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'I ,. I I I I I I. I I I I I I I I I I I Pr02ress on u.s. Measures Provided for in Public Law 93-320 Beginning in late 1995, Mexico raised objections to peaks in salinity at the Northerly International Boundary (NIB) and to the salinity levels in waters delivered at the land boundary. The International Boundary and Water Commission, United States and Mexico, is addressing these matters through an International Task Force arrangement involving the federal water agencies of each country. The effort is for adjustments in operational practices at those periods where high salinity is a significant problem for Mexico. Mexico utilizes the treaty waters diverted at Morelos Dam for irrigation and domestic uses in the Mexicali Valley and conveys some of these waters via aqueduct to Tecate and Tijuana. Mexico's concern with an occasional salinity peak comes at those times when Mexico's water delivery demands are low. Beginning in early 1995, the International Task Force exchanged information regarding operations in the United States and Mexico. Salinity readings during 1998 indicate insignificant peaks at this delivery point. Mexico utilizes some ofthe NIB delivered waters along with water from wells near San Luis, Sonora J~~ ~~!lK!~~_~~aip~g~_ ~l!~e!~u!hat" the United States continues to deliver at the Southerly Land Boundary (SLB). Mexico uses this combInatIon of waters to Imgate 93,86(f acres'ffi -the area onlie Mexicali Valley in Sonora known as the Left Bank unit. Mexico is concerned over reduced crop yields and deteriorating soil quality and increased ground water salinity. In this case also, the International Task Force met several times to exchange information on United States operations and Mexico's management of the delivered waters. Mexico, in this respect, requested that all its treaty deliveries be made at the NIB. This proposal was not practical to the United States in that the United States is not able to prevent all these drainage waters from discharge to Mexico at the SLB and continues to have the right to make these deliveries as part of the treaty volume. Further, this would require release of stored water in the United States that is fully appropriated. Finally, there is the need to better understand the problem in the Mexican irrigation system and all the factors that influence increasing soil and groundwater salinity and lower crop yields. As a matter of cooperation in the near term, the International Task Force has narrowed the perceived effects to a period of four months of the year and examined scenarios of actions in each country that may be carried out to ameliorate salinity peaks during those periods. The two sides are soon expected to complete internal consultations on feasible alternatives. The United States shall continue to meet its legal obligations as described in Minute 242 by continuing to make the land boundary deliveries with the salinity in the waters customarily delivered at that point. The Yuma Desalting Plant (YDP) has been off-line since the first part of 1993, when the concrete lining of the Wellton-Mohawk drainage canal was damaged by flood waters from the Gila River. The damages were repaired. During 1998, the YDP continued to be on standby status while the U.S. Bureau of Reclamation reviewed alternatives for complying with the salinity differ~ntial. Groundwater Point 5 of Minute No. 242 provides that: 6