m)of the water column will range be-
tween 8°to goC (44.4°to 48.2°F)(Chapter 2,Section
3.3.3(c)[i])•
The water temperatures downstream from the dam are
set in part by the elevation of the intake struc-
tures,which in turn determine the temperature of the
water drawn from the reservoir.Since growth rate in
E-3-169
2.4 -Mitigation Issues and Mitigating Measures
many aquatic organisms is temperature-dependent,
changes in the thermal regime can have profound
impacts on aquatic communities.Potential adverse
effects of higher winter temperatures include accele-
ration of incubation and early emergence of salmonid
embryos and benthi c invertebrates.The impact of
lower summer temperatures includes slower growth of
invertebrates,juvenile anadromous,and resident
fish.The lag effect may cause delayed spring spawn-
ing activity.Changes in the thermal character and
its effects will decrease downstream as tributaries
contribute to the flow and as the temperature regime
approaches an equilibrium state.The impacts related
to the thermal changes are expected to be confined to
the Talkeetna to Devil Canyon reach.
(ii)Measures to Avoid Impacts
The only mitigative alternative that would completely
avoid temperature changes downstream from the project
is no project alternative.Hydroelectric project
involving reservoir storage dams will alter the
natural temperature regime.
(i i"i)Measures to Mi nimi ze Impacts
The impacts associated with alteration of the temper-
ature regime during reservoir operation will be mini-
mi zed by i ncorporati ng mul ti pl e-l evel gates in the
power intake.Multiple level intakes have success-
fully regul ated temperature of downstream releases
(Nelson et ale 1978).
The success of temperature regulation depends on the
thermal structure of the reservoir and the location
of the intake ports.The reservoir operation model
was used in the design of the multilevel intake
structure.The cost of providi ng multi 1evel intake
structure for temperature control is provided in
Table E.3.39.
The summer pre-project temperatures range from 8°to
12°C (44.4°to 53.6°F)in the Devil Canyon to
Tal keetna reach.Temperatures near thi s range are
projected to exist in the top 100 feet (30 m)of the
reservoir (Chapter 2,Figure E.2.106).By accessing
this layer with the multiple-level intake,outlet
water temperatures will approximate existing baseline
water tempe ratures from the end of June to
mi d-Se ptember.
E-3-l70
2.4 -Mitigation Issues and Mitigating Measures
During the winter months,temperatures in the main-
stem are near DoC (32°F)in the Devil Canyon to
Talkeetna reach.Water temperatures 1°to 4°C (33.8°
to 39.2°F)are likely to occur in the Watana reser-
voir to a depth of 100 feet (30 cm),below which tem-
peratures will be a uniform 4°C (39.2°F)(Chapter 2,
Section 3.2.3[cJ).Surface water released at 4°C
(39.2°F)from Watana dam in early November are expec-
ted to reach DoC (32°F)by RM 103,while later in the
winter,surface water released at 2°C (35.6°F)from
Watana dam in early January are expected to cool to
near DoC (32°F)by RM 156,just above Devil Canyon.
(c)Mitigation of Inundation Impacts on
Mainstem and Tributary Habitats
(i)Impact Issue
In 1981,the arctic grayl ing popul ation in the im-
poundment area of both reservoirs,exclusive of
Watana Creek,was estimated to be approximately 9375
grayl ing greater than 8 inches (20 cm)(Tabl e
E.3.17),while in 1982 the total population was esti-
mated as at 1east 16,300 (ADF&G 1982e).Thi s pO/XIl a-
tion uses the clear-water tributaries as spawning and
rearing habitat and the tributaries and Susitna River
mainstem as overwintering habitat.A major project
impact will be the loss of grayling spawning and
rearing habitat in the inundated portion of the tri-
butaries.
(ii)Measures to Avoid Impacts
The only mitigation alternative that will avoid im-
poundment impacts for the proposed project is the no
project alternative.
(iii)Measures to Minimize Impacts
Mitigation measures that would substantially minimize
impoundment impacts to fish populations would be to
substantially lower the surface elevation of the
reservoi r or to mai ntai n su rface 1 evel duri ng the
embryo i ncubati on peri ode Neither measu re woul d be
feasible.
(iv)Measures to Rectify Impacts
Since the impoundment is essentially a permanent
impact,rectification measures are not feasible.
E-3-171
2.4 -Mitigation Issues and Mitigating Measures
Rectifying measures,such as providing replacement
grayling spawning habitat within the impoundment are
not considered feasible because of the timing and
magnitude of the drawdown cycle.
(v)Reduction of Impacts
Impacts cannot be reduced over time since no effec-
tive mitigation measures have been identified.
(vi)Compensation for Impacts
A propagation program will be initiated to compensate
for the loss of these grayling.In order to compen-
sate for the loss of grayling,in-kind,in-basin
replacement is planned.Compensation for loss of
aquatic habitats in the two reservoirs will be ac-
complished by:
-Funding research on grayling propagation tech-
nol ogy;
-Hatchery propagation of grayling or other resident
species and subsequent planting of the reared fish;
-Introduction of rainbow trout into the Devil Canyon
reservoi r.
Estimated costs of these mitigations are provided in
Table E.3.39.
-Grayling Propagation Technology
Artificial propagation of arctic gray1 ing using
existing techniques is not expected to produce the
number of adults or adult-equivalents needed to
compensate for the expected losses.At present,
grayling propagation in Alaska consists of strip-
ping eggs from wild adults,incubating the embryos
until hatching,then releasing the newly hatched
larvae.This technique is limited by the avail-
ability of gravid wild adults,substantial larval
mortality,and no satisfactory way of measuring
success.If the larvae are artificially reared for
two to three months until they are past the larval
stage,the early mortal ity can be substantially
reduced.Grayl ing of this size,approximately 1.4
to 2 in.(3.5 to 5 cm),can be marked so that the
success of the program can be evaluated.
E-3-l72
r
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,...,
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F"'",
2.4 -Mitigation Issues and Mitigating Measures
Prior to construction of Watana dam,the project
will fund research on the rearing of grayling
larvae so that the technology will be available
when the compensating grayling are needed.This
research will also provide the ADF&G with an addi-
tional fisheries management tool.The research
program cou1 d be conducted under the auspi ces of
ADF&G at an existing hatchery facility and financed
by the project.
-Hatchery Propagation of Grayling
or Other Resident Species
After the demonstration of a successful technology
for gray1 ing rearing,a gray1 i ng hatchery program
will be undertaken either by expansion of an exist-
ing facility or construction of a new facility.A
drawing for a grayling hatching and rearing facil-
ity is shown ·in Figure E.3.31.
Hatchery produced grayling will be planted in lakes
in the proj ect area.The number of gray1 i ng to be
planted and number of lakes to receive grayling
will be determined based on the carryi ng capacity
of the selected lakes.Sufficient grayling will be
planted so that the number of catchable grayling
will be similar to that number lost.If suitable
habitat does not exist in the vicinity of the im-
poundment to support the number of lost grayling,
suitab1 e areas outsi de the project area will be
selected for stocking grayling.The lakes to be
stocked will be selected in consultation with
ADF&G,USFWS,BlM,and adjacent land owners.
Preference will be given to areas near the project
area that currently support high levels of harvest
pressu reo
If the grayling rearing program is not technically
feasible or if appropriate planting areas do not
exist,the alternative compensation is to provide
artificially reared rainbow trout.The technology
of rearing rainbow trout is well established and
there is a high demand for the species.An exist-
ing facility would be expanded and the trout made
available for stocking outside the project area in
consultation with ADF&G,USFWS and BlM.Costs will
be simil ar to those estimated for the gray1 i ng
propagation program.
E-3-173
2.4 -Mitigation Issues and Mitigating Measures
-Introduction of Rainbow Trout
into Devil Canyon Reservoir
The Devil Canyon reservoir,unlike the Watana res-
ervoir,is expected to contain habitats favorable
for fish production.The Devil Canyon reservoir
contains several tributaries that will support
rainbow trout spawning,primarily Tsusena Creek and
Fog Creek,but also Cheechako Creek and several
unnamed tributaries.At present,the natural range
of rainbow trout ends at Devil Canyon,where up-
stream movements are blocked.
It is expected that rainbow trout will make full
use of reservoir habitats by spawning and rearing
in clear-water tributaries and rearing and over-
wintering in the reservoir.Rainbow trout to be
planted in the reservoi r wi 11 be acqu i red from
exi st i ng facil it i es wi thi n the state.A stocki ng
program will be established in consultation with
ADF&G.
(d)Mitigation of Downstream Impacts
Associated with Nitrogen Supersaturation
(i)Impact Issue
Nitrogen supersaturation in outflow waters has caused
significant fish mortalities from gas bubble disease.
Water passing over a high spillway into a deep plunge
pool entrains air.Nitrogen passes into solution at
depth and a state of supersaturation exists when the
water returns to the surface causing persaturation.
The degree to which this occurs depends on the depth
of the plunge pool,height of the spillway,amount of
water bei ng spi 11 ed,and downstream tu rbu 1ence.
Supersaturated water is unstable and eventually will
return to equilibrium levels if exposed to the air.
However,travel time downstream during high flow
periods can be fairly short,causing supersaturation
to extend considerable distances downstream.
(ii)Measures to Avoid Impacts
Gas supersaturation will be avoided by including
fixed-cone valves in the outlet facilities.These
valves,in combination with the powerhouse flows,
will discharge all flood flows up to the 1:50-year
flood without causing supersaturation.A prototype
test of cone val ves showed them to be effecti ve in
E-3-l74
-
2.4 -Mitigation Issues and Mitigating Measures
p reventi ng gas supersaturat ion (Ecological Analysi s
Inc.1982).Costs associated with providing the gas
supersaturation control structures are provided in
Table E.3.39.
(i i i)Measures to Mi nimize Impacts
The likelihood of creating gas supersaturation down-
stream from the dam wi 11 be reduced by mi nimi zi ng
release through reservoir management.Releases occur
when the reservoi r is full and i nfl ow exceeds out-
flow.By holding the reservoir below full pool for
most of the year,flood control capacity would be
increased,thus decreasing the probability of spills.
The reservoir must reach maximum storage level by
September 30 to meet winter power demands.Storms do
occur in the Susitna drainage that may require re-
lease of water;however,the structures and operation
criteria have been designed to minimize releases and
spills.
2.4.5 -Cumulative Effectiveness of Mitigations
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I
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(a)Construction Mitigation
Through siting and designing of project facilities,appro-
priate construction practices,and careful scheduling activ-
ities as discussed in Section 2.4.3,it will be possible to
minimize adverse impacts to aquatic habitats resulting from
project construction:The i ndi rect impacts caused by
increased access to harvestable fish populations will be
reduced during construction by providing workers with alter-
nating recreational opportunities,by instituting a catch-
and-release policy for project workers,and by supporting
such harvest regulations as the Board of Fisheries imposes.
It is expected that impacts will not be avoided and that
increased access will have long-tenn impacts on fish popula-
tions cau~ed by the increased harvest pressure.
Aquatic habitat will be ,altered by removing gravel from the
floodplain.These impacts will be rectified by rehabilita-
tion practices discussed in Section 2.4.3.
Fuel spills and road runoff will decrease water quality in
streams downhi 11 from project roaQs.These impacts wi 11
be reduced by having a properly t rained and equi pped spill
response team at the construction site.
£-3-175
2.4 -Mitigation Issues and Mitigating Measures
The construction monitoring team will identify areas where
remedial actions such as repair,realignment,or redesign
are needed.
(b)Operation Mitigation
(i)Mitigations of Access and Impoundment Impacts
The primary program design is to mitigate residual
impacts of the access road and reservoir and to com-
pensate for these losses by artificially propagating
grayling and introducing these grayling into suitable
project and non-project area waters.As part of this
compensation,research on grayling propogation will
be funded to increase fi s hery management opti ons.
The target number of grayling to be produced will be
equiv.alent to the number lost in the impoundment.
The target number of grayling to be produced will be
equivalent to the number lost in the impoundment.
The primary areas considered for planting are
project-area 1akes that are capabl e of supporting
grayling.If grayling propagation proves not feas-
ible,rainbow trout will be substituted for planting
outside the project area.
Where feasible,access will be provided to the
stocked areas to divert harvest pressure from adja-
cent natural populations.Additional artificially
produced grayling can be introduced into project-area
streams if natural popul ati ons become depl eted and
population enhancement is deemed to be desirable by
the ADF&G.If the carrying capacity of project-area
enhancement sites is exceeded by the number of gray-
ling available,the excess grayling will be made
available for planting outside the project area.
Final decisions on the distribution of residual gray-
ling will be made in consultation with ADF&G,USFWS,
BLM,and adjacent landowners.
Road access to the project area wi 11 resul tin i n-
creased resource use.Angling pressure would be con-
trolled by the Board of Fisheries through harvest
regul ati on i ncl udi ng catch 1 imits,restri ct i ve cap-
ture techniques (e.g.,fly fishing only and single
hook),and adjustments in the open season.
E-3-176
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2.4 -Mitigation Issues and Mitigating Measures
..-
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(i i )Mitigation for Downstream Impacts
The goal of the downstream mitigation program is to
provide adequate habitat downstream from Devil Canyon
Dam that will minimize adverse impacts on fish
resources.It is anticipated that the mitigation
program will fully mai ntai n,and probably enhance,
salmon productivity in the Devil Canyon to Talkeetna
reach.During the development of the mitigation pro-
gram,volumetric,temporal,physical,and chemical
needs of the anadromous fish resources between Devil
Canyon and Talkeetna were eva1 uated.Studi es and
modeling of the inter-relationships of these para-
meters will continue to refine and quantify the miti-
gation program.
Several project featlJres have been incorporated into
the desi.g.n to avoid or reduce impacts.Fixed-cone
valves will be installed in the outlet facilities to
prevent gas supersaturation.The multiple-level
power intake gates will allow water to be withdrawn
from the upper 1eve1 s of the water col umn over the
full drawdown range.This abil ity to withdraw water
from the upper levels will allow control over down-
stream temperatures during periods of stratification.
The project operational flows were developed with an
intent to provide a maximum flow during the summer
that would not substantially affect the project
economics or energy production capabil iti es.These
operational flows will alter the physical charac-
teristics of the sloughs,thereby reducing ease of
access and available spawning area for adult salmon
and i ncreasi ng embryo mortal ity if the sloughs de-
water or freeze after spawning is completed.Fry
that survive may not leave the sloughs if the migra-
tion stimu1 us,possibly a combination of a proper
temperature and flow pattern,is eliminated.
The project operational flows will allow downstream
impacts to be minimized when used in conjunction with
proposed rectifying and compensating measures.The
primary rectifying measure is to use stream enhance-
ment techniques to modify natural slough habitats to
mai ntai n natural sal mon spawni ng and fry production.
The slough enhancement process is composed of a
series of steps to rectify the loss of natural slough
habitat.These steps may be used singly or in combi-
nation in any particular area,depending on the con-
troll i ng factors in an affected slough.These steps
are:
E-3-177
2.4 -Mitigation Issues and Mitigating Measures
-Providing an upstream berm that will prevent the
river from entering the enhanced slough during
winter staging.This control maintains the in-
tegrity of the spawning gravels and reduces thermal
impacts.
-Selecting a slough that retains ground water flow
with suitable thermal characteristics under opera-
tional flow levels.The selection process is eval-
uating a number of criteria to assess the potential
for the slough to maintain sufficient ground water
flow under operational flows to maintain salmon
embryos through the winter and allow properly timed
development.Emphasis will be on sloughs that are
currently most productive.
-Providing adult salmon with access into the slough
by enhanci ng the backwater effect at the slough
mouth and lowering the slough profile.
-If ground water flow cannot be naturally maintai~ed
by lowering the slough profile,areas where the
ground water flow can be artificially maintained
will be considered.
The extent and type of habitat enhancement depends on
natural site characteristics,such as ground water
f1 ow rates,size of natural features,and factors
that appear to 1 imit salmon productivi ty in each
slough.The number of sloughs modified will depend
on the desired level of production.It is the Power
Authority's intent to maintain production at histori-
cal locations and levels.
In addition to slough modification,mainstem spawning
beds will be provided as a compensation measure.
Additional mainstem and side channel spawning areas
will be provided by scarifying or cleaning compacted
gravel s.
The proposed rectifying and compensating actions will
provide an estimated 432,315 square feet
(38,902 m2 )of spawning habitat (Table E.3.46~.
This total is over 187,000 square feet (16,830 m )
greater than the maximum estimated spawning habitat
required by salmon spawning in sloughs upstream from
Tal keetna in 1981 and 1982.It is expected that
these mitigation features will allow salmon popula-
tions in the Devil Canyon to Talkeetna reach to in-
crease over historical levels.
E-3-178
(C""-
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2.5 -Aquatic Studies Program
The aquatic studies program is an integral part of the continuing plan-
ning and design for the Susitna Hydroelectric Project.The information
presented in this document is primarily based on results of 1981 field
stud i es with some prel imi nary i nformat i on from the 1982 study program.
Interpretation and analysis of the 1982 data are in progress and sup-
plemental reports containing the results of these analyses will be com-
pleted in June 1983.Continuing field data collections have been
funded through the 1982-1983 winter season.Modeling efforts have been
initiated to incorporate all project data into a quantified impact
assessment.Scopes of work for the 1984 fiel d season are being de-
veloped.As additional information becomes available from field
studies and impact analysis~the mitigation plan will be refined and
detailed plans specifying number~location~and design of mitigation
features will be prepared.The Power Authority will provide details of
these studies and plans as they become available.
As a more refined understanding of project impacts and viable mitiga-
tion features is acquired,the emphasis of the study program will shift
towards providing the design criteria needed to implement the mitiga-
tion features.The aquatic studies will produce the information
requi red to prepa re mit i gat i on programs for the preconstruct ion,con-
struction,filling,and operational phases of the project and phases
into a long-term monitoring program.
2.5.1 -Preconstruction Phase
Duri ng the preconstructi on phase,the aquatic studi es program
wi 11 :
-Provide supplemental information required for support of the
license application;
-Continue to define seasonal habitat relationships;
-Continue quantifying the predicted impacts;and
-Refine the proposed mitigating measures ..
The need for specific tasks will be transl ated into fi el d pro-
grams.
2.5.2 -Construction Phase
During the planning for construction,information will be needed
to properly design site facilities and schedule construction
activities to avoid impacts to aquat~c habitats.Incorporating
environmental design criteria into design~siting~and scheduling
activities is a major feature of the construction mitigation
plan.Review of proposed actions and fadl ities will generate
E-3-179
2.6 -Monitoring Studies
the need for some additional data.These needs will be transla-
ted into an orderly field study program.Environmental design
criteria will be incorporated during the plannin9 stage in order
to avoid or minimize impacts.
2.5.3 -Filling and Operation Phases
During filling and operation,monitoring studies,as discussed
below,will permit refinement of mitigation features to improve
performance.
2.6 -Monitoring Studies
As discussed in Section 1.3 and the Susitna Hydroelectric Project Miti-
gation Policy Report,monitoring studies are recognized as an essential
project mitigation feature that provides for a reduction of impacts
ove r time.Mani tori ng wi 11 be conducted du ri ng project construction
and operation:
-To insure that good construction practices are being employed on the
project;
-To evaluate the effectiveness of the operation and maintenance of
mitigation features;and
-To recommend changes in construction practices or mitigation features
to further avoid,minimize,or reduce impacts.
An interagency mitigation monitoring team will be established to ensure
the proper and successful execution of the mitigation plan and to
determine its effectiveness.The organization and operation of a
monitori ng team will be determi ned through di scussi ons with resource
agencies leading to a memorandum of understanding.
2.6.1 -Construction Monitoring
Construction monitoring will consist of monitoring construction
activities to ensure that proper construction practices,as
detailed in the project construction practices manual,are being
followed and that project facilities are being properly main-
tained.This monitoring activity will cover all project facili-
ti es,i ncl udi ng access road construct i on and ma i ntenance,camp
and village construction,material removal,washing operations
for dam construction,reservoir clearing,abandonment,and reha-
bilitation activities.
E-3-l80
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2.6 -Monitoring Studies
As outlined in the project schedule,construction of the main
access road will begin in January 1985.From that time,until
construction of the project is complete,a team of construction
monitors wi 11 be present at the project site.On a daily bas is,
the monitoring team will visit areas where construction is
occurring.Their primary responsibility will be to provide
guidance on permit compliance relative to daily activities.
Prior to constructing facilities,the environmental team will
review the final designs and means of construction with regard to
permits,license stipulations,and design and construction cri-
teria manual s.This will ensure conformance to approved prac-
tices.Once construction has begun,onsite changes in permit
stipulations may be required because of changes in construction
techniques or accidents.If a variance is required,a represen-
tative from the regulatory agencies who will be present onsite,
will have the authority to authorize field actions that were not
specified in the permits.After facilities or portions of facil-
ities have been constructed,the monitoring team will review the
designs and verify that the facility is in compliance with permit
and license stipulations.
Throughout the construction period,the implementation and execu-
tion of the monitoring program will be the responsibil ity of the
Power Authority but daily management will be delegated to the
design manager.The construction monitoring teams in the field
will report on a regular basis to the design manager.The
design manager,in turn,will be responsible for relaying appro-
priate information to the Power Authority.If a variance is
requested by construction crews in the field,the construction
and design managers as well as the Power Authority will be noti-
fied.
The construction monitoring crew will determi ne compl iance with
permit or license stipulations.If a facility or activity is
found not to be in compliance with existing stipulations and if a
variance was not requested prior to implementing the acitivity,a
certificate of non-compliance will be issued and all responsible
parties will be notified.
The construction schedule and proximity of activities will dic-
tate the size and number of monitoring teams.Early in the con-
struction phase (1985-1988),the monitoring team will be small,
since activities will be limited to construction of the access
road and to the Watana dam site.Beginning in 1989 and extending
through 1991,the construction of the Anchorage to Fairbanks
transmission line will necessitate a larger crew operating over a
much larger area.By 1994,the transmission line and Watana dam
will be complete;however,construction of site facilities at
E-3-l81
2.6 -Monitoring Studies
Devil Canyon will just be starting.During this interim period,
the number of monitoring teams and the extent of their coverage
will be reduced.The construction of the main dam at Devil
Canyon in 1996 will result in only a small increase in the size
of the monitoring team,since most activities will be limited to
the damsite and the access road.As indicated by the current
schedule,construction activities,including the monitoring
program,will end in 2002.
2.6.2 -Operational Monitoring
Operational monitoring will be conducted to (1)monitor salmon
population and production levels to ensure that the predicted
level of impact is not bei ng exceeded,and (2)eval uate the
effectiveness of the project mitigation plan.Costs associated
with the operational monitoring are provided in Table E.3.47.
(a)Impact Monitoring of Salmon Populations
Salmon populations in the Devil Canyon to Talkeetna reach
will be monitored to determine if populations maintain his-
torical levels during the operation phase.Monitoring will
consist of enumerating returning adults that pass Sunshine
and Curry Stations and monitoring smolt out-migration from
the reach.Adults will be enumerated using the fishwheel
and tag/recapture program currently being used in the base-
line studies.The smolt out-migration will be evaluated
usi ng a smol t trap program such as was conducted in the
Spring 1982 study program.
The results of these studi es will be used to eval uate
changes in the population size,species composition or
changes in stream use patterns of the fi ve Pacifi c salmon
species.Results of the mitigation monitoring described in
Section 2.6.2 (b)will be used to determine the cause of
changes.
(b)Mitigation Monitoring
Mitigation features to be monitored to evaluate whether any
adequate level of mitigation is being achieved include:
-Sloughs;
Mainstem and side channel salmon spawning areas;
-The resident fisb population provided by the stocking pro-
gram;and
-The fixed-cpne valves designed to avoid gas supersatura-
tion.
E-3-182
-
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2.6 -Monitoring Studies
The monitoring activity will include evaluating the opera-
tion and maintenance procedures to ensure that the facili-
ties are operating effectively.
If it is determined that a mitigation feature is not meeting
the intended 1 evel of effecti veness s modificati ons to the
migitation feature will be made to further reduce impacts.
The specific modifications will be made on a site-specific
basis in consultation with the monitoring team.
(i)Monitoring Slough Modifications
The various features incorporated for slough habitat
enhancement wi 11 be monitored to determi ne whether
they are meeting their intended function and are
operating properly.
Miti gati on features desi gned to all ow adul t sal mon
access into the sloughs will be annually inspected
after breakup to identify and effect any needed
repairs prior to the adult return.Annual monitoring
of returning adults will identify access problems or
passage delays and appropriate corrective actions as
recommended by the monitoring team will be taken.
Modifications to sloughs designed to maintain spawn-
i ng areas will be annually inspected pri 0 r to the
spawni ng season to verify that the area conta i ns
suitable spawning conditions such as amount of flows
depth of waters and suitable substrate.Areas that
become overly silted will be cleaned.If flows
diminish so that spawning is no longer possibles the
monitoring team will recommend appropriate corrective
act ion.
The number of spawning adults returning to the
sloughs will be monitored annually to measure changes
in run size to determine if the combination of mini-
mum flow and slough modifications is maintaining
natural production.This monitoring will also serve
to determi ne whether the capacity of the modifi ed
areas is ·being exceeded.Appropriate remedial
actions s as recommended by the monitoring teams will
be taken when spawning damsites are either too low or
too hi gh.
Fry production wi 11 be monitored annually to verify
incubation success.Fry monitoring will include an
assessment of out-migration timing and success.
E-3-183
2.6 -Monitoring Studies
The annual slough monitoring will include an evalua-
tion of general slough conditions including vegeta-
tive encroachment,beaver occupations and general
condition of the spawning and rearing areas.Appro-
priate remedial actions recommended by the monitoring
team will be performed to maintain slough productiv-
ity.
Following flow regulations representative sloughs
wi 11 be instrumented with temperature and flow
recordi ng instruments to monitor physi cal character-
istics of the sloughs throughout the year.Monitor-
ing of the physical processes will be continued until
slough conditions stabilize under the regulated flow
regime.This physical processes monitoring will be
used in part to determine whether further modifica-
tions to the physical habitat must be made to main-
tain slough productivity.
Methods used to evaluate the slough mitigation fea-
tures will be consistent with methods currently being
used to assess baseline conditions of the parameters
to be monitored.Specifi c study programs wi 11 be
eval uated and approved by the monitori ng team pri or
to implementation.
(ii)Monitoring of Mainstem and
Side-Channel Spawning Areas
The mainstem and side channel spawning areas that are
provided as mitigation features will be monitored to
quantify adult salmon use of these areas.If the
areas recei ve the expected level of use s the beds
will be monitored and maintained on an annual basis.
Monitoring methodology will be similar to that cur-
rently used to evaluate mainstem and side-channel
spawning habitats and will include standard physical
and chemical measurements as well as biological
ana lyses.
(iii)Monitoring of Stocked Grayling
and Other Resident Fish
Areas that a re stocked wi th grayl i ng or other res i-
dent fish to compensate for impoundment losses will
be monitored to ensure that the stocking program is
providing a,repl acement popul ation of harvestabl e
E-3-184
2.7 -Cost of Mitigation
,....
....
....
(i v)
fish.The monitoring program will include evalua-
tions of abundance,growth and age structure.
Restockings will be made as needed.If the initially
stocked areas will not support the desired pOj)..lla-
tions,additional habitats will be evaluated for
stocking •
Monitoring of Fixed-Cone Valves
The performance of fixed-cone val ves will be evalu-
ated to determine whether gas supersaturation is
being avoided.This monitoring will consist of a
one-time evaluation of gas supersaturation during a
release-to verify that the valves are operating as
designed.
....
2.7 -Cost of Mitigation
To develop estimates of mitigatinn cost,1982 cost estimates were pre-
pared for each activity (Tables E3.39,E3.41,E3.45 and E3.47).These
cost estimates were based upon u nit cost i nformat i on deri ved from
recent experience in Alaska or upon experience elsewhere and/or
earl ier,and escalated to arrive at 1982 cost estimates for south-
central Alaska.Costs for the mitigation program were separated into
construction cost and average annual operating cost.For the major
mitigation activities,these costs are:
Construction Cost
Downstream Mitigation (Table E.3.39)
Impoundment Mitigation (Table E.3.39)
Dam Structure (Table E.3.39)
Water &Fisheries Quality Monitoring
(Table E.3.41)
Aquatic Studies Program (Table E.3.45)
Total Construction Cost
Average Annual Operating Costs
Fisheries Monitoring (Table E.3.47)
Maintenance of Facilities (Table E.3.45)
Total Average Annual Operating Cost
$6,380,000
1,315,000
80,100,000
12,165,100
6,000,000
$105,960,100
$511,400
1,064,000
$1,575,400
These costs do not include any contingency costs or owner's administra-
tive costs.
E-3-185
2.8 -Agency Consultation on Fisheries Mitigation Measures
Three agencies,USFWS,ADF&G,and Alaska Department of Natural Resour-
ces provided comments on fisheries mitigation measures.
2.8.1.-U.S.Fish and Wildlife Service
The USFWS provided formal comments on fisheries
sures on October 5,1982,and January 14,1983.
ments are divided into construction-related
operation-related mitigations.
(a)Construction Mitigations
mitigation mea-
The USFWS com-
mitigations and
F'""'""-'
Construction mitigations primarily concern siting,design,
and scheduling.The comments are:
-Siting and Design
The access road and transmission 1 ine between Watana and'
Devil Canyon should use the same corridor.
The diversion tunnel should be screened to avoid entrain-
ing fish.The siting of construction and permanent vil-
1 ages and other facil it i es shoul d be revi ewed with the
goal of minimizing impacts.
-Schedul i n~
Construction activities and reservoir clearing should
occur in the winter to minimize impacts.Work in aquatic
systems should be scheduled to avoid conflicts with sensi-
tive life history stages.
All of these comments have been addressed in Section 2.4.3.
A design criteria manual and a construction practices manual
are being prepared for the project that will detail the sit-
ing,design,and construction practices criteria that wil1
be used on the project.These manual s wi 11 be prepared in
consultation with the agencies.The manuals will include
timing and scheduling based on the identified sensitive
periods and the needs of the construction contractor.
(b)Operation Mitigations
Comments on operation mitigations were divided into those
concerning reservoir mitigations and downstream mitigations.
(i)Reservoir Mitigations
Recommendation:
ties need to be
options include
extens i on of
access.
Within and out-of-basi n opportuni-
examined to offset losses.Possible
stream stocking,lake fertilization,
existing fisheries and increased
E-3-186
--
-
-
-
2.8 -Agency Consultation on Fisheries Mitigation Measures
Response:The mitigation plan provides for a gray-
ling hatchery and planting program that will intro-
duce grayling into waters in,or in the vicinity of,
the project to compensate for lost grayl ing habitat
in the reservoirs.The waters to be stocked will be
selected based on a review of water bodies in and
near the project area,in consultation with USFWS,
ADF&G,BLM,and adjacent land owners.
The project facilities and recreation plan will pro-
mote increased access and extension of existing
fi sheri es.
Recommendation:The viability of a reservoir fishery
needs to be evaluated.
Response:The Watana and Devil Canyon reservoirs
were evaluated in terms·of their suitability as fish
habitat.It was concluded that the drawdown cycle in
the Watana reservoir will limit fish populations and
wi 11 probably not support a qual ity reservoi r fi sh-
ery.A grayling fishery,however,would develop in,
and at the mouths of,tri butaries di schargi ng into
the reservoir.For the Devil Canyon reservoir,it
was concluded that a re.servoir fishery is a viable
opti on because of the timi ng and magnitude of draw-
down cycle.The mitigation plans provide for intro-
ducing rainbow trout into the Devil Canyon reservoir,
since this species is expected to utilize both reser-
voir and tributary habitats.This introduction would
extend the range of ra i nbow trout past Devi 1 Canyon,
but the species would be precluded from entering the
upper basin by Watana dam.
-
(i i )Downstream Mitigations
Recommendation:Mitigation options for the dewatered
area between the Devil Canyon dam and its powerhouse
need to be considered.
Response:The habitat lost between Devi 1 Canyon dam
and the powerhouse is typified by velocities between
9 and 16 ftjsec (2.iand 4.8 mjsec),the substrate is
bedrock.The area is not expected to provide signi-
ficant fish habitat,thus the dewatering of the sec-
tion is not expected to result in substantial im-
pacts.The few chinook that migrate through the
canyon during low water years (such as 1982)wil,l be
blocked by the dam.Milling areas will still be
available at the powerhouse outlet.Because of these
factors,mitigation measures are not proposed.
E-3-187
2.8 -Agency Consultation on Fisheries Mitigation Measures
Recommendation:The potential to establ ish/expand
the salmon fishery between the Devil Canyon and
Watana damsites,in the absence of a Devil Canyon
dam,needs to be addressed.
Response:The flows downstream from Watana Dam are
expected to permit chinook salmon to ascend to
Tsusena Creek,at the base of the dam.If the Devil
Ca nyon dam is eventu ally eli mi nated from the planned
development,it would be possible to establish a
fishery in this reach.Since Devil Canyon dam is a
part of the present pl an,devel opi ng these chi nook
stocks for the period between Watana development and
Devil Canyon development is not considered cost-
effective mitigation.
Recommendat ion:Adju stments to the Watana reservoi r
filling schedule to m"inimize impacts to fish resour-
ces should be considered.Addition of a low-level
intake port should be evaluated.
Response:Lengthening the filling period would delay
impacts to grayling but would not reduce these im-
pacts.Lengtheni ng the fi 11 i ng peri od wou 1d i n-
crease downstream impacts to salmon by increasing the
number of years that returning adults are exposed to
lower temperatu res du ri ng the u pst ream mi grat ion.
Shorteni ng the f"j 11 i ng peri od may el imi nate the tem-
perature impact,but would increase impacts caused by
low flows.It may be possible to achieve a balance
of low flows combined with short-term augmented flows
during the second filling year that would minimize
temperatu re/fl ow impacts and fi 11 the reservoi r on
schedu 1e.These opt ions are bei ng evaluated along
with the desirability of a low-level intake port.
Reconunendation:An expanded discussion of the salmon
hatchery mitigation option should be provided.
Response:The salmon hatchery mitigation option is a
low priority compensation alternative.It is antici-
pated that the proposed mitigation will maintain
salmon po~lations in the historical locations and
that a hatchery will not be needed.Nevertheless,a
hatchery siti ng study has been compl eted (Kramer,
Chin and Mayo,Inc.1983).
Reconunendation:Slough modifications to increase
fish habitat need to be demonstrated.
E-3-l88
-
-
"""
-
-
....
2.8 -Agency Consultation on Fisheries Mitigation Measures
Response:Investigations into the maintenance of
salmon spawning habitat in sloughs is continuing as
part of the design studies.
2.8.2 -Alaska Department of Fish and Game
The Alaska Department of Fish and Game (ADF&G)provided comments
on mitigation measures on July 27,1982 and January 13,1983.
The ADF&G comments related to mitigation of lost grayling habitat
and mitigation for alterations to downstream salmon habitat.
Recommendaton:Hatchery propagation of grayling in Alaska is not
well developed at present and grayling production in Alaska must
be considered experimental.
Response:It is recognized that grayling propagation is not well
developed.The mitigation plan provides for a three-year experi-
mental phase to develop grayling propagation technology that will
have utilization beyond project needs.Since ADF&G intends to
develop grayl i ng propagati on techni ques and the Power Authority
has a need for such technology,a cooperative experimental effort
would be desirable.
Recommendat ion:Instream flows and temperatures requi red to
maintain present populations should be carefully eval uated to
provide a basis for further migration measures.
Response:The ongoing studies are addressing these concerns and
substantial analysis will be available on June 30,1983.These
will be further analyzed during refinement of the mitigation
pl an.
Recommendation:If onsite mitigation of fisheries impacts cannot
be accomplished,hatcheries should be considered.
Response:The salmon hatchery option is a low priority compensa-
tion alternative.It is anticipated that onsite mitigation will
be effective at maintaining production of slough and mainstem
spawni ng sal mono Neverthel ess,a hatchery sit i ng study has been
completed (Kramer,Chin and Mayo,Inc.1983).
Recommendation:Results from the ADF&G study on the salmon en-
hancement potential of the upper Susitna River without the pro-
ject should be included in the discussion of mitigation options.
Response:The study had not been received by the time this
document went to press •
E-3-189
2.8 -Agency Consultation on Fisheries Mitigation Measures
2.8.3 -Alaska Department of Natural Resources
The Alaska Department of Natural Resources'comments of January
13,1983,requested that downstream mitigation,other than slough
modifications,be included.The discussion of downstream
mitigation has been substantially revised to indicate more
clearly that a series of habitat enhancement techniques will be
undertaken,rather than construction of an artificial spawning
channel.Al so,enhancement of mai nstem spawni ng habitats wi 11
provide new habitat in previously unutilized areas.
E-3-190
.....
-I
-
-
3 -BOTANICAL RESOURCES
3.1 -Introduction
The object of this report is to describe the existing botanical
resou rces of the Su sitna Basi n;the impacts whi ch the Su sitna Hydro-
electric Project will produce on those resources;and mitigative
measures incorporated by the project to avoid,minimize,rectify,
reduce,or compensate for the predicted adverse impacts.As stated in
Section 1.2,the primary importance of botanical resources within the
project area is their key role as components of wildl ife habitat.The
following discussions have been coordinated closely with baseline
descriptions,impact assessments,and mitigative measures presented in
Section 4 (Wildlife),and form an important basis for that section.
A diversity of plant cOl11ll1.lnities occurs within the study area desig-
nated for botanical resources and wildlife of the Susitna Hydroelectric
Project.The study area (Figures E.3.32 through E.3.35)includes the
watershed of the Susitna River upstream from Gold Creek;a corridor
extending approximately 1 mile (1.6 km)to each side of the downstream
floodplain between Gold Creek and Cook Inlet;corridors approximately 5
miles (8 km)in width encompassing the transmission routes from Healy
to Fairbanks and ..Willow to Anchorage;and the intertie transmission
corridor from Willow to Healy,with a study area varying from approxi-
mately 4 to 18 miles (6.4 to 28.8 km)in width (Conmonwealth Assoc.
1982).
In this report,the entire Susitna Basin has been subdivided into three
component drainage basins:the upper,middle,and lower basins.These
areas are delineated in Figure E.3.3,and the designations are used
consi stently throughout the di scussi ons of botanical resou rces and
wildlife (Exhibit E,Chapter 3,Sections 3 and 4,respectively).
However,because the watershed of the Susitna River upstream from Gold
Creek,at River Milepost (RM)136.8 (Figure E.3.33),was distinguished
for study pu rposes from the downstream fl oodpl ai n .study corridor
(Figure E.3.34),data were evaluated separately for these two areas in
certain cases.In these cases,the entire basin area upstream from
Gold Creek is defined as the Watana and Gold Creek watersheds,as shown
in Figure E.3.36.Data presented collectively for the Watana and Gold
Creek watersheds therefore include all of the upper basin and all of
the middle basin except that portion downstream from Gold Creek.The
latter area is represented in the downstream floodplain study
corridor.
Unless cited otherwise,the descriptions that follow are from
McKendri ck et a1.(1982).Vegetati on types are characteri zed in accor-
dance with the terminology of Viereck and Dyrness (1980).Conmon names
of plant species appear in the text;their scientific names are shown
in Appendix ED.Species and varieties under--review by the USFWS for
official designation as endangered or threatened are referred to by
scientific nomenclature in the text.
E-3-191
3 -BOTANICAL RESOURCES
3.1.1 -Regional Botanical Setting
The Su sitna Ri ver system drai ns parts of the Al aska Range to the
north and parts of the Ta"'keetna Mountains to the south.The
vegetation communities of the region are typical of those cover-
i ng vast areas of Al aska and northern Canada.They include
forest and shrub communities on stream floodplains;coniferous
and deciduous forests on canyon slopes adjacent to the flood-
plains;shrub communities,conifer stands,and tundra on benches
above the canyon slopes;and tundra at higher elevations (Figure
[,3.38).River action and fires contribute greatly to the
ever-changing mosaic of plant communities and successional stages
within the region.
Predominant vegetation of the lower mountains and lower slopes of
the higher mountains in the project area is alpine tundra as
classified by Viereck and Dyrness (1980).Some areas mapped as
rock have pioneering species growing in crevices,but the plants
provide negligible ground cover.These habitats are common in
mou nta"j nou s areas throughout Al aska.Permanent snowfi el ds and
glaciers are found at higher elevations of the Susitna watershed
in the Alaska Range.
The benches bordering the middle basin portion of the Susitna
River and the area arou nd the Maclaren Ri ver are moi st tu ndra.
This type includes herbaceous meadows as well as shrub-dominated
sites,both of which are widespread in Alaska,especially in
the Brooks Range,on the Seward Peninsula,and near the Killuck
Mou nta ins.
Along east-west reaches of the Susitna River in the middle basin,
steep canyon slopes and some adjacent areas are covered with
closed spruce-hardwood forest (Vi ereck and Dyrness 1980).Thi s
type of vegetation is most common along ri vers in the
south-central and interior regions of Alaska.
Vegetation north of the Susitna River to the Denali Highway
along portions of the Seattle,Brushkana,and Deadman Creek
drainages is variously composed of mat and cushion tundra,
sedge-grass tundra,low shrub types with birch and willow
predominant,and alder-dominated tall shrub.
The southeast portion of the middle basin has extensive flat
areas covered by low shrubland and woodland conifer communities.
The flats in the lower Oshetna River and Lake Louise area are
spruce woodland (Viereck and Dyrness 1980).
Each of the transmission corridors crosses several vegetation
types.The Healy-to-Fairbanks transmission corridor includes
ridges,wet flatland,and rolling hills with areas of open
spruce,open deciduous,and mixed forest;shrublands;and wet
E-3-192
3 -BOTANICAL RESOURCES
tundra.The Willow-to-Anchorage transmission corridor passes
through closed birch forest,mixed conifer-deciduous forest,wet
sedge-grass marshes,and open and closed spruce stands.The
Willow-to-Healy intertie corridor traverses a variety of vegeta-
tion types,from closed spruce-hardwood forests in the south to
tundra and shrubland in the north.
3.1.2 -Floristics
Floristics surveys were made in the Susitna Basin and intertie
corridor by McKendrick et ale (1982)and Commonwealth Assoc.
(1982),respectively.These provided information on the numbers
and distribution of plant species which occur within portions of
the project area.
The following floristics data are summarized from McKendrick et
ale (1982)and Commonwealth Assoc.(1982),where further details
may be fou nd •
(a)General
In the region including the Watana and Gold Creek water-
sheds,the downstream floodplain,and the intertie corridor,
295 vascular plant species belonging to 151 genera and 57
famil ies were identified (McKendrick et ale 1982)(Appendix
30).Two hundred fifty-five species were identified in the
Watana and Gold Creek watersheds,and 76 species downstream
from Gold Creek.
Plant families in the Watana and Gold Creek watersheds
having the most represented species were the Compositae
(Asteraceae),Salicaceae,Rosaceae,Gramineae (Poaceae),
Cyperaceae,and Ericaceae.Within the non-vascular flora,
11 genera of lichens (including at least 12 species)and 7
taxa of mosses were identified in these areas.
The downstream floodplain flora was predominantly.a subset
of the Watana and Gol d Creek watershed flora.Of the 76
plant species found downstream from Gold Creek,54 also
occurred in upstream areas.Downstream sites were confined
to the floodplain,which reduced the number of habitats
reprsented and floristic variability relative to the
upstream area.Also,the larger study area and greater time
spent in sampl ing the Watana and Gold Creek watersheds may
in part accou nt for the 1arger number of spec i es fou nd
there.
In the intertie corridor from Willow to Healy,Commonwealth
Assoc.(1982)identified 128 species of vascular plants.
All but 18 of these species were also found in the Watana
and Gold Creek watersheds by McKendrick et ale (1982)
(Appendix 30).Floristics surveys will be conducted in the
Wi1low-to-Cook Inlet and Hea1y-to-Fairbanks transmission
corridors in 1983.
E-3-193
3 -BOTANICAL RESOURCES
(b)Range Extensions
McKendrick et ale (1982)found 22 vascular plant species in
the Watana and Gold Creek watersheds and 9 in the downstream
floodplain corridor which were outside their reported ranges
(see Hulten 1968)(Table E.3.48).However,the Susitna
River drainage upstream from Gold Creek is not well repre-
sented in existing plant collections,and range extensions
may be expected from any additional botanical surveys in the
area.
Two species found in the Watana and Gold Creek watersheds--
Sheldon groundsel and timber oatgrass--represent appreciable
range extensions.Sheldon groundsel had not been officially
reported in Alaska previously,except as possibly present in
the Skagway area.Timber oatgrass had been reported only in
locations near upper Cook Inl et and near Skagway (Hu 1ten
1968).
In August,McKendrick et ale (1982)found a single specimen
of Sheldon groundsel in a mesic (moderately wet)midgrass
community near upper Portage Creek.Its identity has not
yet been verified.Timber oatgrass was identified in August
in the grass portion of a mosaic of low birch and grass
communities between the Maclaren River and the Denali
Highway.
Two other plant occurrences of note were reported by
McKendri ck et a1.(1982).Robbi ns pondweed,a su bmerged
rooted aquatic,was found in Watana Lake (Figure E.3.36).
There has been limited collection of this species in Alaska.
Hu lten (1968)reported it from Summit vi 11 age south of
Healy,and Welsh (1974)indicated that it is known from
south-central Alaska,but is evidently rare.Black spruce,
one of the most common trees found by McKendrick et ale
(1982)in the middle Susitna Basin,had been reported by
Hulten (1968)to be in areas north and south of the middle
Susitna River dra"inage,but not in the drainage.Viereck
and Little (1972),however,did include the Susitna drainage
"in their distr'ibution map of this plant.
Most other range extens ions reported by McKend ri ck et a1 ..
(1982)in the Watana and Gold Creek watersheds were less
noteworthy.Most were extensions to the north (more inland)
from their previous observations.For example,white
bog-orchis had previously been found only near the coast in
Alaska.Northern bog-orchis and sweet gale extensions
i nvol ved sites between areas that were previ ou sly included
in their ranges.Two-flower cinquefo"il and Kane lousewort
extensions were south of their previously reported ranges.
E-3-194
-
r
....
3 -BOTANICAL RESOURCES
In the downstream floodplain corridor,McKendrick et al.
(1982)found nine species outside their ranges as reported
by I-Ulten (1968)(Table E.3.48).One of these,raspberry,
though not reported to extend into the region by Hulten
(1968),was reported by Viereck and Little (1972)to occur
there.Devil's club showed a slight range extension
upriver.Small-fru it bu 11 rush had previ ou sly been fou nd
only in four areas outside southeast Alaska.An unverified
specimen which appeared to be Chamisso's arnica represented
a 1arge extensi on from the Al aska Peni nsu 1a and southeast
Al aska.The presence of enchanter 's nightshade was an
extension inland from coastal regions.Sweet-scented
bedstraw and thinleaf alder were minor extensions,and
baneberry and northern blackcurrant were extensions from the
surrounding areas into the basin.
It is agai n emphasi zed that many of the range extensi ons
reported above were merely the result of more intensive
botanical collections by McKendrick et al.(1982)than had
been made previously and did not represent plants growing in
unexpected environments •
3.1.3 -Contribution to Wildlife,Recreation,
Su bsistence,and Commerce
In the Su sitna watershed as el sewhere,botani ca 1 resou rces make
essential contributions to human activities and land uses.Vege-
tation is necessary for the regional maintenance of surface water
and ground water quality through water retention,determination
of physical and chemical soil properties,and erosion control.
Botanical resources are also essential as fish and wildlife habi-
tat components.The structure and productivity of plant communi-
ties are requisite the occurrence and abundance of wildlife
species within the project area,as discussed further in Section
4 (Wildl ife).Wood is used by local residents for building and
heating homes.In addition,the mosaic of plant comrrunities and
successional stages provides an important aesthetic contribution
(Exhibit E,Chapter 8).Thus,botanical resources directly
support all of the limited human activities and land uses of the
project area (Exhibit E,Chapters 5,7,and 9).
Commercial use of plant resources within the project area has
been limited to small logging operations along the Susitna River
floodplain in the lower basin (ADNR 1982b).Vegetation of the
upper and middle basins is almost entirely u..ndisturbed.Timber
sales are planned for portions of public lands within management
u nits of the Matanu ska-Su sitna-Beluga Cooperative Pl anni ng
Program (ADNR 1982b).Lands with highest forestry potential
withi n the project area are located along nearly the enti re
length of the Susitna River floodplain downstream from the
confl u ence wi th Porage Creek.El even timber sales tota11 i ng
E-3-195
3 -BOTANICAL RESOURCES
approximately 325,100 acres (131,619 ha)within the lower basin
are planned by the Alaska Department of Natural Resources and
Matanuska-Susitna Borough;most are scheduled to begin no earlier
than 1992 (ADNR 1982b).
3.2 -Baseline Description
3.2.1 -Threatened or Endangered Plants
At present,no endangered or threatened plant taxa are officially
listed for Alaska by federal or state authorities;however,37
plant taxa are currently under review by the u.S.Fish and
Wildlife Service (1980a)for possible protection under the
Endangered Species Act of 1973.ivllrray (1980)discusses the
habitats,distributions,and key traits of most of the Al askan
candidate taxa.Searches for these pl ants were made in two
areas--the Watana and Gold Creek watersheds (Figure E.2.36)
(McKendrick et ale 1982)and the intertie transmission corridor
between Willow and Healy (ColT1llonwealth Assoc.1982)(Figures
E.3.35 and E.3.37.
No surveys of candidate taxa were conducted in the downstream
floodplain corridor or the transmission corridors from Healy to
Fairbanks and Willow to Anchorage.Changes in downstream water
flow caused by the project are judged unl ikely to affect any
endangered species,because none of them (Table E.3.49)is nor-
mally found in association with river floodplains.Endangered
plant surveys will be conducted along the Healy-to-Fairbanks and
Willow-to-Anchorage transmission corridors in 1983.
(a)Watana and Gold Creek Watersheds
Table E.3.49 shows the plant taxa on Murray's (1980)list
believed most likely to occur in the Susitna River drainage
and in the habi tats to be affected by construction of the
proposed dams and associated facilities.McKendrick et ale
(1982)conducted ground searches for these candidate taxa
in the following areas of the Watana and Gold Creek water-
sheds:(1)alpine areas near the Susitna and West Fork
Glaciers;(2)lowlands of the upper and middle basins,in-
cluding those of the Maclaren and Tyone Rivers and their
associated ridges,terraces,and periglacial features;(3)
calcareous outcrops and promontories along the Susitna River
near Watana and Kosina Creeks;(4)potential alternative
access routes in the middle basin;and (5)borrow sites
planned for dam construction.These areas were selected
after reviewing the 1 iterature pertaining to the 1 ikely
habitats of endangered plant taxa,conferring with special-
ists in Alaska plants,and conduct"ing discussions with
project geologists to identify calcareous soils (a habitat
component of some of the species in question).
E-3-196
r:c'·1
!"""
I 3 -BOTANICAL RESOURCES
Well-drained rocky or scree slopes were searched in alpine
areas of the upper drainage basin in the steep valleys adja-
cent to the Su sitna and West Fork Gl aci ers.None of the
taxa under federal review was found.
Well-drained t sandy or gravelly ridges and terraces in low-
lands of the upper and middle drainage basins were searched.
Shores of lakes and ox-bow ponds t and peri-glacial features
were emphasized.A trip was made downstream as far as Devil
Canyon t and two 1arge gravel barswithi n the riverbed were
surveyed.None of the taxa under federal review was found
in these lowland surveys.
Several of the taxa listed by Murray (1980)were known cal-
ciphiles (plants that normally grow on calcareous soils).
Three locations with calcareous soils were found in the
project area.One was on the northwest fl ank of Mt.Watana
at about 3700·ft (1128 m)elevation t another on the squth
side of the Susitna River immediately east of its confluence
with Kosina Creek t and the third was on the north side of
the Susitna River about 4.5 m"iles (7 km)west of Watana
Creek.Calciphilic plants were found on two of these sites t
but none of those found was listed by Murray (1980).
Three sites judged by substrate characteristics potentially
to support rare plants were searched along the proposed
access route section from the Denali Highway to Watana
(Figure E.3.37).One site was a sandy blowout area on the
northwest side of Deadman Mountain;one was a series of dry
ridges (probably glacial moraines or terraces)on the south
side of Deadman Mountain;and one was an area of windblown
ridges on the east side of Deadman Mountain.No candidate
threatened or endangered taxon was fou nd at any of these
sites t nor along any of the other proposed access corri-
dors.
-Vegetation in the vicinity of borrow sites proposed for dam
construction (Figure E.3.37)was surveyed in July 1981.No
candidate threatened or endangered taxon was found.
(b)Willow-to-Healy Intertie
The Willow-to-Healy intertie corridor (Figures E.3.35 and
E.3.37 was surveyed for the presence of Smelowskia borealis
var.villosa t Taraxacum carneocoloratum t and Monti a
bostockii t all of which appear on Murray's (1980)list
(Table E.3.49).Geologic and topographic maps were used to
identify potential habitat areas for these taxa within the
intertie corridor.None of the candidate taxa was found in
the locations surveyed (Commonwealth Assoc.1982).
E-3-197
3 -BOTANICAL RESOURCES
(c)Summary
In summary,the Susitna River watershed upstream from Gold
Creek was surveyed at selected habitat sites for plant taxa
under cons i derat i on for threatened or endangered statu s.
Access routes,borrow areas,and the intertie corridor were
also surveyed for the presence of these taxa.No candidate
threatened or endangered pl ants were fou nd.Fu rther endan-
gered plant surveys will be made in the Healy-to-Fairbanks
and Willow-to-Anchorage transmission corridors in 1983.
3.2.2 -Plant Communities
(a)Methods
Vegetation of the project area was mapped at three different
scales by McKendrick et ale (1982),using photo-interpre-
tation of high-altitude (U-2)color infrared photographs and
LANDSAT imagery,followed by confirmation of vegetation
types in the field.Plant communities were classified in
accordance with Viereck and Dyrness (1980).The Watana and
Gold Creek watersheds (Figure E.3.36)were mapped at a scale
of 1:250,000 (Figure E.3.38).The middle basin (Gold Creek
to the Tyone River,RM 246.5)was further mapped at a scale
of 1:63,360,encompassing land bordering the Susitna River
to a distance of about 10 miles (16 km)and thus including
all of the construction and borrow areas associated with the
proposed Watana and Devil Canyon dams,an of the Watana-
to-Devi 1 Canyon and Devi 1 Canyon-to-Gol d Creek access and
transmission routes,and approximately the southern one
third of the Denali Highway-to-Watana access route and
associated borrow areas (Figures E.3.39, E.3.40,and
E.3 .41).The Healy-to-Fairbanks and Wi 11 ow-to-Anchorage
transmission corridors were also mapped at a scale of
1:63,360 (Figures E.3.48 through E.3.52).Vegetation maps
of the intertie corridor,presented at a scale of 1:250,000
in Commonwealth Assoc.(1982),were adapted from a map
preyi ou sly prepared by the Joi nt Federal-State Land Use
Pl anni ng Commi ssi on for Al aska (l973)and adapted
subsequently by the U.s.National Park Service (1976).
McKendrick et ale (1982)prepared vegetation maps of the
Watana and Devil Canyon impoundment,construction,and
borrow areas,and the Susitna floodplain downstream to
Talkeetna,at a scale of 1:24,000 (Figures E.3.53 through
E.3.65).Wetland vegetation types were mapped by McKendrick
et ale (1982)at a scale of 1:24,000 from the Oshetna River
to the Devil Canyon damsite,using the system of Cowardin et
ale (as adopted by the Fish and Wildlife Service (l980b).
(Figures E.3.66 through E.3.73.The wetlands maps were
based on the 1:24,OOO-scale vegetation maps.
E-3-198
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,....
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3 -BOTANICAL RESOURCES
Whereas the vegetation maps show definite boundaries between
vegetation types,such lines of demarcation do not exist in
the fi el d and are imposed by the judgment of the carto-
grapher.Another consi derat i on is that the small est feas-
ible units mappable at the 1:250,000,1:63,360,and 1:24,000
scales are about 642 acres (260 hal,about 40 acres (16 hal,
and about 7 acres (3 hal,respectively.Therefore,vegeta-
tion types shown on the larger scale maps and tables derived
from them are sometimes absent from the smaller scale
mapping and tables (McKendrick et al.1982).
The cl assifi cati on system proposed by Vi ereck and Dyrness
(1980)is a hierarchical system based on the characteristics
of the vegetation itself.-It is composed of four formations
for terrestrial vegetation:forest,tundra~shrubland,and
herbaceous vegetation;and one formation for aquatic vegeta-
tion.These formations constitute Level I of the classifi-
cation system.At the finest level of re~:olution (Level V),
units are discrete plant comnunities.Levels II,III,and
IV are intermediate in resolution.In most cases,the Level
III names were used for mapping;however,Level IV names
were used for forested areas on the 1:24,000 and
1:63,360-scale maps.A total of 19 categories were used to
map vegetation at the 1:250,000 sCcle;25 were used on the
1:63,360-scale maps;~nd 21 were used on the 1:24,OOO-scale
maps.
Vegetation studies by McKendrick et ale (1982)were
conducted during thE'summers of 1980 and 1981.The stuEly
area during 1980 included the Watana and Gold Creek
watersheds and the flocdplain of the Susitna River from Gold
Creek to Talkeetna.[)Jring 1981,the Jownstream floodplain
received further attention,and the Healy-to-Fairbanks and
Willow-to-Anchorage transmission corridors were mapped,in
addition to further surve~!s upstream from Gold Creek.As
shown in Figure E.3.33,areas closer to or including the
proposed impoundment,dam,and ancillary facility locations
were mapped at progressively larger scales,reflecting the
relative extents of direct disturbance expected to result
from the project in these areas (McKendrick et al.1982).
For confirmation of mapped vegetation types,high-altitude
(U-2)color photography at a scale of 1:120,000 with
overlays of delineated vegetation units was taken into the
field.More attention was given in the field to the areas
mapped at larger scales (i.e.,greater resolution),but
locations throughout the entire study area were checked to
include as many reprsentative terrain types and physio-
graphic areas as feasibile.Ground-truth surveys
E-3-199
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-
r
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3 -BOTANICAL RESOURCES
emphasized vegetation types which were especially difficult
to interpret from aerial photography (McKendrick et ale
1982).During field checking of the Healy-to-Fairbanks and
Willow-to-Anchorage transmission corridors,color infrared
photographs at scales of 1:63,360 and 1:120,000,black and
white1:48,000-scale prints,and 1:12,000-scale true-color
photographs were variously used (McKendrick et ale 1982).
Additional vegetation mapping of the project area utilizing
recently available real-color and color infrared aerial
photography is currently planned.This mapping has three
objectives:(1)to provide a quantifiable data base for
preci se type and areal extent of moose browse withi n the
Watana and Gold Creek watersheds;(2)to del ineate
vegetation comrrunities characteristic of wetlands (as
defined by Cowardin et ale 1979)to a level of detail that
will usefully sopport facility siting and design as well as
preparation of permit applications required by Section 404
of the Clean Water Act;and (3)to provide general mapping
of vegetation types based on improved aerial imagery as a
data base for refined impact assessment and design support.
The mapping program will provide two vegetation map
products:a detailed 1:24,000-scale map of wetland vegeta-
tion and moose browse types delineated to classification
Level IV of Viereck,Dyrness,and Batten (1982);and a
1:63,360-scale map of vegetation types delineated to classi-
fication Level III of Viereck and Dyrness (1980).The
1:24,000-scale map will cover lands in the immediate project
vicinity including all potential impact areas:the impound-
ments,damsites,borrow sites,construction camps and vil-
lages,access corridors,and the Watana-to-Gold Creek trans-
mission corridor.The 1:63,360-scale map will cover the
Watana and Gold Creek watersheds including the access
corridor to the Denali Highway.
Both vegetation maps will be field-checked following initial
photointerpretation with subsequent refinements.The
1:24,000-scale map will provide categorized detail for moose
browse and wetl and vegetation beyond the 1imits of the
photography,based on field data.Appl ications of these
maps to impact assessment and mitigation planning are dis-
cussed in Sections 3.3, 3.4,and 4.4.It is expected that
preliminary mapping will be available by June 30,1983.
E-3-20l
3 -BOTANICAL RESOURCES
Methods used for the qualitative and quantitative character-
i zat i on of vegetat i on types are descri bed in detail by
McKendrick et ale (1982).The 64 locations and associated
vegetat i on types su rveyed in the Watana and Gold Creek
watersheds during the summer of 1980 are indicated in Table
E.3.50 and Figure E.3.74.
At these locations,plant species composition and community
structure determinations were made;and data on elevation,
slope,aspect,and landform also were gathered to relate to
plant species composition.
The cover contributed by each plant species was measured
within a series of vertical layers as percent area of each
layer.The ground layer was defined to be all herbaceous
and woody species less than 1.6 feet (0.5 m)tall.The
shrub 1 ayer included woody species tall er than 1.6 feet
(0.5 m)with a diameter at breast height (dbh)less than
1 inch (2.5 cm).The understory layer consisted of woody
species between 1 inch (2.5 cm)and 4 inches (10.0 cm)dbh.
Overstory vegetation contained species larger than 4 inches
(10.0 cm)dbh.This classification approach is used here to
describe the vertical layering within plant coml11.lnities of
the project area.
Forest cOml11.lnities were defined as those with at least 10
percent cover by tree species regardless of tree height.
Shrubland coml11.lnities had at least 25 percent cover of
erect-to-decumbent shrubs but were not located beyond the
elevational limit of trees.Tundra stands were those com-
munities above or beyond the elevational limit of trees and
were dominated by shrub or herbaceous species.
Forests were divided into subtypes according to the dominant
trees (conifer,deciduous,or mixed).Deciduous and coni-
fer types had at least 75 percent of the tree cover provided
by either deciduous or coniferous trees,respectively.
Mixed types had smaller percentages of each.It should be
noted that white and bl ad spruce and common ju ni per were
the only coniferous species in the study area.
Each forest subtype was further classed as woodland,open,
or closed,depending on percent of tree canopy cover.The
woodl and type stands conta i ned between 10 percent and 25
percent tree cover.Open stands contained 25 to 50 percent
tree cover,and closed stands had over 50 percent tree
cover.
E-3-202 r---,
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3 -BOTANICAL RESOURCES
Shrub comrrunities were classed as open or closed by percent
cover,open indicating up to 50 percent cover.Shrub vege-
tation was also classed as tall or low,with tall shrub
di sti ngu i shed primari ly by the presence of Sitka al der fre-
quently 6 to 12 feet (2 to 4 m)in height.
Low shrub cOlTllllJnities were about 3 to 5 feet (1 to 1.5 m)
tall and were classified into three subtypes:those domi-
nated by birch,willow,and a mixture of the two.Resin and
dwarf arctic birch were the predominant birches;and willows
were typically represented by such species as diamondleaf
and feltleaf willow,both important as moose browse.
Aquatic vegetation within the Watana and Gold Creek water-
sheds was examined during August 1980.In order to obtain
site-specific information on aquatic plant species,24 sel-
ected ponds and lakes and their adjacent uplands were sur-
veyed on foot from Devil Canyon (RM 152)to the confluence
of the Susitna and Oshetna Rivers (RM 233)(Figure [,3.75).
During the surveys,species composition,dominance,and
tota 1 cover (re1at i ve to the amou nt of water)were
estimated.Elevation,estimated rooting depth,and width of
surrounding wetland area were recorded.Surrounding wetland
was limited by definition to the Lacustrine-Limnetic-
Emergent Wetland-Vascular wetland class of Cowardin et ale
(1979)~Many remai ni ng ponds and 1akes were exami ned by
helicopter overflights.
Quantitative descriptions of downstream floodplain plant
comnunities were made during the summer of 1981 at the 29
1ocat ions shown in Fi gu re £.3.34.Vegetat i on cover by
species was measured along transects.Density of woody
species was determined by counting individual stems of
plants within specific height ranges growing inside desig-
nated measurement plots.Age,height,and diameter at
breast height (dbh)of low shrubs,tall shrubs,and trees
were measured for randomly selected plants along the tran-
sects,and the age of each measured tree or shrub was deter-
mined by counting growth rings taken from cross-sectional
cuttings or cores.Crown dominance,a measure of which
species within a stand were capturing the canopy sunl ight,
was evaluated as follows:(1)open growth (not encoun-
tered),(2)dominant -received sunlight from above and the
sides,(3)codominant -received sunlight from above,but
not from the sides,(4)intermediate -plant barely reached
main canopy,(5)overtopped -plant was below general level
of canopy,(6)subordinate -below the overtopped category,
and (7)ground -the lowest level.The ground elevation of
each floodplain stand relative to river surface elevation
was measured by rod-and-level technique at two or three
E--3-203
3 -BOTANICAL RESOURCES
different times during the summer of 1981.Time of day for
each measurement was recorded for later reference to rate of
river flow.
(b)Watana and Gold Creek Watersheds
Figure E.3.38 shows the general distribution of vegetation
in the Watana and Gold Creek watersheds,and Figures E.3.39
through E.3.41 and E.3.53 through E.3.65 provide greater
detail.Table E.3.50 and Figure E.3.74 indicate field
sampling locations and associated vegetation types
characterized for ground truth and floristics during June,
July,and August 1980 (McKendrick et ale 1982).Hectares
and percentages of total area covered by vegetation types in
the Watana and Gold Creek watersheds are shown in Table
E.3.51,based on mapping at a scale of 1:250,000 (Figure
E.3.38)(McKendrick et ale 1982).Table E3.52 shows
hectares and percentages of total area covered by vegetation
types in the 10-mil e (l6-km)area on each side of the
Susitna River from Gold Creek to the Maclaren River,based
on mapping at a scale of 1:63,360 (Figures E.3.39 through
E.3.41 (McKendrick et ale 1982).
The structure and distribution of vegetation types at eleva-
tions below tundra in this area are strongly influenced by
past fires,evidenced by fire scars on the trees.Post-
fi re successi on for black spruce stands typically proceeds
from the initial herbaceous and shrubby stages to young
black spruce stands to dense and finally decadent black
spruce/moss communities (Van Cleve and Viereck 1981).Post-
fire succession in white spruce stands includes the initial
herb and tree seedling stage;the shrub-tree sapling stage;
and the dense hardwood stage of aspen,birch,or a mixture
of aspen and bi rch.From thi s poi nt the stand proceeds
through a matu re hardwood-spruce seedl ing stage,a mi xed
white spruce-hardwood stage,and fi nally a matu re white
spruce stage (Van Cleve and Viereck 1981).Most of the
herbaceous,shrubby,deciduous,and mixed forest cOlllTlJnities
identified and described below may be successional stages in
the process of transition to black or white spruce forest.
(i)Forests
Forest vegetation types were located at lower eleva-
tions and covered approximately 21 percent total area
(860,481 acres,348,232 hal of the Watana and Gold
Creek watersheds.The mean elevation of forest areas
sampl ed was 1716 feet (523 m)(range 1100 to 2600
feet,340 to 790 m).
E-3-204
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F'"
I
,.,..
!
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3 -BOTANICAL RESOURCES
Forested comrrunities in this area were similar to
those described by Viereck (1975).Black spruce
generally occurred on wetter sites than white spruce,
and both spruce species occurred on colder sites than
those of deciduous or mixed forests.Bl ack spruce
forests on poorly drained soils are discussed as
wetlands "in Section 3.2.3.Closed forests occur on
sites warmer than those of open forests.Deciduous
and mi xed forest stands in the proj ect a rea were
considered earlier successional stages of the conifer
stands (Viereck 1970,1915;Hettinger and Janz 1914).
-Coniferous Forest
Coniferous forests covered approximately 19 percent
total area (160,045 acres;301,586 ha)in the
Watana and Gol d Creek watersheds and consi sted of
spru.c.e stands with a majority of either white or
black spruce.These forests contained a well-
developed ground layer with a high percent cover
(94 percent)(Tables E.3.53 through E.3.56).The
1 ayering structures of white and bl ack spruce
stands were similar,except that white spruce
stands usually had a greater overstory cover (35
percent compared to 14 percent),a refl ecti on of
the generally larger cover area of individual
mature white spruce trees (Tables E.3.54 and
E.3.55).
As evident in Tables [.3.54 and [.3.55,open white
'spnJce and black spruce stands differed greatly
with respect to species composition and percent
cover contributed by the two spruce species within
the vertical strata.In the open white spruce
stands sampled,black spruce was absent;whereas in
the open bl ack spruce stands,total bl ack spruce
cover (22 percent)and white spruce cover (11 per-
cent)were nearly equal.White spruce percent
cover (13 percent)was greater in the overstory
layer because of the larger cover area of individ-
ual white spruce trees as compared to black spruce
(5 percent cover)which had reached the overstory.
Core sampl i ng indicated that 1 arge white spruce
ranged from 34 to 18 years in age and large black
spruce from 11 to 111 years.Several white spruce
stands examined appeared to be recovering from past
di stu rbance,perhaps fi re;bl ack spruce stands
showed less signs of disturbance.
[-3-205
3 -BOTANICAL RESOURCES
Open spruce stands were usually found on riverine
slopes or terraces at elevations averaging 1600
feet (487 m)(range 1100 to 1950 feet;340 to
590 m)and covered approximately 1 percent of the
total area.The cover contributed by the white
spruce trees was concentrated in the overstory
1 ayer (35 percent overstory,1 percent shrub),
whereas percent cover provided by black spruce
trees was proportionately greater in the shrub
layer (5 percent overstory,8 percent shrub)
(Tables £.3.54 and E.3.55).Canopy cover of the
grou nd 1ayer in open spruce forests normally
exceeded that of the overstory.Bl ack spruce
stands contained low shru bs,such as crowberry,
northern Labrador tea,bog blueberry,and mountain
cranberry,in the ground layer.Bluejoint was the
predomi nant grou nd 1ayer speci es by cover in open
white spruce stands.
Cover of feather mosses in open stands of both
white and black spruce approximated that of the
trees.Low shrubs,such as crowberry,northern
Labrador tea,bog blueberry,and mountain cran-
berry,accounted for much of the woody ground layer
in open black spruce stands (Table E.3.55).Pre-
dominant herbaceous species common to both types of
open stand were twinflower and horsetails.
All woodland spruce stands surveyed by McKendrick
et ale (1982)were bl ack spruce.Th is was the most
widespread forest type and covered approximately 12
percent of the total area of the Watana and Gal d
Creek watersheds.Unlike open spruce forest,
woodland stands were composed of scattered,stunted
trees,and the overstory was almost negligible
(Table E.3.56).This vegetation type was usually
found on relatively level benches with poorly
drained soils at elevations averaging 2,046 feet
(range 1600 to 2600 feet;490 m to 740 m).The
trees were usually too small to qualify for the
overstory layer because trunks were generally less
than 4 inches (10 em)dbh.In woodland spruce
stands,sphagnum mosses,not feather mosses,were
the most predominant cover species (62 percent
cover);other important ground layer species
included sedges,woodland horsetail,and low shrubs
similar to those found in the open spruce stands
{Table E.3.56}.
E-3-206
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3 -BOTANICAL RESOURCES
Balsam poplar is the first tree to appear during
successional develoJl1lent of vegetation an allurial
deposits.Bal sam popl ar trees provided about 75
percent cover in the overstory,but contributed
relatively small cover(S percent)within the
understory and shrub layers of balsam polar stands
(Table E.3.57).
Closed paper birch stands occurred on steep,
usually south-facing slopes that had typically been
subjected to recent di stu rbance,as described by
Hettinger and Janz (1974)for northeastern Alaska.
The layer structure was similar to that of closed
balsam poplar stands--73 percent overstory cover,a
well-developed ground layer (95 percent cover),and
relatively minor cover in the shrub and understory
1 ayers (3 and 9 percent,respecti vely)(Tabl e
E.3.58).Frequently the overstory contained a few
scattered white spruce.
Trembling aspen stands were infrequently found on
the upper portions of quickly·draining,dry,
south-faci ng slopes.Thei r general structure was
similar to that of other closed deciduous stands in
that there were well-developed overstory and ground
layers (80 and 85 percent,respectively),but
poorly developed shrub and understory 1 ayers (5
percent for both)(Table E.3.59).
-Mixed Conifer-Deciduous Forest
Mixed conifer-deciduous forests covered approxi-
mately 2 percent of the total area of the Watana
and Gold Creek watersheds.This vegetation type
had mean overstory cover values intermediate
between mean cover values for spruce stands and
those for deciduous stands.This forest type was
typically dominated by white spruce and paper
birch.Elevations for mixed conifer-deciduous
forest average 1530 feet (466 m)(range 1200 to
2250 feet;370 to 690 m),with closed stands having
a mean elevation near 1394 feet (425 m)(range 1300
to 1450 feet;400 to 440 m),and open stands
occurring around 1581 feet (482 m)(range 1200 to
2250 feet;370 to 690 m).•Most of the 1 arger
stands were found on slopes downstream from Tsusena
Creek (Fi gu re E.3 .36)•These were successi onal
stands which developed as spruce replaced deciduous
trees.
E-3-207
3 -BOTANICAL RESOURCES
Mixed conifer-deciduous forest had a well-developed
ground layer with predominant species including
b1uejoint,bunchberry,woodland horsetail,and
knight's plume-moss (Pti1ium sp.)(Tables E.3.60
and E.3.61).Overstory cover in closed mixed
stands is about 60 percent and that in open mixed
stands is approximately 38 percent.Overstory
height was sometimes up to 66 feet (20 m).The dbh
of individual trees "in these two-species
overstories ranged from 0.5 to 1.0 feet (15 to
30 cm).
Cores from larger trees indicated that mature birch
in mi xed stands averaged about 90 years 01 d or
older.Rotten centers precluded accurate aging in
older birch trees.White spruce ages ranged from
50 to 204 years,with most trees older than 100
years.
Pl ant speci es compositi on and abu ndance differed
between 0 pen and closed stands of mi xed conifer-
deci du ou s forest.The shrub 1ayer contri buted
greater cover (17 percent)in open stands than in
closed stands (4 percent)because tall blueberry
willow was more abundant there than in closed
stands (Tables E.3.60 and E.3.61).
(ii)Tundra
Tundra communities covered 24 percent (975,267 acres,
394,685 ha)of the Watana and Gold Creek watersheds
and usually occurred above the 1 imit of tree growth
(Figure E.3.38).Most of the well-vegetated commun-
ities occurred in flat to gently sloping areas.
Sparser vegetation was present on steep or rocky
terrain.Although tundra species composition was
highly variable,four distinct subtypes were identi-
fi ed in areas 1arge enough to map--wet sedge-grass
tundra,mesic sedge-grass tundra,herbaceous alpine
tundra,and closed mat and cushion tundra.
Wet sedge-grass tundra cormu niti es covered a small
amount of the total area (0.3 percent)and occurred
at a mean elevation of 1926 feet (587 m)(range 1400
to 2550 feet,430-780m)in wet,depressed areas with
poor drainage.They had almost 100 percent vegeta-
tion cover,with most species occurring in the ground
layer (Table E.3.62).Predominant herbaceous species
were water sedge,Bigelow sedge,sphagnum moss,and
b1uejoint.The shrub layer,when present,contained
scattered individual willows.There was
E-3-208
f~)
(--::---,
-
.-
-
-
3 -BOTANICAL RESOURCES
usually a large amount of organic matter in soils of
wet sedge-grass communities,and in some cases a
thick organic layer overlaying mineral soil.Wet
sedge-grass tundra is noted as a wetland type in
Section 3.2.3 •
Mesic sedge-grass tundra was the largest tundra sub-
type (11 percent cover)and occurred at a mean eleva-
tion of 4502 feet (1372 m)on well-dra.ined,rolling
uplands.The underlying soil was well-developed in
some areas,but in others the soi 1 was patchy and
interspersed with rocks.Mean Vegetation cover was
65 percent for the two 1ocat ions surveyed (Tab1 e
E.3.63).All vegetation was in the ground layer,and
species were usually 1ess than 1 foot (30 cm)tall.
Bigelow sedge was the most common species and
accounted for almost half of the total vegetation
cover.
Two types of herbaceous alpine tundra were found in
the Watana and Gold Creek watersheds,although only
one type,herb-sedge tundra,was predominant in areas
1arge enough to map.Herb-sedge communities covered
less than 1 percent of the total area and occurred at
e1 evati ons of about 4249 feet (1295 m)(range
unavailable),near the glaciers of the upper basin
(particularly the West Fork Glacier)on gentle,
well-drained slopes with relatively well-developed
soil s.Vegetati on cover in herb-sedge tundra was
nearly 100 percent.A 1 ist of the 42 species found
in one stand of herb-sedge tundra is shown in Table
Eo 2.64.Cover of each species cou1 d not be
determined because of the complex vegetation pattern.
The other type of herbaceous alpine community was
present in small,isolated rocky areas.Small forbs
and sometimes shrubs grew in pockets of mi nera1 soil
imbedded between the rocks.
The fourth major type of tundra community found with-
in the Watana and Gold Creek watersheds was mat and
cushion tundra (total 4 percent cover),found at high
elevations (3280 feet;1000 m)(range 2600 to 4000
feet;302 to 1219 m)on dry,windy ridges.
Vegetation cover was about 75 percent and was usually
less than 8 to 12 inches (20 to 30 cm)tall (Table
E.3.W16).Li chens and low mat-formi ng shrubs were
major constituents.Soils were shallow and coarse.
Up 1ands withi n the Gold Creek watershed suppo rted
extensive areas of a mixed vegetation type consisting
E-3-209
3 -BOTANICAL RESOURCES
of interspersed mat and cushion and sedge-grass
tundras (9 percent total area)(Fi gure E.3.38).
(iii)Shrubland
Shrub 1and vegetati on types were the most preval ent
of all vegetation types and comprised almost 40
percent cover in the Watana and Gol d Creek water-
sheds.Including approximately 65 pl ant species,
shrublands generally occupied areas at higher
elevations than forest communities,but at lower
elevations than tundra types.Two main types were
found:tall and low shrub.Most shrublands,
particularly the low shrub,were found on extensive,
fairly level benches at mid-elevations throughout the
Watana and Gol d Creek watersheds.Less extensi ve
areas,usually tall shrubs,were found on steep
slopes above the river.Tall and low shrub types
were further di vi ded by percent shrub cover into
closed and open types.
-Tall Shrub Types
Tall shrub communities covered approximately 8
percent of the total area and were domi nated by
Sitka alder and were found mostly on steep slopes
above the Susitna River or sometimes above fl at
benches at a mean elevation of 1880 feet (573 m)
(range 1600 to 2550 feet;490 to 780 m)(Fi gure
E.3.38).Many of these stands were 7 to 13 feet (2
to 4 m)tall.Approximately 25 species were
identified in the alder stands (Table ~.3.66).
Alder stands frequently occurred as narrow strips
through other vegetation types on the slopes
adjacent to the Susitna River.Alder would also be
present in ri ngs at a parti cul ar el evati on around
mountains or in strips along tributary streams,
such as Portage Creek.Closed stands had almost
complete vegetation cover,contributed primarily
by the ground layer and understory (Table E.3.66).
One open alder stand surveyed had less vegetation
cover than the closed stands (85 percent and 96
percent cover,respectively),with greatest percent
cover in the understory layer (Table E.3.67).
Bluejoint was the predominant ground layer species
in open and closed stands.
E-3-210
-
-
r
3 -BOTANICAL RESOURCES
-Low Shrub Types
Low shrub vegetation types were found to be common
in the ~atana and Gold Creek watersheds where they
covered 32 percent of the total area.Low shrub
communities were widespread on the extensive,rela-
tively flat river benches (mean elevation:2562
feet,781 m)(range 2100 to 3200 feet,640 to 980
m),where soils were frequently wet and gleyed,but
usually wi thout standi ng water.Bi rch and wi 11 ow,
generally 3.3 to 4.9 feet (1.0 to 1.5 m)tall,were
predominant in both separate and mixed stands.The
cover percentages of ten closed and two open low
shrub stands sampl ed are shown in Tabl es E.3.68
and E.3.69,respectively.
Bi rch shrub stands were usually domi nated by resi n
birch 3.3 feet (1 m)tall,and contained several
other low shrub species,especially northern Labra-
dor tea.Predominant ground layer species were bog
blueberry,mosses and lichens.Willow shrub stands
were usually in wetter areas than birch shrub
stands.Diamondleaf willow was commonly predomin-
ant,forming thickets along small streams at high
elevations.Because of the wetness,these communi-
ties were usually less botanically diverse than
birch shrub stands.Water sedge,northern Labrador
tea,and bog bl ueberry were the predomi nant ground
1ayer species.
-
-
(i v)
(v)
Herbaceous Communities
Two herbaceous community types were found in the
Watana and Gol d Creek watersheds.Grassl ands domi n-
ated by bl uejoi nt were present on 1evel to sloping
areas at lower elevations along the Susitna River and
Portage Creek (less than 1 percent total area)(Table
E.3.52 and Figure E.3.53 through E.3.65).Herbaceous
communities were too small to map at a scale of
1:250,000 and do not appear in Table E.3.51.
Herbaceous pioneer communities (too small to map)
.were present on recently vegetated gravel and sand
bars where soils had little organic matter and often
consisted primarily of cobble.Pioneer species
included horsetails,lupines,and alpine sweetvetch.
Aquatic Vegetation
Lakes and ponds surveyed for aquatic vegetation are
shown in Figure E.3.75.Aquatic species identified
duri ng these surveys are 1i sted by site in Tabl e
E-3-211
3 -BOTANICAL RESOURCES
E.3.70.A summa ry of the domi nant aquati c speci es
and factors which may influence their locations in
and around many of the water bodies in the Watana and
Gold Creek watersheds is presented in Figure E.3.76.
Bur reed and yellow pond 1i ly probably contri buted
more to total cover than all other aquatic species
combined.Yellow pond lily,a submerged species with
large floating leaves,was particularly prominent and
formed 1arge beds in several water bodi es.It was
absent along the edges of ponds and appeared to grow
best at depths rangi ng from 2.a to 7.a feet (0.6 to
2.1 m),frequentl y formfng a band around ponds and
lakes between the shallows and deep water.Bur reed,
in contrast,frequently dominated the shallows of the
ponds from 0.5 to 2.0 feet (0.15 to 0.60 m)in depth.
Horsetail,mare I s tail,and bl adderwort were al so
common in these shal.lows.Horsetail was common on
rocky bottoms where little other vegetation was
present.Bladderwort was prominent in shallows
having a mud bottom or a bottom of organic matter.
Along the edges of water bodies,sedges appeared to
contribute more to total cover than all other edge
species combined.They were the prevalent species of
the pond shallows,along the pond periphery,and also
on floating mats when they are present.
Lakes and ponds wi th gently sloping substrates had
more aquatic pl ants,both submerged and emergent,
than did water bodies with steeply sloping sub-
strates;but above 3100 feet (945 m)in elevation,
there was usually sparse aquati c vegetati on cover
regardless of substrate morphology.Rocky bottoms
supported less aquatic vegetation than did mud or
sand bottoms.Floating mats of vegetation were
sometimes a part of the associated emergent wetland.
These mats were domi nated by sedges,sphagnum moss,
and other common bank species.
Watana Lake was uni que in that it was domi nated by
Robbins pondweed,a submerged rooted aquatic species
that grows in water from about 4.0 to 8.0 feet (1.2
to 2.4 m)in depth.The reason for the lack of other
vascul ar pl ants in Watana Lake and the presence of
Robbi ns pondweed is not understood.(See Secti on
3.1.2(b)for further discussion of this species.)
(vi)Unvegetated Areas
Unvegetated areas were found to cover 15 percent of
the total area (601,422 acres,243,392 hal of the
E-3-212
-
3 -BOTANICAL RESOURCES
Watana and Gold Creek watersheds and 6 percent of the
total area (66,665 acres,26,979 ha)16 km on either
side of the Susitna River from Gol d Creek to the
Maclaren River.Three classes of unvegetated area -~
water,rock,and snow and ice --were identified and
mapped (Figures E.3.38,E.3.39 through E.3.41,and
E.3.53 through E.3.65).Lakes and streams were
included in the water category.Lakes were generally
found along flat benches and ranged in size from
sma 11 ponds to 1arge 1akes such as Bi g Lake
(approximately 112 acres;450 ha).Rock was bedrock
or deposited geologic materials supporting little or
no vascular vegetation.Rock occurred as
outcroppings at high elevations,as steep cliffs
along the Susitna River and tributaries,or as
unconsolidated gravel in newly deposited river bars.
These river,bars were usually first colonized by
horsetails,mountain-avens,and willows.Snow and
ice included permanent snowfields and glaciers;these
were most common at the northern end of the study
area in the Alaska Range,but some occurred near the
southern boundary in the Talkeetna Mountains.
(vi i )Comparison of the Watana and Gold Creek Watersheds
Tables E.3.71 and E.3.72 provide an approximate
comparison of vegetation communities and their
relative areal extents for the Watana and Gold Creek
watersheds,respectively (Figure E.3.36).A
comparison of percent total area covered by each
vegetation type in the two areas (Tables E.3.71
and E.3.72)shows several notabl e di fferences whi ch
are apparent also from inspection of vegetation
patterns mapped at the 1:250,000 scale (Figure
E.3.38).Differences in the abundance of vegetation
types from one area to another are reflected in the
impact analyses for botani cal resou rces and wil dl ife
(Exhibit E,Chapter 3,Sections 3.3 and 4.3,
respect i ve ly).
Although the Watana and Gol d Creek watersheds had
nearly equal percent cover by forest,conifer forest
was much more abundant in the Watana watershed (21.
percent Watana,4 percent Gol d Creek).In the Gol d
Creek watershed,conifer forest types were confined
mainly to north-facing slopes and adjacent benches in
the Fog Lakes and Stephan Lake vi ci niti es;whereas
conifer forest occurred extensively throughout
eastern,central,and northwestern areas of the
Watana watershed.
E-3-213
3 -BOTANICAL RESOURCES
By contrast,mi xed forest types were far more abun-
dant in the Gold Creek watershed (0.5 percent Watana,
18 percent Gold Creek),particularly along the main-
stem Susitna River;Devi 1,Cheechako,and Portage
Creeks;and the Indian River.Percent cover by
deci duous forest was very sma 11 for both the Watana
and Gold Creek watersheds.Balsam poplar stands (too
sma 11 to map)were present in the Sus itna Ri ver
floodplain and along tributary streams.The percent
of total area covered by tundra vegetati on types
within the Gold Creek watershed was nearly twice that
of the Watana watershed (22 percent Watana,41
percent Gold Creek).This difference was mainly due
to the predominance of mixed mat and
cushion/sedge-grass tundra on the uplands to the
north and south of the Devil Canyon impoundment area,
and to the rel at ive scarcity of thi s type in the
Watana watershed (6 percent Watana,33 percent Gold
Creek)•
Mesi c sedge-grass tundra was more abundant in the
Watana watershed,where it occupied high-elevation,
we ll-drai ned upl ands in the northeast reaches of the
Talkeetna Mountains south of the Susitna River (13
percent Watana,0.3 percent Gold Creek).
The distribution of shrubland vegetation varied
greatly between the Watana and Gold Creek watersheds
(40 percent Watana,28 percent Gold Creek).Tall
shrub vegetation (alder stands)was abundant on steep
slopes along the drainages of the Gold Creek water-
shed,occupying extensive areas north of the Susitna
Ri ver.Large stands of tall shrub vegetati on were
much less abundant in the Watana watershed (7 percent
Watana,18 percent Gold Creek).
Low shrub vegetation,predominantly mixed birch-
wi 11 ow sh rub,was extremely abundant throughout the
southern,central,and eastern portions of the Watana
watershed and covered a greater percent of the total
area (34 percent)than any other vegetation type.
Low shrub stands in the Gol d Creek watershed were·
much more local,as on the slopes between Tsusena
Creek and Swimmi ng Bear Lake,and covered only 11
percent of the total area.
(c)Devil Canyon to Talkeetna
The Susitna Ri ver from Devi 1 Canyon (RM 155)to Tal keetna
(RM 103)flows through a steep canyon that opens out near
Talkeetna.Vegetation is established slowly in the flood-
E-3-214
r"'"·-~I
,.....
~
I
3 -BOTANICAL RESOURCES
plain until sufficient silts and sands are deposited by wind
and water to provide a parent material for s011 development.
Scouring by ice and water during spring breakup and fall
freezeup,and by hi gh water during summer floods accounts
for much of the vegetation dynamics in the floodplain.
Willow and balsam poplar are common early successional
(pi oneer)speci es on the Susi tna Ri ver fl oodpl ai n.They
become established on the most recently deposited river
bars.As the pioneer communities mature,balsam poplar
becomes dominant.The oldest,most stable areas are usually
covered with mixed conifer-deciduous (birch-spruce)forest.
(i)Early Successional Stands
Early successional communities accounted for 5 to 10
percent of vegetated land on the floodplain.They
were usually domi nated by horsetai 1 and/or Drummond
mountain-avens in the ground layer and balsam poplar
and/or willow in the shrub layer.Characteristi-
cally,these communities had little total vegetation
cover and greater than 50 percent bare ground (Table
E.3.73).Plant species in these types generally had
rhizomes,or horizontal underground stems,which
could extend for many meters and were effective in
binding loose sand and silt.Avens was important in
stabilizing gravelly sites.Early successional
stands may be correl ated with low wi 11 ow or mi xed
shrub and tall shrub vegetation types.
In most stands,balsam poplar and wi 11 ow occu r red at
greater densities than other woody species,but alder
had a relatively rapid growth rate and began to over-
top willow and bal sam popl ar withi n two or three
years after its establ i shment.
Floodplain balsam poplar and willow stands may last
up to ten years from the time of the last major dis-
turbance.Aging of these stands is difficult because
floods frequently bury several years'plant growth in
silt,and new growth is present above the silt.This
cycle may be repeated a number of times before vege-
tation succession advances to a later stage.
(ii)Mid-Successional Stands
Deposit;on of sands and sil ts that rai se the el eva-
tion of sites above the level of frequent flooding is
necessary for transition of early successional vege-
tation to mid-successional stages.Mid-successional
E-3-215
3 -BOTANICAL RESOURCES
types accounted for about one-fifth of vegetated land
surveyed in the Susitna floodplain.Thinleaf alder,
or balsam poplar that had developed into tall shrubs
or immature trees,domi nated these stands.Mi d-
successional stands include the open ann closed tall
shrub and balsam poplar forests of Viereck and
Dyrness (1980).The alder type was the first phase
and appeared to persi st from 10 to 25 years after
stabilization.Balsam poplar appeared to dominate 25
to 55 years after stabilization,but stands of this
type were much 1ess common than the younger
alder-dominated stands.As noted earlier,alder
overtops bal sam popl ar duri ng the transiti on from
early-to mid-successional stages.However,after
about 20 years,the balsam poplar that remains
rapidly increases in height,thereby overshadowing
the alder and developing into the immature balsam
poplar phase of the mid-successional stage.
In both alder and balsam poplar stands,there was
essentially no bare ground.As balsam poplar assumes
greater dominance,its density and that of thinleaf
alder and feltleaf willow decline from that found in
the earlier alder stands,since the balsam poplar
trees become larger;but Sitka alder,prickly rose,
and highbush cranberry increase in density (Tabl e
E.3.74 and E.3.75).
(iii)Late Successional Stands
As the balsam poplar stands of mid-succession mature,
whi te spruce may appear in the canopy.Mature bal sam
popl ar stands probably are establ i shed by about 75
years after stabilization and live for about 30 more
years.Eventually,the large balsam poplars die,
1 eavi ng space for development of more bal sam popl ar
or spruce and birch,if no disturbances interrupt the
process.The correspondi ng vegetat i on types of the
late successional stands are balsam poplar forest and
mi xed coni fer-deci duous forest.Factors whi ch cause
development of the bi rch-spruce stands or alterna-
tively promote continuation of the balsam poplar are
not understood.
Mature and decadent (gradually dying)balsam poplar
stands were found on 25 to 40 percent of the vege-
tated floodplain;mixed stands of birch and spruce
occupied 23 to 32 percent of the area.Mature and
decadent balsam poplar stands collectively averaged
90 percent total vegetation cover.Birch-spruce
E-3-216
-
-
3 -BOTANICAL RESOURCES
communities contained 12 percent cover of white
spruce in the overstory (Table E.3.76).
Birch-spruce forest types had the greatest variation
in stand structure of the vegetat i on types found on
the fl oodpl ai n.There is some evi dence that these
stands are self-perpetuating.Upon overmaturity,the
bi rch overstory tends to fall,making the spruce more
susceptible to wind-throw and thereby allowing a
shrubby paper bi rch-a 1der-hi ghbush cranberry-pri ck ly
rose community to develop.The shrub communi ty then
progress,es to the bi rch-spruce forest stage.
(d)Talkeetna to Cook Inlet
Vegetati on in the fl oodpl ai n downstream from Ta O
\keetna had a
simi 1 ar successi onal sequence to that upstream from
Tal keetna.It consisted primarily of bottomland spruce-
hardwood fore.sots (Commonwealth Assoc.1982).The i sl ands
and river bars were somewhat more stable than those upstream
from Talkeetna because of the width of the floodplain,which
reduces ice jam damage and the severity of fl oodi ng.Thi s
i ncreasei n stabi 1i ty correspondi ngly increases the average
age and successional stage of the vegetation present in the
fl oodpl ai n.
Separate mapping of this area was not undertaken.
(e)Transmission Corridors
-
-
(i )Healy to Fairbanks
The classification system used to map the Healy-to-
Fairbanks transmission corridor (Figures E.3.48
through E.3.50)was the same as that used for the
Watana and Gold Creek watersheds (see Viereck and
Dyrness 1980).The corri dor crosses three di st i nct
physi ographi cally and phytosoci 01 ogi cally di sti nct
sections:Healy to Nenana River,Tanana Flats
(Nenana River to Tanana River),and Tanana River to
Fairbanks.Forest types accounted for almost 78
percent of the 274,000 acres (111,000 ha)of the
corridor,with open forest types being dominant
(Table E.3.77).Open spruce covered 28 percent of
the area,open deci duous 11 percent,and open mi xed
conifer-deciduous 11 percent.
The Healy-to-Nenana River section includes a dis-
sected plateau on the west side,a relatively flat
area in the middle,and the Parks Highway and Nenana
E-3-217
3 -BOTANICAL RESOURCES
River to the east.Vegetation along the ridges lead-
i ng from the pl ateau is predomi nantly open coni fer
(spruce),open mixed conifer-deciduous,and open
deciduous forest.The flat area is predominantly low
shrub wi th sedge-grass and open and closed coni fer
types.Most of the spruce trees are relatively
short,except along the streams.
The Tanana Fl ats area extends from just beyond the
Nenana River crossing to the Tanana River.This
section has a mosaic of wet vegetation types (dis-
cussed further in Section 3.2.3)which include open
spruce stands wi th 1arch,low shrub,and wet sedge-
grass.The distribution of many vegetation types
appears to be a consequence of 01 d stream meanders
and drainage patterns.Some patches of deciduous
forest occur.Dry streambeds have stringers of other
vegetation,such as low shrub,along them.
The section from the Tanana River to Fairbanks passes
through rolling hills covered predominantly with open
deci duous forest.Small areas of spruce are 1ess
common than in the Tanana Fl ats secti on.The mi xed
woodl and patches in thi s secti on are generally cut-
over areas.Many of the closed spruce areas produce
very short shrub-like trees.
Most coni ferous forest between the Tanana Ri ver and
Fairbanks contain only spruce;few have larch.About
half the areas in the Tanana Fl ats secti on contain
larch as well.Spruce (presumably black spruce)
occu rs in low,poorly drai ned areas.Spruce in
better-drained locations may be either black or white
spruce.The black spruce-larch type,confined in
Alaska to the interior,is generally found only on
wet 1owl and si tes with shall ow permafrost (Vi ereck
and Dyrness 1980).
(ii)Willow to Cook Inlet
The Willow-Cook Inlet transmission corridor passes
through three pri nci pa 1 kinds of pl ant communiti es--
(1)closed birch and mixed conifer-deciduous forests,
(2)wet sedge-grass marshes,and (3)open and closed
spruce stands (Table E.3.78 and Figures E.3.51 and
E.3.52).
The Willow-Cook Inlet corridor includes approximately
95,000 acres (39,000 ha)(Table E.3.78).It passes
through relatively flat terrain that is 67 percent
E-3-218
-
-
.....
3 -BOTANICAL RESOURCES
forested,predomi nantly wi th conifer-dec i duous
forests.Approximately 24 percent of the area is wet
sedge-grass marsh,discussed further in Section
3.2.3.
Closed conifer-deciduous forest is the predominant
vegetation type,covering 29 percent of the total
area.These forests contain birch,white spruce,and
bal sam popl ar trees.B-j rch is the predominant
deciduous species.Many sites have developed either
a woodl and/shrub 1and or woodl and/grassl and aspect.
In the vicinity of Willow,localized stands of balsam
popl ar are associ ated with the acti ve ri ver
fl oodpl ai n.
Wet sedge-grass marsh is the second most common vege-
tation type in this area (24 percent cover).This
type has an extensive distribution and is associated
with diverse networks of ponds,lakes,and meandering
streams.These areas support little other vegetation
except for scattered islands of black spruce and low
shrubs on drier sites.They are discussed further in
Section 3.2.3.
White spruce,common in most of interior Alaska,is
less common in this part of the Susitna Valley.How-
ever,most closed and open spruce stands (8 and 9
percent cover,respectively)in areas dominated by
mixed conifer-deciduous forest are probably white
spruce.Spruce stands skirting wet sedge-grass or
low shrub areas may be white or black spruce or mix-
tures of the two.Most woodl and spruce stands are
bl ack spruce.
(iii)Willow to Healy
The Willow-to-Healy intertie corridor is covered by
interior forests,muskeg,shrub communities,and
tundra.White spruce and paper bi rch domi nate the
dri er forested landscapes;bl ack spruce is prima rily
located on poorly drained sites.Additionally,bal-
sam popl ar and white spruce develop on the flood-
pl ai ns.Wi thi n or adjacent to these areas,about
thirty species of willow and several species of alder
occur in the understory or in thickets with little or
no overstory.
The Southern two-thirds of this corridor contain
forested areas;the northern portion consists mainly
of open woodland,shrubland,and tundra.The
E-3-2l9
3 -BOTANICAL RESOURCES
corridor contains fewer glaciers and ice fields than
is common in similar sized areas in the region
(Commonweal th Assoc.1982).Upl and and 1owl and
spruce-hardwood forest together cover nearly three
quarters (71 percent)of the total area withi n the
Willow-to-Healy transmission corridor.Upland
spruce-hardwood forest stands cover 2888 acres (1169
ha)and 1owl and spruce-hardwood forest stands cover
1503 acres (608 ha).Shrublands are the third most
predominant cover type (nearly 12 percent)and occupy
713 acres (290 ha).Vegetation types within the
intertie corridor t their areal extent t and percent
toal area covered are presented in Table E.3.79
(modified from Commonwealth Assoc.1982).
(iv)Dams to Intertie
Vegetati on types crossed by the proposed centerl i ne
of the transmission corridor from the Watana and
Devil Canyon damsites to the intertie junction are
shown at a scale of 1:63 t 360 in Figures E.3.39 and
E.3.40.Nearly one-half (49 percent)of the total
area (938 acres t 380 ha)within the Watana-to-Devil
Canyon section of the transmission corridor is
shrubland.Predominant vegetation types crossed
include closed tall shrubland (128 acres;52 ha)t low
willow shrubland (218 acres t 88 ha)t sedge-grass
tundra (117 acres;47 ha),sedge-shrub tundra (119
.acres,48 ha),and mat and cushion tundra (126 acres,
51 ha).The Devil Canyon-to-intertie section of the
transmission corridor covers a total of 325 acres
(132 ha)t 277 acres (112 ha)of which is closed mixed
forest.A small amount of wet sedge-grass tundra (28
acres t 11 ha)also exi sts within the corridor.The
areal extent and percent total area for·coverage by
each vegetation type within the Watana-to-Devil
Canyon and Devil Canyon-to-intertie sections of the
transmission corridor are presented in Table E.3.80.
3.2.3 -Wetlands
Wetlands are lands where saturation with water is the dominant
factor determining the nature of soil development and the types
of plant and animal communities living in the soil and on its
surface.These areas are characterized by soil or substrate that
is at 1east peri odi cally saturated with or covered by water
E-3-220
(,.--
-
3 -BOTANICAL RESOURCES
(Cowardi n et al.1979).Because wetl ands are recogni zed to have
important resource values,they are protected by state and
federal regulations (Alaska Office of Coastal Management 1982).
Examination of potential project impacts to wetlands,and how
such impacts can be avoided,is mandated by Executive Orders
11988, 11990,and 11991,and by Secti on 404 of the Cl ean Water
Act as amended (86 Stat.884,USC 1344).
The classification system of Cowardinet al.(1979)recently
adopted by the USFWS (1980b)defi nes wetl ands as havi ng one or
more of the following characteristics:(1)at least periodical-
ly,the land supports predominately hydrophytes;(2)the sub-
strate is predominately undrained hydric soil;or (3)the sub-
strate is nonsoi 1 and is saturated wi th water or covered by
shallow water'at some time duri ng the growi ng season of each
year.
Secti on 404 of the Cl ean Water Act extends permi t authority to
the U.S.Army Corps of Engineers (COE)for all waters of the
United States,including wetlands.The COEls reguations (33 CRF
320-330)defi ne "we tl ands II to mean "those areas that are inun-
dated or saturated by surface or ground water at a frequency and
duration to support,and that under normal circumstances do sup-
port,a prevalence of vegetation typically adapted for life in
saturated soi 1 condi ti ons.Wetl ands generally i ncl ude swamps,
marshes,bogs and similar areas."
In Exhibit E,Chapter 3,the term "we tland"is used in three
different ways.In discussions of impacts and mitigation invol-
vi ngwetl ands in general,the term is used to denote areas at
1 east pa rtly characterized by hyd rophil ic vegetat i on and the pre-
sence of standing water or sheet flows.In addition,wetlands
mapping of the impoundment zones,adjoining borrow and
construction areas,and access corridors by McKendrick et al.
(1982)uses wetland types defined by Cowardin et al.(1979)based
on corre1at i on wi t h Vi ereck and IDyrness (1980)vegetat i on types
mapped to classification Level III (Section 3.2.2(a)).Finally,
two vegetation types characteristic of wet or poorly drained
areas,wet sedge-grass and bl ack spruce forest,were mapped for
the Healy-to-Fairbanks and Willow-to-Anchorage transmission
corri dors by TES and Acres Arne ri can Incorporated (1982,modi fi ed
from McKendri ck et al.1982).Only wetl and types mapped as
defined by Cowardin et al.(1979)are descr"ibed in quantitative
terms or shown as fiures herein.
(a)Methods
Wetland vegetation types were mapped by McKendrick et al.
(1982)at a scale of 1:24,000 from the Oshetna River to the
Devil Canyon damsite,using the system of Cowardin et al.
(1979)(Figures E.3.66 through E.3.73).This mapping
E-3-22l
3 -BOTANICAL RESOURCES
covered the impoundment areas and adjoining construction and
borrow areas.The access corridors were mapped at a scale
of 1:63,360 (Figures E.3.47 through E.3.47).
Wetland maps were produced by first correlating the vegeta-
tion types from Viereck and Dyrness (1980)with cover
designations from the wetlands classification of Cowardin et
a1.(1979)(Table E.3.81).Corresponding wetlands
categori es were then superimposed over the vegetati on maps
of the 1 :24,000 scale prepared by McKendrick et a1.(1982).
The presence of steep slope and 1i ke1y good drainage was
interpreted to rule out classification as wetland.Lakes,
ponds,rivers,and streams were not specifically
classified.
Because the system of Cowardin et a1.(1979)requires addi-
tional data on hydric soils and periodic ambient water
conditions to characterize wetlands completely,the mapping
is liberal and indicates areas which potentially qualify as
wet1 ands und.er that system.Port;ons of these areas may
be e1 imi nated by further consi derati ons of soil and water
conditions.Data on soils and water will be collected in
the future during detailed construction planning and used to
refine the identification of wetland areas in accordance
wi th the requi rements of Secti on 404 of the C1 ean Water
Act.
Aquatic vegetation of the Watana and Gold Creek watersheds
was exami ned duri ng August 1982.In order to obtai n si te-
specific information on aquatic plant species,24 selected
ponds and 1akes and thei r adjacent upl ands were surveyed on
foot,from Devi 1 Canyon (RM 152)to the conf1 uence of the
Susitna and Oshetna Rivers (RM 233)(Figure E.3.75).
During the surveys,species composition,dominance,and
total cover (relative to the amount of water)were esti-
mated.Elevation,estimated rooting depth,and width of
surrounding wetland area were recorded.Surrounding wetland
was limited by definition to the Lacustrine-Limnetic-
Emergent Wet1 and-Vascu1 ar wetl and c1 ass of Cowa rdi n et ale
(1979).Many remaining ponds and lakes were examined by
helicopter overflights.
E-3-222
3 -BOTANICAL RESOURCES
....,
(b)General Description
Wetlands within the Susitna project area include riparian
zones.ponds and lakes on upland plateaus,and wet tundra.
Thesewe~lands support waterfowl in the summer (23.8
adults/km censused in July 1981).and are al so used by
migratory birds in spring and fall.Although the density
and diversity of bird species are lower for the Susitna
project area than for many other areas of Alaska (Kessel et
al.1982a),scoters.terns.scaup.mallards,American
wi dge:ons,swans.and other waterfowl were found duri ng
wetland surveys (Section 4.2.3[6]).
Wetland areas in the vicinity of the project include upper
Brushkana Creek and Tsusena Creek,the area between lower
Deadman Creek and Tsusena Creek.the Fog Lakes area,the
Stephan Lake area.Swi mmi ng Bear Lake,and Jack Long Creek
(Figure E.3.36).There are large number of lakes in the
extensive flats of the Watana watershed,such as those in
the Lake Louise area.Vegetation types indicating potential
wetlands within the Watana and Devil Canyon impoundment
areas and wi thi n borrow si tes proposed for dam constructi on
are shown in Fi gures E.3.66 through E.3.73.
As illustrated in Table E.3.81,the wetlands classification
of Cowardin et al.(1979)may be used as a second level of
classification applied to the vegetation types previously
discussed (Section 3.2.2).Areal extent of vegetation types
in the Watana and Gold Creek watersheds are listed in Tables
E.3.51 and E.3.52.The most common vegetation type
occurring in this area was the low shrub type (32 percent
total cover).Thi s vegetati on type corresponds to the
potenti al pal ustri ne scrub-shrub wetl and type of the
Cowardin system (1979).The areal extent listed indicates
the potential areal extent of palustrine scrub-shrub wetland
type.Woodland spruce forests cover nearly 12 percent of
the Watanaand Gal d Creek watersheds and i ncl ude a porti on
of the potential palustrine forested areas.Wet sedge-grass
tundra covers less than 1 percent of the total area.Lakes
and rivers comprised a total of 21.4 percent of the entire
Watana and Gold Creek watersheds.
The areal extents of di fferent potential wetl and vegetation
types whi ch wi 11 be affected by the Watana and Devi 1 Canyon
developments are indicated in Table E.3.82.The estimates
of total pal ustri ne wetl and areas shown in thi s tabl e are
extremely liberal,because tl:le wetlands were highly
integrated with non-wetlands,and supporting soil and water
data were not used to refine the areas mapped.As described
E-3-223
3 -BOTANICAL RESOURCES
below additional wetland mapping is in progress.Therefore,
the values shown in Table E.3.82 should be considered
prel imi nary.
Wet sedge-gress and potential wet spruce areas occur within
the Hea ly-to-Fa i rbanks and Wi 11 ow-to-Anchorage transmi ss ion
corridor study areas.As discussed further in Section
3.4.2(c)the centerl ines will be further eval uated in the
fiel d and adjusted to avoid wetl and areas as determi ned by
the analysis of vegetation,soils,and water data.
Aquatic species identified in the Watana and Gold Creek
watersheds,percent cover of aquati c vegetat i on,and
surrounding wetland width are listed by site in Table
E.3.70.Wetland sites sampled ranged in elevation from 1700
feet to 3000 feet (518 m to 914 m).A summary of the domi-
nant aquatic species and factors which may influence their
location in and around many of the waterbodies in the Watana
and Gold Creek watersheds is presented in Figure E.3.76 (see
Section 3.2.2[b][v]Aquatic Vegetation for further discus-
sion).
Additional mapping of wetlands is being conducted (Section
3.2.2[a]);preliminary maps and estimates of wetland areal
coverage will be available in June 1983.Maps are being
prepared at a scale of 1:24,000,using low-altitude color
infrared and true-color photography taken in 1980-1982.The
herbaceous vegetation type of Viereck et ale (1982)is being
mapped to Level IV,and forest and shrub types are being
mapped to at least Level IV with wetland modifiers (modi-
fiers indicate which areas are subject to flooding).The
area being mapped includes the impoundment and dam areas,
borrow sites,construction camps and village,and access
corridors.
3.3 -Impacts
Impacts of the Susitna Hydroelectric Project on vegetation are of two
general kinds --(1)loss of all vegetative cover;and (2)change in
the nature of vegetatative cover (i.e.,alterations in plant community
types).The first kind of impact is considered adverse;while the
second kind may be considered adverse or beneficial depending upon its
effect on wildlife.The following discussions treat both kinds of
impact.
E-3-224
,.,..
,~,
3 -BOTANICAL RESOURCES
3.3.1 -Watana Development
The Watana development i ncl udes areas affected by the Watana
impoundment zone ~borrow s ites ~dam and spill way ~const ructi on
camp and airport~and permanent village.Impacts of access roads
and transmissions corridors are discussed separately.
(a)Construction
(i)Vegetation Removal
Construction of the Watana development will result in
the direct removal of vegetation within an area of
approximately 40~974 acres (16~582 ha)covering a
range of el evat ions from approx imatel y 1400 to 2400
feet (430 to 7~9 m).Within the dam~spillway~and
impoundment areas~about 36~642 acres (l4~329 ha)of
vegetation will be removed by construction and clear-
ing operation.Included are 26~730 acres (10~818 ha)
of forest that is composed primarily of large stands
of both woodland and open black and white spruce~as
well as some open mixed forest types.The camp~
village~airstrip~and borrow areas will remove an
additional 4300 acres (1742 ha)~most of which is
shrubl and or bl ack spruce forest.Spoil areas will
alter vegetation between 1400 and 1600 feet (430 and
488 m).All vegetation removed during construction
of the Watana dam ~reservoi r ~and ancill ary support
facilities will represent about 1 percent of the
total vegetation of the Watana and Gold Creek water-
sheds (defined in Section 3.2.2;see Figure E.3.36).
Table E.3.83 1 ists the area of each vegetation type
to be directly removed by the Watana development~and
compares each value to the total area of that vegeta-
tion type within the Watana and Gold Creek water-
sheds.Approximatel y one-thi rd (34 percent)of the
open bi rch stands,and all 1arge closed bi rch stands
in the Watana and Gold Creek watersheds will be
removed by the Watana development.The relative loss
of other types is small when compared to their avail-
ability in the basin.For example,only 3.4 percent
of forested areas~0.1 percent of tundra types,and
0.4 percent of shrubland cover types will be directly
removed by the development.
E-3-225
3 -BOTANICAL RESOURCES
(ii)Vegetation Loss by Erosion
Erosion is a persistent problem at dam construction
sites in northern latitudes (Baxter 1977,Baxter and
Glaude 1980).Erosion following the clearing of
vegetation may be promoted by the following:
-Destabil ization of till;
-B10wdown of trees near cleared areas;
-Thawing of permafrost;
-Desiccation of exposed soils;and
-Changes in drainage patterns.
Slope stability studies by Acres American (1982)
indicate that areas particularly vulnerable to vege-
tation loss through erosional effects include side
slopes of the canyon from the south abutment of the
Watana damsite (RM 184)to Vee Canyon (RM 225),along
Watana Cree k (RM 194),and from the Watana reservoi r
headwaters to the Oshetna-Goose Creek area (RM 243 -
233).Approximately 1379 acres (558 hal above the
impoundment shoreline were shown as potentially
unstable and thus subject to vegetation loss.
(iii)Vegetation Damage by Wind and Dust
B10wdown of trees is a recognized problem in cleared
areas (Todd 1982).Near reservoi rs,it is promoted
by increased wi nds due to a greater fetch as areas
are cleared (Baxter and Glaude 1980,Brown 1972).
Since northeasterly winds predominate in the project
area most of the year,the greatest b10wdown poten-
tial is in the woodland black spruce stands on the
south side of the Watana damsite.The shallow
rooting depth typical of black spruce 12 inches
(35 cm)indicates that this vegetation type is
subject to b10wdown (McKendric1e 1982 pers.comm).
Wind-generated dust is expected to occur during con-
struction activities,particularly during and follow-
ing clearing of the impoundment and borrow areas.
Increased wind fetch is expected to result from
clearing.Accumulations of thick dust on vegetation
can potenti ally retard snov.melt (Drake 1981).The
vegetati on types whi ch will be affected by dust in
the Watana area i ncl ude wood1 and and open b1 ack and
white spruce,mixed forest types and shrubl and.The
direct effect of dust on plants varies with plant
species and the chemical composition of dust.For
example,densities of cottongrass (Eriophorum spp.)
are likely to increase,but stiff c1ubmoss,sphagnum
E-3-226
--I
3 -BOTANICAL RESOURCES
!I""",
-
-
(i v)
(v)
(vi)
(vi i )
moss,and some fructicose 1 tchens may decrease in
abundance when exposed to dust (CRREL 1980).Mosses
and 1 i chens are important components of the ground
cover in open and woodla,nd spruce and closed mat and
cushion tundra stands (see Section 3.2.2).
Effects of Altered Drainage
Local al terati on of drai nage patterns and surface
water regimes may result from clearing,ditching,and
other construction activities.Blocking drainage
patterns may cause waterl oggi ng of soil s,thermal and
hydraulic erosion,and shifts of surface flow to
adj acent dra i nages (CRREL 1980).Resulti ng changes
in surface water regimes will cause plant communities
to shift accordingly.The time required for these
changes to occur,and the extent of the change,will
depend on the extent of hydrologic alterations and on
plant successional dynamics (Neil and and Viereck
1977)•
Effects of Change in Albedo
Cleared soils usually absorb more solar radiation
than do vegetated soils and consequently thaw sooner
in spri ng and deeper over the summer.Conversely,
with less insulation soils freeze earlier and deeper
in the winter.Resulting changes in surface
hydrology will cause plant communities to change.
Indirect Conseguences of Vegetation Removal
Methods of vegetation removal may have indirect
impacts on other vegetation.Spruce budworm disease,
which occurs in areas adjacent to the Susitna water-
shed (Hegg 1970),may be more likely to invade the
area if spruce trees are cut but not removed or
burned.Clearing may also enable other insects and
decay organisms to increase in abundance (Kimmey and
Stevenson 19~7).
Effects of Increased Fires
The increased numbers of people in the area during
the construction period may cause increased inci-
dences of fi res.Fi re has been a natural factor
shaping plant communities in the area,so increased
fires will cause changes in plant communities similar
to those that can already be observed there.
E-3-227
3 -BOTANICAL RESOURCES
Because successional
related fires are more
d ur i ng the ope rat ions
Section 3.3.1(b).
(b)Filling and Operation
patterns foll owi ng proj ect-
likely to manifest themselves
phase,they are discussed in
,~,...,--.-
The Watana facility is scheduled to begin filling in 1990.
Some construction-related impacts such as fugitive dust will
diminish,but other problems such as erosion will continue.
The most conspicuous filling and operation-related changes
in vegetation will be downstream as a result of streamflow
regulation,but less drastic changes may be caused by micro-
and mesoclimatic changes,increased fire incidence,and
increased off-road vehicle (ORV)use.In many instances,
vegetati on wi 11 respond to these di sturbances through char-
acteristic successional recovery patterns.The following
subsections describe fill ing and operation-rel ated changes
and the successional patterns of plant communities as they
recover from development-induced change.
(i)Vegetation Succession Following Removal
On sites where vegetation has been removed,natural
plant succession will occur unless prevented by inun-
dation or facility maintenance.Successional pat-
terns expected in forests,shrublands,and tundra are
discussed below.
-Forest Areas and Shrubland
Within forest and shrubland areas,newly cleared
sites with largely intact mineral and organic soils
wi 11 rapi dl y revegetate with pl ants native to the
original community.Herbs,shrubs,and deciduous
trees wi 11 resprout,and some herbs and shrubs will
regenerate from buri ed seed (Nei 1 and and Vi ereck
1977,VanCl eve and Vi ereck 1981,Conn and Delapp
1982a,b).
In interior Alaska,characteristic early succes-
sional herbs and shrubs are bluejoint reedgrass,
field horsetail,prickly rose,bluebell,bunch-
berry,northern bedstraw,labrador tea,Ameri can
twinflower,goosefoot,pale corydalis,American
dragonhead,fi reweed,crazyweed,and rough
cinquefoil.Early successional trees are willow,
aspen,and poplar.
E-3-228
-
-
-
.....
-
3 -BOTANICAL RESOURCES
From 6 to 25 years after cl eari ng,willow and/or
alder will typically dominate areas that were
originally bl ack spruce forest or shrubl and (see
reviews of forest succession by Neiland and Viereck
1977,Vanel eve and Vi ereck 1981).McKendri ck et
ale (1982)found that typical heights for willow
and alder between 3 to 6 years old were 15 inches
(60 cm)and 68 inches (170 cm),respectively.Soon
thereafter a tree canopy of young bl ack spruce,
willow,and alder will develop.Dense stands of
spruce with well-developed moss and 1 ichen compo-
nents will not develop for 50 to 100 years.Mature
black spruce trees in typical 100 year old stands
usually do not exceed 45 feet (15 m)in height.
-Tundra
Cl eari ng of tundra and concurrent removal of top-
soil will,except in certain rocky alpine sites,
typically resul t in higher soil temperatures and,
if permafrost is present,a deeper thaw (Bliss and
Wein 1972,Hernandez 1973,Gersper and Chall inor
1975,Chapin and Shaver 1981).Either of these
conditions may lead to the development of a dif-
ferent plant community from that originally present
and possibly a very long restoration period.One
to several centuries may be requi red for recovery
from disturbance where the topsoil is lost (Brown
et ale 1978).But if topsoil is retained,recovery
to the same community type can be rapid.The top-
soils contain most of the available nutrients,
rhizomes,and seeds required for rapid recoloniza-
tion (see discussion by Chapin and VanCleve 1978).
Although natural successional trends of tundra are
fa r 1ess pred i ctab le than for forested areas,the
following sequence is likely to occur.The first
vegetation types to reestablish in moist or wet
tundra (with the organic layer retained)are likely
to be cottongrass species and,if buried seed is
present,sedges on wet sites.Grasses may predomi-
nate on drier sites (see Chapin and Chapin 1980,
Chapin and Shaver 1981,Gartner 1982).Within 5 to
10 years after normal revegetation begins,at least
50 percent and often 100 percent of v~getation
cover recurs on sites on which the original organic
layer was retained.Native woody and herbaceous
species characteristic of adjacent areas will also
begin to invade within 10 years;likely species in
E-3-229
3 -BOTANICAL RESOURCES
the project area incl ude willows,bog bl ueberry,
mountain cranberry,northern Labrador tea,shrubby
cinquefoil,prickly rose,field oxytrope,lupine,
green al der,and dwarf and resi n bi rch.Reestab-
lishment of normal densities,however,may require
several decades.
(ii)Effects of Erosion and Deposition
If the drawdown zone of theWatana impoundment is
typical of that of other northern reservoirs,it will
remain unstable until bedrock or gravel/cobble/
boul der substrates are exposed.The drawdown zone
will remain essentially unvegetated.This will
resul tin an unvegetated area between the el evat ions
of 2095 feet and 2185 feet (639 m and 666 m)along
the reservoir.(Range equals 90 feet [27 m]as shown
by the rul e curve for Watana Reservoi r,Exhi bit B,
Figure B.53).Shoreline recession is likely,with
consequent loss of vegetation (Baxter and Glaude
1980).Except during a series of drought years,
vegetation is not expected to invade the drawdown
zone,and no effects on vegetation from ice shelving
are anticipated.Although some of the evolving
shoreline above the drawdown zone will be readily
colonized by early seral stages such as grasses and
herbaceous species,stabilization of this upper
shoreline may require 30 years or more (Newbury and
Malaher 1972).
After the reservoi r is fi 11 ed,the water wi 11 warm
adjacent hillsides,causing permafrost to melt and
sl ides to occur.On the south side of the Watana
impoundment,the permafrost layer is 200 to 300 feet
(60 to 90 m)thick and is within 1.8°F (l0e)of
thawi ng.51 ides and 1and sl umpages are therefore
likely on the south side of the reservoir.If these
sl ides are small and the organic soil layers have not
been lost,encroachment by rhizomatous species may
enable rapid recolonization.If large slides occur,
a full cycl e of forest successi on on mel ted perma-
frost may ensue,1eading to bl ack spruce and bog
vegetation over 100 to 200 years.
Following beach (mudflat)development,flooding of
upland areas may occasionally occur as a result of
water displacement from slumpage (Kerr 1973)and
during high flows.This occasional flooding of
adjacent areas will likely stimulate new vegetation
growth.Propagat i on of del tas into the reservoi r at
E-3-230
....
-
-
-
3 -BOTANICAL RESOURCES
a number of creek tri butary mouths is 1i kel y si nce
depositi on wi 11 occur when fast creel<currents empty
into slow-moving reservoir water.These deltas may
eventually be vegetated in the same manner as down-
stream floodplain areas (see discussion below).
(iii)Effects of Regulated Flows
A mosaic of plant communities in various stages of
floodplain succession is found in the floodplain of
the Susitna River.This diversity is the result of
processes of vegetative recession;the replacement of
an establ ished plant community with a younger
community.Vegetative recession results from changes
in river morphology,which is controlled in the
Susitna River floodplain primarily by ice processes
and flood i ng events.These processes are effecti ve
mainly during river freezeup and breakup.To a
lesser degree,vegetative recession also results from
bank erosion and deposition of bed material through-
out the open water period,but this is a minor,
localized process in the Susitna River floodplain.
Figure E.3.78 illustrates patterns of vegetation
succession.
The effects of regul ated flows on vegetati on at a
particular location will vary considerably with
channel morphology and the di stance downstream from
the Watana dam.Potential impacts on floodplain
vegetation will be discussed separately for the river
reaches between Watana and Devil Canyon,Devil Canyon
to Talkeetna,Talkeetna to the Yentna River,and from
there to Cook Inlet.Additional information on
channel morphology and changes in the hydrologic
regime can be found in Chapter 2,Sections 2.1 and
3.2.3.
-Watana to Devil Canyon
(RM 184 to RM 152)
This reach of the river is mostly a single channel
with steep armored banks and bedrock outcroppi ngs.
The two dominant processes presently controlling
vegetative recession are ice scouring at river
freezeup and at breakup.
During river freezeup,the steep gradient of the
river stretch restricts ice formation to the
borders of the river channel in most areas (see
Chapter 2).Growt h of border ice and ice in the
center of the channel of slower reaches results in
increased stage.Buoyant forces on the border ice
E-3-23l
3 -BOTANICAL RESOURCES
resulting from increased staging cause scouring of
attached vegetation as the ice fractures,rises,
and disintegrates.In addition,ice blockage in
the channel can resu1 t in ice scouri ng of vegeta-
tion higher on the banks and islands and can also
cause the river to overflow into side channels
where additional scouring of bed materials and
vegetation occurs.
The effects of river breakup on vegetation are
greatest when breakup occurs rapidly before exten-
sive in-place melting and deterioration (rotting)
occurs and in association with high spring flows.
Ice jamming in spring at constricted points has
effects similar to those occurring at freezeup but
can have much more dramati c local effects due to
the typically higher discharges which occur during
breakup.
The increased temperatures of the water rel eased
from Watana in winter will preclude the formation
of an ice cover in this reach.In addition,the
mean annual flood will be reduced by 75 percent to
12,000 cfs.These changes will result in vegeta-
tion encroachment toward the main channel,the
establishment of vegetation in overflow channels
and new1 y-exposed areas with adequate soil s,and
the gradual succession of existing and new1y-
established vegetation stands along the bank and on
i sl ands to mat ure pop1 ar and white spruce forest.
Although the rate of vegetative recession may be
reduced by as much as 90 percent,the amount of
area a ffected will be 1imited by the steep ban ks
and poor substrates found throughout most of thi s
reach.
The open-water area in wi nter may promote ice fog
conditions and rime ice formation on vegetation,
particularly at the dam outflow.Buildup of rime
ice may result in loads sufficient to break twigs.
Birch trees may be particularly susceptible to this
damage because of thei r many small branches.
Sap1 ing tree stands heavily damaged by ice have
been found to produce more brush,whereas ice
damage in mixed oak tree stands resulted in loss of
understory saplings and low tree branches (Wood et
ala 1975).
E-3-232
~,
r
.-
-.
.-
-
-
-
-
3 -BOTANICAL RESOURCES
-Devil Canyon to Tal keetna
RM 152 to RM 97}
The Susitna River in this reach comprises alter-
nately single channel and spl it channel configura-
tions •.The channel is armored with boulders and
cobbles and alignment has changed little since
1951.A comparison of aerial photographs taken in
1951 wi th those taken in 1980 showed vegetati ve
recess i on resulti ng from shi fts in the outermost
banks of the river.The photography did not allow
an estimation of the actual areas affected.The
rate of .~egetative recession is controlled
primarily by ice processes during freezeup and
breakup,with summer flooding events having a
lesser but important effect.R&M (1982)listed
severa 1 1ocat ion sin thi s reac h where chan ne 1 con-
strictions cause recurrent ice jamming during
breakup.Vegetation patterns just upstream from
these locations are influenced primarily by ice
scouri ng duri ng breakup,but along the maj ority of
this reach ice processes accompanying river freeze-
up appear to have the greatest influence on vegeta-
tive recession.The fact that the vegetation line
at a point 0.5 mi (18 km)upstream from Gold Creek
(RM 136.8)is at the same elevation as ice staging
during freezeup in fall 1980 is evidence of the
influence of ice scouring during breakup in this
reach (T.Lavender 1982 pers.comm.)•
The mean annual flood at Gold Creek will be reduced
from 49,500 cfs to 12,000 cfs by the Watana
project.Ice will still form in this reach,but
the ice front at the end of wi nter is expected to
occur between Portage Creek (RM 149)and Curry (RM
120.5),and its formation there will be delayed by
3 to 4 weeks (see Chapter 2,Section 3.2.3).
Because air temperatures will be lower once ice
formation begins,the ice layer will progress more
rapidly than it does under pre-project conditions.
Regulated winter flows at Gold Creek will be
similar to existing conditions during filling,but
during operation will be at least five times
greater than pre-project winter flows (Chapter 2,
Section 3.2.3).This will result in a 3 to 4 foot
increase in river stage over existing conditions
when an ice cover is present in this reach.During
the early years of the operation phase,this
increased ice staging will scour existing stands of
E-2-233
3 -BOTANICAL RESOURCES
vegetation,thus causing an increase in the width
of the unvegetated channel and a decrease in the
amount of vegetati on found on i sl ands.Because
spring flood stage will be reduced considerably and
because the ice cover will no longer have a greater
tendency to melt in place,ice scouring during
breakup wi 11 no longer be an important factor
causing vegetative recession in this reach.The
area affected by these post-proj ect processes will
be directly related to winter flow releases,which
wi 11 vary between 5,000 -19,300 cfs depending on
downst ream flow requi rements,power demand,reser-
voir operating rule curve,and attenuation of
discharge due to floodplain storage capacity.
-Talkeetna to Yentna River
(RM 97 to RM 28)
There is a dramatic change in the morphology of the
Susitna River from a spl it channel to a braided
channel at the confluence of the Susitna,Chulitna,
and Talkeetna Ri vers.The fl ows contri buted by
each of these rivers at the confluence are 40
percent each for the Chul itna and Sus itna Ri vers,
and 20 percent for the Talkeetna River.
Downstream from Tal keetna,the importance of ice
processes in vegetative recession is reduced,and
large changes in channel position and form pre-
sently occur whenever the ri ver attai ns bankfull
stage.The importance of ice processes in vegeta-
tive recession in this reach is local and depends
on channel morphology.
Upstream from channel constri cti ons,ice processes
during freezeup and breakup may continue to pl ay a
major role in regulating vegetative recession.If
ice processes cause greatly increased stages during
either freezeup or breakup at such a constricted
point,vegetation immediately upstream and/or along
overfl ow channel s may be scoured by water and ice
action.This increased staging at channel con-
stri cti ons may occur even at rel at i vel y low fl ows.
However,because of the localized importance of ice
processes,summer flood events may control vegeta-
tive recession as much as ice processes associated
with freezeup through thei r effect on the rate of
bank erosion and sediment deposition in this reach.
Where the floodplain is wide with braided channels,
there is generally a relatively small increase in
E-3-234
-
-
,F*"'"
-,
-
-
"...,
3 -BOTANICAL RESOURCES
stage when an ice cover is present,and ice proces-
ses have a lesser effect on vegetative recession.
In such areas,numerous islands with mature forest
stands are present.
It is imposs'ible to predict with certainty the
vegetat i on changes that will occur post-project in
this reach.The bankfull flood will have a post-
proj ect recurrence interval of once every 5 to 10
years,as opposed to the present 2-year interval
(R&M 1982).In areas where such floods control the
vegetation,early-successional stands may develop
for about 5 to 10 years before being removed by the
next bankfull flood.In same of these stands,
however,silt deposition or vegetation growfh may
be rapid enough to stabilize the area against
subsequent floods.Increased wi nter flows with
subsequent increases in ice staging may cause other
areas to undergo regular ice scouring during
freezeup.The amount of area supporting mature
stands of vegetation will be directly influenced by
floods and the flow releases from Watana each
winter.
-Yentna River to Cook Inlet
(RM 28 to RM 1))
The Yentna Ri ver contri butes about 40 percent of
the mean annual flow enteri ng Cook Inlet from the
Susitna Ri ver.Between the Yentna confl uence at RM
28 and the beginning of the delta at RM 20 (Figure
E.3.3),the bankfull flows (80 percent of which are
contributed from rivers other than the Susitna 'up_
stream from Tal keetna)are probably the dominant
factor in controlling vegetative recession.The
river begins to branch out into its delta channels
at RM 20.The water surface el evat i on at thi s
point is,approximately 30 feet (9.1m),which 'corre-
sponds to be the 30-foot(9.1-m)tides in Cook
Inl et.
Post-proj ect changes in vegetat i on cannot be pre-
cisely predicted,but should be substantially
mediated by the large flow contribution from the
Yentna River and the tidal influence as far north
,as RM20.As R&M (1982)state,lithe dilution
effect of major and minor tributaries as well as
the balancing of changes by the Sus itna River
system shoul d mask any measurabl e changes that
coul d occur as a resul t of the pr'0j'ect for several
decades.1I
E-3-235
3 -BOTANICAL RESOURCES
(iv)Climatic Changes and Effects on Vegetation
Reservoirs act as a heat source or sink,warming and
cooling less rapidly than the surrounding terrestrial
substrate.These effects may delay the normal spring
warming and fall cooling of adjacent environments and
so affect the phenology and di stri but i on of nearby
vegetati on.Temperature effects most 1 i kel y woul d
not extend beyond 2 miles (3.0 km)of the water mass.
Due to the prevail i I1g northeasterl y wi nds,the area
along the south shore of the reservoir would be most
likely affected.Vegetation types in this area
consist mainly of open and woodl and black spruce,
open mixed forest,and a limited amount of shrubland.
Crowberry,Labrador tea,blueberry,willow,and
mountain cranberry are important components of the
shrub layers of these types and would be the species
to be affected by changes in timing of bud break or
flowering.
Spring air temperatures in the immediate vicinity of
the reservoi r will be cool er on the average than at
present.The cumul ati ve effects of a cool er spri ng
environment on the entire plant community are not
well understood.Phenology studies are now in pro-
gressto determine the pattern of greenup near the
proposed impoundment.Resul ts from 1982 wi 11 be
reported in April 1983.
The Watana impoundment should act as a heat source in
fall,maintaining slightly warmer air temperatures
than normal.The probable effects of this warming on
vegetation cannot be predicted with any certainty.
For example,it is not known how local climatic
changes will affect characteristics of the growing
season.
Another thermal effect of the Watana impoundment will
be its moderation of diurnal changes such that nearby
nighttime temperatures during May and June wi 11 be
higher and daytime temperatures will be lower than
prior to development.Average fall temperatures near
a 1ake of simil ar si ze to the Watana reservoi r were
characterized by a 9.9°f (5.5°C)lower maximum and
4.0°F (2.2°C)higher minimum than temperatures away
from the 1ake (Baxter and Gl aude 1980).The effects
of these thermal changes on the vegetation are,
again,difficult to predict in any quantitative way.
During winter,the development of extensive fog banks
near the Watana impoundment may al so affect
E-3-236
3 -BOTANICAL RESOURCES
vegetation.Fog banks tend to be persistent at
reservoir sites after breakup (Baxter and Glaude
1980),and can resul tin the depositi on of copi ous
~uantities of hoar frost on trees and shrubs.
Buckler (1973)reported that ice crystals 2 to 3 in
(5 to 7 cm)in length were found on vegetation close
,....,to a reservoir when temperatures below -9.4°F(-23°C)
created steam fog.Such buildup of ice may result in
damage to understory or reduction in browse qual ity
or availability (see Section 3.3.1(b)[iiiJ).
--
,....
-
-
(v)Effects of Increased Human Use
During the filling and operation stages of the Watana
facilHy,project personnel and their families will
have an impact on the vegetation of the middle
Susitna bas-in.The most severe human-use impacts
will probably be associated with off-road vehicles
(ORVs)and accidental fires,assuming that no regula-
tion of project personnel is enforced to mitigate
these impacts.Similar but more extensive impacts
are expected from use by the general publ ic and are
discussed in Section 3.3.3 Access.
-Off-Road Vehicles
The effects on vegetat i on of ORV use vari es wi th
season,soi 1 moi sture and depth,the presence or
absence of permafrost,vehicle weight,frequency of
use,and other factors (Chapin and Van Cleve 1978,
Sparrowet al.1978).
The ground layer of vegetation is more susceptible
to damage by ORVs than are other 1ayers.Vegeta-
tion is most susceptible to damage in summer.In
winter,snow and ice layers minimize damage to the
underlying vegetation and organic mat.Dry habi-
tats are relatively immune to damage by ORVs.A
few passes of light-track vehicles over relatively
dry well-drained soils may result in slight compac-
tion of the organic and/or plant layer,a net soil
temperature gai n,and deeper thaw of the acti ve
soil layer.The typical result is minor subsidence
and an influx of ground water.
Tundra and wetlands,especially sites with under-
lying permafrost,are the most vulnerable habitats.
Repetitive off-road traffic or use of heavy ve-
hicles in moist areas is likely to remove vegeta-
tion and also the underlying organic mat.This
E-3-237
3 -BOTANICAL RESOURCES
would cause soil temperature increases,deeper
thaw,subsi dence to 3 feet (1 m)or more,ground-
water input,and severe erosion that may last 5 to
50 years or more (Hok 1969,Rickard 1972,Lawson et
al.1978,Chapin and Shaver 1981).Quagmires may
form as a result of ponding of surface water
(Sparrow et al.1978),or gully formati on may
result.Near the Denal i Hi ghway,Spa rrow et al.
(1978)observed gull ies formed after ORV use as
wide as 20 to 26 feet (6 to 8 m)and up to 10 feet
(3 m)deep,with severe side erosion and cave-ins,
as well as active transport of sed iment downhi 11 •
A similar effect was noted when firel ines were
established on Wickersham Dome,near Fairbanks
(Lotspeich 1979).The above effects will be most
severe where ground ice content is high (Bliss and
Wein 1972).Natural restoration of the organic
layer of tundra soils may require more than a cen-
tury (Chapin and Van Cleve 1978).However,some
grasses,such as bluejoint reedgrass,may be able
to invade mineral substrates rapidly (Gartner
1982).
-Fires
Although the results of tundra fires are extremely
variable,in most cases all signs of the fire have
disappeared after 6 to 8 years.Recovery can take
much longer in areas with abundant 1i chen cover
(Viereck and Schandelmeier 1980).In shrubland and
forest,a variety .of successional patterns might
result from a fire,depending on fire intensity and
burning patterns,vegetation type,soil moisture
and temperature,time of year,and post-fi re
weather patterns (Figure E.3.77).For example,
some willow species,while highly adapted for re-
seeding burned areas,produce seeds that are viable
for only short periods of time in the spring or
fall (Zasada and Vi ereck 1975,Zasada and Densmore
1977)•
Trees and shrubs,including aspen,birch,willow
and alder,resprout and grow vigorously after
burns.Shallow-rooted shrubs such as cranberry are
destroyed in areas heavily burned to mineral soil;
however,burning to mineral soil is necessary for
establishment of willow seedlings (Densmore and
Zasada 1977,Densmore 1979).In the short term,
increased producti vity of browse pl ants such as
willow,aspen,and birch is likely as a result of
the release of soil nutrients (Figure E.3.117).
Many berry producing plants al so increase in den-
sity after fire (Friedman 1981).
E-3-238
-!
--
-'.
-
-I
-.
3 -BOTANICAL RESOURCES
The ecol og i cal effects of fi re on Al askan vegeta-
tion have-recei ved considerabl e attenti on duri ng
recent years,and the accumul ated knowl edge allows
a degree of prediction of the effects of a given
type of fire on a specifi carea •(This knowledge
plus increasingly effective fire control methods
have resulted in fire being used as a land manage-
ment tool to create desi red vegetation changes --
Section 3.4).
Wi 1dfi re is a common and natural phenomenon
throughout the needleleaf forests of interior
Alaska.Characteristics affected by fire in these
forests include:live biomass,dead and decaying
biomass,available nutrients,soil temperature and
soil moisture.Fire in black spruce forest greatly
reduces the overstory biomass,al though standing
dead snags may persist.Burning may partially or
completely oxidize organic constituents of the
forest floor,releasing large quantities of avail-
abl e nutrients such as phosphorus.Soil tempera-
tures become warmer throug h enhanced absorpt i on of
solar radiation.Permafrost,where present,
recedes because of severa.l factors incl uding
changes in al bedo and loss of vegetati ve insul a-
tion.Thus the active layer significantly
increases in depth (Viereck and Schandelmeier
1980)•
Fi re generally causes vegetati on to revert to an
earlier successional stage.The primary effect of
increased fire frequency in the coniferous commun-
ities of,the Susitna Basin will be to change the
veg.etation to earl ier herb or shrub seral stages,
si gnifi cantl y i ncreas ing avail able moose browse on
those areas (Figure E.3.117).
Coniferous forests usuall y revert to a herbaceous
or shrub stage (Foote 1979)characteri zed by rapid
nutrient turnover,high productivity,and rela-
tively high decomposition rates (Viereck and
Schandelmeier 1980).
Producti on of moose browse,especi all y willow,is
often very high during the shrub stage.Wolff and
Zasada (1979)found th.at3to 7 years after a fire
in bl ack spruce forest,the amount of wi 110w browse
available to moose increa"Sed680 percent from 6.5
to 44.1 kg/ha.The Bureau of Land Management
(unpublished data)reported a 1280 percenfincrea.-se
in wi 11 ow density from 1,800 to 23 ,000 stemslha in
7 years follow;ng a fire of moderate'intensity in
white spruce.
E-3-239
-~~~-~----
3 -BOTANICAL RESOURCES
In constrast to these potentially beneficial
effects of fi re on browse and berry production,
negati ve impacts may al so occur as a resul t of
vegetation removal and consequent soil insta-
bil ity.Fi res on steep slopes result in increased
runoff due to vegetation loss,and may cause mud or
landslides.In other areas thermokarst topography
and gullies may result from fires (Viereck and
Schandelmeier 1980).
3.3.2 -Devil Canyon Development
(a)Construction
(i)Vegetation Removal
Because of the narrow,steep configuration of Devil
Canyon,vegetation losses will be substantially less
than for the Watana Dam.Approximately 5700 acres
(2305 ha)of forest and 170 acres (70 ha)of shrub-
land will be inundated or cleared (Table E.3.84).An
additional 551 acres (223 ha)will be altered or lost
as a result of the camp,vill age,and borrow areas.
As discussed in the previous section,natural revege-
tation of some disturbed sites will probably occur.
Typical successional sequences reviewed in Section
3.3.1(b)(i)also apply to the Devil Canyon region.
(ii)Vegetation Loss by Erosion
The most likely source of vegetation loss by erosion
at the Devil Canyon site will be rock slides along
steep banks,especially on the south side of the
reservoi r.Al though most rockfall s wi 11 occur at
el evat ions of 900 to 1300 feet (274 to 396 m)and
thus will be below the eventual fill level,some
slides may also occur above this lone.Only sporadic
concentrations of permafrost have been found in Devil
Canyon.Resulting erosional problems and vegetation
loss through permafrost mel ti ng shoul d therefore be
minimal.Clearing may be a significant source of
erosion which may in turn result in further vegeta-
tion loss in adjacent unc1eared areas.
E-3-240
---------
3 -BOTANICAL RESOURCES
-
p-,
-.
(i i i )
(iv)
(v)
Vegetation Damage by Wind and Dust
Wind-related phenomena such as tree blowdown are less
1i kely at the Devil Canyon si te than at the Watana
site because the maximum fetch will be far less at
Devi 1 Canyon.Dust wi 11 be generated by cl eari ng of
the Dev il Canyon impoundment area,but because the
impoundment area is in a narrow valley that is more
protected from wind than the Watana impoundment area,
resulti ng impacts to vegetation are expected to be
relatively minor.
Effects of Altered Drainage
Excavation and construction activities w"ill impinge
on a number of small 1akes and ponds south of the
Devil Canyon site.A total of 32 acres (13 ha)are
covered by 1 akes withi n 10 mil es (16 km)of the
Susitna River at the Devil Canyon facility.Excava-
tion in these areas may result in the creation of new
aquatic or bog habitat with ensuing development of
bog vegetation (Neil and and Viereck 1977).The steep
configuration of the canyon will 1imit other changes
in drainage patterns or water table level s.Any
downslope cuts made.duri ng constructi on may,however,
promote active gully formation and associated vegeta-
tion loss.Proposed Borrow Area K (Figure E.3.37)
may affect an additional 99 acres (40 ha)of poten-
tial wetl ands.
Effects of Change in Albedo
Clearing of the Devil Canyon impoundment area will
result ina warming of underlyi ng soil s pri or to
filling.Since permafrost is not generally present,
impacts on adjacent vegetation will be minimal.
(vi)
(b)
Indirect Consequences of Vegetation Removal
Indirect effects of different clearing methodologies
were reviewed previously for the Watana site (Section
3.3.1{a)).These effects are also applicable to the
Devil Canyon area,although the steep configuration
of the canyon may make recontouri ng and topsoi 1 re-
placement efforts less effective.
Filling and Operation
The Devil Canyon impoundment will be filled in about two
months.No appreciable downstream effects on vegetation
should be evident during filling.Upstream from the dam,
E-3-241
.----'---
3 -BOTANICAL RESOURCES
filling will result in diminished dust in summer and perhaps
will slightly alter microclimate,especially on the windward
side of the reservoir (see Section 3.3.1(b)[iii]).
Because the drawdown zone for the Devil Canyon impoundment
will cover a range of 55 feet (17 m)during most of the year
as shown by the rule curve for Devil Canyon reservoir
(Exhibit B,Figure B.53),the rise and fall of the water
table will probably affect vegetation only in a narrow band
adj acent to the reservoi r.The consoli dated,rocky char-
acter of the substratum wi 11 inmost cases 1imit water
i ntrus i on and soi 1 waterl oggi ng,and few shifts toward wet
or bog vegetation are likely.
Relatively few additional impacts on vegetation are ex,pected
during operation of the Devil Canyon developm~nt.The old
large landslide at River Mile 175 (Figure E.3.3)could move
after filling,temporarily blocking river flow and flooding
upstream areas.This could cause a loss of mid-and late-
successional vegetation in areas such as the mouths an,d
floodplains of Fog and Tsusena Creeks.Howe.ver,the areal
extent of such impact cannot be reliably predicted.
Meso-and microcHmatic effects on vegetation will be very
small and probably well within the range of normal varia-
tion,due to the relatively small size of the reservoir.
(i)Vegetation Succession Following Clearing
The same general vegetational succession patterns
will occur on cleared,unsubmerged lands uf the Devil
Canyon area that were described for the Watana site
(see 3.3.1(b)[i]).However,due to the steep,rocky
character of Devil Canyon a much greater mosaic of
vegetation types may develop.On some slopes,loss
of soil may result in shifts to low-lying alpine
communiti es dominated bymountai n-avens,rather than
a gradual return to shrubland and forests.
(ii)Erosion and Deposition
Due to the geological character of the Devil Canyon
region,erosional/depositional changes affecting
vegetation will be minimal following filling of the
reservoir.
(i i i)Effects of Regul ated Flows
Downstream effects of the Devil Can;yon dam in the
re.ac hes downstream of Talkeetna,wtl:l .De similar to
those discussed in Section 3.3'.I(b)(iii).The
E-3-242
r---
,.,..
3 -BOTANICAL RESOURCES
factors controll ing vegetati on in the Devil Canyon-
Ta"lkeetna reach,however,wi 11 change as a result of
the lack of ice formation in this reach.With Watana
only,the rate of vegetative recession will be con-
trolled primarily by increased ice staging during
freezeup and secondarily by ice scouring at breakup.
The width of the unvegetated floodplain will increase
with a corresponding decrease in the si ze of
vegetated islands.Once Devil Canyon is operating,
ice scouring will be completely eliminated,and
vegetation w'ill be controlled by peak flows.Since
the peak flows wi 11 have a stage that is at 1east 5
feet below that when ice is present,many areas will
be available for primary succession after the con-
struction of the Devil Canyon dam.Succession will
follow the pattern shown in Figure E.3.78.
3.3.3 -Access
(a)Construction
Approximately 477 acres (193 hal of f1f'imarHY'shrub and
tundra vegetation will be cleared along a 44 mi (70 km)cor-
ridor for the Denal i Hi ghway-to-Watana access route (Tabl e
E.3.85).The vegetation adjacent to the access road will be
subject to indirect effects including dust deposition,
erosion,leaching of nutrients in recently drained regions,
and waterlogging in areas of blocked drainage.These
effects are all discussed in more detail in Section
3.3.1(a).
When the Devil Canyon dam is built,an additional road seg-
ment will connect the Devil Canyon and Watana sites along a
37 mi (59 km)corridor north of the Susitna River (Figure
37).Construction of this road w.i11 entail cl eari ng an
additional 468 acres (189 hal of roadway.A 12 mi (19 km)
railroad extension between Devil Canyon and Gold Creek will
be constructed on the south si de of the Sus itna Ri ver,
removing an additional 72 acres (29 hal of vegetation.
Spruce and mixed forest,tall and low shrub1and,and tundra
vegetation types will all be crossed by these corridors
(Table 85).
Many of the same impacts experienced in clearing the Watana
and Devil Canyon impoundments-(Sections 3.1.1(a),and
3.3.2(a))will occur during and followin9.access;.,re1ated
clearing.These include erosion,dust deposition~and
drainage changes.
E-3-243
3 -BOTANICAL RESOURCES
(b)Operation
Use of the access road s wi 11 resul tin conti nued dust-and
eros ion -re 1 ated effects on vegetat ion borderi ng the access
road.In addition,access roads will facil itate increased
human disturbances,including DRV use and a higher incidence
of fi re.These di sturbances and thei r impact on vegetation
are discussed in Section 3.3.1(b).
In contrast to the access roads,the proposed rai 1 connec-
tion from Devil Canyon to Gold Creek will minimize off-road
access and fire incidence.The rail connection will pri-
marily traverse spruce and mixed deciduous type forests.
3.3.4 -Transmission Corridors
(a)Construction
Transmission corridor comprise a total of 18,040 acres
(7300 hal and will consitute another source of vegetation
loss and/or disturbance (Tables E.3.79, E.3.80,and
E.3.86).The transmission lines from Healy to Fairbanks
cover a total of 7106 acres (2876 ha).Open bl ack spruce
(1270 acres,514 hal constitutes the main vegetation type in
the ri ght-of-way.The Wi 11 ow-to-Cook Inl et transmi ssi on
corridor (total cover 3209 acres,1299 hal will cross
primarily closed conifer-deciduous forest (568 acres,229
hal.The Willow-to-Healy transmission corridor (6184 acres,
2503 hal is composed primarily of upl and (2888 acres,1169
hal and lowland (1503 acres,608 hal spruce hardwood forest
types.Shrubland (457 acres,185 hal,tundra (390 acres,
158 ha),and forest (417 acres,117 hal are included in the
proposed ri ghts-of-way for the Watana-to-Gol d Creek trans-
mission corridors (total area 1541 acres,512 hal.
In all the above cases,the vegetation types affected repre-
sent small fractions (less than 4.2 percent)of the total
available vegetation types within the corridors.Of this
portion only a negligible fraction of the vegetation will be
totally el iminated by intermittent pl acement of control
stations,relay buildings,and towers.The remaining
vegetation will be_subject to selective clearing of trees
and tall shrubs There will be no clearing of low shrub or
tundra types.Thus 1ow-lyi ng vegetati on and small shrubs
will remain largely undisturbed.Such cleared areas have
the potential of increased browse production by willow and
birch shrubs following over-story removal.Transmission
corridor construction is described in Section 3.4.2(a).
E-3-244
3 -BOTANICAL RESOURCES
(b)Operation
""'"
....
......
After establishment of the transmission corridors,periodic
maintenance via selective clearing or trimming will be
required.Such manual clipping may stimulate leaf and twig
growth of willow and other browse species (Wolff 1978).On
the other hand,evergreen shrubs such as Labrador tea and
other woody shrubs are likely to show increased mortality if
damaged in the process of clearing (Chapin et ale 1975,
Chapin 1980,Chapin and Shaver 1981).But the potentially
most damag ing aspect of operati on may be increased ORV use
in the rights-of-way (see Section 3.3.1(b)(v).
3.3.5 -Impacts to Wetlands
(a)Construction
The direct removal of vegetation as a result of construction
and cl earing operati ons rel ati ve to the Watana and Devil
Canyon developments have been quantified in Sections
3.3.1(a)(i)and 3.3.2(a)(i).The primary vegetation types
to be removed by the impoundments,dam,and spillways of the
Watana development include stands of woodland and open black
and white spruce forest as well as some open mixed forest
types.Construction of the Devil Canyon facility will
result in the direct loss of forest and shrubland.As indi-
cated in Section 3.2.3 Wetlands,wetland classifications may
also be applied as a second level of classification to many
of the above vegetation types (Table E.3.81).Table E.3.82
i 11 ustrates the areal extent of different potential wetl and
vegetation types within the locations which will be affected
by the Watana and Devil Canyon developments.As indicated
previously (Secton 3.2.3),the estimates of total pal ustrine
wetland areas shown in the table are extremely liberal and
all values should be considered preliminary.
Far more potential wetland areas are included within the
Watana·development (30,705 acres,12,341 hal than occur
within the Devil Canyon project area (4214 acres,1706 hal
(Table E.3.82).The proportion of the area occupied by wet-
land types also differs within the two areas.Although
potential palustrine forested areas occupy the greatest
areal extent of wetl and types in the Watana faci 1 i ty (60
percent of total potential wetlands),this type occupies 48
percent of the potential wetl ands to be affected by the
Devil Canyon facility.Because of the configuration of
Devil Canyon,ri veri ne wetl and types occupy a greater pro-
portion of the potential wetlands of the Devil Canyon facil-
ity (47 percent)than of the Watana facility (18 percent).
E-3-245
3 -BOTANICAL RESOURCES
Within the Watana development area,about 11 percent of the
potential wetland areas occur within non-impoundment borrow
sites proposed for dam and ancillary facility construction,
whereas about 98 percent of potential wetlands within the
i mmedi ate vi ci nity of the Devi 1 Canyon development occur
within the dam,spillway,and impoundment areas.
Vegetation removal as a result of construction of access
corridors,Watana dam-to-intertie transmission corridors,
and the Healy-to-Fairbanks and Willow-to-Cook Inlet trans-
mission lines has been quantified in Tables E.3.85,E.3.80,
E.3.86,respectively.As indicated in Section 3.2.3,wet-
land classifications may also be applied as a second level
of classificaton to many of the vegetation types of Viereck
and Dyrness (1980).The reader is referred to the above
tables to review impacts to potential wetlands of the access
and transmission corridors,and to Table E.3.82 for a
general review.
3.3.6 -Prioritization of Impact Issues
In this section,impacts to vegetation are prioritized in order
from most important to least important.As discussed in Section
1.2,impacts are prioritized based on resource vulnerability,the
probabil ity of the impact occurring,and the duration of the
impact.Di rect losses of vegetation are judged most important
because of the certai nty and the permanance of the impact.The
importance of losses of particular vegetation communities is in
proportion to the total acreage lost and in indirect proportion
to the amounts of each type present regionally.
Pl ant community changes are judged to be 1ess important than
actual losses.These impacts are less predictable and of a
shorter duration than vegetation losses.
(a)Direct Loss of Vegetation
(i)Watana
Direct losses for the Watana project include 31,300
acres (12,667 ha)of vegetation for the dam,impound-
ment and spillway.An additional 4300 acres (1742
ha)have been designated for use as camp,village,
airstrip,and borrow areas.These potential losses
account for only 1 percent of all ,vegetation in the
middle Susitna basin,but 3.6 percent of the vegeta-
tion present in a 20 mile (32 km)wide area spanning
the Susitna Ri ver from the mouth of the Macl aren
River to Gold Creek.More importantly,substantial
losses of certain vegetation types will be sustained
E-3-246
3 -BOTANICAL RESOURCES
during construction of the Watana Dam.Losses of
forested areas may total 8.3 percent of the 20 mile
(16 km)wide area.Losses of open and closed birch
forest will be particularly large,greater than 20
percent for the 20 mil e (16 km)wi de area.The
losses of these forest types wi 11 mean substant i a 1
habitat losses for some wildlife,especially black
bear,moose,pine marten,beaver,raptors,small
mammals,and passerine birds.
I'"
-
(i i)
(ji i)
Devil Canyon
Direct losses for the Devil Canyon project will
i ncl ude 5871 acres (2376 ha)of forests,tundra and
shrubl and.Negl i gibl e amounts of tundra and shrub-
land (<.05 percent)will be lost,but 0.7 percent of
all forested lands in the middle basin (1.8 percent
of the 10 miles (16 km)area will be affected.
Because of the steepness of Devil Canyon,these
losses are relatively small compared to Watana and
comparatively less important for wildl ife.Again,
however,appreciable quantities of closed birch
forest (18.6 percent of the 10 mile,(16 km area)
will be eliminated.
Access Roads
The Watana access road wi 11 resul tin a loss of
approximately 568 acres (230 ha)of mixed tundra
vegetation types.Additional losses of about 494
acres (200 ha)for access roads and 78 ha (193 acres)
for rail will be utilized for access to the Devil
Canyon facility.These routes will span spruce
forests,tall and low shrubland and tundra vegetation
types.In relation to possible losses from other
aspects of the project,these direct losses are
small.
~,
(iv)Transmission C~rridors
Of the total 18,040 acres (7300 ha)of vegetation on
rights-of..;way for transmission lines,only a small
fraction need be subject to initial clearing since
t here wi 11 be no cl earing of low shrub or tundra
types.Access trails for transport of personnel and
materials,plus smaller areas for placement of con-
trol stations,relay buildings,and towers,will need
to be cleared;other portions of the transmission
corridors will only require selective clearing or
top-cutting of tall shrubs and trees.
E-3-247
3 -BOTANICAL RESOURCES
(b)Indirect Loss of Vegetation
Additional losses of vegetation may occur due to erosion,
permafrost mel ti ng and subsequent 1and sl i des and sl umpage,
ORV use,blowdown of trees and other causes (see Sect ion
3.3.1(a)).While some of these losses will be short-term
with typical vegetational succession ensuing,or with shifts
to new vegetation types for that area,long-term vegeta-
ti onal losses enduri ng for 30 to more than 100 years may
occur on sites of continual erosion,land slumpage,or ORV
use.The amounts that will be lost because of these factors
are small compared to amounts inundated by the reservoirs.
(i)Watana
Indirect losses of vegetation are projected to be
greatest at the Watana site,where large areas on the
south side of the impoundment are underlain by 200 to
300 feet (60 to 90 m)of permafrost at near melting
temperature.Al so,because of the expected 1arge
size of the reservoir,other erosional processes such
as wi nd erosi on,together with effects of dust,may
cause very 1oca 1i zed vegetat i on loss,espec i all yin
wind-exposed areas.
(ii)Devil Canyon
The smaller,steeper nature of Devil Canyon will
severely limit indirect losses of vegetation.Except
for the possibil ity of one massive flow near River
Mile 175,rock slides occurring above the impoundment
represent the greatest threats and these wi 11 resu1 t
in only small scale losses.
(iii)Access Roads
Some indirect loss of vegetation is expected due to
erosion caused by changes in drainage patterns and
dust deposition on the road edges. Increased uti1i-
zati on of ORVs along access roads and road mai nten-
ance may damage adjacent areas.
(iv)Transmission Corridors
Little indirect loss is likely as a result of direct
clearing or construction,but uncontrolled ORV access
could affect vegetation on and adjacent to corridors.
Forests,shrub1ands,tundra and wetlands are dis-
persed along this area.
E-3-248
-I
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3 -BOTANICAL RESOURCES
-
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(c)Alteration of Vegetation Types
Alteration of vegetation types will be caused by succession,
changes in drainage patterns,altered river flows,and fire.
In many instances,natural successi on of cl eared or di s-
turbed areas not subject to inundation wi 11 result in vege-
tati on type changes.For exampl e,primary herbaceous and
weedy vegetation and secondary shrub growth may follow
clearing of sites.There may be development of fast-growing
algal species and floating vegetation in shallow areas of
the impoundment(s).Successional trends following man-
caused fires are generally predictable.These impact issues
are discussed further in the mitigation section (Section
3.4)•
(i)Downstream Floodplain
The most important alteration to result from the
dames)will be downstream between Gold Creek and
Talkeetna,where annual spring and summer flooding
and scour by ice jams will be reduced.As a result,
some of the previously pul se-stabil ized communities
will mature.The willow and balsam poplar shrub will
change to mature balsam poplar and thence to spruce.
Within the license period,the development of vegeta-
tion on newly exposed banks and islands will proceed
only to the medium and tall shrub stages.
(i i)Watana
One area of potenti ally important impacts is tundra
vegetation surrounding the Watana Reservoir.Distur-
bance may cause warming of the soil,mel ting of the
permafrost,and deepeni ng of the acti ve 1ayer.In
well-drained areas,this may result in increased
growth and productivity by the existing plant com-
munity,but in waterlogged areas a shift to bog
vegetation is likely.If the organic layer is lost
during disturbance,long-term losses of vegetation
may result.
Most forest and shrub areas disturbed near the reser-
voir will recover naturally.The ensuing patterns of
vegetat i ona 1 success i on wi 11 be accelerated if the
organic layer is retained and if root suckers or
seeds of vegetation remain.
E-3-249
3 -BOTANICAL RESOURCES
(iii)Devil Canyon
Outside the actual impoundment and dam site,very few
alterations of vegetation types are anticipated at
Devi 1 Canyon.Forest types wi 11 be subject to mi nor
alterations,primarily near borrow sites G and K,and
near camp and village sites.Likewise,changes in
drainage,waterlogging of soil or permafrost melting
will be highly localized because the soil is gener-
ally very rocky and well drained,with only sporadic
occurrences of permafrost.The small er,steeper
character of Dev"il Canyon will al so act to 1 imit
micro-climatic and mesoclimatic alterations.
(iv)Access Roads and Railroads
The access roads between the Devil Canyon and Watana
sites and between Watana and the Denali Highway,as
well as rail construction between Devil Canyon and
Gold Creek,will alter surface drainage patterns and
may induce dust-related alterations in vegetation at
roadsides.The effects of altered drainages have
been summarized above.
(v)Transmission Corridors
Selective clearing or top-cutting of tall vegetation
will result in local shifts in plant types from trees
to shrubs.Wet and moi st tundra areas and thei r
peri pheri es wi 11 be more suscepti b1e to water log-
ging by vehicular traffic with subsequent development
of bog species and/or black spruce in place of
cottongrass and shrub species.
3.4 -Mitigation Plan
3.4.1 -Introduction
This mitigation plan addresses the impacts to botanical resources
described in Section 3.3.Mitigation measures for each impact
issue have been developed according to the approach discussed in
Sections 1.2 and 1.3,and are prioritized as follows:avoidance,
minimization,rectification,reduction,and compensation.Miti-
gation measures are described with respect to locations,proce-
dures,and costs.Recommendations by state of Al aska and federa 1
agencies are reviewed,and their relationship to the mitigation
plan explained.
E-3-250
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3.4 -Mitigation Plan
The mitigation plan is organized as follows:
(a)Section 3.4.2,Option Analysis:
-The range of available mitigation options is explained for
each of the impact issues prioritized in Section 3.3.6.
-Selected mitigation measures or facilities are described
along with the reasons supporting each selection.
-The extent to which mitigation will be achieved by area
and over time is indicated where available information
allows.
-Residual impact estimates are provided.
-Impl ementat i on s~hedul es are presented commensurate with
the level of detail provided by Exhibit C,Construction
Schedule.
-Implementation costs are provided for measures or facili-
ties which are not included as project capital costs
(Section 4.4.3).Project capital costs are described in
Exhibit D.
-Mitigation measures or facilities recommended through
agency consultation are documented.Where such recommen-
dations have been incorporated in the mitigation plan,ex-
planation is provided.Cases where alternative measures
have been adopted are also explained.
-Illustrations of mitigative project design features are
presented.
(b)Section 3.4.3,Mitigation Summary:
-Mitigation measures for botanical resources are summarized
including schedules and cost estimates for future studies
(Table E.3.177).
(c)Section 4.4.4,Agency Consultation (including wildlife):
-Mitigation recommendations provided through agency consul-
tation are summarized,along with reasons for incorpora-
tion of alternative measures where appropriate.
E-3-251
3.4 -Mitigation Plan
Environmental protection guidelines provided to project engineers
are shown in Appendix 3.B.A majority of these recommendations
have been incorporated into engineering design and construction
planning,resulting in modifications to avoid or minimize adverse
impacts to botanical resources during project construction and
operation.These measures include changes in facility siting and
layout,realignment of access roads and transmission corridors,
alterations in road design and construction,and constraints on
gravel extraction locations and procedures.Because removal of
vegetation will produce the greatest direct impact to botanical
resources of the project area,measures to minimize the areal
extent of vegetation removal are treated in greatest detail in
the following discussions.
Rectification of adverse impacts to wetlands has also received
particular attention,especially with regard to correcting block-
age of sheet flow and siltation conditions caused by construction
of access and service roads.Rehabilitation measures to rectify
vegetation and soil loss at temporary construction sites and bor-
row areas have also been incorporated,including procedures to
conserve and replace soils and to revegetate disturbed areas.
Project planning has emphasized the reduction of adverse impacts
to wetlands and downstream riparian vegetation during construc-
tion and operation through monitoring and corrective measures to
be implemented during the license period.Measures to compensate
for impacts to vegetation refl ect the importance of botanical
resources as components of wildlife habitat,and have been
designed primarily to mitigate impacts t~wildlife through habi-
tat enhancement and replacement.Thus,the mitigation plans for
botani ca 1 resou rces and wil dl ife compl ement each other,and mea-
sures designed largely to reduce or compensate for loss of wild-
life habitat are discussed more fully in Section 4.4.
As the Power Authority continues to sponsor field studies to re-
fine and further quantify information obtained during the past
three years of baseline and impact research,and as engineering
design and construction planning proceed,features of this miti-
gation plan will be correspondingly refined with respect to spe-
cific locations,procedures,and costs.
3.4.2 -Option Analysis
(a)Direct Loss of Vegetation
Without mitigation,construction of all project facilities
would remove vegetation from a total of about 68,537 acres
(27,744 ha),apportioned as follows:
E-3-252
3.4 -Mitigation Plan
acres hectares
-.
-Dams and spillways
-Impoundments
-Camps
-Vi 11 ages
-Ai rstri p
-Damsite borrow areas
-Access borrow areas
-Access routes
-Transmission corridors*
274
44,292
245
269
42
4,325
35
1,015
18,040
111
17,932
99.
109
17
1,751
14
411
7,300
-
*Ground layer and soil not removed.
Of thiscumu1att~e impact,vegetation removal resulting from
dams and spillways,impoundments,access routes,and the
Watana operational village will be permanent,accounting for
about 70 percent (45,581 acres,18,454 ha).The remaining
30 percent (19,236 acres,7788 ha)will allow application of
the following range of mitigation options:
-Avoidance:Vegetation"removal cannot be entirely avoided.
-Minimization:This measure is feasible by reducing clear-
ing requirements.Options include:
Minimizing facility dimensions;
•Consolidating structures;
•Siting facilities in areas of low biomass;
Siting facilities to minimize clearing of less
abundant vegetation types;
•Siting facilities to minimize clearing of vegetation
types productive as wildlife habitat components;
•Minimizing volume requirements for borrow extraction;
•Disposal of spoil within the impoundments or previously
excavated areas;and
•Designing transmission corridors to allow selective
cutting of trees and to accommodate uncleared low shrub
and tundra vegetation types within the rights-of-way.
E-3-253
3.4 -Mitigation Plan
-Rectifi cati on:Site rehabil itati on measures can rectify
impacts of vegetation removal.Options include:
•Dismantling nonessential structures as soon as they are
vacated;
Storing removed organic layer and mineral soil for sub-
sequent replacement;
•Scarification and fertilization;and
•Artificial seeding.
-Reduction:Impacts of construction-related vegetation re-
moval can be reduced over time by:
•Monitoring progress of site rehabilitation to identify
locations requiring repeated application of fertilizer
and/or seed;
•Systematically identifying and rehabil itating areas
where construction activities have ceased and are no
longer required.
Coordinating rehabilitation efforts with closure or re-
moval of service roads no longer required.
-Compensation:This approach is feasible through the ac-
quisition and management of replacement lands.Options
i ncl ude:
•Acquiring lands with areal coverages of vegetation types
equivalent to those lost,and protecting these lands
from future development.
•Prioritizing lost vegetation types relative to value as
wildlife habitat,and selectively changing vegetation on
acquired lands to replace or exceed lost areal coverages
of the high-priority vegetation types.
(i)Minimization
All of the minimization options summarized above will
be applied to reduce clearing requirements to the least
necessary for proj ect constructi on.Dimensions of the
construction camps and villages have been kept small by
designing compact arrays of uniformly-sized,contiguous
residential modules,as shown in Exhibit F,Plates F36,
E-3-254
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3.4 -Mitigation Plan
F37,F71,and F72.This approach has afforded signifi-
cant structural consolidation,enhanced by combining
the permanent vi 11 age or townsite with the temporary
construction village at Watana (Exhibit F,Plate F36).
Structural consol idation has been achieved further by
confining the entire infrastructure of camps,villages,
temporary roads,fuel and equipment storage areas,and
other construction support facil ities to the vicinity
of the damsite.At Watana,the construction camp is
sited about 2.5 miles (4 km)and the village about 1
mile (1.6 km)northeast from the emergency spillway
(Exhibit F,Plate F3).At Devil Canyon,the construc-
tion village is about 2.7 miles (4.3 km)and the con-
struction camp about 1.5 miles (2.4 km)west from the
emergency spillway,and the railhead pad (approximately
2500 by 800 feet)is about 1.5 mil es (2.4 km)to the
southwest (Exhibit F,Plate F70).These siting
arrangements have been determined primarily by the
nearest available flat terrain to the damsites.
A major consolidation feature incorporated into project
desi gn is the common corri dor of the Watana-to-Go 1d
Creek access and transmission routes (Figures E.3.37,
E.3.39,and E.3.40).Vegetation removal required for
both facilities will affect approximately similar plant
communities in approximately the same locations (com-
pare Tables E.3.80 and E.3.85,and see Figures E.3.39
and E.3.40).Consolidation of the two routes will min-
imize traffic-related vegetation removal by reducing
distances requi red for transport of equi pment from the
nearest road to the transmission corridor.In the
stretch between Watana and Devil Canyon,the adjacent
access road will allow direct overland entry of equip-
ment across a di stance rangi ng from about 0.1 to 0.75
miles (up to 1.2 km).Equipment will be mounted on
flat-tread,balloon-tire vehicles to minimize soil or
ground-cover disturbance.
Further consolidation has been achieved by siting bor-
row areas whi ch may be requi red for access road con-
struction immediately adjacent to the route.As shown
in Figure E.3.37,14 borrow areas have been identified
along the access'route from the Denali Highway to Devil
Canyon.Access routing has been refined to emphasize
well-drained soils which will allow maximum use of
side-borrow techniques in level terrain and balanced
E-3-255
3.4 -Mitigation Plan
cut-and-fill in sidehill cut areas (Figure E.3.83).
Therefore,the borrow areas shown in Figure E.3.37 are
not expected to be fully excavated,as they wi 11 be
used only to augment material requi rements where side-
borrow or bal anced cut-and-fi 11 techni ques cannot be
fully utilized.In general,it is expected that each
site wi 11 be excavated at most to a depth of 8 feet
(2.5 m)and will range in area from less than 10 to no
more than 20 acres (4 to 8 ha).
By minimizing gravel extraction requirements and util-
izing borrow areas which,if necessary,will be sited
immediately adjacent to the access road,the need for:'
individual access roads to borrow areas has been elim-
inated,further reducing requirements for vegetation
removal.
Facility siting has emphasized areas of low biomass.
The Watana construction camp and village have been
sited in low shrub types (birch and mixed;see Table
E.3.83);these have relatively low clearing require-
ments in comparison to the open mixed forest and tall
shrub stands also in the vicinity,which have been
avoided (Figure E.3.40).At Devil Canyon,the camp and
village have been sited in comparatively well-drained,
closed,conifer-deciduous forest (Table E.3.84)to
avoid nearby low,wet areas of black spruce and wet
sedge-grass (Figure E.3.39).Hence,the Devil Canyon
ancillary facilities will remove more biomass than
facilities of equivalent area at Watana.
Minimizing clearing requirements has been a major con-
sideration in the siting of access roads,particularly
the Denali Highway-to-Watana section where completion
within the first year of construction,1985,is re-
quired (Exhibit C,Figure C.1;Exhibit E,Chapter 10,
Section 2.3.7[b]).The Denali Highway-to-Watana route
will remove about 343 acres (139 ha)of shrubl and and
about 132 acres (53 ha)of tundra types,accounting for
about 0.1 percent of total shrubland in the Watana and
Gold Creek watersheds and a lower percentage of total
tundra cover (Table E.3.85).Only 0.9 acres (0.3 ha)
of open white spruce forest will be affected,and the
number of individual trees actually cut in this low-
density vegetation type will be statistically insignif-
icant on a local or regional basis.
Opposit i on to the Denal i Hi ghway-to-Watana route has
been stated in letters from the ADF&G (1980,1982),the
E-3-256
....,
I
3.4 -Mitigation Plan
the Susitna Hydroelectric Steering Committee (1981),
and the USFWS (1982,1983).The major wildlife concern
expressed is that habitat for cari bou,moose,brown
bear,and black bear will be crossed by this access
alternative.The route has been selected because of
the scheduling requirement cited above for completion
of access to Watana during the first year of construc-
tion.This route is discussed further below and in
Section 3.4.2(b),and in the fish and wildlife impact
and mitigation discussions,Sections 2.3,2.4,4.3,and
4.4,respectively.
The Watana-to-Devil Canyon route also is characterized
by vegetat i on types of predomi nant 1y low bi omass,a 1-
though it crosses a greater variety of pl ant communi-
ties.Abou~48 percent of the route is shrubland (224
acres,91 ha),32 percent is tundra (151 acres,61 ha),
and 20 percent is forest (92 acres,37 ha)(Table
E.3.85).This routing has been recommended by the
ADF&G (1980),the Susitna Hydroelectric Steering
Committee (1981),and the USFWS (1982).The route has
been incorporated as recommended,and is discussed
further below and in Sections 3.4.2(b),4.3,and 4.4.
The Devil Canyon-to-Gold Creek railroad route will
traverse almost entirely closed mixed forest (about 50
acres,20 ha)and open mixed forest (about 14 acres,6
ha)(Table E.3.85).In thi s case,constrai nts imposed
by criteri a for maximum 2.5 percent grades and
10-degree hori zontal curves have necessitated routing
through a heavi er-bi omass vegetation type.However,
the rail mode is itself a mitigation measure in this
respect,because clearing width (50 feet,15 m)is less
than half that required for road construction (120
feet,37 m).
Rail access to at least Devil Canyon,and preferably
excluding a road system connecting with Alaska high-
ways,has been recommended by the Susitna Hydroelectric
Steering Commmittee (1981)and the U.S.Fish and Wild-
life Service (1982).The rail mode has been incorpor-
ated as recommended.However,a connecting road system
has also been incorporated,although through Watana and
the Denali Highway and not directly west to the Parks
Highway.This issue is discussed further in Section
3.4.2(b)•
E-3-257
3.4 -Mitigation Plan
Transmission corridors traverse a variety of vegetation
types with different biomass characteristics (Tables
E.3.77-79 and E.3.86,Figures E.3.39-40 and E.3.49-52).
Their routing has been determined largely by access and
1 and ownership considerations.Because it shares a
common corridor,the Watana-to-Devil Canyon transmis-
sion route traverses low-biomass vegetation types simi-
lar to those crossed by the adjoining access road.
Clearing of vegetation of any type will be minimal
during transmission corridor construction.Mitigative
clearing techniques specifically designed to minimize-
vegetation removal by transmission corridors are
discussed below.
Impacts of vegetation removal are relatively greater if
the vegetation types removed are 1ess abundant (have
lower total areal coverage)than other plant communi-
ties in the project area.Vegetation types with low
areal coverage within the Watana and Gold Creek water-
sheds are closed spruce forest,open and closed birch
forest,herbaceous al pi ne tundra,and wet sedge-grass
tundra (Table E.3.51).Within the 20-mile-wide (32 km)
area surveyed in greater detail along the Susitna River
from the Maclaren River (RM 260)to Gold Creek (RM
136.8),less abundant vegetation types are herbaceous,
closed balsam poplar forest,grassland,open and closed
birch forest,and wet sedge-grass tundra (Table
E.3.52).Herbaceous alpine tundra will not be affected
by the project (McKendrick et ale 1982).The herbac-
eous,balsam poplar,and grassland types occur primar-
ily along the downstream floodplain and tributaries of
the Susitna River (McKendrick et al.1982)and wi 11
not require direct vegetation removal for facility con-
struction with the exception of 111 acres (45 ha)of
herbaceous floodplain pioneer vegetation to be inun-
dated by the Watana impoundment and 0.7 acres (0.3 ha)
of closed bal sam popl ar to be cl eared for rai 1 road
construction (Tables E.3.83 and E.3.85).However.
these vegetation types will potentially be affected by
regulated flows,as discussed in Section 3.3.1(c).A
balsam poplar stand near Deadman Creek at access mile-
post 37.5 has been avoided by a one-half-mile route
realignment to protect a bald eagle nest in the stand
(Section 4.4,Figure E.3.81).
Low abundance vegetation types whi ch will recei ve the
greatest cumulative impact from construction of the im-
poundments and dams,access and transmission corridors,
and all ancillary facilities will be closed spruce for-
est,open and closed birch forest,and wet sedge-grass
E-3-258
-!
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3.4 -Mitigation Plan
tundra (Tables £..3.80 a.nd E.3.83-86).A total of 252
acres (102 hal of closed spruce forest will be tra-
versed by the transmi ss ion corri dors.Based on
1:250,000-scale mapping of the project area (Table
E.3.51),as much as 32 percent of the total coverage of
closed spruce forest in the Watana and Gold Creek
watersheds (i.e.,798 acres or 323 ha)could potential-
ly be cleared during the winter of 1989-1990.However,
the application of selective clearing and other mitiga-
tive techniques involving transmission corridor con-
struction will reduce the actual number of individual
trees removed,as discussed below.
A cumulative total of 3428 acres (1388 ha)of open and
closed birch forest could be affected by construction-
rel ated cl eari ng between 1985 and 2002.Based on the
1:63,360-scale mapping of the 20-mile (32-km)strip
along the Susitna River for which the greatest deta.il
is available (Table E.3.52),36 percent of the total
9440 acre's (3822 ha)of this vegetation type could be
removed by construction.About 2250 acres (911 ha)or
24 percent of the total coverage wi 11 be ent ire1y re-
moved by clearing of the impoundments (Tables
E.3.83-84).The remaining 1178 acres (477 ha)will be
selectively cleared as discussed further below.
The third low-abundance vegetation type to be affected
by constructi on,wet sedge-grass tundra,wi 11 be
crossed by access and transmission corridors (481
acres,195 ha)(Tables E.3.80 and E.3.85-86)and inun-
dated withi n the impoundment areas (235 acres,95 ha)
(Tables E.3.83-84).Borrow Area 0 (Figure E.3.37)will
potentially remove an additional 20 acres (8 ha)(Table
E.3.83).The siting of all pads,buildings,and other
structural facilities has entirely avoided this vegeta-
tion type.Therefore,a total of 736 acres (298 ha)of
wet sedge-grass tundra will be potentially affected by
construct i on between 1985 and 2002.Thi s cumul at i ve
impact represents about 9 percent of the total 8687
acres (3517 ha)present within the 20-mile (32-km)
strip mapped at 1:63,360 (Table E.3.52).Mitigative
measures which will minimize drainage alterations in
this wet vegetation type are discussed in Section
3.4.2(c).
In summary,siting of pads,buildings,the Watana air-
strip,and other ancillary facilities has minimized
clearing requirements Tor low-abundance vegetatlon
types.As residual impact,the impoundments and access
and transmission corridors will remove about 32 percent
E-3-259
3.4 -Mitigation Plan
of closed spruce forest in the Watana and Gal d Creek
watersheds,as well as 36 percent and 9 percent of
bi rch forest and wet sedge-grass tundra,respecti vely,
within the 20-mile (32-km)strip mapped at 1:63,360.
Construction-related impacts of vegetation removal can
be minimized further by siting facilities to avoid pro-
ductive wildlife habitat.In this sense,the affected
vegetation has less value,and thus its removal
contributes less to cumulative impact.However,this
option applies only to facilities with flexible siting
requi rements.Because the dam and impoundment sites
are fi xed,loss of vegetat i on as a resul t of thei r
construction cannot be minimized,rectified,or reduced
over time,but can be offset only through compensation,
as explained later in this section.
Without mitigation,the clearing of vegetation for per-
manent facilities will reduce carrying capacity for
wildlife,as discussed in Sections 4.3 and 4.4.1;miti-
gation plans to offset this loss are presented in Sec-
tion 4.4.2.These plans include the selective siting
of access roads,transmission corridors,borrow areas,
and the Devil Canyon railhead facility to minimize re-
moval or disturbance of wildl ife habitat.Siting and
route alterations for this purpose have been made
through the interaction of environmental specialists
with project engineers and are summarized in Figures
E.3.79-82.
Vegetation removal resulting from access road construc-
tion would be minimized most completely by selection of
the shortest alternative route (Access Plan 13--see
Chapter 10,Section 2.3).However,as stated above,
schedule constraints have necessitated selection of the
93-mile (149-km)Plan 18 route,which provides road
access from the Denal i Hi ghway and rai 1 access from
Gold Creek.This route incorporates siting and design
features which will minimize removal of wildlife
habitat.A major advantage is that moose and brown
bear habitat south of the Susitna River,particularly
near Prairie Creek,Stephan Lake,and the Fog Lakes,
will not be directly affected by vegetation removal and
other construction-related impacts.This avoidance of
productive habitat south of the Susitna River agrees
with and implements recommendations of the ADF&G
(1980,1982),the Susitna Hydroelectric Steering
Committee (1981),and the USFWS (1982).
E-3-260
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3.4 -Mitigation Plan
As shown in Figure E.3.79,two major realignments have
been made to the 42-mi 1e (67-km)Denal i Hi ghway-to-
Watana segment,progressively moving the route westward
from relatively flat,low terrain (2000-3500-foot
(600-1050 m)elevation)to the lower slopes of
mountainous terrain in the northern portion of the
project area (3500-4000-foot (1050-1200 m)elevation).
These real i gnments have provi ded several advantages.
First,potential drainage and siltation impacts
associated with construction in the low,wet terrain to
the east have been avoided.Second,the two earl ier
route alternatives joining the Denali Highway near
Snodgrass and Butte Lakes were longer and woul d have
crossed more streams and wet areas.For example,the
Butte Lake alternative passes within 100 yards (91 m)
of Deadman LaRe for a continuous distance of 2 mil es
(3.2 km)and closely transits Deadman Creek along a
5-mile (8-km)stretch.In addition,the earlier
alternatives crossed flat terrain historically within
the range of the Nelchina caribou herd (Section 4.2).
The adjusted route follows the transition zone between
level range and mountainous terrain,leaving the
lowland area uncrossed by any potentially disturbing
structure.Third,the adjusted route now follows
relatively well-drained terrain and soil types which,
for the most part,allow construction using side-borrow
or bal anced cut-and-fill techni ques,rather than the
bermed construction mode required for roadbeds crossing
wet,poorly drained areas.
As discussed in greater deta"il below,side-borrow and
balanced cut-and-fill techniques provide road sections
which present less of a physical and visual barrier to
passing wildl He such as caribou and moose.Thus,
where vegetation is replaced by a physical structure,
the potential for that structure to block free passage
of big game has been reduced by selective siting which
allows preferred construction modes.
Us i ng side-borrow and balanced cut-and-fi 11 techn i ques
also reduces gravel requirements,thereby minimizing
the areal extent of vegetation removal,and confines
gravel extraction to the access corridor itself,thus
consolidating the impact.Similar terrain and soil
considerations have governed routing of the 37-mile
(59-km)Watana-to-Devil Canyon road and the 12-mile
(19-km)railroad extension,which will also rely on
balanced cut-and-fill construction to minimize removal
of wildlife and habitat.
E-3-261
3.4 -Mitigation Plan
In addition to the major realignments described above,
options for small er route adjustments have been fully
exercised to avoid site-specific habitat loss or direct
disturbance of wildlife.These local modifications and
the features avoi ded are documented in Fi gures
E.3.80-82.Red fox den complexes and surrounding habi-
tat (characteristic of well-drained,sloping terrain)
have been avoi ded by careful ori gi nal rout i ng or
changes ina 1i gnment at MP 28,32, 34,and 36.At MP
38,the original alignment passed through a balsam
poplar stand containing a bald eagle nest.In
compliance with provisions of the Bald Eagle Protection
Act (16 USC 668-668c),the route has been realigned to
pass 0.5 mile (0.8 km)west of the nest location.As
shown in Figures E.3.80 and E.3.81,additional route
changes have been made to avoid impacts to surrounding
palustrine vegetation,water quality,and resident fish
of Deadman and Tsusena Creeks.These real ignments are
discussed from a fisheries standpoint in Section 2.4.
West of the Watana damsite,access routing has been ad-
justed to avoid potential disturbance to the fox den
complex (not shown)at Swimming Bear Lake (MP 18 of the
Watana-to-Devil Canyon route).Beaver concentrations
at MP 34 and 36 in the vicinity of the Devil Canyon
damsite have also been avoided by road realignments,as
shown in Figure E.3.82.Particular attention has been
given to the golden eagle nest on the cliff along the
north side of Devil Canyon at MP 34.5.The access
route in this vicinity was realigned to avoid the nest
site by 0.5 mile (0.8 km)to the north (Figure
E.3.82).
Jack Long Creek,a productive beaver stream,occupies a
swale approximately 1700 feet (515 111)south of the
Devil Canyon construction village and campsite (Figure
E.3.82).This stream and the surrounding wet area are
vulnerable to impacts of vegetation removal associated
with construction of the camp and village,transmission
corridor,and access route.Options to minimize dis-
turbance to Jack Long Creek and resident beaver include
resiting the camp and village,selecting road instead
of rail access from Gold Creek to provide greater flex-
ibility in access routing,realigning the rail route to
the extent feasible,and aligning the transmission
corridor away from the creek.
As explained earlier in this section and shown in Fig-
ure E.3.39,the camp and village are subject to siting
E-3-262
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3.4 -Mitigation Plan
constraints imposed by the occurrence of wet sedge-
grass vegetation type in the area,and have been sited
on locally higher,drier terrain supporting closed
mixed forest.Their locations are considered to be
sufficiently flat and distant from Jack Long Creek to
prevent erosion runoff into the drainage following
vegetation removal.
Selection criteria and rationale for rail access from
Gold Creek are explained in Exhibit E,Chapter 10,Sec-
tion 2.3,and are considered sufficiently favorable to
prevent changing access from Gold Creek to road instead
of rail.Agency recommendations have consistently sup-
ported this position (SHSC 1981,USFWS 1982).There-
fore,the rail alignment has been modified to follow
the hillside south of Jack Long Creek at approximately
the 1600 to 1800 feet (500 to 550 m)contour level,
instead of the original alignment on lower ground along
the north side of the creek (Figure £.3.82).The
mod ifi ed ali gnment will keep the railroad extens ion
away from the active drainage area of Jack Long Creek.
The railhead facility at Devil Canyon will consist of a
poured concrete pad approximately 2500 feet (758 m)
long and 800 feet (242 m)wide,accommodating the main
track,two sidings,and areas for equipment,
offloading,and storage.The Jack Long Creek drainage
and a beaver pond near the head of the drainage system
impose diffi cul t constrai nts on the siting of thi s
facility.The pad was originally sited on the north
side of the creek between the streambed and the Devil
Canyon campsite.With real ignment of the rail
extension to avoid impacts to the drainage,the
railhead facility has also been relocated south of the
creek on relatively flat ground at an elevation of
about 1500 feet (454 m).This siting avoids both Jack
Long Creek and the beaver pond,and removes any
necessity for the,rail extension to cross the drainage
at this point (Figure E.3.82).Crossing of the
drainage to allow access to the camp and construction
areas will be accomplished by construction of a bridge
with minimal vegetation removal.This issue is
discussed further in Section 3.4.2(c)with respect to
potential drainage alteration.
The transmission corridor has been aligned to avoid
Jack Long Creek and is not expected to produce
constructi on-rel ated impacts on beaver habitat.
Access to the corridor for constructi on wi 11 be by
temporary bridge across Jack Long Creek from the rai 1
corridor.
E-3-263
3.4 -Mitigation Plan
In summary,potenti al effects of constructi on-rel ated
vegetation removal on wildlife habitat have been min-
imized by routing access and transmission corridors as
much as possible away from areas where these structures
would disturb big game and fishery resources.In all
cases,specific locations of nests,dens,and beaver
activity have been entirely avoided by facility siting.
Impacts of vegetation removal during construction have
also been minimized by reducing volume requirements for
borrow extract ion.The opt ions chosen to accompli sh
this are use of side-borrow and balanced cut-and-fill
techniques in access road design,and incorporation of
a flexible design speed.As explained above,applica-
t i on of construction procedures depends on types of
terra in and soil traversed.Siting of access routes
has therefore avoi ded low,wet areas and made max imum
use of well-drained,higher terrain where gravelly
soils are available as construction material.This ap-
proach has the additional advantage of avoiding po-
tential wetlands and waterbodies,thus minimizing
drainage-and siltation-related impacts to aquatic re-
sources.
The section of road from the Denali Highway to the
Watana camp (41.6 miles,66.6 km)follows terrain and
soil types which wi 11 allow constructi on usi ng
primarily side-borrow techni ques.Thi s approach
minimizes vegetation removal away from the alignment by
confining road construction activities to an
approximately 20-feet (6-m)strip along each side of
the roadbed.A typical cross-section of a road
constructed by side-borrow is shown in Figure E.3.83.
The finished road section using side-borrow
construction is such that the crown of the road is only
2 to 3 feet (less than 1 m)above original ground level
compared with 5 to 6 feet (up to 2 m)for a
conventional berm-type,end-dumped section.Thus the
side-borrow approach not only minimizes vegetation
removal and consolidates disturbance,but also produces
less of a visual and physical barrier to passing
wildlife.
In side-borrow construction,the road is developed in
800 to 1000 feet (240 to 300 m)segments.Overburden
is removed,hauled to the previously constructed
segment,and deposited in the previously excavated
borrow trenches.Only at the start of construction is
overburden deposited on undisturbed vegetation,and
then only within the corridor which will be developed
subsequently.As the borrow trenches alongside the
roadbed are excavated,the borrow is used to build the
E-3-264
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3.4 -Mitigation Plan
road.Upon completion,the removed overburden is
hauled back from its temporary storage location in
borrow trenches of the previously constructed road
segment and used to backfill the newly excavated side
trenches to provide a 4:1 to 6:1 slope which helps to
stabilize and insulate the shoulder (Figure E.3.83).
The overburden is then fertilized and seeded.
In contrast to end-dumping,side-borrow does not re-
qui re the excavation of materi al sites away from the
alignment.As shown in Figure E.3.37,nine borrow
areas have been identified along the Denali Highway-to-
Watana segment as far as MP 32.These wi 11 be exca-
vated only on a contingency basis to support road con-
struction in cases where side-borrow material is not
available in sufficient quantities.In this event,ex-
cavati on requi red for maximum materi a 1 extracti on to
develop a given segment of road will average about
8 feet (2.5 m)in depth and remove vegetation over an
area of from 10 to no more than 20 acres (up to 8 ha).
Removed overburden will be stockpil ed temporaril yin
nearby locations selected and prepared on a site-
specific basis to minimize runoff potential (i.e.,
flat,well-drained upland locations not above streams
and with no acti ve or intermittent drai nage nearby,
with appropriate berms and/or trenches),then deposited
back in the borrow area and immediately fertilized,
scarified and seeded.Materi al requi red to support
constructi on of the Denali Hi ghway-to-Watana segment
south of MP 32 wi 11 be obtai ned from damsite borrow
areas D or E (Figures E.3.37 and E.3.40).
The connecting road between Watana and Devi 1 Canyon
crosses primarily low shrub and tundra vegetation types
(Table E.3.85,Figures E.3.39-40 and E.3.43-44)under-
lain by usable soils with bedrock at or near the
surface.Thi s road segment will be constructed by
sidehill cutting emphasizing balanced cut-and-fill to
mi nimi ze ancill ary materi al extraction.As shown in
Figure E.3.37,five potential borrow areas have been
identified along the route on a contingency basis in
the event that additional fill is needed to augment
materi a 1 obtai ned from s idehill cuts.These borrow
areas,if used,will have excavated dimensions not
exceeding those described above for the Denali Highway-
to-Watana segment.
Balanced cut-and-fill construction generally is fea-
sible only where excessively deep cuts are not required
E-3-265
3.4 -Mitigation Plan
to minimize grades.Routing of the Watana-to-Devil
Canyon road has followed gentle-to-moderate slopes
where deep cutting will not be required.However,in
steeper terrain such as approaches to stream crossings
and the high-level Susitna River bridge,requirements
for deep cutting have been greatly reduced by incorpor-
ating a flexible design speed which will allow steeper
grades and shorter-radius horizontal curves than a uni-
form 55 mph design speed would accommodate.In these
cases,design speed will be reduced to no less than 40
mph,minimizing the need for fill material from extran-
eous materi a 1 sites.Incorporat i on of desi gn speed
flexibility has also allowed the alterations in align-
ment to avoid biologically sensitive features described
above,as shorter-radius curves were required in some
cases.
In summary,impacts of construction-related vegetation
removal have been mi nimi zed by reduci ng vol ume
requirements for borrow extraction.This has been
accomplished by:
•Access alignments which follow well-drained upland
terrain with soil s suitable for use as construction
material;
Use of side-borrow and balanced cut-and-fill road and
railroad construction techniques;and
•Incorporation of a flexible road design speed to
avoid the necessity for deep sidehill cuts with ex-
cess i ve fill requ i rements.
The di sposa 1 of spoil from const ruct i on and borrow ex-
cavations will create a potential for vegetation re-
moval either through direct burial or through clearing
for spoil disposal sites.Spoil will be produced
primarily from the processing of excavated rock and
gravel required for dam construction,concrete
aggregate,and support pads for buildings and temporary
service roads.The locations of proposed excavation
areas are shown in Exhibit E,Chapter 2,Figures
E.2.132-135 and E.2.187-189,and in Figures E.3.37 and
E.3.39-40;borrow areas are described ;n Chapter 10,
Sections 2.5.1 (Watana)and 2.5.2 (Dev;l Canyon).
Large vol urnes of spoil will be produced between 1986
and 1991.For example,about 60 mcy of material will
be requi red from borrow areas E and I for the outer
shell of the Watana dam.About 32 percent by volume of
pit-run·materia]from these sites is estimated to be
E-3-266
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3.4 -Mitigation Plan
silt and sand which will be removed by washing and
screening (wet processing).Therefore a total of about
88 mcy will be excavated,producing about 28 mcy of
spoil requiring disposal.
The on ly cost-effect i ve way to avoi d removi ng vegeta-
tion for disposal of the large volumes of spoil pro-
duced by dam construction will be to deposit the spoil
within the impoundment areas.However,this option
must be limited by the need to prevent fines from being
entrai ned by surface water flow.Thus 1ocat ions for
spoil disposal within the impoundment areas must be
carefully selected and clearly designated in areas
which will quietly pond during filling,well away from
turbulent flows associated bed with intake structures.
Approximately 10 mcy of material will be required from
Borrow Area D for construction of the impervious core
of the Watana dam.Wet-processed spoi 1 from Borrow
Area D will be deposited on relatively flat sites
within the impoundment area away from the diversion
tunnel intakes and main intake approach channel
(Exhibit F,Plan F4).Exact locations of spoil
di spa sal areas withi n the Watana impoundment wi 11 be
determined during detailed engineering design.Prior
to the start of filling in 1991,and while the
cofferdams and diversion tunnels are operative,fines
will be sequestered by temporary construction berms.
However,protection from entrainment during diversion
and filling will be provided by locating spoil disposal
sites away from areas of turbulence or high-velocity
currents,and not solely by berms or other temporary
construction measures.
The approximately 28 mcy of spoil produced by dragline
mi ni ng and process i ng of materi a 1 from borrow areas E
and I will be disposed of within the excavation limits.
It is expected that the mined areas .of these sites will
pond at ri ver 1evel (1420-1440 feet,430-436 m)pri or
to construcfion of the Devil Canyon dam,and that a
larger area pool will form at reservoir level (1455
feet,441 m)following Devil Canyon development.The
pool area will depend on act!Jal :excavation limits.A
conceptual drawing of the pool is provided in Figure
E.2.25.
During excavation of borrow areas E and I,spoil will
be deposited temporarily in the vicinity of the gravel
processing plants,generally along the northern peri-
meter of excavation at any given stage in mining.The
fines will be contained by temporary construction berms
or in temporary pits.Permanent deposition will be
E-3-267
3.4 -Mitigation Plan
above the estimated 50-year flood 1evel of about 1473
feet (442 m).During filling of the Devil Canyon
reservoi r s the deposited fi nes wi 11 be covered with
vegetation slash and debris produced during reservoir
clearing.A more detailed description of construction
methods--including spoil disposal s siltation control s
and site rehabilitation--to be employed at borrow areas
E and I will be submitted in March 1983 as part of a
suppl ement to the Susitna Hydroel ectric Project
Feasibility Report.
Borrow Area G will be excavated between 1995 and 2000
as a source of concrete aggregate for construction of
the Devil Canyon dam and ancillary facil ities.This
borrow area is a first-level terrace site on the south
side of the Susitna Rivers occupying the area between
Cheechako Creek and the Devil Canyon damsite.The ter-
race elevation ranges from about 925 to 1175 feet (280
to 356 m).Aggregate will be processed on the site and
spoil deposited in the vicinity of the processing
plants which will change as excavation proceeds.
Excavation spoil from construction of the Devil Canyon
saddl edam wi 11 be haul ed or transported by conveyor
belt and al so deposited in Borrow Area G.Fi nes will
be sequestered in bermed cells within excavated
portions of the borrow area above the diversion tunnel
intake elevation of 870 feet.Spoil will not be
inundated until blockage of the diversion tunnel at the
start of reservoir filling in 2001.All of Borrow Area
G and spoil deposited therein will be entirely
inundated by the Devil Canyon reservoir and will lie
about 500 feet (151 m)below the surface elevation of
1455 feet (441 m).
Access road constructi on is not expected to produce
non-usable spoil requiring separate disposal sites.
Geotechnical alignment studies will be conducted during
detail ed engi neeri ng desi gn to provi de data necessary
to avoid ice-rich soils.Road construction will
utilize materials which allow side-borrow and balanced
cut-and-fill techniques which generate no excess
spoil •
In summarys vegetation removal will not be required for
major spoil disposal during construction of the Susitna
Hydroelectric Project.Spoil produced during the
Watana and Devil Canyon developments will be deposited
in the impoundment areas in a manner which will avoid
entrainment during construction or operation,and
entirely inundated.This mitigation measure is in
agreement with a recommendation of the USFWS (1983).
E-3-268
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3.4 -Mitigation Plan
Access road constructi on is not e.xpected to produce
excess spoil.
Construction of the 42-mile (67 km)transmission
corridor from Watana to the Gold Creek switching
station will occur from 1989 through 1992 (Figures
E.3.37-40 and E.3.81-82).This corridor will consist
of a right-of-way 300 feet (91 m)in width with two
parall el 1i nes of towers spaced 115 feet (35 m)apart
from centerline to centerline,and with tower-to-tower
spans of 1200 to 1300 feet (364 to 394 m)(Fi gure
E.3.85).During this construction,the Anchorage-to-
Fairbanks transmission corridor (including the Willow-
to-Healy intertie)will be widened to accommodate an
additional single-tower right-of-way 190 feet (58 m)
wide.The al ignment of the added right-of-way may
depart from the previously established corridor in
locations where constraints of land ownership,
environmental features,or aesthetics are present.
From 1999 through 2001,an 8-mile (13-km)corridor will
be built from the Devil Canyon damsite to Gold Creek
switching station.This additional corridor will con-
sist of two parallel lines of towers adjacent to the
previously constructed Watana-to-Gold Creek
configuration,requiring the right-of-way to be widened
to 510 feet (155 m)to accommodate the towers four
abreast.At that time,the Gold Creek-to-Anchorage
transmission corridor will be widened by 190 feet (58
m)to accommodate an additional line of towers.Thus,
with constructi on of the Watana and Devil Canyon dams,
two lines of transmission towers will extend from Gold
Creek to Fairbanks,and three lines of towers from Gold
Creek to Anchorage.A more detailed description of the
transmission corridors and their selection is provided
in Chapter 10,Section 2.4.
At the start of Watana development in 1985,a 69 kv
service transmission line will be constructed along the
Denali Highway-to-Watana access road.This line will
be constructed using conventional utility poles and re-
moved in 1994 or 1995 upon commissioning of the Watana
facility.Clearing of vegetation is not anticipated
for construction or maintenance of the temporary ser-
vice line.
The areal extents of vegetation types potentially to be
affected by the Susitna project transmission corridors
are summarized in Tables E.3.79,80,and 86.It should
be noted that these areas may change to a limited ex-
tent as al ignments are refined during detailed engi-
E-3-269
3.4 -Mitigation Plan
neering design and construction planning.It is fur-
the r emphas i zed that these quant it i es do not i nd i cate
areas of vegetation which will actually be removed by
transmission corridor construction and maintenance.In
fact,as stated i~Sections 3.3.4(a)and 3.3.6(a)(iv),
the 18,040 acres (7300 hal requi red for transmission
corridor rights-of-way will be cleared only to a 1 im-
ited extent,as explained in the following discussion.
The Power Authority has developed a mitigative approach
for constructi on and mai ntenance of transmi ssi on cor-
ridors in Alaska.Much of the following description is
presented in the Power Authority's environmental as-
sessment report for the Anchorage-Fai rbanks transmi s-
sion intertie (Commonwealth Assoc.1982),an integral
part of the Su sitna transmi ss i on system.However,
clearing limits apply specifically to the Susitna
proj ect.
Surveyi ng wi 11 be requ i red along ri ghts-of -way to lo-
cate centerlines and transmission tower positions.The
survey work will "involve limited cutting of trees and
shrub vegetation for line-of-sight staking and distance
measuring.No roads will be established during survey-
i ng.
Clearing of rights-of-way will be done selectively,
with typical clearing limits as shown in Figure E.3.85.
The illustrated cl eari ng 1 imits woul d appl y to guyed
X-type towers up to 85 feet (26 m)tall on level ter-
rain.Detailed criteria for different types and
heights of towers and for differing terrain wi11 be
prepared during detailed engineering design.In gen-
eral.cleaning will be limited as follows:
-The maximum height of vegetation on the inside buffer
edge will be 10 feet (3 m).
-The maximum height of vegetation on the outside buf-
fer edge will be 60 feet (IB m).
- A corridor of vegetation not exceeding 10 feet (3 m)
in height will be maintained between the transmission
lines except at tower sites.
-At tower sites,transverse strips 30 feet (9 m)in
width will be cut through to adjacent lines.
-Tower-to-tower span wi 11 be 1200 to 1300 feet (364 to
394 m).
E-3-270
f"C7 ,
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I
I
3.4 -Mitigation Plan
-The area under the lines,including 5 feet (1.5 m)
beyond the outside phases,will be clear cut to
within 6 inches (15 cm)of ground level,with growth
under 24 inches (62 cm)left in place.
-At tower sites and in areas occupied by access trails
(described below)or temporary construction facili-
ties,all vegetation may be cut.Grubbing of stumps
and stri ppi ng of the organi c surface 1ayer will be
required for tower erection in some cases.
The above clearing limits will apply only to vegetation
within rights-of-way.Outside rights-of-way,there
will be additional,1 imited clearing to remove danger
trees and to allow access (described below).Danger
trees are trees located outside the clearing 1 imits
which are of sufficient height to come in contact with
towers,guys,or 1i nes if the tree were to fall.Such
trees will be located,flagged,and felled by hand
tools or portable power saws,then hauled into the
right-of-way for disposal.Special permission will be
requested of landowners or land management agencies to
allow removal of danger trees.
Clearing of vegetation will be done by Hydro-axe,
v.ehicle-mounted shears,and hand-held power saws.Add-
itional equipment,including bulldozers,will be used
to stockpi 1e sl ash and debri s withi n ri ghts-of-way
prior to burning.The stockpiled vegetation will be
allowed to dry through the summer immediately follo.wing
clearing and control-burned under constant supervision
at the end of the summer.Bl1rning'wHl n.elp to reduce
the potential for spread of spruce budworm and other
insects.
The Power Authority intends that ground access be used
for construction and maintenance of the transmission
corri dors.The use of helicopters for these pu rposes
has been carefully con~idered,because it is recognized
that this option would reduce requirements for access-
related clearing of vegetatiion and thus serve a signif-
icant mitigative function.However,the limitations of
helicopter use include high cost,limited load-carrying
capacity,weather-related restrictions,daylight use
only (particularly during winter months),and-unaccept-
able safety risks ;n the vicinity of high-voltage lines
and guyed towers.
Construct i on and mai ntenance contractors will be re-
qui red to prepare access pl ans acceptable to the Power
E-3-"2:71
3.4 -Mitigation Plan
Authority and controlling agencies or landowners.Min-
imizing requirements for clearing of vegetation will be
an important criterion for the eval uation and approval
of these plans.Basic elements of access planning will
i ncl ude:
-Stipulation that existing roads must be used to the
nearest point of transmission corridor access;
-Permission for contractors to build construction
trails from the nearest points on existing roads to
the rights-of-way;
-Stipulation that construction trails be established
only after thorough onsite assessment of alternative
routes and procedures to ensure minimal environmental
disturbance,including avoidance wherever feasible of
dense vegetation,stream crossings,wetland and
floodplain areas (identified with the concurrence of
the CDE and USFWS),and extens i ve switchbacks on
steep,erosion-prone terrain;and
-Use of l11i nimum standard trail s from tower to tower
along the inside cleared portions of the rights-of-
way.
For construction of the Watana-to-Gold Creek transmis-
sion corridor during 1989-1992,the connecting road
between the two dams ites wi 11 be bui It as pl anned and
maintained year-round.Construction trails from the
mai n access road to the ri ghts-of-way wi 11 be cl eared
along approved alignments.Because use of the con-
struction trails will be limited to flat-tread or
balloon-tire vehi~les,fill placement or removal of the
o rg an ic 1aye r will not be requ ired.From the south
bank of the Susitna River to Gold Creek switching sta-
tion,the railroad extension right-of-way will be de-
veloped as a minimum-standard (approximately 20 feet or
6 m wide)road to support transmission corridor
construction.Equipment access to Gold Creek switching
station will be provided along the intertie right-of-
way.
It is anticipated that maintenance-related clearing of
transmission corridor rights-of-way will be necessary
approximately every 10 years.During ,interval s between
periodic clearing,vegetation within the rights-of-way
will be allowed to grow without disturbance,except for
the occasional removal of danger trees as required,or
E-3-272
3.4 -Mitigation Plan
localized clearing associated with tower and line main-
tenance or repair.It is the established policy of the
Power Authority that herbicides are not used for any
aspect of transmi ss i on corridor construction or mai n-
tenance.
The selective clearing of transmission rights..,of-way
wi 11 result in enhanced browse producti on associ ated
with sprouting and succession.Clearing will thus aug-
ment other measures to compensate for proj ect-re 1ated
loss of browse,as discussed in Section 4.4.2{b).Fur-
ther benefit will be derived by goshawks,sharp-shinned
hawks,and other raptors and owls which will hunt along
the rights-of-way as discussed in Section 4.3.4(c).
These benefits must be weighed against the potentially
adverse effect of increased pub 1 ic access whi ch
portions of the rights-of-way may provide.The issue
of increased access is discussed in Sections
3.3.1{b)(v)and 4.3.3,and below in Section 3.4.2(b).
On-ground evaluations will be made during detailed
engineering design and construction planning regarding
appropriate management procedures for specific portions
of the transmission corridors (e.g.,the extent of
clearing,maintenance requirements,and potential
seeding of areas disturbed during construction).These
site assessments will be conducted in coordination with
representatives of the USFWS,the ADF&G,and the Alaska
Plant Materials Center,as recommended by the USFWS
(1983)•
Access to transmission corridors has been coordinated
closely with access along roads,the railroad
extension,and already existing adjacent transmission
corridors,as recommended by the USFWS (1983),the
Susitna Hydroelectric Steering Committee (1981)and the
EPA (1981).Policies on public access during and after
construction and along the length of the corridors will
be consistent with management policies of agencies and
landowners with jurisdiction over the properties
traversed by the corridors.
E-3-273
In summary.the direct removal of vegetation as a
result of transmission corridor construction and
mai ntenance will be mi nimi zed through the appl i cat ion
of selective clearing techniques which will remove only
vegetation that might impede access.construction,or
maintenance of the transmission system..Vegetation
removal will be minimized further by constraints
imposed on the routing of access trails to the
rights-of-way.and especially by alignment of the
Watana-to-Devil Canyon access road and transmission
right-of-way together along a common corridor.
Herbicides will not be used.Selective clearing
repeated approximate 1y every 10 years will enhance
browse and hunting habitat for moose and certain
raptors,respectively,'by maintaining cleared portions
of the rights-of-way in early successional stages.
The Power Authority will apply all of the minimization
measures descri bed above to mit i gate impacts of
vegetation removal during construction and operation of
the Susitna Hydroelectric Project.These measures will
begin with potential FERC licensing and scheduled
construction startup in 1985,and continue through the
50-year license period to 2035.
Minimization of vegetation removal will affect a sig-
nificant area and make an important ~ontribution toward
mitigating the cumulative impact of the Susitna project
on vegetation.The precise areal extent of vegetation
cover saved from removal cannot be quantified
defensibly until detailed engineering designs and
construction plans are formulated,and even then,only
on a provisional basis.However,some examples can be
provided as follows.
Of the approximately 66,679 acres (26,995 ha)potenti-
ally subject to vegetation removal on a cumulative'
basis,about 30 percent,or 19,236 acres (7788 ha),
will allow application of the mitigation measures de-
scri bed above.Approximately 46 percent of th-e total
area covered by transmission corridors (7444 acres
[2978 ha]of the total 16,182 acres [6473 ha])will be
left uncleared or partly cleared.In addition,use of
side-borrow and balanced cut-and-fill techniques for
construction of the access roads and railroad extension
will protect up to 280 acres (112 ha)of vegetated
a rea.
[-3-274
3.4 -Mitigation Plan
Using the two examples cited above,measures to
mi nimi ze vegetation remova 1 will conserve about 7724
acres (3127 hal,or up to about 40 percent of the land
area in question.If spoil produced by processing of
borrow materi al needed for dam constructi on were
deposited outside borrow area excavation limits or
outside the impoundment areas,additional vegetation
would be removed or burned.For example,deposition of
spoil from borrow areas E and I to a depth of 3 feet
(.09 m)would cover 5782 acres (2341 hal.
-
(i n
Although the quantities in these examples must be con-
sidered hypothetical at the present stage of design,it
is nevertheless evident that measures to minimize vege-
tation removal will have an appreciable mitigative ef-
fect on the cumulative impact of project construction
and ope rat ion.
Rectifi cat i on
Certain ancillary project facilities will be required
on a tempora ry bas is duri ng con struct i on and vacated
when construction has been completed.Vegetation
removal resulti ng from development.and use of these
facilities can be partially rectified by dismantling
the structures,rehabil itat i ng the underlyi ng soil s,
and preparing the soil s to allow reestabl ishment of
vegetation.These options will be followed to rectify
effects of vegetati on removal duri ng constructi on of
the Watana and Devil Canyon dams..
Lands associated with the following temporary
facilities will be rehabilitated in accordance with the
schedules shown:
E-3-275
3.4 -Mitigation Plan
WATANA
Facility &
Vegetation Action Year Area
(acres)
Construction Camp Start Const.1985 78
-Bi rch Shrub Complete Const.1986 78
-Mixed Low Shrub Dismantle &Reclaim 1994 78
Dismantle &Reclaim 1995 78
Vill age Start Const.1986 86
-Birch Shrub Complete Canst.1987 87
-Mixed Low Shrub Dismantle &Reclaim 1994 86
Construction Roads Start Const.1985 120
-Closed Birch
Forest Continue Canst.1986 120
Closed Mixed
Forest Complete Const.1987 60
-Open Mi xed
Forest Grade &Reclaim 1994 150
-Closed Tall
Shrub Grade &Reclaim 1995 150
-Mi xed Low
Shrub
Contractor Work
Areas Start Const.1985 190 r--
-Closed Bi rch
Forest Continue Con st.1986 360
-Closed Mixed
Forest Complete Const.1987 190
-Open Mixed
Forest Dismantle &Clear 1994 740 ~.-Closed Tall
Shrub Grade &Reclaim 1995 370
-Mixed Low
Shrub Grade &Reclaim 1996 370
E-3-276
E-3-277
3.4 -Mitigation Plan
DEVIL CANYON (CONT.)
Facility &
Vegetation Action Year Area
(acres)
Contractor
Work Areas Start Const.1994 150-Open Bl ack
Spruce Fo rest Continue Canst.1995 150
-Closed Bi rch
Forest Continue Const.1996 150
-Open Mixed
Forest Comp 1ete Con st.1997 30
-Closed Mixed
Forest Dismantle &Clear 2002 480
Grade &Reclaim 2003 480
Borrow Area K Excavate 1995 100
-Open Black
Spruce Forest Excavate &Reclaim 1996 100 &100
-Closed Mi xed
Forest Excavate &Reclaim 1997 100 &100
-Closed Tall
Shrub Excavate &Reclaim 1998 65 &100
-Lake Reclaim 1999 65
TOTAL REHABILITATED AREAS--
-Watana 1986-1996 2079
-Devil Canyon 1996-2003 1130
-Total 1986-2003 3209
Rehabil itation of temporary faci 1ity sites wi 11 only
partially rectify the vegetation loss resulting from
their construction.Provided soils are restored,plant
succession will proceed at various unquantifiable rates
depending on slope,aspect,elevation,soil types,
moisture and drainage conditions,and other factors.
Without restoration of mineral and organic soils,
recovery of forest and shrubl and withi n the proj ect
area would require 150 years at the very minimum
(McKendri ck 1982 personnel communi cati on.Therefore it
may be assumed that some semblance of the original
pattern of lost vegetation will be restored within 150
years on 1ands prepared for rehabil itat i on,but
predictions of how plant succession wi.11 proceed on
these lands over time would be difficult to justify.
E-3-278
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3.4 -Mitigation Plan
Because rehabil itation procedures for disturbed lands
in Alaska are best developed on a site-specific basis
(Brown et ale 1978),preparation of a comprehensive re-
storationPTan for the Susitna project has been desig-
nated as a task for the detailed engineering design
phase.An individual restoration plan will be devel-
oped for each area to be rehabilitated.The individual
plans will incorporate the following information for
use by rehabilitation contractors and monitors:
-Plan view (drawing)of area to be rehabilitated,with
limits clearly delineated along with overburden
stockpile locations and areas of special concern
(e.g.,erosion,slumping,oil saturation from equip-
ment maintenance shops,etc.);
-Aerial photographs of the area shown in the plan
view,to serve as a photo base for the following
overlays;
Overlays of original vegetation and soil types and
appropri ate revegetati on cl asses (Al aska Rural
Development Council 1977);
•Overlay of areas requiring special treatment (e.g.,
seeding for erosion control,waterbars,extra top-
soil,extra fertilizer application,etc.);
Specific locations for the stockpiling of organic
overburden,with special protective measures against
drying,wind erosion,and runoff;
-Specific depths and procedures for ripping and scari-
fication during soil preparation;
-Specific quantities and types of fertilizers to be
applied;and
-Specific revegetation mixtures to be used for
seeding,with application rates (lbs/acre)and
methods (drilling or hand broadca~ting).
In general,the following procedural overview gives an
indication of the approach which will be used for site
rehabilitation,based on experience from other projects
i nvol V"j ng non-arcti c i nteri or regi ons of Al aska (for
example,see Pamplil'l 1979).However,specific
restoration plans will provide much greater detail,as
described above.
E-3-279
3.4 -Mitigation Plan
The 1 and su rface of di stu rbed a reas wi 11 be ri pped
prior to application of topsoil,then graded to contour
and evenly covered with organic overburden and topsoil
previously stockpiled for this purpose.Fertil izer
high in phosphorus (e.g.,10-20-10 or 8-32-16,N-P-K)
will be applied at a rate sufficient to supply 85 to
110 kg of nitrogen per hectare.
Following the spreading of organic overburden,topsoil,
and fertilizer,the site surface will be scarified to a
depth of 12 inches (40 cm)usi ng a rake towed by a
mi ni -Roll i gon type vehi cl e.Thi s procedure wi 11 mi x
the organics with the underlying mineral soil,aerate
the mixture,and 1 ight1y compact the surface.During
the second and third growing seasons,fo1lowup applica-
tions of fertilizer will be made at one half to
one third the original rates.
Where erosion potential or aesthetic considerations can
be demonstrated not to be involved,site rehabilitation
wi 11 emphasi ze app1 i cati on of organi cs and nutri ents
and minimize seeding.The USFWS (1983)concurs with
this approach,which will encourage the reinvasion of
native species from the surrounding parent population.
For lightly disturbed sites with intact topsoil,
fertilization alone should be sufficient to facilitate
revegetation.
Sites with high erosion or visual impact potential will
be fertilized and seeded with fast-growing native
grasses appropriate to the climate and geography of the
Susitna Basin.To minimize erosion,all sites will be
rehabilitated by the first growing season following re-
moval of structures and equipment.Sufficient
quantities of seeds for sites requiring revegetation
will be stockpiled,and regrowth potentials of
available native strains will be tested prior to
project abandonment of distrubed sites.Choice of
plants for site rehabilitation will be made after
consultation with federal and state natural resource
agencies.This approach has been recommended by the
USFWS (1983).
Ins umma ry ,rect ifi cat i on will restore vegetat i on to
approximately 3209 acres (1299 ha)temporarily lost to
ancillary facilities.This represents about 5 percent
of the cumulative total land area affected by direct
loss of vegetation during project construction and op-
eration (68,537 acres,27,339 ha).
E-3-280
-3.4 -Mitigation Plan
Rectification will only be partial because of the long
periods (up to 150 years)required for plant succession
to preexisting conditions.Individual restoration
plans will stipulate detailed procedures to facilitate
revegetation on specific sites.Development of these
plans is a designated task .of the detailed engineering
design phase of the project.
-
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(i i i )Reduction
Options for the reduction of direct vegetation removal
over time involve monitoring project facilities and
activities to ensure the most effective use of
rehabil itation measures.Duri ng project construction
and operation,the following three tasks will be
performed on a continuing basis:
-Monitoring progress of site rehabilitation to ident-
ify locations requiring repeated or altered applica-
tion of fertilizer and/or seed;
Systematically identifying and rehabil itating areas
where construction activities have ceased and are no
longer required;and
-Coordinating rehabilitation efforts with closure and
removal of service or temporary access roads no
longer required.
These measures wi 11 be i ncl uded in the comprehensi ve
restorat i on pl an descri bed above in Secti on
3.4.2(a)(ii)and,in fact,will help to focus and
implement that plan.
In the construction zone of a large project,disturbed
areas partially or wholly without vegetation develop
with expansion of the infrastructure of temporary
roads,residential quarters,storage yards,equipment
maintenance shops,and other ancillary facilities.
Although areal extents have been quantified with
respect to camps,service roads,contractor work areas,
borrow sites,and other facilities,these
quantifications can only estimate the actual extent of
vegetation removal,because zones of activity will
surround these sites.Foot traffic and the movement of
vehi cl es and equi pment wi 11 tend to enl arge areas of
disturbance around centers of activity,despite the
consolidation measures described in Section
3.4.2(a)(iii).
E-3-281
3.4 -Mitigation Plan
One objective of monitoring is to maintain awareness of
disturbed areas as they enlarge or as activities
diminish,so that rehabilitation can begin as early as
feasible.Monitoring of vegetation removal during
construction will provide for the appl ication of
rehabilitation measures in locations other than or
adjacent to the areas specifically targeted in the
individual restoration plans,and on an as-needed basis
throughout the construction period.Monitoring of
vegetation loss will also be conducted during
pre-construction field activities and throughout the
license period to detect later disturbances quring
operation and maintenance.
The moni tori ng program descri bed above wi 11 be a com-
ponent of the project-wide monitoring plan to be estab-
lished formally during the detailed engineering design
and construction planning phase of the project (Section
1.3).
(iv)Compensation
By its very nature,a large hydroelectric development
such as the Susitna project will permanently remove a
considerable area of vegetation dedicated to the dam-
sites,impoundment areas,access routes,and permanent
buildings.For the Susitna project,the cumulative
area lost in thi s way wi 11 total about 45,581 acres
(18,454 ha),with 44,292 acres (17,932 ha)covered by
the impoundments.Actual acreages of vegetation types
which will be removed were discussed previously and
quantified in Tables E.3.83 and E.3.84.
From the preceding options analysis,it is evident that
measures for minimization,rectification,and reduction
of vegetat ion loss wi 11 apply,at most,to about 30
percent (19,236 acres,7788 ha)of the total area of
vegetation which will be removed by the project.Loss
of the remaining 70 percent can be mitigated only
through compensation.
Two compensation options have been considered to miti-
gate direct loss of vegetation resulting from project
constuction and subsequent operation:
-Acquiring lands with areal coverages of vegetation
types equivalent to those lost,and protecting the
lands from future development;and
E-3-282
-
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3.4 -Mitigation Plan
-Prioritizing lost vegetation types relative to value
as wil dl ife habitat,and then sel ecti vely alteri ng
vegetation on acquired lands to replace or exceed
lost areal coverages of the high-priority vegetation
types.
The second option descri bed above has been selected
because habitat enhancement measurs that alter
vegetation will allow compensation for loss of
high-priority vegetation types while requiring
relatively small areas of replacement land.
As indicated in the wildlife impact discussion (Section
4.3),impacts to moose,brown bear,and black bear
through habitat loss and alteration have received high
priority by project planners.Compensation for loss of
vegetation types important to these species will there-
fore be impl emented through habitat enhancement mea-
sures on replacement lands in the middle basin and
downstream from Gold Creek.A detailed description of
this program is provided in Mitigation Plan 6,Section
4.4.2(b).Costs and schedules for the program are pre-
sented in Section 4.4.3.
In conjunction with the ADF&G,the USFWS,and the
University of Alaska,the Power Authority is currently
devel opi ng a habitat-based model for moose carryi ng
capacity based on moose bi oenerget ic requi rements and
browse nutritional value.This program is described as
Nitigation Plan 7 in Section 4.4.2(b)and explained
further in Appendix 3.H.Vegetation studies now in
progress are providing data to support the model ing
program,as described below.
Inventories to quantify physical and nutritional char-
acteri st i cs of moose browse vegetation were conducted
in the project area during the summer of 1982,with
data analysis continuing through early 1983.A pl ant
phenology study focusing on spring green-up of riparian
vegetation along the Susitna River floodplain in the
middle basin also was conducted in 1982.Early green-
up of riparian vegetation may be an important nutri-
tional source for moose and bears,especially following
severe winters.Third"species distribution,abun-
dance,and percent cover of vegetation within a desig-
nated 6400-acre controlled burn area on Bureau of Land
M-anagement (BLM)1and in the Al phabet Hill s (east of
the project area)were quantified in 1982.This
program is being conducted in cooperation with the
E-3-283
3.4 -Mitigation Plan
'Institute of Northern Forestry of the National Forest
Service,the ADF&G,and BLM.As described further in
Mitigation Plan 6,Section 4.4.2(b),controlled burning
is scheduled for August 1983,provided suitable weather
conditions occur.Followup studies characterizing
post-burn plant succession will be conducted in the
future to hel p assess the suitabi 1 ity of controll ed
burni ng as a method for browse enhancement.It is
likely that burning woodland conifer forest will
produce a herbaceous or shrub stage (Foote 1979)
characterized by rapid nutrient turnover,high
productivity,and relatively high decomposition rates
(Viereck and Schandelmeier 1980).The resulting low
shrub stands will provide approximately a three-fold
increase in browse biomass (Table E.3.92,Figure
E.3.117).
Mapping of moose browse vegetation within the central
portion of the middle basin is currently planned.This
program,described in Section 3.2.2(a),will provide a
means for detailed quantification of browse loss inside
and browse availabil ity outside direct impact areas,
and facilitate application of the moose modeling
program to specific features of the project area.
Integrating the mapping and modeling efforts will allow
more accurate quantification of carrying capacity loss
resulting from the project and will also provide a
means for quantifying replacement land requirements.
The identification of replacement lands for habitat en-
hancement will place highest priority on state and fed-
eral lands which can be acquired at minimal or no cost.
Al aska Department of Natural Resources (ADNR)statutes
(Title 38)set forth provisions for exchanges of state-
owned lands on an equal-value basis following
appraisal.Because state-owned lands supporting black
spruce vegetation types with high enhancement potential
are readily available in the project vicinity,it is
anticipated that exchanges of state lands with ADNR
review and concurrence may provide an avenue for
acquisition of replacement lands.
A second avenue for replacement land acquisition is
provided by Section 907 of the Alaska National Interest
Lands Conservation Act of 1980 (Pub 1 i cLaw 96-487).
This provision establ ishes the Al aska Land Bank
Program,whereby tax incentives and other benefits are
E-3-284
-
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.-
3.4 -Miti gati on Pl an
afforded private landowners who make lands available
for management of fish and wi ldlife in accordance with
poli ci es of state or federal agenci es.
In summary,compensation for permanent vegetation loss
wi 11 be implemented through the acqui siti on of repl ace-
ment 1ands to be managed for browse habi tat enhance-
ment.Vegetati on studi es and mappi ng are bei ng con-
ducted to support habitat-based modeling of moose
carrying capacity.Modeling results will in turn be
used to quanti fy project-rel ated loss of carryi ng ca-
p aci ty and requi rement s for replacement 1and acqui si -
tion.Costs and schedules for elements of these pro-
grams are summarized in Sections 3.4.4 and 4.4.3,and
in Tables.E.3.177 and 178.
-
""'"
-
(b)Indirect Loss of Vegetation
Vegetation loss will result from slope instability effects
during and after fi lling of the impoundment areas (Sections
3.3.1,3.3.2,and '3'.3.6(b)).As reservoir soi ls become sat-
urated and slopes settle to new angles of repose,slumping
and landslides wi 11 occur above and below surface levels.
Erosion and slumping wi 11 result from melting of permafrost,
particularly along the south side of the Watana impoundment
where deep permafrost occurs (Section 3.3.l[b][iiJ).These
effects will be intensified in the Watana reservoir by the
yearly peri odi c freezi ng,thawi ng,saturati on,and dessi ca-
ti on of soi 1s wit hi n the 90-foot (27-m)drawdown zone,by
hydrauli c erosi on,and by ice formati on.Al though preci se
areal extents and elevation ranges of these effects cannot
be reliably quantified in advance,the following areas will
be susceptible to vegetation loss (Duncan 19B3personal com-
muni cati on).
-The lO-mi le (16-km)reach from the headwaters of the
Watana reservoi r (RM 243)to the Oshetna Ri ver-Goose Creek
area (RM 233),where c li ffs of frozen si lt sand clays
occur.Predomi nant vegetati on types borderi ng the i m-
poundment area in this reach are woodland black spruce and
birch shrub (~gure E.3.65).
-The 49-mi le (78-km)reach along the south si de of the
Watana reservoi r from the Oshetna Ri ver-Vee Canyon area
(RM 233-225)to the Watana damsi te (RM 184).Thi s reach
is underlain by 200-to 300-foot deep (60-to 90-m)dis-
conti nuous permafrost.Predomi nant vegetati on along the
reservoir margin is woodland and open black spruce and low
shrub types (Figures E.3.65-61).
E-3-285
3.4 -Mitigation Plan
-The lO-l11i le (16-km)reach along the north side of the
Watana reservoir between the Watana Creek area (RM 194)
and the Wat ana damsi te (RM 184).Thi s reach is
characterized by unconsolidated glacial outwash,much of
it in the 9-foot (27-m)drawdown zone.Predomi nant
vegetation types types along the northern reservoir margin
in thi s reach are wood 1and and open black spruce,bi rch
shrub,and mixed low shrub (Figures E.3.62-61).
-An old landslide area on the south side of the Devi 1 Can-
yon impoundment at RM 175,about 2 mi les (3.2 km)down-
stream from the mouth of Fog Creek (RM 177),and 9 miles
(14.4 km)downstream from the Watana damsite (RM 194-184).
Aeri al photographs show thi s locati on as forested;and
Figures E.3.61 and 60 indicate that woodland and open
black spruce,open white spruce,and open mixed forest are
the predominant vegetation types.
It is evident that vegetation loss from slope instability,
erosion,and blowdown along the reservoir margins wi 11
produce a cumulative impact in addition to the direct losses
described in Section 3.4.2(a).However,the precise
vegetation types,locations,areal extents,and elevation
ranges whi ch wi 11 be affected by these i ndi rect losses
cannot be reli ably quanti fi ed in advance.~Ji thout alteri ng
fi xed characteri sti cs of the dams and reservoi rs,there is
no way to avoid,minimize,rectify,or reduce these impacts.
Loss of low shrub vegetation,important for browse and berry
production,wi 11 be compensated for by the land acquisition
and habitat enhancement programs described in Sections
3.4.2(a)(iv),4.4.2(b),and 4.4.3.
Additional indirect losses of vegetation will result from
increased human acti vi ty wi thi n the project area duri ng con-
struction and operation (Sections 3.3.1(b)(v),3.3.3(a)and
(b),3.3.4(a)and (b),and 3.3.6(b).Nonessential distur-
bances to vegetation and soi ls by construction workers can-
not be avoided entirely,but substantial minimization will
be possible through consolidation of facilities and careful
planning of traffic patterns and service roads (Section
3.4.2(a)(i)).Parti cul ar attenti on wi 11 be gi ven to i nfra-
structure 1ayout duri ng detai led engi neeri ng desi gn and con-
struction planning,including design participation and
r evi ew by proj ect envi ronment a 1 speci ali st s.
Thoughtful planning and implementation of an environmental
briefings program requiring the participation of all field
personnel wi 11 make an important contribution towards mini-
mi~ng unnecessary disturbances to soi 1 and vegetation dur-
ing project construction and operation (Appendix 3.B).
E-3-286
"""
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3.4 -Miti gati on P1 an
Recti fi cati on and reducti on of vegetati on losses,resulti ng
from acti vi ti es of constructi on workers,wi 11 be
accomplished through the rehabilitation and monitoring
programs described in Sections 3.4.2(a)(ii)and (iii).
Increased human activity on public lands surrounding the
project (discussed also in Exhibit E,Chapter 5 -Socio-
economics ..and Chapter 7 -Recreation)could be greatly
dimi ni shed by fenci ng and gati ng access roads and transmi s-
si on corri dors.However,even wi th these measures,access
would sti 11 be avai 1able by off-road vehi c1e (ORV)or all-
terrain vehicle (ATV)from the Parks and Denali Highways and
through the use of smallai rcraft.Moreover,fencing along
the lengths of access routes and transmi ssi on corridors
would block free passage of big game.
During construction of the Watana and Devi 1 Canyon projects
(1985-2002),pub1i c access along the Denali Hi ghway-to--
Watana road wi'll be restricted by use of a locked gate
supervi sed by security guards.Pub1i c use of the Gold
Creek-to-Devi 1 Canyon rai 1road extensi on wi 11 not be avai 1-
able.These measures will largely avoid increased impacts
to vegetati on resu1ti ng from recreati ona1 users and others
attracted by the project duri ng constructi on.It should
agai n be noted,however,that restri cti ng access along the
Denali Hi ghway-to-Watana road wi 11 not necessari 1y deter or
diminish the existing pattern of access by ORV and ATV from
the Denali Hi ghway,Parks Hi ghway,and Gold Creek onto
public and private lands surrounding the project.
Vegetation loss and soi 1 damage from public access-related
vehicle use wi 11 occur following construction and throughout
the license period (2003-2035)and may inten~fy over time
as popu1 ation growth and recreati ona1 and hunti ng pressures
increase (see Exhi bit E,Chapter 7 -Recreati on).ORV and
ATV use already is occurring on lands surrounding the proj-
ect and has resulted -j n obvi ous soi 1 damage and vegetati on
loss,as shown in Exhibit E,Chapter 8 -Aesthetics,Photos
8.D.5 and 8.D.6.
Increased pub li c access as an i ndi rect consequence of the
project cannot be entirely avoided by the Power Authority
because access to lands surrounding the project is avai 1ab1e
through ORV,ATV,and ai rcraft use,as noted above.The
project access route does,however,avoid areas south of the
Susitna River (Stephan Lake,Prairie Creek,Fog Lakes,as
well as the Indi an Ri ver area)-which are valuable as wi 1d-
life habitat in keeping with recommendations of the Susitna
Hydroelectric Steering Committee (1981).
E-3-287
3.4 -Mitigation Plan
Options to minimize access-related impacts during the
postconstructi on peri od include gati ng on the Denali
Hi ghway-toWatana road to restri ct access,use of si gns to
deter vehicle departures from the road,speci a1 regulatory
desi gnati on of the access route to di scour age ORV and ATV
use,and consolidation of access-related activities through
design of the project recreation plan.
Policies governing public access to the project area during
the postconstruction years of the license period are
currently under consideration.Such policies will require
agreement among the 1 and and resource management agenci es
and private landowners with jurisdiction over lands
surroundi ng the project.Access-re1 ated measures of the
Power Authority wi 11 conform with those policies.
A variety of regulatory options are available for reducing
human acti vi ty on pub 1i c 1 ands in the project area.For
example,the ADF&G (1983)has noted that me'asures may be
taken by the Boards of Game and Fisheries and by the
Commi ssi oner of Fi sh and Game to re1i eve hunti ng and fi shi ng
pressures (see Secti on 4.4.l[b]).These opti ons inc 1ude
enti rely c10si ng an area to hunti ng and fi shi ng or creati ng
a speci a1 use area where motori zed vehi c1es are prohi bited
from hunti ng.Because hunti ng and fi shi ng are the primary
reasons for use of motorized vehicles within the project
area,such measures could substanti ally change user
patterns.
Si gns may be used to deter road users from dri vi ng thei r
vehicles off the access road onto surrounding terrain,pos-
sibly in conjunction with special regulatory designation.
For example,the Denali Hi ghway is under revi ew by the BLM
for inclusion in the National Scenic Highway System (Ward
and Wr abetz 1982 personal communi cati on).The project
access route may also be eligible for this designation,
which would entail restrictions on off-road vehicle use and
other potenti ally di sturbi ng acti viti es i niti ated from the
access road.However,thi s measure would also attract
people to the project area.
The Susitna Hydroelectric Project Recreation Plan is pre-
sented in Exhi bit E,Secti on 7.A major objecti ve of the
Recreati on P1 an is to est ab 1i sh patterns of pub li c access
that will minimize and localize access-related impacts
through the use of trai 1sand desi gnated campi ng area.The
Recreati on P1 an is consi stent wi th fi sh and wi ld1i fe habi tat
protecti on pri ori ti es estab 1i shed for the project.In addi-
ti on,the phased desi gn of the Recreati on P1 an wi 11 ensure
E-3-288
~--~',
,~
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3.4 -Mitigation Plan
that implementation will be gradual and based on monitoring
of fish,vegetation,and wildlife impacts as well as
recreati onal user needs.Implementati on of each phase wi 11
be subject to interagency review and concurrence.
In summary,vegetati on loss resulti ng from i nstabi li ty along
the margins of the impoundment areas and from increased pub-
lic access to lands surrounding the project will produce a
cumulative impact augmenting the impact of direct construc-
tion-related vegetation removal.Loss of shrubland browse
speci es wi 11 be compensated for by acqui si ti on of repl ace-
ment lands and habitat enhancement measures,as described in
Sections 3.4.2(a)(iv)and 4.4.2(b).Vegetation loss result-
i ng from increased pub li c access wi 11 be mi ni mi zed by con-
fi ni ng access routes to areas north of the Susi tna Ri ver,
use of signs and possibly of speci al regulatory designation
to discourage ORV and ATV use,and by phased implementation
of the project Recreati on Pl an wi th interagency revi ew and
concurrence.In additi on,a vari ety of regul atory opti ons
are avai 1ab 1e to resource management agenci es to li mi t
access on public lands under their jurisdiction.
(c)Alteration of Vegetation Types
Alterati on of vegetati on types wi 11 be caused by pl ant suc-
cessi on,changes in drai nage patterns,regul ated downstream
flows,and fi reo Pl ant successi onal changes wi 11 occur
along the margi ns of the impoundment areas as a result of
the slope instability processes described in Section
3.4.2{b).Because such changes cannot be quantitati vely
predicted and because they wi 11 involve an increase in pro-
ductive early-successional stages of value as browse or for-
age,speci al mitigative measures are not planned.
Potenti al changes in surface drai nage patterns are of
greatest importance where wetland areas are involved.Under
Army Corps of Engineers regulations promulgated by Sections
301 and 404 of the Clean Water Act (33 USC 1344),wetlands
are defi ned as "those areas that are inundated or saturated.
by surface or ground water at a frequency and durati on to
support,and that under normal ci rcumstances do support,a
prevalence of vegetation typically adapted for life in
saturated soi 1 condi ti ons ll (33 CFR 323.2[c]).
As explained in Section 3.2.3,potential wetlands of the
impoundment borrow areas and of the access corri dors were
mapped using the system of Cowardin et ala (1974),as adop-
ted by the USFWS (1980).Further mappi ng is bei ng i ni ti ated
at a scale of 1:250,000 and will delineate wetland vegeta-
E-3-289
3.4 -Mitigation Plan
tion types to classification Level IV of Viereck,Dyrness,
and Batten (1982).Preliminary mapping wi 11 be avai lable in
June 1983 pri or to fi eld confi rmati on duri ng June through
October 1983.It is expected that thi s mappi ng wi 11 provi de
a det~led and accurate representation of wetland vegetation
types within the project area at a scale and resolution
sati sfactory for Secti on 404 permit eval uati on by the COE in
coordination with the USFWS.Two meetings with representa-
tives of these agencies were held in December 1982 to review
and define plans for the mapping and to initiate consulta-
tion for the purpose of Section 4 permit application plann-
i ng.
It is not anticipated that the Susitna Project will produce
major impacts on wet 1ands out si de the impoundment areas.
Two locations of concern have been identified:
(1)The 14-mi le (22-km)porti on of the Denali Hi ghway-
to-Watana access route (MP 24-38)passi ng near the
Deadman Creek drainage (Figures E.3.80-81);and
(2)The Jack Long Creek area (Fi gure E.3.82).
Major impacts to wetlands in these areas wi 11 be avoided by
the routing changes and special siting and construction pro-
cedures descri bed in Secti on 3.4.2(a)(i ).
During detailed engineering design and construction plan-
ni ng,coordi nati on wi th the COE and USFWS wi 11 conti nue so
that i ncorporati on of proper engi neeri ng desi gn to mi ti gate
for potenti al drai nage alterati ons is assured.The hi gh-
resolution wetlands mapping,along with color aerial photo-
graphs,wi 11 be an important tool in thi s regard.Proper
engineering design and construction planning for wetland
areas are considered to be a top-priority component of the
project civi 1 engineering program.
During detailed alignment studies for the transmission
corri dors,project engi neers,hydrologi sts,and
environmental specialists will inspect the corridors from
the ai r and ground and make si te-speci fi c ali gnment
adjustments to minimize wetland and floodplain crossings.
No fill placement will be associated with transmission
corridor construction.
As explained in SectiDn 3.3.l(b)(iii),regulated flows wi 11
produce changes in vegetati on di stri buti on and successi onal
patterns in the downstream floodplain.These changes wi 11
E-3-290
,-rG---
.....
,....
.....
3.4 -Mi ti gati on Pl an
be monitored during the postconstruction years of the
li cense peri od in conjuncti on wi th ongoi ng studi es of moose,
raptors,and other wildlife by the ADF&G and the USFWS.
Downstream aeri al photography of the fl oodpl ai n wi 11 be
conducted at ten-year intervals beginning in 1988 to
document and facilitate analysis of floodplain configuration
and vegetati on changes in coordi nati on wi th hydrology and
wi ldli fe moni tori ng.
The effect of fi re as a natural process in regul ati ng
patterns of plant succession was discussed in Section
3.3.1(b)(v).Fi re control wi 11 be the responsi bi lity of
resource man agement agenci es wi th juri sdi cti on over pub 1i c
lands of the project area.The BlM wi 11 be responsible for
control measures associated with the Alphabet Hi 11s burn
(Sections 3.4.2[a][iv]and 4.4.2[b]).-Plans and procedures
for subsequent controlled burning by the Power Authority as
a habitat-enhancement measure wi 11 be closely coordinated
wi th BlM.
In summary,the hi ghest pri ori ty and greatest effort wi th
respect to mitigation of project-related changes in vegeta-
ti on wi 11 be in regard to wet 1ands.Detai led engi neeri ng
desi gn and constructi on pl anni ng wi 11 be coordi nated wi th
the COE and USFWS representatives as part of the Section 404
planning process.
3.4.3 -Mitigation Summary
As discussed in Section 3.4.2,project impacts to vegeta-
tion wi 11 be important mainly from the standpoint of loss
of wi ldlife habitat.Therefore,mitigation plans for
botanical resources have been determined primari ly to sup-
port the wi ldlife mitigation program.Major mitigation
plan elements described in Section 3.4.2 are:
(1)Mi ni mi zi ng faci lity di mensi ons.
(2)Consoli dati ng structures.
(3)Siting facilities in areas of low biomass.
(4)Siting facilities to minimize clearing of less abun-
dant vegetati on types.
(5)Siting facilities to minimize clearing of vegetation
typesproducti ve as wi ldli fe habi tat components.
(6)Minimizing volume requirements for borrow extrac-
t ion.
E-3-291
3.4 -Miti gati on Pl an
(7)Disposal of spoil within the impoundments or
previously excavated areas.
(8)Designing transmission corridors to allow selective
cutti ng of trees and to accommodate uncleared low
shrub and tundra vegetation within rights-of-way.
(9)Dismantling nonessential structures as soon as they
are vacated.
(10)Development of a comprehensive site rehabi litation
plan.
(11)Monitoring progress of rehabilitation to identify
locations requiring further attention.
(12)Acquisition of replacement lands for implementation
of habitat enhancement measures.
(13)Planning and development of an environmental
briefings program for all field personnel.
(14)Avoi dance of the Prai ri e Creek,Stephan Lake,Fog
Lakes,and Indian River areas by access routing.
(15)Restriction of public access during construction by
gati ng the access road.
(16)Use of si gns and possi bly regul atory desi gnati ons and
measures to discourage use of ORVs and ATVs.
(17)Phased implementation of the project Recreation Plan
with interagency review and concurrence.
(18)Siting and alignment of all facilities to avoid
wetlands to the maximum extent feasible.
(19)Agency coordi nati on and parti ci pati on in detai led
engineering design and construction planning of civi 1
engineering measures to minimize potential wetlands
impacts.
(20)High-resolution mapping of wetland vegetation within
the project area,in coordination with COE and USFWS
representatives to be conducted in 1983.
Mitigation schedules and costs are presented in Table
E.3.177.A summary of agency consultation is provided in
Section 4.4.4.
E-3-292
"""
-
-
4 -WILDLIFE
4.1 -Introduction
Populations of many wildlife species inhabit the Susitna project study
areas,which for wildlife include the watershed of the Susitna River
upstream from Gold Creek (Figure E3.33),a corridor extending approxi-
mately 1 mile (1.6 km)to each side of the downstream flood plain
between Gold Creek and Cook Inlet (Figure E3.34),transmission corridor
study areas 5 miles (8 km)in width from Healy to Fairbanks and Willow
to Anchorage (Figure E3.35),and the intertie transmission corridor
from Willow to Healy,with a study area varying from approximately 4 to
18 miles (6.5 to 29 km)(Figures E3.35 and £3.37).While the
ecological importance of all species that are members of the Susitna
basin community is recognized,the emphasis of this report is on the
wildlife resources which can be assigned priority based on the irrela-
tive abundance,regional rarity.or their contribution to recreation,
susbistence,or commerce.Species classified as threatened or
endangered are considered particularly important.
The complexity of interactions and relationships between species in any
ecosystem necess i tates a system of pri orit i es in the development of
mitigation plans.Consequently,some species require less intensive
study then others.The content of Section 4.2,the Baseline Descrip-
tion of wildlife resources,reflects this prioritization of species.
It should be recognized that the priorities assigned are an aid in
developing a mitigation plan with compatible components--with recog-
nized tradeoffs in benefits to some species at the expense of others,
but with as little antagonism between incompatible mitigation measures
as possible.
Data on the vertebrate fauna in the Susitna basin were collected in
several independent investigations.The ADF&G and University of Alaska
reports (listed below)provided most of the data and analysis presented
in this document.Raw data and quantification to support interpreta-
tions are presented whenever these source documents have provided such
numbers.In many instances,such quantification has not been provided
and this discussion then relies on the interpretation of the investi-
gators.In such cases,a reference to the source document is given to
allow the reader access to the same information in its original form.
Data sources are as follows:moose·ADF&G (1982a and 1982b);caribou
-ADF&G (1982c);Dall sheep -ADF&G (1982d);brown bear and black bear
-ADF&G (1982e);wolf -ADF&G (1982f);wolverine -ADF&G (1982g);fur-
bearers -Gipson et a1.(1982);and birds and small mammals -Kessel et
al.(1982a and 1982b).The most recent information from these continu-
ing investigations was provided by personal communications and unpub-
lished tables to allow the most up-to-date analysis for this report.
4.1.1 -The Vertebrate Fauna
Birds and mammals are the wildlife groups of interest in this
study.Kessel et al.(1982a,1982b)encountered 135 species of
birds in the Susitna Basin upstream from Gold Creek (Appendix
3E);82 species were found along the Susitna River floodplain
E-3-294
,...,.
i
-
-
4.1 -Introduction
downstream from Devil Canyon in June 1982 (Appendix 3F).Sixteen
species of small mammals--shrews,rodents,and hares are known to
occur in the middle Susitna Basin (Kessel et ale 1982a).The
middle basin is that area extending outward to the watershed
boundary from the Susitna River between its confl uences with the
Tyone River and the Chulitna and Talkectna Rivers (Figure E.3.3).
Moose,caribou,Dall sheep,.brown bear,black bear,wolf,and
wol veri ne are bi g game speci es that occur in the project area.
Furbearers include beaver,muskrat,river otter,mink,pine mar-
ten,red fox,lynx,coyote,and short-tailed and least weasel
(Gipson et ale 1982).Scientific·names of bird and mammal
species are listed in Appendices 3.E,3.F,and 3.G.
4.1.2 -Threatened or Endangered Species
No threatened or endangered species of wildlife has been encoun~
tered recently in the Susitna project area.White (1974)obser-
ved two peregrine falcons in 1974 along the Susitna River in the
Devil Canyon impoundment area,and one inactive nest near the
northern transmission line.Kessel et ale (l982a)observed no
peregrine falcons or other threatened or endangered species dur-
ing their 1981 and 1982 studies.The potential presence of
peregrine falcons is discussed in greater detail in Section 4.2.3
(a).With the exception of the peregrine falcon,none of the
species known to occur in the project area is rare,threatened,
or endangered in the state of Alaska.
4.1.3 -Species Contributing to Recreation,
Subsistence and Commerce
All big game species of the project area contribute to recrea-
tion,and the yearly big game harvest contributes to local and
regional subsistence (Exhibit E,Chapter 5).Furbearers contri-
bute to the commerce of fur trappers in the Susitna regi on.Few
birds are hunted in the project area.In theory,birds contri-
bute to nonconsumptive forms of recreation such as bird-watching,
but the area is too remote to attract many peopl e who come sol ely
to see birds..
Moose,caribou,black bear,-and brown bear are the most abundant
big game species in the project area and are given highest prio-
rity.Dall sheep,wolf,and wolverine are regionally less abun-
dant and are assi gned secondary importance.Furbearers are con-
sidered less important than big game species.Beaver,marten,
and muskrat are common enough to be readily available to trappers
but have limited economic importance.Otter,mink,red fox,
coyote,lynx,and weasel are given low priority.
E-3-295
4.2 -Baseline Description
Bird and small mammal species contribute little to consumptive
use in the Susitna basin.Certain bird species,such as bald and
gol den eagl es (whi ch have received national protecti on),trump-
eter swans and other waterfowl,can be identified as high profile
speci es and assigned priority on that basi s.Other bi rds and
small mammals have historically contributed little to recreation,
subsistence,or commerce in the project area.In addition,each
group includes a large number of regionally abundant species of
whi ch few can be assigned pri ority over others.These factors
preclude a detailed analysis of the biology and anticipated
impacts to individual species of small mammals and birds of the
middle and lower Susitna basin.However,behavioral characteris-
tics of these small-bodied animals,such as small movements and
home range and use of mi cro-habitats,serve to justify thei r
treatment in groups of organisms with superficially similar
requirements that will be affected in similar ways.These biases
in treatment relative to the higher priority species are allevia-
ted somewhat by the fact that mit i gat ion servi ng to preserve
habitat for larger species will also serve to protect an assem-
blage of the small birds and mammals essential to the maintenance
of a functioning wildlife community.
4.2 -Baseline Description
4.2.1 -Big Game
(a)Moose
Studies of moose in the Susitna Basin have been conducted by
the Alaska Department of Fish and Game in two discrete
areas:(l)the middle and upper Susitna Basin,including
all parts of the watershed upstream from the Devil Canyon
damsite,and (2)the lower Susitna Basin,including the
major valley and floodplain of the Susitna River from Devil
Canyon downstream to the river mouth at Cook Inlet.The
river basin below Devil Canyon can be divided into 3 sec-
tions based on river morphology.Between Devil Canyon and
Talkeetna the river is then characterized by rapid flow in a
single channel less than 500 feet (150m)wide,with widely
separated islands covered with mature forest.The banks are
steep and covered with alder shrub and spruce-birch forests.
Between Tal keetna and Montana Creek the ri ver wi dens 1.2
miles (2 km)and becomes braided with many small islands in
a broad floodplain.Below Montana Creek the river is gener-
ally very broad,between 3 and 12 miles (5-19 km),with up
to 15 channels and numerous sloughs and oxbow lakes.Dis-
turbed habitats are much more abundant because of along
hi story of settl ement and other development effects.Adja-
cent shores and large islands are heavily forested.
E-3-296
....
--
....
-
4.2 -Baseline Description
Studies in the middle and lower Susitna basins have add-
ressed different aspects of moose ecology.The differences
in approach prima rily refl ect the differences in topography
and vegetation in each portion of the basin,as well as dif-
ferences in the development scenarios and potential impacts
in the two areas.Consequently,comparabl e information on
moose in all areas of the Susitna Basin is not always avail-
able.The following discussion of moose ecology in the
Susitna basin provides a summary of the current state of
knowledge for moose in the middle and lower portions of the
basi n.Simil arit i es and differences in vari ous aspects of
moose ecology that may be influenced by the Watana and Devil
Canyon projects will also be discussed.
Most of the information contained in the following discus-
sion is based on studies by ADF&G (1982a,b)in the middle
and lower Susitna b~~ins.Additional studies and communica-
tions are cited as necessary.
(i)Distribution
Moose occur throughout the Susitna River drainage-
and,because of their regional contribution to sub-
sistence,are one of the most economically important
wildlife species in the region (see Chapter 5).
Within the Susitna Basin,moose tend to be most abun-
dant in the upstream area east of and including
Tsusena and Kosina Creeks and within the main Susitna
vall ey downstream from Montana Creek to the river
mouth at Cook Inlet.Low numbers of moose presently
inhabit the area between Devil Canyon and Talkeetna.
-Seasonal Movements
Moose in many northern areas undergo regul ar sea-
sonal movements or migrations (see LeResche 1974
and Coady 1982 for a review).LeResche (1974)des-
cribed moose migrations as regular annual movements
that i nvol ve return to at 1 ea st one common area
each year.In some areas such as the Arctic
Coastal Plain of Alaska (Mould 1979)or northern
Minnesota (Van Ballenberghe and Peek 1971),migra-
tory movements may invol ve di stances of only
1.2-6.2 miles (2-10 km)with little change in ele-
vation.Migrations in mountainous areas usually
involve large changes in elevation.Horizontal
differences between summer and winter ranges may be
as little as 1.2 miles (2 krn)(Knowlton 1960)or as
great as 105 miles (170 km)(Barry 1961).In in-
terior Alaska,moose spend the summer at low eleva-
tions,move to high elevations during fall and
E-3-297
4.2 -Basel ine Description
early winter,and return to 10\Er elevations during
mid-to late-winter (Bishop 1969).Migration of
moo se appear s to be an ad apt at i on to opt im i ze sea-
sonal use of forag e hab itats (Co ady 1982).
Weather conditions,particularly snow depth and
structure,are among the most important factors
associated with moose migration (Coady 1974,
LeResche 1974).Winter severity may influence the
distance moved by individuals as well as the pro-
portions of moose in a popul ation that migrate to
different areas.For excmple,during a winter of
1 ight snow in south-central Al aska,some groups of
moose overwintered on summer ranges ....nile other
groups migrated to adjacent winter range (Van
Ballenberghe 1978).During winters of deep snow,
hO\Ever,almost all of the moose migrated from the
summer ranges to low elevation winter ranges.
In the middle Susitna Basin,some groups of moose
exhibit seasonal shifts in distribution.Other
groups undergo very 1 imited seasonal movenents and
remain in low elevation riparian and forest commu-
nities year-round.ADF&G (1982a)del ineated 13
subpopul ations of moose in the middle Susitna Basin
on the basis of seasonal movenent patterns.
Over 2700 rad io 1oc at ions obtained from 207 moo se
during the period from October 1976 through August
1981 indicated that most moose in the middle
Susitna Basin moved to lower elevations during late
spring and early SlJ11mer;mean elevations of reloca-
t ions for Apr il and May were 2575 feet (785 m)and
2641 feet (805 m),respectively (ADF&G 1982a).As
SlJllmer progressed,moose moved to higher elevation:;
and commonly remained there throughout the winter
period.The highest mean elevation of 2956 feet
(901 m)occurred in December.
These seasonal trends in el ev ation are quite d if-
ferent from seasonal patterns observed during pre-
vious studies in the middle Susitna and Nelchina
river basins.Van Ballenberghe (1978)and Ball ard
and Taylor (1980)both observed that moose tended
to occupy areas at 2500-2999 feet (762-914 m)ele-
vation during the SlJllmer and moved to el ev ations of
1798-2202 feet (548-671 m)during the winter.
ADF&G (1982a)attributed the use of higher eleva-
tions by moose during 1980 and 1981 to mild
E-3-298
-
.....
.....
4.2 -Basel ine Description
wi nters,and suggested that hi gh wi nd s and tempera-
ture inv ersi ons resulted in red oced snow depths at
hi g her el ev ati ons.Browse was consequentl y more
accessible in these areas than at 10\\er eleva-
tions.
Use of regional areas within the middle Susitna
Basin by moose al so appears to be infl uenced by
slope steepness.Slopes were classified into four
broad categories:flat--O to 10°,gentle--ll to
30°,moderate--31 to 60°,and steep--61 to 90°.
During both summer (May to August)and winter
(Novenber to April),91 percent of moose reloca-
tions occurred on flat and gentle slopes (ADF&G
1982a).The aspect of the slope,hO\\ever,did not
appear to infl uence moose locations.
Detailed information on the distribution of moose
in the 10\\er Sus itna Bas in is 1 im ited to the c ur-
rent stud ies being sponsored by the Power Author-
ity (A[J'&G 1982b).Jll1 unspecified total nUTIber of
relocations for 3 males and 3 females between
mid-April 1980 to mid-March 1981,and 7 mal es and
25 femal es between mid-March and October 1981 are
presented by ADF&G (1982b).
In general,riparian habitats are at least season-
all y important to moose in all reac hes of the 10\\er
Susitna River.Winter ranges for moose throughout
the lower Susitna Basin are located in riparian
areas.Ri pari an commun it i es are al so commonl y used
as calving areas by moose north of Tal keetna,as
year-round habitat for moose in the Delta Island
area,and as transition range for moose south of
Ta 1 keetna (ADF&G 1982b).(Moose in the area so uth
of Tal keetna appear to util ize seasonal ranges on
both sides of the river valley.)
-Spec i al Us,e Areas
.Calving Areas
Parturition generally occurred bet\\een May 15 and
June 15 in the year:s 1977 to 1980.To determine
whether cal v ing concentrati ons occ urred in or
adjacent to the proJX)sed impoundment areas,all
observations of radio-collared cow moose (n=37 in
1980;n=53 in 1981)in the middle Susitna Basin
E-3-299
4.2 -Baseline Description
were plotted (see Figure E.3.86)(ADF&G 1982a).
A1though thi s method i ncl udes some cows whi ch
were not obs erved wi th calves,it does p rovi de
locations of areas where cows probably cal vee
(This error is 1 ikely small because calf mortal-
ity immediately following birth is high [Ballard
and Taylor 1980,Ballard et ale 1981a]and many
parturient cows would consequently not be
observed with calves.)
Cow moose were distributed throughout the middle
Susitna Basin,but several concentrations of
radio-collared cow moose were observed (ADF&G
1982a).These included:Coal Creek and its tri-
butaries;the Susitna River from the mouth of the
Tyone River downstream to a point several mil es
downstream from Clarence Lake Creek;Jay Creek to
Watana Creek;the area in the vi ci nity of the
mouths of Deadman and Tsusena creeks;Fog Creek
to Stephan Lake;and opposite Fog Creek to Devil
Creek.Low shrub and open spruce habitats were
the most common cover types in the vi ci nity of
these concentrations.The importance of these
sites as traditional calving areas is not known.
Calving ranges for 36 moose were obtained in the
lower Susitna Basin (ADF&G 1982b).Within the
lower Susitna Basin,calving concentrations up-
stream from Talkeetna occurred in cover types
different from those used downstream from
Talkeetna.Six of 10 females and neither of two
males north of Talkeetna were in riparian habitat
during calving.Only 4 of 21 moose south of
Talkeetna were in riparian habitats during calv-
ing.Radio-collared females upstream from
Talkeetna generally moved to riparian or island
habitats during the calving period (ADF&G 1982b).
Cottonwood was the predominant cover type in the
vi ci nity of most rel ocati ons duri ng the cal vi ng
period.
In contrast,radio-collared cow moose in the
Susitna Vall ey south of Talkeetna generally 1eft
the overwintering riparian areas by late April
and did not return to these areas until well
after the calving period (ADF&G 1982b).A pos-
sible calving concentration was observed in the
vicinity of Trapper Lake,but most cow moose were
wi dely di spersed at va ryi ng di stances from the
E-3-300
~,
-
-
4.2 -Baseline Description
Susitna River (ADF&G 1982b).On average,cow
moose were 1ocated9.1 mil es (14.7 km)from the
river during the calving period.However,sev-
eral females calved on the river islands and
remained there throughout the'year.Cow moose in
the area south of Talkeetna were generally ob-
served in cover types more typi ca 1 of calvi ng
habitat in other areas of Alaska (e.g.,Rausch
1958;Bailey and Bangs 1980);a mosaic of spruce
and al der interspersed wi th muskeg bog meadows
was the most common cover type near relocations
(ADF&G 1982b)..
A common feature of calving habitats in the lower
Susitna Basin is their close proximity to water
(ADF&G 1982b).Although the presence of water
may be an important attribute of calving sites,
it is more ..1 ikely that cow moose seek these areas
because of the availability of newly growing
herbaceous vegetation (LeResche and Davis 1973,
ADF&G 1982b).Such vegetation would provide
lactating cows and newborn calves with a readily
available source of easily digestible,highly
nutritious forage (Weeks and Ki rkpatrick 1976,
Fraser et al.1980)•
•Breeding Areas
Breeding concentrations in the middle-Susitna
Basin were determined by plotting the locations
of all radio-collared cow moose (n=37 in 1980)
between September 20 and October 20 du ri ng 1977
to 1980 (see Figure E.3.87)(ADF&G 1982a).Most
cow moose occupi ed upl and sites away from the
proposed impoundment areas (ADF&G 1982a).
Concentrations occurred in the following areas:
Coal Creek to the big bend in the Susitna River;
Cl arence Lake;upl ands between Watana and Jay
Creeks;Stephan Lake to Fog Lake;and the uplands
above the mouth of Tsusena Creek.Other
concentrati on areas away from the proposed
impoundments include northwestern Alphabet Hills,
the Maclaren River,and the area upstream from
the mouth of Valdez Creek (ADF&G 1982a).
In the lower Susitna Basin,few moose were obser-
ved in riparian habitats during the breeding
period (ADF&G 1982b).With the exception of
moose that remained in riparian communities or on
E-3-301
4.2 -Baseline Description
the river islands throughout the year,most moose
were located farther from the Susitna River dur-
ing the rut than during the calving period (ADF&G
1982b).Average distances from the ri ver were
9.6 miles (15.5 km)and 15.4 miles (24.8 km)for
cow and bull moose,respectively.Use of spe-
cific cover types during the breeding period was
not assessed.
-River Crossings
Between October 1976 and December 1981,33 radi 0-
collared moose made a minimum of 73 crossings of
the middle Susitna River.Of 40 river crossings by
radio-collared animals during 1980-1981,all occur-
red during the months of May through November.
Distributions of the crossings were:May -20 per-
cent,June -7.5 percent,July -12.5 percent,
August -12.5 percent,September -25 percent,
October -12.5 percent,and November -10 percent
(ADF&G 1982a).
Track surveys on March 24,1981,provided observa-
tions)f an additional 73 crossings of the Susitna
River by moose.Based both on crossings by radio-
collared animals and on track sightings,records of
crossings of the Susitna River occurred throughout
the proposed impoundment areas.However,crossings
tended to be concentrated in several major areas
along the Susitna River;these included from Goose
Creek to Clearwater Creek.Jay to Watana Creeks,
from the mouth of Deadman Creek upstream for
approximately 5 mi 1es (8 km),and the mouth of Fog
Creek downstream to an area near Stephan Lake
(ADF&G 1982a).
Information on movements of radio-collared moose in
the middle Susitna Basin between October 1976 and
mid-August 1981 suggests that some of the above
crossing concentrations may be associated with
migratory movements.In general,movement patterns
of most moose approximated the drainage patterns of
creeks and tributaries of the mainstem rivers
(Figure E.3.88).Consequently,most movements in
the mi ddl e Sus;tna Basi n i nvol ved a north-south
movement pattern.Cross i ng sites for these
generalized movements that occur within the pro-
posed impoundment areas i ncl ude the lower porti on
of Watana Creek,the Jay-Kosi na creeks area,and
the movement corridor along the Susitna River.No
E-3-302
r-
....
-
~
I
!
-
4.2 -Baseline Description
river crossings by moose have been documented in
the reach between Devi 1 Canyon and Portage Creek.
where steep canyon walls physically prevent cros-
sings.
(ii)Habitat Use
-Cover Requirements
Because moose are largely dependent on woody browse
during winter and late spring.their distributions
are more closely associated with the distribution
of commonly utilized browse species than with other
envi ronmental factors (Coady 1982).However,the
mi nimum requi rements of moose for wi nter food and
cover appear to be satisfied by a great diversity
of habitat types across North America.suggesting
that moose are adaptable to a vari ety of condi-
tions.
Habitat use by moose is most extensive areally dur-
ing the summer and fall and is gradually restricted
during the winter (LeResche et al.1974).Lowland
and upland climax shrub communities are heavily
utilized during summer and fall.By early winter,
moose commonly move to upl and and 1owl and seral
communiti es.During wi nters of deep snow,upl and
seral communities are abandoned in favor of lowland
areas (ADF&G 1982a).
In western North America,shrub communities are the
most important winter habitats for moose (LeResche
et a1.1974).In particular,riparian willow
(Salix spp.)stands provide high quality winter
range.(However.moose highly prefer some species
of willow over others.)Maximum use of these areas
occurs during mid-to late-winter and during severe
wi nters.Areas of coni ferous forests adjacent to
riparian communities provide bedding areas and
cover and so enhance the value of these shrublands
for moose.
Riparian communities are perhaps the most important
shrub habitats for moose (Coady 1982).Because
riparian areas are frequently di sturbed by all uvi al
action.they provide permanent seral habitats.
Important seral shrub habitat is al so created by
fire,clear-cutting.and other disturbances that
remove cl imax vegetation cover (LeResche et a 1.
E-3-303
4.2 -Baseline Description
1974,Davi sand Franzmann 1979).However,because
moose avoid large clear-cut areas (Hamilton and
Drysdale 1975),widescale removal of mature forest
cover can result in a reduction in moose habitat
value,despite the increase in shrub growth.
Following fire in Alaska,the optimum age of browse
growth is less than 50 years and moose utilization
of these areas usually peaks 20-25 years after
burning (LeResche et ale 1974).
Site-specific information on habitat use by moose
in the middle and lower Susitna basins was based on
aerial assessments of the dominant plant species in
the vicinity of each moose relocation (ADF&G 1982a,
1982b).Although this method of evaluating habitat
use provided some information on the apparent pref-
erence for di fferent forest cover types,two pro-
blems were apparent.
The first problem is associated with diurnal dif-
ferences in habitat use by moose.Linkswiler
(1982)showed that habitat use by moose in Denali
National Park was strongly associated with the time
of day.In general,it appeared that moose rested
in forested areas during the day and became active
in more open cover types duri ng the early morni ng
and eveni ng.Observations of habitat use in the
Susitna Basin consequently may not accurately
refl ect the importance of some habitats to moose
for activities such as feeding or nursing,except
during the wi nter when habitat use is not greatly
influenced by time of day.
The second probl em associ ated with the assessment
of moose habitat use during aerial surveys is that
overstory cover types may not accurately refl ect
habitat components,such as browse availability,
that strongly influence use by moose (see Section
4.3.1(a)[iii]).For example,ADF&G (1982a)indi-
cated that the mi ddl e Susitna and Nel chi na River
basins contain approximately 24 species of willow
(Salix spp.);yet moose commonly utilize only a few
species of willow as browse (Wolff 1976).Because
the distributions of willows and other shrubs are
not directly related to forest cover types,assess-
ments of habitat use by moose on the basis of for-
est cover types is probably misleading.Approxi-
mate equivalents for aerially assessed cover types
and Viereck and Dyrness (1980)vegetation types are
shown in Table E.3.87.Complete descriptions of
E-3-304
-
4.2 -Baseline Description
the plant communities associated with each vegeta-
tion type appear in Tables E.3.53 to E.3.69 •
•Habitat Use in the Middle Susitna Basin
In all seasons,spruce cover types were the areas
most frequently used by 207 radio-collared moose
in the middle Susitna Basin during the period
October 1976 to August 1981,with sparse-and
medium-density,medium-height black spruce (see
Table E.3.88)comprising 40.5 percent of the
total observati ons (ADF&G 1982a).Assumi ng that
Linkswiler's (1982)results apply to the Susitna
Basin,spruce habitats likely represent bedding
or resting habitats.The combined areas of \
conifer forest and.shrubland account for only 59
percent of the total area in the mi ddl e Susitna
Basin,but based on the aerial surveys,received
over 90 percent of the year-round use by moose.
Moose use of upl and shrub habi tats corresponded
closely with observed elevational movements of
moose in this part of the Susitna Basin (Table
E.3.88).Moose were rarely observed in upl and
shrub habitats just prior to cal ving in April
when they tended to be at low eleva t ions (ADF &G
1982a).Use of the upland shrub habitat
increased during the summer and peaked in October
when 43 percent of all moose observed were in up-
land shrub habitat (ADF&G 1982a).High propor-
tions of moose observed were in upland shrub
habitat throughout the winter (ADF&G 1982a).As
discussed earlier,the high use of this cover
type during the winter is likely the result of
mild winter conditions and consequently may not
accurately represent moose habitat affinities
during more severe winters.
During calving in May,140 (52 percent)of 271
moose in the middle Susitna Basin were observed
in sparse-to-medi ulll-densi ty,medi um-hei ght spruce
habitats (ADF &G 1982a).These habitats,whi ch
generally occur near the river and its tribu-
taries,may be selected by parturient females
because of the avai 1abi 1 ity of escape cover and
the early green-up of the vegetation (ADF&G
1982a).Habitats such as birch,alder,and dense
spruce cover types were not commonly used during
the calving period (ADF&G 1982a).
E-3-305
Habitat Use in the Lower Susitna Basin
Habitat use data in the lower Susitna Basin are
derived from relocations of 10 moose captured and
and radi o-coll ared in April 1980 and 29 moose
captured and collared in March 1981.Winter
relocations are available only for the 10 moose
captured in 1980.Additional data on winter
habitat use in the lower basin are being collect-
ed and will be available in June 1983 (Modafferi
1983,pers.comm.).
Habitat affinities of moose in the lower Susitna
Basin differed among the areas south of and north
of Talkeetna and,in some cases,appeared to be
influenced by both the sex of the animal and the
season (E.3.89,E.3.90 and E.3.91).Because
these results are based on a relatively small
number of relocations for a small number of
moose,differrences in habitat use among male
and female moose and among seasons may not be
significant.
Fi fty-four re1 ocati ons were made of the 2 male
moose collared north of Talkeetna between mid-
March and mid-October 1981.All relocations were
in nonriparian communities and most were domina-
ted by alder.spruce and birch cover.
Eight females collared north of Talkeetna provid-
ed 217 relocations.One hundred and ninety-six
were in nonriparian communities dominated by
alder,birch,and spruce.Seventy-six percent of
the 21 riparian relocations were during the calv-
ing period.Riparian relocation sites were
dominated by balsam poplar,alder,and willow.
Five males radio-collared south of Talkeetna
provided 160 relocations,147 in nonriparian
habitats dominated by alder,birch,and spruce.
The 13 riparian relocations were in sites domina-
ted by alder,birch,spruce,and willow (Table
E.3.90).Nineteen females south of Talkeetna
provided 512 relocations.Four hundred and nine
nonriparian relocations were dominated by alder,
birch,and spruce.One hund red and th ree
riparian relocations were in sites dominated by
alder,spruce,birch,and balsam poplar (Table
E.3.91).
E-3-306
-
4.2 -Baseline Description
-Food Habits
Moose are primarily browsers,feeding predominantly
on deciduous woody browse during winter months and
on emergent and herbaceous plants as well as leaves
and 1eaders of shrubs and trees du ri ng the summer
(see Peek 1974 for a review).Food habits of moose
are strongly influenced by browse availability,and
thus there are some differences in the importance
of various browse species to moose in the middle
and lower portions of the Susitna Basin.
Browse utilization studies using the point-centered
quarter method were conducted at randomly selected
sites in the middle basin in 1982 (McKendrick 1982
unpublished data).Only twigs at least 19 inches
(50 cm)above ground were included,since snow pre-
cluded use of twigs below that height during most
wi nters.The percent utili zat i on of the most com-
mon moose browse species for all stands combined
(n=2712)were as follows:Richardson willow (9.8
percent);grayleaf willow (8.9 percent);
diamondleaf willow (8.3 percent);Sitka alder (5.3
percent);and resin birch (5.0 percent).Resin
birch is the most common browse species in the
middle basin.
A preliminary estimate of the winter carrying capa-
city for moose of the Watana impoundment zone
(including all borrow areas,camps,village,and
damsite)and the Susitna watershed upstream from
Gold Creek was calculated from browse biomass
estimates (n=678)obtained in 1982 (Table E.3.92).
A detailed description of the methods used to
determine the browse biomass and the assumptions
involved in calculating carrying capacity are
included in Appendix EH.The number of moose-days
the area can support is based on a winter food
intake value of 5.0 kg dry weight per day (Gasaway
and Coady 1974),and includes only the twigs of the
primary browse species listed above.Based on the
assumptions,the areas within the impoundment zone
and facilities near the damsite could support a
resi dent popul at i on of 301 moose for 180 wi nter
days.The upper and middle basins together have a
winter carrying capacity ,of 23,037 resident moose.
This estimate will be greatly improved through the
use of simulation modeling of moose energy and
protein needs (see Section 4.3.1(a)[iiiJ).The
summer carryi ng capaci ty of the impoundment zone
and nearby facilities (based on a daily consumption
of 11 kg dry weight)is about 5 times that
calculated for winter.
E-3-307
4.2 -Baseline Decription
Chatelain (1951)examined rumen contents of moose
obtained from kills along the Alaska railway and
from hunter kills in the lower Susitna Valley in
the Talkeetna-Houston area.Willows,paper birch,
balsam poplar,and trembling aspen constituted most
of the winter diet.Shrubs such as alder,wild
rose,and high-bush cranberry were rarely consumed.
A simi 1ar analysi s by Shepherd (1958)also i ndi -
cated that the wi nter di et of moose in the lower
Susitna Valley was composed primarily of willows,
paper birch,and trembling aspen.However,because
both of these studies involved moose from nonripar-
i an habitats at some di stance from the Susitna
River,they probably do not accurately refl ect the
diets of moose overwi nteri ng in ri pari an communi-
ties and on river islands in the Susitna River.In
particular,trembling aspen is not present in
riparian communities and so would be unavailable to
moose as a winter forage.
Browse availability and utilization measurements
were obtained from a number of riparian sampl e
sites along the Susitna River during 1980 (ADF&G
1981).Five browse species were considered:
willows,balsam poplar,paper birch,highbush cran-
berry,and wild rose.A mean of 0.13 browse
pl ants/ft 2 (1.4/m2 )was recorded for all
habitat types in the Susitna River valley between
Portage Creek and the Delta Islands.Browse
species were most utilized in equisetum/willow and
medium-tall poplar/willow/alder habitats and least
utilized in medium-dense climax poplar/spruce and
sparse climax birch/spruce.
Percent utilization of willow and poplar was great-
est in habitats where they occurred less frequent-
ly (ADF&G 1981).Birch was seldom found on flood-
plain habitats,but where it occurred near the
river,it was well utilized (26.9 percent).High-
bush cranberry and rose were found mostly in tall
or cl imax habitats but were 1ess abundant than
willows.Utilization of highbush cranberry and
rose was also less than that of willows.
General observations indicated that alder was sel-
dom browsed by moose but in some localities a small
alder clump would be heavily browsed (ADF&G 1981).
Some islands with high quality browse were not used
by moose every winter;moose sign on some islands
i ndi cated heavy use in the past but no use during
the winter of 1979-1980.
E-3-308
r:-""
-
-
!"'"
4.2 -Baseline Description
-Home Ranges
Moose population studies in both the middle and
lower Susitna basi ns i nvol ved bi otel emetry assess-
ment of local and seasonal movements and home
ranges (ADF&G 1982a,1982b).A considerable volume
of information on home range locations,sizes,and
distance relationships to the proposed impoundments
or river channel was obtained.The following dis-
cussi on of home ranges wi 11 concent rate on the
numbers of home ranges that may be potentially
affected by the impoundments in the middle Susitna
Basin and by modification of riparian communities
in the lower Susitna Basin •
•Middle Susitna Basin
To determine the number of moose that seasonally
and annually occupy areas wi thi n or immedi ately
adjacent to the impoundment areas,ADF&G (1982a)
delineated a 28.7-km (17.8 mile)zone around the
impoundment area.The width of the zone was the
average length of the annual home ranges of 162
radio-collared moose in the middle Susitna Basin
for which four or more observations had been made
during 1980-1981.Based on total home range
polygons for 168 radio-collared moose~ADF&G
(1982a)found that 19 had home ranges that fell
outside the 28.7-km (17.8 mile)zone.Of the 149
moose with home range polygons either partially
or entirely within this zone,79 moose had home
range polygons whi ch were either partly or
entirely contained within an area that encom-
passed the proposed impoundments and an
arbitrarily selected 5-mile (8-km)wide zone
adjacent to the impoundment (8 km is approximate-
ly 1/3 of the average home range 1ength).Based
on an estimate of 4500 moose for the middle
Susitna Basin,ADF&G (1982a)calculated that up
to 2402 moose may have home ranges that complete-
ly or partly overl ap the proposed impoundment
a rea and the area withi n 5-mil es (8-km)of the
impoundment.A number of problems concerni ng
equal catchability of animals,sampling inten-
sity,and emigration/immigration of animals
probably invalidate the results of the above
analysis (ADF&G 1982a).However,it does
provi de an approxi mati on of the number of moose
that coul d conceivably be affected by the
proposed impoundments and facilities.
E-3-309
4.2 -Baseline Description
•lower Susitna Basin
All moose for which home range data is available
in the lower basin were captured on or
immediately adjacent to the Susitna River on
April 17,1980 or March 10-12,1981.Riparian
habitats of the lower basin are assumed to be
winter range used in at least some years by all
of these individuals.Most individuals of both
sexes leave the riparian areas by mid-April
(Table E.3.93),the males leaving 2-3 weeks
earlier than females.ADF&G (1982b)divided the
radio-collared sample into 3 loosely defined
subpopulations,based on capture and relocation
data (Table E.3.94).All of these groups were
found at greatest distances from the Susitna
River in the summer (July 1 to August 31)and/or
breeding (September 14 to October 31)periods.
Downstream westside moose (moose radio-collared
downstream from Talkeetna and spending the
breeding season on the west side of the Susitna
River)were found farther from the river than
other groups;4 miles (10.74 km)average for 13
females in the breeding period,and 12 miles
(31.5 km)average for 2 males in the summer
period.
Moose collared in the area upstream from
Talkeetna and on the west side of the river were
commonly relocated either within the river down-
stream from Talkeetna (i.e.,river islands)or
within 1 mile (1.6 km)of the river (most of this
area would presumably be riparian communities)
(Table E.3.95)(ADF&G 1982b).In contrast,moose
on the east side of the river downstream from
Talkeetna did not commonly frequent the river or
riparian areas (ADF&G 1982b).However,because
of small samples,the above use patterns should
be considered preliminary.Biotelemetry studies
of moose in these riparian communities are
continuing so that the number of moose
potentially influenced by these changes can be
better assessed.These data will be available in
June 1983.
(iii)Population Characteristics
-Historical Population Trends
Although moose population studies specific to much
of the middle Susitna Basin were not initiated
E-3-310
....
....
-i
4.2 -Baseline Description
until the late 1970s,the Alaska Department of Fish
and Game has been conducting annual aerial censuses
in Game Management Unit (GMU)13 since 1955 (ADF&G
1982a).Portions of GMU 13,specifically Count
Area (CA)6,CA 7 and CA 14,occur partly or en-
tirely within the middle Susitna Basin
(Figure E.3.89);survey data for those areas are
presented in Tables E.3.96 through E.3.98.
Historical descriptions of moose populations within
GMU 13 are provided by Rausch (1969),Bishop and
Rausch (1974),McIlroy (1974),and Ballard and
Taylor (1980).The following discussion is based
on ADF&G (1982a).
Duri ng the 1950s,moose popul at ions in GMU 13 i n-
creased rapidly and reached high densities about
1960.After the severe winter of 1961-1962,the
population declined and continued to decline with
severe winters occurring in 1965-66,1970-71,1971-
72,and 1978-79.Fall cow-calf ratios,as well as
several other indices of population productivity,
declined sharply and reached a record low for the
basin in 1975.Sex and age composition data for
CA 7 and CA 14 have basically exhi bited the same
patterns described for the unit.Since 1975,the
moose population appears to have increased slightly
or remained stable,even though calf survival has
remained relatively low.
-Population Estimates -Middle Susitna Basin
In order to obtain accurate estimates of moose pop-
ulation sizes in portions of the middle Susitna
Basi n,ADF&G (1982a)i ntensi vely surveyed CA 7 and
CA 14 during November 5-8,1980.Moose populations
in all portions of the middle basin were not sur-
veyed because of unfavorabl e snow conditions and
the high costs of intensively surveying such a
large area.During the aerial surveys of CA 7 and
CA 14,a total of 743 moose were observed within 26
sample areas comprising 234,240 acres (948 km 2 ),
or an equi va 1ent of 39 percent of the two count
a rea s comb i ned.
A moose census is conducted by fi rst strati fyi ng,
or partitioning,the census area into subunits
(strata)having similar moose densities.Moose
densities within strata designations are relative
values within a particular census area only.The
E-3-311
4.2 -Baseline Description
evaluation of moose densities during a stratifica-
tion flight is based on the number of moose
sighted,the density of moose tracks,vegetation
type and elevation,and prior knowledge of the
area.Each strata contains numerous sample units
(SU),which are areas of 8-20 mi 2 (21-52 km 2)
al i gned around topographi c features.A subset of
SUs from each strata are randomly sel ected to be
intensively surveyed,and the results are then
extrapolated to the entire census area based on the
density estimate for each strata.
Table E.3.99 summarizes the calculations utilized
to estimate the fall moose population in CAs 7 and
14 east of Jay and Kosi na Creeks duri ng the early
wi nter of 1980.Of the 604,800 acres (2447 km 2)
census area,35 percent was classified as low moose
density,38 percent as medium moose density,and 27
percent as high moose density.Based upon census
data,each st rat i fi cat i on wa s est i mated to conta in
the following number of moose/acre:low -0.0045,
medium -0.0075,and high -0.0151 (1.12,1.85,and
3.73 moose/km 2 ,respectively).The estimated
total fall population for CAs 7 and 14 was 1986 +
371 (90 percent confidence interval)(ADF&G 1982a)~
Because all moose would not be observed at a survey
intensity of 0.007 min/acre (1.7 minutes/km 2),
porti ons of 10 sampl e areas were randomly chosen
and were resurveyed at a sampling intensity of
approximately 0.019 min/acre (4.6 minutes/km 2)
in an effort to generate a sightability correction
factor.Based on comparisons of total moose counts
during both sets of surveys,it was estimated that
98 percent of the moos e we re obs erved du ri ng the
first surveys,yielding a correction factor of
1.03.The corrected popul at ion estimate for CA 7
and CA 14 was 2046 +382 (90 percent CI),of which
22 percent were calves (ADF&G 1982a).
ADF&G (1982a)were unable to intensively census the
portion of the middle Susitna study area west of
Del usi on and Kosi na Creeks because of unfavorabl e
snow conditions,but an estimate of moose numbers
in this area was obtained during a short survey on
November 29,1980.Stratification of the survey
area indicated that of the 531,200 acres (2150
km 2 )considered,359,680 acres (1456 km 2)were
E-3-312
4.2 -Baseline Description
classified as low densitYt 156 t 160 acres (663
km 2 )as medium density,and 7t 680 acres (7 t 680
acres)as high-density moose areas.Based on this
stratification t a crude population estimate of 1151
moose was obtained.
Similar calculations to those described above were
used to estimate the number of moose in CA 6 (ADF&G
1982a).Population estimates for this area were
derived separately because a migratory group of
moose is known to overwinter near the mouth of the
Oshetna River.During the survey on November 9 t
1980,a total of 205 moose were observed.Of the
300,800 acres (1217 km 2 )stratified,130,560
acres (528 km 2 )were classified as low-moose
dens i ty;..132,480 acres (536 km 2 )as medi um-moose
density;and 37,760 acres (153 km 2 ).as high-moose
density areas.If it is assumed that the moose
stratum densities in CAs 7 and 14 are equivalent to
those in CA 6,a rough estimate of 830 animals is
obtained.The estimated number of moose in the
middle Susitna Basin study area,excluding the far
southeastern portion of the drainage,was 4027 dur-
ing November 1980.
Because of cost constraints and unfavorable snow
conditions,no population estimates were obtained
for a number of areas in the upper Susitna Basi n
(the western Alphabet Hills,the Lake Louise flats,
and the Tyone and Sanona Creek drainages)(ADF&G
1982a)•
-Population Estimates -Lower Susitna Basin
Estimates of moose density in the lower Susitna
Basin (Table E.3.100)are based on ten aerial
surveys conducted in ri parian communiti es withi n
four zones along the lower Susitna River (Figure
E.3.90)(ADF&G 1982b,and unpublished data).
Surveys were flown duri ng peri ods of snow cover,
since moose are more easily observed at that time,
and greater numbers of moose are using the river.
An average of 267 moose was observed during 6 sur-
veys conducted during the winter of 1981-82 (range
of 82 to 309).These surveys i ndi cate that moose
were generally most abundant along the Susitna
River during early March.Heavy snowfall in
October to December 1982 resulted in much
E-3-313
4.2 -Baseline Description
higher use of the lower river by moose.In early
December 1982,826 moose were observed within the
survey area.During all surveys,moose densities
were consi stently higher downstream from Montana
Creek than between Devil Canyon and Montana Creek.
-Population Structure
•Middle Susitna Basin
Information on the population structure of moose
in a portion of the Susitna Basin (GMU 13)is
available since 1955 (ADF&G 1982a);summaries of
a number of popul ati on rat i os suc has cow:ca 1f
ratios and sex ratios are summarized for CA 6,
CA 7,and CA 14 in Tables E.3.96 to E.3.98.In
all three count areas,the number of males per
100 females has declined substantially since
1955.Declines in the number of calves and twin
calves per 100 females have also been observed.
These data suggest that moose productivity in the
middle Susitna Valley has declined over the past
25 years.Recent decl i nes in producti vity have
been attributed largely to brown bear predation
of young calves (Ballard and Spraker 1979;
Ballard et ale 1980,1981a).ADF&G regulates
moose harvest in 13 by limiting the legal
take to large maTeSl36-in.wide neck).This
further reduces the number of males per 100
females,but is designed to protect the
productive population because of low recruitment
(due to high predation mortality)•
•Lower Susitna Basin
Information on the sex and age composition of
moose in the lower Susitna Basin was obtained
du ri ng the surveys descri bed ea rl i er for popul a-
tion estimates (ADF&G 1982b and unpublished
data).Because composition surveys in the lower
Susitna Basin included only information obtained
during the late fall and winter of each year,
(when males and females are more difficult to
distinguish)only sex and age composition data
from the early surveys in December 1981 and 1982
will be considered (Table E.3.101).Males tended
to be less abundant than females in both years.
Comparisons of the number of calves per 100
females in 1981 for the lower Susitna Basin
(48.4)and the middle Susitna Basin (32.2,based
on estimates from the census surveys)suggest
E-3-314
-
....
..-
4.2 -Baseline Description
that moose populations in the lower Susitna Basin
may be slightly more productive than moose in the
middle basin •
•Mortality Factors
Moose populations in several areas of Alaska,
i ncl udi ng GMU 13 (whi ch i ncl udes part of the
Susitna Basin)have undergone population declines
in recent years (McIlroy 1976).A series of
severe wi nters during the 1970s was bel ieved to
have resulted in these declines,and low annual
recruitment associated primarily with poor calf
survival prior to November has been suggested as
the predominant factor maintaining these
populations at low levels (Ballard et ale 1980)•
Predation'of moose cal ves by wolf and brown bear
is believed to be the most important factor
contributing to low calf survival.Other factors
such as decreasing range quality,low bull:cow
ratios,and periodic severe winters are thought
to be less important influences on calf survival
(McIl roy 1974).
Intensive studies of moose populations in the
Nelchina Basin were undertaken by the Alaska
Department of Fish and Game during the mid-1970s
to determine which factors were most important in
determining calf survival.Studies by,Van
Ballenberghe (1978)and Ballard and Taylor (1978)
suggested that bull :cow ratios were not a major
influence on population productivity.Several
measures of physical condition of moose also sug-
gested that moose in the Nelchina Basin were in
good physical condition and that deteriorating
range conditions were not a problem (Franzmann
and LeResche 1978).Furthermore,artificial
reduct ions in wolf popul at ions resulted in no
large increases in calf survival,suggesting that
a lthough moose were an important component of
wolves'diets,wolf predation on moose was not a
major factor in declining productivity (Ballard
and Spraker 1979).In the course of these inves-
tigations,it became apparent that brown bear
predation of young moose calves was a major
source of calf mortality (Ballard and Taylor
1978,Spraker and Ballard 1979).A recent study
of moose calf mortality in the Nelchina and upper
Susitna River basins (Ballard et al.1980)showed
that of 136 calves radio-collared shortly after
parturition,55 percent died of natural causes by
E-3-315
4.2 -Baseline Description
the fo 11 owi ng November.Brown bear predat i on of
moose calves accounted for 79 percent of the
natural deaths.
Mortality of newborn moose calves in the middle
Susitna Basin·during 1980 and 1981 was high
(ADF&G 1982a).By August 1,1980,23 (77
percent)of the calves were missing.Rates of
1980 calf loss were compared with those observed
in 1977 and 1978 (Figure E3.91).Although causes
of moose calf mortal ity were not determi ned in
1980,the pattern of loss was quite similar to
that observed in GMU 13 during 1977 and 1978
where predati on by brown bear accounted for a
high proportion of the natural calf deaths
(Ballard et ale 1981a).
Calf mortality was not directly monitored during
1981 but indices of calf production suggest that
brown bear predation may again have accounted for
a large proportion of the natural deaths (ADF&G
1982a).Of the 46 sexually mature cow moose
which could have produced calves,only 20 (43.5
percent)were observed with calves;four (20 per-
cent)produced twins.The calving rate for known
producers was 1.2 calves/cow.Of the 24 known
calves,14 (58.3 percent)were missing by July
28.This pattern of calf loss is agai n quite
similar to that of 1977,1978,and 1980 when pre-
dation by bears accounted for most of the
losses.
Although predation by brown bears does appear to
be the major cause of calf moose mortality during
the summer and fall peri ods,wi nter severity is
likely an important factor in determining produc-
tivity and survival.Ballard et ale (1981a)
found that snow depths from the Monahan Fl ats
area were significantly correlated with subse-
quent fall calf:cow ratios in CA 3 of GMU 13.
During the period from 1970 to 1978,45 percent
of the variation in cow:calf ratios could be
attributed to snow depth.Snow may alter the
energy balance of moose by increasing metabolic
requirements for locomotion and decreasing acces-
sible energy reserves by limiting food availabil-
ity (Coady 1974).Assumi ng that snow depths are
an adequate index of winter severity,the strong
relationship between cow:calf ratios and snow
depths suggest that overwinter conditions and
their influence on the condition of pregnant cows
are an important factor in determining calf
E-3-316
.....
.....
.....
-
4.2 -Baseline Description
survival,and hence,population productivity.As
discussed earlier,winters during the two years
of study of moose populations in the middle
Susitna Basi n have been mild.Consequently,it
has not been possible to obtain site-specific
information on the influence of severe winter
conditions on population productivity,habitat
use,or browse utilization.
Ballard and Taylor (1980)examined mortality
rates of adult females based on the loss of
radi o-tagged cows in the mi dd1 e Susitna Basi n
during.1976-1978.During the three-year study,
they estimated that annual adu1 t cow mortal ity
averaged 6 percent.
No instances of predation of calves or adult
moose in the lower Susitna Basin were observed
during 1981 or early 1982.ADF&G (1982b)sug-
gests,however,that most predation which does
occur in the lower Susitna Basin is probably
attributable to brown bears and black bears.
Both species of bear.occur throughout the lower
Susitna Basin;whereas wolves,another major
predator of some moose populations,are rare.
-Dispersal
Limited evidence obtained during the radio-tracking
program suggest that young moose from the mi dd1 e
Susitna basin may disperse into other major drain-
ages in the region (ADF&G 1982a).One male calf
was observed to move 46.5 miles (75 km)from Swim-
ming Bear Lake t.o Coal Lake.Another male calf
moved from near the mouth of Watana Creek to the
upper reaches of Wi ndy and Clearwater Creeks north
of the Denali Highway.
Based on these 2 observations,ADF&G (1982a)
suggests that moose popu1 at ions in other dra i nages
removed from the Susitna drainage may be partly
dependent on the immigration of Susitna moose.
Information on population sizes in the Susitna
Basin during 1980 and 1981 similarly suggest that a
porti on of the increase in numbers of adult moose
may have been the result of immigration from other
areas.During 1980,178 calves and 766 adults were
observed in CA 7.In 1981,a total of 1006 adults
were observed.Even if all of the 1980 calves had
survived (which is unlikely),the increase is 21.1
percent greater than expected.Although samp1 ing
E-3-317
4.2 -Baseline Description
errors might account for a major portion of this
difference,immigration from adjacent areas may
partly explain this increase in adult moose.
Evi dence from moose studies in areas adjacent to
the lower Susitna Basi n suggest that the lower
Susitna population is ~iscrete from those in
adjacent drainages.Moose-tagging studies in the
Matanuska River valley (Rausch 1971)and in the
Peter-Dutch Hi 11 s (Di dri ckson and Taylor 1978)
found that emigration from these areas to the
Susitna Basin was extremely low to nil.
(b)Caribou
Caribou in the area affected by the proposed Susitna Hydro-
electric Project are members of the Nelchina herd.This
herd,one of 22 herds in Alaska (Davis 1978),is important
to sport and subs i stence hunters because of its si ze and
proximity to population centers in south-central Alaska.
Currently,the Nelchina herd contains about 21,000 animals
(approximately 6 percent of the total statewi de caribou
population of 325,000).
Despite the great interest by hunters in harvesting Nelchina
caribou (6662 applications for 1600 permits in 1981),the
range remains relatively inaccessible.Human development is
largely limited to the peripheries and consists primarily of
the Alaska Railroad,Parks Highway,Denali Highway,Richard-
son Highway,Trans-Alaska Pipeline,and Glenn Highway.
Cari bou studi es for the Susitna project were conducted by
ADF&G (1982c).All data in this section not otherwise cited
were obtai ned from that source.Data from that report are
derived from 659 radio-locations of 41 individuals (an aver-
age of 16.5 locations for each individual,range 7 to 26),
which were collared for varying amounts of time between
April 1980 and September 1981.Thirty-two were caribou from
the main Nelchina herd,3 from the upper Talkeetna River,3
from the Chunil na Hill s,and 3 from the upper Susitna -
Nenana area.
(i)Distribution and Movement Patterns
The Nel chi na herd occupi es an area of approximately
12,800,000 acres (51,800 km 2 )bounded by 4 mountain
ranges:the Alaska Range to the north,the Wrangell
Mountains on the east,the Chugach Mountains to the
south,and the Talkeetna Mountains to the west
(Figure E.3.92).The Nelchina range contains a
variety of habitats,from spruce-covered lowlands to
steep,barren mountains.
E-3-318
-
.....
4.2 -Baseline Description
The Nelchina herd has been studied by the U.S.Fish
and Wi 1dl ife Servi ce and the Alaska Department of
Fish and Game since 1948.During this time,it has
remained essentially within the area outlined above;
however,with the exception of the calving area,
seasonal use of particular areas has varied.
Ea rly records i ndi cate that the herd wi ntered
(January to March)in the upper Nenana River area in
the early 1930s and in the Talkeetna Mountains in the
late 1930s (Skoog 1968).From 1950-1955,the herd
wintered from the Little Nelchina River and Glenn
Hi ghway north through the Lake Loui se Fl ats to the
Denali Highway.As the herd increased in size
through the later 1950s and early 1960s,its winter
range also increased in size,encompassing the upper
Nenana River area~Monahan Flats,Tal keetna Moun-
tains,and extending east across the Richardson
Hi ghway (Hemmi ng 1971).The most recent studi es of
radio-collared caribou in 1981 and 1982 indicate that
over 85 percent of the caribou in the herd wintered
(1)on the Lake Louise Flats and the middle portion
of the Gakona and Chistochina River drainages and (2)
in the western foothills of the Alphabet Hills,areas
di stant from the proposed impoundments (K.Pitcher
1982 pers.comm.).
Si nce 1949,the fi rst year for whi ch records are
available,Nelchina caribou have utilized an area of
about 640,000 acres (1609 km 20 in the northern
Talkeetna Mountains for calving (Skoog 1968,Hemming
1971,Bos 1974).Although the precise areas used
have va ri ed,cal vi ng has taken pl ace between Fog
Lakes and the Littl e Nel chi na River between about
3000 and 4500 feet elevation.The only deviations
have been during years with extremely heavy snow
accumulations when some calving took place during the
migration to the traditional calving grounds (Lentfer
1965,Skoog 1968,Bos 1973).In 1980 and 1981,calv-
i ng took pl ace between May 15 and June 10 in the
drainages of Kosina Creek,Goose Creek,Black River,
and Oshetna River (Figure E.3.93)(ADF&G 1982c).
The primary migratory route in 1980 and 1981 from
winter range on the Lake Louise F~ats to the calving
grounds in the eastern Talkeetna Mountains was west-
ward across the fl ats from Crosswi nd Lake and Lake
Lou i se into the Talkeetna Mou nta ins on a front from
Lone Butte to Kosina Creek (ADF&G 1982c).
E-3-319
4.2 -Baseline Description
It appeared that many animals used the frozen Susitna
River between the Oshetna River and Kosina Creek as a
travel route in the spring of 1981 (ADF&G 1982c).In
the spring of 1980 one radio-collared animal,and
presumably also a small portion of the main herd,
moved south and crossed the Susitna River near the
mouth of Deadman Creek.Many animals historically
used this route to the calving grounds after winter-
ing in upper Susitna-Nenana drainages (Skoog 1968).
During spring migration and calving,there is some
segregation of sex and age groups.Although year-
lings and barren cows lag somewhat behind parturient
cows,they also move to the calving area,remaining
scattered along its peri phery (Skoog 1968).Radi 0-
collared Nelchina bulls were found in a wide variety
of locations mostly in transit to summer ranges dur-
ing calving in 1980 ard 1981 (ADF&G 1982c).
Historically,the female-calf segment of the Nelchina
herd has summered primarily in two areas:the eastern
Talkeetna Mountains and across the Susitna River in
the Brushkana,Butte,Deadman,Watana,Jay,and Coal
Creeks complex (Skoog 1968,Hemming 1971).In most
years between 1950 and 1973,varying proportions of
the female-calf segment (ranging from 0-100 percent)
crossed the Susitna River from the calving grounds to
the summer range on the north side of the river.The
female-calf segment of the Nelchina herd spent the
summer period (June 11 through July 31)of both 1980
and 1981 in the northern and eastern slopes of the
Talkeetna Mountains (ADF&G 1982c).Summering radio-
collared males were found in many locations in the
high country of the Nelchina Basin.
In both 1980 and 1981,autumn (August 1 through
September 31)was a time of considerable movement and
dispersal by both cows and bulls {ADF&G 1982c).Com-
pared to the obvious segregation in June and July,it
appeared that considerable mingling of the sexes
occurred.In mid-to-late August 1980,a portion of
the main summeri ng concentrations moved out of the
Talkeetna Mountains onto the western portion of the
Lake Louise Flats,and in some cases,into the
Alphabet Hills.Through September,the distribution
remained relatively stable,with the main herd
divided between the northeastern Talkeetna Mountains,
the Lake Louise Flats,and the Alphabet Hills.
E-3-320
-
4.2 -Baseline Description
data.Pitcher estimated that 2500 caribou were in
the count area,based on an actual count of 2077
caribou and his subjective impressions of sightabi-
lityand area coverage.
Duri ng early May 1980,four adult females and one
adult male were radio-collared from this subherd
(ADF&G 1982c).One of the females migrated to the
main Nelchina calving area,summered in the Talkeetna
Mountains,migrated back through the upper Susitna-
Nenana area in the fall,and rejoined the main
Nelchina herd on the Lake Louise Flats during the rut
and early winter.The other three females remained
in the upper Susitna-Nenana area throughout the study
period,producing two calves in 1980 and two in 1981.
The bull summered in the Cl earwater Mountai ns,then
joined the main Nelchina herd during the rut on the
Lake Louise Flats.
The Chun il na Hill s group appears to be a resi dent
subherd numbering fewer than 340 animals (ADF&G
1982c).One radio-collared bull remained in the
Chunilna Hills from April to November 1980 when it
shed its collar.Two females were collared in the
spring of 1981,both of which subsequently gave birth
to calves in the area.No overlap with radio-
collared animals from the main herd or other sub herds
was noted,although one female did move across the
Talkeetna River.
Small groups of caribou,including cows and calves,
have been seen in most of the side drainages of the
upper Talkeetna River.This appears to be another
resident subherd,probably of fewer than 400 animals,
and having some spatial overlap with the main
Nelchina herd.Three caribou in this upper Talkeetna
River subherd (two adult females and one adult male)
were collared on April 18,1980 (ADF&G 1982c).These
animals were relocated 50 times and were always found
in drainages of the upper Talkeetna River or in the
upper reaches of the nearby Chickaloon River (Figure
E.3.94.One female raised a calf in 1980,and both
raised calves in 1981.The male spent the summer of
1980 in the mountains west of the Talkeetna River.
-I
(i i i)Habitat Use
Habitat use was analyzed from aerial determination of
vegetation cover at each caribou relocation (ADF&G
1982c).
E-3-321
4.2 -Baseline Description
At one time or another during their annual movements,
Nelchina caribou probably use most of the vegetation
types in the Susitna area.However,ADF&G (1982c)
found cari bou mostly in spruce forest,shrub 1and,
herbaceou s vegetati on types,and bare subst rate
types,with virtually no use of mixed or deciduous
forests.
Nelchina caribou show considerable variation in habi-
tat types used seasonally,and types used most by
bull s are di fferent from types used most by cows
(Table E.3.102)(ADF&G 1982c).Bulls tend to use
spruce forests more than cows in all seasons except
autumn,whereas cow use of tundra-herbaceous types is
greater during all seasons than bull use.These
differences are 1 ikely a refl ection of the tendency
of bulls to remain much longer in the forested
wintering areas and to summer at lower elevations
than cows (see Figure E.3.95).Use of shrubland is
similar for cows and bulls overall but differs
seasonally.Bulls tend to use this habitat most in·
summer and autumn,whereas cows use it most duri ng
spring,calving,and summer (ADF&G 1982c).
As mentioned,differences between bull s and cows in
habitat use were partly rel ated to di fferences in
elevation.The sexes occurred at about the same ele-
vations during autumn,the rut,and winter,but
females were consistently found at higher elevations
during spring migration,calving,and summer (Figure
E.3.95)(ADF&G 1982c).
The food habits of caribou vary seasonally with
available plant forage (Skoog 1968).In spring and
summer,grasses,sedges and the buds of willow and
birch are important,and a wide variety of forbs are
eaten as they become available.Except during years
of late snowmelt when new growth is slow to appear,
lichens are unimportant in the spring diet.In late
summer,mushrooms are an actively sought,but minor,
diet item.During autumn,browse becomes less impor-
tant but sedges and grasses remain major diet compo-
nents and lichens assume greater importance.Through
the winter the diet of Nelchina caribou consists of
about equal portions of graminoids and lichens (Skoog
1968)•
(iv)Population Characteristics
The Nelchina herd was estimated to consist of about
E-3-322
1=
-
.....
r-
I
I
1"'"
I
I
4.2 -Baseline Description
40,000 anima 1s when fi rst surveyed in 1955.Subse-
quently,the herd grew to 71,000 in 1962,decreased
to about 7700 in 1973,and currently numbers about
21,000 (Table E.3.103)(ADF&G 1982c).The management
plan for the Ne1china herd (ADF&G 1976)calls for
maintenance of the herd at about 20,000 adult animals
through harvest of the annual increment.
The sex and age composition of the Ne1china herd re-
mained almost the same from fall 1980 to fall 1981.
Cows and bull s 01 der than one year compri sed 49.1
percent and 29.9 percent,respecti ve1y,of the herd
in October 1981.Calves comprised 21.1 percent or
42.9 cal ves per hundred fema 1 es one year and 01 der
(ADF&G 1982c).The proportion of bulls was high com-
pared to the proportion observed in earlier years,a
fi ndi ng that wou1 d be expected ina growi ng popu1 a-
tion that had previously had a low proportion of
males (Bergerud 1980).
Skoog (1968)estimated the overall pregnancy rate of
Ne1china caribou to be 72 percent for females one
year and older from 1957 to 1962.Full reproductive
potential was not realized even in the fully adult
age c1 asses.Only 13 percent of year1 i ng fema1 es
were pregnant compared to 61 percent of two-year-01ds
and 89 percent of fema1 es three years and 01 der.In
1980 and 1981,the proportion of calves in the post-
calving aggregations averaged about 56 calves per 100
females one year and older (ADF&G 1982c).These data
suggest that considerable calf mortality occurs
shortly after bi rth.K.Pitcher (1982 pers.comm.)
estimated that calf survival to 11 months was 43
percent for 1980 cal ves and 60 percent for 1981
calves.Survival rates for older caribou (>1 year)
were 93.5 percent for females and 87 percent for
males.
Survival rates of caribou are influenced by many fac-
tors including disease,'parasitism,weather,acci-·
dents,food availability,predation,and hunting.
Parasit ism and di sease may kill a few cari bou each
year in the Ne1china herd,but these are not major
mortality factors.Wet,cold weath.er during calving
can result in high levels of calf mortality which
Skoog (1968)bel i eved cou1 d ultimately control cari.-
bou population levels.However,this is a factor
that is more likely to affect coastal herds and more
northerly herds than the Ne1china herd (Skoog 1968).
E-3-323
4.2 -Baseline Description
The major factors that are believed to control
caribou mortality and,ultimately,population levels,
both in Alaska and elsewhere,are food availability
and predation (including hunting).In mainland North
America,the population density of most caribou herds
appears to be much below range-carrying capacity and,
indeed,in many herds is much less than the range has
historically supported (e.g.,Parker 1972,LeResche
1975,Bergerud 1980).Food availability in winter,
because of snow cover,is likely to be more critical
than availability in summer,and many early workers
speculated that declines in caribou numbers in North
Ameri ca in the early 1900s were caused by wi nter
forage (mainly lichen)destruction by forest fires
(Scotter 1967).However,evaluations of more rigor-
ous analyses (e.g.,Henshaw 1968,Kelsall and Klein
1979,Klein 1967,Roby 1980,and Bergerud 1974a)show
that starvation or even observabl e debi 1itati on in
caribou during winter is rare except in populations
insulated from predators and prevented from dispers-
ing to unoccupied habitats (Scheffer 1951,Klein
1968,Leader-Williams 1980).
Skoog (1968)bel ieved that neither overgrazing nor
fi re had greatly affected the Nel chi na range in the
early 1960s.The herd was considerably 1arger than
now,and food availability is unlikely to be a major
factor affecting survival in the present herd.
Several authors have presented evidence that caribou
numbers are effectively controlled by predation.For
example,Kelsall (1968),Parker (1972),Miller and
Broughton (1974),and Davis et al.(1980)all report
evidence that caribou numbers have declines as preda-
tor (mainly wolf)numbers increased,or that caribou
numbers have increased as predator numbers decreased.
Bergerud,in two reviews (1974a,1980),demonstrates
convincingly that where capable predators (wolves,
bears,lynx)are common and hunting by man is insig-
nificant,caribou populations are effectively regu-
lated by predation.
Since the introduction of firearms to North America,
hunting has probably been the major cause of popula-
tion declines (Bergerud 1974a,Calef 1980).Calef
(1980)reported that in some herds in the Northwest
Territories,hunter kill is in excess of annual
recruitment.Doerr (1980)isolated excessive hunting
as the primary cause of population declines in the
Nelchina and Western Arcic herds in Alaska.
E-3-324
--
-
4.2 -Ba~eline Description
Hu nt i n9 and wolf predat i on probably accou nt for about
equal portions of the annual mortal ityof the present
Nelchina herd (ADF&G 1982c).Table E.3.104 shows the
1 evel of hu nter harvest from 1972 to 1981.Du ri ng
that time,hunter harvest in years for which herd
size data are available has varied from 1.4 percent
to 9.6 percent of the herd.Hunter harvest was about
4 percent in 1981.
Wolf predation has reportedly varied with the size of
the wolf population (ADF&G 1982c).Skoog (1968)
estimated that wolves took 1.1 -2.6 percent of the
herd from 1957 -1962.More recently ADF&G (1982f)
estimated wolf predation rates varying from 7 -10
percent ,of the herd in 1973 to 2 - 3 percent in 1981.
There appears to be no clear relationship between
wolf and caribou population levels,apparently due to
the high harvest of wolves and,in particular,way
control measures in the early 1950 1 s,appears in
(Figure E.3.96).(Bergerud 1980).
The average natural mortality rate for caribou 1 year
and older of both sexes in 1981 was 8.1 percent.If
ADF&G (1982f)estimate of 2 - 3 percent mortal ity
applies to adults as well as calves (as they sug-
gest),then wolf predation combined with hunter har-
vest (3.9 percent--Tab 1e E.3 .104)accou nt for 50-60
percent of the annual adult mortality in the Nelchina
herd.
(c)Dall Sheep
Da 11 sheep stud i es were condu cted in the mi ddl e Su sitna
River basin during the summer of 1980,spring and summer of
1981,and spri ng of 1982 (ADF&G 1982d,ADF&G u npubl i shed
data).The purpose of these studies was to determine the
locations and seasons when sheep might be affected by proj-
ect activities.The study area includes all drainages flow-
i ng into the Su sitna Ri ver between Kos ina Creek and Gold
Creek and all drai nages west of the Su sitna Ri ver between
the Denal i Hi ghway and Kosi na Creek.Su rvey efforts were
confined to areas of known or suspected Dall sheep habitat
within this area (Figure E.3.97)(ADF&G 1982d).These
areas contain semi-open~precipitous terrain,with rocky
slopes,ridges,and cliffs.
E-3-325
4.2 -Baseline Description
(i)Distribution
There are three general areas in the middle Susitna
Basin that have steep rocky slopes at sufficient ele-
vation to be potential Dall sheep habitat (ADF&G
1982d)•The fi rst of these areas is north of the
Su sitna Ri vel"between the proposed Devi 1 Canyon and
Watana damsites.Aerial surveys were conducted in
thi s area in the Portage Creek and Tsu sena Creek
drainages (Figure E.3.97).The second potential site
for Oall sheep is in the mountains between the
Susitna and Talkeetna Rivers,extending eastward from
the Fog Lakes to Kosi na Creek.The thi rd area is
north of the Su sitna Ri vel"',to the east of Watana
Creek.This area was established as a population
trend cau nt a rea for Oa 11 s hee p by ADF &G i n 1967
(Figure E.3.97).
ADF&G (l982d unpublished data)conducted aerial sur-
veys to determine the seasonal distribution and abun-
dance of Oa11 sheep in the areas described above on
July 22-23,1980;on March 13 and 25,1981;between
May 13 and June 24,1981;on July 28,1981;and on
March 23,1982.The date,location,number,sex,and
age of sheep were recorded for all sightings (ADF&G
1982d).
A total of 72 sheep (7 legal rams,12 lambs,and 54
unidentified)were counted in the Portage Creek and
Tsusena Creek drainages in July 1980.Four sheep
were seen north of Portage Creek,two east of Tsusena
Creek,and the other 66 were seen in the headwaters
regi on of Tsusena Creek.The only previ ou s ADF&G
su rvey in th"i s area was a 1977 cau nt of 91 sheep (8
legal rams,18 lambs,65 others).The 1977 survey
included the Jack River drainage (north of Tsusena
Creek).whi ch was not su rveyed in 1980.All of the
sightings were far from the pro~osed impoundments and
access roads.
During July 1980,only eight sheep (1 ram,7 uniden-
tified)were observed in the Watana Mountain -Grebe
Mou ntai n area.Thi s area is u sed by sheep from a
larger Talkeetna Mountains population.Earlier ob-
servations in 1977 suggested that at least 34 sheep
were present on Mt.Watana.NUmerous observations of
sheep in the Terrace Creek area (a southern tributary
of Kosi na Creek)have been made,but no sheep were
observed du ri ng the 1980 su rvey.
E3 ..326
....,
-
4.2 -Baseline Description
On March 25,1981,a winter distribution survey was
conducted in the same area surveyed in July 1980.
Twenty-two sheep were sighted,and two groups of 3-4
tracks were seen.These data suggest that grou ps of
sheep from the larger Talkeetna Mountains POlXllation
are migrating into the area during winter.All sheep
observations were located on the southern extreme of
the count area,well away from the impoundment.
The Watana Hi 11 s area has been surveyed for Dall
sheep by ADF&G yearly since 1967 (ADF&G 1982d).The
data from the 1980 and 1981 surveys show the same
general patterns as previous surveys (Table E.3.105).
The 1981 count of 209 sheep was the second highest
number of sheep recorded for this a ea.The percen-
tage of lambs was similar to that of past years and
suggests that productivity and survival are remaining
constant.The small number of 1egal rams cou nted
could reflect the rather high (13)sport harvest
taken from this area in 1980 (R.Tobey 1982 pers.
comm.).Although the 1981 count was relatively high,
it is suspected that the population has remained
stable or perhaps increased slightly (ADF&G 1982d).
Sheep in the Watana Hills area were surveyed in March
of 1981 and 1982.Eighty-seven sheep were sighted in
1981 and 77 in 1982,all on south-facing slopes.
Geist (1971a)suggested that south-facing slopes are
an important part of Da 11 sheep wi nter range.They
provide maximum exposure to winter sun and frequently
have shallower snow than slopes with different
aspects.Fewer sheep were observed than in the
summer surveys,probably because of poor observabi-
lity due to snow cover and/or movement of sheep from
the area.
(ii)Mineral Lick Use
Mineral licks are known to be "important for Dall
sheep and are a common component of spring ranges.
Heimer (1973)suggested that they be considered a
critical habitat requirement.The sheep in the
Watana Hi 11 s a rea have been observed frequ ent i ng a
mineral lick along the lower elevations of Jay Creek
at an elevation of about 2200 feet (671 m)•.
Th e Jay Creek mi nera 1 1i ck was overflown from May 6
through June 24,1980;the number,sex,and age of
fhe sheep recorded are shown in Table £.3.18 (ADF&G
E-3-327
4.2-Baseline Deseri ption
1982d).Sheep were sighted on 28 of 33 occasions (85
percent).The largest single group observed was 15,
representing approximately 7 percent of the observed
Watana Hill s summer popul ation,and approximately 17
percent of the observed winter population.
Sheep were observed frequenting other locations adja-
cent to the Jay Creek mineral site (ADF&G 1982d).On
May 23 and 25,1981,groups of 6 and 12 rams,respec-
tively,were observed scraping and eating soil on the
ridge located on the east side of Jay Creek at an
elevation of 2270 feet (692 m),directly opposite the
main lick area (Table E.3.106).Since only rams were
observed on these 2 occasions,the observation could
represent a preferential use of certain areas by sex
or age classes.Also,on 6 days in June,sheep of
different age classes were observed at an area
approximately 2 miles (3.2 km)upstream from the main
mineral area (Table E.3.106).This area also appears
to be mineralized.
No sheep were observed at the Jay Creek drea during
an aerial survey of summer distribution on July 28,
1982.However,ten ewes and yearlings were observed
actively utilizing a known mineral lick in the drain-
age of the east fork of Watana Creek,approximately
7 miles (11.3 km)north of the Jay Creek site.
The Jay Creek mineral lick was also visited by ADF&G
biologists on May 9,1981.Sheep usage of the area
ranged from the Jay Creek streambed 2000 feet (610
m),to the top of the blu ff 2450 feet (747 m),and
for an u ndetermi ned distance away from the b1uff.
Signs of heavy moose utilization were evident as
well.
(d)Brown Bear
Most of the site-specific information for brown bears in the
Susitna Basin was obtained from recent studies by ADF&G
(1982e).Additional site-specific information was obtained
from studies in the upper Susitna and Nelchina River basins
during 1979 (Miller and Ballard 1980,Spraker et ale 1981).
(i)Di stributi on
Brown bears or grizzly bears (the former term will be
used throughout this report)are widely distributed
and abundant in most parts of Al aska.Brown bears
E-3-328
-
""'"
-
4.2 -Baseline Description
appear best adapted to relatively open,undisturbed
areas with good cover and an abundance of perennial
succulent herbs and/or fruit-bearing shrubs (Mealy et
ale 1981).The omnivorous food habits of brown
bears as well as their nongregarious social structure
and high degree of mobility allow them to utilize
resources in a large number of habitats throughout an
expansive area (Knight 1980).Brown bears appear to
be able to adapt to a variety of man-caused
di stu rbances in thei r habitat.However,ex peri ence
has amply demonstrated that brown bear abu ndance is
usually incompatible with human presence;human-bear
interactions commonly have resulted in the
extermi nat i on of brown bea rs from sett 1ed areas
through intensive hunting,trapping,and/or poisoning
programs.
Brown bear research in the middle Susitna and
Nelchina River basins has been ongoing since 1978
(Ballard et ale 1980,Spraker et ale 1981).Most
studies were initially concerned with the effects of
brown bear predation on moose,but more recent
studies have concentrated on all aspects of brown
bear ecology (ADF&G 1982e).No site-specific infor-
mation is available on brown bear in the lower
Susitna Basin.Within the middle Susitna Basin,
brown bears generally are most abundant in open
tundra habitats during most of the late spring and
early fall periods.Many brown bears appear to
utilize lower elevation spruce habitats during the
early spring.Current information suggests that
brown bears in the middle Susitna Basin are abundant
and that populations are young and productive.
-Seasonal Movements
The brown bear's omnivorous feeding habits,social
structure,behavioral interactions,and winter den-
ni ng requ i rements necessitate extensi ve movements
throughout large areas (Craighead and Mitchell
1982).It appears that the utilization patterns of
1 arge geographi c areas by brown bears is 1 argely
dependent on the spati al and temporal avail abil ity
of food.Information from a number of areas in
Canada and the United States suggests that brown
bears establ ish traditional movements to exploit
dependable sources of food.Often these food
sources are only seasonally available for shorf
periods of time.Extensive traditional movements
are common in many populations of brown bear
(Pearson 1976,Reynolds 1979,Craighead 1980).
E-3-329
4.2 -Baseline Description
Based on 530 relocations of radio-collared brown
bears in the middle Susitna Basin during 1980
(n=15)and 1981 (n=18),ADF&G (1982e)documented
regular seasonal movements of brown bears that
appeared to be associated with regional and eleva-
tional differences in food availability.Movements
of brown bears from the middl e Su sitna Basi n to
Pra i ri e Creek du ri ng Ju 1y a nd Au gu st were perha ps
the most notable regional movements observed during
the study.These regu 1ar seasonal movements of
brown bears appeared to be associ ated with hi gh
concentrations of spawning king salmon in Prai'rie
Creek during this time of year.
Although bad flying conditions in 1981 prevented
complete documentation of the number of brown bears
that move the middle Susitna Basin to Prairie
Creek,3 of 11 (27 percent)of the radio-coll ared
bears were found in the Prairie Creek area sometime
between July and December in 1980 (exact dates not
gi ven),and 2 of these same i ndi vidu al s (of 18
collared bears,11 percent)were found there some-
time between July and December 1981 (ADF&G 1982e).
Local residents report that large concentrations of
brown bears occur in the area during king salmon
runs in July and August.Although a large number
of animals may utilize this food source,it is not
cl ear whether brown bears are dependent on the
supply of salmon.For example.moderately dense
brown bear populations exist in the adjacent
Nelchina Basin without access to salmon (Miller and
Ball ard 1982).As suggested by ADF&G (I982e),
Prairie Creek salmon may be an important buffer
when other food sou rces such as berry crops are
less available,and this additional food source
results in a higher carrying capacity of the middle
basin for brown bears.All of the radio-collared
brown bears that moved to the Prairie Creek area
had portions of thei r home ranges north of the
Susitna River,and therefore had to cross the river
en route to or from Prairie Creek.
Movements of brown bear in the early spring also
appeared to be related to el~vation and the avail-
abil ity of new pl ant growth (ADF&G 1982e).With
the exception of sows with cubs,it appeared that
most brown bear moved to lower elevations on or
near the Susitna River following emergence from
overwintering dens.This was attributed to the
relatively earlier melt-off of snow,particularly
on south-facing slopes,and the subsequent
availability of overwintered berries and new plant
E-3-330
-
-
-
-I
,~
4.2 -Baseline Description
growth.Carcasses of wi nter-k ill ed u ngu 1ates and
new-born calves in these areas also would provide
food for brown bears.Radi 0 1ocat ions of brown
bears in the middle Susitna Basin during the
springs of 1980 and 1981 indicated that,excluding
sows with newborn cubs (which rema"ined at higher
elevations),62 percent and 52 percent of the
radio-collared animals,respectively,moved to
areas on or adjacent to the Su sitna Ri ver (ADF&G
1982e).S.Miller (1982 pers.comm.)feels that
these figures are minil11Jm estimates,since spring
use of the impoundment zone by other bears may have
been missed because of infrequent monitoring.
However,since it was impossible to capture a
random sampl e of bears withi n the basi n,these
figures most 1ikely over-estimate use of the area
by the basin-wide popJlation.Females with newborn
cubs remained at high elevations throughout the
year.Brown bears were at the lowest mean eleva-
t ions du ri ng Ju ne to Au gu st (ADF&G 1982e).
Although some of the regional and elevational move-
ments of brown bears in the middle Susitna Basin
may be related to forage availability,these move-
ments may also be associated with brown bear preda-
tion of moose and caribou calves.Directional
movements by four radio-collared brown bears to and
from the calving grounds of the Nelchina caribou
herd suggest that brown bears may move to cal vi ng
areas primarily because of the availability of
calves (ADF&G 1982e).
-Denning
Brown bear dens in the middle Susitna Basin were on
moderately sloping southern exposures,and were
generally dug in gravelly soils either in tussock
or shrub habitats (ADF&G 1982e).(Use of vegeta-
tion types for denning is discussed below.)None
of the bears in this study reused den sites.Brown
bear den sites ranged in elevation from 2330-5151
feet (710-1570'm)with an average elevation of
4180 feet (1274 m).
Radio-collared brown bears in-the middle Susitna
Basi n entered dens in early October 1980 and in
1ate September-early October 1981.!lI ri ng the
spring of 1981,most bears emerged from their dens
in late April-early May (ADF&G 1982e).
E-3-331
4.2 -Baseline Description
(ii)Habitat Use
Brown bears in other areas of Al aska and northern
Canada utilize a wide range of vegetation corruruni-
ties.Habitat affinities of brown bear in the middle
Su sitna Basi n were based on the predomi nant vegeta-
tion types in the vicinity of each relocation of the
radio-collared bears as determined from aerial obser-
vations.Brown bear use of spruce vegetation types,
which are concentrated around and in the proposed
impoundments,was highest in May and June (Table
E.3.107)(ADF&G 1982e).Bears tended to move to
shrublands at higher elevations later in the summer
(58 percent of the observations in September were in
shrubland,whereas only 28 percent of the May sight-
ings were in this type)(ADF&G 1982e).
Comparisons of the use of vegetation types by brown
bears during the spring and the remaining portion of
the year indicated that brown bears used spruce for-
ests significantly more often during the spring than
during other times of the year (ADF&G 1982e).As
di scu ssed earl i er,sows with newborn cubs tended to
remain at higher elevations;of 68 observations of
sows with cubs,only 1 occurred in spruce habitat.
Shrublands were most commonly used by sows with cubs
(49 percent of the observations)followed by "other"
habitats (35 percent),tundra (10 percent),and
riparian communities (4 percent).
-Food Habits
Studies of the feeding habits of brown bears indi-
cate that the species is omnivorous,feeding on a
wide range of plants and animals.Although plant
material may commonly comprise a major portion of
the diet,it appears that brown bears prefer high-
protein animal food (Craighead and Mitchell 1982).
From dietary studies of brown bears in interior
Yu kon (Pearson 1976)and in Yellowstone National
Park (erai ghead and Sumner 1980),it appears that
brown bears most commonly utilize graminoids and
forbs during the spring and early summer.As
berries and fruits become more available,these
also are incorporated into the diet.Brown bears
will eat carrion,if available,and may also kill
ungulates or other large marrunals.Small rodents
such as grou nd squ i rrel s are most often consumed
du ri ng the 1ate summer.
E-3-332
-
-
4.2 -Baseline Description
As discussed earl ier,brown bear are attracted to
both natural and artificial food sources,particu-
larly if food is abu-ndant and read"ily available.
Some brown bear po~l ations traditionally form
aggregations to feed o-n sal mon du ri n9 the major
fi sh ru ns (Stornorov and Stokes 1972).
Information on the di~ts of brown bear in the
middle Susitna Basin is limited.Overwintering
berri es and new green shoots of grasses and forbs
are consumed during the early spring.Winter-
killed ungulates as well as moose and caribou
calves also are eaten.King salmon likely comprise
much of the diet of bears moving to Prairie Creek
during the salmon run in July and August.Berries
such as Vaccinium spp.are 1 ikely consumed thr.ough-
out'the 1 ate summer and fall peri od.
One of the most notable results of the brown bear
studies in the middle Susitna Basin is recognition
of the importance of brown bear predation to moose
recruitment.Ballard et ale (l981a)found that of
123 radio-tagged moose calves,55 percent had died
of natural causes by November (following their
birth)and that 79 percent of all natural mortali-
ties were caused by brown bear predation.Reloca-
tions of 23 radio-collared brown bears that were
intensively monitored (twice per day)during the
s pri ng of 1978,showed that 14 of the 23 bears
reg.ll arly relocated were observed at 1east once on
a moose calf kill (Ballard et ale 1981a,Spraker et
a.l.1981).During the latter study,a total of 37
calf moose,28 adult moose,4 unidentified moose,3
caribou,and 6 other species of mammals were killed
by brown bears,yielding a total of 1 kill/5.6 ob-
servation days (1 moose/6.3 observation days).The
lower kill rate of 1 kill/l0.2 days given by ADF&G
(1982e)is probably an underestimate because of
1 ess frequent monitori ng of radio-coll ared animal s
(compared to Ballard et ale 1981a)and is based on
only 3 moose calves,2 adult moose,and 3 unidenti-
fied prey species.Although the full importance of
this highly preferred food source to brown bear is
not known,Crai ghead and Mitchell (1982)found
spring weight gains only in brown bear able to
secure ungulate calves or similar high protein
diets.
-Home Range
The average home range size of male brown bears in
the middle Susitna Basin is 195,200 (790 km 2 ,
E-3-333
4.2 -Baseline Descr1ption
n==14);for females it is 78~090 acres (316 km 2 ,
n=19)(ADF&G 1982e).
Comparisons of the home range sizes of brown bears
in the middle Susitna Basin with brown bears in
other areas indicate that bears in the Susitna
Basin have relatively large home ranges (Table
E.3.108)(ADF&G 1982e).Only home ranges of bears
from northwestern Alaska (a relatively unproductive
population)were larger.On the basis of this in-
formation,ADF&G (1982e)suggested that home range
size and brown bear densities are inversely related
and that both are a function of the distribution
and abu ndance of food resou rces.The 1 arge home
ranges of brown bears in the Susitna Basin,there-
fore,may reflect relatively low productivity of
food items that are important to brown bears and/or
a patc:',y distribution of important food items.
As di scu ssed previ au sly for moose~home range
analyses are useful in assessing the number of ani-
mals that may be affected by the proposed impound-
ments.ADF&G (1982e)examined the relationships
between the home ranges of radio-col 1 ared brown
bear during 1980-1981 and three arbitrarily chosen
areas that included:(1)the proposed impoundment,
(2)a 1 mile (l.6 km)zone around the proposed
impoundments,and (3)a zone occupying areas 1 to 5
mil es (1.6 to 8 km)from the proposed impound-
ments.
The mean ,overl ap of the home ranges of 19 brown
bears with the impoundment was 5 percent (range of
0-25 percent),for the I-mile (1.6 km)zone it was
15 percent (0-48 percent).and for the 5-mi 1e (8
km)zone it was 52 percent (0-100 percent)(ADF&G
1982e).These figures under-represent the actual
use by brown bears of the area in and adjacent to
the impoundment area because the home range figures
used in calculating the percent overlap are the
total annual home ranges.Seasonal use by brown
bears.particularly during the spring,is more
i ntensi vee
Analyses of the proximity of relocations to the
proposed impou ndments simi 1 arly show that radio-
collared brown bears selectively use areas that are
close to the Susitna River~particularly during the
spring period.Comparisons of the number of bear
relocations in the impoundment areas,as well as in
the two "impact"zones discussed earlier,indicate
that use in the actual impoundment area was greater
E-3-334
-.
4.2 -Baseline Description
The age composition of brown bears captured in the
middle Susitna Basin duri[1g 1980-1981 was 19.6 per-
cent cubs,11.8 percent yearlings,12.1 percent
two-year olds,15.7 percent three-and fou r-year
olds,and 39.2 percent adults.The moderately high
percentages of young animals in the Susitna brown
bear population suggest that the po~lation is
you ng and produ ct i vee
E-3-335
4.2 -Baseline Description
-Productivity
The mean litter size for brown bears in the middle
Susitna Basin was 2.3 (range of 1 to 3),based on
nine 1itters of newborn cubs observed with radio-
collared females since 1978 (ADF&G 1982e).The
mean litter size for the basin is comparable to
those in highly productive brown bear populations
on Kodiak Island and on the Alaska Peninsula,and
is higher than litter sizes in the relatively un-
productive Brooks Range brown bears (Table
E.3.111).
Of 10 cubs in 5 known·1itters produced in the
middle Susitna Basin during 1981,3 (in 3 litters)
were lost during the summer of 1981 (ADF&G 1982e).
One of these losses may have been capture-related.
Tait (1980)has suggested that abandonment of
litters of single cubs may be an adaptive strategy
for brown bears.Physical evidence (1 actation)
suggests that another bear may have had a litter in
1981,but cubs were never observed;they may have
been lost prior to the recapture of this bear
during summer 1981.In 1979,studies showed that
two cubs in a litter of 3 were lost as were 2 year-
1 ings or cubs in a another 1itter of 3.No other
losses from yearling or 2-year-01d litters were
observed,suggest"ing that offspring mortality is
concentrated on cub classes.Causes of cub losses
were not determined,but predation by male brown
bears was considered most probable (ADF&G 1982e).
Compari sons of the reproductive rates of brown
bears in the middle Susitna and Ne1china basins
with reproductive rates of other brown bear popula-
tions indicate that the Susitna-Ne1china Basins
support some of the most productive brown bear
populations in Alaska (Table E.3.112).
-Dispersal
ADF&G (1982e)believed that dispersal of sub-adult
brown bears,both to and from the study area,was
probably common.Several instances of dispersal by
radio-collared brown bears were recorded.One
male,originally tagged as a 2-year-old in 1978 on
the Susitna River north of the Denali Highway,was
recaptured and radio-collared near C1 arence Creek
on the Su sitna Ri ver.Another 2-year-01d mal e was
E-3-336
4.2 -Baseline Description
captured near Deadman Creek during the sprinQ of
1981 and mvoed downstream (54.9 miles,88.5 km)to
the vicinity of Moose Creek.During the fall,the
same animal moved back to the vicinity of Sherman
and Curry.The importance of dispersal in
maintaining brown bear population levels in the
Susitna River basin and in adjacent river drainages
is not known.
-
-
(e)
-Sport Harvest
ADF&G harvest data for brown bear in GMU 13 are
presented in Table E.3.113 (ADF&G 1982e).From
1973-1980,harvests averaged 64/year (44-84).The
mean age of brown bears taken du ri ng the peri od
1973-1980 was 6.5 years (6.3 for males and 6.8 for
females).This relatively young age suggests that
many GMU 13 hunters are not selecting large trophy
bears.Of 656 bears that have been harvested and
aged in GMU 13 du ri ng the peri od 1970-1980,10
percent were yearlings,29 percent were 2-years-old
or less,41 percent were 3-years-old or less,and
52 percent were 4-years-old or less (ADF&G 1982e).
In recent years,sport hunters have appl ied pres-
sure to extend brown bear seasons and bag limits in
GMU 13.This pressure has largely resulted from
research showing that brown bears are a major pre-
dator on moose calves (Ballard et al.1980,1981a).
In addition,Mi 11 er and Ball ard (1980)suggest that
there may be a harvestable surplus of brown bears
in GMU 13.
Black Bear
-
All site-specific information on black bear populations in
the Su sitna Basi n was obtai ned from the recent study by
ADF&G (1982e)during 1980-1982.Most of the data for 1981-
82 was for the middle Susitna Basin (upstream from the Devil
Canyon damsite),but the studies now underw<l.Y are al so
focusi ng on bears downstream from Devil Canyon.
(i)Distribution
Black bears are the most common and widely distribu-
ted of the three bear species in North America.They
occur inmost areas of Al aska as far north as the
Brooks Range.Black bears are highly adaptable and
are able to utilize a wide variety of habitats.Like
brown bears,they are omnivores and their ranges and
diet respond to regional and temporal changes in foodrava"il abil ity.Prime bl ack bear habitat can be
E-3-337
4.2 -Baseline Description
generally characterized by relatively inaccessible
forested terrain,thick understory vegetation,and
abundant sources of plant foods such as succulent
herbs and forbs,berries,and fruits (Pelton 1982).
B1 ack bears appear to be moderately abu ndant in the
middle Susitna Basin.However,because of the limi-
ted distribution of suitable habitats,black bears
generally occu I"only ina narrow fri nge of forested
habitat along the Susitna River.
-Seasonal Movements
Based on relocations of 53 radio-tagged black bears
during 1980-81,ADF&G (1982e)described the prob-
able seasonal movements of black bears in the
middle Susitna Basin as follows.In years of nor-
mal or abundant berry crops,many bears move in
late summer,to somewhat higher country adjacent to
the spruce habitats along the river,returning to
their spring and early summer home ranges near the
river to den.Most of these late summer movements
are upstream (east)and in a northerly direction
(ADF&G 1982e).In years of subnormal berry crops,
most individuals make more extensive movements,
movi ng long di stances upstream or downstream ; n
search of acceptable foraging areas or areas where
salmon are available.These movements occur
primarily along the main Susitna River,indicating
that it is a main transportation corridor.Most
individuals making these extensive movements return
to their former home ranges,but some do not.In
late summer and fan,particularly during poor
berry years,these extensive movements of bl ad
bears may bri ng them in close contact with brown
bears,possibly resulting in increased mortality of
black bears through inter-specific predation (ADF&G
1982e).
Females with newborn cubs are exceptions to this
general pattern of seasonal movements.Femal es
with cubs make less extensive movements than other
bears regardless of the berry crop.
-Denning
Distributions of den sites of black bears in the
Susitna Basin indicate that dens occur most common-
ly in steep terrain along the main Susitna River
and its tributaries (ADF&G 1982e).However,the
band of acceptable denning habitat appears to
E-3-338
.....
4.2 -Baseline Description
become narrower and more confined in upstream areas
where dens are restricted to the immediate vicinity
of the Su sitn Ri ver.
Black bear dens in the Susitna basin were generally
located on moderately sloping hillsides;the mean
slope of 15 dens located during 1980-1981 was 36°
(range of 18°_53°).Half of the dens were located
on south-faci ng slopes,and the remai nder were on
east-to north-facing slopes.
Black bears in the middle Susitna Basin generally
denned at elevations between 1499 feet (457 m)and
2500 feet (762 m).The average elevation of 16
dens between Tsu sena Creek and Devil Canyon was
2178 feet (664 m)(range 1400-4340 feet,
427-1323 m).The average elevation of 13 dens in
the vicinity of the proposed Watana impoundment was
2179 feet (664 m)(range 1801-2749 feet,
549-838 m).Two black bears denned downstream from
the Devil Canyon site during 1981.
Of the 14 dens located during 1980-1981,8 were in
natural cavities and 6 were excavated.All of the
dens in natu ra 1 cavities and 1 of the excavated
dens had been used pri or to the wi nter of 1980-
1981,and 4 of the dens were used again by radio-
collared bears during the winter of 1981-1982.In
contrast,black bears on the Kenai Peni nsu 1a were
rarely found to reuse dens during successive years
(Schwartz and Franzmann 1981).ADF&G (1982e)
suggest that the relatively high reuse of dens by
black bears in the Susitna Basin may indicate a
scarcity of acceptable den sites and/or habituation
to speci fi c sites •.
Radio-collared black bears in the middle Susitna
Basin entered dens in mid-September to mid-October
1980 and exited dens in early April to mid-May
1981.During,the fall of 1981,black bears entered
dens about 2 weeks 2arlier than in the fall 1980,
probably as a result of the 1981 berry crop failure
(ADF&G 1982e).
-
(i i)Habitat Use
Habitat use by black bears in the middle Susitna
Basi n appears to be simil ar to general use patterns
reported elsewhere in North America,where black
bears most commonly inhabit forested areas with dense
E-3-339
4.2 -Baseline Description
understory vegetation (Jonkel and Cowan 1971,Fuller
and Keith 1980).Of 908 aerial observations of 53
bears in the Susitna Basin,black bears were most
often located in shrubland (42.7 percent of observa-
tions)and spruce (39.4 percent)habitats (Table
E.3.114)(ADF&G 1982e).Use of spruce habitats
remained high throughout the year but was IT1Jch less
prevalent during the summer months.IAlring August,
black bears were often present in shrubland habitats
adjacent to the spruce forests.This use of shrub-
1 and areas was thought to be rel ated to seasonal
increases in the avail abi 1 ity of ri peni ng berri es
(ADF&G 1982e).Use of spruce habitats appeared to
differ among male and female bears;of 126 locations
of female bears during the summer period,43 percent
occurred in spruce habitats,whereas of 125 locations
of males,only 30 percent occurred in spruce
habitats.
An examination of habitat use by black bears within
the proposed impoundment area for the Watana dam
showed that deciduous forests and shrubl ands were
used significantly more often than expected.Other
habitat types were used approximately in proportion
to their availability.In the deciduous forest cover
type,closed birch and open birch forests accounted
for all of the locations.Similar habitat associa-
tions were observed in black bear pOJXllations in
northern Alberta (Fuller and Keith 1980).
-Food Habits
Throughout their range in North America,black
bears consume primarily grasses and forbs du ri ng
the spring,soft mast (fruits and berries)of trees
and shrubs-during the summer,and a mixture of hard
and soft mast during the fall.Only a small por-
tion of black bear diets typically consist of ani-
mal matter and then primarily in the form of
insects or carri on.Spri ng is generally a peri od
of food scarcity and bears may often subsi st on
rema i ni ng fat reserves (Rogers 1976).Preferred
high-qual ity foods of bl ack bears are generally
more abu ndant du ri ng the summer,and animal s
develop most of their fat reserves during this
period.
Little site-specific information is available on
the food habits of black bears in the Susitna
Basin.As discussed earlier,berry crops are an
E-3-340
"..
4.2 -Baseline ~escription
important component of the 1ate summer diet,and
movement of black bears into shrubland habitat is
thought to be related to the availability of
berries in these areas.Although plant foods may
constitute the staple diet during most of the year,
black bears may also prey on moose cal ves during
the spring (ADF&G 1982e).Black bear predation on
moose calves is prevalent on the Kenai Pennisula,
where 70 percent of the known predator-caused
deaths were attributed to black bears (Franzmann et
a 1.1980).III ri ng i ntensi ve rad i o-monitori ng of
black bears during May 22 -June 22,1981,one male
bear was observed on one cal f moose kill and one
adult caribou kill.Later in July,the same bear
was observed on a kill of a radio-collared adult
moose.It is not known if the bear had ki 11 ed
these animal s or if it was scaveng;ng ki 11 s of
another predator.
-Home Range
During 1980,the-mean home range size of 20 black
bears in the middl e Su sitna Basi n was 7616 acres
(31 km 2 ),3968 acres (16 km 2 )for 10 females
and 11,392 acres (46 km 2 )for 10 males.IlIring
1981,however,the average home range size was
53,888 acres (218 km 2 ):49,408 acres (200 km 2 )
for 11 femal es and 57,792 acres (234 km 2 )for 12
males.Although the large increase in home range
s;ze between years may be partly rel ated to the
greater number of observat ions of bears du ri ng
1981,ADF&G (1982e)suggests that the 1arger home
ranges may refl ect the rel atively poor berry crop
during 1981 and the subsequent need for black bears
to move greater distances to find suitable foraging
areas.The observation of black bears north of the
Denali Highway (a rare occurrence)during 1981
supports the suggestion that black bears made
atypically long movements during the summer of 1981
(ADF&G 1982e).Comparisons of home range sizes of
black bears on the Kenai Peninsula (4096 acres
[16.7 km 2J for females and 24,192 acres [98 km 2
for males)(Schwartz and Franzmann 1981)with those
of black bears in the Su sitna area suggest that
home ranges of black bears in the middle basin are
1arge.
E-3-341
4.2 -Baseline Description
The proximity of black bear home ranges to the pro-
posed imp~Jndments suggest that black bear distri-
butions are closely associated with lower elevation
habitats along the Susitna River.ADF&G (1982e)
del i neated two arbitrarily chosen zones arou nd the
proposed impoundment areas (one included all areas
within 1 mile (1.6 km)of the impoundments and the
other included all areas 1-5 miles (1.6-8.0 km)
from the impou ndments)to assess the potential
effects of the impoundments and associated develop-
ment on black bear populations.The mean overlap
of 27 black bear home ranges with the impoundment
areas was 14 percent (0-45 percent).Overlap in
the two adjacent zones was 50 percent (0-100 per-
cent)and 122 percent (56-195 percent)for the 1
mile (1.6 km)and the 1-5 mile (1.6-8.0 km)zones t
respecti vely.
(iii)Population Characteristics
-Population Size
ADF&G (unpublished data)attempted a black bear
census in August 1982 using radio-collared bears
and the Lincoln Index method.The study area in-
cluded all bl ack bear habitat in the middl e basi n
east of High Lake;areas west of High Lake were not
included becau se thi ck vegetation hi ndered si ght-
ability.During the survey flights t 38 black bears
were sighted of which 9 were marked.The popul a-
tion was known to contain at least 21 marked bears t
and thus an estimate of 90 bears (95 percent CI =
50-170)was derived.S.Miller (1982 pers.comrn.)
felt that this estimate was too low t and the tech-
nique will be repeated in spring of 1983.
Productivity
Black bear populations in the middle Susitna
Basin appear to be productive and healthy (ADF&G
1982e).This suggests that habitat is adequate t
even if limited in extent.
Ei ght 1 itters with a total of 16 cubs were ob-
served with radio-collared females during 1980
and 1981 (ADF&G 1982e).Five of these 1 itters
wer::not observed u nt i 1 Ju ne -Au gu st and may
have experienced some losses by this time.Be-
cause of this bias t the observed litter size of
2.0 cubs/litter may be a slight underestimate.
The observed litter size for 7 litters of
yearling black bears was 1.9.
E-3-342
.....
....
.....
.....
4.2 -Baseline Description
Litter si zes in the Su sitna Basi n appear to be
similar to those reported·for 1 itters in other
parts of North America.The mean litter size for
black bears on the Kenai Peninsula was 1.9 cubs/
litter,based on radio-collared animals (Schwartz
and Franzmann 1981). Erickson and Nellor (1964)
reported an average litter size of 2.15 for black
bears in Michigan and 2.0 for Alaska (the exact
locale was not identified).Jonkel and Cowan
(I971)documented litter sizes of 1.5-1.8 cubs/
litter for a relatively unproductive black bear
population in Montana over a several-year
period.
Although cub production appears to be quite high
in the SUsitna.Basin,cub loss also is high •
Based on only 4 litters that were observed prior
to Ju ne 1981,4 of 9 (44 percent)cu bs were lost.
No losses of cubs from litters were observed on
the Kenai Peni nsul a (Schwartz and Franzmann
1981).The high rates of cub loss in the Susitna
Basin are believed to be related to the vulner-
ability of cubs to predation by brown bears and
to the relatively high black bear densities (and
intra-specific competition for suitable habi-
tats)(ADF&G 1982e).
ADF&G (1982e)suggests,on the basis of available
productivity indices,that the Su sitna
pOp.Jlations are not as productive as black bear
populations on the Kenai Peninsula.This was
based primarily on the older age of reproductive
maturity in the Susitna Basin and the high rate
of cub loss.
-Dispersal
Dispersal of black bears from the middle SUsitna
Basin may contribute to bear pOj)Jlations in adja-
cent areas.Dispersal of bears into the Susitna
Basin appears less likely,however,because of the
apparently saturated'nature of black bear habitat
along the SU sitna Ri ver (ADF&G 1982e).Several
instances of dispersal from the study area have
been ~ocumented.One sub-adult male was captured
at Clark Creek and was later shot near Hurricane on
the Parks Highway.A 4-year old male was captured
north of the Susitna River and was later shot in an
area 44 mil es (72 km)to the south.Three adu 1t
black bears moved downstream from the middle
E-3-343
4.2 -Baseline Description
Susitna Vall ey to areas downstream from the Devil
Canyon damsite.Two of these bears denned in the
downstream areas.
-Sport Harvest
Based on Alaska Department of Fish and Game records
for the 1973-1980 period,black bear harvests for
GMU 13 averaged 66/year (range 45-85)during a 365
day season with a bag 1 imit of 3 bears (cubs and
fema1 es with cubs excluded from 1ega1 bag 1 imit)
(Table E.3.115)(ADF&G 1982e).Males constituted
74 percent of spri ng harvests and 65 percent of
fall harvests.Most of the harvest (74 percent)
occu rred in the fall season when bears were taken
incidental to moose or caribou hunts.
The current harvest is well below the sustainable
harvest 1eve1.At present,it appears that few
hunters sufficiently prize black bear meat or pelts
from GMU 13 to charter an ai rcraft to hunt away
from the road system;only 35 percent of the
hunters taking black bear during 1973-1980 recorded
aircraft as their primary means of transportation
(Table E.3.115).However,it is probable that the
increasingly restrictive seasons and conditions for
moose and ca ri bou hu nt i ng in GMU 13 wi 11 resu It in
increased black bear hunting in this area,espe-
ci ally as more hu nters become aware of the exi s-
tence of substantial black bear pO('J1ations in the
unit.
Recorded black bear harvests in the Susitna study
area during 1973-1980 averaged 8/year (a range of
1-15).In general,black bear harvests have been
i ncreasi ng in recent years with the 1argest recor-
ded annual take occurring in 1980.The largest
harvests have occurred in the downstream region of
the Susitna River between the Indian and Talkeetna
rivers,the only portion of the study area current-
ly accessible by river boat or highway vehicle.
(f)Wolf
Wolves in GMU 13 have been the focus of many studies and a
subject of controversy for over 30 years (Ballard 1981).
The history of GMU 13 wolves between 1957-1968 is summarized
by Rausch (1969).From 1948-1953,poisoning and aerial
shooting by the federal government reduced wol f pOPJl ations
to low levels.By 1953,only 12 wolves were estimated to
E-3-344
.-
4.2 -Baseline Description
remain in the basin.The pOp.!lation expanded to a peak
number of 400-450 by 1965 after federal predator control
efforts were curtailed (Rausch 1969).Moose pOp.!lations
declined to low levels in the area,stimulating a series of
predator-prey interaction invest i gat ions begi nni ng in 1975
(Stephenson 1978,Ballard and Spraker 1979,Ballard and
Taylor 1980,Ballard et al.1980).Wolf control efforts
were renewed in 1976-1978,but by 1980,the wolf pOp.!lation
had returned to pre-control levels (Ballard 1981).Recent
data on wolf distribution,habitat use,pOp.!lation charac-
teristics,and detailed histories of individual wolves and
thei r packs are provi ded by ADF&G (I982f).
(i)Distribution
At least.19 wolf packs were known or suspected to be
utilizing the SUsitna Basin in 1980-1981 (Figure
E.3.98).At 1east 6 and possibly 7 of these packs
occur adjacent to the Susitna impoundment.
Individual wolf packs have establ ished territories
which,as indicated in Figure E.3.98,overlap little
with adjacent packs (ADF&G 1982f).However,because
of the large harvest of wolves in this area,packs
are periodically eliminated,and areas with no wolves
exist for varying periods of time until new packs are
formed by animal s di spersi ng from adjacent areas.
ADF&G (I982f)provided detail ed hi stories of pack
formation,membership changes,and disintegration for
.6 packs,beginning as early as 1977.These data
indicate that pack territories appear to be more
stable than membership (i.e.,that a pack is defined
by the area it defends rather than its si ze or
individual members).This may be the direct result
of the destab"ilizing influence of extended heavy
hunting and trapping and the removal of key indivi-
duals from pack structure.
Dur"ing the summer,activities of packs conta"ining
breeding adults are centered on den and rendezvous
sites,the latter being above-ground sites where the
pups play and are fed from the time they are about 2
months old.Figure E.3.99 shows the locations of
known dens and rendezvous sites in the Susitna Basin.
Dens are generally but not always roughly centered
withi n a pack I s territory,and each is frequently
used for more than 1 year.Average distance between
35 dens in the Su sitna and adjacent areas was com-
puted to be 28.1 mil es (45.3 km)(ADF&G 1982f),a
distance that compares well with 24.9 miles (40.2 km)
observed in the Brooks Range of Al aska (Stephenson
and Johnson 1973).
E-3-345
4.2 -Baseline Description
(ii)Habitat Use
Habitat types used by wolves vary widely (Paradiso
and Nowak 1982)and in any particular area are
probably determi ned 1argely by the habitat of their
major prey.In the Susitna Basin~detailed data on
habitat use were collected for the Watana pack
between April 1980 and November 1981.This pack used
a wide variety of habitats but was most frequently
encou ntered in shrub and spruce habitat types (ADF&G
1982f).
Wolf dens in the Susitna area are mostly old red fox
dens taken over and dug out by wolves.The majority
are located on slightly elevated sandy areas provid-
ing good drainage.Entrance holes face predominantly
sou th or east.Both dens and rendezvou s sites have
been found in a variety of habitats.Overstory trees
or shrubs at den sites include spruce t aspen,balsam
poplar,paper birch,and willow in densities ranging
from 90 percent cover to very sparse (ADF&G 1982f).
-Food Habits
Food habits of wol ves in the Su sitna area were
studied by both direct observation of kills and
analysis of scats collected at den and rendezvous
sites (ADF&G 1982f).The former method covers all
seasons,whereas the 1atter provides only summer
food habits.
Du ri ng 1980 and 1981~6 radio-coll ared wol f packs
were observed on 83 kill s.Moose compri sed 57
percent of the kills.whereas caribou comprised 33
percent.Other prey,such as snowshoe hare,
beaver~muskrat,and other small mammals made up
the remaining percentage of kills.Calves accoun-
ted for 51 percent of the moose kills,and com-
prised 7 percent of kills of caribou.
Table E.3.116 summarizes wolf summer food habits as
determined from analyses of scats collected at den
and rendezvous sites during 1980 and 1981.Moose
of all ages were the most important summer food
items during both years of study.However.ADF&G
(1982f)suspected that the importance of calf moose
was probably overemphasized by these data.
E-3-346
.....
.....
4.2 -Baseline Description
Predation rates in the Susitna area have been
estimated to average one kill per pack every 5 days
(ADF&G 1982f).Rates vary somewhat with pack si ze
(Ball ard et al.1981b)but do not appear to vary
seasonally (ADF&G 1982f)as has been suggested for
some areas (Peterson 1980).
Studies of wolf food habits in the eastern Susitna
Basin and adjacent areas since 1975 have suggested
that moose are the si ngl e most important food item
(Ballard et al.1981b).Adult moose are taken se-
lectively from August through December~while short
and long yearling moose (moose that are a few
months younger or older than 1 year)comprise a
disproportionate number of January to July kills.
Wolves take relatively healthy moose in winter.
Ballard et ·al.(1981b)found that during severe
winters all ages of adult moose were taken in pro-
portion to their representation in the population~
but in average and mild winters disproportionate
numbers of older adults were taken •
Caribou have comprised between 4 and 30 percent of
wolf kills from 1975 to 1981.Excluding 1978~when
the main body of the Nelchina caribou herd wintered
in the Wrangell Mountains and thus was largely un-
available during winter~the importance of caribou
in the diet of Susitna Basin wolves appears to have
increased.(Wolf diets averaged 18 percent caribou
for 1975 through 1977 in compari son to 26 percent
caribou for 1979 through 1981).Some of the annual
difference in percentage of occu rrence of cari bou
c'ould be attributed to the difference in the loca-
tions of wolf packs studied during these time per-
iod·s in relation to distribution of caribou.Cari-
bou distribution~however~is probably related to
herd size (Skoog 1968).The Nelchina herd reached
a record low of approximately 7500 in 1972.Since
that time~the population has increased to over
20~000.It is suspected that the increase in the
caribou population generally has made caribou more
available to wolves throughout the eastern Susitna
Basin and adjacent areas.If true~this pattern
would suggest that if the herd grows even larger~
cari bou wi 11 become more important as wolf prey.
Assuming wolf pOJXllations in this -area increase
slightly or remain stable~a larger caribou popula-
tion may have some positive benefits for moose~in
that a larger percentage of the wolf kills may com-
prise caribou~relieving the moose pOJXllation of
some predation mortality.
E-3-347
4.2 -Baseline Description
-Home Range
Each of the six wolf packs studied by ADF&G (1982f)
in the Susitna Basin maintained the same home range
during the period that the pack existed as a stable
unit.Wolf packs in this area occasionally defend
their terri tori es agai nst other wol ves,although
i ntru si ons into terri tori es often occu r when the
home pack is not using that portion of the area.
Observed pack home ranges varied in size from
232,960 acres (943 km 2 )to 621,440 acres (2514
km 2 )and averaged 348,800 acres (1412 km 2 ).
(iii)Population Characteristics
Wolves in the Susitna Basin are heavily hunted and
were al so subject to an i ntensi ve control effort by
the Alaska Department of Fish and Game from 1975 to
1978.This control was an attempt to mani PJ 1ate
moose numbers experimentally by reducing predation.
Whether the wolf pOPJlation was at a low level in
1980-1981,when detailed studies related to the
Susitna project began,is unknown.The pOp.Jlation in
the Susitna Basin in 1980-1981 ranged from about 40
in spring after the hunting/trapping season to about
75 in fall when the pups join the hunting adults
(Table E.3.117).
Although there has been lTllch speculation,there is
1 ittl e agreement on the factors that control _wol f
populations.Van Ballenberghe et al.(1975)believed
that pack densi ty,prey abu ndance,and degree of
exploitation varied so lTllch among pOp.Jlations that
the combination of factors controlling one population
might be quite different from those controlling
another.In the Susitna Basin human exploitation is
quite clearly the most important factor.The is no
bag l-imit on harvest of wol ves in GMU 13 and season
is open from August 10 to April 30.In 1981 and
1982,almost hal f the fall popul ation was removed
through legal and illegal winter hunting.Including
wolves taken during the wolf control program from
1975 to 1978,the average yearly harvest from the
Su sitna Basi n and areas immedi ately adjacent (Game
Management Units 13A,13B,and 13E)averaged 38 and
ranged from 26 to 68.Additional large numbers of
wolves were taken illegally in each year (ADF&G
1982f)•
E-3-348
......
....
-
4.2 -Baseline Description
Although there are few specific data,the maintenance
of these high levels of harvest suggest high produc-
tivity in the pop.tlation.ADF&G (1982f)does not
report average 1 itter si ze for the packs they
studied,but their remarks suggest that 6-8 pups were
produced yearly by each pack.High productivity,
both in terms of proportion of adult females that
whelp and litter size,has been demonstrated in other
exploited pOPJl ations both in Al aska and el sewhere
(Rausch 1967,Van Ballenberghe et ale 1975).
The large numbers of PJPs produced each year results
in a large pOp.Jlation of young wolves likely to dis-
perse to other areas.ADF&G (1982f)gives numerous
examp 1es of radi o-co11 ared wolves that moved from one
pack to ano:ther within the basin;wolves that esta-
blished new packs in vacant areas;and wolves that
left the basin entirely.Dispersal of individuals is
often preceded by forays away from the pack home
range and may be precipitated by death of most of the
other pack members through sport hunting or packing.
(g)Wolverine
The wolverine remains one of the most poorly known of the
larger carnivores,and few scientists have attempted to
study wolverines in their natural habitat.Van Zyll de Jong
(1975)states that the reason for this is that the species
is uncommon,highly mobile,and restricted to the more
remote and inaccessible parts of the country.Most
wolveri ne stud i es in North Ameri ca have reported on the
species'breeding biology and other information obtained
from carcasses (reviewed by Rausch and Pearson 1972).
Recent advances in radio-telemetry have resulted in studies
of wolverine movements,habitat use,and home ranges in
northwestern Montana (Hornocker and Hash 1981),northwestern
Alaska (Magoun 1982),and in the middle Susitna Basin (ADF&G
1982g).
.....
-I
(i)Distribution and Habitat Use
Wol veri nes occu r throughout the Su sitna Basi nand
appear to show little preference for specific habitat
types (Figure E.3.100).The lack of use of specific
habitats is most likely related to the scavenging
lifestyle of this species which dictates seasonally
long movements,a relatively large home range,and a
E-3-349
4.2 -Baseline Description
sol itary existence (Hornocker and Hash 1981).Van
Zyll de Jong (1975)states that lithe wo heri ne IS
niche explains the relative rareness of the species
in the comllJJ nity compared to the effi ci ent hunters
among carnivores that act as providers [of carrion],
and it implies a direct relationship between the bio-
mass and turnover of large herbivore pOp.Jlations and
the abundance and distribution of wolverines."The
wolverine's propensity for wandering far and wide,
which increases its chances of finding widely scat-
tered and immobile food,and its well-developed
food-caching behavior are probably al so adaptations
to the scavenger role (Hornocker and Hash 1981).
Food avail abil ity appears to be the primary factor
determining movements and home range sizes of wolve-
rines (Hornocker and Hash 1981;ADF&G 1982g).Breed-
ing activity also influences the seasonal movements
of males,and to a lesser extent,of females (Hor-
nocker and Hash 1981;Magoun 1982).Temperature may
al so influence movements;Hornocker and Hash (1981)
reported that,during the summer,wolverines of both
sexes moved to higher,cooler elevations and traveled
less during daylight hours.In the Susitna Basin,
ADF&G (1982g)reported that changes in wolverine dis-
tribution occurred throughout the year and that food
availability probably influenced these shifts.They
noted a pronounced movement in spring,summer,and
fall to higher elevations where arctic ground squir-
rels,marmots,and ground-nesting birds were abun-
dant.Food is most available in the spring and
summer,and wolverines consume a wide variety of food
at that time (see Wilson 1982).Krott (1959)found
carrion,small mammals,insects and insect larvae,
eggs,and berries in the summer diet.Magoun (1982)
found microtines,ground squirrels,marmots,and
caribou in the spring and summer diets of wolverine
in northwestern Alaska.
Movements to lower elevations during winter are appa-
rently associated with the increased importance of
carrion in the diet during the winter months.During
wi nters of moderate-to-deep snow depths,the lower
elevations along the Susitna River support high den-
sities of moose (ADF&G 1982a).Also,fewer birds and
small mammals are available at higher elevations dur-
ing the winter months (Kessel et ale 1982a).Winter
ground tracking indicated that wolverines were prey-
ing upon microtines,red squirrels,ground squirrels,
and spruce grouse in addition to carrion (ADF&G
1982g)•Both red squ i rrel s and spruce grou se are
E-3-350
-
--
.....
-.
""'"I
4.2 -Baseline Description
restricted to forested areas,and other small mammals
are also most abundant in coniferous and deciduous
forests.
The degree of territorial ism exhibited by wolverines
in an area appears to be related to the turnover rate
of the wolverine population.Magoun (1982)found
that female wolverines in an essentially unharvested
population occupied exclusive home ranges that were
overlapped by those of males.She did not have
enough data to determine whetheradu lt male home
ranges overlapped.Hornocker and Hash (1981)stated
that wo 1 veri ne home ranges in northwestern Mo ntana
overlapped between individuals of the same and oppo-
site sex and cl aimed that terri tori a1 defense was
essentially nonexistent.However,they were unable
to establish the 'residency status of individuals in
thei r popul ati on.Magoun (1982)reported that fe-
mal es with overl appi ng home ranges mi ght be mother/
daughter combinations,and that young males which
have not yet dispersed might be overlapped by resi-
dent adult males.The data obtained on wolverines in
the Susitna Bas·in indicate that,except for some
overlap between adults and juveniles,individuals of
the same sex occupy mutually exclusive home ranges.
The overlap of ranges shown in Figure E.3.100 is
caused mostly by the mortal ity of some of these
animals during the studies.Hornocker and Hash
(1981)suggested that trapping mortal ity in their
study area,while not excessive enough to reduce
population size,may have contributed to behavioral
instability within the population causing a breakdown
in the terri tori a1 system.They po·i nted out that
unexploited mountain lion populations showed a highly
refi ned system of terri tori al ity,whereas exploited
populations were not territorial at all.Exclusive
use of home ranges by same-sex adult wolverines in
the Susitna Basin and northwestern Alaska may~there-
fore,be a reflection of relatively low trapping
mortality.
(ii)Population Characteristics
The home range data obtai ned from the Su sitna Basi n
study and from other studies can'be used to estimate
the number of we 1 veri nes present in the upper and
middle basins.Home range sizes of male wolverines
wi 11 be used in these cal cu 1ati ons,since more data
are available for males than for females.The
average home range size for 5 adult males located at
least 5 times was 101,760 acres (413 km 2 ),ranging
from 34,560 to 154,880 acres (141 km 2 to
E-3-351
4.2 -Baseline Description
628 km2).These ranges were smaller than those
reported for ma 1es by Ma gou n (1982)(mean =172,800
acres [700 km 2J),but simil ar to the 104,320 acres
(422 km 2 )value found by Hornocker and Hash
(1981).
If we assume that wolverines in the 4,032,640 acre
(16,319 km 2 )middle and upper basins use all
habitat types (including rivers,lakes,rock and
ice),and further assume that adult male home ranges
are IT1Jtually exclusive and contiguous,we arrive at
an estimate of 40 adult males in the middle and upper
basins.Reported sex ratios of wolverine kits taken
from dens and of fetu ses do not differ from a 1:1
ratio (Pulliainen 1968;Rausch and Pearson 1972);
therefore,an estimated 40 adult females also occur
in the area.According to Rausch and Pearson (1972),
the effective reproduction of wolverines is 2 kits/
1 itter.Hornocker and Hash (1981)bel i eved that no
more than half of the females on their study area
were reproductively active in each of the five years
of their study,and only 53 percent of mature females
trapped in the Susitna basin were reproductively
active (ADF&G 1982g).About 40 kits are therefore
added to the basin's pOP-llation each year,resulting
in a total summer estimate of 120 wolverines in the
basin.This converts to a density of 1 wolverine/
33,920 acres (1/136 km 2 ).This compares with other
density estimates of 1/233 km 2 in northwestern
Alaska (calculated from Magoun 1982);1/65 km 2 in
northwestern Montana (Hornocker and Hash 1981);1/207
km 2 in British Columbia (Quick 1953),and 1/200
km 2 to 1/500 km 2 in Scandinavia (Krott 1959).
There are probably fewer than 120 wolverines in the
middle and upper basins,since it is unlikely that
wolverines use all areas;and emigration,immigra-
tion,and trapping and natural mortal ity probably
result in a smalle'r population size.Some juveniles
a1so occu py home ranges that do not overl ap com-
pletely with those of adults.
Trapping is probably the main cause of mortal ity
among wolverines in the'Susitna Basin.A total of 27
wol veri nes was harvested from thi s ar,ea du ri ng 1979-
1981;20 du ri ng 1979-1980 and 7 du ri ng 1980-1981.
The low take during 1980-1981 was probably the result
of poor weather and snow conditions.Most trapping
occurs in the accessible periphery of the area.
E-3-352
4.2 -Baseline Description
fIl'lSIlil,
(h)Belukha Whale
.-The belu kha whale is a wi despread arctic and su barct ic ci r-
cumpol ar speci es that inhabits coastal waters.In Al askan
waters,two discrete stocks,a Cook Inlet-northern Gulf of
Alaska stock and a general Bering-Chukchi-Beaufort stock,
have been i dent i fi ed based on mi grat i on patterns,summer
concentration areas,and morphological differentiation
(Sergeant and Brodie 1969,Murray and Fay 1979,Gurevich
1980).No evidence exists to indicate interchange between
the Cook Inlet stock and the Bering Sea stock,and isolation
has been suggested based on morphological differentiation.
-
(i)Distribution and Habitat Use
In winter,belukhas may be found in some of the ice-
free bays in southern Cook Inlet.Some individuals
a pparently range across the northern Gu 1f of Al aska;
sightings of belukhas have been reported from
Shelikof Strait,Kodiak Island,and Yakutat Bay
(Fiscus et al.1976;Calkins and Pitcher 1978;
Harrison and Hall 1978;Calkins 1979;and ADF&G
unj).Jblished data).
Be lu khas aggregate in grou ps of two to several hu n-
dred individuals "in spring and summer seasons.These
concentrations have been attributed to exploitation
of locally concentrated foods,such as anadromous
fish (Tarasevich 1960,Sergeant 1962).Belukha con-
centrations are also apparently associated with poly-
~amous breeding in April and May,with calving
(reported to occur in May through August in brackish
lagoons)and with the subsequent nursing of neonates
(Seaman and Burns 1981).
Most of the Cook Inlet pOj).Jlation moves into upper
Cook Inlet in spring and remains there through ITUch
of the summer.In spri ng and summer,concentrations
develop near mouths of streams and ri vers in the
northern inlet.The largest concentrations occur
annually between the mouths of the Susitna and Beluga
rivers,sometimes ascending the rivers for several
miles.Various species of smelt and salmon,both
out-migrating smelt and returning adults,are the
most likely attractants in Cook Inlet rivers.There
has also been speculation that the mouth of the
Susitna River is a calving and nursing area for
belukhas.
E-3-353
4.2 -Baseline Description
Aerial surveys were flown by ADF&G (unpublished data)
in upper Cook Inlet between May 17 and August 27,
1982,to identify the timing and magnitude of belukha
concentrations.Belukhas were concentrated in the
i 111 et south of the Su sitna Ri ver mouth from the date
of the fi rst su rvey through 1ate Ju ne or early Ju ly,
with a peak number of 300 animals counted on June 11.
As explained below,these counts may be one third to
one half the actual numbers present.By July 8,the
concentrations appeared to have broken up and only 7
whales were sighted in the Susitna to Beluga River
area.
No calves were sighted du ri ng these surveys,bu t
ADF&G attributed this to the low visibility in the
turbid waters of the upper inlet and indicates that
calves were likely to have been present when surveys
began on May 17.
(ii)Population Characteristics
Population estimates of the Cook Inlet stock from the
mid-1960s indicate 300-1000 belukhas in Cook Inlet,
with an estimate of 500 animals (Klinkhart 1966)most
accepted.More recent surveys su pport thi s estimate
(Calkins 1979;Calkins,unpublished data).ADF&G
(unpublished data)reported 300 belukhas from direct
counts "in upper Cook Inlet on June 11,1982,and
indicated that,because the turbid water obscured the
observers'vision,2 to 3 times that many may have
been present but could not be observed.
4.2.2 -Furbearers
(a)Beaver
(i)Distribution and Habitat Use
Beavers are common and widely distributed throughout
much of North America.They occur throughout the
Su sitna Ri ver drai nage,from Cook Inl et upstream
along the river,its tributaries,and ponds to eleva-
tions above 3281 feet (1000 m)(Gipson et ale 1982).
They are herbivorous and eat herbaceous and aquatic
vegetation as well as the bark,twigs,and stems of
trees and shru bs.
The Su sitna Ri ver from Devil Canyon to the Delta
Islands was surveyed for beaver sign in the summer of
1980 by Gi pson et ale (1982).Use of the river by
beavers increased progressively downstream from Devil
E-3-354
r-
,....
-,
I
..-
...
.-
"""'
4.2 -Baseline Description
Canyon (Gi pson et ale 1982).An overfl ight of the
river in the summer of 1981 and intensive surveys in
1982 confirmed this observation (Table E.3.118).No
beaver lodges,food caches,or dens were observed
within the active floodplain between the Tyone River
and Devil Canyon,but they do occur on some tribu-
taries and lakes in the middle bas"in.In summer
1982,Gipson et ale (unlXlblished data)surveyed the
river downstream from Devil Canyon using a river
boat,hel icopter,and grou nd su rveys to determi ne
beaver habitat preferences,lodge construction mater-
ials,and forage plants.Preferred food sources were
willow (particularly feltleaf willow),balsam poplar,
and paper birch.Alder was the primary material for
lodge construction but was rarely found eaten
(peeled).Peeled birch,poplar,and willow were also
used forconstructi on •
The Su sitna Ri ver between the Deshka Ri ver and Por-
tage Creek was divided.into three sections on the
basis of river morphology and vegetation characteris-
tics:upper section from Talkeetna to Portage Creek,
middl e section from Goose Creek to the Tal keetna
River,and lower section from the Deshka River to
Goose Creek.Each section was divided into linear
miles of floodplain parallel to the main channel,and
each sample unit was one of the mi 1e sections from
the thalweg (the deepest part of the channel)to the
active floodpla"in boundary on one side.Beaver habi-
tat was classified into four categories for analysis
as described below.Although described in terms of
water type,habitat al so included bank characteri s-
tics,water sources,and tree and shrub vegetation.
-Main Channel:Consisted of the major river thalweg
and associated land masses.Channels were charac-
terized by rocky and eroding banks with high velo-
city and high volume flows.
-Side Channel:Consisted of channels which split
off the main thalweg,yet carried large volumes of
water.Representative channels showed rocky banks
and silty flow with generally high velocity.Sub-
stantial amounts of erosion were often associated
with side channels.
-Sloughs:Lower volume and slower flow charac-
teri zed these channel s.Si lty banks with estab-
1i shed vegetation were characteri st ic along with
reduced erosion.The water source was
E-3-355
4.2 -Baseline Description
predominantly the Susitna with some clear-water
mixes.A number of sloughs may exist only at
normal or high water levels.
-Clear water:This habitat consisted of creeks,
river runoff,and seeps which were of non-Susitna
or filtered clear water.Slow to moderate flow,
si1ty banks,and estab 1i shed vegetat i on were
characteristic.
In all sections of the river,beaver were found to
prefer slow-moving side channels or sloughs,as well
as mouths of tributaries (see Table E.3.ll8).Such
sites increase progressively downstream as the river
channel becomes more braided.Beaver in the middle
and lower sections are reported by residents to use
bank lodges which have an underwater entrance and an
air vent under a large tree.If this is the case,
the "high activity"values in Table E.3.ll8 for these
sections are low,since there is no-detectable sign
for these types of dens that would have been
recorded.
Slough and Sadlier (1977)identified the major compo-
nents important to beavers as water depth,stability,
and flow rate and distance to suitable food species.
They found that the variables which correlated best
with beaver pOjJJlation densities were low flow,low
gradient (low erosion potential),and banks contain-
ing a high percentage of food speci,es.Results of
the 1982 survey agree with their work as well as the
findings of Boyce (1974)and Hakala (1952),who
reported that beavers in Alaska favor lakes or slow-
moving streams bordered by subclimax stages of shrub
and mixed conifer-deciduous forests.The results
a1so agree with a study by Retzer (1955)who fou nd
that beavers avoid large rivers·with narrow valleys
and high velocity flows.
(ii)POp,llation Characteristics
Aerial surveys of food caches in the fall have been
shown to be an accurate method of determining the
number of active beaver colonies in an area (Hay
1958,Machida 1982).An aerial cache survey conduc-
ted by Gipson et ale (unjJJblished data)in 1982
revealed 14 beaver food caches in the active flood-
plain of the Susitna River between Portage Creek and
Talkeetna (0.26/mile [0.16 caches/km]).Each cache
is estimated to support five beavers (Boyce 1974),so
the pOjJJlation of that stretch of the river is
E-3-356
4.2 -Baseline Description
estimated at 70 beavers.This is a low pO(lJlation
density compared to a range of 0.56 -0.65/mile
(0.35-0.40 colonies/km)found elsewhere in Alaska
(Boyce 1974),bu t was expected to be low becau se of
the scarcity of side channels and sloughs with slow-
moving water along this reach of the river.Beaver
densities would be ITlIch higher if beavers in nearby
ponds and tributaries were included,but these areas
are unlikely to be affected by the project and there-
fore were not sampled.PO(lJlationestimates were not
possibl e for the river south of Talkeetna,because
high water levels had obscured or destroyed many of
the existing caches.
The 1982 survey also included Deadman Creek because
of its proximity to the proposed access road.The
density of beavers was 0.85/mile (0.53 active
lodges/km)along the middle portion of Deadman Creek
and was even higher in a marshy section of upper
Deadman Creek (Table E.3.119).An estimated 65
beavers currently occupy this creek.
Beaver pO(lJl ations are productive and can withstand
moderate trapping pressu reo First breeding occu rs at
age 2 or 3,and annual litters average 3 to 4 young
thereafter (Hill 1982).Young beavers disperse dur-
i ng the summer of their thi rd year,sometimes travel-
ing as far as 124 miles (200 km)to set up new lodges
(Hill 1982).Trapping for beaver has historically
been common along the Susit"a River below Devil
Canyon,along major tributaries,and arQund larger
lakes like Stephan Lake (Gipson et ale 1982).
Beavers in alpine areas have seldom been trapped be-
cause of the effort involved.These pO(lJlations are
vu 1nerab 1e to envi ronmenta 1 a lterat i on and/or over-
trapping because of their dependence on small,
isolated riparian habitats (Gipson et al.1982).
(b)rtIskrat
Muskrats are common and widely distributed throughout most
of North America.They occur throughout the Susitna River
drainage from Cook Inlet upstream along the river,its tri-
butaries,and ponds to elevations above 3281 feet (1000 m).
Muskrats are primarily herbivorous,with a diet that
includes pondweed and swamp horsetail (Perry 1982).
The mi ddl e Su sitna Basi n was su rveyed for ITlI skrat si gn in
the early spring of 1980 by Gipson et ale (1982).All lakes
within 3 miles (4.8 km)of the Susitna River were surveyed
by helicopter,from the confluence with the Osh~tna River to
E-3-357
4.2 -Baseline Description
Gold Creek.MJskrat pushups were observed on 27 (26 per-
cent)of the 103 lakes surveyed (Table E.3.120).Most of
the 1akes and ponds with ITU skrat si gn were above the ri ver
valley,between 870 and 2840 feet (265 and 865 m)in eleva-
tion.POPJlations of ITUskrats were also noted along slow-
flowing sections of larger creeks,particularly where lakes
drain into streams (Gipson et al.1982).
A downstream survey of ITUskrat use of Susitna River habitats
conducted by riverboat in the summer of 1980 indicated that
IllJ skrat numbers increase with distance from Devil Canyon
(Gipson et al.1982).Suitable slow-water habitat in
sloughs and side channels increases in availability down-
stream from Talkeetna.No sign of muskrat was noted on the
river between Devil Canyon and Talkeetna.Between Talkeetna
and Montana Creek,si gn of mu skrat was 1imited to sloughs
and marshy areas near the mouths of feeder streams.Muskrat
sign was more commonly observed downstream from Montana
Creek where numerous side channels and sloughs occur (Gipson
et al.1982).
Trapping for ITUskrats has historically been common along the
Susitna downstream from Devil Canyon,along major tributa-
ries,including Indian River and Portage Creek,and around
larger lakes,such as Stephan Lake.Muskrats in alpine
streams and 1akes have sel dom been trapped becau se of the
effort i nvo 1ved.
(c) River Otter
Information concerning the distribution and abundance of
river otters in the middle Susitna Basin was obtained during
autumn aerial and winter ground surveys by Gipson et al.
(1982)(see Tables E.3.121,E.3.122 and E.3.123,and Figure
E.3.101).These data indicate that otters are common along
the Susitna,its tributaries to 3937 feet (1200 m)eleva-
tion,and around large lakes.This distribution is probably
related to the distribution of prey of otters,which
includes primarily fish and crustaceans (Ryder 1955,Knudson
and Hale 1968,Toweill 1974,Gilbert and Nancekivell 1982).
In November 1980,an unusual concentration of otter tracks
was fou nd on the ri ver ice withi n the proposed impou ndment
areas (Gipson et al.1982).The significance of this track
concentration is unclear,but it may represent upriver or
downriver movements of otters prior to freezeup.It is also
possible that the otters were concentrating along the river
to feed on grayling,which were migrating out of the tribu-
taries to overwinter in the Susitna.
E-3-358
r-"'-'~-'
-
4.2 -Baseline Description
~I
-
-
"....
(d)
(e)
Some otter trails were also observed in cross-country
travel,away from bodies of water.Such tracks have been
noted in other areas of south-central Alaska and may
represent dispersing sub-adults (Gipson et al.1982).Local
trappers seldom take river otters because they are
relatively difficult to trap,and the pelt values have
usually not been high enough to justify the effort.
Mink
Mink are locally abundant in the middle basin along the
river,its major tributaries to 3937 feet elevation
(1200 m),and along 1akeshores.Track cou nts from both air
and ground in fall 1980 (Tables E.3.121 and E.3.122)suggest
that mi nk are more abu ndant in the u pper ~eaches (east of
Kosina Creek)of the Watana impoundment area than they are
elsewhere (Gipson et al.1982).Two mink were radio-
collared in 1980,but no data wer~obtained because one
animal slipped its collar and the other1s radio failed.
Food habits of mink vary among areas,depending on prey
availability.Small mammals and fish usually form the
majority of the diet,but crustaceans and birds may also be
eaten (Errington 1954,Wilson 1954,Korschgen 1958).
Muskrats may form a major portion of the diet where they are
available (Hamilton 1940,Sealander 1943).
Marten
Pine marten are common nocturnal mustelids found in spruce
forests throughout i nteri or Alaska.Informati on presented
here is provided by Gipson et al.(1982)from 3 types of
data:(1)radio-telemetry studies of home range,habitat
use and activity patterns of 14 individuals from fall 1980
to fall 1981;(2)snow-tracking data on habitat use;(3)
analysis of food habits from scats;and (4)aerial
snow-track survey data on habitat use and relative density.
(i)Distribution
Aerial surveys of the Susitna River flown in November
1980 i ndi cated that marten were present at 1 east as
far downstream as Portage Creek and as far upstream
as the Tyone River (Table E.3.121)(Gipson et al.
1982).They are locally abundant in the vicinity of
the proposed Devil Canyon and Watana impoundments.
E-3-359
Gipson et al.(1982)found that home ranges of
adult male marten were mutually excl usive but
overlapped those of other sex/age classes.Average
home rang es of 10 rad io-co 11 ared ad ul t mal es were
1,734 acres (7.02 km 2 ).Female home ranges
averaged 915 acres (3.71 km 2 )(n=3),excluding
one animal with an unusually shaped home range.
Bety,een spring and autumn 1981,some marten home
ranges appeared to shift location and vary in size
periodically.Marten rarely swim across rivers or
large creeks,which often form partial home range
boundaries in the study area.
Home range sizes in the Su si tna area are midway
between the figure of 3,136 acres (12.8 km 2 )for
4 marten in Minnesota (Mech and Rogers 1977)and
1,024 acres (4.1 km 2)for 5 marten in the Yukon
Territory (Archibald 1980).Differences in home
range sizes in different areas and seasons are
attr -j b ut ab 1e to v ar i ab il ity of food reso urces
(Lensink et al.1955,Soutiere 1978).
An est imated density of 0.0034 marten per acre
(0.847/krn 2)was calculated from radiotelemetry
data on 10 adult male marten along the Susitna
River between Deadman and Watana Creeks (S.Buskirk
1982 pers.comm.).This estimate assumes a 1:1 sex
ratio,with male and female territories overlapping
and 65 percent juveniles in the population (a
figure derived from trapper harvest data in the
Yukon Territory by Archibald 1980).
Informat i on from former and present trapper s
indicates that marten continue to be economically
the most important furbearer in the vicinity of the
impoundment zones (Gipson et al.1982).
(iii)Habitat Use
Track counts from a November 1980 aerial survey
ind icate that marten are most numerous in coniferous
and mixed forest and woodland and habitats below
1,000 m (3,281 feet)elevation (Table E.3.121)
(Gipson et al.1982).The highest track counts
occurred between Devil Creek and Vee Canyon (Table
E.3.121).
E-3-360
-
4.2 -Baseline Description
Marten resting sites were located below ground in
late autumn,winter,and early spring.In summer,
when soil temperatures are lower than air
temperatu res,marten rest above grou nd.Summer
resting sites could not be characterized because of
the escape response of marten above ground.
Thirty-one of 37 wiltter resting sites (83 percent)
were in red squirrel middens or nests.All were in
forest or woodland vegetation types.
-Food Habits
The diet of marten shows some seasonal variation,
but microtine rodents are the primary prey at all
times of the year in interior Alaska (Lensink et
ale 1955).Microtines had an 88.8 percent frequen-
cy of o'ccu rrence in scats from the mi ddl e Su sitna
Basin (5.Buskirk 1982 pers.corrvn.)(Table
E.3.124).Plant foods,such as bog blueberries,
crowberries,mountain cranberries,and rose hips,
are consumed most frequently in autumn,and atta"j n
an average frequ ency of occu rrence of 23.3 percent.
Bi rd remains were present in 9.6 percent of scats,
most frequently in winter,and squirrels occurred
in 6.8 percent,most frequently in spring.
(f)Red Fox
Red foxes and their sign have been observed throughout the
middl e Su sitna Basi n,including the proposed Devi 1 Canyon
and Watana impoundments.During 1980 and 1981,Gipson et
al.(1982)employed radio-tracki ng,snow-tracki ng,and
aerial snow-tracking to determine fox distribution,abun-
dance,and habitat use.Food habits were studied from scat
analysis,stomach content analysis,and examination of food
remains at dens and on fox trails.Aerial surveys were
conducted to locate fox dens,and dens were surveyed
periodically throughout summer to determine use.
-
(1)Habitat Use
Foxes in the middle Susitna Basin appear to prefer
rel atively high el evation areas near or above the
t imberl i ne (Gi pson et ale 1982).Bl ack spruce fl ats
upstream from Vee Canyon are also commonly·used.
Some foxes use low elevation tributary deltas during
autumn,then shift to alpine zones as snow depth and
volume of water flowing over the ice increase.Other
foxes remain above timberline year round.Trails in
snow indicated that foxes commonly foraged in wi nter
in areas above timberline frequented by large flocks
of ptarmi gan.
E-3-361
4.2.-Baseline Description
In aerial transects of furbearer tracks in fall 1980,
almost twice as many tracks (151 vs.79)were located
south of the ri ver as opposed to the north (Tabl e
E.3.125).This is in contrast to the greater number
of act i ve dens fou nd on the north side.However,at
the upper reaches of the proposed impoundment,fox
density was observed to increase markedly and
transects 1-11 (see Figure E.3.101 and Table E.3.125)
had almost even numbers of tracks on the north and
south sides (67 on the north and 51 on the south).
All of the north side-south side discrepancy is
accounted for in transects 12-14.The south side of
the ri ver above Vee Canyon changes from mou ntai nous
terrain to open,marshy flats which Gipson et ale
(1982)say characterize good fox habitat.
Gi pson et ale (1982)report that searches along the
Susitna River and lower elevations of tributaries in
1ate winter and early spring 1980 produced no evi-
dence of foxes in these areas.Tracks and other
signs were noted on river banks in the following late
fall and early winter.
-Denning Habitats
Nineteen fox dens were located in the middle basin
during baseline studies in 1981 (Figure E.3.102)
(Gipson et ale 1982).Sixteen dens were located
north of the Su sitna Ri ver with several dens con-
centrated in the upper Watana Creek and upper Dead-
man Creek drai nages.Gi pson et ale (1982)report
that several undiscovered dens are likely to exist
on the south side of the river,but the aspect,
physiography,and vegetation appear more favorable
for denning and hunting on the north side.
Dens are typically situated on an aspect facing
south and/or west,and on well-drai ned promi nences
up to 16 feet (5 m)above surrounding areas.Dens
are also characterized by proximity to a lake of
over 10 acres (4 ha)or a creek.Dens were found
between 3280 and 3940 feet (1000 and 1200 m)
elevation in areas of rolling hills adjacent to
mountains.All active dens located were in or near
areas of medium-to-high ground squirrel density.
E-3-362
-
r-n
i
.....
....,
4.2 -Basel ine Description
Foxes in this study area remained at den sites into
October,nuch 1ater than in other areas of Al aska
(see Gi pson et ale 1982)or el sewhere (Shel don
1950,Storm 1972).Foxes in the Su sitna project,
area appear to use den sites throughout the winter,
as evidenced by clearing of snow from at least one
entrance of most dens visited by observers during
winter months.
-Food Habits
Principal foods of foxes in the middle Susitna
Basin were determined by Gipson et ale (1982)
through direct observation of foxes,identification
of remains at dens and on trails,scat analysis,
and stomach analysis of foxes taken by trappers.
In spring and summer,diets include arctic ground
squirrels,red-backed voles,and singing voles.
Ptarmigan are taken throughout the year and are
major components of the diet in winter.Muskrats
are taken where available and may be relatively
important tQ foxes in the vicinity of large lakes
such as Stephan Lake,Cl arence Lake,and Deadman
Lake.Di spersi ng you ng mu skrats and mu skrats at
pushups are especially vulnerable to predation by
foxes.
Carrion is also identified as important by Gipson
etal.(1982)based on the observations of foxes
feeding on a carcass of moose and another of
caribou near Watana Camp and on a sheep carcass on
the east fork of Watana Creek.
Snowshoe hare are presently scarce in the Su sitna
study area and are,therefore,unimportant in the
diet of foxes there.The scarcity of hares may be
responsible in part for the relatively low number
of foxes in the area,as well as the seasonal
shifts by -foxes to higher elevations where
ptarmigan are available.
-Home Range
Summer home ranges vari ~d from 4544-8064 acres
(18.3 to 32.7 km 2 )in the Su sitna study area with
little difference in home range size between males
and females (Gipson et ale 1982).The larger size
E-3-363
4.2 -Baseline Description
of home ranges in the Su sitna study area compared
with studies in midwestern states was attributed by
Gipson et al.(1982)to the greater availability of
food in the midwest.
(ii)Population Characteristics
Si x of 19 dens fou nd ina 432,640 acres (1751 km 2 )
area in the middle basin in summer 1981 were active
(Gipson et al.1982).Dens were classified according
to size and use as described in Table E.3.126;
locations are mapped on Figure E.3.102.A seventh
den was probably also active,giving a density of one
family per 61,440-72,320 acres (250-292 km 2 )(a
family usually consists of 4-6 foxes).Gipson et al.
(1982)report that the most reasonable estimate of
density is one fami ly per 20,480 acres (83 km 2 )
based on the assumption that at 1east one thi rd of
active dens were found in 1981.
Transect data demonstrate a marked increased in
number of fox tracks encountered as one progresses
upstream from Devil Canyon to the Tyone Ri ver.Fur
harvest reports of the Alaska Department of Fish and
Game indicate that 983 red fox pelts were exported
from GMU 13 between 1976 and 1981.Four dealer loca-
t ions accou nt for 92 percent of the basi n harvest:
Cantwell,Gakona,Copper Center,and Glenallen.
Cantwell,which lies closest to the study area,com-
prised 11 percent of the totalS-year GMU 13 export.
Gipson et al.(1982)indicate that interviews with
furdealers and trappers identify the upper Copper
River-Solo Hills-Maclaren River area and the Crossman
lake area west of Paxson as the source of most foxes
taken.Dean Wilson (personnel communication cited by
Gi pson et al.1982)indicated that most of the furs
he buys are taken in open,marshy cou ntry and that
prime fox habitat decreases from the Maclaren River
to the Tyone-Oshetna-Su sitna areas as flat open
plains rise to mountainous alpine terrain.Gipson et
al.(1982)conclude that the Susitna project study
area supports a low-density fox pOJX.Ilation relative
to other areas in Alaska.
(9)Lynx
The distribution of lynx in the middle basin is very limited
at present.Tracks and scats have been found in several
areas including the mouth of Goose Creek (probable lynx
E-3-364
I~
"""
4.2 -Baseline Description
tracks seen from the air on November 19,1980,and a dense
concentration of scats and tracks found on October 22,
1981);the mouth of Jay Creek (tracks seen on October 30,
1981);and along Goose Creek,1 mil e (l.6 km)from the mouth
(tracks seen on November 3,1981)(Gipson et al.1982).
However,considering the amount of effort involved in aerial
and grou nd fu rbea rer su rveys ,these t rac k record sind i cate
that few lynx occur in the middle basin.
In the past,lynx were apparently fairly numerous in the
canyon country of the Susitna River,being found primarily
in the forests along the river (H.McMahan,pers.comm.
cited by Gipson et al.1982).Trappers in the vicinity of
the impoundments reported no sightings of lynx or their
tracks,and reports from trappers in the Gold Creek area
suggest that lynx have been uncommon there in recent years
as well (Gipson et ale 1982).
Lynx population levels fluctuate in response to availability
of snowshoe hares (Keith 1963),which were uncommon in the
Susitna Basin in 1981 (Kessel et ale 1982a).Gipson et ale
(1982)reported that historically,the frequency of natural
forest fi res increased from Portage Creek to the Tyone
River,and speculated that snowshoe hare (and lynx)numbers
may have been higher in the past.However,Kessel et ale
(1982a)note that no fi res have occu rred in the Su sitna
Basin in the recent past,and they report that hare numbers
appear to be chronically low in the Susitnaarea.If fire
or other habitat change leading to an increase in snowshoe
hares occurs,lynx populations will likely also increase.
However,for the present,lynx are uncommon in the area.
-I
(h)Coyote
The distribution of the few coyotes occurring in the middle
basi n is generally 1imited to those areas downstream from
Devi 1 Creek.No coyotes or thei r tracks were observed by
Gipson et at.(1982)during baseline studies in the Susitna
area,although several sightings of coyotes in fall 1980
were reported to them.Other sightings of coyotes,or their
tracks,have also been reported in the Gold Creek and Canyon
areas (H.Larsen 1981 pers.comm.;R.Roull ier 1981,pers.
comm.cited by Gi pson et al.1982).Coyotes have not been
seen or taken by trappers upstream from Devil Creek.The
distribution and abundance of coyotes in the Susitna area is
probably 1 imited by wolves rather than by habitat,food
avail abi lity,or trappi ng pressure.Wol ves are usually
aggressive toward coyotes within their home range (R.
Peterson and J.Woolington 1982 pers.comm.).
E-3-365
4.2 -Baseline Description
(i)Short-tailed Weasel
Short-tailed weasels are locaily abundant in the middle
basin,and their tracks have been observed in a variety of
habitat types at elevations ranging from the banks of tile
Susitna River to over 4290 feet (1500 m).Transect surveys
conducted in November 1980 yi el ded 746 short-tail ed weasel
tracks,328 (44 percent)of which were counted on a single
transect near the Tyone River (Table E.3.121).Most of the
tracks (489 or 66 percent)were observed in woodland white
or black spruce vegetation types;an additional 190 (25
percent)were counted in medium shrub types (Gipson et al.
1982).It appears that short-ta i 1ed weasel s can meet thei r
food and cover needs in a variety of habitat types.Short-
tailed weasel s have been taken both del iberately and
incidentally by trappers on upper TsusenaCreek,in the Fog
Lakes area,and el sewhere in the study area;but they are
not a species of major economic importance.
(j)Least Weasel
Least weasels occur at least sparsely throughout the middle
basin and may be locally abundant.However,their small
size and secretive behavior makes confirmation of their pre-
sence difficult.Several sets of tracks believed to be
those of least weasels were seen in March 1980 along lower
Watana Creek.The carcass of one least weasel,taken by a
trapper at Fog Lakes,was obtained in February 1981,and a
1 ive 1east weasel was observed near the southeast edge of
proposed Borrow Site A on October 25,1981 (Gipson et al.
1982).The pelts of least weasels have practically no com-
mercial value (Svendsen 1982),and,thus,information from
trapping returns is rarely available to supplement direct
observations.
4.2.3 -Birds
Little was known about the birds of the middle Susitna Basin
prior to initiation of baseline studies for the Susitna
Hydroel ectric Project.Basel ine data on breeding birds of the
mi ddl e basi n presented here are primarily those coll ected and
provided by Kessel et al (l982a,Personal comrrunication,and
unp..rblished data),University of Alaska Museum.Data presented
are from 3 sources:(l)12 -25 acres (10 ha)bird census plots,
(2)ground and aerial census of waterbodies,(3)helicopter
surveys and ground reconnaissance of raptor nesting habitats,and
(4)additional data on species presence and phenology and habitat
use were obtai ned from casual observat ions of investigators and
observations solicited from others working in the region (Kessel
et ale 1982a,1982).These data have been 1iberally drawn upon
E-3-366
-
-
....
4.2 -Baseline Description
to provide ITlIch of the following text.However,additional
information has been incorporated wherever appropriate.
Locations of census plots are shown in Figure E.3.103.Sites
were selected in relatively uniform patches of vegetation that
represented each of the major woody avian habitats present in the
region (Kessel 1979).The alpine tundra plot was selected to
include several of the widespread avi~n habitats of higher
elevations.Each plot was censused 8 times between May 20 and
Ju ly 3,1981 (and 8 times between May 24 and Ju ly 2,1982).
Methods were modified from the territory census method
(International Bird Census Committee 1970).
Locations of censused waterbodies are shown in Figure E.3.104.
Grou nd censu ses of 28 waterbod i es were condu cted between Ju 1y 8
and 29,1981.Each waterbody was censused once by observers
walking the shoreline or canoeing the edges,or by both methods
silTllltaneously.Aer'ial surveys to monitor use of waterbodies
during migration were conducted by helicopter between September 7
and October 4,1980;May 3-26,1981;and September 15 to October
23,1981.The number of waterbodies surveyed varied each survey;
the average was 3.4.Fl ights were made at approximately 50 mph
(80 km/h)and between 100 and 250 feet (30 and 75 m)altitude.
When flocks were encountered,the helicopter circled widely and
slowly for an accurate count and identification.On lakes,the
helicopter followed the shorel'ine for the survey;,a single pass
was made over smaller waterbodies.Large lakes were surveyed in
sections.
Raptor surveys were designed specifically for cliff-nesters
(especially golden eagles,gyrfalcons and peregrine falcons)and
large tree-nesters (especially bald eagles).Information on
other species was obtained incidental to these surveys and during
ground-based plot surveys and waterbody surveys.
Raptor surveys were conducted in the middle basin by helicopter
on July 6,1980 and May 16 and 17,1981 (Kessel et ale 1982a).
All cl iff nesting habitat and stands of large white spruce and
cottonwood withi n approximately 3 mi 1es (5 km)of the Su sitna'
River and its tributaries from Portage Creek (1980)and the
Indian·River (1981)to-the mouth of the Tyone River were
surveyed.The proposed access routes were surveyed on July 3 and
5,1981.[XIring surveys,the helicopter moved slowly past cliff
faces at approximately 30-40 m distance until the face was
considered adequately scanned.In 1980 and 1981,active nests
were visited from the ground between May 20 and July 13,1981.
In addition,all potential appearing peregrine falcon nesting
habitat (e.g.,especially partially vegetated cl iffs)was
examined by helicopter and on foot in June 1981 •
E-3-367
4.2 -Baseline Description
A total of 135 species of birds were recorded in the middle
basin.Their relative abundances (see Appendix 3.E)were largely
a function of habitat availab-i1ity.The most abundant species
in the project'area are common redpoll,savannah sparrow,
whitecrowned sparrow,Lapland longspur,and tree sparrow.
Of the 135 species,15 are ranked as rare in the middle and upper
basin on the basis of current information:4 raptors (osprey,
American kestrel,snowy owl,boreal owl);3 species of ducks
(gadwall,blue-winged teal,ring-necked duck);4 shorebirds (up-
land sandpiper,turnstone spp.,surfbird,sanderling);3 small
land birds (black-backed three-toed woodpecker,western wood
pewee,yellow warbler);and ruffed grouse.Most of these species
were rare becau se they were either at the peri phery of thei r
geographic ranges or were limited by a lack of appropriate
habitat.All 15 species are represented by larger pO\lJlations in
other portions of Alaska.
Baseline data on distribution,abundance,and habitat use of bird
populations in the lower Susitna floodplain were collected by the
University of Alaska Museum (Kessel et ale 1982b).Three types
of avi an su rveys were conducted between Dev;1 Canyon and Cook
Inlet:(1)spring aerial surveys of waterbirds in 1981 and 1982;
(2)a ground survey of all bird species in early summer 1982;and
(3)an aerial survey for bald eagle nests in summer 1982.
Spring aerial surveys were made on May 7,1981,and May 10,21,
and 28,1982.Flights were made with 2 observers and a pilot by
fixed-wing airplane or helicopter at an altitude of 100-200 feet
(30-60 m)between 60-100 mph (95-160 km/h r)•Fl i ght patterns
varied with river morphology to obtain the most complete count
possible.In wider,braided sections,and in the delta,an S-
pattern between the outermost banks was followed.Where the main
channel was spl it,each portion of the channel was su rveyed
separately.Si ngl e,u nbrai ded channel s were surveyed with a
direct flight pattern.
The ground survey was conducted between Curry and the river mouth
from June 10-21,1982.Extensive,uniform patches of each of the
major terrestrial habitats,as sighted from the river,were sur-
veyed each morning on foot.
Su rveys for nesting bal d eagl es were conducted in the lower
Susitna River floodplain in April 1980 by the US Fish and
Wildlife Service,in late June 1981 by TES and on July 1,1982 by
the University of Alaska MJseum (Kessel et a1.1982b).Three
observers and a pilot flew an S-pattern searching for
mature/decadent cottonwood forests,which is favored bald eagle
nesting habitat along the lower river.Nesting habitat was
E-3-368
.-
....
-
,~
....
4.2 -Baseline Description
thoroughly searched from the ai r and an attempt was made to
locate all previously recorded nests.Additional nests were
located du ri ng waterbi rd and grou nd su rveys •
At 1east 82 bi rd s peci es were recorded along the lower Su sitna
floodplain in June 1982 (see Appendix 3.F).
(a)Raptors and Raven
Definitions for raptor "nesting locations"and "nest sites"
are given in Appendix 3.I.
A total of 10 raptor species were recorded upstream from
Devil Canyon.Kessel et ale (1982a)recorded 10 raptor
species upstream from Devil Canyon.Five of these species
(six including the common raven,a functional raptor that
often provides nests for some raptor species)are known to
nest in the area,and at least two additional species
probably breed there (Appendix 3.E).The presence of Broad
Pass to the west and a pass to the east contai ni ng the
Richardson Highway,both commonly used by a variety of
migrating raptors (H.Springer,pers.comm.,D.Roseneau
1982 pers.comm.),and the absence of comparable passes in
the immediate project area suggest that any migratory move-
ments of raptors in the project area would 1 ikely be com-
prised primarily of local breeders.
A total of 53 raptor/raven nesting locations have been
reported from the mi ddl e basi n (White 1974;Kessel et ale
1982a;B.Kessel 1982 pers.comm.;see Table E.3.127).At
least two of these locations (GE-6 and GE-12)do not appear
to exist and probably represent two of the remaining 51
locations (see Table E.3.127).Active nesting locations in
1980 included 6 golden eagle,4 bald eagle,1 common raven,
and 1 nesting location of an unidentified species (probably
gyrfalcon).Active nesting locations in 1981 included 6
golden eagle,5 bald eagle,1 gyrfalcon,2 goshawk (dis-
covered during ground-based plot search),and 4 common
raven.One additional active golden eagle nesting location
was discovered during the course of other work in 1982.
Nesting locations that were not active in 1980 and 1981 pre-
sumably functioned either as alternates or,in some cases,
may be used by additional pairs in years when pOp,llation
levels may be 'higher.Table E.3.128 shows the general
breeding phendogy of golden eagles,bald eagles,gyrfalcons
and ravens in Alaska.These schedules are applicable to the
middle basin.
In 1974,White (1974)found 14 active nesting locations
within the same area of the middle Susitna Basin:
E-3-369
4.2 -Baseline Description
2 gyrfalcon,3 bald eagle,9 common raven.He also reported
a single gyrfalcon at one additional known nesting location
(GYR-1;see Tble E.3.127)and observed 2 single peregrine
falcons that did not apear to be nesting [see Section
4.2.3(a)(iv)J.White (1974)also reported an addition 13
i nact i ve nest i ng 1ocat ions,ascri bi ng 7 to ravens,3 to
golden eagles,2 to bald eagles,and 1 to goshawks.The
apparent change in number of pairs of golden eagles and
ravens present in th mi ddl e basi n between 1974 and 1980 -
1981 may be the result of a combination of several factors,
including differences between observers and survey
intensity,and natural variations in breeding pOp..llation
levels as a result of spring nesting conditions or changes
in prey availability and vulnerability (Kessel et ale 1982a,
D.Roseneau 1982 pers.comm.).
No spec i fi c data on mi gratory movements of raptors were
collected in the middle basin.However,the presence of
Bread Pass to the west and the Ri chardson Hi ghway pass to
the east,both commonly used by a variety of migrating rap-
tors and other birds (B.Kessel 1982 pers.comm.,H.
Springer 1982 pers.comm.,D.Roseneau 1982 pers.comm.),
and the absence of comparable passes in the immediate pro-
j ect area,suggest that mi gratory movements of raptors in
the project area would likely be comprised of local
breeders.
Distribution,abundance,and food habits are discussed beJow
for each species.Although no data were collected on food
habits of raptors in the Susitna Basin,they are unlikely to
differ greatly from raptors in similar situations in other
parts of the state.
(i)Golden Eagle
Estimates of breeding pOp..llations of golden eagles in
south-central Alaska,including the Alaska Range,are
not available.However,this raptor nests at low
densities throughout most of the state,including the
arctic slope,and nesting occurs almost exclusively
on cliffs (Roseneau et al.1981).Golden eagles
regularly build and maintain a number of silTllltaneous
nests,often at locations several kilometres apart,
which are used as alternates in different years
(Brown and Amadon 1968,McGahn 1970,Roseneau et ale
1981).
The abundance of golden eagles in the central Alaska
range is 1 i kely to be lower than that found in the
E-3-370
.-
,fjfi1i1!fl.
.....
-
-
,...,.
4.2 -Baseline Description
mi ddl e Su sitna basi n.In most of the Al aska Range,
cliff-nesting locations for raptors tend to be widely
dispersed (Bente 1981,P.Bente 1982 pers.comm.,D.
Roseneau 1982 pers.comm.).However,if nesting
cliffs are available,pairs of golden eagles may nest
relatively close to one another.Murie (1944)found
golden eagles nesting as close as 1.0 and 1.5 miles
(1.6 and 2.4 km)apart in Denali National Park in
1941 and 1939,respectively.
The abu ndance of acti ve gol den eagl e nesting loca-
t ions present in the mi ddl e bas in in 1980 and 1981
(one pair per 9.18 miles [14.8 km]of river)(Kessel
et ale 1982a)was similar to that found along the
Brooks Ra nge port i on of the Dalton Hi ghway in 1979
(one active nest per 9.73 miles [15.7 km])(Roseneau
and Bente 1979).The latter abundance appears to be
one of the highest reported in Alaska.White et ale
(1977)suggested that local populations of golden
eagles may increase during years of high snowshoe
hare popul ations;however,hares are relatively
scarce in the middle basin in 1980 and 1981 (Kessel
et ale 1982a).Murie (l944)noted that arctic
ground squirrels were a major prey of golden eagles
in Denali National Park in 1939-1941,and these
rodents were abundant in the middle basin area during
the study.
Golden eagles are opportunistic hunters.Diets vary
from region to region according to prey availability
and vulnerability.When available,mammals are an
important component of their diet (up to 70-90 per-
cent by weight),but birds and carrion are also often
important.Nonbreed"jng of golden eagles occurs in
some years,and there is some evidence to suggest
that prey avai 1 ab"il ity may influence breeding success
(Brown and Amadon 1968).
In Alaska,there are few published reports of prey
items fou nd at gol den eagl e nests.COnIDon items
have included ground squ i rrel s,marmots,snowshoe
hares,ptarmigan,ducks,and other waterfowl (D.
Roseneau 1982 pers.comm.)
Occasionally,both arctic and red foxes are taken.
One pair on the Seward Peninsula took as many as 5 -
6 red foxes during the summer,and the fledgling from
that nest attacked a red fox about 2 weeks after
1 eavi ng the nest (D.Roseneau 1982 pers.comm.)•
E-3-371
4.2 -Baseline Description
Pairs nesting along sea coasts also take a variety of
seabirds (both alive and as carrion),including young
gulls and rrurres (D.Roseneau 1982 pers.corrvn.).
Carrion,often in the form of large game animals,may
be particularly important during the early spring and
the fall.Carrion also appears to be very important
to sub-adu It gol den eagl es.Large numbers of sub-
adu 1ts frequ ent the calvi ng and post-calvi ng grou nds
of caribou herds.Up to six sub-adults have been
found feeding at one time on wolf-killed and bear-
killed caribou,and sub-adults occasionally kill
caribou calves (Roseneau and Curabole 1976,Roseneau
et ale 1981).
(ii)Bald Eagle
In Alaska,the majority of bald eagles nest coastally
in southeast,southcentral and southwest Alaska;
these pOPllations may exceed several thousand pairs.
North and west of the Al aska Range,numbers decl i ne
markedly and most nesting is associated with wetlands
in portion of the Yu kon (i ncluding the Tanaa)and
Kuskokwim River drainages (see Roseneau et al.1981).
In total,surveys for nesting bald eagles in the
lower Susitna floodplain discovered 38 nest sites,
some of whi ch u ndou btedly represent alternate nest
sites or alternate nesting locations (see Table
E.3.129).In 1982,the year for which data are the
most complete,only 14 of the 24 nest sites reported
in 1980-81 were relocated,but 14 new nest sites were
found.A few nesting locations and nest sites found
in 1980 and 1981 may no longer exist as a result of
blowdown,bank erosion or beaver activity (see
Roseneau and Bente 1981).Of the 28 total known nest
sites reported in 1982,17 were active and 11 were
inactive.Similar proportions of active versus inac-
tive nesting locations and nest sites have been found
along the Tanana River (Roseneau and Bente 1981).
The amount arrd suitability of bald eagle nesting
habitat and the number of nesting bald eagles in-
creased markedly downstream from Indi an Ri ver (see
Table E.3.129).Most of the bald eagle nesting loca-
tions were concentrated in three sections of the
floodplain:(1)between Talkeetna and the Parks
Hi ghway Bridge;(2)between Kashwitna Lake and the
mouth of the Yentna River;and (3)from Bell Island
to the mouth of the Susitna River (Kessel et ale
1982b).The number of bald eagle nests and nesting
pairs per river mile along the lower Susitna River
floodplain is comparable to that found on the Tanana
River (D.Roseneau 1982 pers.comm.).
E-3-372
-
4.2 -Baseline Description
Bald eagles are opportunistic in their feeding
habits,and diets vary from region to region
according to the avai1abiltiy and viJ1nerability of
prey species.Although they take a variety of live
prey,bald eagles often rely heavily on local sources
of carrion,may be attracted to dumps,and may pirate
prey from other raptors,particularly osprey (Brown
and Amadon 1968).Fish and birds are both important
components of their diet.
In A1 aska,ba1 d eag1 es often rely on dead or dyi ng
salmon when they are available,and take a variety of
other species of fish in shallow water or as carrion
along shore 1i nes.Waterfowl and seab i rds (a 1ci ds,
anatids and1arids)also figure prominently in their
diet,particularly in some coastal regions (e.g.,the
Aleutian Islands).Ritchie (1982)found fish and
avi an prey to have nearly equal frequ ency of occu r-
rence (43.8 and 43.7 percent,respectively)in re-
mains at nests along the Tanana River,Alaska,where-
as mammal remains occurred in 12.6 percent of nests.
Remai ns of Anas spp.(mostly mall ard)constituted 17
of 28 occurrences of avian prey.Dead,dying,or
injured birds are often taken from the water surface,
but eagles are also quite capable of surprising and
taking uninjured waterfowl and seabirds from the
water surface or in the air.Even geese may be occa-
sionally taken in flight (Brown and Amadon 1968),and
sandhi 11 cranes and swans have a1 so been taken (D.
Herter 1982 pers.comm.and A.Springer 1982 pers.
comm.).
Diets of bald eagles nesting along the Susitna River
are probably similar to diets of eagles nesting along
the Tanana River.Salmon are undoubtedly important
to many pairs in late summer and fall.Earlier in
the year,other fish species (particularly whitefish,
suckers and grayling)and waterbirds (especially
waterfowl)constitute the bu1 k of their diet.Snow-
shoe hares and ITU skrats may a1 so be taken on occa-
sion.
-
(i i 1)Gyrfalcon
Gyrfalcons are not abundant in southcentra1 and cen-
tral Al aska,but they rejJll ar1y nest throughout the
Alaska Range.Cade (1960)estimated the total Alaska
population at only about 200-300 pairs.Roseneau et
a 1.(1981)consi dered that·est imate too low,but
doubted that the population exceeded 500 pairs.
E-3-373
4.2 -Baseline Description
Numbers of nesting gyrfalcons may vary considerably
between years (Cade 1960,Roseneau 1972,Swartz et
ale 1975)but variation may be less over larger
regions (Roseneau 1972).The majority of the Alaskan
population is found in northern and western Alaska
(Roseneau 1972,Roseneau et ale 1981),and gyrfalcons
there tend to exhi bit rel at i vely low site fi del ity
from year to year (Cade 1960 and Roseneau 1972).
However,in the Alaska Range,where suitable nesting
cliffs are fewer more widely dispersed,most sites
appear to be used more regularly (Bente 1981).
Gyrfal cons are year-arou nd resi dents of the arcti c
and subarctic and are also opportunistic hunters.
During the summer their diets vary according to prey
ava i 1abi 1 ity and vu 1 nerabi 1 ity (Roseneau 1972),but
they typically rely on only a few pri nci pal prey
s peci es for the bu 1 k of thei r food..
The pri nci pal summer prey speci es include ptarmi gan
(often 70-90 percent by weight of their diet),arctic
ground squirrels,and,in some regions,long-tailed
jaegers (White and Cade 1971;Roseneau 1972).Migra-
tory birds typically constitute no more than 15-20
percent by weight of their summer diet.In some
regions of interior Alaska (e.g.,the Alaska Range),
grou nd squ i rre1s su rpass pta rmi gan in importance
(Cade 1960 and Roseneau 1972).In the winter,gyr-
falcons are almost solely dependent on ptarmigan
(Platt 1976 and Walker 1977),although in some high
arctic regions,arctic hares are also important
winter prey.The year-round rel iance on ptarmigan
and the high utilization of small mammals in the
summer are important factors that have hel ped gyr-
falcons to avoid serious biocide contamination and
thus maintain healthy,non-endangered populations in
the arctic.
Despite the reliance on a few principal prey species,
gyrfalcons are capable of shifting to other food
sources during the breeding season if the availabil-
ity of a few prey species changes dramatically-,-pro-
vided that other prey species are present (White and
Cade 1971;Roseneau 1972).It has al so been sug-
gested that gyrfal cons may not \}reed in some years
when prey availability is low.
E-3-374
r--
-
-
-
-
( i v)Peregrine Falcon
Per eg rine f a1con s are dis t rib ut ed we r 1dwi de.
Peregrines are specialists in avian prey and prey
weights range from 50 g or less to over 600 g.In
Al aska,the 2 endangered races,Falco ,peregrinus
anatum and F .p.sundrius,rely on a broad prey base
consi sting of a variety of shorebirds,waterfowl,
passerines and occassional small mammal s (Cade 1960,
Roseneau et al.1981).'In contrast to gyrfalcons,
peregrines are diverse in their feed ing habits,
concentrating more on categories of prey,such as
shorebirds,than on individual species.Their high
use of migratory prey.(especially shorebirds)on
northern breeding grounds and on wintering grounds as
far south as 30 0 S in South Anerica has contributed to
their endangered status as a result of biocide
contamination.Recently,pollutant residues
(biocides)have tended to decline in peregrine tissue
(A.Springer,unpublished data).Since the late
1970 's,inmost of Al ask and in some other parts of
North Jlmerica,nlIJlbers andproductivity of both
endangered races have increased (USFWS unpubl ished
data).
There were no confirmed sightings of peregrine fal-
cons in the middle Susitna BAsin during 1980,1981,
or 1982,despite the substantial nlll1ber of man-hours
spent on ornithological field work and on raptor
surveys (Kessel et al.1982a;B.Kessel 1982 pers.
comm.).White (1974)saw tWJ individual peregrines
during a June 10-15,1974,survey;however,he found
no sign of nesting.One of the birds was a II s ingle
adult male ...roosting on a cliff about 4 miles up-
river from the Devil Canyon Dam axis,1I and the other
was lI a sub-adult ...about 15 miles upriver from the
Devil Canyon Dam axis.1I .White (1974)stated that the
Yenta-Chul itna-Susitna-Matanuska drainage basin
"seemingly represents a hiatus in the breeding range
of breeding peregrines ...,"and Roseneau et al.
(1981)stated that lithe Susitna and Copper riv:Drs
both provide ...very few ...potential nesting areas for
peregrines .11
The Susitna Ri ver drainage does not provide habitat
typical of or comparable to any important areas of
peregrine nesting habitat in the boreal zone of
Alaska (e.g.,upper Porcupine,upper Yukon-Charley,
E-3-375
~.2 -Baseline Description
middle Yukon,lower Yukon,upper Tanana and Kuskokwim
river drainages).Key elements of the exisitng
habitat in the Susitna River drainage,in addition to
the surveys conducted for them,provide reasonable
evidence that peregrines do not presently nest in the
project area and that biologically significant
numbers of them are unlikely to occur there naturally
in the future with or without project developnent.
(v)Other Raptors
No breedi ng records for owl s were reported in the
middle basin by Kessel et ale (1982a).Three of the
five species of owls (great horned owl,hawk owl,and
boreal owl)that have been recorded in the middl e
basin are year-round residents and probable breeders
in mixed and coniferous forests (Appendix 3 .E).The
short-eared owl occupies open habitats in small
numbers in summer,and a few may breed in the region.
Snowy owls,occasional migrants,are rare in the
middle basin.
Only single records of two species of owls (great
horned owl short-eared owl)were obtained along the
1 ower Su sitna Ri ver du ri ng the spri ng su rveys
(Appendix 3.F).Great horned owl s are 1 ike1y resi-
dents and breeders,especially in mature cottonwood
stands along the river and sloughs.
Suitable nesting habitat for goshawks and great-
horned owl s consi sts primarily of occasional matu re
paper bi rch and paper bi rch-white spruce stands,
which are most commonly found downstream from Devil
Canyon (D.Roseneau 1982 pers.comm.).Some nesting
habitat for other tree-nesting speci es (e.g.,
red-tailed hawks,American kestrels,sharp-shinned
hawks,boreal owls,and hawk owls)and ground-nesting
species (e.g.,merlins,northern harriers,and
short-eared owl s)a1 so occurs in the SU sitna Basi n,
but no concentrated areas of nesting habitat are
known or expected to occur.
The diet of owls and smaller raptors consists mainly
of small rodents and small birds.Northern harriers
feed on either small rodents or small birds in open
terrai n.American kestrel s feed primarily on i n-
sects,small mammals,and occasionally small birds.
Owl s (great-horned owl,short-eared owl,hawk owl),
and boreal owl)are generally specialists on small
E-3-376
"--,
-
-
-
-
-
4.2 -Baseline Description
manvnal prey,though great-horned owls may also take
birds.Sharp-shinned hawks and merlins are
specialists on small avian prey.Goshawks and
red-tailed hawks rely on a combination of small
mammal and avian prey.
(b)Waterfowl and Other large Waterbirds
The middle basin and the lower Susitna River floodplain
above the delta do not support large concentrations of
waterfowl or other waterbirds during either migration or the
breeding season (Kessel et ale 1982a,1982b).Although low,
a vi an use of discrete waterbod i es and waterbody grou ps in
the middle basin varied considerably.An analysis of the
relative importance of discrete wetland areas is included to
identify potentially important areas.
The species composition of waterfowl in the middle basin
showed some differences from that of central Al aska as a
whole,in part reflecting the subalpine nature of rruch of
the study area (Kessel et ale 1982a).Oldsquaw and black
scoter were the most productive of the waterfowl in 1981
(Table E.3.130).Both species are primarily tundra nesters,
and the Alaska Range is the only inland nesting location
known for the black scoter in Alaska (Gabrielson and lincoln
1959).The pintail,one of the most numerous ducks "in
central Alaska,occurred in relatively small numbers in the
study area,in spite of the fact that both 1980 and 1981
were high population years for pintails in Alaska because of
severe drought in the Canadian prairie provinces (King and
Conant 1980,Conant and King 1981).
(i)Migration -Middle Bas;n
The middle Susitna Basin,which is on a high plateau
between the Alaska Range and the Talkeetna Mountains,
does not appear to be a major migration route for
waterbirds t~ontra u.S.Corps of Engineers 1977)
(Kessel et ale 1982a).A relatively small number of
individual s were seen during three surveys in spring
1981 and six and five surveys in fall 1980 and 1981,
respectively (Tables E.3.131,E.3.132 and E.3.133).
Scau p,including both 1esser and greater scau p,were
the most numerous species group during 'both spring
and fall.Relatively large numbers of mallards and
Ameri can wi geon also moved throu gh du ri ng both sea-
sons.Pi nta il s were common du ri ng s pri ng mi grat ion
but uncommon in fall.Few geese or cranes were seen
at either season (Kessel et ale 1982a).
E-3-377
4.2 -Baseline Description
The middle Susitna Basin was less important to
migratory waterfowl in spring than fall (Kessel et
ala 1982a).Because ice breakup does not regularly
occur until mid-May on many lakes in the middle basin
little open water was available to early migrating
waterbirds,such as the dabbling ducks and common
goldeneye.Early migrants used the Susitna River
i tsel f and the thawed edges of 1 akes.Use of the
middle basin's water bodies increased toward the end
of May,concurrent with the availability of more open
water and the influx of the later arriving loons,
grebes,scaup,oldsquaw,scoters,and mergansers
(Kessel et ala 1982a).
The pattern of fall movement in the middle basin was
similar to that known for the rest of central Alaska
(Kessel et ala 1982a).Peak numbers of American
wigeon,pintail,and green-winged teal occured during
the first half of September;loons,grebes,and scaup
during the second and third weeks of September;and
mallards,scoters,buffleheads,and goldeneyes,from
the 1ast thi rd of September to mi d-October.Trum-
peter and whistl ing swan migration occured between
the 1 ast week of September and the end of October
(Kessel et ale 1982a).
(ii)Summer Use of Waterbodies -Middle Basin
The wetlands of the middle basin supported relatively
few waterbirds during the summer.An average density
of only 0.09 adult loons,grebes,ducks,gulls,and
terns/acre of wetlands (22.5/km2)and 0.01 broods/
acre of wetlands (2.9/km2 )were found on 28 inten-
sively surveyed water bodies in summer 1981 (Table
E.3.130).By comparison,a census of 13 waterbodies
in the upper Tanana River valley,similar in size
class distribution to those surveyed in the middle
basin,had average densities of 0.74 adult loons,
grebes,ducks,gulls,and terns/acre of wet-lands
(183.0/km 2 )in 1977 and 0.45 adults/acre
(llO.5/km2)in 1979 (Spindler et al.1981 cited by
Kessel et ale 1982a).Even when gulls and terns are
excluded,the density of broods in the Tanana River
Valley was markedly higher,at 0.03/acre (6.2/km 2 )
than in the middle Susitna basin.Productivity in
the eastern portion of the upper Tanana River valley
study area in 1979 was 30-40 percent lower than his-
torical levels typical of Minto lakes,Tetlin Lakes,
and portions of the Yukon Flats are considered
E-3-378
""'"(
-
4.2 -Baseline Description
among the most productive wetlands in Alaska (J.G.
King,U.S.Fish and Wildlife Service,Perssonal
communications cited by Kessel et ale 1982a).Thus,
the waterbodies of the middle basin appear to support
a relatively impoverished pO[JJlation of waterfowl
during the summer (Kessel et ale 1982a).
As discussed earlier,the species composition of
waterfowl refl ects the su ba 1 pi ne natu re of the stu dy
area with oldsquaw and black scoter (tundra nesters)
bei ng the most produ ct i ve spec i es •Trumpter swan s
al so breed commonly on the eastern end of the study
area,from the vicinity of Oshetna River to at least
the Maclaren River.On an informal flight over ponds
of this area on August 4,1981,Kessel et ale (1982a)
recorded 19 observations of trumpeter swans.Forty
adu It bi rds were seen,i ncludi ng 9 pai rs with broods
(28 cygnets).This are.a is on the western edge of
habitat used by the Tal,keetna Basin trumpeter swan
pOp.Jlation which has more than doubled in the past 5
years (King and Conant 1981).
(iii)Relative Importan~e of WaterBodies -Middle Basin
Kessel et ale (1982a)calculated relative importance
values (I.V.)for each lake surveyed,which combined
3 commonly used measures of habitat quality:number
of birds,density,and species richness.The I.V.
values are ani ndex to the relative importance of
each waterbody included in a particular computation
of the index,and are patterned on concepts presented
by Curtis and McIntosh (1951).The LV.for each
waterbody was calculated each season as the sum of 3
ratios:(l)the mean number of birds per census for
the water body divided by the sum of the means per
census for all waterbodies censused;(2)the mean
density of birds per census on the waterbody divided
by the sum of the means per censu s for all water-
bodies censused;and (3)the mean number of species
per census for the waterbody divided by the sum of
means on all waterbodies.Figures E.3.105 and
E.3.106 compare relative I.V.ratings for all lakes
surveyed in fall 1980 and spring 1981 respectively.
Seasonal pOPllation statistics are listed in Table
E.3.134 for the lakes that had the highest scores.
The following discussions of individual waterbodies
are based on Kessel et ale (1982a).
E-3-379
4.2 -Baseline Description
Stephan and MJ rder Lakes were among the top three
waterbodies in r.V.for all seasons.Stephan Lake
received twice as much use in fall as in spring~and
su pported hi gh numbers of speci es and number of
birds.trltrder Lake consistently supported high
densities.These lakes assumed additional importance
in early spri ng and 1 ate fall because of ice
conditions.trltrder Lake~which reportedly has some
open water all winter~provided some of the first
open water for early spring migrants~as did the
inlet of Stephan Lake;green-winged tea1~mallards~
and pintai1s were using this open water on May 3~
1981.Likewise,these lakes provided the last open
water in fall and were used by the late migrants.
Swans used these lakes during October,as other lakes
in the region became ice-covered.Between 9 and 11
trumpeter swans frequented MJrder Lake between
October 10-18,1981 (J.Ireland 1982 Personal
communication cited by Kessel et a1.1982a);11 to 22
unidentified swans were on Stephan Lake from October
9-23~1981;and 120 swans were there on October 10,
1980.
WB 131~near the mouth of the MacLaren River~consis-
tently supported high levels of waterfowl abundance~
density~and species richness.Its I.V.in spring
was 1 essened by the fact that it was sti 11 frozen
du ri ng the fi rst two s pri ng su rveys.Becau se it was
far from the proposed construction sites~it was not
censused for breeding birds~but a flight over the
lake on August 4~1981~revealed a flock of some 100
molting ducks,mostly scaup,as well as a pair of
trumpeter swans.This and WB 134 were the only duck-
molting lakes found in the basin.A flock of 22 to
42 trumpeter swans congregated to feed on thi slake
throughout the first half of September 1980.
WB 140,east of the Oshetna River~had the highest
I.V.of 28 waterbodies censused during the breeding
season.Not only did it have a high species richness
(11 species)~but it also supported a large number of
birds and had an above-average density.It was also
of above-average importance du ri ng mi gration~even
though it thawed later and froze earlier than most
other lakes.
C1 arence Lake had the fou rth highest 1.V.du ri ng
spring and fall migration,but ws less important
during the summer.It had a relatively high species
E-3-380
~::..--
.....
-
-
-
4.2 -.Baseline Description
richness during all seasons,being used by both
diving and dabbling ducks during migration,but
primarily by divers in summer •
Watana lake was used in fall,especially in 1980,by
mi grant scau p,go 1deneyes,and mergansers du ri ng the
last half of September.Otherwise,it was of little
importance to birds.
Pi stol lake in the lower Deadman Creek area had a
relatively high I.V.in spring because of the number
and diversity of birds it contained after it began to
thaw toward the end of the first week of May.How-
ever,this relatively large lake was only of average
importance during summer,and was little used in
fall.
The southernmost Fog Lake supported high 1evel s of
abundance and species richness during all seasons.
It received 1ess use ins pri ng than du ri ng other
seasons,probably because ice cover was still exten-
sive as 1ate as May 17,1981.On thi s date,ducks
were heavily concentrated in the open water at the
inlet end of the lake.This lake and WB 140 had the,
highest species richness (11 species)during summer.
WB 032,a small lake at the west end of the Fog
lakes,supported a high density of birds in summer
and showed high productivity (at 1 east 4 broods of
horned grebe and 2 of American wigeon seen on July
28,1981).It was not monitored during migration.
Swimming Bear Lake,an alpine lake,received its pri-
mary use during summer.After it thawed in late May,
it was occupied by at least 5 species of waterbirds
(scaup,oldsquaw,scoter,mew gull,and arctic tern),
3 of which were observed with broods on July 29,
1981.Flocks of scaup and white-winged scoters were
seen on the lake during the last half of September
1981.
No ne of the waterbod i es in the mi ddl e bas in had
importance values as high as those calculated for
some of the better wetland sites of eastern interior
Alaska from data obtained during fall 1980 by Ritchie
and Hawkings (l981)(Figure E.3.106)and during
spring 1980 by Ritchie (1980)(Figur~E.3.105).
E-3-381
4.2 -Baseline Description
(iv)Lower Basin
The lower Susitna River above the delta appears to be
little used by waterbirds.Few birds were seen dur-
i ng s pri ng aeri a1 su rveys in either 1981 or 1982
(Table E.3.135),or during the June 1982 ground sur-
veys (see Appendix EF).Few birds have also been
seen on US Fish and Wildlife surveys (see King and
Conant 1981).Overall,swans,white-fronted goose,
scaup spp.,common merganser and merganser spp.were
the most abundant species seen.NUmbers were highest
in the 1ast 37 km of the ri ver between the mouth of
Yentna River and Cook Inlet.
Ice on the lower river apparently broke a week or
more 1 ater in 1982 than in 1981.Du ri ng the May 7,
1981,survey,the river above Talkeetna was breaking
up and carrying a heavy load of ice chunks;whereas
on May 10,1982,this section of river was still
almost entirely frozen.Since spring migration of
dabbling ducks in central Alaska was only 2 to 3 days
later in 1982 than in 1981 (Kessel,unpublished
data),the mai n spri ng movement had passed through
the Susitna region in 1982 before water became avail-
able in the river above Talkeetna.
In addition to early season ice above Talkeetna,the
mai n reasons for the low use of the lower ri ver
appear to be its rapid flow and heavy silt load
(Kessel et ale 1982b).These factors limit the deve-
10lJTlent of aquatic plants and associated inverte-
brates,the main diet of most waterbirds,and make
food invisible,except at shallow edges or in sloughs
(Kessel et al.1982b).Corroborating this assumption
is the fact that the most numerous ducks on the river
were fish-eating mergansers (Kessel et ale 1982b).
(c)Other Birds
(i)Shorebirds and Larids
Seven of the 19 species of shorebirds that occur in
the middle basin are transients that occur only dur-
ing migration (Appendix 3.E).An additional six
species nest in alpine tundra habitats that will be
little affected by the Susitna development.The six
species that will be most affected (semipalmated
plover,common snipe,spotted sandpiper,solitary
sandpiper,and greater yellowlegs)nest on alluvial
bars along the river edge or in lower elevation wood-
lands and meadows.No shorebirds overwinter in the
Su sitna region.
E-3-382
-i
-
:~
r
-
(ii )
Five species of larids occurred in the middle basin
in 1980 and 1981 (Appendix 3.E)(Kessel et al.
1982a).Two are confirmed breeders in the area:mew
gull and Bonaparte 1 s gull.Mew gulls were the only
common larid species in the middle basin (Kessel et
al.1982a),breeding around 1 akes and rivers.Arctic
terns and long-tailed j aeg ers were fai r ly common and
undoubtedly bred in the area (Kessel et al.1982a).
Herring gUlls were uncommon summer visitors (Kessel
et al.1982a).
Seven species of shorebirds were seen along the lower
Susitna River during a June ground survey in 1982 by
Kessel et al.(1982b)(Appendix 3.F).Spotted sand-
pipers were common breeders along shores of the main
river as well as along its sloughs and feeder creeks;
solitary sandpipers were also fairly common along the
river.Sernipalmated plovers were uncommon breeders
on alluvia,and greater yellowlegs were uncommon
probable breeders along the river.Winnowing common
snipe were recorded at numerous locations.Only one
migrant whirnbrel was observed on an alluvial island
below Tal keetna,and tl'tQ female northern phal aropes
were also seen on the river.
Six species of 1 arids were recorded in the spring
1982 survey downstrean from Talkeetna (Kessel et al.
1982b).Herring gulls were most common with at least
7 breed-ing colonies in the lower basin;the largest
colony containing approximately 1300 birds (Kessel et
al.1982b).Arctic terns and mew gulls were fairly
common breeders on river bars in isolated pairs and
small groups.Bonaparte l s gulls were fairly common
and probable nesters in spruce woodl and s adj acent to
the river.Parasitic jaegers and bl ack-legged kitti-
wakes were al so recorded in the lower reaches of the
river.Neither species breeds in the area (parasitic
j aegers breed in northv.est and northern coastal
Alaska,and the nearest black-legged kittiwake breed-
ing colony is located at Chisik Isl and in Lower Cook
In 1et)•
Grouse and Ptarmigan
Spruce grouse are year-round residents of mixed and
coniferous forests in the middle Susitna Basin.
Their status was given as fairly common by Kessel et
a 1.(1982a)WlO reported a max imum densi ty of 1.0
territor ies/10 h a in wh ite spr uce-paper bi rch forest
in 1981 (Table E.3.136).Ruffed grouse were reported
as a rare v is itant by Kessel et al (1982a).Wi llow,
rock,and white-tailed ptarmigan were all recorded as
E-3-383
4.2 -Baseline Description
breeders in the middle basin.Willow ptarmigan were
common in low shrub thickets and attained a maxil1llm
breeding density of 0.5 territories/lO ha in
dwarf-low birch shrub (Table E.3.136)(Kessel et ale
1982a).Rock ptarmigan are also common in dwarf and
low shrub at high elevations and in blockfields and
also attained maxil1llm breeding densities in dwarf-low
birch shrub (Table E.3.136)(Kessel et ale 1982a).
White-tailed ptarmigan were uncommon in dwarf shrub
mat and blockfields,and are found at generally
higher elevations than other ptarmigan,although
attitudinal ranges may overlap considerably with rock
ptarmigan (Kessel et ale 1982a).
Grouse and ptarmigan were not recorded along the
lower Su sitna Ri ver (Kessel et ale 1982b).However,
spruce grouse are 1 ikely residents of adjacent forest
habitats,and a few willow ptarmigan may migrate to
riparian habitats in some winters.
(iv)Woodpeckers and Passerines
In terms of numbers,woodpeckers and passeri nes com-
prise by far the greatest proportion of the birds in-
habit ing the Illi ddl e Su sitna Basi n.Fi fty-seven spe-
cies have been recorded,and nine (possibly 10)of
these are year-round residents (Appendix 3.E)All of
the woodpeckers and a large proportion of the passer-
ines are forest species,but passerines are found in
all vegetated habitats,from closed forest through
shrublands to alpine tundra.Breeding densities in
1981 and 1982 of these terrestrial species are given
in Tables E.3.136 and E.3.137,and are discussed in
more detail below.
The four species of swallow and the dipper are close-
ly associate with aquatic habitats,and they were not
adequately represented in censuses of terrestrial
habitats.Bank swallows .and cl iff swallows nest
colonially,the former in cutbanks and the latter in
areas of cliffs and in abandoned cabins.Tree swal-
lows and violet-green swallows are not colonial and
nest in a variety of habitats.Swallows capture food
while flying over open expanses and often over lakes
and rivers,if they are present.The dipper is a
bird of clear,fast flowing streams.It forages
year-round in shallow sections of streams and hests
along streambanks and under bridges.Dippers are
unCOJ1111on in the middle basin,but a few birds occur
in each of the major creeks that drain into the
Susitna River as well as along the middle and upper
Susitna itself (8.Kessel 1982 pers.comm.).
E-3-384
4.2 -Baseline Description
-
-
-
'~
-
(v)
Thirty-nine species of woodpeckers and passerines
were recorded along the lower Susitna River during
the spring surveys.Six (possibly seven)are year-
round residents (Appendix 3.F).Relative abundance
of some species are discussed below.
Middle Basin Bird Communities
Breeding populations of terrestrial birds in the mid-
dle basin were studied in 1981 (Kessel et al.1982a)
and in 1982 (Kessel,unpublished tables)by means of
plot censuses.The number of territories of each
s peci es on the censu s plots in the two years is shown
in Table E.3.136 and E.3.137.Breeding bird densi-
ties in 1981 and 1982 are compared in Table E.3.138.
Table E.3.139 lists the avian habitats (as described
by Kessel 1979)represented in the 10 ha censu s plots
and their approximate equivalents in Viereck and
Dyrness (1980)vegetat i on types •Kessel et a1•
(1982a)caution against the use of Viereck and
Dyrness types as avian habitat types because of:(1)
a failure to differentiate between habitats of medium
and tall shru b avi an conuru nit i es;and (2)a fa i1 u re
to restrict coniferous and deciduous forest types to
exclusively (~90 percent)coniferous or deciduous
canopy coverage.
Density of breeding birds were substantially lower
in most habitats in 1981 and 1982 (Table E.3.138).
Kessel (1983 pers.comm.)believes that the 1981
densities were probably closer to normal and that
1982 densities were abnormally low,probably the low-
est since 1964.The low 1982 densities are attri-
buted by Kessel (1983 pers.comm.)to extremely late
environmental conditions relative to spring arrival
dates of migrants in 1982.At the suggestion of the
investigators (8.Kessel 1983 pers.comm.)the 1981
data is used "in all analyses rather than a simple
average of the 2 years.
Generally,the forest and woodland habitats supported
higher densities of birds than the shrub comnunities.
Highest densities found in forests were at a cotton-
wood forest plot near Sherman,which su pported 1.7
bird territories/acre (60.9/lD ha).The lowest den-
sities in forest habitats were in the white spruce
forest plot at the mouth of Kosina Creek (0.6 terri-
tori es/acre [15.7 territori es/10 haJ).Of the shru b
habitats,low-medium willow shrub had the highest
E-3-385
4.2 -Baseline Description
densities (1.8 territories/acre [45.4 territories/10
haJ)and alpine tundra the lowest (0.2 territories/
acre [4.8 territories/10 haJ).Although alpine
tundra had the lowest bird usage,these types
supported some bird species generally not found in
other habitats,such as white-tailed ptarmigan,
horned lark,wheatear,water pipit,gray-crowned rosy
finch,and snow bunting.
Bird densities in habitats of the middle basin are
sim"il ar to those in the upper Tanana Ri ver Vall ey
(Spindler and Kessel 1980).In both regions,coni-
ferous forests were low-density habitats relative to
other forest types.Deciduous and mixed forests,and
shrubby woodlands in both regions supported inter-
mediate densities,and low shrub habitat support low
densities.Such differences in occupancy levels are
a ffected by a number of factors,inc 1u ding in
Interi or Al aska,habitat structu ral compl exity and
primary productivity (Spindler and Kessel 1980).
Tall shrub habitats in interior Alaska support the
highest avian densities (Spindler and Kessel 1980).
Kessel et ale (I982a)attributed the lower densities
in their Susitna tall alder shrub study plot to
species composition of the shrub comrTllnity.They
contrasted the average to above-average productivity
(Spindler and Kessel 1980)of the willow,thinleaf
alder (Alnus tenuifolia)and balsam poplar which
domi nated the Tanana vall ey tall shrub plot with the
relatively low productivity of American green alder
(Alnus crispa)(Spindler and Kessel 1980)which domi-
nated in the middle Susitna Basin plot.
Kessel et ale (I982a)calculated Shannon-Weaver
diversity indices (HI)for each census plot (Table
E.3.138).Diversity values are sometimes used as
indicators of habitat qual ity.Values of HI ranged
from 0.91 for the dwarf-low birch shrub plot in 1982
to 2.55 in the closed balsam poplar forest plot in
1981.With the exceptions of the white spruce forest
plot in botn years and white spruce woodland in 1982,
all plots in forest habitats obtained indices )2.0.
The tall alder shrub plot diversity index values were
2.05 in 1981 and 2.02 in 1982,while values in all
other shrub and tundra habitats were all <2.0.The 3
greatest diversity values in both years were obtained
in the balsam poplar forest,white spruce-paper birch
forest,and black spruce woodland plots (Table
E.3.138).The 1982 values on these more diverse
plots were substantially lower than 1981 index
values,the result of both reduced densities and
E-3-386
-
4.2 -Baseline Description
reduced numbers of speci es.Habitats obtai ning hi gh
values of Ware characteri zed by 1arge numbers of
species and large numbers of individuals of each
species.
Each avian habitat type (as defined by Kessel 1979)
in the middle basin supports a moderately distinct
bird species association,as indicated in Table
E.3.140.
-
-
-
,....
(vi)Lower Susitna River Floodplain Bird Communities
Information on the relative abundance and habitat use
of terrestri al bi rds in the lower Su sitna Ri ver
floodplain was obtained during a ground survey con-
ducted in June 1982 by the University of Alaska
Museum (Kessel et ale 1982b).Abundance was deter-
mined by counts of singing birds in each habitat
type.Total time spent in each of 10 habitats varied
between 30 and 352 mi nutes;data are presented as
birds per 100 minutes of survey in Table E.3.141.
Generally,following ecological tenets,both
abu ndance and speci es ri chness increased
progressively from the early to late vegetation
successional stages (Table E.3.141)(Kessel et ale
1982b)•
Species composition of the early successional stages
was dominated by waterbirds,such as plovers,sand-
pipers,gulls,and terns.The only regular land bird
was the white-crowned sparrow,which was common in
medium-height shrub at the late stages of early suc-
cession (Kessel et ale 1982b).
Species composition and abundance in the tall shrub
and forest habitats of the lower Susitna River flood-
plain followed known patterns of habitat selection in
central Al aska,except in the cottonwood forests.
Several bird species normally associated with tall
shrub comrrunities (i.e.,gray-cheeked thrush,black-
poll warbl er,northern water-thrush and fox sparrow)
were found to select nesting territories within
ri pari an cottonwood forests,probably becau se these
forests have a well-developed,tall shrub understory
(Kessel et ale 1982b).
A profound effect of silt ground cover on avian abun-
dance was also noted along the lower floodplain.
Forest and tall shrub stands with a heavy grou nd
E-3-387
4.2 -Baseline Description
cover of recently deposited silt were essentially
devoid of birdlife.Earlier studies (Spindler and
Kessel 1980;Kessel et al.,unpublished data)have
suggested that there is 1 ittle preference by most
terrestrial birds for specific taxa of plant ground
cover,but apparently some kind of vegetative cover
is necessary--u ndoubtedly becau se of its rol e in
providing food resources (Kessel et al.1982b).
4.2.4 -Non-Game (Small)Mammals
Non-game (small)mammals of the project area include shrews,
voles,lemmings,red squirrels,ground squirrels,marmots,pikas,
snowshoe hares,and porcupines.Small mammals,by the nature of
their size and visibility,are not high profile species.How-
ever,they are important ecol ogi cal components of most northern
ecosystems.Small rodents have been shown to be important in
nutrient cycling;soil aeration;dispersal of seeds,mycorhizae
and spores;control of insect pests;and as the primary or
secondary prey of many carnivores (Grodzinski and Wunder 1975).
Kessel et al.'s (1982a)studies of small mammals were restricted
to an area ranging 9.3 miles (15 km)to either side of the
Susitna River,extending from the Maclaren River on the east to
near Sherman on the west (approximately 6.2 miles (10 km)south
of Gold Creek).Within this area,49 trapl ine transects were
established and operated in the falls of 1980-1982 and spring of
1981.Sites for the transects were selected to represent as
broad a spectrum as possible of the various vegetation types in
the region.Details on sampling techniques are provided in
Kessel et al.(1982a).Information on small mammals was also
obtained by opportunistic observations.
(a)Species Composition and Relative Abundance
During the study period,16 species of small mammals were
trapped and/or observed in the middle basin (Appendix 3.G)
(Kessel et al.1982a).In additi on,there was evi dence of
two other species occurring in the region:bats (two
separate sighti ngs of what were probably the 1 ittl e brown
bat)and water shrews (tracks of a small mammal between ice
openings on Watana Creek).The distribution of small mam-
mals documented in the middle basin is similar to known dis-
tributions in the literature.However,the occurrence of
arctic shrews in the study area constitutes a minor range
extension;the closest previous record was from Denal i
National Park (Murie 1962).
The one s-pring and three fall trapline surveys involved a
total of 23,061 trap nights of effort (Table E.3.142).
E-3-388
-
-
,~
4.2 -Baseline Description
Totals of 950,138,2190,and 447 small mammal specimens
were captured during the fall of 1980,spring of 1981,fall
of 1981,and fall of 1982,respectively.A total of 1977
microtine rodents (6 species)and 1748 shrews (4 species)
was captu red.Northern red-backed vol es and masked shrews
were the two most abundant species of small mammals,
constituting 74 percent of the total captures.A total of
1458 northern red-backed vol es and 1289 masked shrews was
captured during the 1980-82 studies.Other shrews captured
were arctic shrews (303 specimens),dusky shrews (146),and
pygmy shrews (10).Captures of microtines included 224
tundra voles,103 meadow voles,148 singing voles,29 brown
lemmings,and 15 northern bog lemmings (Table E.3.142).
Capture results illustrate the large pOlJ.llation fluctuations
that can be observed within and between years (Table
E.3.142).The fall 1980,spring 1981,and fall 1981
sequence demonstrates the typi cal annual cycl e of most
short-lived iJultiparous small mammals.In such species,
summer reproduction results in high pOlJ.llation levels by
fall,and winter attrition reduces the pOlJ.llation to animals
born late in the previous summer or fall.Superimposed on
this annual cycle are yearly fluctuations in abundance
demonstrated by the fall data for the 3 successive years.
The most common microtines,northern red-backed voles,
meadow voles and tundra voles,were most abundant in fall
1981,as was the most common shrew,the masked shrew.All of
these species exhibited very low fall pOlJ.llations in 1982.
Fall 1982 capture rates were low for all species except
singing voles,brown lemmings,and bog lemmings,throughout
the study peri od.Northern red-backed vol es were the most
frequently captured microtine in all periods.Masked shrews
were the most frequently captured shrew in all periods,in
spite of their dramatic .decl ine in abundance in 1982.
$i x other species of small mammal s were not trapped but were
observed in the study area by Kessel et al.(1982a):arctic
ground squirrel,hoary marmot,collared pika,red squirrel,
porcupine,and snowshoe hare.Although no quantitative
estimates of abundance were obtained for these species,
limited information on distribution was collected and is
reported below from Kessel et al.(1982a).
The arctic ground squirrel is a common and ecologically
important mammal of the region.The 1 argest numbers were
observed on the drier slopes,knolls,and ridges above tree-
line;only small numbers were observed at lower elevations.
General observations indicate that the Susitna study area
supports a relatively high and stable popjlation of ground
E-3-389
4.2 -Baseline Description
squirrels,probably comparable to densities reported else-
where in the state (Kessel et ale 1982a).For exampl e,oj n
the Talkeetna Mountains to the south,Hock and Cottini
(1966)removed 27 squirrels in one day from 0.12/acres
(0.05 ha)(22 squirrels/acre,54/ha)with little apparent
decrease in numbers;the sqUirrel pOJl,llation in this area
remained high throughout 4 years of study.In the eastern
Brooks Range.Bee and Hall (1956)counted 175 ground
squirrels along a 0.62 miles (1-km)ridge.and 70 squirrels
on approximately 3.7 acres (1.5 ha)of hillside (nearly 19
squirrels/acre,47/ha).
Hoary marmots were locally common residents of the alpine
zone.Scattered colonies were found above treeline.None
were seen within the proposed impoundment areas.Collared
pika is another locally common alpine species,found on
talus slopes at higher elevations.No pikas were seen below
treeline.Densities of pikas in Denali National Park during
1962 varied from 2/acre (5/ha)in large rock s1 ides,to 10
acre (25 ha)on small.i sol ated rock pi 1es (Broadbooks
1965).
Red squirrels,porcupines,and snowshoe hares were generally
confined to the forested areas of the basin.Red squirrels
were present in coniferous forests throughout the area,but
were most numerous in the mature spruce stands that occur
along the larger creeks such as Watana and Tsusena Creeks.
Porcupines are uncommon in the study area;a few individuals
were sighted during the summer of 1980,and 3 to 4 sets of
tracks were seen during the winter of 1980.
Snowshoe hares,a major source of food for predators over
much of central Al aska,were generally restricted to areas
east of Watana Creek.Localized "poc kets ll occurred
primarily in the vicinities of Jay Creek,Goose Creek,and
the lower Oshetna River.Snowshoe hare populations undergo
8-to 12-year cycles of abundance (Keith and Windberg 1978);
peak densities may be as high as 15.6 hares/acre (38.6/ha)
whereas densities may drop to as low as 0.05 hares/acre
(O.12/ha)during pop.llation lows (Green and Evans 1940).
Long-term information in overall hare abundance,provided by
several local residents.indicated that the recent low
number of hares is a chronic situation and not just a low
phase of the population cycle.
(b)Habitat Use
The following analysis of habitat use draws heavily from
Kessel et ale (1982a).
E-3-390
4.2 -Baseline Description
,....
"""
,~
-
(i)Shrews and Voles
Forty-two trapping sites were organized by Kessel et
ale (1982a)into floristically similar groups using a
cluster analysis of frequency counts of 81 plant taxa·
from the vicinity of the sample sites (Figure
E.3.107).The clustered subgroups roughly correspond
to the following vegetation types from Viereck and
Dyrness (1980):sedge-grass and shrub tundra,sedge~
grass and low willow shrub,herbaceous-mixed low
shrub meadow,open white spruce forest,woodl and
spruce,black spruce bog (some low birch shrub sites
were "included in this group),paper birch-white
spruce forest,cottonwood forest,tall alder shrub,
and tall grass meadow.The number of captures of
each small mammal species relative to these vegeta-
tion types is shown "in Figure E.3.108.
Shrews and red-backed voles in the middle basin dis-
pl ayed a rel atively broad and uniform di stri but i on
pattern across habitats (Figure E.3.108).Masked
shrews,the numerically dominant shrew species,
occurred at all trapping sites.They were most
numerous in deciduous forest (particularly cotton-
wood),grassland,and tall shrub sites.Arctic
shrews occurred at 29 trapl ine sites,with peaks of
abundance on the drier,nonforested sites,particu-
larly grassland (at low elevations)and low shrub
(above treel ine).Dusky shrews were thinly distri-
buted across the vegetation types of .the study area.
Although dusky shrews were captured at 23 sites,no
particular preferences were apparent;however,none
were captured in the wettest sites.The capture of
three pygmy shrews in cottonwood forest,one in white
spruce forest,and one ·in grassland during fall 1981
and the capture of five specimens in open spruce
forest and one in cottonwood forest during fall 1980
suggest a restriction of this species to forest
habitats.Northern red-backed vol es,the domi nant
microtine of the region,occurred on all but five
trapl ine sites.Northern red-backed voles were
moderately to very abundant in most forest and shrub
types.The greatest numbers were recorded in open
and woodl and spruce and cottonwood forest sites.In
contrast,herbaceous meadows,particularly wet
meadows and paper birch forest,supported low numbers
of this species.
In contrast to the more general habitat occu pancy
patterns of most shrews and red-backed vol es,the 3
E-3-391
4.2 -Baseline Description
Microtus species displ ayed stronger habitat specifi-
city,as evidenced by their general restriction to
open,nonforested sites (Figure E.3.108).Singing
voles were captured on only 10 trap1 ine transects.
They were most abu ndant in open,low wi 11 ow-bi rch
shrub on relatively dry soils but were also found in
herbaceous tundra and mat and cushion tundra above
treeline.Tundra voles and meadow voles occurred
primari 1y in sedge and grass-forb meadows and bogs.
Tu ndra vol es were captu red on 22 sites (primarily
grass-forb,.but al so sedge-grass),compared to 10
sites for meadow vol es (primarily wet sedge-grass).
Small numbers of brown 1 el1llJi ngs were captu red on 11
sites at or above treeline,usually in wet herbaceous
and low shrub situations.Two bog lemmings were
taken at lower elevations in mesic sedge-grass/low
shrub meadow,one in grass meadow and one near a
seepage in white spruce forest.
To summarize the differences in habitat use among the
various species of small mammals,a standardized
habitat niche breadth measure was calculated for each
species captured dur"ing fall 1981 (Table E.3.143).
The ubiquitous masked shrews and red-backed voles had
the broadest habitat niche breadth,followed closely
by dusky shrews and arctic shrews.Microtus species,
particularly singing voles,had the narrowest habitat
niche breadths,along with the rare or uncOl1llJon pygmy
shrews,bog lemmings,and brown lemmings.
Small mammal community structures,especially as they
relate to species dominance and habitat breadth,are
highly correlated with pOp.llation levels and species
interactions.Because most northern microtine pOp..l-
lations undergo extreme fluctuations in density
(Krebs and Myers 1974),strict ecological boundaries
are difficult to delineate.A small mammal pOPJla-
tion sampled during the peak phase of a pOp.llation
cycl e may occu py a greater range of habitats than
during a pop.dation low.Interspecific competition
for space may a'l so vary with density.For exampl e,
Kessel et al.(1982a)found that open herbaceous-
dominant habitats left vacant by declining Microtus
pOp..l1ations were quickly colonized and dominated by
the northern red-backed vole,suggesting that
Microtus species were able to exclude northern red-
backed voles from some habitats.
E-3-392
r .
4.2 -Baseline Description
Northern bog 1emmi ngs and brown 1emmi ngs were
uncommon members of the small mammal cOll1ll1Jnity in the
Susitna Basin.Bog lemmings are generally uncommon
throughout their range,and little is known of their
ecological requirements (Banfield 1974,West 1979,
MacDonald 1980).In other areas of the state,small
numbers have been taken primari 1y in shrub bogs and
marshes (Osgood 1900,Dice 1921,West 1979,MacDonald
1980)--not un1 ike the few sites where they occurred
during this study.Their diet is apparently restric-
ted to sedges,grasses,some forbs (Cowan and Guiguet
1956),and mosses (West 1979).
(i i)
Although the high country of the middle basin has an
apparent abundance of suitable brown lemming habitat,
only small,scattered numbers were captu red du ri ng
the 1980-81 study.However,they have been found in
fai r1y 1arge numbers in other montane areas of cen-
tral Alaska (R.L.Rausch,Personal cOffilTlJnication
cited by Kessel et a1.1982a).The low numbers in
the Susitna area may be caused by a failure to sample
the right habitats,or,more likely,to sampling
during a period of low pOllJ1ation levels.Brown
lemmings are usually associated with wet sedge-grass
tundra above tree1 ine,but also are found locally at
lower elevations in spruce bogs and wet meadows
(Buckley and Libby 1957 and Banfield 1974).This
species is almost completely dependent on a diet of
sedges and grasses (Guthrie 1968),although mosses
may be important at times (West 1979).
Other Speci es
Arctic ground squirrels inhabit herbaceous tundra and
open shrub habitats above tree1 ine (Kessel et a1.
1982a).At lower elevations they also colonize
riverbanks,1akeshores,morai nes,eskers,road si d-
ings,and other disturbed sites with subc1imax vege-
tation (Guthrie 1968,Banfield 1974,Kessel et a1.
1982a).Kessel et a1.'s (1982a)observations corrob-
orate Bee and Ha11·s (1956)conclusion for the Brooks
Range that the optimum conditions for ground squirrel
colonies are:
Loose permafrost-free soils on well-drained
slopes;
-Vantage points from which the surrounding terrain
can be observed;and
-Bare soil surrounded by vegetation in an early
xerosere stage of succession.
E-3-393
4.2 -Baseline Description
Carl (1962)found that ground squirrels avoided sites
where tall vegetation (greater than 8 inches [>20
cm])impaired vision.The effects of squirrel acti-
vity--e.g.,burrowing,mound building,feeding,feces
deposition--within areas of established colonies tend
to maintain vegetation at an early successional stage
(Carl 1962 and Youngman 1975).
During the snow-free months,ground squirrels provide
an abundant,reliable food source for a number of
mammal ian and avian predators (Carl 1962,Murie 1962,
Bente 1981,Olendorff 1976).At High Lake in 1981
the first ground squirrel emerged from hibernation
the third week of April;the latest date in 1981 on
whi ch grou nd squ i rrel s were seen was October 4 (E.
Powell,Personal communication cited by Kessel et ale
1982a).These emergence and entrance dates are
essentially the same as those reported by Hock (1960)
and Hock and Cottini (1966)in the TaHeetna Moun-
tains near Anchorage,and by Carl (1962)at Ogotoruk
Creek,northwestern Alaska.
Hoary marmots and pi kas are generally restri cted to
tundra/talus habitats at high elevations (Hoffman et
a 1.1979 and Kessel et a 1.1982a).Both a re ecotone
species:their homes and shelters are in one habitat
(rocks of vari ou s si ze and shape)and thei r food in
another (herbaceous tundra types)(Broadbooks 1965).
Hock and Cottini (1966)suggested that a portion of
their marmot population underwent seasonal shifts in
altitude,moving down from-high rocky slopes in fall
to sites having better conditions for winter denning
and having an available food supply in early spring.
An opposite seasonal movement apparently occu rs in
some Montana hoary marmot col oni es (Barash 1974).
The only suggestion of fall movement in the mi ddl e
basin was the observation of several marmot trail s
and a si ngl e marmot traversi ng the 3500-foot-hi gh
(l067-m-high valley near Swimming Bear Lake (WB 150)
in about 3 inches (8 cm)of snow on October 10,1980
(T.Hobgood,Personal communication cited by Kessel
et al.1982a).Marmots hibernate longer than ground
squirrels;in the Talkeetna Mountains near Anchorage,
marmots emerge from hibernation during the first
third of May and begin entering hibernacula in early
September (Hock and Cottini 1966).Pikas are active
throughout the year (Sheldon 1930,Broadbooks 1965,
Hock and Cott in i 1966)and store 1 arge qu ant it i es of
dried plant material in late summer for use during
the winter months.
E-3-394
..-
!
r-
i
....
4.2 -Baseline Description
The arboreal red squirrel occupies a variety of
forest habitats,but prefers mature coniferous forest
(Cowan and Guiguet 1956).White spruce forest is
generally considered the optimal habitat in interior
Alaska (Nodler 1973).Red squirrels feed primarily
on the seeds of spruce,particularly white spruce,
but supplement their diet with fungi,fruits,and
even the buds of spruce and aspen (Smith 1967 and
Nodler 1973).They store large quantities of spruce
cones and mushrooms in middens for winter use (Murie
1927 and Streubel 1968).Buskirk (Personal comlTUni-
cat i on cited by Kessel et al.1982a)noted that red
squirrel middens in the middle basin in fall 1981
a ppeared to be composed only of mu shrooms and spruce
buds.A massive cone crop failure caused by an area-
wide epidemic of white spruce needle rust (Chrysomyxa
ledicola)during 1980(J.H.McBeath,Personal comllll-
nication cited by Kessel et ale 1982a)may explain
why squirrels were storing such low-quality food as
spruce buds (Smith 1967).Smith (1967)reported a
67-percent drop in a red squirrel pOp..llation follow-
i ng the second year of a two-year cone crop failu re
in white spruce forest and suggested that the
squirrels had emigrated into surrounding black spruce
stands.Repeated cone crop failu res could have
similar effects on red squirrels in the middle basin
(Kessel et ale 1982a).
In interior Alaska,Wolff (1977)found that snowshoe
hare habitat preference depended on po p..I 1at i on den-
sity;during pOp..llation lows,hares were restricted
to dense black spruce forest and willow-alder
thickets,but during highs they used a wider variety
of vegetation types,including recently burned areas
with mi nimal cover.He concluded that a patchy
environment of recently burned sites with inclusions
of unbu rned spruce was the preferred hare habitat.
The chronic scarcity of snowshoe hares in the middle
basin is probably related to a scarcity of suitable
habitat (Kessel et ale 1982a).Recent bu rns and
riparian shrub thickets are noticeably absent from
this area (Kessel et ale 1982a).
E-3-395
4.3 Impacts
Five classes of impacts to terrestrial vertebrates are anticipated to
resul t from the Sus itna Hydroe1 ectri c Project:(1)permanent habitat
loss,including flooding of habitat and covering with gravel pads or
roads;(2) temporary habitat loss and habitat alteration resulting from
reclaimed and revegetated areas such as borrow areas,temporary rights
of way,transmission corridors,and from alteration of climate and
hydrology;(3)barriers,impediments,and hazards to movement;(4)
disturbance associated with project construction and operation;and (5)
increased human access not directly related to project activities.The
acceleration of secondary development in the basin is an indirect
impact which can be neither predicted nor controlled by the Alaska
Power Authority and is therefore excluded from this discussion.
Specific impact issues associated with each class of impact are
enumerated in separate tables and discussed in the following sections
for each big game and furbearer species.
Permanent loss of specific vegetation types is shown in Tables E.3.82
and E.3.83 for the Watana and Devil Canyon facilities.Approximate
time schedule and areas affected are shown in Table E.3.144 for perma-
nent habitat loss,temporary habitat loss,and habitat alteration.
Habi tats altered by the t ransmi ss ion corri dor and access roads are
described in Tables E.3.84,E.3.85,and E.3.86.Impacts resulting from
increased human access have a1 ready begun and wi 11 conti nue throughout
the life of the project.
4.3.1 -Watana Development
(a)Moose
Moose are common in the Susitna River valley and are one of
the most important wildlife species that will be affected by
the Watana project.Act iviti es associ ated wi th the con-
struction of the Watana project will affect moose mostly in
areas adjacent to and within the dam and impoundment area.
Activities associated with the filling and operational pha-
ses will affect moose in both the middle and lower Susitna
basins.The construction and operation of the Devil Canyon
dam,access routes to the development sites,and transmi s-
sion lines also will affect moose in the Sustina Basin;im-
pacts resulting from these activities are discussed in
Section 4.3.2,4.3.3 and 4.3.4.Although the Watana project
may benefit moose in some areas of the Susitna Basin,
detrimental effects of the project wi 11 1ike1y resu1 tin a
decline in the number of moose and altered distributions of
thi s speci es throughout the bas in.Because both mi gratory
and resident populations of moose utilize areas in the
immedi ate vi ci nity of the proposed impoundment area (ADF&G
1982a),impacts associ ated wi th each phase of the project
could influence moose populations in other drainages removed
from the Susitna Basin.
E-3-396
,.....
.....
....
I
.-
i
4.3 -Impacts -Watana Moose
In this discussion,impacts of the Susitna project on moose
will be assessed by estimating the extent (temporal and
spatial)to which carrying capacity for moose is reduced
within the basin,and by the effect on population regulatory
mechanisms (Figure E.3.109).The effects of developments
that reduce carrying capacity or productivity of moose popu-
lations for more than 10 years will be considered as severe
impacts.Moderate impacts may affect either a large propor-
tion of the moose population for a short period (less than
5 years)or a smaller proportion of the population for long
periods.Minor impacts will include very short term (less
than 1 year)effects.A summary of anticipated and hypo-
thesized impacts to moose appears in Table E.3.145.
The di rect impacts that wi 11 niostseverely affect moose pop-
ulations in the middle Susitna Basin are,in order of de-
creasi ng severity:permanent loss of habitat,blockage of
seasonal migration routes,disturbance by machines and
humans,hazards associated with the drawdown zone,and
alteration of habitat.Moose in the lower basin will be
affected mostly by alteration of habitat.The major indi-
rect ~mpact of the Watana development will be the provision
of access to aprevi ous1y remote area and a substantial
increase in hunti ng pressure wi th subsequent increases in
moos e mo rta 1 ity.
ADF&G {1982a)estimated that about 2400 moose wou1 d have
home ranges that overlap a 5-mile (8-km)zone surrounding
the impoundment area.The di stance of 5 mil es (8 km)was
derived by AOF&G (1982a)as 1/3 of the average moose home
range 1 ength and assumed that moose withi n thi s di stance
would experience severe impacts.This estimate of 2400
moose was based on 162 radio-collared moose from an esti-
mated regional population of 4500 (total estimate for the
upper and middle Susitna basins).This estimate (2400 moose
severely affected)is biased by nonrandom sampling and is
undoubtedly high (see ADF&G 1982a for a discussion).How-
ever,it does provide a rough estimate of the number of
moose that may be affected by the project in the mi dd1 e
basin without mitigation.The winter carrying capacity of
the impoundment zone,and areas lost to adjacent project
facilities was estimated to be 300 resident moose for 180
days (see Section 4.2.1[a]).This value is being refined to
account for movements of moose into and out of the area,and
to better estimate moose food requirements using simulation
modeling of moose bioenergetics.
The eventual fate of the moose having home ranges that over-
1ap the 5 mil es (8-km)zone around the Watana and Devil
Canyon projects is unknown;some would successfully disperse
to other parts of the Susitna basin or to adjacent drain-
ages;some would adapt to disturbances and remain in the
immedi ate vi ci nity of the impoundment until fill i ng;and
£-3-397
4.3 -Impacts -Watana Moose
some would die as an indirect or direct result of the devel-
opment.Ongoi ng studi es wi 11 greatly refi ne thi s assess-
ment.
(i)Construction
Const ructi on of the Watana dam wi 11 invol ve intense
construction activities at the actual damsite,
estab 1i shment of tempora ry camps and a permanent
towns i te,removal of forest cover inmost parts of
the impoundment,and the excavation and transporta-
tion of borrow material.The major impacts on moose
during construction will be habitat loss or altera-
tion,disturbance.interference with seasonal move-
ments.and mortality associated with construction
activities and hunting.
-Habitat Loss
Clearing of the impoundment area,townsite~local
transportati on corri dors.and operati ona 1 areas
will result in the permanent loss of some high
quality habitat for moose in the middle Susitna
Basin.(High qual ity habitats are those areas
supporting relatively high browse production and
having snow depths less than the regional average,
are~s where spring snowmelt occurs earliest,and/or
aredS used for calving.)Campsites,borrow pits,
and construction access roads will temporarily ali-
enate smaller areas of habitat from moose use
(Tables E.3.143 and 144).There is no question
that moose will be affected by this loss of
habitat:browse availability will be reduced;
winter range.calving areas,and breeding areas
will be lost;movements may be altered as a result
of behavioral or physical barriers;animals will be
more vulnerable to predation and hunting (as a
resul t of the loss of cover);and repeated human
and mechanical disturbances may preclude use of
some areas by moose.Accidental fires may also
temporarily eliminate moose habitat,although in
the long term would provide additional areas of
high quality browse to moose.
Clearing of the impoundment area will remove a wide
range of riparian,deciduous forest,coniferous
forest.and muskeg communities which are important
to moose during all or part of the year.Although
moose may feed on the 1eaves of fell ed deci duous
trees and some areas may develop sparse succes-
sional growth prior to flooding,inundation will
E-3-398
,....,
,..,.
....
....
....
....
4.3 -Impacts -Watana Moose
eventually permanently destroy these habitats.The
distribution and occurrence of major plant communi~
ties in the Watana watershed are discussed in
Section 3.2.1.The regional availability of forest
cover types and thei r seasonal use by moose are
shown in Table E.3.146 •
•Winter Use
There is a general consensus that moose popul a-
tions in North America are ultimately limited by
the availability and quality of winter range
(Coady 1982).High quality winter range of moose
is characterized by (1)abundant trees and shrubs
that are most preferred by moose as winter
browse;(2)consistently low snow depths in rela-
tion to surrounding areas,and (3)good inter-
spersion of young seral growth (for foraging)and
older aged forest stands (for cover)(LeResche et
al.1974,Peek 1974).The nutritional quality of
browse (e.g.,amounts of crude protein,fats,and
carbohydrates;digestibility;total calories)
also is important in determining the quality of
wi nter range (01 demeyer 1974).Other factors
such as predation,hunting mortal ity,disease,
and weather may reduce moose popul ati ons below
the carryi ng capacity of the range (Fi gure
E.3.109).
Although the quality and quantity of winter range
are likely the limiting determinant for carrying
capacity of moose,they are critical to moose
survival only during severe winters.Winter
severity,parti cul arly snow depth,strongly
i nfl uences the use of wi nter browse by moose
(Coady 1974,LeResche et al.1974).During mild
winters,when snow depths are low throughout much
of the range,few moose may utilize critical
winter ranges.During severe winters,however,
deep snows may force hi gh numbers of moose to
overwinter in limited areas.The limiting effect
of critical winter range may thus be evident only
during periods of severe winter conditions •
Although not observed during current moose
studi es in the mi ddl e Susitna Basi n (ADF&G
1982a),earlier studies of moose in the basin
(USFWSF 1975,Ballard and Taylor 1980)suggest
that during severe wi nters wi th heavy snowfall,
moose move from upland shrublands to mixed spruce
deciduous woodlands at lower elevations.The
E-3-399
4.3 -Impacts -Watana Moose
Watana impoundment area includes several large
areas of river valley bottomland that are proba-
bly critical to survival of some moose during
severe winters.Mild winters with limited snow
cover during 1980 and 1981 are thought to have
resulted in the use of upland areas by moose in
the Susitna Basi nand thei r absence from lower
elevation sites.A census of the Watana impound-
ment on March 25,1982 (a time when most moose
that used the impoundment area in that year would
be found there)determi ned that 260 moose were
present in the Watana impoundment area (ADF&G
unpublished data).
Because low elevation riparian shrub,deciduous
forest,coniferous forest,and muskeg habitats
will not be available in areas adjacent to the
impoundment,the removal of these habitats by
initial clearing activities and later flooding
will deprive moose of a large area of high quali-
ty winter range.Assuming that bottomland browse
resources throughout the middle Susitna Basin are
fully utilized by moose in severe winters,clear-
i ng and fl oodi ng of the impoundment wi 11 force
moose to depend on and likely over-utilize the
remaining winter range.Moose which never use
the impoundment area wi 11 also be affected by
over-utilization of these adjacent areas.In-
creased mortality would be expected caused by
starvation and increased predation,whereas
natal ity may decrease because of the poor
physical condition of moose •
•Spri ng Use
During recent moose studies (ADF&G 1982a),many
(no numbers available)of the radio-tagged ani-
mals moved to lower elevation habitats adjacent
to the Susitna River during late spring.It is
believed that these movements are related to the
earlier snowmelt and emergence of new plant
growth in low elevation sites (ADF&G 1982a).
Because moose typi cally have a negative energy
balance during winter and are in poor physiolo-
gical condition by late spring (Gasaway and Coady
1974),the availability of new plant growth may
be critical to survival.During the spring,
parturient cow moose commonly use low elevation
sites along the middle Susitna valley,presumably
to calve (no numbers given in ADF&G 1982a).The
E-3-400
-
4.3 -Impacts -Watana Moose
availability of new plant growth and suitable
shrub cover in these low elevation sites .is
thought to be impo rtant to the survi va 1 of both
the cow and her calf.Bull moose and cow moose
without calves also utilize the low elevation
habitats during the spring (ADF&G 1982a).
Cl eari ng and fl oodi ng of bottoml and areas waul d
reduce availability of lower elevation sites
where spring snowmelt and plant emergence appears
to be more rapid.Because micro-climatic
changes resul t i ng from the impoundment are sug-
gested to delay spring green-up by 5-15 days
(McKendrick et al.1982)and because habitats
which will remain available around the impound-.
ment area are at higher elevations,moose may be
deprived of a large area of early spring habitat.
This impact would be most severe following
winters with deep snowfalls when moose may be
highly dependent on the availability of these
spring foraging areas.
ADF&G (1982a)suggest that concentrations of
calving moose occur in the impoundment area and
that these may represent traditional calving
sites (no unequivocal data are provided,see
ADF&G 1982a).Al though it has not been shown
that moose use traditi anal cal vi ng areas (as do
several other species of ungulates),studies by
Markgren (1969)and Stringham (1974)suggest that
a calvi ng location may be used repeatedly by an
individual cow.Predation moose calves by brown
bears is a major mortality factor of moose during
the spring and summer (Ballard et al.1980),and
di spl acement of parturi ent cow moose from thei r
habitual calving areas by clearing activity may
increase the vul nerabil ity of thei r cal ves to
predation •
•Summer and Fall Use
Because most moose in the middle Susitna Basin
commonly move to upland shrub habitats during
summer and fall,loss of bottomland communities
will not have serious effects on summer and fall
habitat use.However,some sedentary (or non-
migratory)moose remain in the valley bottoms
throughout the year·and these i ndivi dual s waul d
be displaced from their summer and fall range.
E-3-401
4.3 -Impacts -Watana Moose
-Di sturbance
During construction of the Watana dam and clearing
of the impoundment area,human and mechani cal di s-
turbance will likely limit the use of several
development areas by moose and could result in
alterations in feeding behavior.Because undis-
turbed ungulates spend much of their active period
searching for and consuming food (Hudson 1977),
disruption of daily activities can reduce feeding
acti vity to the poi nt where an i nd i vi dua 1 deri ves
1 ess energy from the resources consumed than it
expends (Geist 1975).Ungulate energy balances are
most del icate during the winter (Dorrance et ale
1975,Moen 1976).Therefore,disturbances are
likely to have the most severe impacts on ungulates
duri ng thi s season.An assessment of the effects
of di sturbances on the energy balance of moose in
the middle Susitna Basin and subsequent effects on
productivity is not possible on the basis of
current information,but will become feasible using
the modeling approach being developed (see Section
4.3.1(a)(iii).
Although repeated human and mechanical disturbances
could result in an alteration of activity budgets
with consequent impacts on growth,survival,and
production,a more serious immediate impact is the
alienation of some portions of the range as a
result of possible avoidance of human activity
areas.Prolonged avoidance would result in an
effective loss of habitat,and animals may concen-
trate in limited areas of prime range or subsist on
marginal range.Either scenario could result in
over-browsing and a reduction in carrying capacity
with eventual population declines (Sopuck et ala
1979).
Moose appear to be more tol erant of disturbances
than most ungulates (Tracy 1977),particularly if
disturbances are predictable,neutral stimul i such
as moving vehicles (Kucera 1976,Schultz and Bailey
1978).Cow-calf pai rs generally respond to dis-
turbance more strongly than bulls and cows without
calves (Tracy 1977).If moose are not directly
approached by humans or machi nes,they appear to
tolerate even moderate and high activity levels.
For example.repeated aerial surveys of moose in
the vicinity of the Revelstoke Hydroeletric Project
E-3-402
'"'"'
'"'"
4.3 -Impacts -Watana Moose
in British Columbia over a five-year period that
spanned preconstruction and construction phases
indicated that moose numbers had not changed
despite frequent blasting and heavy industrial
activity (R.Bonar 1982 Personal Communication).
Observations of moose,including cows and calves,
in close proximity to active oil sands extraction
plants in northern Alberta despite frequent
mechanical disturbances and blasting,support this
observation (J.Green 1982 Personal Communication).
However,toleration of such activities by moose
appears to occur only in the absence of high levels
of human harassment and hunti ng.Moose can be
expected to avoid human activity areas if harass-
ment and/or hunting commonly occur.
Assuming that the Watana dam construction site and
associated facilities are restricted to as small an
area as possi b1 e and that hunti ng from project
facilities and harassment is prohibited,moose
would probably continue to utilize forested areas
near these sites.(Hunting has been prohibited
within a IO-mi1e corridor containing the
Trans-Alaska pipeline and can be regulated by the
Alaska Board of Game.Harassment is prohibited by
state law and can be minimized by adequate enforce-
ment.)If hunting from project facilities and
access routes is permitted,moose will avoid the
major activity centers,resulting in an additional
loss of habitat beyond that associ ated wi th only
the impoundment and discrete construction areas.
Because the cl eari ng of the impoundment wi 11 i n-
volve noisy and unpredictable disturbances,moose
will probably avoid the areas of active clearing.
This and additional loss of habitat resulting from
a lack of cover in cleared sites will gradually
increase the intensity of use of browse in areas
outside the impoundment area during the
three-to-four-year c1 eari ng program.The concen-
tration of moose in these areas will increase
i ntraspecifi c competiti on for food and space.If
the populations in these adjacent areas are at or
near carryi ng capacity,mor.ta1 ity of moose as a
result of starvation and predation may increase,
natal ity may decrease,and carryi ng capacity and
population productivity will gradually decline.
Aircraft enroute to or from the Watana airstrip may
cause mi nor di sturbances to moose.In general,
E-3-403
4.3 -Impacts -Watana Moose
most aircraft are expected to maintain high alti-
tudes except during landing and take-off,and will
not be a major disturbance stimulus.Frequent,
low-altitude flights by fixed-wing aircraft or
helicopters may elicit panic responses in moose.
Because the intensity of reactions to ai rcraft by
ungulates is influenced by such factors as the time
of year;distance of the aircraft from the animals;
group size;sex and age composition;type of air-
craft;activity of the animals;and the type of
terrain (Sopuck et al.1979),it is difficult to
general ize potential impacts on moose of repeated
ai rcraft di sturbance.The use of wooded areas on
or in the immediate vicinity of several interna-
tional ai rportsin Canada suggests that if moose
are not harassed,they will habituate even to
frequent low altitude overflights (Green 1981).
-Interference With Seasonal Movements
Clearing of the impoundment area will not physical-
ly obstruct ri ver crossings or seasonal movements
but may interfere with these movements through
avoidance of active clearing operations or the ex-
pansive clear-cut areas.Increased visual exposure
to predators and hunters may i nhi bit moose from
crossing these cleared areas.Several studies have
documented avoidance of large clear-cut areas by
moose (Hamilton and Drysdale 1975,Parker and
Morton 1978,Tomm 1978);in general,moose appear
reluctant to enter areas where they woul d be far
(i.e.,more than (163-218 yards)150-200 m from
forest cover.Following filling,the Watana
impoundment wi 11 const i tute a greater obstacl e to
seasonal movements of moose than did the river.A
more detailed discussion of the effects of the
Watana development on seasonal movements is
discussed below under Filling and Operation.
-Mortality
An unpredictable number of moose may be killed as a
result of collisions with vehicles or other acci-
dents associated with construction activities.
Mortality to predators may also increase if
impoundment clearing facilitates hunting by wolves.
The effect,of these mortal it i es on moose popul a-
tions is likely to be minor.The most serious
mortality factor associated with the construction
of the Watana dam wi 11 be the increase in hunt i ng
associated with the influx of people into a previ-
ously remote area.Effects of increased hunting on
moose are described more fully in Section 4.3.3(a).
E-3-404
-
.....
.....,
..."
4.3 -Impacts -Wata~a Moose
(ii)Filling and Operation
During the filling and operation phases of the watana
development,the major impacts to moose will be per-
manent loss of habitat,alteration of habitats
upstream and downstream from the damsite,blockage of
movements,di stu rbance,and increased accidents and
hunting mortality.
-Permanent Loss of Habitat
As flooding of the impoundment area proceeds,a
variety of bottomland and low elevation habitats
along the Susitna River will be permanently lost.
As discussed above for the construction phase of
the project,clearing of the impoundment area will
have already resulted in a substantial reduction of
the value of these areas to moose.By the time
these areas are flooded,few or no moose may be
utilizing these areas.However,the impoundment
will permanently alienate the area from moose use.
The consequences of the loss of these low elevation
areas have been discussed in the previous section •
As a result of the habitat loss,moose will be
forced into adjacent areas.Although it is not
possible to predict the distances moose will dis-
perse from the impoundment area,it is clear that
densities in adjacent areas will increase during
the clearing and filling of the impoundment.
Hunting guides in the vicinity of the W.A.C.
Bennett dam in northern British Co lumbi a reported
an increased harvest of moose in areas near the
impoundment for a few years following flooding (K.
Child 1982 Personal Comrrunication).Increased
moose densities could result in a decline in habi-
tat quality in adjacent areas.If overutilization
of food resources,particularly winter browse
(generally conceded to be a major 1imiting factor
in moose pOl)Jlations)occurs,increased mortality
and decreased productivity can be anticipated.
During the operation of the Watana dam,a maxilTUm
drawdown of 95 feet (29 m)will create an unvege-
tated shorel ine zone that,in the Watana Creek
area,may be over 0.67 miles (1 km)wide.The
impoundment level will be at its highest in August
and September,and will generally decline between
E-3-405
4.3 -Impacts -Watana Moose
October and August.Although a few herbs and forbs
may become established during early summer~most of
the area wi 11 remai n a bare Il1.ld slope.Fi ne mate-
rial will gradually move downslope so that much of
the upper drawdown zone will eventually be composed
of coarser materi al •Except du ri ng crossi ngs of
the reservoir~it is unlikely that moose will uti-
1 ize the drawdown area.Hazards of the drawdown
area to moose movements are discussed below.
-Alteration of Habitats
The Watana Project will result in the alteration of
plant comll1.lnities in both the upstream and down-
stream Susitna Basins (Section 3.3).These altera-
tions will affect moose use of existing habitats
and may have some effects on the long-term produc-
tivity of populations •
•Upper Susitna Basin
Based on analyses of home ranges and seasonal
movements (ADF&G 1982a)~radio-collared moose
commonly utilize lower elevation habitats in
close proximity to the future impoundments.
Vegetation in the areas immediately adjacent to
the impoundment may be altered as a result of
several mechanisms such as minor changes in
seasonal temperatures~wind direction and speed~
and ice fog preventing direct sunlight from
reaching the ground (see Section 3.3).
If the proposed reservoirs decrease either spring
daytime temperatures (Baxter and Glaude 1980)or
insolation,the spring green-up period may be
delayed.This phenomenon is complicated by the
fact that some plants use photoperiod rather than
temperature to trigger early spring growth (see
Section 3.3.1).If snow depths along the im-
poundment shoreline increase~plant green-up may
be delayed.Some parturient cow moose,as well
as male and young moose~were apparently observed
to move to lower elevation areas of the Susitna
Ri ver du ri ng the early spri ng~presumably to
utilize the early emerging vegetation (ADF&G
1982a~no actual numbers avail abl e).Assumi ng
that the timing of the spring green-up is
important to the condition of parturient cows and
E-3-406
-
-
-
4.3 -Impacts -Watana Moose
the survival of their calves,any delay in green-
up may reduce the survival of the calves.If
moose are forced to utilize higher elevation
a reas where green-u pis 1ater (i n compari son to
low elevation sites),areservoir-'mediated delay
in green-up would further aggravate problems of
nutritional stress during the spring period.
Erosion of the impoundment shore will likely
occur during the period of maxirrum fill until the
new banks become stabilized.In particular,
permafrost slumping along the south shore of the
impoundment may eliminate large areas of habitat
along the shore,although most of the unstable
areas are steep slopes of 1ittl e value as moose
habitat.Areas of successi onal vegetation,
favorabl e to moose,may develop on some of the
resulting more gently sloping areas along the
shores of the reservoir •
•Lower Susitna Basin
Changes in the flow regime will alter the avail-
ab"il ity and local distribution of important moose
habitat in the lower Susitna Basin.The extent
of vegetation changes will vary considerably
along the lower reaches of the Susitna River
because of the diluting effect of tributaries as
well as changing channel morphology (see Section
3.3.1).Differences between pre-and post-
project flow regimes wi 11 be greatest upstream
from Talkeetna;change in the frequency and dura-
t i on of flood ing,ice scou ri ng events,and
shifting of bed materials will be less noticeable
as one progresses downstream.
The alteration of moose habitat in the reach
between Watana and Talkeetna can be better pre-
dicted than for areas further downstream.Be-
tween Watan~and Devil Canyon,the river is con-
tained by bedrock outcrops and steep canyon
sides;early successional vegetation favored by
moose occurs mostly on islands and along a narrow
band adj acent to the ma in channel.The lower
summer flows and lack of ice scouring will result
in the colonization of a narrow band by new vege-
tation and the succession of some areas now
subject to vegetative recession to climax forest.
Although moose habitat will be improved for 10 -
20 years,the lack of flooding and ice scouring
E-3-407
4.3 -Impacts -Watana Moose
events wi 11 eventu ally resu 1t in t he dec rea sed
a va il abil ity of good moose habitat along thi s
river reach.
In addition.preferred moose browse may become
unavailable in winter because of blockage of
movements by open water areas.and heavy frosting
of vegetation along this open water reach.The
icing effect is likely to be heaviest within the
steep canyon as it is downstream from the Peace
Canyon dam in British Columbia (where the climate
and topography is similar)(Movold 1982 Personal
Communication).In most areas.icing is unl ikely
to reduce brouse availability.but it will
increase the energy requirements of moose which
consume large quantities of ice.
Du ri ng 0 perat ion.t he a rea in the Devi 1 Ca nyon-
Talkeetna reach supporting early successional
plant cormunities will be regulated by flow dis-
charge from Watana at freezeup (see Section
3.3.1)•Hi gher post-proj ect wi nter flows wi 11
initially cause a widening of the unvegetated
floodplain.including a decrease in the size of
i sl ands.If flows at freezeu p are kept constant
each year.little browse would be available to
moose at any time of the year.However.flows at
breaku pare vari ed to meet energy demand or a
reservoir level rule curve,the early succes-
sional stands will appear as plants colonize the
scoured areas above the winter ice stage.
Female moose in the area north of Talkeetna
appeared to move to and use riparian habitats and
river islands during the calving period (ADF&G
1982b).Islands appeared to be particularly good
calving areas.perhaps as a result of lower
numbers of predators (Stringham 1974).Stable
winter flow release will cause a decrease in the
amount of early-successional vegetation in this
reach,thereby degradi ng cal vi ng habitat.Most
river islands will decrease in size,thus provi-
ding fewer areas for calving.If any islands
become connected to the river banks,their value
as calving areas will be further decreased.
The effects of the project on the quantity and
quality of moose browse downstream from Talkeetna
will be less than those between Devil Canyon and
E-3-408
-
-..
4.3 -Impacts -Watana Moose
Talkeetna,but because the number of moose using
th~river increases as one moves downstream,smal
sma 11 effects on vegetat ion cou 1d resu 1t in re 1a-
tively greater effects on moose.In winters of
deep snowfall (such as in 1982-83),the amount of
browse available above the snow surface probably
1 imi ts the moose pOJ)ll at i on,and in these
winters,a decrease inavailability of brouse can
be translated to a proportional change in the
moose pOJ)ll ation su pported along the ri ver.In
most winters,however,the amount of riparian
vegetation does not limit the pOJ)llation (Section
4.2.1[a]),and changes in browse availabiity
would be less important.
As discussed in Section 3.3.1(a),the area colo-
nized by early-and mid-successional vegetation
will vary considerably during the license period
depend i ng on the t il11i ng of peak floods of the
various tributaries and river stage at freezeup.
Additional research is in progress to improve the
abil ity to predi ct futu re trends in the quantity
and qual ity of moose browse based on an under-
standing of bank erosion processes,the
importance of ice scouring in vegetative reces-
sion,and colonization rates on different
substrate types.
-Blockage of Movements
Studies of seasonal movements of moose in the
middle basin have identified several sites along
the river where moose crossings tended to be con-
centrated (ADF&G 1982a).Depending on the time of
year,moose attempting to cross the impou ndment
would encounter open water or uncertain ice condi-
tions.Drifted snow near the southeast end of the
impoundment could physically prevent moose from
crossing the impoundment at that location.Because
all of the recorded moose crossings of the Susitna
River du ri ng 1980-81 occu rred du ri ng May to
November,moose wi 11 most commonly encou nter open-
water conditions.In addition,these animals would
have to descend over mud flats or ice blocks within
the drawdown area.Percentage slopes of the draw-
down area in the Watana impoundment will range from
less than 5 percent to as high as 115 percent
(Hanscom and Osterkamp 1980).As a result of both
the physi cal and vi sual barri er effects of the
impoundment,it is likely that some moose movements
will be blocked by the impoundment.
E-3-409
4.3 -Impacts -Watana Moose
Moose in British Columbia apparently do not seem to
cross the open river area below dams in wi nter
(Harper 1982 Personal Cormunication).The stretch
of open river between Watana and Devil Canyon
during winter will interfere with moose crossings
during that season.
Moose in Alaska are adapted to and are dependent on
seral habitats in at least a portion of their sea-
sonal range (LeResche et ale 1974).With the
exception of riparian zones,which are seral commu-
nities with predictable locations,most
successional comrrunities are products of random
events such as forest fires,slides,or storms.To
utilize new successional areas,moose rrust maintain
some degree of fl exibil ity in thei r seasonal and
regional movement patterns.It is probable then
that surviving moose in the vicinity of the
impoundment will alter seasonal movements and cros-
sings to maximize use of the remaining browse and
forage su ppl i es.
Blockage of seasonal movements,particularly to
winter ranges or to calving areas,could severely
affect moose pOJX.Ilations if no alternative ranges
are available.Moose distributions during 1980
suggested that rel at i vely hi gh concentrations of
moose overwi ntered on both sides of the proposed
impoundment.Locations of moose during the calving
period similarly suggested that although moose were
located more often to the north of the impoundment,
animals probably calved on both sides of the
impoundment.Relocations of moose during 1981-82
suggest that,although some moose cross the Susitna
River to winter or calve,suitable habitat for
calving and wintering are available on both sides
of the vall ey.However,there is one report that
moose have been known to starve to death in a tra-
ditional foraging area,even though adequate
habitat was present nearby (W.Ballard 1982
Personal Communication).
Additional information on the availability of cri-
tical winter range and calving habitats following
flooding is being obtained to more accurately
assess the impacts of interference with seasonal
movements.
E-3-410
.....
-
.-
4.3 -Impacts -Watana Moose
-Disturbance
Mechanical and human disturbance should decline in
the impoundment and constructi on areas once the
Watana dam is operational.Public access will
continue to increase levels of disturbance,though
at a level lower than during construction.
Helicopter and boat trips to the Jay Creek mineral
lick by project personnel and recreationists would
have an insignificant effect on moose.If animals
are not directly harassed,disturbances during the
filling and operation stages,with the exception of
hunting,will at most have a slight effect on moose
distributions.
-Mortality
During the filling and operational phases of the
Watana project,hunti ng mortal ity of moose may be
much greater than current 1evel s.Constructi on
workers may hunt,and improved access wi 11 permi t
hunters to reach many more areas within the Susitna
Basin.Hunting pressure will likely increase
rapidly duri ng the fi rst fi ve to ten years of the
project,and increased harvest of moose is ex-
pected.Hunting will prevent over-brousing of
remaining range by removing displaced animals
(assuming adjacent areas would be over-utilized as
a result of moose dispersal from the impoundment
a rea)•
Mortality of moose may result from animals being
injured on ice shelves,falling through the ice
after the water 1evel has been drawn down (Harper
1982 Personal COlTImunication),or from animals
becomi ng mi red in the drawdown area.Moose have
also become trapped and drowned in floating debris
within impoundments (Child 1982 Personal Communica-
tion).Floating ice during breakup may cause
similar increases in crossing mortality.The
number of moose accidentally killed each year as a
result of the impoundment hazards,based on experi-
ence from impoundments in British Columbia (Bonar,
Harper,Childs 1982 Personal Communication)is
unlikely to exceed one percent of the moose popula-
tion occurring within five miles of the impound-
ment.However,highway and railroad kills
associated with the project may be substantial (see
Section 4.3.3[a]).
E-3-411
4.3 -Impacts -Watana Moose
The impoundment will also affect predation rates on
moose.The ratio of brown bear to moose may
increase in the early years of filling and
operation.Bears may also kill more moose to
compensate for the loss of vegetation in spring.
Thedrawdown zone and ice conditions may facilitate
hunti ng of moose by wol ves.If a severe wi nter
occurs during or just after filling,the moose
population may suffer high winter mortality,
reducing its ability to sustain high levels of
predation.These factors could allow predation to
drive the moose population to low levels,with slow
recovery because of sustained predation levels.
(iii)Quantification of Project Effects
The loss or alteration of moose habitat in the middle
basin during both winter and summer has been identi-
fied as the major impact of the project on moose.
The population-based studies conducted to date indi-
cate the magnitude of use of areas by the exi sti ng
populations during the study,but do not allow a
quantitative assessment of the potential of the
habitat to support moose under varying environmental
condi ti ons.To estimate moose carryi ng capacity in
the Susitna project area,a moose bioenergetics model
is being developed.This habitat-based assessment,
in combination with the population-based assessment
currently underway,should provide a strong basis for
impact prediction and mitigation planning.
Carrying capacity models based upon the nutrient
requi rements of the anima 1 and the capacity of the
range to supply these necessary nutrients have
recently been developed (Moen 1973,Wallmo et ale
1977,Mautz 1978).The nutritional interfaces
between the animal and range are forage sel ect ion,
ingestion,and digestion.Forage quality can be
assessed by measuri ng avail ab 1e ni trogen and energy.
Other nutritional entities are requisite to the
health of wild ungulates,but they are seldom the
limiting factor.'A simulation model of ruminant
energy and nitrogen balance developed by D.M.Swift
(1983)and Swift et al.(1981)has been adapted to
moose (Rege1in et a1.1981)Schwartz and Franzmann
1981b).This model predicts rates of daily forage
intake and changes in body weight and composition of
E-3-412
~,
,....
-
,....
4.3 -Impacts -Watana Moose
an individual moose based upon the composition and
quality of ingested forage.The basic research
necessary to adapt the model to moose was conducted
at the Moose Research Center near Soldotna,Alaska,
during the past five years.Required information to
adapt the model to moose included moose energy and
protein requirements,digestive capacity,rumen turn-
over time,rate of passage,and partitioning of
energy from gross energy intake to net energy avail-
able for production (Regelin 1982 Personal
Communication).
The model estimates dai ly energy and nitrogen re-
quirements for non-reproducing moose.Based on daily
diet digestibility and nitrogen concentration,the
model predicts total voluntary intake;rates of di-
gestion and passage;partitioning of energy and
nitrogen to mai ntenance,growth and fatteni ng;
changes in 1ean body mass and adi pose reserves;and
returns of energy and nitrogen to the ecosystem
(Swift et ale 1983).Specific information on the
range nutri ent supply must be coll ected from each
area where carrying capacity is to be predicted.The
data needs are the amount of available forage,quali-
ty of the forage,and food habits of moose.The data
are fi rst used in the rumi nant sub-model to predi ct
daily intake rates.A separate model then estimates
the potential carrying capacity of the area.The
total amount of digestible energy and crude protein
available to moose is calculated.The carrying capa-
city is determined by dividing the daily requirements
for digestible energy and crude protein into the
total amount available.Separate estimates are made,
based upon crude protein and digestible energy.
Carryi ng capacity can be expressed as the number of
moose days of use or the number of moose~and can be
predicted for summer or winter periods.
The ruminant sub-model has been adapted to moose and
produces realistic outputs;however,the model has
not been validated under field conditions.There are
currently plans to validate the model using moose
withi n four 1-mi 2 pens at the Kenai Moose Range.
Potential carrying capacity will be predicted in each
enclosure,and each will be stocked with moose at
different densities.The moose will be weighed peri-
odically to determine if the sub-model correctly pre-
dicts changes in body weight.
Specific data needed to quantify the carrying capaci-
ty of moose within the middle basin are listed below
(Regelin 1982 Personal Communication):
E-3-413
4.3 -Impacts -Watana Caribou
-Detailed vegetation maps of the Watana impoundment
area and middle basin.The areal extent of each
vegetation type must be calculated and the spatial
distribution of each type must be determined.
-Standi ng crop bi omass of moose forage wi thi n each
vegetat i on type must be determi ned through appro-
priate sampling methods.
-Food habits of moose during October,February,May,
and July need to be determined.Fresh fecal
pellets should be collected at each season and
analyzed by the microhistological technique to
determine food habits.
-Seasonal nutritional qual ity of moose forage needs
to be measured.Important forage speci es (4-6
species)should be collected during October,
February,May and July.Only pl ant parts eaten
should be collected from several locations within
the area.Samples should be ground in a Wiley mill
and analyzed for N content and in vitro digestibil-
ity.Moose rumen fluid should be utilized in the
in vitro digestion process.
Nonhabitat rel ated impacts such as increased preda-
tion or crossing mortality will also be assessed
through the use of simulation modeling.Various
levels of predation or other mortality will be input
to the model now being developed to assess the
resulting long-term effect on the population.Pre-
1 imi nary outputs from these ana lyses wi 11 be
available in 1983,but the combined effects of habi-
tat loss and alteration and various di reet mortal ity
factors will not be available until 1986.
(b)Caribou
Anticipated and hypothesized impacts to caribou are summa-
rized in Table E.3.147.Alaska's Nelchina caribou herd is
an invaluable wildlife resource and may be subject to
serious impacts as a result of the Watana project.In
particular,concerns have focused on the position of the
impoundment ina mi gratory corridor.Di rect impacts here
treated include blockage of migratory routes,hazards
associated with impoundment crossings,disturbance,and loss
of habi tat.Increased access wi 11 be a major i ndi rect
impact.
E-3-414
4.3 -Impacts -Watana Caribou
-
I"""
i
-
(i)Constructi on
Construction activities in the immediate vicinity of
the Watana dam are unlikely to greatly affect caribou
of the Nelchina herd.
The constructi on s;te will remove much 1ess than one
percent of infrequently used habitat.Although some
caribou may ;encounter and avoid areas of intensive
human activity,this should not result in any popula-
tion effects.Proposed borrow sites also cover less
than one tenth of one percent of caribou habitat and
are temporary facilities.Borrow sites A,D,and F
are more likely to be frequented by caribou than are
the other potential borrow sites.Most use of these
areas is attributable to summer use by bulls,and it
is unlikely that the cow/calf segment of the main
Nelchina herd will come close to the borrow sites
during annual movements.Although bull caribou
appear to be less sensitive to human activity and
disturbance than other portions of the herd,they may
still avoid the areas during active mining to a limi-
ted extent.As a result,the borrow sites will re-
present an inconsequenti al loss of summer bull habi-
tat.Caribou may avoid the construction camps and
permanent vill ages,but aga in these areas remove a
relatively small area of infrequently used habitat.
Aircraft traffic will increase considerably in the
middle basin as a result of the project.The degree
of response of caribou to aircraft disturbance
depends on many factors,including:aircraft type,
altitude and horizontal distance from the animals,
season,group size and composition,previous
activity,herd experience and habitat type.There is
some evidence that aircraft disturbance could result
directly in the death of young animals (DeVos 1960,
Miller and Broughton 1973).However,no unequivocal
evidence of this for wild animals is available,and
except for intentional harassment of animals byair-
craft or low-altitude flights causing groups of
animals to stampede,the main concern of aircraft
harassment is related to its energetic effects.
Caribou and other large mammals often react to a
low-flying aircraft by running.The energetic cost
of running in caribou can be 8 to 20 times the basal
metabolism (Geist 1975),and there is some evidence
that the energy costs to animal s that show no overt
response at all to disturbance are nevertheless
increased (e.g.,MacArthur et ale 1979).
E-3-415
4.3 -Impacts -Watana Caribou
Most studies have found that fixed-wing aircraft are
less disturbing than helicopters,other factors being
equal (Klein 1974,McCourt et ale 1974,Surrendi and
DeBock 1976,Fischer et ale 1977,Miller and Gunn
1979),although horizontal and vertical (altitude)
distances have not always been distinguished.Shank
(1979)general ized results of all these studi es and
suggested that response levels decreased rapidly with
increasing distance from the aircraft up to distances
of about 250 feet (80 Ill).Beyond 250 feet (80 m),
response levels decreased more slowly,and there was
great variability in the level of response at parti-
cular altitudes.The results of both Fischer et ale
(l977)and Miller and Gunn (1979)suggest that re-
sponse levels decrease with increasing horizontal
distance in a much more regular manner than the de-
crease in response with decreasing vertical distance.
From the various studies that have been conducted on
large mammals,and by extrapolating from the domestic
reindeer literature (Zhigunov 1968,Klein 1971),it
is evident that very high levels of disturbance from
1 ow-flyi ng ai rcr-aft coul d affect the producti vity of
cari bou;however,if pil ots mai ntai n an al titude of
at least 1000 feet (300 m)above sound level whenever
possible 2000 feet (600 m)agl over the calving
grounds during April-July),there is little evidence
to suggest that cari bou woul d be seri ously affected
by ai rcraft associ ated wi th project constructi on and
operation.
(ii)Filling and Operation
I
the area to be flooded by both the Watana and Devi 1
Canyon impoundments represents much less than one
percent of the Nelchina herd's range (ADF&G 1982c).
Skoog (1968)considered the middle Susitna bottomland
to be low quality grazing habitat,but noted its
importance to migrating animals at several times of
the year.The loss of caribou habitat as a result of
i nundati on wi 11,therefore,not be of major conse-
quence to the herd,and by itself should not cause
any change in herd size,productivity,or distribu-
tion patterns.
Info rmat i on collected on the movements of the
Nelchina caribou herd since 1947 indicate that the
proposed Watana impoundment woul d intersect a major
caribou migration route.This has led to concerns
that the impoundment and other project faciliti~s
might serve as barriers to caribou movements,cause a
decrease in use of portions of the range,increase
the mortal ity rate,and tend to isolate one or more
E-3-416
-
4.3 -Impacts -Watana Caribou
subherds having separate calving grounds.Many
secondary impacts,whose probabil ity would be even
more difficult to predict,would follow,incl uding
increases in pred ator po pul at ions wh ich wo ul d further
increase mortal ity,decreases in the birth rate and
in calf survival,and decreased potential carrying
capacity because of alienation from use of some por-
t ions of the range.
Ho\A,€v er,1arge movooents of car ibou across either of
the proposed impoundment areas have been reported
only once si nce 1973 (skoog 1968,ADF&G 1982c).
Hemming (1971)reported that,as the herd increased
in size between 1947 and 1962,shifts in range use
and seasonal spl itting both increased in frequency,
and the herd expanded its range.Conversely,as
n umbers decreased after 1962,the area occupied by
the herd contracted toward the traditional cal',;ing
area in the Talkeetna MJuntains.
It thus appears that there is a close rel at ionshi p
between herd size and the potential for adverse
impacts caused by the Su sitna Hyd roel ect ric Proj ect.
As the herd increases,large movooents of caribou
across the Watana impoundment and Denal i to Watana
access road will likely recur.However,major move-
mentsacross these facil it ies are not expected under
the current Nelchina caribou managooent pl an (ADF&G
1976),which incl udes a managooent guidel ine to har-
vest the annual increment after the herd reaches
20,000 adult caribou.Herd mov61lents.during the
construction phase are not likely to differ greatly
from those observed during the past five years,since
herd size is not likely to exceed 30,000 caribou
before 1990.
It is not possible to determine to what extent,if
any,portions of the historically used range would
become al ienated from regul ar use by the impoundment.
It is possible that isolated subherds with separate
calving grounds would regularly utilize those por-
tions of the range.It is also possible that no
decrease in use will be detected (although mortali-
ties related to impoundment crossing will occur).If
port ions of the range are al ienated from reg ul ar use,
the project wi 11 resul t in a decrease in the abil ity
of the range to support population levels M'lich have
occurred in the past.Although current managanent
pl ans call for maintenance of the herd at 20,000
E-3-416A
4.3 -Impacts -Watana Caribou
adults,the option to allow a substantial increase
may be foreclosed by development.Again,it is not
possible to determine the value of this hypothetical
upper 1 imit at the present time or how much it may be
reduced by the project.
Even at current herd si ze,the Watana reservoir will
interfere with the migration of caribou between por-
t ions of the herd I s range and may increase mortal ity
during migration as a resul t of hazards created by
the impoundment.Although the 1 arge movements of
caribou recorded in the past across the proposed
Watana impoundment area have not occurred in recent
years,the area is still used by many caribou as a
travel route.Nine crossings of the prop:lsed
impoundment by six radio-collared caribou were
documented during studies in 1980 and 1981,and other
caribou apparently walked along the river ice between
the Tyone and Oshetna Rivers area to Kosina Creek and
Watana Lake,where they then moved into the Talkeetna
Mountain foothills.
Crossings of the impoundment in 1980 and 1981
occ urred mostly between Apr i 1 10 and May 31,and
between August 1 and September 30 (ADF&G 1982c).
About 10 percent of the main herd crossed the river
during Q:tober 1982 (Pitcher 1982 Personal Communica-
t ion).Th e annual drawd own of the reservoi r in
winter will result in the impoundment being at its
lowest level at the time of the spring migration,in
late April and early May.At this low point,the
impoundment will average approximately 95 feet (29 m)
lower than when it is full in Oc tober.Th e grad ual
winter drav.down will result in the formation of ice
blocks grounded on the shore.Where the slopes of
the shoreline are gradual,such as along the Watana
Creek drainage,the blocks will be wide and fl at and
more easily traversed.Where the banks are steeper,
the ice will be fractured into smaller blocks and
pile up as ice moves up from below and slides down
from above;these areas may be more d iffi c ul t for
caribou to cross.It is possible that some caribou
may be killed or seriously injured when crossing.
During the ice-covered reservoir period,the prevail-
ing northeast winds will tend to sweep the reservoir
clear of snow or at least will maintain a smooth,
flat surface.Drifting snow is thus expected to
accunul ate near the southwest end of the reservoir.
E-3-4l6B
-!
r
4.3 -Impacts -Watana Dall Sheep
proceeding to the least likely reaction (Banfield
1982 Personal Communication;Roseneau 1982 Personal
Communication).In any particular year,all four
responses will likely be exhibited by varying propor-
tions of the herd.
-The cari bou wi 11 manage to cross the impoundment
safely in the Watana and Kosina creek areas.
-The caribou will travel eastward and cross the
Susitna River in the vicinity of the Oshetna and
Tyone rivers on ice-covered flats.
The caribou will make hazardous crossings with
increased mortality.
-The caribou wi 11 refuse to cross the impoundment
and reverse direction.
The Watana impoundment should not cause any substan-
tial caribou mortality during the summer and fall
open-water period,but it may greatly influence the
movements of some cari bou duri ng that time.Cari bou
are excellent swimmers,but large lakes and swift
rivers can change the di recti on or timi ng of move-
ments.Skoog (1968)reported that "even though
caribou are excellent swimmers and generally take
readi ly to the water,frequently I have noted how a
movement wi 11 change di recti on upon encounteri ng a
large lake or river and will parallel the waterway
rather than cross it."Banfield and Jakimchuk (1980)
ADF&G 1982c)state that "caribou prefer to avoid open
water,II and that 1arge 1akes are often crossed at
narrow points or where islands provide interim
stopping points.It thus seems likely that caribou
approachi ng the reservoi r in the Watana Creek vi ci-
nity,for example,might parallel the shore to an
area where the impoundment is narrower.
(c)Dall Sheep
Anticipated and hytopthesized impacts to Dall sheep are
summarized in Table E.3.148.The most serious impacts to
Dall sheep include disturbance and harassment and the inun-
dation of portions of a mineral lick.Disturbance of sheep
at the lick is a major potential impact.
(i)Construction
E-3-417
4.3 -Impacts -Watana Dall Sheep
The three Dall sheep populations identified in the
Susitna Basin are most likely to be affected by the
project through disturbance (i.e.,aircraft traffic,
construction noise,presence of workers),habitat
loss,and increased access by hunters.Each of the
populations will be affected to a different degree as
a result of their distribution in relation to project
facil ities.
The Mount Watana popul ati on does not usually occur
near the impoundments,access roads,or borrow areas
at any time of the year,and is likely to be affected
only by low-flying aircraft crossing between the
Susitna and Talkeetna river drainages.Disturbance
from low-flying aircraft is also of concern with the
Portage-Tsusena Creek popul at i on.The Watana Hi 11 s
population will be most affected by the project
because of the partial inundation of a major mineral
lick on Jay Creek used by this population.As will
be discussed,the frequent disturbance of sheep at
the lick by project personnel and recreationists is
expected to be a more immedi ate and seri ou s impact
than will the eventual partial inundation of the
1i ck.
The impact of intensified human activity on Da1l
sheep populations is not completely understood,but
some general predictions can be made.If an animal
is excessively aroused,as from human disturbance,
the added cost of excitement or activity may inter-
fere with health,growth,and reproductive fitness
(Geist 1975).Ewes with lambs are particularly
sensitive to disturbances (Smith 1954,Jones et ale
1963).Recent studies of free-rangin9 ungulates have
founij that the heart rate of an lndividual is a
sensitive indicator of arousal,the first stage of an
alarm reaction to stress (Ward et ale 1976;MacArthur
et a1.1979,1982).These and other investigators
have demonst rated cons i stent heart rate responses to
disturbing visual or auditory stimuli,often in the
absence of overt behavi oral reacti ons.MacArthur et
ale (1982)reported on the heart rate response of an
unhunted population of mountain sheep (avis
canadensi s)to ai rcraft and vehi cl e traffi c.~
heart rate responses were associated with helicopter
or fixed-wing aircraft at distances exceeding 1300
feet (400 m)from sheep.They found that di rect
overflights at 100-275 feet (90-250 m)by helicopters
caused sheep to run for 2-15 seconds and elicited a
E-3-418
.....
....
.....
4.3 -Impacts -Watana Dall Sheep
2-3.5 x increase in heart rate.In Alaska,six
studies have included observations on the response of
Dall sheep to ai rcraft di sturbances (Andersen 1971,
Linderman 1972,Nichols 1972,Price 1972,Lenarz
1974,and Summerfield 1974),although only one of
these (Lenarz 1974)presented quantitative data.
Hel icopters usually evoked a greater response from
sheep than did fixed-wing aircraft.This is possibly
because hel i copters fly slower and closer to the
sheep and are generally more noisiest (especially
"rotor popping")(Andersen 1971,Linderman 1972,
Price 1972).No studies have been conducted to
determine the responses of mountain sheep to aircraft
flying at different altitudes,as have been conducted
with caribou and muskoxen.The reaction of Dall
sheep to low-flying aircraft is highly variable
(Linderman 1972 and Price 1972),although Linderman
found that sheep always reacted nervously and assumed
the alarm posture (Geist 1971b)until the disturbance
had passed.Lenarz (1974)found that "ewes"
(including young rams not discernible from females)
reacted more strongly to hel i copters than di drams.
Andersen (1971)and Price (1972)found that sheep
were more easily disturbed by aircraft when congre-
gated at mineral licks,which are usually located
lower on slopes away from escape cover.
The Watana Hills sheep population will be most
affected by the project because of the location of a
major mineral lick on Jay Creek.The area used by
sheep is a steep bluff extending from the creek
bottom at 200 feet (610 m)to the rim at 2450 feet
(747 m).A ri dge on the east si de of the creek
2252 feet (692 m)elevation)is also used.Approxi-
mately 42 percent of the 1i ck surface area wi 11 be
inundated each year when the Watana impoundment is at
its maximum 1evel 2190 feet (668 m)(668 m).How-
ever,during the months of maximum lick use (May and
June),the reservoir level will be approximately
2093 feet (636 m)(May 1)and 2100 feet (638 m)(June
1),and thus only about 22 percent of the lick will
be under water.Sheep appear to use the lower half
of the lick more frequently than the upper hal f
(ADF&G 1982d,no quantitative data provided)and,
therefore,these percentages may underestimate the
amount of soil that will be inundated.Most licks
are created and/or maintained by water action along
creeks or lakes,and it is unlikely that sheep will
discontinue use of the lick because of partial
E-3-419
4.3 -Impacts -Watana
inundation.Erosion caused by the reservoir may
enhance the lick by exposing new soil,but may also
1each important ions from the soil.Of greater
immed i ate consequence than the decrease in surface
area of the 1 ick is the disturbance of sheep using
the 1 i ck.Frequent vi sits to the 1 i ck (mostl y with
hel i copters)by resea rchers,other proj ect pe rsonnel ,
and vi si tors touri ng the proj ect area have undoubt-
edly affected the sheep using the lick.The lick is
far removed from adequate escape habitat,and these
frequent helicopter trips into Jay Creek for purposes
of viewing the lick could result in its abandonment
if conti n ued.Recreat i oni sts accessing the area by
boat after the impoundment has fill ed coul d have a
similar effect.
The consequences to the Watana Hills sheep population
if the Jay Creek lick is abandoned for any reason are
unclear.Several other mineral licks have been iden-
tified within the range of this population,but
because sheep have a demonstrated hi gh fi del ity to
specific licks,it is uncertain whether these alter-
native licks would replace Jay Creek.Many research-
ers have conducted chemical analyses of mineral lick
soils in an attempt to explain why sheep visit licks,
but the results have been conflicting or incon-
clusive.Contamination of samples from urine,feces,
and/or muddy water have been cited as potential
sources of error in these anal yses.Many studi es
have found that sodium is relatively abundant in lick
soils and is selectively sought by ungulates (see
Stockstad et al.1953 and Tan kersl ey 1981).Pl ants
other than halophytic species absorb only a small
percentage of the sodium present in the soil,and it
is therefore possible that forage species are unable
to supply the quantity of sodium needed by big game
(Stockstad et al.1953).Heimer (1973)found that
soil samples from high use sites within a mineral
lick contained large quantities of clay minerals
called zeolites which contain biologically available
cations of sodium,potassium,calcium,and
magnesium.
(d)Brown Bear
Anticipated and hypothesized impacts to brown bears are
summarized in Table E.3.149.Probable factors regulating
brown bear populations in the Susitna Basin and actions that
might affect populations are illustrated in Figure E.3.110.
E-3-420
.....
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4.3 -Impacts -Watana
Brown bear-human conflicts are a major concern of develop-
ment project planners in the north and are treated in this
secti on.Other impacts i ncl ude spring habitat loss,di s-
turbance,and impediments to movement.Indirect impacts
associated with increased access are likely,to be serious.
(i)Construction
The two major impacts of the project on brown bears
during the construction phase will be the loss of
spring feeding areas during and after clearing,and
direct mortal ity of bears resulting from bear/human
conflicts at camps,construction sites,and bear con-
centrati on areas.Unregul ated hunting by construc-
tion workers woul d al so have a maj or impact on brown
bears during this period.
Several food sources have been identified that appear
to be seasonally important to brown bea rs in the
Susitna Basin.These include spawning salmon in July
and August at Prai ri e Creek,early spring herbaceous
growth and overwintering'berries along the lower
slopes near the river bottom,widely scattered berry
patches on the benches above the ri ver,carri on and
moose calves near the river and its tributaries,and
vegetati on along tri butari es such as Deadman Creek.
Some bears may avoid areas of intensive human activi-
ty,thus affecting their movements between these
widely scattered food sources.However,because
brown bears range widely and frequent open habitats,
it is unlikely that the intensive human activities
near the damsite and borrow sites,or the presence of
a cleared impoundment area in the last year or two of
the construction phase,would prevent bears from
reaching food sources outside the intensively used
construction area.
The greatest impact on food sources during the first
few years of the construction period will occur near
the damsite,where facilities and human activities
will be concentrated.A much greater reducti on in
spring food availability will occur during and after
impoundment clearing.The availability of early
spring foods to brown bears will be reduced both as a
resul t of di rect habitat removal near the construc-
tion sites,and by alterations of bear movements
along the river.Because the food requi rements of
brown bears are so poorly understood,it is not
possible to equate losses in food supplies to losses
E-3-421
4.3 -Impacts -Watana
in number of bears.It is thought that the riparian
areas are most important to bears in early spring,
just after they emerge from dens.SnoWllel t occurs
sooner in these areas (part i cul arly on south-faci ng
slopes),maki ng overwi nteri ng berri es and green
growth available to bears when they have low energy
reserves.Moose calving is also concentrated in
riparian areas,and brown bears have been shown to be
effective predators of both adult and young moose
(Ballard et ale 1980).
The loss of early spring feeding areas near the con-
structi on site wi 11 probably not affect the popul a-
tion size or productivity of brown bears during the
short construction period.Reservoir clearing acti-
vities will cause a reduction in carry"ing capacity,
but it is doubtful that this alone would cause
measurable population effects in the one or two years
of the construction phase when clearing occurs.
Brown bears eat sparingly for several weeks after
emerging from dens during a transition stage from
hibernation to normal activity (Craighead and
Mitchell 1982).As food becomes increasingly
available;the bears'food consumption increases.
Craighead and Mitchell (1982)reported that bears in
Yellowstone Park during April and May continued to
util ize body fat stored the previous fall,and that
weight gains were not noticeable until late July and
August.Berry production appears to be highest on
the benches above the river (above the impoundment
level)where snowmelt occurs 1-3 weeks later than on
the south-faci ng slopes below 2200 feet.If bears
are abl e to subsi st on fat reserves for these few
weeks,a more abundant food supply w"il 1 become avail-
able.
Craighead and Mitchell (1982)also reported that
although brown bears feeding primarily on green vege-
tation in spring failed to gain weight,those secur-
ing high-protein food such as carcasses,the young of
big game species;or garbage maintained or increased
their weight.This suggests that a decrease in ungu-
late populations may have as great an affect on bear
condition in the spring as would a decrease in the
availability of green vegetation.If project person-
nel are not allowed to hunt,the effects of the pro-
ject on moose during the construction phase are
expected to be mostly distributional (as opposed to
changes in population size),and no changes in
E-3-422
I""'"
,
I
-.
....
4.3 -Impacts -Watana
caribou numbers are expected.Thus,it is unlikely
that noticeable changes in the number of brown bears
as a result of altered spring food availability will
occur during the construction period.During the
fill i ng and operation phases,however,the loss of
spring feeding areas will have a major impact on
brown bears.
Brown bears have one of the lowest reproductive rates
of any land mammal in North Jlrnerica (Bunnell and Tait
1978).This,coupled with the low densities of brown
bears in most parts of their range,makes the impact
of sustained high levels of mortality particularly
severe (Craighead et al.1974).Typically,causes of
direct bear mortalities during construction of pro-
jects in their range include killings in "defense of
life and property",control kills of nuisance animals
by appointed agency or project personnel (Cole 1971);
accidental deaths of bears during attempts to fright-
en or t~ap and transplant animals;and increased.
hunting and poaching pressure resulting from improved
access and higher numbers of people (Rogers et al.
1976,Nagy and Russell 1978,JFWAT files).Acciden-
tal deaths of bears from bl asti ng or destructi on of
dens also occur but are less common (JFWAT files).
Human activities related to the Trans-Alaska pipeline
project (TAPS)resulted in a minimum of 11 brown bear
and 30 black bear deaths (JFWAT files).One of the
most seri ous problems encountered duri ng TAPS con-
struction resul ted from the attraction of bears to
areas of human activity.Bears quickly discover and
util ize jmproperly handl ed food and garbage at camps,
worksites,or dumps (Barnes and Bray 1967,Crai ghead
and Craighead 1972a,Meagher and Phillips 1980).The
effects of bears'concentrating at artificial food
sources such as dumps are not clearly understood,but
there is some evidence that higher cub mortality from
predation by adults and higher disease and parasite
loads may result when bears are concentrated (Cole
1971).Brown bears from hunted populations such as
that in the Susitna Basin are less likely to be
attracted to camps and dumps than are those in
unhunted populations,but some brown bears can still
be expected to frequent these areas.
Human activity in bear habitat poses problems for
peopl e and thus for bears.Fatal attacks by bears
occasionally occur when artificial food sources
E-3-423
4.3 -Impacts -Watana
attract habituated bears to sites of human activity
(Crai ghead and Crai ghead 1972a,Hamer 1974,Herrero
1976).Females with cubs,very old bears,and habit-
uated bears pose the most serious threats (McArthur
1969).Besides serious maulings,minor injuries such
as bites and scratches frequentl y result from at-
tempts to feed bears (Eager and Pelton 1980).
Extremel y seri ous bear/human confl i cts occurred
during the TAPS project (JFWAT files).
There are several specific areas and seasons where
human/bear conflicts might occur.Areas where bears
congregate to feed on salmon in late summer are like-
ly to be attractive to project personnel as fishing
sites.Brown bears tend to concentrate nea r the
river to feed on vegetation during early spring,soon
after emerging from dens;thus,bear/human encounters
near the construction site and borrow sites may be
frequent at that time.The proposed camp is 1ikely
to be frequented by bears if proper food storage and
disposal methods are not implemented.Also,the camp
is located in prime berry habitat used by bears in
late summer and early fall.The ongoing bear studies
will provide the information needed to further iden-
tify such bear concentration areas.
Bears are reported as one of the large mammals more
sensitive to aircraft disturbance (Klein 1974,
McCourt et ale 1974).The reactions of bears to air-
craft have been recorded in several studies (Quimby
1974,Ruttan 1974,Harding 1976);there is much
individual variation in their reactions,probably
related in part to previous experience (Linderman
1974,Pearson 1975,Harding and Nagy 1977).Bears
seem to react more strongly to hel icopters than to
fixed-wing ai rcraft (Quimby 1974,Harding and Nagy
1977).Low-flying aircraft near feeding sites could
affect the productivity of brown bears if disturbance
is frequent enough.
The impacts of the project on brown bears downstream
from the Watana dam will be 1 imited mostly to ai r-
craft disturbance and increased hunting,since down-
stream flows will not be-altered until the filling
phase.No measurable changes in the number of moose
or other important prey speci es are expected,
although there may be some noticeable shifts in th.e
distribution of prey species away from the construc-
tion sites.Fish and mammal populations downstream
E-3-424
4.3 -Impacts -Watana
from the Devil Canyon site would be affected primari-
ly by increased fishing and hunting pressure,and no
impact on brown bears shoul d result gi ven the current
hunting and fishing regulations.
(i i)Filling and Operation
The loss of habitat as a result of the impoundment
clearing and fill ingand the partial avoidance of
project facil ities will have the greatest impact on
brown bears duri ng the fi 11 i ng and operati on phases.
Ind i recteffects of decreased moose popul ati ons and
increased hunting by people will also have measurable
effects on brown bears.There is also some potential
for the impoundment to interfere with bear movements,
particularly during the spring.
The impoundment will affect the brown bear population
primari 1y through decreased avai 1abil ity of moose,
berries and green vegetation.Although the loss of
earl y spri ng feedi ng areas near the damsite duri ng
the construction period is not likely to measurably
affect the population,the loss resulting from
impoundment of the ri ver will decrease carryi ng capa-
city.Brown bears must bui 1d up 1arge fat reserves
during the six-month period that they are out of dens
to sustain them through the winter and early spring.
Following the 1981 berry crop failure,Miller (1982
Personal communication)reported that two of the four
females expected to have cubs in 1982 did not,
suggesting that the poor nutritional condition of
femal es in the fall may have caused a lower produc-
tivity the foll owi ng year.Pelton (1982)reported
for bl ack bears that years of poor berry or acorn
production can result in delayed first estrus,
decreased litter sizes,and increased incidence of
barren females.In addition,overwintering berries
appear to be a particularly important spring food for
some bears.Yearlings,which emerge from dens in
poor condition and suffer higher rates of mortal ity
than other age classes,may be particularly sensitive
to loss of overwintering berries as a spring food
source.The permanent loss of habitat and early
spri ng foods in the impoundment area wi 11 therefore
cause a decrease in the carryi ng capacity of the
project area for brown bears.The decrease in the
number of moose availabl~to bears,in combination
with the loss of berries and other vegetation and any
alteration of plant phenology in the impoundment
E-3-425
4.3 -Impacts -Watana
zone,will cause an even greater reduction in the
carrying capacity of the area.
The impoundment is not expected to be an absol ute
barrier to brown bear movements,except possibly dur-
ing the spring.Some interference with movements
between food sou rces will occur,but the number of
bears affected and the consequnces in terms of pro-
ductivity or survival cannot be predicted.Brown
bears usually emerge from dens in Apri 1,and most
have entered new dens by the end of October.Thus,
the reservoi r wi 11 be ice-free du ri ng most of the
time bears are out of their dens.Brown bears com-
monly swim long di stances in the ocean to offshore
islands (Miller and Ballard 1982,Roseneau 1982
Personal communication),and the open water in the
reservoir should not physically obstruct crossings.
The ice on the reservoir is expected to begin melting
in early March,and the reservoir should be ice-free
by late May to early June (Bredthauer and Drage
1982).During April and May,bears attempting to
cross the reservoir will be confronted with ice
shelves and blocks,wide mudflats,and thin and
broken ice conditions.There will also be open-water
conditions near the intake structures and downstream
from the dam.It is not known whether one or more of
these factors might deter bear crossings,but these
spring conditions would be more likely to affect
movements than woul d the open water 1ater in the
summer.
Indirect impacts on brown bears downstream from
Watana wi 11 result from reduced popul at ions of moose
and salmon and from increased hunting along the
transmission corridor.Moose and salmon studies are
bei ng conducted along the lower ri ver in an attempt
to quantify project impacts.The carryi ng capacity
of the areas adjacent to the river will decrease if
salmon and moose populations are substantially
reduced.
Hunt i ng pressure on brown bears wi 11 probably
increase in the upper Susitna basi n because of the
improved access afforded by the reservoi r and access
road.Also,many of the workers who helped to con-
struct the dam may retu rn to the area to hunt.Thi s
increased hunting pressure will likely result in
lower bear densities and a younger age structure in
the brown bear population (ADF&G 1982e).
E-3-426
-4.3 -Impacts -Watana
(e)Bl ack Bears
Anticipated and hypothesized impacts to black bears are
summarized in Table E.3.150.A large proportion of the
acceptable black bear habitat in the middle basin will be
eliminated.Disturbance will also be a serious impact,as
will black bear/human conflicts.
-
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(i)Construction
The long-term impact of the Watana development on
black bears will be much greater than that for brown
bears,si nce the impoundment and other project faci-
1ities will remove a large proportion of acceptable
black bear habitat in the Watana area.However,
habitat loss may not be the most seri ous impact on
bl ack bears duri ng the fi rst few years of the con-
struction period,when attraction to artificial food
sources,disturbance of bears at denning and feeding
sites,and increased levels of hunting are more like-
ly to have serious effects (see Figure E.3.111).
Bl ack bears in the vicinity of the proposed Watana
impoundment are restricted to a band of conifer
forest adjacent to the river.Between Watana Creek
and the Tyone Ri vers,thi s band of forest becomes
increasingly constricted.The construction site,
borrow sites,camp,ai rport,and other facil iti es
will remove a large proportion of the black bear
habitat,thus concentrating the bears into the limit-
ed remaining areas.Black bears are more likely to
frequent the camp and constructi on sites than are
brown bears,and this will cause problems for both
people and bears (see 4.3.l[d]).Deliberate feeding
of bears by project personnel at construction sites
will intensify the problem.
Borrow sites D and F are located in the tablelands
and are used by black bears foraging for berries in
late summer (ADF8cG 1982e).Bears will be affected
both by the di rect removal of thi s ri ch food source
and by a greater 1i kel ihood of contact with humans,
which could lead to some bear mortalities.The other
borrow sites are in forested areas used by bl ack
bears throughout the yea r,and the mi ni ng of con-
structi on materi al s from these sites will cause a
reduction in the availabil ity of denning sites and
feeding areas.
E-3-427
4.3 -Impacts -Watana
Black bears in the 5usitna Basin typically den at
elevati ons below 3,000 feet,and 9 of the 13 known
black bear den sites in the Watana impoundment area
will eventually be flooded.Assuming that other dens
occur above or below the impoundment level in the
same ratio,69 percent of the black bear denning
habitat in the Watana impoundment vicinity will be
lost.5i nce dens are concentrated near the ri ver
where human activity will be greatest,there is also
the potential for disturbance to cause den
abandonment or to make some denning areas
unacceptable.Many of the dens sites were reused by
the same or a different bear,which may indicate a
scarcity of acceptable sites.Human activity on the
ground and 1 ow-fl yi ng ai rcraft can both cause den
abandonment.As discussed for brown bear,den
abandonment in winter when the ground is frozen may
result in a bear's death.
Because bl ack bears will be concentrated near the
river and may have increased movements while search-
ing for food,any increase in hunting pressure during
the construction period could have a substantial
effect on the population.If black bears do increase
their movements away from forested areas,as they do
during berry crop fail ures (ADF&G 1982e),there is
al so a potential for increased mortal ity caused by
encounters with brown bears.
(ii)Filling and Operation
Bl ack bears will be affected in several ways duri ng
the clearing of the impoundment area and initial fil-
ling peri od.The loss of feedi ng areas,di sturbance
at den sites,and increased contacts with people will
all result in severe habitat degradation within and
adjacent to the impoundment area.Bears occurring in
the impoundment area will likely increase their move-
ments away from the ri ver,thus i ncreas i ng contacts
with brown bears and hunters.There is little like-
lihood of bears being drowned while in their dens
during reservoir filling,since winter flows into the
reservoi r wi 11 be very low,and most of thi s flow
will be released downstream.
After filling,it is unlikely that a viable resident
black bear population will exist upstream from Watana
Creek.Transient bears may use areas adjacent to the
E-3-428
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4.3 -Impacts -Watana
impoundment~and a few bears may reside there year-
round.However~the lack of denning areas and ade-
quate forest stands near the remaining food supplies
will severely limit the resident population.These
bears will also be quite susceptible to hunting along
the reservoir margin.Many bears residing downstream
from Tsusena Creek made movements in 1980-82 upstream
to feed on berries~and the road and other permanent
facilities may interfere with these movements.Other
long-term impacts are 1i ke1y to be simil ar to those
for brown bears (see4.3.1(d)).Black bears~like
brown bears~are able to swim long distances~and the
open water in the impoundment should not be an abso-
1ute barri er to thei r movements.Some effects on
bear movements~however~can be expected.Since
black bears.in the Watana watershed wi 11 be subject
to seriolJs habitat 10ss~the cumulative impacts to
vegettion and prey populations are likely to be of
greater importance than for brown bear.
Downstream effects of the Watana development on black
bears are 1i ke1y to be much 1ess severe.Impacts on
salmon spawning areas~aircraft disturbance~and
increased hunti ng wi 11 probably have the greatest
effect on the popul ati on.The expected successi ona1
changes in vegetation are not likely to have a
noticeable effect on the population~nor will any
open water areas during winter~since bears will be
in dens at that time.The importance of sal mon to
downstream bears is unknown ~but several bears from
the middle basin moved downstream to feed on salmon
duri ng a berry crop fai 1ure~and bears are commonly
seen along spawning sloughs.in late summer (ADF&G
1982e).Twenty percent of the sal mon rad i o-tagged
during studies downstream were eaten by .bears
(Miller 1982 Personal communication).However~bear
scats found along salmon streams comprise mostly
berries,and thus the importance of salmon to these
bears is uncertain.Bear studies downstream from
Devil Canyon will be intensified in 1983~and conse-
quently ~the food habi ts of downstream bears wi 11 be
better defined at that time.
(f)Wolf
Anti ci pated and hypothesi zed impacts to wolves are summa-
rized in Table E.3.151.Wolves may be affected by construc-
tion and operation of the Watana development by some loss of
den and rendezvous sites~by disturbance~by increased
E-3-429
4.3 -Impacts -Watana
hunting (see Section 4.3.5),and indirectly,by loss of food
sources.The Watana pack in particular may be seriously
affected by the loss of habitat for the major prey species -
moose,within their territory.
No known dens or rendezvous si tes wi 11 be flooded or de-
stroyed by the present construction zone plans.Some den
and rendezvous sites that have not been located may be
destroyed,but because potential sites are relatively
abundant in the Susitna Basin (ADF&G 1982f),this would not
have a serious effect on wolf populations.
Under most ci rcumstances,wol yes readil y habituate to man-
made disturbance (Van Ballenberghe et al.1975,Milke 1977).
The major exceptions to this are disturbances at den sites
in spring.During Susitna baseline studies (ADF&G 1982f),
human disturbance at three den sites caused early abandon-
ment of all three,the adults movi ng the pups to new loca-
tions.In these cases,the pups were probably a month old
and no pup mortality was noted.ADF&G (1982f)speculated
that younger pups might be more likely to die if moved from
the whel ping den prematurely.Abandonment of dens after
disturbance has also been noted in other areas of Alaska and
in Canada (Carbyn 1974,Chapman 1977).Aside from disturb-
ance at dens,disturbance alone is unlikely to cause notice-
able changes In the distribution of wolves or home range use
of individual packs.
A seri ous impact of increased i nteracti ons between humans
and cani ds (wo1 ves and foxes)is the threat of ex posure to
rabies.That wolves (and bears and foxes)do habituate to
the presence of humans was demonstrated by problems encoun-
tered duri ng the construct ion of the Trans-Al aska poi pel i ne
(Milke 1977).Wolves were fed deliberately and were allowed
to scavenge on unburned garbage at constructi on sites and
camps.As a resul t,many animal s became severe nui sances
and were killed.In addition,instances of workers being
bitten and requiring hospitalization and occasionally rabies
vaccine occurred.
Loss of food sources through development impacts on prey
species will be another impact of the Watana development on
wolves.Wolves in the middle Susitna Basin prey primarily
on moose and to a lesser extent on caribou.Caribou popula-
tion levels are not likely to be seriously affected by the
Watana development.but moose populations will be reduced.
The extent to which this reduction actually affects wol ves
depends on the extent to which wolf populations are limited
by food availability rather than by human exploitation.and
E-3-430
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4.3 -Impacts -Watana
on the distribution of the reduction in prey availability
relative to territories of individual packs.
Van Ballenberghe et ale (1975)reviewed the available liter-
ature on factors controlling wolf populations.They
believed that while social factors such as territorial ity
and stress were the ultimate factors controll ing popul ation
1evel s,an abundant food source lowered the threshol d for
action of social factors.They suggest that food is the
main factor permitting the development of dense wol f popu-
lations (Figure E.3.112).
There are few data to indicate wolf population trends in
relation to population trends of moose and caribou in the
Susitna Basin.However,the consistently high harvest of
wol ves through the 1970s (Secti on 4.2.1[f])suggests that
the low caribou population and declining moose population in
the early 1970s (Section 4.2.1 (a)and (b))did not cause a
substantial reduction in wol f numbers.
Wolf population levels are currently controlled by exploita-
tion rates.Close to half the middle basin wolf population
is removed each year by legal and illegal hunting (Section
4.2.1 [f]).In the lHely event that this situation con-
tinues,the reduction in the moose population as a result of
the proj ect shoul d have 1ittl e effect on the regi onal wol f
population.Only if the harvest level is greatly reduced
through better enforcement and/or al tered management prac-
tices,will the density of moose and caribou become the
major factor controlling the wolf population.
On the other hand,the Watana pack will be seriously affect-
ed by i nundati on.As a result of habitat loss,reducti ons
in the moose population,and disturbance near den and
rendezvous sites,it can be assumed that this pack of up to
14 wolves will be eliminated.If prey densities become the
major factor control 1 ing wol f populations,reduced moose
numbers and altered cari bou movements woul d affect the
potential carrying capacity of the area and cause measurable
changes in the productivity and territory size of as many as
10 other packs.Several wol f packs will al so experience
positive impacts because of improved hunting conditions
along the impoundment shorel ine,lower brown bear numbers,
and altered distributions of moose and caribou.
Di spl acement of prey an imal s from the reservoi r area may
result in a temporary increase in wolf density in adjacent
areas.However,the loss of habi tat from the impoundment
may cause adjustment of territory boundaries with
E-3-431
4.3 -Impacts -Watana
neighboring.packs,and a decrease in both wolf and moose
density from temporarily higher levels would ensue.
(g)Wolverine
Anticipated and hypothesized impacts to wolverine are summa-
rized in Table E.3.152.The Susitna Hydroelectric Project
will have both positive and negative effects on the wolver-
ine population in the middle basin.Wolverines will be most
affected by changes in winter food availability and by high-
er trapping mortality resulting from improved access and a
larger human population in the area.Other factors such as
a local i zed avoi dance of camps and roads,di sturbance from
aircraft and construction activities,and habitat loss
caused by the impoundments and other project facilities are
not likely to greatly affect the number or productivity of
wolverines in the Susitna Basin.Loss of den sites is not
likely to be a problem since wolverines den in a variety of
habitats,generally on the surface of the ground under snow.
Downstream from Devi 1 Canyon,wo 1veri nes are 1i ke1y to be
measurably affected only by any increase in trapping pres-
sure resulting from the project.Each of these factors w;11
be discussed in greater detail in the following sections.
The area in northwestern Montana studi ed by Hornocker and
Hash (1981)contai ned a 1arge reservoi r 32.2 mil es (48 km)
long and up to 4.4 miles (6.5 km)wide,and thus some data
are available on wolverine movements and ranges in relation
to a large impoundment.They reported that lithe size and
shape of ranges were not affected by rivers,reservoirs,
highways or major mountain ranges.1I Magoun (1982)stated
that,although topographi c features were not physi cal bar-
riers to wolverine movements,they did appear to influence
the shape of home ranges to some extent.Rivers,ridges,
drainage divides,and well-defined breaks in habitat types
often coi nci ded wi th home range bounda ri es in her study
area.Male home ranges appeared to be less affected by
topographical features than did femal e ranges.Some home
range boundaries in the middle Susitna Basin coincide with
topographical features (see Figure E.3.98),but no clear
relationship between the major features and most home range
boundaries is evident.It is possible that the Watana
impoundment might serve to'separate home ranges once it is
in operation.
Based on the estimate of about one wolverine per 40,320
acres (163 km 2 )derived in Section 4.2.1{g),the direct
loss of over 50,900 acres (206 km 2 )caused by the impound-
ments,access roads,camps,and other project features would
E-3-432
,I''''
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4.3 -Impacts -Watana
lower the carrying capacity by about two wolverines.How-
ever,winter food supplies are usually greater at the lower
elevations most affected by the project facilities.Changes
in the avail abi 1ity of wi nter food may affect wo 1veri ne
movements,densities,and productivity;and therefore,it is
important to consider these changes in some detail.
-
,.....
(h)
The Watana impoundment will cause a decrease in winter food
availability.Because a relatively high proportion of the
forested area will be inundated,there will be a substantial
decrease in the avail abi 1ity of small mammals and grouse
used by a few wol veri nes duri ng wi nter.The si ze of the
moose population in the vicinity of the Watana impoundment
will decrease during the license period,but there may be an
increase in the number of ungulate carcasses available to
wolverine.Some mortality of both moose and caribou is
expected from floating debris,thin ice conditions,and
large mud flats in the drawdown zone;and predation by
wolves and brown bears may increase along the shores of the
impoundment.Hi gher wi nter mortal ity of moose near the
impoundment is also expected during winters of moderate to
deep snow.It is not clear whether the more rapid turnover
of the moose population in the middle basin will offset the
lower density of moose ,and small mammals.The effects of
improved access from the roads and impoundment on wolverine,
including increased trapping mortality and human presence,
is discussed in Section 4.3.3(g).
Be1ukha Whale
The majority of the Cook Inlet population of be1ukha whales
appears to concentrate near the mouth of the Susitna River
during the calving period.Studies were undertaken in 1982
to address the concern that project-related changes in water
temperatures or anadromous fish runs at this critical period
might interfere with calving success.For example,Seargent
(1973,cited in ADF&G,unpublished report on 1982 Phase 1
Report)attributed the elimination of calving by belukhas in
the St.Lawrence River to hydroel ectri c development on the
Manicougan and Outardes rivers and subsequent alterations in
water temperatures.
Although water temperatures rel eased from the dams wi 11 be
0_7°F (0-4°C)warmer than natural temperatures,the dilution
effect of other rivers and temperature exchange of the river
with the ai r and ground wi Tl result in no post-project
difference in water temperatu res at the mouth of the ri ver
during May and June.Only 7,650 cfs of the 55,930 cfs post-
project inflow into Cook Inlet in May will be from the
E-3-433
4.3 -Impacts -Watana
Susitna River (both dams operating).In June,only 8,150 of
105,702 cfs will be contributed by the Susitna.Thus,the
dil ution factor of other water sources and 151 river mil es
of temperature exchange with the envi ronment wi 11 result in
similar pre-and post-project water temperatures at the
mouth of the river during calving.
Belukhas are thought to feed on the large runs of anadromous
eul achon (a major run occurred between June 1-9,1982)and
on adult and out-migrating salmon.Eulachon are thought to
spawn in the lower mainstem and in the lower tributaries of
the river (McPhail and Lindsey 1970:198),and the project
shoul d have no effect on the number of eul achons avai 1ab 1e
to belukhas.However,eulachon investigations are currently
being conducted in the Susitna River to verify this predic-
tion.If all salmon spawning habitat in the sloughs up-
stream from Talkeetna were lost,about 5-8 percent of the
salmon available to belukhas would be unavailable.Given
this small potential decrease in food supply,the necessity
of applying a correction factor of 2 or 3 times the number
of belukhas counted during surveys (because of silty waters
and submerged whal es),and the fact that it cannot even be
determined whether calves are present during surveys,it is
extremely unlikely that any measurable decrease in the
belukha population would occur as a result of the project.
(i)Beaver
The beaver population along the Susitna River is likely to
increase during the license period as a result of the Watana
development.Beneficial effects will occur mostly down-
stream from the dam as a result of regulated flows.Antici-
pated impacts to beaver are summarized in Table E.3.153.
(i)Construction
No active beaver lodges have been located during
surveys of the impoundment area,borrow sites,camp
sites,airport location,or damsite (Gipson et ale
1982),and,therefore,beaver should not be affected
by construction and clearing activities at these
sites.
(ii)Filling and Operation
No beavers are known to reside in the impoundment
area,and therefore,the flooding of this area will
not affect this furbearer species.The reservoi r
will be of 1 ittl e val ue to beavers after fi 11 i ng
E-3-434
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,..,.,
,
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4.3 -Impacts -Watana
because of the annual drawdown.A few beavers,how-
ever,may pers i st in us i ng the reservoi r area.Each
year for the past 12 years,beavers have attempted to
buil d lodges and food caches on Will i ston Lake in
British Columbia,which has an annual drawdown of
about 50ft (15 m)(Bonar 1982 Personal communica-
tion).One innovative colony there has built its
lodge on a raft of floating logs,which moves up and
down with the water level;whereas another colony has
a series of burrows extending down to the minimum
d rawdown 1eve 1•
Duri ng fill i ng,the ri ver is to be passed di rect 1y
through the dam during the winter months,and thus,
the only effect of tt'\e dam on downstream flows wi 11
be during summer.During the operation phase,·down-
stream fl ows will be higher than present in the
winter,but lower in summer.
No beavers currently occur in the river reach between
Watana and Devil Canyon,and the estimated 70 beavers
between Devil Canyon and Talkeetna were found mostly
in side channels,~loughs,and clearwater areas
(Section 4.2.2[aJ).Although swift currents in the
main channel probably contribute to these low densi-
ties,the greatly fluctuating water levels,ice
scouri ng events,and low abundance of early succes-
sional vegetation are probably the major limiting
factors (Figure E.3.113).Another limiting factor is
the depth of water beneath the ice in winter.
Beavers require at least 1.5 ft (0.5 m)of open water
under the ice for access to food caches and lodge
entrances (Scott 1940,Hakala 1952).Since winter
water depths are now much less than those in summer,
the winter flows determine which areas are suitable
for year-round occupation by beavers.
Any site currently occupi ed by beavers shou1 d still
be available post-project,since winter flows will be
higher than at present.In addition,many areas now
subject to freeze-out will also be available for
colonization by beaver.The increased availability
of ear1y-successi ona1 vegetati on,reduced i ce-scour-
i ng,1ack of an ice cover in the Watana-Devil Canyon
reach,more stable year-round flows,and lack of
floods whi ch destroy food caches and.other beaver
structures wi 11 all result in improved downst ream
habitat for beaver.Beaver habitat south of
Talkeetna may also be enhanced as a result of the
E-3-435
4.3 -Impacts -Watana
increased occurrence of favored food plants,but the
more unstabl e water 1evel s resulti ng from increased
contributions from other rivers and tributaries will
dampen this effect.
If construction camp personnel and their families are
allowed to trap in the area,beaver populations will
be affected both along the Susitna River itself and
in the lakes and creeks on either side of the river.
(j)Muskrat
Anticipated impacts on muskrat are summarized in Table
E.3.153.Muskrats will be affected primarily as a result of
improved access for trappers.Some habitat loss withi n the
borrow sites and impoundment zone will also occur;however,
muskrats may benefit from additional beaver ponds downstream
from the project (Section 4.3.1[i]).With the exception of
trapping mortality,the net impact on the muskrat population
should be negligible.
Of the 103 1akes surveyed for muskrat si gn in spri ng 1980,
17 occurred within borrow sites D or E or the impoundment
zone (Table E.3.154);only 5 of these lakes had muskrat
pushups (Gipson et ala 1982).A total of 13 pushups were
observed on these 5 1akes,but the number of musk rats thi s
represents is unknown (pushups are temporary structures,and
one muskrat can create many of these during a winter).A
1 ikely estimate of the number of muskrat to be lost as a
result of thi s habi tat loss is 5 to 10 animals.Improved
downstream habitat will compensate for this loss.
Muskrats are extremely susceptible to water level fluctua-
tions (Bellrose and Brown 1941),and usually find braided
rivers poor habitat because of 1ack of forage and burrow
sites (Brooks and Dodge i981).As such,there is 1 ittle
potential muskrat habitat in the active floodplain down-
stream from the Watana damsite.Many muskrat probably
occupy beaver colony sites (Curatolo et ala 1981)along the
Susitna River that are outside the active floodplain.Below
Montana Creek good muskrat habitat occurs in 01 d channel s
now functioning as clear-water seeps which will not be
affected by the project (Bredthauer and Drage 1982).
If construction camp personnel and their families are
allowed to trap in the area,muskrat populations throughout
the lakes lying on either side of the Susitna River could be
seriously affected.Gipson et ale (1982)found muskrat sign
in these lakes and noted their vulnerability to trapping.
E-3-436
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4.3 -Im~acts -Watana
(k)Mink and Otter
(i)Upstream Effects
Anticipated and hypothesized impacts to mink and
otter are summarized in Table E.3.155.Because mink
and otter are moderately abundant in the middle
Susitna Basin (see Section 4.2.2 [c,d])and are
dependent on aquatic and semi-aquatic habitats along
the Susitna River and its tributaries,construction
and operation of the Watana dam may have substantial
impacts on these species.The most important effects
include loss of habitat,reduction of food supplies,
increased disturbance,and barriers to movement.
Clearing and flooding of the impoundment will elimi-
nate a substantial proportion of good qual ity otter
and mink habitat.High quality habitat for these
semi-aquatic furbearers is generally characterized by
moderate-to-sl ow-fl owi ng streams and ri vers wi th
well-wooded banks.Ponds with abundant food,deep
and stable water conditions,and an irregular shore-
1i ne al so appear to be good habitats (Hodgdon and
Hunt 1953,Knudsen 1962,Barber et al.1975).
Because the impoundment wi 11 result ina 1arge draw-
down zone,it is unl"ikelythat the reservoir will be
heavily utilized by mink or otter.Small declines in
water levels (e.g.,less than 3.3 feet [l m])may
actually benefit mink during the winter by creating
air spaces under the ice that would allow them to
hunt more easily (Erri ngton 1943,Harbo 1958).How-
ever,the large drawdown area of the Watana dam will
probably be detrimental to otter and mink;it will
isolate their bank dens from the reservoir during the
winter and will probably reduce prey availability.
The extent to which otter and mink habitat will be
reduced and the effects on local populations are
difficult to assess.The impoundment wi 11 flood
approximately '53 miles (85 km)of the mainstream
Susitna River.In addition,portions of a number of
tributaries will be inundated by the impoundment;
these include Deadman Creek (2.3 miles of stream will
be inundated at maximum fill [3.7 km]),Kosina Creek
(4.2 miles,6.8 km),Jay Creek (3.2 miles,5 km),.
Goose Creek (1.2 miles,1.9 km),and the Oshetna
River (2.0 miles,3.2 km).The lower reach of
Tsusena Creek wi 11 be di sturbed by gravel removal.
E-3-437
4.3 -Impacts -Watana
It is not known what these losses represent in terms
of a proportionate reduction of available mink and
otter habitat.
Clearing and flooding of the impoundment area will
reduce prey availability for otter and mink.Clear-
ing of forest cover will reduce the availability of
some mi nk prey such as sma 11 mammal s and waterfowl.
Effects of erosion and consequent siltation,as well
as effects of dust that are associated with clearing
may also reduce the availability of fish and crus-
taceans.Flooding of the reservoir will probably
result in further reductions in prey availability;
crustacean distributions and productivity will
probably be altered by the drawdown zone;and the
species composition,abundance,and distroibution of
fish will change.In addition,because the reservoir
will greatly expand the amount of aquatic habitat,
fish wi 11 be 1ess concentrated than they are at
present and more di ffi cul t for otters and mi nk to
capture.The net result of these changes,in addi-
tion to the change of shoreline habitats,will be an
avoidance of the reservoi rs by mi nk and otter.The
effects on productivity associated with these dietary
changes are unknown.
Clearing of the reservoir site and construction
activities,particularly in close proximity to
streams and ri vers,may di sturb mi nk and otter and
may result in interference with daily activities or,
in extreme cases,an avoidance of the area.Densi-
ties of the European otter (Lutra lutra),a species
closely related to river otter,along the River Terre
in Engl and appear to be inversely rel ated to the
amount of human disturbance (recreational fisherman)
and the amount of clearing of woodland cover along
the river banks {1¥lacDonald et al.1978).Because
recreational use of the upper reaches of streams
along the north side of the impoundment will probably
increase during construction and operation,and
because the upper reaches of these streams may repre-
sent a moderate proportion of the remaining high
quality habitat for semi-aquatic furbearers,disturb-
ance effects on mink and otter could be important.
(ii)Downstream Effects
Alteration of the river hydrology and vegetation
communities as a result of the Watana dam has already
E-3-438
-
-4.3 -Impacts -Watana
been discuss.ed (Section 3.3.1).Both of these fur-
bearers commonly concentrate in open water stretches
of rivers and streams in winter (Barber et a1.1975),
and therefore,the reach of permanently open water
downst ream from the Watana dam may benefit small
numbers of mi nk and otter.Major impacts on these
species are not expected downstream from the dam.
F-
i
~,
-.
,
(1 )Coyote and Red Fox
Coyotes occur in the Watana development area,but they are
so uncommon that development activities are unlikely to have
a quantifiable effect on them.
Coyotes do not appear to avoid areas of human activity;how-
ever,no studies have specifically evaluated the effects of
human disturbance on this species.Ferris et a1.(1978)
demonstrated a si gni fi cant preference of coyotes (based on
wi nter track count surveys)for an area within 656 feet
(200 m)of a section of an interstate highway in Maine
relative to an area 656-1312 feet (200-400 m)from the high-
way.Track surveys also indicated that coyotes occasionally
used the right-of-way as a hunti ng or travel route.Penner
(1976)similarly concluded that coyotes preferred large
cleared areas and avoided undisturbed habitats within an oil
sands development area in northwestern Alberta.
Coyotes are likely to exhibit a significant increase in
population level in the development area only if wolves are
el imi nated.Wo1 ves wi 11 exc1 ude coyotes from thei r ranges
through physi cal aggressi on when encountered.On 1y when
wolf numbers are extremely low and packs are eliminated will
resident wolves allow expansion of coyotes into their terri-
tories.If wolves are locally exterminated and excluded
from portions of their territories near the development,
coyotes may colonize localized areas in low numbers.
Anticipated impacts on red foxes are summarized in Table
E.3.156.The major impact on red foxes will probably result
from trapping by construction workers and killing of
nuisance animals at camps and construction sites.Habitat
loss from flooding of the impoundment will not have a great
impact on faxes,since most individuals apparently utilize
areas above the high water line of the impoundment (2140 ft,
666 m elevation)during winter seasons when food availabil-
ity is most 1imited,and areas to the east of the impound-
ment on the Lake Loui se f1 ats.Fox dens typi cally occur at
elevations of 3280-3937 feet (1000 m to 1200 m)and no foxes
or fox sign were found along the Susitna River or the lower
E-3-439
4.3 -Impacts -Watana
reaches of its tributaries in late winter or spring during
baseline studies (Gipson et ale 1982).Foxes did occur
along the Susitna at other seasons.An abundance of arian
and small mammal prey would be available for foxes during
summer and fall,and loss of hab i tat along the ri ver woul d
probably have negltgible or minor effects.
Red fox similarly do not appear to avoid areas of frequent
human activity.Observations of red fox and the location of
den sites in relation to the main road in Denali National
Park showed that red foxes did not avoid areas of frequent
human use and that in some cases woul d habituate to human
disturbances (Tracy 1977).Red foxes in Gatineau Park,
Quebec,appeared to commonly use areas in the immedi ate
vicinity of human disturbance and showed little avoidance of
a reas frequented by snowmobil ers (Neumann and Merri am
1972)•
Foxes away from den sites habituate to human activity so
readily that they can become a nuisance at construction and
campsites if they are fed or allowed to feed on garbage
(Mi 1ke 1977).The presence of scavengi ng foxes frequently
leads to workers being bitten and occasionally needing
hospitalization for rabies vaccine (Milke 1977).It also
often leads to the destruction of the foxes.
Although the fox population in the Susitna Basin is small
(Section 4.2.2[f]),it is apparently a source of juveniles
that di sperse to adjacent areas (Gi pson et a 1.1982).An
increased take of foxes from currently low levels is expec-
ted because of improved access and residency of construction
personnel and may eliminate this source of dispersing indi-
viduals.
(m)Other Furbearers
This group includes species that occur primarily in forested
habitats--marten,lynx,short-tailed weasel and least
weasel.Anticipated impacts are summarized in Table
E.3.157.Impacts on marten are discussed in greatest
detail.As mentioned previously (Section 4.2.2[c]),marten
have hi storically been and conti nue to be economi cally the
most important furbearer in the vicinity of the impoundment
zones.Lynx are very uncommon in the middle Susitna Basin.
Weasels are probably quite common,but there is little
specific information on their abundance and distribution in
the basin.
E-3-440
-
4~3 -Impacts -Watana
All of these sped es wi 11 suffer primari ly as a resul t of
the loss of forested habitats to the impoundment,borrow
sites,and other project facilities.Probable factors
regulating marten populations in the Susitna Basin and
actions that might affect populations are illustrated in
Figure E.3.114.Gipson et ale (1982)have estimated the
number of marten in the winter population directly impacted
by loss of habitat in the Watana and Devil Canyon develop-
ments through a model based on the following data and
assumptions:
-Adult male marten home ranges are mutually exclusive and
adjoi n one another so that all marten habitat in the
impounded area is inhabited (trapping likely affects this
assumption);
-Marten habi tat is defi ned as forest,and marten are
restricted to this habitat type;
- A 1:1 sex ratio exists in all age classes of the popula-
tion;
-65 percent of the population are juveniles (less than 1
year old)(R.Archibald 1982,Personal communication,
cited by Gipson et ale 1982),and juveniles appear in the
harvest in proportion to their number in the population;
and
-The mean home range size of male marten is 1685 acres
(682 ha)(Gipson et ale 1982).
This model gives an estimated density for all age/sex groups
of 0.0034 marten per acre (0.0085 per ha).Using a figure
of 11,798 ha of forest habi tat lost to impoundment areas,
borrow sites,construction si tes,and camps,habitat sup-
porti ng 100 marten (3.4 percent of the Susitna watershed
upstream from Gold Creek)would be lost.
P.Gipson (1982 Personal communication)attempted an inde-
pendent population estimate in July 1982 near Watana Creek
using a mark-recapture technique.A 6.8-miles (ll-km)
trapl i ne with trap spaci ng of 1312 feet (400 m)on either
side of Watana Creek captured no marten in 252 trap nights.
The minimum expected catch was ten,based on densities of
0.003 marten per acre (0.008/ha)and assumi ng all marten
within 1640 feet (500 m)of the trapline were captured.
This result suggests that fewer marten than calculated above
may actually exi st in the impoundment areas,and that fewer
marten would be affected.
E-3-441
4.3 -Impacts -Watana
There are obvious difficulties with the model.Perhaps the
most serious is that marten densities and home rallges vary
among different forest types.bei ng most common in dense.
mature coniferous forest (deVos 1952.Douglass et ale 1976.
Koehl er and Hornocker 1977).If only closed forest habitat
were used in the calculations (eliminating woodland and open
forest types).habitat supporting 26 marten (7.5 percent)
woul d be el imi nated from that currently supporting 347
marten.
Clearing of forested areas at construction sites and borrow
areas and the associated human disturbances may affect mar-
ten home range size and distribution.However.these types
of changes will be most extensive in areas affected by the
access route and transmission line and are discussed in Sec-
tions 4.3.3 and 4.3.4.
Lynx are uncommon in the Susitna Basin.probably because
thei r major prey.snowshoe hares.have been hi stori cally
uncommon.Habitat loss will probably eliminate the few lynx
occurri ng ,near the impoundment.
r~---,
Numbers of short-tailed and
reduced through habitat loss.
affected,1 ess than 5 percent
lost.
least weasels may also be
Based on the amount of area
of thei r popul at i on wi 11 be
Construct i on act iviti es and human di sturbance coul d result
in avoidance of the construction zone by furbearers.No
information is avai1able for lynx and weasels.Evidence
exists that marten are tolerant of moderate levels of
disturbance in areas adjacent to logging operations (Clark
and Cambell 1977.Soutiere 1978.Steventon and Major 1982).
(n)Raptors and Ravens
General types of potential impacts to raptors that occur
with development are summarized in Table E.3.158.The
construction and operation of the Watana dam will affect
raptors through a num~er of mechanisms (Table E.3.159).the
most important of whi ch are habitat loss and di sturbance.
Habitat loss includes the flooding of suitable nesting
cliffs.removal of trees used for nesting and perching,and
a loss of hunti ng areas.Many of the tree and cl i ff nests
wi thi n the impoundment area may be abandoned duri ng the
construction phase as a result of disturbance,and several
nest sites immediately adjacent to the access road or borrow
sites may also be abandoned.
E-3-442
4.3 -Impacts -Watana
,....
,....
(i)Habitat Loss
-Nesting Habitat
Nest i ng 1ocat ions fo r most cliff and tree-nest i n9
raptors are defined as a cliff or stand of trees
which may contain one or more nest sites.A pair of
raptors uses only one nesting location in a given
breedi ng season.However,a pai r may have one or
more alternative nesting locations.Nest sites are
defined as the actual nests or ledges on cliffs,or
the actual nests in trees used by a pair of raptors.
A pai r uses only one nest site ina gi ven breedi ng
season,but may have one or more alternate nest sites
at a nesting location.
The distribution,quantity,and quality of nesting
locations and nest sites clearly limits the numbers
and nest success of most raptors,including both
cliff-nesting and tree-nesting species (Newton 1979).
Cliff-nesters are especially limited by availability
of nesting locations and nest sites in many regions
because suitable nesting ~liffs (i.e.,those meeting
the specific nesting requirements of a species)are
fixed geologic features whose presence or absence are
a result of geologic events which are bound in geolo-
gi c time.In contrast,tree-nesters rely on vegeta-
tive features for nesting locations and nest sites.
Succession and growth of vegetation is on-going and
occurs relatively rapidly in contrast to formation of
cliffs,and therefore,tree-nesting locations and
nest sites are both lost and repl aced in much shorter
periods of time.However,for some tree-nesting
species (e.g.,bald eagles)the times required for
replacement may represent several generations of
birds,especially at northern latitudes.Because
raptors are one of the few groups of bi rds whose
distribution (within each species'breeding range),
numbers,and even nesting success are clearly limited
by the distribution,quantity,and quality of nesting
locations and nest sites,mitigation measures which
provide compensatory nesting locations and nest sites
can be particularly effective (see Appendix 3.1).
There is no reason to doubt that most raptors in the
Alaska Range are considerably more limited by nesting
1ocat ions and nest sites than by other parameters
such as food.Loss of nesting locations and nest
E-3-443
4.3 -Impacts -Watana
sites will almost certainly be the single most
important adverse impact of Susitna development to
raptors in the Susitna River drainage.However,a
distinction can be made between the prominent cliff-
nesters (i.e.,golden eagles,gyrfalcons)and the
prominent tree-nesters (i.e.,bald eagles,goshawks)
that serves to help identify the relative degrees to
whi ch the Susitna Hydroel ectri c proj ect wi 11 impact
populations of these two groups of raptors within the
Susitna River drainage.
For golden eagles and gyrfalcons (cliff-nesters),
most of the suitable nesting locations available in
the Susitna drainage are clearly concentrated in the
middle basin along the river and along the lower
reaches of its tributaries between Vee Canyon and
Devil Canyon.Despite the quantity of this habitat,
gyrfalcons are apparently not especially locally
numerous.The paucity of gyrfalcons,but the pre-
sence of a relatively larger number of golden eagles
is likely a result in large part of geography--the
area is near the southern limit of the gyrfalcons'
breeding range in south-central Alaska,but well
within the breeding range ofgol den eagles.In
contrast to the quantity and quality of cliff-nesting
habitat concentrated along the Susitna River between
Vee and Devil canyons,the occurrence of suitabl e
nesting locations for golden eagles is much lower
throughout the rema i nder of the mi ddl e and upper
Susitna basins (Bente 1982 Personal communication,
Roseneau 1982 Personal communication).Furthermore,
the density of suitable nesting locations for golden
eagles is probably relatively low throughout much of
the remainder of the Alaska Range (Bente 1981),and
regi onal topography further suggest s that concent ra-
tions of cliff-nesting habitat similar to that found
along the Susitna River in its middle basin are at
best uncommon.As a consequence,direct losses of
cliff-nesting locations in the middle basin as a
result of const ructi on of the Susitna Hyd roel ectri c
project are judged to be reasonably si gni fi cant to
the golden eagle population inhabiting the Susitna
River drainage.
In the case of bald eagles and goshawks (tree-
nesters),the majority of appropriate nesting habitat
containing suitable nesting locations and nest sites
cl early 1i es downstream of Devil Canyon.Upst ream of
Devil Canyon in the middle basin appropriate nesting
E-3-444
-
.....
-I
--
-
4.3 -Impacts -Watana
habitat for both species is sparse.Farther upstream
in the upper basin appropriate nesting habitat
becomes nearly non-existent.Pairs of both species
that nest throughout the Susitna River drainage
upstream of Devil Canyon are clearly members of much
larger downstream populations inhabiting the consid-
erably greater amounts of appropriate nesting habitat
found there.As a consequence,direct losses of bald
eagl e and goshawk nest i ng 1ocati ons in the mi ddl e
basin,as a result of construction of the Susitna
Hydroelectric project,are judged to be of reasonably
minor consequence to populations of those species •
Specific losses of known nesting locations of both
cliff-nesting and tree-nesting raptors and ravens are
discussed in greater detail below.The reader is.
reminded that numbers and percentages given below
represent known losses within the local vicinity of
the Susitna Hydroel ectri c project,and they shoul d
not be interpreted to necessarily represent the
degree to which total Susitna River drainage popula-
ti ons or regi onal popul ations of these speci es are
affected by the project.
Eighteen of 41 (44 percent)of the known raptor and
raven cliff-nesting locations and 4 of 10 (40 per-
cent)of the known raptor tree-nesting locations in
the general vicinity of the proposed project will be
lost as a result of the Watana development (Tabl es
£.3.160 and £.3.161).These include known nesting
locations for the following raptors:golden eagles,
bald eagles,gyrfalcons,goshawks,and ravens.
At least 6 (38 percent)of the 16 total known golden
eagle nesting locations in the general vicinity of
the project area wi 11.be di rectly lost to construc-
tion and filling of the Watana reservoir.Five of
those 6 nesting locations will be inundated,whereas
one may be lost during material excavation operations
at Borrow Site E (Figure £.3.115,Tables E.3.160,
E.3.161,andE.3.162).
Cliff-nesting habitat for golden eagles will become
severely limited upstream from the Watana damsite
once the impoundment is full.Loss of cl iffs up-
stream from the Watana damsite may increase the im-
portance of cliffs farther downstream in Devil
Canyon~along Fog Creek,Tsusena Creek,and other
streams drai ni ng into the Watana to Devil Canyon
E-3-445
4.3 -Impacts -Watana
reach.However s airspace is restricted in much of
Devil Canyons many of the cl i ff areas appear to be
exposed to higher levels of moisture s and existing
cliffs may lack suitable ledges on which golden
eagles could construct nests.
Golden eagles often have several alternative nesting
locations s some perhaps 4-5 miles (6-8 krn)apart
(McGahn 1968 s Roseneau et a1.1981)s and thus the 6
nests lost to the project do not represent 6 pairs of
eagles.The middle Susitna River basin population of
gol den eag1 es wi 11 probably be reduced by 3-5 pai rs
as a result of the construction and filling of the
Watana reservoir because of (1)losses of 38 percent
of the well-established golden eagle nesting loca-
tions along the river;(2)concomitant losses of most
of the other potential cliff nesting habitat upstream
from the Watana damsite;and (3)a suspected scarcity
of alternate nesting locations throughout much of the
remainder of the middle basin.
Four of 8 (50 percent)known bald eagle nesting 10ca-
ti ons in the general vi ci nity of the project area
will be lost to clearing and filling of the reservoir
(see Figure E.3.115 s Tables E.3.160 s E.3.161,and
E.3.162).Three of these locations are tree-nests
and one is the sole cliff-nesting location known to
be used by bald eagles in the Susitna River drainage.
(Bald eagle cliff-nesting locations are relatively
rare throughout Alaska north of the Alaska
Peni nsu1 a--for instances in the enti re Tanana River
drainage where over 40 nesting locations are known
[Roseneau et a1.1981]s only one nesting location is
on a cl iff.)Furthermore s almost all suitab1 e white
spruce and balsam poplar trees in the general
vicinity of Watana are located within the impoundment
area on tri butary deltas and i sl ands.Constructi on
and filling of Watana will likely limit bald eagles
to one or two available nesting locations along the
Susitna River upstream from the impoundment and one
or two potential locations along the lower Oshetna
River.This may increase the importance of other
potential nesting habitat downstream from the Watana
damsite s including balsam poplar stands along Portage
Creek and white spruce and balsam poplar near Stephan
Lake and along Prairie Creek.In any event,it
appears unlikely that habitat loss as a result of
construction and filling of the Watana reservoir will
have more than a local effect on the Susitna River
E-3-446
-
..-
-
-~
4.3 -Impacts -Watana
bald eagle population,the majority of which inhabits
the area downstream from Indian River (see Section
4.2.3[aJ)•
No known gyrfalcon nesting locations will be directly
lost as a result of the Watana project.However,
gyrfa1 cons often use nests constructed by other
cliff-nesting species,including ravens and golden
eagl es (Cade 1960,White and Cade 1971,Roseneau
1972),and some of the golden eagle and raven nesting
locations lost as a result of inundation or gravel
mini ng may represent past or future 1ocat ions used by
gyrfa1 cons.In south-central Alaska and the Al aska
Range,where nesting densities are low (Roseneau
1972,Bente 1981,Roseneau et ale 1981),use of other
species'nests by gyrfalcons is less prevalent than
in northern and western regi ons of the state where
the majority of the Alaska gyrfalcon population
breeds and winters (see Roseneau et a1.1981).It is
therefore unlikely that habitat loss as a result of
construction and filling of the Watana reservoir will
have more than minimal effect on the middle Susitna
River gyrfalcon population.
One of three (33 percent)known goshawk nesting loca-
tionsin the middle basin will be lost to clearing
and filling of the Watana reservoir (Figure E.3.115,
Tables E.3.160,E.3.161 and E.3.162).This nest
location is the only one discovered to date upstream
from the Watana damsite,beyond which typical goshawk
nest i ng habitat becomes very scarce (Roseneau 1982
Personal communication).
Eleven of 21 (52 percent)previously used raven nest-
ing locations in the middle basin will be lost as a
result of construction and filling of the Watana
reservoir (Figure E.3.115,Tables E.3.160,E.3.161
and E.3.162).Ten will be lost by inundation,and
one additional nest (R-4)may be inundated at times
of maximum flood stage (see Figure E.3.115)or be so
close to maximum operating water level as to be
unusab1 e.
Although a considerable number of raven nesting
locations and cliff habitat will be lost,the
consequences of thi sloss to ravens wi 11 be mi nor in
comparison to those for other cliff-nesting species
(particularly golden eagles).Ravens commonly nest
in a wide variety of situations in Alaska,including
E-3-447
4.3 -Impacts -Watana
man-made structures (Roseneau et a1.1981).Tree-
nesting in balsam poplar,aspen,and white spruce is
common,and ravens consistently nest on small cliffs
that are often unsuitable for raptors (Roseneau 1982
Personal communication).Construction and filling of
Watana without development of Devil Canyon is likely
to result in increased use of c1 iffs along Devil
Canyon and trees along the river and tributaries
downstream from the Watana damsite rather than a
reduction in the middle basin raven population.
- Hunting and Perching Habitat
In addition to loss of nesting habitat,it is
anticipated that some loss of perching and hunting
habitat for raptors will occur as a result of
const ruct i on and fill i ng of the Watana reservoi r.
Perching habitat will be lost primarily as a result
of inundation of cliffs (see Table E.3.159)and the
clearing of trees prior to reservoir inundation.
Most of these losses will occur concomitantly with
losses of nesting habitat.Losses of perches,
whether by inundation (cliffs and trees),materials
excavation (cliffs and trees),clearing (trees)or
b10wdown (trees),are considered of minor conse-
quence relative to losses of nesting locations.
Man-made structures,especially transmission towers
and smaller power poles,will also compensate in
part for losses of perchi ng habitat,because rap-
tors commonly use such structures as perches to
hunt from.
Loss of hunting habitat is more difficult to deter-
mine.No data were collected in the middle basin
to determi ne raptor hunti ng ranges and foragi ng
areas;however,losses of hunting habitat are
almost certainly to be of minor consequence,re1a-
t i ve to losses of nest i ng habitat.Most raptors
are limited by availability of nesting locations
and nest sites,not food (Newton 1979).Further-
more,raptor "hunting habitat"and productive areas
of prey habitat,including riparian zones and wet-
lands,are not necessarily equivalent.
Habitats such as riparian areas and wetl ands are,
of course,important because they tend to produce
and concentrate prey species.However,areas that
produce prey usually provi de escape cover for the
E-3-448
(~--
-
4.3 -Impacts -Watana
prey speci es that inhabit them.Some of the most
important hunting habitat for many raptors is often
overlooked because of confusion regarding nesting
location,nest-site limitations vs.food limita-
t ion,and because IIhunt i ng habitat II is commonly
assumed to be equi val ent to areas of ri ch prey
product i on.Some of the most important hunti ng
habitat for many raptors consists of the three
dimensional II gu lf ll of air over rivers,lakes,
unvegetated or little vegetated terrain,or over
forested valley floors in mountainous terrain.
Peregrine falcons provide an excellent example.
Peregri nes hunt and captu re much of thei r avi an
prey over water in front of and to the sides of
their river cliff-nesting locations as wetland,
forest,and shrubl and bi rds attempt to cross it.
Thus,some of the very best pereg ri ne nesting and
hunti ng habitat in the boreal zone is found only
along larger rivers (e.g.,Yukon,Tanana),regard-
less of varying and diverse prey habitats and
despite the fact that similar cliffs may be present
along narrow side tributaries.
For other species of raptors forest clearings,open
meadows and open mat-cushi on tundra serve ina
similar fashion as important hunting habitat.Most
raptors,and especially the larger species,have
the capability to range relatively long distances
from thei r nesting 1ocat ions to hu nt.Thus,loss
of hunting habitat as a result of construction and
operati on of the Susitna Hyd roel ectri c Project is
unlikely to be of major consequence to most raptors
i nhabiti ng the Susitna drainage.Loss of hunti ng
habitat wi 11 be compensated for in part by the
creation of the long,relatively narrow impoundment
over which potential prey species will pass.It is
also unlikely that loss of any prey production
habitat in the impoundment zone will be of a scale
that wi 11 be of major consequence to most raptors
inhabiting the middle and upper Susitna basins.
The general degree of impact may be inferred from
the data presented in Section 4.2.3(a);and addi-
tional information on hunting habitats of three of
the prominent species found in the middle basin
given below.
E-3-449
4.3 -Impacts -Watana
.Golden Eagles
Golden eagles probably hunt throughout the middle
and upper basins.However,they may avoid
heavil y treed areas,concent rati ng thei r effort
above and outside of the impoundment area rather
than in it.A tendency to hunt over open tree-
less areas,coupled with their varied diet that
i ncl udes several upl and speci es,suggests that
the loss of hunting habitat caused by the project
will have minor effects on golden eagles •
•Bald Eagles
Bald eagles may hunt throughout the middle basin;
however,they tend to spend greater amounts of
time at lower elevations near water bodies than
golden eagles.Losses of hunting habitat to bald
eagl es nest i ng in the mi ddl e bas in may therefore
be greater than losses to gol den eagl es.How-
ever,some attraction of waterfowl to open water
behi nd the dam or in the ri ver downstream of it
in early spring may compensate in part for some
losses.Open water downstream from the Watana
dam may provide important wintering habitat from
the Watana dam in an area in which none currently
exists.At least a few bald eagles have over-
wintered in similar habitat along the Tanana
River in mild winters (Ritche 1974).However,
the Watana impoundment,wi th its 1arge drawdown
and consequent lack of aquatic vegetation,is not
anticipated to be particularly attractive to
waterbirds as feeding habitat.On the other
hand,bald eagles in the middle basin are almost
certainly more limited by availability of nesting
habitat than by avail abil ity of food.Assuming
water fowl are never attracted to the impound-
ment,and that fi sheri es never develop there,
surrounding habitat,including tributaries and
water bodies near the impoundment zone,is likely
to be adequate for those eagles that remain after
construction and filling of the Watana
reservoi r•
•Gyrfal cons
Gyrfal cons may al so hunt throughout the middl e
basin,but they tend to avoid wooded areas and
probably concentrate their effort well above the
E-3-450
4.3 -Impacts -Watana
impoundment zone.Thei r tendency to hunt in
open,treel ess areas incl udi ng the al pi ne zone,
coupled with their opportunistic nature,suggests
that the loss of hunt i ng habitat as a result of
construct i on and fi 11 i ng of the Watana reservoi r
will not be a serious impact.
'""'
,...
I"""
I
....
....,
....
(i i )Disturbance
Bal d eagl es and gol den eagl es are specifi cally pro-
tected under the U.S.Bal d Eagl e Protecti on Act of
1940 (as subsequently amended).A part of this act
prohibits the "taking"of any bald or golden eagles,
parts thereof,or the nests or eggs of such bi rds
without a permit."Take"is defined to include
molest or disturb.
The act does not authorize the taking of bald eagle
nests whi ch interfere with resource development or
recovery operations.Take may only occur for scien-
tific or educational purposes at the discretion of
the Regional Director (USFWS).Recently an amendment
to the Bal d Eagl e Protecti on Act was drafted (16
U.S.C.668a)that allows golden eagle nests to be
'taken if they interfere with resource development or
recovery operations.However,regulations pertaining
to this amendment are not yet available.Clearly,
the taking of eagle nests as a result of the project
must be addressed and mutually agreed to in consulta-
tion with the Al aska Regi ona 1 Di rector of the USFWS
before the project can be built.Such consultation
was initiated on February 1,1983,in a letter from
the Alaska Power Authority,to K.Schreiner,USFWS
Area Director,Alaska.
In addition,there are state laws that provide
simil ar protecti on for these and other raptor
speci es.The Al aska Department of Fi sh and Game has
al so developed gui del i nes to protect raptor nests
from destruction or disturbance.
Roseneau et ale (1981)reviewed and summarized most
of the i nformat i on on ki nds and effects of di sturb-
ance to raptors.Most information is anecdotal.
Responses of raptors to various types of disturbance
are compl ex--several factors may affect the sensi-
tivity of raptors to disturbance (Table E.3.163)•
Timing of the disturbance is an important factor
E-3-451
4.3 -Impacts -Watana
(Table E.3.164),and effects of disturbance may be
additive.
Responses of raptors to di sturbance and the effects
of these responses are often highly variable.In
many cases,nesting raptors have shown a surprising
degree of tolerance and habituation to disturbances;
yet in other cases,the same types and 1evel s of
disturbance have had detrimental effects (Roseneau
et ale 1981).In general,a mounting body of
evidence suggests that raptors will habituate to and
tolerate at least moderate forms of disturbance.The
same body of evidence suggests that the most
detrimental forms of disturbance are those that occur
within territorial defense zones (i.e.,nesting
locations).Prolonged disturbances,multiple
disturbances,and direct overt harassment from either
the ground or the ai r are particularly harmful.
Some species of raptors appear to be less tolerant of
disturbance than others.Of species in Alaska,
golden eagles appear to be the most sensitive,
especially to aircraft disturbance and human presence
(see Roseneau et al.1981).Although gol den eagl es,
like most raptor species,are reluctant to flush from
nests as a resul t of ai rcraft passage duri ng
i ncubat ion,they often 1eave thei r nests we 11 in
advance of approaching ai rcraft during the nestl ing
period (Roseneau et ale 1981).Furthermore,they
often leave their nesting areas quickly when people
approach,often at considerable distances (e.g.,as
much as 0.5 mil es (0.8 km);Roseneau Personal
communication)from the nest.Several documented
nesting failures of golden eagles in some areas have
been bl amed on human interference (Roseneau et al.
1981).
Nesting locations of raptors and ravens that may be
subject to disturbance by the construction and
filling of the Watana reservoir are listed in Table
E.3.162.Nesting locations were selected for
inclusion on the basis of distance from project
act ions.Judgments as to the general 1evel of
disturbance were made on the basis of nest elevation
above potential disturbance,distance to the
disturbance,and general nature and scale of the
disturbance,assuming year-round activity (clearing,
material excavation and dam construction).
E-3-452
I""",
!
r0-
t
I
I
....
....,
4.3 -Impacts -Watana
Seven golden eagle nesting locations within or on the
edges of the Watana impoundment may be susceptible to
disturbance from reservoir clearing operations (see
Figure E.3.II5 and Table E.3.I62:the exceptions are
GE-7 and GE-IO).Five of those locations will be
inundated later.Two of the five locations will also
be susceptible to considerable disturbance from
ma~erial excavation at Watana Borrow Site J (see
Table E.3.I62;however,both locations (GE-8 and
GE-9)will be inundated.Anei ghth golden eagle
nesting location (GE-ll)will probably be physically
destroyed by material excavation unless some action
is taken to specifically preserve it (e.g.,the
establishment of a buffer zone limiting excavation to
areas outside a radius of at least 300 feet from the
nest cl iff).
Four bald eagle nesting locations within the Watana
impoundment are susceptible to disturbance from
reservoir clearing operations (see Figure E.3.1I5 and
Table E.3.I62:the exceptions are BE-I and BE-6).
At 1east two of the four 1ocat ions are tree-nests
that will eventually be flooded (BE-3 and BE-5),and
one is a cliff nest that will eventually be inundated
(BE-4).The fourth location (BE-2)is also likely to
be inundated or may be lost because of shore 1 i ne
erosion unless specifiC safeguards are taken.
No known gyrfalcon nesting locations appear suscept-
"ible to major disturbance from Watana construction;
however,one location (GYR-I)may be susceptible to
some disturbance during reservoir clearing.
At least one known goshawk nesting location will be
susceptible to disturbance from reservoir clearing
(GOS-I);this nest will eventually be inundated
(Figure E.3.115).A second nesting location (GOS-2)
is located in the Devil Canyon reservoir,but may be
susceptible to some disturbance as a result of mate-
rial excavation at Watana Borrow Site I (see Table
E.3.I62)•
Twelve common raven nesting locations within or on
the edges of the Watana impoundment may be suscep-
tible to di sturbance from reservoi r cl eari ng opera-
tions,but as many as 11 of them will eventually be
inundated (see Figure E.3.II5 and Table E.3.I62:the
exception is R-I).Three of the locations (R-9,R-IO
and R-ll)that will eventually be inundated will also
E-3-453
4.3 -Impacts -Watana
be susceptible to considerable disturbance associated
with material excavation at Watana Borrow Site J (see
Table E.3.162).Two other nesting locations (R-14
and R-lS)are located downstream from the Watana dam-
site,but they may be susceptible to considerable
disturbance during excavation of materials from
Watana Borrow Site H.(This site will probably not
be mined.)
(0)Waterbirds
Because of the low numbers of waterbi rds in the Susitna
Basin (Section 4.2.3[bJ),impacts from the Watana develop-
ment will not have a major effect on regional populations.
Waterbirds of the basin will be affected during construction
of the Watana development by loss of habitat,alteration of
habitat and disturbance.
(i)Habitat Loss
Loons,grebes,swans,and several duck species in the
Susitna Basin occur primarily on lakes (Appendix 3E).
Most species will not be affected seriously by loss
of habitat since only 94 acres (38 hal of lakes (0.2
percent of total in Gold Creek and Watana watersheds)
of 1akes wi 11 be flooded by the Watana impoundment.
However t some species will suffer a permanent loss of
breeding habitat in fluviatile shorelines and
alluvia:harlequin duck,common merganser,semi-
palmated plover,spotted sandpiper,wandering
tattler,and arctic tern.Common goldeneyes and
mergansers wi 11 lose nesti ng trees duri ng reservoi r
clearing.Mergansers will nest on banks and other
locations in the absence of cavities.Goldeneyes
prefer to nest in relatively large diameter cavities.
Prince (1968)reported the smallest cavity diameter
in his study of common goldeneyes to be 6 inches
(IS.2 cm).Most 1arge trees are on the lower slopes
of the Sus itna Vall ey and wi 11 be fl ooded.Open
water in fast-flowing streams and in the main
channel itsel f provides wi nter habitat for the di pper
of which a significant portion may be lost.
During filling,the sandbars,islands,and shorelines
used by shorebi rds will be flooded.Two breed i ng
species (spotted sandpiper,and semipalmated plover)
and about seven migrant species will be affected.
The Susitna River does not support many migrant
shorebirds and the loss of habitat for migrants will
E-3-454
4.3 -Impacts -Watana
not be serious.However,all of the shorebird breed-
ing habitat in the impoundment area will be lost.
..-
.....
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r
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(i i)Habitat Alteration
During construction and filling,habitat alteration
will occur primarily from clearing and flooding of
shorelines.Clearing of forest will have little
effect on waterbird habitats with the possible excep-
tion,as noted in the previous section,of cutting
nest trees.Flooding will probably affect harlequin
ducks and fish-eating common and red-breasted
mergansers through some loss of food resources.
Mainstream fish populations downstream are not
expected to be seriously affected by flooding,but
port ions of the grayl i ng popul ati ons in tri butary
streams may be lost (Section 2.3).Nevertheless,
fish popul ati ons above impoundment 1evel wi 11
probably remain sufficient to support the low
merganser numbers in the area,and this impact will
not be measureable •
Waterbi rds in tundra areas have been shown to avoi d
immediate areas of intense human activity (Barry and
Spencer 1976).Similar avoidance may occur in other
areas of open wetland.Clearing of the impoundment
area,especially near the river and its tributaries
and near wetlands and lakes,will be the most serious
disturbance factor for most waterbirds.Clearing and
E-3-455
4.3 -Impacts -Watana
associated heavy machinery traffic will physically
destroy nests of some speci es if conducted between
May and Jul y.Di sturbance will be intense duri ng
clearing operations,and many species will be
affected.
Results of studies of the effects of aircraft distur-
bance on ducks (Gollop et aT.1974,Schwei nsburg
1974,Schwei nsburg et al.1974,Ward and Sharp 1974)
have found changes in behavior,but little short-term
effect on distribution of nesting or moulting ducks.
Except at Stephan Lake,geese and whi stl i ng swans
occur in only small numbers during migration in the
Susitna area and are unl i kely to be much affected by
disturbance.Trumpeter swans nest in the middle
basin;however,Kessel et al (1982a)report only one
nest in the Fog Lakes area.Two other swan nests
have been reported in the development area by R.
Fleming (1983 pres.comm.);one on the east fork of
Wakana Creek and are on the North Fork of the
Talkeetna River approximately 5-10 miles downstream
from the confluence with Prairie Creek.Other nests
may occur in the area,although the majority of the
basin population nests well to the east of the pro-
ject area,and only small numbers occur in the Watana
area during migration.Trumpeter swans are known to
be sens it i ve to di stu rbance duri ng the nest i ng and
fledgling periods and any nests which occur in the
project area would be adversely affected by even
casual human intrusion (Hansen et al.1971).Geese
do not nest in the basi n and are uncommon duri ng
migration;they are unlikely to be seriously affected
by disturbance.
(p)Other Birds
(i)Construction
Terrestri al bi rds wi 11 be most affected duri ng con-
struction by habitat loss through cleari ng of the
impoundment area,access roads,camps,borrow pits,
and other facilities.Clearing of the impoundment
area will affect the largest number of birds and will
result in changes in the distribution and relative
abundance of speci es in the area.Forest speci es
will be replaced by birds of shrub and open habitats.
Artificial habitats will be created for those species
which wi 11 use them.Another impact to bi rds near
E-3-456
....
.....
.....
4.3 -Impacts -Watana
construct i on zones is sensory di sturbance from
traffic,noise,dust,and people.
-Habitat Loss
Proportionate losses of various vegetation types to
the Watana project are presented in Table E.3.82.
The most severely affected vegetation types will be
forest types;in particular,open birch,closed
birch,and closed balsam poplar forest types.Open
and closed mixed conifer-deciduous forests,open
spruce forests,and woodl and spruce forests wi 11
also be severely affected.The 12 census plots
studied by Kessel et al.(1982a)represent an over-
view of the terrestrial avian habitat types present
in the middle basin.The bird census study plots,
their avian habitat equivalents (as provided by
Kesse 1 et a 1.1982a),and app rox imate vegetat i on
type equivalents are presented in Table E.3.139.
Table E.3.165 presents the proportionate loss of
vegetation type equivalents to the avian habitats
represented in the census plots resul ti ng from the
Watana proj ect.
Habitat is a vague concept whi ch attempts to pro-
vide biologically meaningful explanations of where
animal s are found.Because habitat compri ses both
biotic and abiotic factors,habitat suitability for
a given species and vegetation type (i.e.,Viereck
and Dyrness cl assifi cati ons)can be expected to be
imperfectl y correl ated.Attempts have been made
(through Principal Components Analysis,and related
Ordination techniques)to define "habitat"for
individual species by measuring numerous biotic
and/or abiotic variables and correlating derived
abstract factors with the distribution and use
patterns of each species.Although such analyses
are of great theoretical interest,they generally
fail to provide the kind of information required
for an assessment of impacts.
Although they are a crude approximation to actual
avi an habitat,the loss of vegetati on types pro-
vides the only available measure of the impacts of
the Susitna project on most terrestrial avian
species.Kessel et ale (1982a)provide 2 cautions
in the use of Viereck and Dyrness vegetation types
as avian habitats:(l)Viereck and Dyrness "tall
shrubland"supports two more or less distinct avian
E-3-457
4.3 -Impacts -Watana
communities (medi urn and tall shrub bi rds of Kessel
[1979J),and (2)Viereck and Dyrness closed coni-
ferous and deciduous forests (with a minimum of 75
percent closed canopy cover)are not restricted
enough for true coniferous or deciduous forest bird
communities (which require at least 90 percent
coniferous or deciduous components in the canopy,
according to Kessel et ale 1982a).If this is the
case,loss of 0.4 percent of the combined Gold
Creek and Watana watersheds tall shrub vegetati on
will affect two avian communities,medium shrub
birds and tall shrub birds (see Table E.3.140).
Also,loss of mixed conifer-deciduous forest may
underestimate loss to the mixed conifer-deciduous
forest bird community while loss of coniferous
forests and deciduous forest may overestimate the
loss to the coniferous forest and deciduous forest
bird communities (see Table E.3.140).
As shown in Table E.3.165,with the exception of
low mixed shrub,proportional losses are greater
for the most densely occupi ed vegetat i on types.
Although much overlap in species use of vegetation
types occurs,species restricted primarily to deci-
duous and mixed forests will be most severely
affected.These i ncl ude spruce grouse,hai ry and
downy woodpeckers,alder flycatcher,blackcapped
and boreal chickadees,brown creeper,varied,
hermit and Swa i nson I s thrushes,yell ow-rumped and
blackpoll warblers,northern waterthrush,and
dark-eyed junco.
Kessel (unpubl ished tables)provided an estimate of
numbers of breeding bi rds of each speci es lost
based on 1981 density data and general observations
in the project area.These estimates,in Table
E.3.166,are considered approximate order-of-
magnitude figures.The total loss of breeding
bi rds of these species is 82,500 for the Wakana
facility alone,4 percent of the total population
within 16 km of the Susitna River between the
McLaren River and Gold Creek.Largest numerical
losses will be for species which occur in high den-
sities in a range of vegetation types and include
Swainson1s thrushes,ruby-crowned kinglets,yellow-
rumped warblers,Wilson1s warblers,dark-eyed
juncos,and tree sparrows.However,most of these
speci es are abundant throug hout the middl e bas in.
The highest proportional losses will occur to
E-3-458
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i
I
4.1 -Impacts -Watana
.species restricted to these vegetation types which
suffer the highest proportional losses and include
spruce grouse,hai ry woodpecker,boreal chi ckadee,
brown creeper,and northern waterthrush.
-Habitat Alteration
Habitat alteration resulting from clearing and con-
struction of buildings,dams,and borrow sites will
have negative effects on some species and positive
effects on others.For speci es whi ch are
restricted to forest habitats,deve1 opment-re1 ated
alteration will represent effective habitat loss
(see above discussion).Species found in closed
forests will be reduced in numbers near those
c1 eari ngs whi ch are in forested habitat.Areas to
be affected by temporary facilities and borrow
sites are relatively small,discrete areas and with
or without reclamation will eventually result in
openings of early successional habitats.Species
associ ated wi th edges and di sturbed or artifi ci a1
habitats will increase in these areas.Clearing of
forest vegetation may increase bird species diver-
sity through the creation of a different habitat
.type and associ ated edge effects,depend i ng on the
size of the c1 eari ng (Anderson et a1.1977).How-
ever,some researchers have found no true edge
effect (Kroodma 1982),and others have found a
decrease in diversity (Anderson 1979)because of
transmission line clearing through forested areas.
Since forest vegetation in the Susitna basin sup-
ports a somewhat hi gher di versity of bi rds than
shrub vegetation (Table L3.l38),there may be a
decrease in bird diversity as the result of forest
clearing.
Some species are capable of utilizing artificial
habitats created by man and these species may bene-
fit from certai n habitat changes.For examp1 e,
bank swallows and ki ngfi shers may dig thei r nest
cavities in sand walls of borrow sites that are not
in active use or even in less disturbed areas of
large sites that are in active use.Cliff swallows
readily nest on buildings.Ravens and gulls will
feed at refuse dumps if these are not properly
maintained.
E-3-459
4-3 -Impacts -Watana
-Disturbance
Di sturbance to terrest ri a1 bi rds will resu 1t pri-
marily from road traffic and is discussed in
Section 4.3.3(c).Some disturbance may also result
from activiti es of peopl e at borrow sites and the
construction site,but there is little quantitative
information about the effects of such disturbance.
Local di sturbance of thi s nature will not have any
serious effect on overall populations of terres-
trial birds.
(ii)Filling
Si nce the reservoi r is to be cl eared,most of the
habitat loss associated with the Susitna project will
occur during the construction phase and was discussed
above.During filling,the species that will be
affected are those that had invaded the cutover area
(mainly birds of shrub habitats)and birds dependent
on shorelines,mudbars,and streams.These latter
species are primarily shorebirds and the dipper.
Dippers inhabit fast-running streams;dipper breeding
and feedi ng habitat will be lost to the extent that
the lower reaches of such streams are flooded (see
Chapter 2).Dippers also winter in the Susitna River
drainage along open-water of fast-running streams,
including the Susitna River itself.Open water in
wi nter at the dam intake zone is not expected to
serve as di pper habitat.Loss of open water in
wi nter throughout the impoundment zone wi 11 excl ude
di ppers from wi nteri ng there.However,the 1arge
open-water reach below the dam in winter should
compensate for the loss of dipper wintering habitat
above the damsite.
(iii)Operation
The abundance and species composition of birds along
the downstream reaches of the river will change as
new riparian vegetation invades areas of the flood-
pl ai n and proceeds through the successi onal stages
described in Section 3.3.1.These changes will be
most vi si bl e in the reaches upstream from Talkeetna
where alteration of vegetation will be most pro-
nounced.Because bi rd densities and species diver-
sities are highest in tall shrub and mature forest
stands,the vegetation changes over 100-200 years
could be considered beneficial to terrestrial
E-3-460
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4-3 -Impacts -Watana
breeding birds.However t the proportionate changes
in speci es abundance in the study area as a whole
will be very small during the license period.
(q)No n-game (Sma 11)Mamma 1s
Population densities of most species of small rodents fluc-
tuate widely under natural circumstances (Krebs and Myers
1974 t Kessel et a1.1982a);it is consequently difficult to
predict postconstruction population levels.Although the
populations of some species will be diminished because of
the project t most species respond quickly to disturbance,
abandoning some areas and colonizing new ones.In addition t
reproductive rates of small mammals are high,and most popu-
lations can recover quickly from population reductions if
sufficient food resources and space are available •
Only those species of small mammals that are restricted to
forest habitats are expected to show marked decreases,pri-
marily because of loss of forest to the impoundment and con-
struction sites.These decreases may,in turn,be reflected
in changes in behavior and/or population levels of certain
carnivore or raptor species that depend on small mammals for
prey.
During the construction phase,small mammals will mainly be
affected by the clearing of the impoundment area,the borrow
sites and the construction camp.About 26,730 acres
(10,818 hal of forest will be cleared.The species that are
restricted to forest habitats and will thus be most affected
are porcupines,snowshoe hares,pygmy shrews t and red
squirrels.Small numbers of hares and porcupines and
extremely small numbers of pygmy shrews were observed in the
project area.Because the area does not seem to be prime
habitat for the former two species (Kessel et ale 1982a),
thei r regi onal dens i ti es are not expected to be affected by
the project.Red squirrels are common throughout the
forested areas of the project area.About 3.5 percent of
their preferred spruce habitat in the middle and upper qasin
will be cleared.
The other speci es that wi 11 be affected by cl eari ng duri ng
Watana construction will be the northern red-backed vole •
Red-backed voles were found in nearly every habitat type in
the Watana area,but were most common in spruce and cotton-
wood forests.A decrease of up to 5 percent in the overall
abundance of this species is expected.
E-3-461
4-3 -Impacts -Devil Canyon
Duri ng the three-year fi 11 i ng stage,many of the areas
cleared during construction will be colonized by early
successional plant species and small mammals.Meadow voles
are expected to thrive in such areas (Dabbs et a1.1974).
Tundra voles,masked shrews,and arctic shrews may also
recolonize these areas.As water levels rise during the
f"illing stage,these populations of small mammals will be
displaced.However,no substantial reductions in regional
populations are expected as a result of these effects.
The major impact on small mammals during the operation phase
of Watana Dam wi 11 be the changes caused by succession of
disturbed areas,such as the borrow sites and camps,and of
the newly exposed land downstream from the dam.Species
that occur in grasslands and early successional communities
will be favored initially.These include meadow voles,and
in some cases,tundra voles,masked shrews,and arctic
shrews.As succession progresses to shrub1ands,the habitat
will improve for speci es such as northern red-backed vol es
and masked shrews.
4.3.2 -Devil Canyon Development
(a)Moose
Because of steep topography and extensive mature forests in
the Devil Canyon area,fewer moose occur in this portion of
the Susitna Basin than in the area to the east of Watana
Creek (ADF&G 1982a).Distributions of moose observed during
surveys in March 1981 suggest that moose were not common in
the vi ci nity of the Devil Canyon dams ite but became more
abundant in upstream areas near the Watana damsite.ADF&G
(1982a)estimated that 30 moose were present wi thi n the
Devil Canyon impoundment area during a census in late March
1981.The snow depth recorded at Devil Canyon at that time
was 29 inches;thi s census underestimates the number of
moose that would be present during winters with deeper
snows.
Because of the low numbers of moose in the Devil Canyon
area,impacts on moose in this region will be of smaller
magnitude than in the Watana development area.The range of
impacts to moose that may result from the Devil Canyon pro-
ject are similar to those already discussed for the Watana
project.Potential impacts include loss of habitat,alter-
ation of habitat,interference with seasonal movements,
mechanical and human disturbance,hazards associated with
the drawdown zone,and hunting mortality.Impacts
E-3-462
;r.--'
4-3 -Impacts -Devil Canyon
associated with the access roads,the railway and transmis-
sion lines are discussed in Sections 4.3.3 and 4.3.4.
.....
.-
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(i )Construction
Construction of the Devil Canyon dam will involve
intense construction activity at the actual damsite,
establishment of a temporary camp,removal of forest
cover in the impoundment,and the excavation and
transportation of borrow material.The most impor-
tant effects of construction on moose will be habitat
loss,direct mortality,interference with seasonal
movements,and disturbance.
As di scussed for the Watana project,alteration of
habitat resulting from construction activities will
be minimal and effects on moose will be negligible.
-Habitat Loss
An estimated 7907 acres (32 km 2 )will be cleared
withi n the Devi 1 Canyon impoundment area and an
additional 529 acres (214 ha)will be used for
operational areas,campsites and borrow sites.
Losses of major forest cover types in relation to
their availability indicate that the greatest pro-
portion of losses will occur in woodland spruce,
open spruce,and mixed forest cover types (Table
E.3.83).Because moose in the Susitna Basin were
most commonly relocated in spruce forest than in
any other forest cover type (ADF&G 1982a),the loss
of spruce habitat in the vicinity of Devil Canyon
may be important to moose.However,the limited
area of bottomland habitats and the steep slopes of
the Susitna River valley in the Devil Canyon area
probably limit present use by moose.Although
almost all of the low elevation habitat will be
lost,moose do not appear to commonly winter in the
Devil Canyon area,and the loss of low elevation
.habitats probably will not appreciably alter over-
winter survival of moose in the Devil Canyon area.
-Interference with Movements
The Devi 1 Canyon impoundment generally wi 11 not
exceed 1 mile (1.6 km)in width.Clearing of vege-
tation in the impoundment area may present a visual
barrier to moose movements,and disturbances asso-
ci ated with cl eari ng operations and constructi on
E-3-463
4-3 -Impacts -Devil Canyon
could block or alter migration paths across or
along the river.Moose relocations in the Devil
Canyon area suggest that no major movement corri-
dors for moose exist within the Devil Canyon
impoundment area,but more frequent crossings may
occur once the Watana impoundment is present.
-Di sturbance
Effects of disturbance on moose in the Devil Canyon
area will be minimal and will be similar to those
impacts discussed for the Watana project.
-Mortality
Although a few moose may be killed as a result of
collisions with vehicles or other accidents associ-
ated wi th constructi on areas,the effect of those
mortalities on moose populations will be negli-
gible.(Access road mortality is treated ;n
Section 4.3.3.)The major mortality factor asso-
ciated with the constructi on of the Devil Canyon
dam will be the probable increase in hunting asso-
ciated with the influx of construction workers and
other personnel to a previ ously remote area.
Because moose will be more abundant in the Watana
area than in the Devi 1 Canyon area,hunting acti-
vity by Devil Canyon personnel wi 11 1ikely be con-
centrated to the east of the project area.Effects
of hunting on moose are described in more detail
for the two development areas in Section 4.3.3(a).
(ii)Filling and Operation
The fill i ng phase of the Devil Canyon impoundment is
estimated to be approximately 2 months (as opposed to
3-4 years for the Watana project).In addition,the
drawdown zone (to 50 ft [15 m]in some years during
August and September)wi 11 be 1 ess than 3 ft (1 m)
for most of the year.Because of the small er area,
local topography,the small drawdown zone during most
of the year,and the rapid filling sequence,the
effects of the Devil Canyon project on moose will be
much 1ess severe than those of the Watana project.
The major impacts to moose wil 1 be alterati on of
habitat,loss of habitat,blockage of movements,
direct mortality,and disturbance.
E-3-464
-
-
-
-
-
~,
4-3 -Impacts -Devil Canyon
-Alteration of Habitat
As discussed for the Watana project,the Devil
Canyon impoundment wi 11 cause some a1terati ons of
vegetation in the vicinity of the impoundment and
in areas downstream from the dam.
Alteration of vegetation in the vicinity of the
impoundment may occur as a result of several micro-
climatic changes such as seasonal temperatures,
wi nd di rect i on and speed,and ice fog.Effects of
these changes on moose wi 11 probably be undetec-
table (Section 4.3.1[a]).
Alteration of vegetation downstream from the Devil
Canyon site,however,may affect the distribution,
abundance,and qual ity of moose habitat.The com-
bi ned effects of the Watana and Devi 1 Canyon dams
will result in increased water temperatures in
downstream portions of the river,and it is antici-
pated that with both dams the Sus itna Ri ver wi 11
remain open in winter from the Devil Canyon dam to
Talkeetna.Flow regimes following completion of
the Devi 1 Canyon dam are not expected to di ffer
greatly from flow regimes of the Watana project.
Hence,no additional differences in vegetation
resulting from lower water flows are expected when
the Devil Canyon dam becomes operational.
Open water in the Devil Canyon-Talkeetna reach of
the Susitna River will affect vegetation in several
ways.Steam fog will be common over the open water
reach duri ng wi nter.Because of the hi gh moi sture
content of the air,icing of vegetation along the
river will occur.However,the area of riparian
habitat that wi 11 be affected depends on several
topographi cal and c1 imati c factors,and cannot be
accurately predicted.It is also not known whether
p1 ant productivity will be detrimentally affected
by icing or whether moose will utilize iced winter
browse.Although it is probable the icing of vege-
tation will not make browse unavailable,it will
increase energy requirements of those individuals
that consume large quantities of ice.As a result,
impacts on moose associ ated with vegetation i ci ng
along the Devil Canyon-Tal keetna porti on of the
Susitna River are difficult to quantify.
Because of the open-water conditions in the Devil
Canyon-Talkeetna reach,ice scouring of lower level
E-3-465
4-3 -Impacts -Devi 1 Canyon
riparian areas will be eliminated.Annual distur-
bance of successional growth in these areas will be
reduced (flooding will still scour some areas),and
the vegetation will begin to colonize the unvege-
tated band resulting from ice scouring during
operation of Watana only.
Riparian communities on higher ground of the river
channel wi 11 gradually succeed to cottonwood
forest,but at the same time will extend downward
into the newly exposed areas of the river channel.
Browse will increase in abundance along the river
once Devil Canyon is commissioned.However,such
browse may be partially unavailable,as described
in the following section,or of reduced value due
to icing,as described above.
-Interference with Movements
Movements of moose in the vi ci nity of the Devil
Canyon impoundment and downstream from the dam may
be affected by the Devi 1 Canyon project.Moose
attempt i ng to c ross the impoundment area may be
inhibited by visual factors such as the I-mile
(1.6-km)wi de impoundment or the presence of open
water areas in wi nter.The width of the impound-
ment is not likely to present a physical barrier to
moose in summer,but winter open-water areas could
deflect movements.
Moose in the Devil Canyon-Tal keetna reach of the
Susitna River overwi nter in riparian habitats and
on river i sl ands of the Susitna Ri ver (ADF &G
1982b).Parturient cows apparently prefer to calve
on river i sl ands or in riparian areas,presumably
because of the availability of high quality forage
and reduced numbers of predators (Stringham 1974).
The presence of open water between the dam and
Talkeetna may interfere with use of these river
island habitats during the winter and the early
portion of the calving period.Moose in northern
British Columbia are not known to cross sections of
open water downst ream from dams du ri ng wi nter (F.
Harper 1982 personal communi cati on).The effects
of exposure to sub-zero temperatures following
crossing of open water would presumably physiologi-
cally stress moose during a period when their
energy balance is already precarious.Browse and
cover occurring on islands must,therefore,be
E-3-466
.-
--4-3 -Impacts -Devil Canyon
considered unavailable to moose for at least 3-5
months during winter.
-Di stu rbance
Mechanical and human disturbance should decline in
the Devil Canyon area once the dam becomes opera-
tional.Increased public access will maintain dis-
turbance at a higher level than is currently en-
countered,but at a 1evel much lower than duri ng
construction.If animals are not directly
harassed,disturbances during the filling and
operation stages will at most have a slight effect
on moose distributions.
-Mortality
During the filling and operation of the Devil
Canyon dam,moose mortality may increas.e as a re-
sult of hunting and accidental deaths (see Section
4.3.l[aJ).
(b)Cari bou
......
.....
(c)
Few impacts of the Devi 1 Canyon development on caribou are
expected.The impoundment area,particularly the area near
the damsite,has been infrequently used by caribou either
historically or in recent years.A small portion of the
Nel china herd may occasionally cross the impoundment,but
because the crossing hazards are expected to be less severe
than those associ ated wi th the Watana impoundment,fewer
subtantial impacts are expected.There may be some impacts
on caribou resulting from aircraft disturbance and the
Watana to Devi 1 Canyon road segment--these wi 11 be simi 1ar
to those associated with the Watana development,and are
discussed in Sections 4.3.1(b)and 4.3.3(b).
Dall Sheep
The construction,filling and operation of the Devil Canyon
dam wi 11 have no di rect impact on any of the three Da 11
sheep populations in the middle Susitna Basin.All three
populations are far removed from the damsite.
Any increase in air traffic to the Watana airstrip caused by
the construction of the Devil Canyon dam has the potential
for disturbing the Mt.Watana-Grebe Mt.population (coming
from the south)or the Portage-Tsusena Creek popul at ion
E-3-467
4-3 -Impacts -Devil Canyon
(coming from the north).The effects of aircraft traffic on
Da11 sheep are discussed in Section 4.3.1{c).
(d)Brown Bear
The impacts of the construction of the Devil Canyon dam on
brown bears will be similar to those during construction of
the Watana dam,except that the number of bears affected
will be much smaller.The area near the Devil Canyon site
is at lower e1 evations and is not prime habitat for brown
bears.
Steep canyon walls will confine most of the Devil Canyon
impoundment,thus minimizing the area inundated.There will
be some loss of riparian areas,with their associated food
sources -berries,early spring vegetation,and moose
calves.No potential denning areas will be affected.Other
10ng-term effects of the Devil Canyon development,such as
increased hunting and aircraft disturbance,will be similar
to those associ ated with the Watana development.but at a
reduced sca1 e.
Some human/bear contact is likely to occur during the con-
struction of the dam,leading to increased bear mortality.
As discussed in Section 4.3.1{d),improper food and garbage
handling practices will increase problems with bears.
Avoidance of areas of human activity by bears wi 11 cause
some habitat loss,resulting in a lower carrying capacity
for brown bears.
(e)Black Bears
The impacts of the Devil Canyon development on the local
black bear population will be substantially less than those
for Watana,because only a small portion of acceptable black
bear habitat in the Gold Creek watershed will be lost.The
impact on denning areas will also be considerably less;only
one of 16 den sites (6 percent)found in the vicinity of the
Devil Canyon impoundment will be flooded.Most of the
potential impacts discussed for the Watana development will
exi st,but at a much-reduced 1eve1.Downstream effects of
the Devi 1 Canyon impoundment shou1 d be the same as those
discussed in Section 4.3.1(e).
(f)Wolf
Impacts from the Devil Canyon development will be very Slml-
1ar to those from the Watana development.No known dens or
rendezvous sites will be affected,and the loss of potential
E-3-468
r
4-3 -Impacts -Devil Canyon
den sites is not expected to have significant effects on the
wolf populations.Similarly,disturbance is not expected to
affect wolves except possibly at den sites during May and
June.Wolf pups moved from dens because of disturbance when
they are very young may not survive (ADF&G 1982f).
It was argued in Section 4.3.1(f)that wolf populations are
unlikely,at their present levels,to be seriously affected
by loss of prey species.The same situation holds for the
Devil Canyon development;only in the very unlikely event
that management objectives require higher wolf populations
would loss of prey species become a potentially significant
impact.Computer modeling of moose populations is being
conducted to assess the impact of altered predat i on rates,
increased acci dents,and habitat loss on moose.These
modeling efforts will also provide insight into possible
changes in predator/prey relationships.
(g)Wolverine
The effects of the Devil Canyon development on wolverine
will be i nsi gni fi cant except for the potenti a1 of increased
trapping as discussed in Section 4.3.3(g).Because wolve-
rines range over large areas,the relatively minor changes
in food availability and the effects of intensive human
act ivi ty nea r the const ruct ion site should not not i ceab1y
affect the few wolverines near the Devil Canyon development
area.
(h)Belukha Whale
As discussed in Section 4.3.1(h),the combined operation of
Watana and Devil Canyon should have no detectable effect on
belukha whales in Cook Inlet.
(i)Beaver
The Devil Canyon project will have a net beneficial effect
on beaver.Several beaver colonies now occurring within
f"""Borrow Site K and near the campsite wi 11 be adversely
affected,but an improvement in downstream habitat resulting
from more stable flows and a lack of ice cover downstream to
Talkeetna will offset these impacts.
No beaver are known to occupy the Devil Canyon reservoir,
and thus,no adverse impact is expected as a result of inun-
dation.However,during the period between the filling of
the Watana and Devi 1 Canyon reservoi rs,some beavers may
colonize this reach and be initially displaced.If the
E-3-469
4-3 -Impacts -Devil Canyon
reservoir level remains stable for several years as a result
of several wet years,beavers will successfully colonize the
impoundment.Beavers will probably attempt to colonize the
impoundment in other years,but the drawdown in August and
September will occur at a critical time when food caches are
being constructed and it is unlikely that beavers will suc-
cessfully overwinter.Approximately 10 beavers are known to
occupy the lakes in and adjacent to Borrow Site K and the
proposed constructi on camp,and these areas wi 11 probably
be lost during construction.
Downstream effects should be the same as with Watana,except
that the 1ack of ice cover from Devil Canyon to Talkeetna
will allow beaver use of some sloughs and side channels that
are subject to freeze-out when ice cover is present.The
mainstem may also be colonized once ice scouring is elimi-
nated.
(j)Muskrat
Construct i on of the Devi 1 Canyon dam shoul d have no di rect
impacts upon muskrats,since no suitable habitat is known
from the constructi on or borrow sites.Some habitat loss
may occur from building camp facilities if ponds and lakes
are filled in for roads,work pads,etc.Downstream effects
will be similar to those described in Section 4.3.1(j).
If construction camp personnel and their families are
allowed to trap in the area,muskrat populations throughout
the lakes lying on either side of the Susitna River could be
affected.Gipson et a1.(1982)found muskrat sign in these
lakes and noted their vulnerability to trapping.
No impact is foreseen from vegetation removal in the im-
poundment zone or from subsequent flooding.
(k)Mink and Otter
Effects of the Devi 1 Canyon project on mi nk and otter wi 11
be similar to those already discussed for the Watana project
(Section 4.3.1[k]),but because of the smaller size of the
impoundment and the more stable water level,effects will be
1ess severe.Because mi nk are most abundant east of Kosi na
Creek,the Devil Canyon project will probably have little
effect on the regional population.Major impacts to otter
and mi nk are loss of habitat,reducti on in prey ava i1 abi-
1i ty,increased human di sturbance,and barri ers to move-
ment.
E-3-470
.....
4-3 -Impacts -Devil Canyon-
Because the combined C Devi1Canyori .project and the Watana
project will resu1 tin permanently Open water from Devil
~Canyon to Talkeetna,mink and otter may be positively
affected.Both species prefer areas of open water in rivers
and streams in wi nter (Barber et a1.1975).Open water
areas in the reservoir during winter should also have bene-
fi ci a1 effects.
(1)Coyote and Red Fox
Coyotes are more common in the Devil Canyon area than in the
Watana area,but they are still sufficiently uncommon that
the project is un1 i ke1y to have any effect on them.As in
the case of the Watana development,foxes will be affected
primarily by increased trappi ng and by destructi on of nui-
sance animals if garbage is not regularly incinerated or if
regulations against feeding are not enforced.Habitat loss
will not be a major impact since foxes tend to occur at mid
and high elevations rather than in the forested areas along
the river.
....
(m)
(n)
Other Terrestrial Furbearers
Lynx,weasels,and marten will all be affected by the Devil
Canyon development primarily by loss of habitat.As in the
case of the Watana development,no estimates of the poten-
t ia1 reduction in numbers of weasel s can be made.Few if
any lynx wi 11 be lost because of the poor habitat and
current low number.Habitat for approximately 14 marten
will be lost to the impoundment and constructi on sites,
borrow sites,etc.If both Watana and Devil Canyon are
built,about 11.5 percent of the middle Susitna Basin marten
population will be lost (access road and transmission line
not included).Both of these estimates are based on the
conservative marten density derived in Section 4.3.1{m).
Marten,lynx,and weasel s may be di sturbed by constructi on
activity,but there is no evidence that they will vacate
areas as a result of these disturbances.
Raptors and Ravens
r-'
I
(i)Construction and Filling
Construction and filling of the Devil Canyon reser-
voi r wou1 d have simi Tar effects on raptors and ravens
to the Watana development,and would increase overall
impact to those species;however,the increase would
4-3 -Impacts -Devil Canyon
represent a relatively small proportion of the total
impact of both developments.
-Habitat Loss
One or possibly 2 of the 15 (12 percent)total
known golden eagle nesting locations in the general
vi ci ni ty of the Devi 1 Canyon impoundment wi 11 be
lost (Tables E.3.150 and E.3.152).The cumulative
loss of gol den eag1 e nests to both projects repre-
sents 44-50 percent of known nest locations in the
project area (Table E.3.150).
No bald eagle nesting locations will be lost as a
result of Devil Canyon construction and fill ing.
No known gyrfalcon nesting locations will be inun-
dated by the Devil Canyon reservoir,but one of the
three total known locations may be located in
Borrow Site K (see Table E.3.150).If this nesting
location is indeed in Borrow Site K,it may be lost
during material excavation,though overall impact
to this species in the middle basin will remain
mi ni ma 1•
One of three (33 percent)known goshawk nesting
locations in the general vicinity of the Devil
Canyon project will be lost to clearing and filling
of the Devil Canyon reservoir (Figure E.3.115,
Tables E.3.150 and E.3.152).The nest location
that will be lost is one of two discovered to date
upstream of the Devil Canyon dams ite.Although the
loss from this goshawk nesting location doubles the
number lost as a result of both reservoi rs,tota 1
impacts to this woodland species are anticipated to
remain minimal because appropriate nesting habitat
appears to be relatively limited in both impound-
ments.
Four of 21 (19 percent)previously used raven nest-
ing locations in the general vicinity of the Devil
Canyon project wi 11 be lost as a result of con-
struction and filling of the Devil Canyon reservoir
(Figure E.3.115,Tables E.3.150 and E.3.152).All
four will be lost by inundation,and one additional
nest (R-19)will remai n only a few meters above
maximum flood level (see Figure E.3.115).
E-3-472
"'"
4-3 -Impacts -Devil Canyon
Although construction and filling of the Devil
Canyon reservoi r wi 11 inc rease the number of used
nesting locations lost to 15 (71 percent of the
previ ous total)(see Tab1eE.3.160),total impact
to ravens is still anticipated to be relatively
low.Loss of nesting locations in Devil Canyon
will probably increase the importance of remaining
cliff areas there (see Table E.3.161)and in side
tributaries.It may also increase the importance
of trees for nesting (see Section 4.3.1[n]).
-Di stu rbance
Five golden eagle nesting locations within or on
the edges of the Devi 1 Canyon impoundment may be
susceptible to disturbance from reservoir clearing
operations (see Figure E.3.116:the two exceptions
are GE-19 and GE-18).One and perhaps two of those
locations will be inundated later (GE-13 and
GE-14).One of the five locations (GE-ll)may be
susceptible to disturbance from the clearing opera-
tions in the Devil Canyon area only if it remains
following the excavation of materials from Watana
Borrow Site E.One other golden eagle nesting
location (GE-18)is about 0.6 miles (0.9 km)down-
stream from the Devil Canyon damsite and may be
susceptible to considerable disturbance as a result
of activities associated with the construction of
the dam itself.
No known bald eagle nesting locations appear sus-
ceptible to disturbance as a result of activities
associated with the construction of the Devil
Canyon dam,clearing operations within the impound-
ment lone,or filling of the reservoir.
Two known gyrfalcon nesting 1ocat ions in the Devil
Canyon impoundment area may be suscept i b1 e to di s-
turbance.One of those locations (GYR-2)may be
suscept i b1 e to some di sturbance duri ng the reser-
voir clearing and the subsequent increase in human
presence as recreation activities develop and
increase along the impoundment edges.A second
location (GYR-3)may be susceptible to considerable
disturbance from excavation and transport of
materi a1 s from Devil Canyon Borrow Site K.
At least two known goshawk nesting locations (tree
nests)may be susceptible to disturbance from
E;"3-473
4-3 -Impacts -Devi 1 Canyon
construction and filling of the Devil Canyon reser-
voir.One of these nesting locations (GOS-2)is
wi thi n the Devi 1 Canyon reservoi r.It may be sus-
ceptible to disturbance from material excavation
(0.13 miles [0.2 km]to the west)at Watana Borrow
Site I (see Section 4.3.1[n],[ii])and will even-
tually be felled during reservoir clearing opera-
tions prior to inundation (Figure E.3.116).The
other nesting location (GOS-3)is situated well
above the reservoi r 1evel,but di sturbance from
human presence may increase as recreational activi-
ties develop along the impoundment edges.
Six raven nesting locations within or on the edges
of the Devil Canyon impoundment may be suscepti bl e
to disturbance from reservoir clearing operations,
but four of these will eventually be inundated (see
Figure E.3.116:the exceptions are R-19 and R-21).
One of the locations not inundated (R-19)will
remain only a few meters above maximum flood level.
The other nesting locations that is not inundated
(R-21)is about 0.47 mile (0.7 km)downstream from
the Devil Canyon damsite and may be susceptible to
disturbance during construction of the dam.
(0)Waterbirds
Initially the clearing and construction activities at Devil
Canyon may cause a temporary loss of suitabl e habitat for
waterbi rds.The Devi 1 Canyon impoundment wi 11 have a rel a-
tively stable water level with a drawdown of only 1 m for
most of the year (less than 1 m in wet years).This should
allow for the development of some vegetation in the impound-
ment,although suitable shallow shoreline areas will be
somewhat limited.The open-water area near each end of the
reservoir should benefit some early and later migrants when
other waterbodies are frozen,and the relatively stable
water level in each year will allow a low level of use,
typical of large lakes of the region,for nesting by water-
birds along the shoreline.On the other hand,species of
alluvial and fluviatile shoreline habitats currently using
the impoundment area wi 11 be el imi nated.Breedi ng habitat
for harlequin duck,common merganser,semipalmated plover,
spotted sandpiper,wandering tattler,arctic tern,and
di pper wi 11 be inundated.No si gni fi cant amount of shore-
bi rd feedi ng habitat wi 11 be created by the Devi 1 Canyon
impoundment because of the small drawdown and steep shore-
1 i nee
E-3-474
-
4-3 -Impacts -Devil Canyon
Downstream effects will be simil ar to those di scussed in
Section 4.3.1(0}.These will consist mostly of distribu-
tional shifts and minor changes in relative abundance of
riparian species as vegetation proceeds through the succes-
sional sequence described in Section 3.2.1.
.-
-
(p)Other Bi rds
The Devi 1 Canyon development wi 11 resu1 tin the same types
of impacts (habitat loss,habitat alteration,disturbance,
direct mortality)with the same effects on terrestrial and
shoreline birds as the Watana development (see Section
4.3.l[pJ)•
F1 oodi ng of the Devi 1 Canyon impoundment wi 11 increase the
proportionate loss of forest habitats in the middle basin by
several percent over that lost to the Watana development
(Table E.3.165).The largest losses will occur in closed
birch forests,conifer-deciduous forests and open spruce
forests (Table E.3.166).The total loss to the population
within 10 miles (16 km)of the Susitna River between the
McLaren River and Gold Creek resulting from both Watana and
Devil Canyon Reservoirs and facilities is between 10 and 15
percent for the following species:spruce grouse,hairy
woodpecker,northern three-toed woodpecker ,boreal chi cka-
dee,brown creeper,varied thrush,hermit thrush,Swainson's
thrush,ye110w-rumped warbler,blackpol1 warbler and northern
waterthrush.For a few species,the proportionate loss to
Devil Canyon results in a substantial additional loss over
the Watana Development alone.Kessel (unpublished data)
cal cu1 ated order-of-magnitude losses for number of sma 11-
and medi um-si zed bi rds that wou1 d be lost to the Devi 1
Canyon facilities (Table E.3.166).An estimated 17,300
breed i ng bi rds will be lost to the Devi 1 Canyon fac i1 ity,
approximately 1 percent of the population within 16 km of
the Susitna River between the McLaren River and Gold Creek.
As is the case for the Watana development,the dipper will
be affected by loss of breeding habitat in the lower reaches
of feeder streams and loss of winter habitat (open water)in
both feeder streams and the Susitna River itself.However,
open-water below the dam should compensate for this loss of
winter habitat.
-
(q)Non-game (Small)Mammals
The types of impacts on sma 11 mammals that wi 11 result from
construction of Devil Canyon dam will be similar to those
already discussed for the Watana dam (see Section 4.3).The
E-3-475
4-3 -Impacts -Access
major impact will be loss of habitat due to clearing opera-
tions and subsequent flooding.The total area affected
(approximately 34.km 2 ,8401 acres)and percent of forested
land affected (0.7 percent)are much smaller than in the
Watana reservoir area.The impacts on small mammals are
thus expected to be proportionately smaller.
4.3.3 -Access Roads and Railway
(a)Moose
Anticipated impacts on moose of the gravel access road from
the Denali Hi ghway to the Watana dams ite and the 1ater
constructi on and operati on of the Devil Canyon access road
include a loss of habitat,alteration of habitat,distur-
bance and subsequent avoidance of the highway,interference
with seasonal movements,and mortality.Moose will also be
greatly affected by the indi rect impacts of the access road,
particularly hunting.Moose numbers will decline as a
result of hunting mortality and avoidance of the corridor by
moose.The railway from the Gold Creek area will have simi-
lar effects to those mentioned for the access roads,except
that hunting mortality should be lower (as a result of poor
vehicular access)and collision mortality during the winter
may be hi gher.
(i)Mortal ity
The prima ry impact of the access roads wi 11 be the
provision of improved public access to previously
remote areas in the Susitna Basin.In turn,improved
access will probably result in localized declines in
moose as a result of hunt i ng and avoi dance of the
highway corridor because of disturbance.Declines in
moose along newly opened roads or along roads in
areas opened for hunting have been reported for a
number of northern areas (Goddard 1970,Cumming 1974,
Ritchey 1974,Beak 1979).Although a good portion of
these decl i nes in moose was the result of hunting
mortality,moose probably also avoid areas in the
vicinity of access corridors during the hunting
period.
A decline in moose numbers during construction of the
Watana access road can be expected as a resul t of
hunting.Effects would probably be most severe in
the vicinity of campsites or the townsite.Public
access to the Susitna Basin will increase once the
road is operational,and furth~r increases in hunting
E-3-476
~,
4-3 -Impacts -Access
pressure will occur with resultant increases in hunt-
ing mortality of moose.Because the moose population
will already be stressed by impacts associated with
the Watana development and the subsequent redistribu-
tion of moose within the Susitna Basin,disturbances
associated with hunting and hunting mortality may
further aggravate impacts to the moose popul at i on.
Because the Watana development will reduce the carry-
ing capacity of the Susitna Basin for moose,it is
possi b1e that moose numbers will temporarily exceed
those optimal for sustai ned producti vity.Assumi ng
that surplus moose may be present,carefully managed
hunting may effectively mitigate for the indirect
project effect of overutilization of remaining forage
(see.Section 4.4).
Construction and operation of the Watana-Devil Canyon
access road segment and the railway will result in
simi 1ar but 1ess severe impacts on moose.The Devi 1
Canyon segment will provide new access to a rel ative-
1y smaller area,much ofwhi ch is poorer quality
moose habitat than is the Watana dam area.The rail-
way wi 11 not provide as easy an access route to the
genera 1 pub 1ic as the roadways,and its use can be
better controlled.Hunting pressure consequently
will not increase as in the case of the access roads.
In addition,much of the area that wi 11 be affected
by railway access supports relatively low numbers of
moose as compared to lower reaches of the Susi tna
River.
During the construction and operation of the access
roads and railway,moose may be k'i11ed as a result of
collisions with vehicles.High volumes of road
traffic are expected along the Watana and Devil
Canyon access roads during construction of the dams
(primarily from workers commuting to the site),and
the number of moose killed will be substantial,par-
ticularly during winters of deep snowfall or when
darkness or poor weather results in poor vi si bi 1i ty.
Collision mortalities along the railway could also be
substantial.~n additional 8 train trips per week in
each di recti on are.expected duri ng the constructi on
of the Devil Canyon dam.Rausch (1958)reported
adjusted kill totals of 366 and 179 moose along a
86.9 km section of the Alaska Railway (Houston to
Talkeetna)during the winters 1955-56 and 1956-57,
respectively.During the winters of 1970-1971
E-3-477
through 1978-79,annual moose kills along the Wi11ow-
Ta lkeetna porti on of the A1 aska rail way ranged from 0
to 151 animals (ADF&G unpublished data).Because
moose are easily trapped within the steep snow
embankments along railway lines and are usua1}y more
abundant in vall ey bottom habitats duri ng wi nters
with high snows~higher numbers of collision mortali-
ties occur along rights-of-way in low elevation areas
during severe winters.
ii)Loss of Habitat
Construct i on of the Watana and Devil Canyon access
roads and the railway will result in loss of habitat
associated with the construction corridor and borrow
pits.Although the actual removal of moose browse
will be small in relation to its availability in
other areas of the Susitna Basin,the effective loss
may be greater if moose avoid the access corridors or
if migration routes are blocked.As discussed above,
moose will to1 erate di sturbance along access corri-
dors if they are not hunted.However,if hunting is
permitted,moose may avoid an area of several kilo-
meters from the corridor,consequently increasing the
effective area of lost habitat.
Based on existing information,no special use areas
for moose such as wintering range,calving areas,or
breeding concentrations will be rendered unusable by
the road access corridors.However,because most
special use areas will be inundated by the impound-
ments,these road corridors could affect the location
of new special-use areas.Anticipating such changes
is obviously difficult.
The problem of rail way corri dors in moose wi nteri ng
areas and resulting collision mortalities has already
been discussed.
(iii)Alteration of Habitat
Construction of the access road and railway will
necessitate the use of gravel berms that may impede
or alter drainage systems (Boelter and Close 1974,
Kemper et ale 1977).Permanent flooding of forested
a reas may result in the loss of some moose habitat
through killing of trees and shrubs.However,growth
of aquatic plants within flooded areas may partially
compensate for this loss by providing additional
E-3-478
-
-
-
(b)
summer forage.Drai nage of wetl and areas may result
in a temporary increase in the growth of seral shrub
communities,but without periodic flooding or
disturbance,these areas will eventually develop into
forest stands with low browse production.
(iv)Interference with Seasonal Movements
The proposed road access corridors will cross several
a reas where moose mi grate seasonally between summer
and wi nter ranges (ADF&G 1982a).Concentrati ons of
movements by radio-collared moose that may be affect-
ed by the Watana road i ncl ude the Watana-Butte Creeks
area,and the Watana-Deadman creeks area (Section
4.2.1[a]).
During construction,mechanical activities may pre-
vent some moose from crossing the road corri dors,
primarily as a result of moose avoiding the construc-
tion area.Avoidance of the road corridor would pro-
bably be most severe duri ng the hunti ng season,if
hunting is permitted.Steeply sloped road berms and/
or the creation of deep snow embankments from road-
plowing may act as physical barriers to moose cross-
ings.As discussed earlier,the railway may inter-
fere with movements of moose during the winter and
early spring periods when snow embankments may either
block movements by moose or trap animal s withi n the
cleared right-of-way.
Cari bou
The access road between the Denali Highway and the two dam-
sites is 1ikely to have a substantial effect on caribou
movements.Few cari bou movements have been recorded in the
area traversed by the Devil Canyon to Watana dam segment,
and the western segment between the two dams and Gold Creek
should not pose a serious problem to caribou.The segment
between the Denali Highway and Watana dam,however,traver-
ses an historically important area of the herd's range,
which is currently used by a resident subherd of up to 2500
caribou and also by some caribou from the main herd.The
road is most likely to affect the herd by increasing mortal-
ity from collisions with vehicles and from hunting,and by
altering movements between the area west of the road and the
remainder of the herd1s range.There may also be a slight
increase in wolf predation in the area,since wolves often
E-3-479
4.3 -Impacts -Access
use roads to their advantage while hunting caribou (Roby
1978)•
Detailed information on the effects of roads and associated
human activities (e.g.,vehicle traffic,construction acti-
vity,presence of workers)on caribou comes primarily from
four sources:(1)studies by the ADF&G along the TAPS
corridor since 1974,and along the Kuparuk oilfield access
road since 1978;(2)a two-year study by Fancy (in press)in
a floodplain area used by large numbers of caribou moving to
and from insect-relief areas;(3)data from a study by Roby
(1978),who worked with ADF&G along the TAPS corridor;and
(4)a two-year study conducted along the Kuparuk oilfield
access road by Curatolo et ale (1982).Alyeska Pipeline
Service Company is also funding a three-year study along the
TAPS corridor as a IIsecond opinion"to the ADF&G studies;
however,no reports have been released after two years of
study.All of these studies involve the Central Arctic Herd
on Al aska I s North Slope.
The results of these studies are somewhat contradictory,and
as a result,caribou biologists disagree on the severity of
road effects on caribou.ADF&G studies (Cameron and Whitten
1979,1980;Cameron et al.1979)have concluded that caribou
cows and calves avoid the Prudhoe Bay oilfield,based on a
lower percentage of cal ves in caribou groups observed from
the roads in thei r study area as compared to aeri al si ght-
ings over a larger area.But,along the Kuparuk oilfield
access road (oriented E-W and thus not confused by latitudi-
nal biases),calf percentages have not been found to differ
from those expected in three years of study (Cameron et al.
1981).During an aerial calving survey along that road in
1980,no calves were seen within 2.7 miles (4 km)either
side of the road,but this was not the case in 1978 and
1979.Few calves have been born within the Prudhoe Bay
complex in recent years.The Central Arctic Herd has been
steadily increasing in si ze each year,and productivity has
been "excellent"(Cameron et ale 1981)in spite of the
localized effects on caribou distribution and group composi-
tion.
Recent detailed studies involving continuous observations of
caribou as they approach roads and pipelines have found that
most caribou will cross roads with light-to-moderate vehicle
traffic,but that caribou will often first try to find a way
around the obstacle (paralleling movements),and some groups
(10-14 percent for the most detailed study)may refuse to
E-3-480
1""*
-
....
-
-
4.3 -Impacts -Access
cross at all (Fancy,in press).Preliminary results by
Curatolo et ale (1982)have found that the proportion of
groups that crossed the Kuparuk oilfield road and pipeline
was significantly less than that expected (control).Many
groups left their study area paralleling the road and pipe-
1i ne,and thus the proportion of groups that eventua 11 y
crossed could not be determined.
The responses of individual caribou to roads and traffic are
extremel y variable;some animal s appear to avoid 1 i ghtl y
traveled·roads entirely,whereas others will cross roads
during rates of traffic exceeding one vehicle per minute
with no observable response.In general,however,moving
vehicles and/or the presence of workers will alter the local
movements and behavior of cari bou.Horej si (1981)reported
that 88 percent of the caribou he observed along the
Dempster Highway reacted to amoving pickup truck by running
or trotting away.A fleeing animal can expend eight to
twenty times the cost of basal metabolism,at the expense of
body growth,development,and reproduction (Geist 1975).
The greatest concern for disturbance effects on caribou is
for cows in late pregnancy and cows with young calves.
Female caribou are particularly sensitive to disturbances
during the calving period (Lent 1966,Bergerud 1974b,Calef
et al.1976,Surrendi and DeBock 1976),and disturbances at
this time are more likely to result in lowered recruitment
because of premature travel by calves,disruption of cowl
calf bonds,or trampling (Lent 1966,Geist 1971b,Bergerud
1974b,Surrendi and DeBock 1976).Some calving has been
documented north of the Sus itna Ri ver,but the road has been
realigned so that it is to the west of the areas where most
calving has recently occurred.Cows calving in the area may
avoid the road during the period of heavy use,but this will
affect only a small number of animals.
Large vol urnes of vehi cl e traffi c are expected duri ng peak
construction years,including 20 project support materials
vehi cl es per day,hundreds of tri ps per day by workers
driving to the site,and 70 project heavy trucks per day
(Table [.3.162).If the road is opened to the public during
or after construction,high traffic rates will continue.
The traffic volume during the caribou studies cited earlier
was only a small fraction of that expected during dam
constructi on.A few cari bou wi 11 cross the road regardl ess
of high traffic frequencies,but the majority will probably
cross only if lulls in traffic are provided.Since the area
west of the road is currently a peripheral part of the main
herd's range,failure of most animals to cross the road will
E-3-481
4.3 -Impacts -Access
not cause a maj or impact.As the herd increases in si ze,
however,the importance of the area to the herd will greatly
increase.It is thus important to design and operate the
road so as to permit free crossings by caribou during the
operation phase of the project.
The physical presence of a raised gravel road,in the
absence of vehicles and human activities,will not be an
insurmountable barrier to caribou movements (Surrendi and
DeBock 1976).The exception to this is that plowed or
blown snow along the road could,in combination with the
raised road surface,act as a physical barrier to caribou
movements (Surrendi and DeBock 1976).Caribou tend to
seleCt the lowest berms when crossing roads (Cameron and
Whitten 1976,Surrendi and DeBock 1976,Roby 1978),and
various studies have shown that caribou are wary of berms
they cannot see over (Hanson 1981).
The Nelchina herd has been important to both sport and sub-
sistence hunters because of its size and proximity to popu-
lation centers.In 1981,6662 people applied for 1600 per-
mits to hunt for Nelchina caribou.The permit system cur-
rently in use will have to be continued if only the annual
increment is to be harvested as stated in the herd manage-
ment pl an (ADF&G 1976).Publ ic access provided by the
Denal i access road wi 11 have a greater effect on the di s-
tribution of hunting pressure than it will on the actual
number of caribou harvested,since hunter success is cur-
rently very high.The Susitna-Nenana subherd is resident in
the access road area and,al though the rate of exchange of
individuals with the main herd is unknown,the presence of
the Watana impoundment in conjunction with heavy hunting
pressure will probably result in a substantial decrease in
thi s sub herd.
(c)Dall Sheep
The effect of vehi cl e traffi c along the access road shoul d
be insignificant,since sheep are not expected to occur
close to the roads.MacArthur et al.(1982)found that
only 19 of 215 documented passes (8.8 percent)of sheep by
vehicles evoked heart rate responses,usually of low ampli-
tude.Moreover,73.7 percent of all heart-rate responses
occurred when vehi cl es passed withi n 82 feet (25 m)of the
sheep.They reported that only 2 of the 215 vehicle passes
(0.9 percent)they recorded evoked withdrawal responses by
sheep.In Denali National Park,Tracy (1977)found that the
strength of reaction s and the pe rcentage of sheep showi ng
visible reactions to buses and visitors decreased with
E-3-482
-
4.3 -Impacts -Access
i ncreas i ng di stances between the sheep and the road.She
recorded no reactions by sheep at distances exceeding
2460 feet (750 m)from the road,whereas strong reactions
were recorded only at distances less than 1312 feet (400 m).
Dall sheep have continued to use lambing and wintering areas
along the Dalton Highway (Hemming and Morehouse 1976,Fancy
1980),in spite of intensive pipeline construction and
vehicle traffic along that road.Disturbance due to ai r
traffice is treated in Section 4.3.1{d).Increased
disturbances from human access as described in Section
4.3.1 (d)for the constructi on phase wi 11 al so occur duri ng
operation as recreational use of the area increases.
If the project area is opened to the public following con-
struction,there will 1 ikely be an increase in hunting
pressure in locations adjacent to the access roads and the
reservoir.The number of sheep harvested in the area is not
expected to increase greatly,however,because all or most
legal rams in the area are al ready being harvested each
year.Serious population depletions resulting from the
increased hunting pressure are thus not expected to occur.
-
.-
(d)Brown Bear
Both the Denali-Watana and Watana-Devil Canyon access road
segments traverse prime brown bear habitat.Potential
impacts of the access roads on brown bears include inter-
ference with movements,increased hunting mortality,and a
decrease in acceptable denning and feeding areas.Direct
mortality from hunting and nuisance animal control will pro-
bably have the greatest effect on the population in the long
term.
Tracy (1977)reported on the.reactions of brown bears to the
Denali Park Road.She found that the densities of bears in
study plots away from the road were consistently greater
than densities along the road,suggesting an avoidance of
roads by bears even where no hunting occurs.Many bears
have habituated to the road,however,and those seen near
the road were frequently engaged in such activities as nurs-
ing,playing,and sleeping,which suggests security and
relaxation.The literature also includes a paper by Elgmark
(1976),who reported that construction of a network of logg-
ing roads in Norway resulted in a lower density of brown
bears,and a report by Miller and Ballard (1982)on the
apparent short-term defl ection of brown bear movements by
the Glenn Highway in Alaska.
E-3-483
4.3 -Impacts -Access
The access road is likely to cause some alterations in the
movements of brown bears,but there is 1 ittl e ev idence to
suggest that it will block bear movements altogether.
Revegetati on of the road shoul der will create forage whi ch
is attractive to brown bears,especially during early
spring,when such areas will green-up earlier than
surrounding vegetation.However,because brown bears in the
middle basin are hunted,they are not likely to feed on
berries and other foods occurring adjacent to the road
during hunting season,and thus there will be a decrease in
the avai 1abil ity of foods as a result of the road in that
season.Several dens have been found in the Denal i Highway
to Watana access road segment.Brown bears in the proj ect
area do not appear to re-use existing dens and the
availability of denning habitat does not appear to limit the
population.However,it is likely that brown bears will
find unacceptable the denning area used by three different
bears in 1980 and 1981 near the proposed road once the road
is present.
Abandonment of dens by bears in winter can result from human
activity near the den (Craighead and Craighead 1972a,b;
Harding 1976)or from disturbance caused by helicopters
(Reynol ds et al.1976).Frozen ground woul d then prevent
the bears from digging new dens.Disturbance of bears in
winter dens during road construction may cause the death of
several bears.
Although some brown bears are now harvested from the remote
areas of the middle basin,most hunting occurs along or near
the Denali Highway.The improved access resulting from the
road and reservoir will probably cause a large increase in
the number of brown bears killed by hunters in the basin.
Habitutated bears,particularly young bears,will become
particularly sl.lsceptible to hunting.Additional mortality
will occur from the destruction of habituated and nuisance
bears.
(e)Black Bear
The access road wi 11 impact bl ack bears primari 1y through
improved access for hunters.81 ack bears do not usually
occur near the proposed road north of the Deadman Lake area,
and much of the Watana-Devil Canyon segment is at elevations
above acceptable black bear habitat.Road construction
could cause abandonment of dens,particularly in the lower
Deadman Creek area and near the Devil Canyon damsite.The
probability of bear mortalities caused by collisions with
vehicles is very low.
E-3-484
4.3 -Impacts -Access
-
-
(f)
(g)
Wolf
The maj or effect of the access route on wol ves wi 11 be an
increase in the numbers of hunters,trappers,and con-
struction workers able to shoot wolves in the area.
However,wolves may also be affected by disturbance from
construction activities and traffic,and small numbers may
be killed by vehicles.The number killed by vehicles is
likely to be greater if wolves become habituated to vehicles
through being fed.Since wolves do habituate readily to
traffic and noise under most circumstances,disturbance is
unlikely to have major effects.However,wolves appear to
be more sensitive to disturbance during the denning season.
Carbyn (1974)documented abandonment of two wol f dens near
highways after the roads were upgraded and traffic vol urnes
increased.The proposed Susitna aCCess route passes through
the home ranges of at least three wolf packs.Two den sites
and one rendezvous site are known from the general vicinity
of the access route;additional sites most likely exist.
Impacts from increased access by hunters and trappers cannot
be quantified but may be severe.As many as 8-10 wolves per
year have been taken in the immedi ate vi ci ni ty of the pro-
posed impoundments since 1976-77 (ADF&G 1982f)in spite of
the relative inaccessibility of the area at present.In-
creases in the number taken may be beyond the capabil ity of
the population to replace,or may reduce the ability of this
population to produce excess animals that presently disperse
to areas even more heavily hunted.
Wolverine
The di rect loss of habitat caused by the access road wi 11
have an ins i gnifi cant effect on wolveri ne.Hornocker and
Hash1s (1981)statement that "the size and shape of
(wol veri ne home)ranges were not affected by ri vers,reser-
voi rs,highways or mountai n ranges lt suggests that the road
and associated traffic will also have an insignificant
effect on wolverine movements and availability of prey.It
is not clear whether wolverine will utilize carcasses of
animals killed by collisions with vehicles,but this is a
possibil ity,especially during periods of infrequent vehicle
use.The potential for wolverines to be killed by vehicles
is very low,considering the low densities of wolverine and
their wariness.
Increases in trapping pressure as a result of improved
access is more 1i kel y to affect wol veri nes than any other
E-3-485
4.3 -Impacts -Access
project-related activity.Wolverines are highly susceptible
to trapping because they travel widely and are readily
attracted to baits.Hornocker and Hash (1981)reported that
all of the wolverines they captured were missing one or more
toes,and many had broken teeth;many of these mut i1at ions
were attributed to encounters with leg-hold traps.Van Zyll
de Jong (1975)stated that II pre dation by humans appears to
be the most 1ike1y factor to have affected the number of
wol veri nes.Di rect evi dence of negative effects of human
exploitation on wolverine populations is not available,but
i ndi rect evidence from decl i ni ng producti on of wolveri ne
pelts and the disappearance of the species from areas with
relatively dense human populations strongly suggests that
exploitation by man contributed to the decline.1I Fifteen of
the 18 known wolverine mortalities in Hornocker and Hash's
(1981)study were human caused.Increased trapping pressure
in the Susitna Basin will probably cause some instability in
the social structure of the population,thus causing notice-
able shifts in home ranges.However,population effects of
trappi ng mortal ity woul d be diffi cult to detect because of
emigration of wolverine from the large parcels of wolverine
habitat surrounding the basin into the affected areas.
Wilderness or remote country where human activity is limited
appears essential to the maintenance of viable wolverine
populations (Van Zyll de Jong 1975,Hornocker and Hash
1981).However,Hornocker and Hash (1981)reported that
they found uno di fferences in wol veri ne density between the
wilderness and nonwilderness portions of our study area,nor
was wolverine movement,habitat use,and behavior different.
Marked wolverines used both areas and several individuals'
home areas overl apped both wil derness and nonwil derness.
The nonwilderness portion,about one half of the study area,
is used by humans primarily for logging and recreation;
1oggi ng roads and foot trai 1s prov ide access to ri ver and
stream bottoms and lower elevations during summer and fall
months.Loggers,summer recreationists,and hunters make
considerable use of those areas.1I They went on to say,
however,that wolverines and humans were effectively sepa-
rated because the wolverines were at higher elevations away
from peopl e duri ng summer and fall,and 1 ittl e use of the
area by humans occurs during winter when wolverines move to
the lower elevations.A similar situation will exist in the
middle Susitna Basin;the most intensive human use of the
area will occur in summer when wolverines are using
primarily tundra habitats.Access to these tundra areas
afforded by the roads and transmission corridors may cause
several wolverines to avoid portions of their range.Winter
E-3-486
-
-
-
-
4.3 -Impacts -Access
use of the impoundment areas,except for trapping,should be
considerably less than that during snow-free periods.
(h)Furbearers
The construction of the access road and the railway will
result in some habitat loss for terrestri al furbearers,and
may result in'habitat loss for aquatic furbearers if wet-
lands are degraded.Minor effects on the local distribution
of individual s of some species may al so occur along the
road.For example,Hawley and Newby (1957)believed that
habitat openings were a psychological barrier to marten.
Although subsequent studies have found that marten regularly
cross openi ngs 328-656 feet (100 to 200 m)wide (Koehl er et
ale 1975,Soutiere 1978),the access route will result in a
redistribution of home ranges ,and many marten will be
forced to realign their home ranges along the road.
Similarly,some foxes may avoid the road area,but most will
probably habituate to traffic.Tracy (1977)found several
fox dens within 328 feet (100 m)of the road in Denali
National Park and observed foxes travel ing along the road
while vehicles were using it.However,such habituation to
human presence probably occurs only in the absence of
trapping pressure.Access routing (Figures E.3.79 to
E.3.82)is very near several red fox denni ng compl exes,
which,in the absence of mitigation could be made unusable
or be physically destroyed.
Access to the Watana si te from the Denali Hi ghway has the
potential to negatively impact large numbers of beaver.
Approximately 65 beaver occupy 12.3 miles (18.4 km)of upper
Deadman Creek,a relatively broad stretch along which the
access route is.proposed.Similar beaver densities may
occur in adjacent areas designated as material sites.Use
of the valley bottom for the road and material sites will
negatively impact at least 40 beaver.
Two opposing scenarios.are reported in the literature on
possible effects of road construction on beaver habitat.In
one (Watson et al.1973~,diversion or impoundment of stream
and subsurface water flows by roa.d berms has a negative
effect on downstream beaver ponds and lakes through the
introduction of heavy sediment loads and increased
turbidity.These are the effects of bank instability caused
by the clearing of riparian vegetation associated with
ri ghts-of..;,way constr.uct i on and mai ntenance.Heavy sediment
loads result in the gradual fill ing of downstream ponds and
E-3-487
4.3 -Impacts -Access
lakes;increased turbidity reduces light penetration and
inhibits growth of aquatic vegetation.
Alternatively,ponding at culverts and bridges and restric-
ted subsurface flows caused by road berms have often created
attractive sites for beaver colonization.The use of brid-
ges and culverts.as damsites by beaver is well documented
(Bradt 1947,Hodgdon and Hunt 1953,Huey 1956,Rutherford
1964,Johnson and Gunson 1976).However,habitat improve-
ment through the introduction of a road in prime beaver
habitat along upper Deadman Creek is unlikely,and a reduct-
ion in beaver numbers is expected there.
Muskrats along the proposed access routes wi 11 be affected
through habitat loss and increased trapping mortality.
Gipson et ale (1982)found sign of over wintering muskrats
in several of the lakes lying along the proposed route from
Watana dam to Devil Canyon dam.Many of these muskrats
occurred in conjunction with the high beaver densities noted
along the proposed route from the Denal i Highway to Watana
dam.
In addition to being very sensitive to water level changes
which could occur because of draining or filling of ponds
and lakes (Bell rose and Brown 1941),the small foraging area
of muskrats,(usually within 32.8 ft [10 m])of their house)
makes them sensitive to loss of their preferred foods of
aquatic and emergent plants (Butler 1940).
No substantial effects are anticipated on mink or otter
populations with the possible exception of increased rec-
reational disturbance resulting from public access to
streams that may be important to these species.
The major impact of the access routes on furbearers is rela-
ted to the probable increase in trapping pressure.The
Susitna Basin is not heavily trapped at present and,for
some species,the area may be a source from which animals
disperse into more heavily trapped adjacent areas.The spe-
cies that will be most affected by increased trapping pres-
sure are probably marten,beaver,muskrat,and red fox.
Marten are the most economically important furbearer in the
basin;beaver and fox are also heavily exploited in adjacent
areas.Mink and otter may be affected to a 1esser extent J
since they do not appear to be particularly desirable
species in this part of Alaska (Gipson et ale 1982).
E-3-488
,~--,
-
4.3 -Impacts -Access
(i)Raptors and Ravens
(i)Denali Highway to Watana Damsite
Some nesting habitat for ground-nesting raptors
(e.g.,merl ins,northern harri ers,short-eared owl s)
may occur along the Denali-Watana section of the
access road and may be lost;however,cl iff-nest i ng
habitat does not appear to occur within at least a
few kilometers of the route,and only one tree-nest
appears to be associated with it (Roseneau 1982
Pe rsona 1 Commun i cat i on)•
No golden eagles,gyrfalcon,goshawk,or raven nest-
ing locations will be lost as a result of road con-
struct i on between the Denali Hi g hway and the Watana
campsite and Watana damsite.
One bald eagle nesting location (BE-6,see Tables
E.3.160 and E.3.162)in Deadman Creek will be physi-
cally destroyed by access road construction between
the Denali Highway and the Watana damsite.The
active nest is located in a balsam poplar tree in a
small stand of poplar and white spruce.The current
road al i gnment passes di rectl y through the stand of
trees.Thi s stand appears to be the best (and pos-
sibly only)potential bald eagle nesting habitat
along Deadman Creek.
-
.....
(i i )Watana Damsite to Devil Canyon Damsite
-Habitat Loss
Some nesting habitat for ground-nesting raptors
(e.g.,merl ins,northern harriers,short-eared
owls)and tree-nesting raptors (e.g.,merlins,
goshawks,sharp-shi nned hawks and owl s)may occur
along the Watana-Devil Canyon section of the access
road and may be lost;however,no known cliff-
nesting habitat will be lost.
-Disturbance
Two nesting locations,one golden eagle (GE-18)and
one raven (R-21),may be susceptible to disturbance
from the Watana-Dev il Canyon secti on of the access
road.Both are near the western end of the road,
within about 0.2-0.3 miles (0.4 km)of the center-
line (see Table E.3.160).Furthermore,a bridge
will be built across the river about 0.5 miles
(0.8 km)downstream from the golden eagle location;
E-3-489
4.3 -Impacts -Access
the activity during construction may result in
temporary abanonment of this site (see Section
4.4.3[a])•
(iii)Devil Canyon Damsite to Gold Creek
-Habitat Loss
Some nesting habitat for ground and tree-nesting
raptors may occur along the proposed railroad
access route from Devil Canyon to Gold Creek;how-
ever,no known nesting locations will be lost.No
known cliff-nesting locations occur in this section
of the access road.
-Disturbance
The proposed railroad link between Devil Canyon and
Gold Creek will pass about 0.3 mile (0.5 km)
southeast across the river from one bald eagle
location (BE-8,see Table E.3.160).Considerable
disturbance may result from construction activities
(Table E3.160)(see Section 4.4.3[aJ).
(j)Waterbirds and Other Birds
Impacts of access roads on birds will result from habitat
loss and alteration.di sturbance from traffi c and peopl e
associated with the project,direct mortality from both
collisions with vehicles and increased hunting pressure,and
i ndi rect effects on nest i ng success because of increased
recreational use.The most significant of these impacts
vary with species group (Table E.3.166),but for most
species,none will be as serious as the impacts resulting
from the flooding of the impoundments.
A crude estimate of 2000 breeding birds will be lost
because of habitat loss from construction of the access road
(Table E.3.166).Largest numerical losses will occur in the
following species:tree sparrow (550),savannah sparrow
(416).Wilson's warbler (356),and white-crowned sparrow
(156).
Habitat alteration wi 11 i ncl ude some openi ng of the canopy
where the road passes through closed forest and shrubl and.
This may result in a change in species composition of breed-
ing birds.In at least one instance (Jeglum 1975),building
of a road that blocked drainage through a portion of the
-
-
....
.....
....
i
4.3 -Impacts -Access
boreal forest has been shown to improve habitat for some
waterb i rds.
Effects of disturbances from road traffic will probably be
minor for most species,but there are few quantitative data
to support thi s argument.In one of the few quant itat ive
studies of disturbance to songbirds,Ferris (1979)reported
no differences in breeding bird densities adjacent and
distant from 4-lane and 2-lane highways in Maine.He did
find a small difference in species composition that was
ascribed to edge effects adjacent to the highway.
Some species of low open habitats may be more affected.Van
der Zande et ale (1980)found that two and possibly three of
the four shorebi rd species they studied nested at lower
densities up to at least 0.67 mile (1 km)from both busy and
relatively quiet roads.In some cases,nesting density was
reduced by 60 percent.Quantitative studies of species
nesting in open habitats in Alaska are not available,but
simil ar effects coul d occur wi th ptarmi gan,some shorebi rd
species,and some passerine species.
Some birds will undoubtedly be killed by road traffic.
Species such as spruce grouse will be attracted to the road
as a source of gravel (Carbyn 1968),whereas scavengers,
including ravens and possibly eagles,will be attracted by
road-killed wildlife.However,mortality from collisions
will probably have a lesser effect on gamebirds than will
increased hunting pressure.The middle Susitna Basin is
relatively inaccessible at present,and it is likely that
little game bird hunting occurs there.When road access is
provided,hunting will undoubtedly increase and will prob-
ably be concentrated along the road.Weeden (1972)found
that hunters killed a much larger proportion of ptarmigan
within 2624 feet (800 m)of the Steese Highway than farther
away.The same would likely be true for other game birds.
Increased recreational use or human disturbance in wilder-
ness areas in other parts of North America has been associa-
ted with various behavioral effects,and in some cases with
reduced nesting success.Loons and grebes appear to be
particularly affected by boating activity.Nesting success
in both groups has been shown to decrease with increasing
presence of boats and canoes (Ream 1976,Euler 1978,
McIntyre 1978).Power boats may al so destroy loon nests
through wave action (Vermeer 1973).
Recreational activities,particularly in open habitats,may
result in nest destruction by predators after incubating
E-3-491
4.3 -Impacts -Transmission Lines
adults,are flushed.This has been documented for at least
two duck species and the Canada goose (Hammond and Forward
1956,MacInnes and Misra 1972).Presumably,similar nest
losses coul d occur in upl and tundra species fl ushed from
their nests by all-terrain vehicles or other recreational
activities.
(k)Non-Game (Small)Mammals
The proposed access roads to the Susitna dams will traverse
a wide variety of small mammal habitats,but will mostly be
in shrubland and tundra (Table E.3.84).Although all
species of small mammals are expected to be affected to some
extent,only the species most affected (those living in
shrubland and tundra habitats)will be discussed below.
Impacts include increased mortality,impeded dispersal,
presence of new habitats,and changes in drainage patterns.
In areas of moist tundra,the gravel berm that will consti-
tute the roadbed will act as a barrier to dispersal of small
mammals.Traffic on the road will cause increased mortality
in local populations.However,no serious changes in re-
gional population sizes or structures are expected.
The well-drained gravel of the roadbed will provide ideal
burrow sites for arctic ground squirrels and singing voles.
The revegetated areas on the edges of the gravel berm may
also be colonized by meadow or singing voles and some
species of shrews.
Portions of the road will likely cause subtle changes in
drainage patterns in lateral areas which in turn may result
in alterations to vegetation.The types of vegetation that
become established will depend on whether water levels in-
crease or decrease as a result of the road.Species compo-
sition of small mammals in these areas will shift according-
ly,with brown lemmings,bog lemmings,and tundra voles
preferring the wetter areas;and red-backed voles,singing
voles,and shrews attracted to the well-drained areas.
4.3.4 -Transmission Lines
The construction and operation of the transmission lines associa-
ted with the project will impact a wide variety of wildlife.The
four segments of transmission lines--Cook Inlet-to-Willow,Healy-
to-Fa i rbanks,Wi 11 ow-to-Healy (the Interti e),and Watana-to-the
Intertie--extend over 350 miles (563 km),traversing habitats
ranging from closed forests to tundra (see Table E.3.86.Several
types of impacts can be expected,including habitat
E-3-492
--
-
4.3 -Impacts -Access
alterations,disturbance during construction,direct impacts
caused by the presence of the transmission lines,and indirect
impacts resulting from improved access (see Section 4.3.3).
The cleared width of the corridor will be 300 feet (91.4 m)for 2
towers,400 feet (121.9 m)for 3 towers,and 510 feet (155.4 m)
for 4 towers (Figure E.3.85).Between Watana and the intertie,a
2-tower corridor will be cleared.With the addition of Devil
Canyon power,a 2-tower corridor will be cleared from the Dev'll
Canyon powerho,use to the Watana-Intertie line and the existing 2
tower corridor from that junction to the intertie (12.9 km)will
be widened to 4 towers.From the junction with the intertie
north to Healy,the intertie will be widened from 1 to 2 towers.
From Healy,a new tower corridor,paralleling the old corridor,
will be cleared to the Ester substation near Fairbanks.From the
junction ,with the intertie south to Anchorage,the existing
corridor wi 11 be widened from 1 to 3 towers.A map of the
transmission corridor route appears on Figure E.3.37.Initial
clearing will be done with a hydro-ax or other mechanical equip-
ment.Vegetation will be cut to 6 inches for most of the corri-
dor,as described in Section 3.4.2 and 3.4.3 (Figure E.3.85).
Clipped vegetation will be stockpiled,then hauled to another
site for burning or disposal.The vegetation will be maintained
periodically by repeating these measures.
In general,the transmission corridor will impact local wildlife
through disturbance during clearing,which will occur periodical-
ly throughout the 1 He of the project and through habitat al tera-
tion.Disturbance is most likely to have a serious impact on
nesting bi rds.,parti cul arly raptors near the corridor and
raptors,small mammals,small terrestrial birds,and waterfowl
which may suffer nest destruction within the cleared areas.
Larger mammal s which are sensitive to disturbance may avoid the
corridor during clearing operations in areas where it overlaps
their range (see sections below)but are unlikely to suffer any
serious impacts.Moose calving concentrations and bear den
sites,if they occur in the corridor,would be the most sensitive
areas.Vegetation within the corridor will be maintained at
early successional stages by periodic cl ipping.Areas of various
vegetation types which will be altered by transmission corridor
clearing appear in Tables E.3.35 through E.3.36.This will cause
local alterations in home ranges of small species which are rest-
ricted to closed forests where they overlap the corridor.Large
bodied,more mobile species,will be less affected.Many species
will benefit from the vegetation diversity which the corridor
will provide.Small mammals (particularly voles)are likely to
colonize the corridor and will provide an easily accessible prey
for some raptor species.Small birds which will colonize the
E-3-493
4.3 -Impacts -Transmission Lines
corridor will also provide accessible prey for raptors.Moose
and black bear will also experience positive impacts.
(a)Big Game
(i)Cook Inlet to Willow
The southernmost segment of the transmissi on corri-
dor,from Cook Inlet to Willow,traverses mostly
forest vegetation types (Table E.3.86).The most
common community types are closed and open mixed
forest and closed birch forest.The big game species
that are most likely to be affected by the clearing
of these forest types are moose and black bears.
Both of these species utilize browse in early-to-mid-
successional stands,and would likely benefit from
the vegetative communities present in the trans-
mission corridor after clearing (Scotter 1971,
Lindzey and Meslow 1977).There are little data
quantifying the effects of such clearings in terms of
population productivity,but the general conclusion
is that transmission line clearing should increase
carryi ng capacity for moose and bl ack bears (Sopuck
et al.1979).
The disturbances caused by human activities during
construction will be temporary effects.Most big
game animal swill relocate duri ng the construction
phase,but are expected to return once construct ion
is completed (Commonwealth 1982).Serious impacts
are expected only if clearing and construction occur
near moose calving grounds or bear denning sites.
Disturbance of animals at such sites could cause
decreases in productivity.The increase in human
activity in the area between Willow-Cook Inlet during
the construction of the transmission line is unlikely
to affect regional distribution of big game species.
This area is already subject to high levels of human
activity.The most abundant big game species--moose
and black bear--are fairly tolerant of human distur-
bance;those species easily disturbed (i.e.,wolf,
wolverine,brown bear)are already rare in the area.
(ii)Healy to Fairbanks
The transmission line right-of-way in this area will
traverse mostly open spruce forests,along with mixed
low shrub,open mixed forest,and open deciduous
forest (Table E.3.86).In all cases,community types
E-3-494
,"C'.,
4.3 -Impacts -Transmission Lines
that will be affected by clearing operations are
widespread and abundant in the area.
Impacts are expected to be similar to those discussed
in the Cook Inlet to Willow section above.Most of
the direct impacts will occur during the construction
period,when disturbance will cause big game species
to relocate.After construction,moose and bears are
expected to benefit from the early successional com-
munities along the corridor.The other big game
species are uncommon in this area.
-
(iii)
(iv)
Willow to Healy
The transmission corridor from Willow to Healy (the
intertie)will have to be widened to accommodate the
power from the Susitna project.Most of the intertie
is located in forest types:bottomland,lowland,and
upland spruce-hardwood forests (Commonwealth 1982).
The additional clearing required will affect local
populations of moose,caribou,Dall sheep,brown
bears,and black bears.Animals that relocate
because of di sturbance from construction activities
can be expectedto return.
Most of the major impacts associated with trans-
mission corridors (discussed in the preceding
sections)will al ready be effective because of the
existence of the intertie.Thus,the modification
requi red for the Susitna project is not expected to
increase access,hunting,or long-term human distur-
bance levels.
Watana Dam to the Intertie
The transmi ss ion corridor from Watana dam to the
intertie traverses mixed spruce-hardwood forests and
brush communities,paralleling the road and railroad
access routes (Table E.3.85).Clearing required in
forested areas will probably have a beneficial effect
on black bear and moose.
(b)Furbearers
Furbearers will be affected by construction of transmission
lines caused by habitat al teration and increased trapping
pressure resulti ng from improved access.Although it has
been shown that clear-cut areas are not a barrier to travel
E-3-495 I
4.3 -Impacts -Transmission Lines
by short-tailed weasel,least weasel,mink,marten,or other
muste1ids,cleared areas are usually not used for hunting
(Soutiere 1978),and some furbearers may avoid disturbed
areas.Forested areas offer better sub-nivian hunting con-
ditions because the bases of trees,logs,and windfalls
provide numerous entry points (Koehler et a1.1975).
Forested habitat supporting approximately 6 marten (see
winter model,Section 4.3.1 em])will be cleared for the
transmission corridor.
Foxes and coyotes are sometimes attracted to cleared areas
as movement corridors (Penner 1976).Both foxes and coyotes
may benefit from the removal of forest vegetation,since
they feed heavily on microtine rodents.
Transmission lines will increase access for trappers and
could result in local population reductions of some furbear-
ers,particularly in presently remote areas.Marten and
beaver will probably suffer the greatest impact,since they
are currently the target of most trapper effort.
The impact of trapping on coyote,red fox,and lynx will
probably be less severe,since they are wider ranging than
the smaller muste1ids.Least weasels,short-tailed weasels,
and mink have historically received little trapping pres-
sure.
(c)Bi rds
The construction and operation of the transmission corridors
wi 11 affect bi rds mostly as a resu1 t of changes in vegeta-
tion height,disturbance during initial construction and
maintenance,and the electrocution or collision mortality of
large raptors and swans from transmission wires.Since much
of the transmission corridor passes through forest,forest
species will be replaced by birds of shrub and open habitat.
Species diversity may also change (see Section 4.3.1 [p][i]
-Habitat Alteration.
Currently,there are no transmission lines in the vicinity
of the project (the nearest comparable lines occur between
Anchorage and Willow,and between Healy and Fairbanks).
Although no studi es have been conducted and no data are
currently available regarding incidents of bird collisions
or electrocutions with these transmission lines,shorebirds
have collided with various kinds of guy wires in western
coasta 1 Alaska du ri ng foggy weather (Gi bson 1982 personal
communication),and collisions of birds (especially water-
fowl)with overhead ground wires have been documented
E-3-496
-
-
-
4.3 -Impacts -Transmission Lines
elsewhere in North America (James and Haak 1979).Among
waterfowl,swans are particularly susceptible to collisions
with power lines (Avery et al 1980).In general,bird
collisions with transmission lines are difficult to prevent
(marking lines may minimize collisons to some extent),but
also tend to be biologically insignificant (James and Haak
1979).
Bi rds of prey are suscept ibl e to el ectrocuti on as a resul t
of perching on the structures (Harrison 1963).Electrocu-
tion is the greatest potential impact of power lines on both
raptors and ravens.However,the selected transmission
tower and line configuration is such that little possibility
for bird electrocution exists.However,the possibility of
electrocution still exists along the single 34 kv construc-
tion transmission line to be built from Cantwell to Watana
via the Denali Highway.Larger size is the greatest factor
affecting species vulnerability to electrocution (Oldendorff
et al.1981).Consequently,golden and bald eagles are the
most susceptible of the raptors inhabiting the area being
considered.In addition,immature or subadu1t eagles are
more susceptible to electrocution than adults.Buteos
(e.g.,red-tailed hawk and rough-legged hawk)are also
vulnerable,but accipiters (e.g.,goshawk and sharp-skinned
hawks)and even the larger falcons (e.g.,peregrines and
gyrfa1 cons)are rarely el ectrocuted (01 endorff et a1.
1981).
Only one known raptor nest occu rs near the proposed trans-
mission route,but this nest is of special concern because
it was once occupi ed by peregri ne falcons,an endangered
species.The nest occurs along the Tanana River on the east
side of the corridor between Healy and Fairbanks.This nest
was first discovered in the early 1960s,but was inactive in
the early 1970s (Roseneau 1982 personal communication).It
was checked by the u.s.Fish and Wildlife Service in 1982
and was also inactive that year (Amaral 1982 personal
communication).Whether or not it will be used again is
unknown.If the nest is active during the construction of
the 1i ne,the bi r.ds may abandon it as a resu1 t of the
disturbance.If the nest remains inactive during line
construction,however,it will most likely be acceptable for
1 ater use duri ng the operat i ona 1 phase of the the 1i nee If
necessary,the transmission line in this area could be
constructed during a time period that would reduce the like-
lihood of disturbing nesting peregrines.Furthermore,a
Section 7 consultation,as required by the Endangered
Species Act,will be conducted with the U.S.Fish and
Wildlife Service to help insure that the peregrine nest is
not affected.
E-3-497
4.3 Impact s Tr ansmi ssi on Li nes
Potenti al di sturbance to bald eagles as a result of
constructi on and mai ntenance of the i nterti e li ne between
Wi 11 ow and the Gold Creek Switching Station wi 11 probably be
minimal because the majority of the known nesting locations
and nesting habitat occur along the banks and on the islands
of the Susitna River (Table E.3.129).However,at least
three nesti ng locati ons occur 1 mi le (1.6 km)or less from
the corri dor,and veri fi cati ons of more accurate di stances
will be made to identify locales where mitigation may be
necessary.Although no nests of bald eagles are known to
occur in the immediate vicinity of the corridor centerline,
some potenti al bald eagle nesti ng habi tat may be lost as a
result of clearing balsam poplar and white spruce trees in
some sections of the proposed line.
Potenti al di sturbance wi 11 be mi ni mal to golden eagles and
gyrfalcons as a result of constructi on and mai ntenance of
the intertie line between the Gold Creek Switching Station
and Healy.No known nesting locations or nesting cliffs
occur in the valley bottom along the proposed route.All
known nests and nesting habitat are at elevations well above
the valley floor.Although no nests of bald eagles are
known to occur along the route north of the mouth of
Indi an Ri ver,some nesti ng habitat may be lost as a result
of clearing poplar trees in some areas between Chulitna,
Butte,and Hurricane.
Minimal disturbance of raptors and ravens in the study area
isanti ci pated as a result of constructi on of the hi qh vol-
tage transmi ssi on li nes between the Watana dam and the
i nterti e.Only one golden eagle and two raven nesti ng loca-
tions may be susceptible (GE-18,R-13,and R-21;see Table
E.3.160).Potenti al for di sturbance as a result of summer
constructi on would be greatest at GE-18 and R-21 if these
nesting locations were active in the year when construction
occurred.However,this potential impact,although addi-
tive,is considered far less severe than the longer term
potenti al impacts associ ated wi th nearby dam constructi on
upriver and bridge construction and associ ated traffic down-
river from GE-18 and R-21.
Table E.3.71.5 indicates an order-of-magnitude of 655 of
1,200 small to medium-sized breeding birds lost to the
transmission line,less than 0.1 percent of the population
within 16 km of the Susitna ~ver between the McLaren ~ver
and Go ld Creek.
£-3-498
4.3 -Impacts -Summary
,....
(d)Non-game (small)Mammals
The transmission lines for the Susitna project will traverse
a wide variety of small mammal habitats.These transmission
corridors will be cleared of trees and tall shrubs.Because
most small mammals are ecotone species,they are expected to
benefit from the edge effects created by the clearings.One
example is the snowshoe hare,which relies on dense black
spruce forests for cover,but prefers more open areas for
forage (Kessel et a1.1982a).Overall,transmission
corri dors are not expected to adversely impact sma 11
mammals.
-I
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4.3.5 -Impact Summary
This section summarizes those impacts on wildlife populations
predicted to be of sufficient magnitude to influence mitigation
planning.The emphasis is concentrated on what are considered to
be the most seri ous impacts to wil d1 He popu1 ati on 1eve1 s;both
positive and negative impacts are discussed.
Whether impacts to wildlife are judged to be positive or negative
depends on the perspective of judgment.For examp1 e,increased
access by hunters and trappers usually depresses population
levels of big game species and furbearers.But at the same time,
increased access has the potenti a1 to increase the long-term
yield and value of this wildlife to consumptive users.
Herein we address impacts only from the perspective of the wild-
life populations per see An increase in wildlife abundance or
production is a positive impact;a decrease in wildlife abundance
or production is a negative impact.Project actions known or
specul ated to cause measurab1 e changes in project area wi 1d1 i fe
population or production levels are discussed,but those actions
thought to cause negligible or no changes are not.
(a)Big Game
The bi g game popu1 ati ons expected to be affected by the
Susitna project are moose,black bear,brown bear,wolf,
wolverine,Dall sheep,and caribou.The main effect on
these species will be through habitat loss by "inundation,
interference with movements,habitat alteration,distur-
bance,collision mortality,increased necessity for killing
nuisance animals,and increased access afforded to hunters.
Moose will be most severely affected by habitat loss caused
by i nundat i on of spri ng and wi nter range.In wi nters of
relatively light snowfall (i.e.,less than 30 inches),
approxi mate1y 300 moose occur in the impoundment zones.A
prel imi nary estimate of wi nter carryi ng capacity for the
E-3-499
4.3 -Impacts -Summary
Watana impoundment zone is 301 resident moose (see Appendix
3.H).However,when snow depths exceed 30 inches,much
higher numbers of moose are expected to move to the impound-
ment zones (ADF&G 1982a).The effects of habitat loss on
moose are being addressed through continuing studies and
through the development of a habitat-based model of carrying
capacity.
Moose displaced from the impoundment zones will compete for
food and space with other moose.The consequences of thi s
competition could seriously reduce the carrying capacity of
adjacent range with potential long-term effects on mortal-
ity rates,predator populations,and natality.The computer
model bei ng developed wi 11 be used to determi ne whether
adjacent areas can support these additional moose (see
Section 4.3.1[a][iii]and Section 4.4.2[b]Mitigation Plan
6.Borrow sites,camps,and the airstrip at Watana will
remove winter habitat for about 37 moose.These areas will
revegetate after construction,but p1 ant growth where top-
soi 1 has been removed wi 11 be very slow.Transmi ssi on
corridors contain browse supplies that will support 47 moose
for 180 winter days.The growth of vegetation between years
of vegetation maintenance (clearing)will compensate for the
loss just after clearing.
The reduced summer f1 ows and increased wi nter flows will
alter the distribution of floodplain communities downstream
from Devil Canyon.When Watana only is operating,the width
of the un vegetated floodplain between Devil Canyon and
Talkeetna will inc.rease,but with both dams,some of the
floodplain will be recolonized by vegetation.The open
water in winter from Devil Canyon to Talkeetna (both dams)
will make much of this vegetation unavailable because moose
will not cross the open water to islands and heavy frosting
will cover vegetation near the river.Changes downstream
from Talkeetna cannot be predicted because vegetation
patterns wi 11 be i nf1 uenced by snow depths each wi nter,by
the speed of spri ng breakup,by flow re1 eases as they are
affected by power demand,and by river morphology along the
various reaches.Because large numbers of moose (over 1000
in 1982)move to the lower river floodplain,small changes
in vegetation patterns could have an adverse affect.
Disturbance and altered movement patterns are un1 ike1y to
have detectable population-level effects.Some calving
areas (on islands downstream from the project area to
Tal keetna)may become unava i1ab 1e because of open water.
However,moose are capable of altering habitual movement
patterns to adapt to such changes in range,and no long-term
E-3-500
..-
4.3 -Impacts -Summary
population-level effects are anticipated to result from
construction-related disturbances or altered movements.
The consequences of increased moose mortality caused by
impoundment hazards,collisions with trains and vehicles,
and increased predation levels are being explored through
the use of computer model i ng.These factors alone are
likely to have a much lesser effect on moose than will
habitat.loss.However,their cumulative effects with
habitat loss and reduction in carrying capacity of adjacent
range may be severe.
The Ne1china caribou herd will be most affected by interfer-
ence with movements across the impoundment zone and access
road.At the current herd size,no population-level effect
is likely to be detected during the construction period.but
the access road may block the movements of 90 percent or
more of those caribou which may attempt to cross,thus
isolating the mountains north of the river and west of the
road from the remai nder of the herd I s range.As the herd
increases,the importance of thi s hi stori cally used range
will increase and the loss of areas to the west of the road
may decrease the carryi ng capacity of the range by up to 10
percent.Caribou cows with calves may avoid the road,but
no direct effect on productivity or survival of calves is
expected.
The Devil Canyon impoundment and transmi ssi on 1i nes wi 11
have little effect on caribou.The Watana impoundment,how-
ever,will alter caribou movements and may result in cross-
ing mortalities because of hazardous ice conditions or
floating debris.The potential for increased mortality can-
not be predicted,since ice conditions will vary each year
and the number of car-j bou crossi ng the impoundment as the
herd expands is unknown.
Increased recreational use of the area may become a severe
impact.The calving area and summer range of females with
calves would be most sensitive.Heavy use of widespread
areas by all-terrain vehicles would also seriously reduce
carryi ng capacity through vegetati on damage.Although no
quantification is possible,the cumulative effects of
intense and unpredi cab1 e recreati ona1 di sturbance on the
historically used calving ground and the potential loss of
some portions of the range due to blocked access in concert
with increased mortality during migration across the Watana
impoundment may constitute a severe impact.
E-3-501
4.3 -Impacts -Summary
The ADF&G has expressed concern that impacts with no
measureable effect on current population levels may nonthe-
less further reduce the ratio of harvest to demand,which is
already low,by eliminating the option to allow a substan-
tial increase in herd size for that reason.
Dall sheep will be affected primarily by partial inundation
and di sturbance at the Jay Creek mi neral 1i ck.Oi sturbance
anticipated is mostly recreational,both during and after
the construction phase,and from low-flying aircraft.The
consequences of sheep abandoni ng the Jay Creek 1i ck are
unclear.Several other licks occur within the range of the
Watana Hills population,but because sheep show high fideli-
ty to particular areas,it is not known if these licks would
replace Jay Creek.
Brown bears will lose important spring feeding areas to the
impoundment zones and will al so be adversely affected by
lower numbers of moose.Sows wi th cubs do not use the
impoundment zones but about half of the remaining radio-
collared bears moved there in spring during recent studies.
During the construction phase,a number of bears may be
killed for safety reasons or may die after being disturbed
from wi nter dens by peopl e on the ground or in 1ow-flyi ng
aircraft.In addition,bear/human conflicts have a great
potential to cause significant loss of work time for con-
tractors,injuries to employees,and property damage.No
denning areas will be flooded by the impoundments.
The reservoir may alter the movements of brown bears between
seasonally important food sources,particularly when float-
ing ice or debris are present.Because the relationship
between brown bear foods and population levels is poorly
understood,the impact of the project on brown bear carrying
capacity cannot be predi cted.The effect of reducti ons in
salmon spawning between Portage Creek and Talkeetna similar-
ly cannot be predicted.
Management strategies and priorities beyond the control of
the Power Authority will determi ne to what extent hunti ng
and poaching become severe mortality sources.Historically,
brown bear have been -sacrificed to the benefit of ungulate
species more desirable to subsistence users by management
guidelines.
Black bears will be severely affected by the project,
prima rily as a result of i nundat i on of denni ng and feedi ng
habitat upstream from Tsusena Creek.The Watana reservoi r
E-3-502
r'C"
-
"...
4.3 -Impact s -Summa ry
will inundate approximately 69 percent of the denning habi-
tat occurring in that area (black bears are restricted to
the band of forest along the river),whereas about 6 percent
of the denning habitat in the Devil Canyon reservoir vicini-
ty will be lost.Additional denning areas will be impacted
by road and ,transmission line construction.The resident
population of about 30-50 bears between the Tyone River and
Tsusena Creek will probably be e1 imi nated.Bears residi ng
downstream from Tsusena Creek may a1 so be affected by pro-
ject facilities near Watana interfering with movements up-
stream in summer.As discussed for brown bear,the effects
of possibly reduced salmon runs downstream from Portage
Creek and disturbance from recreational users during salmon
runs on the black bear population cannot be quantified.
Cumul ati ve impacts of morta 1ity from hunti ng increased
encounters with brown bears and bear/human conflicts in
concert with loss of denni ng and feedi ng habitats due to
facil iti es and di sturbance wi 11 greatly reduce the bl ack
bear population in the middle basin.
Wolf popu1 at ions are cur rent1y cont roll ed by human harvest
levels (much of it illegal),and the reduction in moose
numbers will not be a major factor under these conditions.
Improved access in the proj ect area may result in even
heavier exploitation of wolves.If wolf survival greatly
increases because of better enforcement and management,the
lower prey base may affect as many as 10 wolf packs in the
project area.The Watana pack will be seriously reduced and
possibly e1imi nated due to loss of hunti ng areas and reduced
moose populations.Immedi ately foll owi ng fill i ng of the
Watana reservoir displaced moose will be more vulnerable to
predati on.Impoundment hazards and the advantages conferred
on predators along the impoundment shore1 i ne will a1 so act
to increase the availability of prey.However,the 10ng-
term effects of the impoundment are more likely to result in
a reduced availability of prey for the Watana pack.Winter
availability of caribou to individual wolf packs varies year
to year.However,no net decrease in availability of cari-
bou to the wolves of the mi dd1 e bas in isanti ci pated.The
above discussion of caribou trials the elimination of a
management option for substantially increasing herd size to
allow greater satisfaction for subsistence users.Although
this also eliminates the option of .substantially greater
wolf populations,those management goals would conflict with
thi s eventual ity anyway.The extent to whi ch increased
access and use of the middle basin reduces wolf populations
depends almost entirely on management priorities of the
Alaska Department of Fish and Game and is beyond the control
of the Alaska Power Authority.Because wolves are uncommon
E-3-S03
4.3 -Impacts -Summary
downstream from Devil Canyons changes in moose numbers there
are unlikely to have any effects.
Wol veri ne wi 11 be affected primarily by improved access for
trappers.Habitat supporting about two wolverine will be
lost to the project.Additional temporary loss of habitat
due to both construction related and recreational distur-
bance is possible but likely to affect only small areas of
the territories of a few individuals.Higher turnover rates
hypothesized for moose populations would result in increased
availability of carrion.Overall s changes in wolverine
populations will be difficult to detect due to naturally low
density and dispersal from surrounding productive habitat.
Bel ukha whal es wi 11 not be measurably affected by the pro-
ject at any time of the year.
(b)Furbearers
Overall s beavers are expected to benefit from the project
because of regulated flows in downstream reaches,but local
populations will be adversely affected during road and dam
constructions and many will be vulnerable to increased trap-
pi ng because of improved access.Approximately 40 beavers
now occupy sections of Deadman Creek designated as borrow
sites for road construction.No beavers reside in the
impoundment areas,but the lakes in and adjacent to Borrow
Site K at Devi 1 Canyon support approximately 10 beavers.
There are approximately 25 beavers along Jack Long Creek;
these beavers could be adversely affected by increased silt-
ation or clearing of riparian vegetation during construction
of the railroad and staging area.In totals about 75
beavers will be lost to the project during its construction.
It is not known if improved habitat downstream will compen-
sate for this loss without enhancement.
Habitat improvements anticipated for beaver in downstream
reaches include:an increase in availability of suitable
overwintering sites caused by increased flow (Leos deeper
water preventing freeze out),greater stability in anchoring
food caches due to stabi 1i zed flows sand ava i1abi 1i lty of
shallower sites than are currently used for overwintering
because of open water.A beaver habitat model is being
developed to assist in impact assessment and mitigation
planning.This model incorporates data on river f10ws s
water temperatures s depth of water under the ices
vegetations bank substrates s and beaver populations with
various flow releases and trapper effort.
E-3-504
....
i
r
--
4.3 -Impacts -Summary
The project will have an insignificant effect on muskrat,
except that improved access may result in overtrappi ng of
some areas.No muskrat occuri n lakes to be used as borrow
sites or other facilities,but 5 lakes within the impound-
ment zone (on lower Watana Creek)are occupied by muskrats.
Approximately 5-10 muskrats will be lost because of impound-
ment fi 11 i ng and constructi on.Improved habitat for beaver
downstream from the dams will also have a beneficial effect
on muskrat,and should easily compensate for the minor loss
of habitat within the impoundment.
Mi nk and otter will be adversely affected by cl eari ng and
inundation of the impoundment areas,removal of road-build-
ing materials from Deadman Creek and wetland areas,and by
increased trapping pressure.Both mink and otter are some-
what sensitive to disturbance and may suffer significantly
from increased presence of fi shermen and recreat i ona 1 users
in remaining river habitat.Assuming that all habitat along
the mainstem upstream from Gold Creek and its tributaries
supports equal densities of mink and otter,about 21 percent
of the river and stream habitat of these species wi 11 be
lost.Few impacts on lakes and ponds will occur.Regulated
flows are expected to improve downstream habitat for these
species,and the stable water level on the Devil Canyon
reservoir during most of the year will probably allow these
species to reside there.
All upland furbearer populations are expected to decline for
two main reasuns--i nun dati on of porti ons of thei r habitats
by impoundments,and increased trappi ng pressure caused by
easier trapper access.
Coyotes are uncommon upstream from Devi 1 Canyon and are
likely to remain so;the impact on this species will be
negligible throughout the project area.Increases in
numbers of coyotes would be anticipated only if wolves are
severely reduced or eliminated.Red foxes will be adversely
affected by loss of habitat in the impoundment area,
habituation to human activity along the roads and at camps
and 1andfi 11 s,and by increased trappi ng pressure.The
access roads occur within 0.5 mile of several large red fox
denning complexes,and local overharvesting of foxes may
occu r.Because foxes den and feed primarily at el evati ons
above the impoundment level,major population effects due to
habitat loss are not anticipated.Di rect mortal ity caused
by trapping and the killing of nuisance animals is likely to
have a significant population level effect.
E-3-505
4.3 -Impacts -Summary
Marten will be the most severely affected furbearer species.
Habitat supporting approximately 100 marten will be lost to
the Watana reservoi r;the Devi 1 Canyon reservoi r contains
habitat supporting about 21 marten;and forested areas
supporting about 6 marten will be cleared for transmission
corridors.In total,habitat supporting approximately 130
marten will be lost to the project.Although improved
access may allow a higher trapping yield from the remaining
population,local overharvesting of marten in some areas may
occur.Major impacts on lynx,short-tail ed weasel,and
least weasel are not expected.
(c)Birds and Non-game Mammals
Birds will be affected primarily by habitat loss to inunda-
tion and disturbance of nests.Sixty-three to sixty-eight
percent of the known raptor cliff-nesting locations in the
middle and upper basins and 70 percent of the known raptor
tree-nesting locations will be affected by the project.
This includes over half of the golden eagle nests,75 per-
cent of the bald eagle nests,33 percent of the gyrfalcon
nests,and 66 percent of the known goshawk nests (Tab 1e
E.3.160).Raptors downstream from Gold Creek will not be
affected,except in a few cases where construction of trans-
mission lines disturbs raptors at their nests.Small
numbers of raptors may be lost as a result of electrocution
along power lines.
Waterbi rds of 1acustri ne habitats wi 11 suffer only mi nor
impacts,since only 38 ha of lakes and ponds will be flood-
ed.Trumpeter swans which nest o'n lakes near the project
area may be adversely affected by low-flying aircraft.Most
swan nests are some distance to the east of project facili-
ties and no disturbance is anticipated.Birds of fluviatile
habitats will suffer a significant loss of habitat.Breed-
i ng habitat for spotted sandpi per,mew gull,harl equi n
duck,common and red-breasted merganser,semipalinated
plover,wandering tattler,and arctic tern will be lost.
Additi anal losses of breedi ng habitat in forests will occur
for goldeneyes and lesser yellowlegs.Sandbars,islands and
riparian shoreline areas used for feeding,roosting and
loafing by shorebirds will be flooded.River and stream
flooding habitat for breeding dippers,mergansers,harlequin
ducks and gal deneyes will be lost.A1though the mi ddl e
basi n is not a mi grati on corri dor,the open water areas
withi n the impoundments wi 11 be used for 1eafi ng by early
mi grants before other waterbodi es are open.The drawdown
zones will be used as 1oafi ng habitat for mi grant
shorebirds,but food availability will be low.The
E-3-506
'"'"'
.....
-
..-
4.3 -Impacts -Summary
impoundments are likely to offer very few food resources to
migrants or residents,although low densities of fish and
invertebrate prey wi 11 be present.Open-water areas down-
stream from the dams may benefit migrant waterfowl and
shorebi rds and provide wi nter habitat for the di pper.
A1though the 1arge impoundments wi 11 greatly increase in
surface area of water in the middle basin,the drawdown of
the \~atana reservoir will minimize its importance as lacus-
trine habitat.The Devil Canyon impoundment will be more
appropriate lake habitat,although recreational boating will
limit its use for shoreline nesters.
Populations of small and medium sized birds within 16 km of
the Susitna River between the McLaren River and Gold Creek
will be reduced by 5 to 17 percent for most species and the
total number of breeding terestrial birds lost will approach
103,000.Proportionate losses are greatest for birds
rest ri cted to fo rest habitats,and over 12 percent of the
populations within 16 km of the river of the following
species will be lost:spruce grouse 16 percent),hairy
woodpecker 16 percent),northern three-toed woodpecker 12
percent,brown cree er 16 percent,varied thrust 12
ercent,Swainson s Thrush 12 percent,yellow-rumped
warbler 13 ercent ,and northern waterthrush 16 percent.
Largest numerical losses will be for species which are found
at high densities in a range of vegetation types:yell ow-
rumped warbler 13,020,tree sparrow 10,112),dark-eyed
junco 7,990,Swainson1s Huush 7,062,Wilson1s warbler
6,760 ,savannah sparrow 6,150,fox sparrow 6)060,and
white-crowned s arrow 5,992.Habitat alteration will
affect the distribution and abundance of species,again with
birds restricted to closed forest habitats suffering losses,
while species associated with edge disturbed,or artificial
habitats wi 11 benefit.The increase in amount of edge may
increase species diversity and density in localized areas.
Bank and cliff swallows and kingfishers will experience
increases in availability of nesting habitats.Ravens and
gulls are likely to increase in numbers in the basin,parti-
cularly if refuse dumps are not adequately maintained.
Only those species of small mammals which are restricted to
forest habitats are 'expected to experi ence a decrease in
regional abundance.Porcupines,snowshoe hares,pygmy
shrews and red squi rrel s wi 11 be most affected.Al though
they are found in nearly every vegetation type in the Watana
area,red-backed voles are most common in spruce and cotton-
wood forests and will suffer a decrease of up to 5 percent
in the basin population.Meadow voles may actually increase
in the basin due to the appearance of disturbed and
reregul ated areas.The major impact of the projects on
small mammals will be local alterations in the distribution
and abundance of species.
E-3-507
4.4 -Mitigation Plan
This mitigation plan has been developed for impacts likely to have
population-level effects on important species in accordance with the
approach outlined in Sections 1.2 and 1.3.As discussed in those
sections,mitigative measures have been prioritized as follows:avoid-
ance,mi ni mi zati on,recti fi cati on,reducti on,and compensati on.Avoi d-
ance and mi ni mi zat i on of imp act s are best achi eved by i ncorpor at i ng
envi ronmental cri teri a into preconstructi on pl anni ng and desi gn and by
modifying certain construction practices.In many cases,measures to
avoid,minimize,or rectify impacts to wildlife are identical to the
preferred measures for mitigating impacts to botanical resources.The
mitigation plan for botanical resources (Section 3.4.2)discussed modi-
fications to engineering des\gn and construction planning for environ-
mental reasons,such as changes in the ali gnment of access roads and
t ransmi ssi on corri dors;avoi dance of cert ai n ri pari an areas for gravel
extraction,consolidation,and resiting of certain project faci lities;
and rehabi litati on of temporary constructi on sites.Si nce botani cal
resources assume thei r greatest importance as wi ldli fe habitat,the
wi ldlife and botanical resources mitigation plans complement each
other.Measures discussed in the botanical resources plan that also
apply to wi ldlife mitigation are repeated only in appropriate cases.
Field studies sponsored by the Power Authority are continuing to refine
and quanti fy the results from three years of baseli ne and impact re-
search.As addi ti onal i nformati on from these conti nui ng studi es be-
comes available,certain concepts contained in this mitigation plan
wi 11 be refined to specify the number,location,and design of mitiga-
t i on feat ures.
The impact summary (Section 4.3.5)describes the impacts and criteria
used to identify impacts requiring mitigation.Impact issues are
treated here in three categories:(I)impact mechanisms resulting in
reduction in carrying capacity;(2)impact mechanisms which increase
mortality,thereby altering population structure and the ability of
populations to recover from other secondary impacts or natural mortal-
ity phenomena;(3)disturbance.Impact issues deflned in Section 4.3
as habitat loss,habitat alteration,and barriers to movement represent
effecti ve habi tat loss and are treated as mechani sms resulti ng in re-
duced carryi ng capacity.An analysi s of miti gati on opti ons is pre-
sented for each species or group for each mechanism.Separate mitiga-
tion plans are then presented wh\ch may apply to an individual species
or group (Section 4.4.2).A cost analysis and schedule for mitigation
appear in Section 4.4.3,and Section 4.4.4 documents all agency recom-
mendations for mitigation.
4.4 -Miti gati on Pl an
4.4.1 -Impact Issues and Option Analysis
The following discussion presents an analysis of mitigation
options for each impact.The options to be implemented are
E-3-508
4.4 -Hi ti gat i on Plan
-
detailed in Secti on 4.4.2,and an ana1ysi s of resi dual
impacts with the chosen mitigation plans appears in Section
4.4.3.
(a)Reducti on in Carryi ng Capacity
(i)Moose
-
Project impacts on upstream habitat will reduce
carrying capaci ty through i nundati on of spri ng and
winter range.Approximately 37,502 acres (15,177 hal
of vegetated habitat will be permanently lost to fa-
ci 1i ti es and impoundments for both projects.Thi s
represents wi nter habi tat for 302 moose based on
carrying capacity estimates presented in Table E.3.92
and Appendi x 3.H.The wi nter carryi ng capaci ty of
the Watana permanent fact 1i ti es is 266 moose;that
for Devi 1 Canyon is an addi ti ona1 36.Addi ti ona1
habitat a1terati on due to temporary faci 1iti es and
borrow sites (4532 acres [1875 ha])wi 11 bri ng the
total affected area to 42,135 acres (17,052 hal in
.-the immediate victnity of the impoundments.The
total carryi ng capacity of these areas is 340 moose.
The no-project option is the only means of avoiding
this impact.
The impoundment zones may be important as a source of
early spring foods and as calving areas,and also as
wi nter range for moose (ADF&G 1982a).Thei r loss
could be temporarily avoided by delaying c1ear'jng of
the impoundment areas.However,the impoundment
zones must be cleared to avoid producing large quan-
titi es of timber debri s on the reservoi rs.Habitat
t 10!iS;:~U'I:.l~e of clearing could be minimized by:(1)
f,,"stnedu1i ng/c1eari ng as close to reservoi r,..-f-H"li-rrg-.~.~s
~le;(2)leaving relatively 1arda_"is1and~11
of riparl.an-··\Le.g.et.at.i,pn uncleared;and/or {3r-crear-
'I i ng l5nly trees and tall shrubs,leavi ng the browse
!species preferred by moose .
.To reduce vehicle traffic and impacts to other areas,
it is preferable to burn the cleared vegetation in
place rather than to transport it to some other area.
In order to retain browse vegetation,the slash would
have to be burned in piles (rather than a broadcast
burn).The increased use of mac hi nery requi red for
pi ling may offset the benefits of preferential c1ear-
i ng of trees and tall shrubs.-
';pu.E-3-509
4.4 -Mitigation Plan
Temporary facilities during construction will remove
approximately 4532 acres (1875 ha)of vegetated habi-
tat.Avoidance is possible only by the no-project
alternati vee Mi nimi zati on is possi ble by usi ng si de-
borrow techni ques for road constructi on,whi ch wi 11
reduce the number of borrow sites,and by depositing
spoi 1 in the future impoundment areas or in depleted
borrow si tes.(Thi sis di scussed more fully in
Section 3.4.2.[a][i].)Further minimization is possi-
ble by consolidating facilities.Rectification is
possible through revegetation (Section 3.4.2[a][i]).
The vi llage and impoundments will permanently remove
about 37,502 acres (15,177 hal of vegetated habitat.
These faci lities are essenti al to the project,and
thus,thi s loss can be avoided only by not bui lding
the project.No measures to recti fy or reduce thi s
impact are feasi ble,and therefore,only compensati on
is feasi ble for miti gati on.
Clearing of vegetation in the transmission corridor
wi 11 result in habi tat alterati on.Thi s alterati on
cannot be completely avoided because some clearing
i s necessary to permi t constructi on to mi ni mi ze mai n-
tenance costs and to permit rapi d restorati on of
power in case of line breakage.Minimization could
be accomplished by aligning the corridor through tun-
dra types where possible and by designing the corri-
dor to leave as much shrub vegetation as possible.
Compensation for clearing could be provided by allow-
i ng shrubs and trees to grow between mai ntenance
clearing,which would maintain the corridor in early
seral stages preferred by moose.
Moose di spl aced from the impoundment zones duri ng
constructi on and fi lli ng wi 11 compete for food and
space with moose in adjacent areas.This may result
in overbrowsing of areas adjacent to the impoundments
and subsequently affect additional moose outside the
impoundment areas.Thi s impact woul d be avoi ded by
managing the moose population through a controlled
hunt of moose in excess of the carry;ng capaci ty.
It is unclear whether regulated flows wi 11 result in
a net increase or decrease in the amount of browse
available to moose in the Susitna floodplain down-
stream from the Devi 1 Canyon dam.However,because
the lower basin may support very high densities of
moose in some wi nters,a small decrease in browse
E-3-510
....
.....
-
4.4 -Mitigation Plan
avai labi lity could affect a ·large number of moose.
Additional impacts on browse avai labi lity and quality
wi 11 result from blockage of movements by open water
between Devi 1 Canyon and Talkeetna and possi ble
frosting of adjacent browse.
No measures are avai 1ab 1e to avoi d thi s impact.Mi n-
imization is possible through regulating river tem-
perature to maintain nearly normal ice conditions in
the lower reaches of the river.Rectification may be
pos~ble through controlled flow releases,river
training structures,and enhancement techniques.
Addi ti onal compensati on wi 11 occur because of the
increased avai 1abi li ty of wi nter browse whi ch wi 11
result from the constructi on and mai ntenance of the
transmission corridor.Much of the route is adjacent
to the river and wi 11 provide winter browse in areas
adjacent to those in which browse could be lost.
.....
(i i )Cari bou
The li kell hood of a reducti on in carryi ng capaci ty
caused by blockage of movements by the Watana im-
poundmentis unknown and undeterminable at current
population levels.If such an effect were demon-
strated,compensation would be the only feasible mit-
i gati on alternati ve.
The physi cal presence of the access road and the
vehi cle traffi c and other human acti viti es associ ated
with it wi 11 interfere with the movements of caribou,
particularly in the Denali Hi ghway to Watana section.
Avoidance of the road or failure to cross it would
result in habitat loss and decreased carrying capac-
i ty of the project area for cari bou.
This impact cannot be avoided except through the no-
project alternative.Minimization is poss'ible
through realignment to avoid the center of the calv-
ing ground and through design changes to minimize
physical and visual impacts (i .e.,side-borrow con-
structi on).Further mi ni mi zati on woul d be possi b1e
by regul ati ng traffi c on the road and by reduci ng
dust.No rectification is possible.Compensation
would be required if the access road is shown to af-
fect the si ze,producti vi ty,or di stri buti on of the
Nelchina herd .
E-3-511
4.4 -Mi t i gati on Plan
(iii)Da11 Sheep
Parti a1 inundation of the Jay Creek mineral lick and
blockage of access to the lick may reduce carrying
capacity of the area for Da 11 sheep.Up to 42 per-
cent of the surface area of the Jay Creek mi nera1
lick will be ~nundated each year by the Watana im-
poundment.Only 22 percent wi 11 be under water dur-
i ng May and June when sheep use of the 1i ck is great-
est.It is not known whether water in the reservoi r
will leach minerals from the lick soils and reduce
the value of the annually inundated portion to sheep.
However,the reserv~r may interfere with the move-
ments of sheep between the west and east side of the
creek.
No avoidance,minimization,rectification,or reduc-
tion is possible.Compensation may be provided by
exposing new mineral soi 1 at the lick site to replace
that possi b1y lost to 1eachi ng.
(i v)Brown Bears
Impoundment c1eari ng is necessary to e1imi nate debri s
on the impoundment surface.Th.e clearing of the im-
poundment zone and permanent f aci 1i ty areas wi 11 re-
duce the carryi ng capaci ty of the project area for
bears by eli mi nat i ng spri ng feedi ng areas and other
habi tats.Loss caused by c1eari ng could be mi nimi zed
(as descri bed for moose above)by:(1)scheduli ng
clearing as close to reservoir filling as feasible,
and/or (2)leaving large "is1ands"of riparian vege-
t ati on unc 1eared.
Temporary faci 1ities increase loss of habitat,but no
avoidance is possible.Minimization is possible
through use of si de-borrow techni ques for road con-
struction which reduce the number of borrow sites and
by deposi ti ng spoi 1 in the future impoundment or in
depleted borrow sites.Further minimization is poss-
ible by consolidating facilities.Rectification is
possible throagh revegetation.
Permanent habitat loss can be avoided only through
the no-project alternative.No measures to minimize,
recti fy,or reduce thi s impact are feasi b1e,and
therefore,compensation is the only mitigation alter-
native.
E-3-512
-
4.4 -Mitigation Plan
A reducti on in salmon spawni ng between Port age Creek
and Talkeetna has been identified as a possible fac-
tor which would reduce carrying capacity for brown
bear.This impact will be avoided through mainten-
ance of downstream sloughs for salmon spawni ng (see
Section 2.4.4 [aJ).
A reduction in ungulate prey is also hypothesized to
reduce carryi ng capacity for brown bear.Miti g ati on
measures proposed for ungulate populations wi 11
avoid,minimize,or compensate for this impact.
A possible secondary impact of the project on brown
bear is di spl acement from the Prai ri e Creek area,a
bear concentration area duri ng salmon runs.Project
access roads may accelerate mineral and recreational
developments in thi s area,maki ng confli cts wi th bear
use of this resource occur sooner than they would in
the absence of the project.This impact could be re-
d uced through cooperati vemanagement of development
and access by the Power Authority and resource agen-
ci es.
(v)Black Bears
Impacts of impoundment clearing,temporary facili-
ti es,permanent habi tat loss,and reduced prey avai l-
ability are similar to those for brown bear,treated
above.Resi dual impacts to be treated through com-
pensati on are much greater for black bear than for
brown bear for both denning and feeding habitats (see
Section 4.3.1 and 4.3.2).
Cl eari ng of vegetati on in the transmi ssi on corri dor
wi 11 also result in habitat loss.Some clearing is
necessary to facilitate construction and maintenance
and to permit rapid restoration of power in case of
line breakage.Mi ni mi zati on could be achi eved by
ali gni ng the corri dor through tundra types where
possi b1e and by desi gni ng the corri dor to 1eave as
much vegetati on as possi ble.
Additi onal habitat loss wi 11 result from the access
corri dor and interference of Watana faci li ti es wi th
upstream movements (see Section 4.3.1).Disturbance
may also make some denning habitat unsuitable.No
avoidance is possible for these impacts.Alignment
of the road away from spruce forest habitats would
E-3-513
4.4 -Mitigation Plan
mlnlmlZe habitat loss.No other minimization,recti-
fication,or reduction is possible.Compensation is
the only alternative mitigation.
(vi)Wolves
Loss of hunti ng areas wi 11 reduce carryi ng capacity
for wolves mostly through reduced prey av~labi lity.
Mitigation measures proposed for ungulate populations
wi 11 avoid,minimize,or compensate for this impact.
(vi i )Wo 1veri ne
Loss of winter foraging habitat will reduce carrying
capacity for wolverine through reduced availability
of prey.A detectable change in populations is un-
likely.Avoidance is not possible.Minimization
through consoli dati on of faci liti es,spoi 1 di sposal
in the impoundment,and si de-borrow techni ques is
possible.Some compensation may occur through an an-
ticipated increase in availability of carrion due to
hazards created by the impoundment,access roads,and
other faci li ti es.
(viii)Beavers and Muskrat
The impoundments,faci lities,and access road wi 11
remove habitat for approximately 75 beaver and 5-10
muskrat.The impact cannot be avoided except through
the no-project alternative.Partial avoidance is
possible through realignment of the access road route
and desi gn changes to reduce the area di sturbed.
Additional loss may be avoided by using only borrow
si tes D,E,I,J,and K and obt ai ni ng access road
material from small upland sites rather than from
De adman Creek.Some compensati on wi 11 occur through
improved habitat downstream from the dams.
(ix)Mink and Otter
Ri veri ne habi tat wi 11 be inundated and some stream
habitat along Deadman Creek will be lost to the ac-
cess road.Parti al avoi dance is possi ble through re-
ali gnment of the road and desi gn changes to reduce
the area disturbed.Additional loss may be avoided
by obt~ning road material from outside Deadman
Creek.Some compensation wi 11 occur through improved
habitat downstream from the dams.
E-3-514
-
-4.4 -Mitigation Plan
-
-
-
.....
(x)
(xi)
Marten
Forest habitat supporting approximately 130 marten
wi 11 be lost to the impoundments access and transmis-
si on corri dors.Se 1ecti ve c1eari ng and n arrowi ng of
the transmission corridor could reduce the impact to
marten by allowi ng free movements across the corri-
dor.Marten movements are i nhi bi ted by open areas
(see Section 4.3.4).No further avoidance,minimiza-
tion,rectification,or reduction is possible for
loss of preferred coni fer forest habitat.Further
mitigation would require compensation.
Raptors and Raven
Ravens are not limited by nest sites and are not an-
ti ci pated to requi re any speci fi c mi ti gati on mea-
s ures.
C1 eari ng and fi 11i ng of the impoundment wi 11 destroy
the fo110wi ng nesti ng 10cati ons of raptors:3 bald
eagle,2 goshawk,7 golden eagle,and 1 gyrfalcon.
An unknown number of other cli ff-and tree-nesti ng
locations for owls and small hawks wi 11 also be
destroyed.Loss of tree-nesti ng locati ons wi 11 occur
during impoundment clearing,and could be temporarily
avoided by leaving nest trees (and adjacent perch
sites for bald eagle).
The actual number of breeding pairs of golden eagles
affected wi 11 be 4 or 5,as some of the nesti ng
locations are alternate nest sites and unlikely to be
used simultaneously.Most of the suitable cliff-
nesti ng habitat upstream from the Watana dam wi 11 be
lost.Total avoidance of this impact is feasible
only through the no-project alternati ve.Destruction
of the golden eagle nesting location in Borrow ~te E
could be avoided.No minimization,rectification,or
reduction is possible for other tree-or c1iff-
nesting locations.Compensation could be provided
through the creation of cliff habitat,repositioning
of some nests,and providing artificial platforms,
nests,and/or cavities for tree-nesters.The success
of such methods and a descri pti on of the techni ques
avai 1ab 1e appear in Appendi x 3.1.
Without mitigation,salmon runs are expected to de-
crease in the reach downstream from Devi 1 Canyon as
far as Talkeetna.This may affect bald eagles in
E-3-515
4.4 -Mitigation Plan
this reach.The impact wi 11 be ~ntirely av~ded by
maintenance-level mitigation for salmon in this reach
(see Section 2.4.4[a]).
(xii)Waterbirds
The impoundment will flood riparian and river breed-
ing and/or feeding habitats for spotted sandpiper~
mew gull,harlequi n duck,common and red-breasted
merganser,semipalmated plover,wandering tattler,
arcti c tern~and di pper.Additi anal losses of nest-
ing habitat in forests will occur for goldeneye and
lesser yellowlegs.Trumpeter swans are not known to
nest in any of the affected project areas.No avoid-
ance,minimization,rectification,or reduction is
possible.Densities of all waterbird species are low
in the middle basin,and compensation on a scale
comparable to loss is not rea1i sti c.
(xii i)Terrestri a1 Bi rds
The impoundment and other project facilities will
'cause loss of habi tat for some esti mated 103,000
small terrestri a1 bi rds.No avoidance is possi ble.
Reduction of loss in the most densely populated and
high diversity habitats is possible through aligning
access and transmi ssi on corri dors away from these
habitats.Although numerical losses are large and
proportionate losses to the middle basin populations
of some species are significant,specific in-kind
compensati on for each speci es on the exact scal e of
project impact does not appear realistic.Habitat
enhancement measures for other speci es wi 11 provi de
some i n-ki nd mi ti gati on for cert ai n assemb 1ages of
small birds,although the most highly affected
communi ti es (i .e.,forest bi rds)wi 11 not be provi ded
mi ti gati on in thi sway.
(xiv)Small Mammals
The impoundment and other project faci li ti es wi 11
cause a si gni fi cant loss of habitat for some speci es
of small mammals.No avoi dance is possi ble.All
speci es are qui te common in other areas,and only
speci es rest ri cted to forested h abi tat s (i.e..red
squi rrel,porcupi ne,snowshoe hare,and pygmy shrew)
would lose a 1arge proporti on of potenti al habitat in
the basin.Reduction of loss to these species may be
accompli shed by ali gni ng the access and transmi ssi on
E-3-516
4.4 -Mi ti gati on Pl an
....
-
-
(b)
corri dors away from forest habi tat.Speci fi c i n-ki nd
compensati on for each species does not appear to be
reali sti c.Habitat enhancement measures for other
speci es wi 11 provi de some i n-ki nd compensati on for
certain assemblages of small mammals.The most
severely affected speci es,menti oned above,wi 11 not
be provided mitigation in this way.
Mortality Factors
(i)Hunti ng and Trappi ng Mortali ty
Improved access to the middle basin is anticipated to
have a negative impact on some wi ldlife populations
by i ncreasi ng mortali ty from hunti ng and trappi ng.
Protection conferred through management by the ADF&G
varies between species and areas.
Moose,caribou,and Dall sheep are considered high
profile and high priority species.Census data
collected annually by ADF&G wi 11 provide data suffi-
ci ent for management through regul ati on of harvest
for these speci es.Harvest of Da 11 sheep i s st ri n-
gently controlled,and nearly all legal rams are
currently harvested each year.The legal take for
this species is not likely to change,although,with
improved access,demand may increase.The di stri bu-
tion of harvest of moose and caribou wi 11 change with
improved access,effectively distributing the take
over 1arger porti ons of the basi n popul ati ons.The
harvest of caribou,like that of Dall sheep,is
contro 11 ed by permi t.Because of increased success
anticipated to result from improved access,the
n umber of permi t s issued may be reduced.However,
assuming that management goals for the Nelchina herd
remai n the same,the legal harvest allowed by ADF&G
is also likely to remain constant.Caribou subpopu-
1ati ons with litt le or no current harvest wi 11 face
increased mort ali ty,whi 1e current ly accessi b1e popu-
1ati ons may experi ence a decrease in hunter take.If
management goal s are altered to treat subpopul ati ons
of the herd,or to allow a change in herd size,the
legal harvest may either increase or decrease.Moose
harvest in the middle Susitna basin is not as strin-
gently regulated as Dall sheep or caribou harvest.
GMU 13 is a trophy management area for moose (only
bull moose wi th racks 36 11 across may be taken),a
strategy designed to protect the resource in an area
E-3-517
4.4 -Mitigation Plan
with poor recruitment (see Section 4.2.1 [a]).With
present regulations,improved access will increase
the harvest of moose.Carry capacity wi 11 simultan-
eously decrease because of loss of habitat resulting
from development.Harvest regulations for moose are
1;kely to be changed to rna;ntai n the remai ni ng popu-
1ati on of moose in the mi ddle basi n.ADF&G manage-
ment can avoid negative impacts to moose caused by
increased harvest resulting from improved access.
Improved access could also increase the illegal take
of all species.For moose,caribou,and Dall sheep,
which are all monitored and managed to assure future
harvest opportunities,the impact of increased poach-
ing would be transferred to the legal users through a
decrease in the legal harvest.
Large pred ators (b 1ack bear,brown bear,and wo If)
are consi dered competi tors for the harvest of ungu-
lates and are frequently given lower priority or are
subject to control to insure future harvest opportun-
ities for more desirable species.The current take
of wolves is largely illegal.Improved access wi 11
reduce populations of these species in the absence of
specific protection.For users,harvest opportunity
will increase substantially unti 1 populations are re-
duced through overharvest or provided protection.
Consi deri ng reduced moose popul ati ons and i ncreasi ng
harvest demand,reduced predator populations are
likely to be considered advantageous.Protection is
not likely unti 1 populations are reduced to a level
in accordance with harvest goals of ungulates.
Furbearers are rarely given specific protection.
Population data for furbearers are generally not
collected by ADF&G,and local areas subject to heavy
use are vulnerable to overharvest.The take of fur-
bearers and the risk of overharvest are controlled by
fur values.When fur values are high enough,access
is probably a less important factor,and even rela-
tively remote areas can become vulnerable to over-
harvesting.All furbearers are likely to become less
avai 1ab le above the d amsites bee ause of adverse popu-
lation effects of the project.Aquatic and semi-
aquati c furbearers wi 11 ;ncrease in abundance and
accessi bi 1;ty in the downstream reach between Devi 1
Canyon and Talkeetna.Some additional compensation
for upstream loss of beaver and muskrat habitat would
E-3-518
,"."
1"""\
!
!
....
-
4.4 -Mitigation Plan
be possible by enhancement of those sloughs which are
not reserved as salmon-spawning habitat (13 sloughs;
see Section 2.4.4[aJ).Adjacent prime beaver habitat
would provide an adequate source of colonizing indi-
viduals for the river sloughs even with a substantial
annual harvest,as long as those adjacent areas
(which will remain inaccessible)maintain viable
popul ati ons.
Impacts of increased hunting and poaching mortality
resulting from increased access can be avoided during
construction by prohibiting access to nonproject per-
sonnel and by restricting and/or prohibiting hunting
and trapping by project personnel.During operation,
regulation of hunting and trapping wi 11 be under the
jurisdiction of the ADF&G and beyond the control of
the Power Authority,although the Power Authority may
assi st the ADF&G ina number of ways.Some compensa-
tion for project impacts on wi ldlife populations can
be accomplished through improved management ability
conferenced by providing data obtained through moni-
toring programs to the ADF&G and by continued inter-
acti on between the agenci es in i denti fyi ng and treat-
ing project impacts on both wi ldlife and user popula-
t ions.
The powers of the Board of Game and the Commissioner
of Fi sh and Game to regul ate harvest in response to
problems that might arise from the Susitna Hydroelec-
tric Project were outlined by ADF&G (1983a).The two
main problems requiring a regulatory response were:
(1)increased harvest and (2)reducti on of harvest-
able surplus.The following actions were identified
as being frequently taken:
-Shorten or close the season;
-Schedule the season at a time when animals are less
vulnerable or hunters are less efficient;
-Reduce the bag limit;
-Re st ri ct the harvest to speci fi c sex and age
classes;
-Create a closed area;
E-3-519
4.4 -Mitigation Plan
-Create a speci al use area,e.g.,where motori zed
vehicles are prohibited for hunting,thereby making
hunters less efficient;
-Use a permit hunt where a limited number of indi-
vuals are allowed to hunt;and
-Use a registration hunt where hunters must check in
before and after hunti ng.Thi s allows careful
moni tori ng of hunter effort and harvest.When the
desi red number of animal sis harvested,the season
is closed by announcement.
ADF&G (1983a)i ndi cates that each of these acti ons
has adverse secondary effects such as increasing the
cost of management or restricting user opportunities.
The typi cal sequence of events is:moni tori ng and
identifying a problem;regulatory changes are pro-
posed to the Board of Game by either the Department
of Fi sh and Game or any i ndi vi dua 1 or group;exten-
sive opportunities for public comment are provided;
and the Board then closes regulations to protect the
problem with the least adverse impact on users.The
Board typi cally responds wi thi n a one-yer peri od
(ADF&G 1973a).If the problem is acute,the season
can be immedi ately closed by the Commi ssi oner of Fi sh
and Game.
(ii)Additional Mortality
Mortality to populati ons of some speci es is li kely to
increase significantly because of hazards associated
wi th project features.The access road wi 11 cause
accidental mortality of moose,caribou,some fur-
bearers,small mammals,and bi rds.The rai 1 access
and increased trai n traffi c on the Al aska Rai lroad
are li kely to become substanti al mortality factors
for moose.Tr ansmi ssi on li nes are a source of
electrocution mortality for large raptors and colli-
sion mortality for swans.The selected transmission
tower and li ne confi gurati on is such that 1itt le
possibility of electrocution exists.However,the
possibi lity of electrocution remains along the tem-
porary 34-kv constructi on transmi ssi on li ne to be
bui It from Cantwell to Watana vi a the Denali
Hi ghway.
E-3-520
p:;---.',
"..-
.-
....,
4.4 -Miti gati on Pl an
The significance to wildlife population levels of
mortality because of project features cannot be
predicted at the present time.Monitoring of mortal-
ity levels and modeling of their population effect
would allow a more thorough analy~s of their signif-
icance.For moose and caribou,any significant im-
pact would be transferred to users through regulation
to maintai n vi able populations.
Electrocution can be totally avoided through proper
pole/line configurations.No avoidance is possible
for other mortality sources.Mortalities caused by
collision with vehicles could be minimized through
regulation of traffic when caribou are present in
large numbers and through decrea~ng the·maximum
speed limit at all seasons.Further reductions could
be conferred through mi ni mi zi ng or prohi bi ti ng pri-
vate vehicle traffic,bussing employees to their work
sites,and/or reducing the frequency of project
vehicle traffic through a traffic-scheduling and
control program.
The dest ructi on of nui sance ani ma 1s wi 11 be a source
of mortality for bears,foxes,and wolves.The crea-
tion of nuisance animals will negatively affect the
wi ldli fe popul ati ons,the health and safety of proj-
ect personnel,and the overall cost of the project.
Bears,wi th thei r low reproducti ve potenti a 1,low
densities,and large home ranges,wi 11 be susceptible
to severe population-level impacts.The impact can
be avoided only through strict enforcement of state
regulations prohibiting feeding of wild animals;
fencing all construction camps and landfills;incin-
erati ng all putresci ble ki tchen waste dai ly;coveri ng
solid waste landfi lls with soi 1 dai ly;providing
secure garbage cont~ners in work areas and requiring
t heir use by emp 1oyees and adequate c1eani ng and
emptyi ng schedul es;assi gni ng per sonne 1 responsi -
bi lity for maintaini,ng clean work areas;and strictly
enforcing all related regulations.During construc-
tion of the trans-Alaska oil pipeline,workers were
prohibited from feeding animals and infractions were
treated through immediate firing.Infractions of
this type increase the vulnerability of all project
personnel to mauli ng and di sease,and the problem
must be dealt wi th seriously.No amount of faci li ty
m~ntenance or incorporation of specific design
E-3-521
4.4 -Mitigation Plan
features wi 11 eli mi nate thi s impact if project per-
sonne 1 are not adequately informed and cont ro 11 ed.
Additional problems commonly arise when comprehensive
garbage incineration plans are not adequately imple-
mented.The most typical shortcoming is careless
i nci nerati on.Inci nerators must be 1arge enough or
numerous enough to ensure that garbage is completely
burned and not just charred.The project construc-
tion facilities,village,and campsites should also
be fenced securely and gates moni tored to mai ntai n
the effectiveness of fencing.In addition to the
above mi ti gati on measures,a worker ori entati on pro-
gram i ncludi ng bri efi ngs on feedi ng regul ati ons and
project si te clean li ness woul d assi st in avoi di ng
this impact.An animal control strategy with trained
personnel should al so be incorporated into project
design to allow a timely and effective handling of
any wi ldlife problems which may develop during
constructi on.
(c)Di sturbance Impact s
Di sturbance is likely to reduce productivity at specific den
sites of foxes and wolves and nest sites of swans and rap-
tors.In addition,disturbance by low-flying aircraft,
particularly helicopters,may have an effect on population
productivity of ungulates.Females in late pregnancy and
young animals are particularly sensitive.These impacts can
be partly avoided through the development of guidelines
restri cti ng qround and ai r acti vity in i denti fi ed sensi ti ve
areas.Protection criteri a for Alaskan raptors are given in
Table E.3.168.
Di sturbance of bears in dens during winter months wi 11 cause
direct mortality of individuals who abandon their dens.Be-
cause locati ons of all dens in the project area may not be
known,restrictions of ground activity in identified sensi-
tive areas wi 11 only partially avoid this impact.
Di sturbance of Da 11 sheep at the Jay Creek mi nera 1 1i ck by
clearing activity before flooding,boat traffic on the
impoundment,and low-flying aircraft may cause abandonment
of the li ck whi ch could possi bly result ina decreased
carrying capacity in the Watana hills population's range.
This impact can be avoided through regulation of access and
ai r t raffi c in thi s area.
£-3-522
.-
4.4 -Mi ti gati on Pl an
4.4.2 -Mitigation Plans and Monitoring Investigations
Thi s di scussi on descri bes conti nued study progams and the mi ti ga-
tion plans incorporated into project design.A tabular summary
of the mitigation plans isprovided in Table E.13.178.Section
4.4.2(a)identifies the data req~red during and after construc-
tion to ensure appropriate types and levels of mitigation and to
identify hypothetical and unanticipated impacts.Section
4.4.2(b}describes the mitigation plans which have been incorpor-
ated into the project desi gn as a result of the impact ana1ysi s.
Section 4.4.2(c}contains a brief description of residual or
untreated impacts.
(a)Continued Monitoring and Study Needs
Many of the miti gati on p1 ans requi re current data whi ch must
be provi ded through conti nuous monitori ng of wi ldli fe di s-
tribution and/or population levels throughout the construc-
tion phase,and,in some cases,throughout the license per-
iod.Individual study needs are listed below.
(1)
(2)
(3)
Data on the frequency and location of access road and
rai lroad mortali ty wi 11 be conti nuous1y collected to
allow an analysis of population effects on moose and
caribou'.Data for moose mortality will be used in the
mode1i ng approach (Mi ti gati on P1 an 7)to assess its
importance and allow full mitigation through enhance-
ment (Mitigation Plan 6).Mortality data for caribou
wi 11 also be used to assess its importance to the
popul ati on and to assi st in scheduli ng traffi c pat-
terns (Mi ti gati on Pl an 12).
Data on changes in vegetative cover in the downstre~n
floodplain·between Devil Canyon and Cook Inlet are
requi red to i denti fy unpredi ctable changes in the
availability of early successional habitats and to
veri fy the success of mi ti gati on through habi tat
enhancement plans for moose (Mitigation Plan 6 below).
Low-level aerial photographs of the floodplain between
Devi 1 Canyon and Cook In 1et wi 11 be t aken every 10
years throughout the li cense peri od and compared with
photos from a flight to be made in 1988-1989 prior to
fi lli ng to determi ne the rel ati ve amounts of early
successi anal habitats.
Data on movements and population size of caribou are
requi red throughout the 1i cense peri od to i denti fy
unanticipated impacts and to provide information for
traff;c scheduli ng (Mi ti gati on Pl an 12).
E-3-523
4.4 -Mitigation Plan
Particular attention should be placed on assessing the
i mp act of the impoundment as a barri er,i mpedi ment,or
hazard to movement.The status of the herd wi 11 be
moni tored before,duri ng,and after the constructi on
phase to determine impacts on range use,productivity,
di sturbance,and road effects.Thi s wi 11 requi re
i nvesti gati ons throughout the 1;cense peri od.
(4)
(5)
(6)
Records of impoundment crossings and impoundment-
caused mortality duri ng the open-water peri od are
required.Impoundment surveys would identify possible
hazards to wildlife from floating debris and allow
avoidance of impacts through removal described in
Mitigation Plan 9.Records of impoundment-caused
mortality wi 11 be used to assess the impacts of such
mortality on wi ld li fe popul ati ons and the secondary
impacts to carryi ng capaci ty for cari bou.
Data on the seasonal use of the Jay Creek lick and the
distribution of use within the lick are required prior,
to i nundati on of the lower porti on of the li ck to'
assess changes in lick avai lability and value to Da11
sheep and moose.In 1983,ground observati ons of the
li ck wi 11 be conducted.The potenti al for soi 1 leach-
i ng wi 11 be addressed by collecti ng 30 soi 1 samples~
20 from various locations within the lick above and
below maximum operating level (2190 feet)and 10 from
nearby control soi ls.These samples wi 11 be analyzed
in a commercial laboratory for sodium,potassium,
calcium,and magnesium.The collections and tests
wi 11 be repeated three years after i nundat i on to
determi ne whether 1eachi n9 has occurred.Thi s wi 11
provide data to determine the appropriate level of
mitigation (Mitigation Plan 13).
Information on the locations of black and brown bear
dens and active fox and wo 1f dens is requi red to
i denti fy sensi ti ve areas in whi ch major ground and
aerial activity will be controlled (Mitigation Plan
10).Thi swill requi re i nvesti gati ons of brown bear
and black bear and spri ng aeri al surveys for acti ve
wolf and fox dens throughout the construction phase.
(7)Investigation of wolf populations is required to
identify secondary impacts on ungulate populations and
to identify hypothesized population-level impacts to
wolves.Data wi 11 be used to determi ne the need for
compensati on for project impacts.Thi s wi 11 requi re
E-3-524
1'-.
4.4 -Mitigation Plan
studi es throughout the construction phase and three
years into the operation phase of the Watana project.
(8)Detai led i nformati on on beaver di stri buti on in Deadman
Creek and in the downstream floodplain between Devil
Canyon and Ta 1keetna before and after constructi on is
.requi red to determi ne the level of downstream mi ti ga-
tion required.Such data will be collected throughout
the license period in order to assess the effects of
various flow releases downstream.
(9)The 10cati ons of acti ve raptor nests must be deter-
mi ned each spri ng duri ng the constructi on phase to
i denti fy sensi ti ve areas in whi ch aeri a1 and ground
acti vi ty wi 11 be restri cted (Mi ti gati on P1 an·10).
Surveys wi 11 continue during operation to provide data
on the need for conti nued miti gati on through nest
habitat enhancement and provision of artifica1 nest
si tes (Mi ti gati on P1 an 22).Surveys wi 11 conti nue
until 100 percent mitigation has been realized.
(l0)The 10cati ons of swan nests in development areas must
be determined each spring throughout the construction
phase to i denti fy sensi ti ve areas in whi ch major
ground and aeri a1 acti vity wi 11 be prohi bited (Mi ti ga-
tion Plan 10).
(ll)A monitoring program wi 11 be implemented and continued
throughout the license period to document the browse
producti on of 1ands enhanced for moose (Mi ti gati on
Plan 6).Research on the proposed Alphabet Hi lls burn
(scheduled for August 1983)has already begun.Field
data on browse producti on in transmi ssi on corri dors
and other disturbed habitats,enhanced lands,and the
downstream floodplain wi 11 allow the modeling approach
(described in Mitigation Plan 7 and Section 4.3.1
[a][iiiJ)to provide an evaluation of mitigation
success and indicated additional needs.
Mitigation Plans
(l)Impoundment clearing activities will not begin until
two or three years pri or to fi lli ng.Patches of
riparian vegetation will be left uncleared until just
pri or to fi lli ng.Del ayed c1eari ng wi 11 temporari 1y
avoi d impacts of habi tat loss to marten,moose,and
black bear.Avoiding clearing during the winter and
early spring months would prevent disturbance of moose
E-3-525
4.4 -Mitigation Plan
during calving and brown and black bears during hiber-
nati on.Preci se cleari ng schedules wi 11 be determi ned
in consultati on wi th resource agenci es.
(2)Habitat loss for all species will be minimized through
use of si de-borrow techni ques for road constructi on
(described in Section 3.4.2[a][i]),depositing spoil
in future impoundment areas or depleted borrow sites,
and canso li d at i on of proj ect f aci 1it i es.5i de-borrow
t echni ques wi 11 reduce the number of borrow si tes
requi red for constructi on of the access road between
the Denali Hi ghway and Watana.Ai rport,construction
sites,and camp structures will be as confined and as
close to the dams as possible.
(3)Revegetati on and ferti li zati on of di sturbed si tes
(described in Section 3.4.2[a][iJ)will minimize the
period of temporary habitat loss.In particular,it
wi 11 provi de spri ng and wi nter forage for moose for
2 to 20 years after the initiation of reclamation.
Bears are typi cally attracted to such si tes by the
high productivity and early avai labi lity of spring
forage.In some areas,this may increase the fre-
quency of bear/human encounters,wi th possi ble nega-
ti ve impacts (see Mi ti gati on Pl ans 14,15,16).
(4)Minimization of habitat loss to the transmission
corridor wi 11 be accomplished by selective clearing in
the corridor (Figure E.3.85),leaving small shrubs and
trees,and by leaving a 35-foot (10 m)wide strip of
vegetation up to 10 feet (3 m)tall.Additional
recti fi cati on for habitat loss wi 11 be provi ded by
allowing vegetation to grow to a height of 10 feet (3
m)duri ng operati on.The transmi ssi on corri dor desi gn
is described more completely in Section 3.4.2.This
desi gn wi 11 actually enhance habi tat for moose and
other wi ldli fe preferri ng vegetati on types in early
successi onal stages.Impacts of habi tat loss from
other project features wi 11 be compensated for through
increased carryi ng capaci ty for moose provi ded wi th
thi s corri dor desi gn.Many other speci es (marten,
h are)wi 11 also benefi t from t hi s corri dor desi gn
because the retention of cover in the corridor wi 11
present less of a psychological or visual barrier to
movements.
(5)Habitat alterati on whi ch wi 11 occur downstream from
the Devil Canyon dam will be reduced through the use
of multilevel intake structures that will maintain
river temperatures as close to normal as possible (see
E-3-526
4.4 -Mi ti gati on Pl an
-
,.,...
,-
I
!
.....
(6)
Section 2.4.2}.This wi 11 mlnlmlze problems of vege-
tation frosti.ng and blockage of movements by open
water in wi nter.
loss and habitat
ear wi 11
~~~~:~~~~~~~~~~::measures~replacement lands
Carrying capacity for moose and bears can be improved
on most 1ands through the use of burni ng,loggi ng,
vegetation crushIng,or land clearing.These methods
allow development of early successional vegetation
whi ch has hi gher browse producti on (and therefore
carryi ng capaci ty)than the exi sti ng 1ate-successi onal
vegetati on types.Each of these methods has certain
advantag,es and disadvantages.Controlled burning is
usually the most economi cal and results in 'hi g;her
browse producti on than the other methods because
nutrient$are immediately released to the soil,and
soi 1s are warmed by greater i nso 1at;on (Vi ereck and
Schandelmeir 1980).Burning,a.1so produces higher
berry production than other methods fFdedman 1981}.
However,controlled burning is often impractical
because of land ownership and'logistic problems.
Logging can also increase browse production,particu-
1 arly when the soi 1 is scari fi ed in summer (Zasada et
al.1981).Logging is not feasible in some areas
because of topography or access and is usually more
cost ly than burni ng.Vegetati on crushi ng has been
used on the Kenai Peninsula to jmprove moose habitat
(Rege1in 1982).Access and topography also limit the
use of crushi ng to cert ai n areas.
For purposes of pro,vi;ding an esti mate of the number of
acres of land required for mitigating this impact and
the cost of these measures,the following mitigation
scenario is presented:
- A controlled burn wi 11 be conducted on state 1ands
north of the Susi tna Ri ver on the east si de of
Watana Creek.A total of 6400 acres of woodland
coni fer forest in several separate stands wi 11 be
burned to improve both browse and berry producti on.
The browse production in woodland conifer stands is
approximately 10 kg/ha (Table E.3.92).Low shrub
stands,whi ch would result from the burni ng effort
(Figure E.3.1l7),provide appro,ximately 30 kg/ha.
Burni ng of 6400 acres would thus provi de compensa-
E-3-527
4.4 -Mi ti gati on Pl an
tion for 12,800 acres of lost habitat.Si nce browse
production begins to decrease after about 12-14
years (see Figure E.3.117),the same or nearby areas
wi 11 be burned agai n after 15 years.The feasi bi 1-
i ty of thi s approach wi 11 be veri fi ed by long-term
research on the Al phabet Hi lls burn,whi ch began in
1982.The Power Authority has already provided
support for pre-burn moose and vegetation studies of
the proposed Al phabet Hi 11 s burn area.Burni ng is
scheduled for August 1983.
-The Susi tna watershed in the reach between Watana
and Devi 1 Canyon currently supports low numbers of
moose.This area was considered for habitat en-
h ancement measures.However,the area is 1arge ly
tundra,tall shrub (alder),and mixed forest.Based
on current data,it is unli kely that browse produc-
tion in tundra or tall shrub stands could be sig-
nificantly improved,and mixed forest stands already
support high browse production (Table E.3.92).This
area is therefore excluded from consi derati on for
habitat enhancement.
-Si tes exi st near the Susi tna Ri ver floodpl ai n down-
stream from Gold Creek which were cleared for agri-
culture but left unplanted.Early successional
vegetation has developed in these areas and they are
used by 1arge numbers of moose in wi nter.The
browse producti on of these di sturbed areas has not
been measured,but during moose surveys in November-
December 1982,more than 50 moose were often seen in
di sturbed fi e 1ds of 1ess than 640 acres.Browse
production in these dense stands of wi llows probably
begi ns to decli ne rapi dly after 20 years.The
avai 1abi lity of browse and the durati on of hi gh
browse production in these areas wi 11 be determined
in 1983.For a preliminary estimate of the area
required to compensate for loss of moose browse,it
will be assumed that areas currently classed as
conifer forest have only one third the browse
production of cleared areas.The Power Authority
will improve moose habitat by clearing 16,000 acres
of state 1and wi thi n 10 mi 1es of the Susi tna Ri ver
in sc attered patches.These areas wi 11 be cleared
to mineral soil by stock~ling the cleared vegeta-
t i on i n wi ndrows.As sumi ng t ht browse prod uct i on i s
improved three-fold for 16 years and that these
areas are cleared three times during the license
peri od,these 16,000 acres wi 11 compensate for the
loss of 32,000 acres of moose habi tat to the i m-
E-3-528
-
4.4 -Miti gati on Pl an
impoundment areas.The exact locati on and number of
acres to be improved wi 11 be determi ned usi ng data
from downstream vegetation studi es and usi ng the
habitat-based modeling approach described below
(Mi ti gati on Pl an 7).If browse producti on is
greater than the 3-fold increase hypothesized above,
less area will be required.A 3-fold increase in
browse producti on i s a very conservati ve esti mate,
and a 5-to 10-fold increase may be possi ble in
some vegetation types.
Burni ng of 6400 acres in the Wat ana Creek area and
clearing of an additional 16,000 acres near the down-
stream floodplain wi 11 mitigate for the loss of 42,135
acres to the impoundments,temporary and permanent
structures.Clearing and maintenance of the transmis-
sion corridor wi 11 provide additional mitigation where
the corridor traverses vegetation types which would be
enhanced by periodic clearing (i .e.,conifer forests).
It is possi ble that regulated flows may result ina
net increase in moose habitat along the downstream
floodpl ai n duri ng the li cense peri od through an i n-
crease in early successi onal ri pari an vegetati on.In
this case,no additional mitigation would be required
for downstream impacts.A monitoring program wi 11 be
imp 1emented and conti nued throughout the li cense
period to document the browse production of the lands
enhanced for moose (see monitoring Plan 11).This
moni tori ng program wi 11 provi de input into the
habi tat-based approach bei ng developed by the Power
Authority,and wi 11 result in an increase or decrease
in the number of acres managed as moose habitat,
depending on the level of mitigation achieved.Esti-
mated costs for the proposed browse enhancement mea-
sures are summari zed in Table E.3.169 Thi s flexi ble
approach to mitigation is designed to provide total
mitigation for habitat loss to moose.
The controlled burns described above wi 11 also enhance
habit at for bears.However,it wi 11 not fully compen-
sate for loss of early spring foods for bears,partic-
u1ar ly not i n years of berry crop f ai 1ure..It wi 11
increase the availability of fall foods for fatten-
i ng.
Addi ti onal enchancement and parti al compensati on for
loss of spri ng habi tat for brown bears wi 11 occur in
revegetated areas and disturbed areas.The increased
productivity in these areas,particularly in revege-
tated areas,is attracti ve to bears in early spri ng
E-3-529
4.4 -Mitigation Plan
and at all seasons because greater insolation creates
earli er green-up and increased avai labi lity of some
preferred plants.
(7)As a compensati on measure to mi ti gate for impacts to
moose,the Power Authori ty is developi ng a habitat-
based model in conjunction with the ADF&G,the USFWS,
the University of Alaska,and private consultants.
This approach wi 11 use a variety of data to determine
the impact of habitat loss on present and future moose
popu1 ati ons.Data requi rements are present ly more
completely in Section 4.3.1(a)(iii).
An estimate of the number of acres required to miti-
gate for habitat losses for moose wi 11 be determi ned
using this habitat-based approach and information from
conti nui ng studi es by the Power Authori ty.Pre1i mi-
nary estimates of the level of mitigation required are
given in Mitigation Plan 6 above based on the prelimi-
nary browse producti on fi gures presented in Secti on
4.2.1(a)(see also Appendix 3.H).
The model will also incorporate population data and
wi 11 be used to assess the significance of cumulative
impacts of habitat loss,mortali ty factors,habitat
alteration,and disturbance.The refinement and use
of,thi s mode 1 wi 11 allow 100 percent compensati on for
impacts to moose.Development of the modeling ap-
proach should also be considered out-of-kind mitiga-
tion for species impacts which cannot be otherwise
addressed.
(8)The Power Authori ty wi 11 assi st the Al aska Board of
Game in conducting a controlled moose hunt within the
project area to avoi d over-browsi ng of the area by
di sp 1aced moose.Th e need for such a hunt wi 11 be
assessed usi ng the modeli ng approach descri bed above.
Available energy and protein will be measured to
determi ne carry;ng capaci ty of adjacent range in 1983
and 1984.A census of the impoundment and adj acent
areas will be conducted just prior to clearing to
assess the status of the moose population relative to
carryi ng capaci ty.A hunt would be conducted if
studi es determi ne that the recei vi ng areas cannot
support displaced moose without degradation of carry-
i ng capaci ty.
(9)Hazards to movement created by the impoundment wi 11 be
reduced through clearing of the impoundment zone prior
to floodi ng and through a program of debri s removal as
E-3-530
.-
.....
.....
4.4 -Miti gati on Pl an
necessary to conti nue throughout the li cense peri od.
Monitori I1g of the impoundment duri ng the open water
peri od wi 11 i denti fy debri s hazards.
(10)Sensitive wildlife areas identified in the monitoring
studies will be protected from disturbance from
project aircraft by the following guidelines and
measures:
Pi lots w-i 11 be requi red to mai ntai n a 111i ni mum
a lti tude of 1000 feet above ground 1eve 1 except
duri ng take-off and 1 andi ng throughout the basi n.
-Ai rcraft 1andi ngs wi 11 be prohi bited withi n 1/2 mi 1e
of the Jay Creek mineral lick between Apri 1 15 and
June 15.
-Ai rcraft 1andi I1gs wi 11 be prohi bi ted wi thi n the
Nelchina caribou herd calving area in the Talkeetna
Mountai ns (see Fi gure E.3.93)between May 15 and
June 30.
-Ai rcraft 1andi ngs wi 11 be prohi bi ted wi thi n 1/4 mi le
of known active wolf dens or rendezvous sites during
May 1 through July 31.
-Ai rcraft 1andi ngs wi 11 be prohi bi ted wi thi n 1/2 mi 1e
of acti ve golden eagle nests between March 15 and
August 31 each year (Table E.3.168).
-Ai rcraft 1andi ngs wi 11 be prohi bi ted wi thi n 1/4 mi 1e
of active bald eagle nests between March 15 and
August 31 (Table E.3.168).
Ai rcraft 1andi ngs wi 11 be prohi bited wit hi n 1/4 mi le
of acti ve gyrfalcon nests between February 15 and
August 15 (Table E.3.168).
-An aircraft buffer zone of at least 0.25 mi le or
1000 vertical feet will be established around lakes
used by trumpeter swans during the nesting season.
-All ai rcraft restri cti ons and schedul es wi 11 be
provi ded to ai rcraft pi lot sin a conci se manual.
Ground di sturbance of i denti fi ed sensi ti ve areas wi 11
be avoi ded through the gui de li nes and measures de-
scri bed below.For the purposes of thi s di scussi on,
mi nor ground acti vity inc 1udes short-term reconn ai s-
sance and exploration type programs such as field
E-3-531
4.4 -Mitigation Plan
inventories.Major ground activity involves large
numbers of personnel;equipment;surface disturbance;
noi se;or vehi cul ar acti vi ty;such as c leari ng,pad
construction,blasting,and faci lity construction.
Protecti on cri teri a for nesti ng raptors whi ch are
currently accepted as guidelines by the ADF&G,and the
USFWS were developed for the proposed Al aska Natural
Gas Transportati on System (Behlke 1980)by raptor
bi ologi sts in the state.These general cri teri a were
modified for application to the Susitna Basin based on
known phenology of nests and are presented in Table
E.3.168.Although there may be a very small amount of
nesting activity before or after these dates,the vast
majority of nesting attempts wi 11 be covered under the
proposed cri teri a.In general,the early nest peri od
is more sensitive and the criteri a are more conserva-
tive in the early season,reflecting this difference.
-Known raptor nesti ng locati ons wi 11 be assumed to be
occupi ed unti 1 June 1 of each year,after whi ch,
protecti on measures wi 11 be wi thdrawn for the re-
mainder of the year if the nest is documented to be
i nacti ve.
-Major ground acti vHy wi 11 be pro hi bHed wHhi n 1/2
mi le of the Jay Creek mineral lick between Apri 1 15
and June 15.The reservoi r adjacent to the li ck
will be closed to boat and floatplane use within 1/2
mi 1e of the lick.
Cl eari ng acti vi ti es in the impoundment area wi 11 be
restricted to nonsen~tive periods near areas i~en
tified as sensitive to disturbance (e.g.,concentra-
tions of calving moose,brown and black bears,
denning wolves,migrating caribou,raptor nests,
et c.) .
-Major ground acti vi ty wi 11 be pro hi bi ted wi thi n 1/4
mi 1e of all known acti ve bear dens between Sep-
tember 15 and May 15.
-Major ground acti vi ty wi 11 be prohi bi ted wi thi n 1/2
mi le of waterbodies used by swans during the nesting
season and other times when swans are present.
-Ground acti vity wi 11 be prohi bited wit hi n 1/4 mi le
of known acti ve wo 1f den s or rendezvous sites be-
tween May 1 and July 31.
E-3-532
....
-
.....
4.4 -Mi ti gati on Pl an
-Major ground acti vity wi 11 be prohi bi ted wi thi n 1/2
mi 1e of active golden eagles nests between March 15
and August 31,within 1/4 mile of active bald eagle
nests between March 15 and August 31,or within 1/4
mi 1e of gyrfalcon nests between February 15 and
August 15 (Table E.3.168).
In aqdition to these general guidelines,two specific
nests are anti ci pated to be vulnerable to di sturbance.
These are treated below.
The Watana-Devi 1 Canyon porti on of the access road
between Mi le 32.5 and Mi 1e 35 cannot be reali gned away
from golden eagle nesting location GE-18 because of
topographic and engineering considerations.To mini-
mize disturbance from construction activities,con-
struction within 0.5 mile of the nesting location will
be limited to the nonsensitive period (August 31-
March 14)if the nest is active (see Table E.3.168).
Di sturbance after road constructi on wi 11 be kept to a
minimum by ensuring that no activities occur south of
the road or along the cli ff-top for a di stance of 0.5
mi le east and west during the sen~tive period.
It is not feasi b1e to reali gn the rai 1road access
route farther away than 0.25 mi le from bald eagle
nesti ng locati on BE-8 between Mi le 2 and Mi 1e 3 be-
cause of topograph.i c ··and engi neeri ng consi derati ons.
If the nesting loc·ation is active,efforts will be
made to limit construction to the nonsen~tive period
(August 31-March 14)to minimize disturbance.
(11)Although complete avoidance of the impacts of altered
c ari bou movement sand range use i s not possi b1e with
the route chosen,desi gn changes in the access road
and realignment to minimize effects on current major
use areas of the Nelchina range will minimize or
reduce its impact.Although this alignment avoids
some areas for cari bou calvi ng,some cows that calve
in the mountai ns to the west of the road would sti 11
be affected.Changes in road alignment are described
in greater detail in Section 3.4.2[a][i]).Use of
side-borrow techniques wi 11 minimize ~hysical and
visual barrier effects of the road to caribou and
other speci es.Thi s techni que results ina fi ni shed
road profi 1e less than 4 feet above ori gi na1 ground
level (see Figure E.3.83)and minimizes amount of
habitat lost to materi al sites .
E-3-533
4.4 -Mi ti gati on P1 an
(12)The effects of vehicle traffic on caribou movements (a
more seri ous impact than the actual presence of the
road)can be minimized by reducing the volume,speed,
or frequency of traffi c on the road.Pub1i c access
will be prohibited during the construction period.
The Power Authority is currently revie~ng options for
reducing traffic volume.Further minimization of
impacts could be provi ded through bussi ng workers to
the site,allowing only convoy traffic,or reducing
the speed limit and volume of traffic during sensitive
periods.Because dust clouds behind vehicles add to
the vi sua1 effect on cari bou,water trucks wi 11 be
used to control dust along the road duri ng the con-
struction phase.Continued monitoring (Monitoring
Plan 3)will evaluate the residual impact (if any)on
c ari bou and the need for out-of-ki nd mi ti gati on for
c ari bou.
(13)If monitoring of Dall sheep (described in Section
4.4.2 [i])indicates a population-level effect of
parti al i nundati on of the Jay Creek mi neral 1i ck,new
soi 1 wi 11 be exposed to recti fy the impact.Moni tor-
ing use and comparison of soil samples (Continued
Study 5)will allow evaluation of the effectiveness of
thi s miti gati on.
(14)The impact of overharvest of game speci es wi th i m-
proved access wi 11 be avoided during construction by
prohi bi ti ng pub 1i c access vi a the project road or ai r
fi e1d,pro hi bi ti ng employees and thei r fami 1i es from
usi ng project faci 1i ti es or equi pment for hunti ng and
trapping,and by providing data from monitoring in-
vestigations (described in Section 4.4.2[iJ)which may
assist the Alaska Board of Game in regulating hunting
and trapping activities in the area.During the
operati on phase,the Power Authori ty wi 11 have no
control over harvest acti vi ti es but wi 11 conti nue to
provi de any perti nent dat a to the ADF&G and assi st ance
in their management activities.
Studies will provide information on the bear popu1a-
ti on and the di stri buti on of bear harvest whi ch wi 11
i ndi cate the need to recommend restri cti ons on bear
hunts to the ADF&G to protect brown and black bears.
Concentrati ons of bears may occur in some proj ect
areas which wi 11 also receive regular human access and
presence.Regul ati ons on ei ther the season or the
location of the hunt could be used to protect bear
populations from overharvest.
E-3-534
4.4 -Mi ti gati on Pl an
....
-
....
-
.....
(15)
The Power Authority wi 11 recommended hunting and
trapping restrictions to protect wolves within the
project are,a and allow the formati on of new home
ranges and hunti ng patterns.Thi s woul d mi ni mi ze the
secondary impact of soci al stri feand upheaval caused
by the alterati on of hi stori cal pack boundari es.
Further restrictions may be recommended for other
furbearers if dat a from ongoi ng i nvesti gati ons
indicate a need for protection.
The creati on of nui sance ani ma 1s wi 11 be avoi ded
through combined implementation of the following
garbage-contro 1 and educati on measures:
An Envi ronmental Bri efi ng Program for employees wi 11
be required (descri bed in Appendi x 3.B)and wi 11
include briefings on regulations prohibiting feeding
of animals and reasons for the restrictions.
-St ate regul ati ons prohi bi ti ng feedi ng of wi ld
animals will be strictly enforced.
-Constructi on c amps and 1 andfi 11 s wi 11 be fenced wi th
bear-resi stant fenci ng and gates wi 11 be moni tored
to ensure the effectiveness of the fencing.
-Secure garbage containers wi 11 be required in work
areas.
-Personnel wi 11 be assi gned the responsi bi li ty for
picking up and disposing of all discarded refuse in
work areas and along roads .
-Putrescible kitchen wastes wi 11 be stored indoors
and completely incinerated dai ly or more often,if
requi red,inadequate i nci nerators.
-So li d waste 1andfi 11 swill be covered wi th soi 1
dai ly,or as required by permit stipulations.
Wi ldlife problems may persist to a small degree even
wi th such precauti ons.Increased use of bear concen-
tration areas by humans (e.g.,Prairie Creek)and
attraction of bears to some sites (e.g.,revegetated
areas)wi 11 both i ncreasebear/human confli cts.The
constructi on manager,wi 11 be instructed to develop an
animal control strategy directed at avoiding and
minimizing all project-related problems and to respond
prompt ly to any si tuati ons that ari se.
E-3-535
4.4 -Mi ti gati on Pl an
(16)Decreased avai 1abi li ty of salmon to bears wi 11 be com-
pletely compensated for by enhancement of 13 sloughs
between Devi 1 Canyon and the conf1 uence of the Chul-
itna and Talkeetna rivers (see Section 2.4.4[aJ).
Increased activity at Prairie Creek would be a second-
ary impact of the project that would have a negati ve
effect on brown and black bears whi ch make season a1
movements to the area during salmon runs.The Power
Authori ty wi 11 assi st resource management agenci es in
assessing this impact and in preparing recommendations
for mitigating actions.Without protection,the
stream is likely to be developed for mining or for
recreati onal si tes.The occurrence of bear/human
encounters is likely to increase in Prairie Creek,no
doubt to the detriment of both parti es.Deli berate
recreational development would also be severely detri-
mental to the basin populations of bears who make
regular movements to Prairie Creek.
The impacts of decreased av~labi 1ity of ungulate prey
for brown bear,black bear,and wolf wi 11 be reduced
through measures to avoid,minimize,or compensate for
impacts to ungulate populations.However,it is
1i ke1y that predator popu1 ati ons wi 11 be reduced
through harvest as a management strategy to allow
increased harvest of ungu1 ates by humans.Therefore,
complete mitigation of impacts is not planned for
these speci es.
Additional compensation for bears for reduction in
both spri ng forage and prey avai 1abi 1ity wi 11 be pro-
vi ded through revegetati on of di sturbed si tes (see
Section 3.4.2[aJ[iJ).Bears are adaptable and may be
able to replace some prey in their diet through in-
creased consumption of vegetation.The occurrence of
di sturbed and,in parti cu1 ar,revegetated si tes wi 11
provi de addi ti ona1 attracti ve forage for bears.In
areas of frequent human use,revegetated sites wi 11
have a potenti a1 negative impact (see Mitigation Plans
3,14,and 15).
(17)Loss of habitat for aquatic furbearers wi 11 be mini-
mi zed by reduci ng gravel requi rements through si de-
borrow techni ques and uti 1i zi ng only Borrow Si tes D,
E,I,J,and K.In addition,material for the access
road in the Deadman Creek area wi 11 be obt ai ned if
necessary from small upland sites outside the Deadman
Creek drai nage (Fi gure E.3.37).Further miti gati on
wi 11 be provi ded in the downstream f1 oodp 1ai n as de-
scri bed in Mi ti gat;on P1 ans 18 and 19 below.
E-3-536
-
4.4 -Mi ti gati on P1 an
(18)Mitigation for loss of habitat and a quantitative
assessment of potenti a1 beaver habitat wi 11 be pro-
vided by the development and testing of a model of
beaver carryi ng c apaci ty for the Devi 1 Canyon to
Talkeetna portion of the floodplain.Inputs to the
model wi 11 include data on hydrology,slough mor-
phology,and forage availability;and the results of
different flow releases and water temperatures on
avai 1abi 1ity of overwi nteri ng habitat wi 11 be tested.
Conti nued moni tori ng of beaver popu1 at ions wi 11 test
the va1i di ty of the model and refi ne its accuracy.
The development of thi s model wi 11 a1 so miti gate for
residual impacts on furbearers..
-
(19)
(20)
Loss of habitat for aquatic and semi aquatic furbearers
(especi ally beaver)wi 11 be compensated for through
enhancement of sloughs in the reach between Devi 1
Canyon and the ,conf1 uence wi th the Chu1 i tna and
Talkeetna ri verso Thi rteen sloughs in thi s reach wi 11
be managed as salmon spawni ng sloughs,and beaver are
1i ke1y to be acti ve1y excluded from these.Of the
remaining sloughs,the beaver model will indicate
enhancement measures req~red for colonization and
overwinteri ng by beavers.Slough enhancement measures
wi 11 a.1 so benefit muskrat,mi nk,and otter and may
provi de comp 1ete compensati on for aquatic and semi-
aquatic furbearers.
The loss of raptor tree-nesti ng 10cati ons wi 11 be
temporari 1y minimized by delaying impoundment clearing
operations unti 1 the two or three years prior to fi 11-
ing and,thereafter,by leaving islands of vegetation
around known nesting locations.Clearing activities
wi 11 be schedu1 ed to avoi d the early nesti ng season.
Active nests wi 11 thereafter be protected by disturb-
ance gui deli nes out 1i ned in Mi ti gati on P1 an 10.
Destructi on of the bald eagle nest in Deadman Creek
(BE-8)wi 11 be avoi ded throughrea1i gnment of the
access road northwestward and westward to pass 0.5
mile from the nest tree.This distance will also
minimize disturbance to the nesting p~r.
Destruction of the currently inactive golden eagle
nest (GE-ll)located within Borrow Site E will be
avoi ded by not mi ni ng that area of the site.Di sturb-
ance of the nest,if it becomes acti ve,wi 11 be avoi d-
ed by prohibiting mining of the site during the nest-
ing period,March 15 through August 31.
E-3-537
4.4 -Mi ti gat ion Plan
(21)The unavoidable loss of raptor nesting locations wi 11
be fully compensated for by si te enhancement and the
creation of artificial nesting locations.The tech-
ni que is descri bed wi th examples in Appendi x 3.1.The
f 011 owi ng speci fi c measures wi 11 be taken.
- A combination of several of the enhancement measures
descri bed in Appendi x 3.I wi 11 be used to provi de
artificial nesting locations for bald eagles until
at least four successful new eagle nests have been
established in the middle or upper basin.Bald
eagles have shown little reluctance to use nests
that have been reconstructed after havi ng been blown
down (Olendorff et al.1980).The nests that are to
be inundated wi 11 be reconstructed in adjacent
areas.
-Natural-appearing nests will be placed in appro-
priate trees (especially large balsam poplar)in
suitable habitat downstream from the damsite or
along tributaries such as Portage Creek (presently
unused by bald eag 1es).Addi ti ona lly ~the c anopi es
of other trees wi 11 be modified by removing tops or
some upper li mbs to make them more attracti ve as
nesting locations for bald eagles.
The success
insure that
i ngs occur.
approach is
of these measures will be monitored to
at least 4 successful bald eagle nest-
The estimated cost of this mitigation
summarized in Table E.3.171.
-Ten nesting platforms for golden eagles containing
artificial stick nests wi 11 be placed on the tops of
transmission towers as construction occurs (see
Figure E.3.117).Costs estimates are provided in
Table E.3.172.
-Nesti ng habi tat for goshawks wi 11 be improved both
by provi di ng arti fi ci al nests and by i ncreasi ng the
edge effect in large forest stands (D.Weir 1982
Personal Communication and D.Roseneau~unpublished
data).Great horned and great gray owls commonly
use abandoned goshawk nests in Alaska (Roseneau and
Bente 1981)~and wi ll~therefore~also benefit from
these measures.Twenty nest boxes for c avi ty-
nesting kestre1s~boreal owls,and hawk owls will
also be provided and monit'ored.Cavities will be
created in the tops of several mature bi rch or
spruce trees in an addi ti onal attempt to attract
E-3-538
.....
.....
-
-
.-
-
....
.....
4.4 -Mitigation Plan
hawk owls and other cavity-nesting birds.Estimated
costs of these mitigation measures are summarized in
Table E.3.173.
Nests that can be physically repositioned higher on
the cliff (at least 50 feet above maximum pool
level)and cliffs suitable for enhancement measures
wi 11 be i denti fi ed in 1983.Some otherwi se suitable
c li ffs have no 1edges for nest bui ldi ng.Ne sti ng
1edges and perches c an be created wi th exp 1osi ves
and/or hand tools.Artificial stick nests (see
below)can also be provided on such sites.Cliff
enhancement measures wi 11 begi n in 1984.Nesting
1edges wi 11 be created on exposed c li ffs usi ng
small,shaped explosive charges and/or hand tools.
It may also be possible to attach metal and masonry
nest ledges to some cli ffs.The feasi bi lity of
physically moving original nests to new points
hi gher on the c li ff wi 11 be demonstrated and per-
fected usi ng an i nacti ve nest.Areas where bedrock
c li ffs c an be exposed by b 1asti ng and di ggi ng away
overburden wi 11 also be identified for possible
future enhancement.
The success of these measures wi 11 be determi ned
through annual monitoring efforts.A combination of
measures inc 1udi ng subsequent modi fi c ati ons wi 11 be
used unti 1 the number of successful new nesti ngs
equals or exceeds the number of nesti ng golden eagle
p~rs lost to the project.
(22)Electrocution of raptors by the temporary 34 kV trans-
mis~on line from Cantwell to the Watana site wi 11 be
avoided by emplo~ng pole/line configurations and
other safeguards proven effecti ve in other part s of
North America (Olendorff et al.1981).Special atten-
ti on wi 11 be gi ven to wi re-g appi ng and ground wi re
placement (~gure E.3.11B),armless configurations
(~gure E.3.119),and transformer installation (Figure
E.3.120).Perch guards (Figure E.3.121)and elevated
perches (Figure E.3.122)wi 11 be used if necessary to
further avoi del ectrocuti ons.These measures wi 11
totally avoid thi s impact.
(23)Loss of forest habitat for black bear,marten,small
birds,and small mammals will be minimized through the
alignment of the access road and transmission corridor
to avoid most forest areas;through usi ng the narrow-
est corri dor allowable;through mi ni mi zi ng the area
E-3-539
4.4 -Miti gati on Pl an
used for borrow extracti on by si de-borrow techni ques
for road constructi on;and through conso li dati on of
faci lities.loss wi 11 be temporari ly avoided by
delaying reservoir clearing operations unti 1 two or
three years prior to filling.Habitat loss in the
transmission corridor will be minimized by selective
clearing and minimization of the width of cleared
areas.Inhibition of marten and small mammal move-
ments across the corridor will also be minimized by
leaving a strip of vegetation along the centerline.
The ali gnment of the access corrdor has al so been
altered to avoid four red fox denning areas.
(c)Residual Impacts
(i)Moose
The measures descri bed above wi 11 pro vi de comp 1ete
miti gati on for habitat loss to moose through en-
hancement of adjacent areas and acquired replacement
lands.The carrying capacity of the middle basin
wi 11 be reduced and populations there may decrease.
The development of a carryi ng capacity model wi 11
allow an estimate of both carrying capacity and
current population level impacts.It will also
allow evaluation of the enhancement techniques and
determi nati on of acreage requi red for enhancement.
The opportunity exists to further enhance moose
h abi tat downstream from Talkeetna as out-of-ki nd
mitigation for residual impacts to other species
(see discussion of residual impacts on bears,
wolves,marten).
The model will also incorporate population data and
will allow an assessment of the population-level
effects of accidental mortality factors and harvest.
With this additional information,complete mitiga-
tion wi 11 also be provided for these impacts.
(ii)Car"ibou
The impacts of mortality factors and disturbance can
be minimized as described above,and no population-
level effects are anticipated.The likelihood of a
reducti on in carryi ng capacity resulti ng from block-
age of movements by the impoundment is unknown.
Continued monitoring of the Nelchina herd wi 11 allow
evaluation of realized impacts.If unanticipated
E-3-540
4.4 -Mitigation Plans-
impacts are demonstrated,mHigation wi 11 be pro-
vided.No in-kind mitigation would be possible for
P"I a demonstrated decrease in carryi ng capacity of the
Ne1china range.The Power Authority is evaluating
opti ons for out-of-ki nd mi ti gati on in the eventua1-
i ty that resi dual impacts are demonstrated.
(iii)Da11 Sheep
The impacts of di sturbance at the Jay Creek mi nera1
lick wi 11 be fully avoided for through restrictions
on activity in the area.The need for further miti-
gati on wi 11 be determi ned by conti nued study of 1i ck
use and soi 1 composi ti on.Demonstrated popu1 ati on-
level impacts will be mitigated for by exposure of
new soi 1 in the area ..
,...,
,....
(i v)Brown Bears
The most significant potential impact of the Susitna
hydro development project on brown bears,the crea-
tion and destruction of nuisance animals,can be
prevented by the measures out 1i ned above.Di sturb-
ance impacts are also easily avoided or minimized.
Slough enhancement for salmon and cooperati ve man-
agement of 1ands adjacent to Prai ri e Creek could
fully miti gate for loss of these food resources.
The loss of habitat has been minimized as much as
feasi b1e.No analysi s of the value of habi tat lost
is possible.Adequate methods for evaluating brown
bear habitat are not avai lable.Brown bears are a
low densi ty speci es adapted to opportuni sti c uti li-
zation of a large number of avai lab1e food resources
in a very large home range.The impact of loss of
spring feeding areas cannot be assessed,and a popu-
lation-level effect ascribable to this impact would
be di ffi cult to demonstrate.Although enhancement
measures for moose habitat wi 11 not fully miti gate
for loss of spri ng forage for brown bears,burni ng
wi 11 increase abundance of berries,a major fall and
spri ng food of brown bears.Management and mi ti ga-
tion plan conflicts militate against any in-kind
mitigation through replacement lands for brown bear.
Any reducti on in the bear popul ati on is 1i ke1y to
improve recruitment to moose and caribou populations
and wi 11 consti tute out-of-kind mi ti gati on for these
sped es.
E-3-541
4.4 -Mi ti gati on P1 ans
(v)Black Bears
The above di scussi on of brown bear is also appli c-
able to black bear,except that black bear are
generally restri cted to forested habi tat,a si gni fi-
cant porti on of whi ch wi 11 be destroyed by the
Susitna hydro project.Residual impacts will,
therefore,be much 1arger,and a si gni fi cant de-
crease in black bear numbers and di stri buti on is
anticipated.Increased recruitment in ungulate
populations resulting from decreased bear densities
wi 11 consti tute out-of-ki nd mi ti gati on for black
bear.
(vi)Wolves
Di sturbance of wolves at dens wi 11 be avoi ded as
descri bed above.Decreased avai 1abi 1ity of prey
wi 11 be mi ni mi zed through the miti gati on measures
proposed for ungulates.The Watana pack is likely
to be eliminated and the remaining packs'composi-
tion and ranges are likely to shift and fluctuate
unti 1 a new equ;1i bri um is reached.Harvest manage-
ment goals for ungulates and mitigation plan con-
f1i cts mi 1i tate agai nst AOF&G management of rep1 ace-
ment lands for wolves.Considering the increasing
demand for harvest of ungulates and the possible
decreased opportuni ty for harvest of moose in the
middle basin,reduced wolf populations are likely to
be consi dered advant ageous and wi 11 consti tute
out-of-kind mitigation for moose and caribou.
(vi i)Wolveri ne
Wolverine are wide-ranging and occur in low densi-
ties.Therefore,loss of habitat and increased
harvest are unlikely to cause a detectable decrease
in wo 1veri ne abundance.The anti ci pated increase in
availability of carrion caused by higher turnover
rates in moose popu1 ati ons wi 11 mi ti gate for a
decrease in food resources resulti ng from habi tat
loss.Further miti gati on is not anti ci pated to be
necessary.
(vi i i)Aquati c and Semi aquati c Furbearers
Habi tat loss upstream from the damsi tes wi 11 be
compensated for through habi tat enhancement between
'[-3-542 ('CC'--
I'"""
"'""
-
-
-
4.4 -Mi ti gati on Pl ans
Devi 1 Canyon and Talkeetna.loss of stream habitat
in Deadman Creek will be minimized.The modeling
effort to be developed for beaver wi 11 allow deter-
mination of flows and slough enhancement required
for complete compensation for that species.Quanti-
fication of impacts and the extent to which mitiga-
tion is provided for muskrat,mink,and otter cannot
be determined from currently available data.
No compensation for increased harvest is possible
beyond the provi si on of enhanced downstream habi tat.
If fur values are high,sustained high levels of
harvest may decrease populations.Adjacent prime
habitat,on which access wi 11 not be improved,wi 11
continue to be a source of colonizing individuals as
long as those populations remain viable.
,(i x)Terrestri al Furbearers
Di sturbance of red fox dens wi 11 be avoi ded.Loss
of forest habit at for a 11 speci es wi 11 be mi ni mi zed.
Precise quantification of residual impacts is not
possible for any terrestrial furbearer.However,
only marten are expected to suffer substantial popu-
lation reductions and decrease in carrying capacity.
Residual impacts for marten are large.Enhancement
method s for moose wi 11 further increase loss of
habitat for marten.Opportunities for mitigation
for loss of forest habitat are limited both by
management priorities for economically more valuable
speci es and confli ct with miti gati on plans for
moose.
-
--
(x)Raptors and Ravens
Ravens are not 1i mi ted by nest si tes and are not
anti ci pated to decrease in abundance "j n the mi ddle
basin.Mitigation will completely compensate for
loss of nesti ng habi t at and nesti ng 1ocati ons for
bald and golden eagles,and gyrfalcons.A preci se
assessment of impacts to other tree-nesting raptors
which will be negatively affected is not possible.
The increase in edge habi tat near project faci li-
ties,the transmission corridor,and revegetated
si tes wi 11 enhance habi tat for acci pi ters (goshawks
and sharp-shi nned hawk),thereby compensati ng for
loss of the limited available habitat in the im-
poundment area.Ground-nesting species are not
expected to suffer loss of nest habitat.
E-3-543
4.4 -Mitigation Plans
(xi)Waterbi rds
No in-kind mitigation is possible for loss of flu-
vi ati le and ri ver habi tat for waterbi rds.Di sturb-
ance impacts on trumpeter swan nests wi 11 be avoided
as described above.Combined loss of breeding habi-
t at and nest trees wi 11 reduce popul ati ons of water-
birds in the middle basin.However,waterbirds nest
in low densities throughout the middle basin,and
residual impacts represent a regionally insignifi-
cant loss of low-den~ty habitat.
(xii)Other Birds and Small Mammals
Numerical losses of small mammals and breeding birds
are large in the impoundment areas.Additional
losses will be minimized through alignment of the
access road through tundra and low shrub habitats
whi ch support re 1ati ve 1y low numbers and speci es
ri chness.The mi t i gati on measures proposed wi 11
leave large residual impacts,particularly for
speci es restri cted to forest habi tat s.Enhancement
programs.for moose wi 11 increase losses for these
species,in both the lower and middle basins.No
i n-ki nd compensati on on the project si te can be
obtained.Management priorities and conflicts
between mitigation plans prevent specific compensa-
ti on on a scale comparable to loss.However,the
rep 1acement 1 and acqui si ti ons and enhancement mea-
sures descri bed in Mi ti gati on Pl ans 3,4,and 5 wi 11
provi de out-of-ki nd miti gati on through the creati on
and protection of habitat for birds and small mam-
mals of di sturbed and early successional habitats.
4.4.3 -Cost Analysis and Schedules
Schedul es are i ndi cated in the conti nued study and mi ti gati on
plans descri bed in Secti ons 4.4.2{a)and 4.4.2{b)respecti vely.
To develop estimates of compensatory mitigation and study costs,
1982 cost estimates were prepared for each acti vity {Tables
E.3.169 to E.3.175}.These cost estimates were based on unit
cost i nformati on deri ved from past and recent ex peri ence in
Alaska and elsewhere,escalated to arrive at a 1982 cost estimate
appli cable to south-central Al aska.Costs for the miti gati on
program were separated into two categori es:costs incurred
during construction and costs incurred during operation.Operat-
i ng costs are in annual 1982 doll ar amounts averaged over the
50-year li cense peri od.For the major compensatory miti gati on
activities these costs are:
E-3-544
4.4 -Mi ti gati on Pl ans
Construction costs:
Total Constructi on Costs
Downstream aeri al photography
of veget ati on
Browse enhancement programs
Bald eagle nest-~te
cornpensati on
Golden eagle nest-site
cornpensati on
Other raptors nest-si te
cornpensati on
(E.3.170)
(E.3.169)
(E.3.171)
(E.3.172,
E.3.174,&
E.3.175)
(E.3.173)
10,000
$10,340,000
$36,100
$161,200
$9,400
$10,546,700
Total Average Annual Operati ng Costs
These esti mates do not inc 1ude conti ngency
administrative costs.-
Average Annual Operati ng Cost s:
Downstream aeri al photography
of vegetati on
Browse enhancement programs
(E.3 .170)
(E.3 .169)
$1,000
$82,000
$83,000
costs or owner's
The cost analysis and schedule for Mit1gation Plan 5 (compensa-
tion for moose,brown bear,and black bear foraging habitat loss)
are given in Table E.3.169.The controlled burning program in
the middle basin wi 11 require $240,000 from project construction
costs for labor,equipment and logistics,and land leases from
private owners.No firm predictions can be made concerning lands
which may be made available or their cost.It is arbitrarily
assumed that 1/4 of the land to be enhanced through burning would
be leased from private landowners.For the purpose of this cal-
culation,the land is valued at $l,OOO/acre and the lease price
is assumed to be 5 percent of the purchase value per year.The
average annual cost of mai ntenance burni ng to obtai n the optimal
seral ages of vegetation 1s $2,000/year over the 50-year license
period.The clearing program in the lower Susitna basin will
require $9,600,000 from construct10n costs for labor and equip-
ment.It is assumed that all necessary 1ands (esti mated as
16,000 acres,based on current data)can be obtai ned from state
or federal governments through interagency agreement.The aver-
age annual cost of mai ntenance cleari I1g to mai ntai n the opti mal
seral age of vegetati on is $384,000 per year for the 50-year
license period.
E-3-545
4.4 -Mi ti gati on Pl ans
The cost analysis and schedule for Continued Study Plan 2 (aerial
photography to measure changes in vegetati on in the downstream
floodplain)are presented in Table E.3.170.Initial photography
in 1988-89 to establi sh a pre-project baseli ne wi 11 be funded
from project constructi on costs and wi 11 requi re an esti mated
$10,000.Repeat photography will be taken five times in the
li cense peri od (i .e.,every 10 years)at an average annual
operating cost of $1,000.
Five programs of compensatory mitigation for the loss of raptor
nesting locations are costed in Tables E.3.171 to E.3.175.The
provision of modified and artificial nesting locations will be
funded i niti ally as a constructi on cost.As i ndi cated in Miti ga-
ti on Pl an 21,efforts wi 11 conti nue unti 1 100 percent compensa-
ti on in new acti ve nesti ng locati ons has been achi eved.Thi s may
require some funding from operating costs in the first few years
of operation.No firm prediction can be made.However,the
total dollar costs are relatively small:for bald eagle,
$36,100;for golden eagle,$161,200;and for cavity-nesti ng
raptors,$9,400.
Other continued study and mitigation costs,which are an integral
part of project desi gn,are included in project capital costs
(presented in Exhibit D).
4.4.4 -Documentation of Agency Recommendations
Thi s secti on documents agency recommendati ons or mi ti gati on
measures and faci lities made to the Alaska Power Authority.
(i)Access Route Recommendations
The most extensive recommendations concerned the route of
access to the project (USFWS 1983,SHSC 1982,ADF&G 1980).
The agenci es were in agreement on recommendi ng that the
Denali Hi ghway to Watana access route be avoi ded.Spe-
ci fi c concerns addressed the subst anti a 1 di sturbances in
t he Deadman Creek area.USFWS (1983)poi nted out the
importance of that area to calving moose,brown bear denn-
ing,caribou movements,wolf denning,beaver,and bald
eagle nesting.The SHSC (1982)and ADF&G (1980)further
i ndi cated that routes crossi ng the Indi an Ri ver and
through wetlands to the Parks ~ghway,routes on the south
si de of the Susi tna,the Butte Lakes area,and routes
through the Prai ri e Creek-Stephan Lake-Fog Lakes area
should be avoided.Recommended routes include routing
between Watana and Devil Canyon on the north side of the
Sus;tna (USFWS 1982,SHSC 1982,ADF&G 1980)and between
Devi 1 Canyon and Gold Creek on the south side of the river
(USFWS 1982,ADF&G 1980).Additional recommendations on
E-3-546
,-;T--
f'~-
.....
-
-
4.4 -Mitigatirrn Plans
access include rail access to the project site,to the
exclusi on of a road connecti on (USFWS 1982,SHSC 1982),
and consolidation of the access and transmission corridors
(EPA 1981).
The access corri dor from the Denali Hi ghway to Watana was
chosen to provi de timely access to the project site.
Justification for the project design chosen appears in
Chapter 10 descri bi ng the desi gn cri teri a for project
features.Rai 1road access to Devi 1 Canyon has been i ncor-
porated into project design and uses the south side route.
Road access between Watana and Devil Canyon follows the
preferred north-si de route.Rai 1 access alone is not
deemed feasi ble.The Denali Hi ghway-Watana route has been
relocated farther west to avoid the Butte Lake area,and
no project facilities will be located in the Prairie
Creek-Stephan Lake area or in the Fog Lakes area.Further
design changes and alternati ves of the Denali Hi ghway-
Watana route to avoid sensitive areas will minimize im-
pacts to wildlife species.Specifically,the use of
si de-borrow techni ques and restri cti on of road materi al s
borrow sites to areas outside the Deadman Creek area wi 11
minimize habitat loss.No special use areas for moose are
anti ci pated to be made unusab 1e by the access corri dor
(see Section 4.3.3[aJ).No indication that brown bear
denning habitat is in any way limiting has been presented
in ADF&G (1982e).Although no population-level effects on
caribou are anticipated to result from the presence of the
road,the alignment has been moved to the west of most
current major use areas.Continued monitoring of caribou
wi 11 assess the occurrence of unanti ci pated impacts and
allow mitigation through a traffic control program,if
necessary.The wolf dens near the access corri dor are
unlikely to be made unusable,and the Power Authority wi 11
assist the ADF&G in regulating access to active den sites
to av~d disturbance during critical periods as described
in Mi ti gati on Pl an 10.Loss of beaver habi tat wi 11 be
minimized as described in Mitigation Plan 17,and complete
compensation is anticipated downstream for unavoidable
impacts to beaver in Deadman Creek.The access route has
been reali gned to avoi d both destructi on and di sturbance
by traffic of bald e-agle nest 8.The transmission corri-
dor is routed and designed for ease of construction and to
improve mai ntenance and reli abi 1i ty.A common corri dor is
used between Watana and Gold Creek.
E-3-547
4.4 -Mitigation Plans
(ii)Continued Monitoring Recommendations
A need for conti nued moni tori ng has been i ndi cated by
USFWS (1983).Key components of the program recommended
include:(1)inclusion of appropriate federal,state,and
local agency participation;(2)full financial funding by
the Al aska Power Authority;and (3)uti li zati on of the
monitoring program to modify,augment,or delete mitiga-
tion procedures as indicated by ongoing studies.In
parti cular,the USFWS (1983)made recommendati ons for
monitoring and removing floating debris on the reservoir,
continued studies and habitat models for beaver and pine
marten,moni tori ng of mi ti gati on for beaver to insure
levels anticipated,and providing data to assist ADF&G in
regulation of harvest.
The moni tori ng and conti nued studi es programs are de-
scribed in Section 4.4.2(i).The inclusion of federal,
state,and local agencies is indicated in the mitigation
plans where appropriate.In particular,the development
of a modeling approach for management and habitat enhance-
ment of moose includes representation of the USFWS,ADF&G,
and the Uni versity of Al aska.All data from monitori ng
wi 11 be provi ded to the AUF&G wi th recommendati ons regard-
i ng the regul ati on of harvest,whi ch is enti rely thei r
domain.The funding levels of the individual mitigation
plans are presented in Section 4.4.3.The fle~bility of
mi ti gati on pl ans to i denti fy,measure,and respond to
hypothesi zed,unanti ci pated,and current ly unmeasurable
impacts has been stressed.The process by whi ch miti ga-
ti on wi 11 be refi ned and implemented is descri bed in
Section 1.3.The structure for a review group including
agency,project,and subcontractor representation is also
outlined in that section.
Provisions to monitor and to remove reservoir debris
appear as Mitigation Plan 9.Monitoring programs for
beaver are outlined in Section 4.4.2(i).Continued moni-
tori ng of marten i s consi dered an i neffi ci ent use of
avai 1able resources because of confli cts wi th miti gati on
plans for higher priority species (see Section 1)and
because of the lack of jurisdiction of the Power Authority
in regulating the harvest of game on replacement lands.
The modeling program for beaver is described in Mitigation
Pl an 18.
E-3-548
I ,
,..
(i v)
4.4 -Mitigation Plans
(iii)Environmental Briefings Program Recommendation
USFWS (1983)expressed strong support for the Envi ron-
mental Bri efi ngs Program and recommended that it be a
mandatory requi rement for all project personnel before
they begin work on the project.
The Envi ronmental Briefi ngs Program has been descri bed
more completely and has been made a mandatory requirement
for project personnel.
Jay Creek Mineral Lick Recommendation
USFWS (1983)recommended that the reservoi r adj acent to
the Jay Creek mineral lick be closed to boat and float-
plane use.Such restri cti ons wi 11 be imposed on access
duri ng the constructi on phase,as i ndi cated in Mi ti gati on
Pl an 10.
....
-
(v)
(vi)
(vi i)
Garbage Incineration and Fencing Recommendation
USFWS (1983)strongly recommended adequate fenci ng and
garbage i nci nerati on and i ndi cated the need to clearly
post and monitor gate closures.This is treated in detail
in Mitigation Plan 15.
Prohi bi ti on of Hunti ng and Trappi ng Recommendati ons
USFWS (1983)recommended that workers and thei r fami li es
be prohibited from hunting or trapping while working in
the project area.
Miti gati on Pl an 14 descri bes the measures incorporated
into project de~gn to treat the pos~ble impact of over-
harvest of game.The Power Authority has no moral or
legal right to prohibit hunting or trapping on adjacent
state,federal,or private lands.However,control can be
exerci sed over the use of proj ect equi pment and f aci 1i -
ties.Although the Power Authority can have no control
over harvest activities,they wi 11 continue to provide any
data from monitoring investigations to the Alaska Board of
Game to as~st in regulation of hunting and trapping.
Transmission Corridor Recommendations
In addi ti on to consoli dati on of access and transmi ssi on
corridors (treated under access,above),the USFWS (1983)
E-3-549
4.4 -Mitigation Plan
recommended selective clearing,winter and helicopter
constructi on and mai ntenance,and controlled access along
the transmi 5si on li nee
The transmi ssi on corri dor has been re-routed to si mp li fy
constructi on and mai ntenance and to increase reli abi li ty.
Whi le those concerns must dami nate,the chosen desi gn
minimizes overall disturbance.Selective clearing has
been incorporated into the design (see Section
3.4.2[aJ[ii]).High priority species to which summer
clearing would be detrimental (e.g.,eagles and falcons)
wi 11 be protected by disturbance regulations presented in
Mitigation Plan 10.There is no plan at the present time
to control access along the transmi ssi on corri dar.
Fencing would obstruct movements of game and is likely to
be ineffective unless monitored.
E-3-550
REFERENCES -INTRODUCTION
Alaska Department of Fish and Game.1980.Letter from K.B.Schneider
to N.K.Gutcher,R&M Consultants,Inc.November 26.
1982a.Statement of Policy on Mitigation of Fish and Game
Habitat Disruptions.Juneau.
1982b.Testimony of Commissioner R.Skoog to Alaska Power
Authority Board of Directors.April 16.
Alaska Department of Natural Resources.1982.Testimony of
Commissioner John Katz to Alaska Power Authority Board of
Directors.April 16.
Alaska Power Authority.1982.Susitna Hydroelectric Project Fish and
Wildlife Mitigation Policy.
ESSA/WELUT/LGL.1982.Report on Susitna ~droelectric Project
Mitigation Planning Workshop.Environmental and Social Systems
Analysts,Ltd.,Western Energy and Land Use Team,U.S.Fish and
Wil dl ife Servi cej LGL Al aska Research Associ ates,Inc.
Vancouver,B.C.
Susitna Hydroelectric Steering Committee.1981.Letter from A.Carson
to E.Yould,Alaska Power Authority.March 26.
U.S.Fish and Wildlife Service.1979.
E.Yould,Alaska Power Authority.
Letter from G.Hickman to
Septembe r 24.
-
1980.Letter from K.Schreiner to E.Yould,Alaska Power
Authority.June 23.
1981a.Letter to E.Yould,Alaska Power Authority.
December 17.
1981b.Letter from M.Monson to E.Yould,Alaska Power
Authority.December 30.
1982b.Testimony by Regional Director LeRoy Sowl to the Alaska
Power Authority Board of Directors.April 16.
.....
-
1982a •
Authority.
1982c.
Authority.
Letter from J.Morrison to E.Yould,Alaska Power
January 5.
Letter from J.Morrison to E.Yould,Alaska Power
August 17.
r
1982d.Letter to E.Yould,Alaska Power Authority,October 5.
•1983.Letter from K.Bayha to E.Yould,Alaska Power
------Authority,January 14.
E-3-55l
REFERENCES -FISHERIES
Abbad,F.N.1980.Effect of the Quality of Spawners and Rearing
Conditions on the Viability of Fingerlings of the Steelhead
Salmon,Salmo gairdneri.Vopr Ichtiol 20(2)
Acres American Incorporated.1981.Susitna Hydroelectric Project 1980
Geotechnical Report,Task 5:Geotechnical Exploration.Al aska
Power Authority.Anchorage,Al aska.
1982a.Susitna Hydorelectic Project,Feasibility Report.
Final Draft.Vol ume I I,Section 3.Al aska Power Authority,
Mchorage,Al aska.
1982b.Susitna Hydroel ectric Project:Transmi ssion Line
Corridor Screening Closeout Report.Alaska Power Authority.
Anchorage,Al aska.
1982c.Susitna Hydroelectric Project:Transmission Line
Selected Route,Final Report -Figures.Al aska Power Authority.
An c ho rag e,A1as ka •
•1982d.Susitna Hydroelectric Project:Fish and Wildlife
----:Mitigation Policy.Alaska Power Authority.Anchorage,Alaska.11
pp
•1982e.Susitna Hydroelectric Project:Access Plan
----:Recommendation -August 1982.Alaska Power Authority.Anchorage,
Al aska.
Alaska Department of Fish and Game.1972.Cook Inlet King Salmon
Status Report.Alaska Department of Fish and Game.Juneau,
Al aska.
•1974.An Assessment of the Anadromous Fish Populations in the
----'Upper Susitna River Watershed between Devil Canyon and the
Chulitna River.Alaska Department of Fish and Game.Mchorage,
Alaska.
1976.Fish and Wildlife Studies Related to the Corps of
Engineers Devil Canyon,Watana Reservoir Hydroelectric Project.
Al aska Department of Fl sh and Game.Al aska.
•1977.Preauthorization Assessment of the Proposed Susitna
--"Hydroel ectric Projects:.Preliminary Investigations of Water
Quality and Aquatlc Species Composltion,Alaska.
•1978.Preliminary Environmental Assessment of Hydroelectric
----:Development on the Susana River.Al aska Department of Fi sh and
Game.Alaska.Prepared for U.S.Fish and Wildlife Service.
E-3-552
....
-
•1980a.Inventory and Cataloging of Sport Fish Waters of the
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1981b.Phase 1 Final Draft Report Adult Anadromous Fisheries
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•1981c.Phase 1 Final Draft Report Aquatic Habitat and Instream
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______•1981e.Phase 1 Final Draft Report Resident Fish Investigation
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•1981f.Phase 1 Final Draft Report Resident Fish Investigation
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1982a.Phase 1 Final Draft Report Aquatic Studies Program.
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1982c.An Atlas of the Catalog of Waters Important for
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E-3-553
1982e.Prel iminary 1982 Fi sheries Data.Letter from
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1982g.Stream Crossings by Transmission Line,Healy-Ester.
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______•1975b.Contingency Plan for Alyeska Pipeline Service Co.,
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,~
.....
~I
.....
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E-3-603
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APPENDIX E3A
Fish and Wildlife Mitigation Policy
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APPENDIX 3.A
SUSITNA HYDROELECTRIC PROJECT -FISH AND WILDLIFE MITIGATION POLICY
NOVEMBER 1981
REVISED MARCH 1982
REVISED APRIL 1982
1 -INTRODUCTION
The fish and wildlife mitigation aspects of the Susitna project have
been addressed through a Fisheries Mitigation Core Group,a Wildlife
Mitigation Core Group,and a Fish and Wildlife Mitigation Review Group.
The two core groups consisted of staff members of Terrestrial Environ-
mental Specialists,consultants with expertise in special areas (cari-
bou,furbearers,anadromous fish,etc.),and a representative of the
Al aska Department of Fish and Game.The purpose of the two core groups
was to devel opthe technical specifics of the mitigtaion policy and
plans.
The purpose of the Review Group is to review and comment on the results
of the core g"roups.Agencies represented on the Mitigation Review
Group are:
Alaska Department of Natural Resources,
Al aska Department of Fish and Game,
U.S.Fish and Wildlife Service,
U.S.Environmental Protection Agency,
U.S.Bureau of Land Management,and
National Marine Fisheries Service.
A mandate of the Alaska Power Authority (hereinafter called the Power
Authority)charter is to develop supplies of electrical energy to meet
the present and future needs of the state of Alaska.The Power Author-
ity also recognizes the value of our natural resources and accepts the
responsibility of insuring that the development of any new projects is
as compatible as possible with the fish and wildlife resources of the
state and the habitat that sustains them,and that the overall effects
of any such projects will be beneficial to the state as a whole.In
thi s regard,the Power Authority has prepared a Fi sheri es and wn dl ife
Mitigation Pol icy for the Susitna Hydroelectric Project as contained
herein •
2 -LEGAL MANDATES
There are numerous state and federal laws and regulations that specif-
ically require mitig·ation planning.The mitigation policy and plans
contained within this document are designed to comply with the collec-
tive and specific intent of these legal mandates.Following are the
major laws or regulations that require the consideration and eventual
implementation of mitigation efforts.
Protection of Fish and Game (AS 16.05.870)
The Alaska state laws pertaining to the disturbance of streams impor-
tant to anadromous fish address the need to mitigate impacts on fish
and game that may resul t from such acti on.The perti nent porti on of
item (c)from Section 16.05.870 reads as follows:
If the Commissioner determines to do so,he shall,in the
letter of acknowledgement,require the p~rson or governmental
agency to submit to him full plans and specifications of the
proposed construction or work,complete plans and specifica-
tions for the proper protection of fish and game in connec-
tion with the construction work,or in connection with the
use,and the approximate date the construction,work,or use
wi 11 begi n,and shall requi re the person or governmental
agency to obtain written approval from him as to the suffi-
ciency of the plans or specifications before the proposed
construction or use is begun.
National Environmental Policy Act
The National Environmental Policy Act (NEPA)(42 USC 4321-4347)was
designed to encourage the consideration of envi ronmental concerns in
the planning of federally controlled projects.Regulations pertaining
to the implementation of NEPA have been issued by the Council on En-
vironmental Quality (40 CFR 1500-1508:43 FR 55990;corrected by 44 FR
873 Title 40,Chapter V,Part 1500).Items (e)and (f)under Section
1500.2 (Pol icy)of these regulations describe the responsibil ities of
federal agencies in regard to mitigation.
Federal agencies shall to the fullest extent possible:
(e)Use the NEPA process to identify and assess the reasonable alter-
natives to proposed actions that will avoid or minimize adverse
effects of these acti on s upon the qual i ty of the human envi ron-
ment.
(f)Use all practicable means,consistent with the requirements of the
Act and other essential considerations of national policy,to
restore and enhance the quality of the human environment and avoid
or minimize any possible adverse effects of their actions upon the
quality of the human environment.
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Federal Energy Regulatory Commission
Federal Energy Regulatory Commission (FERC)regulations also refer
directly to the need for mitigation actions on the part of the devel-
opers of hydroelectric projects (18 CFR Part 4).The following refer-
ence is quoted from Section 4.41 of the Notice of Final Rulemaking as
it appeared in the November 13,1981,issue of the Federal Register (46
FR 55926-55953)and adopted.Exhibit E of the proposed FERC regula-
tions should include,among other information,
•••a description of any measures or facilities recommended by
state or federal agencies for the mitigation of impacts on
fi sh,wil dl ife,and botani ca 1 resources,or fo r the p rotec-
tion or enhancement of these resources •••
The regulations go on to require details concerning mitigation includ-
ing a description of measures and facilities,schedule,costs,and
funding sources.
Fish and Wildlife Coordination Act (915 USC 661-667)
Item (a)of Section 662 of the Fish and Wildlife Coordination Act
(FWCA)describes the role of the federal agencies in reviewing federal-
ly licensed water projects;
•••such department or agency fi rst shall consult with the
United States Fi sh and Wildl i fe Servi ce,Department of the
Interior,and with the head of the agency exercising adminis-
tration over the wildlife resources of the particular State
wherein the impoundment,diversion,or other control facility
is to be constructed,with a view to conservation of wildlife
resources by preventing loss of and damage to such resources
a's well as provi ding for the development and improvement
thereof in connect i on wi th such water-resource development.
FERC will comply with the consultation provisions of the
FWCA.
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3 -GENERAL POLICIES TO BE CARRIED OUT BY THE APPLICANT
3.1 -Basic Intent of the Applicant
In fulfilling its mandate,an objective of the Power Authority is to
mitigate the negative impacts of the Susitna Project on the fi sh and
wildlife resources.This goal will be achieved through comprehensive
planning during the early stages of project development and through a
program of ongoing consultation with the appropriate resource agencies.
Si nce the Power Authority real i zes that hi ghl y coordi nated pl anni ng
will be necessary to achieve this goal,a decision-making methodology
has been developed to provi de a framework for addressi ng each impact
and the mitigation options available.This methodology outline also
identifies the process for resolving conflicts that may develop between
the Power Authority and the resource agencies.The FERC will resolve-
any disputes which the agencies and the Power Authority cannot resolve.
It is the intent of the Power Authority to negoti ate di rectly and
resolve conflicts with the concerned agencies.
The miti gat ion pl an will be submitted by the Power Authority to the
FERC as a component of the 1 icense appl i cat ion.Pri or to thi s,any
draft mitigation plans will be submitted to resource agencies for
formal review and comment.The final mitigation plan to be implemented
will be stipulated by the FERC.The responsibility for implementation
of the plan will be that of the Power Authority and will be carried out
by the Power Authority or any other organization charged with managing
the project as stipulated by the FERC.
3.2 -Consultation with Natural Resources Agencies and the Public
In order to achieve the above-mentioned goals,it will be necessary to
provide opportunities for the review and evaluation of concerns and
recommendations from the public as well as federal and state agencies.
During the early stages of planning,representatives of state and
federal agenci es will be encouraged to consult with the appl i cant and
the appl i cant I s representatives,as members of the Fi sh and Wil dl i fe
Mitigation Review Group.Additional review and evaluation of the mit-
igation plan will be provided through formal agency comments in
response to state and/or federally administered licensing and permit-
ting programs.
The Power Authority will consider all concerns expressed by members of
the general public and regulatory agencies regarding the mitigation
plan.Input from the public will be given appropriate consideration in
the decision-making process as it pertains to the direction of the mit-
igation effort and the selection of mitigation options.
3.3 -Implementation of the Mitigation Plan
The responsibility for implementation of the mitigation plan rests with
the Power Authority.Prior to impl ementing the plan,an agreement will
be reached as to the most efficient and effective manner in which to
execute the plan.The agreement will determine which organization will
serve to carry out various portions of the plan and will include stip-
ulations to insure adherence to the accepted plan.
The mitigation plan will include a brief statement of each impact
issue,the technique or approach to be utilized to mitigate the impact,
and the goal expected to be achieved through impl ementation of these
actions.
With the realization that a mitigation monitoring team will be neces-
sary to insure the proper and successful execution of the mitigation
plan and to determine its effectiveness,part of the plan will detail
the structure and responsibil ities of such a monitoring body.The
successful organization and operation of a monitoring team will require
both funding and commitments.These matters will be resol ved through
negotiation leading to mutual agreement among the various involved
parties after the mitigation plan is complete and the necessary level
of resources can be more accurately defined.
3.4 -Modification of the Mitigation Plan
As part of the mitigation plan,a monitoring plan will be established,
the purpose of which will be to monitor fish and wildlife populations
during the construction and operation of the project to determine the
effectiveness of the plan as well as to identify problems that were not
anticipated during the initial preparation of the plan.
The mitigation plan will be sufficiently flexible so that,if data
secured during the monitoring of fish and wildlife populations indicate
that the mitigation effort should be modified,the mitigation plan can
be adjusted accordingly.This may involve an increased effort in some
areas where the original plan has proven ineffective,as well as a
reduction of effort where impacts failed to materialize as predicted.
Any modifications to the mitigation pl an proposed by the monitoring
team wi 11 not be implemented without consul tat ion wi th appropri ate
state and federal agencies and approval of FERC.It is the intent of
the Power Authority to reach agreement with the resource agencies con-
cerni ng modifi cat ion of the plan pri or to seek i ng FERC approval.The
Power Authority will seek approval of the resource agencies,with FERC
as the final arbitrator.The need for continuing this monitoring will
be reviewed periodically.The monitoring program will be terminated
when the mitigation goals described in the plan have been achieved or
determined unachievable.Termination will be subject to FERC
approval.
-4 -APPROACH TO DEVELOPING THE FISH AND WILDLIFE MITIGATION PLANS
The deve10ment of the Susitna Fish and Wildlife Mitigation Plans will
follow a logical step-by-step process.Figure E.3.1 illustrates this
process and identifies the major components of the process.Also iden-
tified in this figure are the organizations responsible for each step.
The following discussion is based on Figure 1 and uses the numbers in
the lower right corner of that figure for reference purposes.
The first step in the approach (Step 1)entails the identification of
impacts that will occur as a result of the project.Each impacted
resource and the natu re and extent of the impact wi 11 be defi ned.The
fish and wildlife resources will vary identification and may include a
population,subpopulation,habitat type,or geographic area.The
nature and degree of impact on each respective resource will be predic-
ted to the greatest extent possible.Ths step will be the responsi-
bility of the Core Group of the Mitigation Task Force.
Following the identification of impact issues,the Core Group will
agree upon a logical order of priority for addressing the impact
issues.This will include ranking resources in order of their impor-
tance.The ranking will take into consideration a variety of factors
such as ecological value,consumptive value,and nonconsumptive value.
Other factors may be considered in the ranki ng if deemed necessary.
The impact issues will also be considered in regard to the confidence
associated with the impact prediction.In other words,those resources
that will most certainly be impacted will be given priority over impact
issues where there is 1ess confidence in the impact I s actually occur-
ring.The result of this dual prioritization will be the application
of mitigation planning efforts in a logical and effective manner.The
results of the prioritization process will be reviewed by the Fish and
Wildlife Mitigation Review Group.If additional impacts materialize,
the plan will be modified as discussed in Section 3.4.This could also
include a shift in the prioritization of impacts.
Step 2 is the option analysis procedure to be performed by the Core
Group.The intent of this procedure is to consider each impact issue,
starting with high priority issues,and reviewing all practicable miti-
gation options.
Mitigation for each impact issue will be considered according to the
types and sequence identified by the CEQ (Figure E.3.2).If a proposed
fonn of mitigation is technically infeasible,only partially effective,
or in confict with other project Objectives,additional options includ-
ing project modification will be evaluated.All options considered
will be evaluated and documented;this documentation will include an
identification of the impact issue,mitigation options,and conflicts
(if any)with project objectives.The result of this process will be
an identification and evaluation of feasible mitigation options for
each impact issue and a description of residual impacts.
Step 3 concerns the development of an acceptable mitigation plan.The
feasible mitigation options identified through Step 2,and a descrip-
tion and explanation of those deemed infeasible,will be forwarded to
the mitigation review group for informal agency review and comment.
Any recommendations received from the review group will be considered
by the Power Authority and the Core Group,prior to the preparation of
draft fisheries and wildlife mitigation plans.These draft plans will
be sent to the Fish and Wildlife Mitigation Review Group for comment,
revised and circulated to the agencies for formal review and comment.
The plans will then be revised and submitted to the FERC as a component
of the license application.The final fish and wildlife mitigation
plans to be implemented will be stipulated by the FERC following
discussions with the Power Authority and appropriate natural resource
agencies.
Additional items that may be addressed by the Core Group include an
identification of organizations qualified to execute the mitigation
plan and recommendations concerning the staffing,funding,and respon-
sibilities of the mitigation monitoring team.This will be done in
consultation with the Fish and Wildlife Mitigation Review Group.
Step 4 will be the implementation of the plan as agreed to during
Step 3.This will commence,as appropriate,following the reaching of
an agreement by all parties.
During the implementation of the plan,which will include both the
construction and operation phases of the project until further mitiga-
tion is deemed unnecessary,the mitigation monitoring team will review
the work and evaluate the effectiveness of the plan (Step 5).To
accomplish this goal,the monitoring team will have the responsibility
of assuri ng that the agreed upon pl an is properly executed by the
designated organizations.The team will be provided with the results
of ongoin~monitoring efforts.This will enable the team to determine
in which cases the mitigation plan is effective,where it has proven to
be less than effective,and also in which cases the predicted impact
did not material ize and the proposed mitigation efforts are unneces-
sa ry.The monitori ng team will submit regul a rly schedul ed reports con-
cerning the mitigation effort and,where appropriate.propose modifica-
tions to the plan.If stipulated in the FERC license,such reports
woul d be distributed to FERC and state and federal regulatory agen~
cies.
In the event that plan modificati ons are recommended (Step 6),they
will be reviewed by a Core Group and appropriate options considered
(Step 2).The results of the option analysis will then be passed on to
the Power Authority and the resource agencies for negotiation of modi-
fications to the plan (Step 3).Following the reaching of an agreement
on the modifications.they will be implemented (Step 4)and monitored
(Step 5).Any modifications to the mitigation plan will not be imple-
mentedwithout consultation with appropriate state and federal agencies
and approval of FERC.As discussed in Section 3.4,it is the intent of
the Power Authority to reach agreement with the resource agenices
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concerning modification of the plan prior to seeking FERC approval.
The Power Authority will seek approval of the resource agencies,with
FERC as the final arbitrator.
Following satisfactory implementation of any plan modifications and
documentation of evidence that the go~ls of the modification have been
reached,the mitigation planning process and monitoring will terminate
(Steps 7 and 8).
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APPENDIX E3B
Environmental Guidelines Memorandum
.-
APPENDIX 3.B
SUSITNA HYDROELECTRIC PROJECT
MEMORANDUM
October 25,1982
TO:Dr.John Hayden,Acres American,Inc.
Dr.Richard Fleming,Alaska Power Authority
FROM:Dr.Robert Sener,LGL Alaska Research Associates,Inc.
Dr.Larry Moulton,Woodward Clyde Consultants,Inc.
Mr.Robert Eri ck son,EDAW,Inc.
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SUBJECT:Environmental Guidelines for Facility Siting,Design,
Construction,Operation and Rehabilitation
The attached environmental guidelines are provided for your review and
consideration.They were prepared cooperatively by our three firms and
represent a consensus of our professional judgement.We bel ieve that
these guidelines,if followed,will make a major contribution toward
avoiding,minimizing,rectifying,and reducing adverse impacts of the
project on the environment.
We strongly recommend that these guidel ines be followed for all future
engineering design and construction planning programs of the Susitna
Hydroelectric Project.Furthermore,we urge that the following steps
be taken immedi ately:
1.Provide the guidel ines to all persons responsible for preparing
exhibits or sub-sections of the FERC license application.The doc-
ument should consistently reflect the incorporation of appropriate
environmental protection measures "into the basic thinking under-
lying the project.
2.Make the guidelines available to Phase II contractors as part of a
special communication which emphasizes the importance of integrat-
ing environmental protection strategies into the earliest stages of
engineering design and construction plannning.
Please note that these are only guidelines.Site-specific facility
designs and construction plans should be considered on a case_-by-
case basis to ensure that project requirements are satisfied with
minimal adverse impact to the environment.To achieve this goal,
environmental specialists should work side-by-side with project
engineers in the same design offices,and in the field through pre-
construction siting studies.
SUSITNA HYDROELECTRIC PROJECT
Environmental Guidelines for Facility Siting,Design,
Construction,Operation,and Rehabilitation
Prepared by
lGL Alaska Research Associates,Inc.
Woodward-Clyde Consultants,Inc.
EDAW,Inc.
October 21,1982
A.ALL FACILITIES
1.A SaO-foot minimum-width buffer of undisturbed vegetation should be
maintained between a facility and any stream,lake,or wetland.
2.Siting should minimize requirements for clearing or removal of
veget at ion.
3.Where removal of vegetation is required,organic overburden should
be segregated and stockpiled for use in subsequent rehabilitation.
Stockpiles should be placed in well-drained locations and bermed to
conta in runoff.Depleted or non-operat i ona1 borrow pits shou1 d be
used as overburden storage areas where feasible.
4.Structures shou1 d be consol idated to disturb the minimum necessary
area of ground surface.
5.Design should minimize gravel requirements by avoidance of wet
areas or permafrost zones,structure consolidation,and balanced
cut and fill.
6.Where gravel pads must be used, adequate provlslon for cross-
drainage should be made to avoid impoundment of sheet flow.
7.A minimum distance of 1/2 mile should be maintained between any
facility and the following:
-Salmon spawning area;
-Bald eagle nest;
-Golden eagle nest;
-Brown bear den;
-Black bear den;
-Wolf den;
-Oal1 sheep lambing area;and
-Mineral 1 ick.
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8.Blasting should avoid times and locations which are sensitive to
fish and wildlife.These times and locations should be determined
on a case-by-case basi s by the envi ronmental consultant and in
accordance with resource agency guidel ines.Pr0l'ler s i zi ng and
sequencing of blasting charges can minimize fish and wildlife
impacts.Streamside excavation should not be done by blasting •
Blasting procedures and schedules must be sufficiently flexible to
allow alteration at short notice for the protection of wildlife.
Alaska Department of Fish and Game blasting guidelines should be
followed.
9.Excavation spoil should be disposed of in the future impoundment
area of the dam under construction.Where haul distances prohibit
thi s,spoil shoul d be used in the rehabil itat i on of depl eted or
non-operational material sites,or for solid waste disposal site
.maintenance.Spoil retained for these applications should be
stockpiled in stable,well-drained locations,and bermed to con-
tain runoff.
10.Solid waste disposal sites should be established in stable,well-
drained locations.Siting should utilize existing excavations
such as depl eted upl and borrow pits.Intermittent drai nages,
ice-ri ch soi 1 s,or other erosion-suscepti b1e features shoul d be
avoided.Deposited materi al shoul d be covered daily with non-
silty excavation spoil stockpiled for this purpose at the site.
Solid waste disposal site design and operation should conform with
guidel ines establ ished by the Al aska Department of Envi ronmental
Conservat ion.
11.Facility siting should avoid thaw-susceptible areas (discontinuous
permafrost zones)capable of slumping or thermal erosion.
12.Where hydraulic erosion is unavoidable,appropriate measures
(ranging from filtration fabric to settling ponds)should be
employed,to minimize siltation.
13.Erosion-prone slopes shoul d be ferti 1i zed and dry-seeded wi th a
fast-growing native grass.
14.Equipment,structures,and materials should be removed from a site
prior to rehabilitation.The site should be graded to contours
which are consistent with surrounding terrain and allow complete
drainage with minimal erosion potential.
15.Where it can be demonstrated that erosion is not 1 ikely to be a
problem,restoration should emphasize fertilization and scarifica-
tion,and minimize seeding,to encourage the invasion of native
pl ants from the surroundi ng parent popul at i on.Where seedi ng is
employed,native grasses appropriate to the climate and geography
of the project area should be used •
16.A systematic program to avoid or mitigate project activity-related
impacts should be developed during Phase II.At a mi nimum,this
program should include the following components:
- A Petroleum and Hazardous Substance Plan which sets forth
detailed specifications for training of personnel and for pro-
cedures and equi pment to ensure the safe storage,handl i ng,
transportation,collection,and disposal of petroleLm products
and hazardous substances.This program should include the
preparation of a Petroleum and Hazardous Substances Manual to be
used by all project personnel.Special attention should be
given to the design of this manual so that size,format.and
contents facilitate routine on-the-job use.
-An Environmental Briefings Program to famil iarize project per-
sonnel with envi ronmentally sensitive features of the stipul a-
tions,and specific project ~olicies and restrictions regarding
protection of vegetation,fish,wildlife,and cultural
resources.The Environmental Briefings Program should be com-
bined with the project Safety Program and involve continuing
updates and reviews through regularly-scheduled weekly meetings.
The Environmental Briefings Program should be positive and
informative in nature,and use visual aids to stimulate inter-
est.The program should strive to explain why a certain feature
or organism is vulnerable to disturbance,and therefore,why
protective measures are needed in each case.
17.Storage containers for fuels and hazardous substances should be
located at 1east 1,500 feet from water bodi es and bermed to
contain 110 percent of the maximum volume to be stored.Contain-
ment areas should be lined with impervious material.
18.Project construction and operation activities should be planned
and schedul ed to avoi d or mi nimi ze disturbance to fi sh streams.
Where activities affecting fish streams cannot be avoided (e.g ••
construction of stream crossings),activities should be scheduled
for periods when fish are not present.Where stream crossings are
planned for winter construction.the thalweg,banks,and other
locational features should be identified and staked in the field
prior to snowfall or freeze-up.
B.CONSTRUCTION CAMPS
1.To minimize scavenging by birds and mammals,with resultant
adverse contacts between people and animals,all putrescible
kitchen wastes should be stored indoors in sealed containers,and
incinerated on the same day they are produced.
2.Camp incinerators should be properly sized and operated by trained
personnel to ensure that all putrescible wastes are completely
burned to m;neral ash.Inci nerator capacity shoul d be carefully
specified to accommodate peak camp occupancy.
F-
3.Camp perimeters should be protected with animal-resistant fencing
designed and built to specifications provided by the environmental
consultant.
4.The liquid waste treatment system should be operated by State-of-
Alaska accredited personnel.Greywater must be treated along with
other liquid wastes.A regular effluent sampl ing and testing pro-
gram should be followed to ensure compliance with NPDES and State
of Al aska Wastewater Oi sposal Standards (I8 AAC 72).Eftl uent
test i ng shoul d be conducted by a State-of-Al aska cert ifi ed water
quality laboratory.Effluent discharge to streams should be loca-
ted to achieve maximum dilution.
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5.Wells should be established for potable water withdrawal.If
wells are not feasible at a given location,water should be with-
drawn from lakes.Streams should be considered only as a last
resort,and only after a dete~ination is made on a case-by-case
bas is that fi sh or wil dl ife wi 11 not be adversely affected by
water withdrawal,pa rt icul arly duri ng overwinteri ng and reproduc-
tive periods.Intake structures should be designed to preclude
entrapment or entrainment of fish eggs or larvae.
C.ACCESS ROADS
Routes should avoid wetland and riparian areas,and minimize
stream crossings and encroachments.
Road profile elevations should be minimized and side slopes made
sufficiently gentle to allow free passage of big game.
Road des ign should keep gravel extracti on requi rements to a ml nl-
mum by avoiding wet areas and emphasizing balanced cut and fill.
Where stream crossings cannot be avoided,they should be al igned
at right angles to the stream and located to minimize requirements
for bank cutting and streambed disturbance.Fish spawning and
overwinteri ng areas withi n streams shoul d be avoided by route
adjustments.
Bridges should be installed in preference to culverts or low-water
crossings (fords).Bridge supports should be located outside
active channel s.
1.Road design speeds should be kept to the mlnlmUm consistent with
project requirements,and should not exceed 40 miles per hour.
Lower design speeds allow greater flexibility for alignment
adjustments to avoid environmentally sensitive features,and re-
duce requirements for major road cuts.Lower design speeds also
enable routing to follow higher,drier terrain,thereby reducing
requirements for gravel extraction and fill placement in wetlands.
A 40..,mile-per-hour design speed will increase road safety and
enhance recreational resource potential.-
2.
3.
-4.
5.
~
6.
7.Culverts should be properly sized to accommodate all species and
age groups of fish utilizing that portion of the stream (see
Alaska Department of Fish and Game stream crossing guidelines).
8.Culverts should be placed to conform with the slope of the undis-
turbed streambed at the place of installation,and should not be
perched.
9.low-water crossings should be used only where a stream will sus-
tain infrequent,light traffic.Such crossings should conform to
the slope of the undisturbed streambed and should be constructed
of materials that will preclude water percolating through rather
than over them.
10.Where stream crossings are planned for w"inter construction,the
thalweg,banks,and other 10cationa1 features should be identified
and staked in the field prior to snowfall or freeze-up.Overwin-
tering areas of fish or aquatic mammals must not be disturbed
during winter construction.
11.All access roads not requi red for project operati on or recrea-
tional purposes should be "pu t to bed"as soon as they are no
longer required,if possible during the same season.Drainage
structures should be removed and the roadbed recontoured to a
stable configuration providing proper drainage.Rehabi1 itation
sho~d in1cude scarification,fertilization,and blockage with a
berm followed by a cut.Erosion-prone locations should be seeded
with fast-growing native grasses.Where impoundment of sheet flow
has occurred,non-operational roads should be structurally altered
to restore normal flow.
12.Road dust control should ut i1 i ze water rather than oil or other
synthetic compounds.Water withdrawal procedures and sources for
dust control shou1 d be approved on a case-by-case basis by envi-
ronmental personnel following site-specific inspection.
13.Grading or other road maintenance activities should not push mate-
rial into streams.Culverts should be checked periodically and
kept free of ice and debris to avoid blocking flows.Special
attention to culverts is required immediately prior to,during,
and following spring break-up.
D.MATERIAL SITES
1.A detailed,site-specific mlnlng plan should be prepared for each
borrow operation.Design should be·an interdisciplinary team
effort involving civil engineers and environmental specialists
experienced in design,construction,and permit requirements.
Mining plans should include all roads,facilities,mining tech-
niques,schedules,and rehabilitation procedures.
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Borrow areas requi red for dam and ancill ary facil ity construction
should be sited in the future impoundment area of the dam under
construction.
Siting of borrow areas outside ~he impoundment zone should place
first priority on well-drained upland locations.Second priority
consideration should be given to first-level terrace sites.
Active floodplain and streambed sites should be avoided unless
they are within the impoundment area of the dam under construc-
tion.Stockpiling within active floodplains should be prohibited.
Floodplain gravel mining should follow the guidelines set forth in
the u.s.Fish and Wildlife Service "Gravel Removel Guidelines
Manual for Arctic and Subarctic Floodplains,"1980.
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4.All material sites should be developed in phases by aliquots.The
phases should be prioritized to save until last those portions of
the site which are more sensitive from an environmental stand-
point.
5.First-level terrace sites outside the impoundment zone should be
located on the inactive side of the floodplain and mined by pit
excavation rather than by shallow scraping.Excavations should be
separated from the active floodplain by a 500-foot buffer of
undisturbed,vegetated terrain.
6.If wet processing is required,water withdrawal and discharge
locations should be carefully sited to minimize fish and wildlife
di stu rbance.Drawdown in overwi nteri n9 pool s used by fi sh or
aquatic mammals,and any disturbance to spawning areas,must be
avoided.Water intake structures should be designed to preclude
entrapment or entrainment of fish eggs or larvae.Gravel washing
should employ recycled water.If pit dewatering is required
because of pondi ng or wet processi ng,settl i ng poi nds shoul d be
designed,operated,and monitored to ensure that NPDES standards
for discharge are achieved.Settling ponds should be designed and
sited to avoid fish entrapment.Water discharge should be direc-
ted in a manner that will minimize erosion.Energy dissipators
should be used where necessary.
7.Abandoned access roads,camp pads,and airstrips should be used
wherever feasible as material sources for operations,in lieu of
expanding existing sites or initiating new ones.Where riprap is
requi red,materi al produced dur i ng excavat i on of the powerhouse,
galleries,and tunnels should be used if feasible.
8.Material site design features should facilitate restoration.
Sites should have irregular boundaries,including projections of
undisturbed,vegetated terrain into the site.Slopes should
incorporate a di vers ity of contours created duri ng actual excava-
tion,rather than during restoration.
9.Where ponding will occur,as in first-level terrace sites,irregu-
lar boundaries and slope contours should be accentuated.Islands
of undisturbed vegetated terrain should be left within the peri-
meter of the operational site.
10.Organic overburden,slash,and debris stockpiled during clearing
should be distributed over the excavated area prior to fertiliza-
tion.This includes sites which have ponded.
11.Once operational material sites are depleted or no longer re-
qui red,they shoul d be rehabil itated by the end of the next
growing season following last use.
E.TRANSMISSION CORRIDORS
1.Where they are not adjacent to an existing road,transmission
corridors should be constructed by helicopter support to avoid
unnecessary clearing of vegetation.In tundra locations where
clearing is not required for access,winter construction on a snow
base may be an acceptable substitute for helicopter-supported con-
struction,provided Rolligon or flat-tread Nodwell-type vehicles
are used.Transmission corridor development should avoid creating
an alternative access route for all-terrain vehicles.
2.Transmission line additions should be made adjacent to established
transmission corridors.Where transmission lines have a common
destination,they should follow a common route.
3.Transmission towers should not be placed in active floodplains and
should avoid streams and lakes by a minimum 500 feet.
4.Herbicides should not be used for vegetation control along trans-
mission corridors.
5.Transmission corridors shoul d follow the forest edge (i .e.,the
transition zone between forest and shrub or forest and tundra),
and avoid crossing wetlands.
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APPENDIX E3C
Preliminary List of Plant Species
Upper and Middle Susitna River
APPENDIX 3.C:PRELIMINARY LIST OF PLANT SPECIES IDENTIFIED IN SUMMERS
OF 1980 AND 1981 IN THE UPPER AND MIDDLE SUSITNA RIVER
BASIN*(U),THE DOWNSTREAM FLOODPLAIN (D),AND THE
INTERTIE (I)(AFTER MCKENDRICK ET AL.1982)
Pteridophyta
Aspidlaceae
Dryopterls di latata (Hoffm.)Gr~y
Dryopterls fragrans (L.)Schott
Gymnocarplum dryopterls (L.>Newm.
Athyrfaceae
Athyrium fi lix-femina (L.)Roth
Cystopterls fragilis (L.)Bernh.
Cystopteris montana (Lam.)Bernh.
Matteuccia struthiopteris (L.)Todaro
Woodsla alpina (Bolton)S.F.Gray
Equisetaceae
Equisetum arvense L.
Equlsetum fluviatile L.ampl.Ehrh.
Equisetum palustre L.
Equlsetum pratense L.
Equlsetum sllvaticum L.
Equisetum varlegatum Schleich.
Eguisetum sp.
Isoetaceae
Isoetes muricata Our.
Lycopod i aceae
Lycopodium alplnum L.
Lycopodium annotlnum L.
Lycopodium clavatum l.
Lycopodium complanatum L.
Lycopodium selago L.ssp.salago
Thelypterldaceae
Thelypteris phegopterls (L.)Siosson
Gymnospermae
Cupressaceae
Juniperus communis L.
Pln~ceae
Picea glauca (Moench)Voss
Picea mariana (Mil I.>Britt.,
Sterns &Pogg.
Monocotyledoneae
Cyperaceae
Carex aquatilis Wahlenb.
Carex bigelowil Torr.
Carex capl Ilaris L.
Carex canescens l.
Carex conclnna R.Br.
'Shield fern
Fragrant shield fern
Oak fern
Lady fern
Frag I Ie fern
Mountain fragi Ie fern
Ostrich fern
Alpine woodsia
Meadow horseta i I
Swamp horseta II
Marsh horseta II
Meadow horseta i I
Woodland horsetai I
Variegated scouring-rush
Horsetail
Qu illwort
AlpIne clubmoss
St i ff c Iubmoss
Running clubmoss
Ground cedar
Fir cl ubmoss
Long beech fern
Common juniper
White spruce
Black spruce
Water sed!:je
Bigelow sedge
Hairlike sedge
SII very sedge
Low northern sedge
U D
U
U 0
U 0
U
U
o
U
U
U o
U 0
U
U 0
U
U
U
U
U
U
U
U
U 0
U
U
U
U
U 0
U
APPENDIX 3.C (Page 2)
Carex fl f Ifol ia Nutt.
Carex garberl Fern.
Carex I imosa L.
Carex lollacea L.
Carex media R.Sr.ex Richards.
Carex "iiieiii'i>ranacea Hoc k.
Carex podocarpa C.S.Clarke
Carex rhynchophysa C•.A.Mey.
Carex saxati I is L.
Carex spp.
ETeOCharis sp.
Eriophorum angustlfol ium Honck.
Erlophorum scheuchzeri Hoppe
Eriophorum vaglnatum L.
Er lophorum sp.
Sclrpus microcarpus Presl.
Trichophorum caespitosum (L.)Hartm.
Gramlneae (Poaceae)
Agropyron boreafe (Turcz.)Drobov
Agropyron canlnum (L.)Beauv.
Agropyron macrourum (Turcz.)Drobov
Agropyron sp.
Agrostis scabra Wl lid.
Agrostls sp.
Alopecurus alpinus Sm.
Arctagrostis latifolla (R.Sr.)Grlseb.
Beckmannia syzlgachne (Steud.)Fern
Calamagrostls canadensis (Mlchx.)Beauv.
Calamagrostis pur¥urascens R.Br.
Clnna latltolla (rev.)Griseb.In Ledeb
~onia Intermedia Vasey
Deschampsia atropurpurea (Wahlenb.>
Scheele**
Deschampsia caestitosa (L.)Seauv.
Festuca altaica rin.
Festuca rubra L.Co I I.
Hlerochloe alplna (Swartz)Roam.&Schult.
Hierochloe odorata (L.l Wahlenb.
Phleum commutatum Gandoger
Poa alplna L.
Poa arctlca R.Sr.
"flO'a pa Iustr Is L.
irlisetum spicatum (L.l Richter
Irldaceae
~setosa Pel las
Juncaceae
Juncus arctlcus Wi1 Id.
Juncus castaneus Sm.
Juncus drummondl I E.Mey.
Juncus mertenslanus Bong.
Juncus trlglumls L.
Luzula campestrls (L.)DC.ex DC.
&Lam.**
Luzula confusa Ltndeb.
Luzula multiflora (Retz.>LeJ,
Luzula parviflora (Ehrh.)Desv.
Luzufa tundrlcola Gorodk.
Luzula wahlenbergli Rupr.
,'''''''
..-
-
-
APPENDIX 3.C (Page 3>
LII iaceae
Lloydla serotina (L.)Rchb.
Streptopus amplexlfolius (L.>DC.
Tofieldia coccinea Richards
Tofieldia pusl Ila (Mlchx.>Pers.
Veratrum vir/de Ait.
Zygadenus elegans Pursh
Orch I daceae
Listera cordata (L.>R.Sr.
Platanthera convallarlaefolia
(Fisch.>Lindl.
Platanthera di latata (Pursh>Llndl.
Platanthera hyperborea (L.)Lindl.
Potamogetomaceae
Potamogeton epihydrus Rat.
Pota~eton filiformls Pers.
Potamogeton gramineus L.
Potamogeton pertoliatus L.
Potamogeton robblnsl r Oakes
Sparganiaceae
Sparganium angustifollum Michx.
DIcotyledoneae
Ara Ilaceae
Echinopanax horridum (Sm.>Decne.
&Planch.
Setu I aceae***
Alp II Iy
Cucumber root
Northern asphodel
Scotch asphode I
Fa Ise he IIebore
Elegant death camas
Twyblade
Northern bog-orchis
White bog-orchis
Northern bog-orchls
Nutta II pondweed
F iii form pondweed
Pondweed
Clasping-leaf pondweed
Robbins pondweed
Narrow-leaved burreed
Dev!I's club
u
U D
U
U
U
U
u
U
U
U
U
U
U
U
U
U D I
..-
-
Alnus crispa (Ait.>Pursh
Alnus sinuata (Reg.)Rydb.
Alnus tenulfol ia Nutt.
Alnus Spa
~a glandulosa Mlchx.
Setu Ia nana L.
Betula occidental is Hook.
Betula papyrifera Marsh.
Boraginaceae
Mertens/a pan leu lata (Alt.>G.Don
Myosotls alpestris F.W.Schmidt
Ca II i tr Ichaceae
Cailitriche hermaphroditica L.
Cailltriche verna L.
Campanulaceae
Campanula lasiocarpa Cham.
Capr I to II aceae
Llnnaea borealis L.
Sambuons callicarpa
Viburnum edule (Michx.>Raf.
American green alder U
SI tka al der U D
Thlnleat alder D
Alder
Resin birch U
Dwarf arctic birch U D
Water birch U
Paper birch U D
Tall bluebell U D I
Forget-me-not U
Water starwort U
Vernal water starwort U
Mountain harebel I U
Tw i n-f lower ·U
Pacific red elder
High bush cranberry U D
APPENDIX 3.C (Page 4l
Caryophy II aceae
Mlnuartla obtusiloba (Rydb.)House
Moehringla laterlfolla (L.l Fenzl
S ilene acau I Is L.
Stellaria crasslfolla Ehrh.
Stellarla sp.
Wilhelmsla physodes (Fisch.l McNeill
Composltae (Asteraceael
Achillea borealis Bong.
AchIllea slblrlca Ledeb.
Antennaria alplna (L.l Gaertn.
Antennarla monoceghala DC.
Antennarla rosea reene
Arnica amplexicaul Is Nutt.ssp.prima
Maguire
Arnica chamissonls Less.(1l
Arnica friglda C.A.May.
Arnica lesslngll Greene
Artemisia alaskana Rydb.
Artemisia arctlca Less.
Artemisia tllesll Ledeb.
Aster slblrlcus L.
Erigeron acrls subsp.polltus (L.l
(E.Frlesl Schlnz &Keller
Erigeron humills Graham
Erigeron I onchophy I Ius Hook.
Erigeron purpuratus Greene
Hleraclum trlste Wilid
Petasltes frlgldus (L.l Franch.
Petasites saglttatus (Banks)Gray
Petasltes sp.
Saussurea angustifolla (Wllld.l DC.
Senecio atropurpureus (Ledeb.l Fedtsch.
Senecio lugens Richards.
Senecio sheldonensls Pors.
Senecio triangularis Hook
Senecio sp.
Sol idago multlradiata Ait.
Taraxacum sp.
Cornaceae sp.
Cornus canadensis L.
Crassu laceae
Sedum ~(L.1 ScoP.
Cruclferae (Brassicacea)
Oraba aurea Vahl
car:damTri'ebe III d I fo Iia L.
Cardamlne pratensis C.
Cardamlne umbel lata Greene
Draba nlvalls CllJebl
Draba steno Ioba Ledeb.
~a nudlcaulis (l.)Regel
01 apens Iaceae
Olapensia lapponica L.
Alpine sandwort
Grove Sandwort
Moss camp Ion
Chickweed
Starwort
Merckia
Yarrow
Siberian yarrow
AI pine pussy toes
Pussy toes
Pussy toes
Arnica
Arnica
Arnica
Arnica
AI aska wormwood
Wormwood
Wormwood
Siberian aster
Fleabane
Fleabane da I sy
Oa isy
Fleabane
Wooly hawkweed
Arctic sweet coltsfoot
Arrowleaf sweet coltsfoot
Sweet coltsfoot
Saussurea
Ragwort
Ragwort
Sheldon groundsel
Ragwort
Ragwort
Northern goldenrod
Dandelion
Bunchberry
Roseroot
Draba
Alpine blttercress
Cuckoo f lower
Blttercress
Rockcress
Rockcress
Parrya
Olapensla
u
u
uu
U 0
U D
U
U
U
U
D
U
U
U
U
U D
U D
I
U
D
U
U
U
0
U
U
U
U
(",",'
U D
U
U D I
U
U
U
U
U
U
u
-
-
-
,..,..
,'-
APPENDIX 3.C (Page 5>
Droseraceae
Drosera rotundlfolla L.
EIaeagn aceae
Shepherdia canadensis (L.>Nutt.
Empetraceae
Empetrum nlgrum L.
Ericaceae
Andromeda polifolia L.
Arctostaphylos alpina (L.>Spreng.
Arctostaphylos rubra (Rehd.&Wilson)Fern.
Arctostaphylos uva-ursl (L.>Spreng.
Cassiope tetragona (L.>O.Don
Ledum decumbens (Alt.>Sma I 1***
Ledum groenlandlcum Oeder
Ledum sp.
l:OT'Seleuria procumbens (L.)Desv.
Menziesia ferruglnea Sm.
Oxycoccus mlcrocarpus Turcz.
Rhododendron lapponicum (L.>Wah'lenb.
Vacclnlum caespltosum Michx.
Vaccinlum uliglnosum L.
Vacclnlum vltls-Idaea L.
Vaccinium sp.
Fumarl aceae
Corydal Is pauclflora (Steph.)Pers.
Gent Ianaceae
Gentiana glauca Pall.
Gentiana propinqua Richards.
Menyanthes trlfoliata L.
SwertJa perennls L.
Geran laceae
Geranium erlanthum DC.
Haloragaceae
Hlppurls vulgaris L.
Legumlnosae (Fabaceae)
Astragalus aborlglnum Richards.
Astragalus alpinus L.-*
Astragalus umbel latus Bunge
Hedysarum alplnum L.
Luplnus arctlcus S.Wats.
Oxytropls campestrls (L.>DC.
Oxytrop Is hudde Ison II Pros I Id
Oxytropls maydeiliana Trautv.
Oxytropls nlgrescens (Pall.>Fisch.
Oxytropls vlsclda Nutt.
Sundew
Soapberry
Crowberry
Bog rosemary
Alpine bearberry
Red-fruit bearberry
Bearberry
Four-angle mountain
heather
Northern Labrador tea
Labrador tea
Labrador tea
AIp J ne aza Iea
Menzlesla
Swamp cranberry
Lap land rosebay
Dwarf bl ueberry
80g blueberry
Mountain cranberry
81 ueberry
Few-f lowered coryda lis
Glaucous gentian
Gentian
Buckbean
Gentian
Northern geranium
Common ma resta II
Milk-vetch
Milk-vetch
Mil k-vetch
AIpine sweet-vet ch
Arctic lupine
Field oxytrope
Huddelson oxytrope
Maydel I oxytrope
81acklsh oxytrope
VI sc i d oxytrope
u 0 I
u
u
u
u
u
u
u
u
o
u
U D
U
U
U 0
U
U
U
U D
U
U
U
U
U D
U
U D
U
D
U
U
U
U
APPENDIX 3.C (Page 6)
Lentibularlaceae
PlnQuicula vi I losa L.
Otricularla vulgaris L.
Myr i caceae
Myrica ~L.
Nymphaeaceae
Nuphar polysepalum Engelm.
Onagraceae
Clrcaea alpina L.
Epilobium angustifol ium L.
Epilobium latifol ium L.
Epllobium palustre L.
Orobanchaceae
Boschniakia rosslca (Cham.&Schlecht.
Fedtsch.
Po lemon i aceae
Polemonlum acutiflorum Wi lid.
Po Iygonaceae
Oxyria digyna (L.)Hi II
Polygonum bistorta L.
Polygonum viviparum L.
Rumex arcticus Trautv.
Rumex sp.
Portulacaceae
Claytonia sarmentosa C.A.Mey.
Primulaceae
Androsace chamaejasme Hult.
Dodecatheon frigldum Cham.&Schlecht.
Primula cunelfol ia Ledeb.
Trlentalis europaea L.
Pyrolaceae
Moneses uniflora (L.)Gray
Pyrola asarifolia Michx.
Pyrola grandiflora Radius
Pyrola minor L.
Pyrola secunda L.
Pyrola sp.
Ranunculaceae
Aconitum delphinifollum DC.
Actaea rubra (Alt.)Wi lid.
Anemone narcissiflora L.
Anemone parviflora Michx.
Anemone richardsonl I Hook
Anemone sp.
Caltha leptosepala DC.
Ha i ry butterwort
Common bladderwort
Sweet ga Ie
Yellow pond Illy
Enchanter's nightshade
Fireweed
Dwarf f i reweed
Swamp willow-herb
Poque
Jacob's ladder
Mountain sorrel
Meadow bistort
Alpine bistort
Arctic dock
Dock
Spr i ng-beauty
Androsace
Northern shooting star
Wedge-leaf primrose
Arctic starflower
Single del ight
Liverleaf wintergreen
Large-flower wintergreen
Lesser wintergreen
One-sided wintergreen
Wintergreen
Monkshood
Baneberry
Anemone
Northern an emone
Anemone
Anemone
Mountain marsh-marigold
u
u
U D I
U
D
U 0
U 0
U
U D I
U D I
U
U
U
U
U
U
U
U
U D
U D
D
U
U
U D
U
D
U
U
U D
U
.....
.-
-
-
APPENDIX 3.C (Page 7)
Delphinium glaucum S.Wats
Ranunculus confervoides (E.Fries)E.Fries
Ranuncu I us macoun i 1 Sr I tt.(may be
B.!..pacificu5 or something simi lar)
Ranunculus nlvalls L.
Ranunculus occidental Is Nutt.
Ranunculus pygmaeus Wahlenb.
Ranunculus sp.
Thallctrum alpinum L.
Thallctrum sparslflorum Turcz.
Rosaceae
gryas drummondi I Richards.
~integrifol ia M.Vahl.
gryas octopetala L.
-!!:!!!!.macrophy I I um Wi I d.
Geum rossil (R.Sr.)Sere
~kea pectinata (Pursh)Ktze.
Potent!I la biflora WI lid.
Potentilla fruticosa L.
Potent!Iia hyparctlca Malte
Potent!I la palustrls (L.)Scop.
Rosa acicularls Lindl.
Rubus arctlcus L.
Rubus chamaemorus L.
Rubus idaeus [.
Rubus pedatus Sm.
Rubus sp.
~rsorba stiputata Raf.
Sibbaldia procumbens L.
Sorbus scopullna Greene
Spiraea beauverdlana Schneid.
Rublaceae
Ga I ium berea Ie L.
Ballum trifldum L.
Balium trlflorum Mlchx.
Sa II caceae***
Larkspur
Water crowfoot
Macoun buttercup
Snow buttercup
Western buttercup
Pygmy buttercup
Buttercup
Arctic meadowrue
Few-flower meadowrue
Drummond mountaln-avens
Dryas
White mountain-avens
Avens
Ross avens
Luetkea
Two-flower cinquefoil
Shrubby cinquefoil
Arctic cinquefoi I
Marsh cinquefoi I
Prickly rose
Nagoon berry
Cloudberry
Raspberry
Five-leaf bramble
Raspberry
Sitka burnet
Sibbaidia
Western mountain ash
Beauverd sp I rea
Northern bedstraw
Small bedstraw
Sweet-scented bedstraw
u
D
uu
u
u
u
U D
U D
U
U
U
U
U
U
U
U D
U D
U D
U
U D
U
U
U
U
U D
U
U
D
.....
~,
.....
-
Populus balsamifera L.
Populus tremuloides Mlchx.
Salix alaxensis (Anderss.)COY.
Salix arbusculoides Anderss.
5"ilTTX arct i ca Pa I I.
Sa IIx bare Iay I Anderss.
Sa I ix brachycarpa Nutt.
Sal Ix fuscescens Anderss.
Salix glauca [.
Salix lanata L.ssp.richardsonll
~ok)A.Skwortz.
Salix monticola Bebb
Sal ix novae-angl iae Anderss.
Sa I i x ph I ebophy IIa Anderss.
Salix planifolia Pursh ssp.planifolla
Salix planlfolla Pursh ssp.pulchra
--rcham.)Argus
Sal ix polaris Wahlenb.
~reticulata L.
Salix rotundifolia Trautv.
Sal ix scouleriana Barratt
Salix sp.
Balsam poplar (or cottonwood)U D
Quaki ng aspen U
Feltleaf wil low U D
Lit t Ietree wIII ow U D
Arctic wi flow U
Barclay wi Ilow U
Barren-ground wi I low U
AIaska bog wIii ow U D
Grayleaf wit low U
Richardson willow U
Park willow U
Tall blueberry wi Ilow U D
Skeleton leaf willow U
Planeleaf wil low U
Diamondleaf wil low U
Polar willow U
Netleaf wil low U
Least wi Ilow U
Scouler wll low U
Willow UD
APPENDIX 3.C (Page B)
Santa/aceae
Geocaulon I ivldum (Richards.)Fern.
Saxl fragaceae
Boyklnia richardsonli (Hook.)Gray
Leptarrhena pyrol ifolla <D.Don)Sere
Parnassla palustris L.
Parnassia kotzebue I Cham &Schlecht.
Parnassia sp.
Ribes hudsonlanum Richards.
Ribes laxiflorum Pursh (may be~.
glandulosum)
Ribes trlste Pal I.
~raga bronchial is L.
Saxifraga davurlca Wilid.
Saxifraga follosa R.Sr.
Saxifraga hieraclfolia Wa/dst.&KIt.
Saxifraga Iyall il Engler
Saxlfraga opposltifolla L.
Saxlfraga punctata [.
Saxl fraga serpy III fo I i a Pursh
Saxifraga trlcuspldata Rottb.
Scrophulariaceae
Castilleja caudata (Pennell)Rebr.
Mlmulus guttatus DC.
PedlcularJs capitata Adams
Pedicularis kanei Durand
Pedlcularls labradorica WirsIng
Pedicularis parvlflora J.E.Sm.yare
parvlflora
Pedicularls sudetlca Willd.
Pedlcularis verticlilata L.
Pedicular[s sp.
Veronica americana
Veronica wormskjoldli Roem.&Schult.
Umbel I Iferae (Aplaceae)
Angelica lucida L.
Heracleum lanatum Mlchx.
Valerianaceae
Valeriana capltata Pal I.
Vlolaceae
Viola eplpslla Ledeb.
~langsdorffl[Fisch.
vroTci"blf lora [.
Viola sp.
Nonvascular Plant Species
Lichens
Cetraria cucul lata (Bel I.)Ach.
Cetraria islandica (L.)Ach.
Cetraria nivalis (L.)Ach.
Cetraria richardsonii Hook.
Cetraria sp.
Cladonla alpestrls (L.)Rabenh.
Sanda Iwood
Richardson boyklnia
Leather-leaf saxifrage
Northern Grass-of-Parnassus
Kotzebue Grass-of Parnassus
Grass of Parnassus
Northern black currant
Trailing black curr:ant
Red currant
Spotted saxifrage
Saxi frage
Fol iose saxIfrage
Hawkweed-leaf saxifrage
Red-stem saxIfrage
Purple mountain saxifrage
Brook saxifrage
Thyme-leaf saxifrage
Three-tooth saxifrage
Pale Indian paintbrush
Yellow monkey flower
Capitate lousewort
Kane lousewort
Labrador lousewort
Lousewort
Lousewort
Whorled lousewort
Lousewort
Alpine speedwell
Wild celery
Cow parsni p
CapItate valerian
Marsh violet
Violet
Violet
VIolet
I~""
U
U
U
U
U
0
U 0
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U 0
u
U
U
U
U
U
U
U
U
F'"
I
-
,f!ItiiiM,
APPENDIX 3.C (Pege 9>
Cladonla mitis Sandst.
Cladonla ranglferlne (L.>Web.
CIadon Ie sp.
Dactyllne erctica (Hook.>Nyl.
Haema1"omma sp.
[obarla Ilnlta (Ach.>Rabh.
Neihroma sp.
Pe "gera·sp.
Rhizocarpon geogrephlcum (L.>DC.
Stereocaulon paschele ([.>Hoffm.
Thamnolle vermlcularls {Sw.>Schaer.
Umbilicaria sp.
Mosses
C limacium sp.
Hypnum spp.and other feather mosses
Paludelle sguerrose (Hedw.>8rld.t
POI:rrlchum sp.Ptl~ium crlsta-castrensls (Hedw.>DeNot.
Rhacomltrlum sp.
Sph8gnum sp.
Re I ndeer moss
Knight's plume
u
uu
u
u
D
uu
u
U D
U
U
U
U
U
U D
U
U D
U D
.-
I
*Vascular plant species nomenclature according to Hutten (1968>except where
noted.Lichen nomenclature according to Thomson (1979>.Moss nomenclature
according to Conerd (1979>.
**Nomenclature according to Welsh (1974>.
***Nomenclature according to Viereck and Little (1972>.
t NomenClature according to Crum (1976>•
l"'-
I
.....
r-
I
"'"'
APPENDIX E3D
Preliminary List of Plant Species
Intertie Area
APPEND IX 3.0
PRELIMINARY LIST OF PLANT SPECIES IDENTIFIED DURING 1981 IN THE
INTERTIE PROJECT AREA (FROM COMMONWEALTH 1982)"
Pter idophyta
Aspidlaceae
....
....
r
Dryopteris di latata subsp.americana
Dryopteris fraQrans
Gymnocarpium dryopteris
Athyriaceae
Matteuccia struthiopteris
Equ i setaceae
Eguisetum sp.
Eguisetum silvaticum L.
Gymnospermae
Cupressaceae
Juniperus communis
Pinaceae
Picea glauca
Picea mariana
Monocotyledoneae
Cyperaceae
Carex spp.
EriOj)horum sPp.
Gramineae
Calamagrostls canadensis
Ir idaceae
~setosa
Sh ield fern
Fragrant shield-fern
Oak-fern
Ostrich fern
Horsetai I
Woodland horsetai I
Common JunIper
White spruce
Black spruce
Sedge
Cotton grass
BlueJoint
Wi Id Flag
APPENDIX 3.D:(Page 2)
Monocotyledoneae (Cont'd)
Li II aceae
Lloydla serotlna
Streptopus amplexlfollus
Tofleldla pusilia
Veratrum virlde subsp.eschscholtzi I
Zygadenus elegans
Orchidaceae
Ltstera cordata
Platanthera hyperborea
DI coty ledoneae
Ara II aceae
Oplopanax horrldum
Betu laceae
AI nus cr i spa
Alnus slnuata
~a glandulosa
Betu la nana
Betula papyrifera
Boraglnaceae
Mertensla pan leu lata
Campanul aceae
Campanula lasiocarpa
CaprI fo Ilaceae
Linnaea boreal is
Sambucus ca II I carpa
VI burnum edu Ie
Caryophy IIaceae
Stellarla crassifolla
Moehringia laterlflora
Alp Illy
Twisted-stalk
Scotch asphodel
False hellebore
White camas
Twayb lade
Bog orch Is
Dev!I 's Ctub
American green alder
Sitka alder
Resin birch
Dwarf arctic birch
Paper birch
Bluebell
Bellflower
Twin-flower
Pacific red elder
High bush cranberry
Chickweed
Grove sand wort
.-
....
I
I
APPENDIX 3.0:(Page 3)
Dicotyledoneae (Cont'd)
Composltae
ArnIca trlgida
Artemisia aretica subsp.arctlca
Artemisia tilesii subsp.unalaschcensis
Aster siblrleus
Erigeron acris subsp.poJitus
E.purpuratus
~tasltes trlgidus
Saussurea angustltolla
Soeneclo sp.
Seneei 0 Jugens
Senecio triangularis
Cornaceae
Cornus canadensis
Crassu Iaceae
Sedum~
Cruclterae
Oraba aurea
~ani:idTcaulis
Diapensiaceae
DJapensia lapponica
Droseraceae
Drosera rotunditolia
E laeagnaceae
Shepherdia canadensis
Empetraceae
Empetrum nlgrum
Arnica
Wormwood
Wormwood
Siberian aster
FI eabane
Fleabane
Arct ic sweet
co Its toot
Saussurea
Ragwort
Ragwort
Groundsel
Bunchberry
Roseroot
Rockcress
Parrya
Diapensla
Sundew
Butta loberry
Crowberry
APPEND IX 3.0:(Page 4)
Dicotyledoneae (Cont1d)
Erlcaceae
Arctostaphylos alplna
Arctostaphylos rubra
Arctostaphylos uva-ursl
Casslope tetragona
Ledum decumbens
Ledum groenlandlcum
~Ieurla procumbens
Menziesla ferruglnea
Rhododendron lapponlcum
Vacclnlum ullglnosum
Vacclnlum vltls-idaea
Fumariaceae
CorydalIs pauclflora
Gentlanaceae
Menyanthes trlfoliata
Swertla perennls
Geranlaceae
Geranium erlanthum
Legumlnosae
Hedysarum alplnum subsp.americanum
Luplnus arctlcus
Oxytropls nigrescens
Myrlcaceae
Myrica~
Onagraceae
Ep I loblum angustlfollum
Epiloblum latlfollum
Orobanchaceae
Boschnlakia rosslca
Alpine bearberry
Red-fruit bearberry
Bearberry
Four angle mountaIn
heather
Northern Labrador
tea
Labr ad or tea
Alpine azalea
Rusty menzlesl a
Lap Iand rosebay
Bog blueberry
Mountain cranberry
Few-f lowered
corydall s
Buckbean
Gentian
Cranesblll
Alplne-sweet-vetch
Arctic lupine
Blackish oxytrope
Flreweed
River beauty
Poque
-
..-
-
.-
APPENDIX 3.0:{Page 5)
01 cety I edonea8 (Con t •)
P-o Iemon I aceae
Polemonlum acutlflorum
Polygonaceae
Oxyr i a dIgnxa
PoIX9onum vlviparum
Rumex arct Icus
Portulacaceae
Claxtonla sarmentosa
Pr I mu Iaceae
Androsace chamaejasme subsp.lehmannlana
Dodecatheon frlgldum
Trientalls europaea subsp.arctlca
Pyrolaceae
Pxro1a sp.
RanuncuI aceae
Aconitum delphln!folium
subsp.delphinlfollum
Actaea rubra
Anemone narclsslflora
Anemone parvlflora
Anemone rlchardsonil
Caltha leptosepala
Delphinium glaucum
Ranuncu Ius sp.
Thallctrum sparslflorum
Rosaceae
Drxas drummondi I
Drxas iotegrifol ie
Geum macrophxllum s~bsp.perlnclsum
Geum rossil
Potentilla fruticosa
Potentilla palustris
Rosa acicularls
Rubus arcticus
Rubus chamaemorus
Rubus idaeus var.strigosus
Jacob's ladder
Mountain sorrel
AI pi ne bl stort
Arctic dock
Spring-beauty
Rock jasmine
Northern shoot I ng star
Arctic starflower
Wintergreen
Monkshood
Baneberry
Anemone
Northern anellOne
Anemone
Mountain marsh-marigold
Larkspur
Buttercup
Few-flower meadowrue
Drummond mountaln-avens
Wh Ite mountai n avens
Avens
Ross avens
Bush cinquefoil
lola rsh f I vef Inger
Prick ley rose
Nagoon-be.rry
Cloudberry
Raspberry
APPENDIX 3.0:(Page 6)
DI coty I edoneae (Cont.)
Rosaceae (Cont.)
Rubus pedatus
Sangulsorba stipulata
Sorbus scopullna
Spiraea beauverdiana
Rublaceae
Galium boreale
Ga I lum sp.
Sa I icaceae
Populus balsamifera
Populus tremuloldes
Sal Ix
Sax I tragaceae
Parnassia palustrls subsp.neogaea
p.kotzebue I
Ri bes tr i ste
Saxifraga oppositifolia
Saxifrage tricuspidata
Scrophularlaceae
Castilleja sp.
Mlmulus guttatus
Pedlcularis sp.
Pedlcularis kanei
Pedicularis labradorlca
Veronica americana
Umbel Ii ferae
Heracleum lanatum
Va ler ianaceae
Valarlana capltata
Violaceae
V 1oj a ap 1ps I Ia subsp.repens
Viola biflora
Five-leaf bramble
5 i tka burnet
Greene mountain-ash
Beauverd spirea
Northern bedstraw
Bedstraw
Balsam poplar
Quakl ng aspen
Willow
Northern grass-of-
Parnassus
Grass-of-Parnassus
Red currant
Purple mountain
saxifrage
Three-tooth saxifrage
Indian paintbrush
Yellow monkey flower
Lousewort
Kane lousewort
Labrador lousewort
Brook I ime
Cow parsn i p
Capitate valerian
Marsh violet
Violet
r--'
APPENDIX E3E
Status,Habitat Use and Relative Abundance
of Bird Species in the Middle Susitna Basin
-
APPENDIX 3.E:STATUS,HABITAT USE AND RELATIVE ABUNDANCE
OF BIRD SPECIES IN THE MIDDLE SUSITNA BASIN
"...(Adapted from Kessel et 211.198221)
!
Status 1 Main Relative,.-Species Habitats Abundance 2
Common loon B lakes U-sp,F;FC-S
Ga vI a J.!!!!!!!!:.
Arctic loon B1 lakes U-sp,S
Gavla arctlca
Red-throated loon B1 lakes,rivers U-sp,S
Gavl a stell ata
Red-necked grebe B lakes U
Podlceps grlsegena
..-
Horned grebe B lakes U
Podiceps aurltus
Whistling swan T lakes U-sp,F-Cygnus columblanus
Trumpeter swan B lakes U-sp,F,FC-S
Cygnus buccinator-Canada goose T lakes,rivers U-sp,F
Branta canadensIs
WhIte fronted goose T lakes U-sp
Anser alblfrons
Snow goose T lakes U-sp
Chen caerulescens
Ma liard B lakes,rivers C-sp,FC-S,F
Anas platyrhynchos
Gadwall T,S lakes R-sp,S-Anas strepera
Pinta!I B lakes C-sp,Fe-5,U-F
Anas acuta-Green-wlnged teal B lakes FC-sp.S,U-F
Anas crecca carollnensls
BIue-w I nged tea I T lakes R-sp,F
Anas dlscors
AmerIcan wigeon B lakes Fe
Anas amerIcana
Northern shoveler B lakes U
Anas clypeata
Redhead T lakes U-spr--Aythya americana
Ring-necked duck T lakes R-sp,F
Aythya co II ar i s--
-
APPENDIX 3.E (Page 2)
Status'
Main Relative
Species Habitats Abundance2
Canvasback T lakes U-sp
Aythya val Jsfnerla
Greater scaup B lakes C-sP.F
Aythya mar IIa
Lesser scaup B lakes FC-S
Aythya aff InIs
Common goldeneye B lakes.rivers FC-sp.F.U-S
Bucephala clangula
Barrow's goldeneye B lakes.rivers
Bucephala Islandlca
Buff Iehead T lakes U-sP.FC-F
Bucephala albeola
Oldsquaw B lakes FC-sp.5;U-F
Clangula hyema 11 s
Har Iequ r n duck B rivers FC
Hfstrlonlcus hlstrlonlcus
White-winged scoter T lakes FC
Melanltta deglandl
Surf scoter B lakes U
Melanitta persplclllata
Black scoter B lakes FC
Melanltta ~
Common merganser B lakes.rivers U
Mergus merganser
Red-breasted merganser B lakes.rlver.s U
Mergus serrator
Goshawk B decIduous and U
AccipIter gentills mixed forest
Sharp-shinned hawk B1 con J ferous and U
Accipiter strfatus mixed forest
Red-tal led hawk B coniferous and U
Buteo jamaicensls mixed forest
Golden eagle B cl I ffs FC
Aquila chrysaetos
Bald eagie B forests.cl I ffs U
Ha IIaeetus leucocephalus
Marsh hawk 81 meadows FC-sp.F;U-S
Circus cyaneus
Osprey T lakes R-sp
Pandlon haliaetus
,~
-
-
APPENDIX 3.E (Page 3)
~
Status 1
Main Relative
""'"Species Habitats Abundance2
Gyrfalcon B,W c Ii ffs U
~rustlcolus
Peregrine fa Icon T1 clIffs 2 records (1974)
Falco peregrlnus
Merlin B1 scattered U
Falco columbarius wood land,
forest edge
American kestrel T open forest R-F
Falco sparverlus
Spruce grouse B,W con i fer lous and FC
Canachltes canadensis mixed forest-Ruffed grouse V forest R
Bonasa umbe II us
Wi Ilow ptarmigan B,W low shrub land C
.-Lagopus lagopus
Rock ptarmigan B,W -low ,dwarf C
Lagopus mutus shrub land,
block fields.-
White-tal led ptarmigan B,W high e Ievat Ion U
Lagopus leucurus dwarf shrub
tundra and
block fields
~
Sandh III crane T wet lands U
Grus canadensis
:-Semlpalmated plover B alluvial bars U
Charadrius semipalmatus
Amer Ican go Iden plover B dwarf shrub C
Pluvialis domlnica mat a nd meadow
Whlmbrel B1 dwarf shrub U
Numenlus phaeopus meadow
..-Upland sandpiper B1 dwarf shrub R
Bartramla ,Iongicauda meadow near
scattered
woodland
Greater yellowlegs B1 wet,meadows,U
Tringa melanoleuca lakes and rl ver
shore lines
~Lesser yellowlegs T,S lake and river FC-sp;R-S
Tringa flavipes shore I ines
So Iitary sandpiper B1 scattered wood-U
.-Tringa sol itaria land,forest
edge near lakes
,....
APPENDIX 3.E (Page 4)
Species
Spotted sandpiper
Actltls macularla
Wandering tattler
Heteroscelus Incanus
Turnstone
Arenaria sp.
Status'
B
(B11,T
T
Main
Habitats
alluvial bars
tundra streams
alluvial bar
ReiatlYe2Abundance
C
u
R
Northern phalarope
Phalaropus lobatus
CORmon sn I pe
Cape I I a ga I II nago
Long-billed dowitcher
Llmnodromus scolopaceus
Surfblrd
Aphrlza vlrgata
Sanderling
Ca I 1dr I s aI ba
Semlpalmated sandpiper
Ca I I dr I s pus [I I a
Least sandpIper
Calldrls mlnutl Iia
B1
B
T
B1
T
T,S
B1
wet meadows FC
with ponds
wet meadows C
lake and river U-sp
shores and bars
dwarf shrub mat R
lake and river R-F
shores and bars
lake and river U-sp,R-S
shores and bars
wet and dwarf FC
shrub meadow
Baird's sandpiper
Calldrls bairdl i
B dwarf shrub
mat
U
Pectoral sandpiper
Calidrls melanotos
Long-tailed Jaeger
Stercorarlus longlcaudus
Herr I ng gu I I
Larus argentatus
Mew gu II
Larus~
Bonaparte's gull
~phi ladelphia
T
B1
T,S
B,S
B,S
wet meadows,U
pond,lake edges
dwarf shrub FC
mat and meadow
lakes,rivers U
lakes,rivers C
lakes,rivers,U
scattered spruce
woodland
open and U
c10sed forest
Arctic tern
Sterna paradlsea
Great horned ow I
Bubo vtrglnlanus
Snowy Owl
Nycte8 scandlaca
B
81,W
T
lakes and
lakeshores
tundra
FC
R
forest edge U
deciduous and U
mixed forest
open deciduous U
and mI xed forest
openshrubland Accidental
....
APPENDIX l.E (Page 5)
Species
Hewk owl
Surn I a .!!.!.!:!.!!.
Short-eared owl
Aslo flallllllElus
Boreat owl
Aego I Ius funereus
Belted kingfisher
Mega cery I e a I cyon
Common t I I cker
Colaptes auretus
Helry woodpecker
Plcoldes vi I losus
Downy woodpecker
Plcoldes pubescens
Black-backed three-toed
woodpecker
Plcoldes arctlcus
Northern three-toed woodpecker
Plcoldes trldactylus
Eastern kingbird
Tyrannus tyrannus
Say's phoebe
Sayorn Is saya
AIder flycatcher
Empldonax alnorum
Western wood pewee
Contopus sordldulu5
QIIYe-slde~-flycetcher
Nuttallornls borealis
-Horned terk
Eremophl Ie elpestrls
Status'
81,W
T,S,(B1)
B1 W
B1
B
B,W
B1,W
B1,W
8,W
A
8
81
B1
81
B
Main
Ha~l"tats
mixed forest
open habitat
mixed forest
cutbanks,
rl vers
con I ferous
forest
coniferous
forest
upland cliff
medium and
tall shrubs
deciduous
forest
open and
scattered
forest
dwarf shrub
mat.block
field
Relatl ve
Abundance 2
u
u
R
u
R
u
u
U
R
U
C-sp,F;FC-S
VloJet-green swallow
Tachyctne"ta thalasslna
Tree swallow
Irldoprocne blcolor
Bank swa I low
Rlparla rlparla
Cliff swallow
Hlrundo pyrrhono"ta
B1
81
B
B
riparian FC
ct Iffs,rivers
rivers,lakes FC
artbanks,U
rivers
rivers,lakes U,L
APPENDIX 3.E (Page 6)
Status 1
Main Relatl ve
Species Habitats Abundance2
Gray Jay 8,W con r ferous and C
Perisoreus canadensis mixed forest
8lack-br lied magpie 5,(B?)W open tall U
Plca~shrubs,scattered
forest
Comrron raven B,W riparian and C
Corvus corax upland cliffs
Black-capped chickadee 8,W deciduous U
Parus atricapll Ius forest
Boreal chickadee B,W coniferous FC
Parus hudsonlcus and mixed
forest
Brown creeper B deciduous and U
Certhia fami Ilaris mixed forest
Di pper 8?W rivers,U
Cinclus mexlcanus streams
American robin 8 forest,medium C-sp,S;U-F
Turdus mlgratorius and ta II
shrubland
Var I ed thrush B forest,tall O-sp,S;U-F
Ixoreus naevius alder thickets
Hermit thrush B strip forested C-sp,F;U-F r-:--c:~-
Catharus guttatus slopes,ta 11-
alder thickets
Swainson's thrush B forest FC
Catharus ustulatus
Gray-cheeked thrush B scattered FC
Catharus minlmus spruce,dwarf
spruce,deciduous
forest
Wheatear B block fie I ds U
Oenanthe oenanthe
Townsend's solitaire B ell ffs U
Myadestes townsendi
Arctic warbler 8 scattered FC
Phy I loscopus borea Irs forest,
medium
shrub land
Golden-crowned kinglet T coniferous and U
Regu Ius satra pa mixed forest
RUby-crowned kinglet B coniferous C
Regulus calendula forests r"----',
.....
APPEND IX 3.E (Page 7)
-
Status 1
Main Relatl ve 2
!"""Species HabItats Abundance
Water pipit B dwarf shrub C
Anthus splnoletta mat,block
field
Bohemian waxwing B?scattered CTsp,F,U-S
Bombycl Iia garru I us forest
r-Northern shrike B scattered U
Lan I us excu bI tor forest,tall
shrubs
Orange-crowned warbler B scattered U
Vermlvora celata fores t,med i um
and tall
shrubland
Yellow warbler T,S?riparian R
Dendrolca petechia wi I lows
Yellow-rumped warbler B forest C
Oendrolca coronata
Blackpoll warbler B tall shrubs,FC
Dendrolca striata forest
Northern waterthrush B?tall shrubs FC
Se/urus noveboracensrs near water
Wi Ison's warbler B mad I urn shrubs C
Wi I son ra pus I I Ia with or without
forest overstory
Rusty blackbIrd T,S?(B?l open con I ferous U
Euphagus carol i nus forest,ta II....shrubs
Pi ne grosbeak T,S (B ?l open coni ferous U
Pin leola enucleator forest-Gray-crowned rosy fin ch B?cliffs,block U
Leucostlcte tephrocotis fields
Common redpoll B,W low shrubs,A-Carduelis flammea open wood I and
Pine siskin B?mixed forest,U
Carduel is pinus tall shrubs
,....White-winged crossbi II S,B?coni ferous FC
Loxia leucoptera forest
Savannah sparrow B low shrubs A
..-Passerculus sandwlchensls with gramlnold
ground cover
Dark-eyed junco B open and C
Junco hyema I is closed forest.....
APPEND IX 3.E (Page 8)
p-
Status 1 Main Relative
Species Habitats Abundance 2
Tree sparrO'll B low shrubs A
Splzella arborea
White-crowned sparrow B low and C
Zonotrlchia leucophrys medium shrubs
Golden-crowned sparrow B1 low shrubs,U
Zonotrichla atrlcapl I la dwarf spruce
Fox sparrow B1 medium and tall FC
~assere II a ,I IIaca shrubs with
forest overs tory
Ltncoln's sparrow B1 low and medium U
Melosplza Itncolntl shrubs near
water
Lap land longspur B dwarf shrub,A
Calcarius lapponicus meadow and mat
Smith's longspur B1 dwarf shrub.U
Calcartus plctus meadow and mat I"'"
Snow buntl ng B1 high e Ievat Ion FC
Plectrophenax n tva II s ell tts and block
fields
lB breeding conftrmed,B1 =probably breeds.(B1)=possibly breeds.
T =transient.W =winters.S =summers,A =accidental
2A =abundant,C =common,FC fairly common,U =uncommon,R =rare.
sp =sprtng,S =summer,F =fall.L =local
fT-"
-
r
-
-
-
APPENDIX E3F
Status and Relative Abundance of Bird Species
in the Lower Susitna Basin
APPENDIX 3.F:STATUS AND RELATIVE ABUNDANCE OF BIRD SPECIES OBSERVED
ON THE LOWER SUSITNA BASIN DURING GROUND SURVEYS
CONDUCTED JUNE 10 TO JUNE 20,1982
Species Status 1 Relat lve
Abundance
No.of
Individuals
Observed
Arctic loon
Gavla arctica
M o (2 seen in
May 1982)
Red-throated loon
~stellata
Red-necked grebe
Podlceps grisegena
Double-crested
cormorant
Phalacrocorax aurltus
M
6 (2 seen In
May 1982)
o (5 seen in
May 1981)
o (60 seen near
mouth of river
in May 1981 and
420 seen near
mouth of river
in May 1982)
o (2 seen in
May 1981)
<50 (89 seen r n
May 1981 and 51
seen In May 1982)
M
M
MWhIte-fronted goose
Anser a Ib i frons
Snow goose (M)
Chen caeru lescens (M)
Brant
Branta bernicula
Whistling swan
Cygnus columbianus
Canada goose
Branta canadensis
M,(PS)3 (1 seen in
May 1981 an'd 26
seen In May 1982)
-
Green-winged teal
Anas crecca
Mallard
Anas platyrhynchos
Pintai I
Anas acuta
M,(PB)
M,(PB)
M,(PB)
U
U
U
Several 2's and 3's
(42 seen in
May 1981)
6
<6
6
2
Most numerous
surface feeding
duck;seen In
pa I rs a long rna J n
river and sloughs
a Imost every day
a few IndivIduals in
aerial waterbird surveys
U
U
M,(PB)
M
M
American wigeon
Anas americana
Canvasback
Aythya valislnerla
Greater scaup
Aythya mar IIa
Harlequin duck
Hlstrionicus histrlonlcus
Surf scoter M.
Melanitta perspicl I lata
2
r
I
Common go Iden eye
Bucephala clangula
M,B U 4
APPENDIX 3.F (Page 2)
Spec I es Status 1
Common merganser M,(PS)
Mergus merganser
Red-breasted merganser M
Mergus serator
Bald eagle (M),S
Hallaeetus leucocephalus
RelatIve
Abundance
FC
FC
u
No.of
Individuals
Observed
Smal I flocks of up
to 10 seen along
the rna In river;
most numerous
ducks seen in May
and June
a felt birds along the
river;~ess common
than its congenor
17 act lve nests
seen In riparian
cottonwood stands
Sharp-shInned hawk
A~clpfter strlatus
Goshawk
Acc!pter gent!lis
Red-tailed hawk
Buteo Jamalc~nsis
American kestrel
Falco sparverlus
Merlin
Falco columbarius
Sandhill crane
Grus canadensis
(M),(PS)
eR),ePH)
(M),~PB)
eM),(PS)
(M),(PS)
M
Severa I seen
Several seen
A few seen hunting
along river
Several heard at a
distance along main
river (27 seen near
mouth of river In
May 1982)
Semlpalmated plover (M),B
Charadrlus semlpalmatus
Greater yellowlegs eM),PB
Tringa melanoleuca
So I I tary sandp I per (M),(PB)
Trlnga solltaria
Spotted sandpiper eM),S
Actltus macularia
u
u
FC
c
Nests In alluvium
along the river
Seen and heard
foraging along
river
Courtship rituals
observed a long
river
Regularly seen;5
nests seen along
shores of main
river,sloughs and
feeder streams
Whfmbrel
Numenlus phaeopus
Comron sn I pe
Capella gall Inago
M
(M),(PS)FC
Only 1 observed;
assumed to be late
northbound migrant
Winnowing snipe were
heard and/or seen
along the river
APPENDIX 3.F (Page 3r
"...
No.of
Status 1
Relat Iva Individuals
Species Abundance Observed
Northern phalarope 2
Phalaropus tobatus
Parasitic Jaeger 3
Stercorarlus parasltlcus
Bonapartets gul I (M).PB Fe Pa Irs and sma II
~phlladelphla groups seen
feeding along meln
river and Sloughs
Mew gull (M)•PB Fe
Larus~
Herring gull (M),B C 7 breeding oolonles
Larus argentatus of 20 -100 pairs
seen on alluvial
Is lands along
river between
Talkeetna and....mouth of river
Black-I egged (n (R)130;normally a
kittiwake pelagic species;
..-Rlssa tridactyla nearest breed Ing
colony at Chlslk
Island In lower
Cook Intet
~Arctic tern (M ).B FC Pal rs and small
Sterna paradlsaea groups
Great horned ow I (R),(PB)Tracks seen;signs
Bubo vlrglnlanus found In beach
sand below Be I1
ISland Ind Ieate
this owl waS
feed I ng on dead
eulachon
Short-eared owl (M)Remains of one owl
~flemmeus were found below
Bell Island
Belted kingfisher (Pa)U Pairs regularly seen
Megaceryle aleyon on feeder streams
Downy woodpecker (R),(PS)ma Ie observed In
Plcoldes pubescens riparian cotton-
wood forest
r-Hairy woodpecker (R).B Fe Seen or heard
Pfcoldes villosus regularly
Northern three-toed (R),(PS>2 seen In mixed
woodpecker .forests along
Plcoldes trldactylus lower river
Common flicker .(M),(PB)A few seen and
Colaptes auratus heard In riparian
!'"cottonwood
APPENDIX E.F (Page 4)
Species Status 1
Alder flycatcher PB
Empidonax alnorum
Tree swallow (M),B
Tachycineta bicolor
Violet-green swallow (M),(PB)
Tachycineta thalassina
Bank swallow (M),B
Rlparia riparia
CI iff swallow (M),B
Hirundo pyrrhonota
Relative
Abundance
C
FC
U
FC
LC
No.of
Individuajs
Observed
Seen regularly (4th
mos t numerous
landbird
Seen regularly;3
nests seen
Sma I I numbers seen
Some co Ion i es of
30 -50 pai rs
Seen only at
Ta I keetna where
common Iy breeds
around bu i I ding
eaves
Gray jay
Perisoreus canadensis
(R),(PB)Very feti seen or
heard
Black-bi lied magpie (R)
Pica~
Common raven
Corrus corax
Black-capped
chickadee
Parus atricapil Ius
(R ),(PB)
(M),B
U
FC
Un common bu t
widely distributed
Seen regu I ar I y r~'·
Brown creeper (M)
Certhia famll iarus
Gray-cheeked
thrush
Catharus mlnlmus
Swalnson's thrush
Catharus ustulatus
Hermit thrush
Catharus guttatus
American Robin
Turdus migrator1us
Varied thrush
Ixoreus naevlus
Gol den-crowned
kinglet
Regu Ius satrapa
(M),B
(M),(B)
(M),P8
(M),B
(M),B
(M)
C
C
u
FC
FC
Seen regularly (5th
most numerous
passer i ne on
census
Seen regularly (7th
most numerous
small landblrd)
Not recorded down-
stream from
Ta I keetna
2 nests observed
Seen regularly (10th
most common
passerine
....
....
i
....
APPENDIX 3.F (Page 5)
Species
Ruby-crowned
kinglet
Regulus calendula
Boheml an waxw i ng
Bombycilla garrulus
Northern shrike
Lanius excubitor
Orange-crow ned
warbler
Vermlvora celata
Ye I low warbl er
Dendrolca petechia
Ye I low-rumped
warbler
Dendrolca coronata
Blackpol I warbler
Dendroica striata
Northern waterthrush
Selurus noveboracensis
Wilson's warbler
WIIson Ia pus IIIa
Rusty blackbird
Euphagus carolinus
Status 1
(M),PB
(M)
(M),(PB)
(M),(PB)
(M),B
(M),B
(M),B
(M),B
(M),PB
(M),B
Relat ive
Abundance
FC
u
FC
FC
C
C
C
FC
u
No.of
Individuals
Observed
Seen regularly
Fewer than 12 seen
2
Seen regu (arly
1 nest seen;tall
shrubs
2nd most common
passer i ne seen
regu lar Iy In
mixed forest,
cottonwood and
tall shrubs
3rd most common
passerine seen
regularly In tall
riparian shrubs,
cottonwood and
mixed forest
Most numerous
passerine seen
regular Iy In
riparian cotton-
wood and mixed
cottonwood
2
(M)White-winged
crossb I II
Loxia leucoptera
Savannah sparrow (M),PB
Passerculus sandwichensis
u
u
48
Fox sparrow
Passerella Illaca
(M),B C 1 nest seen
(M),BLincoln's sparrow
Melospiza I incolni I
Golden-crowned (M),B
sparrow
Zonotrichia atricapilla
FC
u Individual was
heard Just above
Be II Is land
APPENDIX ~.F (P"age 6)
No.of
Stl!lTUS 1 Relat Lve Indlvldul!Ijs
Species Abundance Obser-ved
Whlte-cr-owned 00.B C 9th IIIOSt numer-ous
sparr-ow passer I ne seen
Zonotr-Ichla leucophrys regularly In
medium to tall
shr-ub th Ickets
a nd cottonwood
torests on smBl I
Islands
Dar-k-eyed Junco (M),8 FC
~hyemalls
COlllllon r-edpoll (M)FC
Car-duel Is tlamm8a
p--
Pine siskin (M)U A few were heard
Car-duel Is ~or seen In
cottonwoods
along river
llncludes lntormatlon on migration trom aerial surveys In May 1981 and 1982.
2()IndIcates assessments ot status or relative abundance other than those
pr-ovlded by the University ot A laska museum.
3a =breeding confirmed,pa =probably breeds,M =migrant,R =r-esldent
4R =rare,U=uncollVllOn,FC =fairly common,C =comlllOn,L.C =locally common
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APPENDIX E3G
Scientific Names of Mammal Species
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APPENDIX 3.G:
Common Name
Masked Shrew
Dusky Shrew
Northern Water Shrew
Arctic Shrew
Pygmy Shrew
Little Brown Bat
Collared Pika
Snowshoe Hare
Hoary Marmot
Arctic Ground Squirrel
Red Squirrel
Beaver
Northern Red-backed Vole
Meadow Vole
Tundra Vole
Singing Vole
Muskrat
Brown Lemming
Northern Bog Lemming
Porcupine
Be Iukha Wha Ie
Coyote
Wolf
Red Fox
Black Bear
Brown Bear
Marten
Short-tal led Weasel
Least Wease I
Mink
Wolverine
River Otter
lynx
Moose
Caribou
Dal I Sheep
SCIENTIFIC NAMES OF MAMMAL SPECIES
FOUND IN.THE PROJECT AREA
Scientific Name
Sorex clnereus
Sorex mon t Ico I us
Sorex pa I ustr Is
Sorex arctlcus
MIcrosorex ~
Myotls luclfugus
Ochotona collarls
Lepus amerlcanus
Marmota callgata
Spermophi Ius parryli
Tamiasclurus hudsonlcus
Castor canadensis
Clethrlonomys rutl Ius
MIcrotus pennsylvanicus
Microtus oeconomus
Microtus mlurus
Ondatra zlbethlca
Lemmus slbirlcus
Synaptomys borealis
Erethizon dorsa tum
Delphinapterus leucas
Canis latrans
Canls~
Vulpes fulva
Ursus amerlcanus
Ursus arctos
Martes amerIcana
Mustela erminea
Mustela nival is
Mustela vlson
Gulo .9..!!...!£.
Lutra canadensis
Lynx canadensis
Alces alces
Rangifer tarandus
Ovls~
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APPENDIX E3H
Methods Used to Determine Moose Browse Utilization
and Carrying Capacity within the Middle Susitna Basin
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APPENDIX 3.H
METHODS USED TO DETERMINE MOOSE BROWSE UTILIZATION
AND CARRYING CAPACITY WITHIN THE MIDDLE SUSlTNA BASIN
Moose habitat research was conducted in the middle basin in 1982 by the
Plant Ecology Team of the University of Alaska Agricultural Experimen-
tal Station.The objective of the moose browse study was to estimate.
the avai 1abi 1i ty of browse and herbaceous p1 ants for each vegetation
type.
Field Methods
Sites sampled were randomly selected using a grid overlay on a vegeta-
tion map of the area within about 5 miof potential dam impoundments.
However.eight sites were 10'cated mid-slope at the phenology study
sites on both north and south-facing slopes to insure that some samples
occurred in the immediate impoundment area.Sites were classified to
Level s IV and V of Viereck et a1.(l982),when possib1 e.Forty-seven
stands were examined from July through August 1982.Some habitat types
were sampled more intensively than others.based on their importance to
moose and/or 1and area occupi ed by that type.
At each samp1 e site.three parallel 50-m 1 ine transects were estab-
1 ished.approximately 10 to 20 m apart.Every 10 m along each transect
line.a plot (1 x 0.5 m)was located.Percent cover of each plant
species.including trees less than 1.13 m in height.was estimated in
each 0.5 m2 plot.All grasses.Carex.forbs.and the current annual
growth of tall shrubs were clipped in each plot.Clipped samples were
bagged.oven-dried at 60°C for 48 hours.then weighed.Kg/ha of grami-
noids.forbs.and leaves and twigs of moose browse species were calcu-
lated by multiplying the biomass (in grams)from 0.5 m2 plots by 20.
A circular plot with a 5 m radius was established every 10 m along each
transect line.This plot was divided into 4 even-sized quadrants.
Within each quadrant.the distance to the nearest stem of each browse
species represented within a quadrant was measured.The basal diameter
and average height of that stem was measured and the number of twigs.
above 50 cm (19 inches).was counted and noted as to evidence of recent
browsi ng.A twig was defi ned as a branch that had a diameter equal to
the estimated diameter at point of browsing for that species.The
average diameter at point of browsing for each species was estimated by
randomly measuring twigs that were browsed at a nLDllber of sites over
the entire study area.Percent utilization was determined by dividing
the number of browsed twigs by the total number of twigs ab<;>ve 50 cm.
At each site.25 twigs from each browse species present were also
randomly harvested at the average poi nt of browsing.These twi gs
provided an estimate of biomass removed when the shrubs had been
browsed by moose.
Carrying Capacity
A prel iminary estimate of moose carrying capacity was cal cul ated from
the browseb4omass estimates obtained in slJllmer 1982.A ~imulation
modeling approach is being developed to calculate carrying capacity and
project impacts on moose based on available energy and nitrogen,snow-
fall,and other important inputs,.and therefore,a greatly refined
estimate of carrying capacity will eventually be available.The preli-
minary estimate shown in Table £.3.92 is based on the following data
and assumptions:
1.Browse biomass estimiltes for each Level III vegetation type are
representative of all other simil ar stands throughout the middle
basin (e.g.,all open conifer forest stands have the same biomass
as those sampled).
2.The vegetation maps produced in 1980-81 accurately portray the
vegetative cover of the middle basin (vegetation is being remapped
now that low-level photography is available).
3.Moose in winter eat only the current annual growth of twigs of the
following species:Richardson willow,grayleaf willow,diamondleaf
willow,Sitka alder,and resin birch.The calculations assume that
none of the twigs are consumed in summer,and that snow does not
make any twigs unavailable.Both of these assumptions are in fact
false;however,the analysis is also biased in the other direction
because moose can consume more than the current annual growth of
twigs,eat other browse species in winter,and consume some leaves
and forbs available in winter.
4.A moose in winter requires 5.0 kg dry weight of browse per day
(Gasaway and Coady 1974).This value takes into account the
composition and digestibil ity of the diets of moose in interior
Al aska.
5.Areas mapped as closed conifer forest,closed birch forest,closed
mixed forest,tall shrub (mostly alder),and tundra,contain no
moose browse avail able to moose in winter.Except for tundra and
tall shrub types,these types cover only a small proportion of the
middle basin,and closed forest stands support low browse biomass.
Little,if any browse is available to moose in tundra areas and
tall shrubs are mostly al der,which is not a preferred browse
species.
6.The number of moose days the areas can support is calculated for
the Watana impoundment and adjacent vill age and borrow sites and
for the entire watershed upst ream of Gol d Creek.The number of
winter residents these areas can support is calculated assuming
that winter 1 asts for 180 days and food requi rements a re the same
throughout that period,and that moose do not move into or out of
the study areas.
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APPENDIX E3I
Explanation and Justification of Artificial Nest Mitigation
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APPENDIX 3.1
EXPLANATION AND JUSTIF ICATION OF ARTIFIC IAL NEST MITIGATION
Th~concept of modifying cliff-nesting and tree-nesting habitat to
provide raptors new nesting locations and nest sites appears to offer
an effective and feasible means of compensating for losses of nesting
habitat incurred in the upper Susitna River basin as a result of con-
struction and operation of the Susitna Hydroelectric Project.A major
advantage of this type of compensation is that it allows actual mitiga-
tion of losses in the same area where they were incurred,rather than
on distant 1 ands or by some form of out-of-ki nd compensation.The con-
cept relies on the fact that raptors are one of the few groups of birds
that are limited by availability of nesting locations and nest sites in
most regions)rather than food (see Newton 1979).Many methods and
techniques have proven successful,and additional techniques and
methods are bei ng developed and tested (e.g.01 endorff et al.1980).
Some successful applications and experiments involving several raptor
species are given below.
1.Nest sites ("po t-hole ll type)have been successfully provided
for prairie falcons (Eo Mexicanus)in cliffs that lacked
natural cavities in Alberta (Fyfe and Armbruster 1977).
Originally,some holes were blasted out of the rock,but it
became more effective to locate soft spots in the sandstone
and dig them by hand.The program has provided about 200 new
cavities for nesting prairie falcons,about 25 percent of
whi ch have been used successfully)and has increased the
number of prairie falcons in several Alberta river drainages.
2.A ledge was excavated in December 1979 on a cliff in Califor-
nia that was rated as a potential peregrine falcon nesting
location,but had no history of previous use.Four months
later,early in the 1980 nesting season,a female peregrine
occupied it.She laid eggs on the new ledge and was observed
incubating them (see Olendorff et al.1980).
3.Because nest sites at some peregrine nesting cliffs in the
Massif Central of Europe were accessible to predators (gen-
ets),a new artificial,but natural appearing,ledge was con-
structed in a rock face near the top of one of the nesti ng
locations.It was readily accepted by a pair of peregrines
(Cugnasse 1980).
4.The nesting ledge fell off an abandoned peregrine falcon nest-
ing cliff in California.A steel and lightweight metal ledge
was fabricated,artistically modified to look relatively natu-
ral,and installed on the rock face in four days time.The
following year a pair of prairie falcons accepted the ledge
and successfully fledged young from it (Boyce et al.1980).
5.A golden eagle tree-nest was blown down.The nesting loca-
tion was not occupied by eagles the following year and later
that summer an artificial nest was built.Golden eagles
nested at it the next year (Craig and Anderson in Call 1979).
6.A nest site designed for gyrfalcons was constructed on a cliff
in northern Europe.It was used by gyrfalcons the following
year (see 01endorff et a1.1980).
7.A c1 iff used by gyrfal cons was found in 1968 on the Seward
Peni nsu1 a,A1 aska.The c1 iff had only one useab1 e 1 edge on
it,although an excellent potential pot-hole site was also
present.The pot-hole site was unuseable because the floor
lacked detritus and soil for scraping in,and it also sloped
steeply to the rear of the cavity.Two years later (1970)the
original ledge had become unstable and was in danger of fall-
ing off the cliff.At the completion of the 1970 breeding
season,material (sand,dirt and fine gravel)was placed in
the pot-hole cavity to level the floor.A rim was constructed
of wi red-together sticks and in turn wi red to the rock (the
rim simulated the remains of a rough-legged hawk nest,often
used by gyrfalcons).The falcons scraped in the new site the
following year (1974),but still used the old,unstable ledge
(D.G.Roseneau and W.Walker II,unpubl.data).In later
years the ori gi na1 1edge became very del api dated and was not
used by the gyrfalcons,but the modified site was (W.R.Tilton
pers.comm.).
8.A golden eagle nest in a tree in Wyoming was located on lands
that were to be strip-mined for coal.Through a series of
manipulations involving first providing and then destroying
several artificial platforms and nests,moving a nestling
after it was capable of thermoregu1 at ion,and movi ng a nest
constructed by the eagles,the nesting pair was successfully
relocated over the course of two breeding seasons to a new
nesting location outside of the coal development area and 2.5
km from the original nesting location (Postovit et al.1982).
9.An active bald eagle nest was blown down.It was reconstruc-
ted and the two nestl i ngs successfully fl edged from it (Dun-
stan and Borth 1970).
10.In two separate attempts several nest boxes were pl aced out
specifically for'boreal owls near Fairbanks,Alaska.In both
cases several pairs of ~oreal owls readily accepted them,and
in one instance a pair of hawk owls also used one of the boxes
(D.G.Roseneau and W.R.Tilton pers.comm.).
In several cases attempts to provide a variety of artificial
structures have not worked for some species.However,in
virtually all such cases,no attempt was made to provide natural
-
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,-
appearing nesting locations and natural appearig nesting sites or
nests.Other failures have also clearly involved elements of
design and choice of locations.The failure of an attempt to
provide nest sites for peregrines and gyrfalcons at Sagwon Bluffs,
Alaska (see Olendorff et al.1980),is more readily explained by
elements of design,an abundance of nearly natural nest sites
rel ative to the abundance of peregrines and gyrfal cons at that
particular Arctic Slope location,and other factors rather than by
a failure of the technique.
In several instances,successful experiments and applications have
involved only one or two pairs of some raptor species.At pre-
sent,1 imited numbers of experiments and appl ications are more a
result of lack of opportunity and support than a lack of suffici-
ent knowl edge,methods and techniques.Successful app 1i cat ions
and experiments involving many raptor species clearly suggest that
chances of success of such compensatory measures in the Sus itna
Ri ver drai nage are hi gh for the speci es i nvo 1ved,especi ally if
proper planning,appropriate design,and expertise are employed.
Chances of success and ultimate overall effectiveness can be in-
creased further by modifying a larger number of a variety of
currently unused potential nesting locations than are lost,in-
cluding those remaining along the impoundment edge above maximum
reservoir level,those in the nearby vicinity of the project,and
those that may occur in other more distant areas of the middle and
upper Susitna River basins.This would allow pairs of raptors a
greater variety of choices.Only appropriate numbers of pairs of
each species have accepted and established themselves at the arti-
ficially modified locations.Excess locations can be remodified
to prevent their use,and thereby achieve a balanced state.
Methods and techniques u'sed to provide compensatory raptor nesting
locations and nest sites will be individually tailored to each
species and may vary slightly as each particular situation dic-
tates.Basic methods employed will center around modifying micro-
relief of existing but currently unuseable cliffs near the project
areas and in some outlying areas of the middle and upper basins,
and providing natural-appearing artificial nests where appropriate
(cliff-nesters,especially golden eagles);modifying selected
tree-cover and supplying natural appearing artificial nests where
appropriate (tree-nesters,especially bald eagles);and providing
both natural appearing and less modified nesting boxes in appro-
priate habitat (cavity nesters,including boreal owls,hawk owls
and kestrels).Artificial platforms with artificial but natural
appearing stick nests that can be installed on selected transmis-
sion towers will also be experimented with (especially for golden
eagl es).
Compensatory measures will take into account such factors as slope,
aspect,height,overlook,distance to alternates,and overall dis-
tribution of n~sting locations,accessability to predators,drain-
age,sun shadow,and vegetation types and size used to construct
nests as appl icabl e to each species.All compensatory measures
will be monitored and modifications made as necessary.Detailed
accounts of methods,techniques and results will be kept to ensure
maximum scientific value for further evaluation and use.
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APPENDIX E3J
Personal Communications
....
APPENDI X 3.J
PERSONAL COMMUNICATIONS
M.Amaral.1982.U.S.Fish and Wildlife Service •
R.Archibald.1982.Yukon Game Branch,Whitehorse
W.Ba 11 ard.1982.Al aska Department of Fi sh and Game
F.Banfield.1982.Rangifer Associates,St.Catherines,Ontario
R.Bonar.1982.British Columbia Hydro Revelstoke,B.C.
S.Buskirk.1982.Institute of Arctic Biology,University of Alaska
D.Calkins.1982.Alaska Department of Fish and Game
K.Chil d.1982.British Columbia Wildlife Branch,Prince George,
B.C.
B.Cooper.1982.University of Alaska Museum
L.Duncan.1982.Acres American Incorporated
D.G"j bson.1982.Uni versi ty of Al aska Museum
P.Gi pson.1982.Al aska Cooperati ve Wil dlife Research Unit,
University of Alaska
J.Green.1982.LGL Envi ronmental Research Associ ates,Ltd.,
Edmonton,Alberta
F.Harper.1982.British Columbia Wildlife Branch,Fort St.John,
B.C.
D.Herter.1982.LGL Alaska Environmental Research Associates,Ltd.,
Fai rbanks
To Hobgood.1982.Institute of Arctic Biology,University of Alaska
(cited in Kessel et ale 1982a).
J.Ireland.1982.Resident of Murder Lake (cited in Kessel et al.
1982a).
B.Kessel.1982 and 1983.Universi~y of Al aska Museum
J.King.1982.U.S.Fish and Wildlife Service
H.Larsen.1981.Trapper and Alaska Railroad Agent,Gold Creek (cited
in Gipson et al.1982)
T.Lavender.1982.Acres Consulting Services,Ltd.,Niagara Falls,
Ontari 0
S.MacDonald.1982.University of Alaska Museum
A.Magoun.1982.Institute of Arctic Biology,University of Alaska
J.McBeath.1982.University of Alaska Agricultural Experiment
Station,Palmer (cited in Kessel et ale 1982a).
J.McKendrick.1982.University of Alaska Agricultural Experiment
Stat ion,Palmer
S.Miller.1982.Alaska Department of Fish and Game
R.Modafferi.1982.Alaska Department of Fish and Game
R.Movald.1982.British Columbia Hydro,Hudson Hope,B.C.
E.Powell.1982.Trapper and Lodge Manager,Stephan Lake Lodge
R.Peterson.1982.University of Alaska
K.Pitcher.1982.Alaska Department of Fish and Game
E.Powell.1982.(cited in Kessel et ale 1982a)
R.Rausch.1982.Juneau (cited in Kessel et ale 1982a)
W.Regelin.1982.Alaska Department of Fish and Game
D.Roseneau.1982.LGL Alaska Environemntal Research Associates,
Ltd.,Fai rbanks
R.Roullier.1981.Gold Creek Resident (cited in Gipson et ale 1982)
A.,Springer.1982.Falco Enterprises,Fairbanks
N.Thomas.1982.Conservation Officer,MacKenzie,B.C.
R.Tobey.1982.Alaska Department of Fish and Game
D.Wier.1982.Raptor Biologist
D.Wilson.1981.Fur Dealer,Copper Center (cited in Gipson et ale
1982)
J.Woolington.1981.Institute of Arctic Biology,University of
Alaska
M.Wrabetz and R.Ward.1982.U.S.Bureau of Land Management.
Anchorage,Alaska
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GLOSSARY
Accipiter -a member of the family accipitridae,which includes
kites,hawks,and eagles
Adipose fin -a small,thick,posterior dorsal fin containing much
fatty matter,typi cal of salmoni d fi sh
Albedo -the percentage of light reflected from a surface
Alevins -newly hatched salmon still attached to the yolk sac
Alpine tundra -plant communities which occur above timberline.
Vegetation is low and matlike and includes a high proportion of
grasses and sedges
Anadromous -an organism that ascends freshwater rivers from the
ocean in order to breed
Aspect -appearance,composition,or inferred environmental implica-
tion of a rock body.Also a particylar compass direction
Aufei s -a sheet of i ce formed on a ri ver p1ai n when shoa 1s freeze or
are dammed so that water spreads over the floodpl ai n and freezes
Bankfill stage -that river stage which fills the river banks up to
the shoreli ne vegetati on,typi cal of mean annual flood
Browse -leaves,shoots,and twi gs of shrubs and trees uti li led as
food
Calcareous -growing on limestone or soils high in lime
Calciphilic -having a tendency to grow in soi ls rich in calcium or
li mestone
Closed forest -forested areas in which the overstory prevents most
of the sunlight from reaching the ground
Coniferous -plants which are cone bearing and nondeciduous,such as
pi nes and spruce
Coregonid -member of the whitefish fami ly Coregonidae,related to
the salmonids,has a rayless adipose fin
Decadent -decayi ng or decli ni ng in vi gor
Deci duous -ref erri ng top 1ant s whi ch shed t hei r 1e aves at a c ert ai n
season each year
Ecotone -the area where two or more plant communities meet and blend
together
Escapement -the process by which adult anadromous fish migrate from
the ocean to their freshwater spawning sites
Floristics -study of the species composition of vegetation
Frazi1 ice -ice of small plate-like crystals suspended in the flow
Gi 11netti n9 -a method of capturi ng fi sh by hangi ng nets in whi ch the
gi lls of the fish become entangled
Glacial flour -silt and clay sized generally nonplastit particles
derived from glacial grinding
G1ey - a dense clay layer often present under waterlogged soi ls
Ground truthing -the process of conducting onsite field studies to
determine if identification of vegetation cover types from aeri a1
photographs is correct
Herb -plant such as grasses which have no persistent parts above
ground,as distinct from shrubs and trees
Herbaceous - a plant having the characteristics of an herb
Lentic system -relating to sti 11 water such as lakes and ponds
Lotic system -relating to moving water such as rivers and creeks
Mainstem -the major portion of a river into which tributaries enter
Mesi c -referri ng to si te condi ti ons that are i ntermedi ate between
wet and dry
Micro-relief -very slight changes in elevation
Mi 111 n9 area -an area ina ri ver or stream where anadromous fi sh
hold or rest prior to continuing their upstream movements
Mi xed forest -area whi ch cont ai ns both coniferous and deci duous
trees
Mosaic - a composite resulting from the joining of separate and
di fferent parts
Muste1ids -member of the fami ly mustelidae which includes weasels,
mink,skunk,otter,fish and marten
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I
Open forest -forested areas in which the spacing of trees and
closure of the canopy is such that the majority of the sunlight
reaches the ground
Parturient -bringing forth or about to bring forth young
Peri-glacial -adjacent to the margins of a glacier
Redd -spawning ground or nest of fish
Seral growth -the process by which any stage of a plant community
which is transitory will eventually reach a climax condition
Smolt - a young salmon approximately two years old
Sub-nivean -underneath the snow
Successional stands -any stage of a plant community which is transi-
tory and wi 11 eventually lead to a climax condition
Taxa -plural of taxon
Taxon - a separate and di sti nct group ina formal system of c1assi fi-
cati on
Thermokarst -sett 1i ng or c avi ng in of the ground due to melti ng of
ground ice
Ungulates -hoofed mammals such as deer,caribou,and moose
Vascular -containing vessels which conduct fluid
Xerosere -a plant successional stage originating on a dry si te
.~.---~------------~-I.~..'-
Susltna
Hydroelectric ~\.
Project ~
1
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110.
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'<:-.)"'-""
"<•GB
705
A4
8966
1982
DATE =r-'--
ISSUED TO =
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