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Probable Hydrologic Consequences <br />3. <br />11 <br />5. <br />Effects of sediment pond discharges, <br />diversions and culverts at road crossings on <br />surface water quality. <br />Effects of runoff from reclaimed areas on the <br />quality of streamflow. <br />Effects of runoff from reclaimed areas on the <br />quality of streamflow. <br />TABLE 2.05.6.(3) -1 (CONT.) <br />CONSEQUENCES OF THE LIFE -OF -MINE MINING PLAN <br />FOR THE NEW HORIZON MINING AREA <br />Analysis Results <br />Sediment ponds designed for 10 -year, 24 -hour events. <br />Historic NPDES monitoring have only resulted in one <br />exceedences of TSS. No exceedences of any other <br />required parameter has been observed. Diversions and <br />culverts are designed to adequately convey runoff <br />through and around disturbed areas without contributing <br />additional suspended sediment. <br />Reduced runoff rates and volumes, and lower sediment <br />concentrations and yields. Possible large reductions in <br />runoff due to lower slopes and longer hydraulic lengths. <br />Lower slopes and reclamation practices will result in <br />reduced sediment loads. <br />Reclaimed area runoff waterwill be suitable for livestock <br />drinking water. Runoff from reclaimed areas as <br />measured at NPDES 001 has not degraded the quality <br />of water of receiving streams. <br />Revised September 2014 JR -64) 2.05.6(3) -20 <br />Significance <br />Sediment pond discharge impacts will be negligible <br />because discharges will meet NPDES permit limits. <br />Diversions and culvert impacts will be negligible <br />because they have been designed to minimize erosion <br />and to protect the hydrologic balance. <br />Impacts due to reduced runoff will be negligible due to <br />the relatively small reclaimed basin sizes. Flow in the <br />vicinity of both mining areas is dominated by irrigation <br />return water, not runoff. <br />No short or long term significant impacts. <br />