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DEPARTMENT OF STATE WASHINGTON LIMITED OFFICIAL USE NOV 2 1964 Dear Mr. Secretary: Since my letter of August 5 there have been a number of developments in our attempt to resolve the Colorado River salinity problem with Mexico. Most significantly, the Government of Mexico concluded that it could not accept installation of a tile drainage system at Wellton-Mohawk as the "permanent and effective solution" contemplated in the Presidential Communiques. Based on estimates by Interior Department engineers that the tile drain effluent may have a salinity of 4-5,000 ppm, Mexican engineers estimate that the salinity of the water reaching Mexico would at times be higher than 1,500 ppm. Mexico, therefore, proposed, through its Commissioner, reconsideration of a "by-pass charnel" solution. The Department authorized Commissioner Friedkin again to explore the feasibility of a solution based on a by-pass channel. I understand that he and Mr. Sayre reported to you on these developments on October 6, 1964. There followed further consultations with the Bureau of Reclamation concerning a "by-pass channel" solution which would effect a 1.5 salt balance index in the Wellton-Mohawk drainage delivered above Morelos Dam, as initially proposed to Mexico in July. The basic points were discussed with the Bureau of Reclamation, and Commissioner Dominy gave his affirmative advice on October 8. Through consultation with the Bureau, Commissioner Friedkin and the two Departments developed "Essential Provisions of a Minute between the U.S. and Mexico." The Interior Department notified the State Department on October 28 of its approval of the terms in principle. The Honorable Stewart L. Udall, Secretary of the Interior. U.S. DEPT. OF INTERIOR RECEIVED NOV 2 11 03 AM "64 IMMEDIATED OFFFICE OF THE SECRETARYEpson Perfection 4870 Photo, 400 dpi, 8 bit, 13,103,616 byte