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<br />.' , <br /> <br />e <br /> <br />e <br /> <br />e <br /> <br />u[ji/,W~ <br />Task 1.1~ - fvaluation of Consumptive Use Models <br /> <br />Irri!!ation Water Reauirement (IWR) <br /> <br />The consumptive irrigation requirement is the depth of irrigation water required <br />consumptively for crop production, exclusive of effective rainfall and carry over soil <br />moisture. <br /> <br />IWR ~ CCU - (ER + SM) <br /> <br />(1) <br /> <br />Farm Loss (FU <br /> <br />Farm loss is the total of incidental losses which occur during irrigation such as deep <br />percolation, run-off, and/or water applied for leaching. <br /> <br />Farm Headl1ale Requirement (FHR) <br /> <br />The depth of irrigation water, exclusive of precipitation, stored soil moisture or ground <br />water, that is required consumptively for crop production and required for other related <br />uses such as leaching, frost protection, etc. <br /> <br />FHR ~ CIR +FL <br /> <br />(2) <br /> <br />Convevance Loss (CU <br /> <br />Conveyance loss is the total of all the losses which occur from the diversion source (river <br />headgate) to the farm headgate. These losses include seepage and evaporation. <br /> <br />River Head!!ate Reauirement (RHR) <br /> <br />The volume of water required to fully satisfy the on-farm losses, potential <br />evapotranspiration of the crop, and the conveyance Josses. <br /> <br />RHR = FHR +CL <br /> <br />(3) <br /> <br />On-farm Irri!!ation Efficiencv (Ef) <br /> <br />On-farm irrigation efficiency is the irrigation efficiency as measured from the farm <br />headgate, <br /> <br />CIR <br />%Ef = FHR x 100 <br /> <br />(4) <br /> <br />Convevance Efficiencv (Ec) <br /> <br />Conveyance efficiency is the ratio of the volume of water delivered in an open or closed <br />conveyance system at the supply source which could be a head gate or well head. <br /> <br />%Ec = FHR x 100 (5) <br />RHR <br /> <br />Svstem Irri!!ation Efficiencv (Es) <br /> <br />System irrigation efficiency is the irrigation efficiency as measured from the point of <br />diversion. This is the ratio of volume of irrigation water required for beneficial use in the <br />specified irrigated area to the volume of water required to be delivered to this area to <br />achieve the specified amount of beneficial use, <br />%Es ~ CIR ~ [EfXEC] 100 <br />o RHR 100 x <br /> <br />(6) <br /> <br />10/6/94 - CUModel Terms (1.14-8) <br /> <br />2 <br /> <br />IDS Group, CSU <br />