2008-06-09_REVISION - C1980007 (3)

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Water Fork and Lower Dry Fork Alluvial. wells. Based on water quality data provided in the West Elk Mine 2005 Annual Hydrology Report, water quality for alluvial/colluvial ground water aquifers and shallow perched ground water is colntnonly similar to surface water quality (HydroGeo 2006). Recharge to these shallow aquifers occurs through stream flows under high. flow conditions and direct infiltration of runoff from precipitation and snowmelt. Under low flow conditions, the saturated alluviaUcolluvial deposits in the larger drainages discharge water to the stream channel (ground water recharge), supplying perennial surface water flows via springs and seeps. Given the semi-arid conditions in the area and relatively steep stream gradients, many of the smaller drainages do not receive enough recharge to maintain year-round surface flow. Bedrock ground water resources in the project area are limited to isolated perched lenses and fracture/fault zones. There are several bedrock groundwater monitoring wells in the project area that are monitored by the West Elk Mine hydrologic program. These wells are sampled three times per year for field parameters and water level and once per annum for laboratory water quality analysis for parameter specified in the hydrologic monitoring program. Age- dating chemical analyses from the West Elk monitoring program have shown that bedrock groundwater resources in the vicinity of the mine are part of a deep inactive system that is not in direct contact with near-surface water (USDA F S 2003a). Deeper perched ground water and any ground water associated with the coal seams that have been in contact with shale and mudstone may exhibit elevated levels of total dissolved solids (HydroGeo 2006). Groundwater may also be present to a limited extent within coal seams. Bedrock and associated coal seams dip to the northeast, with the uppermost strata outcropping along the North Fork Valley. The occurrence of groundwater springs in the North Fork outcrops of the Mesa Verde formation is rare. BLM and MCC report that the coal seams in the West Elk Mine area are typically dry, with average moisture content of 5 percent. Groundwater discharges from faults intercepted by longwall panels in the West Ellc Mine have experienced initially high volume discharge periods followed diminishing to negligible flow within a short time period. No effects on surface water resources have been documented from interception of water-bearing faults underground. Not all faults encountered during mining have contained water. Mine underdrain and mine inflow sites are currently monitored for flow and water quality by the West Elk hydrologic program. The total inflow for the West Elk Mine is approximately 200 acre-feet per year (HydroGeo 2006). Direct and Indirect Effects Alternative 7 Surface Water Under the no action alternative, current management plans, existing coal recovery related, and non-coal related activities would continue to occur and/or guide management of the project area. Since additional mining- related surface disturbances would not occur, or would be limited to surface resource monitoring activities such as monitoring wells, surface water monitoring stations, etc., Alternative 1 would have no or negligible effects on surface water resources. Ground Water Under Alternative 1, current management plans and non-coal related activities would continue to occur and/or guide management of the project area. Since mining-related subsurface disturbances would not occur, or be limited to surface resource monitoring activities such as monitoring wells, surface water monitoring stations, etc., Alternative 1 would have no or negligible effects on ground water resources. Deer Creek Ventilation Shaft and E Seain Methane Drainage Wells FEIS 65