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001971 production -- particularly vegetable production -- diminished and the irrigated land in the Mexicali Valley became significantly more saline. This led to protests by Mexico and a series of interim agreements to control the salinity of Colorado River water delivered to Mexico under the Treaty. In 1965, Minute 218 (effectively an amendment) to the United States Mexico Treaty) was approved. It required the United States to bypass around Morelos Dam part of the extremely saline (6,000 mg/I TDS) agricultural drainage from the Wellton- Mohawk district in Arizona. Negotiations for a permanent resolution of the salinity issue continued between 1965 and 1972. In 1973, an agreement was reached restricting the allowable increase in salinity between Imperial Dam and, the Northerly International Boundary to 115 ppm + 30 ppm. The agreement was embodied in Minute 242 to the Treaty. To achieve the standards of Minute 242, all of the agricultural drainage from the Wellton-Mohawk area would have to be desalted or else bypassed around Morelos Dam without being credited against the Treaty delivery obligation. Bypassing flows without charge against the 1.5 million acre-feet per year Treaty delivery obligation resulted in additional water being released from Hoover Dam to meet the increased total delivery to Mexico. This additional Hoover Dam release could decrease the amount of water available to US water users in a serious drought. The Bypass Drain was constructed pursuant to Minute 242 to carry any untreated and bypassed Wellton-Mohawk drainage water and the salt-water waste stream from the Yuma Desalting Plant to an acceptable terminal location. The 'Bypass Drain began operating in 1977, and has carried the untreated brackish agricultural drainage water since then. This delivery of brackish agricultural drain waters now supports an area of open water and wetlands in the Cienega de Santa Clara that is similar to areas of the historic Delta. The Bypass Drain now carries about 120,000 acre-feet per year of brackish water. It has a conveyance capacity of 300 cubic feet per second (210,000 acre-feet per year). If deliverY of additional Yuma Area agricultural drainage water to Mexico for use in the Delta was appropriate, the unused capacity of the Bypass Drain could be used for that purpose. The legal and institutional precedent for delivering brackish water to the Delta through the Bypass Drain without charge against Mexico's Treaty entitlement, can be found in Minute 242. The two nations would need to determine jointly that such a program is in their best interest. However, it must be recognized that users in the US would forgo opportunities to put the water to use.