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<br />130'1
<br />
<br />16. DISCUSSION OF UPPER BASIN SUMMARY.
<br />
<br />In the meantime, should the main river power projects in the Upper Basin
<br />be constructed to meet the power needs of the Lower Basin, some adjustment of
<br />rights, obligations and relations between the two basins, as defined in the
<br />Colorado River Compact, will became necessary in order to recognize the fact
<br />that evaporation losses fram such power reservoirs will replace and prevent an
<br />elJ.uivalent beneficial consumptive use of water in the Upper Basin, and to
<br />recognize the fact that the benefits of such Upper Basin power reservoirs,
<br />under the conditions above out] ined, will accrue to the Lower Basin.
<br />
<br />The Bureau of Reclamation should not assume, nor the Report infer, that
<br />''beneficial consumptive use of water" in the Upper Basin is permanently limited
<br />to 7,500,000 acre feet per annum. The fact that all projects listed in Report,
<br />if and when constructed, may result in depletions averaging 7,643,000 acre
<br />feet annually, or more, and may thereby exceed the 7,500,000 acre feet of
<br />water allocated by the Compact, should not be construed as being in excess of
<br />the rights of the Upper Basin, inasmuch as "further elJ.uitable apportionment
<br />of the beneficial uses of the waters of the Colorado River system unapportioned
<br />by paragraphs (a), (b) and (c) may be made *** at any time after Oct. 1, 1963,
<br />if and when either basin shall have reached its total beneficial consumptive
<br />use as set out in paragraphs (a) and (b)," namely 7,500,000 acre feet in the
<br />Upper Basin and 8,500,000 acre feet in the Lower Basin.
<br />
<br />17 . DISCUSSION OF ImlER BASIN SUMMARY
<br />
<br />The half-page: "Summary - Lower Basin," appearing at page 272 of the
<br />Repprt should be re-written and expanded. It purports to show that the
<br />depletions of projects (present, future and potential) in the Lower Basin,
<br />excluding the Gila River, are greater than the available water supply.
<br />
<br />Stating that, since the average annual virgin flow at Iaguna IBm is
<br />16,451,000 acre feet, 'when present and potential depletions in the Upper
<br />Basin average 7,500,000 acre feet a year, the average annual flow of the
<br />Colorado River at Iaguna Dam would be 9,331,000 acre feet, based on an esti-
<br />mated decrease in channel losses of 380,000 acre feet." The answer derived
<br />by subtracting 7,500,000 from 16,451,000 and adding 380,000 is 9,331,000, but
<br />that figure could not represent the flow at Iaguna L'e.m unless there were no
<br />depletions along the main river and its tributaries between Lee Ferry and
<br />Iaguna L'e.m. Instead, the 9,331,000 acre feet represents the virgin flows of
<br />the Little Colorado and Virgin Rivers, and the flow of the Colorado River
<br />after the assumed Upper Basin depletion, with allowances for conveyance
<br />losses between Lee Ferry and Iaguna D9Jn.
<br />
<br />In calculating the virgin flow at Iaguna Dam it is apparent that an
<br />allowance was made of 468,000 acre feet for virgin condition channel loss
<br />between Lee Ferry and Iaguna IBm, as follows:
<br />
<br />(25)
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