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Page 3-78 Environmental Analysis February 2000 The criteria for significant impacts refer to adverse impacts to the quality or quantity of groundwater utilized for important uses such as domestic water supply, livestock watering, springs that recharge wetland/riparian areas or support wildlife habitat, and natural resource values. It is important to note that subsidence induced impacts to groundwater resources were calculated from the reasonably foreseeable development scenarios and generalized overburden strata characteristics for the Iron Point and Elk Creek Coal Lease tracts. It was also assumed that coal would be extracted to the limits of the lease tract boundaries using longwall mining techniques. Actual mining plans could be different. Exploration activities.should not noticeably impact groundwater resources. The strata are not uniformly saturated, so there is little concern for inter-aquifer communication. The drill holes would be of small diameter and would cause little disturbance to the geologic strata. 3.6.3.1 Effects of Alternative A (No-Action) Direct Effects -Under this alternative, the coal lease tracts would not be offered for lease, and mine development would not occur. AS a result, there would be no mining related impacts to groundwater resources in the Iron Point and Elk Creek Coal Lease tracts or from exploration activities in the Iron Point exploration license area. Existing impacts to groundwater from past and current land uses would continue. The Bowie No. 2 Mine and Sanborn Creek Mine would continue to operate under their current permits. The Bowie No. 2 Mine would develop north and east to the proposed Iron Point Coal Lease Tract boundary. As a result of this development, there is potential for subsidence related impacts to groundwater resources. Several seasonal springs in this area could be impacted including S-8 and S-13 (see Figure 14, Subsidence Potential Map). The Bowie No. 2 Mine is expected to be dry, and no impacts to groundwater resources from dewatering are expected. Oxbow would develop the Elk Creek Mine on fee (private) coal reserves. As a result of this development, there would be the potential for subsidence and dewatering related impacts to groundwater resources. The subsidence impact evaluation completed for this document indicates potential impacts to groundwater resources near the D seam outcrops in Bear and Elk creeks. Several seasona! springs in this area could be impacted including the Elk No. 1 (see Figure 14, Subsidence Potential Map). Dewatering could temporarily disrupt local groundwater recharge and discharge. The regional groundwater flow gradient in the area is to the northeast. Theoretically, groundwater flow in the D coal seam in the Elk Creek Mine area discharges to some point outside the north Fork of the Gunnison drainage basin area. Mine development may require dewatering of the D coal seam and the water would be discharged to the North Fork of the Gunnison. This may represent a transbasinal diversion of groundwater. After mining, the mine voids would fill with groundwater to near pre-mining levels. The groundwater would be exposed to collapsed and abandoned mine workings, and the quality of the water may be impacted. The most likely impact would be an increased concentration of TDS, iron, manganese, and possibly sulfate. The groundwater flow direction in the D seam horizon is to the northeast beneath Grand Mesa. There are no known wells or springs down- gradient of the Elk Creek Coal Lease Tract that would be affected by any possible groundwater degradation. Final Environmental Impact Statement