Laserfiche WebLink
Third White Sandstone emanating from the mined area will flow in a westerly direction along the axis of <br />the Big Bottom syncline. No currently existing adjudicated wells are expected to be impacted by the <br />potential development and migration of this plume. Water quality in the Third White Sandstone will not be <br />degraded to the point it is no longer suitable for current uses. <br />Water from rain and snowmelt that infiltrates the Horse Gulch Fill is not expected to significantly infiltrate <br />bedrock stratigraphic units underneath the fill because the bedrock units have low permeability and the fill <br />is constructed on sloping land which should cause the water to flow to the toe of the fill where it will <br />discharge to the surface. <br />4.8.3.3 Post Mine Hydrolooic Balance <br />Precipitation amounts are expected to be similar to pre -mine conditions after mining. Section 2.7.6.1 <br />discusses pre -mine precipitation. Evapotranspiration is likely to be less during the first few years after <br />mining because the decrease in vegetative cover should decrease transpiration. Evapotranspiration <br />should approach the pre -mine values as vegetation is re- established. <br />If recharge to the spoils is larger than pre -mine values, direct surface runoff will be reduced subsequent to <br />mining. A larger net groundwater discharge to the surface system is likely in areas where spoil springs <br />develop. These discharges could offset a decrease in direct surface runoff from the reclaimed surfaces. <br />The larger amount of groundwater discharge to springs will increase the water availability for wildlife and <br />livestock in the area for a greater portion of the year. <br />4.8.4 Impacts to Potential Alluvial Valley Systems <br />Little potential exists for impact to the Williams Fork alluvial system because very little surface water and <br />essentially no groundwater from the proposed mine plan area flow toward the Williams Fork River. <br />Section 2.7.7.1 should be consulted for details. The potential for impact to the Yampa alluvial system is <br />very small because the Upper Williams Fork aquifers yield only a very small percentage of the water in <br />this system. Additional information on the Yampa River alluvial system is given in Section 2.7.7.2. <br />Potential alluvial valley floors in the drainages leaving the proposed mine plan area are addressed in <br />Section 2.7.7.3. <br />The definition of the geologic control of groundwater movement at one of the potential AVF sites will typify <br />4 -238j <br />- rR l C'4 <br />6 112, 106 <br />