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Show PROBLEMS OF IMPERIAL. VAULJ3Y AND VICINITY. 159 Diversion duties will vary from 3.5 acre-feet in the lower altitudes to 1.5 acre-feet, or less, in the higher altitudes, the difference being due largely to variation in precipitation. Consumptive use will vary from 2 feet to 1 foot or less. Power development.-There is one power development in the San Juan Basin at present. This is the Tacomaplant, located on Anima~ River, between Durango and Silverton. Water is supplied by Cascade and Elbert creeks through a 21,000 acre-foot reservoir. The plant has a 988-foot head. The installation of two units has a rated capacity of 4,500 kilowatts. The output is used for mining, milling, and lighting. Opportunities for further power development by means of high head plants similar to the one constructed are probably existent thougn definite data are lacking. Developments on the main streams require storage since the winter flow is too small to warrant construction of power plants. Lack of storable water and present irrigation requirements further limit power possibilities to the Animas and San Juan rivers. The Animas has an average flow of 719,000 acre-feet annually, of which but 80,000 acre-feet are now in use with the possibility of further use of possibly 309,000 acre-feet, which would require the construction of Animas reservoir, leaving 330,000 acre-feet unused with ultimate irrigation development from this stream. Its capacity is sufficient to control the river and the irrigation release could be used for power purposes, the amount so used depending upon the elevation of the outlets-for irrigation and the amount of water released for use below. In case of consolidation of the La Plata Meadows and Overland projects with a common outlet at considerable height above stream Ded, the mean power output would be that derived from the release of approximately 600,000 acre-feet at a mean head of 100 feet, equivalent to" a uniform power output of 7,000 horsepower. ' * On the San Juan River, power possibilities exist at the Hogbapk and Bluff sites, but since the iormer would entail considerable destruction of present irrigated area without offering any more advantages than the Bluff site, only the possibilities at Bluff will bev outlined^ At the Bluff site, the anticipated run-off when all outlined projects become developed will be 1,650,000 acre-feet annually wnich, if equated, will permit a power output of 35,000 horsepower with a mean head of 175 feet, wnich would allow 740,000 acre-feet of equalizing storage and 840,000 acre-feet of dead storage if the water surface is raised 225 feet. At the present time, silt carried past the dam site is estimated to be 29,000 acre-feet annually, which would give so shott a life to the reservoir that it is hardly worth while developing when the irregular flow of the San Juan is. considered. If irrigation should go ahead as estimated in the following pages;; it would equalize the flow and decrease the annual silt to some extent so that this may become a feasible power site. It is not considered in estimates of. power, however. The Bluff site has also been considered fefr tegulakion of floods for protection of, the lower river,.but its effectin this direction would not be large. > • J. Future development will Drobably Job Along the lilie of high head plants in the headwaters region ana will be"limited by local markets, for power as present consuming centers are far removed with better power sites closer at hand. ' - ¦- ¦: ;:^-« »-, ':s •••¦'•-•- |
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Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : |