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i <br /> the operator proposes a mitigation plan that is intended to restore groundwater elevations back to <br /> historic conditions before lined reservoirs were constructed. <br /> The operator proposes to install a French drain system around the perimeter of the property to <br /> intercept groundwater flows and maintain an avenue to route the flows around the reservoir. <br /> This French drain will be very similar to the field drains that are used by farmers to control high <br /> groundwater in agricultural fields. An estimate of the flow in the aquifer indicates that a French <br /> drain with a capacity of 2 efs would be adequate to maintain groundwater levels in the area. <br /> Approximately 5,000 linear feet of 12" diameter perforated PVC pipe would be used with a <br /> gravel encasement and geotextile cloth (see Figure G-1). The drain would be constructed to a <br /> maximum depth ranging of 8 feet and would be daylighted to allow for flows to escape as surface <br /> water in the event that the aquifer has no capacity downstream of the property. It is theorized <br /> that in most situations, the downstream aquifer will have excess capacity due to the reservoir <br /> liner construction and that flows in the drain will gradually return back to the aquifer through the <br /> perforations and gravel drain. In normal conditions, there should be not water flowing at the end <br /> of the drain which would protect groundwater users downstream and would not reduce available <br /> supplies to either surface or groundwater users. <br /> Project Water Requirements <br /> The proposed mining operation will consume water from plant operations, minor evaporation <br /> from exposed groundwater during dewatering operations, and moisture loss in materials <br /> transported from the site. <br /> The water losses will be accounted for in an approved Substitute Water Supply Plan (SWSP) <br /> submitted to the State Engineers office. A copy of the approved plan will be submitted to DMG <br /> when it is received. <br /> Table G-1 summarizes annual consumptive use estimates <br /> Table G-1 Annual Consumptive Use(acre-ft) <br /> Annual <br /> Description Volume a <br /> Evaporation 0.67 <br /> Moisture Retained in Material 7.35 <br /> Dust Control 0.80 <br /> TOTAL: 8.82 <br />