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<br />maintained in a location that was conducive to accurate readings, and was representative <br />of the surrounding areas. An average of the ET readings for the two weather stations was <br />used as the final reading for the analysis. <br />Appendix D: Evapotranspiration Table <br /> <br />After obtaining all of the ET data from the sources previously mentioned, the data had to <br />be extracted and converted into an Excel. At a minimum, all of the weather stations <br />provided ET data for alfalfa, a commonly used reference crop. However, a few of the <br />weather stations also provided ET information for Bluegrass, the crop that would be <br />utilized for the analysis. For the weather stations that only provided alfalfa data, the <br />annual ET for the Bluegrass growing season (May-Sept) was extrapolated by using the <br />average percentage difference between alfalfa and bluegrass that was obtained from the <br />weather stations that had data for both crops. To cross-checl< the results, the annual ET <br />for Bluegrass was calculated using the crop co-efficient from alfalfa. Effective <br />precipitation (the amount of precipitation assumed to have penetrated into the soil and <br />made available for plant use) was subtracted to get the final ET calculation. According to <br />a Water Conservation Specialist at NCWCD, effective precipitation accounts for about <br />50% of all precipitation. <br /> <br />Landscape Size: Very little processing of the measured landscape size was required. In <br />the water records results template previously mentioned, landscape size was entered in a <br />single cell and then a simple conversion from feet squared to acre/inches was performed. <br />To calculate how many inches of water a household was using outdoors, square footage <br />was converted to acres. Next, the total number of outdoor gallons used was converted to <br />acre-inches. The acre inches were then multiplied by the total property acreage to <br />determine how many inches of water were used outdoors in any given year. <br /> <br />(total outdoor gallons / acres) * (1 acre inch / 27,154 gallons) == inches <br /> <br />22 <br />