<br />0004<17
<br />
<br />-18-
<br />
<br />Colorado says that export di vers~ons of existing enterprises in Colorado,
<br />as they are now constructed and will function in a year of normal climate,
<br />will average 135,000 acre feet annually; and that detailed estimates by
<br />individual projects appear in the statement submitted by Colorado at the
<br />meeting held in Reno, Nevada, July 20, 1944. A comparAble figure for existing
<br />exportations in Utah under normal conditions appears to be 79,000 acre feet,
<br />making a total for the Upper. Basin of 214,000 acre feet annually.
<br />
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<br />
<br />34. Together, the existing depletions in the Upper Basin, resulting
<br />from water consumption incident to the il"rigation of lands within the na-
<br />tural basin and frcm export diversions for use outside the natural basin,
<br />exclusive of allowances for projeots authorized but not constructed 'and
<br />enterprises not yet comp let ed, as e stiooted by Co lorado engineers for the
<br />average year of drouth cycles and normal periOds, may be summarized as
<br />followsl
<br />
<br />Drouth Cyc Ie
<br />
<br />Normal Period
<br />
<br />Irrigation Consumption in Upper Basin
<br />
<br />1,812.000
<br />
<br />2,013.000
<br />
<br />Export Diversions out of Natural Basin
<br />
<br />168 .000
<br />
<br />214.000
<br />
<br />Total Existing Upper Basin Depletions
<br />
<br />1,980.000
<br />
<br />2,227 ,000 ..
<br />
<br />.. The comparable figure derived from the Report may
<br />approximate 2,129,000 aore feet.
<br />
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<br />
<br />35. In the LOW3r Basin, the Report includes depletions within the
<br />natural basin with exportations for use outside the natural basin, the
<br />sum of the two together with evaporation losses from ma.in-stem reservoirs
<br />being 4,497,000 acre feet annually. Total consumption incident to the
<br />irrigation of 890,200 acres of land within the natural basin (in Arizona,
<br />Nevada, New I1exico and Utah) is estiJnated in the Report at 1,591,000 a.cre
<br />feet annually; diversions from the River for the irrigation of 460.900
<br />acres of land in California are estimated at 2,193,000 acre feet amual1y;
<br />and evaporation Losses from main-stem reservoirs are ~stimated at 713,000
<br />acre feet annually. Independent estimates by Colorado engineers indicate
<br />that depletions of existing projeots in the Lower Basin, under normal
<br />climatic conditions, will average 5,670,000 aCre feet annually, exclusive
<br />of allomnces for irri gable lands of existing enterprises that have not
<br />been irr igated up to the present time. Eltport diversions for use outside
<br />the natural basin below Lee Ferry are given in the Report at 2,193,000
<br />acre feet annually., and are estimated from diversion data by Colorado en-
<br />gineers at 2,700,000 acre feet amlUally. Evaporation losses from main-
<br />stem reservoirs appear in the Report as 713,000 acre feet amually, and
<br />are estimated by ColoradO engineers (froin streamflow records) at 800,000
<br />aore feet annually. Since the estimates of its engineers, with respect
<br />to existing depletions in the Lower Basin, are substantially greater than
<br />the estiJnates appearing in the Report, ColoradO suggests that the BureaU
<br />of Reale.mation.re-exe.mine its calculations; and, in the event the revised
<br />estimates are not materially increased, that the detailed information
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