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. WATER REQUIREMENTS Agricultural Water Requirements There are about 32 ditch systems in the Cache la Poudre River Basin serving approximately 240,000 acres of land, based upon an irrigated acreage survey made for the Colorado-Big Thompson Project. As previously indicated, the area receives surface water from the Cache la Poudre River via direct diversions, from releases of storage water from ditch company-owned reservoirs located on the plains and in the mountains of the basin, from transbasin importations, and from the Colorado Big-Thompson Project, Because of the uncertainty of the need for additional supplemental water for this irrigated area, detailed studies of supplies, require- ments, and shortages were not made for each ditch in the basin. However, an agricultural water utilization study was made of the area in its entirety. This study consisted of a monthly comparison of supply witu requirement for the period of study, . The irrigation requirements for this study were estimated by a method in which the assumption is made that total water use in an individual year of adequate supply is a measure of requirement. Through inspection of total agricultural water use, the irrigated area was judged to have a full supply during the year 1958. Hence, the water supply used in 1958 is a measure of the total water requirement in that year. For determining the irrigation requirement for other years, the 1958 requirement was used as a base, and adjustments were made to reflect annual variance in weather conditions, These adjustments were based on theoretical consumptive use requirements and effective precipitation. The annual irrigation supply used in the study included supplies obtained from transbasin importations and the Cache la Poudre Basin surface sources, Colorado-Big Thompson deliveries adjusted to reflect full operation during the study period, and ground-water pumping adjusted to reflect the 1961 level of development, The results of this study are summarized in table 6. . As indicated in table 6, shortages being experienced by agricultural interests in the Cache la Poudre River Basin amount to slightly less than 5 percent of the farm headgate requirement, Conversely, they are receiving approximately 95 percent of their total requirement. It is believed that the small remaining farm irrigation shortages could be Virtually eliminated by further improve- ments in water management practices, The North Poudre Irrigation District, for example, has applied for a Small Reclamation Project Loan to provide funds for the construction of a reregulatory reser- voir. This reservoir could essentially eliminate the shortages in this system by permitting more efficient use of the supply now available, 18