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RULE 2 PERMITS <br />South Taylor Pit Hydrology -The South Taylor pit will have a reclaimed surface azea of approximately <br />1004 acres and a pit bottom that inclines predominantly towazds the Good Spring Creek drainage (Figure <br />2.05.6-1). Assuming resaturation would raise a pit aquifer level to 7,500 feet AMSL (the elevation of the <br />lowest point on the southeastern pit boundary) and considering the pit topogaphy, the volume of <br />materials that must be resaturated is calculated to be 6.92 x 108 cubic feet (fr'). Assuming 20% effective <br />porosity, 1.38 x 108 ft3 of water (3,178 acre-feet) must infiltrate from the surface and from the Williams <br />Fork Formation to fill the pit to this level. <br />Prior to flow from a pit, resaturation of the materials in the pit must occur. The time necessazy for the <br />resaturation of the backfilled pit can be estimated by utilizing the volume of the pit, the infiltration rate, <br />and the porosity of the materials within the pit. Published infiltration rates for the area aze 0.5 inches per <br />year (Rice, 1979) and 3 inches per yeaz (Williams & Clark, 1992), for an average value of 1.8 inches per <br />year. Calculated inflows, in the above equations, indicate an inflow rate 92 gpm (approximately 150 <br />acre-feet/yeaz from 1.8 inches infiltration over 1,000 acres) from infiltration due to precipitation. (No <br />other water is expected to flow into the reclaimed pit materials since the South Taylor Pit is on a <br />topographic and structural high). The volume of water needed to fill the reclaimed pit divided by the <br />infiltration rate equals the time to fill the pit to form an aquifer necessary for sufficient outflow. The <br />result of this calculation is approximately 45 yeazs for pit resaturation to the elevation of the lowest point <br />of the pit boundary where water could be dischazged. This assumes no water infiltrates into the <br />undisturbed Williams Fork Formation on the limits of the reclaimed pit, and the entire pit fill becomes <br />saturated. It is possible that the pit fill will be anisotropic and heterogeneous in a way that can allow a pit <br />spring to form prior to complete saturation of the pit fill. It is also possible that most or all of the pit <br />water will enter the Williams Fork Formation (see discussion below) thereby reducing the time to reach <br />satwation or preventing the full thickness from becoming saturated. <br />~~ <br /> <br />South Taylor/t.ower Wilson- Rule 2, Page I15 Revision Date: 3/30/07 <br />Revision No.: PR-02 <br />