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Show PROBLEMS OF IMPERIAL VALLEY AND VICINITY. 39 Table No. 12.-Estimated ultimate demand-Continued. ACRE FEET. Above Laguna Dam. Below Laguna Dam. Gravity. Pumping. Total (round figures) Acres..................................... Demand (acre-feet per acre).............. January.................................. February................................ March.................................... April..................................... M*y...................................... June..................................... July..................................... August................................... September.......................%....... October.................................'. November............................... December................................ ToUl.............................. 305,000 «3.00 1,532,000 4.40 183,000 3.50 30,000 30,000 107,000 107,000 108,000 138,000 138,000 108,000 90,000 45,000 30,000 16,000 182,000 337,000 612,000 674,000 797,000 920,000 920,000 766,000 644,000 460,000 276,000 152,000 18,000 32,000 58,000 64,000 75,000 86,000 86,000 73,000 65,000 44,000 26,000 15,000 915,000 6,740,000 641,000 2,020,000 iio 230,000 400,000 780,090 850,000 1,140,000 1,140,000 950,000 800,000 650,000 330,000 150,000 8,300,000 'Net. Although all of the foregoing estimates and assumptions rest on many uncertainties, the general conclusion may be drawn in the light of present knowledge that the water supply of the Colorado is equal to all the demands which will be made on it. STORAGE REQUIRED. Should the upper basin and power in the canyon region develop as has been outlined, consideration of the matter leads to the conclusion that storage will be needed only of sufficient amount to regulate the river for irrigation after it has passed through the large regulating reservoir which may be possible at Lees Ferry just below the San Juan, and also to regulate the 1,330,000 acre-feet of inflow below the reservoir. It is, however, apparent, as was stated previously, that a reservoir primarily for irrigation will be needed at Boulder Canyon, otherwise there will arise a continued series of troubles from conflicts between the lower basin and the power developments or between the lower basin and upper basin irrigationists. It is necessary to adopt a working hypothesis for a basis in considering what is necessary to be done witn the river. Accordingly, the problem has been worked out for three plans. (1) To provide storage which will be necessary when the most feasible irrigation developments in both the upper and lower basins have been made. This is the minimum storage which should be provided. In the last five years the average increase of irrigated land in the upper basin has been 80,000 acres yearly. This took place under the impetus of war prices, and it is unlikely that it will exceed that average for some time to come. At the same rate the 1,000,000 acres of most likely land would be irrigated in less than 15 years. In the. lower basin tnere are 710,000 acres of land which are known to be feasible at the present time if the necessary works on which they are mutually dependent can be financed. The time for reclamation of these lands may not exceed 15 years at the present |