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

6.0 GENERAL OBSERVATIONS: "A to Z"
Through the evaluation process, the study team has developed the following key observations.
These observations are important for the 10825 Steering Committee to consider as this group
evaluates specific alternatives to fulfill both the obligations of the Water Providers under the
Programmatic Biological Opinion AND to support the broader goals of actually recovering the
target fish species through the Upper Colorado River Endangered Fish Recovery Program. These
observations also strongly influenced the identification of the most promising alternatives,
which are presented later in this summary.
6.1 BENEFIT TO THE ENDANGERED FISH RECOVERY PROGRAM
a) Six alternatives are recommended as most promising in this report. Each of these
alternatives would benefit the 15 Mile Reach by providing 10,825 acre feet of water per
year.
b) The water sources available to the Recovery Program (Green Mtn. Reservoir surplus, Ruedi
Reservoir 5 & 5 water, Wolford Mtn fish pool, and 10825 Water) will not increase stream
flow in the 15 Mile Reach to the point that the USFWS target flow prescriptions are met in
dry years, or even in below average years. While minimum dry year targets call for 810 cfs
(1,240 cfs in below average years) in the 15 Mile Reach, the release of all the available
Recovery Program water will maintain a flow of less than half of the targets (about 400 to
500 cfs) in drier years.
c) It is important to efficiently manage and coordinate releases of the 10825 Water along with
all other Recovery Program sources of water, in order to maintain as consistent a flow as
possible in the 15 Mile Reach, especially in drier than average years when flow targets will
not be met.
d) The completion of fish passage improvements at the Price -Stubb dam will provide the
endangered fish with new access to lengthy segments of the Colorado River that have
relatively high stream flow throughout the year. When all of the related fish passage
elements that have been put in place on the Colorado River are operational, they will have a
positive impact on the potential recovery of the endangered fish. The provision of 10825
Water, while important, may have less impact on the recovery of the fish than other
Recovery Program elements such as the fish passage improvements.
e) Releases of 10825 Water from alternatives that utilize Sulphur Gulch Reservoir would
provide the most benefit to the 15 Mile Reach and to the Recovery Program, as long as
appropriate operational and design criteria are implemented. This facility is close to the 15
Mile Reach, and reservoir releases can be timed in response to fluctuating stream flow of
the Colorado River. The flexibility in release patterns associated with Sulphur Gulch
Reservoir would maximize the effectiveness of the limited water supplies available to the
W5 VA.'at3r Suppl y Study Phase 2 `Ater at vos tsse; sment January 2008 Drat 8