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<br />The lining of approximately 49 miles of the Coachella Canal <br />~ in California will decrease the amount of water lost through see- <br />~ page but will allow this salvaged water to be temporarily used to <br />C) meet the salinity control objectives of Minute No. 242. ThIs <br />~ temporary use will end when California has less water than <br />allowed under the Boulder Canyon Project Act and the Supreme <br />Court decision in Arizona against California. The amount of water <br />in question is approximatley 132,000 acre-feet per year. The <br />canal was operating in laLe 1980 with only the telemetering <br />towers and wildlife mitigation aspects remaining. <br /> <br />The acreage retirement and irrigatIon efficiency improvement <br />programs are aimed at reducing the irrigation return flows and <br />thus reduce the operating cost of the Yuma DesaltIng Plant. In <br />addition, it would also insure that water use does not exceed the <br />District's annual Colorado River allocation of 300,000 acre- <br />feet. Authorization for the Well ton-Mohawk Project was under the <br />1947 Gila Reauthorization Act which included 75,000 acres for <br />irrigation. However, In 1973, about 20 years after the first <br />delivery of Colorado RIver water, only 64,000 acres were being <br />irrigated. The retirement of 10,000 acres, as proposed in this <br />Act, would not result in land being taken out of production. The <br />irrigation efficiency improvement programs included upgrading <br />some gravity systems, conversion of some areas to pressure <br />systems, and an irrigation management and schedulIng program. <br /> <br />The development of the well field In Arizona is in response <br />to the completion of the San Luis Mesa .Well Field by Mexico in <br />1972. This well field is located immediately south of the inter- <br />national boundary separating Arizona from Sonora, Mexico. The <br />Mexican pumping was withdrawIng water from the United States at <br />an annual average rate of 107,000 acre-feet. The MexIcan pump- <br />ing, along with the Yuma Mesa pumping, was rapidly lowering the <br />water table in this area. The lower water table was causing a <br />significant decrease in flows from the Yuma Main Drain. It was <br />felt that continued pumping by Mexico would eventually eliminate <br />ali drain flows whIch were estimated at approximately 125,000 <br />acre-feet. The United States has an obligation to Mexico of <br />140,000 acre-feet of water at the Southerly International <br />Boundary. The historical difference between 140,000 acre-feet <br />and 125,000 acre-feet was made up of wasteway flows. The pro- <br />posed well field (Protective and Regulatory Pumping Unit Well <br />Field) is limited by Minute No. 242 to 16D,000 acre-feet an- <br />nually. The San Luis Mesa Field is also limIted to this <br />quantity. It is estimated that 125,000 acre-feet of this water <br />would be used to meet the United States' obligation to Mexico and <br />the remaining 35,000 acre-feet will be available for use in the <br />United States. Of the projected 35 wells, 14 have been <br />completed, 7 have been drilled but not outfitted and 14 are still <br />in the planning stage as of March 1981. <br /> <br />The two add i t ional feiltures of T it Ie I that are of relative <br />imporLance are the feasibility study for reject water and the <br /> <br />3 <br />