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Table 4. Proposed Method for Evaporation Calculations <br /> Example: Average Monthly <br /> Evaporation for 2.5 acre <br /> Month Days/Month Average Daily ETo' Open Water ET.Coefficient2 pond3 <br /> inches pond depth<6.5 feet acre-feet <br /> January 31 0.000 1.05 0.000 <br /> February 28 0.000 1.05 0.000 <br /> March 31 0.093 1.05 0.628 <br /> April 30 0.142 1.05 0.934 <br /> May 31 0.173 1.05 1.173 <br /> June 30 0.213 1.05 1.398 <br /> July 31 0.218 1.05 1.475 <br /> August 31 0.185 1.05 1.253 <br /> September 30 0.144 1.05 0.945 <br /> October 31 0.080 1.05 0.540 <br /> November 30 0.000 1.05 0.000 <br /> December 31 0.000 1.05 0.000 <br /> Total(acre-feet) 8.35 <br /> Total(inches) 40.08 <br /> (1)Reference ET for grass calculated by NCWCD using ASCE Standardized ET Equation(www.ncwcd.org).For Greeley West Weather Station. <br /> (2)Open water coefficient obtained from FAO 56-Crop Evapotranspiration(http://www.fao.org/docrep/x0490e/x0490e00.htm#Contents) <br /> (3)To calulate monthly evaporation:Days/month*Average Daily ET,*Open Water ET,Coefficient surface area of pond <br /> S;= initial storage in ponds (at beginning of time interval) <br /> ET= evaporation and evapotranspiration losses <br /> Sf=final storage in ponds (at end of time interval) <br /> Calculation of Net Recharge from Canal Reach Segments <br /> When water is diverted from the river for recharge, the portion of water that is not <br /> delivered to recharge ponds (assuming there is no outflow through the tailend of the <br /> canal or that it is measured and accounted for) is lost through seepage from the canal to <br /> the aquifer. Seepage that occurs during this process can legitimately be claimed as <br /> recharge. Canal segments were identified in this study for this purpose. <br /> The following equation should be used to determine the total net recharge that occurs <br /> via the canal. <br /> R = 1— ET- 0 <br /> Where, <br /> R= net recharge <br /> /= inflow <br /> ET= evaporation and evapotranspiration losses <br /> 0 = outflow from the ditch (deliveries to recharge ponds) <br /> Aqua Engineering, Inc. Recharge Project Potential <br /> February 17, 2004 - 13- <br />