The Mountain Top Removal (MTR) method of coal mining in the Appalachian Mountains has been shown to impact the surrounding hydrology (Petrequin). As part of the study of applying GIS to MTR impacts, this project included creating stream and basin features. This was done by mosaicking four DEMs into one layer and then applying several Spatial Analyst Hydrology tools.
Analyzing the impact of the MTR method of coal mining on an area involved comparing imagery from two different time periods. ArcMap and ERDAS Imagine were both used with 2005 imagery to develop a signature file which was then applied to 2010 imagery to develop a map of MTR areas.
Only a portion of the 2010 data was analyzed by Group 3 for SkyTruth. The 7 bands of the 2010 Landsat imagery were consolidated using the Composite Bands tool, and the imagery was clipped to the group's study area in ArcMap. A layer with 50 classes was created in ERDAS Imagine using the Unsupervised Classification tool. Areas which appeared to be part of MTR were classed and symbolized by color accordingly with the remaining areas being classed as NonMTR. Many objects such as stream or river banks, buildings, and roads have identical spectral signatures as MTR and were included initially. They were removed from the MTR features later. In ArcMap, the classified image was reclassified with MTR being assigned a value of 1 and all other Class Names assigned blank values.
From this information, the MTR raster was converted to polygons. MTR features within 400 meters of major rivers or highways were removed from the MTR polygon layer, as were those within 50 meters of streets and other rivers. Features smaller than 40 acres were removed as well. An accuracy assessment was done with a result of 96.7%, and a comparison against the 2005 dataset was made. There was an overall decrease in acreage attributed to MTR from 2005 to 2010, but the data needs to be critiqued further. The 2005 dataset included features of less than 40 acres, while the 2010 data was restricted to features containing more than 40 acres. The 2005 dataset had more than 8,000 features, while the 2010 dataset had fewer than 500 due to the acreage restriction.
A layer package was created with this data and submitted to the group leader for compilation into one dataset for the group's study area, and a map service to present the group findings online was created. This map service was used to create an online map. A soils runoff classification layer was also added to the map. This additional data was selected because runoff from MTR sites impacts the surrounding areas. The online map can be viewed here, although the soils layer is not available to all viewers.
Resource:
Petrequin, M. (2012). Hydrological Impacts of Mountaintop Removal in Appalachia: History and Solutions (Colorado School of Mines, Department of Environmental Science and Engineering). Retrieved from uwf.edu.
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