A Remote Sensing Approach to Environmental Monitoring in a Reclaimed Mine Area

• Published in: ISPRS international journal of geo-information 2017-12, Vol.6 (12), p.401
• Main Authors: Padmanaban, Rajchandar, Bhowmik, Avit, Cabral, Pedro
• Format: Article
• Language: English
• Subjects: Aquifers; Collision dynamics; Data mining; Deformation; Deformation mechanisms; Dynamics; Environmental changes; Environmental impact; Environmental management; Environmental monitoring; Flooding; Geology; Ground motion; Groundwater; Groundwater table; Growth; Image classification; land cover change; Land reclamation; Land use; Landsat; Landsat satellites; Landscape; mine reclamation; Mining; Mitigation; NDVI; Normalized difference vegetative index; post-mining; Productivity; Random forest classification; Reclamation; Remote sensing; Shape memory alloys; Soil; Spectral Mixture Analysis; Subsidence; Substrates; Surface area; Vegetation; vegetation productivity; Water table; Wetlands
• ISSN: 2220-9964; 2220-9964
• DOI: 10.3390/ijgi6120401

Mining for resources extraction may lead to geological and associated environmental changes due to ground movements, collision with mining cavities, and deformation of aquifers. Geological changes may continue in a reclaimed mine area, and the deformed aquifers may entail a breakdown of substrates and an increase in ground water tables, which may cause surface area inundation. Consequently, a reclaimed mine area may experience surface area collapse, i.e., subsidence, and degradation of vegetation productivity. Thus, monitoring short-term landscape dynamics in a reclaimed mine area may provide important information on the long-term geological and environmental impacts of mining activities. We studied landscape dynamics in Kirchheller Heide, Germany, which experienced extensive soil movement due to longwall mining without stowing, using Landsat imageries between 2013 and 2016. A Random Forest image classification technique was applied to analyze land-use and landcover dynamics, and the growth of wetland areas was assessed using a Spectral Mixture Analysis (SMA). We also analyzed the changes in vegetation productivity using a Normalized Difference Vegetation Index (NDVI). We observed a 19.9% growth of wetland area within four years, with 87.2% growth in the coverage of two major waterbodies in the reclaimed mine area. NDVI values indicate that the productivity of 66.5% of vegetation of the Kirchheller Heide was degraded due to changes in ground water tables and surface flooding. Our results inform environmental management and mining reclamation authorities about the subsidence spots and priority mitigation areas from land surface and vegetation degradation in Kirchheller Heide.