WSP09218

• File Number: 8200.765
• Description: Little Snake River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 7/31/1990
• Author: Western Water Consul
• Title: Final Report on Little Snake River Depletions by Pot Hook - Three Forks - and Powder Wash Rights
• Water Supply Pro - Doc Type: Report/Study

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OQG~-74'

For evaluation purposes, hydrographs of the average monthly flows for three "dry" years,

three "average" years and three "wet" years and for the minimum year and maximum year

are also shown in Appendix O. Comparisons for Scenario 1, lA and 18 are shown on

Figures 0-1 through 0-15.

4.2 SCENARIO NO.2 IMPACfS

Scenario No. 2 was the same as Scenario No. 1 with the addition of the

consolidated Three Forks Reservoir Project to the system. AIl reservoirs were modeled

assuming one-fill operations. The main modeling assumptions used for the Three Forks

Project are discussed in Section 3.2.3 of this report.

Anticipated industrial demands on Three Forks Reservoir storage water is unknown

at this time. To quantify realistic demands the reservoir could meet every month of the

study period, WWC performed a firm yield study with WIRSOS. A previous study by

WWC (SWEC, November 1984) indicated a firm yield of about 90,000 acre-feet per year

or a constant demand of 123 c.f.s. Therefore, the initial run of Scenario No.2 used the

constant industrial demand of l23 c.f.s. upon the reservoir. Modeling results showed that

this industrial demand was not met approximately 13 percent of the time. The reservoir

was in dead storage during these times and storage water was not available for industrial

diversion. Therefore, additional runs were performed with lower demands until the

reservoir could satisfy these demands about every month. The last WIRSOS run made

utilized an industrial storage demand of 80 c.f.s. This demand was met more than 99

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