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and water delivery schedule modifications. Brief descriptions of these measures and the <br />development of associated implementation unit costs are provided below. <br />Canal Lining <br />This measure would reduce seepage losses from the Districts' delivery systems by placement <br />of lining material within selected canal sections. Development of seepage loss and <br />implementation cost estimates presented are based primarily on information from several <br />documents including Central Nebraska Public Power and Irrigation District's (CNPPID) <br />Irrigation Division Water Conservation and Management Program (Program), the Central <br />Nebraska Regional Water Conservation Task Force 1994 Comprehensive Water Conservation <br />Plan (Plan) and the 1996 Supplement to the Plan, and Reclamation's Deschutes - Canal Lining <br />Demonstration Project Construction Report. <br />In the development of the lining unit cost estimate used, it is assumed only selected high loss <br />portions of the system would be lined. Specifically, it is assumed that less than 20 percent of <br />the systems that have capacities of 150 cubic feet per second (cfs) or greater would be lined <br />and that associated losses would be significantly higher than the system average. Evaluation <br />of delivery system records presented in Figures 4 -1 and 4 -2 of the Program indicate an annual <br />average canal loss seepage rate of approximately 1,000 acre -foot (af) per mile. Based on <br />documented seepage loss rates associated with Reclamation projects, and seepage loss <br />estimates included in the 1996 Supplement to the Plan, annual seepage rates for medium to <br />large canals (150 -500 cubic feet per second) typically range from 1,000 to 4,000 of per mile. <br />Based on this information, an assumed annual seepage loss rate of 2,000 of per mile is used. <br />Canal lining installation costs used in this evaluation are based on information included in the <br />Plan's Appendix E (page 80). The unit cost per mile of lining used ($459,400) represents a <br />composite of 60% medium and 40% large full -prism canal lining costs as provided in the Plan. <br />This estimate compares well with actual installation costs on Reclamation projects, and with <br />installation costs reported in the 1996 Supplement to the Plan. It is assumed lining installation <br />would have a design life of 40 years and that there would be no additional operation and <br />maintenance associated with the lined canals. <br />Groundwater Supply Development <br />This measure would include the installation of several shallow wells located strategically <br />throughout the delivery system. They would be operated to supplement irrigation deliveries <br />while modifying the artificial groundwater mound which exists throughout most of the <br />Districts' delivery areas. <br />Well installation, replacement, and operation and maintenance costs used in this evaluation are <br />based on the following assumptions. It is assumed a typical well field would pump an annual <br />quantity of 7,200 of against a total dynamic hydraulic head of 70 feet. This converts to 30 cfs <br />of continuous pumping for 120 days. It is assumed each well field would have a 15 year <br />design life and the salvage value at the end of the 40 year period is neglected. Based on these <br />assumptions, the estimated installation and replacement cost for each well field would be <br />F, <br />n <br />0 <br />