HomeMy WebLinkAboutAPA150TNA HYDROELECTRIC PROJEC
FERC LICENSE APPLICATION
PROJECT NO.7114-000
As accepted by FERC,July,27,19~3
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BEFORE THE
FEDERAL ENERGY REGULATORY COMMISSION
APPLICATION FOR LICENSE FOR MAJOR PRO"IECT
SUSITNA HYDROELECTRIC PROJECT
VOLUME 9
EXHIBIT E
Chapter 10
FEBRUARY 1983
Prepared by:
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1....--__ALAS KA POWER AUTHOR ITY __----'
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SUSITNA HYDROELECTRIC PROJECT
VOLUME 9
EXHIBIT E CHAPTER 10
ALTERNATIVE LOCATIONS,DESIGNS,AND ENERGY SOURCES
1 -ALTERNATIVE HYDROELECTRIC SITES
TABLE OF CONTENTS
2 -ALTERNATIVE FACILITY DESIGNS .
2.1 -t.Jatana Facility Design Alternatives .
2.1.1 -Diversion/Emergency Release Facilities .
2.1.2 -Main Spillway .
2.1.3 -Power Intake and Water Passages .
2.1.4 -Outlet Facilities .
2.2 -Devil Canyon Facility Design Alternatives .~.
2.2.1 -Ins tal 1ed Cap ac it Y •...••...•.••••..•.•••.•.•...•.
2.2.2 -Spillway Capacity ..
2.2.3 -Power Intake and Water Passages .
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1.1 -
1.2
1.3 -
Non-Susitna Hydroelectric Alternatives .
1.1.1 -Screening of Candidate Sites .
1.1.2 -Basis of Evaluation .
1.1.3 -Rank Weighting and Scoring .
1.1.4 -Eval uat ion Results .
1.1.5 -Plan Formulation and Evaluation .
Environmental Assessment of Selected
Alternative Sites .
1.2.1 -Description of Chakachamna Site .
1.2.2 -Description of Snow Site .
1.2.3 -Description of Keetna Site .
1.2.4 -Environmental Impacts of Selected
Alternatives .
Middle Susitna Basin Hydroelectric Alternatives ..
1.3.1 -Damsite Selection .
1.3.2 -Site Screening .
1.3.3 ~Formulation of Susitna Basin
Development Pl ans ..
1.3.4 -Plan Evaluation Process .
1.3.5 -Comparison of Plans .
1.3.6 -Results of Evaluation Process .
1.3.7 -Devil Canyon Dam Versus Tunnel .
1.3.8 -Watana-Devil Canyon Versus
High Devi 1 Canyon-Vee .
1.3.9 -Preferred Susitna Basin Development Plan .
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TABLE OF CONTENTS
2.3 -Access Alternatives .
2.3.1 -Objectives .
2.3.2 -CDrridor Identification and Selection .
2.3.3 -Development of Plans '".
2.3.4 -Evaluation of Plans .
2.3.5 -Description of Most Responsive
Ac c es s Plan s .
2.3.6 -Comparison of Selected Alternative Plans .
2.3.7 -Summary of Final Selection of Plans , .
2.3.8 -Modifications to Recommended Access Plan .
2.4 -Transmission Alternatives .
2.4.1 -Corridor Selection Methodology ..............•..
2.4.2 -Environmental Selection Criteria .
2.4.3 -Identification of Corridors ,.
2.4.4 -Environmental Screening Criteria .
2.4.5 -Environmental Screening Methodology .
2.4.6 -Screening Results .
2.4.7 -Proposed Corri dor .
2.4.8 Route Selection Methodology , .
2.4.9 -Environmental Route Selection Criteria .
2.4.10 -Evaluation Following Access Road Decision .
2.4.11 -Conclusions .
2.5 -Borrow Site Alternatives .
2.5.1 -Watana Borrow Sites .
2.5.2 -Devil Canyon Borrow Sites ,
3 -ALTERNATIVE OPERATING SCENARIOS .
3.1 -Project Operation and Flow Selection .
3.1.1 Simulation Model and Selection Process .
3.1.2 -Pre-project Flows ..
3.1.3 -Project Flows .
3.1.4 -Energy Production and Net Benefits .
3.2 -Instream Flow and Fishery Impacts on Flow Selection .
3.2.1 -Susitna River Fishery Impacts .,.
3.2.2 -Tributary Fishery Impacts '".
J.3 -Other Instream Flow Considerations .
3.3.1 -Downstream Water Rights .
3.3.2 -Navigation and Transportation .
3.3.3 -Recreation '.
3.3.4 -Riparian Vegetation and Wildlife Habitat .
3.3.5 -Water Quality .
3.3.6 -Freshwater Recruitment at Cook Inlet .
3.4 Operational Flow Scenario Selection .
3.5 Maximum Drawdown Selection .
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TABLE OF CONTENTS
4 -ALTERNATIVE ELECTRICAL ENERGY SOURCES .
4.1 -Coal-Fired Generation Alternative .
4.1.1 -Existing Environmental Condition .
4.1.2 -Environmental Impacts .
4.2 -Tidal Power Alternatives ..
4.2.1 -Preferred Tidal Schemes '"
4.2.2 -Environmental Considerations .
4.2.3 -Effects on Biological Resources .
4.2.4 -Other Effects .
4.2.5 -Socioeconomic Assessment .
4.2.6 -Impact on Adjacent Land Uses .
4.2.7 -Materials Origin Supply Study .
4.2.8 -Labor Supply and Limitations .
4.2.9 -Community Impact .
4.2.10 -Impacts of a Causeway .
4.3 -Thermal Alternatives Other Than Coal .
4.3.1 -Natural Gas .
4.3•2 -Oi 1 •••.....•.•.•...........•.••...•....•.•...•.•
4.3.3 -Diesel .
4.3.4 -Environmental Considerations
of Non-coal Thermal Sources .
4.4 -Nuclear Steam Electric Generation .
4.4.1 -Siting and Fuel Requirements .
4.4.2 ~Environmental Considerations '".
4.4.3 -Potential Application in the Railbelt Region .
4.5 -Biomass .
4.5.1 -Siting and Fuel Requirements .
4.5.2 -Environmental Considerations .
4.5.3 -Potential Application in the Railbelt Region .
4.6 -Geothermal .
4.6.1 -Siting Requirements ,.
4.6.2 -Environmental Impacts .
4.6.3 -Potential Application in the Railbelt Region .
4.7 -Wind .
4.7.1 -Large Wi nd Systems .
4.7.2 -Small Wind Systems .
4.8 ...;So 1ar .
4.8.1 -Sit-ing Requirements .
4.8.2 -Environmental Considerations .
4.8.3 -Potential Application to the Railbelt Region .
5 -ENVIRONMENTAL CONSEQUENCES OF LICENSE DENIAL
REFERENCES
LIST OF TABLES
LIST OF FIGURES
GLOSSARY
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LIST OF TABLES
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Table
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E.10.23
E.10.24
Title
Summary of Results of Screening Process
Sites Eliminated in Second Iteration
Evaluation Criteria
Sensitivity Scaling
Sensitivity Scaling of Evaluation Criteria
Site Evaluations
Site Evaluation Matrix
Criteria Weight Adjustments
Site Capacity Groups
Ranking Results
Shortlisted Sites
Alternative Hydro Development Plans
Operating and Economic Parameters for
Selected Hydroelectric Plants
Potential Hydroelectric Development
Results of Screening Model
Environmental Evaluation of Devil Canyon Dam
and Tunnel Scheme •
Social Evaluation of Susitna Basin
Development Schemes/Plans
Overall Evaluation of Tunnel Scheme and
Devil Canyon Dam Scheme
Environmental Evaluation of Watana/Devil
Canyon and High Devil Canyon/Vee Development Plans
Overall Evaluation of the High Devil Canyon/Vee and
Watana/Devil Canyon Dam Plans
Environmental Constraints -Southern Study Area
Environmental Constraints -Central Study Area
Environmental Constraints -Northern Study Area
Summary of Screening Results
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LIST OF TABLES
Table
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Title
Pre-project Flows at Watana
Pre-project Flows at Devil Canyon
Pre-project Flows at Gold Creek
Monthly Flow Requirements at Gold Creek
Alaskan Gas Fields
Alaskan Oil Fields
Sulfur Dioxide Emissions for Various Technologies
Particulate Matter Emissions for
Various Technologies
Nitrogen Oxides Emissions For Various Technologies
National Ambient Air Quality Standards and
Prevention of Significant Deterioration Increments for
Selected Air Pollutants
Water Quality Data for Selected Alaskan Rivers
Fuel Availability for Wood and Municipal Wastes
Approximate Required Temperature of
Geothermal Fluids For Various Applications
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LIST OF FIGURES
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Figure
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E.10.14
E.10.15
Title
Susitna Basin Plan Formulation and Selection Process
Selected Alternative Hydroelectric Sites
Generat ion Scenari 0 Incorporating Thermal and Alternati ve Hydropower
Developments -Medium Load Forecast -
Formulation of Plans Incorporating Non-Susitna Hydro Generation
Damsites Proposed by Others
Alternative Access Corridors
Access Plan 13 (North)
Access Plan 16 (South)
Access Plan 18 (Proposed)
Alternative Transmission Line Corridors -Southern Study Area
Alternative Transmission Line Corridors -Central Study Area
Alternative Transmission Line Corridors -Northern Study Area
Watana Borrow Si te Map
Devil Canyon Index Map
Potential Tidal Power Sites
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10 -ALTERNATIVE LOCATIONS,DESIGNS,AND ENERGY SOURCES
This chapter presents the results of assessments of the environmental
impacts of alternati ves to the proposed Susitna Hydroelectric PrQject.
Included in this assessment is a consideration of alternative hydro-
electric generating sites outside the upper Susitna Basin and alterna-
tive sites within the basin.The alternatives considered in formulat-
ing the proposed project are discussed,including transmission line and
access route.Alternative operating scenarios are discussed below and
in Sections 2 and 3.Finally,an environmental assessment of alterna-
tive methods of generation (coal-fired hydroelectric,gas,oil and
tidal and other alternatives)is presented in terms of differential
environmental impact.
1 -ALTERNATIVE HYDROELECTRIC SITES
1.1 -Non-Susitna Hydroelectric Alternatives
The analysis of alternative sites for non-Susitna hydropower
developnent followed the plan formulation and selection method-
ology discussed in Exhibit B•
Step 1 in the plan formulation and selection process was to
define the overall objective of the exercise.For Step 2 of the
process,all feasible sites were identified for inclusion in the
subsequent screening process.The screening process (Step 3)
eliminated those sites that did not meet the screening criteria
and yielded candidates which could be refined and included in the
formulation of Rail belt generation plans (Step 4).
Details of each of the above planning steps are given below and
presented in Figure E.10.1.The objective of the process was to
determine the optimum Railbelt generation plan which incorporates
the non-Susitna hydroelectric alternatives.
1.1.1 -Screening of Candidate Sites
As discussed in Exhibit B,numerous studies of hydroelectric
potential in Alaska have been undertaken.A significant amount
of the identified potential is located in the Railbelt region.
Review of the studies,and in particular the various published
inventories of potential sites,identified a total of 91 poten-
tial sites (Table E.10.1).All of these sites are technically
feasible and,under Step 2 of the planning process,were
identified for inclusion in the subsequent screening exercise.
The screening process applied to these sites for this analysis
required the application of four iterations with progressively
more stringent criteria.
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1.1 -Non-Susitna Hydroelectric Alternatives
(a)First Iteration
The fi rst screen or iteration determi ned whi ch sites were
not economically viable and rejected these sites.The
standard for economic viability in this iteration was
defi ned as energy product i on cost 1ess than 50 mi 11 s per
kWh.based on economic parameters.This value for energy
product i on cost was consi de red to be a reasonable upper
limit consistent with Susitna Basin alternatives for this
phase of the selection process.
As a result of this screen.26 sites were eliminated from
the planning process (Table E.10.1).The remaining 65 sites
were subj ected to a second iterat i on of screeni ng whi ch
included additional criteria on environmental accept-
ability.
(b)Second Iteration
The inclusion of environmental criteria into the planning
process required a significant data survey to obtain inform-
ation on the location of existing and published sources of
environmental data.A detailed review of these data and the
sources used is presented in (Acres 1981).
The basic data collected identified two levels of detail of
envi ronmental screeni ng.The purpose of the fi rst 1evel of
screening was to el iminate those sites which were 1east
acceptable from an environmental standpoint.Rejection of
sites occurred if:
-They would cause significant impacts within the boundaries
of an existing National Park.Wild and Scenic River.
National Wilderness Area.or a proclaimed National Monu-
ment area;or
-They were located on a river in which:
•Anadromous fish are known to exist;
•The annual passage of fish at the site exceeds 50,000;
and
•Upst ream from the site.a canfl uence with a t ri butary
occurs in which a major spawning or fishing area is
located.
The definition of the above exclusion criteria was made
only after a review of the possible impacts of hydropower
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1.1 -Non-Susitna Hydroelectric Alternatives
development on the natural environment and the effects of
land issues on particular site development.
Of the 65 sites remaining after the preliminary economic
screening,20 sites were eliminated 'on the basis of the
re'quirements set for the second screen.These sites
appear in Table E.10.1,and the reason for their rejec-
tion in Table E.10.2.The location of the remaining 45
sites appears in Figure E.10.2.
(c)Th i rd Iterat ion
The reduction in the number of sites to 46 allowed a reason-
able reassessment of the capital and energy production costs
for each of the remai ni ng sites to be made.Adjustments
were made to take into'account transmission line costs
necessary to 1 ink each site to the proposed Anchorage-
Fairbanksintertie.This iteration resulted in the rejec-
tion of 18 sites based on judgmental elimination of the more
obvious uneconomic or less environmentally acceptable sites
(Table L10.1).The remaining 28 sites were subjected to a
fourth iteration which entailed a more detailed numerical
environmental assessment.
(d)Fourth Iteration
To facilitate analysis,the remaining 28 sites were categor-
ized into sizes as follows:
-Less than 25 MW:
-25 MW to 100 MW:
-Greater than 100 MW:
5 sites;
15 sites;and
8 sites.
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The fourth and final screen was performed using a detailed
.numerical envi ronmental assessment which considered ei ght
criteria chosen to represent the sensitivity.of the natural
and human environments at each of the sites.
The eight evaluation criteria are listed in Table E.10.3.
For each of the evaluation criteria,a system of sensitivity
scaling was used to rate the relative sensitivity of each
site.A letter (A,B,t or D)was assigned to each site for
each of the eight criteria to represent this sensitivity.
The scale rating system is defined in Table E.10.4 •
Each evaluation criterion has a definitive significance to
the Alaskan environment and degree of sensitivity to impact
(Acres 1981,Appendix C2).A summary of the evaluatio~and
comparison of each site on the basis of these criterla is
presented in the following paragraphs.
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1.1 -Non-Susitna Hydroelectric Alternatives
1.1.2 -Basis of Evaluation
The criteria were initially weighted in accordance with their
relative significance in comparisons.The first four criteria--
big game,agricultural potential,birds,and anadromous
fisheries--were chosen to represent the most significant features
of the natural envi ronment.These resources requi re protecti on
and careful management because of thei r position in the Al askan
environment,their roles in the existing patterns of life of the
state residents,and thei r importance in the future growth and
economic independence of the state.They were viewed as more
important than the following four criteria because of their quan-
tifiable and significant position in the lives of the Alaskan
peopl e.
The remaining four criteria--wilderness;cultural,recreation and
scientific features;restricted land use;and access--were chosen
to represent the institutional factors to be considered in deter-
mining any future 1and use.These are special features which
have been identified or protected by yovernmental laws or pro-
grams and may have varying degrees of protected status,or the
criteria represent existing land status which may be subject to
change by the potential developments.
Data relating to each of these criteria were compiled separately
and recorded for each site,forming a data-base matrix.Then,
based on these data,a system of sensitivity scaling was devel-
oped to represent the relative sensitivity of each environmental
resource (by criterion)at each site.A detailed explanation of
the scale rating may be found in Table E.10.5.
The scale ratings for the criteria at each site were recorded in
the evaluation matrix.Site evaluations of the 28 sites under
consideration are given in Table E.10.6.Preliminary data
regarding technical factors were also recorded for each potential
development.Parameters included installed capacity,development
type (dam or diversion),dam height,and new land flooded by
impoundment.The complete evaluation matrix may be found in
Table E.10.7.
In this manner,the environmental data ",rare reduced to a form
from which a relative comparison of sites could be made.The
comparison was carried out by means of a ranking process.
1.1.3 -Rank Weighting and Scoring
For the purpose of evaluating the environmental criteria,the
following relative weights were assigned to the criteria.A
higher value indicates greater importance or sensitivity than a
lower val ue.
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.....Big Game
Agricultural Potential
Bi rds
Anadromous Fisheries
Wilderness Values
Cultural Values
Land Use
Access
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7
8
10
4
4
5
4
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The criteria weights for the first four criteria were then ad-
justed down,depending on related technical factors of the devel-
opment scheme.These technical factors were dam height and area
of land flooded.
All the sites were ranked in terms of their dam heights which
were assumed to be the factor having the greatest impact on
anadromous fisheries.Thus,as the height of the dam increases,
so does the value,since the impact would be greater.
Sites were also ranked in terms of their new reservoir area,or
the amount of new land flooded,which was considered to be the
one factor with greatest impact on agriculture,bird habitat,and
bi g game habitat.The same adjustments were made for the bi g
game,agricultural potentials,and bird habitat weights based on
this flooded area impact (see Table E.10.8).As the area flooded
increases,so does the rating,since impacts would likely be
greater.
The scale indicators were also given a weighted value as follows:
B 5
C ::;3
D ::;1
To compute the ranking score,the scale weights were multiplied
by the adjusted criteria weights for each criteria and the re-
sulting products were added.
Two scores were then computed.The total score is the sum of all
eight criteria,previously multiplied by the respective scale
weights.The partial score is the sum of the first four criteria
only,which gives an indication of the relative importance of the
existing natural resources in comparison to the total score.
1.1.4 -Evaluation Results
The evaluation of sites commenced by fist dividing the sites
into three groups in terms of their capacity.
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1.1 -Non-Susitna Hydroelectric Alternatives
Based on the economics,the best sites were chosen and environ-
mentally evaluated as described above.Table E.10.9 lists the
number of sites eval uated in each of the capacity groups in as-
cending order according to thei r total scores for each of the
groups.The partial score was also compared.The sites were
then grouped as better,acceptable,questionable,or unaccept-
able,based on the scores.
The parti al and total scores for each of the sites,grouped ac-
cording to capacity,appear in Table E.10.10.
Sixteen sites were chosen for further consideration.Three con-
straints were used to identify these 16 sites.First,the most
economical sites which had passed the environmental screening
were chosen.Second,sites with a very good environmental impact
rating which had passed the economic screening were chosen.And
finally,a representative number of sites in each capacity group
were chosen (Table E.10.11).
From the 1 ist of 16 sites,10 were selected for detailed develop-
ment and cost estimates required as input to the generation plan-
ning.The ten sites chosen are underlined in Table E.10.1.
Further discussion of the basis for selection of these 10 sites
is presented in (Acres 1981,Appendix C2).
1.1.5 -Plan Formulation and Evaluation
Steps 4 and 5 in the planning process consisted of the formula-
tion of the preferred sites identified in Step 3 into Railbelt
generation scenarios.To adequately formulate these scenarios,
the engi neeri ng.energy,and envoi ronmenta 1 aspects of the ten
short-listed sites were further refined (Step 4).
This resulted in formulation of the ten sites into five develop-
ment plans incorporating various combinations of these sites as
input to the Step 5 evaluations.The five develoJlT1ent plans are
given in Table E.10.12.
The essential objective of Step 5 was established as the deriva-
tion of the optimum plan for the future Railbelt generation,
incorporating non-Susitna hydro generation as well as required
thermal generation.The methodology used in the evaluation of
alternative generation scenarios for the Railbelt is discussed in
detail in (Acres 1982).The criterion on which the preferred
plan was finally selected in these activities was least present-
worth cost based on economic parameters established in (Acres
1982).
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1.2 -Environmental Assessment
The selected potential non-Susitna hydro developments (Table
LID .13)were ra nked in terms of thei r economi c cost of energy.
These developments were then introduced into the all-thermal
generating scenario in groups of two or three.The most economic
schemes were introduced f"irst followed by the less economic
schemes.
On the basis of these evaluations,the most viable alternative to
the Susitna project was found to be the development of the
Chakachamna,Keetna,and Snow sites for hydroelectric power,
supplemented with a thermal generating facility.The potential
environmental impacts of hydroelectric development at these sites
are discussed below;discuss i on of the environmental effects of
thermal development is in Section 3.1.
1.2 -Environmental Assessment of Selected Alternative Sites
The analysis of alternative development scenarios outside the upper
Sus itna Ba sin showed Cha kachamna,Snow and Keetna hydroel ectric sites
offer the most suitable schemes for development.Because maximum total
power production from these three sites would be only 650 MW,addi-
tional thermal and tidal development would also be required (Figure
E.10.3).The potential environmental impacts of hydroelectric develop-
ment at these three sites are discussed below;coal-fired thermal and
tidal power are discussed in Sections 4.1 and 4.2.
The Chakachamna area has been studied previously for hydroel ectric
development and is currently under study by the Power Authority
(Bechtel 1981).As such,fairly detailed information is available.
Keetna and Snow,however,have not been intensively studied and inform-
ation is limited primarily to non-specific inventory data and resource
maps.
1.2.1 -Description of Chakachamna Site
Chakachamna Lake is located in the Al aska range approximately
80 miles (128 km)west of Anchorage.The lake is drained by the
Chakachatna River which runs southeasterly out of the lake and
eventually into Cook Inlet.The most likely developnent of
Chakachamna Lake woul d be wi th a 1ake tap of Chakachamna Lake
with a diversion tunnel (approximately 23 feet (8 meters)in
diameter)to the MacArthur River Basin.This development would
provide some allocation of water for fish purposes.The power
plant would have an installed capacity of 330 MW and could pro-
vide approximately 1446 GWH of firm energy.Transmission lines
would run from the site to a location near the Chugach Electric
Association (CEA)Beluga power plant and would then parallel
existing lines to a submarine crossing of Knik Arm and then to a
terminal on the eastern shore (Bechtel 1981).
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1.2 -Environmental Assessment
(a)Topography and Geology
Chakachamna Lake is located in a deep valley of the Alaska
range surrounded by glaciers and high mountains.From an
elevation of approximately 1200 feet (360 meters).1 and
elevation drops fairly rapidly to sea level within 40 miles
(64 km).In lower elevations,drainage is poor with numer-
ous wetlands present.
Lake Chakachamna was formed by the Barri er Gl acier and asso-
ciated morainal deposits descending from the south side of
Mount Spu rr.The area is underl ai n by semi -consol i dated
vol cani c debri s of 1 ate Tert i ary or Quaternary age and,
closer to Cook Inlet,by alluvial and tidal sand,silt,and
gravel of Holocene age (CIRI/Placer 1981a).Past movement
by glaciers has resulted in scattered boulders and glacially
scattered till.Chakachamna Lake,the south side of the
Chakachatna River Valley,and the MacArthur River Canyon are
bordered by granitic bedrock.The north side of the
Chakachatna River Valley is bordered by volcanic bedrock.
(b)Su rface Hydrology
Chakachamna Lake is approximately 13 miles (22 km)in length
and is 1.5 to 3.0 miles (2.4 to 4.8 km)wide.Inflow to the
lake is primarily glacial in origin and consists of the
Nagishlamina and Chilligan Rivers entering from the north
(U.S.Fish and Wildlife Service 1962).
The Chakachatna River originates at the outlet of
Chakachamna Lake and flows easterly approximately 15 mil es
(24 km)through a canyon and then through lowland areas to
Cook Inlet.Mean annual discharge at its origin is 3645 cfs
with a range from 441 cfs in April to 12,000 cfs in July;
average annual stream flow at the reservoi r site is est i-
mated at 2.5 million acre feet (Bechtel 1981).The total
length is 36 miles (57 kmi and the total drainage area is
1620 square miles (4212 km ).
The MacArthur River originates from the MacArthur Glacier
and is also fed by the Blockade Glacier.The river is later
joined by waters from Noaukta Slough,which carry water from
the Chakachatna River •.The MacArthur River continues to the
confluence with the Chakachatna and then empties into
Trading Bay.
(c)Terrestrial Ecology
Vegetation in the project area varies with elevation and
moisture conditions.The major community types present
E-I0-8
F-
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1.2 -Environmental Assessment
include spruce forest,bogs,and willow thickets.Dominant
species present include paper birch,black cottonwood,
alder,bog blueberry,and willow (Bechtel 1981).
Big game species utilizing the area include moose,caribou,
black bear,and grizzly bear.Other species present include
wolverine,mink,and various small mammals (Bechtel 1981).
Birds present in the area are typical for the area of
Maska,with peak numbers and species occurring during the
spring and fall migration periods.Goldeneyes were observed
nesting in the area in 1960 with other waterfowl species
present during migration,including redheads,greenwinged
teal and mallards.Bald eagles and trumpeter swans are
known to nest in the area primarily near Cook Inlet (Bechtel
198!}•
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(d)Aquatic Ecology
The water of the tributaries to Chakachamna Lake,the lake
itsel f,and the Chakachatna and MacArthur Ri vers provide a
variety of water temperatures,water quality and substrate,
resulting in various types of aquatic habitats.
Chakachamna Lake contains populations of lake trout,Dolly
Varden,whitefish and sculpins (U.S.Fish and Wildlife Ser-
vice 1962).Other species present in tri butaries and the
lake include all five species of Pacific salmon found in
Al aska,Dolly Varden,rai nbow trout,pygmy and round white-
fish.These species are found in both drainages.Salmon
spawning in the Chakachatna River drainage and its tributar-
ies occurs primarily in tributaries and sloughs.A rela-
tively small percentage of the 1982 estimated escapement was
observed to occur.in mainstream or side-channel habitats of
the Chakachatna River.The largest salmon escapement in the
CAakachatna drainage was estimated to occur in the Chi 11 egan
and Igitna Ri vers upstream of Chakachatna Lake.The esti-
mated escapement of these sockeye in 1982 was approximately
41,000 fish,71.5 percent of the estimated escapement within
the Chakachatna drainage.Chakachatna Lake is the major
rearing habitat for these sockeye (Bechtel 1983).
The MacArthur Ri ver supports a fi shery simil ar to that of
the Chakachatna (Alaska Power Administration 1980).Dolly
Varden are present with chi nook,coho,pi rlk,sockeye,and
chum salmon present as spawners in the side channels.Pygmy
whitefish occur further downstream (Bechtel 1981).
The MacArthur Ri ver supports a fi shery simil ar to that of
the Chakachatna (Alaska Power Administration 1980).Dolly
E-I0-9
1.2 -Environmental Assessment
Varden are present with chi nook,coho,pi nk,sockeye,and
chum salmon present as spawners in the side channels.Pygmy
whitefish occur further downstream (Bechtel 1981).
In the McArthur River over 90 percent of the estimated sal-
mon escapement occurred in tributaries during 1982.The
estimated escapement of salmon of all species was slightly
greater in the McArthur than the Chakachatna drai nage.
Other anadromous fish including enlachon,bering cisco,
longfin smelt and rainbow'smelt have been found in the
McArthur Ri ver.
The contritution of salmon stocks originating in these sys-
tems to the Cook Inlet corrunercial catch is presently un-
known.Altho~gh some commercial and subsistance fishing
occurs,the extent to which the stock is exploited is also
not known.
Rearing habitat for juvenile anadromous and resident fish is
found throughout both ri vers.Although the waters withi n
the Chakachatna River Canyon below Chakachatna Lake and the
headwaters of the McArthur River do not appear to be import-
ant rearing habitat.There appears to be extensive movement
of fish within and between the drainages,and seasonal
changes in distribution have been noted (Bechtal 1983).
(e)Land Use
Land ownership in the project area is complex and changing,
due to unsettled state selections and native selections.
The federal government via the Bureau of Land Management is
the largest land owner in the area and owns all the land
bordering Chakachamna Lake.Lake Clark National Park is
located immediately west of Chakachamna Lake.Land owner-
ship downstream of the present area is mixed and incl udes
the state (primarily in the Trading Bay State Game Refuge)
and two native corporations,Cook Inlet Region,Inc.and
Tyonek Native Corporation (Bechtel 1981).
Land use in the area is mi xed.In 1947 1ands in the imme-
diate vicinity of Lake Chakachamna were designated as Power
Site Classification 395.The remaining BLM land is pas-
sively managed.State land is managed for recreation.
Other existing and potential land use in the area include
timber harvesting,coal mining,and petroleum exploration.
Scenic resources include views of the lake,river,and
gorges against the mountains.These are typical of this
area of Alaska.The canyon area upstream from the dam is
considered a high quality visual resource (Bechtel 1981).
E-10-10
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1.2 -Environmental Assessment
(f)Cultural Resources
The Alaska Heritage Resource Survey File maintained by the
State Historic-Preservation Office lists no sites present in
the Chakachamna project area.The area has not been thor-
oug hly studi ed and fu rther invest igat ions woul d be neces sary
should the project proceed.
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(g)Soc i oeconomi cs
The Chakachamna project is located ina sparsely popul ated
area of the Kenai Peninsula Borough.The only community in
the vicinity of the project area is the native village of
Tyonek,.population 239 •.Commercial fishing and subsistence
activities are the major sources of income with some employ-
ment provided by timber harvesting,gas and oil exploration
activities,and government employment •
Housing consists primarily of prefabricated structures.One
school serves grades K through 12,with a current enrollment
of 146.Police protection is provided by the Alaskan State
Troopers,headed by a resident constable.Fi re protection
is provided by the U.S.Bureau of Land Management.Medi cal
servi ces are avai 1ab le ina med i ca 1 center located in the
village.Water is supplied from a nearby lake and waste-
water disposed via septic systems.Transportation is
limited to gravel surface roads and small airstrips.
The Kenai Borough and City of Anchorage lNould likely con-
tribute to the work force for the project.The work force
in the Borough is 12,300,with 9.8 percent unemployed;
Anchorage has a work force of 91,671,with 6.9 percent
unemployment (Bechtel 1981).
1.2.2 -Description of Snow Site
The Snow site is located on the Snow River in the Kenai Peninsula
(Figure E.10.2).Power development would include a dam with
diversion through a tunnel approximately 7500 to 10,000 feet (2250
to 2810 meters)in length.A transmission line would extend from
the site northward for nine mil es to Kenai Lake and then north-
westerly for 16 miles (26 km)to tie in with existing lines.The
project area is located within the Chugach National Forest,which
is managed for multiple use.No wilderness areas are present,and
scenic quality is typical for this part of Alaska.
The Snow Ri ver at the proposed damsite flows in a deep narrow
gorge cut into bedrock on the floor of a glacial valley.Gray-
wacke and slate are exposed and this overburden is evident (u.S.
E-10-11
1.2 -Environmental Assessment
Department of Energy 1980).The river flows west and north into
the south end of the Kenai Lake.The average annual streamflow
at the damsite is estimated at 510,000 to 535,000 acre-feet.
The damsite would be fed by 105 square miles (273 km 2 )of the
river's 166 square miles (431 km 2 )drainage area (U.S.
Department of Energy 1980).
Vegetation in the area is primarily a hemlock-spruce forest.
Black bear,wolf and da11 sheep are known to occur in the area,
and a moose concentration area is present.Waterfowl utilize the
area both for nesting and molting.
No anadromous fish are known to occur in the Snow River,but
sockeye and coho salmon are present in the drainage.Rainbow
trout and whitefish also occur in Kenai Lake.
Reports consulted listed no known cultural resource sites in the
Snow area.
1.2.3 -Description of Keetna Site
The Keetna site is located on the Talkeetna River,approximately
70 miles (112 km)north of Anchorage (Figure E.10.2).Power
development would include a dam with a diversion tunnel.
The Talkeetna River,with headwaters in the Talkeetna Mountains,
flows southwesterly to its confl uence with the Susitna Ri ver.
The damsite has a drainage area of 1260 square miles
(3276 km 2 );'stream flow records indicate discharge at the site
to be 1,690,000 acre feet (U.S.Department of Energy 1980).
Vegetation on the lower elevations of the valley is primarily
upland spruce-hardwood forest;the upper elevations have little
vegetation.B1 ack bear and brown bear are present and the area
is a known moose concentration area.A caribou winter range is
nearby.
Four species of anadromous fish are present in the area (chinook,
sockeye,coho,and chum salmon).The chinook salmon is known to
spawn in tributaries upstream from the proposed site.
Reports consulted listed no known cultural resources at the
site.The area is within the Matanuska-Susitna Borough.No 1 and
uses which would preclude development were identified.Aesthetic
resources include views of rivers,trees,and mountains typical
for this portion of Alaska.
E-10-12
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I
1.2 -Environmental Assessment
1.2.4 -Environmental Impacts of Selected Alternatives
Most environmental impacts at the Chakachamna,Snow and Keetna
sites would be those that typically occur with hydroelectric
development.Vegetat i on and wi 1 dl ife habitat woul d be lost,
resulting in a reduction in carrying capacity and wildlife popu-
lations at the site.Based on the availability of habitat in
surrounding areas,this would likely not be a major impact.
Reductions in fi sh populations would reduce the food source for
bears,eagles,and other fish-eating wildlife;this could affect
local populations.Creation of a reservoir at the Snow and
Keetna sites would provide a different habitat type and benefit
such species groups as waterfowl and furbearers.
Any archaeological or historic sites in the reservoir areas would
be flooded.On-ground surveys,salvage operations,and protec-
tion of areas outside the reservoir but within the construction
area would mitigate most of these potential impacts.
Since Chakachamna has been designated as a Power Site,land use
impacts would be consisted with the designated use.Development
of the Snow Site,which is within the Chugach National Forest,is
consistent with multiple use concept of management but could con-
flict with recreational land uses.Development at Keetna appears
.'to be consistent with existing land use,although it is rela-
ti vely undeveloped..
The Keetna reservoir would inundate two scenic areas;Sentinel
Rock and Granite Gorge.Aesthet ic irnpacts at Chakachamna woul d
be greatest during construction.Because the most likely
scenario does not include construction of a dam,aesthetic
impacts following construction should be sl ight.Development of
the Snow Site would not impact any designated scenic areas but
would result in the presence of a dam and associated facilities
with associated impacts to the general aesthetic qual ity of the
area.
Socioeconomic impacts would be similar at each site.It is.
expected there woul d be an increase in popul at ion in the towns
near the site and associated increase in demand for housing,
schools and other services.Because all three sites are located
within 100 miles (160 km)of Anchorage,it is expected much of
the labor force would be drawn from this area where an adequate
work force is present.Construction camps would likely be
erected to hou se workers,ttlereby reduc ing demand on'surround i ng
towns.Soci oeconomi c impacts for the Chakachamna site woul d be
similar to those described for thermal development but of lesser
magnitude.
E-10-13
1.3 -Middle Susitna Basin Hydroelectric Alternatives
The greatest potential impact of these developments is to the
fisheries resources,particularly at the Chakachamna site.
Creation of the reservoir at the·Keetna and Snow sites would
flood river areas,thereby reducing this type of habitat.At the
Keetna site,spawning areas may be affected and upstream migra-
tion of the anadromous salmon also curtailed,unless fish ladders
are constructed and adequate downstream flows maintained.At
the Keetna site,spawning areas may be affected and upstream
migration of the anadromous salmon also curtailed,unless fish
ladders are constructed and adequate downstream flows maintained.
At this time,the detailed studies necessary to determine
adequate flows for power generation and fishery maintenance have
not been conducted.
Dam and power development at the Chakachamna site has the poten-
tial to negatively impact anadromous fish.This impact would
resul t from decreased fl owi ng or dewateri ng from the upper por-
tions of the Chakachatna River,alterations in water quality,
loss of spawning habitat,loss of downstream migrants,or
decrease in the food base.All of these impacts,if large
enough,could impact the commercial fisheries of Cook Inlet;the
magnitude of these impacts would depend upon the design and
operating scheme to produce power.Tunnel alternatives would
likely result in impacts less severe than the dam scheme.Quan-
titative information is not currently available to differentiate
impacts;however,the Chakachatna River is considered an import-
ant contributor to the Cook Inlet fishery.
The diversion into the MacArthur River via tunnels would
increase flows and could result in changes in water quality and
temperature,perhaps affecting the ability of anadromous fish to
migrate upstream to the spawning areas.
1.3 -Middle Susitna Basin Hydroelectric Alternatives
A second feature of the alternatives'analysis involved the considera-
tion of alternative sites within the middle Susitna Basin.This pro-
cess involved consideration of technical,economical,environmental,
and social aspects.
This section describes the environmental consideration involved in the
selection of Devil Canyon/Watana sites as the preferred sites within
the middle Susitna Basin and also presents a brief comparison of the
environmental impacts associated with alternatives that proved economi-
cally feasible.This section concentrates on the environmental aspects
of the selection process.Details of the technical and economic as-
pects of this evaluation are discussed in Acres (1981)and al so in
Acres (1982).
E-10-14
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
The objectives of the selection process were to determine the optimum
Susitna Basi n Development Pl an and to conduct a prel imi nary envi ron-
mental assessment of the alternatives in order to compare those judged
economically feasible.The selection process followed the Generic Plan
Formulation and Selection Methodology described in Exhibit B.Damsites
were identified following the objectives described above.These sites
were then sc reened and assessed through a sequent i alII na rrowi ng down II
process to arrive at a recommended plan (Figure E.10.4).
1.3.1 -Damsite Selection
In the previous Susitna Basin studies discussed in Acres (1982),
12 damsites were identified in the upper portion of the basin,
i.e.,upstream from Gold Creek (see Figure E.10.5).These sites
are listed below:
-Gold Creek;
-Olson (alternative name:Susitna II);
-Devil Canyon;
-High Devil Canyon (alternative name:Susitna I);
-Devil Creek;
-Watana;
-Su sit na II I;
Vee;
-Macl aren;
-Denali;
-Butte Creek;and
-Tyone.
Longitudinal profiles of the Susitna River and probable typical
reservoir levels associated with the selected sites were prepared
to depict which sites were mutually exclusive,i.e.,those which
cannot be developed jointly since the downstream site would inun-
date the upstream site.All relevant data concerni ng dam type,
capital cost,power,and energy output were assembl ed (Ac res
1982).Results appear in Table E.10.14.
1.3.2 -Site Screening
The objective of this screening exercise was to eliminate sites
which would obviously not feature in the initial stages of a
Susitna Basin development plan and which,therefore,do not re-
quire any further study at this stage.Three basic screening
criteria were used;these include environmental,alternative
sites,and energy contribution.
E-10-15
1.3 -Middle Susitna Basin Hydroelectric Alternatives
(a)Environmental Screening Criteria
The potential impact on the envi ronment of a reservoir
located at each of the sites was assessed and catagorized as
being relatively unacceptable,significant,or moderate.
(i)Unacceptable Sites
Sites in this category were classified as unaccept-
able because either their impact on the envi ronment
would be extremely severe or there are obviously
better alternatives available.Under the current
circumstances,it is expected that it would be
di Hi cult to obta i n the necessa ry agency approval,
permits,and licenses to develop these sites.
The Gold Creek and 01 son sites both fall into this
category.Since salmon are known to migrate up
Portage Creek,a development at either of these sites
would obstruct this migration and inundate spawning
grounds.Available information indicates that salmon
do not mi grate through Devil Canyon to the ri ver
reaches beyond because of the steep fall and high
flow velocities.
Development of the mi d-reaches of the Tyone Ri ver
would result in the inundation of sensitive big game
and waterfowl areas,provide access to a large
expanse of wilderness area,and contribute only a
small amount of storage and energy to any Susitna
development.Since more acceptable alternatives are
obviously available,the Tyone site is also consid-
ered unacceptable.
(ii)Sites With Significant Impact
Between Devil Canyon and the Oshetna River,the
Susitna River is confined to a relatively steep river
vall eYe Upstream from the Oshetna Ri ver the
surrounding topography fl attens,and any development
in this area has the potential of flooding large
areas even for relatively low dams.Since the Denali
Highway is relatively close,this area is not as
isolated as the Upper Tyone River Basin.It is still
very sensitive in terms of potential impact on big
game and waterfowl.The sites at Butte Creek,
Denali,Maclaren,and to a lesser extent,Vee,fit
into this category.
E-10-16
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
(iii)Sites With Moderate Impact
Sites between Devil Canyon and the Oshetna River have
a lower potential envi ronmental impact.These sites
include the Devil Canyon,High Devil Canyon,Devil
Creek,Watana and Susitna sites,and to a lesser
extent,the Vee site.
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,....
(b)
(c)
(d)
Alternative Sites
Sites which are close to each other and can be regarded as
alternative dam locations can be treated as one site for
project definition study purposes.The two sites which fall
into this category are Devil Creek,which can be regarded as
an alternati ve to the Hi gh Devil Canyon site,and Butte
Creek,which is an alternative to the Denali site.
Energy Cohtribution
The total Susitna Basin potential has been assessed at 6700
GWh.As discussed in the load forecasts in Exhibit B,addi-
tional future energy requirements for the period 1982 to
2010 a re forecast to range from 2400 to 13,500 GWh.-It was
therefore decided to 1 imit the minimum size of any power
development in the Susitna Basin to an average annual energy
production in the range of 500 to 1000 GWh.The upstream
sites such as Macl aren,Denal i,Butte Creek,and Tyone do
not meet thi s mi nimum energy generation criterion.
Screening Process
The screening process involved eliminating all sites falling
in the unacceptable environmental impact and alternative
site categories.Those failing to meet the energy contribu-
tion criteria were also eliminated unless they had some
potential for upstream regulation.The results of this
process are as follows:
-The unacceptabl e si te envi ronmental category el imi nated
the Gold Creek,C~son,and Tyone sites;
-The alternative sites category el iminated the Devil Creek
and Butte Creek sites;and
-No additional sites were eliminated for failing to meet
the energy contribution criteria.The remaining sites
upstream from Vee,i.e.,Macl aren and Denal i,were
retai ned to insure that further study be di rected toward
determining the need and viability of providing f10w
regulation in the headwaters of the Susitna.
E-10-17
1.3 -Middle Susitna Basin Hydroelectric Alternatives
1.3.3 -Formulation of Susitna Basin Development Plans
In order to obtain a more uniform and reliable data base for
studying the seven sites remai ning,it was necessary to develop
engineering 1ayouts for these sites and re-eval uate the costs.
In addition,it was also necessary to study staged developments
at several of the larger dams.These layouts were then used to
assess the sites and plans from an environmental perspective.
The results of the site-screening exercise described above indi-
cate that the Susitna Basin Development Plan should incorporate a
combination of several major dams and powerhouses located at one
or more of the following sites:
-Devil Canyon;
-High Devil Canyon;
-Watana;
-Susitna III;or
-Vee.
In addition,the following two sites should be considered as
candidates for supplementary upstream flow regulation:
-Maclaren;and
-Denali.
To establish very quickly the likely optimum combination of dams,
a computer screening model was used to directly identify the
types of pl ans that are most economi c.Resul ts of these runs
indicate that the Devil Canyon/Watana or the Hi gh Devil Canyon/
Vee combinations are the most economic.In addition to these two
basic development plans,a tunnel scheme which provides potential
environmental advantages by replacing the Devil Canyon dam with a
long power tunnel,and a development plan involving the two most
economic damsites (High Devil Canyon and Watana)were also intro-
duced.These studies are described in more detail in Table
L10.15.
-Devil Canyon;
-High Devil Canyon;
-Watana;
-Susitna III;or
-Vee.
These studies resulted in three basic plans involving dam combi-
nations and one darn/tunnel combination.Plan 1 involved the
Watana-Oevil Canyon sites,Plan 2 the High Devil Canyon-Vee
sites,Plan 3 the Watana-tunnel concept,and Plan 4 the
Watana-High Devil Canyon sites.
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
(a)Plan 1
Three subplans were developed:
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(i )
(i i )
(iii)
(b)Plan 2
Subplan 1.1
Stage 1 involves constructing Watana Dam to its full
height and installing 800 MW.Stage 2 involves
constructing Devil Canyon Dam and installing 600 MW.
Subplan 1.2
For this subplan,construction of the Watana dam is
staged from a crest elevation of 2060 feet to 2225
feet (621 m to 667 m).The powerhouse is also staged
from 400 I~W to 800 MW.As for Subplan 1.1,the final
stage involves Devil Canyon with an installed
capacity of 600 MW.
SUbplan 1.3
This subplan is similar to Subplan 1.2 except that
only the powerhouse and not the dam at Watana is
staged.
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Three subplans were also developed under Plan 2:
(i)Subplan 2.1
This subplan involves constructing the High Devil
Canyon dam fi rst with an install ed capacity of 800
MVJ.The second stage involves constructing the Vee
dam with an installed capacity of 400 MW •
(ii)Subplan 2.2
For this subplan,the construction of High Devil
Canyon Dam i.s staged from a crest el evati on of 1630
to 1775 feet (438 m to 482 m).The installed
capacity is al so staged from 400 to 800 MW.As for
Subplan 2.1,Vee follows with 400 MW of installed
capacity.
(iii)Subplan 2.3
This subplan is similar to Subplan 2.2 except that
only the powerhouse and not the dam at Hi gh Devi 1
Canyon is staged.
E-10-19
1.3 -Middle Susitna Basin Hydroelectric Alternatives
(c)Plan 3
This plan involves a long power tunnel to replace the Devil
Canyon dam in the Watana/Devil Canyon development plan.The
tunnel alternative could develop similar head as the Devil
Canyon dam development and would avoid some environmental
impacts by avoi di ng tIle i nundati on of Devi 1 Canyon.Because
of low winter flows in the river,a tunnel alternative was
consi dered only as a second stage to the Watana develop-
ment.
A plan involving a tunnel to develop the Devil Canyon dam
head and a 245-foot-high (73-m)re-regulation'dam and
reservoir was selected with the capacity to regulate diurnal
fluctuations caused by the peaking operation at Watana.The
plan involves two subplans.
(i)Subplan 3.1
This subplan involves initial construction of Watana
and installation of 800 MW of capacity.The next
stage i nvol ves the construction of the downstream
re-regulation dam to a crest elevation of 1500 feet
(450 m)and a 15-mile-long (24 km)tunnel.A total
of 300 MW would be installed at the end of the tunnel
and a further 30 MW at the re-regul ation dam.An
additional 50 MW of capacity would be installed at
the Watana powerhouse to facil itate peaki ng opera-
tions.
(ii)Subplan 3.2
This subplan is essentially the same as Subplan 3.1
except that construction of the initial 800-MW power-
house at Watana is staged.
(d)Plan 4
This single plan was developed to evaluate the development
of the two most economi c damsites (Watana and Hi gh Devi 1
Canyon)jointly.Stage 1 involves constructing Watana to
its full height with an installed capacity of 400 MW.Stage
2 involves increasi ng the capacity at Watana to 800 MW.
Stage 3 i nvo 1ves constructing Hi gh Devi 1 Canyon to a crest
elevation of 1470 feet (441 m)so that the reservoir extends
to just downstream from Watana.In order to develop the
full head between Watana and Portage Creek,an additi onal
smaller dam would be added downstream from High Devil
Canyon.This dam would be located just upstream from
E-I0-20
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
Portage Creek so as not to interfere with the anadromous
fisheries.It would have a crest elevation of 1030 feet
(310 m)and an installed capacity of 150 MW.For purposes
of these studi es,this site is referred to as the Portage
Creek site.
1.3.4 -Plah Evaluation Process
The overall objective of this step in the evaluation process was
to select the preferred basin development plan.A prelim"inary
evaluation of plans was initially undertaken to determine broad
comparisons of the available alternatives.This was followed by
appropriate adjustments to the plans and a more detailed evalua-
tion and comparison.
Table E.I0.14 lists pertinent details such as capital costs and
energy yields associated with the selected plans.The cost
information was obtained from the engineering layout studies.
The energy yield information was developed using a multi-
reservoir computer model.
A more detailed description of the model appears in Acres
(1982).
In the process of eval uating the schemes,it became apparent that
there woul d be envi ronmental probl ems associ ated with all owi ng
daily peaking operations from the most downstream reservoir in
each of the plans described above.In order to avoid these
potential problems while still maintaining operational flexibil-
ity to peak on a daily basis,re-regulation facilities were
incorporated in the four basic plans.These facilities incorpo-
rate both structural measures,such as re-regulation dams,and
modified operational procedures under a series of four modified
plans,El through E4.
(a)El Plans
For Subplans 1.1 to 1.3,a low,temporary re-regulation dam
woul d be constructed downstream from Watana duri ng the stage
in which the generating capacity is increased to 800 MW.
This dam would re-regulate the outflows from Watana and
allow daily peaking operations.It has been assumed that it
would be possible to incorporate this dam with the diversion
works at the Devil Canyon site,and an allowance of $100
mi 11 i on has been made to cover any add it i ona 1 costs asso-
ciated with this approach.
In.the final stage,only 400 MW of capacity would be added
to the dam at Devi 1 Canyon instead of the ori gi nal 600 MW.
E-I0-21
1.3 -Middle Susitna Basin Hydroelectric Alternatives
Reservoir operating rules are changed so that Devil Canyon
Dam acts as the re-regulation dam for Watana.
(b)E2 Plans
For Subplans 2.1 to 2.3,a permanent re-regulation dam would
be located downstream from the High Devil Canyon site,while
at the same time,the generating capacity would be increased
to 800 MW.An allowance of $140 mill ion has been made to
cover the costs of such a dam.
An additional Subplan E2.4 was established.This plan is
s"imilar to E2.3 except that the re-regulation dam would be
ut i 1 i zed for power product i on.The dams i te woul d be located
at the Portage Creek site with a crest level set to utilize
the full head.A 150-MW powerhouse would be installed.
Since this dam is to serve as a re-regulating facility,it
would be constructed at the same time as the capacity of
High Devil Canyon is increased to 800 MW,i.e.,during Stage
2.
(c)E3 Pl an
The Watana tunnel development pl an al ready incorporates an
adequate degree of re-regulation,and the E3.1 Plan is,
therefore,identical to the 3.1 Plan.
(d)E4 Plans
The E4.1 Plan incorporates a re-regulation dam downstream
from Watana duri ng Stage 2.As for the E1 Pl ans,it has
been assumed that it would be possible to incorporate this
dam as part of the diversion arrangements at the High Devil
Canyon site,and an allowance of $100 million has been made
to cover the costs.The energy and cost i nformat i on for
these plans is presented in Exhibit B.'
These evaluations basically reinforce the results of the
screening model;for a total energy production capability of
up to approximately 4000 GWh,Plan E2 (High Devil Canyon)
prov i des the most economic ener.gy,wh i 1e for capabil iti es in
t he range of 6000 GWh,Pl an E1 (Watana-De vil Canyon)is th e
most economic.
1.3.5 -Comparison of Plans
The evaluation and comparison of the various basin development
plans described above was undertaken in a series of steps.
E-1O-22
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
In the fi rst step,for determining the optimum staging concept
associated with each basic plan (i .e.,the optimum subplan),
economi c criteri a only were used and the 1east-cost stagi ng
concept was adopted.Fo r assessi ng whi ch pl an is the most appro-
priate,a more detailed evaluation process incorporating eco-
nomic,environmental,social,and energy contribution aspects was
taken into account.
Economic evaluation of the Susitna Basin developnent plans was
conducted via a computer simulation planning model (OGP5)of the
entire generating system.This model and the results are
described in (Acres 1982).
As outlined in the generic methodology (Exhibit B),the final
evaluation of the development plans is to be undertaken by a
perceived comparison process on the basis of appropriate
criteri a.The followi ng c riteri a were used to eval uate the
shortl i sted bas in development pl ans.They generally contai n the
requi rements of the generic process with the exception that an
additional criterion,energy contribution,was added.The objec-
tive of including this criterion was to insure that full consid-
eration is given to the total basin energy potential that is
developed by the various plans.
(a)·Economic Criteria
The parameter used was the total present-worth cost of the
total Rai"lbelt generating system for the period 1980 to 2040
listed and discussed in Exhibit B.
(b)Environmental Criteria
A qualitative assessment of the environmental impact on the
ecological,cultural,and aesthetic resources was undertaken
for each plan.Emphasis was placed on identifying major
concerns.so that these coul d be combined with the other
evaluation attributes in an overall assessment of the plan.
(c)Social Criteria
This attribute includes determination of the potential non-
renewable resource displacement,the impact on the state and
local economy,and the ri sks and consequences of major
structural failures caused by seismic events.Impacts on
the economy refer to the effects of an investment pl an on
economic variables.
E-10-23
1.3 -Middle Susitna Basin Hydroelectric Alternatives
(d)Energy Contribution
The parameter used was the total amount of energy produced
from the specific development plan.An assessment of the
energy development foregone was al so undertaken.This·
energy loss is inherent to the plan and cannot easily be
recovered by subsequent staged developments.
Economic and technical comparisons are discussed in Exhibit
B;environmental,social,and summary comparisons appear in
Tables E.10.16 through E.10.18.
1.3.6 -Results of Evaluation Process
The various attributes outlined above have been determined for
each plan.Some of the attributes are quantitative while others
are qualitative.Overall evaluation was based on a comparison of
similar types of attributes for each plan.In cases where the
attributes associated with one plan all indicated equal ity or
superiority with respect to another plan,the decision as to the
best plan was clear cut.In other cases where some attributes
indicated superiority and others inferiority,these differences
were highlighted and trade-off decisions were made to determine
the preferred development pl an.In cases where these trade-offs
had to be made,they were relatively convincing and the decision-
maki ng process was,therefore,regarded as fai rly robust.In
addition,these trade-offs were clearly identified so the reader
can independently address the judgment decisions made.
The overall evaluation process was conducted in a series of
steps.At each step,only a pai r of pl ans was evaluated.The
superior plan was then passed on to the next step for evaluation
against an alternative plan.
1.3.7 -Devil Canyon Dam Versus Tunnel
The first step in the process involves the evaluation of the
Watana-Devil Canyon dam plan (E1.3)and the Watana tunnel plan
(E3.1).Since Watana is common to both plans,the evaluation is
based on a comparison of the Devil Canyon dam and tunnel
schemes.
In order to assist in the evaluation in terms of economic cri-
teria,additional information was obtained by analyzing the
results of the OGP5 computer runs.This i nformat ion,presented
in Exhibit B,illustrates the breakdown of the total system
present-worth cost in terms of capital investment,fuel,and
operation and maintenance costs.
E-10-24
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
(a)Economic Comparison
From an economic point of view,the Devil Canyon dam scheme
is superior.On a present worth basi s,the tunnel scheme is
$680 mill ion,or about 12 percent more expensi ve than the
dam scheme.For a low-demand growth rate,this cost differ-
ence would be reduced slightly to $610 million.Even if the
tunnel scheme costs are halved,the total cost difference
would still amount to $380 million.Consideration of the
sensitivity of the basic economic evaluation to potential
changes in capital cost estimate,the period of economic
analysi s,the discount rate,fuel costs,fuel cost escal a-
tion,and economic plant lives does not change the basic
economic superiority of the dam scheme over the tunnel
scheme.
(b)Environmental Comparison
The environmental comparison of the two schemes is summar-
ized in Table E.I0.16.Overall,the tunnel scheme is judged
to be superi~r because:
-It offers the potential for enhancing anadromous fish
populations downstream from the re-regulation dam because
of the more uniform flow distribution that will be
achieved in this reach;
-It inundates 13 miles (21 km)less of resident fisheries
habitat in river and major tributaries;
-It has a lower impact on wil dl ife habitat because of the
smaller inundation of habitat by the re-regu1ation dam;
-It has a lower potential for inundating archaeological
sites because of the smaller reservoir involved;and
-It would preserve much of the characteristics of the Devil
Canyon gorge,which is considered to be an aesthetic and
recreational resource.
(c)Social Comparison
Table LI0.17 summarizes the evaluation in terms of the
social criteria of the two schemes.In terms of impact on
state and local economics and risks resulting from seismic
exposure,the two schemes are rated equally.However,the
dam scheme has,because of its higher energy yield,more
potential for displacing nonrenewable energy resources,and,
therefore,scores a sl i ght overall p1 us in terms of the
social evaluation criteria.
E-I0-25
1.3 -Middle Susitna Basin Hydroelectric Alternatives
(d)Energy Comparison
The results show that the dam scheme has a greater potential
for energy production and develops a larger portion of the
basin's potential.The dam scheme is,therefore,judged to
be superior from the energy contribution standpoint.
(e)Overall Comparison
The overall evaluation of the two schemes is summarized in
Table E.10.18.The estimated cost saving of $680 million in
favor of the dam scheme is considered to outweigh the reduc-
tion in the overall environmental impact of the tunnel
scheme.The dam scheme is,therefore,judged to be superi or
overall.
1.3.8 -W~tana-Devil Canyon Versus High Devil Canyon-Vee
The second step in the development selection process involves an
evaluation of the Watana-Devil Canyon (E1.3)and the High Devil
Canyon-Vee (E2.3)development plans.
(a)Economic Comparison
In terms of the economic criteria,the Watana-Devil Canyon
plan is less costly by $520 million.As for the dam-tunnel
evaluation discussed above,the sensitivity of this decision
to potential changes in the various parameters considered
(i .e.,load forecast,discount rates,etc.)does not change
the basic superiority of the Watana-Devil Canyon Plan.
(b)Environmental Comparison
The evaluation in terms of the environmental criteria is
summarized in Table E.10.19.In assessing these plans,a
reach-by-reach compa ri son was made for the secti on of the
Susitna Ri ver between Portage Creek and the Tyone Ri ver.
The Watana-Devi 1 Canyon scheme woul d create more potenti al
environmental impacts in the Watana Creek area.However,it
was judged that the potential environmental impacts which
woul d occur in the upper reaches of the ri ver with a Hi gh
Devil Canyon-Vee development are more severe in compari son
overall.
E-I0-26
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1.3 -Middle Susitna Basin Hydroelectric Alternatives
From a fisheries perspective,both schemes would have a
similar effect on the downstream anadromous fisheries,
al though the Hi gh Devil Canyon-Vee scheme woul d produce a
slightly greater impact on the resident fisheries in the
middle Susitna Basin.
The Hi gh Devil Canyon-Vee scheme woul d inundate approxi-
mately 14 percent (15 miles,or 24 km)more critical winter
riverbottom moose habitat than the Watana-Devil Canyon
scheme.The High Devil Canyon-Vee scheme would inundate a
large area upstream from the Vee site utilized by three sub-
population of moose that range in the northeast section of
the basi n.The Watana-Devi 1 Canyon scheme woul d avoid the
potential impacts on moose in the upper section of the
river;however,a 1 arger percentage of the Watana Creek
basin would inundated.
The condition of the subpopulation of moose utilizing this
Watana Creek basin and the quality of the habitat appears to
be decreasi ng.Habitat mani pul ati on measures coul d be
implemented in this area to improve the moose habitat.
Nevertheless,it is considered that the upstream moose
habitat losses associ ated wi th the Hi gh Devil Canyon-Vee
scheme woul d probably be greater than the Watana Creek
losses associated with the Watana-Devil Canyon scheme •
A major factor to be cons i dered in cornpar"j ng the two devel-
opment plans is the potential effects on caribou in the
region.It was judged that the increased length of river
flooded,especially upstream from the Vee damsite,would
result in the High Devil Canyon-Vee plan creating a greater
potential diversion of the Nelchina herd1s range.In addi-
t ion,a 1arger area of ca ri bou range woul d be directly
inundated by the Vee reservoir.
The area flooded by the Vee reservoir is also considered
important to some key furbearers,particularly red fox.In
a compa ri son of thi s a rea with the Watana Creek a rea that
would be inundated with the Watana-Devil Canyon scheme,the
area upstream from Vee was judged to be more important for
furbearers.
As previously mentioned,the area between Devil Canyon and
the Oshetna River on the Susitna River is confined to a
relatively steep river valley.Along these valley slopes
are habitats important to birds and black bears.
E-10-27
1.3 -Middle Susitna Basin Hydroelectric Alternatives
Si nce the Watana reservoi r woul d flood the ri ver secti on
between the Watana damsite and the Oshetna River to a higher
elevation than would the High Devil Canyon reservoir,the
High Devil Canyon-Vee plan would retain the integrity of
more of this river valley slope habitat.
From the archeological studies done to date,there tends to
be an increase in site intensity as one progresses towards
the northeast section of the middle Susitna Basin.The High
Devil Canyon-Vee plan would result in more extensive inunda-
tion and increased access to the northeasterly section of
the basin.This plan was judged to have a greater potential
for directly or indirectly affecting archeological sites.
Because of the wilderness nature of the upper Susitna Basin,
the creation of increased access associated with project
development could have a significant influence on future
uses and management of the area.The High Devil Canyon-Vee
plan would involve the construction of a dam at the Vee
site and the c reat i on of a reservoi r in the more north-
easterly section of the basin.This plan would thus create
inherent access to more wi 1 derness than woul d the Watana-
Devil Canyon scheme.Since it is easier to extend access
than to limit it,inherent access requirements are detrimen-
tal,and the Watana-Devil Canyon scheme was judged to be
more acceptable in this regard.
Except for the increased loss of ri ver valley,bi rd,and
black bear habitat,the Watana-Devil Canyon development plan
was judged to be more envi ronmentally acceptabl e than the
High Devil Canyon-Vee plan.
Table E.10.17 summarizes the evaluation in tenns of the
social criteria.As in the case of the dam versus tunnel
comparison,the Watana-Devil Canyon plan was judged to have
a slight advantage over the High Devil Canyon-Vee plan
because of its greater potential for displacing nonrenewable
resources.
(c)Energy Comparison
The evaluation of the two plans in tenns of energy contribu-
tion criteria shows the Watana-Devil Canyon scheme to be
superior because of its higher energy potential and the fact
that it develops a higher proportion of the basin's poten-
t i a 1•
E-10-28
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.....1.3 -Middle Susitna Basin Hydroelectric Alternatives
(d)Overall Comparison
The overall evaluation is summarized in Table E.10.20 and
indicates that the Watana-Devil Canyon plans are generally
-superior to all the other evaluation criteria.
1.3.9 -Preferred Susitna Basin Development Plan
Comparisons of the Watana-Devil Canyon plan with the Watana tun-
nel plan and the High Devil Canyon-Vee plans were judged to favor
the Watana-Devil Canyon plan in each case.
The Watana-Devil Canyon pl an was therefore selected as the pre-
ferred Susitna Basin development plan,and a basis for continua-
tion of more detailed design optimization and environmental
studies •
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-E-10-29
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2 -ALTERNATIVE FACILITY DESIGNS
2.1 -Watana Facility Design Alternatives
Envi ronmental factors cons i dered in Watana faci 1ity desi gn are summa-
rized below.
2.1.1 -Diversion/Emergency Release Facilities
Table E.10.28 shows the minimum flow releases from the Watana and
Devil Canyon dams required to maintain an adequate flow at Gold
Creek.These release levels have been established to avoid ad-
verse affects on the Salmon fishery downstream.
At an early,stage of the study,it was established that some form
of low level release facility was required to permit lowering of
the reservoir in the event of an extreme emergency,and to meet
instream flow "requirements during filling,of the reservoir.The
most economical alternative ava"1lable would involve converting
one of the diversion tunnels to permanent use as a low-level out-
let facility.Since it would be necessary to maintain the diver-
sion scheme in service during construction of the low-level out-
let works,two or more diversion tunnels would be required.The
use of two diversion tunnels also provides an additional measure
of security to the diversion scheme in case of the loss of ser-
vice of one tunnel.
2.1.2 -Main Spillway
During development of the general arrangements for both the
Watana and Devil Canyon dams,a restri cti on was imposed on the
amount of excess dissolved nitrogen permitted in the spillway
discharges.Supersaturation occurs when aerated flows are sub-
jected to pressures greater than 30 to 40 feet (9 to 12 m)of
head which forces excess nitrogen into solution.This occurs
when water is subjected to the high pressures that occur in deep
plunge pools or at large hydraulic jumps.The excess nitrogen
would not be dissipated within the downstream Devil Canyon reser-
voir and a buildup of nitrogen concentration could occur through-
out the body of water.It would eventually be discharged down-
stream from Devil Canyon with harmful effects on the fish popula-
tion.On the basis of an evaluation of the related impacts,and
discussions with interested federal and state agencies,spillway
facilities will be designed to limit discharges of water from
either Watana or Devil Canyon that may become supersaturated with
nitrogen to a recurrence period of not less than 1:50 years.
E-10-31
2.1 -Watana Facility Design Alternatives
Three basic alternative spillway types were examined:
-Chute spillway with fl ip bucket;
-Chute spillway with stilling basin;and
-Cascade spillway.
Consideration was also given to combinations of these alterna-
tives with or without supplemental facilities such as valved
tunnels and an emergency spillway fuse plug for handling the PMF
discharge.
The stilling basin spillway is very costly and the operating head
of 800 feet (240 m)is beyond precedent experience.Erosion
downstream shoul d not be a problem but cavi tati on of the chute
coul d occur.Thi s scheme was therefore el im'i nated from further
consideration.
The cascade spillway was also not favored for technical and eco-
nomic reasons.However,this arrangement does have an advantage
in that it provides a means of preventing nitrogen supersatura-
tion in the downstream discharges from the project which could be
harmful to the fish population.A cascade configuration would
reduce the dissolved nitrogen content;hence,this alternative
was retained for further evaluation.The capacity of the cascade
was reduced and an emergency rock channel spi llway was i ncl uded
to take the ext reme fl oods.
2.1.3 -Power Intake and Water Passages
Apart from the potential nitrogen supersaturation problem dis-
cussed above,the major envi ronmental constrai nts on the design
of the power facilities are:
Control of downstream river temperatures;and
-Control of downstream flows.
The intake design has been modified to enable power plant flows
to be drawn from the reservoir at four different levels through-
out the anticipated range of reservoir drawdown for energy pro-
duction in order to control the downstream river temperatures
within acceptable limits.
Minimum flows at Gold Creek during the critical summer months
have been studied to mitigate the project impacts on salmon
spawning downstream from Devi1 Canyon.These minimum flows re-
present a con stra i nt on the reservoi r operation,and i nfl uence
the computation of average and firm energy produced by the
Susitna development.Refer to Chapter 2 and 3 of Exhibit E and
to Section 3 below for further discussion of alternative flow
evaluation.
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2.2 -Devil Canyon Facility Design Alternatives
2.1.4 -Outlet Facilities
As a provision for drawing down the reservoir in case of emer-
gency,a mid-level release will be provided.The intake to these
facilities will be located at depth adjacent to the power facili-
ties·intake structures.Flows will then be passed downstream
through a concrete-lined tunnel,discharging beneath the down-
stream end of the mai n spillway f1 i p bucket.In order to over-
come potential nitrogen supersaturation problems,a system of
fixed-cone valves will be installed at the downstream end of the
outlet facilities.The valves will be sized to discharge in con-
junction with the powerhouse operating at 7000 cfs capacity,the
equi val ent of the routed 50-year flood.
2.2 -Devil Canyon Facility Design Alternatives
2.2.1 -Installed Capacity
The decision to operate Devil Canyon primarily as a base loaded
plant was gove~ned by the following main considerations:
-Daily peaking is more effectively performed at Watana than at
Devil Canyon;and
Excessive fluctuations in discharge from the Devil Canyon dam
may have an undesirable impact on mitigation measures incorpo-
rated in the final design to protect the downstream fisheries.
Given this mode of operation,the required installed capacity at
Devil Canyon has been determi ned as the maximum capaci ty needed
to utilize the.available energy from the hydrological flows of
record,as modified by the reservoir operation rule curves.
2.2.2 -Spillway Capacity
The avoidance of nitrogen supersaturation in the downstream flow
also will apply to Devil Canyon.Thus,the discharge of water
possibly supersaturated with nitrogen from Devil Canyon will be
1imited to a recurrence peri od of not 1es s than 1:50 years by the
use of solid cone valves similar to Watana.
2.2.3 -Power Intake and Water Passages
In addition to potential nitrogen-saturation problems caused by
spi 11 way operati on,the major impacts of the Devil Canyon power
intake facilities development will be:
Changes in the temperature regime of the river;and
-Fluctuations in downstream river flows and levels.
E-10-33
2.3 -Access Alternatives
Temperature modeling has indicated that a multiple level intake
design at Devil Canyon would assist downstream water temperature
control.Consequently,the intake design at Devil Canyon will
incorporate a multi-level draw-off about 80 feet (24 m)below
maximum reservoir operating level of 1455 feet (436 m).
The Devil Canyon station will be operated as a baseloaded plant
throughout the year,in order to maintain constant flow.Refer
to Chapter 2 of Exhibit E for further discussion of this issue.
2.3 -Access Alternatives
2.3.1 -Objectives
Throughout the development,eval uation,and selection of the
access plans,the foremost objective was to provide a transporta-
tion system that would support construction activities and allow
for the orderly development and maintenance of site facilities.
Meeting this fundamental objective involved the consideration not
only of economics and technical ease of development but also many
other diverse factors.Of prime importance was the potential for
impacts to the environment,namely impacts to the local fish and
game populations.In addition,since the Native villages and the
Cook Inlet Region will eventually acquire surface and subsurface
rights,their interests were recognized and taken into account as
were those of the local communities and general public.
With so many different factors i nfl uencing the choice of an
access plan,it was evident that no one plan would satisfy all
interests.The aim during the selection process was to consider
all factors in thei r proper perspective and produce a plan that
represented the most favorable solution to both meeting project-
related goals and minimizing impacts to the environment and
surrounding communities.
2.3.2 -Corridor Identification and Selection
The Acres Plan of Study,February 1980,identified three general
corridors leading from t~e existing transportation network to the
damsites.This network consists of the George Parks Highway and
the Alaska Railroad to the west of the damsites and the Denali
Highway to the north.The three corridors appear in Figure
E.10.6.
E-10-34
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2.3 -Access Alternatives
Corridor 1 -From the Parks Highway to the Watana damsite via the
north side of the Susitna River.
Corridor 2 -From the Parks Highway to the Watana damsite via the
south side of the Susitna River.
Corridor 3 -From the Denali Highway to the Watana damsite.
The access road studies identified a total of eighteen alterna-
tive plans within the three corridors.The alternatives were
developed by laying out routes on topographical maps in accor-
dance with accepted road and rai 1 desi gn criteri a.Subsequent
field investigations resulted in minor modifications to reduce
environmental impacts and improve alignment.
The preliminary design criteria adopted for access road and rail
alternatives were selected on the basis of similar facilities
provided for other remote projects of this nature.Basic roadway
parameters were as follows:
-Maximum grade of 6 percent;
-Maximum curvature of 5 degrees;
-Design loading of 80 k axle and 200 k total during construc-
tion;and
-Design loading of HS-20 after construction.
Railroad design parameters utilized were as follows:
-Maximum grade of 2.5 percent;
-Maximum curvature of 10 degrees;and
-Loading of E-72.
Once the basic corridors were defined,alternative routes which
met these design parameters were established and ev~uated
against technical,economic,and environmental criteria.Next,
within each corridor,the most favorable alternative route in-
terms of length,alignment,and grade was identified.These
routes were then combined together and/or with existing roads or
railroads to form the various access plans.The development of
alternative routes is discussed in more detail in the R & M
Access Pl anni ng St udy,January 1982 and the R&M Access Pl anni ng
Study Supplement,November 1982.These documents contain maps of
all the routes.
2.3.3 -Development of Plans
At the beginning of the study,a plan formulation and initial
selection process was developed.The criteria that most signifi-
cantly affected the selection process were identified as:
E-I0-35
2.3 -Access Alternatives
-Minimizing impacts to the environment;
-Minimizing total project costs;
Provi di ng transportati on fl exi bi 1 ity to mi nimi ze construct i on
risks;
-Providing ease of operation and maintenance;and
-Pre-construction of a pioneer road.
This led to the development of eight alternative access plans.
During evaluation of these access plans,input from the public,
resource agencies,and Native organizations was sought and their
response resulted in an expansion of the original list of eight
alternative plans to eleven.Plans 9 and 10 were added as a sug-
gestion by the Susitna Hydroelectric Steering Committee as a
means of limiting access by having rail only access as far as the
Devil Canyon damsite to reduce adverse envi ronmental impacts in
and around the project area.Plan 11 was added as a way of pro-
viding access from only one main terminus,Cantwell,and thus
alleviate socioeconomic impacts to the other communities in the
Ranbelt (principally Gold Creek,Trapper Creek,Talkeetna and
Hurricane).
Studies of these eleven access plans culminated in the production
of the Acres Access Route Selection Report of March 1982 which
recommended Plan 5 as the route which most closely satisfied the
selection criteria.Plan 5 starts from the George Parks Highway
near Hurricane and traverses along the Indian River to Gold
Creek.From Gold Creek the road continues east on the south side
of the Susitna Ri ver to the Devil Canyon damsite,crosses a low
level bridge and continues east on the north side of the Susitna
Ri ver to the Watana damsite.For the project to remain on sched-
ul e,it woul d have been necessary to construct a pi oneeer road
along this route prior to the FERC 1 icense being issued.
In March of 1982,the Al aska Power Authority presented the
results of the Susitna Hydroelectric Feasibil ity Report,of which
Access Plan 5 was a part,to the publ ic,agencies,and organiza-
tions.During April,comment was obtained relative to the feasi-
bi 1 ity study from these groups.As a resul t of these comments,
the pioneer road concept was eliminated,the evaluation criteria
were refined,and seven additional access alternatives were
developed.
Maps and detailed descriptions of the 18 alternatives considered
are contained in R&M (1982,1982a)and Acres (1982b).The evalu-
ation process is described below.
E-10-36
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2.3 -Access A1ternatives
2.3.4 -Evaluation of Plans
The refined criteria used to evaluate the eighteen aHernative
access plans were:
No pre-license construction;
-Provide initial access within one year;
-Provide access between sites during project operation phase;
-Provide access flexibility to ensure project is brought on-line
within budget and schedule;
-Minimize·total cost of access;
-Minimize initial investment required to provide access to the
Watana damsite;
-Minimize risks to project schedule;
-Minimize environmental impacts;
-Accommodate current land uses and plans;
-Accommodate Agency preferences;
-Accommodate preferences of Native organizations;
-Accommodate preferences of local communities;and
-Accommodate public concerns.
All eighteen plans were evaluated using these refined criteria to
determine the most responsive access p1an "in each of the three
basic corridors.An explanation of the criteria and the plans
which w~re subsequently el iminated is given below.
To meet the overall project schedul e requi rements for the Watana
develo[X11ent,it is necessary to secure initial access to the
Watana damsite within one year of the FERClicense being issued.
The constraint of no pre-license construction resulted in the
elimination of any plan in which initial access could not be
comp1eted within one year.This constraint led to the elimina-
tion of the access plan submitted in the Susitna Hydroe1ectric
Project Feasibility Report (Plan 5)and five other plans (2,8,
9,10,and 12).
E-10-37
2.3 -Access Alternatives
Upon completion of both the Watana and Devil Canyon dams,it is
planned to operate and maintain both sites from one central loca-
tion (Watana).To facilitate these operation and maintenance
activities,access plans with a road connection between the sites
were considered superior to those pl ans without a road connec-
t ion.Pl ans 3 and 4 do not have access between the sites and
were discarded.
The abil ity to make full use of both rail and road systems from
southcentral ports of entry to the railhead facility provides the
project management with far greater fl exi bi 1 ity to meet cont i n-
gencies,and control costs and schedule.Limited access plans
utilizing an all rail or rail link system with no road connection
to an existing highway have less fleixibility and-would impose a
restraint on project operation that could result in delays and
significant increases in cost.Four plans with limited access
(Plans 8,9,10 and 15)were eliminated because of this con-
stra i nt.
Residents of the Indian River and Gold Creek corrrnunities are
generally not in favor of a road access near their communities.
Plan 1 was discarded because Plans 13 and 14 achieve the same
objecti ves without impacti ng the Indi an Ri ver and Gol d Creek
areas.
Plan 7 was eliminated because it includes a circuit route connec-
ting to both the George Parks and Denali Highways.This circuit
route was considered unacceptable by the resource agencies since
it aggravated the control of public access.
The seven remaining plans found to meet the selection criterion
were Plans 6,11,13,14, 16,17 and 18.Of these,Plans 13, 16,
and 18 in the North,South,and Denali corridors,respectively,
were selected as being the most responsive plan in each corridor.
The three plans are described below.
2.3.5 -Description of Most Responsive Access Plans
(a)Plan 13 "North"(see Figure L10.7)
This plan utilizes a roadway from a railhead facility adja-
cent to the George Parks Highway at Hurricane to the Watana
damsite following the north side of the Susitna River.A
spu r road seven mi 1es in 1ength woul d be constructed at a
later date to service the Devil Canyon development.Travel-
1 ing soutrreast from Hurricane,the route passes through
Chul itna Pass,avoids the Indian River and Gold Creek areas,
then parallels Portage Creek at a high elevation on the
north side.After crossing Portage Creek the road continues
at a high elevation to the Watana damsite.Access to the
E-10-38
('-
"...,
2.3 -Access Alternatives
(b)
(c)
south side of the Susitna Ri ver at the Devil Canyon damsite
would be attained via a high level suspension bridge approx-
imately one mile downstream from the Devil Canyon dam.This
route crosses mountainous terrain at high elevations and
includes extensive sidehill cutting in the region of Portage
Creek.Construction of the road,however,would not be as
difficult as Plan 16,the South route.
Plan 16 ~South (see Figure E.ID.8)
This route generally parallels the Susitna River,traversing
west to east from a ra il head at Gol d Creek to the Devil
Canyon damsite,and continues following a southerly loop to
the Watana damsite.To achieve initial access within one
year,a temporary low level crossing to the north side of
the Susitna River is required approximately twelve miles
downstream from the Watana damsite.This would be used
until completion of a permanent high level bridge.In addi-
tion,a connecting road from the George Parks Highway to
Devil Canyon,with a major high level bridge across the
Susitna Ri ver,is necessary to provide full road access to
either site.The topography from Devil Canyon to Watana is
mountainous and the route involves the most difficult con-
struction of the three plans~requiring a number of sidehill
cuts and the construction of two major bridges.To provide
initial access to the Watana da!T1site,this route presents
the most difficult construction problems of the three
routes,and has the highest potential for schedule delays
and related cost increases.
Plan 18 ~Denali-North~(see Figure LID.9)
This route originates at a railhead in Cantwell,and then
follows the existing Denali Highway to a point 21 miles east
of the junction of the George Parks and Denali highways.A
new road would be constructed from this point due south to
the Watana damsite.The majority of the new road would
traverse relatively flat terrain which would allow construc-
tion using side borrow techniques,resulting in a minimum of
disturbance to areas Qway from the alignment.This is the
most easi ly constructed route for initial access to the
Watana site.Access to the Devil Canyon developnent woul d
consist primarily of a railroad extension from the existing
Alaska Railroad at Gold Creek to a railhead facility adja-
cent to the Devi 1 Canyon camp area.To provide access to
the Watana damsite and the existing highway system,a con-
necting road would be constructed from the Devil Canyon
rail head following a northerly loop to the Watana damsite.
E-I0-39
2.3 -Access Alternatives
Access to the north side of the Susitna River would be
attained via a high level suspension bridge constructed
approximately one mile downstream from the Devil Canyon dam.
In general,the alignment crosses terrain with gentle to
moderate slopes which would allow roadbed construction with-
out deep cuts.
2.3.6 -Comparison of the Selected Alternative Plans
To determi ne which of the three access pl ans best accommodated
both project related goals and the concerns of the resource agen-
cies,Native organizations,and affected communities,the plans
were subjected to a multi-disciplinary evaluation and comparison.
Among the issues addressed in this evaluation and comparison
we re:
-Costs;
-Schedule;
Environmental issues;
-Cultu ral resources;
-Socioeconomics/Community preferences;
-Preferences of Native organizations;
-Relationship to current land stewardships,uses and plans;and
-Recreation.
(a)Costs
The relative cost of the three access alternatives is pre-
sented below.Thi s outl i nes the total costs of the three
plans with the schedule constraint that initial access must
be completed within one year of receipt of the FERC license.
Costs to complete the access requi rement for the Watana
development only are also shown.The costs of the three
alternative plans can be summarized as follows:
Estimated Total Cost ($x 10 6 )
Devil Discounted
p-
Plan Watana Canyon Total Total
North (13)241 127 368 287
South (16)312 104 416 335
De na 1 i-North (18)224 213 437 326
The costs are in terms of 1982 dollars and include all costs
associated with design,construction,maintenance,and
1 ogi st i cs.Di scounted total costs (present worth as of
1982)have been shown here for comparison purposes to deli-
neate the differences in timing of expenditure.
E-1O-40
-.
.-
I""'"!
2.3 -Access Alternatives
For the development of access to the Watana site,the
Denali-North Plan has the least cost and the lowest proba-
bil ity of increased costs resulting from unforeseen condi-
t ions.The No rth Pl an is ranked second.The North Pl an has
the lowest overall cost while the Denali-North has the high-
est.However,a 1 arge portion of the cost of the Denal i-
North Pl an woul d be incurred more than a decade in the
future.When converting costs to equivalent present value,
the overall costs of the Denali-North and the South plans
a re si mila r.
-
-
(b)Schedule
The schedule for providing initial access to the Watana site
was given prime consideration since the cost ramifications
of a schedule delay are highly significant.The elimination
of pre-license construction of a pioneer access road has
resulted in the severe compression of on-site construction
activities in the 1985-86 period.With the present overall
project scheduling,should diversion not be completed prior
to spring runoff in 1987,dam foundation preparation work
would be delayed one year,and hence cause a delay to the
overall project of one year.It has been estimated that the
resultant increase in cost would likely be in the range of
100-200 million dollars.The access route that assures the
quickest completion and hence the earl iest del ivery of
equipment and materials to the site has a distinct advan-
tage.The forecasted construction period for initial
access,including mobilization,for the three plans are:
It is evident that with the Denali-North Plan site activi-
ties can be supported at an earlier date than by either of
the other routes.Consequently,the Denali-North ~an
offers the highest probability of meeting schedule and hence
the least risk of project delay and increase in cost.
-!
Denal i-North
North
South
6 months
9 months
12 months
-
(c)·Environmental Issues
Environmental issues have played a major role in access
planning to date.The main issue is that a road will permit
human entry into an area which is relatively inaccessible at
Rresent,causing both direct and indirect impacts.A sum-
mary of these key impacts with regard to wil dl ife,wi 1dl i fe
habitat,and fisheries for each of the three alternative
access plans is outlined below.
E-10-41
2.3 -Access Alternatives
(d)Wildlife and Habitat
The three selected alternative access routes are made up of
five distinct wildlife and habitat segments:
(i)Hurricane to Devil Canyon
This segment is composed almost entirely of produc-
tive mixed forest,riparian,and wetlands habitats
important to moose,furbearers,and birds.It
includes three areas where slopes of over 30 percent
will require side-hill cuts.a11 above wetland zones
vulnerable to erosion related impacts.
(ii)Gold Creek -to Devil Canyon
This segment is composed of mixed forest and wetland
habitats,but includes less wetland habitat and fewer
wetland habitat types than the Hurricane to Devil
Canyon segment.Although this segment contains habi-
tat suitable for moose,black bears,furbearers and
birds,it has the least potential for adverse impacts
to wildl ife of the five segments considered.
(iii)Devil Canyon to Watana (North Side)
The following comments apply to both the Denali-North
and North routes.This segment traverses a varied
mixture of forest,shrub,and tundra habitat types,
generally of medi um to low producti vity as wil dl i fe
habitat.It crosses the Devil and Tsusena Creek
drai nages and passes by Swimmi ng Bear Lake,whi ch
contains habitat suitable for furbearers.
(iv)Devil Canyon to Watana (South Side)
This segment is highly varied with respect to habitat
types.containing complex mixtures of forest,shrub,
tundra,wetlands,and riparian vegetation.The
western portion is mostly tundra and shrub.with
forest and wetlands occurring along the eastern por-
tion in the 'vicinity of Prairie Creek,Stephan Lake,
and Tsusena and Deadman Creeks.Prai rie Creek sup-
ports a high concentration of brown bears and the
lower Tsusena and Deadman Creek areas support lightly
hunted concentrations of moose and bl ack bears.The
Stephan Lake area supports high densities of moose
and bears.Access development in this segment would
probably result in habitat loss or alteration,
increased hunting,and human-bear conflicts.
2.3 -Access Alternatives
(v)Denali Highway to Watana
Thi s segment is primarily composed of shrub and
tundra vegetation types,with little productive
forest habitat present.Although habitat diversity
is relatively low along this segment,the southern
portion along Deadman Creek contai ns an important
brown bear concentration and browse for moose.This
segment crosses a peripheral portion of the range of
the Nelchina caribou herd and there is evidence that
as herd size increases,caribou are likely to migrate
across the route and calve in the vicinity.Although
it is not possible to predict with any certainty how
the physical presence of the road itself or traffic
will affect caribou movements,population size,or
productivity,'it is 1 ikely that a variety of site-
specific mitigation measures will be necessary to
protect the herd.
The three access plans are made up of the following
combinations of route segments:
North
South
Denali-North
Segments 1 and 3
Segments 1,2,and 4
Segments 2,3,and 5
-
-
(e)
The North plan has the least potential for creating
adverse impacts to wil dlife and habitat,since it
traverses or approaches the fewest areas of produc-
t i ve habitat a nd zones of speci es concentrat i on or
movement.The wildlife impacts of the South Plan can
be expected to be greater than those of the North
Plan due to the proximity of the route to Prai rie
Creek,Stephan Lake and the Fog Lakes,which cur-
rently support high densities of mOOse and black and
brown bears.In particular Prairie Creek supports
what may be the highest concentration of brown be.ars
in the Susitna Basin.Although the Denali-North Plan
has the potential for disturbances of caribou,brown
bear and bl ack bear concentrat ions,and movement
zones,it is considered that the potential for
adverse impacts with the South Plan is greater.
Fisheries
All three alternative routes would have direct and indirect
impacts on the fisheries.Direct impacts include the
effects on water quality and aquatic habitat whereas
increased angling pressure is an indirect impact.A quali-
tat i ve compari son of the fi shery impacts rel ated to the
2.3 -Access Alternatives
alternative plans was undertaken.The parameters used to
assess impacts along each route included the number of
streams crossed,the number and 1ength of 1ateral trans its
(i.e.,where the roadway parallels the streams and runoff
from the roadway can run di rectly into the stream),the
number of watersheds affected,and the presence of resident
and anadromous fish.
The three access plan alternatives incorporate combinations
of seven distinct fishery segments.
(i)Hurricane to Devil Canyon
Seven stream crossings will be required along this
route,including Indian River which is an important
salmon spawni ng ri ver.Both the Chul itna Ri ver
watershed and the Susitna River watershed are affec-
ted by this route.The increased access to Indian
River will be an important indirect impact to the
segment.
Approximately 1.8 (2.9 km)miles of cuts into banks
greater than 30 degrees occur along this route,
requiring erosion control measures to preserve the
water quality and aquatic habitat.
(ii)Gold Creek to Devil Canyon
Th is segment c ros ses six st reams and is expected to
have minimal direct and indirect impacts.Anadromous
fish spawning is likely in some streams but impacts
are expected to be mi nimal.Approximately 2.5 mil es
(4 km)of cuts into banks greater than 30 degrees
occur in this section.In the Denali-North Plan this
segment would be railroad,whereas in the South Plan
it would be road.
(iii)Devil Canyon to Watana (North Side,North Plan)
This segment crosses 20 streams and laterally
transits four rivers for a total distance of approxi-
mately 12 miles (20 km).Seven mi les (11 km)of this
lateral transit parallels Portage Creek,which is an
important salmon spawning area.
(iv)Devil Canyon to Watana (North Side,
Denali-North Plan
The difference between this segment and Segment iii
descri bed above is that it avoi ds Portage Creek by
traversing through a pass 4 miles (6 km)to the east.
E-10-44
2.3 -Access Alternatives
The number of streams crossed is consequently reduced
to 12,and the number of 1ateral transits is reduced
to two,with a total distance of 4 miles (6 km).
(v)Devil Canyon to Watana (South Side)
The porti on between the Susitna Ri ver crossi ng and
Devil Canyon requires nine steam crossings,but it is
unlikely that these contain significant fish popula-
tions.The portion of this segment from Watana to
the Susitna River is not expected to have any major
direct impacts;however,increased angling pressure
in the vicinity of Stephan Lake may result due to the
proximity of the access road.The segment crosses
both the Susitna and the Ta 1keetna watershed.Seven
mil es (11 km)of cuts -j nto banks of greater than 30
degrees occur in this segment.
(vi)Denali Highway to Watana
The segment from the Denal i Hi ghway to the Watana
damsite has 22 stream crossings and passes from the
Nenana into the Sus itna watershed.Much of the route
~crosses or is in proximity to seasonal grayling habi-
tat and runs parallel to Deadman Creek for nearly 10
mi 1es (16 km).If recruitment and growth rates are
low along this segment it is unlikely that resident
populations could sustain heavy fishing pressure.
Hence,this segment has a high potential for impact-
ing the local grayling population.
(vii)Denali Highway
The Denali Highway from Cantwell to the Watana access
turnoff will require upgrading.The upgrading will
involve only minor realignment and negligible altera-
tion to present stream crossings.The segment
crosses 11 streams and 1 aterally transits two rivers
for a total distance of 5 miles (8 km).There is no
anadromous fish spawning in this segment and little
~direct or indirect impact is expected.
The three alternative access routes are comp ri sed of the
following segments:
North Segments 1 and 3
South Segment s 1,2,and 5
I"'"Denal i-North segments 2,4,6 and 7
-
E-IO-45
2.3 -Access Alternatives
The Denali-North Plan is likely to have a significant direct
and indirect impact on grayling fisheries given the number
of stream crossings,1ateral transits,and watersheds
affected.Anadromous fisheries impact will be minimal and
will only be significant along the railroad spur between
Gold Creek and Devil Canyon.
The South Plan is likely to create significant direct and
indirect impacts at Indian River,which is an important
salmon spawning river.Anadromous fisheries'impacts will
al so occur in the Gold Creek to Dev"il Canyon segment as for
the Denali-North Plan.In addition indirect impacts may
occur in the Stephan Lake area.
The North Plan,like the South Plan,may impact salmon
spawning activity in Indian River.Significant impacts are
1i kely along Portage Creek due to water qual ity impacts
through increased erosi on and due to i ndi rect impacts such
as increased angling pressure.
With any of the selected plans,direct and indirect effects
can be minimized through proper engineering design and
prudent management.Criteri a for the development of borrow
sites and the design of bridges and culverts for the pro-
posed access plan together with mitigation recommendations
are discussed in Chapter 3 of Exhibit E.
(f)Cultural Resources
A 1evel one cul tural resources survey was conducted over a
large portion of the three access plans.The segment of the
Denali-North Plan between the Watana damsite and the Denali
Highway traverses an area of high potential for cultural
resource sites.Treeless areas along this segment lack
appreciable soil desposition.making cultural resources
visible and more vulnerable to secondary impacts.Common to
both the Denali-North and the North Plan is the segment on
the north side of the Susitna River from the Watana damsite
to where the road parallels Devils Creek.This segment is
also largely treeless,making it highly vulnerable to secon-
dary impacts.The South Plan traverses less terrain of
archaeological importance than either of the other two
routes.Several sites exist along the southerly Devil
Canyon to Watana segment;however.si nce much of the route
is forested,these sites are 1 ess vulnerable to secondary
impacts.
The ranki ng from the 1east to the hi ghest wi th regard to
cultural resource impacts is South,North,Denali-North.
E-10-46
2.3 -Access Alternatives
However,impacts to cultural resources can be fully mitiga-
ted by avoidance,protection or salvage;consequently,this
issue was not critical to the selection process.
(g)Socioeconomics/Community Preferences
Socioeconomic impacts on the Mat-su Borough as a whole would
be similar in magnitude for all three plans.However,each
of the three plans affects future socioeconomic conditions
in differing degrees in certain areas and communities.The
important differences affecting ~pecific communities are
outlined below.
(i)Cantwell
.-The Denali-North Plan would create significant in-
creases in population,local employment,business
activity,housing and traffic.These impacts result
because a railhead facility would be located at
Cantwell and because Cantwell woul d be the nearest
community to the Watana damsi teo Both the North and
South Plans would impact Cantwell to a far lesser
extent.
,....,
(i i)Hurri cane
The North Plan would significantly impact the Hurri-
cane area,since currently there is little popula-
tion,employment,business activity or housing.
Changes in socioeconomic indicators for Hurricane
would be less under the South Plan and considerably
less under the Denali-North plan.
-
(iii)
(i v)
Trapper Creek and Talkeetna
Trapper Creek woul d experi ence sl i ghtly 1a rger
changes in economic indicators with the North plan
than under the South or Denali-North Plans.The
South Plan would impact the Talkeetna area slightly
more than the other two plans.'
Gol d Creek
With the South Plan,a rai"lhead facility would be
developed at Gold Creek creating a significant in-
crease in socioeconomic indicators in this area.The
Denali-North Plan includes construction of a railhead
facility at the Devil Canyon site which would create
impacts at Gold Creek,but not to the same extent as
the South Plan.Minimal impacts would result in Gold
Creek under the North Plan.
E-10-47
2.3 -Access Alternatives
The responses of people who wi 11 be affected by these poten-
tial changes are mixed.The people of Cantwell are
generally in favor of some economic stimulus and development
in thei r communi ty.Some concern was expressed over the
potential effects of access on fish and wildlife resources,
but with stringent hunting regulations implemented and
enforced,it was considered that this problem could be suc-
cessfully mitigated.The majority of residents in both
Talketna and Trapper Creek have indicated a strong prefer-
ence to maintain their general lifestyle patterns and do not
desire rapid,uncontrolled change.The Denali-North Plan
would impact these areas the least.The majority of land-
holders in the Indian River subdivision favor retention of
the remote status of the area and do not want road access
through thei r 1 ands.This and other feedback to date
indicate that the Denal i-North Plan will come closest to
creating soci oeconomic changes that are acceptable to or
desired by landholders and residents in the potentially
impacted areas and communities.
(h)Preferences of Native Organizations
Cook Inlet Region Inc.(CIRI)has selected lands surrounding
the impoundment areas and south of the Susitna River between
the damsites.CIRI has offici ally expressed a preference
for a plan providing road access from the George Parks High-
way to both damsites along the south side of the Susitna
River.The Tyonek Native Corporation and the CIRI village
residents have indicated a similar preference.The South
Pl an provides full road access to thei r 1 ands south of the
Sutina River and thus comes closest to meeting these
desires.The AHTNA Native Region Corporation presently owns
land bordering the Denali Highway and they,together with
the Cantwell Village Corporation,have expressed a prefer-
ence for the Denal i-North Plan.None of the Native organi-
zations support the North Plan.
(i)Relationship to Curreilt Land Stewardships,Uses and Plans
Much of land required for project development has been or
may be conveyed to Native organizations.The remaining
lands are generally under state and federal control.The
South Plan traverses more Native-selected lands than either
of the other two routes,and although present land use is
low,the Native organizations have expressed an interest in
potentially developing their lands for mining,recreation,
forestry,or residential use.
The other land management pl ans that have a large bearing on
access developrnent are the Bureau of Land Management's (BLM)
E-10-48
-
-
2.3 -Access Alternatives
recent decision to open the Denali Planning Block to mineral
exploration,and the Denali Scenic Highway Study being
i niti ated by the Al aska Land Use Council.The Denal i Hi gh-
way to Deadman Mountai n segment of the Denal i-North Pl an
would be compatible with BLM's plans.During the construc-
tion phase of the project,the Denali'-North Plan could
create confl i cts with the development of a Denal i Sceni c
Highway;however,after construction,the access road and
project facil ities could be incorporated into the overall
scenic highway planning.
By providing public access to a now relatively inaccessible,
semi-wilderness area,conflict may be imposed with wildlife
habitats necessitating an increased level of wildlife and
people management by the various resource agencies.
In general,however,none of the plans will be in major con-
flict with any present federal,borough,or Native manage-
ment plans.
(j)Recreation
Following meetings,discussions,and evaluation of various
access plans,it became evident that recreation plans are
flexible enough to adapt to any of the three selected access
routes.No one route was identified which had superior
recreational potential associated with it.Therefore,com-
patibility with recreational aspects was essentially elimin-
ated as an evaluation criterion.
2.3.7 -Summary of Final Selection of Plans
In reaching the decision as to which of the three alternative
access plans was to be recommended,it was necessary to evaluate
the highly complex interplay that exists between the many issues
involved.Analysis of the key issues described in the preceeding
pages indicates that no one plan satisfied all the selection
criteria nor accommodated all the concerns of the resource agen-
cies,Native organizations and public.Therefore,it was neces-
sary to make a rational assessment of tradeoffs between the some-
times conflicting environmental concerns of impacts on fisheries,
wildlife,socioeconomics,land use,and recreational opportun-
ities on the one hand,with project cost,schedule,construction
risk and management needs on the other.With all these factors in
mi nd,it shoul d be emphasi zed that the primary purpose of access
is to provide and maintain an uninterrupted flow of materials and
personnel to the damsite throughout the 1 ife of the project.
Should this fundamental objective not be achieved,significant
schedule and budget overruns will occur.
E-1O-49
2.3 -Access Alternatives
(a)Elim"ination of "South Plan"
The South route,Plan 16,was el iminated primarily because
of the construction difficulties associated with building a
major low level crossing 12 miles (20 km)downstream from
the Watana damsite.This crossing would consist of a float-
ing or fixed temporary bridge which would need to be removed
prior to spring breakup during the first three years of the
project (the time estimated for completion of the permanent
bridge).This would result in a serious interruption in the
flow of materials to the site.Another drawback is that
floating bridges require continual maintenance and are
generally subject to more weight and dimensional limitations
than permanent structures.
A further limitation of this route is that,for the first
three years of the project,all construction work must be
supported solely from the railhead facility at Gold Creek.
This problem arises because it will take an estimated three
years to complete construction of the connecting road across
the Susitna River at Devil Canyon to Hurricane on the George
Parks Highway.Limited access such as this does not provide
the flex"ibi 1ity needed by the project management to meet
contingencies and control costs and schedule.
Delays in the supply of materials to the damsite,caused by
either an interruption of service of the railway system or
the Susitna River not being passable during spring breakup,
could result in significant cost impacts.These factors,
together with the realization that the South Plan offers no
specific advantages over the other two plans in any of the
areas of envi ronmental or soci al concern,1ed to the South
Plan being eliminated from further consideration.
(b)Schedule Constraints
The choice of an access plan thus narrowed down to the North
and Denali-North Plans.Of the many issues addressed during
the evaluation process,the issue of "schedule"and "sched-
ule risk"was determined as being the most important in the
final selection of the recommended plan.
Schedule plays such an important role in the evaluation pro-
cess because of the special set of conditions that exist in
a subarctic environment.Building roads in these regions
involves the consideration of many factors not found else-
where in other environments.Specifically,the chief con-
cern is one of weather and the consequent short duration of
the constructi on season.The roads for both the No rth and
E-10-50
-
2.3 -Access Alternatives
Denali-North plans will,for the most part,be constructed
at elevations in excess of 3000 feet (900 m).At these
elevations,the likely time available for uninterrupted
construction in a typical year is 5 months,and at most 6
months.
The forecasted construction period,for initial access
including mobilization,is 6 months for the Denali-North and
9 months for the North.At first glance,a difference in
schedule of 3 months does not seem great;however,when con-
sidering that only 6 months of the year are available for
construction,the additional 3 months become highly signifi-
cant,especially when read in the context of the 1 ikely
schedule for issuance of the FERC 1 icense.
The date the FERC license will be issued cannot be
accurately determined at this time,but is forecast to be
within the first nine months of 1985.Hence,the interval
between licensing and the scheduled date of diversion can
vary significantly.This illustrates that the precise time
of year the 1 icense is issued is critical to the construc-
tion schedule of the access route;for if delays in licen-
sing occur,there is a risk of delay to the project schedule
to the extent that river diversion in 1987 will be missed.
The risk of delays increases:
The later the FERC license is issued;and
-The longer the schedule required for construction of
initial access.
If diversion is not achieved prior to spring runoff in 1987,
dam foundation preparation work will be delayed one year,
and hence,cause a delay to the overall project of one
year.
r
I
(c)
(d)
Cost Impacts.
The increase in costs resulting from a one year delay have
been estimated to be in the range of 100-200 million dol-
lars.This increase includes the financial cost of invest-
ment by spring of 1987,the financial costs of rescheduling
work fora one year delay,and replacement power costs.
Concl usi on
The Denali-North Plan has the highest probability of meeting
schedule and least risk of increase in project cost for two
reasons.Fi rst,it has the shortest construction schedule
(six months).Second,a possible route could be constructed
even under wi nter conditi on,owing to the rel at ive f1 at
E-1O-51
2.3 -Access Alternatives
terrain along its length.In contrast,the North route is
mountainous and involves extensive sidehill cutting,es-
pecially in the Portage Creek area.Winter construction
along sections such as this would present major problems and
increase the probability of schedule delay.
2.3.8 -Modifications to Recommended Access Plan
Following approval of the recommended plan by the Alaska Power
Authority Board of Directors in September 1982,further studies
were conducted to optimize the route location,both in terms of
cost and minimizing impacts to the environment.Each of the
specialist subconsultants was asked to review the proposed plan
to identify specific problem areas,develop modifications and
improvements,and contribute to drawi ng up a set of general
guidelines for access development.The results of this review
are capsulized below.
-An important red fox denning area and a bald eagle nest were
identified close to the proposed road alignment,so conse-
quent ly the road was real i gned to create a buffer zone of at
least one half mile between the road and the sites.
-Portions of the access road between the Denali Highway and the
Watana damsite will traverse flat terrain.In these areas,a
berm type cross section wi 11 be formed with the crown of the
road being 2 to 3 feet (0.6 to 0.9 m)above the elevation of
adjacent ground.Steep side slopes woul d present an unnatural
barrier to migrating caribou,exaggerate the visual impact of
the road itself,and aggravate the problem of snow removal.To
reduce these problems,the side slopes will be flattened using
excavated peat material and rehabilitated through scarification
and fertilization.
-The chief fisheries concern was the proximity of the proposed
route to Deadman Creek,Deadman Lake,and Big Lake.For a
distance of approximately 16 mil es (26 km)the road parallel s
Deadman Creek,which contains good to excellent grayling popu-
lations.To alleviate the problem of potential increased
angling pressure,the road was moved one half to one mile west
of Deadman Creek.The road was moved even fu rther to the west
of Deadman and Big Lakes,which contain both grayling and lake
trout,for the same reason.
-The prel iminary,reconniassance level cultural resource survey
conducted on the proposed access route located and documented
24 sites on or in close proximity to the right-of-way and/or
potential borrow sites.The number of these sites that will be
directly or indirectly affected will not be known until a more
E-10-52
2.3 -Access Alternatives
detailed investigation is completed.However,indications are
that all sites can be mitigated by avoidance,protection,or
salvage.
-The community that will undergo the most growth and socio-
economic change with the proposed access pl an is Cantwell.
Subsequent to the selection of this access plan,the residents
of Cantwell were solicited for their comments and suggestions.
Their responses resulted in the following modifications and
recommendations:
The pl an was modified to i ncl ude pavi ng the road from the
railhead facility to four miles east of the junction of the
George Parks and Denali Highways.This will eliminate any
problem with dust and flying stones in the residential
district.
For safety reasons,it is recommended that:
Speed restrictions be imposed along the above segment;
A bike path be provided along the same segment because of
the proximity of the local school;and
Improvements be made to the intersection of the George
Parks Highways including pavement markings and traffic
signals.
-The main concern of the Native organizations represented by
CIRI is to gai n access to thei r 1 and south of the Su sitna
River.Under the proposed access plan,these lands will be
accessible by both road and rail,the railroad being from Gold
Creek to the Devil Canyon damsite on the south side of the
Susitna Ri ver.After completion of the Watana dam,road
access will be provided across the top of the dam to Native
lands.Similarly,a road across the top of the Devil Canyon
dam will be constructed once themai n works at Devi 1 Canyon
are completed.In addition,alternative road access will be
available via·the high level suspension bridge one mile
downstream from the Devil Canyon dam.
From an environmental standpoint,iti s desi rabl e to 1 imit the
number of people in the project area in order to minimize
impacts to wildlife habitat and fisheries.An unpaved road
with 1 imited access would reduce these impacts and serve to
maintain as much as possible the wilderness character of the
area.An evaluation of projected traffic volumes and loadings
confi rmed that an unpaved gravel road with a 24 ft (7.2 m)
running surface and 5 ft (1.5 m)wide shoulder would be
adequate.
E-IO-53
2.4 -Transmission Alternatives
For the efficient,economical,and safe movement of supplies,
the following design parameters were chosen:
~'\
•Maximum grade
•Maximum curvature
•Design loading:
••during construction
••after construction
6 percent
5 degrees
SOk axle,200 k total
HS-20
Adhering to these grades and curvatures,the entire length of the
road would result in excessively deep cuts and extensive fills in
some areas,and could create serious technical and environmental
problems.From an engineering standpoint,it is advisable to
avoid deep cuts because of the potential slope stability prob-
1 ems,especially in permafrost lones.Al so,deep cuts and 1arge
fills are detrimental to the environment for they act as a bar-
rier to the migration of big game and disrupt the visual harmony
of the wilderness setting.Therefore,in areas where adhering to
the aforementioned grades and curvatures involve extensive cutt-
ing and filling,the design standards will be reduced to allow
steeper grades and shorter radius turns.
This flexibility of design standards provides greater latitude to
"fit"the road within the topography and thereby enhance the vis-
ual quality of the surrounding landscape.For reasons of driver
safety,the design standards will in no instance be less than
those applicable to a 40 mph (65 kmh)design speed.
2.4 -Transmission Alternatives
2.4.1 -Corridor Selection Methodology
Development of the proposed Susitna project will require a trans-
mission system to deliver electric power to the Railbelt area.
The building of the Anchorage-Fairbanks Intertie System will re-
sult in a corridor and route for the Susitna transmission lines
between Willow and Healy.Three areas have been studied for cor-
ridor selection:the northern area connecting Healy with Fair-
banks;the central area connecting the Watana and Devil Canyon
dams ites with the Interti e;a nd the southern a rea connecting
Wi llow with Anchorage.
Using the selection criteria for economic,technical,and en-
vironmental considerations discussed in Exhibit B,Section 2.7
(b),corridors 3 to 5 miles (5 to S km)wide were selected in
each of the three study areas.These corridors were then evalua-
ted to determine which ones met the more specific screening cri-
teria (Exhibit B,Section 2.7[c]and below).This screening pro-
cess resul ted in one corridor in each area bei ng des i gnated as
the recommended corridor for the transmission line.The environ-
mental selection and screening processes are described below.
E-10-54
r
!
2.4 -Transmission Alternatives
2.4.2 -Environmental Selection Criteria
The environmental criteria used in selection of the candidate
corridors are listed below~
",..,
Primary
Secondary
Criteria
Devel opm~nt
Existing Transmission
Ri ght-of-Way
Land Status
Topography
Vegetation
Selection
Avoid existing or
proposed developed
areas.
Parallel where
poss i bl e.
Avoid private lands,
wildlife refuges,parks.
Select gentle relief
where possible.
Avoid heavily timbered
areas.
Since the corridors that were studied range in width from three
to five miles,the base criteria had to be applied to broad
areas.Some of the criteria used in the environmental selection
process were also pertinent to the technical and economical
analysis.For example,it is economically advantageous to avoid
high right-of-way costs in developed areas;and gentle topography
enhances technical reliability through ease of access.
2.4.3 -Identification of Corridors
The Susitna transmission line corridors that were selected for
further screening are located in three geographical areas:
-The so uthern St udy area between Willow and An chorage(to ca rry
Susitna power into Anchorage);
-The central study area between Watana,Devil Canyon,and the
Intertie (to carry Susitna power to the Intertie right-of-way);
and
-The northern study area between Healy and Fai rbanks (to carry
Susitna power into Fairbanks).
Twenty-two corridors were selected and are shown in Figures
E.10.10,E.10.11,and E.10.12.
E-10-55
2.4 -Transmission Alternatives
2.4.4 -Environmental Screening Criteria
Because of the potential,adverse environmental impacts from
transmission line construction and operation,environmental
criteria were carefully scrutinized in the screening process.
Past experience has shown the primary envi ronmental
considerations to be:
-Aesthetic and Visual (including impacts to recreation);and
-Land Use (including ownership and presence of existing
rights-of-way).
Also of significance in the evaluation process are:
-Length;
-Topog raphy;
-So i 1s ;
-Cultural Resources;
-Vegetation;
-Fishery Resources;and
-Wildlife Resources.
(a)Primary Aspects:
(i)Aesthetic and Visual
The presence of large transmission line structures in
undeveloped areas has the potential for adverse aes-
thetic impacts.Furthermore,the presence of these
lines can conflict with recreational use,particularly
those nonconsumptive recreational activities such as
hiking and bird watching where great emphasis is
placed on scenic values.The number of road crossings
encountered by t ransmi ss ion 1i ne corri dors is also a
factor that needs to be i nventori ed because of the
potential for visual impacts.The number of roads
crossed,the manner in which they are crossed,the
nature of existing vegetation at the crossing site
(i.e.,potential visual screening),and the number and
type of motorists using the highway all influence the
desi rabil ity of one corridor versus another.There-
fore,when screeni n-g the previously sel ected corri-
dors'consideration was focused on the presence of
recreational areas,hiking trails,heavily utilized
lakes,vistas,and highways where views of transmis-
sion line facilities would be undesirable.
E-10-56
""'"I
....
r
2.4 -Transmission Alternatives
(ii)Land Use
The three primary components of 1and use consi dera-
tions are:1)land status/ownership,2)existing
rights-of-way,and 3)existing and proposed develop-
ment.
-Land/Status/Ownership
The ownership of land to be crossed by a transmis-
s ion 1i ne is important because certain types of
ownership present more restrictions than others.
For example,some recreation areas such as state and
federa 1 parks,game refuges,and mil ita ry 1 ands,
among others,present possible constraints to corri-
dor routing.Private landowners generally do not
want transmission lines on their lands.This infor-
mation,when known in advance,permits corridor
routing to avoid such restrictive areas and to occur
in areas where land use conflicts can be minimized.
-Existing Rights-of-Way
Paralleling existing rights-of-way tends to result
in less environmental impact than that which is
associated with a new right-of-way because the crea-
tion of a new right-of-way may provide a means of
access to areas normally accessibl e only on foot •
This can be a critical factor if it opens sensitive,
ecological areas to all-terrain vehicles.
Impact on soils,vegetation,stream crossings,and
others of the inventory categories can also be
lessened through the paralleling of existing access
roads and cleared rights-of-way.Some impact is
st ill felt,however,even though a ri ght-of-way may
exist in the area.For example,cultural resources
may not have been identified in the original routing
effort.Wetlands present under existing transmi s-
sion lines may likewise be negatively influenced
since ground access to the vicinity of the tower
locations is requi red.
There are common occasions where paralleling an
existing facility is not desirable.This is parti-
cularly true in the case of highways that offer the
potential for visual impacts and in situations where
paralleling a poorly sited transmission facility
would only compound an existing problem.
E-lO-57
2.4 -Transmission Alternatives
-Existing and Proposed Developments
Thi s inventory i dent ifies such thi ngs as agri cul-
tural use;planned urban developments;existing
residential and cabin develop11ents;the location of
ai rports and of 1akes used for floatpl anes;and
similar types of information.Such information is
essential for locating transmission line corridors
appropriately,since it prevents conflicts with
these land use activities.
(b)Secondary Aspects:
(i)Length
The length of a transmission line is an environmental
factor and,as such,was considered in the screening
process.A longer 1i ne wi 11 requi re more construc-
ti on activity than a shorter 1 ine,will disturb more
land area,and will have a greater inherent probabil-
ity of encountering environmental constraints.
(ii)Topography
The natural features of the terrain are significant
from the standpoint that they offer both positive and
negative aspects to transmission line routing.Steep
slopes,for example,present both difficult construc-
tion and soil stabilization problems with potentially
long-term,negative environmental consequences.
Al so,ridge crossings have the potential for visual
impacts.At the same time,slopes and elevation
changes present opportunities for routing trans-
mission lines so as to screen them from both travel
routes and existing communities.Therefore,when
planning corridors the identification of changes in
relief is an important factor.
(i ii )So il s
Soils are important from several standpoints.First
of all,scarification of the land often occurs during
the construction of transmission lines.As a result,
vegetation regeneration is affected,as are the rela-
ted features of soil stability and erosion potential.
In addition,the development and installation of
access roads,where necessa ry,a re very dependent
upon soil types.Tower designs and locations are
di ctated by t he types of soil s encountered in any
-
2.4-Transmission Alternatives
parti cul ar corridor segment.Consequently,the
review of existing soils information is very signifi-
cant.
~,
(iv)
(v)
(vi)
Cultural Resources
The avoidance of known or potential sites of cultural
resources is an important component of the routing of
transmission lines.A level one cultural resources
survey has been conducted along a 1arge port i on of
the transmission corridors.In those areas where no
information has been collected to date,an appropri-
ate program for identifying and mitigating impacts
will be conducted.This program is discussed in more
detail in Chapter 4 of Exhibit E.
Vegetation
The consideration of the presence and location of
various plant communities is essential in transmis-
sion line siting.The inventory of plant communi-
ties,such as those of a tall-growing nature or wet-
lands,is significant from the standpoint of con-
struction,clearing,and access road development
requirements.In addition,identification of loca-
tions of endangered and threatened plant species
is also critical.While several Alaskan plant
species are currently under review by the U.S.Fish
and Wildlife Service,none are presently listed under
the Endangered Species Act of 1973.No corridor
-traverses any 1ocat i on known to support these i dent i-
fied plant species.
Fishery Resources
The presence or absence of resident or anadromous
fish in a stream is a significant factor in evaluat-
ing suitable transmission line corridors.The corri-
doris effects on a streamls resources must be viewed
from the standpoint of possible disturbance to fish
species,potential loss of habitat,and possible
destruction of spawning beds.In addition,certain
species of fish are more sensitive than others to
disturbance.
Closely related to this consideration is the number
of stream crossings.The nature of the soils and
vegetation in the vicinity of the streams and the
manner in whi ch the streams are to be crossed are
E-10-59
2.4 -Transmission Alternatives
also important environmental considerations when
routing transmission lines.Potential stream
degradation,impact on fish habitat through
disturbance,and long-term negative consequences
resulting from siltation of spawning beds are all
concerns that need evaluation in corridor routing.
Therefore,the number of stream crossings and the
presence of fish species and habitat value were
considered when data were available.
(vii)Wildlife Resources
The three major groups of wil dl ife which must be
considered in transmission corridor screening are big
game,birds,and furbearers.Of all the wildlife
species to be considered in the course of routing
studies for transmission lines,big game species
(together with endangered species)are most signifi-
cant.Many of the big game species,including
grizzly bear,caribou,and sheep,are particularly
sensitive to human intrusion into relatively undis-
turbed areas.Calving grounds,denning areas,and
other important or unique habitat areas as identified
by the Alaska Department of Fish and Game were
incorporated into the screening process.
Many species of birds such as raptors and swans are
sensitive to human disturbance.Identifying the
presence and location of nesting raptors and swans
permits avoidance of traditional nesting areas.
Moreover,if this category is investigated,the
presence of endangered species (viz,peregr'ine
falcons)can be determined.
Important habitat for furbearers exi sts along many
potential transmission line corridors in the railbelt
area,and its loss or disruption would have a direct
effect on these animal populations.Investigating
habitat preferences,noting existing habitat,and
identifying populations through available information
are important steps in addressing the selection of
environmentally acceptable alternatives.
2.4.5 -Environmental Screening Method~~ogy
In order to compare the alternative corridors from an environ-
mental standpoi nt,the envi ronmental c ri teri a di scussed above
were combined into environmental constraint tables (Tables
E.10.21,E.10.22,and E.10.23).These tables combine information
for each corridor segment under study.This permitted the
E-10-60
-
-
-
-
-
2.4 -Transmission Alternatives
assignment of an environmental rating,which identifies the
relative rating of each corridor within each of the three study
areas.The assignment of environmental ratings is a subjective
technique intended as an aid to corridor screening.Those
corridors that are recommended are identified with an "A,"while
those corri dors that are.acceptabl e but not preferred are
identified with a "C."Finally,those corridors that are
considered unacceptable are identified with an "F."
The data base used for this analysis was obtained from:
-Existing aerial photos;
-U.S.geological survey maps;
-Land status maps;
-The report entitled,Hydroelectric Power and Related Purposes:
Southcentral Railbelt Area,Alaska,Upper Susitna River Basin,
Interim Feasi bili ty Report,prepared in 1975 by the U.S.Army
Corps of Engineers;
-The report entitled,Anchorage-Fairbanks Transmission Intertie,
Economic Feasibility Repo~t,prepared in 1979 by International
Engineering Company and Robert W.Retherford Associates;and
-Aerial and ground reconnaissance of the potential corridor.
These contraint tables were prepared in 1981-82,at which time
the routi ng of the proposed access road was undeci ded.Thus,
numerous corri dors refer to bei ng nea r a proposed access road.
Once the access road deci si on was reached in August 1982,these
corridors in the Central Study area were re-evaluated in light of
the common corridor concept for both access and transmission.
This re-evaluation is discussed in Section 2.4.10 below.
2.4.6 -Screening Results
Table E.10.24 summarizes the comparisons of the 22 corridors
studied in the southern,central,and northern study areas,prior
to the selection of the access road.Environmental,economical,
and technical ratings are presented as well as a summary rating
for each corridor.Because of the critical importance of
enviromental considerations,any corridor which received an F
rating for environmental impacts was assigned a summary rating of
F.Thus,a corridor which might be excellent from a technical
and economic viewpoint was considered not acceptable if the
environmental rating was unacceptable.
2.4 -Transmission Alternatives
Descriptions of the rationale for each corridor's rating are
presented below.
(a)Southern Study Area
Three alternative corridors were evaluated in the southern
study area.As previously identified,two corridors connect
Willow with Point MacKenzie.The third corridor connects
Willow with Anchorage.
(i)Corridor One (ABC I
) -Willow to Anchorage via Palmer
-Technical and Economical
Thi s 7 3-mil e (116 km)corri dor is the longest of
the three being considered for the southern area.
As a consequence,there wi 11 be more cl eari ng of
right-of-way required,more miles of line,and more
towers.Several highway and railway crossings will
a1 so be encountered,i ncl udi ng cross i ng of the
Glenn Highway.The corridor is located in a well-
developed,inhabited area which will requi re ease-
ments on private properties.There also could be a
problem of radio and television interference.
-Environmental
Several constraints were identified in evaluating
this corridor,chief among which were constraints
under the land use category.
A new right-of-way would be required from Willow to
a point in the vicinity of Palmer.This would
necessitate the development of a pioneer access
road and,since thi s area is wooded,attendant
vegetation clearing and opening of a previously
inaccessible area.The corridor also bisects lands
in the vicinity of Willow that had been proposed
for use as the new capital site.
Between Eklutna and Anchorage,this route parallels
an existing transmission 1 ine that now crosses
extensively developed areas.Parallelil1g existing
corridors usually is the most appropriate means of
traversing developed areas.Because homes and
associated buildings abut the right-of-way,how-
ever,additional routes through this developed area
present problems,among which aesthetics is most
important.In additi on,thi s corridor alternat ive
E-IO-62
2.4 -Transmission Alternatives
Summary
C
En vi ronmenta 1
C
Economical
C
crosses five rivers and 28 creeks potentially
affecting not only the rivers and streams but also
fish species inhabiting these watercourses.From
the standpoi nt of aesthetics,a t ransmi ssi on 1i ne
in the vicinity of Gooding Lake would negatively
affect an existing bird-watching area.However,
because this area is not heavily util ized and
routing variations are available within the
corridor,it is considered environmentally
acceptable.
Rati ngs:
Technical
C
(i i )Corridor Two (ADFC)-Willow to Point MacKenzie
via Red Shirt Lake
r-
I -Technical and Economical
r-
I,
l
-
-
Corri dor ADFC crosses the fewest number of ri vers
and roads in the southern study a rea.It has the
advantage of paralleling an existing tractor trail
for a good portion of its length,thereby reducing
the need for new access roads.Easy access will
allow maintenance and repairs to be carried out in
minimal time.This corridor also occurs at low
elevations and is approximately one-half the length
of Corridor One.
-Envi ronmental
This corridor crosses extensive wetlands from
Willow to Point MacKenzie.At higher elevations or
in the better drained sites,extensive forest cover
is encountered.Good agricultural soils have been
identified in the vicinity of this corridor;the
state plans an agricultural lands sale for areas to
be traversed by this corridor.The corridor also
crosses the Susitna Fl ats Game Refuge.The pres-
ence of an existing tractor trail near considerable
portions of this corridor diminishes the signifi-
cance of some of these constraints.Furthermore,
its short 1ength and the fact that it has only one
river and eight creek crossings increases its
environmental acceptability.
Ratings:
Techni cal
A
Economical
A
Envi ronmental
A
Summary
A
!""'"
I E-10-63
2.4 -Transmission Alternatives
(iii)Corridor Three (AEFC)-Willow to
Point MacKenzie via Lynx Lake
-Technical and Economical
This corridor has the same physical features as
Corridor Two.Both corridors have extensive wet-
1 ands.AEFC cuts across a developed recreat i ona 1
area and hence will require special routing proce-
dures to circumvent some of the private property it
will traverse.This corridor is very accessible.
Technically.because of its short length and low
elevation.it is a desirable corridor.but economi-
cally it would be costly to obtain easements and to
route the line through the several privately owned
properties.
-Environmental
As with the previous corridor.this route crosses
extensive wetlands requiring.in the better drained
areas.extensive clearing of associated forest.
Just south of Willow.this route passes through the
Nancy Lakes recreation area.Substantial develop-
ment of both residential and recreational facili-
ties has occurred in the past and is continuing.
These facilities would be affected by the presence
of the transmission line.not only from a land use
standpoint.but also from an aesthetics standpoint.
Because of this unavoidable land use conflict
associated with this corridor.particularly in the
Nancy Lake area.it is not considered to be
environmentally acceptable.
Ratings:
Technical
A
(b)Central Study Area
Economical
C
En vi ronmenta 1
F
Summary
F
Fifteen corridors utilizing different combinations of cor-
ridor segments were identified in the central study area.
These corridors connect,the damsites with the Intertie at
four separate locations.These locations are in the vicin-
ity of Indian River near its confluence with the Susitna
River and near the communities of Chulitna.Summit.and
Cantwell.
Because of the range in length of the corridors.those with
long lengths were assigned economic ratings of F.These
2.4 -Transmission Alternatives
corridors,numbers Four (ABCJHI),Five (ABECJHI),Seven
(CEBAHI),Eight (CBAG),Nine (CEBAG),Ten (CJAG),and Twelve
{JACJHI},have lengths of 76 to 97 miles {122 km to 158 km).
In addition to these,Corridors Four and Six (CBAHI)were
assi gned an F technical rating because they cross
mountainous areas over 4000 feet (1200 m)in elevation.
The eight corridors,although unacceptable economically (F
rating),were evaluated on an environmental basis.This was
done to determi ne whether one of these long corridors was
much more acceptable environmentally than a shorter one.
Therefore,envi ronmental i nformati on is presented for the
eight abovementioned corridors.This is followed by a
discussion of the economic,technical,and envi ronmental
features of the remaining seven corridors in the central
study area.
(i)Corridors Technically and/or
Economically Unacceptable
Corridor Four (ABCJHI)-Watana to Intertie via
Devil Creek Pass/East Fork Chulitna River
-
This corridor connects Devil Canyon with Watana and
exits the Devil Canyon project to the north fol low-
ing the drainages of Devil,Portage,and Tsusena
Creeks.To route this corridor to the Intertie as
requi red,the 1 ine crosses some mountain passes
over 4000 feet (1200 m)in elevation with steep
slopes and shallow bedrock areas (Corridor Segment
CJ HI)•
Summary
F
Economical-Environmental
F F
The transmission line would interrupt the existing
viewshed of the recreation facil ity at Hi gh Lake.
Existing patterns of land use in the vicinity of
High Lake may also be significantly disrupted by
the transmission 1 ine.Once on the north side of
the river,this corridor crosses 42 creeks between
Devil Canyon and the connection with the Intertie.
Potential for stream degradation exists because of
the lack of existing access.Sensitive wildlife
species,such as caribou,wolves,and brown bear,
as well as a golden eagle nest site,could be
potentially harmed by this corridor.
Ratings:
Technical
F
-
2.4 -Transmission Alternatives
Corridor Five (ABECJHI)-Watana to Intertie via
Stephan Lake and the East Fork Chulitna River
This corridor crosses areas of high elevations and
s hallow soi 1s underl ai n by bedrock.La nd use con-
straints are encountered in the vicinity of both
High Lake and Stephan Lake,two significant recre-
ation and lodge areas.Relatively important water-
flow and migrating swan habitat would be affected,
as would habitat for some of the major big game
species.In addition,this corridor makes 42 creek
crossings.Extensive vegetation clearing would be
required,opening areas to access.Because of the
visual impacts and increased access,this corridor
received an F rating.
Ratings:
Technical
F
Economical
F
Envi ronmental
F
Summary
F
-Corridor Six (CBAHI)-Devil Canyon to the
Intertie via Tsusena Creek/Chulitna River
Reversing the sequence by which the damsites are
connected,Corridor Six extends from Devil Canyon
to Watana (Corridor Segment CBA)and from Watana
north along Tsusena Creek to the point of connec-
tion with the Intertie near Summit Lake (Corridor
Segment AHI).Access roads are presently absent
along most of this corridor,and a pioneer route
would need to be establ ished.This corridor al so
traverses elevations above 4000 feet (1200 m)and
encounters shallow soils underlain by bedrock.
Wetlands,extensive forest cover,and 32 creek
crossings also constrain the development of this
corri dor.A bal d eagl e nest in the vi ci nity of
Tsusena Butte,as well as the presence of sensitive
big game species such as caribou and sheep,present
additional constraints to the routing of the corri-
dor.This corridor was rated F,primarily because
of increased access and potential negative impact
on sensitive wildlife species.
Rat i ngs:
Technical
F
Economi cal
F
Envi ronmenta 1
F
Summary
F
"...
I
I
!'""'"
!
2.4 -Transmission Alternatives
-Corridor Seven (CEBAHI)-Devil Canyon to Intertie
via Stephan Lake and Chulitna River
The primary environmental constraints associated
with this corridor are the result of visual and
increased access impacts.The corridor crosses
near residential and recreational facilities at
Stephan Lake and is in the viewshed of the Alaska
range.Access road construction would be necessary
through wetlands and areas of heavy timber.
In addition,the corridor crosses 45 creeks,inclu-
ding some with valuable spawning areas.It also
crosses habitat for wolves and bears,including
Prairie Creek which is heavily used by brown bears
during salmon runs.This offers the potential for
increased bear-human contacts.
Again,because of potential for visual impacts and
increased access,this corridor received an F rat-
i ng.
Ratings:
Technical
C
Economi cal
F
Env i ronmenta 1
F
Summary
F
r
-
.-
-Corridor Eight (CBAG)-Devil Canyon to Intertie
via Deadman/Brushkana Creeks and.Denali Highway
Constraints in the categories of land use,aesthe-
tics,and fish and wildlife resources are present
in this corridor.JIroong the longest of corridors.
under consideration,this route passes near recrea-
tion areas,isolated cabins,lakes used by float-
planes,and land-based airstrips.In traversing
lands from the Watana damsite to the point of con-
nection with the Intertie,the route also intrudes
upon some scenic areas.Along much of its length,
the corridor crosses woodlands and,since a pioneer
access road probably would be required,vegetation
clearing would 1ikely be extensive.Once north of
the Watana damsite,the transmission line corridor
makes 35 creek crossings and traverses the habitat
not only for a vari ety of sensitive big game spe-
cies but al so for waterfowl and raptors.In addi-
tion,the 1 ine passes near the location of an
active bald eagle nest on Deadman Creek.
E-10-67
2.4 -Transmission Alternatives
For these reasons,a rating of F was assigned.
Ratings:
Technical
C
Economical
F
Envi ronmental
F
Summary
F
-Corridor Nine (CEBAG)-Devil Canyon to Intertie
via Stephan Lake and Denali Highway
Corridor Nine is the longest under construction in
the central study area,and hence would require
disturbance of the largest land areas.It also
crosses areas of shallow bedrock,important water-
fowl migratory habitat at Stephan Lake,and 48
creeks,including valuable spawning areas.
The corridor passes near Stephan Lake,utilized
heavily for recreation,and any line constructed in
this area would be visible when looking towards the
Al aska range.Al though one of the proposed access
roads to the damsites is located in this area
offering the potential for parallel rights-of-way,
the extreme length of this corridor and the poten-
tial for unavoidable adverse land use and aesthetic
impacts result in its being judged unacceptable.
Thus,an F rating was assigned.
Rat ings:
Technical
C
Economical
F
Envi ronmental
F
Summary
F
-Corridor Ten (CJAG)Devil Canyon to Intertie via
North Shore,Susitna River,and Denali Highway
This is the second longest of the corridors under
investigation by this study.Routing above 3000
feet (900 m)and its concomi tant bedrock and steep
slopes are important restrictions of this corridor.
It would also encounter the land use constraints
identified in Corridor Nine,as well as several
other drawbacks,most notable of which are in the
areas of aesthetics and fish and wildlife resour-
ces.Forty-seven creek crossings would be required
by this corridor.
This corridor could also parallel one of the pro-
posed access roads.However,as with Corri dor
Nine,its long length,land use,and visual impacts
do not make it an acceptable corridor.
E-10-68
-
......
2.4 -Transmission Alternatives
All of the above and parti cul arly the aesthetic
constraints result in an F rating.
Ratings:
Technical
C
Economi cal
F
Envi ronmental
F
Summary
F
-Corridor Twelve (JA-CJHI)-Devil Canyon -Watana
to Intertie via Devil/Chulitna River
Thi s corridor has a number of envi ronmental con-
straints which together make it environmentally
unacceptable.Land use conflicts would likely
occur,since much of the land crossed is privately
owned.In addition,aesthetic impacts would occur
in the High Lakes area,because the corridor is in
the viewshed of the Alaska Range.Finally,the
corridor crosses 40 creeks,including valuable
salmon-spawning grounds,and crosses near a golden
eagl e nest.
This corridor,primarily because of impacts to
access,private lands,and aesthetics,received an
F rating.
Ratings:
Technical
C
Economical
F
Envi ronmental
F
Summary
F
(ii)Corridors Technically and Economically Acceptable
-Corridor One (ABCD)-Watana to the Intertie via
South Shore of the Susitna River
•Technical and Economical
Corridor One is one ..of the shortest corridors
considered,approximately 40 miles (64 km)long,
making it economically favorable.No technical
restrictions were observed along the entire
length of this corridor •
•Envi ronmental
Because of its short length,environmental dis-
turbance caused by transmission line construction
would be reduced.The more noteworthy con-
straints are those identified under the cate-
gories of 1 and use and vegetation.Corridor One
E-IO-69
2.4 -Transmission Alternatives
would require the development of a new right-of-
way between Watana and Devi 1 Ca nyon with some
opportunity existing to utilize the COE-developed
road for access between the Intertie and Devil
Canyon.Wetlands and discontinuous forest cover
occur in the corridor,especially in the eastern
third of the route.Access road development,if
required in this area,and the associated vegeta-
tion clearing present additional constraints to
this corridor.
Ratings:
Techn i cal
A
Economical
A
Environmental
A
Summary
A
-Corridor Two (ABECO)-Watana'to
Intertie via Stephen Lake
•Technical and Economical
This corridor is approximately five miles longer
than Corridor One and would require an additional
five miles of access road for construction pur-
poses.The corridor will rise to a maximum ele-
vation of 3600 feet (1080 m),and al so crosses
wetlands and extensive forest cover.This higher
elevation,increased clearing,and longer length
result in a lower technical and,economic rating
than Corridor One •
•Envi ronmental
This corridor is identical to Corridor One with
the except i on of Co rri dor Segment BEC.Because
of this deviation,several additional problems
arise in this corridor as compared with Corridor
On e.Fi rst,an access road about 9 mi 1es (14 km)
longer than that required for the construction of
Corridor One woul d be ne£Jed.A new road may
also have to be developed along most of this
route,which would al so cross wetland and
forested areas.Residential and recreational
facil Hies at Stephan Lake and the much higher
visibility of the transmission facilities to the
users of this recreation area would be a major
constraint posed by this corridor.
The cor-idor would also intrude upon habitat for
wolves,bear,and caribou,as well as for raptors
and waterfowl.Of note,brown bears utilizing
E-10-70
,.--
....2.4 -Transmission Alternatives
the fish resources of Prairie Creek would likely
encounter this alternative corridor more
frequently than they would Corridor One,thus
potentially bringing bears and people into close
contact.
These potential impacts to aesthetics and crea-
tion of a new access road result in this corridor
being environmentally unacceptable.
-Corridor Three (AJCF)-Watana to Intertie
via North Shore of the Susitna River
--
Ratings:
Technical
C
Economi cal
C
Envi ronmental Summary
F F
Environmental Summary
C C
"""I
-i
i
I
....
•Technical and Economical
This corridor is similar in length to Corridor
Two and shares the same technical and economical
considerations.There are no existing roads for
nearly the entire length,and it does encounter
some steep slopes.These will reduce the rel i-
ability of the line and add to the cost of con-
struction.
Envi ronmental
The corridor in this area would 1 ikely require a
pioneer access road.This route would also be
impeded by the existence of recreation facilities
in the vicinity of High Lake and,more signifi-
cantly,Otter Lake.The corridor is within sight
of recreation facilities at these lakes and may
also interfere with the use of High Lake by
planes during certain weather conditions.The
route also crosses Indian River and Portage
Creek;both streams support significant salmon
resou rces.Potenti al damage to spawni ng areas
could occur as a result of construction along
this corridor.An active golden eagle nest'
exists in the Devil Creek vicinity.This species
is sensitive to development activities and could
be adversely affected by Corridor Three.
Rat i ngs:
Technical Economical
C -C
E-10-71
2.4 -Transmission Alternatives
-Corridor Eleven (CJAHI)-Devil Canyon to the
Intertie via Tsusena Creek/Chulitna River
•Technical and Economical
This corridor has a disadvantage over the others
discussed because of its lO-mile (112 km)length.
New access roads and vegetative clearing would be
required for a considerable portion of the corri~
dor,thereby increasing costs of construction.
•Env i ro nmenta 1
Corridor Segments CJA (part of Corridor Three)
and AHI (part of Corridor Six)comprise this
alternative and,as such,have been previously
discussed.The long length of this corridor,its
crossing of 36 creeks,and development of a new
right-of-way and land use conflicts contribute to
an unacceptable environmental rating.
Ratings:
Techni cal
C
Economi ca 1
C
Envi ronmental
F
Summary
F
-Corridor Thirteen (ABCF)-Watana to Devil
Canyon via South Shore,Devil Canyon to
Intertie via North Shore,Susitna River
•Technical and Economical
This corridor,41 miles (66 km)-in length,is one
of the shorter ones being considered.Although
it crosses deep ravines and forest clearing will
be required over a considerable portion of its
1 ength,it is rated hi gh techni cally because of
its short length and low elevation.
•Envi ronmental
Since this corridor combines segments from Corri-
dor One (ABC)and Corridor Three (CF),the same
constraints for those two routes apply which have
been previously described.This corridor pre-
sents a few environmental problems.Conflicts
wi th recreat ion near at ter Lake can be resolved
t hroug h careful sel ecti on of the fi nal ri ght-
of-way.
E-10-72
-
2.4 -Transmission Alternatives
Rat i ngs:
Technical
A
Econ omi cal
C
Envi ronmental
A
Summa ry
A
-
-
-i
r
-Corridor Fourteen (AJCD)-Watana to Devil
Canyon vi a North Shore,Devi 1 Canyon to
Inttertie via South Shore,Susitna River
•Technical and Economical
Thi s corridor is al so one of the shortest among
the fifteen studi ed in the central area.Some
access roads will be requi red for th is corri dor
and some clearing necessary.Advantage will be
taken of the proposed project access road where
possible to locate the transmission line close
by.
Corri dor-Fourteen is rated as recommended both
economically and techni cally,because of gentl e
relief,short length,and small amounts of
c 1ea ri ng.
•Envi ronmental
This corridor reverses the routing between dam-
sites and the Intertie proposed by Corridor
Thirteen.Constraints are,therefore,the same
as those presented for Corridors Three and One,
and are not great.However,the unavoidable
conflict with land use at High Lake results in a
Crating.
Ratings:
Tec hn i cal Economi ca 1
A A
Envi ronmental
C
Summary
A
-Corridor Fifteen (AFECF)-Watana to Devil
Canyon via Stephan Lake,Devil Canyon to
Intertie via North Shore,Susitna River
•Technical and Economical
This corridor is approximately 45 miles (72 \m)
long and would require construction of new access
roads and forest cl eari ng for almost its enti re
1ength.These negat i ve economi ca 1 poi nts con-
tribute to the low rating of this corridor.
E-10-73
2.4 -Transmission Alternatives
•Envi ronmental
This corridor combines segments from Corridor Two
(ABEC)and Corridor Three (CF).The constraints
for these corridors have been presented under
their respective discussions.Extensive new
access and detrimental vi sual impacts near
Stephan Lake were the primary constraints along
the corridor segment from Corridor Two which
resulted in an unacceptable environmental
rating.
Ratings:
Technical
C
(c)Northern Study Area
Economical
C
Environmental Summary
F F
Constraints appeared in the routing of all 4 corridors
eval uated in the northern stu€ly area.The shortest route
was 85 miles (136 km)and the longest was 115 miles
(184 km).Topography and soils restrictions are constraints
to each of the corridors evaluated.In addition,the two
eastern corridors of the study area cross mountain slopes.
Each of the corridors would be highly visible in the flood-
plain of the Tanana River.Major highways skirt these
floodplains at some distance to the north,however,and only
scattered,isolated residential areas would be encountered
by the corridors.Little information has been collected
concerning the cultural resources in the vicinity of any of
the four corridors of this study area.The Dry Creek
archaeologic site near Healy has been identified;however,
the presence of numerous sites in the foothi 11 s of the
Alaska Range and in the vicinity of the Tanana River are
suspected.Additi onal constraints pecul i ar to the four
separate corridors are presented below.
(i)Corridor One (ABC)-Healy to
Fairbanks via Parks Highway
-Technical and Economical
This corridor crosses the fewest water courses in
the northern study area.Although it is approxi-
mately 4 miles (6 km)longer than Corridor Two,it
is technically favored because of the existence of
potential access roads for almost the enti re
1ength.
E-10-74
2.4 -Transmission Alternatives
-Envi ronmental
Because it parallels an existing transportation
corridor for much of its 1 ength,t hi s corri dor
woul d permit 1 ine routing that woul d avoid most
visually sensitive areas.The three proposed road
crossings for this corridor (as opposed to the 19
road crossings of the Healy-Fairbanks transmission
line)could occur at points where roadside develop-
ment exists,in areas of visual adsorption capabil-
ity,or in areas recommended to be opened to long-
.distance views.
Four ri vers and 40 creeks are crossed by this cor-
ridor,with potenti al for impacts.It crosses the
fewest number of water courses of any route under
consideration in the northern study area.In addi-
tion,the inactive nest site of a pair of peregrine
falcons occurs within this proposed corridor.
As with visual impacts,land use,wildlife,and
fishery resource impacts can be lessened through
careful route location and utilization of existing
access.Impacts on forest clearing can also be
lessened through the sharing of existing transmis-
sion line corridors.
Ratings:
Techn ical
A
Economical
A
Envi ronmental
A
Summary
A
(ii)Corridor Two (ABDC)Healy to
Fairbanks via Wood River Crossing
t-
!Technical and Economical
This 86-mile (138-km)corridor is the shortest
f"""studied in this area.Although cornparabl e to
Corridor One,it crosses additional wetlands,
increasing the tech~ical difficulty of transmission
_line construction.Development of roads will also
pose a major constraint.
-Envi ronmental
Corridor Two is the shortest under consideration in
the northern study area.Since it is a variation
of Corridor One,many of the same constraints apply
here.The lack of existing rights-of-way is a con-
strai nt throughout much of thi s route.Pri or to
E-10-75
2.4 -Transmission Alternatives
crossing the Tanana River,this corridor deviates
farther to the northeast than does Corridor One,
thereby crossing additional wet soils;thus,
access-road development poses a major constraint.
Forest clearing would be necessary in the broad
floodpla"in of the Tanana River.While it is the
shortest route,this corridor still crosses fi ve
ri vers and 44 creeks as well as pri me habitat and
important habitat for peregrines and golden eagles.
These constraints,and visual and public land con-
flicts,result in a Crating.
Rat i ng s:
Technical
C
Economi ca 1
A
Envi ronmental
C
Summary
C
(iii)Corridor Three (AEDC)-Healy to Fairbanks
via Healy Creek and Japan Hills
-Technical and Economical
This 115-mile (l84-km)corridor is the longest in
the northern study area.Its considerable length
would contribute substantially to increased costs
of construction.The crossing of areas over 4500
feet (1350 m)"j n e 1 evat ion resu lts in the corri dor
being technically unacceptable for reasons dis-
cussed above.
-Envi ronmental
This corridor crosses a high mountain pass and,in
some locations,encounters bedrock overlain with
shallow,wet soils.Access is a problem because,
except for the road into the Usibelli coal fields,
no ri ghts-of-way exi st along the route.Crossi ng
the broad floodplain of the Tanana and Wood Rivers
would require extensive forest clearing and result
in aesthetic impacts.In addition,this corridor
involves three river and 72 creek crossings.Prime
habitat for caribou,peregrine falcons,sheep,and
waterfowl as well as important habitat for golden
eagles and brown bear would be affected.
The increased length and increased visual impacts
result in this corridor being environmentally
unacceptable.
Ratings:
Technical
F
Economi cal
C
E-10-76
Envi ronmental
F
Summary
F
....
....
-,
....
2.4 -Transmission Alternatives
(iv)Corridor Four (AEF)-Healy to Fairbanks
via Wood River and Fort Wainwright
Technical and Economical-
The technical and economical constraints associated
with this corridor are the same as those in Corridor
Three.The long distance of this corridor (105
miles,or 166 krn)and the crossing of areas over
4500 feet (1350 m)in elevation reduce its attrac-
tiveness from a technical and economical viewpoint.
-Envi ronmental
Corridor Four is very simil ar to Corridor Three in
that it parallels Healy Creek drainage north.
Therefore,impacts to this mountainous region would
be i dent i ca 1 to those descri bed for thi s corri dor
segment in Corridor Three.In the vicinity of Japan
Hills,however,the corridor parallels an existing
sled road for part of its length as it traverses the
wet,heavily forested fl oodpl ai n of the Tanana and
Wood Rivers.Clearing requirements might,there-
fore,be reduced,as woul d be the need for access
roads in this area.Important habitat or prime
habitat for peregrine falcons,bald eagles,sheep,
caribou,and brown bear exists within this corridor •
This corridor is unacceptable from a land use stand-
point because it is within the Blair Lake Air Force
active bombing range.
Ratings:
Technical
F
2.4.7 -Proposed Corridor
Economi cal
C
Envi ronmental
F
Summary
F
Therefore,the recommended corridor for the Susi tna project at
this point in the analyses consisted of the following segments:
-Southern study area,Corridor ADFC;
-Central study area,Corri~or ABCD;and
-Northern study area,Corridor ABC.
These appear in Figures E.10.10,E.10.11,and E.10.12.
E-10-77
2.4 -Transmission Alternatives
2.4.8 -Route Selection Methodology
After identifying the preferred transmission line corridors,the
next step in the route selection process involved the analysis of
the data as gathered and presented on the base maps.The map is
used to select possible routes within each of the three selected
corridors.By placing all major constraints (e.g.,area of high
vi sual exposure,pri vate 1ands,endangered speci es,etc.)on one
map,a route of least impact was selected.Existing facilities,
such as transmission 1 ines and tractor trails within the study
area,were also considered during the selection of a minimum
impact route.Whenever possible,the routes were selected near
existing or proposed access roads,sharing whenever possible
existing rights-of-way.
The data base used in this analysis was obtained from the
following sources:
-An up-to-date land status study;
-Existing aerial photos;
New aerial photos conducted for selected sections of the previ-
ously recommended transmission line corridors;
-Environmental studies,including aesthetic considerations;
-Climatological studies;
-Geotechnical exploration;
-Additional field studies;and
-Public opinions.
2.4.9 -Environmental Route Selection Criteria
The purpose of this section is to identify three selected routes:
one from Healy to Fairbanks,the second from the Watana and Devil
Canyon damsites to the Intert ie,and the thi rd from Wi 11 ow to
Anchorage.Route location objectives were to obtain an optimum
combination of reliability and cost with the fewest environmental
problems.
The previously chosen corridors were subject to a process of
refi ni ng·and eval uati on based on the same techni cal,economi c,
and environmental criteria used in corridor selection.In addi-
tion,special emphasis was concentrated on the following points:
-Satisfaction of the regulatory and permit requirements;
-Selection of routing that provides for minimum visibility from
highways and homes;and
-Avoidance of developed agricultural lands and dwellings.
2.4 -Transmission Alternatives
The corridors selected were analyzed to arrive at the route width
which is the most compatible with the environment and also meets
the engineering and economic objectives.The environmental anal-
ysis was conducted by the process described below:
(a)Literature Review
Data from various literature sources,agency communications,
and site visits were reviewed to inventory existing environ-
mental variables.From such an inventory,it was possible
to identify en vi ronmental con stra i nts in the recommended
corridor locations.Data sources were cataloged and filed
for later retrieval.
(b)Avoidance Routing by Constraint Analysis
To establish the most appropriate location for a transmis-
sion line route,it was necessary to identify those environ-
mental constraints that could be impediments to the develop-
ment of such a route.Many specific constraints were iden-
tified during the preliminary screening;others were deter-
mined during the 1981 field investigations.
-(c)
By utilizing information on topography,existing and pro-
posed land use,aesthetics,ecological features,and cul-
tural resources as they exi st withi n the corri dors,and by
careful placement of the route with these considerations in
mind,impact on these various constraints was minimized.
Base Maps and Overlays
Constraint analysis information was placed on base maps.
Const raints were i denti fi ed and presented on overl ays to the
base maps.This mapping process involved using both exist-
ing information and that acquired through Susitna project
studies.This information was first categorized as to its
potential for constraining the development of a transmission
line route within the preferred corridor and then placed on
maps of the corridors.Environmental constraints were iden-
tified and recorded directly onto the base maps.Overlays
to the base maps were prepared,indicating the type and ex-
tent of the encountered constraints.
Three overlays were prepared for each map:one for visual
constraints,one for man-made,and one for biological con-
straints.,These maps are presented in Acres/TES 1982.
E-I0-79
2.4 -Transmission Alternatives
2.4.10 -Evaluation Following Access Road Decision
In September 1982,the Alaska Power Authority Board of Directors
selected the Denali-North Plan as the proposed access route for
the Susitna development.The location of existing and proposed
access is of prime importance both from an economi c and envi ron-
mental standpoint.Therefore,subsequent to the access decision,
each of the four corridors within the Central Study Area was sub-
jected to a more detailed evaluation and comparison.
Within these corridors,a number of alternative rout-ings were
developed and the route in each corridor which was found to best
meet the selection criteria was retained for further analysis.
The four corridors are comprised of the following route seg-
ments:
Corridor One
Corridor Three
Corridor Thirteen
Corridor Fourteen
ABCD
AJCF
ABCF
AJCD
It is evident that there are two acceptable segments (segments
ABC and AJC),to link Watana and Devil Canyon;and silll"ilarly,two
segments (segments CD and CF)to 1 ink Devil Canyon with the
Intertie.On closer examination of the possible routes between
Devil Canyon and the Intertie,the route in segment CD was found
to be superi or to the route in segment CF for the foll owi ng
reasons:
(a)Economic
A four-wheel drive trail is already in existence on the
south side of the Susitna River between Gold Creek and the
proposed location of the railhead facility at Devil Canyon.
Therefore,the need for new roads along segment CD,both for
construction and operation and maintenance,is significantly
less than for segment CF,which requires the construction of
a pioneer road.In addition,the proposed Gold Creek to
Devil Canyon rai 1 road extension will al so run parallel to
segment CD.
Another primary economic aspect considered was the length of
the corri dors.However,since the 1engths of segments CD
and CF are 8.8 miles (14 km)and 8.7 miles (14 km),respec-
tively,this was not a significant factor.
One of the secondary economic considerations is that of top-
ography.Segment CF crosses more rugged terrain at a higher
elevation than segment CD and would therefore prove more
E-1O-80
-I
2.4 -Transmission Alternatives
difficult and costly to construct and maintain.Hence,seg-
ment CD was consi dered to have a hi gher overall economi c
rating.
-
-
-,
-
-
(b)
(c)
Technical
Although both segments are routed below 3000 feet (900 m)in
elevation,segment CF is slightly more difficult since it
crosses more rugged,exposed terrain with a maximum el eva-
t i on of 2600 feet (778 m).Segment CD,on the other hand,
traverses generally flatter terrain and has a maximum eleva-
t ion of 1800 feet (540 m).The di sad vantages of segment CF
are somewhat offset,however,by the Susitna River crossing
that will be needed at river mile 150 for segment CO.Over-
all,the technical difficulties associated with the two seg-
ments are regarded as being similar.
Environmental
One of the main concerns of the various environmental groups
and agencies is to keep any form of access away from sensi-
tive ecological areas previously inaccessible except by
foot.Creating a pioneer road to construct and maintain a
transmission line along segment CF would open that area up
to all-terrain vehicle and public use and thereby increase
the potential for adverse impacts to the envi ronment.The
potential for envi ronmental impacts along segment CD woul d
be present regardl ess of whether or not the transmi ss i on
1 ine was built since there is an existing four-wheel drive
trail,together with the proposed railroad extension in that
area.It is clearly desirable to restrict environmental
impacts to a single common corridor and for that reason,
segment CD is preferable to segment CF from an environmental
standpoint.
Large ly because of the potent ia 1 envi ronmenta 1 impacts,but
also because of the technical and economic ratings,segment
CF was dropped in favor of segment CD.Consequently,corri-
dors three (AJCF)and thi rteen (ABCF)were el imi nated from
further consideration.
The two corridors remaining are,therefore,corridors one
(ABCD)and fourteen (AJCD).More specifically,this reduces
to a comparison of alternative routes in segment ABC on the
south side of the Susitna River and segment AJC on the north
side.These routes were then screened in accordance with
the criteria set out in section (c)Corridor Screening to
determine the recommended route.The key points of this
evaluation are outlined below:
E-10-81
2.4 -Transmission Alternatives
(d)Economi c
For the Watana developnent,two 345-kv transmission lines
need to be constructed from Watana through to the Intertie.
When comparing the relative lengths of transmission 1 ine,it
was found that the southern route utilizing segment ABC was
33.6 miles (55 km)in total length compared to 36.4 miles
(60 km)for the northern route usi ng segment AJC.Al though
at first glance a difference in length of 2.8 miles (5 km)
(equivalent to 12 towers at a spacing of 1200 feet or
360 m),seems significant,other factors have to be taken
into account.Segment ABC contains mostly woodland,black
spruce in segment AB.Segment BC contains open and woodland
spruce forests,low shrub,and open and closed mixed forest
in about equal amounts •.Segment AJC,on the other hand,
contains significantly less vegetation and is composed pre-
dominantly of low shrub and tundra in segment AJ and tall
shrub,low shrub,and open mixed forest in segment JC.Con-
sequent ly,the amount of cl eari ng assoc i ated wi th segment
AJC is considerably less than with segment ABC,resulting in
savings not only during construction but also during peri-
odic recutting.Also,additional costs would be incurred
with segment ABC due to the increased spans needed to cross
the Susitna River (at river mile 165.3)and two other major
creek crossings.In summary,the cost differential between
the two routes would probably be marginal.
(e)Technical
Segment AJC traverses generally moderately,sl opi ng terrain
rangi ng in hei ght from 2000 feet to 3500 feet (600 to
1050 m)with 9 miles (15 km)of the route being at an eleva-
t ion in excess of 3000 feet (900 m).Segment ABC traverses
more rugged terrain,crossing several deep ravines and
ranges Tn height from 1800 feet to 2800 feet (540 to 840 m).
In general,there are advantages of rel iabil ity and cost
associated with transmission 1 ines routed under 3000 feet
(900 m).The nine miles of segment AJC at elevations in
excess of 3000 feet (900 m)will be subject to more severe
wind and ice loadings than segment ABC and the towers will
have to be strengthened accordingly.However,these addi-
tional costs will be offset by the complexity of towers
needed to accommodate the more rugged topography and major
ri ver and creek crossings of segment ABC.The techni cal
difficulties associated with the two segments are therefore
con sid e re d si mila r.
E-10-82
2.5 -Borrow Site Alternatives
,...
-
(f)Envi ronmental
From the previous analysis,itis evident that there are no
significant differences between the two routes in terms of
technical difficulty and economics.The deciding factor,
therefore,is the envi ronmental impact.The access road
routi ng between Watana and Devi 1 Canyon was selected because
it has the least potenti al for creati ng adverse impacts to
wildlife,wildlife habitat,and fisheries.,Similarly,seg-
ment AJC,which parallels the proposed access road,is
environmentally less sensitive than segment ABC for it tra-
verses or approaches fewer areas of producti ve habi t at and
zones of species concentration or movement.The most impor-
t ant consi derati on,however,is that,for ground access dur-
i ng operati on and mai ntenance,it wi 11 be necessary to have
some form of trai 1 along the transmi ssi on li ne route.Thi s
trai 1 would permi t human entry into an area whi ch is rela-
tively inaccessible at present causing both direct and in-
direct impacts.!By placing the transmission line and access
road within the same general corridor as in segment AJC,im-
pacts will be confined to that one corridor.If access and
transmission are placed in separate corridors,as in segment
ABC,environmental impacts would be far greater.
,....
Segment AJC is thus consi dered superi or to segment ABC.
Consequently,corridor one,(ABCD)was eliminated and corri-
dor fourteen (AJCD)selected as the proposed route.
2.4.11 -Conclusions
Thus,the recommended corridors for the Susitna project consist
of:Southern study area,Corri dor ADFC;Central study area,
Corridor AJCD,and Northern study area,Corridor ABC.
The proposed transmi ssi on li ne route is presented in Exhi bi t G.
The marked route represents the centerline of a 300-foot (90 m)
right-of-way which is sufficient for two single-circuit,parallel
lines.Between Devil Canyon and the Intertie,the right-of-way
is 510 feet (153 m)to accommodate four single-circuit lines.
2.5 -Borrow Site Alternatives
2.5.1 -Watana Borrow Sites
A total of seven borrow si tes and three quarry si tes have been
identified for dam construction material (A,B,C,D,E,F,H,I,
J,and L)(Fi gure E.10.13).Of these,Borrow Si tes D and Hare
consi dered as potenti al sources for semi per vi ous to pervi ous
material;Sites C,E,and F for granular material;Sites I and J
for pervious gravel;and Quarry Sites A,B,and L for rockfi 11.
E-10-83
2.5 -Borrow Site Alternatives
Several of these sites (B,C,and F)previously identified by the
Corp of Engineers were not consi dered as primary sites for this
study because:1)a source of suitable material exists closer to
the damsite;2)of adverse environmental impacts;3)of insuffi-
ci ent quant ity;or 4)of poor quality of the materi al •The re-
fore,no work was performed in these areas during 19S0-81.These
sites,however,have not been totally eliminated from considera-
t i on as alternat i ve sources and a re therefore i ncl uded in thi s
discussion.
Since adequate quality and quantity of quarry rock are readily
available adjacent to the damsites,the quarry investigation was
principally limited to general field reconnaissance to delineate
boundaries of the quarry sites and to determine approximate re-
serve capacity.This allowed for a more detailed investigation
in the borrow sites.
The borrow investigations consisted of seismic refraction sur-
veys,test pits,auger holes,instrumentation,and laboratory
testing.The results of this study are discussed below.
Each site is descri bed accordi ng to the foll owi ng characteri s-
ties:
-Proposed use of the materi al and why the site was se1 ected;
-Location and ge010gy,including topography,geomorphology,
vegetation,climatic data,ground water,permafrost,and strat-
igraphy;
-Reserves,lith010gy,and zonation;
-Engineering properties which include index properties and
laboratory test results;and
-Environmental information,where available.
Laboratory test resul ts on sampl es from the borrow sites are
shown in Acres (19S2a).
(a)Quarry Site A
(i)Proposed Use
Quarry Site A is a large exposed diorite and andesite
porphyry rock knob at the south abutment of the
Watana damsite.The predominant rock type is dio-
rite.The proposed use for the quarry is for b1asted
rockfill and riprap.
E-10-84
-2.5 -Borrow Site Alternatives
Quarry Site A was selected based on its apparent good
rock quality and close proximity to the damsite.
-
..-
i
-
(i i )Location and Geology
The boundaries of Ouarry Site A include the bedrock
"knob"from a pprox·illlate El evati on 2300 feet (240 m)
to about 2600 feet (330 m).The knob covers an area
approximately one square mile (2.6 km 2 ).Glacial
scouring has gouged out east-west swales in the rock.
These swales likely corresponded with fractured,
sheared,and altered zones within the rock body.
Overburden ranges from 0 to several feet over the
site.Vegetation is limited to scrubby spruce,
vines,and tundra,with limited alder growth in the
lower areas.Surface water is evident only in isola-
ted deeper swales.The ground water table is expec-
ted to be deep in this area with an estimated average
depth to the water table from 50 to 100 feet (14 to
30 m).It is likely that the ground water level will
be near the quarry floor during operation,but in-
flows are expected to be small,diminishing with
time.
Although no borings have been drilled in this site,
it is likely that permafrost will be encountered as
shallow as 5 feet (1.6 m)in depth.The permafrost,
however,is near the thaw point and,because of the
high exposure to sunlight in this area,is expected
to dissipate rapidly.The permafrost zones are
expected to be more common in the more fractured and
sheared zones.
The western portion of the site has been mapped as
sheared andesite porphyry with the remai nder of the
site being gray diorite.Mapping on the northern
hal f of the site showed the rock to grade between
black andesite porphyry and a coarse-grained gray
andesite with sections grading into diorite.Despite
these lithologic variations,the rock body is rela-
ti vely homogeneous •Based on ai rphoto i nterpreta-
tion,severe shearing and alteration appear to be
present on the northeast corner of the del i neated
site area.
(iii)Reserves
The rock exposure in Quarry Site A provided adequate
confidence in assessing the qual ity and quantity of
2.5 -Borrow Site Alternatives
available rockfi11 necessary for feasibility.Allow-
ing for spoilage of poor quality rock caused by
alteration and fracturi ng,and assuming a minimum
bottom elevation of 2300 feet (700 m),the estimated
volume of sheared or weathered rock is 23 million
cubic yards (mcy)(17.5 million cubic meters [mcmJ)
and 71 mcy (54 mcm)of good quality rock.
Additional rockfill,if required,can be obtained by
deepening the quarry to near the proposed dam crest
elevation of 2210 feet (660 m)without adversely
affecti ng the dam foundation or integrity of the
reservoi r.
(iv)Engineering Properties
Weathering and freeze-thaw tests were conducted to
determine the rock IS resistance to severe envi ron-
mental conditions.Results indicate that the rock is
very resi stant to abrasion and mechani cal breakdown,
se1 dom los i ng st rength or durab-i 1 ity in presence of
water and demonstrating high resistance to breakdown
by freeze-thaw.
The rock is expected to make exce11 ent ri prap,rock
shell,or road foundation material.
(v)Environmental
This area is covered primarily with black spruce and
shrub1and,except on the central portion,which is
mat and cushion tundra.It has a low sensitivity to
environmental disturbance.
(b)Quarry Site B
(i)Pro po s ed Us e
Quarry Site B was identified in previous investiga-
tions as a potential rock quarry for dam construc-
tion.The area was identified based on outcrops
exposed between E1 evat ions 1700 and 2000 feet (509
and 600 m)along the Susitna River and Deadman Creek.
During the 1980-81 field reconnaissance,mapping and
additional seismic refraction surveys were performed
in this area.
E-10-86
-
,tf9ii/iliIIJ
,.....
2.5 -Borrow Site Alternatives
(ii)Location and Geology
Quarry Site B is located about 2 miles (3 km)
upstream from the damsite between elevations of 1700
and 2000 feet (515 and 600 m).This area initially
appeared economically attractive because of the
short-haul distance and low-haul gradient to the
damsite.However,geologic mapping and seismic
refraction surveys performed in this area indicate
that the rock is interfingered with poor quality
sedimentary volcanic and metamorphic rocks with thick
overburden in several areas.
Vegetation cover is heavy,consisting of dense alder
marshes and alder with aspen and black spruce in the
higher,drier areas.The entire south-facing side of
the site is wet and marshy with numerous permafrost
features.The quarry side facing Deadman Creek is
dry,with thick till overburden,which appears
frozen.Permafrost in the area is expected to be
continuous and deep.Surface runoff from Borrow Site
D flows southward passing through Quarry Site B.
,...,(i i i )
(i v)
Reserves
Because of the deep overburden,generally poor rock
qual ity,and the extreme vegetation and topographic
relief,Quarry Site B was not considered as a primary
quarry site.Therefore,no reserve quantities were
determined for feasibility.
Engineering Properties
No material property testing was performed for this
area.
(v)Envi ronmental
This area is small,adjacent to other construction
areas,and primarily within the proposed reservoir.
As such,additional environmental disturbances will
r-not be great.
-(c)Borrow Site C
(i )Proposed Use
Borrow Site C was identified in previous studies as a
'possible source of gravels and sands for filter mate-
rial.The 1980-81 investigation identified adequate
E-I0-87
2.5 -Borrow Site Alternatives
volumes of granular material much closer to the
damsite in Borrow Site E.Therefore,no additional
work was performed in this area during this study.
(ii)Location and Geology
Borrow Site C,as delineated by the COE,extends from
a point approximately 4.5 miles (7.2 km)upstream
from Tsusena Butte to the northwest toe of the butte.
The site is a broad glacial valley filled with till
and alluvium.Vegetation ranges from alpine tundra
on the valley walls to heavy brush and mixed trees at
the lower elevations,thinning to mixed grass and
tundra near the river and on terraces.The ground
water table is assumed to be a subdued replica of the
topography,being shallow on the valley walls with
gradients towards the valley floor.Ground water
migration is expected to be rapid through the high1y
permeable alluvial material.Permafrost may be
intermittent.
The stratigraphy appears to consist of over 200 feet
(60 m)of basal till overlain by outwash,and
reworked outwash alluvium.The upper 100 to 200 feet
(30 to 60m)of material is believed to be saturated
gravels and sands.
(iii)Reserves
Because the site is not currently being considered as
a borrow source,no detailed quantity estimate has
been made.However,assuming an approximate area of
1500 acres (600 ha)and an excavation depth of 15
feet (4.5 m)above water table,a gravel quantity on
the order of 25 mcy (19 mcm)can be approximated.
Additional quantities may be obtained at depth;how-
ever,further studi es wi 11 be requi red to determi ne
the vol urn es•
(iv)Engineering Properties
The test pit and reconnaissance mapping show the
materi al in the fl oodpl ai n and terraces to be a
4-inch minus,well-washed gravel with approximately
60 percent gravel,40 percent sand,and negligible
fines.The gradations are representative of a clean,
well-washed material with a percentage of cobbles and
fi nes at depth.
E-10-88
2.5 -Borrow Site Alternatives
(v)Environmental
The distance of the site from Watana Dam would
require construction of a haul road with associated
impacts.The area also contains moose winter browse~
and the potential exists for degradation of Tsusena
Creek.There are also nine known archeological sites
within the area.These reasons are partially why
this area is not considered a primary site.
(d)Borrow Site D
-
.-
-
(i )Proposed Use
Borrow Site D was identified in 1975 as a potential
primary source for impervi ous and semi pervi ous mate-
rial by the COE •
Based on the fi e1d studies performed by the COE in
1978~it was tentatively concluded that:
-Borrow Site D had potentially large quantities of
clay and silt;
-The deposit was of adequate vol ume to provide the
estimated quantity of materi al needed for
const ruct i on;and
-The site had favorable topography and hydrology for
borrow development.
As a result of these previous studies~Borrow Site D
became a primary site for detailed investigation
during the 1980-81 study.
(ii)Location and Geology
Borrow Site 0 lies on a broad plateau immediately
northwest of the Watana damsite.The southern edge
of the site lies approximately 1/2 mile (0.8 km)
northeast of the dam 1 imits and extends eastward
towards Deadman Creek for a distance of approximately
3 miles (5 km).The topography slopes upward from
the damsite elevation of 2150 feet (645 m)northward
to approximate elevation of 2450 feet (735 m).
The g round surface has local i zed benches and swales
up to 50 feet (15 m)in height.The ground.surface
drops off steeply at the slopes of Deadman Creek and
the Susitna River..
E-10-89
2.5 -Borrow Site Alternatives
Vegetation is predominantly tundra and sedge grass,
averaging about one foot thick with isolated strands
of spruce trees on the higher and drier portions of
the site.
Climatic conditions are similar to those at the dam-
site with the exception that the borrow site is more
exposed to winds and sunlight.The relatively open
rolling topography is conducive to drifting and blow-
ing snow,frequently resulting in drifts up to 6 feet
(1.8 m)dee p.
The northwest portion of the site has numerous lakes
and shallow ponds with the remaining portions of the
site having localized standing water perched on
either permafrost or impervious soil s.Surface run-
off is toward Deadman Creek to the northeast and
Tsusena Creek to the west.Generally,much of the
area is poorly drained,with many of the low-lying
areas wet and boggy.
Instrumentation installed throughout the borrow site
shows intermittent "warm"permafrost.Temperatures
in the permafrost zones are all within the _1°C
range.Thermistor plots show annual frost
penetration of approximately 15 to 20 feet (4.5 to
6 m).Annual amplitude (fluctuation)in ground
temperature reaches depths of 20 to 40 feet (6 m to
12 m).The greatest depth of temperature amplitude
is in the unfrozen holes,while the permafrost holes
reach 20 to 25 feet (6 m to 7.5 m).This may be
caused by either the effect of greater water content
at the freezing interface lessening the seasonal
energy variations,or the thicker vegetation cover in
the permafrost area causing better insulation.
(iii)Reserves
The boundaries of the borrow site are somewhat
arbitrary,being limited on the south side by the
apparent limit of undisturbed material;to the east
by Deadman Creek;to the northwest by low topography;
and to the north by shall owi ng bedrock.If further
studies indicate the need for additional material s,
it may be feasible to extend the borrow site to the
northwest and west.Factors to be considered in
borrow site expansion are:
Siting of other facilities in this area;
-Impacts on the relict channel;
E-10-90
-
2.5 -Borrow Site Alternatives
-Haul distance;and
-Environmental impacts.
The reserve estimates for Borrow Site 0 have assumed
an average material thickness throughout the site
1imits.Based on the currently establ ished bound-
aries (encompassing about 1075 acres,or 430 hal and
an excavation depth of 120 feet (36 m),a total of
200 mcy (152 mcm)of material is available.
(iv)Engineering Properties
Grain size distribution within the borrow site ranges
from coarse gravels to clay.Almost all samples were
well-graded,ranging fran gravel to fine silt and/or
c1 aYe Moisture contents range from a low of 6 per-
cent to a high of 42.5 percent with an average of
approximately 14 percent.
(v)Envi ronmental
This area is mixed forest and shrubs.No known envi-
ronmental problems are identified.
(e)Bo rrow -Site E
(i)Proposed Use
Borrow Site E was identified by the COE as a princi-
pal source of concrete aggregate and fi 1ter materi al
for the Watana dam.The apparent vol ume of materi al
and its close proximity to the site made it the pri-
mary site for detailed investigations during the
1980-81 program.
(ii)Location and Geology
Borrow Site E is located 3 miles (1.5 km)downstream
from the damsite on the north bank at the confluence
of Tsusena Creek and the Susitna River.The site is
a large,flat alluvial fan deposit 'which extends for
12,000 feet (3600 m)east-west and approximately 2000
feet (600 m)northward froo the Susitna River up
Tsusena Creek.Elevation across the site varies from
a low of 1410 feet (423 m)near river level to 1700
feet (510 m)where the alluvial and terrace materials
lap against the valley walls to the north.
E-I0-91
2.5 -Borrow Site Alternatives
The area is vegetated by dense spruce and some
alders,tundra,and isolated brush.Vegetation cover
averages about one foot thi ck underl ai n by up to 4
feet (1.2 m)of fine silts and volcanic ash.
Ground water was found to be genera 11y greater than
10 feet (3 m)deep.Ground water levels fluctuate up
to 5 feet (1.5 m)from winter to summer,indicating a
free draining material.
The hydrologic regime shows summer peak flows in the
area reaching approximate Elevation 1440 feet (432 m)
at the north of Tsusena Creek.This elevation corre-
sponds with the limit of scoured and un vegetated
river bank.The estimated 50-year flood level is
approximately 1473 feet (442 m).
The underlyi ng bedrock overl ain by a sequence of
bouldery till,river and floodplain gravels and
sands.As in the case of Borrow Site 0,the grain
size distribution in Site E varies from boulders to
fine silt and clay.Within this wide range of soil
types,fi ve disti nct soil gradations (A through E)
can be delineated.However,the complex depo~itional
history and the limited exploration performed in this
area does not allow for ready correlation of these
soil types over the site.Generally,however,the
finer silts and sands are found in the upper five
feet of the deposit.Several abandoned river
channel s of ei ther the Tsusena Creek or the Su si tna
Ri ver cross-cut the si teo The i nfill i ng and cross-
cutting of these streams and rivers through the site
has resulted in a complex heterogeneous mixing of the
materials.Exploration indicates that,although the
five principal soil types are persistent within the
site,they vary in depth from near surface to
approximately 40 to 70 feet (12 m to 21 m).
No permafrost has been encountered in the borrow
site,probably because the site has a south-facing
exposure and has a continuous thawing effect caused
by the flowing river.Seasonal frost,up to 3 to 6
feet (1 to 2 m)deep,was observed in test pits that
encountered ground water (mid-March 1981)and up to
at least 13 feet (4 m)in pits on the northwest side
of the site that did not intercept the ground water
table.In areas of shallow ground water,the frost
was almost exclusively confined to the upper shallow
sand and silt layers,while dry gravels showed deeper
frost penetration.Annual frost penetration may be
2.5 -Borrow Site Alternatives
assumed to be about 3 to 6 feet (1 to 2 m)in silty
or clayey soils and at least 11 feet (3.3 m)in loose
dry gravels.
-
(iii)Reserves
Quantities were calculated on the basis of known and
inferred depos its above and below the current ri ver
regime.Assuming an overall surface area of approxi-
mately 750 to 800 acres (188 to 200 ha),the esti-
mated quantity of material above river elevation is
34 mcy (26 mcm).An additional volume ·of 52 mcy (40
mcm)is available below river elevation assuming a
total maximum depth of excavation of 125 feet (37 m)
in the southwest corner of the borrow site,decreas-
ing to a minimum of 20 feet (6m)in the northeast
corner.
Approximately 80 percent of the i denti fi ed materi al
in the borrow site is within the floodplain area,10
percent in the hillside terraces,and 10 percent in
the Tsusena Creek segment.
-
Average stripping is estimated at one foot of vegeta-
tion and 3 to 4 feet (l to 1.3 m)of fine-grained
material.
(iv)Engineering Properties
The soi 1 uni ts A through E range from coarse sandy
gravel through gravelly sand,silty sand,cobbles and
boulders,silty sand and silt.Several of these
material units correlate well with the material in
Sites I and J.Moisture contents for the silts range
from 25 to 30 percent;sand from 4 to 15 percent;and
gravels from 1 to 5 percent.The percentage of mate-
rial over 6 inches is roughly estimated at 10 percent
with the over-12-inch estimated at 5 percent.
Selective mining may be possible to extract particu-
1 ar types of material.Further detail ed i nvesti ga-
_tions in this area will be required to accurately
define the location and continuity of stratigraphic
units.
(v)Envi ronmental
This area is vegetated primarily with spruce forests.
r-Except for the area near the mouth of Tsusena Creek,
E-10-93
2.5 -Borrow Site Alternatives
it is not an environmentally sensitive area.
Chapter 3 of Exhibit E outlines mitigation techniques
which will be used to reduce the impacts to the
Tsusena Creek area.
(f)Borrow Site F
(i)Proposed Use
Borrow Site F was identified by the COE as a poten-
tial source of filter material for the main dam.
Preliminary work performed by the COE showed the site
to have limited quantities of material spread over a
1arge area.For this reason,Borrow Site E became
the preferred site,with Borrow Site F being consid-
ered as an alternative source for construction mate-
ri al for access roads,runways,and camp construc-
tion.
(ii)Location and Geology
Borrow Site F occupies the midd1e stretch of Tsusena
Creek from just above the high waterfall to north of
Clark Creek where it abuts Borrow Site C.The north-
east portion of the valley is confined by the flank
of Tsusena Butte and·its talus slopes.The vegeta-
tion in the area is mixed spruce and tundra,with
isolated areas of undergrowth and alders.Ground
water is expected to be near surface.Limited perma-
frost is likely to be encountered in north-and
west-facing exposures but is expected to thaw readily
when exposed during summer months.Deposits above
stream 1evel are expected to be fai rly well drai ned
with lower areas saturated.
Limited test pits indicate the material in Borrow
Site F is the same as that in Borrow Site C.The
depth of clean sands and gravels is estimated to be
approximately 20 to 30 feet (6 to 9 m),ranging from
a shall ow 5 feet (1.6 m)to a maximum of 40 feet
(12 m).The area consists of a series of gravel bars
and terraces extending up to 1500 feet (450 m)away
from the stream.
(iii)Reserves
No detailed topography was obtained for the site;
however,assuming a conservative depth of 20 feet
(6 m)of material,a total volume of approximately 15
to 25 mcy (11 to 19 mcm)is likely available.
E-10-94
,.,...
I
I
2.5 -Borrow Site Alternatives
Additional investigation in this area will be re-
quired to confirm these volumes.
(iv)Engineering Properties
Test pits excavated by the COE snow gravelly sand
overlain by a very thin silt and sandy silt cover.No
detailed testing was performed on this material.
(h)Borrow Site H
(i)Proposed Use
Borrow Site H has been defined as an alternative site
.-to Borrow Site 0 for impervi ous and semi pervi ous
material.
I~
-
-,
(ii)Location and Geology
The topography of Borrow Site H is generally rolling,
sloping towards the Susitna River.Elevations range
from 1400 feet to 2400 feet (420 m to 720 m)across
the site and average about 2100 feet (630 m).Most
of the site is covered by swamps and marshes,indica-
ting poor drainage.The vegetation consists of thick
tundra,muskeg,alder,and underbrush growth.
Ground water and surface water are perched on top of
impervious material with nUinerous seeps and ponded
surface water.The extensive coverage of spruce
trees may be indicative of a degrading permafrost
area.A large ice deposit exists in a slump exposure
on the west end of the site.The deposit and asso-
ciated solifluction flow with a multiple regressive
headwall are approximately 100 to 150 feet (30 to
45m)across.
Of the eight auger holes drilled in the site,six
encountered permafrost at depths ranging from 0 to 14
feet (0 to 4.2 m)in depth.All the holes but one
showed the water table at or near the surface.
The site stratigraphy consists of an average of 1.5
feet (0.5 m)of organics,underlain by 1.5 to 4.5
feet (0.5 m to 1.5 m)of brown sand or silt material
with traces of organics.Below this upper material,
most of the holes show mixed silt,s'andy silt,and
sandy clay to depths of 6 to 13 feet (1.8,to 3.9 m),
which in turn is underlain by zones of gravels,
gravelly sand,and mixed silts with sand and gravel.
E-10-95
2.5 -Borrow Site Alternatives
A color change from brown to gray occurs at depths of
6 to 28 feet (1.8 to 8 m).Insufficient data exist
to allow for detailed stratigraphic correlation
across the site.
(iii)Reserves
The quantity estimate has assumed a relatively homo-
geneous mix of material over a surface area of 800
acres (320 ha),with 5.5 feet (1.6 m)of stri ppi ng
required to remove organics and clean silts and
sands.Assum ing an est imated usable th i ckness of 32
feet (9.6 m)(based on dri 11 ing data),approximately
35 mcy (26 mcm)of material is available from this
site.
(iv)Engineering Properties
A detailed assessment of the grain size distribution
shows three distinct gradation groupings (A through
C).Gradation A denotes a gravelly sand,character-
ized by less than 40 percent fines and a significant
fraction exceeding 3/4 inch;B is a silty sand with-
out the generally coarser fraction;and C is a silt
unit which is generally less than 1 inch in maximum
particle size and contains in excess of 40 percent
fines.
In conclusion,Borrow Site H material is considered
suitable for use as impervious and semipervious fill.
However,problems such as wet swampy conditions,
permafrost,and the lengthy haul distance to the site
may affect the potential use of this site as a borrow
source.
(v)Environmental
This area is spruce and mixed forests.Raptor nests
on c1 iffs along Fog Creek and known archaeological
sites exi st withi n the area.These reasons,along
with its considerable distance from Watana Dam,con-
tributed to its classification as a non-primary
site.
(i)Borrow Sites I and J
(i)Proposed Use
Reconnaissance mapping was performed within a 10-mi1e
(16 km)radius of the damsite to locate potential
,F"""I
.....
r
l
.....
-
2.5 -Borrow Site Alternatives
sources of free-draining gravels for use in the dam
shell.The 1 arge vol ume needs of thi s materi al
requires that the source be relatively close to the
damsite and in an area that would minimize environ-
mental impacts during borrowing operations.As a
result,the Susitna River valley alluvium was deli-
neated as a potential borrow source.
(ii)Location and Geo"'logy
A seismic refraction survey performed across the
river channel indicated large quantities of sands and
gravel within the river and floodplain deposits both
upstream and downstream from the damsite.
Borrow Site I extends from the western limits of
Borrow Site E downstream for a distance of approxi-
mately 9 miles (14 km),encompass"ing a wide zone of
terrace and floodplain deposits.
Borrow Site J extends upstream from the damsite for a
distance of approximately 7.6 miles (12.2 km).The
site area extends from river bank to river bank and
includes several terraces and stream deltas.
Borrow Sites I and J are fully within the confines of
the Devil Canyon and Watana reservoi rs,respec-
tively.
Both sites are in an active fluvial environment.
Borrow Site J is flanked by bedrock,talus and till-
covered valley walls;while Borrow Site I includes
extens i ve te rraces extendi ng several hundred feet up
the valley walls above river level.
(iii)Reserves
For purposes of volume calculation,it was assumed
that all materials with seismic velocity of 6500 ft/s
represented suitable gravel deposits.Materi al s with
velocities higher than 6500 ft/s were assumed to be
either too boul dery or dense.Not i ncl uded in the
estimate were:
-The river material between the two sites;
-Materi al between the west bounda ry of Site J and
the downstream area of the damsite;and
-The section from the damsite to Borrow Site E.
E-10-97
2.5 -Bdrrow Site Alternatives
This last area was considered to require excessive
dredging and could likely affect the hydraulics of
the tailwater.
An active slope failure was identified near Borrow
Site H.If further studies show that the excavation
of river material beneath this slide may result in
slope failure,then this section of alluvium will be
left in place.In summary,a total of 125 mcy
(95 mcm)of material were estimated in Borrow Site I,
extending a Idistance of 8.5 miles (13.6 km)down-
stream and 75 mcy (57 mcm)in Borrow Site J over a
distance of 7 miles (11 km)upstream.
(iv)Engineering Properties
Three bas ic g radat ions are present withi n the two
sites.These are fine-grained silty sand,sand,and
gravel.The fine silty sand fraction was encountered
in 25 percent of the test pits and ranged in thick-
ness from 6 inches (15 em)to 6 feet (1.8 m).The
second gradation is a sand which varies from a well-
sorted clean sand to a gravelly,poorly sorted sand.
Thi s type of materi al was encountered in only 15
percent of the 22 pits,and where present,underlies
the silt layer with an average thickness of about 4
feet (1.2 m).The bulk of the samples are of a
moderately sorted gravel mixed with from 20 to 40
percent of sand and silt with less than 5 percent
silt and clay size fraction.
(v)Environmental
Borrow sites I and J are fully within the limits of
the reservoir.Since these areas will be flooded,no
additional impacts were identified.Use of these
areas will contribute to a lessening of project
impacts.
(j)Quarry Site L
(i)Proposed Use,
Quarry Site L has been i dentifi ed as a source for
cofferdam shell material.
(ii)Location and Geology
Quarry Site L is located 400 feet (120 m)upstream
from the proposed upstream cofferdam on the south
-
2.5 -Borrow Site Alternatives
bank.The site is a rock knob immediately adjacent
to the river which is separated from the main valley
walls by a topographically low swale that has been
mapped as a relict channel.
The rock in the quarry area is diorite along the
western portion of the knob with andesitic sills or
dikes found farther upstream.The rock exposure
facing the river is sound with very few shears or
fractures.The vegetation is heavy brush with tall
deciduous trees on the knob and alders with brush in
the swal e to the south.Li ttl e surface water is
present on the knob;however,the low lying swale is
marshy.Permafrost may be expected to be present
throughout the rock mass.
Quarry Site L lies opposite liThe Fins"feature which
is exposed on the north abutment;however,extensive
mapping in this area shows no apparent shearing or
fracture that could be correlative with the extension
of this feature.
(iii)
(i v)
Reserves
Because of limited bedrock control,the site has been
delineated into two zones for estimating reserves.
Zone I del imits the total potential reserves based on
assumed overburden and rock vol umes,whil e Zone I I
identifies that volume of rock that,with a high
degree of confidence,is known to be present.Based
on field mapping and airphoto interpretation,the
total usable volume of material has been estimated to
be 1.3 mcy (1 mcm)for Zone I and 1.2 mcy (0.9 mcm)
for Zone II,over an area of 20 acres (8 ha).
Engineering Properties
No testing was performed on rock samples for Quarry
Site L.However,based on field mapping,it appears
that the rock properties and quantities will be simi-
lar to those at the damsite.
--(v)Envi ronmental
This area is totally within the mlmmum pool of the
Watana reservoir.This lessened environmental
impacts and contributed to its selection as a primary
site.
E-10-99
2.5 -Borrow Site Alternatives
2.5.2 -Devil Canyon Borrow Sites
One borrow site and one quarry site were identified for the Devil
Canyon study (Figure E.10.14).Borrow Site G was investigated as
a source for concrete aggregate and Quarry Site K for rockfill.
Despite detailed reconnaissance mapping around the site,no local
source for impervious or semipervious material could be found.
As a result,Borrow Site D from the Watana inventory has been
delineated as the principal source for this material.Further
investigations may identify a more locally available source.The
following sections provide a detailed discussion of the borrow
and quarry sites for the Devil Canyon development.
(a)Borrow Site G
(i)Proposed Use
Borrow Site G was previously identified by the 'USBR
and investigated to a limited extent by the COE as a
primary source for concrete aggregate.Because of
its close proximity to the damsite and apparent large
vol ume of material,it became a principal area for
investigation.
(ii)Location and Geology
Borrow Site G is located approximately 1000 feet
(300 m)upstream from the proposed damsite.The area
delineated as Borrow Site G isa large flat fan or
terrace that extends outward from the south bank of
the river for a distance of approximately 2000 feet
(600 m).The site extends for a distance of approxi-
mately 1200 feet (360 m)east-west.Cheechako Creek
exits from a gorge and discharges into the Susitna
Ri ver at the eastern edge of the borrow site.The
fan is generally flat-lying at Elevation 1000 feet
(300 m),approximately 80 feet (24 m)above river
level.Higher terrace levels that form part of the
borrow site are found along the southern edge of the
site above Elevation 1100 feet (330 m).
Vegetation is scattered brush with mixed deciduous
trees found on the fl oodpl a in and fan port ions.On
the southern hillside portion of the borrow site,
hea vy vegetat ion is evi dent wi t h dense trees and
underbrush.The ground cover averages up to 0.5 feet
(0.1 m)in thickness and is generally underlain by
1 foot (0.3 m)to a maximum of 6.5 feet (1.9 m)of
silts and silty sands.This silt layer averages 1.5
E-IO-IOO
-
2.5 -Borrow Site,Alternatives
feet (0.5 m)thick on the flat-lying deposits,and up
to 2 feet (0.6 m)thick on the hillsides above Eleva-
tion 950 feet (285 m).
No ground water was encountered in any of the explor-
ations.The high permeability of the material pro-
vides for rapid drainage of the water to the river.
Annual frost penetration can be expected to be from 6
to 15 feet (1.8 to 4.5 m).No permafrost has been
encountered in the area.
The borrow material has been classified into four
bas ic types,based on the i nterpretat i on of fi e 1d
mapping and explorations:Susitna River alluvial
gravel s and sand,ancient terraces,Cheechako Creek
alluvium,and talus.
The 1arge fan deposits are a combi nation of rounded
alluvial fan and river terrace gravel s composed of
various volcanic and metamorphic rocks and some sedi-
mentary rock pebbles.This material is well-washed
alluvial material.
(iii)Reserves
The quantities of fine sands and gravels above river
level have been estimated to be approximately 1.1 and
1.9 mcy (0.84 and 1.4 mcm),respectively.Additional
quantities could be obtained by excavating below
river level.The quantity of material from the
ancient terrain is tentatively estimated to be
approximately 2 mcy (1.5 mcm).This,however,has
been based on an inferred depth to bedrock.If bed-
rock is shallower than estimated,this quantity would
be less.
Cheechako Creek all uvium is estimated at 1.1 mcy
(0.84 mcm),while the quantity of talus is 55,000
mcy (41,800 mcm).Talus quantities are too small to
warrant consideration as a borrow material.
An estimate of the total quantity of borrow material
is about 3 mcy (2.2 mcm),with an additional 3 mcy
(2.2 mcm)potentially available from inferred resour-
ces.The increase in river level caused by diversion
during construction may affect the quantity of avail-
abl e materi a 1 from t hi s site.Therefore,further
work will be required in subsequent studies to
accurately determine available quantities,methods,
and schedules for excavation.
E-10-101
2.5 -Borrow Site Alternatives
(iv)Engineering Properties
The deposit is a gravel and sand source composed of
rounded granitic and volcanic gravels,with a few
boulders up to 3 feet (0.9 m)in diameter.Deterior-
ated materials comprise about 8 to 10 percent of the
samples.
Testing performed by the USBR indicates that about 2
to 4 percent of the material was considered adverse
material for concrete aggregate.
Two distinct grain sizes are found in the site:1)
from the auger holes,a fairly uniform,well sorted
coarse sand with low fine content;and 2)from the
test trenches,a fairly well-graded gravelly sand
averaging 10 percent passing No.22 sieve.The
principal reason that the auger drilling did not
encounter the coarser material is 1 ikely reflective
of the sampl i ng technique where the auger sampl ing
could not recover the coarser fractions.
A finer silty layer overlies much of the borrow site.
Samples from the higher elevations are more sandy
than those from the fan area.
Based on observed conditions,the grain sizes from
the trenches are considered more representative of
the material in Borrow Site G at depth,while the
finer fraction represents the near surface material.
(v)Environmental
Since this area is within the Devil Canyon impound-
ment,there will be no additional impacts.
(b)Quarry Site K
(i)Proposed Use
Quarry Site K was identified during this study as a
source for rockfill for the construction of the pro-
posed saddle dam on the south abutment.
(ii)Location and Geology
The proposed quarry site is approximately 5300 feet
(1590 m)south of the saddle damsite,at approximate
Elevation 1900 feet (570 m).The site consists of an
E-I0-I02
,",
.f"'"
I
I~
2.5 -Borrow Site Alternatives
east-west face of exposed rock cl iffs extending to
200 feet (60 m)in height.Vegetation is limited to
tundra and scattered scrub trees.
Drainage in the area is excellent with runoff around
the proposed quarry site being diverted to the north
and east toward Cheechako Creek.The ground water
table is expected to be low and confined to open
fractures and shears.
The bedrock is a white-gray to pink-gray,medium-
grained,biotite granodiorite simila~to that at the
Watana damsite.The rock has undergone slight meta-
morphism and contains inclusions of the argillite
country rock with local gneissic texture.The rock
is generally massive and blocky,as evidenced by
1arge,blocky,tal Lis slopes at the base of the
cliffs..
The rock is probably part of a 1 arger bathol ith of
probable Tertiary age which has intruded the sedi-
mentary rocks at the damsite.
-
-i
-
(i i i )Reserves
The limits that have been defined for the quarry site
have been based on rock exposure.Additional mate-
rial covered by shallow overburden is likely to be
available,if required.However,s"ince the need for
rockfill is expected to be small,no attempt was made
to extend the quarry si te to its maximum 1 imits.The
primary quarry site is east of Cheechako Creek.This
area was selected primarily because of its close
proximity to the damsite and high cl iff faces which
are conduci ve to rapi d qua rryi ng.The low area west
of the site was not included because of possible poor
qual ity sheared rock.A secondary (backup)quarry
source was delineated west of the primary site.
Because of the extensive exposure of excellent qual-
ity rock in this area,additional exploration was not
considered necessary for this study.
The approximate volume of rock determined to be
available in the primary site is about 2.5 mcy per 50
feet (1.5 mcm per 15 m)of excavated depth,or
approximately 7.5 mcy (5.7 mcm)within about a
30-acre (12 ha)area.The alternative backup site to
the west of Quarry K has been estimated to contain an
additional 35 mcy (27 mcm)for 150 feet (45 m)of
depth,covering some 145 acres (58 ha).
E-IO-I03
2.5 -Borrow Site Alternatives
(iv)Engineering Properties
The granodiorite was selected over the more locally
available argillite and graywacke because of the
uncertainty about the durability of the argillite and
graywacke under severe climatic conditions.
The properties of the granodiorite are expected to be
similar to those found at the Watana damsite.
Freeze-thaw and wet-dryi ng (absorpti on)tests
performed on rock types simil ar to those found on
Qua rry K by the COE exhi b ited freeze-thaw losses of
<1 percent at 200 cycles and absorption losses of 0.3
percent.Both tests showed the rock to be extremely
sound and competent.
(v)Environmental
This area is primarily a cliff site.Only small
amounts of materi ala re expected to be needed so
impacts should not be great.
E-10-104
r--,
r
3 -ALTERNATIVE OPERATING SCENARIOS
3.1 -Project Operation and Flow Selection
3.1.1 -Simulation Model and Selection Process
A multireservoir energy simulation model was used to evaluate the
optimum method of operating the Susitna Hydroelectric Project for
a range of post project flows at the Gold Creek gaging station 15
miles (24 km)downstream of the Devil Canyon damsite.
The simulation model incorporates several featues which are
satisfied according to the following hierarchy:
-Minimum downstream flow requirements;
-Minimum energy demand;
-Reservoir operating rule curve;and
-Maximum usable energy level.
The physical characteristics of the two reservoirs,the opera-
tional characteristics of the powerhouses,and either the monthly
or weekly average flow at each damsite and Gold Creek for the
number of years to be simulated are required as input to the
simulation program.The program operates the two reservoirs to
produce the maximum possible average annual usable energy while
satisfying the criteria listed above.First,the minimum flow
requirement at Gold Creek is satisfied.Next,the minimum energy
requirement is met.The reservoir operating rule curve is
checked and if "extra water"is in storage,the "extra water"is
used to produce additional energy up to the maximum usable energy
level.There is a further consideration that the reservoir
cannot be drawn below the maximum allowable drawdown limit.The
energy produced,the flow at the damsites and at Gold Creek,and
the reservoir levels are determined for the period of record
input to the model.
The process that led to the selection of the flow scenario used
in this license application includes the following steps:
-Determination of the pre-project flows at Gold Creek,Cantwell,
Wgtana,and Devil Canyon for 32 years of record;
Sel ecti on of the range of post project flows at Gol d Creek to
be included in the analysis;
-Selection of timing of flow releases to match downstream
fishery requirements;
-Determination of the energy produced and net benefits for the
seven flow release scenarios being studied;
E-1O-105
3.1 -Project Operation and Flow Selection
-Consi derat i on of the i nfl uence of i nstream flow and fi shery
needs on the selection of project operational flows;
-Select i on of a range of acceptable flows based on economi c
factors;fishing,and instream flow considerations;and
-Selection of the maximum drawdown at Watana.
A summary discussion of the detailed analysis is presented in the
following paragraphs.
3.1.2 -Pre-project Flows
As discussed in Section2.2.1 of Chapter 2,the 32-year discharge
record at Gold Creek was combined with a regional analysis to
develop a 32 year record for the Cantwell gage near Vee Canyon on
the upper end of the proposed Watana reservoi r.The flow at
Watana and Devil Canyon was then calculated using the Cantwell
fl ow as the base and adding an incremental flow proport i ona 1 to
the additional drainage area between the Cantwell gage and the
damsites.
The avai 1abl e-32 year record was consi dered adequate for deter-
mining a statistical distr"ibution of annual energies for each
annual demand scenario considered,and hence,it was not con-
sidered necessary to synthesize additional years of record.
The 32-years of record contai ned a low flow event (water year
1969)with a recurrence interval .of approximately 1000 years as
illustrated in Figure E.2.23.This water year (WY)was adjusted
to reflect a low flow frequency of 1:30-years since a 1:30 year
event represents a more reasonable return peri od for fi rm energy
used in system reliability tests.
Although the frequency of the adjusted or modified year is a
1:30-year occurrence,the two year low flow frequency of the mod-
ified WY 1969 and the succeeding low flow WY 1970 is approxi-
mately 1:100 years.The unmodified two year low flow frequency
is approximately 1:250 years.This two-year low flow event is
important in that,if the reservoir is drawn down to its minimum
level after the first dry year,the volume of water in storage in
the reservoi r at the start of the winter season of the second
year of the two year sequence will be insufficient to satisfy the
minimum energy requirements.Hence,the modified record was
adopted for use in the simul ation studies (Refer to Section 3.4
of Chapter 10 for the effect of thi s change on fi rm energy and
average energy).
The 1:30 year annual volume was proportioned on a monthly basis
according to the long term average monthly distribution.This
E-10-106
-
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3.1 -Project Operation and Flow Selection
increased the WY 1969 average annual discharge at Gold Creek 1600
cfs,from 5600 cfs to 7200 cfs and the average annual discharge
at Gold Creek for the 32 years of record by 0.5 percent.The re-
sulting monthly flows at Watana,Devil Canyon,and Gold Creek are
presented in Tables E.I0.25,E.I0.26,and E.I0.27.
3.1.3 -Project Flows
(a)Range Flows
A range of proj ect ope rat i ona 1 target flows from 6000 to
19,000 cfs at Gold Creek were analyzed.The flow at Gold
Creek was sel ected because it was judged to be representa-
tive of the Devil Canyon-to-Talkeetna reach where downstream
impacts will be the greatest.Additionally,the flows can
be directly compared with the 32 years of discharge records
at Gold Creek.
The range of project flows analyzed included the operational
flow that would produce the maximum amount of usable energy
from the project,neglecting all other considerations (re-
ferred to as Case A)and the operational flow which would
have resulted in essentially no impact on the downstream
fishery during the anadromous fish spawning period (referred
to as Case D).Between these two end points,five add;'..
tional flow scenarios were analyzed.
In Case A,the minimum target flow at Gold Creek for the
month of August and the first half of September was estab-
lished at 6000 cfs.Flow was increased in increments of
2000 c fs for the August-September time peri od,thereby es-
tablishing the target flow for Cases AI,A2,C,Cl,and C2.
The August-September flow for Case D was established at
1~,OOO cfs.The resulting seven flow scenarios were ade-
quate to change in project flow requirements.The monthly
minimum target flows for all seven flow scenarios are pre-
sented in Table E.2.34 and Figure E.2.130 in Chapter 2.
,-.
I
-
(b)Timing of Flow Releases
In the reac h of the Sus itna Ri ver between Talkeetna and
Devil Canyon,it is perceived that an important aspect of
maintaining natural sockeye'and chum salmon reproduction is
providing access to the slough spawning areas hydraulically·
connected to the mainstem of the river.Access to these
slough spawning areas is primarily a function of flow (water
level)in the main channel of the river during the period
when the salmon must gai n access to the spawni ng areas.
Field studies during 1981 and 1982 have shown that the most
critical period for access is August and early September.
E-I0-I07
3.1 -Project Operation and Flow Selection
Thus,the proj ect operat i ona 1 flow has been schedul ed to
satisfy this requirement;i.e.,the flow will be increased
the 1 ast week of July,hel d constant duri ng August and the
first two weeks of September and then decreased to a level
specified by energy demands in mid September.Alternative
modes that rel ease the same amount of water but as short-
term augmented flows are also being evaluated.
3.1.4 -Energy Production and Net Benefits
The reservoir simulation model was run for the seven flow cases.
Monthly energies were determined for the 32 years of simulation
assumi ng the year 2002 energy demands for Watana operation and
2010 for Watana/Devil Canyon operation.It was assumed that the
distribution of energies obtained in the year 2002 simulation
would apply for years 1993 to 2002 and the 2010 simulation would
apply for the years 2002 to 2051.Beyond yeard 2010,the demand
was assumed to remain constant.
To determine the net economic value of the energy produced by the
Susitna Hydroelectric Project,the mathematical model commonly
known as OGP 5 (Optimized Generation Planning Model,Version 5),
was used to determi ne the present worth val ue (1982 doll ars)of
the long-term (1993-2051)productions costs (LTPWC)of supplying
the Railbelt energy needs by various alternative means of genera-
tion.A more detailed description of the OGP 5 model is con-
tained in Exhibit B,Section 1.5.The analysis was performed for
the "best thermal option"as well as for the seven flow scenarios
for operating Susitna.The results are presented in Table E.2.35
in Chapter 2 of Exhibit E.
The net benefit presented in Table E.2.35 is the di fference be-
tween the LTPWC for the "best thermal opt i on"and the LTPWC for
the various Susitna options.In Table E.2.35,Case A represents
the maximum usable energy option and results in a net benefit of
$1234 mi 11 i on.As fl ow is transferred from the wi nter to the
August-September time period for fishery and instream flow miti-
gation purposes,the amount of usable energy decreases.This de-
crease is not significant until the flow provided at Gold Creek
during August reaches the 12,000 to 14,000 cfs range.For a flow
of 19,000 cfs at Gold Creek,a flow scenario that represents min-
imum downstream fishery impact,approximately 46 percent of the
potential project net benefits have been foregone.
3.2 -Instream Flow and Fishery Impacts of Flow Selection
3.2.1 -Susitna River Fishery Impacts
As noted earlier,the primary function controlled by the late
summer flow is the ability of the salmon to gain access to their
E-10-108
~~~..~--~~----~._-~~_._--_._-~--
r
3.2 -Fishery and Instream Flow Impacts
traditional slough spawning grounds.Instream flow assessment
conducted during 1981 (the wettest July-August on record)and
1982 (one of the driest July-August on record)has indicated
that for flows of the Case A magnitude,severe impacts would oc-
cur which cannot be mitigated except by compensation through
hatchery construction and operation.
For flows in the 12,000 cfs range (flows similar to those that
occurred in August,1982)the salmon can,with difficulty,obtain
access to their spawning grounds.To insure that the salmon can
always obtain access to spawning areas during a flow of 12,000
cfs,a series of habitat alteration techniques are incorporated
into the mitigation plan presented in Section 2.4.4 of Chapter 3,
Exhibit E.Because Case A,AI,and A2 flow scenarios are not ex-
pected to allow habitat alteration to mitigate the impacts caused
by the changed flows,the lowest acceptable flow range was estab-
lished as approximately 12,000 cfs (Case C)at Gold Creek during
August.
3.2.2 -Tributary Fishery Impacts
Since three salmon species (chinook,coho,and pink)use the
clear water tributaries for essentially all their spawning activ-
ities and chum use tributaries for most of their spawning,a se-
cond primary concern relative to post project flow modifications
is maintaining access into the tributaries:i.e,the mouth of
the tributaries cannot be permitted to become perched as a result
of reduced mai nstem stages.However,a tri butary I s response to
perching is a function of its flow and the size of bed material
at its mouth,neither of which will be affected by the post proj-
ect change in mainstem flow.Thus,perching of tributaries is
more dependent on tri butary characteri st ics than on the opera-
tional scenario selected.
Recent studies (RM&1982)have shown that for post project flows,
most of the tributaries will not become perched.However,eight
tributaries showed potential for perching (see Table E.2.in Chap-
ter 2).Of these three named tributaries that show a potential
for perching,Little Portage Creek (RM 117.8),Deadhorse Creek
(RM 121.0),and Sherman Creek (RM 130.9),and two unnamed tribu-
taries are not considered to be significant salmon streams (ADF&G
comments on the November 15,1982 Draft Exhi bit E).If one of
the three tributaries that provide some spawning potential does
become perched,the entrance to the stream wi 11 be regarded so
that salmon can gain access to traditional spawning areas.
E-10-109
3.3 -Other Instream Flow Considerations
3.3 -Other Instream Flow Considerations
3.3.1 -Downstream Water Rights
Water rights in the Susitna basin are minimal (see Chapter 2).
Therefore,since all flow scenarios provided more than enough
flow to meet downstram water rightw,it was not a factor in
minimum flow selection.
3.3.2 -Navigation and Transportation
As discussed in Chapter 2,an impact on navigation during the
open water period could occur in the Sherman area at Gold Creek
flows of 6000 cfs.However if navigation problems do develop,
mitigation measures will insure that navigation is not affected.
Therefore since minimum flows in May through September for Cases
C,C1, C2,and Dare 6000 cfs and since mitigation measures will
be implemented if necessary,navigation was not considered to be
a factor among Cases C,C1, C2,and D.Cases A,AI,and A2 do
have minimum flows that are less than 6000 cfs and thus the mini-
mum flows for these cases could lead to increased navigational
difficulty.From a navigation perspective Cases A,AI,and A2
were less acceptable than Cases C,C1,C2,and D.
3.3.3 -Recreation
Recreation on the Susitna River is closely associated with navi-
gation and transportation and the fishery resource.Since the
Susitna River below Devil Canyon will be navigable during the
summer months at all minimum flow scenarios,this aspect of rec-
reation was not a factor in the flow selection process.However,
from a fishery perspective,if a fishery habitat is lost,this
could reduce the recreational potential of the fishery.At the
Case A,AI,and A2 flows,there is some impact on the sockeye and
chum fishery.For flows equal to or greater than Case C flows,
the fi shery impact can be mit i gated.Hence,Case C or greater
flows should be selected as the minimum operational flow based on
recreational considerations.
The summer water quality improvement in turbidity,which will en-
hance the recreation potential of the area would be the same for
all cases and not be a factor in flow selection.
3.3.4 -Riparian Vegetation and Wildlife Habitat
Riparian vegetation is affected by one or more of the following:
floods,freezeup,and spring ice jams.Minimum flow selection
for the cases considered is unrelated to any of these factors.
Hence,riparian vegetation effects were not considered in minimum
project flow selection.
E-10-110
r--··
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3.4 -Operational Flow Scenario Selection
Riparian vegetation is likely affected by the freezeup process,
ice jams,and spring floods in the Devil Canyon to Talkeetna
reach (Section 2.6.5 in Chapter 2).In the Talkeetna to Yentna
and Yenta to Cook Inlet reaches,spring flooding likely has the
major impact on riparian vegetation.Hence,since spring floods
in the'Susitna River will be reduced from Watana to Cook Inlet
(Section 4.'1.3 in Chapter 2),it may be desirable to mainta"in
riparian vegetation by simulating spring floods for a short per-
iod of time.However,the spring runoff storage is a key element
of the project.Large releases for even a few days would have
severe economic impact on the project.Hence,no minimum flood
discharges were considered.
If summer floods occur and have an effect on riparian vegetation,
there would essentially be no difference between the flow cases.
This is because minimum flows would not govern if the reservoir
is full,inflow will be set equal to outflow up to the capacity
of the release facilities.
3.3.5 -Water Quality
The pre-and post-project downstream summer temperatures will be
essentially the same for all cases although the lower discharges
would exhibit a faster temperature response to climatic changes.
The waste assimilative capacity for all cases will be adequate at
a flow of 6000 cfs.All other water quality parameters essenti-
ally be the same for all flow scenarios.
3.3.6 -Freshwater Recruitment to Cook Inlet
The change in salinity in Cook Inlet will essentially be the same
for all seven flow scenarios although the higher minimum flows
(Case D)will exhibit a salinity pattern closer to the natural
condition.This was not considered significant in the flow
selection process.
3.4 -Operational Flow Scenario Selection
Based on the economic analysis discussed above,it was judged that,
while cases A,AI,and A2 flows produced essentially the same net bene-
fit,the loss in net benefits for Case C is of acceptable magnitude.
The loss associ ated with Case CI is on the borderl i ne between accept-
able and unacceptable.However,as fishery and instream flow impacts
(and hence mitigation costs associated with the various flow scenarios)
are refined (see Table £.3.39 in Chapter 3)the decrease in mitigation
costs associated with higher flows does not warrant selecting a higher
flow case such as Cl.The loss in net benefits assoc i ated with Cases
C2 and 0 are considered unacceptable and the mitigation cost reduction
associated with these higher flows will not bring them into the accept-
able range.
3.5 -Maximum Drawdown Selection
3.5 -Maximum Drawdown Selection
The Watana reservoi r is used to red i st ri bute the flow from the summer
runoff period to the winter high energy demand period.The maximum
reservoi r drawdown is used to produce fi rm energy duri ng a low flow
sequence which is usually one to two years in duration for the Susitna
River above Gold Creek.The drawdown of the Devil Canyon reservoir is
used either to provide the specified minimum downstream fishery flow
during August and early September or to produce firm energy in April or
early May during those years when the Watana reservoir has reached its
maximum drawdown limit.
During the Susitna Hydroelectric Feasibil ity Study (Acres 1982)the
maximum drawdown of the Watana reservoir for power generation purposes
was sel ected as 140 feet (42 m)and for the Devil Canyon reservoi r as
50 feet (15 m).The 140 foot (42 m)drawdown was determined to be op-
timal for the Case A operational flow scenario.However,the maximum
drawdown was re-eval uated for two reasons.As more flow is released
for instream flow purposes during the summer season,less live storage
volume is required on an annual basis to redistribute the remainder of
the summer runoff into the wi nter hi gh energy demand peri od.On the
other hand,during a low flow year,less flow is available for reser-
voir storage because of the additional downstream flow requirements.
The net effect may influence the maximum drawdown required and was
therefore reassessed.
In addition,in the Case A scenario presented in the Susitna Hydroelec-
tric Feasibility Study (Acres 1982),the maximum drawdown was required
for two years in the 32 year simulation period.For the other 30
years,the maximum drawdown was approximately 100 feet (30 m).There-
fore,the frequency of the two year low flow sequence was reexamined to
determi ne if it was too conservat i ve upon whi ch to base the max imum
drawdown.As discussed in Section 3.1.2,WY 1969 was modified to re-
flect a more representative planning period.
Then,taking into account the minimum downstream flow considerations,
the average annual and firm energy production,and the intake structure
cost,the reevaluation process resulted in the selection of 120 feet
(36 m)as the maximum drawdown for the Watana reservoir with the Case C
scenario.Because the Devil Canyon maximum drawdown is controlled by
technical considerations,the 50 foot (15 m)drawdown was not reconsi-
dered and has been retained as the limit for Devil Canyon.
The modified record had 1ittle effect other than on maximum drawdown
which is controlled by the minimum annual (or firm)energy production,
and vice versa.It has minimal effect on average flow,increasing the
flow at Gold Creek by one-half percent over the unmodified record.
Average annual energy increased by the same one-half percent.Project
operation differed from the unmodified record only during the two-year
low flow period and the succeeding one year recovery period.
E-10-112
!'''-'
~
I
-.
3.5 -Maximum Drawdown Selection
The downstream flow requirement at Gold Creek will be met at all times
unl ess both the Watana and Devi 1 Canyon resevoi rs are drawn down to
their minimum level and the natural flows at Gold Creek are less than
the flow requirement.The possibility of this occurring in the summer
months is remote.Even if a two-year low flow event with a recurrence
interva.l greater than 100 years occured,downstream flows would be pro-
vided at all times.Only during a late spring breakup,occuring after
a severe two-year low flow event when both reservoirs are drawdown to
their minimum elevation would there be a possibility of not meeting the
downstream flow requirement.
,--
4 -ALTERNATIVE ELECTRICAL ENERGY SOURCES
A detailed study of the Alaska Railbelt Generating Alternatives was
undertaken by Battelle Pacific Northwest Lab.Most of the information
in this section is taken from reports documenting that study (Battelle
1982).
4.1 -Coal-Fired Generation Alternative
Previous studies have indicated that alternative generating resources
available to supply power to the Railbelt region include use of the
Beluga coal fields.The economic and technical feas"ibility of
developing this resource and of the selection process utilized to
conclude the economic feasibility of Beluga coal,is discussed in
Exhibit B.
Information presented in this section was extracted from prev"ious
reports prepared in conjunction with studies of developing the Beluga
coal fields (CIRIjPlacer 1981,CIRIjPlacer 1981a,CED 1980 t
BattellejEbasco 1981).Because specifics of plant design and location
are not available t the existing environment is described for the
general area and impacts are discussed in generic terms only.
For purposes of this evaluation,an electrical generating plant with
total capacity of 400 MW was assumed.Coal would be strip-mined from
the Beluga fields,transported to the plants,and burned to produce
electricity.Treatment of waste streams t including air t water,and
solid waste t would occur at the site.Approximately 1.5 million tons
of coal per year would be burned.A construction camp would be built
near the site,and a permanent village maintained for mining personnel
and plant operators.
4.1.1 -Existing Environmental Condition
The Beluga coal fields are located approximately 50 to 60 miles
(80 to 96 km)southwest of Anchorage on the western side of Cook
Inl et.The coal fi el ds a re bordered by Cook Inl et on the east
and south,the Chakachatna River on the west,and the Beluga
River,Bel uga Lake t and Capps Glacier on the north (State of
Alaska 1972).
(a)Air Quality
Air quality in the Cook fulet and Beluga coal field area can
be described as good."The Cook Inlet Ai rQual ity Control
Region is designated as a Class II Attainment area for all
criteria pollutants.The Tuxedni National Wildlife Refuge
approximately 80 mil es (128 km)southwest of the project
area is a Class I Attainment area for all criteria of pol-
lutants.
E-10-115
4.1 -Coal-Fired Generation Alternative
(b)Topography,Geology,and Soils
The topography of the western shore of Cook Inlet is domina-
ted by high glaciated mountains dropping rapidly to a
glacial moraine/outwash plateau which slopes gently to the
sea.The outwash/moraine deposits begin at an elevation of
approximately 2500 feet (750 m)and drop to tidewater in 30
to 50 miles (48 to 80 km)(CIRI/Placer 1981).
The major geol ogi c feature of the area is the Ni kol ai
moraine which lies in contact with sedimentary Tertiary
rocks (CEO 1980).Most coals occur in the Tyonek Formation
of the Tertiary Kenai Group (Battelle 1978).The area is
geologically young with higher upland elevations consisting
of slightly to moderately modified glacial moraines and
associated drifts.
The lowland areas are mantled with glacial deposits and
overlaid by silt loam.
Soils are variable in the area.Generally,soils in the
southern porti on of the a rea are sandy but poorly dra i ned,
and soils in the west are well drained and dark,formed in
fine volcanic ash and loam.Soils in the east and northern
areas range from poorly drained fibrous peat to well-drained
loamy soil s of aci di c nature.
(c)Surface Hydrology
The three major river systems in the Beluga coal field area
are the Chakachatna,Beluga,and Chul i tna.The Chakachatna
is the largest,with headwaters in Chakachamna Lake and a
1620-square-mile (4292 km 2 )drainage area,and a length of
36 mil es (58 km).The Chul itna Ri ver begi ns near Capps
Glacier,flows 27 miles i45 km),and drains approximately
150 square m"iles (390 km).The Beluga River is 35 miles
in length and drains 930 square miles (2418 km 2 )(CEO
1980).
(d)Terrestrial Ecosystem
(i)Flora
Five major vegetative communities in the region are
the upland spruce-hardwood forest,lowland spruce-
hardwood forest,high brush,wet tundra,and alpine
tundra.
E-10-116
4.1 -Coal-Fired Generation Alternative
The upland spruce-hardwood forest is centered in the
southern and central porti ons of the Beluga area and
covers 40 percent of the area (CEO 1980).Thi s
forest is composed of paper birch,quaking aspen,
black cottonwood,and balsam poplar (CIRI/Placer
1981)•
The 1owl and spruce-ha rdwood forest covers approxi-
mately 35 percent of the area.Pure stands of bl ack
spruce are present.Other species include white
spruce,paper birch,quaking aspen,and blue berry.
The high brush community in the west central portion
of the Beluga district covers 15 percent of the land
area •.This type occupies a wide variety of soil
types and may occur as pure thickets in low-lying
areas.Principal species include sitka sider,rasp-
berry dogwood,and spirea (CIRI/Placer 1981;CEO
1980).
The wet tundra plant community occupies 7 percent of
the area in the extreme southwest port i on and along
the eastern boundary.The vegetative mat is domi-
nated by sedges and cottongrass,with scattered woody
and herbaceous pl ants.Pri nci pal speci es i ncl ude
willow,birch,labrador tea,grasses,and lichens.
The alpine tundra area occupies less than 3 percent
of the land area and occurs only at the higher eleva-
tions.This community comprises primarily low mat
plants,both woody and herbaceous.Principal species
include birches,willows,blueberry,rhododendron,
,and sedges.
(ii)Fauna
The area of the Beluga coal fields supports wildlife
population typical for this area of Alaska.Big game
in the areas include moose,black bear,and brown
bear.Both species of bear den in the area and uti-
lize the Selvon fishery as a food source (CIRI/Placer
1981).A major fall and winter concentration of
moose occurs in the high brush community in the west
central portion of the coal fields near the Chuitna
River.They are also found throughout the area
during other times of the year (CEO 1980).
E~1O-117
4.1 -Coal-Fired Generation Alternative
A high diversity of bird life is present in the area,
particularly during the fall and spring migration
peri ods.Active nesting sites of bald eagl es and
trumpeter swans occur on the Chuitna River and pere-
grine fal cons occur in the area (CIR IIPl acer).The
coastal areas are heavily utilized by waterfowl (CEO
1980).Harbor seals,Beluga whales,and other
species of marine mammals occupy Cook Inlet near the
study area.
(e)Aquatic Ecosystem
The cold,running waters of river and streams in the area
support both resident and anadromous fisheries.The Chuitna
River supports five species of salmon (pink,king,chum,
coho,and sockeye)pl us rainbow trout,Dolly Varden and
round white fish (CEO 1980).Nikolai Creek,Jo1s Creek,
Pitt Creek;and Stedatana Creek are al so known to support
anadromous fish populations.
(f)Marine Ecosystem
The Cook Inlet region just south of the Beluga coal fields
is a diverse area,with both aquatic and terrestrial habi-
tats.Intertidal and shallow subtidal habitats contain
broad expanses of gravel and sand and extensive areas of mud
flats.These areas show varying levels of productivity,
with the mud flat areas generally at low levels (CIRI/Placer
1981)).Dominant fauna present include pelecypods and poly-
chaete worms.The area of gravel and sand support moderate
densities of amphipods and isopods.
The Cook Inlet area is al so important to commercial and
sport fisheries.Four species of salmon and halibut utilize
this area and are harvested on a commercial basis,as are
herring,shrimp,and crabs.Commercial salmon harvested in
1980 was est irnated at 20.4 mill i on pounds wi th a val ue of
$18 million.The average annual herring catch is 6.4 mil-
lion pounds,worth approximately $1.3 million.The smaller
halibut fisheries yield approximately 0.6 million pounds,
worth $400,000,while the shellfish harvest of crab and
shrimp yields 16 million pounds annually,worth $8.5 million
(CIRI/Placer 1981).
Subsistence fishing is also conducted by local natives,par-
ticularly by those from the Tyonek area.Species harvested
include clams,bottomfish,salmon,and smelt.
The diverse wetland and aquatic habitats support large num-
bers of birds,particularly during the migration periods.
E-I0-118
4.1 -Coal-Fired Generation Alternative
The coastal wetlands and mud flats are heavily utilized by
waterfowl,cranes,and shorebirds,while the offshore waters
and sea cl i ffs are i nhabi ted by sea bi rds such as gull s,
puffins,and murres.
Marine mammals present in the Cook Inlet area include seals,
whales,and dolphins.Only the harbor seal and Beluga whale
are known to occur in the upper Cook Inlet.
(g)Cultural Resources
Historic sites occur within the modern town of Tyonek.
Other sites nearby include Californsky's fish camp,old vil-
lage sites,and cemeteries.Few archaeological sites are
bel ieved to be in the area,primarily because the violent
actions of the tide would have destroyed most of the sites
left,by coastal-dwelling natives.
(h)Socioeconomic Conditions
The only substantial settlement on the west coast!of Cook
Inlet is Tyonek,inhabited by approximately 270 Tanaina
Indians.The village is typical of many small villages in
Al aska,with hi gh unemployment.Recently,government pro-
grams have somewhat alleviated this problem.
Employment on the west side of Cook Inlet is supplied by
three commercial developments:the Chugach generating
station,Kodiak 1 umber mill,and crude oil processing and
transportation facilities.Commercial fishing and subsis-
tence activities are the major sources of income.
Housing consists primarily of prefabricated structures.One
school,with total enrollment of 140,serves kindergarten
through the 12th grade.Police protection is provided by
the Alaska State Troopers utilizing a resident constable.
Fi re protection is provi ded by the U.S.Bureau of Land
Management.Medical services are available in a medical
center located in the village.Water is supplied from a
nearby 1ake and wastewater di sposed of vi a sept ic systems
(CIRI/Placer 1981;CED 1980).
Transportation facilities in the areas are limited to gravel
logging roads and small airstrips.
(i)Land Use
Land ownership in the project area is varied and includes
,the state of Al aska,Cook Inlet Region,Inc.,Tyonek Native
Corporation,and the Kenai Penninsula Borough.Land owned
E-10-119
4.1 -Coal-Fired Generation Alternative
by the state includes resource management lands,industrial
land,reserved used lands,and material lands.Most of the
state land in the Beluga coal district is resource manage-
ment land;one of the designated users of this land in coal
prospecting and leasing and mining permits.The Trading Bay
State Game Refuge is within a separate category and managed
by the Al aska Department of Fi sh and Game.
4.1.2 -Envi ronmenta 1 Impacts
(a)Ai r Qual ity
Coal mining and power generation w"ill result in emissions to
the atmosphere of particulate matter,nitrogen oxide,sulfur
oxide,carbon monoxide,and hydrocarbons,as well as lesser
amounts of other poll utants.The i r impacts cannot be quan-
tified without detailed air monitoring and modeling;
however,some generalizations can be made.
Mining emissions would comprise primarily particulate matter
from vehicular traffic,surface disturbance,and wind across
coal pi 1 es and di sturbed areas.Heavy equi pment operat ions
would also result in nitrogen oxide,carbon monoxide,hydro-
carbon,and sulfur oxide emissions.
Beluga coal is characterized as sub-bituminous (6,500 -
7,500 Btu/lb)with low sulfer (0.2 percent),high moisture
(25 to 28 percent)and high ash content (14 to 25 percent)
(CIRI/Placer 1981).This sulfur and heat content is compar-
able to that of Powder River Basin coal in Wyoming,but the
moisture content is approximately twice the Powder River
value.Utilizing these figures and calculations from pre-
vious reports yields approximate daily emission rates for a
700-MW facility (USFWS 1978).
S02
Fly ash
40 to 60 tons per day (no scrubber)
3 to 5 tons per day (with precipitators)
Exact amounts of these pollutants and of nitrogen oxides
cannot be calculated without specific design criteria and
details on pollution-(~ontrol devices.Because no data were
available for a 400-MW facility as discussed earlier,the
above figures are presented.Emissions from a 400-MW
facility would be less.
A Prevention of Significant Deterioration (PSD)review would
be necessary prior to construct ion.Thi s process would
requi re that any emi ss ions be withi n the all owabl e i ncre-
ments established in the Clear Air Act regulations.How-
ever,because the area is currently relatively free of air
E-10-120
..-
I
i
"""'"!
4.1 -Coal-Fired Generation Alternative
pollution~the emissions from coal mlnlng and generating
station operation would likely result in a noticeable degra-
dation of existing air quality.In addition~short term
maximum concentrations could~under certain meteorological
conditions~exceed the National Ambient Air Quality stan-
dards near the power plant (Battelle 1978).This would
would be particularly true during periods of inversion.
(b)Topography~Geology~and Soils
Coal mining and construction of the generating facil Hies
have the potential to impact topography and soi 1sin the
area.Mi ning operations woul d unavoidably change the topo-
graphy of the area~although reclamation and compliance with
regulations of the Surface Mining Control and Reclamation
Act would minimize these impacts.Soil erosion from mining
and plant construction activities could also occur if proper
precautions are not implemented.
r
-
(c)Hydrology
Little is known about ground water resources in the area
(CIRI/Placer 1981).Strip mining has the potential to
degrade the water qual ity and interferes with ground water
flows.Regulations of the Surface Mining Control and Recla-
mation Act and the state of Alaska would require these
impacts be minimized.
Surface water could be affected from runoff.from the mined
area~coal storage pi1es~site grading~road building~and
other construction activities.Plant operation would also
result in poll uted and heated water from electrical genera-
tion.Potential sources of contamination are acid mine
drainage~treatment chemica1s~dust,spoil-pile runoff~fuel
spillage~ash~and industrial waste.This could impact
surface water quality through changes in turbidity~rates of
photosynthesis~dissolved oxygen~temperature~pH~and heavy
metal s.
It can be expected all point sources of discharge will meet
Federal New Source Performance standards and other regul a-
tions of the Federal Water Pollution Control Act.However~
because of the high water quality of the river and streams
in the area~any impacts will be noticeable.In addition~
because of the seasonal f1 uctuat i on of flows in the a rea ~
the impacts of sedimentation and other water quality effects
may be increased (Battelle 1978).
E-I0-121
4.1 -Coal-Fired Generation Alternative
(d)Terrestrial Ecosystems
Surface mining will unavoidably result in the removal of
vegetation and wi 1 dl i fe habitat.If not properly restored
and revegetated,erosion would result and the habitat per-
manently reduced in val ue.The areas of the generating
facility,roads,and ancillary facilities would be pennan-
ently removed as wildlife habitat.
In addit i on to the di rect impacts to wil dl ife,secondary
effects would also occur,such as increased hunting pressure
on moose and bear because of a larger human population and
greater act i vity.New roads will add access to the a rea,
resulting in habitat disruption and disturbance to the ani-
mals.Human/wildlife conflicts are more likely to occur and
result in increased mortality of bears and nuisance species.
Thi s reduct ion in habi tat and other secondary effects wi 11
result in a substanti al loss in carrying capacity for most
wildlife species and a subsequent decline in their
population levels.
(e)Aquatic and Marine Ecosystems
The impacts to aquatic and mari ne ecosystems woul d depend
primarily upon the effectiveness of siltation control
devices and degree of water treatment.Some aquatic habitat
would be lost because of mining activities.In addition,
increase sedimentation,interuption or reduction in flows,
and degradation of water quality could all result in nega-
tive impacts to aquatic habitats,thereby reducing fish
population in the area.The potential also exists for
changes in water quality to interfere with anadromous fish
runs and reproduction,thereby affecting marine resources in
Cook Inlet.Impacts to other marine resources,unless water
quality is severely impaired,are not expected to occur.
As an example of the magnitude of impacts that could occur,
the Alaska Department of Fish and Game has estimated that if
half the anadromous fish production were lost from the
Chuitna River system,the annual loss of fish available to
Cook Inlet fisheries would be within the following ranges:
Pink salmon 70,000 -650,000
Coho salmon 5,250 -48,750
King salmon 2.100 -19,500
Chum sal mon 700 -6.500
Total salmon 78,050 -724,750
E-10-122
-
4.1 -Coal-Fired Generation Alternative
(f)Cultural Resources
Potential impacts to cultural resources include disturbance
of sites,destruction of artifacts,and increased access to
the areas resulting in disturbances to sites previously in-
accessible.A cultural resource survey would be required on
all areas to be mined or built upon.If significant sites
are discovered,mitigation will likely 'occur,utilizing
either avoidance or salvage operations.
Thus,wit~the exception of the disturbance of areas outside
the project site but not currently accessible,impacts to
cultural resources should be mitigatable.
(g)Socioeconomic Conditions
There are many impacts which affect socioeconomic factors in
an area.These include construction camp location (if any),
commuter modes,family relocation,worker need for services,
amount of 10ca1 labor available,and construction schedules.
Thus,only generalized impacts can be predicted.
Depending upon the size of the generation facility,direct
and i ndi rect jobs will range from 400 to 1300 (CEO 1980;
CIRl/Placer 1981).Most of these workers would likely come
from the avai 1ab 1e work force in Anchorage,with some from
the Kenai Peninsula and the local village of Tyonek.
If a construction camp or new village were created near the
plant site,local population would increase by several thou-
sand.This would require construction of new roads,sewage
and water systems,and other infrastructures necessary to
support,these workers.and thei r fami 1i es.Some of these
services would be supp1ied by the Kenai Peninsula Borough,
but most would likely be supp1ied either by the state of
A1aska or the company building and operating the generating
facility.Thus,financial impacts to the borough should be
small (CIRIjPl acer 1981).However,because the Bel uga coal
fields are only 75 miles (120 km)from Anchorage,it is
unlikely that a large,permanent village would be required,
since most workers would prefer to live in the construction
camp and leave their families in the Anchorage area.
The generating facility could add substantially to tax
revenues in the Kenai-Soldotna area.This revenue would
likely expand government services in the area and thereby
create additional employment opportunities.
E-1O-123
4.2 -Tidal Power Alternatives
Fi nally,there woul d 1 ike ly be impacts to the vi 11 age of
Tyonek.The large generation facility would result in
increased contact with non-Native people and their way of
life.There could also be conflicts with subsistence
hunting and fishing activities and a potential,through
sport hunt i ng,to reduce the resource bases uti 1i zed by the
Natives.These increased contacts with non-Natives could
result in the continued erosion of Native customs and
cultural values.
Employment opportunities would be available for Tyonek
village residents.In addition,Native business could
likely increase to supply goods or services to the construc-
tion workers and construction site.Thus,the project would
result in positive economic benefits to the village.
In summary,soci oeconomi c impacts to the a rea of pl ant
development would not be great,primarily because of the
proximity of the site to the greater Anchorage area.This
area would supply most of the labor force and absorb most of
the impacts from development of goods and services to supply
the site.Population levels at the site would increase,
with the magnitude dependent on the nature of the
construction camp;however,it is likely there would not be
more relocation of families to the site.Positive economic
benefits would occur to the Native village of Tyonek,but
potential negative impacts to the cultural values also
exist.
(h)Land Use
Mining operations in this area would be consistent with
intended land use plans.The leasing program implemented by
the state encourages energy development.A portion of the
area now is owned by CIRI Native Corporation,also which
encourages energy development.
4.2 -Tidal Power Alternatives
The Cook Inl et area has long been recogni zed as havi ng some of the
highest tidal ranges in the world,with mean tide ranges of more than
30 feet (9 m)at Sunrise on Turnagain Arm,26 feet (8 m)at Anchorage,
and decreasi ng towards the lower reaches of Cook Inl et to 15 feet
(4.5 m)or so near Seldovia.Information concerning feasibility of
tidal power generation and environmental impacts was gathered mainly
from current studies being conducted for the Office of the Governor,
State of Alaska.Initial studies of Cook Inlet tidal power development
(Acres 1981a)have concluded that generation from tide fluctuation is
technically feasible,and numerous conceptual schemes ranging in
estimated capacity of 50 MW to 25,900 MW have been developed.
E-1O-124
4.2 -Tidal Power Alternatives
4.2.1 -Preferred Tidal Schemes
Studies conducted for the Governor l s office (Nebesky 1980)have
indicated three sites are best suited for tidal power develop-
ment.This analysis,based on capacity,energy generation and
costs,considered sixteen sites and chose the following (Figure
E.10.12):
(a)Rainbow
This site crossed Turnagain Arm from a point near the mouth
of Rainbow Creek to a point approximately two miles east of
Resurrection Creek.
(b)Poi nt MacKenzi e/Poi nt Woronzof
This site crosses Knik Arm near Anchorage.
_.
(c)Eagle Bay/Goose Bay
This site crosses Knik Arm at the narrowing of the channel
along Eagle and Goose bays.
Tidal power generation basically involves impounding water at
high tide level and converting the head difference between the
corresponding basin and the ebbing tide.Present technology
allows for extraction of this energy by low-head hydraulic tur-
bines to generate electricity.A tidal power generation project,
therefore,would involve construction of dams,sluiceways,power-
houses,and transmission lines (Acres 1981a).
4.2.2 -Environmental Considerations
Environmental assessments of the preferred Cook Inlet tidal
develoj:Xllent involve consideration of physical and biological
characteristics,anticipated impacts,and short-and long-term
effects.
(a)Physical Characteri stics
Several major chardcteristics of Cook Inlet are relevant to
an understanding of the processes and the potential for
change in the estuarine environment.These are the tidal
regime,hydrology,sediment load,and climate.
The mean tide range in Knik and Turnagain Arms is 25 to 30
feet (7 to 9 m).This extreme tidal variation,combined
with shallow water depths,results in a high velocity cur-
rent,turbulence,and high levels of suspended sediments.
E-10-125
4.2 -Tidal Power Alternatives
Thus,suspended sediment load is al so affected by the hi gh
concentration of silts and sediments present in glacial
runoff that enters Cook Inlet.
Runoff from glaciers also affects the salinity concentration
in Cook Inlet.In the summer months,when freshwater flows
are high,salt concentrations drop and suspended load
increases.In the winter,as streamflows diminish,salinity
concentration increases.
(b)Biological Characteristics
Cook Inlet is an estuary where freshwater and saltwater
environments meet.These areas are usually highly produc-
tive partly because of high nutrient levels.
In Knik and Turnagain Arms,high turbidity and limited light
penetration result in low biological productivity.Resident
and shell-fishery populations are present only in low num-
bers;however,anadromous fish do use the turbid water for
passage between the lower inlet and the natural streams.
Five species of salmon are found in the tributaries to the
Knik and Turnagain Arms.Comparatively,the Knik Arm
tributaries appear to sustain a more significant anadromous
fishery than Turnagai n Arm.The important salmon rivers in
Turnagain Arm are Chickaloon River,Bird Creek,Indian
Creek,Portage Creek,Resurrection Creek,and Six Mile
Creek.Of these,the largest salmon runs have been
identified in the Chickaloon River.In Knik Arm,the most
important salmon tributary is the Little Susitna River.
Other important streams are Fish Creek,Wasilla Creek,
Cottonwood Creek,Knik River,and Matanuska River.
Intertidal areas,mud flats,and lowlands are extensive in
the Cook Inlet area partially because of the wide tidal
fl uctuations.Mud flats are broad expanses with 1 ittle
vegetation.Above these areas are marshl and habitats,sup-
porting grasses,emergents,submergents,and shrub vegeta-
tion.In terms of biological productivity,these coastal
marshes are the most important areas within Cook Inlet.
They provide important nesting and staging habitat for hun-
dreds of thousands of shorebi rds and waterfowl duri ng the
spring and fall migrations.This results in extensive
recreational hunting opportunities for Alaska's most heavily
populated area.During the years from 1971 to 1976,approx-
imately 30 percent of the state duck ha rvest occurred in
Cook In 1et.
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4.2 -Tidal Power Alternatives
Fi ve coastal marshes in Cook Inl et are protected as state
game refuges;four of these are in proximity to proposed
tidal power development sites.They are Potter Point,
located just south of Anchorage at the mouth of Turnagai n
Arm;Pal mer Hayfl ats,in the upper reaches of Kni k Arm;
Goose Bay,on Knik Arm ten miles north of Anchorage;and
Susitna Fl ats,to the west of Poi nt MacKenzi e at the mouth
of the Susitna and Little Susitna rivers.Other important
marshlands not protected as refuges are Eagl e River Fl ats,
across Knik Arm from Goose Bay,and Chickaloon Flats,across
Turnagain Arm from Potter Point.
Al though Cook Inl et is not an important habitat area for
marine mammals,a few species do occasionally migrate to the
area.-Bel uga whal es are known to occur in the water off-
shore from Anchorage.
The endangered Arctic peregrine falcon is known to nest in
the upper Cook Inlet region and to utilize coastal areas
during the migration periods.Bald eagles,not classified
as endangered in Alaska,also are present in the region.No
endangered waterfowl speci es have been verifi ed in Cook
Inlet,although habitat for the Aleutian Canadian goose may
occur in the southern reaches of the Inlet.
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(c)Anticipated Impacts
The construction and operation of a tidal power plant in
either Knik or Turnagain Arm will affect the physical pro-
cesses of Cook Inlet and cause changes that may directly or
'indirectly influence the natural environment.These impacts
can be divided into short-term and long-term effects.
(i)Short-Term Effects
Short-tenn effects are those associated with con-
struction activities and include:
-Site development and construction;
-Site access and traffic;
-Operation of equipment;
-Dredging and dredged materi~l disposal;and
-Development of construction material sources.
These short-term activities will affect,for the most
part,only the environment in the vicinity of the
site and will extend for the construction period.
Some permanent changes will occur in the environment,
such as placement of permanent facilities,but the
effects will be site-specific.It should be noted
4.2 -Tidal Power Alternatives
that many of the negative impacts normally associated
with construction can be el iminated by proper waste-
water facilities,erosion control methods,and other
mitigating measures.
-Dredge and Fill
The activities associated with dredging and filling
may cause the most significant construction effect,
because of the quantities of materials being moved
and the necessary use of remote sites for dredged
material disposal and acquisition of construction
mat e ri a1s •
The Eagle Bay and Rainbow sites will both require
dredgi ng of 30 mcy (23 mcm)of sediments from the
inlet bottom.Most of this will not be suitable as
construction material and will need to be trans-
ported from the site for di sposal •Acceptabl e
sites for marine dumping can be found downstream
where the Inlet broadens,but care must be taken to
avoid commercial fisheries located in the Fire
Island vicinity.The dredged material itself is
not polluted or chemically contaminated.The phy-
sical constituents of the dredged material are
likely to be similar to the bottom sediments found
further downstream.Di sposal of dredged materi al
may temporarily disturb bottom organisms,but habi-
tats would soon be re-establ ished.Careful plann-
ing in the timing and choice of disposal sites can
insure minimal impacts.
Because little of the dredged material at either
the Eagle Bay or Rainbow sites would be suitable as
construction material,upwards of seven mill ion
cubic yards of fill material must be procured from
offsite sources.This would cause disturbance of
upland habitats resulting fran the activities of
excavation and transport.Unavoidable impact of
these activities may be reduced by avoiding devel-
opment in sensitive environments.
The Point MacKenzie site is most attractive from
the standpoint of dredge/fill operations.Less
than one quarter of the dredging required for
either Rainbow or Eagle Bay will be necessary for
Point MacKenzie.Additionally,a substantial por-
tion of the material removed will be rock,gravel,
E-10-128
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4.2 -Tidal Power Alternatives
and sand that may be appropriate for dam construc-
tion.This further diminishes the volumes required
for acquisition and disposal.
-Site Access and Traffic
Establishing access to the site by land and by sea
and providing for the high volume of traffic that
will occur during the construction period will
affect the environment.Roads and marine docking
facilities will be constructed.Marine traffic for
construction purposes,delivery of equipment,and
dredging operations will occur in areas where
little or no shipping or boating of any type has
occurred.Access roads will be establ ished in
previously undeveloped areas.
To minimize these impacts,land routes can be
chosen to avoid sensitive areas such as waterfowl
habitat,and the high volumes of traffic can be
limited to construction periods.Marine traffic is
not likely to affect the few resident species nor
block the mobil e anadrorilOus speci es as they mi grate
up and downstream.The marshlands,waterfowl habi-
tats,and upland game reserves would be most
affected by development,noise,and traffic activi-
ties.
-Site Development and Construction
The preparation of the site for construction,as
well as the activities associated with construc-
ti on,will have its greatest impacts on the site
itself.Alterati ons of topog raphy and exi sti ng
habitats will occur.The presence of large,noise-
producing equipment and human activity will be dis-
ruptive to habitats.
Site development can be conducted in a manner that
will minimize impacts.Minimization of land use,
implementation of plans for erosion control and
1andscapi I1g,and development of permanently useful
facilities such as dry docks will aid in reducing
impacts.
Noi se factors are potenti ally most si gnifi cant at
the Eagle Bay site,which is located only a few
mil es upstream from Goose Bay State Game Refuge.
The noi se 1 evel s have the potenti al to di srlJpt
waterfowl,but habituation can be expected.
4.2 -Tidal Power Alternatives
The marine construction activities will affect the
aquatic environment.Dredging,fill placement,dry
dock construction,caisson construction,and
installation will occur in the water.There are
few resident species to be disturbed,but migration
of anadromous fish may be affected.It is likely
that measures to insure fish passage will be
required during all stages of construction,reduc-
ing these impacts.
(i i)Long-Term Effects
Certain aspects of pl ant operation may alter the
physical regime of the estuary.These will be dis-
cussed in terms of their environmental implications:
-The altered tidal regime and estuarine hydrology;
and
-The alteration of hydraulic characteristics:cur-
rents/velocities,erosion/sedimentation.
Additionally,the following long-term impacts will be
cons i dered:
-Impacts added by the causeway alternative.
-Effects of an Altered Tidal Regime
The process of capturing the tide in a basin behind
the barrier and regulating the flows through it has
two important consequences.First,the mean tide
level in the newly formed basin will be raised by
several feet.Second,the mean tide range will be
substantially decreased.Mean high tide levels
will probably be slightly lower and mean low tide
levels will be higher than what presently exist.
The result of these changes can be conceptual ized
as follows.The extent of the mud flats will
likely be somewhat diminished.The lowest reaches
of the mud fl ats will remain totally submerged,
since the tide,will never reach its previous low
levels.At the upper limits of the mud flats,
marshl and vegetati on may encroach seaward.As the
frequency of inundations decreases at the edges of
the marshland,marsh grasses will grow on the
former edges of the mud flats.This will result in
shifts in locating mud flats and possible changes
in acreages.
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4.2 -Tidal Power Alternatives
Other changes may alter the distribution of plant
types on the lands affected by the tid,es.A net
increase in the mean water level may alter the
water table and hence runoff and other hydrologic
characteristics of adjacent marshlands.Also
significant is the effect of altered salinities
that may occur as tidal waters are stored in the
basin.There is some potential that intrusion of
saltwater may have harmful effects on the ground
water tabl e.It shoul d be noted that the Cook
Inlet marshlands are high stress environments,
characterized by large seasonal variation of
salines.Therefore,changes in seasonal variation
of sal inities will probably not be detrimental to
marshland vegetation.
Other hydrologic characteristics could be affected,
such as backwater and flooding.The raised water
table could affect lowland drainage and vegetation.
It appears that,although the potential for altera-
tion is great,it is also possible that only slight
changes in popul at ions will occur t hat wi 11 not
greatly alter the nature of the envi ronment as a
habi tat for waterfowl,shorebi rds,and furbeari ng
species.
The tidal regime may also be altered downstream
from the barri ere However,the impoundment of a
portion of high tide water behind the barrier will
not greatly alter existing water 1 evel s or tidal
fluctuation downstream.Possible effects caused by
resonance of tidal waves will have to be studied in
detail,but it appears 1 ikely that the effects of
the barri er wi 11 have much greater potential for
impact upstream from the dam.
-Hydraulic Characteristics of the Basin
Regulation of flow in the basin will affect hydrau-
1 ics local to the dam itsel f,as well as havi ng
more widespread impacts.Existing current patterns
and velocities throughout the basin would be
al teredo The most noti ceabl e change wi 11 occur
near the dam where the concentration of flow veloc-
ities through turbines and sluiceways would alter
local flow patterns.These local high velocities
will be dissipated with increasing distance from
the dam.The decreased tidal range may result in
an overall decrease in turbulence and mixing,
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4.2 -Tidal Power Alternatives
although the tidal range will still be substantial
in relation to the depth of water so that the
regime of total mixing may not be altered.
The effect of siltation on the environment and on
the operation of the tidal power plant has not been
fully assessed.Investigations of sedimentation in
the Bay of Fundy,La Rance,and other construct i on
reported that siltation caused by construction
within the tidal flow is a function of the degree
of flow reduction caused by construction;the
availability of appropriate sized sediment in the
water;and the combined supply of material to the
site.Knowledge of the origin of sediments and the
existing transport mechanism is necessary to the
analys is of the 1 atter.
Sedimentation and erosion processes may be affected
in the silt-laden estuary.The mud flats and
bottom conditions of the Arms are highly mobile.
Changes can result from a net increase or a net
decrease in velocities and from redistribution of
wave energy on the shoreline.These will have the
greatest·potential for harmful impacts to the
natural environment on the shorelines of marsh-
lands,where erosion of the outlying mud flats
could result in eventual erosion of the marshland
and loss of habitat.It is possible,however,that
a net decrease in energy in the basin (lower tide
range,decreased mixing,decreased tide range)will
result in higher sedimentation rates.If this is
the case,it may cause decreased storage in the
basin,and correspondingly,a buildup of mud flats
and an extension of marshlands.
The effects of sedimentation may also be signifi-
cant downstream from a barrier in Cook Inlet~
Observation of recently constructed causeways at
Windsor,Nova Scotia,and on the Petitcodiac
estuary in New Brunswick reveals the development of
1a rge,mi d-channel mud fl ats seawa rds of the
barrier caused by local flow reductions.This
could result in a reduction of sediments which are
normally deposited further downstream in the
estuary.Effects on navigation may be significant
in the Knik Arm where shoaling is al ready a problem
in the approaches to Anchorage harbor.
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4.2 -Tidal Power Alternatives
Another factor related to sediment load in the
Inlet waters is that of penetration of light as
required for biological productivity.At present,
high turbidities limit light penetration.This may
be the 1 imit ing factor for growth of the aquatic
food chains.It is possible that along with a
decrease in sediment load,an increase in food
production could result in a habitat more amenable
to aquatic species.
-Causeway Development
The addition of a causeway to the tidal power pro-
ject would not create any additional impacts to the
upstream and shoreline environment.The most sig-
nificant impacts would result from development of a
permanent road through previously undeveloped areas
and from the residential and commercial growth that
woul d occur because of the new access.Other
impacts to the Inlet include increased traffic
noi se across the causeway and increased human
access to the wetlands for recreational purposes.
4.2.3 -Effects on Biological Resources
Construction and operation of a tidal power facility has the
potential to affect anadromous fish in Cook Inlet.Because of
the commercial and recreational importance of this resource,
specific mitigation techniques would have to be developed to
minimize these impacts.
Anadromous fish return to their natural streams to spawn.The
mechanism by which they locate these streams is not fully under-
stood,but it is believed the fish respond to changes in water
chemistry.Thus,although it is unlikely retiming of tides will
affect the hydrology and physical or chemical composition of
water upstream from the reach of tidal fluctuations,the changes
in sediment load and salinity of water below the power facilities
could potentially affect the migration.
The largest salmon runs in Turnagain Arm occur in the Chickaloon
River.Since the river is located approximately 10 miles (16 km)
downstream from the Rainbow site,migration should not be direct-
ly affected.In the Knik Arm area,the most important salmon
tributary is the Little Susitna River,which is 10 miles down-
stream from the Point MacKenzie site;impacts there al so should
not be great.However,in both cases it should be noted that as
fish appproach their natal streams,they may wander as far as 10
miles (16 km)past the mouth before turning back to the ultimate
goal.In this manner,the Point MaCKenzie and Rainbow sites
E-I0-133
4.2 -Tidal Power Alternatives
could conceivably affect migration to the Little Susitna and
Chickaloon River,respectively,although the damsites appear to
be the limits of the interaction zone.
(a)Wetlands and Waterfowl Habitat
There are three primary mechanisms by which the tidal plant
would directly cause impacts to marshlands.They are:
-Disturbance along the shores of the impounded basin;
-Interaction with the construction site,noise,activity,
and equipment;and
-Imposition of an altered flow regime downstream from .the
dam.
Of these three primary impacts,potentially the most signi-
ficant would be the effects of the altered tidal regime on
the stabil ity and productivity of the marshl and ecosystems
with in the impoundment bas in.Altered sedimentation pat-
terns coul d resul tin eroded shorel i nes.A rai sed water
tabl e coul d resul tin a more sal i ne ground water tabl e.
Altered surface hydrology may affect filtering and transport
of nutrients and organics within the marsh.A loss of marsh
area and a loss of vegetation types required for support of
bird populations can be envisioned,thus diminishing produc-
tivity and resulting in degradation of the waterfowl habi-
tat.
Alternatively,sedimentation may result in an enlargement of
marshlands.Effects of changes in hydrology,inundations,
and nutrient supplies could produce an environment more
attract i ve to waterfowl and other speci es.Somewhere bet-
ween the best case and the worst case 1ie any numbe r of
variations where,for example,vegetation or land areas may
be altered but have little impact on bird populations.The
conclusion,at this point,is that the interactions between
hydrology,hydraulics,and the wetland ecosystem must be
better understood in order to predict effects with more
reliability.This should be the'ain focus of future
envi ronmental studies.
Operation of the tidal project may affect the hydraulics of
the inlet downstream from the dam.These effects should be
studied in greater detail for their impacts on coastal
marshlands.Later phases of engineering studies should in-
clude modeling the effects of the dam on downstream hydrau-
lics and water levels to determine ecological impacts.
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4.2 -Tidal Power Alternatives
(b)Marine Mammals
Construction of tidal-generating facilities could affect the
movement of marine mammals in the area.Care must be taken
in design of intake structures and dam approaches to prevent
harm to these animals in the event of their interaction with
the structure.Other mammals may also be involved,and
r""their movements may extend to the other damsites.Thislquestionshouldbemorethoroughlyinvestigatedinlater
studies,including potential effects on marine mammal food
sources.
4.2.4 -Other Effects
(a)Water Quality
Present water qual ity is characteri zed by extremely hi gh
turbidity,relatively high dissolved oxygen content,vari-
able salinity and nutrient concentrations,and low levels of
primary biological productivity.Several activities associ-
ated with the tidal project may affect water quality;these
incl ude the excavation and construction of the darn,
increased ship traffic,and operation of marine equipment,
as well as the regulation of flows to and from the basin.
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Dredging,excavat i on ,and placement of materials for dam
construction in the submarine and intertidal envi ronments
may temporarily increase suspended sediment concentrations
near the dam.Given the existing turbulence and turbidity
of the water,this should not be a problem~Additionally,
the introduction of new materials (sand,rock,gravel)from
other sources may result in leaching of some chemical con-
stituents not normally found in the waters.The possibility
of serious chemical problems is very small.
The presence of construction equipment,tugs,barges and
human activity indicates an increased possibility for such
accidents as oil spills,fires,dumping of debris,and dis-
posal of untreated sewage into the water.Adherence to
heal th and safety pl ans and control of construction areas
can minimize most undesirable effects.
The presence of the dam and the resultant flow patterns may
act as a physical barrier which 1 imits exchange of salt,
nutri ents,sediments,etc.,between the freshwater i nfl ows
and the saltwater influence from the ocean.Although the
total flow of water may be reduced by the dam,large volumes
of water will still be exchanged.A well-mixed basin would
result,although local flow patterns and water quality may
be affected.
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4.2 -Tidal Power Alternatives
It appears that~though there are many potentials for impact
to water quality~the associated risks are low.
(b)Climatology
Short-term and long-term changes in the climate of the re-
gion may occur as a result of tidal power development.
Changes in ice formation~for example~could alter air tem-
peratures in the basin vicinity.
(c)Rare and Endangered Species
It is not anticipated that tidal power development would
affect the endangered peregrine falcon.
4.2.5 -Socioeconomic Assessment
The socioeconomic issues of a tidal development would be similar
to those of other capital intensive developments~particularly to
those of a large hydropower project.The construction period,
characterized by very high levels of activity and expenditure~
would be followed by a long operational period during which these
levels would become quite low.Annual costs of operation consist
mainly of capital charges.The costs of maintenance and replace-
ment would be quite small compared to these capital charges,and
the other costs of operating the facility would be negligible.
A tidal project presents,however~certain aspects and options
that are very different from more conventional power modes and
which may yield distinctly different social and economic results.
The following examples will illustrate the characteristics in the
tidal power development that may make it unique from the socio-
economic viewpoint:
-Storage and generation will take place in the sea.Conse-
quently~very few~if any~relocations of people and very
1ittl e reall ocation of land and water resources will be
required.
-One of the more likely construction options will be the float-
ing in of hugh prefabricated caissons and sinking them on
location as components of the structure.If this method is
adopted,a significant amount of the work may be done off the
site.
-Depending upon final design and the site selected for develop-
ment,a tidal project in the Cook Inlet will require from 30 to
60 turbine-generating units.Such a large number may be suffi-
cient to justify establishment of a local industry for their
manufacture and overhaul.
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4.2 -Tidal Power Alternatives
Tidal power will be generated in surges lasting from 4 to 6
hours followed by interruptions of approximately 8-1/2 to 6-1/2
hours durati on (adding up to 1unar cycl e of 12 hours and 25
minutes).Energy-intensive industries that could work on the
rhythm of power availability might find the general region of
tidal power plants to be an attractive location.
4.2.6 -Impact on Adjacent Land Uses
The major impacts from tidal development in the Cook Inlet would
occur in the Greater Anchorage Area Borough,located in the
south-central porti on of Al aska at the head of Cook Inl et on a
roughly triangular area of land between the two estuarine drain-
ages,Knik and Turnagain Arms.
The areas within the boundaries of the municipality of Anchorage
suitable for urban development are to the west of Chugach State
Park,south and east i ncl udi ng Alyeska-Gi rdwood,and north and
east to Eagl e Ri ver-Bi rchwood.Potential changes inland use
woul d be to convert these areas into i ndustri al use,si nce busi-
nesses are attracted by availability of power.Aesthetic impacts
would not be great,assuming industrial development occurred on
land designated for this purpose.
4.2.7 -Materials Origin Supply Study
The raw materi al s,·i ntermedi ate goods,and equi p1lent requi red for
a tidal project can be grouped into three main categories:
(a)Raw Materials
These materials include aggregate,rock,cement,and lumber.
It is expected that agg regate a nd rock can be suppl i ed
locally.The final aggregate (sand)will be transported
from the Palmer area.The coarse aggregate for concrete
will be crushed in the rock quarry areas near thesel ected
sites as follows:
Rainbow:North and south side of Turnagain
Arm--5-mil e (8 km)haul
Point MacKenzie:North side of Turnagain area near Rainbow
site--30-mile (50 km)haul
An estimate of direct labor required for the production of
these items indicates that about 300 to 400 jobs may be
involved during the construction period.
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Eagle Bay:Mount Magnificant--15-mile (25 km)haul
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4.2 -Tidal Power Alternatives
(b)Steel Products
These include reinforcement and fabricated gates.It is
likely that these supplies would be from sources outside
Alaska.
(c)Generating Equipment
This includes hydroelectric and electrical equipment,such
as the turbines,generators,transformers,and switchgear.
This equipment would be supplied from North America or
Europe depending on market conditions.
4.2.8 -Labor Supply and Limitations
A preliminary estimate indicates that the direct,onsite,labor
requi rements for the three sites considered woul d be approxi-
mately as follows:
Site
Average man-years per year:
Over 7.5 years
10.5 years
11.5 years
Eagl e
Ra i nbow Bay
1875
2000
Po i nt
MacKenzie
2500
Peak demand man-years per
year:2000 2200 2750
The peak labor requirements for any site development are not much
higher than the average requirement,and it is likely that care-
ful scheduling of the work will make it possible to arrange for a
relatively steady level of employment throughout the construction
period.
For each of the si tes,the total demand amounts to less than 3
percent of the total labor force and about 33 percent of the
construction labor force in the impact region (Anchorage-Mat-Su
Borough)as of March 1981.It is likely,therefore,that a large
part of the labor that would be required during the 1990s could
be recruited in the surrounding region.
In 1980,the unemployment rate was about 8 percent in the
Anchorage-Mat-Su region immediately around and north of the pro-
ject sites,12 percent in the Gulf Coast region,and 10 percent
in the state of Alaska.It is possible the rate of employment
would be lower during the 1990s than at present,but it seems
unlikely it will have become very low.Most probably,sufficient
E-10-138
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4.2 -Tidal Power Alternatives
labor will be available in the region around the project sites
and construction of one of the projects would likely offer a wel-
come contribution to reduction of unemployment in the area during
the years of construction.
Supplementary labor requirements,in addition to the direct on-
site requirements,are of two types.The first consists of labor
employed in the production of supplies such as cement,concrete,
1 umber,aggregate,steel products,turbines,generators,and
other electrical products.Parts of these activities will not be
located in the impact region,or even in the state of Alaska.A
preliminary estimate indicated that possibly up to 300 or 400
additional jobs in the production of raw materials could be
created in the Anchorage region during the construction period if
in-state manufacturing facilities are developed.
Another type of supplementary labor requirement consists of addi-
ti onal jobs to supply the demand for servi ces by the 1abor
employed onsite and in supply activities.
4.2.9 -Community Impact
Direct,onsite employment would reach,in the peak years,about
2000 to 2750.The impact region would be the municipal ity of
Anchorage.A socioeconomic study by the Bureau of Land Manage-
ment indicates that population growth in Anchorage was responsive
to the growth in economic activities:Kenai oil,Prudhoe Lease,
and Trans-Alaska pipeline construction.The population of the
municipality of Anchorage was estimated in that study at 195,654
as of JUly 1,1979.It is 1 ikely that Anchorage could supply
labor and services of sufficient variety to accommodate a project
of this size.
The temporary construct i on activities may provi de opportunities
to strengthen the local infrastructure and provide 1ast i rig bene-
fits.Transport facilities,for example,would have to be im-
proved to facilitate construction.For site access,new roads or
upgrading of existing roads would have to be implemented except
at Eagle Point.Adjustments near the military airport would be
necessary at Point MacKenzie.A 'viaduct off the highway over
existing railroad tracks (north side)would be built at Rainbow
'as well as a road to the storage and work area along the shore,
(north side).Whenever possible,expansion of the transport
,facilities as required for construction should take into account
opportunities to create lasting beneficial effects,but at the
same time should not necessarily interfere withexi s ti ngcommuni-
ties.It will be desirable"if and when a decision is made to
build one of the projects,to initiate joint planning with muni-
cipal authorities early as possible to minimize the unavoidable
strains on the communities and to maximize the benefits that can
be obtained from the temporary increase in activity in the area.
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4.2 -Tidal Power Alternatives
4.2.10 -Impacts of a Causeway
Construction of a tidal power project at any site considered in
this study could be planned to provide a causeway.At Rainbow,a
crossing of Turnagain Arm could be built as an integrated part of
the tidal power project,and,therefore,its costs would be
reduced.Turnagain Arm Crossing between the Anchorage area and
the Kenai Peninsula has been considered in various studies over
the past 30 years.It has been recognized that a major improve-
ment such as a crossing of Turnagain Arm would have a great im-
pact on the area which it serves or through which it passes.
Tourism plays a major role in the regional economics of the
Anchorage-Kenai area.The opening up of territory heretofore
unserved by a highway becomes of major importance.
Alaska,with its scenery has likewise unlimited potential for
recreation.Good transportation makes realization of these po-
tentials possible as well as being one of the basic ingredients
of commerce and industry.The improvement of the basic network
of transportation within the Anchorage-Kenai area wil1 produce
favorable results with all of these activities.
A crossing of Turnagain Arm would bring the city of Kenai,the
center of a rapidly growing petroleum industry,to the existing
hi ghway system.The 1968 study by the Al aska Department of Hi gh-
ways indicated that the distance between the city of Kenai and
Anchorage through the crossing would be 94 miles (150 km)by and
Anchorage through the crossing would be 94 miles (150 km)by way
of a low level highway,whereas the distance over existing roads
is 154 mil es (247 km)over mountain roads wi th long grades and
passes subject to heavy snowfall.
The construction of a tidal power project at either Point
MacKenzie or Eagle Bay could also be planned jointly with a Knik
Arm crossing.A causeway crossing joining the two sides of Knik
Arm near Anchorage would provide civil benefits as well as de-
fense benefits.The 1972 study by the state of Al aska Department
of Highways indicated that the crossing will allow future eco-
nomic development of the west side of Knik Arm,which would cer-
tainly add to the potential ,of the metropolitan area of Anchorage
(State of Alaska 1972).It would shorten the Anchorage-Fairbanks
hi ghway and al so woul d provi de the necessary access for a new
international airport on the west side of the arm.Such a facil-
ity presents an interesting stimulus for the future economic de-
velopment of the west side of Knik Arm.In addition,the cause-
way crossing would provide means for development access of lands
north of Knik Arm.The geographic position of Anchorage,being
presently surrounded by water,mountains,and military facili-
ties,makes the development of the lands north and west of Knik
E-I0-140
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4.3 -Thermal Alternatives Other Than Coal
Arm very desirable.A crossing of Knik Arm would give access to
the Beluga area and the Alaska Peninsula with its mineral and
recreation potentials.
4.3 -Thermal Alternatives Other Than Coal
4.3.1 -Natural Gas
Natural gas resources available or potentially available to the
RailbeH region include the North Slope (Prudhoe Bay)reserves
and the Cook Inlet reserves.Information on these reserves is
summarized in Table E.10.29.
The Prudhoe Bay Field contains the largest accumulation of oil
and gas ever discovered on the North American continent.The
in-place gas volumes in the field are estimated to be in excess
of 40 trill ion cubi c feet (Tcf).With losses considered.
recoverabl e gas reserves are estimated at 29 Tcf.Gas can be
made available for sale from the Prudhoe Bay Fi el d at a rate of
at least 2.0 billion cubic feet per day (Bcfd)and possibly
slightly more than 2.5 Bcfd.At this rate,gas del iveries can be
sustained for 25 to 35 years.depending on the sales rate and
ultimate gas recovery efficiency.
During the mid-seventies,three natural gas transport systems
were proposed to market natural gas from the No rth Slope Fi el ds
to the Lower 48.Two overland pipeline routes (Alcan and Arctic)
and a pipeline/LNG tanker (El Paso)route were considered.The
Alcan and Arctic pipeline routes traversed Alaska and Canada for
some 4000 to 5000 miles (6400 to 8000 km),termi nat i ngi n the
central U.S.for distributio~to points east and/or west.The El
Paso proposal invol ved an overl and pi pel i ne route that woul d
generally follow the Alyeska oil pipeline utility corridor for
approximately 800 miles (1280 km).A liquefaction plant would
process approximately 37 mill ion cubi c meters of gas per day.
The transfer station was proposed at Point Gravinia south of the
Valdez termination point.Eleven 165,000 cubic meter cryogenic
tankers would transport the LNG to Point Conception in California
for regasification.
The studies noted above concluded with the decision to construct
a 4800 mile (7680 km),2.4 Bcfd,Alaska-Canada Natural Gas pipe-
line project,costing between $22 and $40 billion.The pipeline
project woul d pass approximately 60 mil es (96 km)northeast of
Fairbanks.Although the project was in the active planning and
design phase for several years,it is now inactive due to finan-
cial difficulty.
4.3 -Thermal Alternatives Other Than Coal
The Cook Inlet reserves (Table E.10.25)are relatively small in
comparison to the North Slope reserves.Gas reserves are
estimated at 4.2 Tcf as compared to 29 Tcf in Prudhoe Bay.Of
the 4.2 Tcf,approximately 3.5 Tcf is available for use,and the
remaining reserves are considered shut-in at this time.The gas
production capability in the Kenai Peninsula and Cook Inlet
region far exceeds demand,since no major transportation system
exists to export markets.As a result of this situation,the two
Anchorage electric util ities have a supply of natural gas at a
very economic price.Export facil ities for Cook Inlet natural
gas include one operating and one proposed LNG scheme.The
facility in operation,the Nikiski terminal,owned and operated
by Phi 11 i ps-Ma rathon,is located on the eastern shore of Cook
Inlet.Two Liberian cryogl;!nic tankers transport LNG some 4000
miles (6400 km)to Japan.Volume produced is 185 million cubic
feet per day (MMCFD)with raw natural gas requi rements of 70
percent from a platform in Cook Inlet and 30 percent from
existing on-shore fields.
There is also some potential for a gas1ine spur to be constructed
from the Cook In1 et region some 310 mil es (496 km)north to
intersect with the proposed Alaska-Canada Natural Gas pipeline
project in order to market the Cook Inlet gas.This concept has
not been extensively studied but could prove to be a viable
alternative.
4•.3.2 -Oil
Both the North Slope and the Cook Inlet Fields have significant
quantities of oil resources as seen in Table L10.30.North
Slope reserves are estimated at 8375 million barrels.Oil
reserves in the Cook Inlet region are estimated at 198 million
barrels.As of 1979,the bulk of Alaska crude oil production
(92.1 percent)came from Prudhoe Bay,with the remainder from
Cook Inlet.Net production in 1979 was 1.4 mill ion barrels per
day.
Oil resources from the Prudhoe Bay field are transported via the
800-mile (1280 km)trans-Alaska pipeline at a rate of 1.2 million
barrel s per day.In excess of 600 ships per year del iver oil
from the port of Valdez to the west,Gulf and east coasts of the
U.S.Approximately 2 percent (or 10 mill ion barrel s)of the
Prudhoe Bay crude oil was used in Alaska refineries and along the
pipeline route to power pump stations.The North Pole Refinery,
located 14 mil es southeast of Fai rbanks,is supp1 ied from the
trans-Alaska pipeline via a spur.Refining capacity is around
25,000 barrels per day,with home heating oils,diesel and jet
fuels the primary products.
E-10-142
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4.3 -Thermal Alternatives Other Than Coal
Much of the installed generati ng capacity owned by Fai rbanks
utilities is fueled by oil.Fairbanks Municipal Utility System
has 38.2 MW and Golden Valley Electric Association has 186 MW of
oil-fired capacity.Due to the high cost of oil,these utilities
use available coal-fired capacity as much as possible with oil
used as standby and for peaking purposes.
Crude oil from offshore and onshore Kenai oil fields is refined
at Kenai primarily for use in-state.Thermal generating stations
in Anchorage rely on oil as standby fuel only.
4.3.3 -Diesel
Most diesel plants in operation today are standby units or
peaking generation equipment.Nearly all the continuous duty
units have been placed on standby service for several years due
to the high oil prices and the consequent high cost of operation.
The lack of system interconnection and the remote nature of
localized village load centers has required the installation of
many small diesel units.The installed capacity of these diesel
units is 64.9 MW and these units are solely used for load follow-
ing.The high cost of diesel fuel makes new diesel plants expen-
sive investments for all but emergency use.
4.3.4 -Environmental Considerations of Non-Coal Thermal Sources
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(a)Air Pollution
Several kinds of air pollutants are normally emitted by
fuel-burning power plants.These include particulate
matter,sul fur dioxide,nitrogen oxides,carbon monoxide,
unburned hydrocarbons,water vapor,noise and odors.
(i)Particulate Matter
Particulate matter consists of finely divided solid
material in the air.Natural types of particulate
matter are abundant and include wind-borne soil,sea
salt particles,volc~nic ash,pollen,and forest fire
ash.Man-made particul ate matter includes smoke,
metal fumes,soil-generated dust,cement dust,and
grai n dust.On the basi s of data coll ected by the
U.S.Environmental Protection Agency (EPA),total
suspended parti cul ate matter (TSP)has been deter-
mined to cause adverse human health effects and
property damage.
Fuel combustion power plants produce particulate
matter in the form of unburned carbon and non-
combustible minerals.Particulates are removed from
E-10-143
4.3 -Thermal Alternatives Other Than Coal
fuel gas by use of electrostatic precipitators or
fabric filters (baghouses).They are routinely
required,however,and collection efficiencies can be
ve ry hi gh (i n excess of 99 percent).
(ii)Sulfur Dioxide
Sulfur dioxide (S02)is a gaseous air pollutant
which is emitted during combustion of fuels that
contain sulfur.Residual oil contains sulfur in
amounts of a few tenths of a percent to a few
percent,while pipeline natural gas contains rela-
tively little sulfur.Sulfur dioxide,lHe particu-
late matter,has been identified as being harmful to
human health,and it appears to be particularly
serious when combi ned with hi gh concentrati ons of
particulate matter.It is damaging to many plant
species,including several food crops such as beans.
(iii)Nitrogen Oxides
Nitrogen oxides (N02 and NO,primari ly)are gaseous
air pollutants which form as a result of high-
temperature combustion or oxidation of fuel-bound
nitrogen.Nitrogen oxides damage plants and play an
important role in photochemical smog.
Pollution control technology for nitrogen oxides has
developed more slowly than for most other air pollu-
tants.Lack of chemical reactivity with conventional
scrubbing compounds is the main difficulty.Thus
current control strategies focus on control of NO xproduction.Principal strategies include control of
combust i on temperatures (lowe r combusti on tempera-
tures retard formation of NO x )and control of com-
bustion air supplies to minimize introduction of
excess air (containing 78 percent nitrogen).
(vi)Carbon Monoxide
Carbon monoxide (CO)emissions result from incomplete
combustion of carbon-containing compounds.Gener-
ally,high CO emissions result from suboptimal com-
bustion conditions and can be reduced by using appro-
priate firing techniques.However,CO emissions can
never be eliminated completely,using even the most
modern combustion techniques and clean fuels.CO
emissions are regulated under the Clean Air Act
because of their toxic effect on humans and animals.
E-10-144
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4.3 -Thermal Alternatives Other Than Coal
(v)Water Vapor
Pl umes of condensed water vapor wi 11 emanate from a
wet cooling tower as its exhaust is cooled below its
saturation point.The plume will persist downwind of
the tower until the water vapor is diluted to a level
below saturation.In cold or cool,moist climates
the pl urnes are particul arly long because the ambient
air can hold little added moisture.Formation of
these plumes is particularly hazardous during "fog-
ging"conditions when a high wind speed causes the
plume to travel along the ground.During freezing
conditions,such plumes may lead to ice formation on
nearby roads and structures.Plume generation,fog-
ging,and icing can be controlled or virtually elimi-
nated through the use of wet/dry or dry cool ing
towers.
--
(v i)Noi se and Odor
Noise 1 evels beyond the pl ant property 1 ine can be
controlled by equipment design or installation of
barriers.Generally noise and odors are not as great
a concern as the air poll utants contained in exhaust
gasses.
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(b)Comparison of Projected Emissions
The critical comparison of fuel combustion technologies for
their imapcts on air quality is determined by the antici-
pated rate of emissions of each of the pollutants.Emission
levels for the various technologies are presented for sulfur
dioxide in Table E.I0.31,for particulates in Table E.I0.32,
and for nitrogen oxides in Table E.I0.33.Data are taken
from EPA publications or the enforced New Source Performance
Standards.
The dev~opment of these tables is based on various assump-
tions.A 33 percent efficiency of conversion is assumed for
steam electric plants,and a 25 percent efficiency for com-
bustion turbines.For the power plant sizes provided in the
tables,emissions are directly proportional to the heat rate
input for a given technology.The following heat input
factors were assumed:for oil 20,000 Btu/l b;and for
natural gas 1000 Btu/standard cubic foot.
E-I0-145
4.3 -Thermal Alternatives Other Than Coal
(c)Regulatory Framework
In 1970,the federal Clean Air Act established the national
strategy in air pollution control.The Act established New
Source Performance Standards (NSPS)for new stationary
sources,including fuel combustion facilities.Levels of
acceptable ambient air quality (National Ambient Air Quality
Standards)were also established,and the regulations were
promulgated to maintain these standards or reduce pollution
levels where the standards were exceeded.
New source performance standards (NSPS)have been
promulgated for coal-fired steam electric power plants,and
for combustion turbines.In addition,any combustion
facility designed to burn coal or coal mixtures,or is
capable of burning any amount of coal,or if such use is
planned,is subject to the coal-fired power plant standards.
Standards of allowable emissions for each fuel combustion
technology for each major pollutant for a range of sizes for
power plants are presented in Tables E.10.31 through
E.10.33.The standards are being enforced for both newly
constructed and significantly retrofitted facilities and
represent the expected level of controlled emissions from
these power plants.
In Alaska,the Department of Environmental Conservation
enforces regulations regarding ambient air quality standards
and source performance standards.A permit to operate will
be required for all fuel-burning electric generating
equipment greater than 250-kW generating capacity.
Major changes were made to the Clean Air Act in 1977 when
the Prevention of Significant Deterioration (PSD)program
was added by Congress.The PSD program has establ ished
limits of acceptable deterioration in existing ambient air
qual ity (S03 and TSP)throughout the United States.
Pristine areas of national significance (Class I areas),
were set aside with very small increments in allowable
deterioration.The remainder of the country was allowed a
greater level of deterioration.Other regulatory factors
apply to areas where the pollution levels are above the
national standards.State and local agencies may take over
the administration of these programs through the development
of a state implementation plan acceptable to the EPA.See
Table E.10.34 for National Ambient Air Quality Standards and
allowable PSD increments.
The PSD program is currently administered by the U.S.EPA.
A PSD review will be triggered if emissions of any pollutant
are above 100 tons per year for coal-fired power plants or
E-10-146
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·.3 -Thermal Alternatives Other Than Coal
above 250 tons per year for the other power pl ants.The
review entail s a demonstration of compl iance with ambient
air quality standards,the employment of best available
control technology,a demonstration that allowable PSD
increments of pollutant concentrations (currently
promulgated for sulfur dioxide and suspended particulates)
will not be violated,and a discussion of the impact of
pollutant emissions on soils,vegetation,and visibility.
It also generally includes a full year's on-si~e monitoring
of air quality and meteorological conditions prior to the
issuance of a permit to construct.In the near future,PSD
control over other major pollutants,including NO x 'CO,
oxidants,and hydrocarbons,will be promulgated.Obtaining
a PSD permit is one of the most difficult requi rements to
meet in the construction of a major fuel-burning facility.
Alaska has two permanent Class I areas in or near the
Railbelt region:Denali National Park and the pre-1980
areas of the Tuxedni Wildlife Refuge.The new National
Parks and Wil dl ife Preserves have not been i ncuded in the
original designation,but the state may designate additional
Class I areas in the future.New major facilities located
near Class I areas cannot cause a violation of the PSD
increment near a Class I area;this requirement presents a
significant constraint to the develoJ)l1ent of nearby
facilities.
,-'
(d)
A potentially important aspect of the PSD program to devel-
opment of electric power generation in the Railbelt region
is that Denali National Park (Mt.McKinley National Park
prior to passage of the 1980 Al aska Lands Act)is Cl ass I,
and it lies close to Alaska's only operating coa.l mine and
the ~xisting coal-tired electric generating unit (25 MWe)at
Healy.Although the PSD program does not affect exi st ing
units,an expanded coal-burning facility at Healy would have
to comply with Cl ass I PSD increments for S02 and TSP.
Decisions to permit increased air pollution near Class I
areas can only be made after careful evaluation of all the
consequences of such a deci si on.Furthermore,Congress
requi red that Cl ass I a reas must be protected from impai r-
ment of visibility resulting from man-made air pollution.
The impact of visibility requirements on Class I areas are
not yet fully known.
Water Poll uti on
Potential sources of water pollution include cooling system
blowdown,demineralizer regeneration wastewater,fuel oil
releases,and miscellaneous cleaning wastes.
E-10-147
4.3 -Thermal Al ternatives Other Than Coal
(i)Cooling Water Slowdown
In general,the operation of all steam cycles require
substantial amounts of cool ing water and therefore
produce cool ing water blowdown.The quantity and
qual ity of this wastewater depend upon the type of
cooling system used and the specific characteristics
of the source.In general,total dissolved solids
(TDS),chlorine,and waste heat are the primary pol-
l utants of concern.
(ii)Demineralizer Regeneration Wastewaters
All steam cycle facilities produce demineralizer
regeneration wastewaters which have high TDS level s
and generally low pH values.
(iii)Fuel Oil Releases
Potential oil pollution impacts are associated with
oil-fired power plants and other facilities which may
use oil as an auxiliary fuel.These include fuel
storage areas and the accidental rel ease of oi 1
through spillage or tank rupture.Potentially signi-
ficant impacts which may result from oil releases are
generally mitigated through the mandatory implementa-
tion of a Spill Prevention Control and Counter-
measures (SPCC)Plan,as required under 40 CFR 110
and 40 CFR 112.This plan is intended to ensure the
complete containment of all releases and the proper
recovery or disposal of any waste oil.The plan must
also be formulated in light of the Alaska Oil and
Hazardous Substances Pol~ution Regulations.
(iv)Miscellaneous Wastewaters
All steam cycle plants have many other miscellaneous
wastewaters that are derived from floor drai nage,
system component cleaning,and domestic water use.
The quant i ty and qual ity of these wastewaters wi 11
vary considerably,but oil and grease,suspended sol-
ids,and metals are the effluents of most concern.
All of these enumerated wastewaters are strictly
managed within a specific steam cycle facility.The
management vehicle is generally termed a "water and
wastewater management pl an"and in some technologies
is developed in conjunction with a "solid waste man-
agement plan".The purpose of these studies is to
E-10-148
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4.3 -Thermal Alternatives Other Than Coal
balance environmental,engineering,and cost consi-
derations,and develop a plant design and operational
procedures operation that ensures plant reliabil ity
and envi ronmental compat i bi 1i ty,and mi nimi zes
costs.
For plants developed in the Railbelt region,relevant
regulations would include the Clean Water Act and its
associated National Pollutant Discharge Elimination
System (NPDES)permit requi rements and federal effl u-
ent limitation guidelines;Alaska State water quality
standards,which regulate all parameters of concern
in all Alaska waters depending upon the specific
water resource's designated use;the Resource Conser-
vation and Recovery Act and Alaska solid waste dis-
posal requirements;and the Toxic Substances Control
Act.
Compliance with all regulations does not eliminate
water resource impacts.Alaska water qual ity stan-
dards permit a wastewater discharge mixing zone;
water qual ity concentrations wi 11 therefore be
altered in this area.Downstream water quality will
also be altered,since receiving stream standards are
rarely identical to the existing site-specific water
quality regime of'the receiving water body.If
impacts associated with wastewater discharges such as
those to aquatic ecosystems are deemed significant,
fu rther waste management and treatment technologies
may be employed.Water qual ity impacts can only be
avoided if the plant is designed to operate in a
"zero discharge"mode.This is technically possible
for all steam cycle facilities,but can be extremely
costly.
Water quality statistics for selected rivers in the
Railbelt region are given in Table E.10.35.Based on
these values,there does not appear to be any extra-
ordi nary or unusual wate r qual ity characteristi c
which woul d preclude construction or operation of a
properly designed steam cycl e facil ity.Most of the
river systems can be considered moderately mine-
ralized based upon the total dissolved solids values
and the concentrations of the major ionic components.
Values for calcium,magnesium,and silica are not low
and will 1 imit the natural reuse (without treatment)
of a number of wastewater streams,most significantly
cooling tower blowdown."Standardized"power plant
wate r management technol ogi es wi 11 be requi red to
E-10-149
4.3 -Thermal Alternat ives Other Than Coal
mitigate any adverse water qual ity impacts.Al so,
based on the sufficiently high bicarbonate levels and
alkaline pH values,these natural waters appear to
have sufficient assimilative capacity to mitigate
effects from potential acid rain events.
(e)Hydrologic Impacts
Impacts to the hydrological regime of ground and surface
water resources can result from the physical placement of
the power plant and its associated facilities,and from the
specific location and operation of a generating plant1s
intake and di scharge structures.The siting of the power
plant may necessitate the el imination or diversion of sur-
face water bodies and will modify the area1s runoff pattern.
Stream diversion and flow concentration may result in in-
creased stream channel erosion and downstream flooding.
Proper site selection and design can minimize these impacts.
If,after siting,local ized impacts remain a concern,vari-
ous mitigative techniques such as runoff flow equalization,
runoff energy dissipation,and stream slope stabilization
may be employed.
Other hydrological impacts can result from the siting and
operati on of the power pl ant·s makeup water system and
wastewater di scharge system.The physical pl acement of
these structures can change the local flow regime and
possibly obstruct navigation in a surface water body.
Potenti al impacts associ ated with these structures are gen-
erally mitigated,however,through facility siting and
structure orientation.Discharge of power plant wastewaters
may create localized disturbances in the flow regime and
velocity characteristics of the receiving water body.This
potential problem is minimized through proper diffuser
design,location,and orientation.Consumptive water losses
associated with the power plant may also affect hydrological
regimes by reducing the downstream flow of the water
resource.However,as discussed previously,surface water
supplies in the Railbelt region are plentiful.Hydrologic
impacts due to reduced streamflow shoul d therefore not be
significant.
(f)Land Use and Aesthetic Impacts
Fossil fuel power plants should be built in areas designated
for industrial develolJllent.This would result in no land
use or aesthetic impacts inconsistent with the designated
use.The presence of the plant would result in an aesthetic
impact,but this should be consistent with the land use
designation.
E-IO-150
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4.4 -Nuclear Steam Electric Generation
Nuclear steam electric generation is a mature,commercially available
technology.At present,some 73 units with a total installed capacity
of 54,000 MWe are operable in the United States.An additional 104
units representing approx imately 116,000 II1We of capacity have either
been ordered or are in some phase of the licensing or construction pro-
cess.Canada,France,Germany,Japan,Sweden,and the United Kingdom
also have a large nuclear steam electric capacity based either on u.S.
developed technology or on technologies developed within those respec-
tive countries.
In spite of this impressive backlog of experience,nuclear power is
experiencing social and political problems that might seriously affect
its viabil ity.These problems manifest themsel ves in 1 i censing and
permit delays,and are thus of significance to the Alaskan electrical
supply situation given their cost and schedule impacts.
Diminished load growth rates,concerns over nuclear weapons prolifera-
tion,adverse public opinion fueled by the Three-Mile Island accident,
expanding regulatory activity,and lack of overt support at the highest
polltical levels have all resulted in no new domestic orders for
nuclear units since 1977.The industry is currently maintaining its
viability through completion of backlog work on domestic units and by
pursuing new foreign orders.
The state of Alaska1s policy on nuclear power is expressed in the
legislation establ ishing the Alaska Power Authority.The Power Author-
ity may not develop nuclear power plants.
4.4.1 -Siting and Fuel Requirements
Nuclear plant siting has more constraints than other technologies
because of stringent regulatory requirements resulting from the
potential consequences of accidents involving the release of
radioactive materials.These requirements alone,however,would
not be expected to bar the development of nuclear power in
Al aska.
Under the siting criteria of the Nuclear Regulatory Commission
(10 CFR 100),nuclear facilities must be isolated to the degree
that proper exclusio~areas and low population zones may be main-
tained around the facil ity.Nominal distances ranging from 2000
to 5000 feet (600 to 1500 m)to the nearest boundary [encompas-
sing areas of 250 to 2000 acres (lao to 800 ha)J are typically
sufficient to meet the first criterion for almost any sized
nuclear facility.Additionally,a physical separation of 3 to 5
miles 5 to 8 km)from areas of moderate population density allows
compliance with the second criterion.These requirements are of
little real consequence in the present case,considering the low
population densities existing in the Railbelt region.
E-1O-151
4.4 -Nuclear Steam Electric Generation
Seismic characteristics of a potential site are a major factor in
plant siting since the nuclear plant must be designed to
accommodate forces that result from earthquake acti vi ty.Total
exclusion of nuclear plants on this basis is not indicated since
nuclear plants have been designed and constructed on a worldwide
basis in each of the seismic zones found in the Railbelt region.
In additi on to meeting the s peci fi c nuclear safety requi rements
of the U.S.Nuclear Regulatory Commission.a nuclear plant site
must meet the more typical criteria required of any large steam-
electric generation technology.A 1000-MW nuclear project
represents a maj or long-term construct i on effort.i nvol vi ng the
transportation of bulky and heavy equipment and large quantities
of construction materials.Means of transportation capable of
handling these items limit the potential Railbelt sites to the
corridor along the Al aska Rail road and port areas of Cook Inlet
and Prince William Sound.As noted previously.it is necessary
to site a nuclear plant in an area of low population density.
This requirement for remote siting must be balanced against the
cost of transmission facilities required to deliver power to
high-density population areas and load centers.
The heat rejected by a 1000-MW plant is substantial;a potential
site must thus have a sufficient supply of cool ing water to
remove the heat in a manner complying with environmental criteria
for thermal discharges.Once-through cool ing of a 1000-MWe
facil ity requires a water flow of approximately 3000 cfs and
would almost certainly require coastal siting.Closed cycle
systems requi re 1 ess water than once-through systems (probably
less than 100 cfs).thus expanding the range of siting options to
some of the rivers of the region.
Reactor fuel.a highly refined form of enriched uranium fabri-
cated into comp 1ex fuel el ements.is not produced in Al aska and
would have to be obtained from fuel fabrication facilities loca-
ted in the western portion of the United States.The proximity
of the nuclear plant to the fuel source is rel atively unimportant
compared to fossil-fired and geothermal plants.Uranium is a
high-energy density fuel,and refueling is accomplished on a
batch rather than a continual basis.Refueling is required about
once a year and is usually scheduled during summer months in cold
cl imates to prevent weather-i nduced del ays and to occur duri ng
periods of low electrical demand.
Current estimates indicate known uranium supplies are sufficient
to fuel only those reactors now in service or under construction
for their estimated lifetime.However,the latest nuclear
designs are capable of being fueled by plutonium as well as
uranium,and assuming that breeder reactors.producing surplus
fuel-grade plutonium.become commercial,then long-term fuel
E-1O-152
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4.4 -Nuclear Steam Electric Generation
supply shoul d not be a 1imiting factor.Al though Al ask a has
identified uranium deposits,the economic forces for developing
the resource are tied to the world market conditions rather than
to the use of uranium as fuel for nuclear plants located in
Al aska.
4.4.2 -Environmental Considerations
Water resource impacts associated with the construction and
operation of a nuclear power plant are generally mitigated
through appropriate plant siting and a water and wastewater
management program.It should be noted,however,that due to the
large capacities required for nuclear power stations (1000 MW),
the magnitude of water withdrawal impacts associated with a given
site may be greater than for other baseload technologies.Magni-
tude,however,does not necessarily imply significance.A favor-
able attribute of nuclear power is the lack of wastewater and
solid waste associated with fuel handling,combustion,and flue
gas treatment experienced in other combustion steam cycle tech-
nologies.
Nuclear power plants cause no deterioration in the air q~ality of
the locale,other than the routine or accidental release of
radionuclides.To assess the potential dosages of these radio-
active materials,a complex meteorological monitoring program is
required •.The wind speeds and dispersive power of the atmosphere
playa crucial role in diluting the effluent.Generally,sites
in sheltered valleys.and near population or agricultural centers
are not optimal from a meteorological point of view.Large
amounts of heat are also emitted by nuclear power plants.Some
modification of microclimatic conditions onsite will be noted,
but these modifications will be imperceptible offsite.The U.S.
Nuclear Regulatory Commission will ensure that the ambient
meteorological conditions are properly measured and considered in
the siting of a nuclear power plant.·These constraints will not
preclude the construction of such a facility at many locations in
the Railbelt region.
In addit i on to the effects on aquat ic and mari ne ecosystems
resulting from cooling water withdrawal and thermal discharges
common to other steam cycle plants,nuclear facilities have the
potential for routine low level and possibly accidental higher
level discharge of radionuclides into the aquatic environment.
The minimum size for a nuclear facility (1,000 MW)indicates that
these plants would be the largest water users of any steam cycle
plants,using approximately 310,000 gpm for once-through cooling
systems and 6200 gpm for recirculating cooling water systems.
Their rate of use (gpm/MW)is also higher than many other tech-
nologies because of somewhat lower plant efficiencies.Potential
impi ngement and entra i nment impacts wourd therefo re be somewhat
E-10-153
4.4 -Nuclear Steam Electric-Generation
higher than for other baseload technologies of comparable size.
Detrimental effects of discharge may also be high because of the
large quantity of water used.But the discharge water may have
fewer hazardous compounds than may be found in other steam cycle
wastewaters.
The predominant biotic impact on terrestrial biota is habitat
loss.Nuclear power plants require land areas (l00-150 acres)
second in size to those of coal-and biomass-fired plants.Fur-
thermore,lands surrounding the plant island are at least tempor-
arily modified by ancillary construction activities (i.e.,lay-
down areas,roads,etc.).Partial recovery of these lands could
possibly be accomplished through revegetation.Other impacts
difficult to mitigate could be accidental releases of radio-
nuclides.The effects of such accidents on soils,vegetation,
and animals could be substantial.However,proper plant design
and construction should prevent these emissions.One positive
feature of nuclear power is the absence of air pollution
emissions and resulting effects on biota.
Nuclear plants,particularly if cooling towers are used.have the
potential for significant aesthetic impacts.If the plant is
built in an area where the designated land use is for industrial
development.aestheti c 1and use impacts shoul d not be greater
than for other industrial uses.
4.4.3 -Potential Application in the Railbelt Region
Fuel availability and siting constraints would probably
not significantly impair construction of commercial
nuclear power plants in Alaska.Potential sites,how-
ever,would have to be near existing or potential port
facilities or along the Alaska Railroad because of the
need to del i ver 1 arge amounts of construction materi al
and very large and heavy components to the site.
Interior siting would have more favorable seismic condi-
tions.
More constraining than site availability is the rated
capacity of available nuclear units in comparison with
forecasted electrical demand in the Railbelt region.The
Railbelt system.with a forecasted interconnected load of
1550 MW in 2010,wi 11 probably be too small to accom-
modate even the smaller nuclear power units.primarily
from the point of view of system reliability.If nuclear
power were available to the Railbelt system.significant
reserve capacity would still have to be available to pro-
vide generating capacity during scheduled and unscheduled
outages.
E-10-154
....
4.5 -Biomass
In addition,the large capacity of most current nuclear
units limits the adaptability to growth to very large
increments,which are not characteristic of projected
Railbelt demands.Nuclear capacity is not added easily,
because strict licensing,construction,and operation
process must be followed.
4.5 -Bi omass
Biomass fuels potentially available in the Railbelt region for power
generation include sawnill residue and municipal waste.Biomass fuels
have been used in industrial power plants for many years.Biomass
plants are distinct from fossil-fired units in that maximum plant capa-
cities are relatively small;in addition,they have specialized fuel
handl ing requi rements.The generally accepted capacity range for
biomass-fired power plants is approximately 5 to 60 MW (Bethel 1979).
The moisture content of the fuel,as well as the scale of operation,
introduces thermal inefficiencies into the power plant system.
4.5.1 -Siting and Fuel Requirements
Biomass fuels are generally inexpensive but are characterized by
high moisture content,low buH densities,and modest heating
values.Typical net heating values of biomass fuels are compared
to coal below:-Fue 1 Btu/l b
Muni ci pal Waste 4000
Peat 4000
Wood 3500
Coal 9000
Since the supply of anyone biomass fuel may be insufficient to
support a power pl ant,provi s ions may have to be made for dual
fuel firing (e.g.,wood and municipal waste).For example,the
estimated supply of both wood and municipal waste biomass fuel in
Greater Anchorage will support a 19-MW power plant operating 24
hr/day at a heat rate of 15,000 Btu/kWh.
The rate of fuel consumption is a function of efficiency and
plant scale.Fuel consumption as a function of plant capacity is
presented below.
Pl ant Si ze Hourly Fuel Requirements Truck Loads
(Megawatts )(Tons)Per Hour
5 11
15 25 1
25 40 2
35 55 3
50 80 4
-E-10-155
4.5 -Biomass
Si ting requi rements for bi omass-fi red power pl ants are di ctated
by the condition of the fuel,location of the fuel source,and
cooling water requirements.Because biomass fuels are high in
moisture content and low in bulk density,economical transport
distances do not exceed 50 miles (80 km)(Tillman 1978).Biomass
power plants are thus typically sited at,or close to,the fuel
source and may function as part of a cogeneration system.Sites
must be accessible to all-weather highways since biomass fuels
are usually transported by truck.(Approximately four trucks per
hour would be required,for example,for a 50-MW plant.)
While proximity to the fuel source may be the most 1 imiting
factor,sites also must be accessible to water for process and
cool ing purposes.Land area requi rements are a function of
scale,extent of fuel storage,and other design parameters.
Typically,a 5-MW stand-alone power plant will require 10 acres
(4 ha);a 50-MW stand-alone plant will require 50 acres (20 ha).
Plants that
the fuel.
assu re fuel
weathe r.
use peat wi 11 requi re addit i ona 1 1and for ai r dryi ng
A 1-to 3-month fuel supply should be provided to
availability during prolonged periods of inclement
4.5.2 -Environmental Considerations
The burning of biomass could lead to significant impacts on
ambient air quality.Impacts arise largely from particulate
matter and nitrogen oxides emitted by the system.The emissions
of particulates can be well-controlled by using techniques such
as electrostatic precipitators or baghouses.The tradeoff bet-
ween emission controls and project costs must be assessed at each
facility,but wood burning facilities larger than about 5 MWe
will require the application of these air pollution control
systems.
Water resource impacts associated with the construction and
operation of a biomass-fired power plant are not expected to be
significant or difficult to mitigate in light of the small plant
capacities that are considered likely.
Potentially significant impacts to aquatic systems from biomass
plants are similar to other steam cycle plants and result from
the water withdrawal and effl uent discharge.Although these
plants are second only to geothermal facil ities in rate of water
use (730 gpmjMW),their total use for a typical plant would only
exceed that of oil and natural gas-fired plants because of the
small size of prospective plants.Approximately 18,250 gpm and
362 gpm would be requi red for once-through and recirculating
cooling water systems,respectively.Proper siting and design of
intake and discharge structures could reduce these impacts.
E-I0-156
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4.5 -Biomass
The major impact on the terrestrial biota is the loss or modifi-
cation of habitat.Land requi rements for bi.omass-fi red p1 ants,
approximately 50 acres (20 hal for a 50-MW plant,are similar to
coa1-fi red plants,and are generally i ntermedi ate between those
for nuclear and the other steam cycle power plants.
Potential primary locations of biomass-fired power plants in the
Railbe1t region are near Fairbanks,Soldatna,Anchorage,and
Nenana.Lands surrounding these five areas contain seasonal
ranges of moose.Waterfowl also inhabit these areas with high
use occurring along the Matunuska and Susitna River deltas near
Anchorage,and areas around Nenana.The Soldatna region also
contains populations of black bear and caribou calving,migration
corridors,and seasonal ranges.Populations of mountain goats,
caribou,and Dall sheep occupy habitats in the Susitna and
Matunuska River drainages near Anchorage.Impacts on these ani-
mal populations will depend on the characteristics of the speci-
fic site and the densities of the wildlife populations in the
site area.Due to the relatively small plant capacities invol-
ved,however,impacts should be minimized through the plant sit-
i ng process.'
Aesthetic and land use impacts would be typical for small power
plant development.Careful planning and construction of the
plant in areas designed for industrial use should minimize the
impacts.
4.5.3 -Potential Applications in the Rai1be1t Region
Potential sources of biomass fuels in the Rai1be1t region include
peat,mill residue from small sawmills,and municipal waste from
the cities of Fairbanks and Anchorage.
Fuel avail abil ity for wood resi due and muni ci pal waste in the
Railb~t region is shown in Table E.I0.36.
Only broad ranges of wood residue availability have been devel-
oped,since little information is available on 1umber~production
as a function of markets,lumber recovery,and internal fuel mar-
kets.Volumes of municipal waste have been identified from stu-
di es of refuse recyc1 i ng in the Anchorage area (Nebesky 1980).
Fuel supplies for a wood or municipal waste-fired biomass plant
may be sufficient in greater Anchorage,but marginal in Fairbanks
or the Kenai Peninsu1 a.Peat deposits are substantial but many
other fuels are available which compete economically with peat.
Biomass power plants in the Rai1be1t region may potentially con-
tribute 0.5 percent to 5 percent of future power needs.As such,
4.6 -Geothermal
the bi omass-fi red units woul d be central stat i on install at ions
capable of serving individual community load centers or
interconnection to a Railbelt power grid.
Since the biomass-fired systems are relatively small,they are
part i cul arly adaptabl e to the modest incremental capacity needs
forecast for the Railbelt region.
4.6 -Geothermal
Geothermal energy is defined as the heat generated within the earth1s
crust tapped as an energy source.Geothermal energy may be uti 1 ized
for electricity generation,which usually requires temperatures of at
least 280°F,or for direct applications at temperatures less than
280°F.Direct heating applications include space heating for homes and
businesses,applications -in agriculture and aquaculture,industrial
process heating,and recreational or therapeutic use in pools.
Approximate required temperatures of geothermal fluids for various
applications is presented in Table E.10.37.
Three types of geothermal resources hol d potential for development:
hydrothermal,geopressured brine,and hot dry rock.Only hydrothermal
systems are in commercial operation today.All three can provide a
source of energy which is immune to fuel price escalation.Although
hot dry rock resources represent over half the U.S.geothermal poten-
tial,satisfactory technologies have not yet been developed for extrac-
ting heat from this resource.Hydrothermal geothermal resources are
classified as vapor-dominated or liquid-dominated systems.A typical
vapor dominated system produces saturated to slightly superheated steam
at pressures of 435 to 500 psi and temperatures of approximately
450°F.
Liquid-dominated systems may be subdivided into two types,those
producing high enthal py fluids greater than 200 calories/gram (360
Btu/lb),and those producing low enthalpy fluids less than 200
cal ori es/gram.The hi gh enthal py fl ui ds may be used to generate
electrical power;the lower enthalpy fluids may be useful for direct
heating applications.
Wells drilled into high enthalpy,liquid-dominated systems produce a
mixture of steam and water.The steam may be separated for turbine
operation to produce electricity.
4.6.1 -Siting Requirements
Geothermal plants are always located at the site of the
geothermal resource.The four most important siting criteria
used to evaluate geothermal resources for application to electric
power production are:
E-10-158
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4.6 -Geothermal
-Fluid temperatures in excess of approximately 140°C (280°F);
-Heat sources at depths less than 10,000 ft with a temperature
gradient at 25°F per 1000 ft;
-Good rock permeabil ity to allow heat exchange fluid to flow
read ily;and
-Water recharge capability to maintain production.
Individual geothermal wells should have a capacity to supply 2 MW
of electricity.The power station's long-tenn viability is
dependent on the prediction of reservoir energy capacity and
management of reservoir development.
The site must have access available for construction,operation,
and mai ntenance personnel,and a source of water avai 1abl e for
condenser cooling (and injection in the hot rock technology).
The 1and a rea requi red for the e 1ectri cal generati ng and
auxiliary equipment portion of a geothermal plant will be similar
to that required for an oil-fired unit;however,the total land
area will be vastly larger because of the diffuse location of the
wells.A 10-MW plant,excluding wells,can be situated on
approximately 5 acres (2 ha)of 1 and.After exploratory well s
a re sunk to determi ne the most product ive 1ocat ions (both for
production and injection wells),the plant would be located based
on minimum cost of pipelines and other siting factors.A network
of piping would then be established to complete the
installation.
4.6.2 -Envi rorimental Impacts
A problem unique to geothermal steam cycles involves the water
quality characteristics of the geothennal fluid and the sub-
sequent disposal method.This fluid is generally saline and,
because of this characteristic,most geothermal plants in the
United States mitigate this potential problem through reinjection
into the geothermal zone.If the geothermal zone is highly pres-
surized,however,not all of the brine may be reinjected,and
alternative treatment and disposal methods must be considered.
For geothermal fields located in the Chigmit Mountains,brine
disposal in Cook Inlet should not prove to be too difficult.The
interior fields,however,could require extensive wastewater
treatment facilities to properly mitigate water quality impacts
to freshwater resources and comply with all relevant Alaska regu-
lations.Depending upon a specific field's water quality charac-
teristics,the costs associated with these treatment facilities
could also preclude development.
4.6 -Geothermal
Geothermal plants have the highest per megawatt water use of any
steam cycle plant (845 gpmjMW).A maximum size plant for the
Railbelt region (50 MW)would use less water than only nuclear-
fired or coal-fired plants,with a total water use rate of 42,200
gpm or 750 gpm for once-through and recirculating cooling water
systems,respectively.
Emissions of gases and particulates into the atmosphere from the
development of geothermal resources wi 11 consist primari ly of
carbon dioxide and hydrogen sulfide (H2S).Other emissions may
consist of ammonia,methane,boron,mercury,arsenic compounds,
fine rock particles,and radioactive elements.There is consider-
able variability in the nature and amount of these emissions,and
this uncertainty can be removed only by testing wells in the pro-
posed project area.Emissions are also a function of operational
techniques.If the reinjection of geothermal fluids is used,
emi ssions into the atmosphere may be reduced to nearly zero.
Even when reinjection is not used,H2S emissions can be con-
trolled by oxidizing this compound to sulfur dioxide (S02)and
subsequently using conventional scrubber technology on the pro-
duct gases.Emissions may also be controlled in the water stream
by an "i ron catalyst"system or a Stretford sul fur recovery unit.
Emissions of gases and particulates into the atmosphere from the
development of geothermal resources wi 11 consi st primari ly of
carbon dioxide and hydrogen sulfide (H2S),Other emissions may
consist of ammonia,methane,boron,mercury,arsenic compounds,
fine rock particles,and radioactive elements.There is consider-
able variability in the nature and amount of these emissions,and
this uncertainty can be removed only by testing wells in the pro-
posed project area.Emissions are also a function of operational
techniques.If the reinjection of geothermal fluids is used,
emissions into the atmosphere may be reduced to nearly zero.
Even when reinjection is not used,H2S emissions can be con-
trolled by oxidizing this compound to sulfur dioxide (S02)and
subsequently using conventional scrubber technology on the pro-
duct gases.Emissions may also be controlled in the water stream
by an "iron catalyst"system or a Stretford sulfur recovery unit.
Efficiencies of these systems have ranged as high as 90 percent
H2S removal.At the Geysers generating area in California,
H2S concentrat ions average 220 parts per mill i on (ppm)by
wei ght.The power plants emit about 3 1bjh r of H2S per mega-
watt of generating capacity.Regulation of emissions of other
toxic compounds can be controlled by various techniques as stipu-
lated by the regulations governing the specific hazardous air
poll utants.Control of hazardous poll utants will probably not
preclude the development of geothennal resources in the Railbelt
region.
E-10-160
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4.6 -Geothermal
In add it i on to major potent i a1 impacts associ ated with water
withdrawal and effluent discharge that are similar for all steam
cycle plants,geothermal plants have some unique problems that
may ha ve hazardous effects on the aquati c envi ronment.Geot her-
mal water is often high in slats and trace metal concentrations,
and is often caustic.The caustic nature of the sol ution often
corrodes pipes,which can add to the toxic nature of the brine.
Current regulations require reinjection of spent geothermal
fluid;however,entry of these brine solutions into the aquatic
environment by discharge,accidental spills,or ground water
seepage could cause acute and chronic water quality effects.
One of the major geothermal potenti a1 areas in the Ra i1bel tis
located in the Wrangell Mountains near Glennallen.This area
drains into the Copper River,which is a major sa1monid stream.
The result of accidental discharge of geothermal fluids into this
system may have significant impacts on these fish,and other
aquatic organisms,depending on the size and location of the
release.
Other large geothermal areas,including Mt.Spurr,are in the
Chigmit Mountains on the west side of Cook Inlet.Much of this
area is close to the marine environment.In general,geothermal
waters wou1 d have 1ess detrimental effects on marine organisms
(because of their natural tolerance to high salt concentrations)
than on fresh water organisms..
The primary impact resulting from geothermal plants on the
terrestrial biota is habitat loss.Land requirements for geo-
thermal plant facilities,on a per-kilowatt basis,are comparable
to those for oil and natural gas plants.Biomass,coal,and
nuc1 ear plants require 1 arger tracts of 1 and than geothermal,
either from the standpoi nt of capacity or ki 1owatt product ion •
However,geothermal lands are more likely to be located in remote
areas than other steam cycle power plants.Disturbances to these
areas could be extensive depending on the land requirements of
the geothermal well field.
Primary geothermal development locations are within the Wrangell
and Chigmit Mountains.The latter area is remote and is inha-
bited by populations of moose and black bear.The Wrangell
Mountain area is generally more accessible and includes popula-
tions of moose,Oa11 sheep,caribou,and possibly mountain goats.
Impacts could be greatest in remote areas since an extensive road
network would have to be built to service the well field.Roads
would cause the direct destruction of habitat and also impose
additional disturbances to wild1 ife and vegetation from increased
accessibility to people.
E-10-161
4.6 -Geothermal
Because geothermal plants must be located where the energy source
is,the potential for land use and aesthetic impacts is high.A
prime consideration in project planning is whether the plant can
be developed and made compatible with existing land uses and not
detrimentally affect the aesthetic environment.
4.6.3 -Potential Application in the Railbelt Region
Only hot dry rock (hot igneous)and low-temperature,liquid-
dominated hydrothermal convection systems have been identified in
or near the Railbelt region.Some low-temperature geothermal
resources in the Fa i rbanks area a re used for heat i ng swimmi ng
pool s and for space heating.In southwest Al aska some use is
made of geothermal resources for heating greenhouses as well as
space heati ng.Hot dry rock geothermal resources with tempera-
tures that may be hi gh enough to generate electricity have been
di scovered in the Wrangell and Chiglllit Mountains.The Wrangell
system,located approximately 200 mil es (320 km)from Anchorage,
has subsurface temperatures exceeding 1200°F.The Chigmit
System,to the west of Cook Inlet,is isolated from the load cen-
ters by 200 miles (320 km)of rugged terrain.Little is known
about the geothermal properties of either system.The Al aska
Department of Natural Resources has a geothermal lease in the
Mount Spurr area planned for May 1983.However,until explora-
tion of the geothermal properties of Mt.Spurr has occurred,the
viability of geothermal power for the Railbelt region is
unknown.
A geothermal resource in granite rock has been identified in the
Willow area.A deep exploration well was discovered to have a
bottom hole temperature of 170°F.Exploration data to date indi-
cate that,while this resource may prove useful for low tempera-
ture applications,its relatively low temperature makes it an
unlikely source for electric generation.
The geothermal areas (with the exception of Mt.Spurr)of both
Wrangell and Chigmit Mountains are located in lands designated as
National Parks.The federal Geothermal Steam Act prohibits
leasing and developing National Park lands.If,however,town-
ships within these areas are selected by a Native corporation
under the Alaskan Native Claims Settlement Act,and if the sur-
face and subsurface estates are conveyed to private ownership,
then the federal government jurisdiction would not apply,and
development could be possible.The Alaska National Interest
Lands Conservation Act of 1980 allows the granting of rights-of-
way for pipelines,transmission lines and other facilities across
Nat i ona 1 Interest Lands for access to resources surrounded by
National Interest Lands.
E-10-162
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4.7 -Wind
Until the mid 1930s,wind energy supplied a significant amount of
energy to rural areas of the United states.With the advent of rural
electrification,wind energy ceased to be competitive with other power
alternatives.However,rising fuel costs and the increased cost of
power from competing technologies has renewed interest in the develop-
ment of wind resources.This energy source may come to playa signifi-
cant role in electric power generation in rural areas,small commu-
nities,and possibly for large interconnected energy systems~
4.7.1 -Large Wind Systems
Large wind turbines are being developed in response to this
renewed interest and are in a demonstration phase.In 1979,a
MOD-I,2-MW,200-ft (60-m)diameter turbine was completed at
Boone,North Carolina.Three MOD-2 wind turbines,rated at
~.5-MW capacity,are under construction near Goldendale,Washing-
ton by the Bonneville Power Administration,U.S.Department of
.Energy,and NASA.These and other wind turbines in the 1-MW
range of rated output are avail abl e for producti on,but benefits
of assembly line production have not been realized.Commercially
available,mass produced wind machines are at present quite small
and only available in unit sizes of about 5 kW,with the maximum
at 45 kW.This section will focus on large wind turbines of 0.1
MW rated capacity or more such as might by employed as centra-
lized power generating facilities by a utility.
-
-
(a)
(b)
Siting Requirements
The siting of the wind turbines is crucial in wind energy
conversion systems.The most significant siting considera-
tion is average wind speed and variability.These depend on
large-scale weather patterns but are also affected by local
topography,which can enhance or reduce the average wind
speeds.Since wind energy potential is directly propor-
tional to the cube of the wind speed,siting wind machines
to take advantage of even small incremental increases in
wind speed is important (Hill 1977).Extremely high winds
and turbulence may damage the wind turbines,and any sites
exhibiting these characteristics must be avoided.
Other important siting considerations include the proximity
of the site to load centers,site access,founding condi-
tions,and meteorological conditions.Undesirable meteoro-
logical conditions in addition to turbulence include glazing
conditions,blowing sand or dust,heavy accumulations of
snow,and extreme cold.
Environmental Considerations
Wind turbines extract energy from the atmosphere and there-
fore have the potential to cause slight modifications in the
E-I0-163
4.7 -Wi nd
surrounding climate.Wind speeds will be slightly reduced
at surface levels and to a distance equivalent to five rotor
diameters~which for a single 2.5-MW facility would be
approximately 1500 ft (450 m).Small modifications in
precipitation patterns may be expected~but total rainfall
over a wide area will not be affected.Nearby temperatures~
evaporation~snowfall~and snow drift patterns will be
affected only slightly.The microclimatic impacts will be
qualitatively similar to those noted around large isolated
trees or tall structures.
The rotation of the turbine blades may interfere with tele-
vision~radio~and microwave transmission.Interference has
been noted within 0.6 miles (1 km)of relatively small wind
turbines.The nature of the interference depends on signal
frequencies~blade rotation rate~number of blades~and wind
turbine design.A judicious siting strategy could help to
avoid these impacts.
Stream siltation effects from site and road construction are
the only potential aquatic and marine impacts associated
with this technology.Silt in streams may adversely affect
feeding and spawning of fish~particularly salmonids which
are common in the Railbelt region.These pote'ntial problems
can be avoided by proper construction techniques and should
not be significant unless extremely large wind farms are
developed.
Wind-powered energy requi res varying amounts of land area
for development.The amounts of area required depend on
number~spacing~and types of wind-powered units used.This
can range from approximately 2 acres (.8 ha)for one 2.5-MW
generat i ng unit to over 100 square mil es (260 km 2)for a
1000-MW wind farm.These developments~due to requirements
for persistent high-velocity winds~would probably be estab-
lished in remote areas.
Because of the land requirements involved~the potentially
remote siting locations~and the possible need for clearing
of vegetation~the greatest impact resulting from wind
energy projects on terrestrial biota would be loss or dis-
turbance of habitat.Wind generating structures could also
affect migratory birds by causing collisions.Other poten-
tial impacts include low frequency noise emanating from the
generators and modification of local atmospheric conditions
from air turbulence created by the rotating blades.The
impacts of these latter disturbances on wildlife~however~
are presently unclear.
E-10-164
4.7 -Wind-
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Environmentally sensitive areas in the Railbelt region pre-
sently proposed for wind energy development are exposed
coastal areas along the Gulf of Alaska,and possibly hill-
tops and ridgelines in the interior.Alteration of coastal
bl uffs could negatively affect seasonal ranges of mountain
goats of the Kenai Mountain Range,and nesting colonies of
sea birds in the Chugach Islands,Resurrection Bay,Harris
Bay,Nuka Pass,and other areas along the Gulf Coast.
Shoreline development could affect harbor seals and migra-
tory birds.Harbor seals utilize much of the coastline for
hauling-out.The Copper River Delta is a key waterfowl area.
Scattered use of shoreline habitat by black bear,brown
bear,and Sitka blacktailed deer occurs in Prince William
Sound.The presence of wind energy structures in any of
these areas could potentially cause collisions with migrat-
ing waterfowl,bald eagles,peregrine falcons (endangered
species),and other birds,if situated in migratory corri-
dors.Inland development of wind energy could negatively
affect Dall sheep,mountain goat,moose,and caribou if
situated on critical range lands.
These terrestrial impacts can generally be mitigated by sit-
ing plants in areas of low wildlife use.This would include
avoiding critical ranges of big game,traditional haul-out
areas of seals and nesting colonies of birds,and known mi-
gratory bird corridors or key feeding areas.The feasibil-
ity of mitigation will,of course,depend on the size of the
wind energy development.
The need for high velocity winds and large land requirements
could result in wind power stations being developed in re-
mote areas.This has potential for land use and aesthetic
impacts,particularly in the area of recreation.Careful
planning would be required in facility siting to reduce.or
avoid these impacts.
(c)Potential Application to Railbelt Energy Demand
-A wind-turbine system consisting of five machines has been
installed at Gambell on St.Lawrence Island in Alaska to
provide wind electric power for community facilities.An-
other wind turbine has been installed at Nelson Lagoon on
the Alaskan Peninsula.
Studi es to identify wi nd energy resources in the Ra i1 be It
,-would require a significant data base.Such a data base
currently is lacking.Currently available literature is not
adequate to comprehensively identify potential wind t:nergy
conversion system sites in the Railbelt region.Studies
E-10-165
4.7 -Wind
necessary to assess wind energy potential include preparing
and examining detailed contour patterns of the terrain,
modeling selected sites,monitoring meteorological condi-
tions at prime sites for at least one year (preferably three
years),porforming analyses using modeled and measured data,
developing site-specific wind duration curves,and selecting
final sites.
The University of Alaska has conducted a preliminary assess-
ment of wind power potential in Alaska.The results of
these studies indicated a potential for favorable sites for
wind energy development at exposed coastal locations and
possibly along ridgelines or hills in the interior
(Battelle/EBASCO 1981).
4.7.2 -Small Wind Systems
Small wind energy conversion systems (SWECS)are wind machines
with rated output of 100 kW or less.Typically these machines
would be sited in a dispersed manner,at individual residences,
or in small communities,as compared to the large wind energy
conversion systems which would be sited,generally in clusters,
as centralized power production facilities.
Small wind energy conversion systems are available in horizontal
and in vertical axis configuration.The horizontal areas·mach-
ines exhibit superior efficiency but require a substantial tower
to support the generating equipment as well as the blades.In
addition,the blade/generator assembly must revolve in conform-
ance with changing wind direction,requiring provision of head
bearings and slip rings and machine orientation devices.
Although of lower efficiency than horizontal axis machines,the
vertical axis generator is located in a fixed position near the
ground,minimizing tower structure and eliminating the need for
head bearings or slip rings.Because of these advantages,verti-
cal axis machines may exhibit superior cost characteristics in
the small wind machine sizes.
A number of small wind machines are now in commercial production
in sizes ranging from O.lto 37 kW.
Historically,battery-charging systems have been the primary
application for Small Wind Energy Conversion Systems in Alaska;
however,this is beginning to change.
The subj ect of thi s study has been concerned with SWECS whi ch
interface directly with the utility grid.Off-grid installations
were not considered.
E-I0-166
r-:-'
.....
4.7 -Wind
(a)Siting Requirements
A wind speed of 7 to 10 mph (12 to 16 Kmh)is required ~o
start most SWECS producing power.An annual average of 10
mph (16 Kmh)is usually considered a lower economic cut-off
for most·applications;however,this is very dependent on
the site,energy costs,and particular wind generator de-
sign.
Turbulent energy is the worst for SWECS.It can be caused·
by trees,buildings,and topography.Because wind acts like
a fluid in that it slows down when it encounters an object
or rough terrain,wind speeds are greater at higher eleva-
tions.Thus each site must be evaluated for terrain and
what affect that may have on wind speeds at different
heights.
A small wind machine which is to be intertied to the utility
grid must be reasonably close to existing or planned power
lines.This requirement may eliminate many ridge tops be-
cause of the high transmission line losses.
-
-
-
-I
I
(b)Envi ronmental Impacts
Studies have shown some enhancement of local wildlife due to
downwind shelters,as well as a possible adverse impact on
low flying night migratory birds in bad weather.However,
the kill rate is not significant.
Aesthetic intrusiveness is difficult to assess and highly
subjective.Many people surveyed have found small wind
machines to be visually pleasing.Small generator noise is
not significant with proper blade design.
Small wind machines mounted on towers require no more than
100 sq ft (9 m2)at the base plus any exclusion area which
the owner wishes to fence off for safety reasons (usually no
more than about five blade diameters).Proper siting and
planning can reduce or el iminate land use or aesthetic
impacts.
Radio frequency interference can be mitigated with proper
blade design (nonmetallic)and siting.
Potential safety risks involve the possibil ity of tower or
blade failure and aircraft collision.Actions taken to
decrease those risks include:
E-I0-167
4.7 -Wind
-Maintenance of an exclusion area around the turbine;
-Automatic monitoring of turbine operation;
-Regular preventative maintenance;
-Visitor control measures;and
-Adherence to FAA requirements for tall structures.
(c)Potential Application to the Railbelt Region
Unti 1 recently there were only a handful of SWECS manufact-
urers.Today there are over 50,with a half dozen mass pro-
ducing generators at a respectable rate (20-200/month).
A dealership and repair network is already in existence in
the Railbelt region and would grow as the number of in-
stalled SWECS increases.Engineering and design expertise
is also present in the region.Five system design organiza-
tions,four suppl iers,and one installer were operating in
the Railbelt in 1981.
The major obstacl e to the avai 1abi 1 i ty of wi nd generators
seems to be the lack of venture capital in an unstable
economic climate,which makes needed plant expansion diffi-
cult for manufacturers.Once the market penetration and
mass production has brought the unit cost down and manufac-
turers have internalized major R&D efforts,then widespread
use of SWECS may become a reality.
Wind data have historically been collected from ai rports at
'a hei ght usually no greater than 30 ft (9 m).Wi nd gener-
ators are typically not located near airports (which are
usually sited in locations protected from winds)and are
placed at least twice as high as conventional meteorological
stations.A few examples will illustrate the problem:
The annual average recorded for Anchorage is 5 mph taken
at the international airport.Closer to the mountains at
the site of an installed wind generator the average is 6
mph.At Flat Top Mountain,a homeowner who plans to in-
stall a SWECS has recorded months of 15 mph averages.
In Homer the recorded annual average is 9 mph at the ai r-
port,whi 1e on the "spit"the average is reported to be
closer to 13 mph.Further up the hill at the site for an
18 kW SWECS,the winds have not been measured but are ex-
pected to be better than at the airport.
E-I0-168
-
.....
"
,....
I
i
-
-
-
4.8 -Sola r
-In Fairbanks the average is recorded as 4 mph,yet as one
climbs out of the valley the average wind speed almost
triples near Murphy Dome.
This suggests that existing data are not very helpful in de-
termining the potential of SWECS in the Railbelt.The num-
ber of mountain passes with channel ing effects,glaciers
with their constant source of winds,and coastal regions
with the windy maritime influences yield thousands of poten-
tial SWECS sites in the Rail belt.
Because of the 1ack of data taken for siting small wi nd
machines,there is no quantitative means for assessing the
possible contribution SWECS would have in the Rai"lbelt re-
gion.However,since most of the population lives in two
known areas of low winds (Anchorage and Fairbanks),it is
reasonable to assume that without large-scale utilization
of "wind farms,"only a small percentage of the total Rail-
belt load could be met by wind power (less than 10 percent)
in the next five years.If a decision were made to develop
clusters of SWECS,then this contribution could become sig-
nificant in the midterm (five to ten years).
4.8 -Solar
Two basic methods for generating electric power from solar radiation
are under development:solar thermal conversi on and photovolta ic sys-
terns.Solar thermal systems convert solar radiation to heat in a work-
ing fluid.This working fluid can include water,steam,air,various
solutions,and molten metals.Energy is realized as work when the
fluid is used to drive a turbine.Photovoltaic systems is a more
direct approach.Solar energy is converted to electric energy by the
activation of electrons in photosensitive substances.
At present,commercially available photovoltaic cells are made of sili-
con wafers and assembled 1argely by hand.Nearly two dozen technolo-
gi es and automatic assembly techni ques are under development.Photo-
voltaic technology is undergoing a burst of innovation comparable to
the integrated ci rcuit-semiconductor technology.New and more
efficient cell designs have been proposed capable of converting 30 to
40 percent of the sunlight falling on them to electricity.
Both solar technologies,suffer from the same constraints.Available
solar energy is diurnally and seasonally variable and is subject to
uncertainties of cloud cover and precipitation.Solar energy resources
must be ernployed as a "fuel saving"option or they must be installed
with adequate storage capacity.In addition,if the diurnal and annual
cycles are out of phase with solar energy demand cycles,the induce-
ments for development of this resource are further reduced.The energy
E-I0-169
1 I
4.8 -Sol ar
demand and solar ava"ilability cycles are out of phase in the Railbelt
region,where demand generally peaks in winter and at night.
4.8.1 -Siting Reguirements
Solar electric generating systems are optimally located in areas
with clear skies.The geographic latitude of the proposed site
also plays an important role in determining the intensity of
solar insolation.Low sun angles,characteristic of high lati-
tudes,provide less solar radiation per unit area of the earth1s
surface,requiring greater collector area to achieve a given
rated capacity.Increasing the "tilt"of collectors relative to
the surface of the earth increases the solar power density per
unit area of collector but results in shading of adjacent collec-
tion devices at low sun angles.These factors place severe con-
straints on the development of solar energy in the Railbelt
region.
In addition to the latitudinal and cloudiness constraints,poten-
tial sites must not be shaded by topographic or vegetative fea-
tures.This type of shading does not present a severe restric-
tion for development in the Railbelt region.The potential for
snow and ice accumulation also inhibits development of solar
ene rgy resou rces.
4.8.2 -Environmental Considerations
Photovoltaic systems do not require cooling water or other con-
tinuous process feedwater for their efficient operation.Small
quantities of water are required for domestic uses,equipment
cleaning,and other miscellaneous uses,but if standard engineer-
ing practice is followed,water resource effects should be insig-
nificant.If hot water cogeneration systems are employed in
conjunction with photovoltaic systems,continuous feedwater will
be required to offset system losses.In light of the small plant
capacities that would be considered for the Railbelt and the
absence of cool i ng water requ i rements,water resou rce effects
should be minimal.
The development of solar thermal conversion systems would produce
water resource effects simil,ar to other of steam cycle facil'i-
ties.Boiler feedwater and condenser cooling water will be
required and will necessitate proper management techniques.
Water requirements are extremely site-specific,since efficien-
cies ranging from 10 to 70 percent are possible depending upon
climatic factors.However,in light'of the small capacities
considered,impacts should not be significant.
Solar thermal conversion systems may also be operated utilizing a
working fluid other than water.Fluids such as liquid sodium,
E-I0-170
~,
-
4.8 -Solar
sodium hydroxide,hydrocarbon oils,and sodium and potassium
nitrates and nitrites have the potential to adversely affect
water qual ity through accidental spills and normal system flush-
ing.Specialized transportation and handling techniques will be
required to minimize spill risk and properly mitigate potential
impacts.
Water resource impacts would also occur if pumped storage faci1i-
ties were ut il i zed as the energy storage technology for either
photovo1taic or solar thermal conversion systems.
Solar thermal and photovo1taic electric power conversion systems
have no impact on ambient ai r qual ity because they do not emit
gaseous poll utants.Water vapor p1 umes may emanate from cool i ng
systems associated with solar thermal processes,however.These
p1 umes wi 11 be substanti ally reduced because sol ar thermal sys-
tems operate best in full sunlight when the air tends to be well
below saturation.The water droplets are quickly evaporated into
a dry atmosphere.The plumes can also be mitigated by using dry
or wet/dry cool ing tower systems.
Some modification of the microclimate will occur near a solar
energy facility.The heat is merely redistributed within the
facility and will not affect climatic conditions offsite.The
climatic response of these facilities will be similar to that of
any comparably large construction project.
Due to minimal water requirements,the operation of photovo1taic
systems will have insignificant impacts on fresh or marine aqua-
tic biota but solar thermal conversion plants may have impacts
simi1 ar to those of other steam cycle plants.These impacts,
however,should be small and easy to mitigate in 1 ight of the
small plant capacities considered.
The major terrestrial impact associated with photovoltaic or
solar thermal conversion systems is habitat loss.If these
systems are located in remote areas,the potential for wildlife
disturbance through increased human access may also be signifi-
cant.Spills of non-water working fluids,if used,could ad-
versely affect local ecosystems.In general,however,impacts to
the terrestrial biota of the Railbelt region should be minimal,
since power plant capacities for both photovo1taic and thermal
conversion systems will be small.In a similar manner,land use
and aesthetic impacts should be small.
4.8.3 -Potential App1 ication to the Railbelt Region
Data collected at Fairbanks and at Matanuska,near Anchorage,
reflect the influence of both cloudiness and the annual cycle in
4.8 -Sol ar
sun angle at these locations.At Fairbanks the total daily solar
radiation on a horizontal surface is 13 Btu/ft 2 in December-and
1969 Btu/ft 2 in June.At Matanuska these val ues range from 48
Btu/ft2 in December to 1730 Btu/ft 2 in June.In comparison,
in the arid southwestern United States,January val ues of 1200
Btu/ft2 are common,with many areas having July val ues over
2500 Btu/ft 2 •Even in less favored areas such as Minnesota,
these same val ues vary from 550 Btu/ft 2 to 2000 Btu/ft2 dur-
ing the year.These data indicate that whil e there is an abun-
dant supply of sol ar energy on a hori zonta1 surface in midsummer
in Alaska,the mid-winter values are an order of magnitude less
than those of even poor sites in the remainder of the country.
The obvious lack of sunshine in the winter restrains the develop-
ment of sol ar energy in the Ra i1 belt regi on.Even on south-
facing vertical walls,the daily total solar radiation in Mata-
nuska is only 300 Btu/ft 2 in December,which indicates that the
mere reori entat i on of co 11 ect i ng surfaces will not all evi ate the
siting constraint.
None of the existing or developing solar photovoltaic technolo-
gies represents an economically viable form of large-scale elec-
tric power generation in the Railbelt.Current systems provide
only a few watts of output and are not currently pl anned for
large-scale application.
E-I0-172
p--
-
5 -ENVIRONMENTAL CONSEQUENCES OF LICENSE DENIAL
Demand for electricity in Alaska is expected to grow into the future.
Should the FERC license for the Susitna Hydroelectric Project be
denied,the state of A1as~a or private utilities would have to pursue
other electrical power generating schemes.These other schemes would
necessarily include heavy reliance on thermal power and perhaps mul-
tiple hydroelectric facilities if the projected energy demand is to be
met.
If the Beluga coal fields were developed as a therlllal source of power,
the environmental impacts would be greater than the Susitna project.
Utilization of coal,a non-renewable resource,would involve strip min-
ing,air pollution from both fugitive dust and power plant emissions,
and water poll ut i on of both surface and g round waters.Mi ni ng waul d
result in large volumes of solid waste which would require disposal.
In addition,the climatic conditions of Alaska would make reclamation
activities difficult.
Use of oil would result in power costs being vulnerable to fluctuations
caused by international,pol itica1,and economic events.Transporta-
tion,storage,and combustion of oil all have the potential for air and
water pollution.Use of this oil would also preclude its use for other
purposes,such as gasol ine and heating fuel or for use to produce
electricity where no hydroelectric alternatives are available.
Natural gas,through utilization of the West Cook Inlet natural gas
fields,is another alternative to Susitna.Because of no solid waste
problems and less likelihood of air and water pol1utio~,natural gas is
a fossil fuel preferable to oi 1 or coal.However,as with all fossil
fuels,it is a non-renewable resource;ut,lization of it for electrical
generation precludes its use for heat,for industrial purposes,or for
generating electricity where no other sources are available.
The technology of bi omass,wi nd,sol a r,t i da 1,and geothermal ene rgy
generation is not developed enough to make these immediately feasible
in Alaska.Furthermore,the size of the facilities that would be re-
quired to produce the same power as Susitna would limit the practical-
ity of this application.
Nucl ear power is controversi al and expensi ve,with long del ays due to
regu1 atory and envi ronmental concerns a common occurrence.Al so,the
disposal of nuclear wastes is an unresolved technical problem.
A further alternative is the combination of a thermal generating plant
with hydroelectric facilities smaller than Susitna.This would result
in various environmental impacts in more than one location and include
increased access and air and water pollution from burning of fossil
fuel.This contrasts to the Susitna project,where only one area would
be disturbed and no degradation in air or water quality is expected.
E-10-173
5 -Environmental Consequences of License Denial
Thus,the Susitna project will supply the majority of Alaska's popula-
tion with a source of power generation that offers long term stability
in power costs with relative insulation from the influence of inflation
and fossil fuel prices dictated largely by international pol itical and
economic events.Further,the non-renewable fossil fuel resources
would be available for future use or for use in locations where hydro-
electric potential is unavailable.
Impacts would be restricted to the Susitna Basin,and the mitigation
measures described in previous chapters will substantially reduce there
impacts.
If the project is not built,potential benefits will be centered in the
Upper Susitna Basin where access road and transmission 1ine corridors
would remain in their natural state.Public access would remain limi-
ted,and establ ished wildl ife patterns would remain undisturbed.In
addition,the flow modification and thermal problem that might result
from the dams woul d not affect anadromous fi sh.
E-IO-174
i
References
Acres American Incorporated.1981.
Development Selection Report.
Authority.
Susitna Hydroelectric Project,
Prepared for the Al aska Power
-
1981a.Prel iminary Assessment of Cook Inlet Tidal Power,
Phase 1 Report.Prepared for the State of Alaska,Office of the
Governor.
1982.Susitna Hydroelectric Project,Feasibility Report.
Volume 1.Prepared for the Alaska Power Authority.
1982a.Susitna Hydroelectric Project,1980-81 Geotechnical
Report,Appendix F.Prepared for the Alaska Power Authority.
1982b.Access Route Recommendation Report.Prepared for the
Alaska Power Authority.
Acres American Incorporated/Terrestrial Environmental Specialist,Inc.
1982.Transmission Line Selected Route.Prepared for the Alaska
Power Authority.
Alaska Power Administration.1980.Hydroelectric.Alternatives for the
Alaska Railbelt.
Battelle Pacific Northwest Laboratories.
Assessment.The Impact of Increased
Pacific Northwest.Prepared for the
BNWL-RAP-21,UC-ll.
Natural Coal Utilization
Coal Consumption in the
u.s.Department of Energy.
1982.Railbelt Electric Power Alternatives Study:Evaluation
of Railbelt Electric Energy Plans.Prepared for the Office of the
Governor,State of Alaska.
Battelle Pacific Northwest Laboratories/EBASCO.1981.Beluga Coal
Report.Prepared for the Office of the Governor,State of Alaska.
Bechtel Civil and Minerals,Inc.1983.Chakachamna Hydroelectric
Project.Draft report prepared for the Alaska Power Authority.
Bechtel Civil and Minerals,Inc.1981.Chakachamna Hydroelectric
Project,Interim Report.Prepared for the Alaska Power Authority.
Bethel,J.S.et ale 1979.Energy'From Wood.A report to the U.S.
Congress,Office of Technology Assessment.Seattle,Washington.
College of Forest Resources,University of Washington.
Commerce and Economic Development,Division of Energy and Power
Development.1980.Alaska Regional Energy Resources Planning
Project Phase 2,Coal,Hydroelectric,and Energy Alternatives.
Volume 1 -Beluga Coal District Analysis.
References (Continued)
Cook Inlet Region,Inc.and Placer Amex,Inc.1981.Coal to Methanol
Feasibility Study,Beluga Methanol Project.Volume IV,
En vi ronmenta 1•
Cook Inlet Region,Inc.and Placer Amex,Inc.1981a.Coal to Methanol
Project,Final Report.Volume IV.
Hill,P.G.1977.Power Generation.Cambridge.MIT Press.
Nebesky,W.1980.An Economic Evaluation of the Potential for
Recycling Waste Materials in Anchorage,Alaska.Prepared for the
Institute of Social and Economic Research.
R&M Consultants.1982.Subtask 2.10 -Access Planning Studies.
Prepared for Acres American Incorporated.
1982a.Subtask 2.10 -Supplementary Access Planning Studies.
Prepared for Acres American Incorporated.
State of Alaska.1972.Knik Arm Highway Crossing.Department of
Highways,Anchorage.
Ti llman,D.A.1978.Wood as an Energy Resource.New York.Academic
Press.
u.S.Department of Energy.1980.Hydroelectric Alterntives for the
Alaska Railbelt.Prepared for Alaska Power Administration,
Juneau.
u.S.Fish and Wildlife Service.1962.Unpublished letter to Bureau of
Reclamation.
u.S.Fish and Wildlife Service.1978.Impact of Coal-Fired Power
Plants on Fish,Wildlife,and their Habitats.Biol Service
Program.
Wentink,T.,Jr.1979.Alaskan Wind Power Study.Conference and
Workshop on Wind Energy Characteristics and Wind Energy Siting.
1 1 1 )1 1 1 1 ~~-l
TABLE E.l0.l:SUMMARY OF RESULTS OF SCREENING PROCESS
EI imination Eli min at i on EI imination EI imlnation
Iteration Iteration Iteration I terat i on
1 1 1 1
Site 1 2 3 4 Site 1 2 3 4 Site 1 2 3 4 Site 1 2 3 4
All ison Creek Fox *Lowe *Tal achu I itna Ri ver *
Beluga Lower *Gakona *Lower Chu I I tna *Talkeetnna R.-Sheep *
Bel uga Upper *Gerstle *Lucy *Ta I keetna - 2
Big Delta *Gran i te Gorge *McC I ure Bay *Tanana River *
Brad I r:1Y Lake *Grant Lake *McKinley River *Tazl ina *
Bremner R.-Sa I roon *Greenstone *McLaren River *Tebay Lake *Bremmer R.-S.F.*Gulkana River *Mi I I Ion Do I Iar *Tekl an i ka *
Browne Hanaglta *Moose Horn *Tiekel River *
Bruskasna Hea Iy *Nel I Ie Juan River *Toklchitna *
Cache Hicks Nell I e Juan R.-Upper *Totatlanika *Canyon Creek *~River *Ohio *Tustumena *Car I bou Creek *John son *Power Creek *Vachon I s land *
Carlo *Junction Island *Power Creek - 1 *Whiskers *
Cathedral Bluffs *Kanhshna River *Ramport *Wood Canyon *
Chakachamna Kasi lof River *Sanford *Yanert - 2 *
Chul itna E.F.*Keetna Sheep Creek *Yentna *Chulitna Hurrican *Kenai Lake *Sheep Creek - 1 *
Chul itna W.F.*Kenai Lower *Silver Lake *
Cleave *Killey River *Skwentna *
Coal *King Mtn *Snow
Coffee *KI uti na *""SOTOmon Gu I ch *
Crescen t Lake *Kots ina *Stelters Ranch *
Crescent Lake - 2 *Lake Creek Lower *Strand line Lake
Deadman Creek *Lake Creek Upper *Summl t Lake *
Eag Ie Ri ver *Lane *Talachulitna *
--
Notes:
(1)Fi na I si te selection underl ined.
*Site eliminated from further consideration.
TABLE E.l0.2:
Site
Carlo
Yanert - 2
Healy
Lake Creek Upper
McKinley River
Teklan i ka
Cleave
Wood Canyon
Tebay Lake
Hanagita
Gakona
San ford
Cresent Lake
Kas i lof River
Mi II ion Dollar
Rampart
Vachon Is I and
Junction Island
Power Creek
Gu I kana
SITES ELIMINATED IN SECOND ITERATION
Criterion
Dena I I Nat I ona I Park,Nat iona I Par k Wi I derness
Denal i National Park
Wrangell-St.Elias National Park &Preserve,
National Park \'iilderness,Major Fishery
Wrangell-St.EI ias National Park &Preserve,
National Park Wilderness
Wrange I I -St.EI i as Nat iona I Park &Preserve
Lake Clark National Park
Major Fi s hery
Wild &Scenic River
-
Evaluation Criteria
(1)Big Game
TABLE E.l0.3:EVALUATION CRITERIA
General Concerns
-Protection of wildl ife resources
(2)Agricultural Potential
(3)Waterfowl,Raptors &
Endange-red Species
(4)Anadromous Fisheries
(5 )Wi I derness Consideration
(6)Cultural,Recreation
&Scientific Features
(7)Restricted Land Use
(8 )Access
-Protection of existing and potential
agricultural resources
-Protection of wildlife resources
-Protection of fisheries
-Protection of wilderness and unique
features
-Protection of existing and identified
potential features
-Consideration of legal restriction to
I and use
-Identification of areas where the
greatest change would occur
TABLE E.10.4:SENSITIVITY SCALING
Scale Rating Definition
A.E){;LUS ION
B.H IG-l SEr~s IT I VITY
Co MODERATE SENS IT IVITY
D.LC1.'I SENS IT IVITY
The significance of one factor is great
enough to exclude a site from further
consideration.There is little or no
possibility for mitigation of extreme adverse
impacts,or development of the site is
legally prohibited.
1)The most sensitive components of the
environmental criteria would be disturbed
by development,or
2)There exists a high potential for future
confl ict which should be investigated in
a more detai led assessment.
Areas of concern were less important than
those in "B"above.
1)Areas of concerns are common for most or
many of the sites.
2)Concerns are less important than those of
"C"above.
3)The avai lable information alone is not
enough to indicate a greater
sign if icance.
("--
roo'
]]1 1 J )J ····1 ..~.1 1 1 ·~l 1
TABLE E.l0.5:SENSITIVITY SCALING OF EVALUATION CRITERIA
Evaluation Criteria SCALE
BigGame:
Agricultural Potential
Waterfowl,Raptors and
Endangered Species
Anadromous Fisheries
Wi Iderness Consideration
Cultural,Recreational and
Scientific Features
A
Exclusion
-major anadromous fish
corridor for three or
more spec i es
-more than 50,000
salmon passinf:j site
B
High
-seasonal concentration
-are key range areas
-calving areas
-upland or lowland
so i Is sui t ab Ie for
farminf:j
.-nest i ng areas for:
•Peregr i ne Fa Icon
•Canada Goose
•Trumputee Swan
-year-round habitat
for neritic seabirds
and raptors
-key migration area
-three or more species
present or spawning
-identified as a major
anadromous fish area
AJ I of the fo I low i ng
-good-to-h igh qual ity:
•scen ic area
•natural features
•primitive values
-selected for wilderness
cons iderat ion
-existing or proposed
historic landmark
-reserve proposed for
the Ecological Reserve
Sy.stem
C
Moderate
-big game present
-bear denning area
-marginal farming soils
-high-density waterfowl
area
-waterfowl migration
and hunti ng area
-waterfowl migration
route
-waterfow I nest i ng or
molt area
-less than three
species present or
spawn i ng
-identified as an impor-
tant fish area
Two of the following
-good -to-h i gh qua Ii ty:
•scen ic area
•natural features
•primitive value
-site in or close to an
area selected for
wilderness consideration
-Site affects one or
more of the fol lOWing:
•boating potential
•recreational potential
•historic feature
•histor Ie tra iI
•archaeological site
•ecological reserve
nomination
•cultural feature
D
Low
-habitat or distribu-
tion area for bear
-no identified agri-
cultural potential
-medium or low density
waterfow J areas
-waterfow I present
-not identi fi ed as
a spawning or
rearing area.
One or less of the
followi ng
good-to-high qual ity:
•scen Ie area
•natural features
•primitive val ue
-site near one of the
factors in B or C
A B C --------0
Exclusion High Moderate Low
SCALE
TABLE E.10.5 (Continued)
Evaluation Criteria
Restricted Land Use
Access
-Significant impact to:
•Existing national
park
Federal lands with-
drawn by National
Monument Proclamations
-Impact to:
•Nat ion a I wi I d life
range
State park
•State game refuge,
range,or wilderness
preservation area
-no e~isting roads,
ra i I roads or airports
-terrain rough and
access difficult
-increase access to
wi I derness area
-Increase:
•Nat ional forest
•Proposed wi I d and
seen ic river
•National resource
area
Forest land withdrawn
for mineral entry
-existing trai Is
-proposed roads or
-existing airports
-close to existing
roads
- In one of the
following:
•State land
Native land
•t-bne of A,B,C
-existing roads or
ra i I roads
-existing power lines
,-.)
TABLE E.l0.6:
Site
Big Game
Agr icultural
Potential
Waterfowl,Raptors.
Endangered Species
All i son Creek -BI ack and Gr i zzl y bear
present
-flbne identified -Year-round habitat for
ner i t ic seab i rd sand
raptors
-Peregrine fal con
nest i ng area
-Waterfowl present
Bradley Lake -BI ack and Gr i zzl y bear
present
-Moose present
-25 to 30 percent of
so i I marg inal I y sui t-
able for farm ing
-high quality forests
-Peregrine Falcon
nesting areas
Browne -Black and Grizzl y bear
present
-Moose present
-Caribou winter range
-More than 50 percent
marg inal I y sui tab Ie
for farming
-Low density of water-
fowl
Bruskasna -Black and Grizzly bear -flbne ·identified
present
-Moose present
-Caribou winter range
-low density of water-
fowl
-Nest i ng and mo It i ng
area
Cha kachamna -BI ack bear habitat
-Moose present
-Upland spruce,hard-
wood forest
-Waterfowl nesting and
mol ting area
Coffee -Black and Grizzly bear
present
-Moose present
-More than 50 percent of
upperland suitable for
ag r ic ui ture
-Good forests
-Key waterfowl hab itat
Cathedral BI uffs -Black and Grizzly bear
present
-Moose present
-Da I I sheep present
-Moose concentration area
-More than 50 percent of
land marginal for farming
-Upl and spruee-har'dwood
forest
-Low density of water-
fowl
-Nesting and molting
area
Hicks
'-
-Black and Grizzly bear
present
-Caribou present
-Moose Wintering area
-flbne identified -Waterfowl nesting and
mol tlng area
-Low density of waterfowl
-Nesting and rrolting area
-25 to 50 percent of
upl and ~i I sui tab Ie
for farming
-Up I and spr uc e-ha rd wood
...'".forest
-Black and Grizzly bear
present
-Moose.car ibou and
bison present
Johnson
Keetna -BI ack and Gr '.Lzi y bear
present
-Car ibou winter area
-'~oose fall/winter
concentration area
-flbne identified -flbne identified,
Kenai Lake ""BI ack and Gr i zzl y bear
present
-Dall sheep habitat
-Moose fa II/wi nter
concentration area
-flbne identified
-Coastal hem I ock-
sitka spruce forest
-Waterfowl nesting and
rrol t I ng area
-
SITE EVALUATIONS
Evaluation Criteria
Anadromous
Fisheries
-Spawn i ng area for two
sa I mon spec i es
-t-bne identified
-t-bne
-t-bne
-Two species present
-Four spec i es present,
two spawn I ng in area
-One species present
-Far downstream from
site only
-Salmon spawning area,
one species present
-Four spec i es present,
one species spawning
near site
-Four species present,
two spa wn i ng
Wi I derness
."Cons I derat10n
-High-to-good-qual ity
scen Ic area
-G:>od-to-high-qual jty
scenery
-t-bne
-G:>od-to-h Igh-qual ity
scenery
-Area under wi I derness
cons Ideration
-G:>od-to-h igh-qual ity
scenery
-Primitive and natural
features
-None identified
-Q)od scenery
-t-bne Identified
-
-t-bne identified
-G:>od-to-h igh-qual ity
IT im it i.ve lands
-High-qual ity scenery
-Natural features
Cultural,Recreational,
and Scientific Features
-t'bne identi fi ed
-Boat j ng area
-Boat I ng potent i aI
-Boat i ng potenti al
-Proposed aco I o::l ica I
reserve site
-Boat i ng areas
-Boat i ng area
-t'bne identified
-t-bne i dent i fi ad
-Boat i ng potent i aI
-High boat I ng potent I al
-Boat I ng potent i al
Restr icted
Land Use
-Near Ch ugach
Nat ional Forest
-t-bne identi fi ed
-t-bne identi fl ed
-t-bne identi fi ed
-t-bne identi fi ed
-None Identified
-t-bne I dent i f i ed
-No present
restr lct ions
None Jdentl fi ed
-t-bne I den'ti f i ed
-Chugach N:lt lonal
Forest
TABLE E.10.6 (Continued)
Site
Big Game
Agricultural
Potential
Waterfowl.Rapters.
Endangered Species
KI utlna
Lane
Lowe
Lower Chul itna
Silver Lake
Skwentna
Snow
- B lack and Gr i zz I y bear
present
-Car Ibou present
-Moose fall concentra-
tion area
- B lack bear present
-Moose present
-Car Ibou present
-Black and Grizzly bear
present
-Moo se pre sen t
-BI ack and Gr i zzl y bear
present
-Car ibou present
-Black and Grizzly bear
present
-High density of seals
- B lack and Gr I zz I y bear
present
-Moose wi nter concentra-
tion area
-Black bear present
-Da I I sheep hab i tats
-Moose wInter concentra-
tion area
-25 to 50 percent of
soils marginal for
farm ing
-CI imate marg Inal for
farm ing upl and spruce-
hardwood forest
-More than 50 percent
of the soils in upper-
lands suitable for
fanni ng
-Bottomland spruce-
poplar forest
-Nbne identified
-Coastal western hem I ock-
sitka spruce forest
-More than 50 percent of
the upl and so i I s sui t-
able for fanning
-None identified
-Coasta r western hem I ock-
sitka spruce forest
-50 percent of upper I and s
suitable for fanning
-Lowl and spruce -
hardwood forest
-None identified
-Low-dens I ty waterfowl
,area
-Nesting and molting
area
-Low-density waterfowl
area
-Nesting and mol ting
area
-Peregrine Falcon
nesting area
-Medium-density waterfowl
area
-Nesting and molting
area
-Year-round habitat for
neritic seab irds and
raptors
-Low-dens I ty waterfOWl
area
-Nesting and molting
area
-Nesting and molting
area
Strandllne Lake -Moose,black bear
habitat
-Grizzly bear present
-25 to 50 percent margi--Nesting and molting
nal farm Ing so I I s area
- A Iplne tundra
Tal keetna 2-.
Cache
-Black and Grizzly bear -None identified
presnt
-Moose fal I/wlnter con-
centrat Ion area
-Caribou winter range
-Black and GriZZly beac~-None identified
present
-Moose-winter concen-
tration area
-Caribou winter range
-None Identified
-None Identi fled
Tazllna
ToklchLtna
-BI ack and Gr i zzl y bear
present
-Moose winter range
-Caribou winter range
-Bl ack bear present
-Moose pr ese nt
-Car i bou present
-None Identified
-Lowl and spruce-hardwood
forest
-More than 50 percent of
so i 1s are usab Ie for
farming (In upper lands)
-Med i urn-dens j ty water-
fowl area
-Nesting and molting.
area
-Medium-density water-
fowl area
-Nesting and molting area
r
Evaluation Criteria
An ad rcrno us
Fisheries
-Two spec ies present,
one species spawn in
vicinity of site
-Five species present
and spawn ins i te
vic in ity
-One species present,
others downstream of
site
-Four species present,
three spawn i ng in
v ic in Ity
-One spec les present,
more downstream
-Three species present,
spawn I ng in area
-f'bne
-t-bne present
-Four sp!?c i es present,
one species spawns at
site
-Fooc.species of salrlOn
present,spawning areas
ident i fl ed
-Two spec i es present
at site and upstream
-Four spec i es present,
three species spawn In
site vicinity
Wi I derness
Cons i derat I on
-High-qual ity scenery
-Natural fonnat ions
-Pr imitlve lands
-Sel ecta::!for wi I der-
ness consideration
-None identified
-C?ood-to-h igh-qual ity
scenery
-Area sel ected for
wilderness consideration
-Area sel ected for
wilderness consideration
-C?ood-to-h igh-qual Ity
scenery
-Primitive value
-None Identified
-t-bne identi fi ed
-C?ood-to-h igh-qual ity
scenery
-Primitive lands
-::....Good-to-high-qual ity
scenery
-Primitive lands
-Good-to-h i9h -q ua I i ty
scenery
-Primitive lands
-t-bne Identified
-BoN1er primitive area
Cultural,ReCreational,
and Scientific Features
-Boating p::>tentlal
-Boating opportun itles
identl fi ed
-Hi s tor ical feature
-Proposed ecol cg ic al
reserve site
-Boat i ng potent I aI
-Boat i ng area potent I al
-Boat I ng area
-Hi stor Ical tra II s
-Proposed ecological
reserves i te
-t-bne identi fi ad
-Boat Ing p::>tent I al
-Boat i ng pot-ent I aI
-Boat i ng.potent I aI
-Boat I ng potent i aI
Restr icted
Land Use
-None Identi fed
-None Identified
-Located near the
border of Chugach
Nat ional Forest
-f'bne Identified
-Chugach Nat ional
Fores
-None identified
-Located in Chugach
Nat ional Forest
-t-bne identi fied
-None identified
-t-bne identi fi ed
-t-bne i denti f i ed
-t-bne identified
TABLE f.1~6 (Continued)
Site
Big Game
Agricul fural
Potential
Waferfowl,Rilpfers,
Endangered Species
Tustumera
Upper Bel uga
Upper Nell i e
Juan
Whiskers
Yentna
-
- B lack bear hab i tat
-Dall sheep habitat
-Moose present
-Grizzly bear present
-Moose present
-Black bear habitat
-BI ack and Gr i zzl y bear
present
-Moose present
-Caribou present
-Black and Grizzly bear
present -
-Moose,spr i ngisurTlller/
winter concentration
-None Identified
-More than 50 percent of
upperlands are suitable
for farm ing
-lowland spruce-hardwood
forest
-None identified
-Coastal western hem I ock-
sitka spurce forest
-50 percent of upperlands
suitable for farming
-Bottom I and spruce-
poplar forest
-25 to 50 percent of
soils in lowlands are
suitable for farming
-Bottomland spruce-poplar
forest
-None identified
-Medium density water-
fowl area
-Nesting and molting
area
-None identi fi ed
-Low -dens I ty water fow I
area
-Nesting and molting
area
-Med i urn-dens I ty water-
fowl area
-Nesting and molting
area
Eva I uat Ion Cr iter i a
Anadranous
Fisheries
-None identified
-Four species present.
two species spawn in
area
-!'bne identi fi ed
-Five species present.
two spawn in area
-Five speci as spawn in
area
...,,;.;,.,
Wilderness
Consideration
-Sel ected for wi I derness
consideration
-Good-to-high-q ua I ity
scenery
-Natural features
-Primitive lands
-None identified
-Sel ected for wi I derness
consideration .
-High primitive,scenic,
and natural features
-None i dent i f i ad
-!'bne identi fi ed
Cultural.Recreational.
and Scientific Features
-None identified
-Boat i ng area
-Boat i ng potent i aI
-Boat i ng potent i aI .
-Boat i ng potent i at
Restr icted
Land Use
-Located in Kenai
flbt ional Moose Range
-Site wi th ina
des i gnated N3t ion a r
Wi I derness area
-None identified
-Chugach N3t lonal
Forest
-N:me identi fi ed
-None identified
TABLE E.l0.7:SITE EVALUATION MATRIX
Waterfowl,
Big Agricultural Raptors.Anadromous Wi I derness Cu It,Recrea,
Game Potential Endg.Species Fisheries Consideration &Scientific
Crescent La ke C 0 0 B C C
Chakachamna C 0 C C B C
Lower Bel uga C 0 C B 0 C
Coffee C B C B 0 C
\"pper Bel uga C B C B 0 C
Strand line Lake C C C 0 C 0
Bradley Lake C C B 0 C C
Kas i lof River C B C A 0 C
Tustumena C 0 0 0 B 0
Kenai lower C B C B C C
Kenai Lake B 0 C B C 0
Crescent Lake-2 C 0 C C C C
Grant Lake B 0 C B C C
Snow B 0 C 0 0 C
McClure Bay 0 0 B C B 0--
Upper Nell ie Juan R C 0 0 0 B C
All ison Creek 0 0 B C 0 0....-,,,0;1:.',....,
Solomon Gulch 0 0 B C 0 0
Lowe C 0 B C C C
Si Iver lake 0 0 B C C C
Power 'Creek 0 0 B A C C
Mil I i on Do I I ar 0 0 B A B C
Instal led Land
Restr icted Capaci ty Dam Flooded
Land Use Access (MW)Scheme Height (ft).(Acres)
A B Reservoir <150 <5000
w/Diversion
B C >100 R~servoir <150 <5000
w/Diversion
D D <25 Reservoir <150 <5000
and Dam
D D 25-100 Dam and <150 <5000
Reservoir
D D 25-100 Dam and 150-350 5000 to
Reservoir 100,000
D D <25 Reservoir <150 <5000
w/Di vers ion
D D 25-100 Reservo ir <150 <5000
w/Diversion
B D Reservoir 150-350 >100,000
w/Diversion
B B <25 Reservo ir <150 <5000
w/Diversion
B D 25-100 M Dam and <150 <5000
Reservoir
C D >100 Dam and >350 5000 to
Reservo ir 100,000
C D <25 Reservo i r <150 <5000
w/Di vers ion
C D <25 Reservoir <150 <5000
w/Diversion
C D 25-100 Reservo ir 150-350 5000 to
w/Diversion 100,000
C C <25 Reservo ir <150 <5000-w/Diversion
C <25 Reservo ir <150 <5000
w/Diversion
D D <25 Reservoir <150 <5000
"""'~.""-~w/Diversion
D D <25 Reservoir <150 <5000
w/Diversion
D D 25-100 Dam and 150-350 5000 to
Reservoir 100,000
C C <25-Reservo ir <150 <5000
w/Diversion
C C <25 Reservo ir <150 <5000
w/Diversion
C C Dam and <150 5000 to
Reservoir 100,000
TABLE E.10.7 (Continued)
Waterfowl,
Big Agricultural Raptors,Anadromous Wilderness Cult,Recrea,
Game Potential Endg.Species Fisheries Consideration &Scientific
Cleave C D B B B C
Wood Canyon C D C B B B
Tebay Lake C D D C B D
Hanagita C D D D B D
Klutina B C C C B C
Tazl ina B D C C D C
Gakona B C C C D C
Sanford B C C C D C
Gu i kana B D C C D B
Yentna B B C B D C
Talachultna B B C B D C
Skwentna B B C B D C
Lake Creek Upper C D C C C D
Lake Creek Lower C B C B D C
Lo~r Chul itna C B C B C C
Tokich itna C B C B C C
"'"q-Coal B D C C C C
~I":'-
01 io B D C C C C
Chu I itna B D C C C C
Wh i skers C B C B D C
Lane C B C B D C
Sheep Creek B D D D C C
I nstal led Land
Restr icted Capacity Dam Flooded
Land Use Access (MW)Scheme Height (ftl (Acres)
A D Dam and 150-350 5000 to
Reservo ir 100,000
A D Dam and >350 >100,000
Reservoir
A B Reservo ir <150 <5000
w/Diversion
A B Reservo ir <150 <5000
w/Diversion
D 25-100
C >100 Dam and 150-350 5000 to
Reservo ir 100,000
A D Dam and 150-350 5000 to
Reservoir 100,000
A D Dam and
Reservoi r
B D 25-100 Reservo ir 150-350 5000 to
w/Diversion 100,000
D C >100 Dam and <150 >100,000
Reservoir
D C 25-100 Dam and <150 5000 to
Reservo i r 100,000
D C 25-100 Dam and >350 5000 to
Reservoir 100,000
A C Reservoir <150 <5000
w/Diversion
D C Dam and 150-350 <5000
Reservoir
D D 25-100 Dam and 150-350 <5000--Reservo i r
D D >100 Dam and 150-350 5000 to
Reservoir 100,000
D D 25-100 Dam and 150-350 <5000
,,:;;...Reservo ir <>I.".'"
D D 25-100 Dam and ~150-350 <5000
Reservo i r
D D 25-100 Dam and 150-350 <5000
Reservoir
D C 25-100 Dam and <150 <5000
Reservoir
D C >100 Dam and 150-350 <5000
Reservoi r
D C 25-100 Dam and >350 <5000
Reservoir
TABLE E.l0.7 (Continued)
Waterfow I,
Big Agr icultural Raptors,Anadromous Wi I derness Cu It,Recrea,
Game Potential Endg.Species Fisheries Consideration &Sc i ent i fie
Keetna B D D B D C
Gran i te Gorge B D D B C C
Tal keetn,a-2 B D D B C C
Greenstone B 0 D B C C
Cache B D [)B C C
Hicks B D C D D D
Rampart C B B A D C
Vachon Island B B C A D C
Junction Island B B C A D C
Kantishna River C B C B D C
~kKi n ley Ri ver B D C D B C
Teklanika River B 0 D D B [)
Browne B C D D D C
Healy B C D D B B
Carlo B D D 0 B C'-
Yanert-2 B D D D B C
Bruskasna B D C D D B
,r----1.-'.~<,.*'
Tanana B B C B D C
Gerstle B B C C D C
Johnson C B C C D C
Cathedral BI uffs B C C C D D
Installed Land
Restr icted Capacity Dam Flooded
Land Use Access (MW)Scheme Height (ft)(Acres)
D C 25-100 Dam and >350 5000 to
Reservoir 100,000
D C 25-100 Reservoir 150-350 <5000
w/Diversion
D C 25-100 Dam and >350 5000 to
Reservoi r 100,000
D C 25-100 Reservoir 150-350 <5000
wiD i vers ion
D C 25-100 Dam and 150-350 <5000
Reservo i r
D D 25-100 Dam and 150-350 <5000
Reservoi r
C >100 Dam and >350 >100,000
Reservoir
D C >100 Dam and <150 >100,000
Reservo i r
D C >100 Dam and 150-350 >100,000
Reservoir
D C 25-100 Dam and <150 >100,000
Reservoir
A Dam and 150-350 <5000
Reservoir
A B Dam and >350 5000 to
Reservoir 100,000
D D >100 Dam and 150-350 5000 to
Reservoir 100,000
A D Dam and 150-350 5000 to
Reservo i r 100,000
A D Dam and 150-350 <5000--Reservoir
A D Dam and 150-350 5000 to
Reservoir 100,000
D D 25-100 Dam and 150-350 5000 to
~:;;...Reservoir 100,{fifo
D 0 25-100 Dam and <150 5000 to
Reservoir 100,000
D C 25-100 Dam and <150 <5000
Reservoir
D D >100 Dam and <150 5000 to
Reservoir 100,000
D D >100 Dam and 150-350 5000 to
Reservoir 100,000
-
~.,
,-
TABLE E.l0.B:CRITERIA WEIGHT ADJUSTMENTS
I\Cl.i USTe<WelqnTs
uam Helqt T KE servo I\re,
In it ial
Weiqht ++++++++++++
Big Game B 6 7 B
Agricultural
Potenti al 7 5 6 7
Bi rds B 6 7 B
Fisheries 10 B 9 10
TABLE E.l0.9:SITE CAPACITY GROUPS
......
-
Site Group
<25 MW
25-100 MW
>100 MW
No.of Sites
Evaluated
5
15
B
No.or :>ITes
Accepted
3
4 - 6
4
TABLE E.10.10:RANKING RESULTS
Site Group Partial Score Total Score
Sites:<25 MW
Strand line Lake 59 85
Nel I i~Juan Upper 37 96
Tustumena 37 106
A II ison Creek 65 82
Si Iver Lake 65 111
Sites:25 -100 MW
f"'.'-"
Hicks 62 79
Bruskasna 71 104
Brad I ey Lake 71 104
Snow 71 106
Cache 86 127
Lowe 89 122
Keetna 89 131
Ta I keetna - 2
98 134
Coffee 101 126
Wh iskers 101 134
KI ut ina 101 142
Lower Chu I it i ua 106 139
Bel uga Upper 117 142
Talachultna River 126 159
Skwentna 136 169
Sites>100 MW
Chakachamna 65 134
Browne 69 94
Tazl ina 89 124
Johnson 96 121
Cathedral BI uffs 101 126
Lane 106 139
Kenai Lake 112 147
Tokich itna 117 150
-
....
-
....
-!
-
TABLE E.l0.11:SHORTLISTED SITES
Environmental l,;apacity
Rating o -25 MW 25 -100 MW 100 MW
Good Strand line Lake*H icks*Browne*
A I I i son Creek*Snow*Johnson
Tustumena Cache*
Silver Lake Bruskasna*
Acceptable Keetna*Chakachamna*
Poor Ta I keetna-2*Lane
Lower Chu I itna Tokich itna
*10 selected sites
TABLE E.l0.12:ALTERNATIVE HYDRO DEVELOPMENT PLANS
I nstal led On-Li ne
Plan Description Capacity Date
A.l Cha kac hamna 500 1993
Keetna 100 1997
A.2 Chakachamna 500 1993
Keetna 100 1997
Snow 50 2002
A.3 Chakachamna 500 1993
Keetna 100 1996
Snow 50 1998
Strand Ii ne 20 1998
AI I i son Creek 8 1998
A.4 Chakachamna 500 1993
Keetna 100 1996
Snow 50 2002
Strand I ine 20 2002
All ison Creek 8 2002
A.5 Chakachamna 500 1993
Keetna 100 1996
Snow 50 2002
Tal keetna - 2 50 2002
Cache 50 2002
Strand line 20 2002
All ison Creek 8 2002
E-IO-198
--
.-
-
..-
-
-I
TABLE E.l0.13:OPERATING AND ECONOMIC PARAMETERS FOR SELECTED HYDROELECTRIC PLANTS
Max.Average Econom ic
Gross Installed Annua I Plant Capit'fl Cost of
Head Capac ity Energy Factor Cos€;Energy
No.Site River Ft.(MW)(Gwh)(%)($10 )($/1000 Kwh)
1 Snow Snow 690 50 220 50 255 45
2 Bruskasna Nena'na 235 30 140 53 238 113
3 Keetna Tal keetna 330 100 395 45 477 47
4 Cache Tal keetna 310 50 220 51 564 100
5 Browne Nenana 195 100 410 47 625 59
6 Tal keetna-2 Talkeetna 350 50 215 50 500 90
7 Hicks Matanuska 275 60 245 46 529 84
8 Chakachamna Chakachatna 945 500 1925 44 1480 30
9 AII ison AII i son Creek 1270 8 33 47 54 125
10 Strand line
Lake Bel uga 810 20 85 49 126 115
NOTES:
lllIlIncluding engineering and owner's administrative costs but excluding AFDC.
TABLE E.l0.14:SUSITNA DEVELOPMENT PLANS
Cumulative
Stage/Incremental Data System Data
Annua I
Maximum Energy
Capital Cost Earliest Reservoir Seasonal FToduct ion Plant
$Mil I ions On-line FUI I Supply Draw-Firm Avg.Factor
1
Plan Stage Construction (1980 va lues)Date Level -ft.down-ft GIti G\'i1-l.%
1.1 1 Watana 2225 ft 80Q.1W 1860 1993 2200 150 2670 3250 46
2 Dev i I Canyon 1470 ft
600 MW 1000 1996 1450 100 5500 6230 51
TOTA L SYST EM 1400 MW 2860
1.2 1 Watana 2060 ft 400 MW 1570 1992 2000 100 1710 2110 60
2 Watana raise to
2225 ft 360 1995 2200 150 2670 2990 85
3 Watana add 400 MW
2
capacity 130 1995 2200 150 2670 3250 46
4 Devi I Canyon 1470 ft
600 MW 1000 1996 1450 100 5500 6230 51
TOTAL SYSTEM 1400 MW 3060
1.3 1 Watana 2225 ft 400 MW 1740 1993 2200 150 2670 2990 85
2 Watana add 400 MW
capacity 150 1993 2200 150 2670 3250 46
3 Dev i I Canyon 1470 ft
600 MW 1000 1996 1450 100 5500 6230 51
TOTAL SYSTEM 1400 MW 2890
1 "9
J
)-1 1 1 i 1 J 1 -1 1 1 J 1
TABLE E.10.14 (Continued)
Cumu lat ive
Stage/Incremental Data System Data
Annual
Maximum Energy
Capital Cost Earliest Reservoir Seasonal Product Ion Plant
$Mil I ions On-I ine Full Supply ~aw-Firm Avg.Factor
Stage Construction (1 980 va lues)1 %Plan Date Level -ft.down-ft.GIti Gw-J
2.1 1 High Devil Canyon
1715 ft 800 MW 1500 1994 3 .1750 150 2460 3400 49
2 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47
TOTAL SYSTEM 1200 MW 2560
2.2 1 High Dev I I Canyon
31630ft400MW11401993 1610 100 1710 2020 58
2 High Dev i I Canyon
add 400 MW Capac Ity
raise dam to 1715 ft 500 1996 1750 150 2460 3400 49
3 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47
TOTAL SYSTe.1 1200 MW 2700
2.3 1 High Dev II Canyon
·1994 3
1715 ft 400 MW 1390 1750 150 2400 2760 79
2 High Dev II Canyon
add 400 MW capac ity 140 1994 1750 150 2460 3400 49
3 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47
TOTAL SYSTEM 1200 MW 2590
3.1 1 Watana 2225 ft 800 MW 1860 1993 2200 150 2670 3250 46
2 Watana ad d 50 MW
tunnel 330 MW 1500 1995 1475 4 4890 5430 53
TOTAL SYSTe.1 1180MW 3360
TABLE E.10.14 Continued)
Cumulative
Stage/Incremental Data System Data
Annua I
Maximum Energy
Capital Cost Earliest Reservoir Seasonal Product ion Plant
$Mill ions On-I ine Full Suppl y Draw-Firm Avg.Factor
Plan Stage Construction (1 980 va lues)1 'f,Date Level -ft.down-ft.GI'.H GI'.H
3.2 1 Watana 2225 ft 400 MW 1740 1993 2200 150 2670 2990 85
2 Watana add 400 MW
capac Ity 150 1994 2200 150 26703250 46
3 Tunnel 330 MW add
50 MW to Watana 1500 1995 1475 4 4890 5430 53
3390
4.1 1 Watana
,3
2225 ft 400 MW 1740 1995 2200 150 2670 2990 85
2 Watana add 400 MW
capac Ity 150 1996 2200 150 2670 3250 46
3 High Devil Canyon
1470 ft 400 MW 860 1998 1450 100 4520 5280 50
4 Portage Creek
1030 ft 150 MW 650 2000 1020 50 5110 6000 51
TOTAL SYSTEM 1350 MW 3400
NOTES:
(1)Allowing for a 3 year overl ap construction period between major dams.
(2)Plan 1.2 Stage 3 is less expensive than Plan 1.3 Stage 2 due to lower mobil ization costs.
(3)Assumes FERC I icense can be f i I ad by June 1984,i e.2 years I ater than for the Watana/Dev i 1 Canyon PI an 1.
"","l 1\
J J
}1 -1 I ')J )])1 ]J
TABLE E.l0.15:RESULTS OF SCREENING MODEL
TABLE E.1O.16:ENVIRONMENTAL EVALUATION OF DEVIL CANYON DAM ANI
Environmental
Attribute
Ecological:
-Downstream Fisheries
and Wi I d life
Resident Fisheries:
Wi Id life:
-Cu I tura I:
Land Use:
Concerns
Effects resulting
from changes in
water quantity and
qual ity.
Loss of resident
fisheries habitat.
Loss of wildl ife
habitat.
In undat ion of
archaeological
sites.
Inundation of Devil
Canyon.
Apprai sa I
(Differences in impact
of two schemes)
No significant difference
between schemes regarding
effects downstream from
Devil Canyon.
Difference in reach
between Devil Canyon
dam and tunnel re-
regulation dam.
Minimal differences
between schemes.
Minimal differences
between schemes.
Potential differences
between schemes.
Significant difference
between schemes.
I dent i f icat ion
of difference
With the tunnel scheme (
trolled flows between r«
tion dam and downstream
house offers potential·
anad romous fisher i es ent
rrent in this 11 mile re,
the river.
Devi I Canyon dam would i
27 mi les of the Susitna
and approximatel y 2 milE
Devi I Creek.The tunnel
would inundate 16 miles
Susitna River.
The most sensitive wildl
bitat in this reach is L
from the tunnel re-regul
dam where there is no si
cant difference between
schemes.The Dev i I .Can)
scheme in addition inunc
river valley between thE
damsites resulting in a
i ncrea se in impacts to ~
Due to the I arger area 1
dated,the probab iii ty (
undating archaeological
is i hcreased.
The Dev i I Canyon i s con~
a un iq ue resource,80 pE
of wh ich wou Id be i nundc
the Dev i I Ca nyon dam scl
This would result in a I
both an aesthetic valoo
the potent i al for wh ite
recreat ion.
OVERALL EVALUATION:The tunnel scheme has overal I a lower impact on the environment.
D TUNNEL SCHEME
Appraisal JUdgment
Not a factor in evaluation of
scheme.
Scheme jUdged to have
the least potential impact
,unnel DC
con-
egu la-
power-
for
hance-
ach of
inundate
River
es of
I scheme
of the
life 11a-
upstream
lation
ign i f i-
the
yon dam
dates the
e two
rroderate
wi I d life.
inun-
of in-
sites
5 idered
ercent
ated by
heme.
loss of
plus
water
If fisheries enhancement oppor-
tun i ty can be rea Ii zed the tun-
nel scheme offers a positive
mitigation measure not availctJle
with the Devil Canyon dam
scheme.Th is op portun i ty is
cons i dered ITPderate and favors
the tunn el scheme.However,
there are no current plans for
such enhancement and feasibil-
ity is uncertain.Potential
value is therefore not signi-
ficant relative to additional
cost of tunnel.
Loss of habi~at with dam scheme is
less than 5%of total for Susi tna
main stem.This reach of river is
therefore not considered to be
highly significant for resident
fisheries and thus the difference
between the schemes is minor and
favors the tunnel scheme.
Moderate wildl ife populations of
rroose,black bear,weasel,fox,
wolverine,other smal I mammals
a nd so ng birds a nd some r i par ian
cliff habitat for ravens and
raptors,in 11 mi les of river,
would be lost with the dam scheme.
Thus,the difference in loss of
wildl ife habitat is considered
moderate and favors the tunnel
scheme.-'Significant archeological
sites,if identified,can p-oba-
bly be excavated.Additional
costs coul d range from severa I
hundreds to hundreds of thousands
"of dollars,but are still consider-
ably less than the additional cost
of the tunnel scheme.This concern
is not considered a factor in scheme
evaluation.
The aesthetic and to some extent
the recreat ional losses aS9:>ci-
ated with the development of the
Devil Canyon dam is the main
aspect favoring the tunnel scheme.
However,current recreational uses
of Devil Canyon are low due to
[i mi ted access.Recreat ion develop-
ment of the area is similar for
both schemes.
x
x
x
x
-1 -1 )1 1 1 1 1 -1 )
TABLE E.l0.17:SOCIAL EVALUATION OF SUSITNA BASIN DEVELOPMENT SCHEMES/PLANS
AI I projects would have similar impacts on the state and
local economy.
Social
Aspect
Potential
non -renewab Ie
resource
displacement
Impact on
state economy
Impact on
local economy
Parameter
Mi I I ion tons
Beluga coal
over 50 yea rs
J
Tunnel
Scheme
80
Dev i I Canyon
Dam Scheme
110
High Devil Canyon/
Vee Plan
170
Watana/Dev i I
Canyon Plan
210
Remarks
Dev i I Canyon dam scheme
potential higher than
tunnel scheme.Watana/
Devil Canyon plan higher
than High Devil Canyon/
Vee plan.
Seismic
exposure
Risk of major
structural
failure
Potenti at
impact of
failure on
human life.
All projects designed to similar levels of safety.
Any dam fai lures would affect the same downstream
population.
Essentially no difference
between plans/schemes.
Overall
Eval uation
1.Devil Canyon dam superior to tunnel.
2.Watana/Devil Canyon superior to High Devil Canyon/Vee plan.
TABLE E.l0.18:OVERALL EVALUATION OF TUNNEL SCHEME AND DEVIL CANYON DAM SCHEME
ATTRIBUTE
Economic
Energy
Contribution
Environmental
Social
Overall
Eval uation
SUPER I OR PLAN
Dev i I Canyon Dam
Dev i I Canyon Dam
Tunnel
Devil Canyon Dam (Marginal)
Devil Canyon dam scheme is superior
Tradeoffs made:
Econom ic advantage of dam scheme
is jUdged to outweigh the reduced
env i ronmenta I impact assoc i ated
with the tunnel scheme.
TABLE E.l0.19:ENVIRONMENTAL EVALUATION OF WATANA/DEVIL CANYON AND HIG
Environmental Attribute Plan Comparison
EColorical:
1>i sheries
2)Wi Id life
a)r400se
b)Caribou
c)Furbearers
No significant difference in effects on downstream
anadromous fisheries.
HDC/V woul d inundate approximatel y 95 mi les of the
Susitna River and 28 miles of tributary streams,in-
cluding the Tyone River.
W/OC would inundate approximately 84 miles of the
Susitna River and 24 miles of tributary streams,
including Watana Creek•.
HDC/V would inundate 123 miles of critical winter
river-bottom habitat.
W/OC would inundate 108 miles of this river-bottom
hab itat.
HDC/V would inundate a large area upstream from Vee
util ized by three sUb-populations of moose that range
in the northeast section of the basin.
W/OC would inundate the Watana Creek area util ized by
moose.The condition of this sub-population of moose
and the qual ity of the habitat they are using appears
to be decreasing.
The increased length of river flooded,especially up-
stream from the Vee damsite,would result in the
HDC/V plan creating a greater potential division of
the Nelchina herd's range.In addition,an increase
in range would be directly inundated by the Vee res-
ervoir.
The area flooded by the Vee reservoir is considered
important to some key furbearers,particularly red fox.
This area is jUdged to be more important than the
Watana Creek area that would be inundated by the W/OC
plan.
Because of t
lesser inund
hab itat,and
ef fects on a
is jUdged to
Because of t
impact on mo
Sus itna,the
Because of t
on the Nelch
is cons i derel
Because of t
f urbearers t
d)Birds and Bears-Forest habitat,important for birds and black bears,The HDC/V pi
exists along the val ley slopes.The loss of this habi-
tat would be greater with the ~/DC plan.
Cultural:There is a high potential for discovery of archaeolog-
ical sites in the eaterly region of the Upper Susitna
Basin.The HDC/V plan has a greater potential of
affecting th~se sites.For other reaches of the river
the difference between plans is considered minimal.
The W/OC pial
tential effel
,H DEVIL CANYON/VEE DEVELOPMENT PLANS
Appraisal JUdgment
rhe avoidance of the Tyone River,
jat ion of res i dent f i s her i es
I no significant difference in the
madromous fisheries,the W/OC plan
)have less impact.
-he lower potent i aI for direct
lose populations within the
~W/DC plan is judged superior.
"he potential for a greater impact
ina car ibou herd,the HDC/V scheme
,d infer ior.
'he lesster potential for impact on
he W/OC is jUdged to be superior.
an is judged superior.-
n is judged to have a lower po-
et on arc~aeological sites.
Plan jUdged to have the
least potential impact
HDC/V W/DC
x
x
x
x
x
x
TABLE E.10.19 (Cont i nued)
Environmental Attribute
Aestheticj
Land Use
PIan Compar i son
With either scheme,the aesthetic qual ity of both
Devil Canyon and Vee Canyon would be impaired.The
HCCjV plan would also inundate Tsusena Fal Is.
Because of construction at Vee Dam site and the size
of the Vee Reservoir,the HDCjV plan would inherently
create access to more wilderness area than would the
WjDC plan.
Both plans ill
d i f ference is
As it is easi
I imit it,inh
cons idered de
jUdged su per i
of the area a
forces th i 5 j
OVERALL EVALUATION:The WjDC plan is judged to be superior to the HDCjV plan.
(The lower impact on birds and bears associated with HDCjV plan is considered 10
the other impacts which favour the WjDC plan.)
Notes:
W =Watana Dam
DC =Dev i I Canyon Dam
HCC =High Devil Canyon Dam
V =Vee Dam
--
Plan jUdged to have the
least potential impact
Appraisal JUdgment RDC/V w/OC
npact the valley aesthetics.The
;considered minimal.
ier to extend access than to
lerent access req uirerrents were
~trimental and the WIDe plan is
ior.The ecological sensitivity
)pened by the HOC/V p I an re i n-
j udgrrent.
)be outwe i ghed by al I
-
x
--
.-
I
TABLE E.l0.20:OVERALL EVALUATION OF THE HIG-l DEVIL CANYON/VEE
AND WATANA/DEVIL CANYON DAM PLANS
AllRIBD1E SUPERIoR PLAN
Economic Watana/Devil Canyon
Energy
Contribution Watana/Devil Canyon
Environmental Watana/Devil Canyon
Social WatanajDevil Canyon (Marginal)
-
.-
.....
Overal I •
Eval uation Plan with WatanajDevil Canyon is
super ior
Tradeoffs made:None
TABLE E.I0.21:ENVIRONMENTAL CONSTRAINTS -SOUTHf
Corridor
1
(ABC I )
2
(ADFC)
3
r~(AEFC)
Length
(Miles) Topography/Soils
73 Some soils with
severe 1 imitations
to off road travel;
some good agricul-
tural soils
38 Most of route
potent i ally wet,
with severe
limitations to
off road travel;
some good agri-
cultural soil s
39 Same as
Corridor 2
Land Use
No existing ROW in
AS;residential uses
near Palmer;proposed
capital site;muchu.s.Military Wdl.,
Private,and Village
Selection Land
Trail is only exist-
ing ROW;residential
and recreational
areas;Susitna Flats
Game Refuge;agri-
cultural land sale
No known existing
ROW;residential and
recreational use
areas,including
Nancy Lakes;lakes
used by float planes;
agricultural land
sale
Aesthetics
Id itarod Trai 1;
trail parelleling
Deception Ck.:
Gooding L.bird-
watching area;5
crossings of Glenn
Hwy.,1 crossing
of Parks Hwy.
Susitna Fl ats
Game Refuge;
Iditarod Trail;
1 crossing of
Pa rks Hwy.
Lake area south
of Willow;
Iditarod Trail;
1 crossing of
Pa rks Hwy.
Cultural Re~
Archeologic
data void
Archeologic
data void
Archeologic
data void
a Coastal area probably has many sites;available literature not yet reviewed.
b A
C
F
recommended
acceptabl elrut not recommended
=unacceptable
:RN STUDY AREA (WILLOW TO ANCHORAGE/POINT MACKENZIE
En vi ronmenta 1
;ources a Vegetation Fish Resources Wildlife Resources Rating b
s ites-Wetlands along 5 river and 28 creek Passes through or near C
Deception Ck.and crossings;valuable waterfowl and shorebird
at Matanuska River spawning sites,espe-nesting and feeding areas,
crossing;extensive ci ally ~a1mo n:and areas used by brown
clearing in upland,Knik area bear
forested areas Matanuska area
needed data void
sites-Extensive wetlands;1 river and 8 creek Passes through or near A
clearing needed in crossings;valuable waterfowl and shorebi rd
forested areas spawning sites,espe-nesting,feeding,and
cially salmon:migration areas,and
L.Susitna Ri ver areas used by furbearers
data void and brown bear
sites-Extensive wetlands;1 river and 8 creek Same as Corridor 2 F
clearing needed in crossings;valuable
forested areas spawning sites,espe-
cially salmon:
L.Susitna R.
data void
--
TABLE E.10.22:ENVIRONMENTAL CONSTRAII
Length
Corridor (Mil es)Topography/Soils Land Use Aesthetics Cul tural Re5
1
(ABeD)40 Crosses several Little existing ROW Fog Lakes;Archeologic
deep ravines;except Corps rd.;Stephan Lake;nea r Watana
about 1000 1 mostly Vill age proposed access
change in eleva-Selection and Pri-road
tion;some wet vate Lands
soils
2 45 Crosses several Little existing ROW Fog La kes;Same as Carr
(AVECD)deep ravines;except Corps rd.and Stephan Lake;pro-
about 2000'at D;rec.and reside posed acces road;
change in eleva-areas;float plane high country
tion;some steep areas;mostly Village (Prairie &Chulitna
slopes;some wet Selection and Private Creek drainages)
soil s Lands and viewshed of
-Al ask a Range
3 4·1 Crosses several No existing ROW except Viewshed of Alaska Archeologic
(AJCF)deep ravines;at F;rec.areas;Range and High Watana damsi
about 2000'float plane areas;Lake;proposed ac-near Portage
change in eleva-mostly Village Selec-cess road Susitna Rive
tion;some steep tion and Private Land;ence;possib
slopes;some wet reside and rec.devel-along Susitn
soil s opment in area of Otter Hi stori c sit
L.and old sled rd.commun it i es
Creek and Ca
4
(ABCJHI)77 Crosses several
deep ravines;
about >2000·
--change in eleva-
tion;routing
above 4000 1
;
steep slopes;
some wet soils;
shallow bedrock_
"in mountains
No existing ROW;
recreation areas and
isolated cabins;
lakes used by float
planes;much Village
Se 1ect i on Land
Fog La kes;
Stephan Lake;
proposed access
,road;vi ewshed of
Al aska Range
Archeologic
near Watana
Stephan Ll an
Fog Lakes;p
sites along
tween dra"ina
voi d between
.a A =recommended
C =acceptable but not recommended
F =unacceptable
NTS -CENTRAL STUDY AREA (DAMSITES TO INTERTIE)
sources a Vegetation Fish Resources Wildlife Resources _
En vi ronmenta 1
Rating b
sites Wetlands in eastern 1 river and 17 creek Unidentified raptor nest A
dams ite,third of corridor;crossings;valuable located on tributary to
extensive forest-spawning areas,Sus itna;passes through,
clearing needed especially grayling:habitat for:raptors,
data void furbearers,wolves,wol-
verine,brown bear,caribou
ridor 1 Wetlands in eastern 1 river and 17·eek Passes through habitat for:F
half of corridor;crossings;valuable raptors,waterfowl,migrat-
extensive forest-spawning areas,espe-ing swans,furbearers,cari-
cl eari ng needed'cially grayling:bou,wolves,wolverine,
data void brown bear
sites by
ite,and
e Creek/
~r confl u-
ble sites
la River;
tes near
of Gold
3nyon
sites
damsite,
1e and
)ossible-
pass be-
3ges;data
,Hand I
Fo rest-c 1eri ng
needed in western
half
Small wetland areas
in JA area;exten-
sive forest-clearing
needed;data-Void
14 creek crossings;
valuable spawning
areas,especially
grayling and salmon:
Indi an Ri ver
Portage Creek
Data Voi d
1 river and 42 creek
crossings;valuable
spawning areas,
especially grayling:
Golden eagle nest along
Devil Creek near High Lake;
active raven nest on Devil
Creek;passes through habi-
tat for:raptors,furbear-
ers,wolves,brown bear
Golden eagle nest along
Devil Creek near High Lake;
caribou movement area;
passes through habitat for:
raptors,waterfowl,fur-
bearers,wolves,wolverine,
brown bear
C
F
TABLE E.I0.22:(PAGE 2)
Length
Corridor (Miles)Topography/Soils Land Use Aesthetics Cultural Res
5 82 Crosses several Same as Corri dor 4 Fog Lakes;Same as Corr
(ABECJHI)deep ravines;Stephan Lake;
changes in eleva-High Lake;pro-
tion >2000';posed access road;
routing above viewshed at Alaska
4000 I;steep Range
slopes;some wet
s 0 i 1s;s hallow
bedrock in moun-
tains
6 68 Crosses several No known existing ROW;Fog La kes and Archeologie
(CVAH I)deep ravines;recreation areas and Stephan Lake;pro-nea r Watana I
changes in eleva-isolated cabins,float posed access road;Fog Lakes m
tion of about plane area;Susitna Tsusena Butte;Lake;data VI
1600 I ;routing area and near I are viewshed of between H an
above 4000 1
;Village and Selection Al aska Range
steep slopes;Land
some wet soils;
shall ow bedrock
in mountains
7
(CEBAHI)73 Crosses several Same as Corridor 6 Fog La kes;and Same as Corr
deep ravines;Stephan Lake;
changes in eleva-proposed access
tion of about road;high country
1600 1
;routing (Prairie-Chunilna
above 3000 1
;Creeks);Tsusena
steep slopes;Butte;viewshed of
some wet soils;Al aska Range
--shallow bedrock
in mountains
8 90 Crosses several No existing ROW;Fog Lakes;Archeologie
~,-~.(CBAG)deep ravines;recreatiGG areas and Stephan Lake;nea r Watana I
change in eleva-:.....isolated cabins,float access road;Fog Lakes,S
tion of about plane areas;air strip sceni e-area of Lake and alo
1600 I ;routing and airport;much Deadman Creek;man Creek
above 3000 1
;Village Selection and viewshed of
steep slopes;Federal Land Alaska Range
some wet soj 1 s;
shallow bedrock
in.;.mountai ns
a;ources
'idor 4
Vegetation
Wetlands in JA and
Stephan Lake areas;
extensive forest-
clearing needed
Fish Resources
42 creek crossings;
valuable spawning
a~eas,especially
grayling and salmon:
data void
Envi ronmenta 1
Wildlife Resources Rating b
Same as Corridor 4 with F
important waterfowl and
migrting swan habitat at
Stephan La ke
sites
dams ite,
ld Stephan
'oi d
ld I
'idor 6
Extensive wetlands
from B to near
Tsusena Butte;ex-
tensive forest-
clearing needed
Extensive wetlands
in Stephan Lake,
Fog Lakes,Tsusena
Butte areas;exten-
sive forest-
clearing needed
--
32 creek crossings;
valuable spawning
areas,especially
grayl ing:
data void
45 creek crossings;
valuable spawning
areas,especially
grayling:
data void
Bald eagle nest southeast
of Tsusena Butte;area of
caribou movement;passes
through habitat for:
raptors,waterfowl,fur-
bearers,wolves,wolverine,
brown bear
Same as Corridor 6 with
important waterfowl and
migrting swan habitat at
Stephan Lake
F
F
sites
damsJte,-
;tephan
mg Dead-
Wetlands between B
and mountains;ex-
tensive forest-
clearing needed
1 river and 43 creek Important bald eagle habi-
crossings;valuable ",..tat by Denali Hwy.and
spawni nq areas,espe-Deadman Lake;unchecked
cially grayling:bald eagle nest ne~Tsusena
data void Butte;passes through habi-
tat for:raptors,furbear-
ers,wolves,wolverine,
brown bear
F
TABLE E.10.22:(PAGE 3)
Corridor
9
(CEBAG)
10
(CJAG)
Length
(Miles)
95
68
Topography/Soils
Crosses several
deep ravines;
changes in eleva-
tion of about
1600 I;routing
above 3000 1
;
steep slopes;
some wet soil s;
shall ow bedrock
in mountains
Same as
Corri do r 8
Land Use
Same as Corridor 8
No existing ROW;
recreation areas and
isolated cabins,float
plane areas;air strip
and airport;mostly
Village Selection and
Federal Land
Aesthetics
Fog Lakes;
Stephan Lake;pro-
posed access road;
high country
(Prairie and
Chunilna Creeks);
Deadman Creek;
viewshed of Alaska
Range
High Lakes area;
proposed access
road;Deadman
Creek drainage;
viewshed of
Al aska Range
Cultural Re!
Same as Corr
Archeologic
near Watana
and along De
Creek
11 69 Crosses several
(CJAH1)deep ravines;
changes in eleva-
tion of 1000 1
;
routing above
3000 I,;steep
slopes;some wet
soils;shallow
bedrock in
mountains
12 70 --Same as
(JA-CJH 1)Corri do r 11
No existing ROW;
recreation areas and
isolated cabins;float
plane area;mostly
Village Selection and
Pri vate Land
No existing ROW;
recreation areas and
isolated cabins;float
plane area;mostly
Village Selection and
Pri vate -l"and
High Lakes area;
proposed access
road;viewshed
of Al ask a Range
High Lakes area;
,.proposed access
road;Tsusena
Butte;viewshed
of Al aska Range
Archeologic
Watana damsi
Archeologic
near Watana
possible si1
pass betweer
ages
13
(ABCF)
41 Crosses several
deep ravines;
about 1000 1
change in eleva-
tion;some'wet
soil s
No known existing ROW
except at F;recrea-
tion areas;float
plane areas;resident
and recreaction use
near Otter Lake and
Old Sled Road;iso-
lated cabins;mostly
Village Selection
Land and some Private
Land
Fog Lakes;
Stephan Lake;
proposed access
road
Archeologic
near Watana
Po rtage Crel
River confll
Stephan Lakl
Fog Lakes;I
sites;near
ties of Can:
Gold Creek
;ources a
'i do r 8
Vegetation
Wetlands in Stephan
Lake/Fog Lake areas;
extensive forest-
clearing needed
Fish Resources
1 river and 48 creek
crossings;valuable
spawning areas,espe-
cially grayling:
data void
Wildlife Resources
Same as Corridor 8 with
important waterfowl and
migrting swan habitat at
Stephan Lake
Environmental
Rating b
F
sites
damsite,
~adman
sites
ite
site
dams ite';-
tes along
n drai n-
sites
damsite;
ek/Susitn'a
uence,
e,and
historic
communi-
yon and
Small wetlands in JA
area;extensive
forest-clearing
needed
Small wetland areas
in JA area;some
forest-clearing
needed
Small wetland areas
in JA area;-rairly
extensive forest-
clearing needed
Wetlands in eastern
third of corridor;
extensive forest-
clearing needed
36 creek crossings;
valuable spawning
areas,especially
grayling and salmon:
data void
36 creek crossings;
valuable spawning
areas,especially
grayling and salmon:
Data voi d
40 creek crossings;
valuable spawning
areas;especially
grayling and salmon:
data void
15 creek crossings;
valuable spawning
areas,especially
grayling and salmon:
Indian Creek
Portage Creek
data void
Golden eagle nest along
Devil Creek near High Lake;
bald eagle nest southeast
of Tsusena Butte;passes
through habitat for:
raptors,furbearers,brown
bear
Golden eagle nest along
Devil Creek near High
Lake;bakd eagle nest
southeast of Tsusena Butte;
passes through habitat for:
raptors,furbearers,brown
bear
Golden eagle nest along
Devil Creek Qear High
Lake;pases through habi-
tat for:raptors,fur-
bearers,wolves,brown
.,¥bear
Unidentified rapto~nest
on tributary to Susitna;
passes through habitat
for:raptors,furbearers,
wolves,wolverine,brown
bear,caribou
F
F
F
A
TABLE E.10.22:(PAGE 4)
Corridor
14
(AJCD)
15
(ABECF)
,,"".•
Length
(Mil es)Topography /Soi 1 s -
41 Crosses deep
ravi ne at f)t:>vi 1
Creek;about
2000'change in
elevation;rout-
i ng above 3000';
some wet soils
45 Crosses several
deep ravines;
about 2000'
change in eleva-
tion
Land Use
Little existing ROW
except Old Corps Road
and at 0;recreation
areas;i sol ated
cabins;much Village
Selection Land;some
Pri vate Land
No known existing ROW
except at F;recrea-
tion areas;fJoat
plane areas;resident
and recreation use
near Old Sled Road;
isolated cabins;
mostly Village Selec-
tion Land with some
Pri vate Land
Aesthetics
Viewshed of
Alaska Range and
Hi gh Lake;pro-
posed access road
Fog Lakes;
Stephan Lake;
proposed access
road;high coun-
try (Prairie and
Chunilna Creeks
drainages);view-
shed of Al aska
Range
Cultural Re5
Archeologic
Watana dams i
possible sit
Susitna RivE
tori c sites
munities of
and Gol d ere
Same as Corr
sources a Vegetation Fish Resources Wildlife Resources
Environmental
Rating b
sites by
ite,
tes along
er;his-
near com-
Canyon
eek
ridor 13
--.,;,.,.<
Forest-clearing
needed in western
half
Wetlands in eastern
half of corridor;
extensve forest-
clearing needed
-
1 river and 16 creek
crossings;valuable
spawning areas,espe-
cially grayling:
data void
15 creek crossings;
valuable spawning
areas,especially
grayling and salmon:
Indi an Ri ver
Portage Creek
data void
Golden eagle nest in Devil C
Creek/High Lake area;
active raven nest on Devil
Creek;passes through habi-
tat for:raptors,furbear-
ers,brown bear,caribou
Important waterfowl and F
migrating swan habitat at
Stephan Lake;passes through
habitat for:raptors,water-
fowl,furbearers,wolves,
wolverine,brown bear,caribou
TABLE E.I0.23:ENVIRONMENTAL CONSTRAINTS -I
Corridor
1
(ABC)
Length
(Miles)Topography/Soils
90 Some wet soils
with severe
1 imitat ions to
off-road traffic
Land Use
Air strip;residential
areas and isolated
,cabins;some u.S.
Military Withdrawal
and Native Land
Aesthetics
3 crossings of
Parks Hwy.;
Nenana River
scemoc area
Cul tural Re!
Archeologic
probable sir
is a known ~
nearby;date
2 86 Severe limitations No known existing ROW 3 crossings of Dry Creek ar
(ABCD)to off-road traffic north of Browne;Parks Hwy.;site near He
on wet soils of scattered residential high visibility possible sit
the flats and isolated cabins;in open flats ri ver cross i
ai rstri p;Fort Wai n-data void
wright Military Reser-
vation
3 115 Change in eleva-No existing ROW beyond 1 crossing of Dry Creek ar
(ABEDC)tion of about Healy/Cody Creek con-Parks Hwy.;site near He
2500 I;steep fl uence;i~olated high visibil ity possible sit
slopes;shallow cabins;airstrips;in open flats Japan Hills
bedrock in moun-Fort Wainwright Mili-the mountair
tains;severe tary Reservat ion data void
1 imitat ions to
off-road traffic
in the flats
4
(AEF)
105 Same as Corridor 3
-
Air strips;isolated
cabins;Fort Wain-
wright Military Reser-
vation
High visibil ity
in open fl ats
Archeologic
near Dry ere
Fo rt Wa i nwri
possible sit
Tanana River
void
a Source:Vanballenberghe personal communication.Prime habitat =minimum amount
of land necessary to provide a substantial yield for a species;based
upon knowledge of that species·needs from experience of ADF&G personnel.
Important habitat =land which ADF&G considers not as critical to a species
as is Prime habitat,but is valuable.
b A
C =
F =
recommended
acceptable but not preferred
unacceptable
NORTHER STUDY AREA (HEALY TO FAIRBANKS)
sources a
sites
nce there
site
a void
Vegetation
Extensive wetlands;
forest-clearing
needed,mainly north
of the Tanana River
Fish Resources
4 river and 40 creek
crossings;valuable
spawning sites:
Tanana Ri ver
data void
Environmental
Wildlife Resources Rating b
Passes through or near A
prime habitat for:
peregrines,waterfowl
furbearers,moose;passes
through or near important
habitat for:peregri nes,
golden eagles
rcheologic
ealy;
tes along
ings;
rcheologic
eal y;
tes near
and in
ns;
sites
eek and
ight;
tes near
r;data ""C
Probably extensive
wetlands between
Wood and Tanana
Rivers;extensive
forest-clearing
needed north of
Tanana Ri ver
Probably extensive
wetlands between
Wood and Tanana
Rivers;extensive
forest-clearing
needed north of
Tanana River;data
lacking for south-
ern part
Probable extensive
wetlands between
Wood and Tanana
Ri vers -
5 river and 44 creek
crossings;valuable
spawnfng sites:
Wood River
data void
3 river and 72 creek
crossings;valuable
spawning sites:
Wood River
data void
3 river and 60 creek
crossings;valuable
spawning sites:
Wood River
data void
Passes through or near
prime habitat for:pere-
grines,waterfowl,furbear-
ers;passes through or near
important habitat for:,
golden eagles,other raptors
Passes through or near prime
habitat for:peregrines,
waterfowl,furbearers,cari-
bou,sheep;passes through
or near important habitat
for:golden eagles,brown
bear
Passes through or near
prime habitat for:
peregrines,bald eagles,
waterfowl,furbearers,cari-
bou,sheep;~asses through
habitat for:golden eagles,
hrown bear
c
F
F
-
TABLE E.l0.25:WATANA PRE-PROJECT MONTHLY FLOW (cfs)MODIFIED HYDROLOGY
YEAR UCT NOV nEC JAN FEB MAR APR MAY JUN JUL AUG SEP ANNUAL
1 4720.2084.1169.815.642.569.680.8656.16432.19193.16914.7320.6648.1.,3299.1107.906.808.673.620.1302.11650.18518.19787. 16478.17206.7733.7"-
3 4593.2170.1501.1275.841.735.804.4217.25773.22111.17356.11571.7776.7
4 6286.2757.1281.819.612.671.1382.15037.21470.17355.16682.11514.8035.2
5 4219.1600.1184.1088.803.638.943.11697.19477 •16984.20421.9166.7400.4
6 3859.2051.1550. 1388.1051.886.941.6718.24881.23788.23537.13448.8719.3
7 4102.1588.1039.817.755.694.718.12953.27172.25831.19153.13194.9051.0
8 4208.2277 •1707.1373.1189.935.945.10176.25275.19949.17318.14841.8381.0
9 6035.2936.2259.148"1.1042.974.1265.9958.22098.19753.18843.5979.7769.4
10 3668.1730.1115.1081.949.694.886.10141.18330.20493.23940.12467.8011.0
11 5166.2214.1672 •1400.1139.961.1070.13044.13233.19506.19323. 16086.7954.0
12 6049.2328.1973 •1780.1305.1331.1965.13638.22784.19840. 19480.10146.8602.9
13 4638.2263.1760 •1609.1257.1177 •1457.11334.36017.23444.19887.12746.9832.9
14 5560.2509.1709. 1309.1185.884.777.15299.20663.28767.21011.10800.9277.7
15 5187.1789.1195.852.782.575.609.3579.42842.20083.14048.7524.8262.7
16 4759.2368.1070.863.773.807.1232.10966 •21213.23236.17394.16226.8451.5
17 5221.1565.1204.1060.985.985.1338.7094.25940.16154.17391.9214.7374.4
18 3270.1202.1122. 1102.1031.890.850.12556.24712.21987. 26105.13673 •9095.7
19 4019.1934.1704. 1618.1560 •1560.1577 •12827.25704.22083.14148.7164.8032.2
20 3447.1567.1073.884.748.686.850.7942.17509.15871.14078.8150.6100.4
21 2403.1021.709.636.602.624.986.9536.14399.18410.16264.7224.6114.6
22 3768.2496.1687.1097.777.717.814.2857.27613.21126.27447.12189.8588.5
23 4979.2587.1957.1671.1491.1366 •1305.15973.27429.19820.17510.10956.8963.4
24 4301.1978. 1247. 1032.1000.874.914.7287.23859.16351.18017.8100.7112.0
25 3057.1355.932.786.690.627.872.12889.14781.15972.13524.9786.6313.7
26 3089.1474.1277 •1216.1110.1041.1211.11672.26689.23430.15127. 13075.8402.7
27 5679.1601.876.758.743.691.1060.8939.19994.17015.18394.5712.6834.8
28 2974.1927.1688.1349.1203.1111.1203.8569.31353.19707.16807.10613.8232.6
29 5794.2645.1980.1578.1268.1257. 1408.11232.17277 •18385.13412.7133.6992.2
30 3774.1945.1313.1137.1055.1101.1318.12369.22905.24912.16671.9097.8183.7
31 6150.3525.2032.1470.1233.1177 •1404.10140.23400.26740.18000. 11000.8907.9
32 6458.3297.1385.1147.971.889.1103.10406.17017.27840.31435.12026.9580.4
MAX 6458.3525.2259.1780.1560.1560 •1965.15973.42842.28767.31435.17206.9832.9
MIN 2403.1021.709.636. 602.569.609.2857.13233.15871.13412.5712.6100.4
MEAN 4523.2059.1415.1166 •983.898.1100.10355.23024.20810.18629. 10792.8023.0
l ~~l
t )1 1 J 1 1 -1 -)1 1 )1 )-]]
TABLE E.l0.26:DEVIL CANYON PRE-PROJECT MONTHLY FLOW (cfs)MODIFIED HYDROLOGY
YEAR OCT NOV I1EC JAN FEB MAR APR MAY JUN JUL AUG SEf'ANNUAL
1 5758.2405.1343.951.736. 670.802.10491.18469.21383.18821.7951.7537.8
2 3652.1231.1031.906.768.697.1505.13219.19979.21576.18530.19799.8615.9
3 5222.2539.1758.1484.943.828.879.4990~30014.24862.19647.13441.8918.0
4 7518.3233.1550.1000.746.767.1532.17758.25231.19184.19207.13928.9356.4
5 5109.1921.1387.1224.930.729.1131.15286.23188.19154.24072.11579.8866.9
6 4830.2507.1868.1649.1275.1024.1107.8390.28082.26213.24960.13989.9707.4
7 4648.1789.1207.922.893.852.867.15979.31137.29212.22610.16496.10608.2
8 5235.2774.1987.1583. 1389.1105.1109.12474.28415.22110.19389.18029.9668.7
9 7435.3590.2905.1792 •1212.1086.1437.11849.24414.21763.21220.6989.8866.8
10 4403.2000.1371.1317.1179.878.1120.13901.21538.23390.28594.15330.9649.6
11 6061.2623.2012.1686.1340.1113.1218.14803.14710.21739.22066.18930.9084.4
12 7171.2760.2437.2212.1594.1639.2405.16031.27069.22881.21164.12219.10021.3
13 5459.2544.1979.1796.1413.1320.1613.12141.40680.24991.22242.14767.10946.5
14 6308.2696.1896.1496.1387.958.811.17698.24094.32388.22721.11777.10431.8
15 5998.2085.1387.978.900.664.697.4047.47816.21926.15586.8840.9250.7
16 5744.2645.1161.925.829. 867.1314.12267.24110.26196.19789.18234.9555.5
17 6497.1908.1478.1279.1187.1187.1619.8734.30446.18536.20245.10844.8697.0
18 3844.1458. 1365.
1358.1268.1089.1054.14436.27796.25081.30293.15728.10460.4
19 4585.2204.1930.1851.1779.1779.1791.14982.29462.24871.16091.8226.9175.4
20 3976.1783.1237.1012.859.780.959.9154.19421.17291.15500.9188.6800.1
21 2867.1146.810.757.709.722.1047.10722.17119.21142.18653.8444.7063.9
22 4745.3082.2075.1319.944.867.986.3428.31031.22942.30316.13636.9657.2
23 5537.2912.2313.2036.1836.1660 •1566.19777.31930.21717.18654.11884.10199.0
24 4639.2155.1387.1140.1129.955.987.7896.26393.17572 •19478.8726.7738.3
25 3491.1463.997.843.746.690.949.15005.16767.17790.15257.11370.7160.5
26 3507.1619.1487.1409.1342.1272 •1457.14037.30303.26188.17032.15155.9606.6
27 7003.1853.1008.897.876.825.1261.11305.22814.18253.19298.6463.7705.5
28 3552.2392 •2148.1657.1470.1361.1510.11212.35607.21741.18371.11916.9438.8
29 6936.3211.2371.1868.1525.1481.1597.11693.18417.20079.15327.8080.7765.1
30 4502.2324.1549.1304.1204.1165.1403.13334.24052.27463.19107.10172.9023.0
31 6900.3955.2279.1649.1383.1321.1575.11377.26255.30002.20196.12342.9994.5
32 7246.3699.1554.1287.1089.997.1238.11676.17741.31236.35270.12762.10577.9
MAX 7518.3955.2905.2212.1836.1779.2405.19777 •47816.32388.35270.19799.10946.5
MIN 2867.1146.810.757.709.664.697.3428.14710.17291. 15257.
6463.6800.1
MEAN 5324.2391.1664.1362.1152.1042.1267.12190.26078.23152.20928.12414.9129.7
TABLE E.l0.27:GOLD CREEK PRE-PROJECT MONTHLY FLOW (cfs)MODIFIED HYDROLOGY
YEAR OCT NOV [IEC JAN FEB MAR APR MAY JUN JUL AUG SEP ANNUAL
1 6335.2583.1439.1027.788.726.870.11510.19600.22600.19880.8301.8032.1
"}3848.1300.1100.960 •820.740.1617.14090.20790.22570.19670.21240.9106.0...
3 5571.2744.1900.1600.1000.880.920.5419.32370.26390.20920.14480.9552.1
4 8202.3497.1700.1100.820.820.1615.19270.27320.20200.20610.15270.10090.4
5 5604.2100.1500.1300. 1000.780.1235.17280.25250.20360 •26100.12920.9681.6
6 5370.2760.2045.1794.1400. 1100.1200.9319.29860.27560. 25750.14290.10256.4
7 4951.1900.1300.980.970.940.950.17660 •33340.31090.24530.18330.11473.3
8 5806.3050.2142.1700.1500.1200.1200.13750.30160.23310. 20540.19800.10384.1
9 8212.3954.3264.1965. 1307.1148. 1533.12900.25700.22880.22540.7550.9476.4
10 4811.2150.1513.1448.1307.980.1250.15990.23320.25000.31180.16920.10559.9
11 6558.2850.2200.1845.1452.1197.1300.15780.15530.22980.23590.20510.9712.3
12 7794.3000.2694.2452.1754.1810.2650.17360.29450.24570.22100.13370.10809.3
13 5916.2700.2100.1900.1500.1400. 1700.12590.43270.25850.23550.15890.11565.2
14 6723.2800.2000.1600.1500.1000.830.19030.26000.34400.23670.12320.11072.9
15 6449.2250.1494.1048.966.713.745.4307.50580.22950.16440.9571.9799.6
16 6291.2799.1211.960.860.900.1360 •12990.25720.27840.21120.19350.10168.8
17 7205.2098.1631.1400. 1300.1300.1775.9645.32950.19860.21830.11750.9431.8
18 4163.1600.1500.1500. 1400.1200.1167.15480.29510.26800.32620.16870.11218.5
19 4900.2353. 2055.1981.1900.1900.1910.16180.31550.26420.17170.8816.9810.6
20 4272.1906.1330.1086.922.833.1022 •9852.20523.18093. 16322.9776.7200.1
21 3124.1215.866.824.768.776.1080.11380.18630.22660.19980.9121.7591.2
22 5288.3407.2290.1442.1036.950.1082.3745.32930.23950.31910.14440.10251.0
23 5847.3093.2510.2239.2028.1823.1710.21890.34430.22770.19290.12400.Itt885.5
24 4826.2253.1465.1200. 1200.1000. 1027.8235.27800.18250.20290.9074.8086.2
25 3733.1523. 1034.874.777.724.992.16180.17870.18800.16220. 12250.7631.0
26 3739.1700. 1603.1516.1471.1400.1593.15350.32310.27720.18090.16310.10275~4
27 7739.1993.1081.974.950.900.1373.12620.24380.18940.19800.6881.8189.3
28 3874.2650.2403.1829.1618.1500.1680.12680.37970.22870.19240.12640.10109.0
29 7571.3525.2589. 2029.1668.1605.1702.11950.19050.21020.16390.8607.8194.5
30 4907.2535.1681 •1397.1286.1200.1450.13870.24690.28880.20460.10770.9489.3
31 7311.4192.2416.1748.1466.1400.1670.12060.29080.32660.20960.13280.10747.7
32 7725.3986.1773.1454. 1236.1114.1368.13317.18143.32000.38538.13171.11255.3
MAX 8212.4192.3264.2452.2028.1900.2650.21890.50580.34400.38538.21240.11565.2
MIN 3124.1215.866.824.768.713.745.3745.15530.18093. 16220.6881.7200.1
MEAN 5771.2577 •1807.1474. 1249.1124.1362.13240.27815.24445. 22228.13321.9753.3
1 1
r-
12/16/82
TABLE E.l0.28:MINIMUM DOWNSTREAM FLOW REQUIREMENTS AT GOLD CREEK
Flow (cfs)
Month During Fi II rng Operation
r-Oct 2.000 5.000
Nov Natural 5.000
Dec Natural 5.000
Jan Natural 5.000
Feb Natural 5.000
Mar Natural 5.000
Apr Natural 5.000
May 5 680(1)6.000•
Jun 6.000 6.000-JuI 6 480(2)6 480(2)••
Aug 12.000 12.000
.-9.100(3)9 300(4)Sep •
Notes:
r-(1)May 1 2.000*(2 )Jul 1-26 6.000
2 3.000*27 7.000
3 4.000*28 8.000
~~4 5.000*29 9.000
5-31 6.000 30 10.000
31 11.000
(3)Sep 1-14 12.000 (4 )Sep 1-14 12.000
15 11.000 15 11.000
16 10.000 16 10.000
17 9.000 17 9.000
18 8.000 18 8.000
19 7.000 19 7.000
!"'"20-27 6.000 20-30 6.000
28 5.000
29 4.000
30 3.000
*Natura I flows up to 6000 cfs wi II be discharged when they are greater than
,.....stated flows.
TABLE E.l0.29:ALASKAN GAS FIELDS
Location/Field
North S lope:
Prudhoe Bay
East Umiat
Kavik
Kamik
South Barrow 2
Cook Inlet:
Tota I:
1
Remaining Reserves
Gas
(bi II ion cubic feet)
29,000
Unknown
Unknown
Unknown
25
29,025+
Product
Destination
or Field
Status
Pipeline construction to
Lower 48 underway
Shut-in
Shut-In
Shut-i n
Barrow res i dent i a 1 an d
commercial users
Albert Kaloa
Beaver Creek
Bel uga
Birch Hill
Fa II s Creek
Ivan River
Kenai
Lewis River
McArthur River
Moquawkie
Nicolai Creek
North Cook Inlet
North Fork
North Middle Ground Shoal
Ster ling
Swanson River
West Foreland
West Fork
Tota I:
Notes:
Unknown
250
767
20
80
5
1313
Unknown
78
None
17
1074
20
125
23
300
120
7
4189+
Shut-in
Local
Beluga River Power Plant (CEA)
Shut-in
Shut-In
Shut-In
LNG Plant,Anchorage and
Kenai users
Shut-I n
Local
Field Abandoned
Granite Pt.Field
LNG Plant
Shut-In
Shut-l n
Kena i users
Shut-i n
Shut-In
Shut-In
(1)Recoverable reserves estimated to show magnitude of field only.
(2)Produc i ng.
TABLE E.1D.3D:ALASKAN OIL FIELDS
.....
-
Locatron/F fe Id
North Slope:
Prudhoe Bay (b)
Simpson
Ugnu
Umiat
Cook Inlet:
Total:
(a)
Remaining Reserves
Gas
(million barrels)
8,375
Unknown
Unknown
Unknown
8,375+
Product
Destination
or Field
Status
Pipeline to Valdez
Shut-In
Shut-i n
Shut-In
Beaver Creek
Granite Point
McArthur River
Middle Ground Shoal
Redoubt Shoa I
Swanson River
Trading Bay
Total:
Notes:
D
21
118
36
None
22
4
198+
Refinery
Drift River Terminal
Drift River Terminal
Nikiski Terminal
Fie Id Abandoned
Nikiski Terminal
Nikiski Terminal
-
(a)Recoverable reserves estimated to show magnitude of field only.
(b)Producing.
TABLE E.l0.31:SULFUR DIOXIDE EMISSIONS FOR VARIOUS TECHNOLOGIES
Technology
Steam Electric
01 I (a)
Gas
Combustion Turbine
Oi I
Gas(b)
Emission Rate
(I b/10 6 Btu)
0.20
0.0006
0.30
Annual Emissions at 75%
Load Factor (Tons/Yr)
Facil ity Size (MWe)
20 50 200 400 600
131 329 1314 2628 3942
o 1 4 8 12
269 673
(a)New Source Performance Standard.
(b)Negligible.
-
TABLE E.l0.32:PARTICULATE MATTER EMISSIONS FOR VARIOUS TECHNOLOGIES
Technology
Steam Electric
Oil (a)
Gas(b)
Combustion Turbine
Oi I
Gas(c)
Emission Rate
(lb/l0 6 Btu)
0.03
0.01
0.05
Annual Emissions at 75%
Load Factor (Tons/Yr)
Faci I ity Size (MWe)
20 50 200 400 600
20 49 197 394 591
716 66 131 197
46 125
-
(a)New Source Performance Standard.
(b)Typical.
(c)Neg I i gib Ie.
TABLE E.l0.33:NITROGEN'OXIOES EMISSIONS FOR VARIOUS TECHNOLOGIES
Techno logy
Steam E I ectr ic
Oi I (a)
Gas (a)
Combustion Turbine
Oi I
Gas (b)
Emission Rate
(lb/10 6 Btu)
0.3
0.2
0.59
Annual Emissions at 75%
Load Factor (Tons/Yr)
Faci I ity Size (MWe)
20 50 200 400 600
197 493 1971 3942 5913
131 329 1314 2628 3942
530 1272
(a)New Source Performance Standard.
(b)Comparab Ie to 0 i I.
1 ,1 1 ,j I 1 1 J ))-'~]'1 '}1
TABLE E.IO.34 NATIONAL AMBIENT AIR QUALITY STANDARDS AND PREVENTION OF
SIGNIFICANT DETERIORATION INCREMENTS FOR SELECTED AIR POLLUTANTS
National Ambient Prevention of Significant
Air Qual ity Deterioration Increments
Standard ci ass I Class II
Pollutant 3_h(a)24-h (a)Annual 3-h 24-h Annua I 30-h 24-h Annua I
Tota I Suspended
Particula!e Matter None 150 (b)60(b)3 (c)None 37 19 None 10 5
(g/m )260 75
Sulfur Dioxide
(g/m3 )1300(b)365 (d)80 (d)512 91 20 25 5 2
Nitrogen Dioxide
3 None None 100(d)N/A N/A N/A N/A N/A N/A
(g/m )
Carbon Mo~oxide(e)
None N/A N/A N/A N/A N/A N/A(mg/m )
N/A -Not appl icable (no standards have been issued).
(a)Not to be exceed ed more than once per year.
(b)Secondary or wei fare-~otecti ng standard.
(c)Annual geometric mean,advisory indicator of compliance.
(d)Primary or health-protecting standard.
(e)Carbon monoxide primarY3ambient air quality standar~s are as foll~s.The value not to be exceeded more
than 1 hr/yr is 40 mg/m (~ay be changed to 29 mg/m ;the value not to be exceeded more than one 8-h
per iod per year is 10 mg/m •
River/Location
TABLE E.10.35:WATER QUALITY DATA FOR SELECTED ALASKAN RIVERS(al
Silica Iron Manganese Calcium Magnesium Sodium Potassium
Station No.Flow (cfsl (mg/Il (mg/Il (mg/Il (mg/Il (mg/Il (mg/Il (mg/Il
Copper River near Chitina
Matanuska River at Pa Imer
Susitna River at Gold Creek
Susltna River at Susitna Station
Chena River at Fairbanks
Tanana River at Nenana
Nenana River near Healy
Gul kana River at Sourdough
Talkeetna River near Talkeetna
Yukon River at Ruby
Chakachutna River near Tyonek
Skwentna River near Skwentna
Lowe River near Valdez
Fortymi Ie River near Steel Creek
15212000
15284000
15292000
15294350
15514000
15515000
15518000
15200280
15292700
15564800
15294500
15294300
15226500
6,100
159,000
11,600
566
34,000
1,960
6,790
148,000
10,200
182
4,740
34,300
497
8,750
286
6,130
1,930
19,800
345,000
26,900
6,640
15,100
6,760
1,330
390
1,100
14
8.5
4.5
6.3
5.7
11
10
3.6
6.4
23
19
7.4
8.2
4.0
7.3
5.1
6.2
12
5.3
5.3
11
13
5.0
2.0
11
0.02
0.07
0.19
0.09
0.07
2.7
3.2
0.55
0.19
0.39
0.03
0.94
0.04
0.08
0.02
0.13
0.85
0.75
0.82
0.02
0.02
0.01
0.05
0.02
36
23
28
44
12
34
26
17
12
36
54
24
36
18
19
8.1
27
46
9.1
14
17
28
28
22
20
9.3
3.5
1.8
4.8
1.4
4.5
4.2
2.3
2.3
7.6
10
5.0
10
3.6
2.2
1.0
6.1
10
2.1
1.8
5.0
4.3
0.8
1.0
7.5
12
4.3
3.8
8.9
3.1
11
7.1
1.8
1•1
4.9
4.8
2.7
5.6
2.7
8.3
2.6
2.2
3.9
1.4
1.5
4.4
7.7
1.2
1.4
4.6
1.6
2.0
0.9
0.9
1.3
2.4
1.5
1.5
2.1
2.8
2.9
1.9
2.6
1.4
1.0
0.5
1.9
2.0
1.5
1.7
0.9
1.7
2.7
2.5
1.2
(al Adapted from U.S.G.S.Water Data Report AK-77-1 and U.S.G.S.Open Fi Ie Report 76-513.
1 J ..-)--J J 1 )1 1 )])1
TABLE E.l0.35 (Cont'd)
Si I ica I ron Manganese Calcium Magnesium Sodium Potass
River lLocat i on Station No.Flow (cfs)(maL!.l (mg/I)(mg/I)(mg/I)(mg/I)(mg/I)(mg/i urn
I )
Copper River near Chitina 15212000 116 26 18 0.9 -- --
174 7.2
78 15 3.2 0 ----98 7.6
Matanuska River at Palmer 15284000 61 29 2.5 0.2 ----94 7.0
100 41 13 0.25 ---169 8.1
Susitna River at Gold Creek 15292000 36 6.0 4.0 0.14 ----52 6.8
98 12 29 0.11 ----152 8.0
Susitna River at Susitna Station 15294350 82 15 13 0.24 0.0 --116 6.9
59 13 2.2 0.05 1.1 11.3 64 8.1
Chena River at Fairbanks 15514000 30 10 0.7 0.27 ----54 7.0
140 13 2.1 0.52 ----165 6.6
Tanana River at Nenana 15515000 173 33 2.4 0.30 ----212 7.5
72 34 2.5 0.10 ---113 7.2
Nenana River near Healy 15518000 102 51 5.0 0.11 ----169 7.0
57 14 1.1 0.09 ---74 7.0
Gu I kana River at Sourdough 15200280 110 ----0.15 0.03 10.1 --7.5
40 ----0.04 0.15 11.0 --7.1
Talkeetna River near Talkeetna 15292700 52 10 12 --0.00 14.1 91 7.7
28 2.8 2.6 0.20 0.08 11.7 37 6.8
Yukon River at Ruby 15564800 94 1.4 0.2 0.04 ----113 7.6
165 25 1.3 0.23 ----183
Chakachutna River near Tyonek 15294500 26 12 2.0 0.00 ----46 7.1
26 11 1.4 0.03 ----51 7.5
Skwentna River near Skwentna 15294300 52 20 6.0 0.05 -- --
91 7.4
77 24 12 0.18 ---130 7.1
Lowe River near Valdez 15226500 57 3.2 0.8 0.32 ----100 7.6
46 22 1.2 0.34 ----77 7.3
Fortymile River near Steel Creek -65 37 0.5 0.47 ----116 7.4
TABLE E.10.36:FUEL AVAILABILITY FOR WOOD AND MUNICIPAL WASTES
Ra i I belt Da i Iy Tons Wood Fuel Municipal Refuse
Region (Tons/Day)(Tons/Day)
Greater Anchorage 200 -600 400
Kenai Peninsula 60 -180
Fairbanks 10 -30 150
Nenana 40 -140
-
TABLE E.l0.37:APPROXIMATE REQUIRED TEMPERATURE OF GEOTHERMAL FLUIDS
FOR VARIOUS APPLICATIONS
-
-
"""'
°c
200
190
180
Saturated 170
Steam
160
150
140
130
120
110
100
90
80
Hot 70
Water
60
50
40
30
20
Evaporation of highly concentrated solutions
Refrigeration by ammonia absorption
Digestion in paper pulp (Kraft)
Heavy water via hydrogen sulfide process
Drying of diatomacious earth
Drying of fish meal
Drying of timber
Alumina via Bayer's process
Drying farm products at high rates
Cann i ng of food
Evaporaton in sugar refining
Extraction of salts by evaporation and crystal I ization
Fresh water by distillation
Me st mu It i -ef fect evapora ti on;concentrat i on of sa line
solution
Dry i ng and cur i ng of aggregate slabs
Drying of organic materials,seaweeds,grass,
vegetabl es,etc.
Washing and drying of wool
Drying of stock fish
Intense de-icing operations
Space-heat ing (bui Id ings and greenhouse)
Refr igeration (lower tanperature limit)
Animal husbandry
Greenhouses by comb i ned space and hotbed heat i ng
Mushroom growing
Sa I neology
Soil warming
Swimming pool s,biodegradation,fermentations
Warm water for year-round mining in cold cl imates
De-icing
Hatching of fish;fish farming
Co nvent ional power
production
...J 1 )1 ---1 -)J )J )
PREVIOUS
STUDIES AND
FIELD
RECONNAISSANCE
SCREEN
ENGINEERING
LAYOUT AND
COST STUDIES
COMPUTER MODELS
TO DETERMINE
LEAST COST DAM
COMBINATIONS
DATA ON DIFFERENT
THERMAL GENERATING
SOURCES I
---II COMPUTER MODELS I
TO EVALUATE
-POWER AND
ENERGY YIELDS
-SYSTEMWIDE
ECONOMICS
CRITERIA
ECONOMIC
ENVIRONMENTAL
SOCIAL
ENERGY
CONTRIBUTION
WATANA I DEVIL
CANYON
PLUS Tt-£RMAL
LEGEND
~STEP NUMBER IN
STANDARD PROCESS
(APPENDIX A)
ADDITIONAL SITES
PORTAGE CREEK
DIS HIGH DEVIL CANYON
DIS WATANA
OBJECTIVE
ECONOMIC
WATANA I DEVIL
CANYON
I I HIGH DEVIL
CANYON I VEE
HIGH DEVIL
CANYON /WATANA
CRITERIA DEVIL CANYON
ECONOMICS HIGH DEVIL
ENVIRONMENTAL .CANYON
ALTERNATIVE WATANA
SITES SUSITNA m
ENERGY VEE
CONTRIBUTION MACLAREN
DENALI
GOLD CREEK
DEVIL CAN'ft>N
HIGH DEVIL CAN'tON
DEVIL CREEK
WATANA
SUSITNA m
VEE
MACLAREN
DENALI
BUTTE CREEK
TYONE
SUSITNA BASIN PLAN FORMULATION AND SELECTION PROCESS
FIGURE E.IO.I
...~"
./
/
."----.....
.\27
GJ'-ANIJNA~...~
SELECTED ALTERN,
RIVER /.,
~...~?..
FAIRBANKS
-.
9-...-----
40
I~
ATIVE HYDROELECTRIC SITES
LEGEf"W:
&.0-25 MW
c:J 25 -100 MW
<:)>100 MW
I.STRANDLINE L.
2.LOWER BELUGA
3.LOWER LAKE CR.
4.ALLISON CR.
5.CRESCENT LAKE 2
6.GRANT LAKE
7.McCLURE BAY
8.UPPER NELLIE JUAN
9.SILVER LAKE
10.SOLOMON GULCH
II.TUSTUMENA
12.WHISKERS
13;COAL
14.CHULITNA
15.OHIO
16.LOWER CH ULITNA
17.CACHE
18.GREENSTONE
19.TALKEETNA 2
20.GRANITE GORGE
21.KEETNA
22.SHEEP CREEK
23.SKWENTNA
24.TALACHULITNA
25.SNOW
26.KENAI LOWER
27.GERSTLE
28.TANANA R.
29.BRUSKASNA
30.KANTISHNA R.
31.UPPER BELUGA
32.COFFEE
33.KLUTINA
34.BRADLEY LAKE
35.HICK'S SITE
36.LOWE
37.LANE
38.TOKICHITNA
39.YENTNA
40.CATHEDRAL BLUFFS
41.JOHNSON
42.BROWNE
43.TAZILNA
44.KENAI LAKE
45.CHAKACHAMNA
o 20 40 MILES
SCALE (APPROXIMATE)~i~~liiiiiiiiiiiiiiiiiiiiiiiii.
FIGURE E.IO.2
3
1954
715
245 :!!I!!!!i!!i!ii!i!!O~~·.§L lli=:L -.1lliiEl --.Jllliilltl
2000 2010
;=
~
2ooo
I
>-....
U«ICl.«
U
10 LEGEND
CHAKACHAMNA
EXISTING AND COMMITTED
OIL FIRED THERMAL(NOT SHOWN ON ENERGY DIAGRAM)
COAL FIRED THERMAL
GAS ~RED THERMAL
HYDROELECTRIC
NOTE:RESULTS OBTAINED FROM
OGP5 RUN L FL 7
D•[Z]•8
2
>-
(!)
ffi4
Zw
::t:
;=6(!)
ooo
OL.--.....L..-..........---------......;....------------.......
1980 1990 2000 2010
TIME
GENERATION SCENARIO INCORPORATING THERMAL
AND ALTERNATIVE HYDROPOWER DEVELOPMENTS
-MEDliUM LOAD FORECAST-FIGURE E.IO.3
--1 1
SITE
SELECTION
1
PREVIOUS
STUDIES
')
CRITERIA
ECONOMICS
ENVIRONMENTAL
4 ITERATIONS
J 1
ENGENEERING
LAYOUTS AND
COST STUDIES
OBJECTIVE
ECONOMICS
DATA ON DIFFERENT
THERMAL GENERATING
SOURCES
COMPUTER MODELS TO
EVALUATE
-POWER AND
ENERGY YIELDS
-SYSTEM WIDE
ECONOMICS
CRITERIA
ECONOMICS
1 J
CH,K,S a THERMAL
LEGEND
SNOW {S}
BRUSKASNA (B)
KEETNA (K)
CACHE (CA)
BROWNE (BR)
TALKEETNA - 2 (T-2)
HICKS (H)
CHAKACHAMNA (CH)
ALLISON CREEK {AC}
STRANDLINE LAKE (SL)
-CHI K
-CH I K IS
-CHI K I SIS L ,AC
-CH,K,S,SL,AC
-CH ,K,S,SL,AC ,CA,T-2 -~STEP NUMBER
IN STANDARD
PROCESS
(APPENDIX A)
FORMULATION OF PLANS INCORPORATI.NG NON-SUSITNA HYDRO GENERATION
FIGURE E.IO.4
}J 1 ]1
~
lEGEND:
&DAM SITE
c,«.'//,7
;--0'--
/'·'-.f·--......_.\J .
['.I('.,
..................--.........D ('L~0 "~.),,-.'~/~'\,~y .
""'"''-.-........'V""I \
\"L'~
("-'.',-'--.-.--..-.../v \c-~~\,..'-'/\'-'-'I ('v'.-.....,\/---.../'I /"'--:-'---.~~--/.__..-...-c,.:.......----\
'POfl1·G,~.~~.'\J ,~,../""~,"p"~·'-/·~L ,~;'","~/--..,",'~)
/ ./OLSON CANYON DEVIL CREEK ,e'·...7 ,....-.
(",\~E.~>---..,J o../'
.GOLD HIGH ."'--""""\::<:''1'MaclAREN ..-1'CREEK "t;~~.-/
.D.C..-""'1.SUSITNA :or ~
\,.,·-""""·_·/·'-......,,-·v --j',(NODEFINITE :.~\
.lOCATION)(J I ,,''J.:"~f ~,L::?,"/'>-"'0~l J~:'v-..:::.,.,'1'~~t''"\.....C\.
1""}\~E.'"".".~','",;,:'"~~L,,~'\..'!~\(~,~TYONE~~·.Ij.
"\/I /\~~~f~2 \
UPPER SUSITNA ~-----.'1"((~c>};\\SU~~~;--)
.WATERSHED BOUNDARY',.I",~\.~Z\..(~(~R""
'\"~!y ..........")i .
• ,U'.........~E.~~t.,,"(\'"\~or v .~(.,'.''''£<=''~.J..~,.,""\(I .I ,,-._-.-.-.
. ((-.r--,_...1'"-,),-y"',
L·,-..-'·SCALE v 10 20 MILES
DAMSITES PROPOSED BY OTHERS
FIGURE E.IO.5
ALTERNATIVE
R.5E.
ACCESS -CORRIDORS
R.4 E.
T.lIN.
o 4 8 MILES
T.ION.SCALE ~i~~...._.!
T.9N.
T.8N.
T.7N.
FIGURE E.IO.6
o 4 8 MILES
SCALE ••-_~~::r!
ALTERNATIVE ACCESS.PLAN 13 (NORTH)
FIGURE E aIO.?
R./2W.R.IIW.
T.32N.
T.30 N.
T.27N.
R.3W.R.2W.R.IW.R.IE.R.2E.R.3E.R.4E.R.5E.
ALTERNATIVE ACCESS PLAN 16 (SOUTH)
FIGURE E.IO.8
ALTERNATIVE ACCESS PLAN 18 (PROPOSED)
FIG URE E.10.9
-
ALTERNATIVE TRANS
SOUTHEF
MISSION LINE CORRIDORS
N STUDY AREA
LOCATION MAP
LEGEND
- - -STL'DY CORRIDOR
.•••••••.••••.I NTERTIE
(APPROXIMATE)
o 5 10iI
SCALE IN MILES
FIGURE E.lO.IO
ALTERNATIVE TRAN~
CENTRAl
FAIRBANKS
MT.McKINLEY ./'
',/
.'/
LOCATION MAP
-
LEGEND
---STUDY CORRIDOR
•••••••••..••.I NTERTIE
(APPROXIMATE)
MISSION LINE CORRIDORS
STUDY AREA
o 5
i
SCALE IN MILES
10
I
FIGURE E.IO.II
ALTERNATIVE TRAN:
NORTHE
SMISSION LINE CORRIDORS
:RN STUDY AREA
SCALE IN MILES
lOCATION MAP
....
LEGEND
- - -STUDY CORRIDOR
.•••••••••••••I NTERTIE
(APPROXIMATE)
o 5 10~1~~~~~iiiiiiiiii~!
SCALE IN MILES
FIGURE E.IO.12
WATA~A
REL.,jCtr CHANNEl,
FOG LAKES
RELICT CHANNEL
/\
o 4 e MILES
SCALE ~i~~liiiiiiiiiiiiiiii.il!
LOCATION MAP
~
"'---
/'r--'
..f l
;
i
\
"
........
"
LEGEND
L~~:J BORROW /QUARRY SITE LIMITS
o 1·-
SCALE ~i~~~~~f MILES
WATANA
BORROW SITE MAP
FIGURE E.IO.13
,,
.4(;<,j :
.........~
o~ax...•.•...J':.g
"
,,/("
{:......,>
..,2f()0
o
,
".
".
",
/
o~},;':Ii!,Q9P .
.!i},??~.'0!Q .
REFERENCE'BASE MAP FROM RaM,IHI -,',200'
DEVIL CANYON TOPOQIlAPHY.
COORDINATES IN FEET,ALASKA STATE PLANE (ZONE 4)
o 4 8 MILES
SCALE ~i~~~liiiiiiiiiiiiiiiiiiiil
1"1000'
'-.500'
1"500'
1'·500'
1"500'
1'01000'
*SCALEAREACOVERED
80RROW SITE G
EXPLORATION
OAMSlTE'TOP OF 8EDROCK
GEOLOGIC MAP
TAILRACE AREA
QUARRY SITE K
INDEX
BLOCK
NO.
CD
®
®
®
LOCATION MAP
,....<.;;>~:~..x.=~.~:
'Pi -'t\,.~:§\<'-J\
¢.:Sl f~\
w '$};:1~l l},-~
:t-cc
",..
./
......-,.
LEGEND
m&l BORROW /QUARRY SITE LIMITS
*SCALE AFTER REDUCTION
.....,..
~..-'.NOTES
I.TOPOGRAPHY AND DETAILS SHOWN ON INDIVIDUAL
FIGURES .
EVIL CANYON
INDEX MAP
..,.
-_:'.
:..,
i ~
..".'.
O...~~I~OOO~iiiiiiii~2~OOO FEETSCALEct
FIGURE E.IO.14
SITE LIST
I.POINT MACKENZIE
2.EAGLE BAY
3.RAINBOW
(APPROX.)
FIGURE E./O.15
oSCALEi 37 74 MILES!
~
o
CD
V
POTENTIAL TIDAL POWER SITES
~
o
N
10
®
ILIAMNA LAKE"
I ~'il!I62°N ------r----."-.
,....
,
r
p-
I
r
,....
i
i
r
,....
l
GLOSSARY
Alder - a plant of the genus Alnus usually growing in wet areas which
provides cover for wildlife
Alluvium -deposits resulting from operations of river
Amphipods -order of crustacean which includes shrimp
Andesite - a volcanic rock composed of a certain mineral group and
one or more mafic constituents
Argillite - a compact rock derived from mudstone or shale
Basal till -nonsorted,nonstratified sediment carried or deposited
from the undersurface of a glacier
Batholith - a mass of igneous rock intruded as the fusion of older
formations '
Benches an area of relatively narrow earth or rock which is raised
Biotite - a mineral which is a member of the mica group
Dikes -tabular body of igneous rock that cuts across the structure
of adjacent rocks or cuts massive rocks
Diorite - a coarse grained intrusive igneous rock
-The Fins·-a geologic feature at the,immediate upstream boundary of
the Watana dam which i's the predominate shear zone at the site
Fluvial -.pertaining to rivers or produced by river action
Glacial moraine -drift mterial deposited by glaciers
Gneissic texture -having the texture of coarse-grained rock in which
bands rich in granular minerals alternate with bands in which
metamorphic rock with mica dominate
Granodiorite - a group of coarse grained plutonic rock
Graywacke -a gray or greenish gray very hard coarse grained sand-
stone with dark rock and minerftl fragments
High Enthalpy Fluids -liquids with a higher heat content
Homogeneous rock -rock comprised of the same material
Interfingered -rock which grades or passes from one material to the
other through a series of interlocking or overlapping wedge-shaped
layers
Isopods -order of crustacean which includes pillbugg
Lithology -the study of rocks
Low enthalphy fluids -liquids with a low heat content
Mafic -composed primarily of igneous rocks and their constituent
minerals
Murres -a species of marine fish-eating .birds
Muskeg -alluvial areas with insufficient drainage over which moss
has accumulated
Pelecypods -class of molluscs including clams and mussels
Polychaete worms -segmented worms such as earthworms
Puffins -a group of species of marine fish eating birds
Riprap -broken rock used for the protection of bluffs,structures,
or shoreline exposed to wave action or water
Sills -intrusive bodies of igneous rock of approximately uniform
thickness and relatively thin compared with its lateral extent
Solifluction -the process of slow flowage from higher to lower
ground of masses of waste saturated with water
Stratigraphy -the branch of geology which tracks the formation,
composition,sequence,and correlation of the stratified rocks as
part of the earth's crust
Swale -a low lying usually damp area along a stream characterized by
vegetative species of wet habitats
Talus -a collection of fallen disintegrated material which has
formed a slope at the foot of a steeper slope
Thermistor plots -the output of temperature recordi ng devi ces
Viewshed -the area that can be seen from one certain point
-
-!
i
!
-I
j
i
!-!