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• Imports <br />Transbasin imports to the South Platte River from the studies ranged from 400,000 acre-feet per <br />year (400 kaf/yr) (1970) to 426 kaf/yr (1947-1970). <br />• Ground Water Inflows <br />Ground water inflows in the studies were available from the High Plains aquifer to the South <br />Platte River alluvial aquifer below Henderson (75 kaf/yr, Bittinger et al.). Upper South Platte <br />River basin ground water inflows to lower South Platte River study areas were provided in other <br />studies, e.g., 22.8 kaf/yr between Balzac and Julesburg -Water District 64 (1947-1970) and 81 <br />kaf/yr to South Platte River alluvial aquifer below Henderson (1968-1972). <br />Ou bows <br />• Agricultural Consumptive Use <br />The estimates of agricultural consumptive use (CU) in the studies appear to generally be based <br />on a Blaney-Griddle analysis of crop water requirements. Unit agricultural CU rates in the <br />studies range from 1.15 acre-feet per acre to 1.97 acre-feet per acre. The variability in crop CU is <br />attributable to different study periods, different study areas, different irrigated acreage estimates, <br />and different crop water requirements. <br />• Municipal, Commercial, and Industrial (M&I) Consumptive Use <br />M&I CU were not consistent between the studies, which indicated a drop in total M&I use over <br />time (227 kaf/yr in 1982 to 186 kaf/yr in 1995). These estimates cannot be directly compared <br />because they encompass different study periods, different study areas, and/or different <br />methodologies used in the estimates. <br />• Livestock Consumptive Use <br />Livestock CU from the USGS data (1995) totals approximately 20 acre-feet. This value was <br />estimated based on 1995 county agricultural statistics and per-head use rates of 10, 3, and 2 <br />gallons per head per day for cattle, hogs, and sheep, respectively, and a 100 percent CU rate. <br />• Reservoir Evaporation <br />Reservoir evaporation was included in three studies for different study areas. The USGS estimate <br />(1995) for the entire South Platte River basin (223 kaf/yr) is considered the most representative <br />estimate of reservoir evaporation in the basin. The total surface areas and evaporation rates used <br />to calculate reservoir evaporation were not discussed in these studies. <br />• Native Vegetation Consumptive Use <br />Native vegetation CU estimates were identified in three studies (Bittinger et al., Hurr et al., and <br />Morel-Seytoux & Restrepoi (MSR)). Each study used a potential CU rate of 2.67 feet per year <br />for phreatophytic species. The Hurr et al. study (1947-1970) was the only study of the three <br />identified that presented native vegetation CU of non-irrigated lands (279 kaf/yr) within the <br />alluvium exclusive of phreatophytes (163 kaf/yr). <br />• Surface Water Ou flows <br />Task82 final.doc 6 of 7 Apri17, 2005 <br />