AZ vs. CA:24 California Exhibits, Vol. XXIV; Miscellaneous

page 182

182 PEOBLEMS OF IMPERIAL VALLEY AND VICINITY. COLORADO RIVER. From junction Green-Grand to San Juan. [Assumed control by reservoir at junction.] Present average annual discharge............................acre-feet.. 12,260,000 Estimated ultimate after irrigation development above............do___ 9,480; 000 Equated discharge: Present..............................................second-feet.. 17,000 Ultimate...................................................do___ 13,000 Elevation at junction............................................feet.. 3,875 Elevation at San Juan, about.................................. .do___ 3,475 Total fall.................................................do.... 400 Distance.......................................................miles.. 200 Potential horsepower: Present.......................................................___ 680,000 Ultimate......................................................... 520,000 From San Juan mouth to high water proposed Boulder Canyon reservoir. Present discharge at mouth of San Juan......................acre-feet.. 14, 960,000 Present discharge at Boulder Canyon.........................___do___15,700,000 Average for section........................................do___15,400,000 Estimated ultimate after irrigation above........................do___ 11, 200,000 Equated flow: Present..............................................second-feet.. 21,000 Ultimate...................................................do___ 15,500 Elevation at mouth of San Juan...................................feet.. 3,475 Elevation water surface Boulder Canyon reservoir................do___ 1,275 Total fall.................................................do___ 2,200 Distance......................................................miles.. 325 Potential horsepower: Present........................................................... 4,620,000 Ultimate......................................................... 3,410,000 Because of necessity for preserving the Grand Canyon National Park from industrial invasion, probably only half the potential power in this section is actually realizable. From Boulder Canyon to mouth of Colorado.-At Boulder Canyon the Colorado River begins to emerge from the deep canyons which have confined it up to that point. Dam sites are not frequent below Boulder Canyon nor can high dams be built because of shallow canyons. The river grade is flat and irrigable lands and towns might be submerged by reservoirs. Assuming a part of the head at Boulder Canyon to be used for regulation, there are three power sites as follows: Boulder Canyon.............................................................320 Bulls Head..................,............................................... 155 Williams Fork............................................................... 75 Total.................................................................550