9600

• UCREFRP Catalog Number: 9600
• Author: Brown and Caldwell.
• Title: Phase 2 Coordinated Facilities Water Availability Study for the Endangered Fishes of the Upper Colorado River - Final Report.
• USFW Year: 2003.
• USFW - Doc Type: \
• Copyright Material: NO

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3. Based on the results of sensitivity analysis, it appears that it should be possible to
make the CROPS bypasses and the 20,000 acre-feet release and have only limited
effects on junior water rights.
4. Results of sensitivity analysis indicate that if an alternative s, feasible under the current
conditions of the C1 Data Set, it is likely to remain feasible under future flow
conditions in which there would be up to approximately 120,000 acre-feet of
additional depletions.
5. Sensitivity analysis on estimated CROPS bypasses, reduced Grand Valley Project
demands, Palisade Pipeline bypasses and the Shoshone Power Plant maintenance
schedule indicates continued feasibility of the alternatives investigated in the Technical
Memoranda. Sensitivity analyses involving these parameters indicate there would be
little effect on availability of Green Mountain Reservoir storage for making the 20,000
acre-feet release from CROPS bypasses, reduced Grand Valley Project demands,
Palisade Pipeline bypass flows and the Shoshone Power Plant maintenance schedule.
Including CROPS bypasses, however, would not always leave sufficient release
capacity through the Green Mountain Reservoir turbines to make the 1,000 cfs
Coordinated Facilities Operation Study (CFOPS) release during the 10-day peak flow.
This lack of sufficient release capacity at Green Mountain Reservoir would necessitate
allocating responsibility for making a portion of the 20,000 acre-feet CFOPS release to
other reservoirs. The opportunity for Green Mountain Reservoir to function as an
insurance pool in-these situations-and-payback the-other reservoirs could also be
considered.
6. An analysis was made of the effect on Colorado River flows at the head of the 15-Mile
Reach to determine if making the 20,000 acre-feet release generally during June would
reduce flows during other months. Results of this analysis indicate that the maximum
average monthly reduction occurred during July and reduced flows in that month by
1,048 acre-feet (295,601 acre-feet to 294,553 acre-feet).
Throughout the investigation, it was noticed that the exchanges and substitutions among Dillon,
Williams Fork, and Wolford Mountain Reservoirs using the C1 Data Set in StateMod differed from
the simulations by Denver Water using their daily PACSIM model. In order to address this issue, the
Colorado Water Conservation Board (CWCB) modified StateMod and a fifth revision was made to the
C1 Data Set. A comparison of the base runs with the C1 Data Set (fourth revision) and the modified
StateMod and C1 Data Set (fifth revision) was made to determine if these changes were sufficient to
necessitate redoing the previous work with the modified StateMod and C1 Data Set (fifth revision). A
comparison of these two base runs indicated that a difference remained, which was increased storage
in Dillon Reservoir and decreased storage in Williams Fork Reservoir. In order to further check the
need for rerunning previous simulation runs with the modified StateMod and C1 Data Set (fifth
revision), simulation runs for two alternatives were made: (1) Green Mountain Reservoir making the
20,000 acre-feet release and replacing this release using its refill priority and (2) the "Share the Pain"
with responsibility for making the 20,000 acre-feet release divided equally among Granby, Green
Mountain and Williams Fork Reservoirs. Results of these additional simulation runs did not differ
significantly enough to change original conclusions presented in the Technical Memoranda concerning
these alternatives. However, comparing simulations by Denver Water using its daily PACSIM model
with StateMod showed differences in accounting for exchanges and substitutions into and out of
PAData\GEN\CWCB\19665\Report Phase 2\FinalReport9.03\Final_CFOPS_Report(9-03).doc