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Groundwater Evaluation For Proposed Heit Aggregate Operation Weld County, Colorado 250 gpm for 12 hours a day. Next, the proposed pit was included as a no-flow boundary and the model was run using the results from the base run as a starting point. 4.2.1 Baseline Run The simulated water table elevations for the base run are shown in Figure 2. The pit to the south forms a barrier to groundwater flow and the water table elevations are slightly higher to the south and lower to the north. 4.2.2 Run With Proposed Pit The simulated water table elevations for the condition representing the proposed pit are shown as the deviations from the baseline run in Figure 3. From this, it can be seen that construction of the pit reduces water table elevations to the north of the proposed pit by approximately 3.0 feet, and increases the water table by approximately 2.0 feet on the southwest corner of the pit. At the location of the AWC well (Permit No. 50354-F), the water table elevation is approximately 2.2 feet lower than the baseline run. This represents slightly less than a ]0 percent decrease in saturated thickness for the well. 5.0 DISCUSSION The modeling conducted for this evaluation indicates that construction of the proposed pit will have a minimal impact on water levels at the well owned by AWC immediately north of the proposed pit. The projected lowering of the water table by 2.2 feet represents less than ]0 percent of the estimated saturated thickness of the well and is likely within the range of expected natural water table fluctuations. The relatively small decrease in water levels is due to the permeable nature of the alluvium, which is sufficient to maintain water levels and the yield of the well even with contributions from the aquifer to the south blocked by the proposed slurry wall around the pit. 021-110.030 Wright Water Engineers, Inc. Page 5 March 2003