HomeMy WebLinkAbout170515r-KnutsonCrFishSurveyReportpolarconsult alaska, inc.
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F ISHERIES S URVEY R EPORT
170515R-FISHSURVEYREPORT.DOC
DATE: May 15, 2017
TO: Tracy Hansen, Permit Coordinator, ADFG Division of Sport Fish
FROM: Joel Groves, Polarconsult
SUBJECT: Late‐Winter Fisheries Survey of Knutson Creek Associated with Potential
Hydroelectric Development for Pedro Bay, Alaska
CC: John Baalke, Pedro Bay Village Council Administrator
Kate Harper & Josh Brekken, ADFG Habitat Biologists (Project Permit Adjudicators)
1.0 INTRODUCTION AND BACKGROUND
The Pedro Bay Village Council (PBVC) operates the electric utility serving the village of Pedro
Bay, Alaska. PBVC is in the design and permitting phase of developing a run‐of‐river
hydroelectric project on Knutson Creek that will meet most of the electrical needs of the village.
As part of the design and permitting process, Polarconsult mobilized to Knutson Creek in late
winter 2017 (March 28 through 31) to perform a resident fish survey of the upper portion of
the proposed bypass reach of Knutson Creek.
Prior surveys at Knutson Creek documented presence of adult sockeye salmon below, in and
above the bypass reach and also an abundance of resident Dolly Varden (DV, Salvelinus malma)
throughout the bypass reach. Sculpin (Cotus sp.) have also been documented in the bypass
reach (ABC 2012, ADFG 2012, ADFG 2016, HDR 2011).
2.0 OBJECTIVES
The objectives of this study were to determine resident fish presence by species and their
distribution in the upper portion (river mile (RM) 2.03 to RM 2.59) of the proposed bypass
reach of Knutson Creek (RM 1.12 to 2.59, Map 1) during late winter low flows.
3.0 METHODS
The survey was timed to coincide with the late winter low flow period to assess distribution
during this season and flow regime.
Trapping was conducted in accordance with Alaska Department of Fish and Game (ADFG)
collection permit SF2017‐0114. Field assistance was provided by Gary Paulus (Polarconsult) and
Winn Knighton (PBVC).
Four standard minnow traps were deployed in the upper bypass reach of Knutson Creek. Two
were deployed in the main stem, one in a main stem side channel, and one in a minor tributary.
Average fishing time per trap was 18.1 hours (range 17.8 to 18.4 hours, Table 1). Trap bait
consisted of Power Bait pellets inserted into perforated 35mm film canisters. One canister was
inserted into each minnow trap and filled with water during trap deployment. All traps were
weighted with one cobble and secured to available brush or rocks with line. Traps were marked
with flagging and labeled, and trap locations were documented by GPS and photographed.
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Table 1: Summary of Trap Locations and Results
4.0 RESULTS
The survey was successfully timed to coincide with the annual low flow. Main stem flow was
measured at 12.2 cubic feet per second (cfs) at the upper gauging station (RM 2.09) on March
29th and main stem water temperature was +32.28F. Main stem, side channel, and tributary
waters all had excellent clarity. Main stem flow and water temperature measured at the lower
gauging station (RM 2.03) remained constant through April 4th, when daily fluctuations in both
parameters began due to the onset of warmer weather.
No fish were caught in any of the deployed traps.
5.0 DISCUSSION
This survey focused on the upper bypass reach (RM 2.03 to RM 2.59), which had not been
previously surveyed during the winter season. It slightly overlapped with ADFG’s April 2016
survey reach (RM 1.3 to RM 2.15).
The upper bypass reach would experience the greatest relative reduction in late winter flow
from the hydro diversion. The bypass reach receives flow from numerous minor tributaries
downstream of the diversion site. These tributary inflows provide a source of water in Knutson
Creek that is independent of main stem flow at the diversion site. Immediately downstream of
the diversion site (RM 2.59), tributary inflow is zero. At the downstream end of the upper
bypass reach (RM 2.09), tributary inflow is 12% of total main stem flow at the diversion site. At
the downstream end of the full bypass reach (RM 1.12), tributary inflow is 18% of total main
stem flow at the diversion site.1
Ice coverage on Knutson Creek was 100% at the time of the survey, with no open leads in the
main stem or side channels. The thinnest ice on the main stem, 6 to 12 inches thick, was
typically found over the thalweg. Ice along the lateral margins of the main stem commonly
consisted of multiple tiered ice shelves each 1+ feet thick.
Traps were deployed in a variety of prospective wintering habitats for resident fish. Trap 1 was
in a perched lateral pool off the main stem with a depth of 12 inches; Trap 2 was in a minor
tributary/main stem side channel habitat with a depth of 9 inches; Trap 3 was in a shallow main
1 Tributary flows are estimated based on the ratio of main stem subbasin and tributary subbasin areas. Subbasin
areas are provided in Table E‐1 of the project feasibility study (Polarconsult 2013).
Trap Latitude
(D.ddddd)
Longitude
(D.ddddd)
River
Mile
Time Deployed
and Recovered
Time
Fished
(hours)
Habitat Description Catch
1 59.82611 154.10875 2.59 3/30/2017 17:21
3/31/2017 11:45 18.40 Side channel of main
stem (spawning site 4). 0
2 59.82349 154.11121 2.38 3/30/2017 18:30
3/31/2017 12:15 17.75
Lower reach of main
stem side channel/minor
tributary.
0
3 59.81957 154.11433 2.10 3/30/2017 18:50
3/31/2017 12:45 17.92 Shallow pool in main
stem thalweg. 0
4 59.81894 154.11497 2.03 3/30/2017 19:08
3/31/2017 13:21 18.22 Near left bank at braided
reach of main stem. 0
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stem thalweg pool with a depth of 12 inches; and Trap 4 was in a main stem lateral channel
with a depth of 12 inches immediately adjacent to a pool approximately 36 inches deep.
Prior surveys documented an abundance of resident DV in Knutson Creek, and there is no
reason to think these fish are not still present and wintering in Knutson Creek. No flaws in
survey methodology are apparent, so the lack of catch is attributed to their seasonal non‐
presence in or proximate to the habitats in the reach surveyed.
Based on the catch results it is apparent that the upper project reach is not extensively if at all
used for over‐wintering of resident DV. The likelihood is that resident DV descend to lower
reaches of Knutson Creek where flow and other habitat conditions are presumably more
favorable for survival and over‐wintering. It is noted that a prior survey by ADFG in April 2016
found resident fish throughout that surveyed reach (RM 1.3 to RM 2.15) with the highest
densities towards the downstream end (ADFG 2016). This effect would expectedly have been
more pronounced during the current survey than during the April 2016 survey as winter
conditions (water stage and flow, air and water temperature, and ice cover) at the time of this
survey were all more distinct or harsher than during the April 2016 survey.
There is the possibility that resident fish were aggregated in deep thalweg pools, which would
be some of the safest refuge areas during the late winter low flow period. Trap sites 1 and 2
may have had poor physical connectivity to main stem thalweg pools, physically preventing fish
from reaching these traps even if they sensed the bait. However, trap sites 3 and 4 expectedly
had good connectivity to main stem pools, and since it is well established that baited minnow
traps are effective at capturing resident DV, if fish were present in the deep thalweg pools traps
3 and 4 should have produced some catch. Since they did not, it is reasonable to presume that
the deep thalweg pools in the survey reach were not being used as DV over‐wintering habitat,
at least to any measurable degree.
6.0 LITERATURE CITED
ABC 2012. Alaska Biological Consulting. September 2012. A Fisheries Survey of Upper
Knutson Creek Associated with Potential Hydroelectric Development for
Pedro Bay, Alaska. Principal Investigator: Mr. Bruce Barrett. Lakeside, MT.
ADFG 2012. Alaska Department of Fish and Game. October 12, 2012. Nomination
Form, Anadromous Waters Catalog, Waterway 324‐10‐10150‐2301
(Knutson Creek). (Surveyed August 15, 2012). Principal Investigator: Raye
Ann Neustel. Anchorage, AK.
ADFG 2016. Alaska Department of Fish and Game. April 18, 2016. Memorandum,
Knutson Creek Site Visit (April 5, 2016). Principal Investigator: Josh
Brekken, Habitat Biologist. Anchorage, AK.
HDR 2011. HDR, Inc. August 5, 2011. Pebble Project Environmental Baseline
Document 2004 through 2008. Chapter 15. Fish and Aquatic Invertebrates,
Bristol Bay Drainages. Anchorage, AK.
Polarconsult 2013. Polarconsult Alaska, Inc. November 2013. Knutson Creek Hydroelectric
Feasibility Study, Final Report. Anchorage, AK.
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Map 1: Knutson Creek and Survey Sites
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Photograph 1:
Trap Site #1 looking upstream.
Trap site in perched pool at end
of main stem side channel
Main stem Knutson Creek
Photograph 2:
Trap Site #2 before trap
deployment looking downstream.
Trap site prior to ice
removal.
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Photograph 3:
Trap Site #3 looking towards right
bank.
Trap 3 under ice shelf.
(direction of flow)
Photograph 4:
Trap Site #4 looking down. Large
boulders at right of photograph
form the main stem left bank.
(direction of flow)
Deep pool
Trap #4