WSPP283

• File Number: 8240.200.39.C
• Description: Colorado River Threatened-Endangered - RIPRAP - CFOPS - Water Availability
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 9/1/2003
• Author: Brown and Caldwell
• Title: Phase 2 Coordinated Facilities Water Availability Study for the Endangered Fishes of the Upper Colorado River - Final Report - 09-01-03
• Water Supply Pro - Doc Type: Report/Study

u00.788

As the Phase 2 investigation progressed it was necessary to make further modifications to the Cl Data
Set. The modifications are summarized in Table 2 and are further described in Appendix N. These
modifications primarily involve:

. Including the reduced demands for diversion resulting from the Grand Valley Project.

.

Including the maintenance periods for the Shoshone Hydropower Plant.

Turning on the correct operating rules in StateMod to model the reduced U.S.A.
Grand Valley Power Plant summer priority call.

Turning on the correct operating rules in StateMod to model the HUP operation in
accordance with the Orchard Mesa Check Setdement. .

Implementing the correct operations of fish pools in Ruedi, Williams Fork and
Wolford Mountain Reservoirs.

Turning on correct operating rules to meet USFWS and CWCB 15-Mile Reach
instream flow demands.

.

.

.

.

As a result of these modifications, there are five successive C1 Data Sets:

.

C1 Data Set: Data Set originally received from CWCB.

C1 Data Set (First Revision): Used in Technical Memoranda 1 through 4.

C1 Data Set (Second Revision): Used in Technical Memoranda 5 through 11 and for
.'sensitivity analysis in October 2001 Draft Phase 2 Report.

C1 Data Set (Third Revision): Used in February 2002 Draft Phase 2 Report analysis
and sensitivity analysis.

C1 Data Set (Fourth Revision): Used in March 2002 Draft Phase 2 Report analysis
and sensitivity analysis.

.

.

.

.

For each data set revision after the first, StateMod runs were made to compare results obtained with
the revised data set with results from the previous data set in order to determine if results had changed
sufficiendy to affect conclusions which were based on StateMod runs made with previous data sets.
As a result of these comparisons of StateMod results, the consultant team concluded that: (1) the
effects of the revised data sets were not sufficiendy significant to warrant re-running all of the previous
work with the revised data set and (2) conclusions based on StateMod runs using previous C1 Data
Sets were valid.

I)

Data Set revisions are further discussed in Table 2 and Appendix N.

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 P ACSIM model. In order to address this issue, the
Colorado Water Conservation Board (CWCB) modified StateMod and a fifth revision was made to the
Cl Data Set. A comparison of the base runs with the Cl Data Set (fourth revision) and the modified
StateMod and Cl 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

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P: \Data \ GEN\ CWCB\ 19665\Repon Phase 2\FinaIRepon9.03\Final_ CFOPS_Repon(9-03).doc