AZ vs. CA:24 California Exhibits, Vol. XXIV; Miscellaneous

page 165

PROBLEMS OF IMPERIAL VALLEY AND VICINITY. Water supply and irrigation requirements. [Acre-feet.] 165 Month. Supply. Irrigable demand. Demand on storage. April...... .May....... June___ July....... August___ September. Total 12,000 33,000 19,000 8,000 5,000 3,600 6,400 16,000 24,000 16,000 12,000 5,600 5,000 8,oeo 7,000 2,000 80,600 80,000 22,000 Of the above 22,000 acre-feet of storage required, 5,000 are to be provided in Hermosa Creek, leaving 17,000 to be found in La Plata drainage area. This storage is said tp.be available. Conclusion.-The water supply for this project is apparently sufficient only for its bare needs and can not be considered ample. It can, however, be improved by the enlargement of the diversion canal from the Animas watershed or by the provision of additional storage in this watershed. '...-' The construction cost will undoubtedly be high and deter construction for some time. OVERLAND PROJECT. Irrigable area, 83,000 acres. Mean annual temperature, 50°. Mean annual precipitation, 6 to 8 inches. Precipitation during growing season, about 3 to 4 inches. Elevation, 5,500 to 6,300 feet. Interval between killing frosts (summer), 140 days. Transportation, Denver &' Rio Grande Railroad, Farmington branch (standard gage connecting with narrow gage at Durango), 3 to 25 miles away. Irrigation plan.-Water is to be diverted from the Animas River near the State line by a gravity canal system. The main canal, with a length of about 100 miles, will cover most of the irrigable land in townships 12, 13, 14, and 15 of ranges 30 and 31 north. The main canal will run through much difficult country, and the lateral systems due to heavy southward slope of the country and deeply cut drainage systems will also be expensive. Duty of water.-Diversions for this project, owing to the length of the canal system, are expected to reach 3 acre-feet per acre, with a consumptive use of 2 acre-feet, rainfall being so light as to help but little in the production of crops. Water supply.-All water will be derived from the Animas with 10,000 acres now being irrigated and with anticipated diversions of 60,000 acre-feet annually for the La Plata Mesas project. The mean annual discharge of the Animas at Durango has been 719,000 acre-feet, of which 639,000 acre-feet would be available for this project. With diversions of 249,000 acre-feet, there would still be a big surplus. Relation of water supply to demand in a moderately low year like 1918 would have been as follows: