OCR Text |
Show the water in the soil cannot increase above the salt tolerance of the crops grown. Basically, therefore, irrigation uses of water within the Colorado River Basin or any river basin will consume the water required by the irrigation process but will return to the streams practically the same quantities of dissolved solids which were diverted from them. To some extent the use of water for irrigation purposes will change the relative amounts of the several dissolved constituents. In passing over and through the soil there is a tendency for the water to drop some of its less soluble salts and to pick up some of the more soluble salts in the soil. The extent of such effect, which is called "base exchange" is limited for any single irrigation use. The total effect upon the quality of any given water supply will depend largely upon the extent of its use and re-use for irrigation purposes. TABLE I USES OF WATER IN COLORADO RIVER BASIN Upper Colorado River Basin* Irrigated Arceage Depletion Ac. Ft. Wyoming, Utah, Colorado, New Mexico and Arizona Year 1922 1920-24 Av. Year 1948 1946-50 Av. Present Depletion Including Presently Authorized Projects 1,370,000 2,003,600 1,366,000 2,049,200 1,385,000 1,926,000 1,385,000 1,883,600 Based on 1929-51 Av. 2,421,000 Based on 1931-47 Av. 2,404,000 Initial Phase-Colo. River Storage Project Based on 1929-51 Av. 3,706,200 Based on 1931-47 Av. 3,671,200 Ultimate Project 7,500,000 * House Document 364-83rd Congress, 2nd Session Lower Colorado River Basin* Gila River Colorado River Depletion Depletion Acreage Ac. Ft. Acreage Ac. Ft. Year 1922 Arizona 344,318 72,893 New Mexico 8,933 4,217 Utah 18,148 Nevada 10,094 California In-Basin 40,839 Out-of-Basin 340,000 Mexico 4,001 Not Known -25- |
Source |
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] : |