Integrated Coastal Change and Flood Susceptibility Assessment of the Mahabalipuram–Puducherry Coast Using GIS and Remote Sensing

Coastal regions are the most dynamic and environmentally sensitive areas and are highly vulnerable to hazards such as shoreline erosion and coastal flooding. Monitoring shoreline changes is important for effective coastal management and disaster risk reduction. In this study, an integrated assessment of shoreline change and coastal flood susceptibility was carried out for the Mahabalipuram–Puducherry coast using GIS and Remote Sensing techniques. Multi-temporal satellite images from the years 1990, 2010, and 2025 were used to extract shoreline positions. Shoreline change analyzed through transect-based measurements and Net Shoreline Movement (NSM) and End Point Rate (EPR) were calculated to identify erosion and accretion zones. The EPR analysis indicated that 39.08% of the analyzed shoreline change records experienced erosion, while 10.34% remained stable and 50.58% showed accretion. These results highlight the dynamic nature of the Mahabalipuram–Puducherry coastline. For flood susceptibility mapping, a 30 m SRTM Digital Elevation Model (DEM) was used to derive elevation and slope, and a distance-to-coast layer was generated through proximity analysis. These factors were integrated using a weighted overlay to produce a coastal flood susceptibility map. The resulting flood susceptibility map shows the classification of varying levels of flood risk, which ranges from low to very high susceptibility. This integrated analysis provides an understanding of long-term changes occurring along the coastline and the flood-prone areas. The results demonstrate how GIS and Remote Sensing can support coastal monitoring, helping planners and decision-makers to develop strategies for coastal protection and sustainable management.