HomeMy WebLinkAbout3.0 Grant Lk Fisheries Assessment Final Report June 2014 FINAL
Grant Lake Hydroelectric Project (FERC No. 13212)
Aquatic Resources Study – Grant Creek, Alaska
Fisheries Assessment Report
Prepared for
Kenai Hydro, LLC
Prepared by
Mark D. Miller and John R. Stevenson
BioAnalysts, Inc.
June 2014
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 i June 2014
TABLE OF CONTENTS
1 Introduction ........................................................................................................................... 1
1.1 Proposed Project Description ........................................................................................... 1
1.2 Overall Goals Identified During Project Scoping ............................................................ 5
1.3 Existing Information ........................................................................................................ 5
1.3.1 Pre-2009 Studies ....................................................................................................... 5
1.3.1.1 Grant Creek Fish Resources .............................................................................. 6
1.3.1.2 Grant Lake Fish Resources ................................................................................ 6
1.3.1.3 Instream Flow .................................................................................................... 7
1.3.2 2009 and 2010 Aquatic Resources Studies ............................................................... 7
1.3.2.1 Fish Resources ................................................................................................... 7
1.3.2.2 Instream Flow .................................................................................................. 11
1.3.3 Need for Additional Information ............................................................................ 11
2 Study Objectives .................................................................................................................. 11
2.1 Grant Creek Salmon Spawning Distribution and Abundance ........................................ 12
2.1.1 Salmon Escapement to Grant Creek – Relative Species Abundance ..................... 12
2.1.2 Distribution of Spawning Salmon in Grant Creek .................................................. 12
2.2 Grant Creek Resident and Rearing Fish Abundance and Distribution .......................... 12
2.2.1 Adult Rainbow Trout Abundance, Distribution, and Spawning in Grant Creek .... 13
2.2.2 Resident and Rearing Fish Use of Reach 5 ............................................................. 13
2.2.3 Resident and Rearing Fish Use of Open Water Habitats in Lower Grant Creek .... 13
2.3 Trail Lake Narrows Fish and Aquatic Habitats .............................................................. 13
3 Study Area ............................................................................................................................ 14
3.1 Grant Creek .................................................................................................................... 14
3.2 Trail Lake Narrows ........................................................................................................ 28
4 Methods ................................................................................................................................ 29
4.1 Grant Creek Salmon Spawning Distribution and Abundance ........................................ 29
4.1.1 Salmon Escapement to Grant Creek ....................................................................... 29
4.1.1.1 Escapement Estimate: Area-under the Curve (AUC) ...................................... 30
4.1.2 Life History Characteristics .................................................................................... 32
4.1.3 Distribution of Spawning Salmon in Grant Creek .................................................. 33
4.2 Grant Creek Resident and Rearing Fish Abundance and Distribution .......................... 34
4.2.1 Adult Rainbow Trout Abundance, Distribution, and Spawning in Grant Creek .... 34
4.2.2 Resident and Rearing Fish Use of Reach 5 ............................................................. 34
4.2.3 Resident and Rearing Fish Use of Open Water Habitats in Lower Grant Creek .... 37
4.3 Trail Lake Narrows Fish and Aquatic Habitats .............................................................. 38
5 Results ................................................................................................................................... 39
5.1 Grant Creek Salmon Spawning Distribution and Abundance ........................................ 39
5.1.1 Salmon Escapement to Grant Creek – Relative Species Abundance ..................... 39
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 ii June 2014
5.1.1.1 Weir Count ...................................................................................................... 39
5.1.1.2 Escapement Estimate: Area under the curve (AUC) ....................................... 40
5.1.2 Life History Characteristics .................................................................................... 53
5.1.2.1 Run Timing ...................................................................................................... 53
5.1.2.2 Size (length and weight) .................................................................................. 53
5.1.2.3 Age Structure ................................................................................................... 54
5.1.2.4 Egg Voidance .................................................................................................. 56
5.1.3 Distribution of Spawning Salmon in Grant Creek .................................................. 57
5.1.3.1 Time of Spawning ........................................................................................... 73
5.1.3.2 Spawning Distribution ..................................................................................... 73
5.1.3.3 Spawning Habitat ............................................................................................ 75
5.2 Grant Creek Resident and Rearing Fish Abundance and Distribution .......................... 77
5.2.1 Adult Rainbow Trout Abundance, Distribution, and Spawning in Grant Creek .... 77
5.2.2 Resident and Rearing Fish Use of Reach 5 ............................................................. 79
5.2.3 Resident and Rearing Fish Use of Open Water Habitats in Lower Grant Creek .... 89
5.3 Trail Lake Narrows Fish and Aquatic Habitats ............................................................ 112
6 Conclusions ........................................................................................................................ 116
6.1 Summary of Grant Creek Research .............................................................................. 116
6.1.1 Anadromous Adult Salmonids .............................................................................. 116
6.1.2 Resident Adult Salmonids..................................................................................... 117
6.1.3 Juvenile Salmonids ............................................................................................... 119
6.1.4 Trail Lake Narrows ............................................................................................... 121
6.2 Potential Impacts Associated with the Construction and Operation of a Grant Creek
Dam 121
6.2.1 Reach 5.................................................................................................................. 123
6.2.1.1 Egg Incubation ............................................................................................... 123
6.2.1.2 Adult Spawning ............................................................................................. 123
6.2.1.3 Juvenile Rearing ............................................................................................ 123
6.2.2 Reaches 1-4 ........................................................................................................... 123
6.2.2.1 Egg Incubation ............................................................................................... 124
6.2.2.2 Adult Spawning ............................................................................................. 124
6.2.2.3 Juvenile Rearing ............................................................................................ 125
6.2.3 Global Issues ......................................................................................................... 125
7 Variances From FERC-Approved Study Plan and Proposed Modifications .............. 126
8 References .......................................................................................................................... 128
Appendices
Appendix 1: Estimating Salmonid Outmigrant Abundance at Grant Creek.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 iii June 2014
LIST OF TABLES
Table 5.1-1. Upstream, downstream and net passage of pink, Chinook, sockeye and coho salmon
across the weir in Grant Creek, 2013. ........................................................................................... 40
Table 5.1-2. Stream life estimates for the combined recovery of Floy tagged and radio tagged
Chinook, sockeye and coho salmon in Grant Creek, 2013. .......................................................... 41
Table 5.1-3. Cumulative weir counts for sockeye adjusted for a stream life of 14 days and for
fish passage at the weir on dates of visual surveys. ...................................................................... 42
Table 5.1-4. Visual counts of sockeye, Chinook and coho salmon above and below the weir in
Grant Creek, 2013. ........................................................................................................................ 44
Table 5.1-5. Escapement estimates for salmon in Grant Creek at the weir and estimated from
area-under-the curve with stream life and observer efficiency ..................................................... 52
Table 5.1-6. Run timing by week of the year for pink, Chinook, sockeye and coho salmon
assessed at the weir on Grant Creek, 2013. .................................................................................. 53
Table 5.1-7. Mean, maximum, and minimum length and weight of Chinook, sockeye and coho
salmon measured at the weir on Grant Creek, 2013. .................................................................... 54
Table 5.1-8. Age-at-return for coho, Chinook and sockeye salmon sampled in Grant Creek,
2013............................................................................................................................................... 55
Table 5.1-9. Length-at-age for returning coho salmon sampled at the Grant Creek weir in 2013.
Length (cm) was measured from mid-eye to the fork of the caudal fin. ...................................... 55
Table 5.1-10. General freshwater life history of Chinook, coho and sockeye salmon returning to
Grant Creek, 2013. ........................................................................................................................ 56
Table 5.1-11. Number of Chinook, sockeye, pink, and coho salmon recovered during carcass
surveys on Grant Creek, 2013. ...................................................................................................... 56
Table 5.1-12. Number of new redds constructed in Grant Creek by week of the year for pink,
Chinook, sockeye and coho salmon in 2013. A designation of “MS” (Mass Spawning) means
that new redds and old redds for could not be distinguished in the mass spawning aggregates. . 73
Table 5.1-13. Number and proportion of redds counted in each reach of Grant Creek for pink,
Chinook, sockeye and coho salmon in 2013. ................................................................................ 74
Table 5.1-14. The number of unique detections of radio-tagged adult salmon by species and
reach within Grant Creek. ............................................................................................................. 74
Table 5.1-15. Location of salmon redds within different channel areas of Grant Creek. ............. 75
Table 5.1-16. Location of pink, Chinook, sockeye and coho salmon redds within reaches and
aquatic habitats of Grant Creek. A designation of “NA” means that the habitat type was not
available in that reach of Grant Creek. ......................................................................................... 76
Table 5.1-17. Number of detections for radio tagged Chinook, sockeye, and coho salmon in
aquatic habitats of Grant Creek, 2013........................................................................................... 77
Table 5.2-1. Weekly passage of rainbow trout and Dolly Varden across the weir in Grant Creek,
2013............................................................................................................................................... 78
Table 5.2-2. The travel time and length of residence of radio-tagged rainbow trout detected in
Reach 5 of Grant Creek................................................................................................................. 79
Table 5.2-3. Number of minnow traps, total effort, and number of fish captured in Reach 5 of
Grant Creek from April through October 2013. ........................................................................... 83
Table 5.2-4. Number, proportion and CPUE of fish caught in Reach 5 of Grant Creek with
minnow traps from April through October 2013. ......................................................................... 83
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Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 iv June 2014
Table 5.2-5. Number of fish captured in minnow traps by month for upper Grant Creek from
April through October 2013. ......................................................................................................... 87
Table 5.2-6. The date of tagging, transmitter coding, capture method, sex, weight and length of
20 adult rainbow trout tagging in Grant Creek, Alaska 2013. ...................................................... 90
Table 5.2-7. Habitat use by location based on mobile telemetry surveys for radio-tagged rainbow
trout in Grant Creek, AK, 2014. ................................................................................................... 91
Table 5.2-8. The number of radio-tagged rainbow trout and Dolly Varden detected by reach
within Grant Creek, Alaska 2013. ................................................................................................. 95
Table 5.2-9. The date of last detection for 18 radio-tagged adult rainbow trout in Grant Creek,
Alaska, 2013. ................................................................................................................................ 96
Table 5.2-10. Number of minnow traps, total effort, and number of fish captured in lower Grant
Creek from April through October 2013. ..................................................................................... 97
Table 5.2-11. Number, proportion, and CPUE for fish caught in Lower Grant Creek from April
through October of 2013. .............................................................................................................. 97
Table 5.2-12. Number, proportion and CPUE of fish caught in lower Grant Creek with minnow
traps from April through October, 2013. ...................................................................................... 98
Table 5.2-13. Numbers of fish collected from minnow trapping in lower Grant Creek from April
through October 2013. .................................................................................................................. 99
Table 5.2-14. Number of fish captured in minnow traps in different reaches of lower Grant Creek
from April through October 2013. .............................................................................................. 100
Table 5.2-15. CPUE for fish captured in minnow traps in different reaches of lower Grant Creek
from April through October 2013. .............................................................................................. 100
Table 5.2-16. Number and density of salmonids observed during night time snorkel surveys in
lower Grant Creek in April 2013. ............................................................................................... 104
Table 5.2-17. Abundance of salmonids observed in 20-mm increments during night time snorkels
surveys in lower Grant Creek in April and May 2013. ............................................................... 105
Table 5.2-18. Number and density of salmonids observed during night time snorkel surveys in
lower Grant Creek in May 2013. ................................................................................................ 105
Table 5.2-19. The number of fish released and recovered by species for the two flow blocks and
their corresponding trap efficiencies. .......................................................................................... 107
Table 5.2-20. The number of juvenile migrants by species captured within the lower incline
plane trap, and corresponding abundance estimates and standard errors based on capture
efficiencies in Grant Creek. ........................................................................................................ 108
Table 5.3-1. Number of minnow traps, total effort, number of fish captured and CPUE in the
Trail Lake Narrows in July 2013. ............................................................................................... 112
Table 5.3-2. Number, proportion and CPUE of fish caught in the Trail Lake Narrows with
minnow traps in July 2013. ......................................................................................................... 112
Table 5.3-3. Number and proportion of catch for fish seined in beach areas of the Trail Lake
Narrows in July 2013. ................................................................................................................. 115
Table 5.3-4. Angling station and number and size and weight of rainbow trout and Dolly Varden
observed in July 2013. ................................................................................................................ 116
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 v June 2014
LIST OF FIGURES
Figure 1.1-1. Natural resources study area. ................................................................................... 3
Figure 1.3-1. Grant Creek reaches. ................................................................................................ 9
Figure 3.1-1. Aquatic habitats of Grant Creek ............................................................................. 15
Figure 3.1-2. Grant Creek mean daily flows as measured at the Reach 3 gaging station, 2013.
Flows at which the Reach 1 Distributary (190 cfs; blue line) and the Reach 2 Distributary (426
cfs; red line) begin to flow are depicted. ....................................................................................... 27
Figure 4.1-1. The A-frame weir used on Grant Creek to count adult salmon, rainbow trout and
Dolly Varden in 2013.................................................................................................................... 29
Figure 5.1-1. Observer efficiency relationships for sockeye, Chinook and coho salmon in Grant
Creek, 2013. .................................................................................................................................. 43
Figure 5.1-2. Visual surveys of Chinook salmon location in Grant Creek, 2013. ....................... 45
Figure 5.1-3. Visual surveys of coho salmon location in Grant Creek, 2013. ............................. 47
Figure 5.1-4. Visual surveys of sockeye salmon location in Grant Creek, 2013. ........................ 49
Figure 5.1-5. Plots of visual counts used to estimate area-under-the-curve for Chinook, sockeye
and coho salmon in Grant Creek, 2013. ........................................................................................ 51
Figure 5.1-6. Spawning locations for Chinook salmon in Grant Creek, 2013. ............................ 59
Figure 5.1-7. Spawning locations for coho salmon in Grant Creek, 2013. .................................. 61
Figure 5.1-8. Spawning locations for sockeye salmon in Grant Creek, 2013. ............................ 63
Figure 5.1-9. Spawning locations for pink salmon in Grant Creek, 2013. .................................. 65
Figure 5.1-10. Mobile telemetry detections for radio tagged Chinook salmon in Grant Creek,
2013............................................................................................................................................... 67
Figure 5.1-11. Mobile telemetry detections for radio tagged sockeye salmon in Grant Creek,
2013............................................................................................................................................... 69
Figure 5.1-12. Mobile telemetry detections for radio tagged coho salmon in Grant Creek, 2013.
....................................................................................................................................................... 71
Figure 5.2-1. Mobile telemetry detections for radio tagged rainbow trout in Reach 5 of Grant
Creek, 2013. .................................................................................................................................. 81
Figure 5.2-2. Location of minnow traps placed in Grant Creek, 2013. ....................................... 85
Figure 5.2-3. Catch-per-unit-effort (CPUE) for juvenile Chinook, coho, Dolly Varden and
rainbow trout from minnow trapping in upper Grant Creek from April through October, 2013. 88
Figure 5.2-4. The length-weight relationship of radio-tagged adult rainbow trout in Grant Creek,
2013............................................................................................................................................... 90
Figure 5.2-5. Mobile telemetry detections for radio tagged rainbow trout in Reach 1-4 of Grant
Creek, 2013. .................................................................................................................................. 93
Figure 5.2-6. CPUE for juvenile Chinook, coho, Dolly Varden and rainbow trout from minnow
trapping in lower Grant Creek from April through October, 2013. .............................................. 99
Figure 5.2-7. CPUE for fish captured in minnow traps placed in backwater, side channel and
mainstem areas of lower Grant Creek from April through October 2013. ................................. 101
Figure 5.2-8. CPUE for salmonids captured in minnow traps placed in backwater, side channel
and mainstem areas of lower Grant Creek from April through October 2013. .......................... 102
Figure 5.2-9. CPUE for salmonids captured in minnow traps placed in different habitat unit
types of lower Grant Creek from April through October, 2013. ................................................ 103
Figure 5.2-10. The distribution of size by date for Chinook, coho, rainbow trout, and Dolly
Varden captured in the lower incline plane trap, Grant Creek, Alaska 2013. ............................ 110
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 vi June 2014
Figure 5.2-11. Emigration timing for Chinook, coho, and Dolly Varden juveniles at the Lower
Incline Plane Trap in Grant Creek, Alaska, 2013. Estimated or extrapolated values are
highlighted red. ........................................................................................................................... 111
Figure 5.3-1. Location of minnow traps and angling stations in the Trail Lake Narrows, 2013.
..................................................................................................................................................... 113
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 vii June 2014
Acronyms and Abbreviations
ADF&G Alaska Department of Fish & Game
AEIDC Arctic Environmental Information Data Center
AUC area-under-the-curve
AWC Anadromous Waters Catalog
cfs cubic feet per second
CIAA Cook Inlet Aquaculture Association
CPUE catch per unit effort
DLA Draft License Application
FERC Federal Energy Regulatory Commission
FL fork length
GPS Global Positioning System
IFIM Instream Flow Incremental Methodology
KHI Kenai Hydro, Inc.
KHL Kenai Hydro, LLC
LA License Application
LWD large woody debris
mm millimeter
MW megawatt
NAVD 88 North American Vertical Datum of 1988
NGVD 29 National Geodetic Vertical Datum of 1929
NOI Notice of Intent
PAD Pre-Application Document
PM&E protection, mitigation and enhancement
Project Grant Lake Hydroelectric Project
TWG Technical Working Group
USGS U.S. Department of the Interior, Geological Survey
WUA weighted usable area
Note: Measurements within this document are given in metric units with the exception of
Section 1.1 (the description of the proposed project). Measurements within that section are given
in English units in order to be consistent with other Grant Creek resource documents.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 viii June 2014
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FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 1 June 2014
Aquatic Resources Study – Grant Creek, Alaska
Fisheries Assessment Report
Grant Lake Hydroelectric Project (FERC No. 13212)
1 INTRODUCTION
On August 6, 2009, Kenai Hydro, LLC (KHL) filed a Pre-Application Document (PAD; KHL
2009), along with a Notice of Intent (NOI) to file an application for an original license, for a
combined Grant Lake/Falls Creek Project (Federal Energy Regulatory Commission [FERC] No.
13211/13212 [“Project” or “Grant Lake Project”]) under Part I of the Federal Power Act (FPA).
On September 15, 2009, FERC approved the use of the Traditional Licensing Process (TLP) for
development of the License Application (LA) and supporting materials. As described in more
detail below, the proposed Project has been modified to eliminate the diversion of water from
Falls Creek to Grant Lake. The Project will be located near the community of Moose Pass,
Alaska in the Kenai Peninsula Borough, approximately 25 miles north of Seward, Alaska and
just east of the Seward Highway (State Route 9).
The fish assessment portion of the Aquatic Resources Study Plan (KHL 2013) was designed to
address information needs identified in the PAD, during the TLP public comment process, and
through early scoping conducted by FERC. This study report presents existing information
relative to the scope and context of potential effects of the Project. This information will be used
to analyze Project impacts and propose protection, mitigation, and enhancement (PM&E)
measures in the draft and final LAs for the Project.
1.1 Proposed Project Description
The Project is located near the community of Moose Pass in the Kenai Peninsula Borough,
approximately 25 miles north of Seward and just east of the Seward Highway. It lies within
Section 13 of Township 4 North, Range 1 West; Sections 1, 2, 5, 6, 7, and 18 of Township 4
North, Range 1 East; and Sections 27, 28, 29, 31, 32, 33, 34, 35, and 36 of Township 5 North,
Range 1 East, Seward Meridian (U.S. Geological Survey [USGS] Seward B-6 and B-7
Quadrangles).
The proposed Project would be composed of an intake structure at the outlet to Grant Lake, a
tunnel, a surge tank, a penstock, and a powerhouse. It would also include a tailrace detention
pond, a switchyard with disconnect switch and step-up transformer, and an overhead or
underground transmission line. The preferred alternative would use approximately 15,900 acre-
feet of water storage during operations between pool elevations of approximately 692 and up to
703 feet North American Vertical Datum of 1988 (NAVD 88)1.
1 The elevations provided in previous licensing and source documents are referenced to feet mean sea level in
NGVD 29 [National Geodetic Vertical Datum of 1929] datum, a historical survey datum. The elevations presented
in the Grant Lake natural resources study reports are referenced to feet NAVD 88 datum, which results in an
approximate +5-foot conversion to the NGVD 29 elevation values.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 2 June 2014
An intake structure would be constructed approximately 500 feet east of the natural outlet of
Grant Lake. An approximate 3,200-foot-long, 10-foot diameter horseshoe tunnel would convey
water from the intake to directly above the powerhouse at about elevation 628 feet NAVD 88.
At the outlet to the tunnel a 360-foot-long section of penstock will convey water to the
powerhouse located at about elevation 531 feet NAVD 88. An off-stream detention pond will be
created to provide a storage reservoir for flows generated during the rare instance when the units
being used for emergency spinning reserve are needed to provide full load at maximum ramping
rates. The tailrace would be located in order to minimize impacts to fish habitat by returning
flows to Grant Creek upstream of the most productive fish habitat.
Two concepts are currently being evaluated for water control at the outlet of Grant Lake. The
first option would consist of a natural lake outlet that would provide control of flows out of
Grant Lake. A new low level outlet would be constructed on the south side of the natural outlet
to release any required environmental flows when the lake is drawdown below the natural outlet
level. The outlet works would consist of a 48-inch diameter pipe extending back into Grant
Lake, a gate house, regulating gate, controls and associated monitoring equipment. The outlet
would discharge into Grant Creek immediately below the natural lake outlet.
In the second option, a concrete gravity diversion structure would be constructed near the outlet
of Grant Lake. The gravity diversion structure would raise the pool level by a maximum height
of approximately 2 feet (from 703 to 705 feet NAVD 88), and the structure would have an
overall width of approximately 120 feet. The center 60 feet of the structure would have an
uncontrolled spillway section with a crest elevation at approximately 705 feet NAVD 88.
Similar to the first option, a low level outlet would be constructed on the south side of the natural
outlet to release any required environmental flows when the lake is drawn down below the
natural outlet level. The outlet works would consist of a 48-inch diameter pipe extending back
into Grant Lake, a gate house a regulating gate, controls, and associated monitoring equipment.
The outlet would discharge into Grant Creek immediately below the diversion structure.
Figure 1.1-1 displays the global natural resources study area for the efforts undertaken in 2013
and 2014 along with the likely location of Project infrastructure and detail related to land
ownership in and near the Project area. Further discussions related to specifics of the
aforementioned Project infrastructure along with the need and/or feasibility of the diversion dam
will take place with stakeholders in 2014 concurrent with the engineering feasibility work for the
Project. Refined Project design information will be detailed in both the Draft License
Application (DLA) and any other ancillary engineering documents related to Project
development. The current design includes two Francis turbine generators with a combined rated
capacity of approximately 5.0 megawatts (MW) with a total design flow of 385 cubic feet per
second (cfs). Additional information about the Project can be found on the Project website:
http://www.kenaihydro.com/index.php.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 5 June 2014
1.2 Overall Goals Identified During Project Scoping
The goals of the study efforts described in this report were to provide baseline information; those
data, in conjunction with existing information will be used to develop potential alternative flow
regimes, which in turn will be assessed to determine potential Project impacts on aquatic
resources. These impact assessments will identify potential protection, mitigation, and
enhancement measures to be presented in the draft and final LAs.
The goals of this suite of studies were to provide supporting information on the potential
resource impacts of the proposed Project that were identified during development of the PAD,
public comment, and FERC scoping for the LA, as follows:
• Impact of Project operation on sediment transport (relative to the availability of
spawning gravels) due to changes in flow in Grant Creek.
• Impact of Project operation (fluctuating lake levels in Grant Lake, changes in
seasonal flow in Grant Creek, reduced flows between the dam and powerhouse on
Grant Creek) on fish abundance and distribution.
• Impact of Project construction and operation on biological productivity and
abundance of fish food organisms in Grant Creek and Grant Lake.
• Impact of Project intake structure operation on fish populations.
• Impact of Project construction on fish habitat in Grant Creek.
• Impact of Project facilities (increased access) on fish populations due to potential
increased recreational fishing.
• Impact of Project construction and operation on commercial, sport, and subsistence
fisheries supported by the Kenai River watershed.
Specific objectives and quantitative objectives are presented below for each individual study
component.
1.3 Existing Information
Information relating to aquatic resources has been collected during previous investigations into
the potential development of hydroelectric generation at Grant Creek as well as during pre-
licensing studies conducted by KHL in 2009 and early 2010. In the following sub-sections,
Sections 1.3.1 and 1.3.2, we describe the findings from these studies.
1.3.1 Pre-2009 Studies
Previous FERC licensing efforts in the 1960s and 1980s for a proposed hydroelectric project at
Grant Lake included studies of fish resources in Grant Lake and Grant Creek. Arctic
Environmental Information and Data Center (AEIDC 1983) conducted fish sampling from 1981
to 1982 as part of a comprehensive environmental baseline study effort and the USFWS (1961)
conducted limited sampling from 1959 to 1960. An instream flow study was completed in 1987
as part of a preliminary FERC LA prepared by Kenai Hydro, Inc. (not related to the current
Kenai Hydro, LLC; Envirosphere 1987, KHI 1987a, and KHI 1987b).
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 6 June 2014
1.3.1.1 Grant Creek Fish Resources
Both anadromous and resident fish are present in Grant Creek, including salmon, trout, and other
species. Spawning Chinook (Oncorhynchus tshawytscha), sockeye (Oncorhynchus nerka), and
coho (Oncorhynchus kisutch) salmon, as well as rainbow trout (Oncorhynchus mykiss) and
Dolly Varden (Salvelinus malma) are found in the lower reaches of Grant Creek (Ebasco 1984;
Johnson and Klein 2009). Rearing Chinook, coho and rainbow trout are also present (Ebasco
1984, Johnson and Klein 2009). Round whitefish (Prosopium cylindraceum) and arctic grayling
(Thymallus arcticus) were caught during angling surveys but are not assumed to spawn in Grant
Creek (Ebasco 1984).
Upper Grant Creek is impassable to salmon one mile upstream of the mouth (Johnson and Klein
2009), with most fish habitat concentrated within the lower portion of stream. Habitat for
juvenile fish exists mainly in stream margins, eddies, deep pools, and side channels offering
reduced velocities (Ebasco 1984). Substrate material is coarse throughout the entire length of the
creek due to high water velocity that tends to wash away smaller gravels (Ebasco 1984). Isolated
areas of suitable spawning gravels occur in the lower half of the stream (Ebasco 1984).
Periodic minnow trapping on Grant Creek from July 1959 through January 1961 captured
juvenile Chinook salmon, coho salmon, Dolly Varden char, and sculpin (extent of sampling area
unknown; USFWS 1961). Minnow trapping and electrofishing in the lower reaches of Grant
Creek for week-long periods in October 1981 and March, May, June, and August 1982 yielded
higher catches of trout, salmon, and Dolly Varden in the fall and summer than in winter and
spring (AEIDC 1983). Catches of Dolly Varden were generally most abundant in the minnow
traps, followed by juvenile Chinook, juvenile rainbow trout, and juvenile coho. Juvenile
Chinook were the most commonly caught fish during electrofishing surveys (Ebasco 1984).
Ebasco (1984) estimated that Grant Creek supported 250 Chinook spawners and 1,650 sockeye
spawners. The stream was also estimated to support 209 8-inch “trout” (including Dolly Varden
and rainbow trout) (Ebasco 1984). Spawning coho were not observed (Ebasco 1984) but have
been recorded as being present at unknown levels in the stream by the Anadromous Waters
Catalog (AWC) published by the Alaska Department of Fish and Game (Johnson and Klein
2009). Maximum counts from intermittent stream surveys by the Alaska Department of Fish &
Game (ADF&G) were 76 Chinook (1963) and 324 (1952) sockeye salmon.
1.3.1.2 Grant Lake Fish Resources
Sampling during 1981-1982 found no fish in any of the tributaries to Grant Lake (AEIDC 1983).
Sculpin and three-spine stickleback were the only fish found to inhabit Grant Lake. A series of
impassable falls near Grant Lake’s outlet prevents colonization of the lake by salmonids via
Grant Creek (Ebasco 1984). Density of three-spine stickleback was ten times higher in the lower
basin than the upper basin of Grant Lake (AEIDC 1983).
Because of the impassable falls below Grant Lake’s outlet, no anadromous fish species occur in
Grant Lake and its tributaries (USFWS 1961, AEIDC 1983, Ebasco 1984), and Grant Lake is not
included in the AWC (Johnson and Daigneault 2008). Grant Lake appears to support only
resident populations of sculpin–including Slimy sculpin (Cottus cognatus) and Coast Range
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sculpin (Cottus aleuticus) and three-spine stickleback (Gasterosteus aculeatus) (AEIDC 1983,
USFWS 1961, Johnson and Klein 2009).
Although Sisson (1984) reported that Dolly Varden and a few rainbow trout occupied Grant
Lake, subsequent investigations (USFWS 1961, AEIDC 1983, Marcuson 1989) have
documented only sculpin and stickleback. From 1983-1986, coho salmon fry were stocked in
Grant Lake by ADF&G, with limited success, though some enhanced returns to Grant Creek
were recorded (Marcuson 1989).
1.3.1.3 Instream Flow
Environmental analyses that emphasized the relationship between stream flow and aquatic
habitats (instream flow studies) were conducted on Grant Creek in the 1980s by Kenai Hydro,
Inc. (KHI; unrelated to Kenai Hydro, LLC). These documents were compiled in support of a LA
for hydropower development on Grant Creek. The documents include reports and written
communications between KHI and state and federal agencies in 1986 and 1987 relative to a
FERC LA for the proposed Grant Lake Hydroelectric Project (FERC No. 7633-002). Included
were draft and final reports of a limited but complete Instream Flow Incremental Methodology
(IFIM) investigation and negotiated minimum instream flows and ramping rates (Envirosphere
1987, KHI 1987a, and KHI 1987b). A technical memorandum was drafted and shared with the
Instream Flow Technical Working Group (TWG) participants in 2009 detailing the results of the
previous instream flow study efforts (HDR 2009a).
1.3.2 2009 and 2010 Aquatic Resources Studies
The 2009 aquatic resources study program was implemented to assist with the current FERC
licensing effort. After collaboration with stakeholders, emphasis was placed on updating existing
information, acquiring more complete data required for specific issue analysis, and providing
background information needed to develop more focused studies after initiation of the formal
FERC licensing process. The studies were continued in 2010 but the program was discontinued
in July, 2010 after further stakeholder collaboration in an effort to revise the study plans and
make them more quantitative in nature.
1.3.2.1 Fish Resources
The 2009 fisheries study (HDR 2009b) focused on the following objectives:
• Determine the relative abundance and distribution of juvenile fish in Grant Creek.
• Determine the relative abundance and distribution of resident Dolly Varden and
rainbow trout in Grant Creek.
• Estimate abundance and run timing of spawning salmon.
• Estimate abundance and run timing of spawning adult resident fish.
• Determine fish presence and distribution in Grant Lake.
Consistent with studies conducted by AEIDC (1983), Grant Creek was divided into study
Reaches 1 through 6 (Figure 1.3-1). Reaches 1 through 4 were roughly equal in length and
Reaches 5 and 6 were established based on geomorphologic characteristics (HDR 2009b).
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Relative abundance and distribution of juvenile fish were determined by minnow trapping and
calculating the catch-per-unit-effort (CPUE) for each reach. Reaches 1 through 4 were sampled
relatively evenly, with nine to 13 minnow traps per reach. Terrain was difficult to access in
Reaches 5 and 6, so these reaches were sampled less frequently and with only three and five
sites, respectively. A total of 50 baited minnow traps were placed throughout the creek in
Reaches 1 through 6; mesh size was 0.6 cm. The creek was sampled monthly, with the exception
of Reach 6, which was sampled in June and August only. Dolly Varden were found to be the
most abundant species in Grant Creek and distributed throughout Grant Creek Reaches 1 through
5, although they had a greater relative abundance in Reaches 4 and 5. Coho salmon was the next
most abundant species and individuals were distributed throughout Reaches 1 through 5.
However, coho appeared to have the greatest relative abundance in Reach 1. Chinook salmon
was the next most abundant species. There was a noticeable decrease in Chinook abundance in
upstream reaches, and they were not caught above Reach 4. Other fish present in small numbers
were sockeye salmon, rainbow trout, sculpin, and three-spine stickleback. Most salmon captured
were young-of-the-year with few larger juveniles present (HDR 2009b).
Relative abundance of larger size resident salmonids (i.e., rainbow trout and Dolly Varden) was
determined by calculation of angling CPUE (HDR 2009b). A total of 18 angling sites were
established along the creek, and each site was fished for 30 minutes approximately every 10
days, from early June through late September. Rainbow trout (n = 68) were found to be more
abundant than Dolly Varden (n = 9) and were caught throughout the creek, although their relative
abundance was higher in Reaches 3 through 5 than in Reaches 1 and 2. Dolly Varden were
captured in Reaches 1, 2, and 3; their relative abundance was highest in Reach 1.
This study was also aimed at determining the timing of spawning of adult resident fish; however,
it appeared that spawning, if present, occurred before or after the 2009 study period, since little
evidence of spawning fish was seen (HDR 2009b). Rainbow trout angling studies were
continued in the spring and early summer of 2010 to confirm the presence of spawning and
determine fish numbers. The progression of reproductive condition and the presence of adult
rainbow trout in spawning condition confirmed that spawning did occur in Grant Creek in 2010.
Capture success was too low to allow population estimates. Adult rainbow trout were observed
in the upper portions of the canyon reach.
Abundance and run timing of spawning anadromous fish was estimated through data collected
during foot surveys (HDR 2009b). Foot surveys occurred approximately every 10 days
beginning in mid-June and ending in late September. Both sockeye and Chinook salmon were
seen in the lower five reaches. Chinook salmon reached Grant Creek first around the beginning
of August. Sockeye salmon did not arrive until the end of August. Escapement of Chinook
salmon was estimated to be 231 fish, and escapement of sockeye salmon was estimated at 6,293.
Fish distribution and presence in Grant Lake and its tributaries were assessed using minnow
traps, electrofishing, and gill nets (HDR 2009b). Sampling occurred at nine gill netting sites, 18
electrofishing sites, and 28 minnow trapping sites. Three-spine stickleback was the dominant
species in the lake followed by sculpin. No other species of fish was captured (HDR 2009b).
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1.3.2.2 Instream Flow
The collaborative process for a study of “instream flow” effects in Grant Creek was initiated in
2009 (HDR 2009b). The primary goal of the 2009 instream flow study program was to establish
a TWG consisting of state and federal resource agency staff, KHL staff, and interested members
of the local community. Once established, the TWG met three times during the 2009 study
season to review the results of the 2009 aquatic baseline study efforts, discuss and agree upon an
acceptable instream flow evaluation method, and request additional information to support the
selection of an instream flow method (HDR 2009b).
As part of the instream flow study, and at the request of the TWG, a sampling event was
conducted from June 23-25, 2009 on Grant Creek to characterize the types of aquatic habitats
used by resident fish and rearing fish (HDR 2009b). Aquatic habitat was described at each
sample site by recording macro-, meso-, and micro- habitat characteristics. During the June
sampling event, snorkeling was the primary method used to document fish presence.
Electrofishing was used primarily to confirm species identification and calibrate fish length
estimates (HDR 2009b).
1.3.3 Need for Additional Information
Early study programs and the 2009-2010 baseline study program conducted by KHL have
provided a significant amount of background information regarding aquatic resources in the
Project area. Following analysis of the 2009 and 2010 study results, information gaps were
identified for further study to support the FERC licensing process. The field studies conducted
in 2013 were intended to provide information on the following general topics. Specific
objectives for study components will be described below for each component.
• Juvenile fish use of winter habitats.
• Better definition of fish use of micro-habitats and overall species composition and
relative abundances in Reaches 1 through 4.
• Extent of rainbow trout spawning in Grant Creek.
• Use of Reach 5 by juvenile and adult fish, with additional emphasis on spawning
Chinook salmon use of Reach 5.
• Delineation of aquatic habitats available in Grant Creek; identify key habitats for fish
and describe and distinguish the factors that may influence fish use of the key habitats
over those habitat units not occupied by fish in Grant Creek.
• Estimation of salmon spawning escapement in Grant Creek.
• Examination of how important individual habitat units may be affected by changes in
flow due to the operation of the proposed Project using instream flow assessment
methods.
• Fish resources and habitat use of the Trail Lake Narrows at the proposed bridge site.
2 STUDY OBJECTIVES
Study objectives were developed for the 2013 research period based on existing data, and data
gaps identified through consultation with the Stakeholders. Most objectives were a continuation
of the 2009 and 2010 research effort; while other objectives were the result of additional
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stakeholder consultation. The objectives encompass adult and juvenile anadromous salmonids,
as well as adult and juvenile resident species. The following is a brief description of the 2013
study objectives. The methods employed to achieve these objectives are discussed in detail in
Section 4.
2.1 Grant Creek Salmon Spawning Distribution and Abundance
The purpose of this study component was to characterize spawning salmon distribution, run
timing, and relative abundance in Grant Creek. This study effort consisted of two principal
components and several subcomponents:
• Use of a counting weir to obtain a direct count of all salmon entering Grant Creek
during the open water season.
o Weir counts were compared to counts from foot surveys similar to those
conducted during 2009 to calibrate earlier surveys and obtain an estimate of
observer error when viewing fish from the stream bank.
• A radio telemetry study to assess the spawning distribution of Chinook, sockeye, and
coho salmon, with emphasis on Reach 5 (Canyon Reach).
2.1.1 Salmon Escapement to Grant Creek – Relative Species Abundance
• Assessment of numbers and species of salmon in Grant Creek.
• Identify key species and critical time periods for environmental assessment.
• Identify key species and critical time periods as may be applied to design of Project
mitigation measures.
• Calibration of escapement estimates from foot surveys conducted in 2009.
• The primary objective is to obtain a nearly complete count of salmon of each species
entering Grant Creek.
2.1.2 Distribution of Spawning Salmon in Grant Creek
• Identify critical spawning habitats as required for general assessment of Project
impacts.
• Identify habitat areas appropriate for use in instream flow analysis.
• Provide input for project mitigation needs by identifying sensitive stream segments.
2.2 Grant Creek Resident and Rearing Fish Abundance and Distribution
The purpose of this study component was to characterize distribution and abundance of all
species of resident and rearing fish and run timing of rainbow trout in Grant Creek. This study
effort consisted of the following components:
• Weir inventory and telemetry study to assess run timing, relative abundance, and
spawning habitat location for rainbow trout.
• Investigation of juvenile fish presence in Reach 5 of Grant Creek using minnow traps
and other sampling techniques.
• Minnow trap and video sampling in late winter/early spring at likely overwintering
habitats to determine salmonid overwintering presence in Grant Creek.
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• Snorkel sampling to determine fish use of meso-habitats in Grant Creek.
2.2.1 Adult Rainbow Trout Abundance, Distribution, and Spawning in Grant
Creek
• Assessment of relative numbers of rainbow trout in Grant Creek.
• Identification of sensitive time periods for environmental assessment.
• Identify important spawning and feeding habitats for general assessment of project
impacts.
• Provide input for Project mitigation needs by identifying sensitive stream segments.
• Obtain a count of adult rainbow trout entering Grant Creek during the open water
season.
• Determine distribution of trout by tracking radio-tagged fish.
2.2.2 Resident and Rearing Fish Use of Reach 5
• Assessment of rearing fish use of habitats within Reach 5.
• Assessment of the juvenile fish productivity of Reach 5 relative to the remainder of
Grant Creek.
• Assessment of the need for mitigation measures within Reach 5.
• Use of an inclined plane trap to monitor outmigrants from Reach 5.
2.2.3 Resident and Rearing Fish Use of Open Water Habitats in Lower Grant
Creek
• Assessment of rearing fish use of habitats within lower Grant Creek as required for
project impact assessment.
• Assessment of the juvenile fish productivity of Reaches 1-4 relative to the remainder
of Grant Creek.
• Assessment of the need for mitigation measures within Lower Grant Creek.
• Selection of high fish use areas for incorporation in the instream flow study.
• Obtain a count of adult rainbow trout, Dolly Varden, and other resident species
entering Grant Creek during the open water season.
• Use an inclined plane trap to monitor outmigrants from Reach 5.
2.3 Trail Lake Narrows Fish and Aquatic Habitats
• Determine fish use in the vicinity of the proposed access road bridge crossing of Trail
Lake Narrows in order to minimize impact to aquatic resources potentially resulting
from bridge design, construction timing, and construction methodology.
• Determine habitat use to optimize bridge location and design.
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3 STUDY AREA
3.1 Grant Creek
Consistent with studies conducted by AEIDC (1983) and KHL (HDR 2009b), Grant Creek was
divided into study Reaches 1 through 6. Reaches 1 through 4 were roughly 0.125 mile each in
length and Reaches 5 and 6 were established based on geomorphologic characteristics, and were
collectively about 0.5 miles in length (HDR 2009b). Aquatic habitats in reaches 1-5 were
documented within the efforts of the IFIM team to help quantify and describe the distribution of
habitats in Grant Creek, 2013 (McMillen, LLC 2014; Figure 3.1-1). The material is presented
here to describe the study area followed by a brief description of reaches 1-5 on Grant Creek.
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Reach 1, which extends approximately 0.125 miles upstream of the confluence of Grant Creek,
includes a small distributary off the right bank. The distributary becomes watered when Grant
Creek flows exceed 190 cfs (Figure 3.1-2). This channel consists of pools and riffles that
provided habitat for juvenile salmonids, as well as some small pockets of spawning gravels. The
mainstem portion of Reach 1 includes pool and riffle habitat at lower flows, but becomes more
turbulent as flows increase. Reach 1 also contains suitable gravels and cobbles for salmonid
spawning. Reach 1 contains some pool habitat for adult salmon staging.
Figure 3.1-2. Grant Creek mean daily flows as measured at the Reach 3 gaging station, 2013. Flows at
which the Reach 1 Distributary (190 cfs; blue line) and the Reach 2 Distributary (426 cfs; red line) begin
to flow are depicted.
Reach 2 consists primarily of turbulent fast water riffle habitat, but does have some unique
features. A small distributary branches from the mainstem just upstream from the Reach 1/2
break on the left bank. This channel flows through a parcel of private property and empties into
Lower Trail Lake downstream of the Narrows. During its course, the channel splits into two
channels at higher flows, which rejoin downstream. This channel contains a wide variety of
habitat, including riffles, pools, glides, etc., and does have some smaller gravel deposits, which
would be suitable for resident species spawning (i.e., rainbow trout and Dolly Varden). This
channel is only watered when flows within the mainstem of Grant Creek exceed 425 cfs (Figure
3.1-2).
Upstream of this distributary within Reach 2, there are three backwater pools, which vary in size
depending on flows. Another pool immediately upstream of the Reach 1/2 break was the
location where the downstream incline plane trap was deployed, and contained both juvenile
0
200
400
600
800
1,000
1,200
4/1 4/16 5/1 5/16 5/31 6/15 6/30 7/15 7/30 8/14 8/29 9/13 9/28Flow (cfs)Date
Reach 1 Distributary
Reach 2 Distributary
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rearing habitat and suitable spawning gravels. These pool habitats were also used for adult
salmon resting and staging.
Reach 3 contains the greatest habitat diversity of all reaches within the study area. As with all
reaches, the mainstem consists primarily of turbulent fast water riffle habitat at higher flows. In
addition to the mainstem, two additional channels exist within Reach 3. Both of these channels
branch off the mainstem of Grant Creek on the left bank near the Reach 3/4 break. The larger of
the two channels is situated between the mainstem of Grant Creek and the southernmost channel,
and is referred to as the “Predominate Side Channel”. This side channel consisted primarily of
turbulent fast water riffle habitat, but does include a substantial log jam just downstream of its
diversion that creates a dammed pool. The second channel consists of a wide variety of habitat,
and includes riffles, glides and pools; this channel is referred to as the “Secondary Side
Channel”. Both channels provide rearing and spawning habitat, and become watered as soon as
the snow and ice cover melt. In 2013, flow was observed in both channels when Reach 2 and 4
mainstem flows were measured at 17 cfs.
Within the mainstem of Grant Creek, two backwater pools on the right bank provide spawning
habitat, adult staging, as well as juvenile rearing habitat. Downstream of those backwater pools,
a large scour pool exists, which provides staging and spawning for adult salmon, as well as
rearing for juveniles.
Reach 4 consists primarily of turbulent fast water riffle habitat at most flow levels. At higher
flows, a small channel diverges off the right bank of the mainstem, and rejoins the mainstem
channel downstream. At the upper portion of Reach 4, near the Reach 4/5 break, there is a scour
pool. This pool was the location of the upper incline plan trap. While spawning gravel does
exist within Reach 4, it is contained primarily in small pockets mainly downstream of large
boulders, and along stream margins.
Reach 5, which is approximately 0.5 miles long, consists primarily of turbulent cascade and step
pool habitat. During the majority of the study period, it was not possible to access much of
Reach 5, and even at lower flows only the lower section of Reach 5 could be sampled. Likewise,
access into the upper portion of Reach 5 was problematic. During the September minnow trap
sampling period, the area immediately downstream of the falls was assessed using rappelling
techniques. However, it was not possible to extend the sampling further downstream than the
access point due to dangerous flow conditions.
3.2 Trail Lake Narrows
The Trail Lake Narrows is located between Upper and Lower Trail Lakes, and is where the
Grant Creek confluence is located. The Narrows is also the location where the proposed access
road will cross the Trail Lake system. Because of the potential impacts associated with the
construction of the bridge and subsequent use of the access road on fish residing downstream of
the bridge, this location was surveyed in July 2013. The survey area included the Narrows from
the downstream edge of the Grant Creek confluence to the lower reaches of the channels flowing
to both the right and left of the island located immediately below the Narrows, as well as the
downstream shore of the island. Riffle habitat is dominant in this area from the confluence of
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Grant Creek to almost the downstream end of the island. This area contains juvenile rearing
habitat, spawning habitat and adult salmon staging habitat.
4 METHODS
During the course of the study, a number of methods were employed to accomplish the
objectives outlined in Section 2. Juvenile sampling included the daily operation of two juvenile
incline plane traps, monthly minnow trapping, snorkeling and beach seining. Adult sampling
included the daily operation of an adult picket style weir, weekly radio telemetry tracking, redd
surveys, visual surveys and carcass surveys. The remainder of this section will describe how
each survey method was conducted, and how the data were used to address each study objective.
4.1 Grant Creek Salmon Spawning Distribution and Abundance
4.1.1 Salmon Escapement to Grant Creek
A weir was placed about 150 meters upstream of the Grant Creek confluence, and was designed,
installed, and operated by Cook Inlet Aquaculture Association (CIAA). The weir was an A-
frame picket design, which was situated perpendicular to the flow (Figure 4.1-1). One and a half
meter long pickets were secured in place by two cross members (top and bottom) that were
attached to the upstream side of each A-frame. The cross members contained holes that allowed
pickets to be slid down until they rested on the stream bottom. Each picket could be removed for
cleaning or the relocation of the adult trapping facilities, which was necessary as flow levels
fluctuated. The gap between each picket was about 2.5 cm. Adult traps were placed on both sides
of the weir to allow upstream and downstream movement past the weir. A work station and
recovery/holding area were placed on the upstream side of the weir for biological sampling.
Figure 4.1-1. The A-frame weir used on Grant Creek to count adult salmon, rainbow trout and Dolly
Varden in 2013.
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The weir was checked every day, seven days per week by on-site staff living in a man camp on
the shore of Grant Creek. Weir operations began on May 23, and the weir operated continuously
except for the period from June 18 to June 22 when high flows (>969 cfs) required the removal
of numerous pickets to maintain weir integrity. Installation of 3-meter pickets became necessary
during high flows and their installation was complete on July 5 to replace shorter pickets first
installed. Prior to the installation of the 3-meter pickets, especially during high flow, water and
potentially fish could flow over the top of the weir. The weir was removed on October 24.
Hourly counts typically occurred between the hours of 0800 and 2100 each day.
Upstream and downstream passage past the weir was compiled hourly and summed to document
daily counts. Salmon escapement to Grant Creek was assessed as the sum of the daily counts for
net upstream passage. While the operation of the weir provided a daily count of fish by species
migrating upstream of the weir, it did not account for the number of fish that migrated into Grant
Creek and resided and/or spawned downstream of the weir. To attain an estimate of total
escapement within Grant Creek (both up and downstream of the weir), it was necessary to
calculate escapement using the Area-Under-the-Curve methodology (Bue et al. 1998).
4.1.1.1 Escapement Estimate: Area-under the Curve (AUC)
There were three components required to estimate salmon escapement (Ê) to Grant Creek using
area-under-the-curve methodology. The first component was to conduct systematic visual counts
within the study area while salmon were present. The second component was to provide an
estimate of the average time an individual salmon remained alive in the study area. This is
commonly called stream or survey life (Ŝ). The last component was an estimate of observer
efficiency (). A secondary objective of this study component was to apply the estimates of
stream life and observer efficiency estimated from Grant Creek in 2013 to visual counts in 2009.
To obtain an estimate of total escapement within Grant Creek (both up and downstream of the
weir), it was necessary to calculate escapement using the Area-Under-the-Curve methodology
(Bue et al. 1998), which is calculated as:
=
Where: = is an estimate of Escapement;
= is an estimate of Area-Under-the-Curve;
= is an estimate of Stream Life; and
= is an estimate of Observer Efficiency.
Area-under-the-curve (Â) was estimated using a trapezoidal approximation procedure similar to
that described in English et al (1992),
= (− )(+ )
2
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Where: ti = was the Julian date of the visual survey and
ci = was the visual count of salmon for the ith survey.
4.1.1.1.1 Stream Life
Stream life was estimated for each species of interest (i.e., Chinook, sockeye, and coho) using
Floy tags, radio tags and pooled data. It should be noted that all fish that were tagged with a
radio transmitter were also tagged with a Floy tag. The estimate of stream life in this report is
defined as the mean length of time between tagging at the weir and the time tags were recovered.
The Floy tags used in this study were a T-bar anchor tags (model FD-94 Anchor Tags) that were
individually numbered for all fish and colored for each species (Chinook-white, sockeye-yellow,
coho-red). The unique number made it possible to calculate the span of time between tagging
and the time of recovery. Floy tags were placed near the dorsal fin on the right side of the fish
with a needle inserted into the body to anchor the tag (T-bar) through the dorsal fin ray. There
were 33 Chinook, 533 sockeye, and 176 coho Floy tagged at the weir.
The radio tags used in this study were Lotek models MCFT2-3A and MCFT2-3B equipped with
mortality switches that allowed researchers to identify dead fish. All anadromous salmonids that
were radio-tagged were collected at the weir as they migrated upstream. A total of 14
frequencies in the 148 MHz range were used for the three species of anadromous salmonids and
the two species of resident salmonids radio-tagged. To minimize the likelihood of signal
collision, transmitters with four different burst rates (4.0, 4.5, 5.0, and 5.5 seconds between
transmissions) were deployed. The transmitters emitted a different code sequence once the
transmitter became stationary for 12 hours, as compared to the normal code sequence. This
signal identified dead fish. All anadromous species were gastrically radio-tagged and resident
species were surgically implanted with transmitters. Collectively, a total of 145 fish were radio-
tagged; 9 Chinook, 65 sockeye, 50 coho, 20 rainbow trout, and 1 Dolly Varden.
4.1.1.1.2 Observer Efficiency
Observer efficiency was estimated from the relationship of visual survey counts to weir counts
on Grant Creek. Observer efficiency was estimated by the slope of the linear fit of survey counts
regressed against an adjusted weir count. The adjusted weir count was the cumulative weir
counts by species on the days of visual surveys corrected for stream life and fish passage on the
day of the visual survey. Like Bue (1998), the assumption was that the relationship between the
estimated number of live salmon in a creek (independent variable-weir count) and survey counts
(dependent variable) was linear, and observers would not see salmon in a creek when none were
present (the fitted line passed through the origin).
4.1.1.1.3 Area-Under-the-Curve (Visual Surveys)
Visual surveys were used to document the number of live salmon in Grant Creek to estimate
area-under-the-curve. Visual surveys were conducted on Grant Creek from the confluence of
Trail Lake Narrows to about one half the way up the canyon in Reach 5. Visual counts in Grant
Creek were segregated as counts above the weir and by counts downstream from the weir.
Visual surveys were conducted every week (5-10 days) between the hours of 10:00-14:00 hours.
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Attempts were made to keep survey conditions fairly uniform by hour of the day, weather, and
stream conditions to make sure observer efficiency was not unduly affected. Visual counts were
rescheduled if heavy rain, severe wind or stream conditions (flooding) precluded adequate
survey conditions. Visual counts were conducted from the beginning of August until the end of
the first week of November.
In August, a crew of two biologist wearing polarized sunglasses walked upstream on each bank
of Grant Creek (total of 4 observers). The location of all observed fish was recorded on maps,
with species and number counted. Later, when flows decreased (i.e., mid-September), it was
possible at times to walk within Grant Creek at some locations during surveys.
4.1.1.1.4 Telemetry and Carcass Surveys
Mobile telemetry surveys and carcass surveys were an integral part of estimating escapement to
Grant Creek and for collecting biological information. Telemetry surveys were performed twice
per week, typically on Mondays and Thursdays. Fish locations were determined using standard
triangulation techniques (Eiler 2012). Fish locations were recorded with Global Positioning
System (GPS) waypoints and on maps of Grant Creek. During each survey, two receivers were
used and the crews split the number of frequencies monitored. Splitting the number of
frequencies monitored during a mobile survey helped to expedite the telemetry surveys.
Carcass surveys were performed each week but survey crews sampled fish opportunistically any
time they traveled within the study area. At the time of carcass recovery, date, species, sex,
location, and tag information were recorded. For females, eggs retained were noted and for all
fish the tail was removed and the carcass returned to Grant Creek.
4.1.2 Life History Characteristics
Salmon were counted and sampled at the weir and carcass surveys were conducted to document
the life history characteristics of spawning salmon in Grant Creek, 2013. Biological data needed
to document run timing, sex ratios, egg retention, age structure, genetic stock identification and
size (length and weight) were either collected at the weir or during carcass surveys. All fish
counted at the weir were identified to species and enumerate. A subsample of the fish was
sampled for specific data collection needs (biological data and tagging).
Run timing was determined by summing the number of fish passed the weir each week of the
year. The start, peak and end of a particular salmon run on Grant Creek was simply the week
when the first, greatest number and last fish passed the weir, respectively.
The sex ratio of all salmon except sockeye was determined from inspection of nearly 100 percent
of the fish past the weir. For sockeye, the sample rate was lower (70 percent) to accommodate
the greater abundance of fish at the weir. For anadromous salmon, gender was determined easily
with a quick visual assessment of each fish.
Egg retention information was collected on spawned out female carcasses by inspecting the
abdominal cavity and counting the number of eggs retained. Average egg retention was assessed
by dividing the total number of eggs retained by the number of females assessed. Prespawn
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mortalities were noted but were presumed to have died before spawning; therefore, they were not
included in the estimate.
Salmon collected at the weir were measured from mid-eye to fork length (mm) and weighed
(gm) to describe the size of returning salmon to Grant Creek. Mean and standard deviations
were generated for each species and gender.
Scale samples for Chinook and coho salmon were taken at the weir and delivered to the ADF&G
for age determination. For sockeye salmon, otoliths were extracted from 100 sockeye salmon
carcasses to prevent difficulties of age determination associated with scale reabsorption.
Sockeye otoliths were delivered to CIAA for age determination. Two methods were used to
describe age. The first method describes the total age of the fish (egg-to-spawning adult, i.e.,
gravel-to-gravel). The second method is termed the “European Method” and identifies the
number of winters the fish spent in freshwater before migrating to the ocean as well as the
number of winters the fish spent in the ocean. For example, a fish designated as 1.2 spent one
winter in freshwater and two in the ocean. A fish designated as 0.3 migrated to the ocean in its
first year and spent three winters in the ocean. Fish designated as 0.3 or 1.2 are considered 4-
year-old fish, from the same brood year.
The axillary processes from 100 sockeye, 33 Chinook, and 100 coho salmon were removed and
placed into vials for genetic analysis of returning salmon to Grant Creek. The tissue samples
were delivered to ADF&G. Analysis of these samples is not contained within this report.
4.1.3 Distribution of Spawning Salmon in Grant Creek
The distribution of spawning salmon in Grant Creek was documented during spawning (redd)
surveys and radio telemetry surveys. During redd surveys, the location and number of redds were
recorded on maps of Grant Creek. For radio telemetry surveys, the location of tagged fish were
also noted on maps of Grant Creek. The combination of both survey techniques is useful in
defining spawning habitat especially when turbidity precludes observations of spawning in
deeper water. The primary goal of these surveys was to identify sensitive spawning habitats in
Grant Creek
Redd surveys were conducted weekly during the spawning period, and were similar to visual
surveys in that crews hiked along the banks of Grant Creek, and recorded the locations of any
redds observed. Given the high turbidity levels in Grant Creek during these surveys, most redds
were located by first observing a fish, or observing digging activity. For all redds, the location
and species in attendance were noted. At some locations where a large number of redds were
constructed (i.e., spawning aggregates), it was difficult to identify individual redds. In such
cases, the number of redds was estimated based upon data from past surveys, and the number of
females defending redds.
Radio telemetry surveys were also employed to identify spawning locations. As discussed
previously, telemetry surveys were conducted twice per week, and triangulation techniques were
employed to identify the location of tagged fish. Since males often spawn with more than one
female they could reveal multiple spawning locations within the study area. Females typically
build and defend a single redd. The goal was to radio-tag three females for each male tagged.
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The location of redds and tagged fish were compiled on maps and by reach and habitat type to
describe the spawning distribution of salmon in Grant Creek.
4.2 Grant Creek Resident and Rearing Fish Abundance and Distribution
4.2.1 Adult Rainbow Trout Abundance, Distribution, and Spawning in Grant
Creek
As with the anadromous species, the weir was the foundation of rainbow trout research in Grant
Creek in 2013. The weir provided the opportunity to enumerate and capture rainbow trout for
biological sampling and tagging. Biological sampling included length-weight and scales
samples. Radio-tagged fish in turn provided information on spawning distribution and areas of
feeding. Weir counts provided information on run timing and abundance. The abundance
estimate for rainbow trout was assessed as total count of adult rainbow trout migrating upstream
of the weir and run timing was simply the distribution of daily counts of rainbow migrating
upstream past the weir.
Adult rainbow captured at the weir were assessed for spawning condition, and if determined to
be active spawners and greater than 300 millimeters (mm) in length fork length (FL), they were
surgically implanted with a radio-transmitter. Gender and spawning condition for rainbow trout
and Dolly Varden was based on professional judgment of morphological characteristics (color,
abdomen development, reproductive products, ovipositor extension, kype, etc.). For all fish,
scale samples were collected in order to determine age, and each radio-tagged fish was tagged
with a uniquely numbered Floy tag. Tagged fish were transported approximately 75 meters
upstream, and released into a quiet cove located on the right bank to facilitate recovery.
Rainbow trout captured at the weir were supplemented with fish captured through angling.
Initially, the intent was to tag a total of 30 rainbow trout and 10 Dolly Varden. However, the
weir did not become fully functional until early July when longer pickets were installed to
preclude fish passage (both up and downstream) over the weir. Therefore, it was necessary to
capture resident fish through angling efforts.
Radio-tagged trout were tracked twice per week for the duration of the study period, and their
location at the time of detection was determined using triangulation techniques. Those positions
were recorded on maps of the study area.
Redd surveys for rainbow trout were conducted at least once per week following the method
described previously for anadromous species. Researchers also checked opportunistically as they
were in the study area at least 5 days a week.
4.2.2 Resident and Rearing Fish Use of Reach 5
Due to the nearly vertical walls, steep gradient, and high flows within Reach 5, assessment of
resident and rearing fish use of this area was challenging. Sampling techniques that could be
conducted throughout the study period included minnow trapping and radio telemetry surveys.
Telemetry surveys could be conducted from the top of the canyon wall, which allowed the
survey of all of Reach 5. Minnow trapping was limited to the lower and upper portions of Reach
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5, with the upper section accessed through rappelling. Snorkeling was conducted early in the
study period (April and May), and was limited to the lower third of the canyon. Due to the
substrate in Reach 5, which consists primarily of large boulders, beach seining was not
conducted within this portion of Grant Creek.
In order to assess the use of Reach 5 by juvenile rearing fish, an incline plane trap was deployed
at the Reach 4/5 break to identify and enumerate juvenile salmonids as they migrated
downstream and out of Reach 5.
The juvenile incline plane trap was located in a scour pool immediately downstream of the
Reach 4/5 break, and was operated seven days per week, 24 hours per day unless either high
flows or debris load made operations either ineffective or too dangerous to operate. The trap was
cleaned at least twice per day and more frequently when debris became an issue. All fish
collected at the trap were removed from the live box using aquarium nets and transferred to a
18.9-liter bucket for transfer to the processing station located on the left bank. Fish were then
anesthetized in a mixture of clove oil and water (6 drops of clove oil per 3.8 liters of water),
measured (to the nearest millimeter), and weighed (to the nearest tenth of a gram), and then
recovered in fresh water. Fish were held until equilibrium was achieved, and were then released
into a low flow area within Reach 4 of Grant Creek.
Initially, the study objective was to estimate relative abundance of various salmonid juveniles
within Reach 5 using the incline plane trap; that is, if sufficient numbers were captured to
conduct efficiency trials of the trap, and in turn use a Petersen equation to estimate overall
abundance. However, it was known from previous research (HDR 2009b) that it was unlikely
that sufficient numbers of juveniles migrating downstream and out of Reach 5 would be captured
to estimate abundance. While marking and release protocols were developed and ready for use,
relatively few fish were captured during the study period. Furthermore, due to high flows during
the period of May 30 to September 19, trapping operations were terminated due to the risk of the
trap breaking free from its moorings, the risk of death and injury to captured fish, poor trapping
conditions, and the danger to the field personnel when accessing the trap. As such, the focus of
the incline plane trap once it was re-installed was to simply establish presence and enumerate the
various species collected in the trap, and to collect weight and length data.
In addition to the incline plane trap, minnow trapping and snorkeling were utilized to determine
rearing fish use of Reach 5. Due to the high flows described previously, snorkeling within Reach
5 was only possible in April and in May. Snorkel sites were selected based on likelihood of
juvenile rearing. Snorkel sites typically encompassed an entire habitat unit; that is, if the site was
within a pool, the entire pool was snorkeled unless the habitat unit exceeded 100 meters in
length, in which case a sub-sample of the habitat unit was evaluated. The number of individuals
snorkeling a given site was dependent on the size of the snorkel site, but was typically two
individuals. All sample sites were measured, which included length and at least one width, and
more if the stream width was highly variable. Measurements were used to calculate area to
provide a density metric for comparisons between sites and reaches. All fish observed during the
snorkel surveys were classified by species and categorized into 20 mm length bins. To ensure
accuracy, snorkelers called out data, which was recorded by an individual on shore. Due to the
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cold water temperatures in April and May (0.5° C in April, and 4.0° C in May), all snorkeling
occurred at night since juvenile fish were not active during daylight hours.
Minnow trapping was conducted monthly from April through October. Minnow trap locations
throughout the study period were representative of habitats available to rearing salmonids. In
some cases, suitable habitat could not be sampled simply due to access (Reach 5). However,
during the course of the study, a total of 330 minnow traps were deployed within Grant Creek.
Minnow traps were constructed with 6.4 mm galvanized square wire mesh, and were
approximately 40.6 cm long, 22.9 cm wide, with a 2.2 cm entrance at each end of the trap. At
the time of deployment, a 16.4 cubic centimeter mass of cured and sterilized salmon eggs was
placed in a PVC tube approximately 2.5 cm in diameter and approximately 7.6 cm long, with
bait mesh stretched over each end and secured with rubber bands as an attractant. In addition to
the bait tube, a river rock was placed into the trap to help weigh it down. The trap was then
placed into the desired location parallel to flow, and was secured to shore with a length of
parachute cord.
At the time of deployment, characteristics of the site were recorded, which included:
• The minnow trap number (every minnow trap set had a unique and sequential
number);
• Habitat type (e.g., turbulent fast water riffle);
• General position within the channel (i.e., right bank, center, or left bank);
• Presence of large or small woody debris, overhead vegetation, or if there was an
undercut bank;
• The time the trap was set; and
• The unique GPS waypoint.
Traps typically fished 24 hours before they were processed. At the time of processing, fish were
placed into an 18.9-liter bucket for transport from the minnow trap site to the processing station.
Fish were placed into a solution of water and clove oil (6 drops per 3.8 liters of water). Once
anesthetized, fish were identified to species, and were measured (nearest millimeter) and
weighed (to the nearest tenth of a gram). Fish were then placed into a 18.9-liter bucket of fresh
water and allowed to recover before being released in the general area of capture.
A fixed-site telemetry station and mobile telemetry surveys were used to assess the use of Reach
5 by adult resident fish. As discussed previously, a total of 20 adult rainbow trout and 1 Dolly
Varden were surgically implanted with digitally encoded transmitters. Telemetry surveys
occurred twice per week, and were conducted as far upstream into Reach 5 along the left bank as
possible. Additional surveys were conducted from the canyon rim from the right bank as
necessary. If a tagged fish was detected within Reach 5, it was tracked until its position could be
determined using triangulation techniques. In addition to mobile surveys, a fixed-antenna system
was installed.
The fixed-antenna system consisted of two underwater antenna arrays, the downstream array at
the Reach 4/5 break and the other array approximately 25 meters upstream. Underwater
telemetry systems were used in lieu of aerial systems to minimize the likelihood of signal bounce
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due to the canyon walls, and to reduce the detection range so that fish entry into Reach 5 could
be determined. Each array consisted of 4 bared coaxial antennas that were evenly spaced along a
steel cable, which was secured to each shoreline and weighted down so that the antennas were on
the bottom of Grant Creek. The four antennas were combined with a 4-way combiner, which
was then amplified and the signal transmitted via coaxial cable to a Lotek SRX/DSP receiving
system. Each antenna array was attenuated so as to balance the system to provide equal signal
reception with the transmitter an equidistant from each antenna array (Evans and Stevenson
2012). Each antenna array was monitored independent of the other, so that it was possible to
determine when a tagged fish moved upstream into Reach 5, the direction of travel, and when a
tagged fish migrated downstream of Reach 5. Each antenna array had a detection range of
approximately 15 meters.
4.2.3 Resident and Rearing Fish Use of Open Water Habitats in Lower Grant
Creek
Assessment of use by resident and rearing fish in lower Grant Creek was accomplished with the
same suite of techniques as in Reach 5. That is, radio telemetry was used to determine
movement and feeding habitat of adult rainbow trout; and juvenile use was assessed using an
incline plane trap, minnow trapping, and snorkeling. In addition, beach seining was also used to
assess juvenile resident and rearing fish use of Reaches 1-4.
To identify potential feeding and spawning habitat of adult rainbow trout, methods were
employed as discussed above. That is, mobile surveys were conducted twice per week, and all
locations were determined using triangulation techniques, which were recorded on maps.
The incline plane trap was located within a scour pool immediately upstream of the Reach 1/2
break. The purpose of this trap was to intercept juvenile salmonids migrating downstream within
Grant Creek. The intent of deploying two traps; one at the bottom of Reach 5, and the other as
close as possible to the Grant Creek confluence was to estimate relative abundance within Reach
5, and the Reach 1-4 sections of Grant Creek separately. As discussed, it was not possible to fish
the upper trap for the better portion of the study period, so it was not possible to determine
juvenile use of Reaches 1-4 exclusively. However, the continuous operation of the lower trap
did allow abundance above that trap (including Reach 5) to be estimated. To do so, it was
necessary to conduct efficiency trials of the lower trap. To estimate efficiency, captured
juveniles were marked using a Bismark Brown dye solution (0.4 gm/18.9 liters of water) for 30
minutes, and then released upstream of the trap. Recapture rates were then calculated for each
species of juveniles. Operation of the incline plane trap was conducted 24 hours per day, seven
days per week. The exception to this protocol was when either high flows or debris load made
operations either ineffective or too dangerous to operate the trap.
To estimate abundance within Reaches 1-5, we used a season-wide estimator that accounts for
trap efficiency, data gaps due to trap outages, and provides estimates of standard error. The
season-wide estimator of total juvenile abundance ()*N is the sum of estimated abundance when
the index counts at the incline plane trap are present ()N% and during periods when such data are
missing ()ˆjN , i.e.,
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*
1
ˆk
j
j
N N N
=
=+∑%
Where:
k = number of missing trap index count events during the season.
A detailed description of the calculations used to estimate juvenile abundance is presented in
Appendix 1 (Skalski and Townsend 2014).
Scatter plots and line graphs were used to describe the size and time of emigration for juvenile
salmonids captured in the lower incline plane trap on Grant Creek. Fork length (mm) and weight
(0.2 grams resolution) of nearly all juvenile fish were taken to document the size of downstream
migrants. The date of capture documented the time of emigration and helped to identify periods
of downstream migration and movement. The size and time of emigration provided some insight
into the basic life history of juvenile fish in Grant Creek.
Minnow trapping and snorkeling were conducted as described in Section 4.2.2, and will therefore
not be discussed here. Beach seining was also employed within several sites in Reaches 1-4.
However, due to the large and irregular substrate, seining was only partially effective and was
abandoned as a means to sample juvenile fish in Grant Creek. Numbers of fish captured with
beach seining are not reported for Grant Creek because of limited success. Beach seining was
successfully used in the Trail Lake Narrows in areas of smaller substrate.
4.3 Trail Lake Narrows Fish and Aquatic Habitats
The Trail Lake Narrows was sampled to determine species diversity and relative abundance.
The Narrows was sampled from the downstream margin of the Grant Creek confluence to the
downstream margin of the island immediately below the Narrows, and included both channels on
each side of the island. Angling was the only means of assessing adult salmonid (rainbow and
Dolly Varden) presence, and was conducted during a single day in July. A total of seven angling
stations were used and were selected to represent the area of potential impact associated with the
installation and use of an access road into the Study Area. On July 17, 2013, two personnel
fished each angling station for 30 minutes, and recorded both fish captured, and fish that were
hooked but not landed. Captured fish were identified as to species, and length (mm) and weight
(grams to the nearest tenth of a gram) were recorded. For fish that were hooked but not landed,
species and an estimate of length were noted when possible.
To assess juvenile presence and relative abundance, minnow trapping and beach seining were
used in the Trail Lake Narrows area. Snorkeling was not possible because of high turbidity (i.e.,
poor visibility). Over the course of a week, a total of 52 minnow traps were deployed (13 set
locations with a total of 4 traps per set). As with all minnow trapping efforts, traps fished for
about 24 hours, and a description of the location was recorded. Beach seining occurred the night
of July 23 and a total of three sites were seined. Three seines were composited at each location
and typically occurred where fine gravel and sand were present. Beach seining was based on the
methodology described in Hahn et al. (2007). A 15.2-m long, 0.6-cm mesh beach seine with a
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bottom lead line and an upper cork line was used. One crew member would wade into the water
at the selected site with the net attached to a 1.5-m pole, all the time keeping the bottom of the
net on the stream bottom. The second individual would unspool netting from the stream edge
from a second 1.5-m pole in order to keep it somewhat taught as the first individual encompassed
the desired area. Once the sample area had been enclosed, both individuals moved towards each
other along the stream margin trapping fish within the seine. Fish from minnow traps and beach
seines were transferred to an 18.9-L bucket where they anesthetized in a clove oil solution (6
drops per 3.8 L of water). Fish were enumerated by species, measured (to the nearest
millimeter), weighed (to the nearest tenth of a gram) and then allowed to recover in a bucket of
fresh water. Once equilibrium was achieved, fish were released back into the general area of
capture.
5 RESULTS
In the sections that follow, the results of field collection efforts accomplished on Grant Creek in
2013 are presented.
5.1 Grant Creek Salmon Spawning Distribution and Abundance
To assess the abundance and distribution of spawning salmon, fish were enumerated at the weir
to estimate spawning escapement, while redd surveys and radio telemetry surveys documented
the distribution of spawning.
5.1.1 Salmon Escapement to Grant Creek – Relative Species Abundance
As discussed in Section 4.1.1, a weir was placed in Reach 1 of Grant Creek to intercept, count
and sample adult salmonids migrating upstream. Daily fish counts were used to estimate run
timing and provided an overall estimate of escapement to Grant Creek. Some fish intercepted at
the weir were sampled to obtain estimates of age structure, length, weight, and to secure genetics
samples for the ADF&G. The weir also allowed researchers to Floy tag and radio tag adult
salmonids. Genetic samples were delivered to ADF&G but those analyses will not be presented
in this report.
5.1.1.1 Weir Count
There were 1,439 salmon that passed upstream of the weir on Grant Creek while 52 of those
salmon passed back downstream of the weir for a net passage of 1,387 salmon (Table 5.1-1).
Sockeye salmon were the dominant run of salmon entering Grant Creek with 1,117 counted
above the weir. There were 10 pink, 23 Chinook and 237 coho salmon counted above the weir.
The net passage of salmon across the weir does not include salmon that entered and potentially
spawned in Grant Creek downstream from the weir.
In the next section, total spawning escapement was assessed using area-under-the-curve
methodology to provide total spawning escapement to Grant Creek in 2013.
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Table 5.1-1. Upstream, downstream and net passage of pink, Chinook, sockeye and coho salmon across
the weir in Grant Creek, 2013.
Species Upstream Passage Downstream Passage Net Passage
Pink Salmon 12 2 10
Chinook Salmon 35 12 23
Sockeye Salmon 1,153 36 1,117
Coho Salmon 239 2 237
Total 1,439 52 1,387
5.1.1.2 Escapement Estimate: Area under the curve (AUC)
Several different surveys (i.e., visual, telemetry and carcass) were performed on Grant Creek to
estimate escapement with the area under the curve methodology (Bue 1998). The information
documents estimates for stream life, observer efficiency, and escapement for 2013 and 2009
(recalibrated count).
5.1.1.2.1 Stream Life
Stream life was estimated as the mean of the pooled recovery of Floy tagged and radio tagged
salmon in Grant Creek. The pooled information was used because radio tags alone did not
adequately cover the entire passage distribution of fish across the weir. Tag schedules for the
salmon migration to Grant Creek were based on visual surveys conducted in 2009 for Chinook
and sockeye. In 2009, the peak visual counts for Chinook and sockeye occurred the third week of
August and second week of September, respectively. Peak counts of Chinook and sockeye
occurred 1-2 weeks earlier in 2013. There was little information on the run timing of coho
salmon. The pooled data provided a better estimate of stream life particularly for fish earlier in
the run for sockeye and later in the run for coho salmon.
Stream life estimates are provided for pooled data, radio tags only and Floy tags only. Mean
stream life for the pooled data for Chinook, sockeye and coho salmon was 11 days, 14 days and
16 days, respectively (Table 5.1-2). Stream life was different for the two tags employed, but the
mean stream life from radio tags was consistently 4-6 days less than that estimated from Floy
tags.
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Table 5.1-2. Stream life estimates for the combined recovery of Floy tagged and radio tagged Chinook,
sockeye and coho salmon in Grant Creek, 2013.
Species
Percent
Recovered
Stream Life
Tagged Recovered Mean SD Min Max
Combined Recovery
Chinook 33 14 42 11 6.2 4 22
Sockeye 533 195 37 14 5.9 2 30
Coho 176 77 44 16 5.9 1 37
Radio Tags Only
Chinook 9 7 78 8 3.9 4 14
Sockeye 65 40 62 9 2.6 2 15
Coho 50 32 64 14 4.6 1 22
Floy Tags Only
Chinook 33 7 21 13 7.5 4 22
Sockeye 533 155 33 15 5.8 4 30
Coho 176 45 26 18 6.3 8 37
5.1.1.2.2 Observer Efficiency
Observer efficiency was estimated from the relationship of visual survey counts to weir counts
on Grant Creek. Because salmon die periodically throughout the spawning season, an adjustment
was made to the cumulative weir count to adjust for mortality. The mean stream life estimated
from salmon in Grant Creek was applied to the cumulative count to account for mortality. The
count was also adjusted to correct for fish passage on the date and time of the visual survey.
By way of example, on August 29 the cumulative weir count for sockeye salmon passed the weir
was 720 fish (Table 5.1-3). To adjust the cumulative weir count on that date for stream life, we
subtracted the cumulative weir count of sockeye that had passed the weir 14 days prior (August
15). The cumulative count of sockeye 14 days prior was 15 fish. The adjusted count was 705
fish (720-15=705). The weir count was also adjusted by 99 fish on the date of the visual survey
because those fish had not passed the weir by the time the visual survey was conducted. The
final adjusted weir count equaled 606 sockeye (705-99=606). During the visual survey on
August 29, 442 sockeye were observed above the weir on Grant Creek. Therefore, the observer
efficiency for the August 29 visual survey for sockeye was 72.9 percent (442/606).
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Table 5.1-3. Cumulative weir counts for sockeye adjusted for a stream life of 14 days and for fish passage
at the weir on dates of visual surveys.
Date
Cumulative
Weir Count
Adjusted for
Stream Life (14
days)
Fish passage
adjusted for
time of day
Adjusted Weir
Count Visual Counts
8/2/2013 0 0 0 0 0
8/9/2013 8 0 0 8 2
8/16/2013 15 5 4 6 3
8/23/2013 169 8 35 126 85
8/29/2013 720 15 99 606 442
9/6/2013 1,021 244 13 764 543
9/16/2013 1,115 933 1 181 211
9/21/2013 1,115 1,061 0 54 52
9/28/2013 1,115 1,111 0 4 2
10/4/2013 1,116 1,115 0 1 0
10/10/2013 1,117 1,115 0 3 1
During visual surveys, observers typically underestimated the number of live salmon in Grant
Creek. The plots of visual counts to adjusted weir counts revealed strong linear relationships for
salmon in Grant Creek (Figure 5.1-1). Observer efficiency (slope of the line) was 0.60 for
Chinook, 0.72 for sockeye, and 0.75 for coho. The trend in observer efficiency for salmon in
Grant Creek fit our general expectations. For Chinook, we expected the lowest observer
efficiency because they remained in deeper, faster waters during higher flows making them the
most difficult to observe. In general, sockeye remained near the stream banks in shallower water
making them easier to see than Chinook. For coho salmon, observations during stream surveys
were more favorable because of reduced flow and better water clarity.
Stream life and observer efficiency estimates for salmon in Grant Creek were used to estimate
total escapement to Grant Creek and as a comparison to the weir count. Stream life and observer
efficiency estimates were also applied to calculations of area-under-the-curve estimates for
Chinook and sockeye provided in the 2009 escapement (HDR 2009b). In the 2009 escapement
estimates, outside literature sources and professional judgment were used to estimate both stream
life and observer efficiency. No escapement estimates for coho in Grant Creek were provided in
2009.
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Figure 5.1-1. Observer efficiency relationships for sockeye, Chinook and coho salmon in Grant Creek,
2013.
y = 0.72x + 7.1642
R² = 0.9836
0
200
400
600
800
0 200 400 600 800Visual CountAdjusted Weir Count
Grant Creek
Relationship between visual counts
and adjusted weir counts
Sockeye Salmon
y = 0.5968x - 0.4317
R² = 0.935
0
5
10
15
0 5 10 15Visual CountAdjusted Weir Count
Chinook Salmon
y = 0.7478x - 6.0237
R² = 0.8884
0
25
50
75
100
125
150
0 25 50 75 100 125 150Visual CountAdjusted Weir Count
Coho Salmon
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5.1.1.2.3 Estimated Escapement: AUC
In this section, two escapement estimates are provided for Grant Creek based on visual counts.
The first estimate is the estimated escapement above the weir and the second estimate is for the
entire stream. Visual counts were conducted from the beginning of August until the end of the
first week of November (Table 5.1-4; Figures 5.1-2, 5.1-3 and 5.1-4). Visual counts were
separated as “below weir” and “above weir” during each survey to make direct comparisons to
the total escapement above the weir. Plots of area-under-the-curve estimated for Chinook,
sockeye and coho salmon are presented in Figure 5.1-5.
Peak visual counts (above the weir) for Chinook, sockeye and coho salmon occurred on August
28, September 6 and October 10, 2013, respectively. It should also be noted that three coho were
observed on the last visual survey on November 7. It was assumed that by the next week no
coho would be observed in Grant Creek and if there were any remaining fish it would have a
minor effect on AUC estimates.
Table 5.1-4. Visual counts of sockeye, Chinook and coho salmon above and below the weir in Grant
Creek, 2013.
Date Day of Year
Sockeye Chinook Coho
Below
Weir
Above
Weir
Below
Weir
Above
Weir
Below
Weir
Above
Weir
8/2/2013 214 0 0 0 0 0 0
8/9/2013 221 0 2 0 0 0 0
8/16/2013 228 8 3 14 1 0 0
8/23/2013 235 43 85 22 6 0 0
8/29/2013 241 59 442 19 11 0 0
9/6/2013 249 45 543 2 4 0 0
9/16/2013 259 12 211 0 0 0 6
9/21/2013 264 10 52 0 0 0 10
9/28/2013 271 0 2 0 0 14 29
10/4/2013 277 0 0 0 0 7 71
10/10/2013 283 0 1 0 0 8 127
10/18/2013 291 0 0 0 0 4 88
10/24/2013 297 0 0 0 0 3 63
11/1/2013 305 0 0 0 0 2 12
11/7/2013 311 0 0 0 0 1 2
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Figure 5.1-5. Plots of visual counts used to estimate area-under-the-curve for Chinook, sockeye and coho
salmon in Grant Creek, 2013.
0
5
10
15
20
25
30
35
40
214 221 228 235 241 249 259 264 271 277 283 291 297 305 311Visual CountDay of the Year
Grant Creek
Chinook visual counts
Above weir (AUC=180)
Entire stream (AUC=590)
0
25
50
75
100
125
150
214 221 228 235 241 249 259 264 271 277 283 291 297 305 311Visual CountDay of the Year
Coho visual counts
Above weir (AUC=2,763)
Entire stream (AUC=3,021)
0
100
200
300
400
500
600
700
214 221 228 235 241 249 259 264 271 277 283 291 297 305 311Visual CountDay of the Year
Sockeye visual counts
Above weir (AUC=10,483)
Entire stream (AUC=11,787)
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Estimates of escapement above the weir based on visual counts (AUC) were within ±12 percent
of the weir counts (Table 5.1-5). Escapement estimates for the entire stream were 90 Chinook,
1,169 sockeye and 252 coho salmon.
Table 5.1-5. Escapement estimates for salmon in Grant Creek at the weir and estimated from area-under-
the curve with stream life and observer efficiency
Species
Stream
Life
(s)
Observer
Efficiency
(v)
Escapement
Estimates 2013
Escapement
Estimate 2009
Weir Count
Above Weir
(AUC)
Entire
Stream
(AUC) Estimate Adjusted
Pink --- --- 10 --- --- --- ---
Chinook 11 0.60 23 27 (112%) 90 (391%) 231 148
Sockeye 14 0.72 1,117 1,040 (93%) 1,169 (105%) 6,293 2,705
Coho 16 0.75 237 231 (97%) 252 (106%) --- ---
The area-under-the-curve estimates for sockeye and coho salmon for the entire stream add an
additional 52 sockeye and 15 coho salmon to the weir count. These additional fish downstream
from the weir fit within our expectation of the number of spawning fish for both sockeye and
coho salmon. However, the difference in the Chinook weir count (23 fish) and the estimate for
the entire stream (90 fish) implies that 67 additional Chinook spawned downstream of the weir.
That estimate appears to be too high because we did not observed that much more additional
spawning activity below the weir. Given the level of movement (downstream) for Chinook
across the weir, it is likely that the Chinook observed during visual counts downstream of the
weir may have spawned in the Trail Lake Narrows or elsewhere. That is, our visual surveys
counted fish that moved into lower Grant Creek but did not remain there to spawn, which
inflated the number of fish in Grant Creek downstream of the weir. We offer two arguments in
support of this conclusion:
1. There were 35 Chinook that crossed upstream of the weir and 12 fish migrated back
downstream. That equates to about 34 percent fallback rate. The percent of fallback
for sockeye (3 percent) and coho (<1 percent) was much lower.
2. There were three Chinook salmon redds observed downstream of the weir. There
were 3 redds counted above the weir with an escapement of 23 fish, which equates to
about 7.6 fish per redd above the weir. There were 67 additional fish estimated by
AUC downstream of the weir and only three redds.
A more realistic estimate of total escapement to Grant Creek for Chinook salmon is 46 fish (6
redds x 7.6 fish/redd = 46 fish).
In 2009, the estimated escapement using area under the curve methodology was 231 Chinook
and 6,293 sockeye salmon (HDR 2009b). Recalibrating those counts by stream life and observer
efficiency from 2013 adjusted those counts to 148 Chinook and 2,705 sockeye salmon (Table
5.1-5).
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5.1.2 Life History Characteristics
Adult salmon were counted and subsampled at the weir to describe life history characteristic of
the spawning population. The information documents the run timing, size and age structure of
returning salmon to Grant Creek.
5.1.2.1 Run Timing
Run timing for adult salmon to Grant Creek extended over a 13 week period beginning at the end
of July and finishing near the end of October. Chinook and pink salmon both entered Grant
Creek over a four week period (Table 5.1-6). Pink salmon passed the weir on Grant Creek from
the first week of August to the end of August. Chinook salmon passed the weir from the second
week of August through the first week of September. Peak passage for pink and Chinook salmon
occurred on week 32 and 33, respectively. The adult migration for sockeye occurred over a ten
week period beginning the last week of July with a peak at the end of August and the second
week of October. Two individual sockeye extended the run timing an additional three weeks
after the majority of the run was complete. Coho salmon began entering Grant Creek the second
week of September, peaked the first week of October and ended the last week of October when
the weir was removed (October 24).
Table 5.1-6. Run timing by week of the year for pink, Chinook, sockeye and coho salmon assessed at the
weir on Grant Creek, 2013.
Week of Year Dates Pink Chinook Sockeye Coho
31 Jul 28- Aug 03 0 0 5 0
32 Aug 04 - Aug 10 6 0 3 0
33 Aug 11- Aug 17 2 11 16 0
34 Aug 18 - Aug 24 1 3 220 0
35 Aug 25 - Aug 31 1 7 601 0
36 Sep 01 - Sep 07 0 2 201 0
37 Sep 08 - Sep 14 0 0 65 16
38 Sep 15 - Sep 21 0 0 4 17
39 Sep 22 - Sep 28 0 0 0 40
40 Sep 29 - Oct 05 0 0 1 96
41 Oct 06 - Oct 12 0 0 1 42
42 Oct 13 - Oct 19 0 0 0 21
43 Oct 20 - Oct 26 0 0 0 1
Total 10 23 1,117 237
5.1.2.2 Size (length and weight)
Length and weight measurements were collected at the weir to describe the size of returning
salmon to Grant Creek (Table 5.1-7). Female Chinook salmon were larger than males (mean
length and weight). Male and female sockeye were similar with males slightly heavier and
longer than females. For coho salmon, the size of males and females was similar. On average,
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male coho salmon tended to be heavier than females but females were on average longer than
males. For pink salmon, males tended to be longer and heavier than females.
Table 5.1-7. Mean, maximum, and minimum length and weight of Chinook, sockeye and coho salmon
measured at the weir on Grant Creek, 2013.
Species Sex
Length cm (mid-eye to fork) Weight (kg)
Mean SD Max Min Number Mean SD Max Min Number
Chinook F 88 5.8 98 81 6 10.4 2.6 14.5 7.6 6
M 71 13.7 104 38 27 5.9 3.8 16.4 0.6 27
Coho F 59 4.0 68 45 116 3.3 0.7 5.0 1.4 116
M 58 4.3 67 45 116 3.5 1.0 6.5 1.5 116
Sockeye F 54 3.5 60 42 415 2.6 0.5 3.8 1.0 415
M 55 4.6 77 33 361 3.0 0.7 4.9 0.5 360
Pink F 42 2.3 46 39 9 1.0 0.2 1.3 0.8 9
M 45 3.8 51 40 6 1.3 0.4 2.1 0.9 6
Note: Samples size for fish measured may include some fish that past upstream of the weir and subsequently
passed back downstream.
5.1.2.3 Age Structure
In this section, information is reported on the length-and-age-at-return and freshwater life history
for Chinook, coho and sockeye salmon. For Chinook and coho salmon, scale samples were
collected at the weir and for sockeye, otoliths were extracted from carcasses and used for age
determination. Length measurements were from mid-eye to fork of the caudal fin.
Chinook salmon returned to Grant Creek at 3 to 6 years of age with most (84 percent) returning
as 4 and 5-year old fish (Table 5.1-8). Three year old fish made up about 4 percent and 6-year
old fish made up about 3 percent of the fish sampled. The age structure of male and female
Chinook salmon differed slightly with one male returning at three years of age. Coho salmon
returned at three to five years of age with most (90 percent) returning as 4-year old fish. Three
year old fish made up about 4 percent and 5-year old fish made up about 7 percent of the fish
sampled. The age structure of male and female coho salmon was similar in age-at-return with
slightly more male fish returning at five years of age than females. Sockeye salmon returned at
four to six years of age with most (95 percent) returning as 5-year old fish. Female sockeye
returned as 4 and 5 year old fish. Males returned as 4, 5 and 6-year old fish.
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Table 5.1-8. Age-at-return for coho, Chinook and sockeye salmon sampled in Grant Creek, 2013.
Sex
Total Age
Total
Age-3 Age-4 Age-5 Age-6
No. Percent No. Percent No. Percent No. Percent
Chinook Salmon
Female 0 0.0 0 0.0 4 80.0 1 20.0 5
Male 1 5.0 12 60.0 5 25.0 2 10.0 20
Total 1 4.0 12 48.0 9 36.0 3 12.0 25
Coho Salmon
Female 3 3.5 78 91.8 4 4.7 0 0.0 85
Male 3 3.6 73 88.0 7 8.4 0 0.0 83
Total 6 3.6 151 89.9 11 6.5 0 0.0 168
Sockeye Salmon
Female 0 0.0 3 5.9 48 94.1 0 0.0 51
Male 0 0.0 0 0.0 47 95.9 2 4.1 49
Total 0 0.0 3 3.0 95 95.0 2 2.0 100
In general, mean length increased with age for returning salmon to Grant Creek. Mean length
increased the most for Chinook between 3 and 4-year old fish (Table 5.1-9). For Chinook
salmon, females were larger than males at 5-year old fish but as 6-year old fish. Female coho
salmon were slightly larger than males as 4-year old fish, smaller as 3-year old fish and the same
as 5-year old fish. Like Chinook, mean length increased the most for coho between 3 and 4-year
old fish. For sockeye salmon, males tended to be larger than females and the largest increase in
mean size was between 4 and 5-year old fish.
Table 5.1-9. Length-at-age for returning coho salmon sampled at the Grant Creek weir in 2013. Length
(cm) was measured from mid-eye to the fork of the caudal fin.
Sex
Age-3 Age-4 Age-5 Age-6
No.
Mean Length
(cm) No.
Mean Length
(cm) No.
Mean Length
(cm) No.
Mean Length
(cm)
Chinook Salmon
Female 0 --- 0 --- 4 86.0 1 97.5
Male 1 37.5 12 65.1 5 77.0 2 100.3
Total 1 37.5 12 65.1 9 81.0 3 99.4
Coho Salmon
Female 3 52.1 78 59.0 4 60.3 0 ---
Male 3 60.6 73 58.4 7 60.3 0 ---
Total 6 56.4 151 58.7 11 60.3 0 ---
Sockeye Salmon
Female 0 --- 3 48.6 48 56.1 0 ---
Male 0 --- 0 --- 47 57.1 2 58.1
Total 0 --- 3 48.6 95 56.6 2 58.1
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The European method of age designation documents the general freshwater life history for adult
salmon returning to Grant Creek. For Chinook, all fish spent 1 winter (1.x) in freshwater before
migrating to the ocean (Table 5.1-10). The amount of time that coho spent in freshwater varied
the most of returning salmon. Most (88 percent) coho salmon spent two winters (2.x) in
freshwater while about 2 percent migrated to the ocean in their first year of life (0.x). Coho
salmon that had spent one winter in freshwater (1.x) made up 4 percent and fish that spent 3
winters (3.x) in freshwater made up about 6 percent. Most (97 percent) adult sockeye returning
to Grant Creek spent one year in freshwater (1.x) before migrating to the ocean. A few (3
percent) sockeye remained in freshwater for two years (2.x) before they migrated to the ocean.
Table 5.1-10. General freshwater life history of Chinook, coho and sockeye salmon returning to Grant
Creek, 2013.
Species
0.x 1.x 2.x 3.x
Total No. Percent No. Percent No. Percent No. Percent
Chinook 0 0 25 100 0 0 0 0 25
Coho 3 2 7 4 148 88 10 6 168
Sockeye 0 0 97 97 3 3 0 0 100
Notes:
European Age Designation
0.x = Juvenile fish migrated to the ocean in its first year of life (no freshwater annulus).
1.x = Juvenile fish migrated to the ocean in its second year of life (one winter in freshwater).
2.x = Juvenile fish migrated to the ocean in its third year of life (two winters in freshwater).
3.x = Juvenile fish migrated to the ocean in its fourth year of life (three winters in freshwater).
5.1.2.4 Egg Voidance
Female carcasses were examined to describe spawner success (egg retention). Table 5.1-11
presents the number of carcasses recovered, mean egg retention and the number of females
assessed.
Table 5.1-11. Number of Chinook, sockeye, pink, and coho salmon recovered during carcass surveys on
Grant Creek, 2013.
Species Females Males
Total
Recovered
Mean Egg
Retention
Number Females
Assessed
Chinook 5 10 15 255 5
Coho 28 35 63 289 28
Pink 8 3 11 100 2
Sockeye 266 218 484 81 257
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5.1.3 Distribution of Spawning Salmon in Grant Creek
The distribution of spawning salmon in Grant Creek was investigated by conducting redd
surveys and mobile telemetry surveys. Redd surveys were conducted at least once a week during
the spawning period to document the location, number, and time of redd construction in Grant
Creek. Documenting the number of redds in Grant Creek was at times hampered by stream flow,
turbidity and mass spawning. Mobile surveys documented the locations of tagged fish during the
course of the spawning period, which aided in documenting important spawning locations and
resting pools. Both surveys were used together to help identify sensitive time periods and
habitats for salmon reproduction.
The following pages document the locations where redds were observed and where radio tagged
salmon were documented.
Pink, Chinook, sockeye and coho salmon spawned in Grant Creek during the summer and fall of
2013 (Figures 5.1-6 through 5.1-9). The number of new redds observed during each week of the
study period was documented by week of the year (1-52). As expected, the distribution of redds
closely follows the distribution of visual detections (Figures 5.1-2 through 5.1-4) and mobile
telemetry surveys (Figures 5.1-10 through 5.1-12).
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5.1.3.1 Time of Spawning
Salmon began building redds the first week of August and ended spawning activity at the end of
October (Table 5.1-12). Pink salmon began spawning in early August with only two redds
constructed near the weir in Reach 1. Chinook salmon began spawning in mid-August and built
six redds in a three week period. Sockeye began spawning at the end of August building 308
redds within the first two weeks. By the third week (week 37) new redds and old redds could not
be distinguished in the mass spawning aggregates. Spawning activity (active digging) was
observed until the last week of September. Coho began spawning the first week of October and
were complete at the end of the month constructing 72 redds in Grant Creek.
Table 5.1-12. Number of new redds constructed in Grant Creek by week of the year for pink, Chinook,
sockeye and coho salmon in 2013. A designation of “MS” (Mass Spawning) means that new redds and
old redds for could not be distinguished in the mass spawning aggregates.
Week Dates
Species
Total Pink Chinook Sockeye Coho
31 Jul 28 - Aug 03 0 0 0 0 0
32 Aug 04 - Aug 10 2 0 0 0 2
33 Aug 11 - Aug 17 0 0 0 0 0
34 Aug 18 - Aug 24 0 1 0 0 1
35 Aug 25 - Aug 31 0 3 200 0 203
36 Sep 01 - Sep 07 0 2 108 0 110
37 Sep 08 - Sep 14 0 0 MS 0 0
38 Sep 15 - Sep 21 0 0 MS 0 0
39 Sep 22 - Sep 28 0 0 MS 0 0
40 Sep 29 - Oct 05 0 0 0 5 5
41 Oct 06 - Oct 12 0 0 0 47 47
42 Oct 13 - Oct 19 0 0 0 13 13
43 Oct 20 - Oct 26 0 0 0 6 6
44 Oct 27 - Nov 02 0 0 0 1 1
45 Nov 03 - Nov 09 0 0 0 0 0
Total 2 6 308 72 388
5.1.3.2 Spawning Distribution
The distribution of spawning salmon in Grant Creek was document with both redd surveys and
mobile telemetry surveys. The distribution of salmon redds was concentrated (95 percent) within
Reaches 1-3 of Grant Creek (Table 5.1-13). Sockeye and coho salmon spawned in every reach
of Grant Creek while Chinook only spawned in Reach 1, 3 and 4. The spawning locations of
sockeye and coho salmon often overlapped in several locations in reaches 1 and 3. Pink salmon
only spawned in Reach 1. There was less spawning in Reach 2 (15 percent), Reach 4 (4 percent)
and Reach 5 (1 percent). Spawning only occurred in a few locations in Reaches 4 and 5.
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Table 5.1-13. Number and proportion of redds counted in each reach of Grant Creek for pink, Chinook,
sockeye and coho salmon in 2013.
Reach
Species
Total Proportion Pink Chinook Sockeye Coho
1 2 4 144 18 168 0.433
2 0 0 52 7 59 0.152
3 0 1 102 38 141 0.363
4 0 1 7 7 15 0.039
5 0 0 3 2 5 0.013
Total 2 6 308 72 388 1.000
Radio telemetry tracking occurred throughout the spawning period for Chinook, sockeye and
coho salmon. Radio tracking was used to determine the distribution of salmon within Grant
Creek (Figures 5.1-10 through 5.1-12). Those distributions likely include migration (wandering),
spawning and resting (pools) behaviors within Grant Creek.
Of the nine Chinook that were radio-tagged, seven were detected within Reach 1, three within
Reach 2, none in reaches 3 and 4, and five within Reach 5 (Table 5.1-14). While five Chinook
were detected within Reach 5, no redds were associated with these detections nor were any
Chinook redds observed in Reach 5. In reaches 3 and 4 there were no unique fish detections but
at least two redds were observed in those reaches. In Reach 2 there were 3 fish detected but no
redds were observed in that reach. In Reach 1 there were 7 fish detected and 4 redds observed.
Table 5.1-14. The number of unique detections of radio-tagged adult salmon by species and reach within
Grant Creek.
Reach Chinook (n = 9) Sockeye (n = 65) Coho (n = 50) Total Proportion
1 7 48 40 95 0.41
2 3 14 12 29 0.13
3 0 18 30 48 0.21
4 0 3 6 9 0.04
5 5 20 26 51 0.22
Total 15 103 114 232 1.00
Unique detections by reach for sockeye more closely resemble observed redds by reach as
presented in Table 5.1-13. Of the 65 radio-tagged sockeye, 48 were detected in Reach 1, 14 in
Reach 2, 18 in Reach 3, 3 in Reach 4, and 20 in Reach 5 (Table 5.1-14). There were 20 sockeye
detected in Reach 5 and at least 3 redds were observed. In reach 3 there were 18 sockeye
detected and 102 redds were observed. In Reach 2 there were 14 fish detected and 52 redds
observed. Reach 1 had 48 fish detected and there were 144 redds observed in this reach.
Of the 50 coho salmon radio-tagged, 40, 12, 30, 6, and 26 tagged fish were observed in reaches
1-5, respectively (Table 5.1-14). Coho were detected in all reaches of Grant Creek and indeed
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spawned in all reaches of Grant Creek like sockeye salmon. The majority of coho salmon were
detected in Reaches 1 and 3 and these were the areas where most of the spawning occurred.
Clearly, detection of radio tagged fish helped describe the distribution of salmon entering Grant
Creek, but it did not always indicate that spawning occurred. However, most fish appeared to be
closely associated with either spawning areas or resting pools. The proportion of redds observed
in Grant Creek was similar to the proportion of fish detected within each reaches. Reach 5 was
the most notable divergence with several fish detected in the lower portion of reach 5 but few
redds identified in this reach. The number of radio tagged detections in that reach may indicate
exploratory behavior and/or the inability to detect redds in the lower section of reach 5.
5.1.3.3 Spawning Habitat
In Grant Creek, most redds were located in the mainstem areas, but also occurred in side
channels and backwater areas (Table 5.1-15). Sockeye and coho both spawned in mainstem, side
channel and backwater areas while pink and Chinook only spawned in mainstem areas. In
mainstem areas, spawning usually occurred along the stream margins or in areas protected from
the main current. Chinook were the exception, building redds mid-channel within the stronger
current. In side channels, salmon spawned throughout the width of the channel and in backwater
areas, salmon usually selected locations close to the mainstem where suitable stream velocity and
substrate were present.
Table 5.1-15. Location of salmon redds within different channel areas of Grant Creek.
Species Backwater Areas Mainstem Areas Side Channel Areas Total
Chinook 0 6 0 6
Coho 4 49 19 72
Pink 0 2 0 2
Sockeye 27 239 42 308
Total 31 296 61 388
The majority of redds in Grant Creek were located in riffle (71 percent) and pool (19 percent)
habitat (Table 5.1-16). In Reach 1, spawning for pink, sockeye and coho salmon most often
occurred in riffle and pool habitat along the stream margins in the mainstem areas away from the
thalweg and the highest stream velocities. Chinook spawned only in riffle habitat most often
mid-channel where higher velocity and larger spawning substrates occurred. In Reach 2, most
spawning occurred in mainstem riffle habitat along the stream margins for sockeye and coho
salmon. Irregularities along the stream margin (large woody debris [LWD], bedrock, boulders)
of riffle habitat created areas of lower velocity and suitable spawning substrate. Sockeye and
coho also spawned in the stream margins of some pool habitat (lateral scour pool) of Reach 2. In
Reach 3, most spawning occurred in pool habitat in mainstem (scour pools) and side channel
areas (dammed pools). One large backwater area (pool habitat) was also used by sockeye and
coho salmon. In Reach 4, spawning occurred in mostly riffle habitat along the stream margins of
the right bank. Spawning also occurred along the left bank in pocket water (riffles w/ pockets)
formed by velocity breaks such as boulders or tree roots that allowed spawning gravels to
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accumulate. In Reach 5, spawning occurred in step pool habitat along the stream margins often
behind large boulders or bedrock outcroppings (velocity breaks) where gravels and cobbles
accumulated.
Table 5.1-16. Location of pink, Chinook, sockeye and coho salmon redds within reaches and aquatic
habitats of Grant Creek. A designation of “NA” means that the habitat type was not available in that reach
of Grant Creek.
Species Reach - Area Riffle Pool
Back
-water
Step
Pool Glide
Pocket
Water Total
Pink
1 - Mainstem 2 2
2 - Mainstem
3 - Mainstem
3 - Predominate Side Channel
3 - Secondary Side Channel
4 - Mainstem
5 - Mainstem
Chinook
1 - Mainstem 4 4
2 - Mainstem
3 - Mainstem 1 1
3 - Predominate Side Channel
3 - Secondary Side Channel
4 - Mainstem 1 1
5 - Mainstem
Sockeye
1 - Mainstem 129 15 144
2 - Mainstem 47 4 1 52
3 - Mainstem 18 19 23 60
3 - Predominate Side Channel 27 11 1 39
3 - Secondary Side Channel 3 3
4 - Mainstem 6 1 7
5 - Mainstem 3 3
Coho
1 - Mainstem 15 3 18
2 - Mainstem 6 1 7
3 - Mainstem 6 10 3 19
3 - Predominate Side Channel 7 8 15
3 - Secondary Side Channel 1 3 4
4 - Mainstem 5 2 7
5 - Mainstem 2 2
Total: 275 75 31 5 2 0 388
Proportion: 0.71 0.19 0.08 0.01 0.01 0.00 1.00
The majority of radio tagged salmon were detected in riffle (62 percent) and pool (24 percent)
habitat (Table 5.1-17). The proportion of detections in aquatic habitats of Grant Creek follows
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the distribution of redds. The slightly higher detection rate of fish in pools may be a related to
staging and resting behavior as well as spawning. Backwater areas along the mainstem also
appeared to be important spawning areas. In general, close inspection of maps that depict redd
locations and detections of tagged fish show a cluster of activity in mainstem riffle areas near
pool habitat.
Table 5.1-17. Number of detections for radio tagged Chinook, sockeye, and coho salmon in aquatic
habitats of Grant Creek, 2013.
Species Reach Riffle Pool
Back-
water
Step
Pool Glide
Pocket
Water Total
Chinook
1 - Mainstem 10 10
2 - Mainstem 6 2 2 10
3 - Mainstem 2 1 3
3 - Predominate Side Channel 0
3 - Secondary Side Channel 0
4 - Mainstem 0
5 - Mainstem 1 1
Sockeye
1 - Mainstem 49 2 51
2 - Mainstem 6 4 7 17
3 - Mainstem 9 7 4 20
3 - Predominate Side Channel 4 4
3 - Secondary Side Channel 0
4 - Mainstem 3 3
5 - Mainstem 0
Coho
1 - Mainstem 57 1 58
2 - Mainstem 6 3 10 19
3 - Mainstem 12 27 7 46
3 - Predominate Side Channel 6 14 20
3 - Secondary Side Channel 1 1
4 - Mainstem 3 3 6
5 - Mainstem 2 4 6
Total: 171 67 31 5 1 0 275
Proportion: 0.62 0.24 0.11 0.02 <0.01 0.00 1.00
5.2 Grant Creek Resident and Rearing Fish Abundance and Distribution
5.2.1 Adult Rainbow Trout Abundance, Distribution, and Spawning in Grant
Creek
A weir was placed in Reach 1 of Grant Creek to intercept, count and sample adult salmonids
migrating upstream. Daily fish counts were used to estimate run timing and provided an overall
estimate of escapement to Grant Creek. Dolly Varden and rainbow trout were intercepted at the
weir to help facilitate radio tagging. Fish captured at the weir that were radio-tagged were also
Floy-tagged.
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The migration period for rainbow trout lasted 6 weeks from May 24 to June 29 and resulted in
the capture of 13 adult rainbow trout (Table 5.2-1). The abundance of adult rainbow trout in
Grant Creek based on weir counts may be biased low. This conclusion is based on the
observation of two radio tagged rainbow trout, which were released upstream of the weir in June
and were subsequently captured downstream from the weir in July while angling. Neither of
these fish were captured and released downstream of the weir. Later, both of these fish were
detected upstream of the weir; again without being captured at the weir.
Table 5.2-1. Weekly passage of rainbow trout and Dolly Varden across the weir in Grant Creek, 2013.
Week of the Year Dates Rainbow Trout Dolly Varden
21 May 19 - May 25 3 0
22 May 26 - Jun 01 1 0
23 Jun 02 - Jun 08 1 0
24 Jun 09 - Jun 15 1 0
25 Jun 16 - Jun 22 3 0
26 Jun 23 - Jun 29 4 0
27 Jun 30 - Jul 06 0 0
28 Jul 07 - Jul 13 0 0
29 Jul 14 - Jul 20 0 0
30 Jul 21 - Jul 27 0 0
31 Jul 28- Aug 03 0 0
32 Aug 04 - Aug 10 0 0
33 Aug 11- Aug 17 0 0
34 Aug 18 - Aug 24 0 1
35 Aug 25 - Aug 31 0 4
36 Sep 01 - Sep 07 0 6
37 Sep 08 - Sep 14 0 3
38 Sep 15 - Sep 21 0 0
39 Sep 22 - Sep 28 0 0
40 Sep 29 - Oct 05 0 0
41 Oct 06 - Oct 12 0 0
42 Oct 13 - Oct 19 0 0
43 Oct 20 - Oct 26 0 0
Total 13 14
The relatively low abundance of rainbow trout passing the weir might be attributed to the date
the weir was placed into Grant Creek. Some adult rainbow trout may have moved upstream into
Grant Creek before the weir was in place. Angling was initiated to help capture fish for radio
tagging. Within the first two weeks, 16 adult sized (>300 mm FL) rainbow trout were tagged.
Many of these fish were captured upstream of the weir. In July two observers in dry suits and
snorkel gear inspected the weir and found no obvious areas of entry from mid-channel to the left
bank. The right bank undercut could not be inspected and is suspected to have been large
enough to provide some supplementary passage to rainbow trout.
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The migration period for Dolly Varden lasted 4 weeks from August 18 to September 14, with the
capture of 14 Dolly Varden (Table 5.2-1). Only one Dolly Varden was large enough for tagging,
and which appeared to be in spawning condition. Angling efforts in Grant Creek proved
unsuccessful to capture adult Dolly Varden for tagging.
5.2.2 Resident and Rearing Fish Use of Reach 5
To monitor fish use of upper Grant Creek, adult rainbow trout were surgically implanted with
radio tags to monitor their movements and use of Reach 5. A total of 20 adult rainbow trout
were radio-tagged, and included a portion of the fish collected at the weir, and a number of fish
captured above the weir using angling techniques. Minnow traps and snorkel surveys were also
used to assess the relative abundance of juvenile fish in upper Grant Creek.
Of the 20 adult rainbow trout that were surgically implanted with radio-transmitters, three males
and one female were detected within Reach 5 subsequent to their release. All four were detected
by the underwater antenna arrays located at the Reach 4/5 break. Because there were two
antenna arrays located approximately 30 meters apart, and they were monitored individually, it
was possible to determine when the tagged fish approached the Reach 4/5 break, and when they
migrated past that point and into Reach 5. Likewise, it was possible to determine the direction of
travel, and when a tagged fish migrated downstream and out of Reach 5. Of the four radio-
tagged fish that entered Reach 5, two were also detected during mobile surveys of the “Canyon
Reach” (Reach 5), providing a more detailed assessment of their positions.
On average, it took 9.9 days after tagging and release for the four fish to migrate upstream
through Grant Creek and be detected by the antenna array located at the Reach 4/5 break (median
of 6.6 days; range of 2.0 to 24.4 days; Table 5.2-2). Three of the four fish made a single foray
into Reach 5, spending on average 0.27 days within Reach 5. The fourth fish, a male, made three
different forays into Reach 5; the first lasting 4.35 days, the second 0.72 days, and the last foray
lasting 0.75 days, each venture into Reach 5 being separated by about 6 hours.
Table 5.2-2. The travel time and length of residence of radio-tagged rainbow trout detected in Reach 5 of
Grant Creek.
Fish I.D.
(Channel/Code) Sex
Travel Time from
Release to Reach 4/5
Break (days)
Length of Time within
Reach 5 (days)
2/12 Female 6.12 0.80
2/19 Male 24.37 0.01
17/31 Male 2.00
4.35
0.72
0.75
17/46 Male 7.05 0.01
The tagged female (Fish I.D. 2/12) spent 0.80 days in Reach 5, and was detected at the time of a
mobile telemetry survey. During this survey, this fish migrated upstream to a point
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approximately 135 meters above the Reach 4/5 break (Figure 5.2-1). The location where this
fish was detected was further scrutinized at the time of the telemetry survey, and its position was
determined using a bared-coaxial underwater antenna, which allows accuracy on the order of 3
meters or less.
The radio-tagged male (Fish I.D. 17/31), which made multiple forays into Reach 5, spent the
most time in Reach 5, and migrated the farthest upstream of the Reach 4/5 break (about 250
meters; Figure 5.2-1). Its location was ascertained during a mobile survey where its position was
triangulated from the top of the canyon rim from the right bank. As such it was not possible to
collect any information as to the specific location (i.e., habitat type, substrate, etc.).
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Minnow trapping and snorkeling were used in upper Grant Creek (Reach 5 only) from April
through October to document species diversity, relative abundance, and distribution. Over the
course of the study, there were 57 individual minnow traps (effort=1,318 hours) placed in
different locations capturing 205 fish in upper Grant Creek (Table 5.2-3; Figure 5.2-2).
Snorkeling was only conducted in April and May when stream flows and water clarity allowed.
Three step pools were snorkeled in April and two were snorkeled in May identifying 16 fish in
upper Grant Creek.
Table 5.2-3. Number of minnow traps, total effort, and number of fish captured in Reach 5 of Grant
Creek from April through October 2013.
Upper Grant Creek Minnow Trapping
Reach Number of Traps
Total Effort
(days)
Total Effort
(hrs) Number of Fish
5 57 54.9 1,318 205
Dolly Varden and rainbow trout were the most numerous fish captured in minnow traps followed
by Chinook, sculpins sp. and coho (Table 5.2-4). Juvenile Dolly Varden comprised half of the
fish captured in minnow traps.
Table 5.2-4. Number, proportion and CPUE of fish caught in Reach 5 of Grant Creek with minnow traps
from April through October 2013.
Upper Grant Creek Minnow Trapping
Species Number Proportion CPUE (fish/hr)
Chinook 31 0.15 0.024
Coho 5 0.02 0.004
Dolly Varden 102 0.50 0.077
Rainbow Trout 48 0.23 0.036
Sculpin sp. 19 0.09 0.014
Grand Total 205 1.00 0.156
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The relative abundance of fish observed in Reach 5 of Grant Creek varied over time (Table 5.2-
5). Repeated minnow trap sampling from April through October in upper Grant Creek showed
that relative abundance was lowest in May and increased to September (Figure 5.2-3; Table 5.2-
5). In general, peak abundance (catch) occurred from June through October. CPUE for juvenile
Chinook increased from April to a peak in September and declined in October (Figure 5.2-3).
Juvenile Chinook varied in size from 68-118 mm FL. CPUE for juvenile coho salmon peaked in
September and fish ranged in size from 60-95 mm FL. For Dolly Varden, the greatest CPUE
occurred in August but was fairly stable during the summer (June-August). The size range of
Dolly Varden captured in upper Grant Creek varied from 71-151 mm FL. Catch of juvenile
rainbow trout peaked in September and October (Table 5.2-5). Rainbow trout captured in upper
Grant Creek varied from 54-143 mm FL. No fish were captured in the plunge pool downstream
from the anadromous fish barrier in September when peak catch rates were generally highest for
most other species (except Dolly Varden).
Table 5.2-5. Number of fish captured in minnow traps by month for upper Grant Creek from April
through October 2013.
Month
Number
Chinook Coho
Dolly
Varden
Rainbow
Trout Sculpin sp.
Three-spine
Stickleback Total
APR 2 0 1 5 0 0 8
MAY 1 0 1 4 0 0 6
JUN 0 0 18 1 0 0 19
JUL 1 0 23 3 1 0 28
AUG 1 1 20 4 3 0 29
SEP 18 4 17 16 5 0 60
OCT 8 0 22 15 10 0 55
Total 31 5 102 48 19 0 205
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Figure 5.2-3. Catch-per-unit-effort (CPUE) for juvenile Chinook, coho, Dolly Varden and rainbow trout
from minnow trapping in upper Grant Creek from April through October, 2013.
Night time snorkel surveys in April and May within Reach 5 of Grant Creek documented 7
rainbow trout in April and 9 rainbow trout in May. These fish were observed in step pool habitat
and varied in size from 60-280 mm FL.
The upper incline plane trap was installed within a scour pool, which was located immediately
downstream of the Reach 4/5 break. Trap installation was completed on April 28, and the trap
was permanently removed on October 16. The trap was operated 24 hours per day, seven days
per week with a number of exceptions. Due to few fish being captured, the trap was not operated
the first three weekends of the study (May 4 and 5; May 11 and 12; and May 18 and 19). As
Grant Creek flows increased, the trap became increasingly problematic to operate. In addition to
high debris loads, the water velocity entering the trap was approaching 1 meter per second, with
large rolling waves. This caused flow entering the trap to surge, making it difficult to optimize
the trap settings. Efforts were made to reposition the trap within the pool; however there was
little flexibility in adjustment within the pool due to boulders. Towards the end of May,
velocities had reached a point where it was difficult to access the trap, and the level of risk to
personnel had become unacceptable. Therefore, on May 30 the trap was taken out of operation,
and on June 1 the trap was moved to a position along the left bank and the trap was secured. It
wasn’t until September 19 that flow subsided to a point where the trap could be moved into
fishing position, and trapping operations re-initiated.
During the juvenile migration, problems associated with the lower incline plane trap located at
the Reach 1/2 break became apparent. Juvenile salmonid fry were being observed along flooded
areas of Grant Creek, yet none of these fry-sized fish were being observed in the incline plane
0.000
0.002
0.004
0.006
0.008
0.010
APR MAY JUN JUL AUG SEP OCTCPUE (fish/hr)Month
Upper Grant Creek
CPUE of Fish Captured
in Minnow Traps
CK CO DV RB
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trap live box. Through ad hoc investigations, it was determined that the mesh size on the live
box, as well as the incline plane of the trap was too large, which allowed juvenile fish to escape
the trap. Modifications were made to both the incline plane and the live box; since the upper
incline plane trap located at the Reach 4/5 break was constructed identically to the lower trap,
alterations were made to it as well.
As discussed in the Methods Section, a goal of the study was to estimate abundance of juvenile
fish within Grant Creek, and to partition that estimate into two sections; Reach 5, and Reaches 1-
4. An estimate of abundance at the lower incline plane trap would represent all of Grant Creek;
that is, from the trap upstream to the waterfall at the top of Reach 5. To partition that estimate
into the two sections, it is then necessary to get an estimate of abundance for just Reach 5.
Given that the upper incline plane trap was inoperable during much of the juvenile migration due
to high flows, the collection of adequate numbers of fish to estimate trap efficiency at the upper
trap was not possible. As such, results for the upper incline plane trap, which are presented
below only include actual counts of fish collected at the trap, and results for the lower incline
plane trap presented in Section 5.2.3 include abundance estimates that are for all of Grant Creek.
During the operation of the upper incline plane trap, a total of 172 fish were processed. Of those,
there were 8 Chinook, 1 coho, 7 Dolly Varden, 5 rainbow trout, 19 sculpin, and 132 sticklebacks.
Due to the low numbers of species of interest, no fish were marked to assess trap efficiency.
5.2.3 Resident and Rearing Fish Use of Open Water Habitats in Lower Grant
Creek
To monitor fish use of lower Grant Creek, adult rainbow trout were surgically implanted with
radio tags to monitor their movements. Minnow traps and snorkel surveys were also used to
assess the relative abundance of juvenile fish in upper Grant Creek.
During the period of May 24 to July 11, a total of 20 adult rainbow trout were surgically
implanted with radio-transmitters; one in May, six in June, and 13 in July (Table 5.2-6). Of
those 20 fish, 8 were female, 11 were male, and the sex of one other was undetermined. The age
of adult rainbow trout (>300 mm) varied from three to seven years old, which is similar to what
has been observed in the Upper Kenai River (Hayes and Hasbrouck 1996). The mean weight
was 543.5 grams (range of 252.6 to 1,571.2 grams), and the mean length was 358.4 mm, with a
range of 300 to 500 mm (Figure 5.2-4).
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Table 5.2-6. The date of tagging, transmitter coding, capture method, sex, weight and length of 20 adult
rainbow trout tagging in Grant Creek, Alaska 2013.
Date Channel Code Capture
Method Sex Age Weight (g) Length
(mm)
24-May-13 2 11 Angling Unknown --- 462.6 343
6-Jun-13 17 31 Weir Male 3 1571.2 500
15-Jun-13 2 17 Weir Male 3 767.4 402
17-Jun-13 17 44 Weir Female 6 548.2 357
17-Jun-13 2 12 Weir Female 3 969.4 431
25-Jun-13 17 32 Angling Female 7 406.2 345
28-Jun-13 2 18 Angling Female 3 334.0 309
1-Jul-13 2 21 Angling Female 3 634.0 382
1-Jul-13 17 25 Angling Male 6 252.6 304
3-Jul-13 2 22 Angling Male 7 269.2 309
3-Jul-13 17 45 Angling Male 4 457.8 348
3-Jul-13 17 26 Angling Male 4 551.6 373
4-Jul-13 2 13 Angling Female 3 535.4 357
5-Jul-13 17 33 Angling Female 3 724.8 411
5-Jul-13 2 19 Angling Male 3 398.2 329
7-Jul-13 17 46 Angling Male 3 582.6 385
9-Jul-13 17 37 Angling Female 3 314.4 318
10-Jul-13 17 38 Angling Male 5 487.2 335
11-Jul-13 2 23 Angling Male 3 284.2 300
11-Jul-13 17 27 Angling Male 3 318.0 329
Mean 543.5 358.4
Figure 5.2-4. The length-weight relationship of radio-tagged adult rainbow trout in Grant Creek, 2013.
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During the course of the study, all 20 fish were detected at some time by one of the fixed-
telemetry stations located at the Reach 4/5 break and near the confluence of Grant Creek, or
during one of the mobile telemetry surveys. Of those, four fish were detected within Reach 5
(see Section 5.2.2), while 17 fish were detected at the lower site.
During the course of 37 mobile surveys, a total of 198 contacts were made with radio-tagged
adult rainbow trout within Reaches 1-4 of Grant Creek; 124 contacts in Reach 1, 40 in Reach 2,
31 in Reach 3, and 3 in Reach 4 (Figure 5.2-5). Of the 20 radio-tagged fish, 18 were detected
during mobile surveys. The other two fish that were not detected during mobile surveys were
detected shortly after tagging (three to six hours) by the fixed-telemetry array downstream of the
weir as the fish migrated downstream and exited Grant Creek into the Trail Lake Narrows.
Mobile detections of rainbow trout can be assessed by their location within a reach (i.e.,
mainstem, backwater areas, and side-channels) and habitat type. Of the 124 detections within
Reach 1, all were located within the mainstem, with 23 fish locations noted within pools, and
101 fish locations within riffle habitat (Table 5.2-7). A total of 40 detections occurred within the
Reach 2 mainstem, with 19 fish locations within pool habitat, 13 in riffle habitat, and 8 within
backwater areas. Within the Reach 3 mainstem, 9 detections were observed in pool habitat and
11 in riffle habitat. Within the Reach 3 Predominant Side Channel, three detections were
observed in pool habitat and 11 detections within riffle habitat, and three detections were
recorded in the Reach 3 Secondary Channel within pool habitat. Finally, a total of three
detections were observed in the Reach 4 mainstem; with 1 detection in each of the pool, riffle,
and pocket water habitats.
Table 5.2-7. Habitat use by location based on mobile telemetry surveys for radio-tagged rainbow trout in
Grant Creek, AK, 2014.
Reach - Area Riffle Pool
Back-
Water
Step
Pool Glide
Pocket-
Water Total
1 - Mainstem 101 23 124
2 - Mainstem 13 19 8 40
3 – Mainstem 11 9 20
3 – Predominant Side Channel 5 3 8
3 – Secondary Side Channel 3 3
4 - Mainstem 1 1 1 3
Total 131 58 8 0 0 1 198
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Furthermore, of the 20 radio-tagged rainbow trout, all 20 were detected at some point within
Reach 1 (either by the fixed telemetry station or during mobile surveys). Fourteen of the twenty
tagged rainbow were also detected in reaches two and three, three in Reach 4, and as discussed
previously, four in Reach 5 (Table 5.2-8). The tagged Dolly Varden was not detected at any time
after release.
Table 5.2-8. The number of radio-tagged rainbow trout and Dolly Varden detected by reach within Grant
Creek, Alaska 2013.
Reach Rainbow (n = 20) Dolly Varden (n = 1)
1 20 0
2 14 0
3 14 0
4 3 0
5 4 0
The detections of fish in Reach 1 and 2 occurred throughout the period radio-tagged rainbow
trout were detected within Grant Creek (May 25 through October 17), whereas detections in
Reach 3 occurred primarily shortly after tagging (June 20 through August 15); and the single
detection in Reach 4 occurred on June 28. As discussed in Section 5.2.2.1, no rainbow trout
redds were observed in Grant Creek in 2013. However, due to the poor water clarity and high
flows, that was not unexpected. Detections primarily in Reach 3 shortly after tagging, coupled
with suitable pockets of gravel at the locations of detection may suggest that rainbow trout
spawning possibly occurred in Reach 3; including both the mainstem of Grant Creek and the
secondary channel. The location of detections in Reach 3 for rainbow trout correspond with the
location of observed redds for both sockeye and coho. And while spawning substrates for the
three species varies to some degree, the observations for Chinook, sockeye, and coho indicate
that due to the limited amount of spawning gravel in Grant Creek, the fish will spawn in what
visually appears to be marginal spawning habitat. However, it should be noted that observations
of radio-tagged rainbow in Reach 3 may well have been due to tagged fish taking advantage of
feeding opportunities at those locations.
As can be seen in Figure 5.2-5, the majority of rainbow trout detections were in Reach 1 and to a
lesser extent, the lower portion of Reach 2. These areas were also where the greatest
concentration of sockeye and coho spawned. Detections of rainbow trout in these areas occurred
throughout the tracking period and toward the end of the study. Near the end of the study period,
these areas were the only locations where tagged rainbow resided. These factors indicate that
while it is possible that some rainbow spawned within this area, fish likely resided within this
area to take advantage of feeding opportunities.
Review of the last date of detection by either mobile surveys or the fixed-site telemetry system
provides an opportunity to determine the date of exodus from Grant Creek. Mobile telemetry
surveys continued until tagged fish were no longer detected in Grant Creek, which included
tagged Chinook, sockeye, and coho. The last telemetry survey was conducted on October 29;
however, the date of last detection for rainbow trout during a mobile survey in Grant Creek was
on October 17. Some fish were detected later than October 17 by the fixed-site telemetry system
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near the confluence; but these detections were likely the result of tagged fish travelling
downstream and exiting Grant Creek into the Trail Lake Narrows. For 18 tagged rainbow trout,
the mean and median date of last detection in Grant Creek was September 1, with the earliest
date of exodus being June 17, and the latest date being October 26 (Table 5.2-9). Two additional
fish appear to have expired during the study period. The transmitter of one fish (Fish I.D. 2/17)
was tracked to the general area under a bald eagle nest along the left bank (looking downstream)
of Reach 1 shortly after being tagged. While the transmitter was never recovered, its position
remained constant over the course of several months. The transmitter of a second fish (Fish I.D.
17/31), which had been detected in Reach 5 numerous times, was recovered on shore near a log
jam near the top of the secondary channel in Reach 3. The transmitter antenna had a number of
kinks that appeared to be due to bite marks.
Table 5.2-9. The date of last detection for 18 radio-tagged adult rainbow trout in Grant Creek, Alaska,
2013.
Channel Code Last Date of Detection
2 11 23-Oct-13
2 12 13-Jul-13
2 13 9-Sep-13
2 18 28-Jun-13
2 19 30-Jul-13
2 21 17-Oct-13
2 22 26-Oct-13
2 23 27-Jul-13
17 25 17-Oct-13
17 26 25-Aug-13
17 27 17-Aug-13
17 32 2-Oct-13
17 33 1-Oct-13
17 37 17-Oct-13
17 38 5-Aug-13
17 44 17-Jun-13
17 45 19-Oct-13
17 46 16-Jul-13
Mean: 1-Sep-13
Median: 1-Sep-13
Min: 17-Jun-13
Max: 26-Oct-13
A single Dolly Varden female was surgically implanted with a transmitter on September 10, and
weighed 1,844 grams and was 545 mm FL. This fish was not detected during any mobile
surveys, and was never detected by one of the fixed-telemetry sites. Given the extensive
telemetry surveying of Grant Creek, it is likely that the transmitter either failed after release, or
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the fish was captured by a predator that removed the carcass from the study area. Subsequent
efforts to trap additional Dolly Varden at the weir and through angling proved unsuccessful.
Minnow trapping was used in lower Grant Creek (Reaches 1-4) from April through October to
document species diversity, relative abundance, and distribution. Minnow trapping was also
conducted to help establish important or sensitive juvenile rearing habitat. Over the course of the
study there were 273 individual minnow traps (effort=6,137 hours) placed in different locations
describing fish in distinct reaches, channel locations, and habitat units. Over 3,468 fish were
captured, measured and weighed to describe baseline conditions in lower Grant Creek (Table
5.2-10). The following section discusses the results of this effort from a broad scale (reach) to a
more focused habitat unit basis. The assumption is that CPUE at the reach, channel and habitat
unit scale are a good indicator of relative abundance, distribution and fish-habitat associations.
Table 5.2-10. Number of minnow traps, total effort, and number of fish captured in lower Grant Creek
from April through October 2013.
Lower Grant Creek Minnow Trapping
Reach Number of Traps
Total Effort
(days)
Total Effort
(hrs) Number of Fish
1 63 60.6 1,454.4 899
2 77 72.1 1,713.6 819
3 69 63.6 1,567.2 1,187
4 64 59.4 1,404.0 560
Total 273 255.7 6,139.2 3,465
In lower Grant Creek, relative abundance of fish caught in minnow traps expressed as both
CPUE and proportion of total catch was highest in Reach 3 followed by Reach 1, Reach 2, and
then Reach 4 (Table 5.2-11). The CPUE in the lower gradient reaches (1-4) of Grant Creek were
more than two times the CPUE observed in the higher gradient section of Reach 5 (Table 5.2-
11). This information indicates that juvenile fish were most abundant in lower Grant Creek and
in particular, Reach 3.
Table 5.2-11. Number, proportion, and CPUE for fish caught in Lower Grant Creek from April through
October of 2013.
Reach Number of Fish Proportion CPUE (fish/hr)
1 899 0.26 0.62
2 819 0.24 0.48
3 1,187 0.34 0.76
4 560 0.16 0.40
Total 3,465 1.00 0.56
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Juvenile Chinook and Dolly Varden were the most numerous fish captured in minnow traps on
Grant Creek followed by rainbow trout, coho, sculpins sp. and three-spine sticklebacks (Table
5.2-12). Few juvenile sockeye were captured in minnow traps in either Grant Creek (no fish) or
Trail Lakes Narrows (1 fish) and is likely related to their early life history and behavior. That is,
shortly after emergence sockeye generally tend to migrate into lakes as fry where they feed and
grow (Burgner 1991). The size of post-emergent sockeye fry in Grant Creek would likely have
been too small (<40 mm FL) to effectively capture in Grant Creek. Also, the period of exposure
to minnow trapping would have also been very brief before they emigrated from Grant Creek.
Table 5.2-12. Number, proportion and CPUE of fish caught in lower Grant Creek with minnow traps
from April through October, 2013.
Lower Grant Creek Minnow Trapping
Species Number Proportion CPUE (fish/hr)
Chinook 1,244 0.359 0.20
Dolly Varden 1,142 0.330 0.19
Coho 420 0.121 0.07
Rainbow Trout 397 0.115 0.06
Sculpin sp. 258 0.074 0.04
Three-spine Stickleback 4 0.001 0.00
Grand Total 3,465 1.000 0.56
The relative abundance of fish observed in Grant Creek varied over time. Repeated minnow trap
sampling from April through October in lower Grant Creek showed that relative abundance
increased from fairly low levels in April and May representing late winter and early spring
stream conditions to much higher levels in late spring, summer and fall (June-October) (Figure
5.2-6; Table 5.2-13). In general, peak abundance (catch) occurred during the summer. CPUE for
juvenile Chinook increased from April to a peak in September and declined in October (Figure
5.2-6). Recently emerged Chinook fry (<50 mm FL) were first noted in minnow traps in June
but fry of this size were also noted in July and August. Juvenile Chinook varied in size from 45-
110 mm FL. CPUE for juvenile coho salmon increased steadily from May to a peak in August
and declined in September and October (Figure 5.2-6). Recently emerged coho fry (<50 mm FL)
were first noted in minnow traps in July but fry of this size were also noted in August, September
(1-fish) and October (1-fish). Juvenile coho varied in size from 42-106 mm FL. For Dolly
Varden, the greatest CPUE occurred in June and remained fairly stable in summer and fall. No
Dolly Varden less than 50 mm FL was captured in minnow traps. Dolly Varden varied in size
from 52-165 mm FL. Catch of juvenile rainbow trout decreased from April to June and remained
relatively low into July and August. In September and October there was a noticeable increase
in juvenile rainbow trout. Small rainbow trout fry (<50 mm FL) were noted in April (1-fish),
May (2-fish) and June (1-fish). However, the majority of small rainbow trout fry were observed
in September and October. Rainbow trout varied in size from 43-146 mm FL.
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Figure 5.2-6. CPUE for juvenile Chinook, coho, Dolly Varden and rainbow trout from minnow trapping
in lower Grant Creek from April through October, 2013.
Table 5.2-13. Numbers of fish collected from minnow trapping in lower Grant Creek from April through
October 2013.
Fish Species
Month
Apr May Jun Jul Aug Sep Oct Total
Chinook 33 24 15 120 280 484 288 1,244
Coho 0 2 20 37 202 93 66 420
Dolly Varden 14 17 371 174 220 143 203 1,142
Rainbow Trout 46 34 10 18 32 92 165 397
Sculpin sp. 19 7 35 40 50 29 78 258
Three-spine Stickleback 0 0 1 1 2 0 0 4
Total 112 84 452 390 786 841 800 3,465
Most of the patterns of change in fish abundance and CPUE over time is likely the result of new
recruits (age-0 fish) that become available for capture (>40 mm FL) in minnow traps post
emergence in spring (Chinook and coho) or summer (rainbow trout). What is less apparent is the
increase in abundance of Dolly Varden, which is likely explained in part, by new recruits but
also habitats that became available (side channels) as flows increased. The low catch of most
fish during April and May does not appear to be a bias in sampling method and comports well
with snorkel observations at those times.
0.00
0.10
0.20
0.30
0.40
0.50
0.60
APR MAY JUN JUL AUG SEP OCTCPUE (fish/hr)Month
Lower Grant Creek
CPUE of salmonids captured in minnow traps
Reaches 1-4 Combined
Chinook Coho Dolly Varden Rainbow Trout
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Most fish that occur in Grant Creek were present in all reaches of lower Grant Creek (Table 5.2-
14). No juvenile sockeye or arctic grayling were captured in lower Grant Creek. There were a
few three-spine sticklebacks captured in lower Grant Creek (reaches 1 and 3). The number of
Chinook and Dolly Varden captured in lower Grant Creek was similar as was the number of
coho and rainbow trout.
Table 5.2-14. Number of fish captured in minnow traps in different reaches of lower Grant Creek from
April through October 2013.
Fish Species
Lower Grant Creek Reaches (Number)
Total 1 2 3 4
Chinook 370 351 390 133 1,244
Coho 89 116 176 39 420
Dolly Varden 306 150 418 268 1,142
Rainbow Trout 75 115 126 81 397
Sculpin sp. 57 87 75 39 258
Three-spine Stickleback 2 0 2 0 4
Total 899 819 1,187 560 3,465
In lower Grant Creek, CPUE was highest (0.758 fish/hr.) in reach 3 for all fish except sculpins
(Table 5.2-15). CPUE for juvenile Chinook was similar in reaches 1 and 2, but for coho the
capture rate was nearly twice as high in Reach 3 as other reaches. For rainbow trout, capture
rates were fairly uniform in all reaches of lower Grant Creek. Similar to Chinook, Dolly Varden
had the highest capture rates in reaches 1 and 3. Unlike Chinook, Dolly Varden had a higher
capture rate in Reach 4 than in Reach 2. In lower Grant Creek the capture rates for sculpins was
fairly uniform across all reaches. The capture rates presented for lower Grant Creek indicate that
there may be some channel or habitat characteristics within different reaches preferred by some
fish species.
Table 5.2-15. CPUE for fish captured in minnow traps in different reaches of lower Grant Creek from
April through October 2013.
Fish Species
Lower Grant Creek Reaches (CPUE)
Total 1 2 3 4
Chinook 0.254 0.203 0.256 0.093 0.203
Coho 0.061 0.067 0.115 0.027 0.068
Dolly Varden 0.210 0.087 0.274 0.188 0.186
Rainbow Trout 0.052 0.066 0.083 0.057 0.065
Sculpin sp. 0.039 0.050 0.049 0.027 0.042
Three-spine Stickleback 0.001 0.000 0.001 0.000 0.001
Total 0.618 0.473 0.778 0.393 0.564
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Capture rates were assessed for juvenile fish in lower Grant Creek by location within the active
channel and habitat unit. Channel descriptors were used to describe the location of three broad
categories: side channels areas, backwater areas or mainstem areas.
In lower Grant Creek, CPUE was highest in side channel areas followed by backwater areas and
then locations within the main stream channel (mainstem) (Figure 5.2-7). Side channels occur
mostly in Reaches 1 and 3 and backwater areas occur only in Reaches 2 and 3. Aquatic habitats
are discussed in more detail in the Instream Flow Study, Final Report (KHL 2014a).
Figure 5.2-7. CPUE for fish captured in minnow traps placed in backwater, side channel and mainstem
areas of lower Grant Creek from April through October 2013.
Capture rates for salmonids varied within channels types of lower Grant Creek (Figure 5.2-8).
For juvenile Chinook and coho, capture rates were highest in backwater areas while Dolly
Varden and rainbow trout CPUE was the highest in side channels. Mainstem areas dominated by
riffle habitat had the lowest CPUE for juvenile Chinook and coho. Dolly Varden had the lowest
capture rates in backwater areas and rainbow trout capture rates were the same in both mainstem
and backwater areas.
0.77
0.48
0.85
0.00
0.25
0.50
0.75
1.00
Backwater Areas Mainstem Areas Side Channel AreasCPUE (fish/hr)Channel Location
Lower Grant Creek
CPUE for all fish
within channel areas
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Figure 5.2-8. CPUE for salmonids captured in minnow traps placed in backwater, side channel and
mainstem areas of lower Grant Creek from April through October 2013.
In lower Grant Creek, CPUE for salmonids varied by species and habitat unit type (Figure 5.2-9).
Catch rates for juvenile Chinook were nearly equal between pools and glides and the least in
riffles and pocket water. For coho, the catch rate was highest in pools followed by riffles. No
coho were captured in glides. Catch rates for Dolly Varden were highest in glides and runs and
lowest in riffle habitat. Juvenile rainbow trout had the highest catch rates in glides and pocket
water and was the least in pool habitat. The high catch rates in glide and run habitats are
somewhat counterintuitive with basic habitat preferences for most juvenile salmonids. Both of
these habitat types were rare in lower Grant Creek.
0.361
0.175
0.228
0.166
0.046
0.1140.115
0.163
0.360
0.062 0.062
0.081
0.000
0.100
0.200
0.300
0.400
0.500
Backwater Areas Mainstem Areas Side Channel AreasCPUE (fish/hr)Channel Location
Lower Grant Creek
CPUE for salmonids within
Channel Areas
Chinook
Coho
Dolly Varden
Rainbow Trout
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Figure 5.2-9. CPUE for salmonids captured in minnow traps placed in different habitat unit types of
lower Grant Creek from April through October, 2013.
Minnow trapping in lower Grant Creek showed that salmonids were present in all reaches of
lower Grant Creek with the highest catch rate (0.778 fish/hr) noted in Reach 3. Reach 3
contained all channel types (mainstem, backwater and side channels), which increases both
channel and habitat diversity compared to other reaches. The capture rates of salmonids in lower
Grant Creek indicate that side channel and backwater areas are important rearing areas (Figure
5.2-7). In particular, catch rates for juvenile Chinook, coho and Dolly Varden were highest in
these channel locations likely because large woody debris or greater depth and/or lower
velocities provided good juvenile rearing habitat (Figure 5.2-8). Juvenile coho and Chinook tend
to prefer large, deep pools with abundant cover (McMahon 1983; Raleigh et al. 1986). Capture
rates for rainbow trout were much more even by reach, channel and habitat designation.
Rainbow trout, as generalist, appear to have similar requirements for abundant cover but depth
(pool habitat) may be less important (Raleigh et al. 1984).
Nighttime snorkeling was used in both April and May to assess species diversity, distribution
and relative abundance of fish in lower Grant Creek. From June through October, the water was
too turbid to snorkel effectively. In April, low flows (18 cfs) and cold water (0.5-1.5°C) were the
prevailing stream conditions. In May, both flow (150 cfs) and water temperature (4.0°C) had
increased. These conditions are a good approximation of winter and early spring stream
conditions in lower Grant Creek.
In mid-April, most salmonids were observed in pool habitat available in the mainstem and
backwater areas of lower Grant Creek (Table 5.2-16). The highest fish density (fish/100 m2)
occurred in backwater areas available in Reach 3. Backwater areas in Reach 2 were frozen over
0.2516
0.0798
0.2436
0.1854
0.0000
0.000
0.100
0.200
0.300
0.400
Glides Pocket water Pools Riffles RunsCPUE (fish/hr)Habitat Types
Lower Grant Creek
CPUE for Juvenile Chinook by
Habitat Type
0.0000 0.0114
0.0949
0.0587
0.0153
0.000
0.100
0.200
0.300
0.400
Glides Pocket water Pools Riffles RunsCPUE (fish/hr)Habitat Types
Lower Grant Creek
CPUE for Juvenile Coho by
Habitat Type
0.3648 0.2357 0.2328 0.1309 0.6881
0.000
0.100
0.200
0.300
0.400
Glides Pocket water Pools Riffles RunsCPUE (fish/hr)Habitat Types
Lower Grant Creek
CPUE for Juvenile Dolly Varden by
Habitat Type
0.0943
0.0722
0.0217 0.0375
0.0000
0.000
0.100
0.200
0.300
0.400
Glides Pocket water Pools Riffles RunsCPUE (fish/hr)Habitat Types
Lower Grant Creek
CPUE for Juvenile Rainbow Trout by
Habitat Type
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and inaccessible to snorkeling. Riffle habitat had the lowest fish densities in lower Grant Creek.
Side channel habitat was covered in snow and ice and was not available for sampling via night
time snorkel surveys. Pool habitat (mainstem and backwater) that occurs in lower Grant Creek
provides important overwinter habitat.
Table 5.2-16. Number and density of salmonids observed during night time snorkel surveys in lower
Grant Creek in April 2013.
Month Channel Habitat
Species
Total
Total Area
Sampled
(m2)
Fish Density
(fish/100 m2) Chinook Coho
Dolly
Varden
Rainbow
Trout
April
Mainstem
Glide 23 0 2 17 42 933.2 4.50
Pool 202 0 15 140 357 7,192.6 4.96
Riffle 5 0 2 32 39 8,462.5 0.46
Backwater Pool 46 1 1 35 83 793.6 10.46
Total 276 1 20 224 521 17,381.9 3.00
Juvenile Chinook were the most abundant fish observed in lower Grant Creek followed by
rainbow trout, Dolly Varden, and coho. Almost all juvenile Chinook observed were within the
size range of 60-80 mm FL (Table 5.2-17). A few juvenile Chinook (4 fish) were in observed in
the 80-100 mm FL size class. All juvenile Chinook observed in April are likely age-1 fish that
overwintered in mostly pool habitats of lower Grant Creek. No juvenile Chinook fry (< 40 mm)
or age-0 fish were observed in April. Rainbow trout varied in size from about 40-180 mm FL.
Most were observed within the size class of 100-120 mm FL. It is reasonable to assume that
several age classes overwintered in pool habitat of lower Grant Creek. There were few Dolly
Varden and a single coho observed in lower Grant Creek in April. Dolly Varden varied in size
from 40-160 mm FL and the single coho that was observed was within the 40-60 mm size class.
There were probably several age classes of Dolly Varden overwintering in lower Grant Creek.
Night time snorkel observations appear to comport well with minnow trapping that occurred in
April. Juvenile Chinook and rainbow trout were the most abundant salmonids observed in April
while Dolly Varden and coho were less abundant.
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Table 5.2-17. Abundance of salmonids observed in 20-mm increments during night time snorkels surveys
in lower Grant Creek in April and May 2013.
Month Species
Size Classes (20-mm FL increments)
Total
40
(20-40)
60
(40-60)
80
(60-80)
100
(80-100)
120
(100-120)
140
(120-140)
160
(140-160)
180
(160-180) >180
April
Chinook 0 0 272 4 0 0 0 0 0 276
Coho 0 1 0 0 0 0 0 0 0 1
Dolly Varden 0 1 4 11 3 0 1 0 0 20
Rainbow Trout 1 17 31 56 73 32 11 3 0 224
Total 1 19 307 71 76 32 12 3 0 521
May
Chinook 0 2 161 42 0 0 0 0 0 205
Coho 0 4 7 1 0 0 0 0 0 12
Dolly Varden 0 0 0 1 2 2 0 0 0 5
Rainbow Trout 0 7 1 9 55 48 20 17 21 178
Total 0 13 169 53 57 50 20 17 21 400
In mid-May, as flows and temperature increased most salmonids were still observed in pool
habitat available in the mainstem, backwater, and side channel areas of lower Grant Creek (Table
5.2-18). Chinook and rainbow trout were still the most abundant fish observed in lower Grant
Creek in May. There were a few Dolly Varden and coho observed. Pools in backwater areas
had the highest fish density while riffles in the mainstem areas had the lowest fish density.
Interestingly, riffle habitat in side channels had the second highest fish density in May. Glide
habitat (non-turbulent fast water) classified in April had become turbulent and less glide-like
with increased flows in May.
Table 5.2-18. Number and density of salmonids observed during night time snorkel surveys in lower
Grant Creek in May 2013.
Month Channel Habitat
Species
Total
Total Area
Sampled
(m2)
Fish Density
(fish/100 m2) Chinook Coho
Dolly
Varden
Rainbow
Trout
May Mainstem Pool 98 1 2 99 200 6,138.6 3.26
Riffle 0 0 0 2 2 1,226.3 0.16
S. Channel Pool 6 0 1 34 41 1,137.1 3.61
Riffle 7 1 0 22 30 676.1 4.44
Backwater Pool 94 10 2 21 127 1,111.4 11.43
May Total 205 12 5 178 400 10,289.5 3.89
Three different size classes of juvenile Chinook were observed in lower Grant Creek (Table 5.2-
17). The 40-60 mm FL (2-fish) likely represent recent emerged age-0 fish while Chinook greater
than 60 mm FL (203-fish) represent age-1 juvenile Chinook. Chinook emergence had probably
started in May. In May, the range in coho size was similar to Chinook but with fewer fish. Coho
emergence may have also begun in May. Rainbow trout varied in size from about 40 mm to
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greater than 180 mm FL. Most (161-fish) were observed within the size classes greater than 100
mm FL. From April to May, there was an increase in the number of larger rainbow trout in
lower Grant Creek. Some of the shift in abundance of larger rainbow trout might be explained by
growth but it is likely that feeding and spawning opportunities were bringing larger fish into
Grant Creek. The number of Dolly Varden observed from April to May decreased and there
were fewer small fish observed. The low abundance of Dolly Varden observed by both
snorkeling and minnow trapping in winter and early spring might suggest that the higher
abundance of Dolly Varden observed later in the year might be the result of both new
recruitment and immigration into lower Grant Creek.
The lower incline plane trap was installed on April 30, 2013 and was in operation until October
16, 2013. The trap typically operated 24 hours per day, seven days per week, with few
exceptions. The trap was not fished the first two weekends of operation (May 4-5 and May 11-
12) since few fish were being captured by the trap. Trapping operations were suspended on three
occasions: June 18-23 due to high flows that created safety issues for crews accessing the trap as
well as an influx of debris due to bank flooding; September 11-15, also due to high flows and
debris; and October 14 due to wind storms that resulted in an excessive amount of leaf litter in
the trap. In each of these cases, trap operation was compromised during the period leading up to
the time of outage. Throughout the study, the incline plane trap was checked and cleaned at least
twice per day, and more frequently when necessary. During the period leading up to the June
18-23 outage, personnel remained on site 24 hours per day, and the trap was checked and cleaned
approximately every 3 to 4 hours. During other periods of high debris load, CIAA staff assisted
in the maintenance of the trap by checking and cleaning it typically at 2200 hours and 0200
hours.
As the juvenile migration progressed, it became apparent due to the absence of sockeye fry being
captured that the incline plane trap was either not capturing fry sized fish, or it was not retaining
them in the live box once captured. Salmonid fry were being observed along the margins of
Grant Creek where the foot trails had been flooded. However, few fry sized fish were captured
in the trap, nor were they being captured in the minnow traps. Both the incline plane trap’s live
box and the minnow traps were constructed with 0.6 cm square mesh. Through a series of tests,
it became apparent that fry sized fish could escape the incline plane and minnow traps once
entrained. As such, both incline plane traps were modified by installing 0.3 cm mesh in critical
areas, and installing aluminum flashing around the bottom of the live box to create a sanctuary
for captured fish. After these modifications, some fry sized fish were captured in the trap; albeit
probably after the majority of the sockeye fry migrated into the Trail Lakes system.
In addition to trap outages and the initial poor efficiency in capturing fry sized fish, another
complicating factor hindered the trapping of juvenile fish at the incline plane trap as they
migrated out of Grant Creek. Upstream of the incline plane trap, located on the left bank is a
distributary that at higher flows becomes watered, and which juvenile fish can migrate
downstream bypassing the incline plane trap. This channel begins to overflow at approximately
426 cfs, and meanders in a southeasterly direction and eventually dumps directly into Lower
Trail Lake without reconnecting to Grant Creek. During periods of flow, this channel was
sampled using minnow traps, and contained a relatively high density of juvenile salmonids,
suggesting its use as a migratory corridor. Because of this distributary, it was necessary to assess
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the need to block the juvenile migration into two periods; a period of relatively lower flow (≤
425 cfs) when the distributary was “dry”, and a period of higher flow (≥ 426 cfs), when the
distributary was “wet”. Furthermore, it was necessary to calculate trap efficiency for each
species separately for each flow period in order to estimate juvenile abundance within Grant
Creek. Based on the season-wide estimator described in Section 4.2.3, we calculated trap
efficiencies for the lower incline plane trap. Estimation of abundance assumes that all fish used
to estimate trap efficiency were active migrants; that there was no mortality between the release
location and the incline plane trap; and that the marked fish behaved as the natural population
would, that is, they distributed naturally within Grant Creek. To meet these requirements, the
release location was selected based on guidelines described in Volkhardt, et al. (2007).
As can be seen in Table 5.2-19, ample numbers of Chinook, coho, and Dolly Varden were
released to provide a season wide estimate of trap efficiency. However, collectively only 12
sockeye were released, with no recoveries. As such, it is not possible to get an abundance
estimate for sockeye in Grant Creek. Likewise, only 13 rainbow trout were marked and released,
with a single recovery. For rainbow, it is also not possible to estimate Grant Creek abundance.
An additional point of interest is that during periods of higher flow, when migrating juveniles
had the opportunity to utilize the upstream distributary, the capture efficiency was actually
higher than when the channel was dry. This seems counter intuitive; however, this observation is
consistent across all species. While undoubtedly a portion of the outmigrating salmonids were
diverted into the distributary, the higher flows may have improved conditions that diverted
juvenile fish that did not enter the distributary into the trap, resulting in higher trap efficiencies
for all species.
Table 5.2-19. The number of fish released and recovered by species for the two flow blocks and their
corresponding trap efficiencies.
Species
Low Flow Condition High Flow Condition Trap Efficiency
Release Recapture Release Recapture Low High
Chinook 380 45 68 10 0.118 0.147
Coho 169 19 110 13 0.112 0.118
Sockeye 3 0 9 0 0.000 0.000
Dolly Varden 248 2 571 41 0.008 0.072
Rainbow Trout 8 0 5 1 0.000 0.200
To determine whether it was necessary to block the data into the high and low flow periods, a
test of homogeneity based on a chi-square test of 1 degree freedom using a 2 x 2 contingency
table was performed:
High Low
Caught r1 r2
Not caught R1 – r1 R2 – r2
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Where:
R = the total number of fish released during trap efficiency trials; and
r = the number of R recaptured at the trap.
The tests of homogeneity during high and low flow conditions found no difference for Chinook
and coho salmon; however, there was a flow effect for Dolly Varden. Therefore, a single
estimate of trap efficiency was used to estimate abundance for Chinook and coho (0.123 and
0.115, respectively), whereas two seasonal estimates of trap efficiency were used for Dolly
Varden (0.008 during the low flow period, and 0.072 during the high flow period).
Since there were a few data gaps due to the incline plane trap being down during high flow and
debris conditions, missing days of data were extrapolated based on the calculations described in
Appendix 1. The following table presents estimates of abundance for Chinook, coho, and Dolly
Varden in Grant Creek, which represents all of Grant Creek upstream of the lower incline plane
trap, including Reach 5 (Table 5.2-20).
Table 5.2-20. The number of juvenile migrants by species captured within the lower incline plane trap,
and corresponding abundance estimates and standard errors based on capture efficiencies in Grant Creek.
Statistic Chinook Coho
Dolly Varden
Low Flow High Flow Total
Observed n 577 360 296 673 Est. N 4,797.6 3,164.9 36,766.0 9,665.2 46,431.2
S.E. N 603.2 546.2 25,979.5 1,470.9 26,021.1
These values should be considered as estimates for parr sized fish only. That is, until the early
part of July the incline plane trap was ineffective at catching fry sized fish (≤ 50 mm). By the
time the incline plane trap had been fixed, the majority of fry sized fish (i.e., sockeye fry) had
already migrated out of Grant Creek.
While an estimate of abundance for Dolly Varden is included, this species exhibits a different
life history compared to Chinook, coho, or sockeye. Chinook and coho typically emigrate as
both sub-yearlings and yearlings while sockeye migrate out shortly after emergence as sub-
yearlings. Dolly Varden on the other hand may rear in small spawning streams for up to 4 years.
As such, for Dolly Varden only a small portion of each year class were likely sampled, excluding
of course sub-yearlings, which would not have been captured in the trap until after it had been
modified. As a final note, the abundance estimates are for the geographical area from the Grant
Creek Falls to the lower incline plane trap; which excludes approximately 210 meters from the
trap to the Grant Creek confluence. This latter portion of Grant Creek has the highest density of
observed spawning for all species of salmonids in Grant Creek; for which the progeny of these
spawners would not be captured by the incline plane trap.
Based on fish size and time of sampling at the lower incline plane trap it is clear that juvenile
salmonids of multiple age classes over-wintered in Grant Creek (Figure 5.2-10). For juvenile
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Chinook, most fish were in the 80 mm range beginning about May 15. These fish are yearling
Chinook that have overwintered in Grant Creek. This observation is supported by snorkel
surveys conducted in April and May where juvenile Chinook (age-1) were commonly observed.
Later, from June to the beginning of August, there appears to be two predominant size classes of
juvenile Chinook captured in the trap. The larger individuals of the migration were in the 100-
110 mm size class and represent yearling fish. The smaller individuals were around 50-80 mm,
which would be consistent with sub-yearling fish. Later, in mid-August, there is a broad
distribution of size for juvenile Chinook, and indicates a dominant subyearling migration with
fewer yearling fish migrating out of Grant Creek.
For coho salmon juveniles, very few individuals were captured in the trap until the latter part of
July (Figure 5.2-10). The fish that were captured earlier in the migration (end of May) however,
were in the 60 mm range, and were likely over-wintering yearling fish. Later (early July through
early September), coho juveniles ranged in size of 50-100 mm, and likely represent both sub-
yearling and yearling fish. From these data, it appears that there were a few coho that over-
wintered in Grant Creek. This observation is supported by few juvenile coho being observed
during snorkel surveys in April and May.
For rainbow trout, based on the size distribution it appears that multiple year classes were
captured early during the spring migration (i.e., mid-May to early June). As spring spawners,
rainbow trout fry emerge in the summer, and due to cold water temperatures they do not grow
substantially during the winter months. In Figure 5.2-10, it appears that there are at least two
size classes of fish captured at the lower incline plane trap in the spring. There were individuals
in the 50 mm size range that had overwintered in Grant Creek emerging the previous summer
(brood year 2012). In the spring, there were also individuals in the 80-120 size range that likely
emerged two years ago (i.e., brood year 2011). In the fall, rainbow trout had a similar size range
indicating age-0 fish had recently emerged in the summer of 2013 and some individuals the
previous year (age-1+).
For Dolly Varden, juveniles in the range of 80-110 mm were captured beginning mid-May. This
indicates substantial over-wintering for Dolly Varden juveniles, which was substantiated with
snorkel surveys in April and May. The abundance of migrating Dolly Varden was greatest in
July and likely represents multiple age classes.
Collectively, a total of 3,942 fish were processed at the lower incline plane trap (this total does
not include extrapolated numbers to account for trap outages); and includes 577 Chinook, 360
coho, 22 sockeye, 969 Dolly Varden, 36 rainbow trout, 833 sculpin (both slimy and coast range),
1,089 three-spine stickleback, and 56 round whitefish. Figure 5.2-11 shows the emigration
period of Chinook, coho, and Dolly Varden, respectively. Sockeye have not been included in
this analysis as the majority of sockeye migrating out of Grant Creek were likely not captured at
the trap due to deficiencies associated with the trap prior to the early July retrofitting and the
small size and likely rapid outmigration of sockeye to the Trail Lake system.
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Figure 5.2-10. The distribution of size by date for Chinook, coho, rainbow trout, and Dolly Varden
captured in the lower incline plane trap, Grant Creek, Alaska 2013.
0
50
100
150
200
5/1/2013 6/20/2013 8/9/2013 9/28/2013Length (mm)Date
Chinook
0
50
100
150
200
5/1/2013 6/20/2013 8/9/2013 9/28/2013Length (mm)Date
Coho
0
50
100
150
200
5/1/2013 6/20/2013 8/9/2013 9/28/2013Length (mm)Date
Rainbow Trout
0
50
100
150
200
5/1/2013 6/20/2013 8/9/2013 9/28/2013Length (mm)Date
Dolly Varden
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Figure 5.2-11. Emigration timing for Chinook, coho, and Dolly Varden juveniles at the Lower Incline
Plane Trap in Grant Creek, Alaska, 2013. Estimated or extrapolated values are highlighted red.
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5.3 Trail Lake Narrows Fish and Aquatic Habitats
The Trail Lake Narrows was sampled in July to assess species diversity and relative abundance.
Minnow trapping, beach seining and angling were employed to describe baseline conditions in
an area of potential impact associated with the installation and use of an access road into the
Project Area (Figure 5.3-1). Minnow traps were set in 13 locations with a total fishing effort of
1,133 hours capturing 381 fish (Table 5.3-1).
Table 5.3-1. Number of minnow traps, total effort, number of fish captured and CPUE in the Trail Lake
Narrows in July 2013.
Lower Grant Creek Minnow Trapping
Reach
Number of
Traps
Total Effort
(days)
Total Effort
(hrs.)
Number of
Fish
CPUE
(fish/hr.)
Trail Lake Narrow 52 47.2 1,133 381 0.34
Juvenile Chinook and three-spine sticklebacks were the most numerous fish captured in minnow
traps followed by coho, Dolly Varden, sculpins sp., rainbow trout and sockeye (Table 5.3-2).
CPUE for Chinook and coho was lower in the Trail Lake Narrows than Reaches 1-4 of Grant
Creek but greater than Reach 5 of Grant Creek. CPUE for Dolly Varden and rainbow trout in the
Trail Lake Narrows was less than all reaches of Grant Creek. Juvenile Chinook captured in
minnow traps in July varied in size from 45-121 mm FL indicating that both age-0 and age-1 fish
were present. Coho varied in size from 45-97 mm FL. The size range for coho also suggests that
age-0 and age-1 fish resided in the Trail Lake Narrows. Rainbow trout varied in size from 63-71
mm FL. Dolly Varden varied in size from 57-184 mm FL, which likely represents several age
classes.
Table 5.3-2. Number, proportion and CPUE of fish caught in the Trail Lake Narrows with minnow traps
in July 2013.
Lower Grant Creek Minnow Trapping
Species Number Proportion CPUE (fish/hr)
Chinook 108 0.283 0.095
Dolly Varden 52 0.136 0.046
Coho 62 0.163 0.055
Rainbow Trout 4 0.010 0.004
Sockeye 1 0.003 0.001
Sculpin sp. 38 0.100 0.034
Three-spine Stickleback 116 0.304 0.102
Grand Total 381 1.000 0.336
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Beach seining was employed at night in three locations where lower velocities and small
substrates were conducive to this sampling method. Juvenile Chinook were the most abundant
fish captured in beach seines followed by round whitefish and sculpins (Table5.3-3). Other
species made up less than five percent of the catch and no coho were captured using beach
seining.
Table 5.3-3. Number and proportion of catch for fish seined in beach areas of the Trail Lake Narrows in
July 2013.
Species Abundance Proportion
Chinook 100 0.58
Dolly Varden 2 0.01
Rainbow Trout 2 0.01
Sculpin sp. 27 0.16
Sockeye 4 0.02
Three-spine Stickleback 5 0.03
Round Whitefish 33 0.19
Total 173 1.00
Seven angling stations were used to capture fish within the Trail Lake Narrows area (Table 5.3-
4). Single, barbless hooks on spinners were used, which allowed the expeditious release of adult
salmon (Chinook, sockeye or pink) that were known to be in the area. However, no adult salmon
were captured. There was a total of 13 adult trout/char that were hooked, with five of those fish
being captured (effort=1 hr./station) for a CPUE of 0.7 fish/hr. Fish that were identified as
salmonids were fish that came off the hook close enough to the angler to be identified (4fish).
Some fish came off the hook much closer to the angler and species and an estimate of length
could be provided (4fish). Five fish were captured and measured for length and weight before
release.
Adult salmon, rainbow trout and Dolly Varden occur in the Trail Lakes Narrows area, which is
also an upstream migration corridor for fish destined to spawn in Grant Creek and all other
tributaries of upper Trail Lake. Likewise, this area is also a downstream migration corridor for
salmonid production upstream. Dolly Varden and rainbow trout probably reside in the area
taking advantage of juvenile salmon that migrate through or reside in this area. Juvenile Chinook
were the most numerous fish captured with minnow traps and beach seines.
Spawning may also occur in this area; depressions (redds) were observed in suitable spawning
gravels and sockeye carcasses were recovered in the area that had not been previously sampled.
The redds could only be observed after water levels had resided in October.
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Table 5.3-4. Angling station and number and size and weight of rainbow trout and Dolly Varden
observed in July 2013.
Station Species Length (mm FL) Weight (g)
1
Rainbow Trout 343 424.2
Rainbow Trout 299 241.8
Dolly Varden 180 NA
Dolly Varden 160 NA
Salmonid NA NA
2
Dolly Varden 240 NA
Rainbow Trout 301 294.0
Salmonid NA NA
3 Salmonid NA NA
Salmonid NA NA
4 Dolly Varden 268 191.0
5 No Fish - -
6 Rainbow Trout 381 523.8
Rainbow Trout 220 NA
7 No Fish - -
6 CONCLUSIONS
In the section that follows, we summarize the results of fisheries research conducted on Grant
Creek in 2013, and describe potential areas of sensitivity that may be affected by hydroelectric
development and systems operation.
6.1 Summary of Grant Creek Research
6.1.1 Anadromous Adult Salmonids
Escapement - The key species of adult salmon returning to Grant Creek include pink, Chinook,
sockeye and coho salmon. Sockeye salmon were the dominant run entering Grant Creek with
1,117 fish counted above the weir. There were also 10 pink, 23 Chinook and 237 coho salmon
counted above the weir. Estimates of salmon escapement based on visual counts (AUC) were
within ±12 percent of the weir counts for returning salmon. The estimated escapement based on
visual counts for the entire stream were 90 Chinook, 1,169 sockeye and 252 coho salmon.
The estimates for sockeye and coho appeared to be reasonable based on the spawning activity
observed below the weir. However, the difference in the Chinook weir count (23 fish) and the
estimate for the entire stream (90 fish) implied that 67 additional Chinook spawned downstream
of the weir. That estimate appears to be high based on the spawning activity observed below the
weir. An estimate of 46 Chinook is a more realistic estimate based on the fish per redd ratio of
7.6 fish/redd that was observed above the weir in 2013.
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Run Timing – The period of adult salmon migration into Grant Creek occurs from the end of
July and extends over a 13 week period to near the end of October. Pink salmon passed the weir
on Grant Creek from the first week of August to the end of August. Chinook salmon passed the
weir from the second week of August through the first week of September. Peak passage for pink
and Chinook salmon occurred during the weeks of August 4 and August 11, respectively. The
adult migration for sockeye occurred over a ten week period from the last week of July to the
second week of October. Peak passage for sockeye occurred at the end of August. Coho salmon
began entering Grant Creek the second week of September, peaked the first week of October and
ended the last week of October. Run timing for Chinook and sockeye in 2013 was at least 1 week
earlier than observed in 2009 (HDR 2009b). The sensitive time period based on run timing for
adult salmon extends from the last week of July to the last week of October.
Spawning Timing and Distribution – The period of salmon spawning activity in Grant Creek
extends over 13 weeks from first week of August to end of October. Pink salmon began
spawning in early August with two redds constructed in Reach 1 of Grant Creek. Pink salmon
were not observed in Grant Creek during 2009 visual surveys (HDR 2009b). Chinook salmon
began spawning in mid-August and built six redds in a three week period. Sockeye began
spawning at the end of August building 308 redds within the first two weeks. Sockeye spawning
activity was noted until the last week of September. Coho began spawning the first week of
October and were complete at the end of the month constructing 72 redds in Grant Creek. The
sensitive time period for adult salmon based on spawning was from the first week of August to
the end of October.
The majority (95 percent) of critical spawning habitat was concentrated within Reaches 1-3 of
Grant Creek. Most (62 percent) documented redds were located in the mainstem areas primarily
within riffle (62 percent) and pool (13 percent) habitats. Spawning also occurred in side channels
(16 percent) and backwater areas (8 percent). In Reach 1, spawning for pink, sockeye and coho
salmon most often occurred in riffle and pool habitat along the stream margins in the mainstem
areas away from the thalweg and the highest stream velocities. Chinook spawned only in riffle
habitat most often mid-channel where higher velocity and larger spawning substrates occurred.
In Reach 2, most spawning occurred in mainstem riffle habitat along the stream margins for
sockeye and coho salmon. Irregularities along the stream margin of riffle habitat created areas of
lower velocity and suitable spawning substrate. Sockeye and coho also spawned in the stream
margins of some pool habitat of Reach 2. In Reach 3, most spawning occurred in pool habitat in
mainstem and side channel areas. One large backwater area was also used by sockeye and coho
salmon. Spawning activity in Reach 4 was fairly low (4 percent) but did occur in riffle habitat
along the stream margins of the right bank. Spawning also occurred along the left bank in pocket
water. Spawning in Reach 5 was also low (1 percent) and occurred along the stream margins in
step pool habitat in the lower end of the reach.
6.1.2 Resident Adult Salmonids
Run Timing and Abundance – Rainbow trout and Dolly Varden are identified as key species
migrating into Grant Creek. The period of migration for rainbow trout lasted 6 weeks from the
end of May to the end of June. The weir was not operational at the start of May, which could
extend the period of migration by at least three weeks. There were 13 adult rainbow trout that
passed the weir on Grant Creek. The abundance estimate is probably low considering the lack of
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coverage early in the season and based on undocumented passage of previously tagged fish. The
migration period for Dolly Varden lasted 4 weeks from mid-August to mid-September. There
were 14 Dolly Varden that passed the weir on Grant Creek.
Spawning Distribution - Of the 20 adult rainbow trout that were surgically implanted with radio
transmitters, three males and one female were detected within Reach 5 subsequent to their
release. Based on radio telemetry mobile surveys and detections by the fixed-site system at the
Reach 4/5 break, it does not appear that any of the radio-tagged rainbow trout spawned within
Reach 5. However, while no redds or adult rainbow trout were observed during surveys of
Reach 5, given the poor water clarity, the probability of spotting live fish or redds was extremely
low. Furthermore, no rainbow trout redds were observed anywhere within Grant Creek in 2013.
The fact that suitable gravel exists in Reach 5 to support rainbow spawning, and the fact that
rainbow trout fry were captured in minnow traps within Reach 5 strongly suggests that spawning
does occur within this portion of Grant Creek; to what extent, however, is unknown.
It should be noted that it is possible that many of the tagged rainbow trout were not in spawning
condition. The original intent was to have the weir operational on May 1, as rainbow will begin
their spawning migration when stream temperatures reach about 4° C. However, due to a variety
of factors, including high flows and the undercut bank discussed in Section 4.1.1, the weir was
not fully functional until early July. Prior to that time, it is highly likely that a proportion of the
rainbow trout that migrated past the weir was not intercepted, and therefore a proportion of the
spawning population was missed.
The detections of fish in Reach 1 and 2 occurred throughout the period radio-tagged rainbow
trout were detected within Grant Creek (May 25 through October 17), whereas detections in
Reach 3 occurred primarily shortly after tagging (June 20 through August 15); and the single
detection in Reach 4 occurred on June 28. As discussed in Section 5.2.2.1, no rainbow trout
redds were observed in Grant Creek in 2013. However, due to the poor water clarity and high
flows, that was not unexpected. Detections primarily in Reach 3 shortly after tagging, coupled
with suitable pockets of gravel at the locations of detection suggest that it is possible that
rainbow trout spawned in Reach 3; including both the mainstem of Grant Creek and the
secondary channel. The location of detections in Reach 3 for rainbow trout correspond with the
location of observed redds for both sockeye and coho. And while spawning substrates for the
three species varies to some degree, the observations for Chinook, sockeye and coho indicate that
due to the limited amount of spawning gravel in Grant Creek, the fish will spawn in what
visually appears to be marginal spawning habitat. However, it should be noted that observations
of radio-tagged rainbow in Reach 3 may well have been due to tagged fish taking advantage of
feeding opportunities at those locations.
Feeding Distribution - Mobile detections of rainbow trout can be further scrutinized as to
location by reach (i.e., mainstem, backwater areas and side-channels) and habitat type. Of the
124 detections within Reach 1, all were located within the mainstem, with 23 detections within
pools and 101 detections within riffle habitat. A total of 40 detections occurred within the Reach
2 mainstem, with 19 detections within pool habitat, 13 in riffle habitat and 8 detections within
backwater areas. Within the Reach 3 mainstem, 9 detections were observed in pool habitat and
11 in riffle habitat. Within the Reach 3 Predominant Side Channel, three detections were
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observed in pool habitat and 11 detections within riffle habitat, and three detections were
recorded in the Reach 3 Secondary Channel within pool habitat. Finally, a total of three
detections were observed in the Reach 4 mainstem; with 1 detection in each of pool, riffle and
pocket water habitat.
Furthermore, of the 20 radio-tagged rainbow trout, all 20 were detected at some point within
Reach 1 (either by the fixed telemetry station or during mobile surveys). Fourteen of the twenty
tagged rainbow were also detected in reaches two and three, three in Reach 4, and as discussed
previously, four in Reach 5. The tagged Dolly Varden was not detected at any time after release.
The majority of rainbow trout detections were in Reach 1 and to a lesser extent, the lower portion
of Reach 2. These areas were also where the greatest concentration of sockeye and coho
spawned. Detections of rainbow trout in these areas occurred throughout the tracking period and
toward the end of the study. Near the end of the study period, these areas were the only locations
where tagged rainbow resided. These factors indicate that while it is possible that some rainbow
spawned within this area, fish likely resided within this area to take advantage of feeding
opportunities.
6.1.3 Juvenile Salmonids
Grant Creek Juvenile Abundance and Emigration – There was a total of 4,798 Chinook,
3,165 coho and 46,431 Dolly Varden juveniles that were estimated to have migrated out of Grant
Creek in 2013. These estimates represent Reaches 1-5 upstream of the lower incline plane trap
and only includes parr sized fish. The trap was modified in early July to capture fry-sized fish
(<50 mm), but it was likely too late to capture the majority of fry sized fish (i.e., sockeye,
Chinook and fry) as they likely already migrated out of Grant Creek. For juvenile Chinook,
emigration from Grant Creek peaked in mid-to-late August and again in September. A smaller
peak occurred in May as age-1 fish emigrated from Grant Creek. Juvenile emigration for coho
also peaked in mid-to-late August and in mid-to-late July. Juvenile emigration for Dolly Varden
peaked in July and again in late August-early September.
Use of Reach 5 – Reach 5 of Grant Creek provides some juvenile rearing habitat but it is low in
comparison to Reaches 1-4. The predominance of cascade habitat in Reach 5 likely influences
the amount to juvenile habitat. Minnow trapping in step pool and pool habitat conducted in
Reach 5 of Grant Creek from April through October captured 205 fish. Juvenile rearing habitat
in Reach 5 occurs for Chinook, coho, rainbow trout, Dolly Varden and sculpin sp. Dolly Varden
were the most numerous fish observed. The CPUE for all fish in Reach 5 was low (0.16 fish/hr)
relative to Reaches 1-4 (0.56 fish/hr). Juvenile rearing habitat consisted mostly of step pool
habitat and stream margins during most of the year. Snorkeling conducted in April and May
documented that a few (16 fish) rainbow trout (60-280 mm fork length) rear in Reach 5 during
winter and early spring.
No estimate of abundance in Reach 5 was obtained with the upper incline plane trap. Due to
extreme flow conditions, trapping at this location was terminated. Trap operation resumed on
September 19. Due to extremely high seasonal flows, it is unlikely that any emigrant trapping
method (incline or screw trap) will produce the estimates of interest from Reach 5.
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During the operation of the upper incline plane trap, a total of 172 fish were processed. Of those,
there were 8 Chinook, 1 coho, 7 Dolly Varden, 5 rainbow trout, 19 sculpin and 132 sticklebacks.
Due to the low numbers of species of interest, no fish were marked to assess trap efficiency, and
therefore no estimates of abundance are available.
Use of Reaches 1-4 – Reaches 1-4 of Grant Creek provide the majority of juvenile rearing
habitat in Grant Creek. Minnow trapping from April through October captured 3,468 fish.
Relative abundance of fish caught in minnow traps expressed as both CPUE and proportion of
total catch was highest in Reach 3 followed by Reach 1, Reach 2 and then Reach 4. Reach 3
contained the greatest diversity of habitats with pools and riffles represented in many areas (side
channels, backwater areas and mainstem).
Snorkel surveys in mid-April demonstrated that Chinook, coho, rainbow trout and Dolly Varden
overwinter in Reaches 1-4 on Grant Creek. In winter, most salmonids were observed in pool
habitat available in the mainstem and backwater areas of lower Grant Creek (Reaches 1-4). The
highest fish density (10.5 fish/100 m2) occurred in backwater areas available in Reach 3. Riffle
habitat had the lowest fish densities (0.5 fish/100 m2). Side channel habitat was covered in snow
and ice and was not available for sampling via night time snorkel surveys. Pool habitat
(mainstem and backwater) that occurs in Reaches 1-4 of Grant Creek provides important
overwinter habitat.
In Reaches 1-4 of Grant Creek juvenile Chinook and Dolly Varden were the most numerous fish
captured followed by rainbow trout, coho, sculpins sp. and three spine sticklebacks. Repeated
sampling showed that relative abundance increased from fairly low levels in April and May
representing late winter and early spring stream conditions to much higher levels in late spring,
summer and fall (June-October).
Recently emerged Chinook fry (<50 mm FL) were first noted in minnow traps in June but fry of
this size were also noted in July and August. Juvenile Chinook varied in size from 45-110 mm
fork length. Recently emerged coho fry (<50 mm FL) were first noted in minnow traps in July
but fry of this size were also noted in August, September (1-fish) and October (1-fish). Juvenile
coho varied in size from 42-106 mm FL. For Dolly Varden, the greatest CPUE occurred in June
and remained fairly stable in summer and fall. No Dolly Varden less than 50 mm FL were
captured in minnow traps. Dolly Varden varied in size from 52-165 mm FL. Catch of juvenile
rainbow trout decreased from April to June and remained relatively low into July and August. In
September and October there was a noticeable increase in juvenile rainbow trout. Small rainbow
trout fry (<50 mm FL) were noted in April (1-fish), May (2-fish) and June (1-fish). However,
the majority of small rainbow trout fry were observed in September and October. Rainbow trout
varied in size from 43-146 mm FL.
The highest CPUE in Reaches 1-4 of Grant Creek occurred in side channel areas followed by
backwater areas and then locations within the main stream channel. Side channels occur mostly
in Reaches 1 and 3 and backwater areas occur only in Reaches 2 and 3. For juvenile Chinook
and coho, capture rates were highest in backwater areas while Dolly Varden and rainbow trout
CPUE was the highest in side channels. Mainstem areas dominated by riffle habitat had the
lowest CPUE for juvenile Chinook and coho.
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In Reaches 1-4 of Grant Creek, CPUE for salmonids varied by species and habitat unit type.
Catch rates for juvenile Chinook were nearly equal between pools and glides and the least in
riffles and pocket water. For coho, the catch rate was highest in pools followed by riffles. No
coho were captured in glides. Catch rates for Dolly Varden were highest in glides and runs and
lowest in riffle habitat. Juvenile rainbow trout had the highest catch rates in glides and pocket
water and was the least in pool habitat.
Minnow trapping in lower Grant Creek showed that salmonids were present in all reaches of
Grant Creek with the highest catch rate (0.78 fish/hr.) noted in Reach 3. Reach 3 contained all
channel types (mainstem, backwater and side channels), which increases both channel and
habitat diversity compared to other reaches. The capture rates for salmonids in Reaches 1-4 of
lower Grant Creek indicate that side channel and backwater areas are important juvenile rearing
areas.
6.1.4 Trail Lake Narrows
Adult salmon, rainbow trout and Dolly Varden occur in the Trail Lakes Narrows area. The Trail
Lake Narrows area is an upstream migration corridor for fish destined to spawn in Grant Creek
and all other tributaries of upper Trail Lake. Likewise, this area is also a downstream migration
corridor for salmonid production upstream. Dolly Varden and rainbow trout probably reside in
the area taking advantage of juvenile salmon that migrate through or reside in this area. This
area may also provide spawning and resting areas for adult salmon. Redds in suitable spawning
gravels and sockeye carcasses were found that had not been sampled. Chinook and coho salmon
may spawn in this area as well.
Juvenile Chinook and three-spine sticklebacks were the most numerous fish captured in minnow
traps followed by coho, Dolly Varden, sculpins sp., rainbow trout and sockeye. CPUE for
Chinook and coho was lower in the Trail Lake Narrows than Reaches 1-4 of Grant Creek but
greater than Reach 5. Juvenile Chinook captured in minnow traps in July varied in size from 45-
121 mm FL indicating that both age-0 and age-1 fish were present. Coho varied in size from 45-
97 mm FL. The size range for coho also suggests that age-0 and age-1+ fish were present in the
Trail Lake Narrows. Rainbow trout varied in size from 63-71 mm FL. Dolly Varden varied in
size from 57-184 mm FL with several age classes represented.
6.2 Potential Impacts Associated with the Construction and Operation of a
Grant Creek Dam
This section summarizes potential impacts associated with the construction of the proposed
Project. It should be noted that this summary is not intended to replace a detailed analysis of
expected impacts using integrated Physical Habitat Simulation System (PHABSIM) results at a
later date. It does, however, address perceived flow modification impacts based on operations as
currently proposed for an average water year. Some potential impacts associated with the
Project are not addressed in this section but will be more fully addressed in the DLA. Those
potential impacts are:
• Gravel Recruitment – see Geomorphology Report (KHL 2014b);
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• Temperature Variances – see Water Quality, Temperature and Hydrology Report
(KHL 2014c);
• Outfall Design and Location; and
• Established Minimum Flows, Operational Scenarios and Ramping Rates.
The following assumptions were used to assess potential impacts:
• During the months of December through April, the powerhouse would generally be
operated at a low level; that is, the smallest unit operating at sub-maximum capacity
with a minimum flow condition (unknown level) established in the bypass segment of
Reach 5;
• During the month of May, the lake level would be maintained, the minimum flow
condition would be maintained through Reach 5, and the remainder of Grant Creek
would be primarily operated as run-of-river. Therefore, the amount of flow through
the powerhouse would be equal to the balance of run-of-river flow minus the Reach 5
minimum flow barring unforeseen circumstances such as higher or lower than normal
run-off during this period;
• During June and July, the powerhouse would be operated at peak capacity with
minimum flow conditions through Reach 5; and
• During the period of August through November, the system would be primarily
operated in a run-of-river mode (based on current hydrology); that is, there would be
a minimum flow condition within Reach 5, and the surplus would be ran through the
powerhouse.
It should be noted that some variability still exists and that engineering feasibility work is
currently underway to accurately refine the operating regime and fully specify infrastructural and
operational parameters. This finalized work, after collaboration with stakeholders, will be fully
documented in the Draft and Final LAs.
The operations described above would likely result in lower flows within Reach 5 throughout the
year, with the period of December through April least impacted, and with the period of May
through November lower relative to historic levels depending on minimum flow constraints. In
June and July, once Grant Lake is refilled, flows within Reach 5 will increase but they will again
be lower than historic levels.
Within Reaches 1-4 during the period of December through April, flows are expected to exceed
historic levels, with the exception of December. For the months of May through November,
excluding June and July, flows through Reaches 1-4 will follow run-of-river regimes (historic
levels). In June and July, flows within Reaches 1-4 will decrease relative to historic levels until
Grant Lake is refilled. Once the lake is refilled, flow levels within Grant Creek will return to
run-of-river levels. As an additional note, it is likely that operations, in general, will sustain high
flows for longer periods permitting the more consistent connection of side channel habitats.
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6.2.1 Reach 5
6.2.1.1 Egg Incubation
A decrease in flows during the incubation period would result in more exposure of the channel
bed and bank within Reach 5. The degree to which this will negatively affect salmonid
incubation is unknown. However, given the nature of the canyon reach, which consists of nearly
vertical walls, channel morphology may limit channel bed and bank exposure. Only 1 percent of
the documented spawning that occurred in Grant Creek was in Reach 5.
Project operations are expected to result in decreased sediment transport through Reach 5 due to
lower flows. This will decrease gravel recruitment to the stream including Reaches 1-4 (KHL
2014b). These alterations within Reach 5 may have the potential to negatively impact both
resident and anadromous salmonid species.
6.2.1.2 Adult Spawning
Project operations may have varied impacts to spawning adult salmon and resident fish. With
lower flows, some areas suitable for spawning may no longer be available to spawning
salmonids, with a net loss in suitable spawning habitat. Proposed operations of the Project will
likely result in more stable flows during spawning for both anadromous and resident species,
which will likely have a neutral to slightly positive effect (reduced scour).
6.2.1.3 Juvenile Rearing
Decreased winter flows will likely have no net impact on rearing juveniles within Reach 5. The
canyon reach is primarily cascade (57 percent), step pool (29 percent) and pool (14 percent)
habitat, which provides ample rearing habitat at current winter flow conditions. However, a
decrease in summer flows (and velocities) may increase juvenile habitat during that period of
time. Natural flow conditions during high flow periods result in extremely high velocities within
the canyon reach, resulting in a loss of suitable habitat (lower velocity areas) for juveniles. A
decrease in flows may result in more juvenile habitat relative to current conditions.
6.2.2 Reaches 1-4
Hydrological impacts to Reaches 1 through 4 based on the Project operations described in the
previous section are expected to result in an increase in the annual instream baseline flow (i.e.,
January through April); run-of-river operations in May; decreased flows in June and July until
Grant Lake is refilled, at which time flows would revert to run-of-river; run-of-river flows
August through November; and a slight decrease in flows in December.
These hydraulic conditions may result in the Reach 3 side channels being open throughout the
winter. While current flows within Grant Creek are sufficient to maintain flow within these
channels, they become snowed over. Higher flows may be sufficient to keep that from
occurring.
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The Reach 2 distributary would likely begin to flow later in the summer than it does under
current conditions within an average water year, and would become watered once Grant Lake
refilled during the June-July period. As flows for the period of August through November will
likely be operated in a run-of-river mode, the Reach 2 distributary will dry up as it currently does
in an average water year; that is, sometime in August.
Given the lower flows necessary to maintain flow within the Reach 1 distributary (109 cfs), it
would remain watered during the period of May through November (based on an average water
year).
6.2.2.1 Egg Incubation
The proposed operations would likely have a positive effect on incubating eggs within the
mainstem of Grant Creek for anadromous species; particularly in areas that dewater or have
minimum sub-surface flows during winter months (e.g., margins where fish have spawned, near
the left bank upstream of the weir, etc.). This assumes of course, that baseline flows will be
maintained at a high enough level relative to the natural conditions to keep these areas watered.
To what extent survival will be increased is unknown at this time.
Likewise, increased late fall, winter and early spring baseline flow will likely benefit incubating
eggs within the Reach 3 Predominant and Secondary side channels. Both of these channels
begin to flow as soon as the snow and ice melt, but intra-gravel conditions during winter
incubation are unknown. However, any increased flows during this period would likely improve
incubation survival, assuming that flow is maintained within these channels during the
incubation period. Again, to what extent is unknown.
For the Reach 2 distributary, there will likely be no net change in egg incubation. Under both
current and potential hydrological conditions, that distributary is not watered continuously during
the spawning/incubation period for either resident or anadromous salmonids. As such, there are
no eggs incubating within this distributary.
Likewise, it is unlikely that there would be any net change to the Reach 1 distributary regarding
egg incubation. No spawning was observed in this distributary despite flows occurring
throughout most of the period of spawning observed in Grant Creek. This channel does not have
substrate conducive to salmonid spawning, and therefore no change would be expected.
6.2.2.2 Adult Spawning
During the period of anadromous salmonid spawning within the mainstem of Grant Creek
(August through October), the proposed operating scenario would result in run-of-river
conditions. Therefore, no impact is anticipated. For resident species, which likely spawn in May
and the first half of June, flow will likely be the same as natural conditions in May, and
somewhat less in early June due to the refilling of Grant Lake. As the flow alterations in early
June are relatively minor, no impact would be expected.
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During anadromous and resident spawning in the Reach 3 side channels, flows are expected to be
run-of-river (as described in the preceding paragraph). As such, no benefit or negative impact
would be expected.
During stream surveys in 2013 of the Reach 2 distributary, no spawning of resident or
anadromous species was documented. While this channel will likely be dewatered for a greater
period of time relative to natural conditions, it does not occur during the anadromous spawning
period. And while resident species could spawn within this channel, under natural conditions
redds would become dewatered and developing embryos would die. As such, no change impacts
or benefits would be expected for resident spawning.
6.2.2.3 Juvenile Rearing
Within the mainstem of Grant Creek, under proposed operations flows would increase during
winter months, decrease slightly in June and July and follow run-of-river flows in May and
August through November. In winter, modest increases in flow may result in an increase of
juvenile over-winter rearing habitat. In general, weighted usable area (WUA) for juveniles
increases at the lower end of the flow regime in Grant Creek with increases in flow (KHL
2014a). During June and July when flows are somewhat decreased, it may result in more
juvenile habitat being maintained. That is, under high flow conditions, some juvenile habitat
becomes more turbulent with greater velocity, which decreases available juvenile habitat. It
should be noted however, that when flows increase dramatically, the margins of Grant Creek
begin to flood, which provide excellent habitat for juvenile salmonids, especially young of the
year. Given these scenarios, it is not possible to determine what impact may be expected without
further IFIM analysis. That is, general trends in WUA for fry tend to increase with flow in some
areas while for other areas WUA decreases.
As discussed above, it is possible that higher winter flows may result in the Reach 3 side
channels being open during winter months. Should this occur, it would make a large amount of
over winter habitat available to rearing juveniles. Given the quality of these side channels, this
would certainly increase juvenile overwinter habitat. During the spring, summer and fall
periods, the available habitat would not likely change much, if at all. Therefore, no impact or
benefit would be expected.
For the Reach 2 distributary, the altered flow regimes would likely result in that channel being
dewatered for a greater period of time relative to natural conditions, and would likely occur
during the June/July period. This alteration would result in the loss of a substantial amount of
juvenile rearing habitat that is currently utilized by both anadromous and resident species. To
what extent this alteration would have on juvenile fish is unknown.
The Reach 1 distributary should remain watered similarly under the altered conditions relative to
natural conditions. As such, no impact or benefit would be anticipated.
6.2.3 Global Issues
The discussion presented in the preceding sections is based on one possible operating scenario.
Issues and perceived impacts may change depending on refinements to that scenario. As that
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 126 June 2014
scenario is refined, aquatic impacts will be refined accordingly and will be further detailed in the
DLA. While only mentioned briefly in the previous section, minimizing impacts associated with
ramping rates, temperature variances and gravel recruitment should be considered during the
Project design phase and when developing Project operations. Establishment of minimum flow
requirements, both in Reach 5 and lower Grant Creek, as well as outfall design should be
considered as the Project is more fully developed. Ongoing efforts in the Aquatic Resources
Working Group will help refine potential impacts, which will assist in development of PM&E
measures and preparation of the DLA.
In this section there is a brief discussion of some aspects of Project operation that may be
addressed in the DLA as operational scenarios are fully developed. For example, the rate in
which Project flows are ramped up, and especially decreased can result in stranding and
mortality of juvenile salmonids. Stranding has the potential to isolate fish in areas of the river
channel where predators or increased water temperatures can cause mortality. Typically, smaller
juvenile fish are most the vulnerable to potential stranding because of their habitat preference
and poor swimming ability. The incidence of stranding for juvenile fish is affected by river
channel configuration, time of day, substrate type and water temperature among other factors.
Seasonal temperature variances may occur in winter and early spring as warmer water from
Grant Lake is bypassed through the project downstream to Grant Creek (KHL 2014c).
Temperature changes as small as 2°C can affect the rate of egg development during the
incubation period, thus effecting time of hatching and emergence (Scannell 1992). Accelerated
development leading to early emergence can have several disadvantages such as decreased
foraging ability or emergence before suitable prey species are available and increased
susceptibility to predation (Scannell 1992).
A reduction in gravel recruitment to Grant Creek is likely to diminish the quantity and quality of
spawning habitat in Grant Creek (KHL 2014b). As discussed in KHL (201b), these impacts are
likely to occur incrementally over time, and are typically measured in years and decades as the
result of flow bypassed around the canyon reach. The canyon area of Grant Creek (Reaches 5
and 6) is the primary source of sediment recruitment.
7 VARIANCES FROM FERC-APPROVED STUDY PLAN AND PROPOSED
MODIFICATIONS
In this section, variances that occurred from the FERC-approved study plan are discussed.
The upper incline trap had to be taken out of operation because of dangerous working conditions
and potential loss/destruction of equipment. Due to extremely high seasonal flows, it is unlikely
that any emigrant trapping method (incline or screw trap) will produce the estimates of interest
from Reach 5.
For the lower incline plane trap, the size of mesh used on the incline plane and more importantly
the live box did not allow for capture and retention of small age-0 fish (<50 mm). No estimate of
fry size fish is provided. The estimate provided in this report is largely for parr and smolt sized
emigrants from Grant Creek. Modifications to the trap were completed in mid-July to improve
trap efficiency but this was probably too late for most of the smaller age-0 emigrants.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
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FERC No. 13212 127 June 2014
The weir was placed in Grant Creek in late May, which may have been too late to assess total
abundance and run timing for adult rainbow trout. The location of the weir may have also been
an issue. The weir was placed across a stream channel with an undercut bank that likely allowed
rainbow trout to move both upstream and downstream of the weir. In July, when the weir was
inspected, measures were taken to close the gap with additional pickets. Unfortunately, this was
too late for the rainbow trout migration period. As a result, angling was used to secure rainbow
trout for tagging. Most of the fish captured and tagged from angling occurred in July, which is
likely past the spawning period. As such, it was not possible to identify areas of rainbow trout
spawning within Grant Creek. Natural high flows during the upstream migration of adult
rainbow trout make accurate data collection related to this component of Grant Creek research an
annual issue.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
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FERC No. 13212 128 June 2014
8 REFERENCES
AEIDC (Arctic Environmental Information and Data Center). 1983. Summary of environmental
knowledge of the proposed Grant Lake hydroelectric project area. Final Report submitted
to Ebasco Services, Inc., Redmond, Washington, University of Alaska, Anchorage,
Alaska.
Bue, B.G., S.M. Fried, S. Sharr, D.G. Sharp, J.A. Wilcock, and H.J. Geiger. 1998. Estimating
salmon escapement using area-under-the-curve, aerial observer efficiency, and stream-
life estimates: the Prince William Sound example. North Pacific Anadromous Fisheries
Commission. Bulletin. No. 1:240-250.
Burgner, R. L., 1991. Life history of sockeye salmon (Oncorhynchus nerka). Pages 4-117 in C.
Groot, and L. Margolis, editors. Pacific salmon life histories. University of British
Columbia Press. Vancouver, B.C., Canada.
Ebasco (Ebasco Services, Inc.). 1984. Grant Lake Hydroelectric Project Detailed Feasibility
Analysis. Volume 2. Environmental Report. Rep. from Ebasco Services Incorporated,
Bellevue, Washington.
English, K.K., R.C. Bocking, and J.R. Irvine. 1992. A robust procedure for estimating salmon
escapement based on the area-under-the-curve method. Canadian Journal of Fisheries
and Aquatic Sciences 49:1982-1989.
Envirosphere. 1987. Instream flow and habitat analysis Grant Lake hydroelectric project.
Prepared for Kenai Hydro, Inc.
Evans, S. D., and J. R. Stevenson. 2012. Optimization of radio telemetry receiving systems.
Pages 139-162 in N. S. Adams, J. W. Beeman, and J. H. Eiler, editors. Telemetry
techniques: a user guide for fisheries research. American Fisheries Society, Bethesda,
Maryland.
Hahn, P. K. J., R. E. Bailey, and A. Ritchie. 2007. Beach seining. Pages 267-324 in D. H.
Johnson, B. M. Shrier, J. S. O’Neal, J. A. Knutzen, X. Augerot, T. A. O’Neil, and T. N.
Pearsons. Salmonid field protocols handbook: techniques for assessing status and trends
in salmon and trout populations. American Fisheries Society, Bethesda, Maryland.
Hayes, S. R., and J. J. Hasbrouck. 1996. Stock assessment of rainbow trout in the Upper Kenai
River, Alaska, in 1995. Anchorage, AK, Alaska Department of Fish and Game, Fishery
Data Series No. 96-43.
HDR. 2009a. Technical Memorandum - Review of 1986-1987 Grant Lake FERC application
documents for instream flow considerations. Prepared for Grant Lake/Falls Creek
Hydroelectric Technical Working Group.
HDR (HDR Alaska Inc.) 2009b. Grant Lake Hydroelectric Project Environmental Baseline
Studies Report, 2009 Draft. Prepared for: Kenai Hydro, LLC.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 129 June 2014
Johnson, J., and M. Daigneault. 2008. Catalogue of waters important for spawning, rearing, or
migration of anadromous fishes – Southeastern Region, Effective June 2, 2008. Alaska
Department of Fish and Game, Special Publication No. 08-06, Anchorage, AK.
Johnson, J. and K. Klein. 2009. Catalog of waters important for spawning, rearing, or migration
of anadromous fishes – Southcentral Region, Effective June 1, 2009. Alaska Department
of Fish and Game, Special Publication No. 09-03, Anchorage, AK.
Kenai Hydro, Inc. 1987a. Grant Lake hydroelectric project additional information.
Kenai Hydro, Inc. 1987b. Grant Lake hydroelectric project FERC No. 7633-002 additional
information final report with agency license terms and conditions for selected alternative
I and power contract information.
KHL (Kenai Hydro, LLC). 2009. Pre-Application Document Grant Lake/Grant Creek and Falls
Creek Project (FERC No. 13211 and 13212.
KHL. 2013. Grant Lake Project (FERC No 13212), Aquatic Resources Final Study Plan.
Prepared by BioAnalysts Inc. for Kenai Hydro, LLC. March 2013.
KHL. 2014a. Grant Lake Hydroelectric Project (FERC No. 13212). Aquatic Resources Study –
Grant Creek Aquatic Habitat Mapping and Instream Flow Study, Final Report. Prepared
by McMillen LLC for Kenai Hydro, LLC. June 2014.
KHL. 2014b. Grant Lake Hydroelectric Project (FERC No. 13212), Water Resources –
Geomorphology, Final Report. Prepared for Kenai Hydro, LLC. Prepared by Element
Solutions for Kenai Hydro, LLC. June 2014.
KHL. 2014c. Grant Lake Hydroelectric Project (FERC No. 13212), Water Resources Study –
Water Quality, Temperature and Hydrology, Final Report. Prepared by McMillen, LLC
for Kenai Hydro, LLC. June 2014.
Marcuson, P. 1989. Coho salmon fry stocking in Grant Lake, Alaska. Prepared for: U.S. Forest
Service, Seward Ranger District, Chugach National Forest.
McMahon, T. E. 1983. Habitat suitability index models: coho salmon. U.S. Dept. Int., Fish
Wildl. Servo FWS/OBS-82/10.49. 29 pp.
Raleigh, R. F., T. Hickman, R. C. Solomon, and P. C. Nelson. 1984. Habitat suitability
information: Rainbow trout. U.S. Fish Wildlife Service. FWS/OBS-82/10.60. 64 pp.
Raleigh, R. F., W. J. Miller, and P. C. Nelson. 1986. Habitat suitability index models and
instream flow suitability curves: Chinook salmon. U.S.
Scannell, P. K. W. 1992. Influence of temperature on freshwater fishes: A literature review with
emphasis on species in Alaska. Juneau, AK, Alaska Department of Fish and Game.
Technical Report no. 91-1.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 130 June 2014
Sisson, D. 1984. Fishing the Kenai Peninsula. Alaska Fieldbooks Co.
Skalski, J. R., and R. L. Townsend. 2014. Estimating salmonid outmigrant abundance at Grant
Creek. Report prepared for BioAnalysts, Inc., Redmond, WA.
USFWS (U.S. Fish and Wildlife Service). 1961. Ptarmigan and Grant Lakes and Falls Creek,
Kenai Peninsula, Alaska, progress report on the fish and wildlife resources. Department
of the Interior. Juneau, Alaska.
Volkhardt, G. C., S. L. Johnson, B. A. Miller, T. E. Nickelson, and D. E. Seiler. 2007. Rotary
screw traps and inclined plane screen traps. Pages 235-266 in D. H. Johnson, B. M.
Shrier, J. S. O’Neal, J. A. Knutzen, X. Augerot, T. A. O’Neil, and T. N. Pearsons.
Salmonid field protocols handbook: techniques for assessing status and trends in salmon
and trout populations. American Fisheries Society, Bethesda, Maryland.
FINAL REPORT AQUATIC RESOURCES – FISHERIES ASSESSMENT
Grant Lake Hydroelectric Project Kenai Hydro, LLC
FERC No. 13212 June 2014
Appendix 1: Estimating Salmonid Outmigrant Abundance at
Grant Creek
Estimating Salmonid Outmigrant
A bundance at Grant Creek
To:
John Stevenson
BioAnalysts, Inc.
16541 Redmond Way, #339
Redmond, Washington 98052
From:
John R. Skalski
Richard L. Townsend
Columbia Basin Research
School of Aquatic and Fishery Sciences
University of Washington
1325 Fourth Avenue, Suite 1820
Seattle, Washington 98101-2509
13 February 2014
P a g e | 1
Introduction
The purpose of this analysis is to estimate the outmigrant abundance of salmonid species at
Grant Creek in 2013. An incline plane trap was used to obtain a daily index count, which could then be
adjusted for trap collection efficiency. This analysis estimates outmigrant abundance of Chinook
salmon, coho salmon, and Dolly Varden over the outmigration season. The estimation process accounts
for missing index data and provides standard error calculations. We also report the number of rainbow
trout and sockeye captured at the incline plane trap but no estimates of their abundance are provided.
Sample sizes were too small for reliable estimates of rainbow trout and sockeye salmon.
Study Design
A single incline plane trap was located downstream from an overflow channel along Grant Creek
(Figure 1). That trap provided daily or near daily index counts of captured fish by species. Above the
trap and overflow channel, periodic calibration releases were performed (Figure 1) to estimate the trap
efficiency of the include lane. The calibration releases actually estimate the joint probability of a fish
staying in Grant Creek and being detected (i.e., captured) by the incline plane trap. Similarly, the fish at
the trap also represent fish that stayed in Grant Creek and were captured at the trap. Hence, the
migrant abundance estimated is the number of juveniles present at the location of the efficiency
releases. The overflow channel on Grant Creek became active at a flow ≥426 cfs and potentially
directed fish past the incline plane trap during the three periods 30 May-3 August, 10-14 August, and 7-
15 September.
Statistical Methods
Season-Wide Estimator
The season-wide estimator of total juvenile abundance ()*N is the sum of estimated abundance
when the index counts at the incline plane trap are present ()N% and during periods when such data are
missing ()ˆjN , i.e.,
*
1
ˆk
j
j
N N N
=
=+∑%
where k = number of missing trap index count events during the season.
Specifically, the estimate of total migrant abundance can be written as follows:
P a g e | 2
Figure 1. Schematic of migrant abundance ( )
ˆN estimation process including trap efficiency releases
(R), downstream recovery numbers (r), the probability of capture at the trap (p), probability a migrant
remains in the river ( )
, and the number of fish caught in the trap (n). As such, ( )
E n N p=and
( )
E r R p=, permitting abundance estimation as ( )
ˆN n r R=.
P a g e | 3
2 1 1 2
*
1
4
ji ji ji ji
jk
j
n n n n dnNrr
R R
- - + +
=
+ + += +
∑ (0)
where
n = total index count at incline plane during periods of operations,
R = total number of fish released during trap efficiency trials,
r = number of R recaptured at trap,
1jin- = number of index fish caught one day prior to the jth data gap (j = 1, …, k),
2jin- = number of index fish caught two days prior to the jth data gap (j = 1, …, k),
1jin+ = number of index fish caught one day after the jth data gap (j = 1, …, k),
2jin+ = number of index fish caught two days after the jth data gap (j = 1, …, k),
K = number of data gaps in incline plane index counts.
( )( )
*
1
ˆVar Var Var
k
j
j
N N N
=
= + ∑% (0)
Estimator (1) and variance (2) were stratified for high and low flow seasons for two fish stocks where
detection efficiencies were significantly different between periods.
In the case where there are missing index counts, the sampling process has three sources of
variance as follows:
1. Binomial sampling ()Bin ,n N p.
2. Estimator of the missing value by ˆn.
3. Estimator of the trap efficiency using the efficiency releases.
The overall variance during these missing data events can be calculated in stages as follows:
( )1 2 3 1 2 3 1 2 3
ˆˆˆˆVar Var 1,2 Var 1,2 Var 1,2ˆˆˆj
n n nN E E E E E Epp p
=++
where 1, 2, and 3 refer to the sampling stages listed above. Then
P a g e | 4
( )
()
( )
( )( ) ( )()
( )( )( )( )( )()
( )
( )( )
2
1 2 1 2 1 2 4
2
1 1 12 4
2
1224
2
ˆ ˆVarˆˆˆVar Var 1 Var 1
ˆVar1ˆˆ ˆVar Var Var
ˆ ˆ1 Var Var ˆVar
ˆ1 Var VaˆVar
j
j
j
j
n pnnNE E E Epp p
pnE n E n E np p p
N p p n p n E np p p
N p nNp p
++
=+++
-
=+ ++
-
= + +
( )( ) ( )()()2 2
4
ˆr ˆVar 1j j
p n N p p N pp+- + (0)
where
2 1 1 2ˆ4
ji ji ji ji
j
n n n nn d- - + +++ +=
= estimate of missing index data,
d = duration of data gap,
( )
2 2
ˆVar 4
ns dn=,
ˆrpR= = estimate of trap efficiency,
( )
( )
1ˆˆ1ˆVar
r r
p p R RpR R
- - = =, and
ˆˆ
ˆ
j
j
nNp= = abundance estimate for jth period.
In the case where the index count (n) is available, the variance of the estimate of fish abundance
()N% is estimated by
ˆ
nNp=%
and has two sources of variance:
1. Binomial sampling ()Bin jn N p.
2. Estimate of the trap efficiency using the efficiency releases.
The overall variance during these time period can be calculated in stages as follows:
P a g e | 5
( )
( )
( )( )( ) ( )
( )( )( )
( )
2
2
4
2
2 4
2 2
4
Var Var ˆ
Var Varˆˆ
1VarVarˆ
ˆVarVar
ˆ1 Var Var
ˆ1 Var 1
1 1
n p n p
n n
n n
nNp
n nE n E npp
n E np p
pnE np p
Np p p n E np p
N p p Np p N pp p
N p p
p
=
=+
+
= +
-= ++
-= +-+
-=+
%
( )( )
( )
( )( )( )
2 2
4
2 2
2
1
1 1 1Var
p Np p N pp R
N p N p N pNp p R pR
-- +
- - -
=+ +% (4)
where
ˆ,
.
rpR
nRNr
=
=%
Test of Homogeneous Trap Efficiency
A test of homogeneous trap efficiency between high and low flow periods was performed using
a 2 × 2 contingency table of the form
High Low
Caught 1r 2r
Not caught 1 1
R r- 2 2
R r-
A test of homogeneity was based on a chi-square test of 1 degree of freedom.
P a g e | 6
Results
Raw counts of the total number of individuals captured at the incline trap per species ranged
from 36 to 969 (Table 1). Efficiency release sizes were too small to convert counts to absolute
abundance for rainbow trout and sockeye salmon. Tests of homogeneous trap efficiency during low and
high river flow conditions found no difference for Chinook salmon and coho salmon but a flow effect for
Dolly Varden (Table 2). Hence, a single estimate of trap collection efficiency was used in the estimation
of outmigration abundance for Chinook salmon and coho salmon, while two seasonal values were used
for Dolly Varden (Table 2).
The incline trap study estimated juvenile abundance in Grant Creek at the site of the calibration
(i.e., trap efficiency) releases. For Chinook salmon, total outmigration was estimated to be ˆN = 4,797.7
(95% confidence interval = (3,615.4–5,980.0)). For coho salmon, total outmigration was estimated to be
ˆN = 3,164.9 (95% CI = (2,094.3– 4,235.5)). The seasonally stratified estimate of total outmigration
abundance for Dolly Varden was estimated to be 46,431.2 (95% CI = (-4,570.2–97,432.6)) (Table 2).
Two factors contributed to high standard errors associated with the total abundance estimates.
The first was the highly variable daily count on either side of the three “data gaps” observed during the
study. Though only 2- 4 days long (a total of 10 days, approximately 7% of the study), these gaps
contributed abundance estimates with large associated variance. The greater issue was the low
detection efficiencies, which especially affected the Dolly Varden abundance estimate, as its expansion
factor during the low flow period was approximately 12 times that of the other species at the trap.
Table 1. Number of juvenile salmonids caught by species at the incline plane trap during the 2013
outmigration at Grant Creek.
Species Count (n)
Chinook salmon 577
Coho salmon 360
Dolly Varden 969
Rainbow trout 36
Sockeye salmon 22
P a g e | 7 Table 2. Summary of trap efficiency release numbers (R) and number of smolts recaptured (r) under high and low flow conditions for three species of salmonids. Chi-square tests of homogeneity (df = 1) were performed comparing low and high flow recovery information. Species Low Flow Condition High Flow Condition Trap Efficiency Test for Trap Efficiency Difference Release Recapture Release Recapture Low High Combined χ2* p CK 380 45 68 10 0.118 0.147 0.123 0.2136 0.6440 CO 169 19 110 13 0.112 0.118 0.115 0.0000 1.0000 DV 248 2 571 41 0.008 0.072 12.8685 0.0003 *Estimated with Yates continuity correction
P a g e | 8
Table 3. Estimates of total outmigrant abundance through Grant Creek. Estimates separated by periods
with daily index counts and with gaps in the index count. In the case of Dolly Varden, the estimation
was also stratified by low- and high-flow trap efficiency periods.
Chinook Coho
Dolly Varden
Low Flow High Flow Total
Observed n 577 360 296 673
Est. N 4,699.9 3,138.8 36,704.0 9,372.8 46,076.8
Var N 361,252.8 297,453.8 674,913,300.0 2,112,700.0 677,026,000.0
SE N 601.0 545.4 25,979.1 1,453.5 26,019.7
Gap n 12.0 3.0 0.5 21.0
Est N 97.7 26.2 62.0 292.5 354.5
Var N 2,538.3 929.5 20,981.3 50,786.1 71,767.4
SE N 50.4 30.5 144.8 225.4 267.9
Total
Est N 4,797.7 3,164.9 36,766.0 9,665.2 46,431.2
Var N 363,791.1 298,383.3 674,934,281.3 2,163,486.1 677,097,767.4
SE N 603.2 546.2 25,979.5 1,470.9 26,021.1