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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OO~~oS

P&M holds two separate rights for the Three Forks Reservoir which is located on the

Wyoming-Colorado state line. The Colorado decrees for Three Forks and Sheep Mountain

Reservoirs, dated June 5, 1972, each call for 75,000 AF of storage. The Wyoming permit

for Three Forks Reservoir, dated June 20, 1972, is for a dam at the same location as the

Colorado Three Forks Reservoir decree except with a storage amount of 22,865 AF.

According to P&M, their future plans are to develop a single large dam on the

Little Snake River with a total capacity of 172,865 AF at the common site of its Wyoming

Three Forks Permit and Colorado Three Forks Decree to embody the full entitlement of

these rights as well as the Sheep Mountain Reservoir Decree water. Therefore, this study

evaluated the impacts of a consolidated Three Forks Reservoir with 172,865 AF of storage.

For this study, it was assumed that all components of the project are in place at

the beginning of the study period. The main project components modeled are shown on

a general schematic diagram (See Figure 5, page 23).

Table 5 summarizes the Three Forks Project input data used in the WIRSOS

modeling. Of the total storage capacity, 10 percent (17,300 AF) was assumed for study

purposes to be dead or inactive storage and the remaining 155,565 AF as active storage.

This assumption was made for study purposes and was not based on a biological or other

environmental constraint evaluation. An area-capacity curve for the consolidated Three

Forks Reservoir has been developed by P&M (see Appendix C) and was incorporated into

the WIRSOS input.

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