WSP05499

• File Number: 8200.766
• Description: Gunnison River General
• State: CO
• Basin: Gunnison
• Water Division: 4
• Date: 4/1/1997
• Author: Mueller and Hiebert
• Title: Assessment of Kokanee Salmon Transport through Blue Mesa Powerplant - Colorado - During the Spring and Summer of 1994-1996
• Water Supply Pro - Doc Type: Report/Study

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day, fish were found deeper, but they were also more widely
distributed throughout the water column than during the night
(Appendix D, Part 2). During the day, over 30 percent of the fish
were located at depths greater than 30 meters compared to less that 7
percent at night. This distribution in the higher velocity areas may
help explain the higher entrainment rates experienced during daylight
hours. Fish densities near the dam were generally found to be below
reservoir averages. In 1995, densities were measured at 208-246
fish/ha compared to a reservoir average of near 350 fish/ha. However,
a separate analysis of fish <100 cm indicated densities of these sized
fish were highest near the dam and low portions of the reservoir
(Appendix D, Part 2).

During the 1996 effort, fish densities of all sized fish were even
lower, ranging from 21 to 79 fish/ha. We did not observe any
"stacking" that might be attributed to intake velocities. However, we
did observe that fish densities did sharply increase near the intake
tower at night. Higher fish densities were found near the surface.
Discussions with local anglers confirmed our belief that fish were
being attracted by the facility lights and this area is a popular
night fishing spot (Appendix D, Part 2).

Fish Densities and PODulation Estimates Hydroacoustic surveys
revealed that average pelagic fish densities for the entire reservoir
averaged 485 fish/hectare in June 1994, and decreased on subsequent
surveys (Table 4). August 1995 levels were measured at 201.1 fish/ha
which was between averages measured in August and October 1994.
Specific data is provided in Appendix C.

Table 4. Average densities of pelagic fish (fish/surface hectare)
detected using hydroacoustic equipment in the major arms (Lake Fork,
Soap, West Elk, and Cebolla ereeks), lola, Cebolla, and Sapinero
Basins of Blue Mesa Reservoir, Colorado, during June, August, and
October 1994.

Month
1994
June

Iola

eebolla SaDinero Rp:s Avo. (Ranoe)
855.3 575.2 484.6 (76-1528)
249.9
393.8 235.8 344.3 (28-686 )
215.9 255.3 329.8 (74-775)
130.7 84.8 149.4 (0-1220)
90.6' 96.3 110.1 (35-219)
196.8 239.1 201.1 (69-393)

Arms

113.0

172.3

August 282.5 475.2
303.4 498.8
October 355.1 109.0
109.9 166.7*
1995
August 172.5 196.0
. incomplete transect set

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