WSP05094

• File Number: 8277.600.10
• Description: Big Sandy River Unit - Colorado River Salinity Control Program
• State: WY
• Basin: Colorado Mainstem
• Date: 2/1/1988
• Title: U.S.D.A. Selected Plan - Big Sandy River Unit
• Water Supply Pro - Doc Type: Definite Plan Report

The alternative that placed the entire canal system in pipeline for
low-pressure sprinkler irrigation proved to be very costly with a total
installation cost of near $70 million. Although this alternative showed
benefits exceeding costs, the project would have been marginal and the
operations, maintenance, and replacement costs could not have been paid
for from landowners' increased agricultural production. Therefore, this
alternative was not considered viable.

In 19R4, the SCS evaluated the low-pressure sprinkler irrigation project
(individual onfarm pumping stations). In addition, an economic
evaluation was made to update landowner benefits that will result fro~ a
sprinkler irrigation system. This evaluation was presented to the State
of Wvoming in November 1984. The Eden Valley Irrigation and Drainage
District held a public meeting December 17, 1984, at which time the
low-pressure sprinkler alternative was presented. Consensus from both
meetings was that both the State of Wyoming and local landowners will
support the low-pressure sprinkler alternative. The SCS was asked to
prepare a USDA Selected Plan for onfarm low-pressure sprinklers.
Letters from the State of Wyoming and Big Sandy Conservation District
are shown in the Appendix. As a result of these requests, the USDA
Selected Salinity Control Plan is a low-pressure onfarm sprinkler
irrigation plan with a total project cost of approximately $18 million.
About 72 percent of the benefits of the Selected Plan are attributable
to salinity reduction.

A large range of alternatives was evaluated during the course of the
salinity control study. The alternatives range from no project action
to various levels of irrigation water management including irrigation
retirement, which provided greatest salinity reduction benefits. In
addition to those alternatives requested by the Local Coordinating
Committee, an environmentally preferable alternative was developed.

The following are alternatives that are evaluated and displayed in the
Bi g Sandy EIS:

Alternative 1 - Future Without a Project (No Action)

Alternative 2 Improved Water Management and Minimum Structural
Improvements

Alternative 3 - 15,700 Acres Irrigated with Sprinklers (High
Pressure. Individual Pumping)

Alternative 4 - 14.200 Acres Irrigated with Automated Border
Systems and 1.500 Acres Sprinkler Irrigated

Alternative 5

Irrigation Retirement (Livestock Operation)

Alternative 6 - Sublettes Flat Reservoir and Wildlife Refuge
(Environmentally Preferred Alternative)

Alternative 7

Selected Plan - 15,700 Acres Irrigated With
Sprinklers (Low-Pressure. Individual Onfarm
Pumping) ()J 1 i 13

1-2

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