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Chapter 7 Colorado River Basin Salinity Control Program Title I of the Colorado River Basin Salinity Control Act, Public Law 93-320, authorized the Secretary of the Interior to proceed with a pro- gram of works of improvement for the enhance- ment and protection of the quality of water available in the Colorado River for use in the United States and the Republic of Mexico. Title I enables the United States to comply with its obligation under the agreement with Mexico of August 30,1973 (Minute No. 242 of the Interna- tional Boundary and Water Commission, United States and Mexico), which was concluded pur- suant to the Treaty of February 3, 1944 (TS 994). Title II of the Colorado River Basin Salinity Con- trol Act, Public Law 93-320, of June 24, 1974, as amended by Public Law 98-569 of October 30, 1984, directs the Secretary of the Interior, com- mencing on January 1, 1975, and every 2 years thereafter, to submit simultaneously to the President, the Congress, and the Advisory Council, a report on the Colorado River Salinity Control Program covering the progress of investigation, planning, and construction of sali- nity control units for the 2 previous fiscal years. The report is to include the effectiveness of the units, anticipated work to be accomplished to meet the objectives of Title II with emphasis on the needs during the 5 years immediately following the date of each report, and any special problems that may be impeding progress in attaining an effective salinity control program. Title II also provides that this report may be included in the biennial Quality of Water, Colorado River Basin, Progress Report. Figure 5 on the following page shows the location of the Title II program study areas for both the Department of the Interior and the Department of Agriculture. TITLE I PROGRAM Title I of the Colorado River Basin Salinity Control Act of 1974 (Public Law 93-320) pro- videdthe means to comply with the obligations made by the United States to Mexico which included as major features a desalting plant and bypass channel. These facilities will enable the United States to deliver water to Mexico with an average salinity no greater than 115 ppm + 30 ppm (United States count) over the annual average salinity of the Colorado River water at Imperial Dam. Coachella Canal lining (Reclamation> To assist in meeting the salinity control objec- tives of Title I, the Secretary of the Interior was authorized to construct a concrete-lined canal or to line the unlined initial 49 miles of the Coachella Canal. The act required that a repay- ment contract be executed with the Coachella Valley Water District for partial repayment of the cost of the work over a 40-year period. An estimated 141,000 acre-feet of Colorado River water were lost each year through seepage from this reach of the canal. It is estimated that the lined canal will reduce seepage losses to 9,000 acre-feet per year, resulting in an annual savings of 132,000 acre-feet. The seepage losses saved are to be used for an interim period to substitute for the bypassed Wellton-Mohawk drainage waters and for the reject stream from the desalting plant. The interim period begins on completion of construction and ends the first year that the Secretary of the Interior delivers to California less mainstream Colorado River water than requested by California agencies and federal establishments with water rights in