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Chapter 4 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 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. TITLE I PROGRAM Title I of the Colorado River Basin Salinity Control Act of 1974 (Public Law 93-320) provided the means to comply with the obligations made by the United States to Mexico, including a desalting plant and a bypass channel. These facilities will enable the United States to deliver water to Mexico with an average salinity concentration no greater than 115 ppm +/- 30 ppm (United States count) over the annual average salinity concentration of the Colorado River water at Imperial Dam. Coachella Canal Lining To assist in meeting the salinity control objectives 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 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 Well ton-Mohawk irrigation drainage waters and for the reject stream from the Yuma Desalting Plant. The interim period began when construction was completed in 1982 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 California. Protective and Regulatory Pumping Section 103(a) of Public Law 93-320 authorized the construction, operation, and maintenance of the Protective and Regulatory Pumping Unit (PRPU) by Reclamation to manage and conserve United States ground water for the benefit of the United States and for delivery to Mexico. The PRPU is located in a zone 5 miles wide along the Southerly International Boundary between Arizona and Sonora. The Protective and Regulatory Pumping Unit was developed to intercept part of the ground-water underflow that moves southward from the Yuma Mesa in the United States into Mexico. Before the PRPU was constructed, this underflow was increasing because of ground-water pumping in the Sonora Mesa Well Field, immediately south of the Southerly International Boundary in Mexico. The Colorado River Basin States expressed their concern about the pumping in their July 1973 letter to the President. 40