WSP09883

• File Number: 8273.100
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - BOR
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 9/1/1973
• Title: Colorado River International Salinity Control Project - Special Report - Executive Summary
• Water Supply Pro - Doc Type: Report/Study

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D. Gila River Control Measures below Painted Rock Dam

A further undertaking needed to control the salinity to carry
out the agreement with Mexico is the regulation, to the extent feasible,
of Gila River floodwaters that enter the Wellton-Mohawk District. This
is required to reduce inundation of District lands and attendant perco-
lation of waters into the ground, and thereby facilitate the District's
maintaining its underlying water table at safe levels, by pumping
of its wells at rates within the capacity of the District's drainage
conveyance channel. Pumping in excess of that capacity could result
in discharges of Wellton-Mohawk drainage waters to the Gila River which
would enter the Colorado River creating a serious problem in meeting
the 115 ppm !. 30 ppm TDS salinity differential commitment to Mexico.

To lessen this prospect, operating procedures would be developed
for the regulation of floodwaters in Painted Rock Reservoir, a Corps of
Engineers facility on the Gila River with a capacity of about 2.5 million
acre-feet. The new procedures would limit nood releases from the reservoir
to a rate that would not seriously affect the District. The implementation
of such operating procedures may require that the Corps of Engineers acquire
additional interests in reservoir lands at an estimated cost of $5 million.

Further investigations and studies may develop other control
measures, in lieu of, or, in addition to, the described reservoir
regulation, within the estimated cost. Such measures may include con-
struction of spreading grounds below Painted Rock Dam, possible diversion
facilities to utilize releases for agriculture, and development of a
greenbelt between Painted Rock Dam and the Wellton-Mohawk District, and
facilities to utilize releases in the Wellton-Mohawk irrigation distri-
bution system.

V. COACIIELLA CANAL

The Coachella Canal is a 123-mile long branch of the All-American
Canal, built in 1948 to serve about 67,000 acres of the Coachella
Valley in southeastern California. The first 86 miles of the canal
are unlined, while the last 37 miles are lined with concrete. For the
period 1955-1970, conveyance losses in the unlined portion averaged
about 160,000 acre-feet annually, or about one-third of all water
diverted into the canal. Studies indicate about 141,000 acre-feet
of the losses occur in the first 49-mile reach. The remaining
37 miles of unlined canal contribute about 19,000 acre-feet in water
losses.

Constructing a concrete-lined canal generally parallel to the first
49-mUe reach of the existing unlined canal would save an estimated
132,000 acre-feet of water annually.

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