State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Imperial Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants : the United States of America and State of Nevada, interveners : State of Utah and State of New Mexico, impleaded defendants : report / Simon H. Rifkind, special master

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186 This language clearly states that California is limited to 4,400,000 acre-feet, not of water, but of the consumptive use of water measured by diversions less return flow. Congress did not purport in Section 4(a) to limit California to a portion of the water flowing at Lee Ferry or stored in Lake Mead. While Congress could have limited California to 4,400,000 acre-feet of consumptive use out of a body of water at some point along the River, no such point is specified in Section 4(a), and the more natural reading of the language is that Congress limited California to a portion of the total amount of consumptive uses made of mainstream water in the United States each year. The most rational way to measure consumptive use of water as defined in Section 4(a) is to measure diversions made from the mainstream and to measure or calculate how much of the diverted water returns to the mainstream. Segregating water at Lee Ferry or Lake Mead cannot contribute to the measurement of "diversions less returns to the river." And the consistent administrative interpretation of Section 4(a) supports the conclusion that the limitation on California is not to be measured at Lee Ferry or at Lake Mead, but rather at points of diversion. All of the water delivery contracts entered into by the Secretary of the Interior on behalf of the United States, including the contracts with California users which incorporate the Section 4(a) limitation and the contracts with other states which are correlated to it, provide that the delivery obligation under each contract shall be measured at the points of diversion. For the reasons stated, I interpret Section 4(a) as limiting California annually to 4,400,000 acre-feet of consumptive use of mainstream water out of the first 7,500,000 acre-feet of consumptive use annually of such water in Arizona, California and Nevada. Consumptive use is to be measured by diversions at each diversion point on the mainstream less returns to the mainstream, meas-