Remote Sensing Data and Indices to Support Water Management: A Holistic Post-mining Approach for Lignite Mining in Greece

Entering the coal phase-out era, major priorities of the Greek lignite mining industry are sustainable mine closure, land reclamation, and planning for long-term and sustainable land repurposing scenarios. A holistic and digitally enabled approach to water management could lead to effective strategic planning in the coal phase-out era. This research proposes an integrated approach to evaluate the hydrological profile of a large and complex open pit lignite mining area based on remote sensing data. This framework included processing of satellite images in different bands and an evaluated digital elevation model of an ≈170 km2 area within the Ptolemais Basin, northern Greece, that has extensive surface lignite mining. Several spectral (SMI, RIP, NDVI, NDWI, MNDWI) and topographic (SPI, TWI, LS) indices were investigated, providing details of spatial and temporal variations in the terrestrial water cycle. The analysis permitted the hydrological characteristics of the study area to be mapped with sufficient accuracy. Water bodies, low-flowing streams, water flow direction, vegetation cover, erodible areas, locations with water accumulation, and areas with high soil moisture were identified. A major additional outcome of this research was the construction of flood-susceptibility maps introducing several hydrological parameters in a fuzzy model. The results indicated several areas inside the mining area with high flood susceptibility. These results were subsequently validated through PPC flood event reports during heavy rainfalls and events reported in the National River Basin Management plans. Using high-resolution digital elevation models and remote sensing data processing to identify hazards, like flooding, could improve land use planning and water management strategies.