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-" G ,-; n .1 ""V Water Quality Salinity remains as one of the major problems facing the Colorado River Basin states. Colorado River Salinity Standards About six months after submission by all seven of the Colorado River Basin states to the Environmental Protection Agency (EP A) of the state-adopted "Colorado River Salinity Standards, Including Numeric Criteria and a plan of Implementation for Salinity Control", the EPA approved the standards on November 19, 1976. The salinity standards, which were reported on in the 1975 Annual Report, require the submission of an annual progress report to the Environmental Protection Agency by the States summarizing the results achieved by the salinity control program and the effect of other actions in the Basin having an influence on salinity. The Colorado River Basin Salinity Control Forum, through the Work Group, prepared the annual progress report. The Board's staff performed most of the engineering studies used in the report. The study found that the salinity at the three lower mainstem stations-Hoover, Parker, and Imperial Dams-for the period 1973 through 1975, are all below the established numeric criteria. High annual precipitation in the past few years which has resulted in increases in reservoir storage, coupled with a slower than projected rate of increased water use, account for the lower salinity levels. Although slightly behind schedule, three authorized federal salinity control units have received funding for construction. The Forum's plan of implementation for salinity control specifies a policy of no salt return from industrial dischargers whenever practicable. It was recognized that to implement this policy through the issuance of National Pollution Discharge Elimination System (NPDES) permits, further amplification of the no-salt-return policy was needed. The Work Group prepared and the Forum adopted "A Policy for Regulation of Salinity by NPDESPermits in the Colorado River Basin", July 21, 1976. The Enforcement Division of EPA found the policy failed to provide sufficient guidance for the preparation of effluent permits and recommended a new policy be developed. A special subcommittee of the Work Group and EPA representatives was appointed to prepare a revised policy document. .. ---- - .---. --------- N E v · Carson City Salinity Control for Mexico \ The Bureau of Reclamation continued its work on engineering plans and specifications for the desalting plant and other facilities and measures necessary to implement the 1973 agreement with Mexico on Colorado River salinity. The desalting plant and other measures were authorized by Title I of P.L. 93-320, and described in the Board's 1974 Annual Report. In order to reduce costs, the Bureau has reduced the size of the desalting plant from 104 million gallons per day of product water, as originally planned, to 96 million gallons per day. Due to inflation in construction costs and changes in design, the estimated cost for all Title I facilities, the desalting complex, the new 49-mile section of the Coachella Canal and the protective and regulatory groundwater well field, have increased substantially since passage of P.L. 93-320 in June of 1974. The amount authorized in P.L. 93-320 was $155 million, which is equivalent to a current indexed cost of $217 million. The cost estimates for the facilities, based on July 1976 prices, is $316 million. Brine waste from the desalting plant will be transported 51 miles to the Santa Clara Slough in Mexico via a concrete-lined extension of the Wellton-Mohawk Bypass Drain. , \. \ , '\ "\ C> "'1.( /' -I Los Angeles ~ 50, Die\-~ ~