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<br />2157
<br />
<br />,..!Il,-l;nf7 tranSffiQUntam c1iver'\ions \vhich :lTe
<br />_.~~'uo
<br />measured, and evaporation from reservoirs, total
<br />depletion in 1965-66 is calculated by the Bureau
<br />to be 2,029,000 acre-feet, a decrease of 661,-
<br />000 acre-feet from the estimated 1964-65 de-
<br />plerion. This large apparent decrease raises ques-
<br />rions as to rhe Hureau of Reclamarion's merhod
<br />of computing deplerions.
<br />Diversions minus measured rerurns to the
<br />river b\' Lower Basin mainstream users in water
<br />year 1965-66 were 5,746,000 acre-feet, a reduc-
<br />tion of 134,000 acre-feet from 1964-65.
<br />Quantiries for the past five years arc shown
<br />in Table 4.
<br />
<br />Table 4
<br />
<br />DIVERSIONS MINUS MEASURED RETURNS
<br />lOWER COlORADO RIVER
<br />(Thousands of Acre-feet)
<br />
<br />Wain }'tar IIJiJtJ JUG') 191],\ 19f;.:; IfJ6G
<br />Califor1!.in
<br />Palo Verde Irrig. DisL 379 362 403 ,;73 3Ri
<br />~1etropolit3n Water
<br />Dist.____________ 1,029 ],0(,; 1,092 1,IS0 l,t21
<br />Yuma Project Rescr\',
<br />Diy._ "---------- 45 4, 48 46 4-8
<br />Imperial Irri~, Dist. 2.988 3,053 2,859 2,75(, 2.77R
<br />Coachella Valle\'
<br />Co. Water D~st,__.. 558 537 505 526 .t,'::-1-
<br />TotaL__________ 4.999 5,062 -1-,907 4,881 4.81B
<br />Ari':.ona
<br />Coloradu R. Indian
<br />Resen:atioll___ 178 1x2 1,9 17S 186
<br />Gila Project --------- 572 591 642 616 ~5.~
<br />Yuma Proj. VCl\ley
<br />Div,,______________ 182 Iii 176 182 162
<br />TutaL__________ 932 944 1,007 97(, 90-'
<br />:''irvada
<br />Pumping from Lake
<br />\1C3lL _ n_________ 2; 1(, 27 23 ,.
<br />.,'
<br />Grand TotaL __ 5,9)4 6,032 5,9-\-1 :;,8~O 5,74(,
<br />
<br />In addition to the users listed on Table 4,
<br />miscellaneous users divert from Colorado River
<br />or pump from wells adjacent to the mainstream.
<br />Gross diversions of these miscellaneous users in
<br />California, Arizona and Nevada have amounted
<br />to more than 100,000 acre-feet a vear for the
<br />past several years. .
<br />The Burcau of Reclamation releases warer at
<br />Hoover Dam to sarisfy requirements for the
<br />i\,lexican \Vater Treaty and sixreen separate
<br />agencies in the United States; thirteen of the
<br />agencies arc ,erved by diversions at Imperial
<br />Dam. Parker Dam, 148 miles upstream and
<br />
<br />24
<br />
<br />three days' flow time from Imperial Dam, is rhe
<br />nearest major rcgulating structure. j'dan,' factors
<br />arc involved in scheduling releases to meet an-
<br />ticipated downsrream requirements. The rare of
<br />flow at Imperial Dam is seldom rhe precise rate
<br />actually required owing ro changes in the
<br />weather and other factors, during the travei time
<br />from Parker Dam. Minor shortages can some-
<br />rimes be compensared for by increased deliveries
<br />on subsequent days. However, if conditions
<br />Ic"en rhe demand for water, rhe excess river
<br />flows which cannot he called back, must pass on
<br />as overdeli\'cries to Mexico. Imperial Reservoir.
<br />designed primarily for diversion purposes, has
<br />very little regulatory capacity. Plate 6 shows rhe
<br />periods of rime required for Parker Dam re-
<br />leases ro reach various agricultural areas.
<br />
<br />Deliveries to Mexico
<br />
<br />For rhe purpose of water salvage through
<br />reduction of excess deliveries to Mexico and
<br />through better control of deliveries to irrigared
<br />areas in the United Srates, the Bureau of Rec-
<br />lamation in January 1966 complered construc-
<br />rion of Senator \Vash Dam and Regulating Rcs-
<br />ervoir, on a tributan- wash in California
<br />upstream from ImperiaI'Dam. However, opera-
<br />tion was on a limited basis during the remainder
<br />of 1965-66.
<br />The dam is an carthfill embankment 94 feet
<br />high and 2,340 feer long. The dam and rhree
<br />dikes creare a reservoir with a capacity of
<br />13,800 acre-feet. The re\'ersible dual-purpose
<br />plant has a pumping capability of 990 cfs and
<br />generating capacity of 7,200 kilowatts.
<br />Operating procedure will have Senator Wash
<br />Pumping Plant commence pumping water from
<br />Imperial Reservoir to Senator \\lash Reservoir
<br />whenever surplus water reaches Imperial Res-
<br />en'oir. Concurrenth-, if Senator \Vash Reser-
<br />voir contains more than .i ,000 acre-feet of
<br />water, releases from Parker Dam will be re-
<br />duced. As a precautionary measure, because of
<br />the three days required for Parker releases to
<br />reach Imperial Dam, releases from Parker Dam
<br />will not be reduced if Senaror \\lash Reservoir
<br />contains less than 5,000 acre-feet. If the avail-
<br />able rivcr flow to Imperial Dam is less than
<br />water requirements, the flow will be augmented
<br />bv releases from Senator \Vash Resen'oir.
<br />. The project, the first of its type to be built
<br />on rhe Lower Colorado River, will gi\'e rhe
<br />
<br />\'I
<br />
<br />i~
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