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ctl ~ m C:J filling. During the spring snowmelt there is plenty of water for most senior rights. By late summer, when natural flows have subsided and irrigation demand is high, ~he Cameo diversions will place a call on the .river, preventing most upstream reservoirs from continuing to fill. Releases from Green Mountain Reservoir are irtCreased during this period to mitigate the effe~ts of the, water right call. 2. Project Area The project area is comprised of nine major drainage basins: West Divide Creek, Alkali Creek, East Divide Creek, Hamm Creek, Dry Hollow Creek, Yank Creek, Thomps.on Creek, Owens Creek, and Buzzard Creek. The total amount of presently irrigated areas is about 14,900 acres and the total number of potential irrigated acres is, about 19,600 in all these basins combined. The average annual diversion requirement for the project area crops is 3.12 feet per acre'. On the average, sixty,-four percent of the total amount diverted for irrigation is lost to the atmosphere through crop evapotranspiration. Thus the average annual consumptive use is 2.0 ac-ft per acre. The remaining 1.12 feet represents system losses such as canal seepage, and direct runoff from irrigation (return flows), which may eventually appear elsewhere i~ the basins for possible reuse. Because no water storage or reservoirs currently exists within any of these basins, the present pattern 'of irrigation involves flooding the irrigated areas with as much water as possible in Mal' and June. By early July the normal stream flow drops to levels which preclude or markedly reduces further irrigation. Irrigated crops must survive the' remainder of the growing season on residual soil moisture and available precipitation. The average annual amount of, water available in the project area is 88,300 acre-feet. The total amount required for diversion to .existing irrigated area averages 46,500 acre-feet per year, and the average annual existing shortage is 23,900 acre-feet. There are about 9,150 acres of land in the existing We.st Divide Creek irrigation system which are presently irrigated from four major irrigation ditches. These ditches are supplied by West Divide Creek, Dry Hollow Creek and Alkali Creek, The average annual diver- sion requirement for irrigated lands is 28,550 acre-feet. The average annual flow in the West Divide Creek system is almost 30,800 ,acre-feet or 2,250 acre-feet more than the average annual diversion requirement. Irrigation water shortages exist because the distribution of annual flows does not coincide with, the distribution of annual demand. 1-3