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..... (X) U1 ~ (Continued from page 1.) tons of salt annually from the river system. Projections of future salinity conditions used the average of 15 sequences of histori- cal hydrology (1906-1983) as a data base and current (1987) depletion projections developed jointly by Reclamation and the Forum, The salinity at Imperial Dam is projected to reach about 960 mg/L by the year 2010, Figure 1 provides an historical perspective in addition to the numeric stand- ard and the projections at Imperial Dam. It is readily apparent that without the recommended con- trols, the salinity at Imperial Dam Is expected to increase signifi- cantly over the next eight years due in part to expected normal hydrologic conditions, Using the salinity projections at Imperial Dam, salt load reductions required to reduce projected TDS (total dis- solved solids) levels to the numeric criteria of p 879 mg/L are estimated to be about 1 million tons per year by the year 2010 and is referred to as the program objective. Figure 1 also shows how the implementation plan meets the numeric criteria, MAJOR FINDINGS The recommended plan is expected to fully satisfy salt load reduction objectives and program goals, maintaining salinity levels at Imperial Dam at or below 879 mg/L. The recommended plan's implementation schedule is shown on table 1. This analysis is based on cur- rent data (January 1987), Annual review Is required to update project data. check progress against program objectives, and Salinity Projections at Imperial Dam with and without further controls S a I i n i t Y 1000 950 900 850 800 750 Standard Projections -- i: j :" 700 m . . 650 -\ ' g 600 / L 550 1941 50 60 * Provisional thru November \ \ .\ \ .' ;' \ .~ , * 70 80 Years 90 2010 00 Fig 1, Salinity projections with & without further controls validate that investment level assumptions of approximately $560 million will satisfy program objectives. As evidenced by past pro- gram activities, long lead times are required for project plan- ning and implementation, and con- struction costs will continue to increase, To minimize program costs and to avoid increased infla- tion expenses, program planning, implementation schedules, and funding levels should be consis- tent with the recommended plan. Although high flows for the past few years have temporarily lowered salinity levels in the sys- tem, construction should not be delayed. Any delay would impact program continuity and increase overall program costs, . The recommended plan will fully satisfy the remaining salt load reduction objective of removing about 1 million tons per year by 2010 and the program goal of 2 maintaining salinity at or below 879 mg/L at Imperial Dam. . Total remaining construction cost for the program is now projected to be about $560 million. . In order to meet the program objectives and goals beyond the next decade, to minimize Lower Basin interest costs, and to maintain program con- tinuity, construction of several new projects as specified in the implementa- tion plan needs to be initiated in the next 4 years. The $560 million investment level appears to best satisfy the remaining long-term requirements at least invest- ment costs, . To meet salt load reduction objectives, it is necessary to