Laserfiche WebLink
4. Water supply-limited consumptive use was determined by including diversion <br />records, conveyance efficiencies, application efficiencies, soil moisture interactions, <br />and supplemental ground water supplies. Pumping in the basin is not generally <br />known, therefore, pumping was estimated through the model analysis. For most ditch <br />systems, the model determined water supply-limited consumptive use and ground <br />water pumping in the following general sequence, termed the "mutual ditch" <br />approach: <br />Surface water was applied to meet irrigation water requirements for all land under <br />the ditch system. If excess surface water still remained, it was stored in the soil <br />moisture reservoir. <br />If the irrigation water requirement was not satisfied, surface water stored in the <br />soil moisture reservoir was used to meet remaining irrigation water requirements. <br />If the irrigation water requirement was still not satisfied, ground water was first <br />pumped to meet remaining irrigation water requirements for sprinkler irrigated <br />lands identified as having a ground water source, up to the maximum permitted or <br />decreed pumping capacity. If pumping capacity was not exceeded, ground water <br />was then pumped to meet remaining irrigation water requirements for flood <br />irrigated lands identified as having a ground water source, up to the remaining <br />pumping capacity. <br />Based on information from water users and administrators, the following large ditch <br />systems were identified as using ground water through their sprinklers, and applying <br />surface water on lands without sprinklers: <br />• Rio Grande Canal <br />• Farmers Union Canal <br />• Prairie Ditch <br />• Excelsior Ditch <br />The model determined water supply-limited consumptive use and ground water <br />pumping for these ditch systems in the following general sequence, termed the <br />"maximum supply" approach: <br />• Ground water was pumped to meet irrigation water requirements for sprinkler <br />irrigated lands identified as having a ground water source, up to the maximum <br />permitted or decreed pumping capacity. <br />• Surface water was applied to meet irrigation water requirements for lands without <br />a ground water source. <br />• Remaining surface water was applied to meet irrigation water requirements for <br />flood irrigated lands identified as having a ground water source. If excess surface <br />water still remained, it was stored in the soil moisture reservoir. <br />• If the irrigation water requirement was not satisfied on lands receiving surface <br />water, surface water stored in the soil moisture reservoir was used to meet <br />remaining irrigation water requirements. If irrigation water requirement was still <br />not satisfied, then ground water was pumped to meet any remaining demand on <br />flood irrigated lands with a ground water source, up to the maximum permitted or <br />decreed pumping capacity. <br />cureport_6-2004.doc 14 of 48 June, 2004 <br />