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Mr. Hal Simpson • • <br />July 25, 1994 <br />Page 3 <br />REPLACEMENT SOURCES <br />Cooley Gravel Company acquired 1.5 shares of the Smith and Emmons <br />Ditch with the property. Historically, and presently, the water <br />was used continuously on the land to irrigate crops. A copy of <br />the ownership certificate for Cooley's 1.5 shares is enclosed. <br />Historic consumptive use from the use of Smith and Emmons water <br />will be used to replace depletions during the irrigation season. <br />For those non-irrigation months which direct flow credit is not <br />available Cooley has leased effluent from the City of Longmont. <br />The following Table 2 shows the total diversions for the Smith <br />and Emmons for the period 1951-1980. As shown the average <br />diversions are 1347 acre feet per year. Cooley's portions of the <br />diversions is 253 acre feet per year. The monthly distribution <br />of Cooley's share of the diversions is shown on Table 3. The <br />irrigation season usually begins in Mid April and ends in late <br />September. We estimate that the ditch loss is 10% and the <br />irrigation efficiency is 55% for an overall irrigation efficiency <br />of 50%. The amount of irrigation water available for crop use is <br />shown on Table 3. The average annual water available is 126 acre <br />feet per year. <br />The potential consumptive use was determined using the modified <br />Blaney-Griddle method. Weather data was obtained from the <br />Longmont station. The period of 1951-1980 was chosen to <br />calculate historic use. The results of that analysis are shown <br />on Table 3. The potential consumptive use, including effective <br />precipitation averages 25.72 inches per year. In order to <br />determine the amount of effective precipitation to be used as a <br />credit against evaporation the effective precipitation was <br />separated from the irrigation consumption. Table 3 shows that <br />the potential consumption of irrigation water is 19.6 inches or <br />312.77 acre feet. <br />The historically irrigated area was determined by air photo <br />(enclosed)•and field evidence. Based on this information 185 <br />acres have been irrigated. The consumptive use by the crops was <br />determined by taking the lesser of the potential consumptive use <br />and the amount of water available to the crop. The resulting <br />