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Susitna-Watana Hydroelectric Project Document
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Title:
Characterization and mapping of aquatic habitats, Study plan Section 9.9 :
Initial study report
SuWa 207
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Prepared by R2 Resource Consultants, Inc.
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Draft initial study report
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Susitna-Watana Hydroelectric Project document number 207
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[Anchorage : Alaska Energy Authority, 2014]
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February 2014
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Alaska Energy Authority
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Study plan Section 9.9
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Draft
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182 p. in various pagings
(including all parts)
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Notes:
The following parts of Section 9.9 appear in separate files: Main report ; Appendix A ; Appendices
B-C ; Appendix D.
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produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
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Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Characterization and Mapping of Aquatic Habitats
Study Plan Section 9.9
Initial Study Report
Prepared for
Alaska Energy Authority
Prepared by
R2 Resource Consultants, Inc.
February 2014 Draft
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TABLE OF CONTENTS
Executive Summary ..................................................................................................................... vi
1. Introduction ....................................................................................................................... 1
2. Study Objectives................................................................................................................ 2
3. Study Area ......................................................................................................................... 3
4. Methods .............................................................................................................................. 4
4.1. General Overview of Habitat Mapping Methods...............................................4
Remote line mapping using Aerial Imagery ....................................5 4.1.1.
Overview of Ground Mapping Survey Protocols ............................9 4.1.2.
4.2. Upper River Habitat Mapping .........................................................................12
Tributaries in the Upper River .......................................................12 4.2.1.
Mainstem habitats in the Upper River ...........................................13 4.2.2.
Lakes within the Upper River Inundation Zone ............................14 4.2.3.
Variances from the Study Plan ......................................................15 4.2.4.
4.3. Middle River Habitat Mapping ........................................................................17
Tributaries in the Middle River......................................................17 4.3.1.
Mainstem Habitats in the Middle River .........................................18 4.3.2.
Variances from the Study Plan ......................................................18 4.3.3.
4.4. Lower River Habitat Mapping .........................................................................21
5. Results .............................................................................................................................. 21
5.1. Upper River ......................................................................................................21
Tributaries in the Upper River .......................................................22 5.1.1.
Mainstem Habitats in the Upper River ..........................................23 5.1.2.
Lakes Within the Upper River Inundation Zone............................24 5.1.3.
5.2. Middle River ....................................................................................................24
Tributaries in the Middle River......................................................24 5.2.1.
Mainstem Habitats in the Middle River .........................................25 5.2.2.
5.3. Lower River .....................................................................................................28
6. Discussion......................................................................................................................... 28
6.1. Study Coordination and Updates .....................................................................28
7. Completing the Study ..................................................................................................... 29
8. Literature Cited .............................................................................................................. 29
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9. Tables ............................................................................................................................... 31
10. Figures .............................................................................................................................. 61
LIST OF TABLES
Table 1.1-1. Nested and tiered habitat mapping units and categories for macrohabitats and
mainstem channel mesohabitats. ................................................................................................... 32
Table 1.1-2. Nested and Tiered Habitat Mapping Units and Hydraulic Categories Used for
Mesohabitats in Tributary Surveys. .............................................................................................. 34
Table 4.1-1. Upper River Tributary Table Showing all Tributary Geomorphic Reaches, Gradient,
Basin Area, Private Land Ownership, and 2013 Survey Status. ................................................... 35
Table 4.1-2. . Middle River Tributary Geomorphic Reaches Selected for Field-Survey, Gradient,
Basin Area, Private Land Ownership, and 2013 Survey Completion Status. ............................... 36
Table 4.1-3. Tributary geomorphic reach mesohabitat frequency and composition derived from
videography 2012.......................................................................................................................... 37
Table 4.2-1. Randomly selected Upper and Middle River mainstem habitats versus those
surveyed during 2013. ................................................................................................................... 38
Table 4.2-2. Lakes in the Upper River located within the inundation zone, and habitat metrics
obtained from the Project GIS database. ....................................................................................... 39
Table 4.2-3 Project River Mile ranges for areas not surveyed due to access restrictions due to
private land and safety considerations. ......................................................................................... 40
Table 4.2-4. Range of mean daily flows at the USGS 15292000 Susitna River at Gold Creek real
time streamflow gage during 2013 ground surveys. ..................................................................... 41
Table 4.3-1. Focus Area habitats surveyed during 2013, and those required for survey in the next
year of study to complete 100 percent sampling. ......................................................................... 42
Table 5.1-1. Sum of length (m) surveyed, and composition by length of mesohabitats in Upper
River and Middle River tributaries surveyed between August 3 and September 22, 2013. ......... 43
Table 5.1-2. Mean (±SD) percent gradient of mesohabitats in Upper River and Middle River
tributaries surveyed between August 3 and September 22, 2013. ................................................ 44
Table 5.1-3. Mean (±SD) bankfull width (m) of mesohabitats in Upper River and Middle River
tributaries surveyed between August 3 and September 22, 2013. ................................................ 45
Table 5.1-4. Mean (±SD) wetted width (m) of mesohabitats in Upper River and Middle River
tributaries surveyed between August 3 and September 22, 2013. ................................................ 46
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Table 5.1-7. Number of mesohabitats within macrohabitats measured for length, sum of length
(m) surveyed, and composition by length in macrohabitats among geomorphic reaches and
survey types in Upper River and Middle River mainstems surveyed between August 2 and
September 17, 2013. ..................................................................................................................... 49
Table 5.1-8. Sample size and mean (±SD) of percent gradient measurements made among
geomorphic reaches and survey types by macrohabitat in Upper River and Middle River
mainstem surveyed between August 2 and September 17, 2013. ................................................. 50
Table 5.1-9. Sample size and mean (±SD) of bankfull width measurements made among
geomorphic reaches and survey types by macrohabitat in Upper River and Middle River
mainstem surveyed between August 2 and September 17, 2013. ................................................. 51
Table 5.1-10. Sample size and mean (±SD) of wetted width measurements made among
geomorphic reaches and survey types by macrohabitats in Upper River and Middle River
mainstem surveyed between August 2 and September 17, 2013. ................................................. 52
Table 5.1-11. Sample size and mean (±SD) of bankfull depth measurements made among
geomorphic reaches and survey types by macrohabitats in Upper River and Middle River
mainstem surveyed between August 2 and September 17, 2013. ................................................. 53
Table 5.1-12. Sample size and mean (±SD) of thalweg depth measurements made among
geomorphic reaches and survey types by macrohabitats in Upper River and Middle River
mainstem surveyed between August 2 and September 17, 2013. ................................................. 54
Table 5.1-13. Number of mesohabitats measured for length, sum of length (m) surveyed, and
composition by length of mesohabitats among geomorphic reaches and survey types in Upper
River and Middle River mainstems surveyed between August 2 and September 17, 2013. ........ 55
Table 5.1-14. Sample size and mean (±SD) of percent gradient measurements made among
geomorphic reaches and survey types in mesohabitats in Upper River and Middle River
mainstems surveyed between August 2 and September 17, 2013. ............................................... 56
Table 5.1-15. Sample size and mean (±SD) of bankfull width measurements made among
geomorphic reaches and survey types in mesohabitats in Upper River and Middle River
mainstems surveyed between August 2 and September 17, 2013. ............................................... 57
Table 5.1-16. Sample size and mean (±SD) of wetted width measurements made among
geomorphic reaches and survey types in mesohabitats in Upper River and Middle River
mainstems surveyed between August 2 and September 17, 2013. ............................................... 58
Table 5.1-17. Sample size and mean (±SD) of bankfull depth measurements made among
geomorphic reaches and survey types in mesohabitats in Upper River and Middle River
mainstems surveyed between August 2 and September 17, 2013. ............................................... 59
Table 5.1-18. Sample size and mean (±SD) of thalweg depth measurements made among
geomorphic reaches and survey types in mesohabitats in Upper River and Middle River
mainstems surveyed between August 2 and September 17, 2013. ............................................... 60
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LIST OF FIGURES
Figure 3-1. Aquatic habitat and mapping study area during 2013 field effort. ............................ 62
Figure 4.1-1 Flows during mainstem Susitna River in 2011, 2012 and 2013 with the timing of
2013 field surveys superimposed. ................................................................................................. 63
Figure 4.1-2. Map of Upper River tributaries with tributaries selected for field-surveys identified.
....................................................................................................................................................... 64
Figure 4.2-1 Map of Upper River basin lakes within the potential zone of reservoir inundation. 65
Figure 4.4-1 Aerial video capture of the Lower Susitna River mainstem showing highly complex
braided channels characteristic of main channel habitats in this river section. ............................ 66
APPENDICES
Appendix A: Remote Line Mapping, 2012
Appendix B: Upper Susitna River Segment Remote Line Habitat Mapping Technical
Memorandum
Appendix C: Upper River Mainstem Surveys, 2013
Appendix D: Middle River Mainstem Surveys, 2013
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LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
ADF&G Alaska Department of Fish & Game
AEA Alaska Energy Authority
ARRC Alaska Railroad Corporation
BFD measured bankfull depth
BFW measured or estimated bankfull width
cfs Cubic Feet per Second
CIRWG Cook Inlet Region Working Group
FA Focus Area
FERC Federal Energy Regulatory Commission
ft feet
GIS Geographic Information System
IFSAR Interferometric Synthetic Aperture Radar
ISR Initial Study Report
LB Left Bank – looking downstream
Level 3 Mainstem Habitat
Level 4 Mainstem and Tributary Mesohabitat
LiDAR Light Detection and Ranging. An optical remote sensing technology that can measure the
distance to a target; can be used to create a topographic map.
LWD Large Woody Debris
m meter(s)
mi mile(s)
NHD National Hydrography Database
PRM Project River Mile
RB Right Bank – looking downstream
RM River Mile(s) referencing those of the 1980s APA Project
RSP Revised Study Plan
SPD Study Plan Determination
TWG Technical Workgroup
USFS United States Forest Service
USGS United States Geological Survey
USR Updated Study Report
yd yard
ZHI Zone of Hydrologic Influence
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EXECUTIVE SUMMARY
Characterization and Mapping of Aquatic Habitats Study 9.9
Purpose This study maps and characterizes habitat at multiple scales across both the
Susitna River mainstem and tributaries. These data provide baseline habitat
characterization that, along with data from other studies, will support
assessment of potential impacts of the proposed Project.
Status Complete coverage by remote line mapping in the Susitna River mainstem and
tributaries was completed in 2012. In 2013, ground truthing of the remote
mapping effort was initiated in both the mainstem and tributaries as well as
mesohabitat mapping in areas not amenable to remote line mapping. Field data
collection will be completed during the next year of study.
Study
Components
Remote line mapping consisted of data from aerial imagery supplemented with
information from videography to generate a geospatial database.
Ground truthing surveys were conducted in a subset of mesohabitat and
macrohabitat segments in 2013 and will continue in the next year of the study.
Focus areas will be 100 percent ground-surveyed to the level of mesohabitat to
provide detailed information for the Instream Flow Study (Study 8.5) needs.
Mesohabitat characterization in a random subset of habitat units using a
modified USFS stream survey protocol (USFS 2001) will allow comparisons
among habitat types along the river continuum.
Variances in
2013
AEA implemented the methods as described in the Study Plan with the
exception of the following variances. The significance of these variances is
discussed within the ISR.
Physical access limitations and safety concerns restricted the scope of random
sampling (RSP Sections 9.9.5.3.2 and 9.9.5.4) to habitat units (ISR Sections
4.2.4.1 and 4.3.3.1).
Special habitat features were expanded from the Study Plan (SPD B-210) to
include backwaters, beaver complexes and clearwater plumes (ISR Sections
4.2.4.2 and 4.3.3.2).
Ground survey flow conditions were more variable than anticipated (RSP
Section 9.9.5.3.2) due to unexpected late summer high flows, this affected a
small number of habitat units that were surveyed at flows higher than those
under which the reference imagery was obtained (ISR Sections 4.2.4.3 and
4.3.3.3). Careful preplanning largely limited these habitats to those where
habitat calls were least likely to be altered by variation in flow conditions. An
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Characterization and Mapping of Aquatic Habitats Study 9.9
assessment of any resulting discrepancies between remote mapped and ground-
truthed habitat classifications will be presented in the Updated Study Report.
Steps to
Complete the
Study
As explained in the cover letter to this draft ISR, AEA’s plan for completing
this study will be included in the final ISR filed with FERC on June 3, 2014.
Highlighted
Results and
Achievements
Remote imagery (aerial photography, aerial videography, and LiDAR) were
used to complete the aquatic habitat mapping of the entire Upper and Middle
Susitna River. All habitats were mapped to the macrohabitat level (side slough,
side channel) and the Upper and Middle River main channel habitats were
mapped to the mesohabitat level (pool, riffle, run) within a macrohabitat type.
Field surveys were conducted to ground-truth the mapping from remote
imagery and to provide further characterization of aquatic habitats. The field
effort covered 40,241 m (25 mi) of tributary habitat in 19 tributaries and 42,554
m (26.4 mi) of mainstem aquatic habitat and characterized these habitats using
a modified USFS survey protocol.
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1. INTRODUCTION
On December 14, 2012, Alaska Energy Authority (AEA) filed its Revised Study Plan (RSP) with
the Federal Energy Regulatory Commission (FERC or Commission) for the Susitna-Watana
Hydroelectric Project (FERC Project No. 14241) which included 58 individual study plans (AEA
2012a). Included within the RSP was the Characterization and Mapping of Aquatic Habitats,
Section 9.9. RSP Section 9.9 focuses on describing the aquatic habitats of the Susitna River
using a specific hierarchical and nested classification system based on historic and current data.
On February 1, 2013, FERC staff issued its study determination (February 1 SPD) for 44 of the
58 studies, approving 31 studies as filed and 13 with modifications. FERC requested additional
information before issuing a SPD on the remaining studies. On April 1, 2013 FERC issued its
study determination (April 1 SPD) for the remaining 14 studies; approving 1 study as filed and
13 with modifications. RSP Section 9.9 was one of the 13 approved with modifications. In its
April 1 SPD, FERC recommended the following:
Edge Habitat
We recommend that AEA remove the level 5 calculation of edge habitat from the
habitat classification system.
Backwater and Beaver Dam Habitats
We recommend changing the classification of backwater, beaver complex, and
clearwater plume habitats from level 3 (mainstem habitat) to level 4 (mainstem and
tributary mesohabitats).
Classification of Upper River Tributaries
We recommend that AEA consult with the TWG and file no later than June 30, 2012,
the following information to quantify small and low-order tributaries in the Upper
River study area:
1) A detailed description of the specific methods to be used for selecting a
representative sample of small and low-order Upper River tributaries for aquatic
habitat mapping.
2) Documentation of consultation with the TWG, including how its comments were
addressed.
Habitat Mapping at Multiple Flows
We recommend modifying the study plan to have AEA identify and give specific
consideration to backwater habitats, as defined by the agencies (i.e., the confluence
of off-channel habitats with main channel habitats), as a unique habitat feature and
ensure a representative subsample of these locations when selecting transect
locations for one-dimensional or two-dimensional aquatic habitat modeling within
Middle River and Lower River instream flow study sites.
Classification of Middle and Lower River Tributaries
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We recommend modifying the study plan to have AEA classify Middle River tributary
reaches within the zone of hydrologic influence into geomorphic reaches based on
tributary basin drainage area and stream gradient to provide a general
understanding of the relative potential value to fish and aquatic resources, and report
on these attributes in the initial and updated study reports.
Habitat Mapping and Ground-Truthing
We recommend that AEA provide a detailed description of methods and results of
2012 and 2013 habitat mapping in the initial study report, including a complete set of
photographic base maps delineating macrohabitats (level 3) and mesohabitats (level
4) for all mapped locations.
Following the first study season, FERC’s regulations for the Integrated Licensing Process (ILP)
require AEA to “prepare and file with the Commission an initial study report describing its
overall progress in implementing the study plan and schedule and the data collected, including an
explanation of any variance from the study plan and schedule.” (18 CFR 5.15(c)(1)) This Initial
Study Report on Characterization and Mapping of Aquatic Habitats has been prepared in
accordance with FERC’s ILP regulations and details AEA’s status in implementing the study, as
set forth in the FERC-approved RSP and as modified by FERC’s April 1 SPD and includes the
Characterization and Mapping of Aquatic Habitats Technical Memorandum (HDR 2013) filed
with the Commission on July 16, 2013 (collectively referred to herein as the “Study Plan”).
2. STUDY OBJECTIVES
The study objectives were established in the Study Plan (RSP Section 9.9.2) and are described
below.
Upper River Habitats:
1. Characterize and map Upper River tributary and lake habitats for the purpose of
evaluating the potential loss or gain in available fluvial and lacustrine habitat that
may result from dam construction and inundation by the reservoir.
2. Characterize and map Upper River tributary and lake habitats for the purposes of
informing other studies including Fish Distribution and Abundance in the Upper
Susitna River (Study 9.5) and River Productivity (Study 9.8).
3. Characterize and map the Upper River mainstem (understood hereafter to
encompass both main channel and off-channel habitats) upstream from the
Watana dam site to the confluence with the Oshetna River:
i. To provide baseline data for the purpose of evaluating the potential loss
or gain in accessible available fluvial and lacustrine habitat that may
result from dam construction and inundation by the reservoir.
ii. To inform other studies including Fish Distribution and Abundance in
the Upper Susitna River (Study 9.5), River Productivity (Study 9.8), and
Future Watana Reservoir Fish Community and Risk of Entrainment
(Study 9.10).
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Middle River Habitats:
1. Characterize and map the Middle River mainstem from the Chulitna River confluence
to the proposed Watana Dam site, including tributaries within the zone of hydrologic
influence (ZHI) and the Focus Areas:
i. To provide baseline data for the purpose of evaluating the potential loss
or gain in accessible available fluvial habitat that may result from flow
regulation below the proposed Watana Dam.
ii. To inform other studies including Fish Distribution and Abundance in
the Middle and Lower Susitna River (Study 9.6), River Productivity
(Study 9.8), and Instream Flow (Study 8.5).
Lower River Habitats:
1. Characterize and map the Lower River mainstem from the upper extent of tidal
influence upstream to the Three Rivers Confluence:
i. To provide baseline data for the purpose of evaluating the potential loss or
gain in available fluvial habitat that may result from flow regulation below the
proposed Watana Dam.
ii. To inform other studies including Fish Distribution and Abundance in the
Middle and Lower Susitna River ( Study 9.6), River Productivity (Study 9.8),
and Instream Flow (Study 8.5).
3. STUDY AREA
As established by the Study Plan (RSP Section 9.9.4) and modified as described below, the study
area encompasses the mainstem Susitna River from the Oshetna River confluence at PRM 235.1
downstream to the upper extent of tidal influence. The mainstem study area is divided according
to geomorphic/hydrologic river segments; the Upper River, Middle River, and Lower River (see
Figure 3-1). The study area also encompasses tributaries in the Upper and Middle River. Note
that the study area for selected Upper River tributaries has been modified in accordance with the
Characterization and Mapping of Aquatic Habitats Technical Memorandum which was reviewed
by the agencies and filed with FERC on July 1 6, 2013 (HDR 2013).
The study area for habitat mapping and characterization is as follows:
• Upper River
o Tributaries: For selected streams in watersheds known to support Chinook
salmon, the habitat mapping study area extends up to 3,000 ft elevation, unless a
permanent impassable barrier exists between 2,200 and 3,000 ft elevation. If a
barrier exists within this range, surveys will stop at the barrier. In watersheds not
known to support Chinook salmon, the habitat mapping study area will terminate
at 2,200 ft elevation regardless of the presence of a barrier below this elevation.
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o Mainstem: Mainstem habitats from the Oshetna River confluence at PRM 235.1
to the proposed dam site at PRM 187.1 and focused on habitats within the
inundation zone of the proposed reservoir.
o Lakes: Lakes within the proposed reservoir inundation.
• Middle River:
o For selected tributaries above Devils Canyon known to support Chinook salmon,
the study area extends up to 3,000 ft elevation or the first impassable barrier,
whichever is less.
o For all other selected tributaries in the Middle River, the study area extends from
the confluence with the mainstem or off-channel up to the upper limit of the zone
of hydrologic influence (ZHI).
o Mainstem habitats of the Susitna River from PRM 187.1 downstream to the
Chulitna River confluence at PRM 102.4
• Lower River:
o The Lower Susitna River from PRM 102.4 to the upper extent of tidal influence.1
4. METHODS
This section of the ISR provides an updated and more detailed description of the methods relied
upon to meet the Study Plan objectives. To the extent that the methods have varied from the
method described in the Study Plan, those variances are described below.
4.1. General Overview of Habitat Mapping Methods
The Susitna River from the Oshetna River to its mouth (Upper, Middle and Lower River
segments combined) includes 235 miles of river and substantially more stream distance when the
lengths of side channels, braided channels, and sloughs are included. Ground-based habitat data
collection along the entire river is impractical due to the complexity of channel plan form, the
linear extent, and the remoteness of the river. For these reasons, an analysis of aerial imagery
was combined with ground-based habitat data collection covering a representative proportion of
river habitats to form a habitat characterization of the river. In addition, the ten Focus Areas that
1 The Study Plan (RSP Section 9.9.4) provided that AEA would consider the study area for the
Lower River segment to extend from PRM 235.1 downstream to the upper extent of tidal
influence, and noted this as approximately RM 28. Instead AEA adjusted the study area for the
Lower River segment to extend from PRM 235.1 to PRM 3.3. Mapping and characterization in
the Lower River segment has been completed (see Section 4.4) using information from the
Geomorphology Study (ISR 6.5). This change in study area boundaries for the Lower River will
allow AEA to better meet the objective of mapping and characterizing habitat in this river
segment by aligning boundary descriptions between these studies.
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were identified and described in the Technical Memorandum: Adjustments to Middle River
Focus Areas (R2 Resource Consultants 2013a) were targeted for 100 percent mapping coverage
using both aerial imagery and ground-based surveys. This combination of methods allowed for
optimum spatial coverage of river habitats in concert with efficient collection of detailed data at
selected habitats. Habitat characterization methods were tailored to accommodate variations in
channel size and overall stream length. This approach used various mapping methods and tools
to meet multiple study objectives and provides the best possible coverage and characterization of
river habitats in a large, complex river basin.
Because potential project effects are different in different geomorphic segments of the river,
habitat mapping methods were differentiated within the study area first by major geomorphic
segment (Upper River, Middle River, and Lower River). Methods were further differentiated by
tributary, main channel, off-channel and lake habitat to accommodate the major differences in
morphology and hydrology among these habitats. Habitat data collected in this study used the
Susitna-Watana Hydroelectric Project habitat classification system (Table 1.1-1) developed
during the 2012 study design and planning process as well as standard protocols outlined in the
USFS Aquatic Habitat Surveys Protocol (USFS 2001).
Preliminary segment-specific data based on 2012 and 2013 study efforts are reported using tables
of macro- and mesohabitat type frequency and summary tables of select measured mesohabitat
characteristics (Section 5).
Remote line mapping using Aerial Imagery 4.1.1.
During the 2012 remote line mapping effort, data derived from aerial imagery were
supplemented with information from video mapping to generate a geospatial database within a
GIS (geographic information systems) framework. Remote line mapping of habitats in the study
area was completed using a hierarchically-nested habitat typing system that was adapted to the
identification levels deemed feasible based on the available aerial imagery (Table1.1-1,
Appendix A). The habitat classification hierarchy was composed of four levels representing: (1)
major hydrologic segment; (2) geomorphic reach (RSP 6.5.4.1.2.2 and RSP Table 6.5-1); (3)
macrohabitat type (Table 1.1-1); and (4) mesohabitat type (Mainstem, Table 1.1-1; Tributary,
Table 1.1-2).
For remote line mapping, all main channel habitats were identified to Level 4 mesohabitat type
(riffle, pool, run, etc.). Mapping main channel habitats to the mesohabitat level from remote
imagery was challenging for certain habitat types that included differentiating run and glide
habitat and identifying pool habitat. Run and glide habitat was closely examined through aerial
stills and videography to make a professional judgment of the habitat type; however, wind-waves
and glare can confound the typing of these habitats. Pool habitat required identifying a hydraulic
control and was only found in the Devils Canyon area, where the control was very obvious.
Small, less obvious pools may have not been identified from this methodology.
Off-channel habitat (which includes side and upland sloughs) and most tributaries were classified
to Level 3 (macrohabitat). These units were not classified into mesohabitats in the remote line-
mapping due to the lack of resolution of aerial imagery and the confounding presence of
shadows or riparian cover. To address this issue, a subset of 10 primary and 3 secondary
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tributaries were habitat typed to Level 4 (mesohabitat) using the results of the 2012 videography
as discussed in Section 4.1.1.2 and further described in Appendix 2 of the Fish Distribution and
Abundance Implementation Plan (R2 Resource Consultants 2013b). An additional 15 smaller
primary and secondary tributaries were identified for ground surveys following the FERC April
1 SPD and in consultation with the TWG via agency review of the Technical Memorandum:
Characterization and Mapping of Aquatic Habitats (HDR 2013) during July of 2013. During the
2013 field effort, off-channel habitats were specifically targeted during the random selection of
habitat units for field surveys to characterize these habitats to the level of mesohabitat (Sections
4.2.2 and 4.3.2). Field data will be available after 2013 to verify aerial imagery and video
typing. If large discrepancies in the proportion of habitat types are apparent upon comparing
remote and field mapping data; these results will be presented in the Updated Study Report
(USR).
4.1.1.1. GIS Habitat Mapping
A linear network was created in GIS by drawing vector-lines (segments) along the stream
channel center line as viewed by aerial imagery or LiDAR. This reference imagery was
collected at river flows generally ranging from 10,000 to 12,000 cfs, which was subsequently
considered representative of relatively low to moderate flow levels. Mainstem habitats were
uniquely identified and delineated into segments. Divided channels were assigned multiple
segments. The lengths of the segments were based on mesohabitat classifications for the main
channel and macrohabitat classifications for off-channel habitats (Table 1.1-1). Each individual
vector line segment in the GIS was thus associated with a length and a hierarchical-tiered habitat
classification. Not all lines were connected into a contiguous or flow-based network. Note that
since there could be multiple macrohabitat types laterally distributed within the floodplain, the
total length of habitat identified during remote line mapping could have been considerably longer
than the length of each geomorphic reach.
While mapping the mainstem in GIS, tributaries also were delineated in the aerial imagery up to
0.5 mi from the centerline of the main channel or off-channel confluence. Tributaries were
differentiated from upland sloughs based on their gradient characteristics and whether they
originated above the floodplain. The exact locations of some tributary segments were difficult to
determine using the available imagery in heavily forested areas. These locations were estimated
based on visual cues in the canopy. Tributary mouths were mapped using a single line segment
showing the length of the wetted area of the tributary mouth that extended from the vegetation
line out to the edge of the gravel bank. In some of the larger tributaries, the mouth habitat was
extended inland beyond the vegetation line based on visible habitat breaks between the tributary
channel and the alluvial gravel areas at the mouth.
Within the Upper River tributaries, macrohabitats were mapped from aerial imagery.
Matanuska-Susitna Borough LiDAR and imagery were available for the lower extent of many
tributaries. However, overhanging vegetation, shadows and other environmental conditions
limited characterization of mesohabitats from these sources. In higher elevations within
tributaries, mesohabitat characterization was not possible from aerial imagery due to a lack of
high resolution photography. A subset of 17 tributaries was thus selected for mesohabitat typing
by videography as described in Section 4.1.1.2.
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Aerial imagery, was used to further classify mainstem habitat into mesohabitats (Table 1.1-1).
Aerial still imagery was viewed at a range of scales from 1:1,000 to 1:12,000 and 2012
videography was referenced as needed. All habitat units were identified using a mid-channel
line, which was measured to provide habitat length (HDR Alaska, Inc. 2013a, Appendix B). In
channels that were only partially inundated or where water was present in sloughs, the line
segments followed the wet areas. AEA has estimated macro- and mesohabitat frequency within
main channel, off-channel and tributary study areas based on these data (HDR Alaska 2013a,
Appendix B).
Main channel macrohabitats in the Susitna River were classified as single main channel when
only a single dominant channel was present; split main channels when the flow was dispersed
into two relatively evenly sized channels where the bar or island separating the channels was not
vegetated; and multiple split main channels when the main channel split into three or more
separate channels each carrying a significant portion of the flow.
Side channels were completely inundated with turbid water (or contained portions that held
turbid water), connected at both upstream and downstream ends to the main channel, and flowing
around a permanently vegetated island. The dry portions of the channel were delineated based
on substrate and a lack of any vegetation, indicating that water periodically inundated the
channel during higher flow periods. The distance that the side channel line segments extended
into the main channel was determined by an estimation of the continuation of the vegetated or
high water shoreline on either side of the mouth of the side channel. The presence of clear or
turbid water was used as a main indicator to differentiate between sloughs and side channels.
Side sloughs had clear water and were only connected at the top of the channel to the main
channel at high flows. These areas could be partially dry but showed evidence that they were
inundated regularly during high flows by lack of vegetation. Upland sloughs had similar
characteristics in that the water was relatively clear, but these were not open to the main channel
at both ends as indicated by the presence of vegetation in the area between the upstream end of
the slough and the main channel.
Mesohabitats were classified from interpretation of both the GIS imagery and aerial video.
Riffles were distinguished from areas of wind waves or standing waves by the presence of white
water and protruding boulders in the area that indicated the water was relatively shallow and
passed over cobbles and boulders. Whitewater in a reach was classified as a run if only one or
two protruding boulders were producing isolated areas of turbulence.
Several controls were established to ensure that the remote habitat mapping effort was both
precise and accurate. Examples of specific aerial images of habitat types were created, reviewed
and confirmed by the technical lead and provided a voucher reference to help identify habitat
types. Final habitat typing was reviewed by the technical lead to ensure consistent and accurate
habitat mapping.
The exact location of habitat boundaries, such as the boundary between a riffle and run/glide,
often required professional judgment on the part of the mapper. Due to lack of resolution in the
aerial imagery and shadows along the left bank of the river, some habitat features such as
tributary mouths were confirmed by using aerial video as a secondary reference (Section
4.1.1.2). Aerial video was also used to confirm the more permanent gravel bars that showed
some vegetation, which was sometimes not evident in the aerial imagery. If the aerial video
indicated a bar had vegetation on it, but vegetation was not evident in the aerial imagery, the
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island was considered vegetated and the main channel line segment was separated into a main
channel segment containing the dominant portion of flow and a side channel segment around the
island.
Additional details on methods associated with the creation of the remote line mapping habitat
characterizations are available in previously filed technical memos (HDR Alaska, Inc. 2013a,
Appendix B).
4.1.1.2. Aerial Video Data Collection and Analysis
Low altitude aerial video was collected for the Upper River from PRM 187.1 to PRM 235.4, the
Middle River from PRM 102.4 to PRM 187.1, and a short section of the Lower River from PRM
68.0 to PRM 83.5. The study area for the tributary component of the 2012 Aerial Video Habitat
Mapping (HDR Alaska, Inc. 2013b, R2 Resource Consultants, Inc. 2013b) included 16 tributary
streams above Devils Canyon upstream to and including the Oshetna River. All tributaries
above Devils Canyon with documented Chinook salmon presence were included within the
videography study area (Tables 4.1-1 and 4.1-2).
Because habitat delineation was not always possible from remote imagery, a mesohabitat
frequency analysis was completed for a subset of habitat in 16 videotaped tributaries (Table 4.1-
1) using a systematic random sample of the video recording as described in the Study Plan (RSP
Section 9.9.5.3.1). Videography collected in the Upper and Middle River mainstem was used as
supplemental information in support of habitat characterization from remote imagery.
Aerial video was collected over a period of six days from September 7 to September 12, 2012
during optimal conditions that preceded a major flooding of the Susitna River in mid-September.
Videotaping of main channel and off-channel habitats of the Susitna River and tributaries was
scheduled in early September 2012 to coincide with late summer base-flow conditions, high
water clarity, leaf drop and the possibility of a sustained high pressure, clear weather window.
These conditions were achieved (HDR Alaska, Inc. 2013a).
Aerial video coverage within the study tributaries generally extended from the confluence with
the Susitna River, or with the primary tributary, upstream to an elevation of approximately 3,000
ft. In tributaries in the Upper River not known to support Chinook salmon, video mapping
terminated at approximately 2,200 ft elevation. For non-Chinook tributaries in the Middle River
above Devils Canyon, video mapping terminated at the first anadromous barrier. Devil Creek, a
Middle River tributary, was videotaped upstream to the impassable barrier at approximately RM
2.2.
Within each tributary reach, (as delineated in Section 4.1.2.1.2), mesohabitat frequency analysis
from video was used to identify primary mesohabitat types, defined as those comprising more
than 10 percent of the total frequency of mesohabitat types observed by reach (Table 4.1-3).
These primary mesohabitats were then used to set sampling targets for the 2013 ground-mapping
exercise within identified tributaries (Section 4.2.1).
Additional details of videography methods, analysis and interpretation are included in Appendix
2 of the Fish Distribution and Abundance Implementation Plan (HDR Alaska, Inc. 2013a);
detailed results are also available in Initial Results Aerial Video Habitat Mapping of Susitna
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River Tributaries from the Upper Extent of Devils Canyon to the Oshetna River (R2 Resource
Consultants, Inc. 2013b).
Overview of Ground Mapping Survey Protocols 4.1.2.
The intent of the ground mapping effort was to provide mesohabitat classifications in habitats
that were difficult to survey using remote line mapping methods (e.g. tributaries and off-channel
habitats), to provide detailed habitat characterization of Focus Areas, and to ground-truth a
random sample of macro and mesohabitat classifications from the remote line mapping database.
Field surveys used the same hierarchically-nested habitat typing system developed for use during
the remote line mapping exercise (Tables 1.1-1 and 1.1-2). This overview describes the general
methods applied to habitat mapping and surveys overall. River segment-specific variations in
methods are presented in Sections 4.2, 4.3, and 4.4 for the Upper River, Middle River and Lower
River, respectively.
4.1.2.1. Geomorphic Reach Delineation
4.1.2.1.1. Mainstem Susitna River
The Susitna River was categorized into Geomorphic Reaches as part of the Geomorphology
Study (Study 6.5) and consisted of six reaches for the Upper River Segment (UR-1 through UR-
6), eight reaches for the Middle River Segment (MR-1 through MR-8), and six reaches for the
Lower River Segment (LR-1 through LR-6) (Section 5.1.2 in ISR Study 6.5 and Figure 3-1).
The geomorphic reach breaks were based in part on the following five factors: 1) planform type
(single channel, island/side channel, braided); 2) confinement (approximate extent of floodplain,
off-channel features); 3) gradient; 4) bed material / geology; and 5) major river confluences.
4.1.2.1.2. Tributaries
Using desktop tools, including IFSAR topographic contour data, U.S. Geological Survey
(USGS) topographic maps, aerial video, and information from reconnaissance flights, tributaries
were segmented into geomorphic reaches. Reach breaks were identified using the following
criteria:
1. Gradient reach break: a significant transition in slope of valley or channel;
2. Confinement reach break: a significant transition in bankfull width:valley width or
wetted:bankfull width ratios;
3. Hydrologic reach break: a tributary confluence where the tributary appeared to contribute
more than 10 percent of total flow to the main channel or parent tributary. A segment
boundary was not placed where downstream channel characteristics were primarily
controlled by bedrock rather than fluvial processes.
4.1.2.2. Field Methods
Habitat metrics were collected using a modified U.S. Department of Agriculture, Forest Service
(USFS) Tier I through Tier III stream habitat survey protocol (USFS 2001). Some of the habitat
metrics listed in the USFS protocol assume that the stream being surveyed is wadeable; however,
many of the tributaries and mainstem habitat units selected for ground surveys were only
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wadeable along stream margins. Modifications were made to accommodate non-wadeable
stream reaches.
The following habitat metrics were collected for each selected tributary geomorphic reach, and
for each mainstem habitat unit:
Habitat Metrics
• Mesohabitat unit type (Tables 1.1-1 and 1.1-2)
• GPS location of channel measurements
• Measured or estimated gradient
• Measured unit length (range finder or remote using GIS)
• Measured or estimated bankfull width (BFW) (three measurements per unit)
• Measured average wetted width (three measurements per unit)
• Measured bankfull depth (BFD) of unit (three measurements per unit)
• Measured or estimated wetted maximum depth (thalweg) (three measurements per unit)
• Estimated percent substrate composition within wetted width of unit
• If pool, estimated or measured maximum depth
• If pool, estimated or measured pool crest depth
• If pool, identified structural feature forming the pool
• Large woody debris (LWD) count within wetted width of unit
• Estimated percent undercut, each bank in unit
• Estimated percent erosion, each bank in unit
• Type and percent in-stream cover in unit
• Estimated percent riparian vegetation cover in unit
• Dominant riparian vegetation type for each unit
• Photograph of each unit
Field surveys were conducted by two- or three-person survey crews. Each survey crew consisted
of a qualified lead biologist and field technician(s). To the extent possible, field surveys were
conducted at flows similar to those recorded during the capture of aerial video and reference
photographs (Figure 4.1-1).
Mainstem survey start and end points for the randomly selected macro- and mesohabitat units
were determined from GIS waypoints obtained from the GIS database prior to field efforts
commencing (Sections 4.2.2 and 4.3.2; Appendices C and D). Habitat units within mainstem and
tributary surveys were sequentially numbered as encountered from downstream to upstream.
Tributary ground survey start and end points were based on those detailed for video-mapping in
tributaries (section 4.1.1.2) but are simplified; there is no distinction between end points in
streams with or without Chinook presence. Accordingly, tributary ground survey reaches
originated in the lowest geomorphic reach of the tributary just upstream of the ordinary high
water line of the mainstem Susitna and progressed in an upstream direction. In Upper River
tributaries ground surveys ended at 3,000 ft or if a permanent impassable barrier was
encountered upstream of the 2,200-ft elevation point (Table 4.1-1). Permanent impassable
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barriers encountered downstream from the 2,200-ft elevation point were documented and barrier
measurements were taken. In Middle River tributaries above Devils Canyon, ground surveys
also ended at 3,000 ft or if a permanent impassable barrier was encountered, whichever came
first (Table 4.1-1); where permanent impassable barriers were encountered these were
documented and barrier measurements were taken and the survey continued. For tributary
surveys in the Middle River below Devils Canyon, surveys were conducted within the length of
stream within the zone of hydrologic influence of potential Project operations (Table 4.1-2).
When split or multiple split main channels were encountered in mainstem surveys, the channel
identified by the remote line was surveyed and the estimated percent of flow in that channel was
recorded. When split main channels were encountered in tributaries, both channels were
surveyed with the channel containing an estimated majority of flow categorized as primary, and
the other categorized as secondary. Mesohabitat units in the primary channel were categorized
as primary units and were numbered sequentially as part of the main tributary channel survey.
Mesohabitats within secondary channels were recorded separately. When multiple split main
channels were encountered in tributaries (more than two dominant channels), each channel was
photographed; however, only the primary and secondary channels were surveyed. Side channels
were identified as entering from the left (LB) or right bank (RB, looking downstream). The inlet
and outlet of each side channel was documented using waypoints, photographs, and descriptions.
The Susitna River mean daily discharge was obtained from the nearest downstream USGS
stream gage for each field survey date. In addition, relative flow levels in each mesohabitat on
the day of the survey were estimated using the following qualitative categories:
• Dry: No surface water visible,
• Puddled: Series of isolated pools connected by surface trickle or visible subsurface flow
(e.g., wetted substrates),
• Low Flow: Surface water flowing across 50 to 75 percent of the BFW,
• Moderate Flow: Surface water flowing across 75 to 90 percent of the BFW,
• High Flow: Stream flowing completely across BFW, but not at BFW.
4.1.2.3. Special Habitat Features
For 2013 field surveys, special habitat features were defined as tributaries, seeps, and springs
that contributed tributary or groundwater to the mainstem and temporary (e.g., subsurface flow,
perched debris jams, perched culverts) or permanent barriers to upstream fish migration.
Backwater habitats, beaver complexes and clearwater plumes were considered Level 3
macrohabitats during the development of the study plan and then were re-assigned as Level 4
mesohabitats (following the directive in the April 1, SPD). Backwaters, beaver complexes and
clearwater plumes were also treated as special habitat features and along with the features
described above, were specifically noted when encountered in the course of field survey efforts.
Additional data pertinent to these features (e.g. width of the feature in addition to channel wetted
width) were noted on field forms. A GPS waypoint was recorded and a photograph taken of
each special feature.
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For features classified as stream barriers only cursory information was collected under the
Habitat Mapping study, as most of the formalized barrier survey data are being collected under
the Fish Passage Barrier Study (ISR Study 9.12). The following information was recorded:
• Barrier type (beaver dam, debris dam, vertical falls, chute/cascade, boulder, other),
• Temporal nature (ephemeral or permanent),
• Maximum height of falls or biggest single step if cascading,
• Maximum depth of plunge pool,
• Chute/cascade gradient and length,
• Length of feature.
4.1.2.4. Mapping near reference flows
Flows in the Susitna River as measured at the Gold Creek gage were generally higher than those
recorded during videography and imagery used for remote line mapping although they were
within target upper flows established during operational planning to guide field efforts (Figure
4.1-1). Field surveys in 2013 were conducted in a roughly downstream to upstream manner
throughout the field season; flows during surveys in Middle River reaches were closer to target
or reference flows than the Upper River surveys conducted in the later portion of the field effort
(Figure 4.1-1).
4.2. Upper River Habitat Mapping
AEA implemented the methods as described in the Study Plan with the exception of the
variances described in Section 4.2.4. Following completion of the 2012 remote line mapping
effort (Section 4.1.1), field surveys were conducted to ground-truth Upper River habitat to the
mesohabitat level (Section 4.1.2). Due to the vast extent of the Upper River, sub-sampling
during ground-truthing was required. For 2013, surveys were initially planned for a total of 42
randomly selected mainstem macrohabitat units, 42 single main channel mesohabitat units, 25
tributaries within the proposed reservoir inundation zone, and three tributaries (two primary, one
secondary) located upstream of the inundation zone. The Upper River inundation zone
tributaries targeted for field surveying included 10 primary tributaries that were also selected for
fish distribution and abundance sampling and had been previously video surveyed (Section
4.1.1.2) and 15 additional small primary and secondary tributaries selected in response to the
FERC April 1 SPD and consultation with the TWG following review of the Technical
Memorandum: Characterization and Mapping of Aquatic Habitats (HDR 2013). The Upper
River tributaries selected and those surveyed during the 2013 field season are listed in Table 4.1-
1.
Tributaries in the Upper River 4.2.1.
4.2.1.1. Primary Tributaries
During 2012, select Upper River tributaries were mapped using a combination of low-altitude
aerial video (10 tributaries, Table 4.1-1) and limited on-the-ground field surveys in a subset of
those videographed tributaries (reaches of Watana Creek, Jay Creek and Kosina Creek). Details
of methods and the results of those 2012 preliminary field surveys were presented in 2012 Upper
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Susitna River Fish Distribution and Habitat Study – Habitat Report (HDR Alaska, Inc. 2013b).
These tributaries, together with additional tributaries that were not conducive to aerial video
mapping (Section 4.2.1.1) were ground surveyed during the 2013 field effort (Figure 4.1-2).
Continuous habitat surveys were conducted within each delineated geomorphic reach (Section
4.1.2.1.2) of each selected tributary. Habitat surveys were conducted over a distance equivalent
to at least 20 consecutive channel widths, with the goal of sampling at least five units of each of
the primary mesohabitat types occurring in the geomorphic reach. Primary mesohabitats were
determined from the video frequency analysis previously described (Table 4.1-3 and Section
4.1.1.2). The 20-channel-width section within each tributary geomorphic reach was selected
based on accessibility to multiple and varied mesohabitat types. Survey distance was extended,
either contiguously or at another location in the geomorphic reach, to ensure inclusion of five
replicates per primary habitat type. If accessible by foot or helicopter and within the 20 channel
width survey length, e.g. not in the bottom of a gorge, non-primary habitats were also surveyed
to the extent possible.
Access by helicopter or cross-country to points along the stream was problematic because many
tributaries were heavily forested. The starting and ending points for field surveys during 2013
were largely dependent on accessibility and could not be randomly selected. Many streams were
accessed by helicopter via a landing zone along the Susitna River near the mouth of the tributary.
In the lowest geomorphic reach of each primary tributary, surveyors started the mapping section
just upstream of the ordinary high water line of the mainstem Susitna River. Upstream
geomorphic reaches were surveyed if access and maneuverability within or along the stream was
determined to be safe. Safeness of landing zones was determined by the helicopter pilot.
Reasonableness of conducting the survey was determined by the field crew lead and was
dependent on the distance and difficulty of cross country travel from the helicopter landing zone
to the stream section to be mapped. Conditions preventing access were documented.
A total of 11 (of 13) primary or large tributaries have been fully or partially ground-surveyed and
mapped to the mesohabitat scale (Table 4.1-1).
4.2.1.2. Smaller and secondary tributaries within the Upper River inundation
zone
Most small tributaries in the Upper River inundation zone are obscured from overhead view due
to a closed canopy of riparian vegetation and thus were not mapped using aerial imagery.
Fifteen of these tributaries were added to those selected for ground-surveys in response to the
FERC April 1, 2013 SPD and consultation with the TWG (Table 4.1-1). Survey protocols for
these smaller tributaries are the same as those used in larger tributaries in the Upper River
(Section 4.2.1.1).
Mainstem habitats in the Upper River 4.2.2.
Upper River mainstem habitat was remote line-mapped using a hierarchically-nested habitat
typing methodology based on assessment of aerial still imagery, LiDAR, and aerial videography
as described in Section 4.1.1. Reaches UR-1 and UR-2 were classified solely as mainstem (main
channel, off-channel), or tributary habitat. UR-3 through UR-6 were classified to the
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mesohabitat level using the available remote imagery (Section 4.1.1.1) with supplemental
information provided from videography (Section 4.1.1.2).
Upper River field surveys were conducted in 2013 in accordance with the methods outlined in
Section 4.1.2. The random selection of habitat units for ground-truthing proceeded in two ways.
For single main channel habitat (which lacked obvious survey start and end points) seven units
of each mesohabitat type (or all if less than seven were available) were targeted at random for
ground-truthing of the remote line mapping mesohabitat call and collection of habitat metrics
(Section 4.1.2.2). In all other habitat types, macrohabitat length could be determined prior to the
field effort and so seven units (or all if less than seven available) of these mainstem macrohabitat
types (split main channel, multiple split main channel, side channel, tributary mouth, side slough,
upland slough) were targeted at random for ground-truthing of both macro and mesohabitat
(Level 3 and Level 4) and collection of habitat metrics. For the targeted upland and side sloughs,
the study teams attempted to locate at least two of each slough type that had an associated beaver
complex. Altogether, field surveys to ground-truth habitat that had been previously typed by
remote imagery were planned for a total of 42 single main channel mesohabitat units and 42
randomly selected mainstem macrohabitat units within the Upper River. However, the final
selection of habitat units was drawn from habitat units that both existed and were accessible;
thus, the pool of available habitats was less than the targeted selection and included only 21
available mesohabitats within single main channels and 27 macrohabitat units of other types
(Table 4.2-1).
Within single main channel macrohabitat, all targeted and existing mesohabitats were mapped
during the 2013 field effort (7 riffles, 7 run/glide units). Pools were not present within single
main channel habitats of the Upper River. While rapids did occur, the consensus of field crew
leaders and boat drivers was that these habitats could not be safely surveyed. Macrohabitat units
other than single main channel were selected to be surveyed to the extent that they were present
on the riverscape (Table 4.2-1). Multiple split main channel habitats and upland or side sloughs
with beaver influence could not be located within the Upper River. Among habitats that were
both targeted and available, field crews surveyed 6 of 7 split main channel units, 4 of 7 targeted
side sloughs and 3 of 6 targeted upland sloughs (Table 4.2-1). Field crews completed 6 of 7
targeted side channels noting that one of the selected side channels could not be surveyed due to
a dangerous rapid across the access point.
The special habitat features, including backwaters, beaver complexes and clearwater plumes,
were scarce in the Upper River, although clearwater plume habitat was present in UR-3 and UR-
4 (Appendix B). Only one backwater habitat was identified during the remote line mapping in
the Upper River. These mesohabitat units did not occur within single main channel habitat and,
thus, were not targeted during the random selection procedure.
Lakes within the Upper River Inundation Zone 4.2.3.
There are 12 lakes currently known to be within the zone of reservoir inundation, according to
the National Hydrography Database (NHD). These lakes were located, mapped, and identified in
the Project GIS database (Table 4.2-2); elevation, surface area, and perimeter, were calculated
and the presence or absence of surface water connection to the Susitna River was noted. The
lakes identified are shown by number in Figure 4.2-1 and in Table 4.2-2.
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Variances from the Study Plan 4.2.4.
AEA fully implemented the FERC approved study methods with the exception of the following
three variances.
4.2.4.1. Access Limitations
The Study Plan (RSP Sections 9.9.5.3.2 and 9.9.5.4) provided that AEA would characterize and
map a random subsample of main channel, off-channel and tributary habitats assuming full
access to the Susitna drainage basin. Additional selection of smaller and secondary tributaries
was discussed in the July 2013 technical memo Characterization and Mapping of Aquatic
Habitats (HDR 2013b). Instead AEA initiated surveys in 2013 to characterize and map a subset
of the initially randomly-selected habitats that were not located on Cook Inlet Regional Working
Group (CIRWG) lands. This access restriction, in addition to uncontrollable access limitations
due to high velocity water, rapids, canyons or other physical barriers, resulted in incomplete
spatial coverage and reduced sample sizes across Upper River mainstem and tributary habitats as
detailed below.
AEA will map and characterize all habitat units in both Upper River mainstem and selected
tributaries in the next study year to meet study objectives.
4.2.4.1.1. Mainstem Habitats
Restricted access to CIRWG lands constrained the total stream length sampled and a limited
number of mainstem habitats were judged unsafe due to safety considerations. However,
coverage of mainstem habitats selected was nearly complete. Mainstem units that could not be
sampled due to restricted CIRWG land access or safety concerns were approximately 8 percent
of the total planned in the Upper River (Table 4.2-1). The upstream and downstream boundaries
(as project river miles) of mainstem habitat that were inaccessible due to either CIRWG land or
safety considerations are provided in Table 4.2-3.
4.2.4.1.2. Tributaries
Approximately 18 percent of the tributary geomorphic reaches that were selected for ground
mapping had CIRWG land access restrictions; these are identified in Table 4.1-1. Certain
segments of selected Upper River tributaries were accessible for short distances that occurred on
public lands. In total, 3 tributaries were not surveyed (197.7, Watana Creek RB-1 and Watana
Creek LB 1.1.1) and 3 tributaries were partially surveyed (204.3-LB, 194.8-RB and Deadman
Creek) due to access limitations.
4.2.4.2. Special Habitat Features
The Study Plan Determination provided that backwater habitats, beaver complexes and
clearwater plumes be considered as Level 3 habitats (mesohabitats) under AEA’s nested
hierarchical classification scheme (SPD B-210; Table 1.1-1) and that backwater habitats be
identified and given specific consideration within the Study Plan (SPD B-212). Instead AEA
identified each of these as special habitat features (RSP Section 9.9.5.3.2.2) requiring additional
consideration. These three habitats were not nested hierarchically as other mesohabitats were,
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but rather tended to occur in association with a smaller subset of macrohabitat types (clearwater
plumes were typically associated with tributary mouths; beaver complexes and backwaters with
side or upland sloughs).
As special habitat features these were mapped using analogous methods to mesohabitat units but
with modifications to characterize the features of particular interest (e.g., width of the clearwater
plume was measured rather than the wetted width of the channel). By identifying these habitats
as special habitat features, AEA will better meet the study objectives of characterizing and
mapping habitats for the purposes of informing other studies, particularly the Upper River Fish
Distribution and Abundance Study (Study 9.5) since these are habitats of note for fishes. This
variance will also allow AEA to target these habitats for “specific consideration” as
recommended by FERC in the Study Plan Determination (SPD B-212).
During 2012 remote line mapping of the Upper River, clearwater plumes were rare and identified
only in UR-3 and UR-4 (HDR Alaska, Inc. 2013a, Appendix B); backwater habitats were also
rare and present only in UR-4 (Appendix B), whereas beaver complexes were not identified in
the Upper River. These habitats were not encountered during 2013 field surveys of randomly
selected macrohabitats in the Upper River. AEA did not specifically target these habitats in the
Upper River as they were not representative of mesohabitat characteristics in that segment of the
river. Extensive field surveys of each of these features have been conducted in the Middle River
both within and outside of Focus Areas (Section 4.3.3.2). This mapping effort in the Middle
River, where these features are more common, has allowed AEA to meet the objective of
considering these habitats as special mesohabitat features and giving backwater habitats in
particular “special consideration.”
4.2.4.3. Ground Survey Flow Conditions
The Study Plan (RSP Section 9.9.5.3.2) provided that ground mapping for Upper River
tributaries would be done at low to moderate flows similar to those which occurred during aerial
videography to allow for similar habitat calls for the two methods. Instead the study teams
mapped habitats in both tributaries and mainstem habitats during all windows of accessibility in
terms of both flow levels and weather conditions (Section 4.1.2.4); flow levels at the Gold Creek
gage during the 2013 field mapping season are shown in Figure 4.1-1.
This variance from the approved study methods was a consequence of unpredictable flow
throughout the season and could not be avoided even with careful planning. AEA realized that it
would be very difficult to map the large amount of habitat, particularly in the Middle River,
within the short time window where Susitna River flows were between the 10,000 and 12,000 cfs
(Figure 4.1-2). Accordingly, AEA prioritized mapping of habitats more likely to be altered by
high flow conditions. Side sloughs were given highest priority for low flow mapping in order to
minimize mapping during potential breaching flows; the target upper flow for mapping in side
sloughs was approximately 18,000 cfs. During the 2013 field effort, 19 side sloughs (out of 22)
were mapped at flows less than about 21,000 cfs; 3 side sloughs were mapped at a high flow of
30,700 cfs (Table 4.2-4). Main channel habitats were consistently mapped at flows less than
about 25,000 cfs with just under 20 percent of habitats mapped at higher flows up to a maximum
of 31,400 cfs (Table 4.2-4). Upland slough habitats were almost entirely mapped at flows less
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than 30,000 cfs with just three (of 29) upland sloughs mapped at a high flow of 31,400 cfs
(Table 4.2-4).
Determining whether ground-truthing at the range of flows encountered during field surveys in
2013 was adequate to meet the study objectives is dependent on the degree and magnitude of
difference in the resulting habitat calls. Preliminary examination of the data suggests that
although target flows were not universally achieved during ground surveys, conflicts between
remote-line mapping or videoed habitat calls and ground-survey habitat calls were infrequent.
The infrequency of these differences despite greater than planned for disparity in mapping flows
supports AEA’s belief that the objective of ground-truthing remote-line mapping habitat calls has
been met. Details of the degree of discrepancy will be presented in the Updated Study Report.
4.3. Middle River Habitat Mapping
AEA implemented the methods as described in the Study Plan with the exception of the
variances described in Section 4.3.3. As described in Section 4.1.2.1.1, the Middle River was
divided into eight geomorphic reaches. In 2012, remote line mapping was applied to the entire
Middle River segment as per the methods described in Section 4.1.1. In 2013, field surveys were
conducted in selected tributaries of the Middle River segment and in randomly selected
mainstem habitat units following the same selection procedure described for the Upper River
(Section 4.2.2; Table 4.2-1).
Tributaries in the Middle River 4.3.1.
Matanuska-Susitna Borough LiDAR and imagery were available for the lower extent of many
tributaries within the study area, however, overhanging vegetation, shadows and other
environmental conditions limited characterization of mesohabitats from these sources in 2012.
In higher elevations within tributaries, mesohabitat characterization was not possible from aerial
imagery due to lack of high resolution photography. Subsequently, a subset of seven tributaries
in the Middle River segment within or above Devils Canyon was selected for mesohabitat typing
by videography as described in Section 4.1.1.2 (Table 4.1-2).
A total of six tributaries outside of Focus Areas within and upstream of Devils Canyon in the
Middle River were selected for ground mapping in 2013 (Tsusena Creek, 184.0-RB, Fog Creek,
Devil Creek, Chinook Creek, Cheechako Creek). These tributaries were also among those that
were videographed in 2012. Two additional tributaries are located in FA-173 (Stephan Lake
Complex) in the Middle River above the lower extent of Devils Canyon. These tributaries were
divided into geomorphic reaches based on tributary basin drainage area and stream gradient
according to criteria described in Section 4.1.2.1.2. Three of these tributaries have been partially
ground-truthed (173.8-RB, Fog Creek, Chinook Creek). Habitat classifications within these
tributaries were ground-truthed according to the same methods described for Upper River
tributaries (Section 4.2.1).
An additional 20 tributaries that were known to contain populations of anadromous and resident
fishes were selected within the zone of hydrologic influence (ZHI) of the proposed Project below
Devils Canyon; nine occurred within Focus Areas and 11 were outside of Focus Areas. In 2013,
reaches that were within the zone of hydrologic influence in these tributaries were ground
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mapped following field protocols described in Section 4.2.1. Of the 11 tributaries outside of
Focus Areas selected for field survey in the Middle River segment below Devils Canyon, a total
of four tributaries have been fully or partially ground-surveyed and mapped to the mesohabitat
scale (Table 4.1-2). Four of the nine tributaries within Focus Areas below Devils Canyon have
been fully or partially ground-surveyed.
Mainstem Habitats in the Middle River 4.3.2.
In 2012, remote line mapping for the Middle River mainstem occurred in an identical fashion as
the Upper River mainstem habitats as described in Section 4.1.1. In addition to the remote
mapping, field surveys were conducted in 2013 in accordance with the methods outlined in
Section 4.1.2.
In 2013, nine of the 10 Focus Areas in the Middle River were ground-mapped to the mesohabitat
level. Due to lack of permission to access private lands, a limited number of habitat units within
portions of Focus Areas FA-128 (Slough 8A) and FA-173 (Stephan Lake Complex), and all of
FA-151 (Portage Creek), were not ground-truthed in 2013 (Table 4.3-1). The remotely-mapped
line segments were used as a starting point to guide field sampling and unmapped features were
added as encountered.
Outside of Focus Areas, Middle River mainstem habitat was ground-mapped by selecting a
random subset of remote line-mapped macro- and mesohabitats using the methods and selection
criteria described in Section 4.2.2. As in the Upper River, the pool of available and accessible
habitats was less than the targeted selection and included 23 mesohabitats within single main
channels and 35 units of other macrohabitat types. In addition, private lands limited AEA access
to some targeted habitat units. Planned versus available habitats and habitat units ground-
mapped in the Middle River mainstem during the 2013 field season are presented in Table 4.2-1.
In the SPD, FERC directed AEA to identify backwater habitat and give this feature specific
consideration (SPD B-212). The 10 Focus Areas included a diversity of side channels, side
sloughs, and tributary mouths, which often contained a variety of backwater habitats at off-
channel and tributary mouths in the Middle River. During 2013, aquatic habitat field surveys
included measurement and characterization of all backwater features within Middle River Focus
Areas. The 2-D habitat modeling effort being conducted in Focus Areas, as described in the ISR
for Study 8.5, will allow for habitat-flow relationships to be developed in Focus Areas by
macrohabitat and by select mesohabitat (e.g. backwaters). Clearwater plumes and beaver
complexes were treated in the same manner as in the Upper River (Sections 4.1.2.3 and 4.2.2).
Variances from the Study Plan 4.3.3.
AEA fully implemented the FERC approved study methods with the exception of the following
three variances.
4.3.3.1. Access Limitations
The Study Plan (RSP Sections 9.9.5.3.2 and 9.9.5.4) provided that AEA would characterize and
map a random subsample of mainstem and tributary habitats assuming full access to the Susitna
drainage basin. Additional selection of smaller and secondary tributaries was discussed in the
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July 2013 technical memo Characterization and Mapping of Aquatic Habitats (HDR 2013b).
Instead AEA initiated surveys in 2013 to characterize and map a subset of the initially randomly-
selected habitats that were not located on private lands. This restriction, in addition to access
limitations associated with sites deemed unsafe due to rapidly flowing water, canyons or other
physical barriers resulted in incomplete spatial coverage and reduced sample sizes across Middle
River mainstem and tributary habitats as detailed below.
AEA will map and characterize all targeted habitat units in both the Middle River mainstem and
selected tributaries in the next study year to meet study objectives.
4.3.3.1.1. Mainstem Habitats
Limited access to private lands constrained the total area sampled. However, survey coverage of
targeted mainstem habitats during 2013 field surveys was nearly complete. Targeted mainstem
units that could not be mapped due to restricted access comprised approximately 14 percent of
the total target in the Middle River; areas of the river where selected habitat units were not
mapped due to either restricted access to private lands or safety considerations are identified in
Table 4.2-3; the majority of these areas were located or only accessible either within Devils
Canyon throughout MR-4 or on CIRWG (dominantly above Devils Canyon) or ARRC lands
(dominantly below Devils Canyon).
4.3.3.1.2. Tributaries
Certain segments of Middle River tributaries dominantly on CIRWG lands were accessible for
short distances. Portions of 26 Middle River tributaries covering 32 tributary geomorphic
reaches were inaccessible to field crews (Table 4.1-2). Eleven of 14 or approximately 79 percent
of tributary geomorphic reaches (in 8 tributaries) above the lower extent of Devils Canyon were
located on CIRWG lands. Of these, Devil Creek, Chinook Creek and Cheechako Creek are
located within Devils Canyon and were not mapped due to safety considerations; these three
tributaries also run at least partially through CIRWG lands (Table 4.1-2).
Thirteen of the 20 tributaries (including those within Focus Areas) below Devils Canyon were
located on private lands or 65 percent of tributary geomorphic reaches below Devils Canyon.
Tributary geomorphic reaches that were targeted for ground mapping but could not be sampled
due to access or safety issues are shown in Table 4.1-2.
4.3.3.2. Special Habitat Features
The April 1, SPD provided that backwater habitats, beaver complexes and clearwater plumes be
considered as Level 3 habitats (mesohabitats) under AEA’s nested hierarchical classification
scheme (SPD B-210, Table 1.1-1) and that backwater habitats be identified and given specific
consideration within the Study Plan (SPD B-212). Instead AEA identified each of these as
special habitat features (RSP Section 9.9.5.3.2.2) requiring additional consideration. These three
habitats were not nested hierarchically as mesohabitats were, but rather tended to occur in
association with a smaller subset of macrohabitat types (clearwater plumes were typically
associated with tributary mouths; beaver complexes and backwaters with side or upland
sloughs). As special habitat features these were mapped using analogous methods to
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mesohabitat units but with modifications to capture the features of particular interest (e.g. width
of the plume was measured rather than the wetted width of the channel).
Special habitat features were mapped as they were encountered in field surveys during the 2013
mapping effort. A total of 20 backwater mesohabitats, 33 beaver complexes and 9 clearwater
plumes were identified in the Middle River. These habitats were not encountered during field
surveys of randomly selected macrohabitat units in the Middle River. Although these habitats
were not targeted by the random selection protocol implemented during 2013, by identifying
these habitats as special habitat features, AEA will better meet the study objectives of
characterizing and mapping habitats for the purposes of informing other studies, particularly the
Study of Fish Distribution and Abundance in the Middle and Lower Susitna River (ISR Study
9.6) since clearwater plumes, beaver complexes and backwaters are habitats of note for fish.
This variance will further allow AEA to target these habitats for “specific consideration” as
recommended in FERC’s April 1 SPD (SPD B-212).
4.3.3.3. Ground Survey Flow Conditions
The Study Plan (RSP Section 9.9.5.3.2) provided that ground mapping for Upper River
tributaries would be done at low to moderate flows similar to those which occurred during aerial
videography to allow for similar habitat classification from the two methods. Instead study
teams mapped habitats in both tributaries and mainstem habitats during all windows of
accessibility in terms of both flow levels and weather conditions (Section 4.1.2.4); flow levels at
the Gold Creek gage during the 2013 field mapping season are shown in Figure 4.1-1.
This variance from the proposed study methods was a consequence of unpredictable flow
throughout the season that could not have been avoided even with careful planning. AEA
realized that it would be very difficult to map the large amount of habitat, particularly in the
Middle River, within the short time window where Susitna River flows were between 10,000 and
12,000 cfs (Figure 4.1-1). AEA prioritized mapping of habitats more likely to be altered by high
flow conditions. Side sloughs were prioritized for low flow mapping in order to minimize
mapping during potential breaching flows; the target upper flow for mapping in side sloughs was
approximately 18,000 cfs. During the 2013 field effort, 19 side sloughs (of 22) were mapped at
flows less than approximately 21,000 cfs; 3 side sloughs were mapped at a high flow of 30,700
cfs (Table 4.2-3). Main channel habitats were prioritized for mapping at flows below 25,000 cfs
and were consistently mapped at this discharge level with just under 20 percent of habitats
mapped at higher flows up to a maximum of 31,400 cfs (Table 4.2-3). Upland slough habitats
were considered lowest priority for low flow mapping and were to be mapped under flow
conditions of 30,000 cfs or less; these were almost entirely mapped to this criteria with just 3 (of
29) upland sloughs mapped at a high flow of 31,400 cfs (Table 4.2-3).
Determining whether ground-mapping at the range of flows encountered during field surveys in
2013 was adequate to meet the study objectives is dependent on the degree and magnitude of
difference in the resulting habitat classification. Preliminary examination of the data suggest that
although target flows were not universally achieved during field surveys, conflicts between
remote-line mapping or videoed habitat classification and ground survey habitat classification
were infrequent. The infrequency of these differences despite greater than planned for disparity
in mapping flows supports the belief that the study goal of ground-truthing remote-line mapping
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habitat calls to meet the objective of characterizing habitats has been met. Details of the degree
of discrepancy will be presented in meetings of the TWG and in the Updated Study Report.
4.4. Lower River Habitat Mapping
AEA implemented the methods as described in the Study Plan with no variances. The
Geomorphology Study (Study 6.5, see RSP section 6.5.4.4.2.2) used existing LiDAR and aerial
imagery from the Matanuska-Susitna Borough LiDAR and Imagery Project to map the Lower
River. The Reconnaissance-Level Geomorphic and Aquatic Habitat Assessment of Potential
Effects on the Lower River Study (HDR Alaska, Inc. 2013b) was used to delineate different
geomorphic features in the mainstem Lower Susitna River. As part of that study, aerial
photographs from the 1980s and 2012 were reviewed to delineate all geomorphic features within
the Lower River floodplain. The habitat classification definitions followed those employed by
Ashton and Trihey (1985), and included main channel, side channel, bar islands, side sloughs,
upland sloughs, tributary channels, tributary mouths, tributary deltas and additional open water
areas.
As described in the Study Plan (RSP 9.9.5.4.3), it was impractical to map the entire river
segment beyond Level 3 (macrohabitat) because of the very large size and channel complexity of
the Lower River (Figure 4.4-1). The result of the test videography completed for a short segment
of the Lower River showed that a height of 400 ft or lower with three to five flight paths would
be necessary to visually differentiate mesohabitat types in the Lower Susitna River segment.
Further, several parallel paths would be extremely difficult to track even with the use of GPS and
would be very difficult to follow during review of the video. In summary, the review of the test
section concluded that aerial videotaping was not a practical method for habitat mapping the
Lower River.
5. RESULTS
This section of the ISR provides a detailed description of the results of the Study Plan to date by
major river segment. Within each river segment the outcomes of both remote line mapping and
ground surveys in both mainstem and tributary habitats are provided.
5.1. Upper River
The results of both remote line mapping and ground surveys in mainstem habitat units, tributary
reaches and lakes within the Upper River inundation zone are described in this section using a
combination of habitat distribution and frequencies. Results include a broad overview of average
habitat metrics within each mesohabitat unit type and for these metrics grouped by macrohabitat
designation. Macrohabitat summaries represent the average of habitat metrics in all surveyed
mesohabitats within that macrohabitat type and as such represent a subset of the average
conditions that may be present across an entire macrohabitat type.
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Tributaries in the Upper River 5.1.1.
The results presented for tributaries in the Upper River include information previously
summarized in technical memorandum for remote line mapping (HDR 2013b, R2 Resource
Consultants, Inc. 2013b, Appendix B); summaries of habitat distributions and metrics from
ground surveys conducted during 2012 (HDR Alaska, Inc. 2013b); and results from ground
surveys conducted during 2013, the most recent year of study.
5.1.1.1. Habitat Distribution from Remote Line Mapping (Aerial and Video)
Preliminary tributary geomorphic reach classes were established using aerial video and contour
maps. Additional information will be reviewed (e.g., aerial photos, habitat mapping photos, and
data collected during 2013 fisheries studies and ground-truthing habitat surveys) and used in the
final designation of the reach types to be reported in the Updated Study Report. For this reason,
the classification of type and the number of geomorphic reaches is considered preliminary.
The primary product of video mapping was a mesohabitat frequency estimate for the selected
tributaries. The results of the habitat frequency analysis from videography for selected Upper
River tributaries are summarized in Table 4.1-3; additional details were presented in Appendix 2
of the Fish Distribution and Abundance Implementation Plan (R2 Resource Consultants, Inc.
2013b). Results are presented by study area tributary and include mesohabitat frequency
analysis, distribution of mesohabitat types by river mile and tributary geomorphic reach; and
photographs that provide a visual reference of some of the more prominent habitat types and the
general character of each tributary (R2 Resource Consultants, Inc. 2013b).
5.1.1.2. Habitat Distribution from Ground Surveys
During 2012, preliminary ground-mapping was conducted in several reaches of Jay, Kosina and
Watana creeks. The relative frequency of each mesohabitat unit type based on length was
calculated. Details and summary statistics for mesohabitat units within this preliminary effort
were presented in 2012 Upper Susitna River Fish Distribution and Habitat Study: Habitat
Report (HDR Alaska, Inc. 2013b). Overall, the mesohabitat type composition between main
channels and side channels in these three tributaries appeared to be driven by the different
hydrologic regimes as would be expected within the two channel types. Main tributary channels
were dominated by riffle and run mesohabitats whereas tributary side channels contained a
greater diversity of mesohabitat types (HDR Alaska, Inc. 2013b).
During the 2013 ground survey effort, a total of 11 tributaries that had been mesohabitat mapped
using videography (Section 4.1.1.2) were ground-mapped to the mesohabitat level (Table 4.1-1).
The total length surveyed within these Upper River tributaries during 2013 was 32,753 m (20.4
mi) with an average survey length of 1,170 m (0.73 mi) within each tributary geomorphic reach
(Table 5.1-1). A comparison of mesohabitat characterization from those field surveys against
habitat classifications made using 2012 remote line mapping and videography will be presented
in the Updated Study Report.
Mesohabitats in these tributaries were largely composed of boulder riffle, riffle, and run
mesohabitats representing 27 percent, 22 percent, and 20 percent of the total length of tributary
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habitat surveyed respectively (Table 5.1-1). Descriptive summary statistics for select habitat
metrics by mesohabitat within Upper River tributaries surveyed during the 2013 field effort are
presented in Tables 5.1-2 through 5.1-6. Data for all habitat metrics will be comprehensively
summarized in the Updated Study Report.
Average habitat characteristics included mean gradients (outside of alcoves, beaver ponds and
percolation channels) ranging from 0.2 percent in pools to 8.9 percent in cascades. Overall mean
bankfull width in all mesohabitats surveyed was 21 m (23 yd) with a range from 1 m (1.1 yd) in
alcoves to 27 m (29.5 yd) in riffles; overall mean wetted width was 18 m and ranged from 1 m
(1.1 yd) in alcoves to 24 m (26.3 yd) in glide and riffle mesohabitats. Overall mean bankfull
depth was 0.9 m (1 yd ) and ranged from 0.4 m (1.3 ft) in alcoves to 1.4 m (1.5 yd) in pool
mesohabitats; overall mean thalweg depth was 0.7 m (2.3 ft) and ranged from 0.2 m (0.7 ft) in
percolation channels to 0.9 m (1 yd) in beaver ponds, glides and pool mesohabitats.
Mainstem Habitats in the Upper River 5.1.2.
The results presented below for mainstem habitats in the Upper River include information
previously summarized in technical memoranda for remote line mapping (HDR 2013b, R2
Resource Consultants, Inc. 2013b, Appendix B); summaries of habitat distributions and metrics
from ground surveys conducted during 2012 (HDR Alaska, Inc. 2013b); and results from ground
surveys conducted during 2013, the most recent year of study.
5.1.2.1. Habitat Distribution from Remote Line Mapping (Aerial and Video)
An assessment of the remote line-mapping habitat characterization through videography in the
Upper River indicated that channel type was similar across geomorphic reaches. Approximately
70 percent of the riverine habitat was classified as main channel, 0 to 11 percent as off-channel
habitat, and roughly 25 percent as lower reaches of tributaries (Appendix B). Detailed methods,
analysis and results from the 2012 remote line mapping exercise in the Upper River are
presented in the technical memorandum Upper Susitna River Segment Remote Line Habitat
Mapping (Appendix B).
5.1.2.2. Habitat Distribution from Ground Surveys
The total length of macrohabitat surveyed within the Upper River mainstem during 2013 was
6,011 m (3.7 mi) composed of 842 m (0.52 mi) of split main channel, 64 m (0.4 mi) of multiple
split main channel, and 2,651 m (1.65 mi) of side channel (Table 4.2-1). Total lengths for habitat
characterized as a single main channel was not recorded on field forms; these unit lengths will be
determined from survey waypoints, assessed using GIS and presented in the Updated Study
Report. Excluding single main channel, the most common Upper River mainstem habitat was
side channel which represented 44 percent of the total measured habitat by length (Table 5.1-7).
Descriptive statistics for select habitat metrics summarized by macrohabitat within Upper River
mainstem habitat units surveyed during the 2013 field effort are presented in Tables 5.1-8
through 5.1-12. Data for all habitat metrics will be comprehensively summarized in the Updated
Study Report. Gradient was lowest in side slough macrohabitats with a mean gradient of 0.4
percent and was highest in multiple split main channels where the mean gradient was 2.0
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percent. Bankfull width ranged from 7 m (7.7 yd) in upland sloughs to 177 m (193.6 yd) in
single main channels; wetted widths ranged from 6 m (6.6 yd) in upland sloughs to 159 m (173.9
yd) in single main channel. Average thalweg depth ranged from 0.4 m (1.3 ft) in side sloughs to
3.4 m (3.7 yd) in single main channel; bankfull depth averaged 0.5 m (1.6 ft) in side sloughs and
2.4 m (2.6 yd) in single main channel macrohabitat.
Mesohabitat in the Upper River mainstem was largely composed of riffle, run, and glide habitats
which formed 29 percent, 25 percent, and 23 percent respectively of the total length of habitat
surveyed (Table 5.1-13). Backwaters, clearwater plumes and beaver complexes were not
encountered during mainstem surveys in the Upper River. Descriptive statistics for select habitat
metrics summarized by mesohabitat within Upper River mainstem habitat units surveyed during
the 2013 field effort are presented in Tables 5.1-14 through 5.1-18. Average habitat
characteristics (excluding values for dry mesohabitat) included mean gradient ranging from 0.1
percent in pool mesohabitat to 1.8 percent in riffle mesohabitat. Bankfull width ranged from 8 m
(8.7 yd) in pools to 131 m (143 yd) in run mesohabitat; wetted widths ranged from 8 m (8.7 yd)
in pools to 110 m (120.3 yd) in run mesohabitat. Average thalweg depth ranged from 0.7 m (2.3
ft) in glides to 2.5 m (8.2 ft) in run mesohabitat; average bankfull depth ranged between 0.7 m
(2.3 ft) in glide and 1.8 m (5.9 ft) in run mesohabitat.
Lakes Within the Upper River Inundation Zone 5.1.3.
Elevations of the 12 lakes within the Project inundation zone ranged from 487 m (1,598 ft) to
622 m (2,042 ft), the average perimeter and area were 623 m (2,043 ft) and 2.78 hectares (6.87
acres) respectively. Five lakes had a surface water connection to the Susitna River visible from
the GIS layer (Table 4.2-2). Additional habitat parameters will be collected during the next year
of study.
5.2. Middle River
The results of both remote line mapping and ground surveys in mainstem habitat units and
tributary reaches within the Middle River are described in this section using a combination of
habitat distribution and frequencies. Results include a broad overview of average habitat metrics
within each mesohabitat unit type and grouped by macrohabitat classification. Macrohabitat
summaries represent the average of habitat metrics in surveyed mesohabitats within that
macrohabitat type and as such represent a subset of the average conditions that may be present
across an entire macrohabitat type.
Tributaries in the Middle River 5.2.1.
The results presented for tributaries in the Middle River include information previously
summarized in technical memorandum for remote line mapping (HDR 2013b, R2 Resource
Consultants, Inc. 2013a, b, HDR Alaska, Inc. 2013a) and results from ground surveys conducted
during 2013, the most recent year of study.
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5.2.1.1. Habitat Distribution from Remote Line Mapping (Aerial and Video)
Preliminary geomorphic classes and the results of mesohabitat frequency analysis for
videography within Middle River segment tributaries upstream of Devils Canyon are
summarized in Table 4.1-3 and further detailed in Appendix 2 of the Fish Distribution and
Abundance Implementation Plan (R2 Resource Consultants, Inc. 2013b). Results are presented
by study area tributary and include mesohabitat frequency analysis, distribution of mesohabitat
types by river mile and tributary geomorphic reach; and photographs providing a visual reference
of some of the more prominent habitat types and the general character of each tributary.
5.2.1.2. Habitat Distribution from Ground Surveys
During the 2013 field effort, habitat surveys were conducted in eight Middle River tributaries;
three of these were above Devils Canyon and were surveyed in the manner of Upper River
tributaries (Section 4.1.2) and five tributaries were below Devils Canyon and were surveyed only
within the zone of hydrologic influence (ZHI) (Section 4.3.1) during the 2013 field effort (Table
4.1-2). These surveys included two Middle River tributaries that were also mesohabitat mapped
using videography during 2012 (Section 4.1.1.2) (Fog Creek and Chinook Creek, Table 4.1-2).
The average length of geomorphic reach surveyed was 849 m (0.53 mi) and a total of 7,488 m
(4.65 mi) were surveyed within these Middle River tributaries during 2013 (Table 5.1-1). A
comparison of mesohabitat characterization from field surveys in videographed tributaries
against habitat classifications made using 2012 remote line mapping and videography will be
presented in the Updated Study Report.
Overall mesohabitats in these Middle River tributaries were largely composed of boulder riffle,
riffle, and pool mesohabitats representing 22 percent, 21 percent, and 18 percent of the total
length of tributary habitat surveyed respectively (Table 5.1-1). Descriptive summary statistics
for select habitat metrics by mesohabitat within Middle River tributaries surveyed during the
2013 field effort are presented in Tables 5.1-2 through 5.1-6. Data for all habitat metrics will be
comprehensively summarized in the Updated Study Report.
Average habitat characteristics included mean gradients (outside of alcove and beaver pond
mesohabitats which had a mean gradient of 0 percent) ranging from 0.5 percent in glides to 4.4
percent in cascade mesohabitats, the overall mean gradient in these tributaries was 1.7 percent.
Overall mean bankfull width in all mesohabitats surveyed was 10 m (10.9 yd) with a range from
3 m (3.3 yd) in both alcove and percolation channel mesohabitats to 17 m (18.6 yd) in run
mesohabitats. Overall mean wetted width was 6 m (6.6 yd) and ranged from 2 m (2.2 yd) in
alcove and percolation channel mesohabitats to 8 m (8.8 yd) in cascade mesohabitats. The
overall mean bankfull depth was 0.7 m (2.3 ft) and ranged from 0.3 m (1 ft) in percolation
channels to 0.9 m (1 yd) in pool mesohabitats; overall mean thalweg depth was 0.5 m (1.6 ft) and
ranged from 0.1 m (0.3 ft) in percolation channels to 0.7 m (2.3 ft) in cascade mesohabitats.
Mainstem Habitats in the Middle River 5.2.2.
The results presented for mainstem habitat in the Middle River include information previously
summarized in technical memoranda for remote line mapping (R2 Resource Consultants, Inc.
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2013a, HDR Alaska, Inc. 2013a) and results from ground surveys conducted during 2013, the
most recent year of study.
5.2.2.1. Habitat Distribution from Remote Line Mapping (Aerial and Video)
Analysis of macrohabitat distribution from the 2012 remote line mapping indicated that
mainstem habitat varied by geomorphic reach and generally increased in complexity from
upstream to downstream locations (HDR Alaska, Inc. 2013a). Single main channel represented
the majority of habitat from the proposed dam site (MR-1) through Devils Canyon (MR-5).
Downstream of Devils Canyon (i.e., MR-6 to MR-8), channel types were broadly distributed
across channel categories; single main channel habitat was not the majority in any of those
reaches. Downstream reaches contained multiple split main channel habitat and many side
channels.
Mesohabitats in the main channel assessed from the 2012 remote line mapping were generally
dominated by a mixture of run and glide habitats. Clearwater plume habitats were located in
reaches MR-2, MR-3, MR-5, and MR-7, with the most being in reach MR-2; beaver dams were
rarely present in side slough habitat, and slightly more prevalent in upland sloughs and were only
observed in reaches MR-6 and MR-7. Backwater habitat was also relatively rare and primarily
present in the lower reaches from MR-6 through MR-8. Additional details of methods, analysis
and results of macrohabitat distribution assessed during 2012 remote line mapping are presented
in Middle Susitna River Segment Remote Line Habitat Mapping Technical Memorandum (HDR
Alaska, Inc. 2013a).
5.2.2.2. Habitat Distribution from Ground Surveys
The total length of macrohabitat units surveyed within the Middle River mainstem during 2013
both inside and outside Focus Areas (FAs) was 42,554 m (26.4 mi). This was composed of
2,708 m (1.68 mi) of single main channels, 3,511 m (2.18 mi) of split main channel, 3,982 m
(2.47 mi) of multiple split main channels, 11,404 m (7.09 mi) of side channels, 6,178 m (3.84
mi) of upland sloughs, and 203 m (0.13 mi) of tributary mouth habitat (Table 5.1-7). Total
lengths for some macrohabitat units were not recorded on field forms; these unit lengths will be
determined from survey waypoints, assessed using GIS and presented in the Updated Study
Report. The most common Middle River mainstem macrohabitat outside of Focus Areas was
multi-split main channel which represented 22 percent of the total measured habitat by length
(Table 5.1-7).
Descriptive statistics for select habitat metrics summarized by macrohabitat within all Middle
River mainstem habitat units surveyed during the 2013 field effort are presented in Tables 5.1-8
through 5.1-12. Outside of Focus Areas, gradient was lowest in upland sloughs where the mean
gradient was 0.0 percent whereas gradient was highest in side channel macrohabitat where the
mean gradient was 0.8 percent. Bankfull widths ranged from 12 m (13.1 yd) in upland slough to
179 m (195.8 yd) in single main channel. Wetted widths ranged from 5 m (5.5 yd) in upland
slough macrohabitat to 179 m (195.8 yd) in single main channel. The average thalweg depth
ranged from 0.3 m (1 ft) in upland slough macrohabitat to 2.5 m (8.2 ft) in single main channels;
average bankfull depths ranged from 0.9 m (3 ft) in side slough macrohabitat to 2.3 m (7.5 ft) in
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single main channel macrohabitat. Data for all habitat metrics averaged for each macrohabitat
type will be comprehensively summarized in the Updated Study Report.
Outside of Focus Areas, field surveyed mesohabitats in the Middle River mainstem consisted
dominantly of run habitat which formed 34 percent of the total length of habitat surveyed (Table
5.1-13). A total of 3 backwater mesohabitats were identified and these formed just 2 percent of
the total length of habitat surveyed in the Middle River segment. A total of 3 beaver complexes
and 1 clearwater plumes were identified. A comparison of mesohabitat characterization from
field surveys to habitat classifications made during remote line mapping and videography will be
presented in the Updated Study Report.
Descriptive statistics for select habitat metrics summarized by mesohabitat within Middle River
mainstem habitat units surveyed during the 2013 field effort (excluding Focus Areas) are
presented in Tables 5.1-14 through 5.1-18. Data for all habitat metrics will be comprehensively
summarized in the Updated Study Report. Average habitat characteristics (excluding values
from dry habitats) included mean gradients ranging from 0 percent in pool mesohabitat to 1.2
percent in riffle mesohabitat. Bankfull widths ranged from 17 m (18.6 yd) in pools to 152 m
(166.2 yd) in run habitats; wetted widths ranged from 7 m (7.7 yd) for pool mesohabitats to 118
m (129.1 yd) in run mesohabitats. The average thalweg depth ranged from 0.4 m (1.3 ft) in pools
to 1.8 m (5.0 ft) in run mesohabitats; average bankfull depths ranged between 1.0 m (3.3 ft) in
pools and 1.8 m (5.9 ft) in run mesohabitats.
Habitat metrics collected in Focus Areas were generally similar to those in non-Focus Areas.
Within Focus Areas, ground-surveyed macrohabitats consisted primarily of side channel and side
slough habitats which formed 38 percent and 25 percent by length respectively of the total length
of habitat surveyed. Select habitat metrics summarized by macrohabitat with Focus Area
included mean gradients ranging from 0.3 percent in single main channel to 1.0 percent in
tributary mouth. Bankfull width ranged from 9 m (9.8 yd) in upland slough to 181 m (198 yd) in
single main channel; wetted widths ranged from 6 m (6.6 yd) in both upland slough and tributary
mouth to 116 m (126.9 yd) in single main channel. Average thalweg depth ranged from 0.3 m
(0.98 ft) in tributary mouths to 1.6 m (5.2 ft) in single main channel; average bankfull depths
ranged between 0.6 m (1.97 ft) in tributary mouths and 2.0 m (6.6 ft) in single main channel
channels.
For Focus Areas alone, ground-surveyed mesohabitats (Tables 5.1-13 through 5.1-18), consisted
primarily of pool, riffle, and glide habitats which formed 22 percent, 22 percent, and 17 percent
respectively of the total length of habitat surveyed. Select habitat characteristics included mean
gradient ranging from 0.1 percent in pool to 1.3 percent in riffle mesohabitats. Bankfull width
ranged from 21 m (23 yd) in pools to 98 m (107.2 yd) in runs; wetted widths ranged from 12m
(13.1 yd) in pool to 85 m (93 yd) in run mesohabitat. Average thalweg depth ranged from 0.5 m
(1.6 ft) in pools and riffles to 1.3 m (4.3 ft) in run mesohabitats; average bankfull depth ranged
between 0.9 m (3 ft) in pools and 1.7 m (5.6 ft) in run mesohabitat. Backwaters, beaver
complexes and clearwater plumes respectively averaged 26 m (28.4 yd), 17 m (18.6 yd) and 185
m (202 yd) in bankfull width; 13 m (42.7 yd), 9 m (9.8 yd), and 3 m (3.3 yd) in wetted width; 0.5
m (1.6 ft), 0.8 m (2.6 ft) and 0.2 m (0.7 ft) in thalweg depth; and 1.0 m (3.3 ft), 1.3 m (4.3 ft) and
0.8 m (2.6 ft) in bankfull depth.
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A total of 17 backwaters were identified and these formed 6 percent of the total length of habitat
surveyed within Focus Areas; 20 beaver complexes and 7 clearwater plumes were identified
within Focus Areas (Table 5.1-13).
5.3. Lower River
Results from the 2012 video imagery confirmed that the Lower River appeared to contain only
two mesohabitat types (glides and riffles; Table 4.4-3 in R2 Resource Consultants, Inc. 2013b).
The low gradient and aggraded gravel bed of the Lower River was generally not conducive to the
formation of other mesohabitat types such as pools or runs, although they may have been present
in very low numbers. The review of the test section flown for videography during 2012
concluded that aerial videotaping was not a practical method for habitat mapping the Lower
River (R2 Resource Consultants 2013b); field surveys in this area would be prohibitively costly
and logistically complex.
6. DISCUSSION
This study was conducted to characterize and map aquatic habitat at finer scales than did the
1980s studies, including to the mesohabitat level in both mainstem and tributary habitats. The
initial results of the remote line mapping and videography components of the study provide an
index of the frequency and proportion of mainstem and tributary habitats within the Upper and
Middle Susitna River segments. The resolution of the data varied based on the size and visibility
of each habitat unit and relied upon the professional interpretation of biologists, nonetheless this
provided a tool that allowed informed decisions and planning for representing the Middle River
for instream flow (ISR Study 8.5) and fish distribution studies (ISR Studies 9.5 and 9.6) during
2013 and a basis for developing a survey protocol for field confirmation of habitat calls.
The completion of remote line mapping and interpretation of videography represented only a
small portion of habitat mapping study activity for 2013. Significant on-the-ground activity was
conducted in 2013 that expanded the resolution and working knowledge of available habitat in
the Susitna River and surrounding tributaries. Further details of those efforts will be combined
with the next study season’s field efforts to provide a complete and ground-truthed
representation of the macro- and meso-habitat distribution and character of the Susitna River in
the Updated Study Report.
6.1. Study Coordination and Updates
Multiple studies collected field data in 2013 to better refine habitat mapping databases. For
example, the Fish Distribution and Abundance Studies (ISR Study 9.5 and 9.6) collected limited
amounts of habitat data at fish sampling sites, and Geomorphology studies (ISR Studies 6.5 and
6.6) mapped Focus Areas. A GIS analysis is ongoing to map and compare mesohabitat calls
collected by the fish and habitat crews.
As described in the ISR for Study 8.5, the 2-D model framework developed for the Instream
Flow Study will model all off-channel and tributary confluences where backwater habitats are
generally formed – no further directed sampling of this habitat type is proposed. The data on
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backwater habitats generated by the 100 percent coverage of Focus Areas during ground surveys
will be used in the Fish and Aquatics Instream Flow Study (ISR Study 8.5) to specifically
include these habitat types in Middle River Focus Area 2D modeling.
7. COMPLETING THE STUDY
[As explained in the cover letter to this draft ISR, AEA’s plan for completing this study will be
included in the final ISR filed with FERC on June 3, 2014.]
8. LITERATURE CITED
Alaska Department of Fish and Game (ADF&G). 1983. Su Hydro draft basic data report, volume
4, part 1. ADF&G Su Hydro Aquatic Studies Program, Anchorage, Alaska.
Alaska Energy Authority AEA. 2012a. Revised Study Plan: Susitna-Watana Hydroelectric
Project FERC Project No. 14241. December 2012. Prepared for the Federal Energy
Regulatory Commission by the Alaska Energy Authority, Anchorage, Alaska.
http://www.susitna-watanahydro.org/study-plan.
Ashton, W.W., and E.W. Trihey. 1985. Assessment of Access by Spawning Salmon into
Tributaries of the Lower Susitna River. R&M Associates and E.W. Trihey and
Associates, Final Report to Alaska Power Authority. 66 pp.
Federal Energy Regulatory Commission (FERC). Office of Energy Projects. 2013. April 01,
2013. Study Plan Determination for the Susitna-Watana Hydroelectric Project No 14241-
000.
HDR. 2013. Characterization and Mapping of Aquatic Habitats Technical Memorandum:
Susitna-Watana Hydroelectric Project FERC Project No. 14241. July 2013.
http://www.susitna-watanahydro.org/wp-
content/uploads/2013/09/TechMemoCharacterizationMappingOfAquaticHabitats.pdf
HDR Alaska, Inc. 2013a. Middle Susitna River Segment Remote Line Habitat Mapping
Memorandum: Susitna-Watana Hydroelectric Project FERC Project No. 14241. January
2013.
HDR Alaska Inc, 2013b. 2012 Upper River Susitna River Fish Distribution and Habitat Study –
Habitat Report: Susitna-Watana Hydroelectric Project FERC Project No. 14241.
February 2013. http://www.arlis.org/docs/vol1/Susitna2/1/SuWa189.pdf
Moore, K.M.S., K.K. Jones, and J.M. Dambacher. 2006. Aquatic Inventories Project: Methods
for Stream Habitat Surveys. Oregon Department of Fish and Wildlife, Corvallis, Oregon.
R2 Resource Consultants, Inc. 2013a. Technical Memorandum: Adjustments to Middle River
Focus Areas: Susitna-Watana Hydroelectric Project FERC Project No. 14241. May 2013.
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http://www.susitna-watanahydro.org/wp-content/uploads/2013/05/SuWa_R2_TM-
FocusAreasAdjustments.pdf
R2 Resource Consultants, Inc. 2013b. Susitna River Fish Distribution and Abundance
Implementation Plan: Susitna-Watana Hydroelectric Project FERC Project No. 14241.
March 31, 2013 including HDR prepared Appendix 2, Initial Results Aerial Video
Habitat Mapping of Susitna River Tributaries from the Upper Extent of Devils Canyon to
the Oshetna River, January 2013. http://www.susitna-watanahydro.org/wp-
content/uploads/2013/09/SuWa-FSP-2013-Section-09.05-FDAUP.pdf
Trihey, E.W. 1982. Preliminary assessment of access by spawning salmon to side slough habitat
above Talkeetna. Susitna Hydroelectric Project Doc. No. 134. 24 pp.
U.S. Forest Service (USFS). 2001. Chapter 20 – Fish and Aquatic Stream Habitat Survey. FSH
2090-Aquatic Habitat Management Handbook (R-10 Amendment 2090.21-2001-1).
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9. TABLES
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Table 1.1-1. Nested and tiered habitat mapping units and categories for macrohabitats and mainstem channel mesohabitats.
Level Unit Grouping Category Definitions
1
Major
Hydrologic
Segment
Segments
Upper,
Middle, Lower
River
Upper River – PRM –187.1 – 261.3 (habitat mapping extended up to mainstem PRM 235.1 and included the Oshetna
River.
Middle River - PRM –102.4 – 187.1
Lower River - PRM 0 – 102.4
2 Geomorphic
Reach
Upper River
Segment 6 reaches
Middle River
Segment 8 reaches Geomorphic reaches that uniquely divide the Major Hydrologic Segments based on geomorphic characteristics.
Lower River
Segment1 6 reaches
3 Macrohabitat
Main
Channel
Habitat
Single Main
Channel
Single dominant main channel.
Split Main
Channel
Two dominant channels.
Multiple Split
Main Channel
Three or more distributed dominant channels.
Side Channel Channel that is turbid and connected to the active main channel but represents non-dominant proportion of flow1
Tributary
Mouth
Clear water areas that exist where tributaries flow into Susitna River main channel or side channel habitats (upstream
Tributary habitat will be mapped as a separate effort).
Off-Channel
Habitat2
Side Slough Overflow channel contained in the floodplain, but disconnected from the main channel.
Upland
Slough
Similar to a side slough, but contains a vegetated bar at the head that is rarely overtopped by mainstem flow. Has clear
water.1.
Tributary
Habitat
Single
Channel Single dominant channel
Split Channel Two dominant channels
Channel
complex Three or more distributed dominant channels
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Table 1.1-1. (continued)
Level Unit Grouping Category Definitions
4 Mesohabitat
Fast
water
Rapid
Swift, turbulent flow including small chutes and some hydraulic jumps swirling around boulders. Exposed substrate
composed of individual boulders, boulder clusters, and partial bars. Lower gradient and less dense concentration of
boulders and white water than Cascade. Moderate gradient; usually 2.0-4.0 percent slope.2
Riffle A fast water habitat with turbulent, shallow flow over submerged or partially submerged gravel and cobble substrates.
Generally broad, uniform cross-section. Low gradient; usually 0.5-2.0 percent slope.2
Run
A habitat area with minimal surface turbulence over or around protruding boulders with generally uniform depth that is
generally greater than the maximum substrate size. 2 Velocities are on border of fast and slow water. Gradients are
approximately 0.5 percent to less than 2 percent. Generally deeper than riffles with few major flow obstructions and
low habitat complexity.2
Glide
An area with generally uniform depth and flow with no surface turbulence. Low gradient; 0-1 percent slope. Glides
may have some small scour areas but are distinguished from pools by their overall homogeneity and lack of structure.
Generally deeper than riffles with few major flow obstructions and low habitat complexity.2
Slow
Water Pool Slow water habitat with minimal turbulence and deeper due to a strong hydraulic control.
Special
Habitat
Feature
Clearwater
Plume
Discharge from a tributary that forms a pronounced area of clearwater, in contrast to the turbid water of the main
channel, along the main channel shoreline. The length, breadth, and depth of the clearwater plume depend on the
relative discharge between the tributary and the main channel, relative turbidity, and on mixing conditions along the
shoreline. A clear water plume will be mapped as if it were a separate mesohabitat type.
Backwater Found along channel margins and generally within the influence of the active main channel with no independent
source of inflow. Water is not clear. A backwater will be mapped as if it were a separate mesohabitat type.
Beaver
Complex
Complex ponded water body created by beaver dams. A beaver dam will be mapped as if it were a separate
mesohabitat type.
Tributary
Mesohabitat Tributary mesohabitats were typed using the classification system described in Table 1.1-2
Notes:
1 For the purposes of this ISR, classification of the Lower River segment stopped at Level 2. A classification system for the Lower River segment is still in
development pending determination of Project effects in the Lower River.
2 All habitat within this designation received an additional designation of whether water was clear or turbid within the database.
3 The terms Side Channel, Slough, and Upland Slough are similar but not necessarily synonymous with the terms for macrohabitat type as applied by Trihey
(1982) and ADF&G (1983).
4 All slough habitat will have an associated area created during the mapping process to better classify size.
5 Adapted from Moore et al. 2006.
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Table 1.1-2. Nested and Tiered Habitat Mapping Units and Hydraulic Categories Used for Mesohabitats in Tributary Surveys.
Macrohabitat (# of channels) Hydraulic Type Mesohabitat Type Definition
Main channel
(1 channel)
Split main
channel
(2 channels)
Multiple split
main channel
(3 or >
channels)
Fast Water
Falls Steep near vertical drop in water surface elevation greater than approximately 5 feet over a permanent feature, generally
bedrock.
Cascade
A fast water habitat with turbulent flow; many hydraulic jumps, strong chutes, and eddies and between 30-80 percent white
water. High gradient; usually greater than 4 percent slope. Much of the exposed substrate composed of boulders organized
into clusters, partial bars, or step-pool sequences. 1
Chute
An area where most of the flow is constricted to a channel much narrower than the average channel width. Laterally
concentrated flow is generally created by a channel impingement or a laterally asymmetric bathymetric profile. Flow is fast
and turbulent.
Rapid
Swift, turbulent flow including small chutes and some hydraulic jumps swirling around boulders. Exposed substrate
composed of individual boulders, boulder clusters, and partial bars. Lower gradient and less dense concentration of
boulders and white water than Cascade. Moderate gradient; usually 2.0-4.0 percent slope, occasionally 7.0-8.0 percent. 1
Boulder Riffle Same flow and gradient as Riffle but with numerous boulders that can create sub-unit sized pools or pocket water created by
scour.
Riffle A fast water habitat with turbulent, shallow flow over submerged or partially submerged gravel and cobble substrates.
Generally broad, uniform cross-section.1 Low gradient; usually 0.5-2.0 percent slope, rarely up to 6 percent.
Run/Glide
A habitat area with minimal surface turbulence with generally uniform depth that is greater than the maximum substrate
size.1 Velocities are on border of fast and slow water. Gradients are approximately 0 to less than 2 percent. Generally
deeper than riffles with few major flow obstructions and low habitat complexity.1
Slow Water
Pool A slow water habitat with a flat surface slope and low water velocity that is deeper than the average channel depth.
Substrate is highly variable. 1
Pool subtypes
Straight Scour Pool: Formed by mid-channel scour. Generally with a broad scour hole and symmetrical cross-section.1
Plunge Pool: Formed by scour below a complete or nearly complete channel obstruction (logs, boulders, or bedrock). Pool
must be Substrate is highly variable. Frequently, but not always, shorter than the active channel width.1
Lateral Scour Pool: Formed by flow impinging against one stream bank or partial obstruction (logs, root wad, or bedrock).
Asymmetrical cross-section. Includes corner pools in meandering lowland or valley bottom streams.1
Backwater Pool: Found along channel margins; created by eddies around obstructions such as boulders, root wads, or
woody debris. Part of active channel at most flows; scoured at high flow. Substrate typically sand, gravel, and cobble.
Generally not as long as the full channel width. 1
Beaver Pond Water impounded by the creation of a beaver dam. Maybe within main, side, or off-channel habitats. 1
Alcove An off-channel habitat that is laterally displaced from the general bounds of the active channel and formed during extreme
flow events or by beaver activity; not scoured during typical high flows. Substrate is typically sand and organic matter.
Generally not as long as the full channel width. An alcove is differentiated from a backwater being more protected and not
scoured at high flows whereas a backwater is part of the active channel and is scoured at high flows 1
Off-channel Percolation
channel
A slough characterized by groundwater percolation through the floodplain that comes from main stream channel. Upstream
surface connection to active channel cut off due to accumulation of sediment/debris at the upstream end. Upstream surface
water connection to the active channel present only during high flows.
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Table 4.1-1. Upper River Tributary Table Showing all Tributary Geomorphic Reaches, Gradient, Basin Area, Private Land Ownership, and 2013 Survey Status.
Mainstem Geomorphic
Reach
Tributary Name (ID) Tributary
Category2
Tributary Geomorphic
Reach
Project
River
Mile
End of
Survey
Elev. (ft)
Approx. Drainage Area (km2)
Approx. Length
(km)
Total
Grad. (%)
Ground
survey
UR-3 Oshetna River – LB1 1
Oshetna-1
235.1 3,000 885.1 89.48
y
Oshetna-2 y
Oshetna-33 y
UR-3 Black River - LB1 2
Black-1
12.7 (LB) 3,000 NI NI
y
Black-2 y
Black-3 y
UR-3 Goose Creek – LB1 1
Goose-1
232.8 3,000 167.2 40.56
y
Goose-2 y
Goose-33 y
Proposed reservoir full pool
UR-3 230.7 1 230.8 1 2.19 11 UR-3 230.2 1 230.2 0.4 0.72 19 UR-3 230.1 1 230.1 4.3 5.39 7 UR-3 228.5 1 228.5 75.1 25.39 5 UR-3 226.2 1 226.2 5.9 4.50 10 UR-3 219.6 1 219.6 8.4 7.28 8 UR-3 214.4 1 214.4 1.7 2.44 23
UR-4 Jay Creek - RB1 1
Jay-1
211.0 3,000 99.5 31.54
y4
Jay-2 y4
Jay-3 y
Jay-4 y
UR-4 Kosina Creek - LB1 1
Kosina-1
209.1 3,000 644.1 63.57
y4
Kosina-2 y4
Kosina-3 y4
UR-4 Tsisi Creek - LB1 2 Tsisi-13 7.4 (LB) 3,000 NI NI
y
Tsisi-23 y
UR-4 208.6 1 208.6 5.0 7.52 8 UR5 207.4 - RB 1 207.4 1.1 2.50 14 UR-5 207.4 RB-1 207.4 2,200 NI
UR-5 206.3 - LB 1
206.3-1
206.3 3,000 49.9 11.96
y
206.3-2 y
206.3-3 y
UR-5 204.3-LB 1 204.3-1 204.3 3,000 49.9 9.98
*
204.3-2 UR-6 198.9 1 198.9 1.2 3.36 13 UR-6 198.4 LB -1 2 198.4 2,200 NI
UR-6 197.7 1
197.7-1
197.7 3,000 49.9 8.69
*
197.7-2 *
197.7-3 *
UR-6 197.7 RB-1 2 197.7 2,200 NI
UR-6 Watana Creek1 1
Watana-1
196.9 3,000 281.3 43.29
y4*
Watana-2 y4
Watana-33 y4
UR-6 RB 1 2 196.9 1,850 NI *
UR-6 LB 1.1.1 4 196.9 2,000 NI *
UR-6 Watana Tributary - RB1 2 Watana Trib-13 8.7 (RB) 3,000 NI NI
y
Watana Trib-23 y
UR-6 194.8 - RB 1
194.8-1
194.8 3,000 199.6 11.43
*
194.8-2 y
194.8-3 y
194.8-4 y
UR-6 Deadman Creek - RB1 1
Deadman-1
189.4 3,000 281.8 67.43
*
Deadman-2 *
Deadman-3 y
Deadman-4 y
Deadman-5 y
Deadman-6 y
Notes:
1 Tributary mapped using aerial videography.
2 Tributary Category indicates ranked distance from the mainstem Susitna River (i.e., 1 = primary tributary to the Susitna River, 2 = tributary to a number 1
tributary)
3 Tributary Geomorphic Reach only partially video-mapped or not video mapped. See Table 4.1-3 for spatial range of videography survey.
4 All or part of tributary geomorphic reach survey conducted during 2012
NI No information available at this time.
* Private land CIRWG
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Table 4.1-2. . Middle River Tributary Geomorphic Reaches Selected for Field-Survey, Gradient, Basin Area, Private Land Ownership, and 2013 Survey Completion
Status.
Mainstem Geomorphic Reach Tributary Name (ID) Tributary
Category2
Tributary Geomorphic Reach
Project River Mile
End of Survey Elev. (ft)
Approx. Drainage Area (km2)
Approx. Length (km) Focus Area Ground survey 2013
MR-2 Tsusena Creek - RB1 1 Tsusena-1 184.6 barrier 145.3 49.41 NA *
Tsusena-2 NA
MR-2 184.0 - RB1 1 184.0-1 184.0 barrier <31 16.74 NA *
184.0-2 NA *
MR-2 Unnamed - LB NI NA 174.3 upper extent
of ZHI NI NI
FA-173
(Stephan Lake
Complex)
*
MR-2 173.8 - RB NI NA 173.8 upper extent
of ZHI NI NI
FA-173
(Stephan Lake
Complex)
y*
MR-2 Fog Creek - LB1 1
Fog-1
179.3 3,000 147.2 44.74
NA *
Fog-2 NA *
Fog-3 NA *
Fog-43 NA y
Devils Canyon upper extent
MR-4 Devil Creek - RB1 1 Devil-1 164.8 barrier 74.8 25.43 NA *
MR-4 Chinook Creek - LB1 1 Chinook-1 160.5 3,000 24.7 17.06 NA y*
Chinook-23 NA y
MR-4 Cheechako Creek - LB1 1 Cheechako-1 155.9 barrier 36.4 17.22 NA *
Devils Canyon lower extent
MR-5 Portage Creek NA 152.3 upper extent
of ZHI 178.6 0.31 FA-151
(Portage Cr) *
MR-6 Jack Long Creek NA 148.3 upper extent
of ZHI NI 0.05 NA *
MR-6 Unnamed NA 144.6 upper extent
of ZHI NI 0.02 FA-144
(Slough 21)
MR-6 Indian River NA 142.1 upper extent
of ZHI 86.2 0.23 FA-141
(Indian River) y
MR-6 Gold Creek NA 140.1 upper extent
of ZHI 23.7 0.24 NA y
MR-6 Fourth of July Creek NA 134.3 upper extent
of ZHI NI 0.19 NA
MR-6 Sherman Creek NA 134.1 upper extent
of ZHI NI 0.03 NA **
MR-6 Skull Creek NA 128.1 upper extent
of ZHI NI 0.06 FA-128
(Slough 8A) **
MR-6 Fifth of July Creek NA 127.3 upper extent
of ZHI NI 0.02 NA
MR-6 Deadhorse Creek NA 124.4 upper extent
of ZHI 6.5 0.29 NA **
MR-7 Little Portage Creek NA 121.4 upper extent
of ZHI 2.4 0.19 NA **
MR-7 McKenzie Creek NA 120.2 upper extent
of ZHI 2.3 0.03 NA **
MR-7 Lower McKenzie Creek NA 119.7 upper extent
of ZHI NI 0.26 NA **
MR-7 Lane Creek NA 117.2 upper extent
of ZHI 10.4 0.18 NA **
MR-7 Unnamed NA 115.4 upper extent
of ZHI NI 0.19 FA-115
(Slough 6A) y**
MR-7 Gash Creek NA 115.0 upper extent
of ZHI NI 0.02 FA-113
(Oxbow 1) **
MR-7 Slash Creek NA 114.9 upper extent
of ZHI NI 0.03 FA-113
(Oxbow 1) **
MR-7 Unnamed NA 113.7 upper extent
of ZHI NI NI FA-113
(Oxbow 1) y**
MR-7 Chase Creek NA 110.5 upper extent
of ZHI NI 0.27 NA y
MR-8 Whiskers Creek NA 105.1 upper extent
of ZHI 17.2 0.53
FA-104
(Whiskers
Slough)
y
Notes:
1 Tributary mapped using aerial videography
2 Tributary category indicates ranked distance from the mainstem Susitna River (i.e. 1 = primary tributary to the Susitna River, 2 = tributary to a number 1
tributary)
3 Tributary geomorphic reach only partially video-mapped or not video-mapped. See Table 4.1-3 for spatial range of videography survey
NI No information available at this time
* private land: CIRWG
** private land: ARRC
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Table 4.1-3. Tributary geomorphic reach mesohabitat frequency and composition derived from videography 2012.
Tributary Geomorphic Reach Alcove Beaver Pond Boulder Riffle Cascade Chute Falls Percolation Pool Rapid Riffle Run/Glide Split Out-of-view All Units
n Percent n Percent n Percent n Percent n Percent n Percent n Percent n Percent n Percent n Percent n Percent n Percent n Percent n
Upper River
Oshetna River Oshetna-1 0 0 0 0 86 42 0 0 1 0 0 0 0 0 4 2 15 7 50 25 46 23 2 1 4 NA 208
Oshetna-2 0 0 16 25 21 33 0 0 0 0 0 0 0 0 0 0 1 2 9 14 1 2 15 24 9 NA 72
Oshetna-31 0 0 0 0 36 18 0 0 0 0 0 0 0 0 7 4 3 2 38 19 67 34 44 23 25 NA 220
Black River Black-1 0 0 0 0 7 12 0 0 0 0 0 0 0 0 1 2 0 0 1 2 20 34 29 50 0 NA 58
Black-2 0 0 0 0 15 42 0 0 0 0 0 0 0 0 3 8 1 3 3 8 8 22 6 17 0 NA 36
Black-3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 NA 0
Goose Creek Goose-1 0 0 0 0 43 28 1 1 0 0 0 0 0 0 3 2 37 24 1 1 39 25 32 21 2 NA 158
Goose-2 0 0 0 0 31 34 0 0 0 0 0 0 0 0 2 2 9 10 1 1 33 36 16 17 0 NA 92
Goose-3 No Data
Proposed reservoir full pool Jay Creek Jay-1 0 0 0 0 11 21 0 0 0 0 0 0 0 0 2 4 5 9 8 15 13 25 14 26 0 NA 53
Jay-2 0 0 0 0 52 34 3 2 4 3 0 0 0 0 6 4 26 17 16 11 32 21 13 9 4 NA 156
Jay-3 0 0 0 0 20 12 0 0 0 0 0 0 0 0 16 9 9 5 13 8 84 49 28 16 5 NA 175
Jay-4 0 0 0 0 4 5 0 0 0 0 0 0 0 0 11 13 2 2 13 16 44 53 9 11 1 NA 84
Kosina Creek Kosina-1 0 0 0 0 18 8 0 0 0 0 0 0 0 0 4 2 104 49 0 0 27 13 59 28 21 NA 233
Kosina-2 0 0 0 0 18 8 0 0 0 0 0 0 0 0 4 2 104 49 0 0 27 13 59 28 21 NA 233
Kosina-3 0 0 0 0 60 28 0 0 0 0 0 0 0 0 3 1 3 1 16 7 61 28 75 34 0 NA 218
Tsisi Creek Tsisi-12 0 0 0 0 50 38 4 3 0 0 0 0 0 0 0 0 56 43 0 0 2 2 18 14 0 NA 130
Tsisi-23 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 NA 0
Unnamed 206.3 206.3-1 No Data
206.3-2 No Data
206.3-3 No Data
Unnamed 204.3 204.3-1 No Data
204.3-2 No Data
Unnamed 197.7 197.7-1 No Data
197.7-2 No Data
197.7-3 No Data
Watana Creek Watana-1 0 0 0 0 20 5 0 0 0 0 0 0 0 0 14 4 30 8 30 8 208 55 75 20 7 NA 384
Watana-2 0 0 0 0 11 6 1 1 2 1 0 0 0 0 7 4 66 35 6 3 57 30 37 20 3 NA 190
Watana-34 0 0 0 0 9 13 0 0 0 0 0 0 0 0 0 0 3 4 5 7 10 14 43 61 2 NA 72
Watana Trib Watana Trib-15 0 0 0 0 10 10 0 0 0 0 0 0 0 0 1 1 3 3 1 1 78 74 12 11 0 NA 105
Unnamed 194.8 194.8-1 No Data
194.8-2 No Data
194.8-3 No Data
194.8-4 No Data
Deadman Creek Deadman-1 0 0 0 0 1 13 0 0 0 0 0 0 0 0 1 13 6 75 0 0 0 0 0 0 0 NA 8
Deadman-2 0 0 0 0 0 0 14 50 6 21 2 7 0 0 3 11 3 11 0 0 0 0 0 0 1 NA 29
Deadman-3 0 0 0 0 21 30 2 3 0 0 0 0 0 0 5 7 32 46 0 0 0 0 10 14 0 NA 70
Deadman-4 0 0 0 0 28 22 0 0 0 0 0 0 0 0 6 5 21 16 12 9 34 26 29 22 1 NA 131
Deadman-5 0 0 0 0 19 31 0 0 0 0 0 0 0 0 2 3 25 40 0 0 13 21 3 5 1 NA 63
Upper River Total 0 0 16 0 591 19 25 2 13 1 2 0 0 0 105 4 564 18 223 6 904 23 628 18 107 NA 3,178
Middle River
Tsusena Creek Tsusena-1 0 0 0 0 2 3 1 1 0 0 0 0 0 0 1 1 37 50 0 0 18 24 15 20 0 NA 74
Tsusena-2 0 0 0 0 0 0 8 16 4 8 0 0 0 0 6 12 18 35 0 0 12 24 3 6 1 NA 52
Unnamed 184.0 184.0-1 0 0 0 0 2 6 5 14 0 0 0 0 0 0 1 3 21 60 0 0 5 14 1 3 0 NA 35
184.0-2 0 0 0 0 0 0 12 26 2 4 1 2 0 0 0 0 24 52 0 0 7 15 0 0 3 NA 49
Fog Creek Fog-1 0 0 0 0 3 8 0 0 0 0 0 0 0 0 2 5 3 8 2 5 2 5 27 69 0 NA 39
Fog-2 0 0 0 0 25 21 11 9 5 4 0 0 0 0 15 13 51 43 7 6 1 1 5 4 1 NA 121
Fog-3 0 0 0 0 83 15 0 0 0 0 0 0 0 0 53 10 18 3 164 30 125 23 106 19 34 NA 583
Fog-46 0 0 0 0 5 26 0 0 0 0 0 0 0 0 1 5 7 37 2 11 0 0 4 21 2 NA 21
Fog Trib Fog Trib-17 0 0 0 0 2 1 46 18 6 2 0 0 0 0 5 2 105 41 1 0 41 16 51 20 5 NA 262
Upper extent of Devils Canyon
Chinook Creek Chinook-1 0 0 0 0 2 2 20 17 14 12 0 0 0 0 5 4 63 54 0 0 12 10 0 0 21 NA 137
Chinook-28 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 22 42 2 4 11 21 16 31 7 NA 59
Cheechako Creek Cheechako-1 0 0 0 0 4 5 19 26 9 12 3 4 0 0 11 15 21 28 0 0 7 9 0 0 8 NA 82
Lower extent of Devils Canyon
Middle River Total 0 0 0 0 134 7 136 11 50 4 4 0 0 0 100 5 431 39 178 4 247 13 233 15 82 NA 1,595
1Video went to TRM 15.6 but reach extends to TRM 25.6
2Video stops at RM 2.7 so habitat frequencies in table above only go from RM 0.1 to RM 2.7 (not full reach length of 3.5). 3No video, channel form is assumed based on topography and location within the watershed. 4Video stops at RM 17.25, habitat frequencies in table above only go from RM 14.41 to RM 17.25 (not full reach length of 21.5). The helicopter video only extends to RM 17.25 but it is assumed the rest of the reach continues in the same character. 5Video stops at RM 2.95, habitat frequencies in table above only go from RM 0.1 to RM 2.95 (not full reach length of 10.7). After the helicopter video ends, it is assumed the channel continues in the same character to RM 4.6, where it splits. The main channel is assumed to go to the right through the broad valley up to the
drainage break into Butte Creek.
6Helicopter did not extend to 3,000 ft elevation but same character is inferred and stream just gets smaller. This reach was only mapped to RM 17.975 so habitat above this point is not included. 7Video mapping only goes to RM 7.38, habitat units after RM 7.38 not included. 8Video mapping only goes to RM 7.1 habitat units above RM 7.1 are not included.
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Table 4.2-1. Randomly selected Upper and Middle River mainstem habitats versus those surveyed during 2013.
Remote Habitat Type Mesohabitat Replicate
Geomorphic Reach Total Selected
20131
Total Surveyed
2013 2 3 4* 5 6 7 8
Surv. Not Surv. Surv. Not Surv. Surv. Not Surv. Surv. Not Surv. Surv. Not Surv. Surv. Not Surv. Surv. Not Surv.
Upper River
Main Channel UR Rapid2 0 3 0 1 0 3 7 0
UR Riffle 5 0 2 0 7 7
UR Glide or Run 4 0 2 0 1 0 7 7
Split Main Channel - 4 0 1 0 1 1 7 6
Side Channel - 3 0 3 1 7 6
Side Slough - 1 0 2 2 0 2 7 3
Upland Slough - 3 2 0 1 6 3
Upper River Total 10 3 16 4 1 1 5 8 48 32
Middle River
Main Channel MR Rapid2 0 7 7 0
MR Pool2 0 2 2 0
MR Riffle 1 0 1 0 0 3 1 0 1 0 7 4
MR Glide or Run 1 0 0 1 2 0 2 0 1 0 7 6
Split Main Channel - 1 0 1 0 2 1 1 0 1 0 7 6
Multi Split Main Channel - 3 0 4 0 7 7
Side Channel - 1 0 2 1 1 0 2 0 7 6
Side Slough - 4 1 1 0 6 5
Beaver Complex 1 0 1 1
Upland Slough - 2 0 2 1 5 4
Beaver Complex 1 1 2 1
Middle River Total 1 0 4 0 0 13 1 0 17 4 9 1 8 0 56 39
Notes:
1 Total number of habitat units selected and existing by river segment
2 All mainstem Susitna River rapids and pools were deemed unsafe to access and were not surveyed
* All habitat units in Middle River geomorphic reach 4 are within or near Devils Canyon, were deemed unsafe and will not be ground surveyed
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Table 4.2-2. Lakes in the Upper River located within the inundation zone, and habitat metrics obtained from the Project
GIS database.
Lake ID1 Perimeter (m) Elevation (ft) Area (ha) Surface water connection
Lake 1 260 1,752 0.23 Yes
Lake 2 543 1,750 0.68 Yes
Lake 3 1001 1,796 3.37 Yes
Lake 4 441 2,042 1.15 No
Lake 5/Sally Lake 3009 2,034 22.99 Yes
Lake 6 399 2,008 0.89 No
Lake 7 467 1,598 1.48 Indeterminate
Lake 8 211 2,030 0.30 No
Lake 9 419 1,782 1.15 Yes
Lake 10 144 1,958 0.16 No
Lake 11 198 2,038 0.20 No
Lake 12 391 2,008 0.72 No
Note:
1 Lakes are ordered from most upstream to most downstream.
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Table 4.2-3 Project River Mile ranges for areas not surveyed due to access restrictions due to private land and safety
considerations.
PRM Start PRM End Access Limitation Focus Area
Upper River
Proposed reservoir full pool
225.2 226.6 Safety/confined channel
196.6 196.8 Private CIRWG land
194.5 194.7 Private CIRWG land
193.4 193.7 Private CIRWG land
187.6 189.3 Safety/confined channel
Middle River
178.3 178.5 Private CIRWG land
176.2 176.8 Private CIRWG land
173.6 175.4 Private CIRWG land FA-173 (Stephan Lake Complex)
Devils Canyon Upper Extent
153.9 166.1 Devils Canyon
Devils Canyon Lower Extent
151.8 152.7 Private CIRWG land Includes FA-151 (Portage Creek)
147.6 148.1 Private CIRWG land
128.1 128.6 Private ARRC land FA-128 (Slough 8A)
126.8 123.4 Private ARRC land
108.6 109.0 Private ARRC land
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Table 4.2-4. Range of mean daily flows at the USGS 15292000 Susitna River at Gold Creek real time streamflow gage during 2013 ground surveys.
Geo.
Reach Focus Area Ground Macrohabitat Count <18,000 cfs 18,000-25,000 cfs 25,000-30,000 cfs >30,000 cfs No Information
Upper River
UR-3 NA Main Channel 9 Side Slough6 1 UR-4 NA Main Channel 3 3 Split Main Channel 2 1 Side Channel 1 1 Side Slough6 2 1 Upland Slough 2 1 UR-5 NA Split Main Channel 1 UR-6 NA Main Channel 1 Split Main Channel 1 Multi Split Main Channel 1 Side Channel 1 1 Upper River Total 5 9 19 Middle River
MR-1 FA-184 (Watana Dam) Main Channel 1 Side Channel 2 MR-2 FA-173 (Stephan Lake Complex) Main Channel 1 Side Channel 3 4 Tributary Mouth 1 Side Slough 1 1 3 NA Main Channel 1 MR-3 NA Main Channel 2 Split Main Channel 2 Devils Canyon
MR-5 NA Split Main Channel 1 MR-6 FA-144 (Slough 21) Main Channel 2 Multi Split Main Channel 2 Side Channel 1 Side Slough 2 1
Upland Slough 1 Not Recorded 1 FA-141 (Indian River) Main Channel 3 Multi Split Main Channel 6 Side Channel 3 Tributary Mouth 1 Upland Slough 4 2 Not Recorded 1
FA-138 (Gold Creek) Main Channel 1 Split Main Channel 1 Multi Split Main Channel 2 Side Channel 2 Side Slough 1 Upland Slough 2 Not Recorded 6 1
FA-128 (Slough 8A) Main Channel 1 Side Channel 3 6 2
Tributary Mouth 1 Side Slough 1 Upland Slough 3 Not Recorded 1
NA Main Channel 2 1 Multi Split Main Channel 2 2 Side Channel 2 Side Slough 1 4 Upland Slough 3 Not Recorded 1
MR-7 FA-115 (Slough 6A) Split Main Channel 2 3
Side Slough 1 Upland Slough 3 1
Not Recorded 2
FA-113 (Oxbow 1) Main Channel 1 Split Main Channel 11 Side Channel 1 Side Slough 4 Upland Slough 3 Not Recorded 1 NA Main Channel 3 Split Main Channel 1 Side Channel 1 Side Slough 3 Upland Slough 2 MR-8 FA-104 (Whiskers Slough) Main Channel 1 Split Main Channel 1 Side Channel 9 1 Side Slough 5 5 Upland Slough 2 NA Main Channel 1 Split Main Channel 1 Multi Split Main Channel 5 Side Channel 2 Middle River Total 72 83 6 7 13
Notes:
1 Range: 15,400-17,700 cfs, 2Range: 18,300-21,700 cfs, 3Range: 25,900-29,500 cfs, 4Range: 30,700-31,400 cfs
5 No date or flow information available from field data.
6 Side Sloughs in the Upper River were evaluated prior to surveys to ensure that the head of the unit was not breached during flows > 18,000 cfs at the Susitna River at Gold Creek gage.
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Table 4.3-1. Focus Area habitats surveyed during 2013, and those required for survey in the next year of study to complete 100 percent sampling.
Geomorphic Reach Focus Area
Main Channel Split Main Channel Multi Split Main Channel Side Channel Tributary Mouth Side Slough Upland Slough Backwater Clearwater Plume No Remote Mapping1 TOTAL
2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed 2013 To be
surveyed
MR-1 FA-184
(Watana Dam) 1 0 2 0 3 0
MR-2 FA-173
(Stephan Lake Complex) 1 0 5 0 1 0 3 1 0 2 4 0 14 3
MR-5 FA-151
(Portage Cr) 0 1 0 1 0 1 0 3
MR-6 FA-144
(Slough 21) 4 0 1 7 1 0 3 0 9 7
FA-141
(Indian River) 2 1 6 0 0 2 1 0 4 0 1 0 1 0 1 0 16 3
FA-138
(Gold Creek) 1 0 2 1 3 0 1 0 2 2 1 1 10 4
FA-128
(Slough 8A) 1 0 8 2 1 0 1 1 3 0 1 0 15 3
MR-7 FA-115
(Slough 6A) 1 1 4 1 1 0 3 0 1 0 10 2
FA-113
(Oxbow 1) 1 0 12 0 3 0 2 0 18 0
MR-8 FA-104
(Whiskers Slough) 1 0 10 1 5 0 3 0 19 1
Total 13 3 16 1 8 1 33 12 3 1 11 2 20 4 2 0 1 1 7 1 114 26
Note:
1 Macrohabitat unit was not identified during the remote mapping process.
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Table 5.1-1. Sum of length (m) surveyed, and composition by length of mesohabitats in Upper River and Middle River tributaries surveyed betw een August 3 and September 22, 2013.
Tributary Name Geomorphic Reach Focus Area
Alcove Beaver Pond Boulder Riffle Cascade Glide Percolation Channel Pool Rapid Riffle Run All Units2
n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Total Length Surveyed (m)
Upper River
Oshetna River Oshetna-1 - 5 483 12 2 186 5 2 228 6 6 1,848 47 5 1,227 31 20 3,972
Oshetna-2 - 3 792 81 1 67 7 1 115 12 5 974
Oshetna-3 - 5 616 16 2 196 5 2 590 15 8 921 23 13 1,614 41 30 3,936
Black River Black-1 - 4 494 24 2 281 13 1 34 2 6 1,090 52 4 190 9 17 2,089
Black-2 - 7 593 54 1 60 5 3 187 17 6 263 24 17 1,103
Black-3 - 5 207 15 2 69 5 5 586 43 5 506 37 17 1,368
Goose Creek Goose-1 - 7 1,056 75 1 58 4 5 164 12 5 129 9 18 1,407
Goose-2 - 5 675 58 3 317 27 5 167 14 13 1,158
Goose-3 - 5 247 41 1 118 19 6 243 40 12 609
Proposed reservoir full pool
Jay Creek Jay-1 - 4 435 89 1 37 7 1 20 4 6 492
Jay-2 - 5 256 24 6 640 60 2 128 12 2 38 4 15 1,062
Jay-3 - 4 236 75 2 78 25 6 314
Jay-4 - 1 7 1 5 187 37 5 102 20 5 187 37 1 21 4 17 503
Kosina Creek Kosina-2 - 5 428 100 5 428
Tsisi Creek Tsisi-1 - 8 469 46 1 140 14 6 407 40 15 1,016
Tsisi-2 - 5 381 62 5 236 38 10 617
Unnamed Trib
206.3
UnnamedTrib206.3-
1 - 5 75 30 6 119 47 1 40 16 1 18 7 13 253
UnnamedTrib206.3-
3 - 1 3 16 2 10 50 1 7 34 4 20
Watana Creek Watana-1 - 1 98 15 2 113 17 4 357 53 2 100 15 9 668
Watana-2 - 2 81 28 1 22 8 2 35 12 2 59 20 3 95 33 10 291
Watana-3 - 2 29 3 13 470 50 3 59 6 3 122 13 7 269 28 28 948
Unnamed Watana Trib 1 Watana Trib-1 - 3 26 4 1 21 3 1 18 3 1 22 3 4 109 16 2 151 22 12 345 50 24 691
Unnamed Trib
194.8
UnnamedTrib194.8-
3 - 1 37 6 2 20 3 2 22 3 10 366 55 3 39 6 1 5 1 6 178 27 25 667
UnnamedTrib194.8-
4 - 6 71 44 4 89 56 10 159
Deadman Creek Deadman-3 - 5 428 22 2 164 9 2 635 33 5 651 34 1 29 1 15 1,906
Deadman-4 - 5 1,282 44 2 501 17 1 140 5 5 469 16 3 498 17 16 2,890
Deadman-5 5 623 52 5 567 48 10 1,190
Deadman-6 - 5 1,155 57 6 868 43 11 2,022
Total1 3 36 0 1 37 0 105 8,869 27 15 683 2 20 2,666 8 1 18 0 29 1,504 5 60 5,343 16 63 7,124 22 101 6473 20 398 32,753
Middle River
Fog Creek Fog-4 - 5 716 65 5 163 15 5 188 17 1 40 4 16 1,107
Unnamed Tributary
173.8 NA FA-173 (Stephan Lake
Complex) 3 867 80 4 21 2 4 191 18 11 1,079
Devils Canyon upper extent
Chinook Creek Chinook-1 - 5 185 33 5 341 60 2 39 7 12 564
Chinook-2 - 1 5 1 1 45 9 1 6 1 1 36 7 5 352 71 5 50 10 14 494
Devils Canyon lower extent
Indian River NA FA-141 (Indian River) 1 8 1 7 264 22 6 122 10 9 402 33 3 422 35 26 1,218
Gold Creek NA - 1 30 6 2 35 8 5 339 73 3 59 13 11 463
Unnamed Tributary
115.4 NA FA-115 (Slough 6A) 5 411 97 2 7 2 1 4 1 8 421
Chase Creek NA - 1 234 85 1 28 10 1 12 4 3 274
Whiskers Creek NA FA-104 (Whiskers
Slough) 1 2 0 14 478 26 17 761 41 14 398 21 7 230 12 53 1,868
Total1 3 15 0 0 0 0 9 1,629 22 5 185 2 24 1,012 14 1 36 0 33 1,342 18 17 891 12 40 1,537 21 22 842 11 154 7,488
1Total number of measurements (n) and group mean (SD) for each mesohabitat type per River Segment.
2Total number of measurements (n) and group mean (SD) for each geomorphic reach.
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Table 5.1-2. Mean (±SD) percent gradient of mesohabitats in Upper River and Middle River tributaries surveyed between August 3 and September 22, 2013.
Tributary Name Geomorphic Reach Focus Area Alcove Beaver Pond Boulder Riffle Cascade Glide Percolation Channel Pool Rapid Riffle Run All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
Oshetna River Oshetna-1 - 5 1.0 0.0 2 0.2 0.0 2 2.5 0.7 6 1.2 0.7 5 1.0 0.6 20 1.1 0.7
Oshetna-2 - 3 1.5 0.5 1 1.0 NA 1 1.0 NA 5 1.3 0.4
Oshetna-3 - 5 0.4 0.1 2 0.3 0.4 1 2.0 NA 8 0.6 0.6 13 0.6 0.5 29 0.6 0.5
Black River Black-1 - 4 2.5 1.2 2 0.5 0.0 1 0.0 NA 6 1.1 0.5 4 0.8 0.3 17 1.2 1.0
Black-2 - 7 2.5 0.6 1 3.0 3 1.2 0.8 6 0.4 0.3 17 1.6 1.1
Black-3 - 5 1.8 0.8 2 2.3 0.4 5 1.1 0.4 5 0.6 0.4 17 1.3 0.8
Goose Creek Goose-1 - 7 2.9 1.2 1 4.0 NA 5 4.0 1.7 5 1.0 1.1 18 2.7 1.7
Goose-2 - 5 1.8 0.6 3 12.0 15.6 5 0.4 0.4 13 3.6 8.0
Goose-3 - 5 0.9 0.2 1 1.0 NA 6 0.4 0.2 12 0.6 0.3
Proposed reservoir full pool
Jay Creek Jay-1 - 4 3.3 0.6 1 5.0 NA 1 3.0 NA 6 3.5 0.9
Jay-2 - 5 1.6 0.4 6 3.3 1.4 2 1.8 0.4 2 1.3 0.4 15 2.3 1.3
Jay-3 - 4 2.3 0.6 2 0.8 0.4 6 1.8 0.9
Jay-4 - 1 0.0 NA 5 0.7 0.3 5 0.5 0.0 5 1.5 0.5 1 1.0 NA 17 0.9 0.6
Kosina Creek Kosina-2 - 5 3.3 1.0 5 3.3 1.0
Tsisi Creek Tsisi-1 - 8 2.0 0.5 1 0.5 NA 6 2.3 0.9 15 2.0 0.8
Tsisi-2 - 5 1.0 0.6 5 0.4 0.2 10 0.7 0.5
Unnamed Trib 206.3 UnnamedTrib206.3-1 - 5 10.5 3.5 6 11.2 1.8 1 6.0 NA 1 8.0 NA 13 10.3 2.8
UnnamedTrib206.3-3 - 1 20.0 NA 2 9.5 4.9 1 15.0 NA 4 13.5 5.8
Watana Creek Watana-1 - 1 1.5 NA 2 0.3 0.4 4 1.5 0.4 2 1.0 0.0 9 1.1 0.6
Watana-2 - 2 2.0 0.0 1 0.0 NA 2 3.5 2.1 2 1.5 0.0 3 0.8 0.3 10 1.7 1.4
Watana-3 - 2 0.0 0.0 13 1.9 0.3 3 2.8 0.3 3 1.5 0.9 7 1.3 0.7 28 1.7 0.8
Unnamed Watana Trib 1 Watana Trib-1 - 3 2.7 0.3 1 1.0 NA 1 0.0 NA 1 0.0 4 2.6 0.5 2 1.8 0.4 12 1.2 0.6 24 1.5 0.9
Unnamed Trib 194.8 UnnamedTrib194.8-3 - 1 0.0 NA 2 5.0 0.0 2 4.5 0.7 10 0.0 0.0 3 4.7 1.2 1 2.5 NA 6 1.8 0.3 25 1.9 2.0
UnnamedTrib194.8-4 - 6 0.0 0.0 4 2.3 1.0 10 0.9 1.3
Deadman Creek Deadman-3 - 6 1.9 1.0 2 2.0 0.0 2 1.0 0.0 5 2.5 0.5 1 0.5 NA 16 2.0 0.9
Deadman-4 - 5 1.0 0.4 2 0.4 0.2 1 0.2 NA 5 2.0 0.4 3 0.3 0.2 16 1.1 0.8
Deadman-5 5 1.8 0.4 5 1.9 1.0 10 1.9 0.7
Deadman-6 - 4 0.1 0.1 6 0.3 0.2 10 0.2 0.2
Total1 3 0.0 NA 1 0.0 NA 106 2.4 0.6 15 8.9 4.5 19 0.5 0.2 1 0.0 NA 29 0.2 0.1 59 2.9 0.9 63 2.0 0.8 101 1.9 0.4 397 2.4 1.4
Middle River
Fog Creek Fog-4 - 5 3.1 0.9 5 2.8 0.4 5 2.1 0.7 1 1.0 NA 16 2.6 0.9
Unnamed Tributary 173.8 NA FA-173 (Stephan Lake Complex) 3 3.0 1.0 4 0.0 0.0 4 1.4 0.5 11 1.3 1.3
Devils Canyon upper extent
Chinook Creek Chinook-1 - 5 4.4 0.5 5 3.1 1.1 2 1.0 0.0 12 3.3 1.5
Chinook-2 - 1 0.0 NA 1 2.0 NA 1 0.5 NA 1 1.5 NA 5 2.1 0.2 5 1.2 0.6 14 1.5 0.7
Devils Canyon lower extent
Indian River NA FA-141 (Indian River) 7 0.7 0.8 5 0.2 0.4 10 2.0 1.5 3 0.7 0.6 25 1.1 1.3
Gold Creek NA - 1 1.0 NA 2 5.0 2.8 5 4.3 0.9 3 2.5 0.5 11 3.6 1.7
Unnamed Tributary 115.4 NA FA-115 (Slough 6A) 5 0.0 0.0 1 1.0 NA 1 0.0 NA 7 0.1 0.4
Chase Creek NA - 1 0.0 NA 1 0.0 NA 1 4.5 NA 3 1.5 2.6
Whiskers Creek NA FA-104 (Whiskers Slough) 1 0.0 NA 14 0.1 0.1 17 0.0 0.1 13 0.9 0.5 7 0.3 0.2 52 0.3 0.5
Total1 2 0.0 NA 0 NA NA 9 2.7 0.9 5 4.4 0.5 24 0.5 0.4 1 1.5 NA 32 0.0 0.1 17 3.3 1.2 39 2.3 0.8 22 1.0 0.4 151 1.7 1.2
1Total number of measurements (n) and group mean (SD) for each mesohabitat type per River Segment.
2Total number of measurements (n) and group mean (SD) for each geomorphic reach.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 45 February 2014 Draft
Table 5.1-3. Mean (±SD) bankfull width (m) of mesohabitats in Upper River and Middle River tributaries surveyed between August 3 and September 22, 2013.
Tributary Name Geomorphic Reach Focus Area Alcove Beaver Pond Boulder Riffle Cascade Glide Percolation Channel Pool Rapid Riffle Run All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
Oshetna River Oshetna-1 - 15 38 5 6 45 8 6 54 1 18 57 6 15 48 3 60 48 5
Oshetna-2 - 9 51 8 3 72 8 3 57 2 15 57 7
Oshetna-3 - 15 34 5 6 18 3 6 60 6 24 28 3 39 39 3 90 35 3
Black River Black-1 - 10 22 2 5 21 2 2 26 6 13 36 4 8 23 5 38 27 4
Black-2 - 21 22 4 3 23 4 9 15 2 18 19 2 51 20 3
Black-3 - 10 28 1 5 21 2 13 26 3 13 27 3 41 26 3
Goose Creek Goose-1 - 20 18 3 3 19 2 9 14 1 13 15 1 45 16 2
Goose-2 - 15 22 4 9 23 5 15 16 2 39 20 3
Goose-3 - 15 14 2 3 17 3 18 13 3 36 14 2
Proposed reservoir full pool
Jay Creek Jay-1 - 11 10 2 1 9 2 9 0 14 9 2
Jay-2 - 15 16 3 18 12 2 6 13 2 6 10 1 45 13 2
Jay-3 - 10 11 1 4 11 2 14 11 1
Jay-4 - 1 1 10 6 1 10 6 1 10 8 1 2 8 0 33 6 1
Kosina Creek Kosina-2 - 15 35 7 15 35 7
Tsisi Creek Tsisi-1 - 24 15 3 3 5 1 18 15 3 45 14 3
Tsisi-2 - 15 17 2 15 16 2 30 16 2
Unnamed Trib 206.3 UnnamedTrib206.3-1 - 12 5 1 18 4 1 3 4 0 3 5 1 36 5 1
UnnamedTrib206.3-3 - 3 2 0 6 7 2 3 3 1 12 5 1
Watana Creek Watana-1 - 3 19 3 6 35 3 12 36 6 6 24 1 27 31 4
Watana-2 - 6 15 2 3 11 2 6 15 1 6 10 1 9 14 1 30 13 1
Watana-3 - 6 2 0 39 13 1 9 10 1 9 16 2 21 10 2 84 11 1
Unnamed Watana Trib 1 Watana Trib-1 - 4 2 1 2 3 1 3 3 1 3 15 0 9 10 1 6 17 2 29 9 2 56 9 1
Unnamed Trib 194.8 UnnamedTrib194.8-3 - 3 7 2 6 5 1 6 7 1 34 6 1 9 5 1 2 7 1 18 6 1 78 6 1
UnnamedTrib194.8-4 - 18 4 1 12 4 1 30 4 1
Deadman Creek Deadman-3 - 18 30 5 6 23 3 6 31 4 15 26 5 3 22 1 48 27 4
Deadman-4 - 15 37 9 6 41 8 1 39 15 27 2 9 39 7 46 35 6
Deadman-5 15 32 3 15 27 3 30 29 3
Deadman-6 - 14 40 6 18 38 6 32 39 6
Total1 7 1 0 3 7 2 299 20 3 45 12 2 52 24 4 3 3 1 83 12 2 168 23 3 176 27 3 284 20 2 1,120 21 3
Middle River
Fog Creek Fog-4 - 15 9 1 15 8 1 15 8 1 3 14 5 48 9 2
Unnamed Tributary 173.8 NA FA-173 (Stephan Lake Complex) 9 8 2 12 5 1 9 5 2 30 6 2
Devils Canyon upper extent
Chinook Creek Chinook-1 - 6 10 1 9 9 1 2 8 17 9 1
Chinook-2 - 3 3 0 3 5 1 1 3 3 3 1 10 8 1 9 8 1 29 7 1
Devils Canyon lower extent
Indian River NA FA-141 (Indian River) 24 21 18 17 9 3 30 20 14 9 72 11 80 24 13
Gold Creek NA - 1 14 6 10 4 12 12 2 5 12 2 24 12 3
Unnamed Tributary 115.4 NA FA-115 (Slough 6A) 15 3 1 6 1 0 3 1 0 24 2 1
Chase Creek NA - 3 4 1 3 10 3 6 7 2
Whiskers Creek NA FA-104 (Whiskers Slough) 3 3 0 42 7 1 51 8 1 42 7 1 21 6 1 159 7 1
Total1 6 3 0 0 NA NA 27 8 2 6 10 1 71 11 7 3 3 1 98 7 2 40 9 2 114 11 5 52 17 3 417 10 4
1Total number of measurements (n) and group mean (SD) for each mesohabitat type per River Segment. 2Total number of measurements (n) and group mean (SD) for each geomorphic reach.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 46 February 2014 Draft
Table 5.1-4. Mean (±SD) wetted width (m) of mesohabitats in Upper River and Middle River tributaries surveyed between August 3 and September 22, 2013.
Tributary Name Geomorphic Reach Focus Area Alcove Beaver Pond Boulder Riffle Cascade Glide Percolation Channel Pool Rapid Riffle Run All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
Oshetna River Oshetna-1 - 15 34 3 6 43 7 6 38 3 18 53 7 15 39 3 60 42 5
Oshetna-2 - 9 47 10 3 66 1 3 39 3 15 49 7
Oshetna-3 - 15 29 4 6 15 2 6 57 7 24 23 4 39 31 3 90 29 4
Black River Black-1 - 10 22 2 5 16 1 2 18 4 13 34 5 8 20 7 38 25 4
Black-2 - 21 20 5 3 18 2 9 14 2 18 17 2 51 18 3
Black-3 - 10 27 1 5 19 4 13 26 4 13 25 2 41 25 3
Goose Creek Goose-1 - 20 15 4 3 11 5 9 11 2 13 12 1 45 13 3
Goose-2 - 15 18 2 9 19 5 15 14 2 39 17 3
Goose-3 - 15 13 2 3 15 2 18 12 2 36 13 2
Proposed reservoir full pool
Jay Creek Jay-1 - 11 8 2 1 7 2 8 1 14 8 2
Jay-2 - 15 12 2 18 10 1 6 12 1 6 9 1 45 11 2
Jay-3 - 10 11 1 4 9 2 14 10 1
Jay-4 - 1 1 10 5 1 10 5 0 10 8 1 2 7 0 33 6 1
Kosina Creek Kosina-2 - 15 32 6 15 32 6
Tsisi Creek Tsisi-1 - 24 14 3 3 5 1 18 14 3 45 14 3
Tsisi-2 - 15 16 2 15 14 2 30 15 2
Unnamed Trib 206.3 UnnamedTrib206.3-1 - 15 5 1 18 3 1 3 3 0 3 3 0 39 4 1
UnnamedTrib206.3-3 - 3 1 0 6 1 0 3 1 0 12 1 0
Watana Creek Watana-1 - 3 15 1 6 12 2 12 20 3 6 13 2 27 16 3
Watana-2 - 6 11 2 3 7 1 6 10 3 6 9 1 9 10 1 30 10 2
Watana-3 - 6 1 0 39 12 1 9 9 0 9 15 2 21 8 1 84 10 1
Unnamed Watana Trib 1 Watana Trib-1 - 4 2 1 2 2 1 3 1 0 3 9 1 9 4 1 6 14 2 29 8 2 56 6 1
Unnamed Trib 194.8 UnnamedTrib194.8-3 - 3 5 2 6 3 1 6 4 1 34 4 1 9 3 1 3 3 1 18 3 1 79 4 1
UnnamedTrib194.8-4 - 18 3 1 12 3 1 30 3 1
Deadman Creek Deadman-3 - 18 28 5 6 19 5 6 29 5 15 25 6 3 18 2 48 25 5
Deadman-4 - 15 36 10 6 39 9 1 39 15 25 1 9 38 7 46 34 6
Deadman-5 15 30 3 15 25 2 30 27 3
Deadman-6 - 15 43 9 18 37 6 33 40 8
Total1 7 1 0 3 5 2 302 18 3 45 9 2 53 24 5 3 1 0 83 8 1 168 20 3 177 24 3 284 16 2 1,125 18 3
Middle River
Fog Creek Fog-4 - 15 7 1 15 6 1 15 7 1 3 9 3 48 7 1
Unnamed Tributary 173.8 NA FA-173 (Stephan Lake Complex) 9 4 1 12 3 1 12 5 2 33 4 1
Devils Canyon upper extent
Chinook Creek Chinook-1 - 6 8 1 9 8 1 2 7 17 8 1
Chinook-2 - 3 2 0 3 4 1 1 2 3 2 0 10 7 1 9 4 0 29 5 1
Devils Canyon lower extent
Indian River NA FA-141 (Indian River) 1 2 24 7 3 18 5 2 30 8 3 9 8 2 82 7 3
Gold Creek NA - 1 8 6 8 2 15 10 2 5 9 2 27 9 2
Unnamed Tributary 115.4 NA FA-115 (Slough 6A) 15 2 1 6 1 0 3 1 0 24 2 1
Chase Creek NA - 3 4 0 3 8 2 3 18 6 9 10 3
Whiskers Creek NA FA-104 (Whiskers Slough) 3 2 0 42 6 1 51 7 1 42 6 1 21 6 1 159 6 1
Total1 7 2 0 0 NA NA 27 6 1 6 8 1 71 6 1 3 2 0 99 5 1 40 7 1 123 7 2 52 6 1 428 6 1
1Total number of measurements (n) and group mean (SD) for each mesohabitat type per River Segment.
2Total number of measurements (n) and group mean (SD) for each geomorphic reach.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 47 February 2014 Draft
Table 5.1-5. Mean (±SD) bankfull depth (m) of mesohabitats in Upper River and Middle River tributaries surveyed between August 3 and September 22, 2013.
Tributary Name Geomorphic Reach Focus Area Alcove Beaver Pond Boulder Riffle Cascade Glide Percolation Channel Pool Rapid Riffle Run All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
Oshetna River Oshetna-1 - 15 1.1 0.1 6 1.3 0.2 12 0.8 0.2 6 1.2 0.2 39 1.1 0.1
Oshetna-2 -
Oshetna-3 - 15 1.0 0.1 3 1.0 0.2 18 0.8 0.1 18 0.9 0.0 54 0.9 0.1
Black River Black-1 - 10 0.5 0.0 5 0.8 0.2 2 2.1 0.4 13 0.5 0.1 8 0.7 0.1 38 0.7 0.1
Black-2 - 21 0.7 0.1 3 0.7 0.1 9 0.7 0.1 18 0.9 0.1 51 0.7 0.1
Black-3 - 10 0.6 0.0 5 0.8 0.1 13 0.7 0.1 13 0.7 0.0 41 0.7 0.1
Goose Creek Goose-1 - 20 0.7 0.2 3 1.2 0.3 8 0.6 0.2 13 0.8 0.2 44 0.7 0.2
Goose-2 - 15 0.8 0.1 9 0.6 0.1 15 0.9 0.1 39 0.8 0.1
Goose-3 - 15 0.6 0.1 3 0.5 0.1 18 0.7 0.1 36 0.7 0.1
Proposed reservoir full pool
Jay Creek Jay-1 - 11 0.6 0.1 1 1.1 2 0.9 0.3 14 0.7 0.2
Jay-2 - 15 0.7 0.1 18 0.8 0.1 6 0.6 0.1 6 0.8 0.1 45 0.7 0.1
Jay-3 - 10 0.6 0.1 4 0.7 0.2 14 0.6 0.1
Jay-4 - 1 0.3 10 0.6 0.1 10 0.9 0.1 10 0.4 0.1 2 0.5 0.1 33 0.6 0.1
Kosina Creek Kosina-2 - 15 1.1 0.1 15 1.1 0.1
Tsisi Creek Tsisi-1 - 24 0.7 0.1 3 0.9 0.1 18 0.8 0.1 45 0.7 0.1
Tsisi-2 - 15 0.6 0.0 15 0.7 0.1 30 0.7 0.0
Unnamed Trib 206.3 UnnamedTrib206.3-1 - 12 0.8 0.2 18 1.0 0.3 3 1.1 0.3 3 1.2 0.2 36 1.0 0.2
UnnamedTrib206.3-3 - 3 1.0 0.1 6 1.0 0.1 3 1.2 0.1 12 1.1 0.1
Watana Creek Watana-1 - 3 1.8 0.1 6 2.3 0.3 12 1.8 0.3 6 2.3 0.1 27 2.0 0.2
Watana-2 - 6 1.3 0.3 3 1.3 0.3 6 1.5 0.2 6 0.7 0.3 9 1.4 0.3 30 1.3 0.3
Watana-3 - 6 0.4 0.2 39 0.7 0.3 9 0.9 0.1 9 0.4 0.1 21 0.6 0.1 84 0.6 0.2
Unnamed Watana Trib 1 Watana Trib-1 - 4 0.7 0.0 2 0.5 0.1 3 0.8 0.3 3 1.3 0.2 9 1.0 0.1 6 1.0 0.3 28 0.9 0.1 55 0.9 0.1
Unnamed Trib 194.8 UnnamedTrib194.8-3 - 3 1.2 0.4 6 1.4 0.1 6 1.6 0.1 34 1.7 0.2 9 1.6 0.1 3 0.9 0.0 18 1.4 0.1 79 1.5 0.2
UnnamedTrib194.8-4 - 18 1.2 0.3 12 1.2 0.1 30 1.2 0.2
Deadman Creek Deadman-3 - 18 1.0 0.1 6 1.2 0.2 6 1.0 0.2 15 1.1 0.1 3 1.2 0.2 48 1.1 0.1
Deadman-4 - 15 0.9 0.1 6 1.2 0.3 1 0.8 15 1.0 0.1 9 0.9 0.1 46 1.0 0.1
Deadman-5 15 0.9 0.1 15 1.0 0.1 30 0.9 0.1
Deadman-6 - 15 0.9 0.1 18 0.8 0.3 33 0.9 0.2
Total1 7 0.4 0.2 3 1.2 0.4 299 0.8 0.1 45 1.0 0.2 50 0.9 0.2 3 0.8 0.3 83 1.4 0.2 146 1.0 0.1 162 0.8 0.1 250 0.9 0.1 1,048 0.9 0.1
Middle River
Fog Creek Fog-4 - 15 0.8 0.1 15 0.8 0.1 15 0.7 0.1 3 0.8 0.1 48 0.8 0.1
Unnamed Tributary 173.8 NA FA-173 (Stephan Lake
Complex) 9 0.7 0.1 12 0.9 0.2 9 0.6 0.1 30 0.7 0.1
Devils Canyon upper extent
Chinook Creek Chinook-1 - 6 0.7 0.1 9 0.6 0.1 2 0.8 17 0.7 0.1
Chinook-2 - 3 0.4 0.1 3 0.3 0.1 1 0.3 3 0.3 0.1 10 0.6 0.1 9 0.5 0.0 29 0.5 0.1
Devils Canyon lower extent
Indian River NA FA-141 (Indian River) 24 0.6 0.1 18 1.1 0.7 30 0.7 0.2 9 1.1 0.2 81 0.8 0.3
Gold Creek NA - 1 0.9 6 1.1 0.1 12 0.9 0.1 5 1.0 0.1 24 1.0 0.1
Unnamed Tributary 115.4 NA FA-115 (Slough 6A) 15 0.6 0.1 6 0.5 0.1 3 0.6 0.1 24 0.6 0.1
Chase Creek NA - 3 0.8 0.2 3 0.7 0.3 6 0.8 0.3
Whiskers Creek NA FA-104 (Whiskers
Slough) 3 0.6 0.0 42 0.7 0.1 48 1.0 0.2 42 0.6 0.1 21 0.8 0.1 156 0.8 0.1
Total1 6 0.5 0.0 0 NA NA 27 0.7 0.1 6 0.7 0.1 71 0.7 0.1 3 0.3 0.1 96 0.9 0.3 40 0.7 0.1 114 0.7 0.1 52 0.8 0.1 415 0.7 0.1
1Total number of measurements (n) and group mean (SD) for each mesohabitat type per River Segment. 2Total number of measurements (n) and group mean (SD) for each geomorphic reach.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 48 February 2014 Draft
Table 5.1-6. Mean (±SD) thalweg depth (m) of mesohabitats in Upper River and Middle River tributaries surveyed between August 3 and September 22, 2013.
Tributary Name Geomorphic Reach Focus Area Alcove Beaver Pond Boulder Riffle Cascade Glide Percolation Channel Pool Rapid Riffle Run All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
Oshetna River Oshetna-1 - 15 1.0 0.1 6 1.1 0.3 12 0.7 0.1 6 1.2 0.1 39 1.0 0.1
Oshetna-2 -
Oshetna-3 - 15 0.9 0.1 3 0.8 0.1 18 0.6 0.1 18 0.7 0.1 54 0.7 0.1
Black River Black-1 - 10 0.5 0.0 5 0.9 0.2 2 2.2 0.5 13 0.5 0.1 8 0.7 0.1 38 0.7 0.1
Black-2 - 21 0.6 0.1 3 0.8 0.2 9 0.6 0.1 18 0.9 0.1 51 0.7 0.1
Black-3 - 10 0.7 0.1 5 0.7 0.1 13 0.7 0.1 13 0.7 0.1 41 0.7 0.1
Goose Creek Goose-1 - 20 0.6 0.2 3 0.6 0.2 8 0.6 0.1 13 0.8 0.2 44 0.7 0.2
Goose-2 - 15 0.6 0.1 9 0.6 0.1 15 0.8 0.1 39 0.7 0.1
Goose-3 - 15 0.6 0.1 3 0.5 0.1 18 0.7 0.1 36 0.6 0.1
Proposed Reservoir Full Pool
Jay Creek Jay-1 - 11 0.5 0.1 1 0.8 2 0.8 0.1 14 0.6 0.1
Jay-2 - 15 0.6 0.0 18 0.6 0.1 6 0.5 0.1 6 0.7 0.1 45 0.6 0.1
Jay-3 - 10 0.5 0.0 4 0.7 0.1 14 0.6 0.1
Jay-4 - 1 0.3 10 0.5 0.1 10 0.9 0.1 10 0.4 0.1 2 0.7 0.2 33 0.6 0.1
Kosina Creek Kosina-2 - 15 1.0 0.1 15 1.0 0.1
Tsisi Creek Tsisi-1 - 24 0.5 0.1 3 0.7 0.2 18 0.7 0.1 45 0.6 0.1
Tsisi-2 - 15 0.5 0.1 15 0.7 0.1 30 0.6 0.1
Unnamed Trib 206.3 UnnamedTrib206.3-1 - 15 0.4 0.1 18 0.4 0.1 3 0.3 0.1 3 0.5 0.1 39 0.4 0.1
UnnamedTrib206.3-3 - 3 0.3 0.2 6 0.2 0.1 3 0.4 0.1 12 0.3 0.1
Watana Creek Watana-1 - 3 0.6 0.0 6 1.2 0.4 12 0.6 0.1 6 0.9 0.2 27 0.8 0.2
Watana-2 - 6 0.6 0.1 3 0.9 0.4 6 0.6 0.1 6 0.5 0.2 9 0.6 0.1 30 0.6 0.1
Watana-3 - 6 0.3 0.2 39 0.5 0.1 9 0.8 0.1 9 0.5 0.1 21 0.6 0.1 84 0.5 0.1
Unnamed Watana
Trib 1 Watana Trib-1 - 4 0.6 0.0 2 0.4 0.1 3 0.2 0.1 3 0.9 0.2 9 0.5 0.1 6 0.5 0.1 29 0.7 0.1 56 0.6 0.1
Unnamed Trib 194.8 UnnamedTrib194.8-3 - 3 0.9 0.4 6 0.7 0.2 6 0.7 0.1 34 1.0 0.2 9 0.7 0.1 3 0.3 0.1 18 0.6 0.1 79 0.8 0.2
UnnamedTrib194.8-4 - 18 0.6 0.3 12 0.4 0.0 30 0.5 0.2
Deadman Creek Deadman-3 - 18 1.0 0.1 6 1.0 0.2 6 0.7 0.1 15 0.9 0.2 3 1.4 0.4 48 0.9 0.1
Deadman-4 - 15 0.8 0.1 6 0.9 0.2 1 1.0 15 0.9 0.1 9 1.0 0.1 46 0.9 0.1
Deadman-5 15 0.7 0.1 15 0.9 0.1 30 0.8 0.1
Deadman-6 - 15 1.2 0.1 18 1.1 0.4 33 1.2 0.3
Total1 7 0.3 0.2 3 0.9 0.4 302 0.6 0.1 45 0.6 0.1 50 0.9 0.1 3 0.2 0.1 83 0.9 0.2 146 0.7 0.1 162 0.6 0.1 251 0.7 0.1 1,052 0.7 0.1
Middle River
Fog Creek Fog-4 - 15 0.6 0.1 15 0.6 0.1 15 0.6 0.1 3 0.6 0.1 48 0.6 0.1
Unnamed Tributary
173.8 NA FA-173 (Stephan Lake
Complex) 9 0.2 0.1 12 0.5 0.2 12 0.2 0.1 33 0.3 0.1
Devil's Canyon Upper Extent
Chinook Creek Chinook-1 - 6 0.7 0.1 9 0.6 0.1 2 0.7 17 0.6 0.1
Chinook-2 - 3 0.2 0.0 3 0.2 0.0 1 0.3 3 0.1 0.1 10 0.6 0.1 9 0.4 0.0 29 0.4 0.1
Devil's Canyon Lower Extent
Indian River NA FA-141 (Indian River) 24 0.3 0.1 18 0.7 0.5 30 0.3 0.1 9 0.5 0.3 81 0.4 0.2
Gold Creek NA - 1 0.7 6 0.7 0.1 15 0.6 0.1 5 0.7 0.1 27 0.7 0.1
Unnamed Tributary
115.4 NA FA-115 (Slough 6A) 15 0.3 0.1 6 0.1 0.0 3 0.2 0.0 24 0.2 0.1
Chase Creek NA - 3 0.5 0.2 3 0.8 0.6 3 0.2 0.1 9 0.5 0.3
Whiskers Creek NA FA-104 (Whiskers Slough) 3 0.3 0.1 42 0.4 0.1 51 0.8 0.3 42 0.2 0.1 21 0.4 0.1 159 0.5 0.2
Total1 6 0.2 0.0 0 NA NA 27 0.4 0.1 6 0.7 0.1 71 0.4 0.1 3 0.1 0.1 99 0.7 0.3 40 0.6 0.1 123 0.3 0.1 52 0.5 0.1 427 0.5 0.1
Notes:
1 Total number of measurements (n) and group mean (SD) for each mesohabitat type per River Segment.
2 Total number of measurements (n) and group mean (SD) for each geomorphic reach.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 49 February 2014 Draft
Table 5.1-7. Number of mesohabitats within macrohabitats measured for length, sum of length (m) surveyed, and composition by length in macrohabitats among geomorphic reaches and survey types in Upper River and Middle River mainstems surveyed between August 2 and
September 17, 2013.
Geomorphic
Reach Focus Area
Main Channel Split Main Channel Multi Split Main Channel Side Channel Tributary Mouth Side Slough Upland Slough Unconfirmed Macrohabitat3 All Measured Units2
n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length (m) & Percent n Length
Upper River
UR-3 NA 1 58 100 1 58
UR-4 NA 1 555 14 2 1,142 28 2 755 18 3 1,641 40 8 4,093
UR-5 NA 1 287 100 1 287
UR-6 NA 1 64 4 2 1,509 96 3 1,573
Total1 2 842 14 1 64 1 4 2,651 44 3 813 14 3 1,641 27 13 6,011
Middle River
MR-5 NA 1 966 100 1 966
MR-6 NA 1 1,113 20 4 1,173 21 1 202 4 4 1,295 23 3 1,750 31 1 156 3 14 5,690
MR-7 NA 2 235 12 1 741 37 3 892 45 2 127 6 8 1,995
MR-8 NA 1 608 29 3 1,217 58 2 287 14 6 2,112
Total1 4 1,956 18 1 966 9 7 2,390 22 4 1,230 11 7 2,187 20 5 1,877 17 1 156 1 29 10,762
Focus Areas
MR-1 FA-184 (Watana Dam) 2 616 100 2 616
MR-2 FA-173 (Stephan Lake Complex) 4 1,448 43 1 162 5 4 1,788 53 9 3,398
MR-6 FA-144 (Slough 21) 1 2,504 61 3 1,176 28 1 159 4 1 292 7 6 4,132
FA-141 (Indian River) 3 513 14 4 1,462 39 2 308 8 1 476 13 6 868 23 1 81 2 17 3,707
FA-138 (Gold Creek) 1 17 0 2 1,092 25 1 1,812 41 2 321 7 7 1,190 27 13 4,432
FA-128 (Slough 8A) 8 4,605 81 1 194 3 1 359 6 3 516 9 13 5,675
MR-7 FA-115 (Slough 6A) 4 921 24 1 341 9 4 1,951 50 2 681 17 11 3,894
FA-113 (Oxbow 1) 1 56 2 6 1,308 40 1 76 2 4 1,430 43 2 322 10 1 106 3 15 3,298
MR-8 FA-104 (Whiskers Slough) 1 183 6 8 1,739 54 7 1,164 36 1 162 5 17 3,248
Total1 5 752 2 10 2,229 7 5 1,479 5 28 12,388 38 3 832 3 21 8,070 25 19 4,300 13 12 2,350 7 103 32,399
Notes:
1 Total number of measurements (n), group sum, and group proportion for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), group sum, and group proportion for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
3 Quality control of data ongoing; these ground-based calls considered preliminary at the time of this report.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 50 February 2014 Draft
Table 5.1-8. Sample size and mean (±SD) of percent gradient measurements made among geomorphic reaches and survey types by macrohabitat in Upper River and Middle River mainstem surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Main Channel Split Main Channel Multi Split Channel Side Channel Tributary Mouth Side Slough Upland Slough Unconfirmed Macrohabitat3 All Measured Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 3 3.3 5.8 3 3.3 5.8
UR-4 NA 4 0.6 0.2 1 0.5 NA 1 0.8 NA 12 0.2 0.2 21 1.2 3.7 39 0.8 2.7
UR-5 NA 1 0.5 NA 1 0.5 NA
UR-6 NA 1 0.5 NA 1 2.0 NA 4 0.3 0.3 6 0.6 0.7
Total1 5 0.6 0.1 2 0.5 0.0 1 2.0 NA 5 0.4 0.4 15 0.8 2.5 21 1.2 3.7 49 0.9 2.8
Middle River
MR-2 NA 1 0.5 NA 1 0.5 NA
MR-3 NA
MR-5 NA 1 0.5 NA 1 0.5 NA
MR-6 NA 2 0.5 0.0 6 0.4 0.5 2 2.5 0.7 16 0.5 1.2 11 0.0 0.2 1 1.0 NA 38 0.5 1.0
MR-7 NA 2 0.3 0.4 4 0.4 0.3 13 0.1 0.3 3 0.0 0.0 22 0.2 0.3
MR-8 NA 1 0.5 NA 1 0.5 NA 18 0.7 0.6 5 0.4 0.6 25 0.6 0.6
Total1 6 0.4 0.2 2 0.5 0.0 24 0.6 0.6 11 0.8 1.0 29 0.3 0.9 14 0.0 0.1 1 1.0 NA 87 0.4 0.8
Focus Areas
MR-1 FA-184 (Watana Dam) 3 0.7 0.3 3 0.7 0.3
MR-2 FA-173 (Stephan Lake Complex) 8 0.0 0.0 2 1.5 0.7 11 0.1 0.2 21 0.2 0.5
MR-6 FA-144 (Slough 21) 2 0.5 0.0 1 0.5 NA 9 1.0 0.9 8 0.1 0.2 3 0.0 0.0 2 0.0 0.0 25 0.5 0.7
FA-141 (Indian River) 7 0.4 0.4 11 0.6 0.6 3 0.8 1.0 16 0.7 0.9 7 0.0 0.0 2 0.0 0.0 46 0.5 0.7
FA-138 (Gold Creek) 2 1.5 2.1 14 0.5 0.5 14 0.4 0.6 9 1.4 2.9 9 0.7 0.8 48 0.7 1.4
FA-128 (Slough 8A) 47 0.7 0.8 4 2.3 2.1 6 0.0 0.0 1 0.5 NA 58 0.7 1.0
MR-7 FA-115 (Slough 6A) 8 1.0 1.6 1 0.0 NA 22 0.2 0.5 7 0.5 0.9 38 0.4 0.9
FA-113 (Oxbow 1) 1 0.0 NA 11 0.9 0.6 1 0.5 NA 11 0.8 2.4 17 0.1 0.2 1 0.0 NA 42 0.5 1.3
MR-8 FA-104 (Whiskers Slough) 2 0.0 0.0 14 0.5 0.7 42 0.8 1.6 4 1.3 2.5 62 0.7 1.5
Total1 12 0.3 0.3 19 0.9 1.1 14 0.7 0.8 99 0.6 0.7 22 1.0 1.3 87 0.6 1.4 68 0.4 1.3 22 0.5 0.7 343 0.6 1.1
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
3 Quality control of data ongoing; these ground-based calls considered preliminary at the time of this report.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 51 February 2014 Draft
Table 5.1-9. Sample size and mean (±SD) of bankfull width measurements made among geomorphic reaches and survey types by macrohabitat in Upper River and Middle River mainstem surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Main Channel Split Main Channel Multi Split Main Channel Side Channel Tributary Mouth Side Slough Upland Slough Unconfirmed Macrohabitat3 All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 28 156 19 9 6 1 37 118 14
UR-4 NA 21 178 45 9 181 64 6 111 49 32 8 2 55 7 2 123 52 17
UR-5 NA 3 123 16 3 123 16
UR-6 NA 11 272 82 6 147 51 3 111 48 18 103 56 38 143 59
Total1 60 177 37 18 160 52 3 111 48 24 105 54 41 8 2 55 7 2 201 80 24
Middle River
MR-2 NA 3 127 4 3 127 4
MR-3 NA 12 163 19 6 99 16 18 131 18
MR-5 NA 3 115 11 3 115 11
MR-6 NA 9 191 36 24 81 28 9 47 8 47 10 4 28 15 3 3 82 46 120 42 12
MR-7 NA 9 242 7 3 157 105 15 43 4 39 16 5 9 5 1 75 53 8
MR-8 NA 3 402 41 3 94 41 32 58 19 4 50 13 42 81 21
Total1 36 215 21 15 113 38 56 67 22 28 45 7 86 13 4 37 12 2 3 82 46 261 58 13
Focus Areas
MR-1 FA-184 (Watana Dam) 6 164 35 9 64 7 15 89 14
MR-2 FA-173 (Stephan Lake Complex) 6 189 26 23 70 31 3 5 3 55 35 15 87 49 20
MR-6 FA-144 (Slough 21) 6 199 61 6 178 15 27 69 15 26 28 5 9 11 4 6 68 13 80 66 14
FA-141 (Indian River) 14 196 22 24 101 32 9 30 11 53 18 15 18 14 5 2 6 1 120 56 17
FA-138 (Gold Creek) 3 192 22 3 122 1 3 40 9 42 31 5 42 27 8 24 13 2 30 80 19 147 42 9
FA-128 (Slough 8A) 3 228 105 137 45 10 9 9 1 12 21 8 17 9 2 3 95 22 181 42 10
MR-7 FA-115 (Slough 6A) 18 163 24 3 33 11 65 7 3 15 17 1 101 36 7
FA-113 (Oxbow 1) 3 178 18 45 108 14 3 155 26 32 34 6 31 5 2 3 9 2 117 60 9
MR-8 FA-104 (Whiskers Slough) 3 27 6 3 187 29 45 53 8 123 11 2 9 14 3 183 25 4
Total1 44 181 34 69 126 17 33 109 27 295 50 11 65 16 13 293 23 6 173 9 3 59 57 13 1,031 45 10
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
3 Quality control of data ongoing; these ground-based calls considered preliminary at the time of this report.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 52 February 2014 Draft
Table 5.1-10. Sample size and mean (±SD) of wetted width measurements made among geomorphic reaches and survey types by macrohabitats in Upper River and Middle River mainstem surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Main Channel Split Main Channel Multi Split Main Channel Side Channel Tributary Mouth Side Slough Upland Slough Unconfirmed Macrohabitat3 All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 19 151 19 6 3 1 25 110 14
UR-4 NA 14 151 27 6 100 28 4 63 20 20 8 2 37 6 2 81 41 9
UR-5 NA 2 109 3 2 109 3
UR-6 NA 9 224 49 4 129 26 2 28 9 12 66 14 27 102 22
Total1 42 159 26 12 111 23 2 28 9 16 65 15 26 6 1 37 6 2 135 64 12
Middle River
MR-2 NA 2 111 6 2 111 6
MR-3 NA 10 145 11 4 88 16 14 116 14
MR-5 NA 2 116 7 2 116 7
MR-6 NA 6 185 35 16 53 15 6 36 6 26 5 3 19 6 2 2 39 26 75 33 9
MR-7 NA 6 162 5 2 78 13 10 32 4 22 8 3 6 3 1 46 36 4
MR-8 NA 2 350 57 2 84 5 36 30 9 10 24 4 50 44 10
Total1 26 179 20 10 91 11 52 37 11 26 30 5 48 6 3 25 5 1 2 39 26 189 42 8
Focus Areas
MR-1 FA-184 (Watana Dam) 5 163 37 6 48 3 11 77 11
MR-2 FA-173 (Stephan Lake Complex) 5 188 24 19 10 3 6 6 3 37 11 2 67 16 3
MR-6 FA-144 (Slough 21) 4 215 66 4 150 11 18 27 9 16 9 3 4 8 3 4 30 5 50 45 11
FA-141 (Indian River) 12 77 10 21 82 27 6 19 7 54 5 2 16 10 3 6 3 1 115 33 9
FA-138 (Gold Creek) 2 191 26 2 117 1 2 23 6 28 17 2 28 13 3 16 5 1 20 48 13 98 26 5
FA-128 (Slough 8A) 2 204 16 96 27 6 4 7 1 4 10 1 11 6 1 2 89 31 119 28 6
MR-7 FA-115 (Slough 6A) 16 106 9 2 27 9 42 5 2 10 9 2 70 29 4
FA-113 (Oxbow 1) 4 96 19 30 82 10 2 19 1 19 16 5 28 6 2 2 7 4 85 40 6
MR-8 FA-104 (Whiskers Slough) 4 11 2 2 198 9 29 32 7 68 7 1 8 10 1 111 17 3
Total1 38 116 21 50 96 9 27 88 23 204 25 6 64 6 2 174 10 2 125 6 2 44 31 9 726 29 6
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
3 Quality control of data ongoing; these ground-based calls considered preliminary at the time of this report.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 53 February 2014 Draft
Table 5.1-11. Sample size and mean (±SD) of bankfull depth measurements made among geomorphic reaches and survey types by macrohabitats in Upper River and Middle River mainstem surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Main Channel Split Main Channel Multi Split Main Channel Side Channel Tributary Mouth Side Slough Upland Slough Unconfirmed Macrohabitat3 All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 22 2.6 0.4 8 0.5 0.1 30 2.1 0.3
UR-4 NA 21 2.3 0.6 9 1.0 0.1 6 1.1 0.1 32 0.5 0.0 52 0.7 0.2 120 1.0 0.2
UR-5 NA 3 1.3 0.2 3 1.3 0.2
UR-6 NA 11 1.8 0.6 6 1.6 0.5 3 1.0 0.2 18 1.0 0.2 38 1.3 0.3
Total1 54 2.4 0.5 18 1.3 0.2 3 1.0 0.2 24 1.0 0.2 40 0.5 0.1 52 0.7 0.2 191 1.2 0.2
Middle River
MR-2 NA 3 3.4 0.2 3 3.4 0.2
MR-3 NA 12 2.2 0.2 6 2.0 0.2 18 2.1 0.2
MR-5 NA 3 3.0 0.3 3 3.0 0.3
MR-6 NA 9 2.5 0.3 23 1.1 0.3 9 1.3 0.2 36 1.2 0.2 29 1.0 0.1 3 2.2 0.3 109 1.3 0.2
MR-7 NA 6 1.7 0.1 3 2.2 0.2 15 0.9 0.1 33 0.8 0.2 9 0.7 0.1 66 0.9 0.1
MR-8 NA 3 1.9 0.2 3 1.6 0.2 31 1.0 0.1 4 0.9 0.4 41 1.1 0.2
Total1 33 2.3 0.2 15 2.2 0.2 54 1.1 0.2 28 1.0 0.1 69 1.0 0.2 38 0.9 0.1 3 2.2 0.3 240 1.2 0.2
Focus Areas
MR-1 FA-184 (Watana Dam) 6 2.3 0.5 8 1.5 0.3 14 1.7 0.4
MR-2 FA-173 (Stephan Lake Complex) 6 2.2 0.3 29 0.8 0.1 3 0.4 0.1 56 0.7 0.2 94 0.8 0.2
MR-6 FA-144 (Slough 21) 6 2.9 0.2 6 2.7 0.3 24 1.2 0.1 24 1.2 0.1 6 2.5 2.8 6 1.4 0.1 72 1.6 0.4
FA-141 (Indian River) 8 1.8 0.1 12 1.7 0.1 9 0.7 0.2 54 0.7 0.3 17 1.1 0.2 3 0.7 0.1 103 1.0 0.2
FA-138 (Gold Creek) 1 2.6 1 2.5 3 0.7 0.0 41 0.9 0.2 41 1.0 0.4 24 1.5 0.1 28 1.7 0.4 139 1.3 0.3
FA-128 (Slough 8A) 3 2.1 0.5 129 1.3 0.2 6 0.7 0.0 6 0.8 0.1 18 0.8 0.1 162 1.2 0.2
MR-7 FA-115 (Slough 6A) 19 2.2 0.2 2 1.9 0.1 63 0.7 0.1 9 0.8 0.1 93 1.0 0.2
FA-113 (Oxbow 1) 6 1.8 0.2 45 1.7 0.3 3 0.9 0.1 28 1.0 0.6 26 0.5 0.1 3 0.8 0.3 111 1.2 0.3
MR-8 FA-104 (Whiskers Slough) 3 0.8 0.1 3 2.2 0.1 39 1.3 0.1 99 0.7 0.1 9 1.2 0.3 153 0.9 0.1
Total1 39 2.0 0.2 68 1.9 0.2 21 1.8 0.2 282 1.2 0.2 63 0.6 0.2 256 0.8 0.2 163 0.9 0.2 49 1.4 0.3 941 1.1 0.2
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
3 Quality control of data ongoing; these ground-based calls considered preliminary at the time of this report.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 54 February 2014 Draft
Table 5.1-12. Sample size and mean (±SD) of thalweg depth measurements made among geomorphic reaches and survey types by macrohabitats in Upper River and Middle River mainstem surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Main Channel Split Main Channel Multi Split Main Channel Side Channel Tributary Mouth Side Slough Upland Slough Unconfirmed Macrohabitat3 All Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 22 3.1 0.6 9 0.3 0.1 31 2.4 0.4
UR-4 NA 20 4.0 1.0 3 1.3 0.3 3 0.9 0.0 32 0.4 0.1 56 0.6 0.2 114 1.1 0.3
UR-5 NA 3 1.9 0.3 3 1.9 0.3
UR-6 NA 11 2.6 1.2 6 1.9 0.4 3 0.5 0.2 3 0.6 0.1 23 1.7 0.6
Total1 53 3.4 0.8 12 1.8 0.4 3 0.5 0.2 6 0.8 0.1 41 0.4 0.1 56 0.6 0.2 171 1.5 0.3
Middle River
MR-2 NA 3 3.6 0.3 3 3.6 0.3
MR-3 NA 12 2.7 0.2 6 2.3 0.1 18 2.5 0.2
MR-5 NA 3 2.7 0.9 3 2.7 0.9
MR-6 NA 9 2.4 0.3 18 1.8 0.2 9 0.8 0.1 32 0.3 0.1 20 0.4 0.1 3 1.0 0.5 91 0.9 0.1
MR-7 NA 9 1.7 0.4 3 1.7 0.4 15 0.5 0.1 33 0.3 0.1 9 0.3 0.1 69 0.6 0.2
MR-8 NA 3 3.2 0.2 3 1.1 0.6 54 0.5 0.1 15 0.5 0.2 75 0.6 0.2
Total1 36 2.5 0.3 15 2.0 0.4 72 0.8 0.1 39 0.6 0.1 65 0.3 0.1 29 0.4 0.1 3 1.0 0.5 259 0.9 0.2
Focus Areas
MR-1 FA-184 (Watana Dam) 6 2.9 0.3 9 1.6 0.4 15 1.9 0.3
MR-2 FA-173 (Stephan Lake Complex) 6 2.8 0.5 29 0.3 0.1 6 0.2 0.1 56 0.7 0.3 97 0.6 0.3
MR-6 FA-144 (Slough 21) 6 2.4 0.2 6 2.2 0.2 24 0.6 0.1 24 0.4 0.1 6 0.7 0.2 6 0.6 0.1 72 0.8 0.1
FA-141 (Indian River) 15 1.1 0.1 17 1.1 0.2 9 0.7 0.3 54 0.3 0.2 22 0.9 0.2 6 0.3 0.2 123 0.7 0.2
FA-138 (Gold Creek) 1 2.8 1 2.0 6 0.5 0.1 41 0.4 0.1 42 0.5 0.3 24 0.3 0.1 30 0.8 0.2 145 0.5 0.2
FA-128 (Slough 8A) 3 2.6 1.0 135 0.7 0.2 6 0.3 0.1 6 0.6 0.1 18 0.5 0.2 168 0.7 0.2
MR-7 FA-115 (Slough 6A) 24 1.6 0.3 2 1.1 0.1 63 0.5 0.2 15 0.3 0.1 104 0.8 0.2
FA-113 (Oxbow 1) 6 1.4 0.5 45 1.3 0.2 3 0.6 0.1 27 0.3 0.2 41 0.3 0.1 3 0.4 0.3 125 0.7 0.2
MR-8 FA-104 (Whiskers Slough) 6 0.4 0.1 3 1.9 0.3 42 0.7 0.2 100 0.3 0.1 12 0.7 0.3 163 0.5 0.1
Total1 49 1.6 0.3 73 1.5 0.3 29 1.2 0.2 292 0.6 0.2 66 0.3 0.2 257 0.5 0.2 186 0.5 0.2 60 0.6 0.2 1,012 0.7 0.2
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
3 Quality control of data ongoing; these ground-based calls considered preliminary at the time of this report.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 55 February 2014 Draft
Table 5.1-13. Number of mesohabitats measured for length, sum of length (m) surveyed, and composition by length of mesohabitats among geomorphic reaches and survey types in Upper River and Middle River mainstems surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Pool Riffle Glide Run Backwater Beaver Complex Clearwater Plume Dry Channel No Mesohabitat Recorded All Measured Units2
n Length & Proportion n Length & Proportion n Length & Proportion n Length & Proportion n Length & Proportion n Length & Proportion n Length & Proportion n Length & Proportion n Length & Proportion n Length
Upper River
UR-3 NA 1 41 0.71 1 6 0.10 1 11 0.19 3 58
UR-4 NA 13 1,150 0.28 9 1,554 0.38 10 549 0.13 2 581 0.14 3 258 0.06 37 4,093
UR-5 NA 1 287 1.00 1 287
UR-6 NA 2 155 0.10 2 808 0.51 3 610 0.39 7 1,573
Total1 14 1,191 0.20 12 1,715 0.29 13 1,368 0.23 6 1,478 0.25 3 258 0.04 48 6,011
Middle River
MR-5 NA 1 966 1.00 1 966
MR-6 NA 10 877 0.15 8 500 0.09 3 408 0.07 4 1,624 0.29 8 1,435 0.25 5 539 0.09 3 308 0.05 41 5,690
MR-7 NA 1 7 0.00 4 251 0.13 6 942 0.47 1 210 0.11 3 206 0.10 5 139 0.07 1 25 0.01 2 215 0.11 23 1,995
MR-8 NA 5 99 0.05 6 325 0.15 7 875 0.41 4 813 0.38 22 2,112
Total1 16 983 0.09 18 1,075 0.10 16 2,225 0.21 10 3,613 0.34 3 206 0.02 13 1,574 0.15 1 25 0.00 7 754 0.07 3 308 0.03 87 10,762
Focus Areas
MR-1 FA-184 (Watana
Dam) 1 263 0.43 2 353 0.57 3 616
MR-2 FA-173 (Stephan
Lake Complex) 5 647 0.19 6 745 0.22 14 1,886 0.56 2 121 0.04 27 3,398
MR-6 FA-144 (Slough 21) 2 187 0.05 6 1,688 0.41 4 649 0.16 1 236 0.06 2 292 0.07 6 734 0.18 3 346 0.08 24 4,132
FA-141 (Indian River) 12 728 0.20 9 891 0.24 7 264 0.07 5 873 0.24 1 58 0.02 3 442 0.12 5 452 0.12 42 3,707
FA-138 (Gold Creek) 10 832 0.19 14 906 0.20 10 673 0.15 5 712 0.16 3 165 0.04 5 1,085 0.24 2 59 0.01 49 4,432
FA-128 (Slough 8A) 18 1,654 0.29 16 1,204 0.21 8 1,015 0.18 8 1,382 0.24 1 66 0.01 4 262 0.05 2 93 0.02 57 5,675
MR-7 FA-115 (Slough 6A) 12 966 0.25 6 131 0.03 2 40 0.01 4 847 0.22 3 443 0.11 6 1,048 0.27 3 419 0.11 36 3,894
FA-113 (Oxbow 1) 9 750 0.23 7 592 0.18 4 221 0.07 4 678 0.21 5 705 0.21 3 352 0.11 32 3,298
MR-8 FA-104 (Whiskers
Slough) 23 1,365 0.42 11 783 0.24 2 490 0.15 1 89 0.03 2 75 0.02 2 77 0.02 8 370 0.11 49 3,248
Total1 91 7,128 0.22 76 7,202 0.22 53 5,590 0.17 28 4,817 0.15 17 1,803 0.06 20 3,309 0.10 7 529 0.02 25 1,929 0.06 2 93 0.00 319 32,399
Notes:
1 Total number of measurements (n), group sum, and group proportion for Focus Area and non-Focus Area mesohabitats per River Segment.
2 Total number of measurements (n), group sum, and group proportion for Focus Area and non-Focus Area mesohabitats per Geomorphic Reach.
INITIAL STUDY REPORT CHARACTERIZATION AND MAPPING OF AQUATIC HABITATS (9.9)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 56 February 2014 Draft
Table 5.1-14. Sample size and mean (±SD) of percent gradient measurements made among geomorphic reaches and survey types in mesohabitats in Upper River and Middle River mainstems surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Pool Riffle Glide Run Backwater Beaver Complex Clearwater Plume Dry Channel No Mesohabitat Recorded All Measured Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 1 0.0 NA 1 10.0 NA 1 0.0 NA 3 3.3 5.8
UR-4 NA 13 0.1 0.1 9 1.1 1.0 12 0.3 0.2 3 0.4 0.2 2 8.5 12.0 39 0.8 2.7
UR-5 NA 1 0.5 NA 1 0.5 NA
UR-6 NA 2 1.3 1.1 1 0.0 NA 3 0.3 0.3 6 0.6 0.7
Total1 14 0.1 0.1 12 1.8 2.7 14 0.2 0.2 7 0.4 0.2 2 8.5 12.0 49 0.9 2.8
Middle River
MR-2 NA 1 0.5 NA 1 0.5 NA
MR-3 NA
MR-5 NA 1 0.5 NA 1 0.5 NA
MR-6 NA 10 0.0 0.0 7 1.6 1.8 3 0.2 0.3 4 0.5 0.4 8 0.0 0.0 3 0.3 0.3 3.0 1.0 1.0 38 0.5 1.0
MR-7 NA 1 0.0 NA 4 0.5 0.4 5 0.1 0.2 1 0.0 NA 3 0.0 0.0 5 0.1 0.2 1 0.5 NA 2 0.0 0.0 22 0.2 0.3
MR-8 NA 5 0.0 0.0 6 1.3 0.6 8 0.4 0.4 6 0.8 0.3 25 0.6 0.6
Total1 16 0.0 0.0 18 1.2 1.2 16 0.2 0.3 12 0.6 0.4 3 0.0 0.0 13 0.0 0.1 1 0.5 NA 5 0.2 0.3 3.0 1.0 1.0 87 0.4 0.8
Focus Areas
MR-1 FA-184 (Watana Dam) 1 1.0 NA 2 0.5 0.0 3 0.7 0.3
MR-2 FA-173 (Stephan Lake Complex) 5 0.0 0.0 5 0.6 0.9 11 0.1 0.2 21 0.2 0.5
MR-6 FA-144 (Slough 21) 2 0.0 0.0 8 1.2 0.7 4 0.1 0.3 2 0.8 0.4 2 0.0 0.0 6 0.0 0.0 1 0.0 NA 25 0.5 0.7
FA-141 (Indian River) 11 0.0 0.0 11 1.0 1.0 7 0.7 0.8 9 0.6 0.2 1 0.0 NA 3 0.0 0.0 4 0.3 0.5 46 0.5 0.7
FA-138 (Gold Creek) 11 0.0 0.0 13 1.3 0.6 10 0.5 0.7 5 0.5 0.4 3 0.0 0.1 5 0.0 0.0 1 9.0 NA 48 0.7 1.4
FA-128 (Slough 8A) 18 0.0 0.0 17 1.6 1.0 9 0.4 1.0 9 0.6 0.7 1 0.0 NA 2 2.0 0.0 2.0 0.5 0.7 58 0.7 1.0
MR-7 FA-115 (Slough 6A) 12 0.0 0.0 7 1.4 1.7 3 0.0 0.0 4 0.4 0.3 3 0.0 0.0 6 0.2 0.3 3 1.3 0.8 38 0.4 0.9
FA-113 (Oxbow 1) 12 0.7 2.3 7 1.1 0.6 8 0.2 0.2 6 0.4 0.2 5 0.0 0.0 1 0.0 NA 3 0.3 0.3 42 0.5 1.3
MR-8 FA-104 (Whiskers Slough) 32 0.0 0.0 13 1.9 1.4 4 0.1 0.3 1 0.5 NA 2 0.0 0.0 2 0.0 0.0 8 2.3 2.6 62 0.7 1.5
Total1 103 0.1 0.8 82 1.3 1.1 58 0.3 0.6 36 0.5 0.4 17 0.0 0.0 21 0.0 0.2 6 0.2 0.4 18 2.0 2.6 2.0 0.5 0.7 343 0.6 1.1
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area macrohabitats per Geomorphic Reach.
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Table 5.1-15. Sample size and mean (±SD) of bankfull width measurements made among geomorphic reaches and survey types in mesohabitats in Upper River and Middle River mainstems surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Pool Riffle Glide Run Backwater Beaver Complex Clearwater Plume4 Dry Channel3 No Mesohabitat Recorded All Measured Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 3 8 0 20 142 20 3 9 2 11 138 13 37 118 14
UR-4 NA 35 8 2 39 95 30 34 36 10 12 113 35 3 2 1 123 52 17
UR-5 NA 3 123 16 3 123 16
UR-6 NA 6 104 36 12 164 94 20 141 40 38 143 59
Total1 38 8 2 65 109 28 49 64 30 46 131 30 3 2 1 201 80 24
Middle River
MR-2 NA 3 127 4 3 127 4
MR-3 NA 3 148 20 15 125 17 18 131 18
MR-5 NA 3 115 11 3 115 11
MR-6 NA 25 19 7 26 52 17 9 18 5 18 136 31 22 11 2 11 11 4 9 43 17 120 42 12
MR-7 NA 3 4 1 18 77 20 18 30 5 3 313 10 9 11 3 15 10 5 3 215 3 6 29 9 75 53 8
MR-8 NA 3 15 1 9 54 7 20 58 15 10 164 48 42 81 21
Total1 31 17 5 59 68 16 47 40 9 49 152 30 9 11 3 37 11 3 3 215 3 17 17 5 9 43 17 261 58 13
Focus Areas
MR-1 FA-184 (Watana Dam) 3 47 3 6 73 10 6 164 35 15 89 14
MR-2 FA-173 (Stephan Lake Complex) 16 62 17 18 65 37 53 40 14 87 49 20
MR-6 FA-144 (Slough 21) 6 17 4 24 86 14 12 65 16 9 184 45 6 68 13 18 13 4 5 18 3 80 66 14
FA-141 (Indian River) 26 12 4 31 69 16 24 21 18 27 114 33 9 16 4 3 185 30 120 56 17
FA-138 (Gold Creek) 30 22 5 42 36 6 30 46 14 21 94 11 9 26 6 15 34 9 147 42 9
FA-128 (Slough 8A) 54 25 7 54 49 8 30 55 17 26 61 16 2 7 3 9 17 9 6 39 5 181 42 10
MR-7 FA-115 (Slough 6A) 27 12 3 18 53 5 9 72 9 12 114 23 9 16 5 17 9 4 9 14 2 101 36 7
FA-113 (Oxbow 1) 26 22 4 27 86 13 19 96 14 21 81 10 15 26 4 9 17 5 117 60 9
MR-8 FA-104 (Whiskers Slough) 93 15 2 39 30 5 15 75 12 6 81 7 6 12 3 24 11 3 183 25 4
Total1 278 21 5 256 55 11 198 53 15 128 98 21 47 26 5 59 17 5 3 185 30 56 14 4 6 39 5 1,031 45 10
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per Geomorphic Reach.
3 Bankfull width in Dry channels indicates the mean bankfull width of intermittent or standing puddled water in the otherwise uncategorized mesohabitat unit.
4 Bankfull width of Cleawater Plume indicates the bankfull width of the mesohabitat into which the Clearwater Plume flows.
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Table 5.1-16. Sample size and mean (±SD) of wetted width measurements made among geomorphic reaches and survey types in mesohabitats in Upper River and Middle River mainstems surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Pool Riffle Glide Run Backwater Beaver Complex Clearwater Plume3 No Mesohabitat Recorded All Measured Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 2 5 2 14 137 20 2 1 1 7 127 12 25 110 14
UR-4 NA 22 8 2 28 64 18 23 28 5 8 88 6 81 41 9
UR-5 NA 2 109 3 2 109 3
UR-6 NA 4 66 11 8 103 20 15 117 29 27 102 22
Total1 24 8 2 46 84 18 33 44 8 32 110 16 135 64 12
Middle River
MR-2 NA 2 111 6 2 111 6
MR-3 NA 2 127 4 12 113 17 14 116 14
MR-5 NA 2 116 7 2 116 7
MR-6 NA 19 7 4 18 39 11 6 9 1 12 113 24 14 8 2 6 21 10 75 33 9
MR-7 NA 2 4 1 12 54 4 12 20 3 2 309 12 6 5 1 10 10 4 2 3 1 46 36 4
MR-8 NA 10 8 1 12 28 6 16 40 12 12 94 18 50 44 10
Total1 31 7 3 46 47 7 34 27 7 40 118 19 6 5 1 24 9 3 2 3 1 6 21 10 189 42 8
Focus Areas
MR-1 FA-184 (Watana Dam) 2 38 4 4 54 2 5 163 37 11 77 11
MR-2 FA-173 (Stephan Lake Complex) 12 13 3 18 9 2 37 20 3 67 16 3
MR-6 FA-144 (Slough 21) 4 6 1 16 48 10 8 31 6 6 163 44 4 30 5 12 9 4 50 45 11
FA-141 (Indian River) 27 22 4 25 22 5 24 7 3 19 113 31 4 2 0 6 13 1 10 3 1 115 33 9
FA-138 (Gold Creek) 20 11 3 28 18 3 20 24 9 14 77 9 6 18 4 10 15 4 98 26 5
FA-128 (Slough 8A) 40 14 3 36 29 6 20 43 9 18 46 12 1 3 4 19 1 119 28 6
MR-7 FA-115 (Slough 6A) 24 9 3 14 42 5 6 66 4 8 88 6 6 13 4 12 4 2 70 29 4
FA-113 (Oxbow 1) 24 14 3 18 58 5 20 50 7 14 66 13 9 10 5 85 40 6
MR-8 FA-104 (Whiskers Slough) 62 9 1 25 16 4 12 56 5 4 69 13 4 7 2 4 3 0 111 17 3
Total1 213 12 3 182 28 5 151 33 6 88 85 18 34 13 4 40 9 3 14 3 1 4 19 1 726 29 6
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per Geomorphic Reach.
3 Wetted width of Cleawater Plume indicates the mean width of clear (non-turbid) water in the Clearwater Plume.
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Table 5.1-17. Sample size and mean (±SD) of bankfull depth measurements made among geomorphic reaches and survey types in mesohabitats in Upper River and Middle River mainstems surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Pool Riffle Glide Run Backwater Beaver Complex Clearwater Plume3 No Mesohabitat Recorded All Measured Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 3 1.1 0.3 18 1.9 0.3 2 0.4 0.1 7 3.0 0.4 30 2.1 0.3
UR-4 NA 35 0.9 0.2 39 1.2 0.2 34 0.5 0.1 12 1.5 0.6 120 1.0 0.2
UR-5 NA 3 1.3 0.2 3 1.3 0.2
UR-6 NA 6 1.0 0.2 12 1.4 0.4 20 1.2 0.3 38 1.3 0.3
Total1 38 1.0 0.2 63 1.4 0.2 48 0.7 0.2 42 1.8 0.4 191 1.2 0.2
Middle River
MR-2 NA 3 3.4 0.2 3 3.4 0.2
MR-3 NA 3 2.1 0.3 15 2.1 0.2 18 2.1 0.2
MR-5 NA 3 3.0 0.3 3 3.0 0.3
MR-6 NA 25 1.1 0.3 27 1.4 0.2 8 0.8 0.1 18 1.5 0.2 22 1.1 0.1 9 1.5 0.2 109 1.3 0.2
MR-7 NA 3 0.9 0.2 18 1.4 0.1 18 0.9 0.3 9 0.8 0.1 15 0.6 0.1 3 0.5 0.0 66 0.9 0.1
MR-8 NA 3 0.7 0.1 9 0.7 0.0 21 1.2 0.2 8 1.4 0.1 41 1.1 0.2
Total1 31 1.1 0.3 60 1.4 0.2 47 1.0 0.2 44 1.8 0.2 9 0.8 0.1 37 0.9 0.1 3 0.5 0.0 9 1.5 0.2 240 1.2 0.2
Focus Areas
MR-1 FA-184 (Watana Dam) 2 1.0 0.1 6 1.7 0.5 6 2.3 0.5 14 1.7 0.4
MR-2 FA-173 (Stephan Lake Complex) 18 1.2 0.1 21 0.5 0.1 55 0.7 0.2 94 0.8 0.2
MR-6 FA-144 (Slough 21) 6 1.1 0.1 24 1.5 0.2 9 1.5 0.1 9 2.5 0.2 6 1.4 0.1 18 1.5 1.0 72 1.6 0.4
FA-141 (Indian River) 26 0.9 0.4 28 0.8 0.1 24 0.6 0.1 13 1.9 0.1 9 1.3 0.3 3 0.8 0.1 103 1.0 0.2
FA-138 (Gold Creek) 29 1.1 0.3 42 1.0 0.1 30 1.1 0.1 15 1.9 0.2 9 1.6 0.7 14 1.7 0.7 139 1.3 0.3
FA-128 (Slough 8A) 53 1.2 0.3 48 0.9 0.1 27 1.2 0.2 25 1.6 0.3 3 0.8 0.2 6 1.7 0.3 162 1.2 0.2
MR-7 FA-115 (Slough 6A) 30 0.8 0.1 17 1.0 0.1 9 2.2 0.2 11 1.2 0.2 8 1.0 0.1 18 0.8 0.2 93 1.0 0.2
FA-113 (Oxbow 1) 30 1.0 0.6 27 1.5 0.2 20 1.3 0.2 21 1.1 0.2 13 0.6 0.1 111 1.2 0.3
MR-8 FA-104 (Whiskers Slough) 91 0.8 0.1 38 0.9 0.1 15 1.3 0.1 6 1.3 0.1 3 0.8 0.0 153 0.9 0.1
Total1 283 0.964 0.238 247 0.992 0.136 195 1.085 0.183 106 1.662 0.21 42 1.023 0.231 59 1.3 0.6 3 0.8 0.1 6 1.7 0.3 941 1.1 0.2
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per Geomorphic Reach.
3 Bankfull depth of Cleawater Plume indicates the mean bankfull depth of clear (non-turbid) water in the Clearwater Plume as referenced by the bankfull width of the mesohabitat in which it flows.
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Table 5.1-18. Sample size and mean (±SD) of thalweg depth measurements made among geomorphic reaches and survey types in mesohabitats in Upper River and Middle River mainstems surveyed between August 2 and September 17, 2013.
Geomorphic Reach Focus Area
Pool Riffle Glide Run Backwater Beaver Complex Clearwater Plume3 No Mesohabitat Recorded All Measured Units2
n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD) n Mean(SD)
Upper River
UR-3 NA 3 0.8 0.3 18 2.7 0.6 3 0.1 0.0 7 2.9 0.3 31 2.4 0.4
UR-4 NA 35 0.8 0.2 33 1.6 0.4 35 0.6 0.1 11 2.7 0.7 114 1.1 0.3
UR-5 NA 3 1.9 0.3 3 1.9 0.3
UR-6 NA 3 0.5 0.2 6 2.1 1.1 14 1.8 0.4 23 1.7 0.6
Total1 38 0.8 0.2 54 1.9 0.4 44 0.7 0.3 35 2.5 0.5 171 1.5 0.3
Middle River
MR-2 NA 3 3.6 0.3 3 3.6 0.3
MR-3 NA 3 2.8 0.2 15 2.4 0.1 18 2.5 0.2
MR-5 NA 3 2.7 0.9 3 2.7 0.9
MR-6 NA 21 0.4 0.2 27 0.9 0.1 6 0.2 0.1 15 2.3 0.2 13 0.6 0.1 9 0.6 0.3 91 0.9 0.1
MR-7 NA 3 0.5 0.2 18 1.0 0.2 18 0.4 0.1 3 1.5 0.4 9 0.3 0.1 15 0.4 0.1 3 0.2 0.1 69 0.6 0.2
MR-8 NA 15 0.3 0.1 18 0.4 0.1 24 0.7 0.2 18 1.1 0.2 75 0.6 0.2
Total1 39 0.4 0.1 69 1.0 0.2 48 0.5 0.2 54 1.8 0.2 9 0.3 0.1 28 0.5 0.1 3 0.2 0.1 9 0.6 0.3 259 0.9 0.2
Focus Areas
MR-1 FA-184 (Watana Dam) 3 1.2 0.2 6 1.8 0.4 6 2.9 0.3 15 1.9 0.3
MR-2 FA-173 (Stephan Lake Complex) 18 1.3 0.4 24 0.2 0.1 55 0.5 0.3 97 0.6 0.3
MR-6 FA-144 (Slough 21) 6 0.4 0.2 24 0.8 0.1 9 0.6 0.1 9 1.9 0.2 6 0.6 0.1 18 0.6 0.2 72 0.8 0.1
FA-141 (Indian River) 32 0.5 0.3 28 0.5 0.1 24 0.3 0.1 13 1.6 0.3 5 0.6 0.3 9 1.4 0.3 12 0.3 0.1 123 0.7 0.2
FA-138 (Gold Creek) 32 0.5 0.3 42 0.3 0.1 30 0.3 0.1 17 1.2 0.2 9 0.6 0.2 15 0.8 0.4 145 0.5 0.2
FA-128 (Slough 8A) 60 0.6 0.2 48 0.3 0.1 27 0.8 0.3 25 1.6 0.4 3 0.6 0.3 5 0.3 0.1 168 0.7 0.2
MR-7 FA-115 (Slough 6A) 36 0.5 0.2 21 0.5 0.1 9 2.6 0.2 12 0.8 0.3 8 0.8 0.1 18 0.6 0.2 104 0.8 0.2
FA-113 (Oxbow 1) 35 0.5 0.2 27 1.2 0.3 30 0.7 0.1 21 0.9 0.2 12 0.3 0.1 125 0.7 0.2
MR-8 FA-104 (Whiskers Slough) 91 0.4 0.2 36 0.5 0.1 18 0.7 0.2 6 0.9 0.2 6 0.5 0.0 6 0.2 0.0 163 0.5 0.1
Total1 310 0.5 0.2 253 0.5 0.1 208 0.7 0.2 109 1.3 0.3 49 0.5 0.2 60 0.8 0.3 18 0.2 0.1 5 0.3 0.1 1,012 0.7 0.2
Notes:
1 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per River Segment.
2 Total number of measurements (n), and group mean (SD) for Focus Area and non-Focus Area mesohabitats per Geomorphic Reach.
3 Bankfull depth of Cleawater Plume indicates the mean bankfull depth of clear (non-turbid) water in the Clearwater Plume as referenced by the bankfull width of the mesohabitat in which it flows.
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10. FIGURES
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Figure 3-1. Aquatic habitat and mapping study area during 2013 field effort.
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Figure 4.1-1 Flows during mainstem Susitna River in 2011, 2012 and 2013 with the timing of 2013 field
surveys superimposed.
Aerial Photography
Aerial Videography
Tributary Ground Surveys
Mainstem Ground Surveys
Tributary Ground Surveys
2013
2011
2012
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Figure 4.1-2. Map of Upper River tributaries with tributaries selected for field-surveys identified.
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Figure 4.2-1 Map of Upper River basin lakes within the potential zone of reservoir inundation.
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Figure 4.4-1 Aerial video capture of the Lower Susitna River mainstem showing highly complex braided
channels characteristic of main channel habitats in this river section.
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APPENDIX A: REMOTE LINE MAPPING, 2012
[See separate file for Appendix.]
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APPENDIX B: UPPER SUSITNA RIVER SEGMENT REMOTE LINE
HABITAT MAPPING TECHNICAL MEMORANDUM
[See separate file for Appendix.]
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APPENDIX C: UPPER RIVER GROUND SURVEYS, 2013
[See separate file for Appendix.]
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APPENDIX D: MIDDLE RIVER GROUND SURVEYS, 2013
[See separate file for Appendix.]