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USBRIMWD SALINITY MANAGEMENT STUDY FINAL REPORT systems. A CALFED Bay-Delta solution could lower SWP salinity by 100 mg/L and reduce its short-term variability. e W CJl ....;I t+;;. Local salinity sources include naturally occurring salts, salts added by urban water users, infiltration of brackish groundwater into sewers, irrigated agricultural and confined anim waste management practices. Urban use contributions to wastewater range from 250 to 400 mg/L or more in some locations. SALINITY MANAGEMENT POLICY STATEMENT AND ACTION PLAN This report proposes a comprehensive salinity management policy for Metropolitan and a corresponding Action Plan. The Action Plan consists offour basic components: CJ Imported water source control actions CJ Distribution system salinity management actions CJ Collaborative actions with other agencies CJ Local actions to protect groundwater and recycled water supplies It is expected that the adopted action plan will be revisited and updated periodically as clarity arises in a number of critical areas including the CALFED Bay-Delta Plan, Californias Colorado River Water Supply Plan, wheeling practices, Stage II disinfection by-products rules e under the Safe Drinking Water Act Amendments, and operational experience gained throUghr~"I~%"11 implementation. The first major update is recommended to occur in 2004 when the Inland ~Il Feeder becomes operational or sooner if a significant unanticipated change in controlling JJL conditions occurs. RESOURCE LIMITATIONS ON BLENDING COLORADO RIVER WATER SALINITY The foundation of Metropolitans draft Action Plan is an imported water salinity target of 500 to 550 mg/L. Managing imported water through blending would be supplemented by source control in the two imported water river systems, storage and exchange operations along the CRA, and a CALFED solution. Blending in Metropolitans system is achieved by curtailing delivery of higher-salinity CRA water and substituting it with comparable amounts of lower-salinity SWP water. Annual changes in imported water supply availability and salinity concentrations greatly affect Metropolitans ability to achieve the target through blending. For example, above-normal runoff in 1998 has provided unusually favorable conditions resulting in lower than target salinity levels in some months. In contrast, under conditions like the 1977 drought, e BOOKMAN-EDMONSTON ENGINEERING, INC. ES-2 O:\LOCALRESIANDYSlSALTNITYVUNE1998IEXECSUMDOC Last printed07/2OJ98 9:23 AM Executive Summary