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w m o .;;.. direct impact on the Basin states, The solution recommended was divided into two stages--interim and permanent, The following are the principal elements of the recommended interim solution: 1. Continuation of deliver~ of a total of some 120,000 acre-feet of water from Yuma Mesa pumplnf and Imperial Dam storage in substi- ~ution for a like amount of We lton-Mohawk return flows, as under Minute No. 241, until water from Coachella salvage becomes avail~ble, Qr the permanent solution can be implemented. 2. Relocation and lining of a portion of the Coachella Canal in Qalifornia under a cost-sharing arrangement between the Federal ~vernment and the Coachella Valley County Irrigation District tp slalva e some 130,000 acre-feet of water er. ear for tem orar ~deral use in an interim solution, , ~. Steps to reduce the irrigated acreage at Wellton-Mohawk to as n'ear 60,000 acres as proves practi ca 1 under an incentive program. 4, Maximum practical efforts to improve Wellton-Mohawk District d,nfarm irrigation efficiency, as worked out cooperatively among the De artments of the Interior and A riculture, the Environmental rotectlon Agency, and the D strict, The recommended ermanent solution is desaltin of Wellton-Mohawk draina by aem rane process esa lti ng p ant to be in fu 1 operation by Under ,the assumptions of 60,000 acres under irrigation, at a District efficiency of 63 percent, it was estimated that Wellton-Mohawk draina~e would 'average 175,000 acre-feet with a salinity of 3,050 mg/l per year by 1980. . A membrane process desalting plant would be designed for the pro- jected 1980 conditions, although the facilities would become operational in 1978. For the first two years of its operation, the desalting plant would ,be slightly underdesigned unless greater Wellton-Mohawk efficiency were achieved than estimated at the time of design. The plant would be desigrted using today's technology which is capable of recovering 70 per- cent df the feed water at 280 parts per million salinity. The capital and operating costs of the desalting plant would vary substantially with the. amount of water to be desalted and the method of brine disposal. Every effort would be made to keep the capital and operating costs to a minimum. The result of the above-described interim and permanent actions would be that ~y 1978 the salinity of Wellton-Mohawk District drainage water would no longer affect Mexico, With the removal of the effects of Wellton- Mohaw~ drainage, Mexico should be able to use without difficulty the drainage, salvage, and other such waters as the United States has been deliv~ring and expects to deliver in the future as a part of Mexico's treaty allotment. .' 6 ~~ . ~ ,:;'",- .' ~'d. .~;...~~,-. , , ~,t :l: "y -1 , J;~ ,~,~~~