OCR Text |
Show Totals In-Basin 357,252 1,029,100 146,191 501,500 Out-of-Basin-1922 340,000 2,186,600 Out-of-Basin 1920-24 Av: 2,404,000 Year 1948 Arizona 716,1H 113,416 New Mexico 11,728 4,332 Utah 22,100 Nevada 11,321 California In-Basin 63,676 Out-of-Basin 427,850 Mexico 3,962 Not Known Totals In-Basin 731,801 1,810,100 Out-of-Basin-1948 3,183,800** Out-of -Basin-1946-50 3,215,500** * Report on Water Supply of the Lower Colorado River Basin, Project Planning Report, U.S.B.R., November 1952. ** Includes the figure of 180,500 Ac. Ft. of water which was diverted to Metropolitan Water District in 1948, This diversion has increased substantially since 1948. Domestic, municipal and industrial uses, although vital to development of the basin, will constitute a relatively small percentage of water consumption. Their relative effect on the quality of water will, be much the same as that of irrigation. In the report it is assumed that use of water for these purposes will neither add nor subtract from the total quantities of dissolved solids carried by the streams. Some basins where irrigation is now or may be practiced contain soils or ground waters or both which carry greater than usual quantities of soluble salts. In such areas, irrigation can be successfully practiced only by leaching away the excess salts. If the subsoil is porous, leaching may occur as a part of the irrigation process; if not, it may be necessary to install drainage conduits to carry away the excess salts and water. Even in basins where the salt content of the soil is normal, the process of irrigation will naturally leach some chemicals from the soil and leave some which were carried to the land by the irrigation waters. In each new irrigation project there will usually be some temporary increase in salt content of the return waters due to a flushing out of the irrigated lands. An analysis of the arable lands of the Upper Basin which are being considered for irrigation development under the proposed Colorado River Project indicates that areas where the soil concentrations are greater than ordinary constitute but small fractions of the total. The important facts in any area where leaching of the soil may occur are: (1) that the resulting salt increase is usually -26- |
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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] : |