WSP04272

• File Number: 8277.600.10
• Description: Big Sandy River Unit - Colorado River Salinity Control Program
• State: WY
• Basin: Colorado Mainstem
• Date: 3/1/1989
• Title: Planning Report Concluding the Study on Big Sandy River Unit - Wyoming
• Water Supply Pro - Doc Type: Report/Study

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SUMMARY

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This report concludes the Bureau of Reclamation (Reclamation)
planning study of the Big Sandy River Unit, Wyoming, Colorado
River Water Quality Improvement Program. The study was concluded
because a cost effective alternative could not be identified
based on current cost effectiveness procedures. In addition,
Reclamation could not obtain an appropriative right to water from
the unit because a beneficial user of the saline water was not
identified. A significant amount of information about the unit
area was gathered during the course of the study, and this report
was prepared to document that information.

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The Big Sandy River Unit is in southwest Wyoming in the Upper
Colorado River Basin. The unit area includes portions of
Sweetwater and Lincoln Counties. Rock Springs and Green River
are principal cities in the unit area. The unincorporated
communities of Farson and Eden along the Big Sandy River are
central to this investigation.

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Purpose and Scope

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The purpose of the Big Sandy River Unit investigations was to
identify and delineate the saline ground-water source which is
contributing salt to the Colorado River and to evaluate plans to
reduce or eliminate that contribution. The Big Sandy River Unit
contributes an estimated 164,000 tons of salt annually to the
Colorado River, which represents about 2 percent of the average
salt loading at Imperial Dam. The primary sources of salt
loading are springs and seeps along a 26-mile reach of the river
below Farson, Wyoming. The average annual flow of springs and
seeps is about 27 cubic feet per second (cfs) and the concen-
tration varies from 1,000 to 6,000 milligrams per liter (mg/L).

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At its headwaters in the mountains of north-central Colorado, the
Colorado River has a salinity concentration of 50 mg/L.
Downstream, the concentration progressively increases because of
irrigation diversion and salt contributions from a variety of
sources. In 1987, salinity averaged 621 mg/L at Imperial Dam,
the last major diversion point in the United States. Future
development in the Colorado River Basin is projected to increase
salinity to an average of 966 mg/L at Imperial Dam by the
year 2010.

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In the Lower Colorado River Basin, high salinity levels adversely
affect more than 18 million people and about 1.7 million acres of
irrigated farm land. Those affected most are the municipal and
industrial water users in the Los Angeles-San Diego area and

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