WSP03158

• File Number: 8277.600.10
• Description: Big Sandy River Unit - Colorado River Salinity Control Program
• State: WY
• Basin: Colorado Mainstem
• Date: 11/1/1980
• Title: USDA Report - Big Sandy River Salinity Study
• Water Supply Pro - Doc Type: Report/Study

the underground aquifers. Of the total Big Sandy River system salt
output, it is estimated that through the base period of 1960-1977 return
flows from the irrigation delivery system seepage and deep percolation
from on-farm irrigation practices contribute about 124,900 tons annually.
Natural runoff , erosi on, and seeps contri buted an addi ti onal 24,300
tons annually.

A local Coordinating Committee, comprised of two board members of
the Eden Valley Irrigation and Drainage District, all of the board of
supervisors for the Big Sandy Conservation District, an appointed member
from the Wyoming Governor's Office, and a representative from the WPRS,
provided general guidance and a vehicle for local citizen input. The
Coordinating Committee reviewed the basic data and recommended several
on-farm irrigation management alternatives to increase irrigation
efficiencies and reduce deep percolation losses. In addition, the Coor-
dinating Committee requested that land retirement and irrigation retire-
ment alternatives also be analyzed. Eleven separate alternatives were
analyzed and presented to the Coordinating Committee and at a public
meeting. As a result of the public meeting, the Coordinating Committee
sent a questionnaire to all landowners to obtain their preferences.

As a result of the questionnaire and public meeting, a landowner
preferred alternative (Alternative 11) and landowner preferred-modified
alternative (Alternative 12) were forumulated. These alterantives were
analyzed and presented at a subsequent public meeting. General consensus
of the majority of landowners and the Coordinating Committee was to
select the "landowner preferred-modified alternative" (Alternative 12).
This modified alternative would retire from irrigation about 87 percent
(13,700 acres) of the irrigated area, with 13 percent (2,000 acres)
remaining under irrigation. Of the 2,000 remaining irrigated acres,
nearly all will need on-farm irrigation improvements to obtain better
irrigation efficiencies that will reduce losses to deep percolation.
This acreage would be supplied water by three pumps and distribution
pipelines direct from the Big Sandy River rather than through the
existing delivery system.

A large range of alterantives were evaluated during the course of
the salinity study. The alternatives range from no project action,
which did not reduce salinity from the project area, to various levels
of irrigation water management including irrigation retirement, which
provided greatest salinity reduction benefits. In addition to those
alternatives requested by the Coordinating Committee, two additional
alternatives were developed to meet two national objectives as specified
by "Principles and Standards for Water Related Land Resource Planning."
They were the National Economic Development (NED) (Alternative 8) and
Environmental Quality (EQ) (Alternative 13).

The alternatives evaluated and displayed in this report are listed
as follows:

Alternative 1 - Future Without a Project (No Action)

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