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<br />Beneficial Consumptive Uses
<br />
<br />An extensive discussion of consumptive uses is treated in
<br />detail in Reclamation's "Colorado River System
<br />Consumptive Uses and Losses Report, 1981-1985." This
<br />reporl is prepared jointly by the Upper and Lower Colorado
<br />Regional Offices. The report presents estimates of the
<br />consumptive uses and losses from the Colorado River System
<br />for each ycar from 1981 Ihrough 1985. The table on Ihe
<br />following page was created using lhe data from Ihc
<br />Consumpti", Uses and Losses Report (June 1991). The lab Ie
<br />sununarizes annual water use from the system by Stales,
<br />including waler use supplied by ground,water o",rdraft. The
<br />1986-1990 report, is expecled lo be available in 1992.
<br />
<br />Upper Basin Uses and Losses
<br />
<br />The three: largest categories of consumptive use and tosses 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. Estimated
<br />evaporation losses were aboul59l,OOOacre-feet from Upper
<br />Basin reservoirs in waler year 1991. In wat~r year 1990,
<br />746,244 acre-feet were diverted for use in adjacent drainages.
<br />The total for transbasin diversions in water year 1991 has not
<br />yet been tabulated but the figure is expected to be similar to
<br />the 1990 lotal.
<br />
<br />l..o~r Basin Uses and Losses in the United States
<br />
<br />During wJ,ter year 1991, an estimated 5.5 million acre. feet of
<br />water 'Were released from Lake Havasu (Parker Darn) to meet
<br />the requirements for water deliveries at Imperial Dam, as well
<br />as those of the Colorado River Indian Reservation near
<br />Parker, Arizona, the Palo Verde Irrigation District near
<br />Blythe, California, other miscellaneous users along the river,
<br />and transit losses between Parker Dam and Imperial Dam.
<br />
<br />The major water diversions abo\-C Parker Dam were by The
<br />Mctropolilan Waler District (MWD) of Southern California
<br />and the Central Arizona Project (CAP). MWD pumped
<br />approximately 1,253,000 acre-feel from Lake Havasu during
<br />walcr ycar i991, and approximateiy 473,000 acre-feel were
<br />pumped for the CAP.
<br />
<br />Releases of approximately 8.4 mi1lion acre-feet were made
<br />from Lake Mohave during water year 1991, to provide for
<br />releases to meet minimum downstream needs in the U oired
<br />States at Parker Darn; to supply diversion requirements of
<br />MWD and CAP, miscellaneous contractors, and other users;
<br />to offset evaporation and other transit losses between Davis
<br />and Parker dams; and 10 mainlain the scheduicd Ic",lsofLake
<br />Havasu.
<br />
<br />During water ycar 1991, reicases of approximately 8.9 million
<br />acre-feet were made from Lake Mead at Hoover Dam. These
<br />releases regulate the levels of Lake Mohave, provide for the
<br />small users on that reservoir ,and provide for releases at Davis
<br />Dam to meet needs in the United States as well as deliveries
<br />to t\1exico. In addition, 270,000 acre-feet were diverted from
<br />Lake Mead for use by the Lake Mead National Recreation
<br />Area; Boulder City; Basic Management, Inc.; and contractors
<br />of the Colorado River Commission of Nevada. Of the
<br />di",rsions from Lake Mead, approximately 160,000 acre,feel
<br />were consumptively used and the remainder returned to Lake
<br />Mead. Total releases and diversions from Lake Mead during
<br />water year 1991 were an estimated 9,200,000 acre-feel.
<br />
<br />For water year 1992, a total release of 7.0 million acre-feet
<br />from Lake Havasu is projected, including consumptive use
<br />requirements in the U nitc-d States below Parker Dam, transit
<br />losses and regulation in rhe river between Parker Damand the
<br />Mexican Border, and treaty deliveries to Mexico.
<br />
<br />Based on studies made in October 1991, it is expected that
<br />MWD wiU di",rt 1,300,000 acre-feet by pumping from Lake
<br />Havasu during water ycar 1992. Similarly,lhc CAP isexpeclcd
<br />to pump approximately 645,000 acre-feel. These figures may
<br />change as the water year progresses. Consumptive uses by
<br />small users, river losses or gains, and reservoir losses between
<br />Davis Dam and Parker Dam are projected to be a net ~oss of
<br />66,000 acre-feel.
<br />
<br />There are no major users between Hoover Dam and Davis
<br />Dam. Duringwater ycar 1992, di",rsions from Lake Mead are
<br />projected at 308,000 acre-feel. Evaporation from Lake Mead
<br />is projccled to be about 820,000 acre,feel and net gain
<br />belween Glen Canyon Dam and Lake Mead is expected to be
<br />about 820,000 acre-feet.
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