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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />0006G8 <br /> <br />4.2 Theory and Discussion of Recharge Basin Model, CSUPAW <br />The goal of the recharge basin is to increase the groundwater table <br />beneath adjacent wet meadows to an appropriate level of approximately 1 to 1.5 <br />feet beneath the soil surface prior to whooping crane and sandhill crane <br />migration (Nebraska Water Resources 1995). Wet meadows are associated <br />with vegetation types requiring soils which are sub irrigated by a high water table <br />and/or saturated by seasonal flooding. Cranes utilize this habitat for their <br />invertebrate food supply as well as for social and behavorial activities (Wesche <br />et. al. 1994). <br />The mathematical analysis that was used to describe the effect of the <br />recharge basin on the groundwater levels and the associated groundwater <br />mound beneath a rectangular recharge basin involved Glover's method. Glover, <br />a professor at Colorado State University in the 1960's, developed a method to <br />describe the constant recharge rate for a rectangular basin and the resulting <br />groundwater mound. <br />A microcomputer model of artificial recharge that is based in part on <br />Glover's solution was introduced in 1984 called Colorado State University fit <br />!nd Well, or CSUPAW(Warner et. al. 1984). The CSUPAW software allows <br />the user to calculate the response of a water table to artificial recharge applied <br />with rectangular basins. In addition, the model calculates the amount of <br />recharge water returning to the stream in a stream aquifer that exists in the <br />central Platte River basin. Version 3.0 released in 1988 was used for this study. <br />The use of this model for the analysis of the proposed recharge basin <br />required the following assumptions to be made: <br />1. Aquifer was homogeneous and of infinite areal extent <br />2. Aquifer was isotropic and unconfined <br />3. Recharge rate was held constant <br />4. Water table beneath recharge basin was initially horizontal <br />The aquifer beneath these wet meadow sites is not entirely comprised of the <br />same geologic material and is, therefore, not a homogeneous aquifer. However, <br /> <br />10 <br />