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<br />l4SC,
<br /> Table 2
<br />CAPACITY, ACTIVE STORAGE. AND STORAGE CHANGE
<br />OF MAJOR COLORADO RIVER BASIN RESERVOIRS
<br />DURING WATER YEAR 1969-70
<br /> (Thousands of Acre.Feet)
<br /> Acti~'f'
<br /> Storage Change
<br /> Gro.'iS U S2ble Sept. 3D. During
<br />Uppcr B8~in Capacil.F O1p3ciry /9;0 }-'e,;lT
<br />Lake Powell 27.000 25.002 12,039 +2,JJI
<br />Flaming: Gorge .. 3,789 3.749 1,791 -35
<br />Navajo 1.709 1,696 1,261 + 117
<br />Blue Mesa 941 830 810 + 90
<br />fontenelle 345 345 2~6 -41
<br />Morrow Poi nr . 117 117 117 + 76
<br />Subtotal 33,901 31,739 16.264 +2,538
<br />LOl+"u Basin
<br />Lake Mead . 28,537 26.159 16,769 + 638
<br />Lake Mohave .... 1.818 1,810 1,376 -65
<br />Lake Havasu 648 619 SS7 -8
<br />Subtotal )1,003 28,588 18.702 + 565
<br />Total Both Basins .... 64.904 60.327 34.966 +3.104
<br />
<br />Plate 4 shows the combined active surface
<br />storage and capacity of Lake Mead and the
<br />Colorado River Storage Project reservoirs for
<br />the period 1935-70. Lake Mohave and Lake
<br />Havasu are not included in Plate 4 because
<br />they are operated at relatively constant lev-
<br />els, In addition to surface storage, water is
<br />
<br />PLATE 4
<br />
<br />COLORADO RIVER BASIN RESERVOIRS
<br />~TORAGE AND CAPACITY
<br />
<br />
<br />12
<br />
<br />absorbed in the areas adjacent to the reser-
<br />voirs as bank storage, As of the end of 1970,
<br />bank storage at Lake Powell was estimated to
<br />be about 5,800,000 acre-feet, or 41 percent of
<br />the gross surface storage of 14,037,000 acre-
<br />feet (12,039,000 active storage + 1,998,000
<br />dead storage).
<br />Plate 5 shows the changes in contents of
<br />the major main stream reservoirs during
<br />1969-70,
<br />
<br />1
<br />
<br />I
<br />
<br />Water Uses in the United States
<br />
<br />Upper Basin. The depletion of the river
<br />at Lee Ferry is a result of inbasin consump-
<br />tive use, transbasin diversions and reservoir
<br />evaporation, The major depletions are due to
<br />inbasin use which is not measured. The pre-
<br />liminary total depletions in 1969-70 at Lee
<br />Ferry were estimated by the U.S, Bureau of
<br />Reclamation to be 3,018,000 acre-feet, an in-
<br />crease of 58,000 acre-feet from the estimated
<br />1968-69 depletion. A breakdown of this fig-
<br />ure is as follows:
<br />
<br />Acre-Feer
<br />Within Basin Depletions ................................2, I 39,000
<br />Transbasin Diversions .................................... 469,000
<br />Reservoir Evaporation .................................... 410,000
<br />
<br />TOlal ................................................................ 3,0 18,000
<br />
<br />Lower Basin. Diversions minus meas-
<br />ured returns to the river by the major Lower
<br />Basin mainstream users in 1969-70 were 5,-
<br />870,000 acre-feet, a decrease of 7,000 acre-feet
<br />from 1968-69. California diversions less
<br />measured returns to the river were 4,836,000
<br />acre-feet, a decrease of 10,000 acre-feet from
<br />the previous year.
<br />O!Jantities for the past five years are
<br />shown in Table 3.
<br />In addition to the major Colorado River
<br />water users listed in Table 3, miscellaneous
<br />users divert from the Colorado River or
<br />pump from wells adjacent to the main
<br />stream. For the past several years, gross di-
<br />versions by these miscellaneous users in Cali-
<br />fornia, Arizona, and Nevada are estimated to
<br />have amounted to more than 150,000 acre-
<br />feet a year.
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