9570

• UCREFRP Catalog Number: 9570
• Author: U.S. Department of the Interior.
• Title: Preliminary Analysis
• USFW Year: 2000.
• USFW - Doc Type: Wayne N. Aspinall Unit Operations and the Federal Water Right Claim, Black Canyon of the Gunnison National Park.
• Copyright Material: NO

Flood Control
The Water Control Manual (Corps of Engineer publication signed by Reclamation and the Corps)
for Blue Mesa Reservoir requires Reclamation to operate Blue Mesa to prevent flows at Delta
from exceeding 15,000 cfs if possible. Reclamation recognizes that flooding becomes an issue in
the Delta area with flows less than 15,000 cfs and have historically coordinated operations to
keep these flows at Delta below 14,000 cfs when possible. This may still result in localized
flooding.
There does not appear to be a relationship between the individual NPS desired flow model runs
and the peak flows at Delta. It appears that the actual peak at Delta with any one model run is a
function of the runoff timing from other tributaries, rather than the date of the NPS desired flow
peak or limitations applied to the model runs. The following table compares peak flows at Delta
for years when operating for NPS desired flow peaks could have potential impacts.
Peak Flows at Delta, Colorado in Selected Years
Year Base Run NPS Desired Flow Runs
1979 10,000 12,800 - 14,900
1980 10,700 12,100 - 15,400
1983 12,400 13,300 - 14,900
1984 18,800 22,900 - 23,300
1985 16,700 14,100 - 17,500
1993 15,200 15,400 - 17,600
1995 13,900 15,500 - 17,000
1997 10,400 12,700 - 15,100
The specific impact on Delta flooding due to operating to provide NPS desired flows cannot be
evaluated from these runs, but the general impacts or potential for impacts can be summarized.
General observations from model runs indicate that flooding at Delta may be increased under the
conditions summarized in the following table:
r?
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