WSP04117

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1976
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1976 Projected Operations 1977
• Water Supply Pro - Doc Type: Publication

Water Quality Control

Water Quality Operations
During Water Year 1976

Since water quality aspects of Colorado River
operations are extensively described in the bien-
nial series of reports entitled "Quality of Water,
Colorado River Basin," only minimal discussion
of this aspect of operation is presented in this
report. Report No, 8 of the biennial series will be
issued in January 1977,

During water year 1976, the United States by-
passed 205,586 acre-feet of drainage water to the
Colorado River below Morelos Dam and replaced
it with a like amount of other water, pursuant to
Minute No. 242 of the Treaty with Mexico. Even
though this was the only specific operation carried
out for quality purposes, other incidental benefits
accrue to water quality from normal procedures.
Water is stored in reservoirs during the nonirriga-
tion season and during the snowmelt runoff period
when it is surplus to immediate requirements. As
the streamflows diminish in late summer, storage
water is released to supplement the natural
stream flows, thus diluting the more saline flows

that would otherwise occur during late summer
and fall. Although water quality control is not gen-
erally recognized as a beneficial use of surface
water, water released for other purposes during
normally low flow periods enhances the quality
of water during those periods.

In recognizing the need to manage water quality
of the Colorado River, it has been recommended
that salinity increases in the river be controlled
through a water quality improvement program gen-
erally described in the Bureau of Reclamation's
reporl, "Colorado River Quality Improvement Pro-
gram," dated February 1972 and a status report
of the same title dated January 1974, The program
calls for a basinwide approach to salinity control
while the Upper Basin continues to develop its
compact-apportioned waters, The initial step to-
wards improvement of the quality of the river's
water was authorizalion by the Congress of the
Colorado River Basin Salinity Control Act (P.L.
93-320), June 24,1974.

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