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Long -term impacts will center on the effects of subsidence under Scullion <br />Gulch and Red Wash. See the subsidence section of this document for <br />further discussion of subsidence impacts. <br />Small short-term surface water losses will occur as a result of two factors: <br />retention of water in ponds and removal of water from the White River <br />lagoon. Runoff from disturbed areas will be routed through sedimentation <br />ponds, thereby reducing the amount of flow to the White River. Evaporation <br />losses will occur, as the ponds will not discharge runoff until the point of <br />available storage volume is achieved. Clay subsoils, which comprise the <br />bottom of the sedimentation ponds, will allow very little impounded water to <br />re -enter the ground water system. Losses from the D -Portal pond will be <br />insignificant when compared to total runoff from the Scullion Gulch <br />watershed. Scullion Gulch has a contributing drainage area of 7,552 acres at <br />its confluence with the White River, with the D -Portal pond designed to store <br />runoff from only 44 of the acres. The refuse disposal area ponds are <br />designed to receive runoff from approximately 98 acres, which is a small <br />portion of the 2,950 acres drained by the Red Wash tributary through the <br />northern section of the permit area. Based on the above information, the net <br />loss of surface water quantity to Red Wash and the White River will be <br />negligible. <br />Water for the Deserado Mine is supplied by the White River. Combined <br />water use and evaporative loss at full production is projected to consume 552 <br />acre -feet per year at a withdrawal rate of .763 cubic feet per second, which <br />translates to less than .02 percent of the White River's average annual flow of <br />672 cubic feet per second. During low flow conditions of the White River, <br />the withdrawal rate will be 0.31 percent of the available flow. Therefore, the <br />adverse impacts on the flow in the White River as a result of the withdrawal <br />should be minimal. <br />The construction of surface facilities in the permit area will cause temporary <br />increases in the amount of suspended solids in the surface water system. <br />Concentration of elemental constituents such as iron and manganese will also <br />increase. Mitigation of sediment load will be accomplished primarily by <br />sedimentation ponds. Although sediment increases will occur in the early <br />phases of construction, the long -term sediment yield may decrease below the <br />already high natural occurrence of sediment concentrations due to the <br />installation of control measures. <br />Effects on the surface water system from the refuse disposal area should be <br />minimal. Analysis of the waste material does not indicate the presence of <br />toxic or acid - forming characteristics. The waste will be covered with 30 <br />inches of non - toxic, non - combustible material, thereby reducing the <br />infiltration of water into the pile and further reducing the potential for water <br />quality degradation. The size of the non - reclaimed disturbed area at the <br />32 <br />