WSP12299 - Laserfiche WebLink

Home Browse Search

Water Quality 26 Control ":ater QuatH" OperatioDS Uuring Water Year 1975 Since water quality aspects of Colorado River operations are extensively described in the bi- ennial 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.7 of the biennial series was issued in January)975. During water year 1975, the Unit- ed Stale, bypa,sed 213,468 acre. feet of drainage water to the Cola- cado River below Morelos Dam and replaced it with a like amount of other water, pursuant to minute No. 242 with Mexico. Even though this was the only specific opera- tion carried out for quality pur- poses, other incidental benefits accrue to water quality from nor~ mal procedures. Water is stored in reservoirs during the non irrigation season and during the snowmelt runoff period when it is surplus to immediate requirements. As the strearuflows diminish in late summer, storage water is released to supplement the natural streamflows, thu9 diluting the more saline flows that would otherwise occur during late sum. mer and fall. Although water quality control is not generally recognized as a beneficial use of surface water, water released for other purposes during normally low flow periods greatly enhances the quality of water in the Basin. ]n recognizing the need to manage waler quality of the Colorado River, it has been recommended that salinity increases in the river will be minimized through a water quality improvement program gen- erally descrihed in the Department of the Interior's report, "Colorado River Quality Improvement Pro- gram," dated February 1972. The program calls for a basin-wide approach to salinity control while the Upper Basin continues to develop its Compact-apportioned waters. To enhance and improve the quality of the river's water, Congress authorized the Colorado River Basin Salinity Gontrol Act (P.L. 93-320), June 24,1974.