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maximum application efficiencies for flood irrigation and sprinkler techniques shown in <br />Table 5. <br />Table 5 <br />Range of Maximum Application Efficiencies per Irrigation Method <br />Irrigation Method On-farm Efficiencies <br />Border, Furrow, and Flood Irrigation 30 - 70 <br />Center Pivot/Lateral S rinklers 70 - 80 <br />This information is consistent with efficiency percents presented by Duane D. Klamm <br />and John S. Brenner in the 1995 Evapotranspiration and Irrigation Efficiency Seminar <br />sponsored by the American Consulting Engineers Council of Colorado and the Colorado <br />Division of Water Resources. They proposed a range of 50 to 60 percent application <br />efficiency for flood irrigation, 60 to 80 percent for border irrigation, 75 percent for <br />furrow irrigation, and 75 to 85 percent for sprinkler irrigation. <br />Recommendations -Maximum Application Efficiencies <br />The StateCU model uses maximum application efficiencies to estimate the amount of <br />irrigation water delivered to the farm that is available to meet crop consumptive use <br />demands. The actual application efficiency is calculated within the model, and may be <br />considerably less than the maximum application efficiency. The total acreage and the <br />acreage of sprinkler irrigated lands under each ditch system, by year, is input to the <br />StateCU model. The maximum application efficiency is determined by weighting the <br />flood irrigated acreage and associated efficiency with the sprinkler irrigated acreage and <br />associated efficiency. <br />Alan Davey of Davis Engineering provided sprinkler extend maps for 14 years (1975 <br />through 1980, 1982 through 1984, 1989, 1991, 1993, 1996 and 1998), prepared for the <br />Rio Grande Water Conservation District. These maps were digitized and linked to ditch <br />service areas using the GIS ditch service area mapping developed by Agro Engineering. <br />This provided the sprinkler-irrigated acreage over time for use in the StateCU historic <br />consumptive use analysis. <br />Notes from a meeting held with Ralph Curtis in March, 1987, during the Rio Grande <br />Water Supply Study, Phase I, performed by LRCWE in 1990, indicated that at that time, <br />the conservancy district assumed an on-farm efficiency for sprinkler systems of 65 to 80 <br />percent. He also indicated that installation of sprinklers began in 1969. According to <br />Agro Engineering, most of the sprinklers in the valley were installed between 1970 and <br />1980. Prior to that time, almost all farms used flood irrigation methods. <br />Although actual application efficiency can vary with crop type, a consistent maximum <br />application efficiency is recommended throughout the basin based on irrigation method. <br />Table 6 shows the recommended maximum application efficiencies for use in the <br />consumptive use analysis. <br />appendB_cropcu_6-2004.doc B-16 of B-19 12/13/00 <br />