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Show CHAPTER XIII 221 of the water in the river at Imperial Dam delivered to United States users. The reject stream, which will be carried to the Gulf of California, initially will be approximately 43,000 acre-feet per year and is estimated to have a salinity of 9,600 p/m. This quantity will have to be replaced with better quality river water. G.2 Coachella Canal Lining It is anticipated that the new concrete-lined Coachella Canal of 49 miles in length will save approximately 130,000 acre-feet per year. This quantity will be available temporarily during a so-called "interim period" to the United States for substitution purposes through reduced deliveries to the Coachella Valley Water District. This will reduce the draft on storage to provide substitution waters to a level of 45,000 to 88,000 acre-feet per year. The interim period ceases when deliveries to California are reduced; i.e., when CAP deliveries begin. H. Benefits to United States The United States negotiators ascribed the following tangible benefits to the United States. The agreement eliminates the possibility of long years of controversy. It does not require any payments of monies to Mexico for any past damages. It is a "permanent solution" to the salinity problem. Mexico agreed to accept 140,000 acre-feet per year of their Treaty water right at the Arizona-Sonora boundary, which is largely drainage water with a higher salinity than that of the Colorado River. Although Mexico has accepted this water for years, there was no written agreement on Mexico's part to accept this water at this location until Minute No. 242 was signed. Although the United States has agreed to reduce the salinity of the Wellton-Mohawk drainage waters under the new agreement, other drainage waters below Imperial Dam will continue to be accepted by Mexico as part of the Treaty obligation. /. Position of Basin States It was the position of the Colorado River Basin States that Minute No. 242 was entered into on the basis of international comity and that the Basin States should not be expected to bear any greater burden as a result of the new agreement than that to be borne by the rest of the Nation. Therefore, they urged contemporaneous authorization of a Colorado River Basin Salinity Control Program and prompt construction of the desalter and the lining of the Coachella Canal. Their reason was that until that was done, the United States would continue to deliver 118,000 acre-feet per year to Mexico above the 1.5 maf Treaty obligation and the over-delivery would come from water supplies otherwise available to the Basin States. Furthermore, the Basin States urged that the replacement of all bypassed waters and the reject waters from the desalting plant should be the obligation of the United States because, if not replaced, there would be a permanent additional delivery to Mexico of 43,000 acre-feet per year in excess of the Treaty obligation of 1.5 maf/yr. I.I Well Field Shortly before negotiation of Minute No. 242, Mexico had constructed a well field within 1 to 5 miles of the southerly United States - Mexico boundary, south of Yuma, Arizona, capable of pumping approximately 160,000 acre-feet per year of ground water which originates in the United States. If unchecked, this would result in the loss of ground water by the United States. To protect against this, a limitation on the extent of Mexican ground-water pumping was necessary so as not to impact the United States water supplies and the United States would also have to resort to a protective pumping program. It further appeared that the combined pumping of the two governments, assuming the United States installed its own well field and no agreement is reached on ground water, would ultimately dry up the Yuma Valley Drains which delivers approximately 140,000 acre-feet per year to Mexico at San Luis so that the pumping of ground water in the United States would be required to maintain deliveries of this quantity of water to San Luis. |