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Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Study of fish passage barriers in the middle and upper Susitna River and
Susitna tributaries implementation plan
SuWa 1
Author(s) – Personal:
Author(s) – Corporate:
Prepared by HDR, Inc.
AEA-identified category, if specified:
Fisheries
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 1
Existing numbers on document:
Published by:
[Anchorage, Alaska : Alaska Energy Authority, 2013]
Date published:
May 15, 2013
Published for:
Prepared for Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Final or Draft status, as indicated:
Agency review draft
Document type:
Pagination:
viii, 25 p.
Related work(s):
Pages added/changed by ARLIS:
Notes:
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Study of Fish Passage Barriers in the Middle and
Upper Susitna River and Susitna Tributaries
Implementation Plan
Prepared for
Alaska Energy Authority
Prepared by
HDR, Inc.
May 15, 2013
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i May 2013
TABLE OF CONTENTS
1. Introduction ........................................................................................................................1
2. FERC Staff Recommendation ..........................................................................................1
3. Goals and Objectives .........................................................................................................2
4. Study Area ..........................................................................................................................2
5. Background and Existing Information ............................................................................2
6. Fish Passage Through Devils Canyon ..............................................................................2
7. Prepare a Detailed Plan .....................................................................................................4
7.1. Study Component Consultation .........................................................................4
7.1.1. Identify Fish Species to be Included in Passage Barrier Study ...... 4
7.1.2. Define Passage Criteria for Identified Fish Species ....................... 5
7.1.3. Select Number and Location of Study Sites for each Element of
Study Implementation ..................................................................... 6
7.1.4. File Results of Items (a), (b), and (c) .............................................. 7
7.1.5. Schedule Overview ......................................................................... 7
7.2. Effects of Load-following on Passage during Ice-cover Periods .......................7
7.3. Description of Study Sites and Modeling Methods ...........................................9
7.3.1. Proposed Study Sites for Modeling .............................................. 10
7.3.2. Modeling Methods for Ice-free Periods ........................................ 10
7.3.3. Modeling Methods for Ice-cover Periods ..................................... 11
7.4. Description of Ice-free Off-channel and Tributary Delta Study Sites .............13
7.5. Identification and Location of Existing Potential Fish Passage Barriers .........14
7.5.1. Middle and Upper River Above Devils Canyon ........................... 15
7.5.2. Middle River Below Devils Canyon ............ Error! Bookmark not
defined.
7.6. Study of Fish Passage Barriers in the Lower River .........................................16
7.7. Documentation of Consultation .......................................................................16
8. References Cited...............................................................................................................16
9. Tables ................................................................................................................................18
10. Figures ...............................................................................................................................20
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii May 2013
LIST OF TABLES
Table 1. Tally of off-channel and tributary deltas by Middle River Focus Area. ........................ 18
Table 2. Named and unnamed tributaries in the Middle River selected for fish passage barrier
investigation. ......................................................................................................................... 19
LIST OF FIGURES
Figure 1a. Three potential impediment areas (Impediments 1, 2, and 3) to fish passage on the
Susitna River located between Portage and Devil creeks at the top end of the Middle River
Segment (AEA 2013c). ......................................................................................................... 20
Figure 1b. Example of a location within Impediment area 1 where a velocity barrier could be
created at a high river discharge. Photo at PRM 154.8, September 11, 2012, 11,600cfs
(provisional) at Gold Creek................................................................................................... 21
Figure 2. Proposed HSC curve development priority (AEA 2013a). .......................................... 22
Figure 3. Example of proposed winter fish habitat use sampling sites at the Skull Creek
Complex in the Middle Susitna River Segment (AEA 2013e). ............................................ 23
Figure 4. Predicted stage hydrographs in the Susitna River at Gold Creek (USGS 15292000)
under Pre-Project and Maximum Load Following OS-1 conditions during the week of
January 8 to 14, 1984. Actual results may differ from those depicted as a result of ice
formation in the river (AEA 2013d). .................................................................................... 24
Figure 5. Conceptual layout of 2-D coarse and fine mesh modeling within the proposed
Whiskers Slough Focus Area. .............................................................................................. 25
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii May 2013
LIST OF ACRONYMS AND SCIENTIFIC LABELS
Abbreviation Definition
Active floodplain The flat valley floor constructed by a river during lateral channel migration and
deposition of sediment under current climate conditions.
ADF&G Alaska Department of Fish and Game
AEA Alaska Energy Authority
Age-0 juvenile
The description of an organism that, in its natal year, has developed the anatomical
and physical traits characteristically similar to the mature life stage, but without the
capability to reproduce.
Algae Single-celled organisms (as individual or cells grouped together in colonies) that
contain chlorophyll-a and are capable of the photosynthesis.
Anadromous Fishes that migrate as juveniles from freshwater to saltwater and then return as
adults to spawn in freshwater.
APA Alaska Power Authority
APA Project APA Susitna Hydroelectric Project
Backwater
Off-channel habitat characterization feature found along channel margins and
generally within the influence of the active main channel with no independent
source of inflow. Water is not clear.
Bank
The sloping land bordering a stream channel that forms the usual boundaries of a
channel. The bank has a steeper slope than the bottom of the channel and is
usually steeper than the land surrounding the channel.
Bankfull stage (flow) The discharge at which water completely fills a channel; the flow rate at which the
water surface is level with the floodplain.
Bankfull width The width of a river or stream channel between the highest banks on either side of
a stream.
Baseline
Baseline (or Environmental Baseline): the environmental conditions that are the
starting point for analyzing the impacts of a proposed licensing action (such as
approval of a license application) and any alternative.
Benthos (benthic) Defining a habitat or organism found on the streambed or pertaining to the
streambed (or bottom) of a water body.
Braided streams
Stream consisting of multiple small, shallow channels that divide and recombine
numerous times. Associated with glaciers, the braiding is caused by excess
sediment load.
Break-up Disintegration of ice cover.
Cascade
The steepest of riffle habitats. Unlike rapids, which have an even gradient,
cascades consist of a series of small steps of alternating small waterfalls and
shallow pools.
Catch per unit effort The quantity of fish caught (in number or in weight) with one standard unit of fishing
effort.
cfs cubic feet per second
Channel A natural or artificial watercourse that continuously or intermittently contains water,
with definite bed and banks that confine all but overbank stream flows.
Cross-section A plane across a river or stream channel perpendicular to the direction of water
flow.
Depth Water depth at the measuring point (station).
Devils Canyon
Located at approximately Susitna River Mile (RM) 150-161, Devils Canyon contains
four sets of turbulent rapids rated collectively as Class VI. This feature is a partial
fish barrier because of high water velocity.
Distribution (species) The manner in which a biological taxon is spatially arranged.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iv May 2013
Abbreviation Definition
et al. “et alia”; and the rest
FERC Federal Energy Regulatory Commission
Fishwheel
A device for catching fish which operates much as a water-powered mill wheel. A
wheel complete with baskets and paddles is attached to a floating dock. The wheel
rotates due to the current of the stream it is placed into. The baskets on the wheel
capture fish traveling upstream. The fish caught in the baskets fall into a holding
tank.
Flood Any flow that exceeds the bankfull capacity of a stream or channel and flows out on
the floodplain.
Floodplain
1. The area along waterways that is subject to periodic inundation by out-of-bank
flows. 2. The area adjoining a water body that becomes inundated during periods of
over-bank flooding and that is given rigorous legal definition in regulatory programs.
3. Land beyond a stream channel that forms the perimeter for the maximum
probability flood. 4. A relatively flat strip of land bordering a stream that is formed by
sediment deposition. 5. A deposit of alluvium that covers a valley flat from lateral
erosion of meandering streams and rivers.
Focus Area Areas selected for intensive investigation by multiple disciplines as part of the AEA
study program.
Fork length A measurement used frequently for fish length when the tail has a fork shape.
Projected straight distance between the tip of the snout and the fork of the tail.
Fry A recently hatched fish. Sometimes defined as a young juvenile salmonid with
absorbed egg sac, less than 60 mm in length.
Fyke net Hoop nets are tubular shaped nets with a series of hoops or rings spaced along the
length of the net to keep it open.
Geomorphic reach Level two tier of the habitat classification system. Separates major hydraulic
segments into unique reaches based on the channel’s geomorphic characteristic.
Geomorphology The scientific study of landforms and the processes that shape them.
Gillnet With this type of gear, the fish are gilled, entangled or enmeshed in the netting.
These nets may be used to fish on the surface, in midwater or on the bottom.
GIS
Geographic Information System. An integrated collection of computer software and
data used to view and manage information about geographic places, analyze
spatial relationships, and model spatial processes.
Glacier geometry changes Changes in the size or shape of a glacier over time.
Glide An area with generally uniform depth and flow with no surface turbulence. Low
gradient; 0-1 % slope.
GPS global positioning system. A system of radio-emitting and -receiving satellites used
for determining positions on the earth.
Groundwater (GW) In the broadest sense, all subsurface water; more commonly that part of the
subsurface water in the saturated zone.
Habitat
The environment in which the fish live, including everything that surrounds and
affects its life, e.g. water quality, bottom, vegetation, associated species (including
food supplies). The locality, site and particular type of local environ ment occupied
by an organism.
Hook and line A type of fishing gear consisting of a hook tied to a line.
Hoop net Hoop nets are tubular shaped nets with a series of hoops or rings spaced along the
length of the net to keep it open.
Ice cover A significant expanse of ice of any form on the surface of a body of water.
ILP Integrated Licensing Process
Inclined plane trap This trap consists of a revolving screen suspended between two pontoons.
Downstream migrant fish reaching the back of the trap are dropped into a live box
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page v May 2013
Abbreviation Definition
where they can later be enumerated.
Instream flow The rate of flow in a river or stream channel at any time of year.
Juvenile A young fish or animal that has not reached sexual maturity.
licensing participants; Participants Agencies, ANSCA corporations, Alaska Native entities and other licensing
participants
Life stage
An arbitrary age classification of an organism into categories relate to body
morphology and reproductive potential, such as spawning, egg incubation, larva or
fry, juvenile, and adult.
Lower segment Susitna The Susitna River from Cook Inlet (RM 0) to the confluence of the Chulitna River at
RM 98.
m meter(s)
m2 square meter(s)
Macroinvertebrate An invertebrate animal without a backbone that can be seen without magnification.
Main channel For habitat classification system: a single dominant main channel. Also, the primary
downstream segment of a river, as contrasted to its tributaries.
Main channel habitat
Level four tier of the habitat classification system. Separates main channel habitat
types including: tributary mouth, main channel, split main channel, multiple split
main channel and side channel into mesohabitat types. Mesohabitat types include
pool, glide, run, riffle, and rapid.
Mainstem
Mainstem refers to the primary river corridor, as contrasted to its tributaries.
Mainstem habitats include the main channel, split main channels, side channels,
tributary mouths, and off-channel habitats.
Mainstem habitat
Level three tier of the habitat classification systems. Separates mainstem habitat
into main channel, off-channel, and tributary habitat types. Main channel habitat
types include: tributary mouth, main channel, split main channel, multiple split main
channel and side channel. Off-channel habitat types include: side slough, upland
slough, backwater, and beaver complex. Tributary habitat is not further categorized.
Major hydraulic segment
Level one tier of the habitat classification system. Separates the River into three
segments: Lower River (RM 0-98), Middle River (RM 98-184), and Upper River (RM
184-233).
Mesh size The size of holes in a fishing net.
Mesohabitat
A discrete area of stream exhibiting relatively similar characteristics of depth,
velocity, slope, substrate, and cover, and variances thereof (e.g., pools with
maximum depth <5 ft, high gradient rimes, side channel backwaters).
Middle segment Susitna The Susitna River from the confluence of the Chulitna River at RM 98 to the
proposed Watana Dam Site at RM 184.
Migrant (life history type) Some species exhibit a migratory life history type and undergo a migration to from
rivers/lakes/ocean.
Migration Systematic (as opposed to random) movement of individuals of a stock from one
place to another, often related to season.
Minnow trap Normally composed of small steel mesh with 2-piece torpedo shape design, this
trap is disconnected in the middle for easy baiting and fish removal.
N/A not applicable or not available
Non-native Not indigenous to or naturally occurring in a given area.
ºC degrees Celsius
ºF degrees Fahrenheit
Off-channel Those bodies of water adjacent to the main channel that have surface water
connections to the main river at some discharge levels.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vi May 2013
Abbreviation Definition
Off-channel habitat Habitat within those bodies of water adjacent to the main channel that have surface
water connections to the main river at some discharge levels.
Out-migrant trap Several types of trapping equipment that can be used to estimate the abundance of
downstream migrating anadromous salmonid smelts.
Overwintering
Freshwater habitat used by salmonids during the winter for incubation of eggs and
eleven in the gravel and for rearing of juveniles overwintering in the stream system
before migrating to saltwater the following spring.
pH A measure of the acidity or basicity of a solution.
PIT Passive Integrated Transponder tags used to individually identify animals and
monitor their movements.
PM&E protection, mitigation and enhancement
Pool Slow water habitat with minimal turbulence and deeper due to a strong hydraulic
control.
POW Palustrian open water (ponds under 20 ac)
PRM
Project River Mile(s) based on the digitized wetted width centerline of the main
channel from 2012 Matanuska-Susitna Borough digital orthophotos. PRM 0.0 is
established as mean lower low water of the Susitna River confluence at Cook Inlet.
Project Susitna-Watana Hydroelectric Project
Radiotelemetry Involves the capture and placement of radio-tags in adult fish that allow for the
remote tracking of movements of individual fish.
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% slope.
Rearing Rearing is the term used by fish biologists that considers the period of time in which
juvenile fish feed and grow.
Resident Resident fish as opposed to anadromous remain in the freshwater environment
year-round
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% slope.
Riparian Pertaining to anything connected with or adjacent to the bank of a stream or other
body of water.
River A large stream that serves as the natural drainage channel for a relatively large
catchment or drainage basin.
River corridor
A perennial, intermittent, or ephemeral stream and adjacent vegetative fringe. The
corridor is the area occupied during high water and the land immediately adjacent,
including riparian vegetation that shades the stream, provides input of organic
debris, and protects banks from excessive erosion.
River mile The distance of a point on a river measured in miles from the river's mouth along
the low-water channel.
RM River Mile(s) referencing those of the APA Project.
RSP Revised Study Plan
Run (habitat)
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. Velocities are on border of fast and slow water. Gradients are approximately
0.5 % to less than 2%. Generally deeper than riffles with few major flow
obstructions and low habitat complexity.
Run (migration) Seasonal migration undertaken by fish, usually as part of their life history; for
example, spawning run of salmon, upstream migration of shad. Fishers may refer to
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vii May 2013
Abbreviation Definition
increased catches as a “run” of fish, a usage often independent of their migratory
behavior.
Screw trap A floating trap that relies on an Archimedes screw built into a screen covered cone
that is suspended between two pontoons is used.
Seine (beach)
A fishing net that hangs vertically in the water with its bottom edge held down by
weights and its top edge buoyed by floats. Seine nets can be deployed from the
shore as a beach seine, or from a boat.
Side channel
Lateral channel with an axis of flow roughly parallel to the mainstem, which is fed by
water from the mainstem; a braid of a river with flow appreciably lower than the
main channel. Side channel habitat may exist either in well-defined secondary
(overflow) channels, or in poorly-defined watercourses flowing through partially
submerged gravel bars and islands along the margins of the main stem.
Side slough Off-channel habitat characterization of an Overflow channel contained in the
floodplain, but disconnected from the main channel. Has clear water,
Slope The inclination or gradient from the horizontal of a line or surface.
Slough
A widely used term for wetland environment in a channel or series of shallow lakes
where water is stagnant or may flow slowly on a seasonal basis. Also known as a
stream distributary or anabranch.
Smolt An adolescent salmon which has metamorphosed and which is found on its way
downstream toward the sea.
Smoltification The physiological changes anadromous salmonids and trout undergo in freshwater
while migrating toward saltwater that allow them to live in the ocean.
Spawning The depositing and fertilizing of eggs by fish and other aquatic life.
Split main channel Main channel habitat characterization where three of fewer distributed dominant
channels.
Stratified sampling
A method of sampling from a population. In statistical surveys, when
subpopulations within an overall population vary, it is advantageous to sample each
subpopulation (stratum) independently. Stratification is the process of dividing
members of the population into homogeneous subgroups before sampling.
Three Rivers Confluence
The confluence of the Susitna, Chulitna, and Talkeetna rivers at Susitna River Mile
(RM) 98.5 represents the downstream end of the Middle River and the upstream
end of the Upper River.
Tributary A stream feeding, joining, or flowing into a larger stream (at any point along its
course or into a lake). Synonyms: feeder stream, side stream.
Turbidity The condition resulting from the presence of suspended particles in the water
column which attenuate or reduce light penetration.
TWG Technical Workgroup
Upland slough
Off-channel habitat characterization feature that is similar to a side slough, but
contains a vegetated bar at the head that is rarely overtopped by mainstem
flow. Has clear water.
Upper segment Susitna The Susitna River upstream of the proposed Watana Dam Site at RM 184.
Watana Dam
The dam proposed by the Susitna-Watana Hydroelectric project. The approximately
750-foot-high Watana Dam (as measured from sound bedrock) would be located at
river mile (RM) 184 on the Susitna River. The dam would block the upstream
passage of Chinook salmon, possibly other salmon species, and resident fish that
migrate through and otherwise use the proposed Watana Dam site and upstream
habitat in the Susitna River and tributaries.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page viii May 2013
STUDY PLANS REFERRED TO IN THIS IMPLEMENTATION PLAN
RSP Section Study Section
Geomorphology (RSP Section 6) Fluvial Geomorphology Modeling below Watana Dam Study (Section 6.6)
Hydrology-Related Resources (RSP
Section 7)
Groundwater Study (Study Section 7.5)
Ice Processes in the Susitna River Study (Study Section 7.6)
Instream Flow (RSP Section 8) Fish and Aquatics Instream Flow Study (Study Section 8.5)
Fish and Aquatic Resources (RSP
Section 9)
Study of Fish Distribution and Abundance in the Upper Susitna River (Study
Section 9.5)
Study of Fish Distribution and Abundance in the Middle and Lower Susitna River
(Study Section 9.6)
Salmon Escapement Study (Study Section 9.7)
Study of Fish Passage Feasibility at Watana Dam (Study Section 9.11)
Study of Fish Passage Barriers in the Middle and Upper Susitna River and Susitna
Tributaries (Study Section 9.12)
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 1 May 2013
1. INTRODUCTION
On December 14, 2012, Alaska Energy Authority (AEA) filed with the Federal Energy
Regulatory Commission (FERC) its Revised Study Plan (RSP), which included 58 individual
study plans (AEA 2012). Included within the RSP was the Study of Fish Passage Barriers in the
Middle and Upper Susitna River and Susitna Tributaries, Section 9.12. RSP Section 9.12
focuses on the methods for locating, describing, and assessing potential fish passage barriers in
the Middle and Upper Susitna River that could be created or eliminated as a result of Project
construction and operation. RSP 9.12 provided goals, objectives, and proposed methods for
identification, classification, measurement, and analysis of potential fish passage barriers.
On February 1, 2013, FERC staff issued its study determination (SPD) for 44 of the 58 studies,
approving 31 studies as filed and 13 with modifications. RSP Section 9.12 was one of the 13
approved with modifications.
In accordance with FERC’s study plan determination, recommended modifications are addressed
in detail in this implementation plan. Any area not discussed within this implementation plan
will remain as detailed in the RSP.
2. FERC STAFF RECOMMENDATION
In its February 01, 2013 SPD FERC recommended the following.
We recommend that AEA assess discharge conditions at the streamflow gages established by
AEA closest to Devils Canyon and near the dam site during the time periods when salmon
are documented to successfully pass upstream of the Devils Canyon passage impediment in
2013 and 2014 (via radio-tagging as set forth in study 9.7, salmon escapement), and
document the results in the initial and updated study reports.
We do not recommend use of any of AEA’s criteria set forth in section 9.12.4.4 of the RSP for
excluding study sites from the Middle River passage barrier evaluation. Instead, we
recommend that AEA prepare and file a detailed plan by no later than June 15, 2013, that
provides the additional information described below on implementation of the study within
the Middle River study area.
1) A specific schedule for completing the following Middle River study components
proposed for future development in consultation with the TWG as set forth in section
9.12.4 of the RSP: (a) identifying fish species to be included in the passage barrier study;
(b) defining the passage criteria for the identified fish species; (c) selecting the number
and location of study sites for each element of study implementation; and (d) filing the
results of items (a), (b), and (c).
2) A description of how the effects of load-following during the winter ice-cover period on
salmonid juvenile and fry passage (e.g., depth, velocity, potential ice blockages) from
mainstem into off-channel habitats would be evaluated.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 2 May 2013
3) A description of the specific methods as set forth in section 9.12.4.5 (e.g., 2-dimensional
modeling, or other unspecified modeling approach) that would be applied at the off-
channel and tributary delta locations selected for the depth barrier analysis. This would
include an explanation of the proposed methods and study sites for the open-water period
for adult and juvenile fish, and the ice-cover period for juvenile fish.
4) A description of a subsample of tributary deltas and off-channel habitat entrances within
Middle River focus areas where velocity measurements will be taken to determine if
velocity barriers to juvenile salmonids (particularly salmonid fry) would be created at
tributary deltas and off-channel habitat entrances by modifications to river stage and
discharge through proposed project operations.
5) Documentation that a draft plan and schedule were provided to FWS, NMFS, and any
other TWG participants at least 30 days prior to the due date of the plan and schedule
(allowing at least 15 days for comment); a description of how FWS’, NMFS’, or other
TWG participant’s comments are incorporated into the final plan; and an explanation for
why any of FWS’, NMFS’, or other TWG participant’s comments are not incorporated
into the final plan.
3. GOALS AND OBJECTIVES
Study goals and objectives of this implementation plan are the same as those described in RSP
9.12.
4. STUDY AREA
The study area for this implementation plan is the same as described in RSP 9.12.
5. BACKGROUND AND EXISTING INFORMATION
The background and existing information for this implementation plan is the same as described
in RSP 9.12.
6. FISH PASSAGE THROUGH DEVILS CANYON
The February 1, 2013 Study Plan Determination states:
We recommend that AEA assess discharge conditions at the streamflow gages established by
AEA closest to Devils Canyon and near the dam site during the time periods when salmon
are documented to successfully pass upstream of the Devils Canyon passage impediment in
2013 and 2014 (via radio-tagging as set forth in study 9.7, salmon escapement), and
document the results in the initial and updated study reports.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 3 May 2013
As recommended by FERC (2013a), AEA will rely primarily on data collection and analysis
under RSP Section 9.7 – Salmon Escapement Study to assess potential effects of the Project on
passage of adult salmon through Devils Canyon.
Devils Canyon is a narrow rock-walled canyon extending from approximately PRM 154 to PRM
165. Within this 11 mile distance, three locations (sections of river) were identified where
investigators suspected that at least partial impediments to adult salmon passage likely occur (as
based on observations of holding behavior and some fish not continuing further upstream), and
probably depending on flow level. These three locations are numbered in an upstream direction
as potential impediments 1, 2, and 3. Within these general areas there are sections for which it is
speculated that velocities could exceed the swimming capabilities of adult salmon. Figure1a
shows the general locations of these suspected impediments. Figure 1b is an example of a
location within Impediment 1 where a velocity blockage could be created at a high river
discharge.
Results from AEA’s 2012 studies on salmon passage through Devils Canyon are reported in
Adult Salmon Distribution and Habitat Utilization Study (AEA 2013b). Chinook salmon was the
only species identified migrating upstream of any of the three suspected impediments in Devils
Canyon (PRM 154–165). One tagged sockeye salmon and one tagged chum salmon approached
the farthest downstream impediment (Impediment 1) but did not migrate above it. Of the 313
radio tagged Chinook salmon that were tagged at Curry and moved above the “Gateway” station
at PRM 140, 23 (7 percent) migrated above Impediment 1, 20 (6 percent) above Impediment 2,
and 10 (3 percent) above Impediment 3. Four (1 percent) of these Chinook salmon had final
destinations upstream of the Project dam site. Of the Chinook salmon tagged in the Lower River
and that subsequently migrated upstream past the Lane Creek station (PRM 117), three migrated
above Impediment 1; of these, two migrated above Impediment 3. All radio-tagged fish that
approached Impediment 2 successfully passed above it.
In 2012, of all 26 tagged Chinook salmon (Lower and Middle River tagging-sites combined) that
migrated upstream of Impediment 1, seven eventually migrated back downstream of Devils
Canyon and were assigned to Portage Creek as a final destination. From the 12 tagged Chinook
salmon (Lower and Middle River tagging-sites combined) that migrated upstream of Impediment
3, five eventually migrated back downstream of Devils Canyon and were assigned to Portage (4)
or Chinook Creek (1) as a final destination. Chinook salmon migrated through the Devils
Canyon impediments from July 7 to July 20. Average daily discharge of the Susitna River at
Gold Creek (RM 136) ranged from 17,300–31,100 cubic feet per second (cfs) when Chinook
salmon passed Impediment 1, 17,300–21,300 cfs when fish passed Impediment 2, and 17,300–
19,000 cfs when fish passed Impediment 3.
RSP 9.7- Salmon Escapement Study radio tracking elements will be expanded in 2013. The
number of tags applied in the Lower River will be increased from approximately 450 to 700
Chinook salmon. Additional tags will increase the potential for more tagged Chinook salmon to
pass through Devils Canyon when compared to 2012. In the Middle River, 2013 efforts will
attempt to shift some of the Chinook salmon tagging at Curry (PRM 123.6) to an area at the
entrance of Devils Canyon (~PRM 164.8); this has the potential to double the number of tagged
fish in the Canyon compared to 2012. Fixed-station telemetry sites in 2013 will have the same
number of locations (3) within Devils Canyon as in 2012 and will have similar level of aerial
surveying. However, 2013 efforts will have new fixed stations on the Susitna River at Fog
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Creek, Watana Dam site, and Watana Creek to document the movement of tagged fish that have
passed Devils Canyon and continue their migration upstream.
Mean daily discharge records during the time of attempted passage by radio-tagged salmon will
be obtained from both the USGS Gold Creek stream gage and one or more of the AEA stream
gages located in the Devils Canyon Area (ESS55 or ESS60). The gage closest to the impediment
will be used or discharge will be prorated between the two gages to obtain the most accurate
discharge estimate at the impediment at the time of attempted passage. Discharges during both
successful and unsuccessful passage by radio-tagged fish will be compared to modeled post-
Project discharges during the period when adult salmon would be attempting to pass through
Devils Canyon.
Studies described above will contribute substantially to the understanding and evaluation of
potential Project effects on salmon passage through Devils Canyon.
All field data collection will be conducted as part of RSP Section 9.7 and RSP Section 8.5 -
Hydraulic Routing and Operations Modeling.
7. PREPARE A DETAILED PLAN
The February 1, 2013 Study Plan Determination states:
We do not recommend use of any of AEA’s criteria set forth in section 9.12.4.4 of the RSP for
excluding study sites from the Middle River passage barrier evaluation. Instead, we
recommend that AEA prepare and file a detailed plan by no later than June 15, 2013, that
provides the additional information described below on implementation of the study within
the Middle River study area.
AEA is fulfilling this recommendation by providing this implementation plan.
7.1. Study Component Consultation
The February 1, 2013 Study Plan Determination states:
A specific schedule for completing the following Middle River study components proposed
for future development in consultation with the TWG as set forth in section 9.12.4 of the RSP:
(a) identifying fish species to be included in the passage barrier study; (b) defining the
passage criteria for the identified fish species; (c) selecting the number and location of study
sites for each element of study implementation; and (d) filing the results of items (a), (b), and
(c).
The requested elements are addressed below in the order presented.
7.1.1. (a) Identify Fish Species to be Included in Passage Barrier Study
Given the interdependencies between the barriers assessment and ISF physical habitat data
collection, AEA proposes that target species for the fish barrier studies be the same as, or a sub-
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set of, those selected for Instream Flow Habitat Modeling (RSP 8.5). For planning purposes,
target species proposed in RSP 8.5 were assumed to include Chinook, coho, chum, and sockeye
salmon, rainbow trout, arctic grayling, Dolly Varden, burbot, longnose sucker, humpback
whitefish, and round whitefish. These target species were selected because of they are generally
considered the most sensitive to habitat loss through manipulation of flows in the Susitna River.
All of theses species also have been identified as target species for RSP Section 9.11 - Study of
Fish Passage Feasibility at Watana Dam. RSP 9.11 target species selection was first based on
presence of the species in the Upper River, secondly on the following three criteria, and thirdly
in consultation with the Fish Passage Technical Team at their workshop on April 9 and 10, 2013.
Aspects of these criteria used by the Fish Passage study team are also useful for selecting target
species for passage barrier studies.
The species exhibits migratory behavior – Fish passage has a greater importance to
species that may exhibit migratory behavior as part of their natural life history compared
to fish that exhibit only localized movement, especially when the migration is necessary
to complete the life cycle of the species.
The species has high relative abundance – Species that are relatively abundant in the
Upper River and its tributaries would theoretically utilize fish passage facilities with
greater frequency than less abundant species, disregarding other criteria (e.g., migratory
behavior).
The species is important to commercial, sport, or subsistence fisheries – Species that are
harvested in commercial, sport, or subsistence fisheries have added importance with
regard to the study of fish passage feasibility.
Since submittal of RSP 8.5, AEA and the Technical Workgroup (TWG) have engaged in
meetings to initiate discussions of target species for HSC development and inclusion in instream
flow habitat modeling. At the March 27 TWG meeting (AEA 2013a), AEA presented a
proposed species priority list for HSC development (Figure 2). In subsequent meetings during
2013, the Instream Flow Technical Team will meet to finalize target species and life stage for
which HSC will be developed. AEA proposes that selection of target species for fish passage
analysis occur toward the end of the HSC development process. Technical Team members,
licensing participants, and AEA will have gained substantial knowledge of species and lifestage
utilization of off-channel habitats, seasonal movement into and out of off-channel habitats, and
microhabitat (depth and velocity) selection. This information will be informative to the
refinement of target species selection and passage criteria.
7.1.2. (b) Define Passage Criteria for Identified Fish Species
Basic categories of fish passage criteria include water depth, water velocity, and fish leaping
ability. The majority of passage criteria are based on the demonstrated swimming ability of a
species/lifestage in a laboratory, or in some cases, under controlled natural conditions.
The onus for most research on adult swimming ability is related to upstream fish passage at
manmade structures such as fishways, low head dams, weirs, and culverts. Most information on
juvenile and fry swimming ability is related to entrainment (open diversions) and impingement
(fish screens), of downstream migrating salmonids. Swim speed is the primary criterion
developed from these studies. Although information exists, depth criterion for fry and juvenile
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salmonids is less researched. Although criteria are available for some of the proposed non-
salmonids target species, swimming capabilities for non-salmonids is the least researched.
AEA is in the process of collating existing information on passage criteria for the fish Passage
Feasibility Study. Draft appendices summarizing these data have been developed for most of the
target species listed above and data will be summarized for the remaining species in Q2 of 2013.
These materials are being developed in collaboration with the Fish Passage Technical Team.
AEA proposes to use this information to inform passage criteria for the barrier study. Any
additional information necessary for the barriers assessment will be collated and summarized in
Q3 and Q4 of 2013. AEA proposes that consultation with Licensing Participants regarding
refinement of fish passage criteria occurs during TWG Habitat Suitability Criteria development
meetings scheduled for late 2013. This timing would benefit passage criteria discussions
because of the knowledge gained from the HSC development process regarding species/lifestage
use of different off-channel habitat types and from HSC field observations.
7.1.3. (c) Select Number and Location of Study Sites for each Element of
Study Implementation
Study elements and respective schedules for study site selection are presented below. Detailed
descriptions of these study elements and study sites are provided in this implementation plan.
Study Element Schedule for Study Site Selection
Adult salmon passage in Upper River
tributaries
Seventy nine tributaries (study sites) were
selected and surveyed for Chinook salmon
barriers in 2012 (AEA 2013b). Follow-up
surveys at a sub-set of these tributaries are
schedule for July 2014.
No additional tributaries for fish passage barrier
studies in the Upper River are proposed.
Adult salmon passage through Devils
Canyon
Impediment locations and radio-tracking
stations were established in 2012 for studies of
salmon passage at Devils Canyon (AEA
2013c).
No additional tracking stations within the
Devils Canyon area are proposed.
Intensive study of passage at off-channel and
tributary deltas for adult and juvenile/fry
lifestages in Middle River Focus Areas
during ice-free and ice-cover periods.
The number and location of all Focus Areas,
within which all intensive study of fish passage
will occur, will be determined as part of the
implementation of RSP Section 8.5 - Fish and
Aquatics Instream Flow Study and filed with
FERC by May 31, 2013.
Identification and Location of physical In 2013, AEA proposes to ground survey 10
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barriers to fish passage in tributaries outside
of Middle River Focus Areas.
tributaries for physical barriers within the zone
of hydrologic influence (ZHI1) in the Middle
River below Devils Canyon. These tributaries
are listed below in Section 7.5.2.
7.1.4. (d) File Results of Items (a), (b), and (c)
The results of these implementation ideas will be included within the RSP Section 9.12 study
reports filed with the Commission.
7.1.5. Schedule Overview
Requirement Process
Proposed
Schedule for
Consultation
Define Fish Species Define as part of instream flow target species selection Q1-Q2, 2013
Define Criteria Define immediately following instream flow HSC development Q1-Q2, 2014
Select Number and
Location of Fish
Passage Study Sites
Locations of all study sites are proposed in this detailed implementation
plan.
To be determined
in final
Implementation
Plan
7.2. Effects of Load-following on Passage during Ice-cover Periods
A description of how the effects of load-following during the winter ice-cover period on
salmonid juvenile and fry passage (e.g., depth, velocity, potential ice blockages) from
mainstem into off-channel habitats would be evaluated.
RSP 9.12 will rely on data collected by the intensive, multidisciplinary studies in Focus Areas to
evaluate the effects of load-following on juvenile and fry passage at off-channel habitats during
the ice cover period. These studies include:
RSP 7.6 - Ice Processes in the Susitna River Study
RSP 7.5 - Groundwater Study
RSP 8.5 - Fish and Aquatics Instream Flow Study
Hydraulic Routing and Operations Modeling;
Winter Habitat Use Sampling;
Periodicity;
Habitat-Specific Model Development
1 The ZHI (zone of hydrologic influence) is defined as the approximated section of tributary extending from the Susitna River’s
modeled water’s edge at a 1.5 year flow return interval downstream to the tributary’s confluence with the Susitna River at a base
flow.
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RSP 9.6 - Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River
An example of co-location of winter studies in Focus Areas is illustrated in Figure 3.
To study the effects of load-following on fish passage in the Middle River, AEA will use the
River1D predictive ice, hydrodynamic, and thermal model to simulate time-variable flow
routing, heat-flux processes, seasonal water temperature variation, frazil ice development, ice
transport processes, and ice-cover growth and decay.
The River1D model will be used to simulate conditions in the Middle River due to various
project operating scenarios and predict changes in water temperature, frazil ice production, ice
cover formation, elevation and extent of ice cover, and flow hydrograph. The model will also be
used to predict ice cover stability, including potential for jamming, under load-following
fluctuations. For the spring melt period, the model will be used to predict ice-cover decay,
including the potential for break-up jams. Proposed operating scenarios will include, at a
minimum, the load-following scenario described in the Pre-Application Document (PAD) and a
base-load scenario.
For Focus Areas, AEA will model and characterize ice processes using either River1D or
River2D models. The appropriate model will be selected on the basis of which model better
simulates the characteristics at the particular study location. The objective of this modeling will
be to evaluate project effects on smaller scale habitat in the focus areas to provide physical data
on winter habitat for Study 8.5 (fish and aquatics instream flow) and Study 9.12 (fish passage
barriers).
As discussed by FERC (2013a), accuracy of hydrodynamic modeling during the ice-cover
periods may or may not be sufficient to predict passage conditions at the small, local scale.
FERC states:
…it’s not clear if the winter model can accurately predict stage-discharge relationships and
streamflow velocities at a scale that is fine enough to evaluate the effects of daily flow
fluctuations during proposed winter load-following operations on fish passage conditions
from the mainstem into off-channel habitats…While AEA’s proposed fish passage barrier
study plan does not appear to specifically address this issue, we assume the intensive,
multidisciplinary study elements that would be implemented within the focus areas would
provide some information to evaluate fish passage conditions between the mainstem and off-
channel habitats under ice cover and load-following operations.
The following is a discussion of multidisciplinary methods proposed by AEA to address FERC’s
comment.
The hydraulic data to be derived from the Focus Area ice models will be determined on a case-
by-case basis by the needs of instream flow, geomorphology, fish passage, and other studies, but
will include at a minimum: extent of inundation; flow stages; and, velocities for post-Project
winter conditions under load-following and base-load scenarios.
Initial modeling results of load-following effects on stage indicate that in an ice-free channel
Project load-following (maximum load following OS-1 scenario) in January would result in a
daily stage cycle (fall and rise) of 1.0 to 1.5 feet at the Susitna stream gage near Gold Creek
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(AEA 2013d). These initial modeling results also indicate that during the winter months, the
average stage during ice-free periods, in the vicinity of Gold Creek, will be approximately 3.5
feet higher with the Project than under existing ice-free periods. Figure 4 illustrates these initial
results.
The rise in stage described above is applicable to the ice-free period. Effects of load-following
on river stage during ice-cover periods will likely be much different than under ice-free periods.
One key finding of the 1980s modeling effort (Watana Dam only scenario) was that winter water
surface elevations under ice would generally be 2–7 feet higher under project conditions (RSP
7.6). The combination of a predicted rise in stage due to winter Project flow releases and a
predicted rise in stage due to ice-cover would be a 5-10 feet.
Obvious from these initial studies, but important to note is the dramatic difference in scale
between predicted increases in river stage (depth) of several feet under Project operations, and
the minimum depth criteria for juvenile and fry salmonid passage of 2 - 3 inches. At least for
depth predictions, initial results indicate that model error can be large and still have sufficient
accuracy to predict that depth would exceed 3 inches.
As highlighted by FERC above and discussed in more detail in Section 7.3.1 below, ice-process
modeling may not provide detailed and accurate information at the micro scale. The study does,
however, exhaust scientific methodologies and resources to provide data within the current
bounds of research. Further, in combination with other multidisciplinary studies in Focus Areas,
the models will be useful for predicting and evaluating effects of ice process on fish passage at
the macro scale.
As discussed by FERC (2013a), for the purposes of the passage studies, stage and velocity model
predictions for post-Project winter conditions under load-following and base-load scenarios will
be augmented with other winter-period multidisciplinary study elements.
AEA does not propose any field data collection in RSP 9.12 for this study element. All field data
collection will be conducted as proposed in other RSP’s, as described above.
7.3. Description of Study Sites and Modeling Methods
A description of the specific methods as set forth in section 9.12.4.5 (e.g., 2-dimensional
modeling, or other unspecified modeling approach) that would be applied at the off-channel
and tributary delta locations selected for the depth barrier analysis. This would include an
explanation of the proposed methods and study sites for the open-water period for adult and
juvenile fish, and the ice-cover period for juvenile fish.
Several environmental variables may affect adult and juvenile fish passage in sloughs, side
channels, and tributary deltas. Although some variables are the same, there are additional
variables during ice-cover periods not present during ice-free periods. In general, at a given
passage reach the water conditions (depth and velocity) interact with conditions of the channel
(length and uniformity and substrate size) to characterize the passage conditions that a particular
fish encounters when attempting to migrate into, within, and out of a slough, side channel, or
tributary delta. The likelihood of a particular fish successfully navigating through a difficult
passage reach will depend on these environmental conditions as well as the individual
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capabilities and condition of the fish. These fish passage variables will be studied in Focus
Areas using 1D and 2D models.
7.3.1. Proposed Study Sites for Modeling
As recommended by FERC (2013a), AEA will locate fish passage barrier intensive sampling
sites for both the ice-free and ice-cover periods within the selected Focus Areas. Ice-free data
collection includes a larger number and diversity of sample locations at off-channel and tributary
deltas. Ice-cover sample sites within Focus Areas will be fewer in number. Fewer ice-cover
sample sites are planned because of the inherent difficulties of measuring and modeling ice
process and associated hydrodynamic conditions that control fish passage.
With input from the RSP 9.12 study lead, Focus Area study sites for modeling juvenile passage
during the ice-cover period will be selected as part of RSP 7.6 - Ice Processes in the Susitna
River Study and RSP 8.5 - Fish and Aquatics Instream Flow Study. One objective of the Ice
Processes study is to develop detailed models and characterizations of ice processes at instream
flow Focus Areas in order to provide physical data on winter habitat for the instream flow study.
This study objective directly supports study site and modeling needs for juvenile fish passage
during ice-cover periods. In its April 1, 2013 study plan determination (FERC 2013b) FERC
concluded that:
AEA’s proposed focus area selection for the purposes of the ice processes study is consistent
with accepted methods (section 5.9(b)(6)), and should provide information necessary to
support the design of the project, assess environmental effects, and evaluate proposed
environmental measures (section 5.9(b)(5)). If the agencies conclude that the initial study
results or any other available study results suggest that it is still necessary to include
additional ice-specific focus areas, they could be requested in 2014 or in subsequent study
years after a showing of good cause as specified in sections 5.15(d) and 5.15(e) of the
Commission’s regulations.
Selection of proposed study sites for modeling adult and juvenile fish passage during the ice-free
period is described in Section 7.4, below.
7.3.2. Modeling Methods for Ice-free Periods
Depth and velocity passage for adults and juveniles in sloughs, upland sloughs, side channels,
and at tributary delta mouths in Focus Areas will be assessed following concepts similar to
ADF&G (1984b) in which depth, velocity, substrate, and length of the passage reach were
considered together to determine successful or unsuccessful passage into and within these
habitats. Data collection and modeling methods, including two-dimensional modeling, not
available in the 1980s, will be applied in the current studies.
As discussed by FERC (2013a), for fish passage during ice-free periods, AEA will rely on 2D
modeling already being conducted in Focus Areas under Section 6.6 - Fluvial Geomorphology
Modeling below Watana Dam Study and 8.5 - Fish and Aquatics Instream Flow Study. The
specific 2D models will be selected from a list of candidate models in coordination with other
studies and the licensing participants. As specified by FERC (2013b), AEA’s schedule for
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selecting the 2D model will be described in a technical memorandum prepared in the second
quarter of 2013. The 2-D model selected will be applied over the full extent of all Focus Areas.
As described in RSP 8.5, the 2-D model will utilize a variable mesh (also referred to as flexible
mesh). A variable mesh allows a finer mesh to be used in areas where either the information
desired or the condition being modeled requires higher spatial resolution (RSP 6.6.4). For off-
channels and tributary deltas, velocities, bathymetry, and substrate will be modeled at a fine
mesh grid size of 2m x 2m. Figure 5 is an example of fine mesh 2D modeling at off-channel
passage sites and coarse mesh modeling in the open water areas.
As in the ADF&G 1980s studies, passage in off-channel reaches requires evaluation under three
types of hydraulic conditions: breaching, backwater, and local discharge. The two-dimensional
model, coupled with the flow routing model and the groundwater model will be used to evaluate
passage conditions over the full range of pre- and post-Project flow conditions. To the extent
possible, passage criteria will be input to the 2D habitat model, yielding an integrated analysis
tool.
7.3.3. Modeling Methods for Ice-cover Periods
As described above in Section 7.2, ice-cover passage barrier modeling will rely on the river ice-
process model developed as part of RSP 7.6 - Ice Processes in the Susitna River Study. The river
ice-process model will rely on the River 1D hydrodynamic flow routing/thermal model to
determine large-scale changes to ice-cover timing and structure, and under-ice discharges
including stage fluctuations.
Ice-process studies will include 2D modeling at the Focus Area below Devils Canyon (where
there will likely be an ice-cover post-project to model), 1D modeling at Focus Areas upstream of
Devils Canyon for existing conditions, and using the open-water results for proposed conditions.
One objective of the ice processes study is to develop detailed models and characterizations of
ice processes at instream flow Focus Areas in order to provide more detailed physical data on
winter habitat for the instream flow study. RSP 7.6 Ice Processes study objective directly
supports study site and modeling needs for juvenile fish passage during ice-cover periods. In its
study plan determination, FERC (2013b) concluded that:
AEA’s proposed modeling approach should provide the information necessary to describe
project effects with respect to ice processes to a degree which is consistent with generally
accepted practices in the scientific community (section 5.9(b)(6)) and, if effectively
implemented, is expected to be able to satisfy the study objectives.
If the initial results of the 2013 or 2014 study seasons (as documented in the initial study
report) indicate that the model does not adequately evaluate project effects, and it becomes
clear on the basis of the results that other procedures should be followed in order to meet the
study objectives, then alternative methods and/or procedures could be added in 2014 or in
subsequent study years (sections 5.15(d) and 5.15(e)).
In addition to the ice-process modeling, AEA will rely on multidisciplinary data collection in
Focus Areas to assess potential effects of the Project on salmonid juvenile and fry passage during
the ice-cover period. Other multidisciplinary studies include: RSP 6.6 - Fluvial Geomorphology
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Modeling below Watana Dam Study and RSP 7.5 - Groundwater Study. Subsections from RSP
8.5 - Fish and Aquatics Instream Flow Study include: Hydraulic Routing and Operations
Modeling, Winter Habitat Use Sampling, Periodicity, and Habitat-Specific Model Development.
The ice processes study in 2013/2014 is planning repeat aerial observations at each focus area,
about 10 transects will be measured for ice thickness, frazil thickness, and water depth, and time-
lapse photography will be taken of a small portion of the area, including open-leads. For all of
the Focus Areas, ice thickness and elevation will be measured and inlets to side channels and
sloughs will be observed to qualitatively document any throughflow. Throughflow discharges
will be taken but only at the major side channels. The feasibility and application of ground
penetrating radar (GPR) will be investigated to determine if it will provide sufficient resolution
to determine frazil ice accumulations. This would provide broader and more continuous measure
of bed-fast ice thickness and floating solid ice thickness, than relying on auger holes.
Factors that affect fish passage are much more difficult to physically measure and much more
difficult to model for ice-cover than for ice-free conditions. The controlling forces over depth,
velocity, and the presence of potential obstructions are much different in ice-cover versus ice-
free conditions. Ice formation, including surface ice, frazil ice, and anchor ice can all physically
obstruct access into and out of off-channel habitats. Ice formations can reroute water flow,
thereby dewatering an access passageway that would otherwise be present under ice-free
conditions. An example of this is the blockage of water flow to an inlet of a side slough or side
channel, such that slough outflow is then insufficient for fish to access the off-channel habitat.
Localized passage conditions, such as a shllow riffle at the entrance of a slough, are extremely
dynamic and are virtually unpredictable during ice-cover periods. The presence of frazil and
structure ice appears or disappears in a matter of hours or days; likely opening up or closing fish
passageways at the same frequency. Passage opportunities might be improved at some locations
during winter Project operation due to the projected increase in river stage while at other
locations increase in stage might contribute to the degradation of passage conditions (ice
thickening at the inlets and outlets of off-channels).
These difficulties and uncertainties are noted here to bring attention to the difference in scale
between evaluations of fish passage in ice-cover versus ice-free conditions. Passage conditions
during ice-free periods can be observed and measured directly and modeled to the micro scale
(tenths of feet and velocity). Whereas, passage conditions during ice-cover periods are generally
not visible, very difficult to measure (the areal extent of the sample site might be the diameter of
an ice auger bit), and are modelable at a lesser resolution.
While ice-process modeling and winter Focus Area studies may provide some information at the
micro scale, they will likely be more useful for predicting and evaluating potential structural,
spatial, and temporal changes to fish passage at the macro scale. Some macro scale evaluations
during the ice-cover period include:
Potential change in the timing of ice formation and breakup in relation to migration
periodicities of juvenile salmonids;
Potential change in the thickness and elevation of ice at the inlets and outlets of off-
channels and tributary deltas;
Potential for blockages created by unstable or thickened ice from frequent flow
fluctuations;
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Potential changes in the formation and longevity of ice-free leads at slough entrances;
Potential changes in the depth of ice cover into and within off-channel habitats; i.e.
changes in passageways beneath the ice; and
Potential changes in ice-process in sloughs due to changes in the dominant source of
through flow.
AEA sees this research approach as a viable application of current, reasonably feasible scientific
application to address the issue. AEA does not propose any hydrodynamic or ice modeling
under RSP 9.12 for this study element. All hydrodynamic or ice modeling will be conducted as
proposed in other RSP’s, as described above.
7.4. Description of Ice-free Off-channel and Tributary Delta Study
Sites
A description of a subsample of tributary deltas and off-channel habitat entrances within
Middle River focus areas where velocity measurements will be taken to determine if velocity
barriers to juvenile salmonids (particularly salmonid fry) would be created at tributary
deltas and off-channel habitat entrances by modifications to river stage and discharge
through proposed project operations.
As recommended by FERC, AEA will locate fish passage study sites in Focus Areas. As
described in RSP 6.6, Section 6.6.1.2.4, the use of Focus Areas is to conduct concentrated
interdisciplinary studies at selected areas within the study area. Such areas represent specific
sections of the river that will be investigated across resource disciplines and will provide for an
overall understanding of interrelationships of river flow dynamics on the physical, chemical, and
biological factors that influence fish habitat. Focus Areas will involve portions of the Susitna
River and its floodplain where detailed study efforts will be jointly conducted by the Fish and
Aquatics Instream Flow (RSP 8.5), Riparian Instream Flow (RSP 8.6), Geomorphology (RSP
6.5), Ice Processes (RSP7.6), Groundwater (RSP 7.5), Characterization and Mapping of Aquatic
Habitats (Section 9.9) studies, and Fish Passage Barriers (RSP 9.12). The Focus Areas will allow
for a highly integrated, multidisciplinary effort to be conducted for evaluating potential Project
effects on key resource areas across a range of representative sites.
As required by FERC, final selection of ten Focus Areas will be completed by May 31, 2013
(2013b).
FERC (2013b) states:
We recommend that AEA: (1) consult with the TWG and select an appropriate focus area
within MR-2 to eliminate from the study; (2) consult with the TWG and establish an
additional focus area in geomorphic reach MR-7 that is sufficient for conducting
interdisciplinary studies, possibly near Lower McKenzie Creek or below Curry on old
Oxbow II; and (3) file a detailed description of the changes to the proposed focus area
locations in MR-2 and MR-7 by May 31, 2013, and include in the filing documentation of
consultation with NMFS, FWS, and Alaska DFG, including how the agency comments were
addressed.
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The ten Focus Areas under consideration include a large number and diversity of side channels,
side sloughs, upland sloughs, and tributary deltas that in sum would be representative of passage
conditions at off-channel and tributary deltas in the Middle River. The ten Focus Areas being
considered include a total of 34 side channels, 8 side sloughs (one with a beaver pond), 13
upland sloughs (one with a beaver pond), 2 macrohabitat backwaters, and 10 tributary
mouths/deltas. The inlets to these off-channel habitats will be modeled using 2D or 1D hydraulic
models as described in Section 6.3, above. Table 1 is a tally of off-channel and tributary deltas
by Focus Area. The domain for 2D modeling for each off-channel will extend from the mouth up
to and including the inlet or head of each off-channel as illustrated in Figure 5. This domain will
cover the fish entrance to the off-channel and breaching zone of the off channel, as well as the
entire length of the channel. The 2D modeling domain for tributary deltas will include the entire
delta within the zone of hydrologic influence.
Final hydrodynamic model selection in Focus Areas will occur as part of RSP 6.6 and 8.5 study
plan determination and modification process.
FERC (2013b) states:
Both one-dimensional and two-dimensional modeling approaches are consistent with
accepted practices for implementing an instream flow study using PHABSIM (section
5.9(b)(6)). We note, however, that AEA does not identify in the RSP the specific locations
where one-dimensional versus two-dimensional modeling would be applied, except for noting
that two-dimensional modeling would be applied within some focus areas. NMFS is
concerned that there may be disagreements about the selection of the appropriate habitat-
specific models and the specific locations where one-dimensional and two-dimensional
modeling would be applied. In our analysis and recommendations for Study 6.6
(geomorphology modeling), we are recommending that AEA file by the end of the second
quarter of 2013, its proposed technical memorandum that summarizes the specific models
and locations where one-dimensional and two-dimensional modeling would be applied
pursuant to Study 8.5 and Study 6.6.
AEA does not propose any data collection or hydrodynamic modeling under RSP 9.12 for this
study element. All data collection and hydrodynamic modeling will be conducted as proposed in
other RSPs, as described above.
7.5. Identification and Location of Existing Physical Barriers to Fish
Passage
This study element is in accordance with the first two goals and objectives of RSP 9.12.
1. Locate and categorize all existing fish passage barriers (e.g., falls, cascade, beaver dam,
road or railroad crossings) located in selected tributaries in the Middle and Upper Susitna
River (Middle River tributaries to be determined during study refinement).
2. Identify and locate using GPS the type (permanent, temporary, seasonal, partial) and
characterize the physical nature of any existing fish barriers located within the Project’s
zone of hydrologic influence.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 15 May 2013
7.5.1. Middle and Upper River
Tributaries above Devils Canyon (inclusive and upstream of Cheechako Creek) were surveyed
by helicopter in 2012, followed by ground surveys of some barriers that could not be positively
classified as a barrier from the air. Methods and results of these surveys are reported in AEA
(2013b) 2012 Upper Susitna River Fish Distribution and Habitat Study, Fish Passage Barriers
Assessment.
Seventy-nine drainages were surveyed throughout the study area between Devils Canyon and
Oshetna River. A total of 43 potential fish passage barriers were identified from the helicopter
within 29 of the 79 drainages surveyed (more than one barrier was identified on some
tributaries). Of these 43 barriers, a total of 35 definitive passage barriers were identified within
24 tributaries, the majority of which had falls with a vertical height greater than 10 feet and that
could be visually estimated from the helicopter. Three of the 35 barriers were surveyed from the
ground with a range finder to determine vertical and horizontal distances from the crest to the
plunge pool and were confirmed as barriers to fish passage. An additional 8 features, within 7
tributaries, were identified as potential fish passage barriers having falls heights visually
estimated to be near 10 feet or other apparent elements of passage barriers such as multiple
chutes and/or cascades and warranted further investigation; however, their challenging locations
in canyons precluded safely landing the helicopter for ground surveys.
During the 2013 and 2014 study seasons, subject to obtaining access authorization and necessary
permits, AEA will attempt on-the-ground measurement of the 8 features that could not be
positively identified from the air in 2012. On-the-ground measurement will depend on
reasonably safe access. Accessible features will be measured using the methods as described in
Alaska Department of Natural Resources (ADNR 2007) and Powers and Orsborn (1984). The
geometry of the obstacle will be surveyed including measurements of barrier height, leap
distance, and depth of leaping pool at an estimated high and low flow. The barrier will be
photographed and its location fixed with GPS. If the obstacle is clearly not a barrier, its location
and basic dimensions will be noted with no further measurements.
Also, during the 2013 and 2014 study seasons, subject to obtaining access authorization and
necessary permits, AEA will determine the crest elevation of all barriers within the inundation
zone and will measure on-the-gound dimensions of barriers within the reservoir elevation varial
zone. On-the-ground measurements assume reasonably safe access.
AEA proposes to conduct foot surveys for physical barriers and intensive hydrodynamic
modeling studies for velocity and depth barriers within the zone of hydrologic influence at 20
named and unnamed tributaries in the Middle River below Devils Canyon (Table 2). This will
include intensive study of ten tributary deltas in Focus Areas as described above in sections 7.2,
7.3, and 7.4. In 2013, AEA proposes to conduct foot surveys for physical barriers within the ZHI
of the remaining 10 primary Middle River tributaries below Devils Canyon (Table 2). Foot
survey field methods will be those described in RSP 9.12, Section 9.12.4.4.4. In addition to
methods described in RSP Section 9.12.4.4.4, data collection on deltas of these 10 tributaries will
include: tributary thalweg length; thalweg depth and velocity profile (longitudinal), stream
gradient; dominant and subdominant substrate; and photographs from several angles of the delta
and tributary. Several of these tributaries will be gaged (Table 2).
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 16 May 2013
7.6. Study of Fish Passage Barriers in the Lower River
Investigation and evaluation of fish passage barriers in the Lower River will follow a phased
approach in which studies of barriers in the Middle River will be used to determine the need and
design for 2014 barrier studies in the Lower River (FERC 2013a). Other studies to be conducted
in 2013 that will contribute to determining the need for barrier studies in the Lower River are
RSP 9.6 – Fish Distribution and Abundance in the Middle and Lower Rivers, RSP 8.5 – Fish and
Aquatics Instream Flow Study, RSP 6.5 – Geomorphology Study, and the Flow Routing Model
(RSP 8.5). If 2013 results, as presented in the Initial Study Report, indicate that the Project will
cause significant adverse effects on fish passage into tributaries and off-channel habitats in the
Middle River then additional study sites will be added in the Lower River in 2014, or in
subsequent study years (FERC 2013a).
7.7. Documentation of Consultation
Documentation that a draft plan and schedule were provided to FWS, NMFS, and any other
TWG participants at least 30 days prior to the due date of the plan and schedule (allowing at
least 15 days for comment); a description of how FWS’, NMFS’, or other TWG participant’s
comments are incorporated into the final plan; and an explanation for why any of FWS’,
NMFS’, or other TWG participant’s comments are not incorporated into the final plan.
This section will be completed by AEA prior to submission of the final implementation plan to
FERC.
8. REFERENCES CITED
ADF&G (1984b). Susitna Hydro Aquatic Studies, Report No.3: Aquatic habitat and instream
flow investigations, May - October 1983 (Review Draft). Chapter 6: An evaluation of
passage conditions for adult salmon in sloughs and side channels of the Middle Susitna
River. Prepared for Alaska Power Authority, Anchorage, AK.
AEA (Alaska Energy Authority). 2012. Susitna-Watana Hydroelectric Project No 14241-000.
Revised Study Plan (RSP) submitted to FERC December 2012.
—. 2013a. R2 Resource Consultants PowerPoint presentation – slide 23. Update on Habitat
Suitability Criteria Development. March 27, 2013 Technical Workgroup Meeting,
Anchorage, AK.
—. 2013b. Susitna-Watana Hydroelectric Project No 14241-000. First Year Study Report –
2012 Upper Susitna River Fish Distribution and Habitat Study - Fish Passage Barriers
Assessment.
—. 2013c. First Year Study Report – 2012 Adult Salmon Distribution and Habitat Utilization
Study.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 17 May 2013
—. 2013d. Susitna-Watana Hydroelectric Project No 14241-000. First Year Study Report –
2012 Open Water HEC-RAS Flow Routing Model.
— 2013e. Susitna-Watana Hydroelectric Project No 14241-000. Technical Memorandum.
Selection of Focus Areas and Sites in the Middle and Lower Susitna River for Instream
Flow and Joint Resources Studies – 2013 -2014. March 1, 2013.
FERC (Federal Energy Regulatory Commission). Office of Energy Projects. 2013a. February
01, 2013 Study Plan Determination for the Susitna-Watana Hydroelectric Project No
14241-000. Federal Energy Regulatory Commission.
— . 2013b. April 01, 2013 Study Plan Determination for the Susitna-Watana Hydroelectric
Project No 14241-000. Federal Energy Regulatory Commission.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 18 May 2013
9. TABLES
Table 1. Tally of off-channel habiats and tributary deltas in Middle River Focus Areas.
Focus
Area
Side
Channel
Side
Slough
Upland
Slough Backwater
Tributary
Mouth Total
104 7 2 1
1 11
113 2 1 2 5
115 1
3 1 1 6
128 8 1 1
1 11
138 3 1 2
6
141 1
1 1 1 4
144 6 1 2
1 10
151
1 1
173 4 3 2
2 11
184 2
2
Total 34 8 13 2 10 67
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 19 May 2013
Table 2. Named and unnamed tributaries in the Middle River selected for fish passage barrier investigation.
Project
Rivemile
(PRM)
Tributary Name Geomorphic
Reach
Focus
Area
Intensive
Study in
Focus
Area
Identify and
Locate Potential
Barriers in ZHI1
Documented
in
Anadromous
Waters
Catalog
Historical
Data
Available
Proposed for
FDA Fish
Sampling in
2013
Approximate
Length of
ZHI1 (mi)
Drainage Area
(mi2)
184.6 Tsusena Creek MR-2 2012 X Yes 145.3
179.3 Fog Creek MR-2 2012 X X Yes 144.1
174.3 Unnamed MR-2 FA173 X 2012 No
173.8 Unnamed MR-2 FA173 X 2012 Possible
164.8 Devil Creek MR-4 2012 X Yes 74.8
160.5 Chinook Creek MR-4 2012 X X Yes 24.7
155.9 Cheechako Creek MR-4 2012 X X Yes
152.3 Portage Creek MR-5 FA151 X X X Yes 0.19 178.6
148.3 Jack Long Creek MR-6 X X X Yes 0.03
144.6 Unnamed MR-6 FA144 X Yes 0.01
142.1 Indian River MR-6 FA141 X X X Yes 0.14 86.2
140.1 Gold Creek MR-6 X X X Yes 0.15 23.7
134.3 Fourth of July
Creek
MR-6 X X X Yes 0.12
134.1 Sherman Creek MR-6 X X X Yes 0.02
128.1 Skull Creek MR-6 FA128 X X X Yes 0.04
127.3 Fifth of July Creek MR-6 X X X Yes 0.01
124.4 Deadhorse Creek MR-6 X X X Yes 0.18 6.5
121.4 Little Portage
Creek
MR-7 X X X Yes 0.12 2.4
120.2 McKenzie Creek MR-7 X X X Yes 0.02 2.3
119.7 Lower McKenzie
Creek
MR-7 X X Yes 0.16
117.2 Lane Creek MR-7 X X X Yes 0.11 10.4
115.4 Unnamed MR-7 FA115 X Yes 0.12
115.0 Gash Creek MR-7 FA 113 X X X Yes 0.01
114.9 Slash Creek MR-7 FA 113 X X X Yes 0.02
113.7 Unnamed MR7 FA 113 X
110.5 Chase Creek MR-7 X X X Yes 0.17
105.1 Whiskers Creek MR-8 FA104 X X X Yes 0.33 17.2
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 20 May 2013
10. FIGURES
Figure 1a. Three potential impediment areas (Impediments 1, 2, and 3) to fish passage on the Susitna River located between Portage and Devil creeks
at the top end of the Middle River Segment (AEA 2013c).
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 21 May 2013
Figure 1b. Example of a location within Impediment area 1 where a velocity barrier could be created at a high river discharge. Photo at PRM 154.8,
September 11, 2012, at 11,600cfs (provisional) at Gold Creek.
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 22 May 2013
Figure 2. Proposed HSC curve development priority (AEA 2013a).
Agency Review Draft – Fish Passage Barrier Assessment Implementation Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 23 May 2013
Figure 3. Example of proposed winter fish habitat use sampling sites at the Skull Creek Complex in the Middle Susitna River Segment (AEA 2013e).
Revised Study Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 24 May 2013
Figure 4. Predicted stage hydrographs in the Susitna River at Gold Creek (USGS 15292000) under Pre-
Project and Maximum Load Following OS-1 conditions during the week of January 8 to 14, 1984. Actual
results may differ from those depicted as a result of ice formation in the river (AEA 2013d).
Revised Study Plan
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 25 May 2013
Figure 5. Conceptual layout of 2-D coarse and fine mesh modeling within the proposed Whiskers Slough Focus Area.