OCR Text |
Show tive uses above Lees Ferry would increase to about 3,200,000 acre feet annually. Ultimately it is assumed that the full consumptive uses contemplated by the compact will be attained in each basin (see Table I). The compact states in Article VIII that "present perfected rights . . . are unimpaired by this compact." The word "impair" has been seized upon by certain Lower Basin interests as a basis for their contention that the Upper Basin is obligated to deliver a certain quality as well as a certain quantity of water at Lees Ferry. Whether the wording of the compact itself or the water law of the western states imposes any obligation on the part of the upstream user to deliver water of a given quality to a downstream user, or whether it does not, the question of quality has been raised by opponents of the legislation and should be answered as fairly and accurately as possible. This report will attempt to show in some detail the effect of the Initial Phase of the Colorado River Storage Project and Participating Projects on the quality of Colorado River water at Lees Ferry. It will also show, in a general way, the quality of water which can be expected after full development of the Upper Basin as contemplated by the 1922 compact. Factors Affecting Quality of Water There are a number of factors which affect the quality of the water which falls in any stream basin. Precipitated as nearly pure water in the form of rain or snow it immediately starts to gather soluble materials from the soil over which or through which it passes. Man, in using water for his purposes, may change the quality of water in a river basin to a considerable extent. Some of these man-produced factors are irrigation; domestic, municipal and industrial uses; drainage, including the leaching of salts which may have accumulated in the soil; storage of water in major hold-over reservoirs; and the diversion of water outside of the natural drainage basin. Up to the present time, at least, man's activities have had little or no effect upon the natural processes of precipitation, runoff or percolation to the natural streams. Whether, in the future, he may be able to produce an appreciable change in these factors seems questionable. It is assumed in this report that the natural accumulation of dissolved solids in the waters of the Colorado River Basin will not be changed by man's activities. The consumptive use of water by irrigation is probably the major man-produced factor which affects the quality of the waters of western streams. In the irrigation process, water is diverted from a stream (or pumped from underground) and spread upon the land. A substantial portion of this water is taken up by the growing crops, the remainder either flowing back to natural channels as waste water, percolating into the ground and finding its way back to natural channels, or being evaporated into the air. Very little of the dissolved solids in the water is absorbed by the plants. The salts carried to the land, therefore, must either be carried back to the streams in the return waters or be deposited on the land. If permanent agriculture is to continue in any basin the salinity of -24- |
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] : |