AZ vs. CA:11 California Exhibits, Vol. XI; Nos. 1001-1011; 1101-1109; 1201-1251; 1301-13431301-1343

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CALIFORNIA DEFENDANTS Exhibit No. 1205 Identification: July 12, 1957 Admitted: Extract From Twentieth Biennial Report of the State Engineer to the Governor of Colorado for the Years 1919-1920. (p. 29) Of a possible 2,000,000 acres that Colorado may ultimately irrigate from tributaries of the Colorado River, only 750,000 acres are now irrigated. In comparison with this area the annual runoff or stream-flow of Western Colorado which passes now unused across the State line is 10,000,000 acre-feet. The total net demands or consumptive use of water for 2,000,000 acres will approximate, and probably not exceed, over 3,000,00 acre-feet, since ultimately large volumes of water used for irrigation return to the streams as seepage or return water. Irrigation investigations show that generally from 20 to 40 per cent of the water applied to land for irrigation ultimately returns to the stream channel. This is well illustrated in the irrigation history of the North and South Platte Rivers. The annual measured return flow of the South Platte River in Colorado between La Salle and Julesburg, a distance of 150 miles, now amounts to 800,000 acre-feet annually. Records of return flow secured in 1900 for the same river section show the gain at that time to have only been 350,000 acre-feet. On the North Platte River between Whalen, Wyoming, and North