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Inc the Kammerzell property, which is a reasonable saturated thickness of the alluvial aquifer based on the bore hole data. The hydraulic conductivity of the alluvial sediments was obtained from Colorado Circular No. 11, published by the U. S. Geological Survey and Colorado Water Conservation Board (Wilson, 1965). The publication is a compendium of aquifer tests for the major river systems along the Front Range of Colorado. Seven aquifer tests were identified within an approximate 10-mile radius of the Milliken site. The aquifer tests were conducted on irrigation wells completed within the South Platte River valley at similar depths as the well on the Kammerzell property. The average hydraulic conductivity from the seven tests was 1,050 feet/day. This value was used throughout [he model. A recharge rate of 5.5 inches per year was used in the model. This value is reasonable considering the annual precipitation is 12 to 14 inches per year, there is irrigation in the modeled area, and the depth to groundwater is relatively shallow. STEADY STATE SIMULATION A steady state simulation was performed to produce an equilibrium water table of the model area. The steady state water table is shown on Figure 2. A water table elevation of 50 to 52 feet on the Kammerzell property was simulated. These elevations correspond to a saturated thickness of the alluvial sediments of 50 to 52 feet, which is consistent with data from bore hole logs. Atrows on Figure 2 show the direction of groundwater flow. Groundwater flows from west to east and parallel to sub-parallel to the rivers, which is typical of broad alluvial valleys. IMULATION OF PUMPING WELL The model was then used to simulate pumping of the imgation well on the Kammerzell property. The purpose of this simulation was to provide a water [able map with the well pumping for comparison to a subsequent simulation where the well and slurry wall were simulated. Simulated water levels from the previous model run without the imgation well pumping were used as the starting water levels for this simulation. The well was located based on records from the State Engineer's Office and confirmed with the property owners (personal communication, Mrs. Kammerzell). The well was simulated at a pumping rate of 1,800 gpm under steady state conditions. The simulated water table with the well pumping is shown on Figure 3. Figure 4 shows the simulated drawdown created by the well and resulting cone of depression around the well. Drawdown contours on Figure 4 are in one-foot increments. The total drawdown in [he well was approximately five feet. The one-foot drawdown contour extends radially from the well to distances of 700 to 1,500 feet. SIMULATION OF SL URRY WALL The model was next used to simulate the slurry wall. The purpose of this simulation was to predict the change in pumping water levels in [he irrigation well caused by the slurry wall. Comparison of this simulation to [he previous simulation without [he slum wall would result in the slurry wall's etlect on the irrigation well. The slurry wall was simulated by specifying no-flow boundary conditions to al] cells within the slum wall. A slurry wall essentially isolates the interior from the surrounding groundwater system. Groundwater tlow across the slurry wall is negligible; thus, 2-