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REGULATORS FOCUS ON DISTRICT DRAINS A combination of factors has increased attention on drains in Imperial Valley and the quality of water those drains deliver to Salton Sea. Selenium studies are being conduct- ed by the U.S. Bureau of Reclamation (USBR) and U.S. Fish and Wildlife Service. The state's Regional Water Quality Control Board (RWQCB) has been monitoring the con- tents of drain water to establish baseline data on chemical concentrations in drains. Selenium studies for the USBR by Jim Setmire, research specialist in selenium, have identified some drains with high concentrations of the element. These levels, while above acceptable levels set by the Environmental Protection Agency (EPA), are not near levels which have caused harm to wild fowl in other areas. And levels found in Salton Sea water are well below those EPA thresholds. The District is cooperating fully with these studies to use this information to develop the most cost effective plan to best manage drain water. During 1994 the District worked closely with the RWQCB to find a workable plan to sample over 1,000 drain sites. This sampling has confirmed the theory that pesticides and herbicides are attached to small silt particles that are suspended in drain water. Because the Valley's drainage area is a closed system, this silt accumulates in New and Alamo Rivers and Salton Sea. The RWQCB has retained researchers from the University of California at Davis to continue detailed sampling and analysis at 60 spe- cific sites to develop more data regarding the relationship of silt particles, attached chemicals and how those chemicals concentrate. As a proactive step to develop this data, the District has implemented a Drain Water Quality Improvement Program. District staff have begun to monitor eight sites for data and develop a list of on-farm Best Management Practices (BMPs) to reduce sediment loads leaving fields. Two of the B/I'\Ps will be selected as pilot programs. The engineer- ing firm of Jones and Stokes, with input from farmers and District staff, will develop the programs. The vast enclosed drainage area in Imperial Valley is an ideal laboratory for these studies and the District is once auain at the forefront of research into drainage issues. The proactive approach will hopefully yield cost effective ways to deal with these drainage issues and also applicable solutions for other irrigation systems. 11