Assessment of Coastal Vulnerability Index and Shoreline Dynamics Along the Coast of Nagapattinam District, Tamil Nadu, India

Abstract

Coastal regions are the most dynamic and vulnerable interfaces on Earth, supporting diverse ecosystems and significant human populations, yet facing escalating threats from climate change, natural hazards, and anthropogenic activities. This study evaluated the coastal vulnerability of the Nagapattinam coast, India, using a geospatially derived Coastal Vulnerability Index (CVI) to address the increasing risks of climate change, natural hazards, and anthropogenic pressures. Six key physical parameters, including geomorphology, Land Use/Land Cover (LULC), shoreline change rate, coastal slope, bathymetry, and mean tidal range, were integrated to compute the CVI. Multi-temporal Landsat TM and OLI satellite data (1994–2024) were analysed to assess shoreline dynamics, including erosion and accretion trends. The Digital Shoreline Analysis System (DSAS) was employed to calculate the endpoint rate (EPR), Net Shoreline Movement (NSM), and Linear Regression Rate (LRR). The coastal slope and bathymetry were derived using SRTM data and Naval Hydrographic Charts, respectively. The analysis revealed pronounced spatial variability in coastal vulnerability along the Nagapattinam coast. Villages, namely Nagapattinam, Vadakkupoigainallur, Therkupoigainallur, Velankanni, Prathabaramapuram, Thiruppoondi, Vizhunthamavadi, Vellapalam, Nalavedapathi, Pushpavanam, Periyakuthagai, and Vedaranyam, were identified as highly vulnerable, along with the coastal stretches of Kodiakarai and Point Calimere, which exhibited very high vulnerability owing to persistent shoreline changes and exposure to future sea-level rise. The results highlight significant landform dynamics driven by both natural processes and human intervention. This study provides a scientific basis for informed coastal zone management and risk mitigation planning. Future research can incorporate socioeconomic indicators, high-resolution climate projections, and real-time monitoring to enhance the predictive capability of the CVI framework. Such integrated approaches will support sustainable coastal development and strengthen resilience to evolving coastal hazards.