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<br />-9- <br /> <br />For the purpose of this report a few comrarative assumptions should be <br />sufficient to indicate the relative importance of possible increased willow <br />growth as a result of increased diversions. B,y using the Blaney method and <br />his coefficient for dense native vegetation, which is applicable to willows, <br />together with the temperature and precipitation data for the Walden station, <br />the stream depletion by willow areas may be calculated to be 1.27 acre feet <br />per acre, over the average irrigation period, under full water supply conditions. <br />If, it is a.ssumed the entire 600 acres of questionable willows are presently <br />receiving a water supply sufficient to cause only 50 per cent of such depletion, <br />and that they would have a full supply under increased diversion practices, <br />the average increased stream depletion VTould amount to 380 acre feet per year. <br />If it is assumed that the total questionable willo\'1 acreage is presently re- <br />ceiving the same percentage of water supply as ~as indicated by the North Bark <br />comparison for the hay meadows, then the increased depletion due to increased <br />diversions would amount to about 100 acre feet in ~he average year. The amounts <br />arrived at by these assumptions would be decreased proportionately if a portion <br />of the total questionable willOw area is not actually dependent on irrigation <br />water. If it is assumed that the willows are at present obtaining an adequate <br />supply from ground water, then there would be practically no increase in the <br />stream depletion caused by them even though diversions to the meadow lands were <br />increased. <br />Regardless of the amount of increased consumptive use in Colorado which <br />it might be considered would result from unlimited diversions to the meadowlands, <br />there are natural losses in the channel of the Laramie River below the Colorado- <br />Wyoming state line. It should therefore be recognized that the effect of such <br />increased stream depletion would actually become progressively smaller with . <br />distance, at points below the Colorado area. <br />