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Salton Sea Water Management JEANINE JONES [, the ChieJ oj the Statewide Planning Branch c.fDwR's Division of Planning. -' In Janu?uy, Bulletin 160 Advisory Committee membe::s met at Imperial Ir- rigation District's office and toured the Salton Sea. The purpose .of the tour was to provide an'overview of resource man- agement issues as~;ociated with the sea: and to hear potentlal solutions to contro1-" the sea's salinity and elevation. Advisory ,Committee member DOl) Cox, president of IID's Boa,d of Directors, also is president of the Salton Sea Authority. The Authority was created by IID, Coachella Valley Wa- ter District. Imperial County, and River- side County to provide a forum for work- ing on Salton Sea issues. . Setting The present-da:r Salton Sea was formed in 1905. when Colorado River wa- ter flowed through a break in a canal that had been constructed iri Mextco to divert the river's flow to' agricultural lands in the J Imperial Valley. UnW that break was re- "paired in 1907, the full flow of the river was diverted into ':he Sci1ton Sink, a ' structural trough whose lowest point is about 278 feet below sea level. Within geologic time the Colorado River's course has altered severel times. 'At times, the river discharged 1<) the Gulf of California as it does today. At other times it flowed into the Salton ~ink. Lake CahuUla. the most recent of se,'eral prehistoric lakes to - , have occupied the Salton Sink, dried up some 300 years ago. (CVWD's Lake Ca- huilla', the terminal reservoir for the Coachella Brand:, of the All-American Ca- nal, was named after the prehistoric lake.) , . '. , / / The Salton Sea is the largest lake lo- cated entirely withtii California. with a" volume of about 7.7 maf. The sea occu- pies a closed drainage basin - if there were no inflows to maintain lake levels, 'its waters would evaporate as did those of prehistoric Lake CahuUla. The area's- average annual precipitation is 3 inches or less. while average annual evapora- tion is in excess of 5 feet. The sea re- ceives over 1 maf annually of inflow. pri- marily from agricu~tural drainage. The largest sources of inflow (about 80 percent of the total) are the New and Alamo rivers which drain agricultural lands in the Mextcali and Imperial val- leys and flow into the sea's souther)]. :end. The New River also carries un- treated or rninimal1y treated wastewater from the Mextcali area (in Mextco) into the sea, although these flows are diluted by the much greater quantities of agri- cultural dram water entering the river. In 1924 President Coolidge issued an executive order withdrawing seabed lands lying below elevation -244 to s,erve as a repository- for agricultural drainage water. That order was expanded in 1928 to lands below elevation -22,0. Today, in addition to receiving agricultural drain- age flows and stormwater flows, the sea supports water-based recreational activi- ties and has had an abundant and pop- ular corvina fishery. ' During the 1950s. the highest per cap- ita sport fishing catches ~n California were from the Salton Sea. Over the years. concerns about the sea's sali-riity have, been voiced in the context of maintairling , this recr;~ational fishery with introduced species able to tolerate high salinities. The sea also provide~ important win- tering habitat for many species of / , 2