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<br />. <br /> <br />. <br /> <br />. <br /> <br />slice of the aquifer as opposed to full cylindrical rings, reqUlnng slightly different <br />corrections for changing properties w~h increasing distance from the well. Cell widths <br />vary from 1 foot near the well to 56,69 feet beyond 340 feet from the well. Distance <br />from the well to the model boundary is 3969 feet. <br /> <br />All model layers are defined as confined or unconfined depending on the <br />calculated water level in the layer. As water level in the aquifer falls below the top of <br />the aquifer, the layers convert from confined to unconfined conditions. If water level in <br />a cell falls below the base of the aquifer in that cell, the cell is allowed to go dry. <br /> <br />One requirement in this project is that regional heads calculated by Banta's <br />simulation be maintained in the radial flow model so that water levels calculated in and <br />near the well correctly reflect the simulated changes in the regional flow system. <br />Referring again to the Trescott approximation, we see that at a distance from the well <br />equal to the effective radius, head in the cell should match head in the aquifer. This <br />relationship is shown in Figures 4,' and 4.2 discussed earlier. Effective radius (re) is <br />calculated as: <br /> <br />re; r1/4,81 <br />where, r1 ; cell width. <br /> <br />In the Banta model. cells at the locations of interest are square with cell width 1.5 miles. <br />For a cell width of 7920 feet (1.5 miles), we would expect to match water level in the cell <br />at a distance of 7920/4,81 = 1646 feet, in column 50 of the radial model. A general <br />head boundary was set in column 90 of the radial model and adjusted so that head in <br />column 50 would match the appropriate water level from Banta's results. Some trial <br />and error was required to properly set the boundary conditions through time, <br /> <br />In some locations where water level changes resulted in significant reductions in <br />saturated thickness, pumping rates from Banta's model could not be maintained from a <br />single well. In these cases, the simulations were continued as if additional wells were <br /> <br />17 <br />