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<br />,I <br /> <br />04G:i <br /> <br />Ground Water <br /> <br />Ground water in the alluvial aquifer occurs in an unconfined state. <br /> <br />Localized confining and perching conditions may be observed due to <br /> <br />the presence of clay lenses. The water table slopes to the South <br /> <br />Platte River from both .the north and south sides of the river. The <br /> <br />shape of the water table contours ,(Hurr, et al, 1975) indicate that <br /> <br />the South Platte River may be cons'idered as a gaining stream throughout <br />~ ' <br />the study area. Depths to water ran~e;f~~ess than 10 feet to about <br /> <br />100 feet and saturated thi ckness range,~'.f~ zero to over 240 feet. <br />.-:;: '~4 <br />,;'.', .~ ~ <br />The aquifer characteristics of interest are transmissivity, permeability, <br />,... , ij <br />" ~ <br />and specific yield. Info~ation r$yarding these parameters may be <br />.-1":-- . ."" <br />found in USGS Water SUP.p.ly"paR~/No. 1378 (1957) and in a series published <br />, ., ,,,. . <br />by the Water Resour es~~s.:i(n of the Geological Survey deali.ng with <br /> <br />the hydrogeologic chara ristics of the valley-fill aquifer of the South <br /> <br />Platte Rivery Valley (Hurr and Schneider, 1972). Transmissivities <br /> <br />determined by pumping tests at six sites in the alluvium ranged from <br /> <br />44,000 gallons per day per day per foot (gal/d/ft) to 290,000 gal/d/ft. <br />Corresponding permeabilities varied from 490 gal/d/ft2 to 3160 gal/d/ft2 <br />(65 ft/day to 421 ft/day). Based on the same pumping tests, the storage <br />coefficients (specific yield) ranged from 0.000082 to 0.179. <br /> <br />In the study area from Fort Morgan to the Colorado-Nebraska State line, <br /> <br />a potential storage capacity in excess of 900,000 acre-feet was calculated. <br />