HomeMy WebLinkAboutKnutson Creek Logger Deployment 11_7_17MEMORANDUM State of Alaska
Department of Fish and Game
Division of Habitat
TO: Ron Benkert DATE: November 10, 2017
Regional Supervisor
Central Region Office SUBJECT: Knutson Creek
HOBO Logger Deployment
November 7, 2017
FROM: Josh Brekken PHONE NO: (907) 267-2113
Habitat Biologist
On Tuesday, November 7, 2017, Jacob Cunha and I flew to Pedro Bay to deploy HOBO
temperature loggers into the stream substrate of Knutson Creek. A hydroelectric project on
Knutson Creek has been proposed and is in the planning stages. The temperature loggers should
provide information regarding the winter low-flow conditions as well as potential salmon
spawning viability within the reach of stream proposed for water diversion as part of the
hydroelectric project. The loggers will be retrieved in the spring before water levels become too
high for safe retrieval.
We were joined by Wynn Knighton (Pedro Bay Corporation) in Pedro Bay and traveled to the
site on four-wheelers and on foot. The logger deployment site is located about 1.8 miles
upstream from the mouth of the river (see Figures 1 and 2) where more than 20 sockeye salmon
were observed spawning during a project related fish survey. We arrived in Pedro Bay around
11:00 am and during our site visit the air temperature was about 34ºF, the skies were overcast,
there was no wind, and the river level was approximately 120 cfs.
The deployment site is located at the outlet of a small canyon just downstream of a sharp bend in
the river where the channel is confined. The channel becomes unconfined a short distance
downstream from the site. The stream habitat at the deployment site is pool with a cascade
immediately upstream and a long riffle downstream. The channel is about 50 feet wide at this
location and the profile is uniform with the thalweg in the middle of the channel. The substrate at
the site is a mix of gravel (40%), cobble (50%), and sand (10%). The loggers were deployed in
gravels between the thalweg and river-left streambank in water depths that ranged from 0.3 to
0.8 meters. I would expect a high degree of hyporheic exchange in this reach of the stream based
on the valley constriction and channel morphology. The thalweg water depth at the outlet control
of the pool where the loggers were placed was 0.7 meters.
To deploy the loggers, the technique described in Zimmerman and Finn (2012) was followed.
Using a steel driving rod and sledge hammer, a steel pipe was driven about 1 foot into the stream
substrate. The driving rod was removed and a HOBO temperature logger with an 18-inch tether
was inserted down into the pipe using a piece of PVC that held the logger and tether in position
while the pipe was slowly removed from the streambed. The result was a temperature logger
Knutson Creek Site Visit, November 7, 2017 2 November 10, 2017
placed 10 to 12 inches below the stream substrate with 6 inches of the tether remaining above the
substrate for retrieval. After placing 7 loggers in the substrate, the site was marked with flagging
and rebar stakes were pounded into the streambank at the upstream and downstream extents of
the loggers. The distance from the rebar stakes to each logger was measured and GPS points
were recorded to assist with retrieval in the spring. The loggers were placed at and between
59.817809ºN/154.117394ºW and 59.817714ºN/154.117303ºW.
All gear and equipment, except for 7 HOBO loggers, 2 rebar stakes, and some flagging was
packed back to Pedro Bay where we awaited our return flight to Anchorage. We departed around
4:45 pm and arrived in Anchorage around 6:45 pm.
Photograph 1. Logger deployment site.
Knutson Creek Site Visit, November 7, 2017 3 November 10, 2017
Photograph 2. Upstream of logger deployment site.
Photograph 3. Downstream view from logger deployment site.
Knutson Creek Site Visit, November 7, 2017 4 November 10, 2017
Photograph 4. Driving pipe into substrate.
Photograph 5. Underwater view of logger system deployed in substrate.
Knutson Creek Site Visit, November 7, 2017 5 November 10, 2017
Photograph 6. Underwater view of loggers in substrate.
Knutson Creek Site Visit, November 7, 2017 6 November 10, 2017
Photograph 7. Overview of deployment site with logger locations marked.
Reference:
Zimmerman, C. E. and Finn, J. E. 2012. A Simple Method for In Situ Monitoring of Water Temperature in
Substrates Used by Spawning Salmonids. U.S. Geological Survey Alaska Science Center. Journal of Fish and
Wildlife Management.
Email cc:
A. Ott, ADF&G
T. Elison, ADF&G
J. Dye, ADF&G
K. Harper, ADF&G
J. Cunha, ADF&G
J. Groves, PolarConsult
Temperature Loggers
Figure 1Knutson Creek Temperature Logger Deployment
1 0 10.5 Kilomete rs
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Temperature Loggers
Figure 2Knutson Creek Temperature Logger Deployment
0.1 0 0.10.05 Kilomete rs
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