7740

• UCREFRP Catalog Number: 7740
• Author: McAda, C. W. and L. R. Kaeding.
• Title: Physical Changes in the Gunnison and Colorado Rivers Resulting from Construction of the Aspinall Unit and Related Projects, with Hypotheses to Assess the Effects on the Endangered Fishes
• USFW Year: 1991.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

~i.
Table 1. Mean maximum-annual discharge (average of the highest mean-daily
flow for the year) for the Gunnison (Whitewater gage) and Colorado (Cisco
gage) rivers for three time periods: early development, middle development,
and post Aspinall development.
Percent Change
-------------------
Time Standard Period to Early to
River Period Mean Error Minimum Maximum Period Post
Colorado Early 45,870 3,158 16,800 73,200
Middle 35,425 2,827 12,100 63,400 -23
Post 28,873 3,089 4,970 69,500 -18 -37
Gunnison Early 17,116 1,529 3,735 35,175
Middle 13,673 1,301 3,170 27,340 -20
Post 9,003 1,090 1,020 23,140 -34 -47
Table 2. Comparison of streamflow changes in the Gunnison River (Whitewater
gage) estimated using two techniques. 1. Comparison of actual streamflows
with estimated flows that would have occurred without any water development
(1952-1965 and 1966-1983). 2. Comparison of actual streamflows during three
water development phases in the Gunnison River: early development (1917-1938),
middle development (1939-1965), and post Aspinall development (1966-1988).
Percent change in mean-monthly streamflow
----------------
Actual flow/ ------------------ -----------------
Actual flow/ --------------
estimated flow Middle period/ estimated flow Post Aspinall/
Month (1952-1965) early period (1965-1983) early period
APR - 16.1 - 6.6 - 21.8 - 8.0
MAY - 23.6 - 23.2 - 45.1 - 42.5
JUN - 25.4 - 21.8 - 52.9 - 46.9
JUL - 33.6 - 12.1 - 47.6 - 14.4
AUG - 40.1 - 7.3 - 27.7 + 14.0
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