Laserfiche WebLink
Evaluation of Potential Subsidence Impacts of Longwall Mining in the Spruce Stomp Lease Area <br />to Aquatic Life and Water Supply <br />• Evaluation of existing subsurface data of alluvium and colluvium thickness in the vicinity <br />of the Potential Project. <br />• Weekly monitoring of flow and turbidity with more frequent (twice weekly) sampling for <br />total suspended solids and total dissolved solids until peak flows were observed. <br />• Geologic subsidence modeling. <br />• Post - subsidence channel profile, cross section and habitat modeling. <br />4.0 BACKGROUND AND PHYSICAL SETTING <br />4.1 West Fork Terror Creek Watershed <br />4.1.1 Geographic Setting <br />The Spruce Stomp Lease Area is located in Delta County, Colorado, approximately six miles <br />northeast of the Town of Paonia (see Figure 1). The Potential Project area is located to the <br />northwest of the existing Bowie No. 2 Coal Mine, with potential mine panels to be located in <br />areas underlying West Fork Terror Creek (see Figure 2). At the downstream end of the Potential <br />Project area, the West Fork Terror Creek watershed consists of approximately 19 square miles of <br />land (see Figure 3) owned by the U.S. Forest Service, the Bureau of Land Management and <br />private owners. Downstream of the Potential Project area, West Fork Terror Creek combines <br />with East Fork Terror Creek to form Terror Creek, which is a tributary of the North Fork of the <br />Gunnison River (North Fork). <br />4.1.2 Topography and Land Use <br />The West Fork Terror Creek watershed ranges in elevation from approximately 7,100 feet near <br />the confluence with East Fork Terror Creek up to nearly 11,000 feet at the headwater peaks. <br />Overall, the terrain in the watershed is very steep, with mean watershed terrain slopes of <br />approximately 20 percent (based on 10 -meter data analyzed by USGS StreamStats). <br />121 - 014.000 Wright Water Engineers, Inc. Page 3 <br />January 2013 <br />