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valley plus some canals on the west side for a net lining length of 335 miles of the 552 miles 1n the project. At that time, the net cost- effectiveness of the plan was $368,000 per mg/L, the total con- struction cost was $106 million, and the salt reduction at Imperial Dam was 19.8 mg/L. Analysis IV was displayed and explained at the environ- mental scoping meeting. No significant negative responses were voiced regarding this plan. The 335 miles of canal and lateral lining were gradually reduced by 5 miles as feasibility-level information was developed between March and September 1980. New data included piezometer tests, additional well monitoring, and intensive analysis of the water-salt transfer mechanisms. Based on the new data, a feasibility-level cost estimate for the recoDDDended plan developed with the public was determined to be $178 million (October 1980 prices). The costs and impacts of lining the remainder of the canals and laterals on the west side were not quantified as they were considered to be a relatively poor salinity control invest- ment based upon earlier analyses. The net result of these computations yielded a cost-effectiveness figure for the recoDDDended plan that was developed with the public of $1,100,000 per mg/L, using a 7-3/8 percent, 50-year amortization criterion. Based on this analysis, a new plan was formulated wherein canal and lateral lining for the west side of the valley was deleted. Based on this approach, Water and Power's recoDDDended plan is described below. Water and Power's RecoDDDended Plan A total of about 254 miles would be concrete lined under the recom- mended plan. Where field conditions warrant, flexible lining w~idldiaO 19