WSP09970

• File Number: 8200.766
• Description: Gunnison River General Publications-Correspondence-Reports
• State: CO
• Basin: Gunnison
• Water Division: 4
• Date: 7/1/1988
• Author: Colorado DOW
• Title: Historic Flow Data - Stream Fisheries Investigations - Federal Aid Project F-51-R - July 1988
• Water Supply Pro - Doc Type: Report/Study

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are reduced to 30-60 cfs during the incubation and hatching period. That
was the modus operandi in 1981, 1982, and again in 1988. The trout fishery
that exists in the South Platte below Cheesman Dam is as good as it is
because of restrictive angling regulations. These regulations effectively
reduce the harvest by about 95% or more, thus preserving older, larger fish
for several years that are then available for spawning and successful
reproduction when conditions are optimum, usually by accidental coincidence.

However, with meaningful minimum flow levels that are maintained during
the spawning, incubation, hatching, and emergence periods fishing in the
South Platte River would be even more consistent and better than it is now.
At present, successful reproduction takes place largely by accident by the
incidental convergence of natural hydrologic patterns and the DWD's
operational pattern of CheesDlan Reservoir. Typically, we have observed one
strong rainbow year-class about once every 5 years, i.e.,l976,' 1977;l982,
and a moderately good one in 1986. Clearly, it could be much better with
some attention to detail during the critical April-June period.

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Taylor River

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Brown trout are the'only viable wild trout population in the Taylor
River. The minimum flow for all life stages of brown trout is 50 cfs, while
optimum flows range from 50-250 cfs depending upon time and critical life
stage(s). The recommendations by life stage are contained in Table 3.

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Since 1977, the USBR.andUVWUAhave done an excellent job of flow"'
management out of Taylor River Reservoir that has dramatically ~mproved the
brown trout density and biomass in the Taylor River (Nehring, Anderson, and
Winters 1983). The agreements to ,stabilize releases out of Taylor Reservoir
prior to the onset of brown spawning in late October each year since 1976
has resulted in statistically significant increases in brown trout density.
Brown trout density increased by 90% during the flow-stabilization period of
evaluation (l979-82) over the pre-stabilization period of 1974-75 (Nehring
1988). '

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