10825 Water Supply Alternative Summary Phase 2 Assessment January 2008 Draft

• Description: A report from the Grand River Consulting Corporation on alternatives for delivering 10,825 AF of water to the 15-mile reach of the Colorado River.
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/2008
• Author: Grand River Consulting Corporation
• Title: 10825 Water Supply Alternative Summary Phase 2 Assessment January 2008 Draft
• Water Supply Pro - Doc Type: Report/Study

4.0 RECOVERY PROGRAM WATER RELEASE PRINCIPLES
In order to assess the impacts associated with potential 10825 Water supply alternatives, it is
necessary to first estimate the timing and magnitude of 10825 Water releases. The following
information was considered to identify specific study years and specific water release schedules.
4.1 STUDY YEARS
In their 1995 report entitled "Relationships between Flow and Rare Fish Habitat in the 15 Mile
Reach of the Upper Colorado River ", the U.S. Fish and Wildlife Service ( USFWS) recommended
15 Mile Reach stream flow targets for four categories of years (Table 1). Dry years were defined
as the driest 20 % of years, and wet years were defined as the wettest 25 % of years. Flow
recommendations were also provided for above average years, and for below average years. In
coordination with these recommendations, the four individual study years noted on Table 1
were selected for this evaluation.
4.2 RELEASE SCHEDULES
Recovery Program water is available from the four sources listed in Table 2. The total amount of
water available to the Recovery Program varies by type of year, and is estimated to range from a
low of 21,825 acre feet to a high of about 65,825 acre feet. These estimates in Table 2 do not
reflect the existing contract for 10,825 acre feet of water from Ruedi Reservoir, as this contract
expires in the year 2012.
10825 fatc Supply Study Phase 2 Alternatives ssessment Jane -ary 2008 Draft
Table 1
USFWS Summer and Fall
Stream Flow Recommendations
15
Mile Reach
Flow
Proposed 10825 Study
Year
% Exceedance
Recommendation
Year
Dry
80 % to 100 %
810 cfs
1977
Below Average
50 % to 80 %
1,240 cfs
1988
Above Average
25 % to 50 %
1,630 cfs
1982
Wet
0 % to 25 %
1,630 cfs
1983
4.2 RELEASE SCHEDULES
Recovery Program water is available from the four sources listed in Table 2. The total amount of
water available to the Recovery Program varies by type of year, and is estimated to range from a
low of 21,825 acre feet to a high of about 65,825 acre feet. These estimates in Table 2 do not
reflect the existing contract for 10,825 acre feet of water from Ruedi Reservoir, as this contract
expires in the year 2012.
10825 fatc Supply Study Phase 2 Alternatives ssessment Jane -ary 2008 Draft