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Show 124 Problems of imperial, valley and vicinity. Elkhead Creek.-Pick-up canals from both sides of the watershed tributary to Park reservoir site on Elkhead Creek are proposed. The run-off from this creek is 57,000 acre-feet, and 40,000 is needed for the 23,000-acre project directly adjacent to the creek, leaving a surplus of 17,000 acre-feet, of which possibly 15,000 can be diverted. OTHER MIXOR SUPPLIES. On the project itself are small creeks which may yield 12,000 acre-feet after supplying present rights. Summary of water supply. Acre-feet. Elk River (Trans-Mt.).................................;................ 110,000 Little Snake........................................:................... 70,000 Slater Creek............................................................ 40,000 Elkhead Creek (Trans-Mt.).............................................. 15,000 Minor creeks............................................................ 12,000 247,000 Return flow possibly 50,000; because of proximity to land its efficiency should be doubled", giving......,....................................... 100,000 347, 000 140,000 acres, at 2.5 acre-feet............................................. 350,0D0 Conclusions.-Data on both the irrigable land and the water supply are very meager. While stations have been maintained at base points on all the streams, yet the yield which may be expected from intercepting canals at higher elevations is problematical. From what data are available from the estimates made, the supply of water is too small to cover all the irrigable land, and more complete knowledge may show that the acreage assumed should have been smaller. Reservoirs.-While the total amount of water is assumed sufficient for 140,000 acres, the amount of reservoir capacity necessary to control it can be only roughly estimated. Assuming 50,000 acre-feet of return flow available for diversion during irrigation season and assuming, further, that it will be twice as efficient as natural flow because it can be used immediately without losses from long canals, the reservoir capacity required for an average year is 100,000 acre-feet. (See following table.) Total estimated supply (acre-feet). Elk River. Little Snake. Slater Creels* Elkhead Creek. Miscellaneous creeks. Total. Return flow. Total. September........... October... 5,000 6,000 2,000 2,000 2,000 1,000 1,000 8,000 9,000 2,000 2,000 • 2,000 8,000 9,000 2,000 2,000 2,000 2,000 3,000 23,000 104,000 104,000 49,000 39,000 November........ December.. 2,000 2,000 2,000 January... February........ 2,000 March. . u.. 2,000 7,000 33,000 16,000 1,000 4,000 16,000 17,000 3,000 23,000 84,000 83,000 22,000 7,000. 20,000 21,000 27,000 32,000 April......... 7,000 8,000 5,000 7,000 May............. 20,000 50,000 22,000 7,000 June.. July...... August............. Total.......... 110,000 70,000 40,000 15,000 12,000 247,000 •100,000 347,000 |