1006

• UCREFRP Catalog Number: 1006
• Author: Resource Consultants, I.
• Title: Biological Assessment Green Mountain Reservoir Water Marketing Program.
• USFW Year: 1985.
• USFW - Doc Type: Denver.
• Copyright Material: NO

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IMPACT ASSESSMENT

Alternative 4 - Maximum Water Sales (28,800 ac. ft.)

FISH

Colorado Squawfish
Flow depl etion in the Colorado River has been a major factor in the
past decline of Colorado squawfish (Holden 1983, Holden and Wick 1982).
The Green Mountain Water Sales project would alter the flow of the
Colorado River by augmenting the flow at times, and depl eting it at
other times. Tables 3 shows the monthly flow depletions with sales for
Cameo and Statel ine for wet, dry and average years. During the average
year, flow reductions during late fall and winter are generally 20-35
cfs, or about a 1-2 percent change at Cameo. Flow augmentation of 5-10
cfs would occur in May, June, August and September. July shows a 53 cfs
reduction in flow, which would only be a 1.5 percent change. During the
dry year (1978), flows would be altered by 2-4 percent, with the largest
depletion (132 cfs) occurring in July. These small depletions by them-
selves would not affect Colorado squawfish, even though they would
sl ight1y decrease flows all the way downstream to Lake Powell. The
exception to this would be the July 132 cfs withdrawal during the dry
year. This withdrawal would affect the 15-mi1e reach of the river just
above the Gunnison River which is presently nearly dry during low flow
periods. The Green Mountain depletions would increase the intensity and
duration of dryness in this 15-mile reach. Since that would only occur
every 20-30 years, the squawfish population would probably not be
significantly affected.

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