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<br />Beneficial Consumptive Uses
<br />
<br />An extensive discussion of consumptive uses is not attempted
<br />in this report as that subject has been treated in detail in
<br />Reclamalion's "Colorado River System C9nsumptive Uses
<br />and Losses Report, 1981-1985." This report has been
<br />prepared jointly by the Upper and Lower Colorado Regional
<br />Offices and is due to be released in 1988. II presents estimates
<br />of the consumptive uses and losses from the Colorado River
<br />System for each year from 1981 through 1985, The table on
<br />the following page summarizes annuai water use from the
<br />system by States, including water use supplied by
<br />ground-water overdraft.
<br />
<br />Upper Basin Uses and Losses
<br />
<br />The three largest categories of consumptive use in the Upper
<br />Colorado River Basjn afe agricultural uses within the basin,
<br />translJasin diversions to adjacent drainages. and evaporation
<br />losses 6:0111 the Illajor reservoirs of the Colorado River
<br />System. During water year 1987, the estimated use for
<br />municipal and industrial supply and for agriculture in the
<br />Upper Basin was 2,900,000 acre-feel. Estimated evaporation
<br />losses were 610,000 acre-feet from mainstem reservoirs,
<br />About 670,000 acre-feet was diverted for use in adjacent
<br />drainages. Total estimated consumptive use amounted to
<br />3,800,000 acre-feel. Stonlge in the Upper Basin mainstem
<br />reservoirs decreased by approximately 871,000 acre-feet
<br />during water year \987,
<br />
<br />Lower Basin Uses and Losses
<br />
<br />During water year 1987, an estimated 5,2 MAF of water were
<br />released 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, Ariz.ona, the
<br />Palo Verde Irrigation District near Blythe, California, other
<br />miscellaneous users along the river, and transit losses between
<br />Parker Dat11 and Imperial Dam.
<br />
<br />The major water diversions above Parker Dam were by MWD
<br />and the CAP. MWD pumped approximately 1.31 MAF from
<br />Lake Havasu during water year 1987 and approximately
<br />356,000 acre-feet were pumped for the CAP.
<br />
<br />Releases of approximately 6,9 MAF were made from Lake
<br />Mohave during water year 1987, to provide for releases to
<br />meet minimum downstream needs in the United States at
<br />Parker Dam; to supply diversion requirements of MWD and
<br />CAP. miscellaneous contractors, and oth~r users~ to offset
<br />evaporation and other transit losses between Da vis and
<br />Parker Dams; and to maintain the scheduled levels of Lake
<br />Havasu.
<br />
<br />During water year 1987, releases of approximately 6,8 MAF
<br />were made from Lake Mead at Hoover Dam to regulate the
<br />levels of Lake Mohave and to provide for the small users from
<br />that reservoir, and to provide for releases at Davis Dam to
<br />meet needs in the United States. In addition, 180,000 acre-feet
<br />were diverted from Lake Mead for use by the Lake Mead
<br />National Recreation Area, Boulder City, Basic Management,
<br />Inc, and contmctors of the Colorado River Commission of
<br />Nevada, Total releases and diversions from Lake Mead
<br />during water year 1987 were an estimated 13.32 MAF.
<br />
<br />For water year 1988, a total release of 8,7 MAF from Lake
<br />Havasu is projected, including consumptive use requirements
<br />in the United States below Parker Dam, transit losses and
<br />regulation in the river between Parker Dam and the Mexican
<br />Border, flood control requirements, and treaty deliveries to
<br />Mexico.
<br />
<br />During water year 1988, MWD is expected to divert 1.34 MAF
<br />by pumping from Lake Havasu, The CAP is expected to
<br />pump approximately 747,000 acre-feel. 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 loss of
<br />7,000 acre-feet,
<br />
<br />There are no major users between Hoover Dam and Davis
<br />Dam, During water year 1988 the net diversions from Lake
<br />Mead are projected at 140,000 acre-feet. Evaporation from
<br />Lake Mead is projected to be about 980,000 acre-feet and net
<br />gain between Glen Canyon Dam and Lake Mead is expected
<br />to be about 780,000 acre-feet.
<br />
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