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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2.0 STUDY APPROACH

An assessment of the impacts of the Pot Hook, Three Forks, Sheep Mountain, and

Powder Wash projects upon Little Snake River flows at Lily, Colorado was determined

using the WIRSOS digital simulation model of the Little Snake River Basin. The following

sections of this chapter discuss the WIRSOS model, justifications for its use for this study,

a description of previous applications of WIRSOS for the Little Snake River Basin, and

its application for this study.

2.l GENERAL DESCRIPTION OF WIRSOS MODEL

The Wyoming Integrated River System Operation Study (WIRSOS) Model was

originally developed by Leonard Rice Consulting Water Engineers, Inc., Denver, Colorado

for the State of Wyoming as a tool for assessing the impacts of various water rights claims

associated with the Big Horn River adjudication. Since its development, WIRSOS has

been used to evaluate other projects in Wyoming including Sandstone Reservoir in the

Little Snake River Basin.

WIRSOS is a river system model specifically coded to quantify streamflows and

simulated reservoir operations and direct flow diversions under priority administration. It

may be used to model reservoirs within a basin and assess the ability of reservoirs to

supply water, as a total supply or supplemental supply, to associated lands. WIRSOS

operates on a strict prior appropriation basis. The most senior priority water right

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