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Two alternative plans were identified. The first plan, Alternative 1, minimizes structural works. The second plan, Alternative 2, maximizes irrigation efficiency and salt load reduction. This latter plan is desig- nated the "Environmental Quality Plan" and provides the greatest reduction in salt loading. Net economic benefits are largely derived from reduced salinity. This results in the "Environmental Quality Plan" yielding the highest net benefits; therefore, Alternative 2 is also identified as the "Economic Development Plan." All alternatives are evaluated for a 25-year project life at seven and three-eighths percent interest after a ten-year installation period. The ongoing conservation program is assumed to con- tinue for all alternative conditions. Fo110wup technical assistance is necessary to maintain present irrigation efficiency with future conditions. The major practice in both alternative plans is onfarm irrigation water management. The off-farm conveyance system improvement alternatives were identified by the SCS and the Clark Conservation District in August 1978 and are used in this study. The alternatives consider fish and wildlife resources. Assessment of fish, wildlife and recreation, etc. are located in the Environmental Evaluat- ion Appendices. The impact on the visual resource and its quality was con- sidered. The proposed alternatives will not advers1y impact these resources. Other nonreturn flow and concentrated return flow uses of water from irrigated lands were examined. Water not used for irrigation may be allocated for industrial use or power generation purposes. Saline waters from return flows could be used to develop additional wildlife habitat. Return flow ditches presently provide some wildlife habitat. Flow in these ditches will be reduced and result in minimal habitat disturbance. The proposed onfarm measures would not result in land modification below plow depth and therefore, will not effect cultural resources beyond present agr. .u1tura1 activity. Future Without Salinity Program The future without program for salinity control condition is based on projected changes without implementation of a salinity control program. Proj";;ted land use change from agricultural to urban is 425 acres. Some 85 acres are estimated for building lots and the remainder for use as small pastures, lawns and gardens. Irrigated land considered for this alternative is 4,897 acres distributed as fo 11 ows: 48% alfa1 fa 25% pas ture 20% barley 7% sudan grass No change in production levels are considered. Changes in onfarm irri- gation systems would result from ongoing conservation programs. 37 OOZ717