Integrated Environmental Impact Assessment of the Sasa Tailing Dam Failure using Remote Sensing Techniques

Failures of tailings dams represent a critical environmental hazard, releasing mining by-products that cause long-term damage to nearby ecosystems. This research presents a detailed analysis using remote sensing techniques of the 2003 Sasa tailing dam disaster in North Macedonia. By utilising Landsat 5 imagery and Google Earth Engine (GEE), multiple spectral indices — including the Normalised Difference Vegetation Index (NDVI), Normalised Difference Moisture Index (NDMI), Normalised Difference Water Index (NDWI), Modified NDWI (MNDWI), and a turbidity proxy — were integrated to examine the immediate and spatial impacts on vegetation health, soil moisture, water presence, and sediment levels. The findings indicated significant ecological fluctuations along the river path, including vegetation stress, changes in soil moisture, water pooling, and turbidity. These effects displayed spatial gradients, diminishing further from the contamination pathway and forming distinct zones of influence. Certain intermediate areas showed anomalous disturbances, where sediment and hydrological changes impeded vegetation recovery. Pixel-level, buffer-based, and zone-based analyses — combined with Z-scores and correlation studies — revealed a complex post-disaster landscape. Weak correlation with topographic features suggested that localised conditions, rather than large-scale gradients, governed short-term ecological recovery. The study provides a framework for integrated, multi-index and multiscale environmental impact assessment, contributing to improved remediation strategies, disaster response planning, and sustainable management of post-mining landscapes.