Orange County NC Website
Browse       Search
30 <br /> The modeled area was <br /> 48s— <br /> ,— discretized by 20,000 square <br /> cells 100 feet on a side. The <br /> top of the model was the land <br /> surface as defined by the 3-ft <br /> s r' DEM. The model comprised <br /> two layers: Layer 1 <br /> represented the regolith from <br /> EXPLANATION the land surface to a uniform <br /> — Modeled steady state Watertable Elevation depth of 55 feet; and Layer 2 <br /> 0 Water Wells <br /> Model Boundary - represented the fractured <br /> Pro'ect Property bedrock from the base of the <br /> s regolith to an elevation of 325 <br /> s^ feet, or an approximate <br /> so thickness of 230 feet. <br /> ')0 The initial hydraulic <br /> conductivity of the bedrock <br /> was set at 0.33 ft/day based on <br /> the analyses shown in Table <br /> 3. The hydraulic conductivity <br /> of the regolith was set at 2 <br /> ft/day based on our <br /> experience with testing of <br /> oW values for the regolith at <br /> similar sites. <br /> $0 The effects of the assumed <br /> 5$5 dewatering for the Hanson <br /> Quarry at the south edge of <br /> =SgD the model shown in Figure 5 <br /> were simulated using a Drain <br /> N f,/ boundary condition with a <br /> constant drain invert <br /> 500250 0 500 1,000 1,500 2,000 <br /> Fee, s a Sss elevation of 470 feet and a <br /> f conductance of 500 ft/day. <br /> 4�5 <br /> Figure 5.--Model area and modeled steady state watertable elevations with no pumping from project wells. <br /> Recharge to the model was computed using the USDA Soil and Water Assessment Tool (SWAT)model. <br /> This model simulates a water balance of the soil zone using daily precipitation as input and outputs by <br /> evapotranspiration ET, surface runoff, and deep percolation below the root zone when the soil moisture <br /> holding capacity of the soil is exceeded. The deep percolation is routed to the watertable and becomes <br /> recharge to the watertable surface. Soil moisture storage capacity used for the model was from the <br /> 5 <br />