Laserfiche WebLink
• The result~of the calculation is an expected annual percolation amount of 1.6 cm. <br />This means that over a long period of time, [he most probable percolation rate is <br />1.6 cm/yr. <br />Subsequent to these calculations, the unsaturated zone travel time was calculated <br />per the following example: <br />Most probable long-term percolation rate = 1.6 em/yr <br />(from groundwater recharge calculations) <br />Average depth to water in the Upper Williams Fork = 185 feet (56.40m) <br />(refer to Section 2.7) <br />Maximum depth of pit = 140 feet (42.67m) <br />~ Thickness of waste = 35 fee[ (10.67m) <br />Thickness of spoil = 105 feet (32.OOm) <br />Thickness of [he unsaturated Upper Williams = 45 feet (13.72m) <br />Fork below [he 140 foot deep pit bottom <br />(185 feet - 140 feet = 45 feet) <br />Available soil moisture capacity <br />Waste - 25 cm/m x 10.67 m = 265.8 cm <br />Spoil - 20 cm/m x 32.00 m = 640 cm <br />Unsaturated Upper 'Ailliams Fork below the pit bottom - <br />20 cm/m x 13.72 m <br />cm = 274.4 cm <br />226.8 cm + 640 cm + 274.4 cm = 1181 cm <br />Expected time before percolating water will recharge groundwater = <br />1181 cm '^ 740 years <br />1.6 cm/yr <br />4-50 <br />