AZ vs. CA:08 California Exhibits, Vol. VIII; Nos. 371-398F

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0SK OF WATERS OK LOWKR COLORADO RIVER FOR IRRIGATION. 8 in the various documents referred to and in the first, second, and third annual reports of the reclamation service. The present report is intended to give in the briefest form possible the more important facts and the genoral conclusions of the studies of Colorado River carried on through many years by various individuals. VARIOUS QUESTIONS INVOLVED. The resolution directs that the report shall cover the various questions involved in connection with tiie use of the waters of the lower Colorado River for the irrigation of arid lands in the State of California, the Territory of Arizona, etc. These questions naturally fall into two groups, viz, physical and legal. The physical questions, namely, those of topograpfiy and water supply, have been the subject, as above stated, of long and careful study. Tim legal questions have been given general consideration such as is necessary from the standpoint of the engineer or business man, but these matters are recognized as pertaining more properly to the cognizance of the legal officers of the Department. PHYSICAL CONDITIONS. The Colorado River is one of the largest and most important streams of the arid regions. It has its principal sources in Wyoming, Colorado, New Mexico, and Utah, and flows through the Territory of Arizona, forming a portion of the boundary between Arizona* and the States of Nevada and California. It then becomes part of the international boundary between the United States and Mexico, and finally crosses a portion of the latter Republic, discharging into the Gulf of Mexico. The waters of this drainage system are utilized for irrigation of lands in the five States and two Territories named and in the Republic of Mexico. Upon the utilization of its waters is dependent the prosperity of agricultural communities which have been established and are annually expanding in various localities in these political divisions. The river in its flow varies widely from the high floods of the early spring to the extreme low water of late summer. The discharge during flood months has averaged about 53,000 cubic feet per second and during low-water months 2,500 cubic feet per second. For nine months or each year the flow has usually been below 10,000 cubic feet per second. The average annual discharge has been about 8,000,000 acre-feet. In its unregulated condition there is not enough water flowing in the stream during the irrigation season to supply the future demands of the fertile but arid agricultural lands along its course. The stream, to reach its full value to the country, must, in the future, be regulated by storage works, so that the large amount of water dischargedby the stream will ho available at the times when it can be used for irrigation, such storage works being placed at suitable points on the headwaters for the benefit of lands farther downstream. The river in its natural condition is navigable in its lower course during a considerable part of the year. The navigation is relatively small, and, in the opinion of the army engineers, it is not advisable to attempt improvements of the channel; nevertheless, the navigation of