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

' It would be feasible to supply the 20,000 acre-feet to the 15-Mile Reach at a rate of approximately
1,000 cfs over a 10-day period during the eight years of the study period when it could be required.
This release/bypass could be made through existing Green Mountain Reservoir release facilities. It
would be feasible to supply the 20,000 acre-feet per year to the 15-Mile Reach without violating
downstream channel flow constraints on the Blue and/or Colorado Rivers.
Hydropower production at Green Mountain Reservoir was increased by an average of $10,085 Per
I
year while hydropower production at Ruedi Reservoir, Shoshone Power Plant and the Orchard Mesa
Power Plant were unaffected.
3.2.4 Alternative 1b: Modify Ruedi Reservoir Operations
This alternative attempted to make the 20,000 acre-feet release to the 15-Mile Reach from Ruedi
Reservoir and replace this release by diverting to storage under the Ruedi Reservoir refill right (See
Technical Memorandum No. 5, Appendix F).
The 1,100 cfs channel constraint on the Frying Pan River near Basalt precludes releasing the full
20,000 acre-feet over a 10-day period at an average release rate of 1,000 cfs. Making the full 20,000
acre-feet release is further complicated by the inadequate physical availability of inflow to Ruedi
' Reservoir that can be diverted to storage under the 1981 Ruedi Reservoir refill right to replace the
20,000 acre-feet release.
Calculations and sensitivity analysis were performed which indicated that Ruedi Reservoir could supply
approximately 7,000 acre-feet out of the total 20,000 acre-feet to the 15-Mile Reach without.
(1) violating downstream channel constraints and (2) reducing storage in Ruedi Reservoir. Supplying
' 7,000 acre-feet from Ruedi Reservoir is not expected to reduce storage in other west slope reservoirs
or to reduce deliveries through the Adams, Roberts, Boustead or Busk-Ivanhoe Tunnels. Average
annual hydropower revenues from Ruedi would be reduced approximately $4,000 to $18,000 per year
by this alternative. No reduction of hydropower revenues at Green Mountain Reservoir, Shoshone
Power Plant or Orchard Mesa Power Plant is anticipated from this alternative.
These results indicate that this alternative is not feasible for supplying the full 20,000 acre-feet but
should be further considered for supplying approximately 7,000 acre-feet toward the 20,000 acre-feet
target.
3.2.5 Alternative 1e: Denver Water System Operations
Analysis of this alternative is presented in Technical Memorandum No. 11 (see Appendix L) and
focuses on the feasibility of making the 20,000 acre-feet release from Williams Fork Reservoir. The
t consultant team, with approval from Denver Water, chose to model this alternative using Williams
Fork Reservoir because: (1) its purpose is to act as a supply of augmentation water for Dillon, and (2)
its location is further downstream than Dillon. The analysis was completed using StateMod with the
C1 Data Set. Because the Cl Data Set only includes the Colorado River basin, major components of
the Denver Water system located on the east slope are not included. Because of this, the initial results
from StateMod were provided to Denver Water for further analysis using Denver Water's own
models, data sets and computation procedures.
' PAData\GEN\CWCB\19665\Report Phase 2\FinalReport9.03\Final_CFOPS_Report(9-03).doc 34