Laserfiche WebLink
<br />-6- <br /> <br />The problem with respect to the possibility of an increase in meadorrland <br /> <br /> <br />diversions from the Laramie River and tributaries in Colorado~ above the amounts <br /> <br /> <br />which have been diverted during the period from 1942 to date~ is to estimate <br /> <br /> <br />the possible increase in stream depletion which might result from such a change <br /> <br /> <br />in diversion practices. Since there has been no consumptive use study in the <br /> <br /> <br />area, and there are no adequate records of temperature and precipitation in the <br /> <br /> <br />upper Laramie River basin, the matter becomes one of judgment in interpreting <br /> <br /> <br />and applying such data as are available. <br /> <br /> <br />A method of estimating the consumptive use of irrigation water bY various <br /> <br /> <br />crops has been developed by Mr. H. F. Blaney and others of the Soil Conservation <br /> <br /> <br />Service, U. S. Department of Agriculture. This method was adopted by the <br /> <br /> <br />Engineering Advisory Committee of the Upper Colorado River Basin Compact <br /> <br /> <br />Commission for the purpose of estimating stream depletions in that absin. The <br /> <br /> <br />factors considered in the method are temperature, precipitation, per cent of <br /> <br /> <br />daylight hours and dates of application of irrigation water, 'with all these <br /> <br /> <br />factors being used as long time averages. There is a weather bureau station at <br /> <br /> <br />Walden, Colorado, with a farily long record of temperatures and precipitation. <br /> <br /> <br />The station is at about the same elevation as that of the Laramie River valley <br /> <br /> <br />in Colorado. If the averages of the data here recorded are used in the appli- <br /> <br /> <br />cation of the Blaney method, for a period between May 10 and July 3l, which <br /> <br /> <br />covers the average use of irrigation water in the North Park area, it may be <br /> <br /> <br />calculated that the average stream depletion due to the irrigation of grass <br /> <br /> <br />hay will amount to 0.71 acre feet per acre, if adequate diversions are made <br /> <br />to furnish a full water supply to the crop. <br /> <br /> <br />A consumptive use study was carried on during the years 1937, 1938 and <br /> <br /> <br />1939 for an area of about 5,000 acres situated directly below Ualden. In this <br />