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The storage units included in Phase II also would have associated pumping plants, powerplants, and tunnels. In addition, it is anticipated that the southern California area will require an increasing amount of regulatory storage. This storage has been included in the plan in anticipation of this need and would be constructed in increments at locations to be determined from future operating experience, but tentatively assumed to be at the Apple Valley and De Luz sites. The Southern Nevada Water Supply Project is proposed to be built in stages with additional incremental capacity added as the demand grows. Phase II of the Pacific Southwest Water Plan includes provisions for adding a second and third stage to the project. Alternative Plans--In developing the proposed Pacific Southwest Water Plan several alternatives were considered for many of the facilities included. The principal alternatives are discussed in this section. Under more detailed investigation, particularly of Phase II facilities, it is possible that some modification may prove desirable, either through use of some of the alternatives discussed or other methods of obtaining the needed accomplishments. For Arizona, incremental aqueduct capacity could be staged as assumed in the proposed plan, or built during the initial construction. The enlargement during initial construction could provide a means to deliver Arizona's adjudicated water and additional water available in the river during early years of project operation before Upper Colorado River Basin depletions reduce the flow. This initial incremental capacity would cost about $190,000,000 more than the basic Central Arizona Project Aqueduct. Initially it could double the quantity of water diverted to central Arizona and would also initially overcome the ground-water overdraft. The enlarged aqueduct was not used in the adopted plan herein presented because a permanent water supply would not be available until completion of Phase II construction. Another alternative to the proposed incremental aqueduct capacity would be to divert from a desalting plant output point at Imperial Dam. This alternative would make higher-quality water available to all areas diverting from Imperial Dam. The alternate aqueduct plan from Imperial Dam to Phoenix and Tucson metropolitan areas would cost about $400,000,000. The cost of power for project purposes has been based on assumptions varying with the use location. Baseload pumping to Arizona is supplied by hydroelectric production. Baseload pumping on the California Aqueduct is assumed to be supplied by privately financed fossil fuel fired thermo-electric plants, as have the power and heat requirements for the pilot desalting plant or the alternative desalting system subsequently discussed. Alternative to this supplying of power would be the use of publicly financed thermo-electric power for VI-7Epson Perfection 4870 Photo, 400 dpi, 8 bit, 14,137,344 byte