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BLM Uncompahgre Field Office <br />3.12.1.2 Groundwater Resources <br />Sunset Trail Area Coal Exploration Plan EA <br />Shallow groundwater resources are limited due to geomorphic controls imparted from the relatively <br />steep gradients and stream profiles of drainages in the area, resulting in relatively thin <br />alluvial /colluvial deposits confined to the bottoms of drainages. Groundwater that surfaces as <br />springs and seeps in the tracts is associated with these shallow alluvial/colluvial deposits and does <br />not appear to be hydrologically connected with deeper bedrock aquifers. <br />Groundwater may also be present to a limited extent within coal seams. Bedrock and associated <br />coals dip to the northeast with the uppermost strata outcropping along the North Fork valley. The <br />occurrence of groundwater springs in the North Fork outcrops of the Mesa Verde formation are <br />rare. <br />3.12.2 Environmental Consequences <br />3.12.2.1 Proposed Action <br />Direct and Indirect Effects <br />Surface Water <br />Surface disturbance of approximately 30 acres would occur from roads and drill pads. Stipulations, <br />erosion control, and use of BMPs proposed in the coal exploration plan will minimize the potential <br />for erosion and subsequent sedimentation into streams. However, even with implementation of <br />these management practices, some soil loss may occur and some surface water may temporarily <br />exhibit increased sediment loads. <br />Seven riparian crossings are anticipated to access drilling sites. Culverts will be used for stream <br />crossings to minimize impacts from sediment. Riparian crossings are in compliance with the lease <br />stipulation because no practical alternatives exist. <br />Roads and drill pads will be reclaimed following Forest Plan standards and guidelines. With respect <br />to previous surface disturbances on nearby leases, revegetation has been observed to be generally <br />successful between two and five years after reclamation work is completed. <br />Through leasing stipulations, disturbances on soil types with high erosion or mass movement hazard <br />are prohibited, so the project is less likely to result in increased erosion or trigger landslides. The <br />GMUG Forest Plan (USFS, 1991), and the Forest Service Watershed Conservation Practices <br />Handbook calls for limiting ground- disturbing activities on unstable slopes and highly erosive areas. <br />Due to the watershed related lease stipulations proposed for exploration areas, and the adherence to <br />Forest Service policy, these areas will be avoided. <br />Ground Water <br />The proposed exploration drilling is not expected to encounter any water bearing fault zones or <br />significant groundwater inflows. Drilling locations are required to be completed in a manner that <br />would protect groundwater resources from contamination. No impacts on groundwater are expected <br />from exploration activities. <br />Cumulative Effects <br />Current mining activity at the West Elk Mine has had no discernible localized effects to stream <br />morphology, erosion rate, or suspended sediment load. High flows in intermittent and ephemeral <br />June 2013 28 <br />