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<br />PLAN FORMULATION <br /> <br />A number of salinity control alternatives for the Palo Verde subarea are <br />being considered in the plan formulation process. Basically, the alternative <br />studies consist of analyzing the effect that various action plans would have <br />on reducing salt contribution from the area. <br /> <br />Alternative plans for meeting the objectives of the study are evaluated on an <br />appraisal level to determine if they meet four tests listed in the Principles <br />and Standards to identify viable plans. These four tests include completeness, <br />effectiveness, efficiency, and acceptability. Briefly, the four tests can be <br />defined as follows: (1) completeness is the extent to which an alternative <br />plan provides and accounts for necessary investments or other actions to <br />ensure the realization of the planned effects, (2) effectiveness is the <br />extent to which an alternative alleviates the specified problem and achieves <br />the desired results, (3) efficiency is the extent to which an alternative is <br />cost-effective, and (4) acceptability is the workability and viability of the <br />alternative in respect to acceptance by the public and adherence to existing <br />laws and regulations. <br /> <br />Alternative plans which pass all four tests become candidate plans and are <br />subject to much more detailed examination. The next step in the plan selection <br />process entails subjecting each candidate plan to an analysis under each of <br />four accounts identified in the Principles and Standards. These four accounts <br />include (1) NED (National Economic Development), EQ (Environmental Quality), <br />(3) RED (Regional Economic Development), and (4) OSE (Other Social Effects). <br />It is from these candidate plans and the four account analysis that the <br />recommended plan is selected. In addition, primary importance in the CRWQIP <br />salinity investigations is the cost-effective criteria or the estimated cost <br />per milligram per liter of reducing the salinity contribution to the Colorado <br />River from the project area. <br /> <br />Because the Palo Verde subarea was shown to be causing most of the District's <br />salt discharge, the preliminary project evaluation discussed in this report <br />has been confined to that subarea. <br /> <br />The Palo Verde subarea lies in the southwest corner of the District, adjacent <br />to the mesa. It is approximately 11-1/2 miles long and 3-1/2 miles wide at <br />its widest point and contains a gross area of approximately 12,550 acres. <br />The Palo Verde Outfall Drain forms half of its eastern boundary, separating <br />much of the subarea from adjacent subareas. About 10,300 acres are irrigated <br />in the area. <br /> <br />The Bookman-Edmonston report estimated that in 1974, the onfarm irrigation <br />efficiency was 42 percent in the Palo Verde subarea, and the overall <br />efficiency, including lateral seepage, was 39 percent. <br /> <br />The salt emanating from the Palo Verde subarea derives from the saturated <br />alluvium underlying the subarea, and the unsaturated soils above the water <br />table. The salt in the ground water is apparently being flushed out by <br />irrigation water percolating through the aquifer to the nearest drain and <br />by canal seepage. Flushing occurs to a depth of about 450 feet, the depth <br /> <br />(.':') 2 fJ 3 7 <br /> <br />11 <br />