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. 1"'., ., iUl.-t added subsequently, salinity is expected to then return to or below the criteria level. Periodic salinity increases above the criteria as a result of low reservoir conditions or periods of below long-time average river flow would also be acceptable within the standards, Return to normal conditions is expected to cause salinity concentrations to return to or below the criteria level. Salinity Control for Mexico During the year, the Bureau of Reclamation worked on engineering plans and specifications for the 104-million-gallon per day desalting plant and the other facilities and measures necessary to implement the 1973 agreement with Mexico on Colorado River salinity (Minute No. 242 of the International Boundary and Water Commission). The desalting plant and other measures were authorized by Title I of P.L. 93-320, which is described in the Board's 1974 Annual Report. The estimated costs for the Title I facilities have increased substantially since passage of P.L 93-320, when the costs were estimated to be $155.5 million. The Bureau of Reclamation's current cost esitmates for the facilities as of October 1975, is $269 million. This increase is due to inflation in construction costs and changes in design. This estimate could change depending upon final design and bids received for construction, Of special interest to California is the provision in Title I for constructing a new concrete-lined canal to replace the first 49 miles of the Coachella Canal. The United States will be entitled to temporary use of a quantity of water equal to the quantity conserved by the new canal for the purpose of meeting the salinity control objectives of Minute No, 242. Seepage water from the present 8 T---_ I :--____ I , I , I , I I I N I I I \ e Carson City canal has created a fish and wildlife habitat which will be sharply reduced by constructing the lined canal, and the Department of the Interior's Solicitor's office has held that these habitat losses must be mitigated in accordance with federal law, Accordingly, an ad hoc committee was establised to advise the Bureau of Reclamation on fish and wildlife mitigation measures that would be acceptable to both the fish and game agencies and to the concerned water districts. The Colorado River Board is represented on the committee. During the year, the ad hoc committee developed several mitigation measures which will be incorporated into a program for consideration by the Bureau of Reclamation. "\ Colorado River Basin Salinity Control Program , "" The Bureau of Reclamation continued its planning studies and investigations during 1975 on the four salinity control units authorized for construction by Title II of P.L. 93-320: Paradox Valley Unit, Colorado; Grand Valley Unit, Colorado; Crystal Geyser Unit, Utah; and Las Vegas Wash Unit, Nevada. The Bureau also continued its planning studies on the twelve potential salinity control studies specified in P.L. 93-320, The Bureau's studies were reported to be on schedule for completion of Definite Plan Reports for each of the four authorized units from July to October 1976, and for the preparation of a draft environmental impact statement on the program by the spring of 1976. Better scheduling of irrigation water to irrigators is expected to be a major tool in reducing the pickup of dissolved salts in the Colorado River Basin, The Bureau's program to accomplish this scheduling, called Irrigation Management Services, has been initiated in each of the authorized and potential project areas \:'Vherein irrigation is believed to contribute to salt pickup. During 1975, only a small fraction of the irrigated lands received the Irrigation Management Services, but the Bureau Los Angeles ~. E v \ \ \ \ (} -1.( /,p C San Diegoe