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<br />Beneficial Consumptive Uses
<br />
<br />An extensive discussion of consumptive uses is treated in
<br />detail in Reclamation's draft "Colorado River System
<br />Consumptive Uses and Losses Report, 1981-1985," That
<br />report was prepared jointly by the Upper and Lower
<br />Colorado Regional Offices and was scheduled for release in
<br />1988, but has not yet been published due to technical review
<br />questions, The report presents estimates ofthe consumptive
<br />uses and losses from the Colorado River System for each year
<br />from 1981 through 1985. The table on the following page was
<br />created by the provisional data from that report, which
<br />summarizes annual water use from the system by States,
<br />including water use supplied by ground-water overdraft, The
<br />next report, 1986-1990, is expected to be available in 1992,
<br />
<br />Upper Basin Uses and Losses
<br />
<br />The three largest categories of consumptive use and losses in
<br />the Upper Colorado River Basin are agricultural uses within
<br />the basin, transbasin diversions to adjacent drainages, and
<br />evaporation losses from the major reservoirs of the Colorado
<br />River System, During water year 1989, the estimated use for
<br />municipal, industrial and agriculture supplies in the Upper
<br />Basin was about 3,0 maf, Estimated evaporation losscs were
<br />about 720,000 acre-feet from main stem reservoirs.
<br />Approximately 680,000 acre-feet was diverted for use in
<br />adjacent drainages, Total estimated consumptive use
<br />amounted to about 3,9 maL Storage in the Upper Basin
<br />mainstem reservoirs decreased by 2,6 maf during water year
<br />1989,
<br />
<br />Lower Basin Uses and Losses
<br />
<br />During water year 1989. an estimated 5,5 maf of water were
<br />re\eased from Lake Havasu to meet the requirements for
<br />water deliveries at Imperial Dam, as well as those of the
<br />Colorado River Indian Reservation near Parker, Arizona, the
<br />Palo Verde Irrigation District near Blythe. California, other
<br />miscellaneous users along the river, and transit losses between
<br />Parker Dam and Imperial Dam,
<br />
<br />The major water diversions above Parker Dam were by MWD
<br />and the CAP. MWD pumped approximately
<br />1,198.000 acre-feet from Lake Havasu during water year 1989
<br />
<br />and approximately 747,000 acre-feet were pumped for the
<br />CAP,
<br />
<br />Releases of approximately 7,7 maf were made from
<br />Lake Mohave during water year 1989, to provide for releases
<br />to meet minimum downstream needs in the United States at
<br />Parker Dam; to supply diversion requirements of MWD and
<br />CAP, miscellaneous contractors, and other users; to offset
<br />evaporation and other transit losses between Davis and
<br />Parker dams; and to maintain the scheduled levels of
<br />Lake Havasu,
<br />
<br />During water year 1989, releases of approximately 7.5 maf
<br />were made from Lake Mead at Hoover Dam to regulate the
<br />levels of Lake Mohave, to provide for the small users from
<br />Lake Mohave, and to provide for releases at Davis Dam to
<br />meet needs in the United States, In addition,
<br />243,000 acre-feet were diverted from Lake Mead for use by
<br />the Lake Mead National Recreation Area, Boulder City;
<br />Basic Management, Inc.; and contractors of the Colorado
<br />River Commission of Nevada, Total releases and diversions
<br />from Lake Mead during water year 1989 were an estimated
<br />9,270,000 acre-feet.
<br />
<br />For water year 1990, a total release of 6.5 maf from
<br />Lake Havasu is projected, including consumptive use
<br />requirements in the United States below Parker Dam, transit
<br />losses and regulation in the river between Parker Dam and the
<br />Mexican Border, and treaty deliveries to Mexico,
<br />
<br />During water year 1990, MWD is expected to divert
<br />1,312,000 acre-feet by pumping from Lake Havasu. The CAP
<br />is expected to pump approximately 848,000 acre-feet.
<br />Consumptive uses by small users, river losses or gains, and
<br />reservoir losses between Davis Dam and Parker Dam are
<br />projected to be a net loss of 46,000 acre-feet.
<br />
<br />There are no major users between Hoover Dam and
<br />Davis Dam, During water year 1990, diversions from
<br />Lake Mead are projected at 1%,000 acre-feet. Evaporation
<br />from Lake Mead is projected to be about 900,000 acre-feet
<br />and net gain between Glen Canyon Dam and Lake Mead is
<br />expected to be about 950,000 acre-feet.
<br />
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