Land degradation assessment for an abondoned coal mine with geospatial information technologies

Emil, Mustafa Kemal
This study proposes an approach for land degradation assessment for an abandoned coal mine by using geospatial information technologies. The land degradation assessment focuses on two major changes: topographical and Land Use and Land Cover (LULC). For this purpose, stereo aerial photos, Worldview-1, Landsat and ASTER images, Terrestrial Laser Scanning (TLS) data, Global Positioning System (GPS) data, and ancillary maps were used for abandoned Ovacık surface coal mine. Volume of excavations and fillings, drainage network deviations, and slope instabilities were the investigated topographical disturbances by comparison of the Digital Elevation Models (DEM) for pre- and post-mining stages. Using aerial photos and Worldview-1 satellite image, LULC maps were prepared based on the same time period. Then areal extent and spatial pattern of the LULC change was calculated and mapped by post classification comparison method. The results of land degradation assessment show that there was a significant topographical disturbance and LULC change in the research area. Particularly, three dump areas with a total volume of 2,334,878 m3 were identified by DEM subtraction. It was found that stream network around the primary dump site shifted towards south with a maximum displacement of 60m. Slope analysis reveals that slopes higher that 60 degrees were mainly observed in excavation area with 81 percent. LULC change study showed that the forest area decreased an amount of 106,485 m2 from 1951 to 2008. However; by means of the forestation efforts in dump sites, an amount of 106,012 m2 forest land was recovered.