Assessment of coastal exposure of climate-driven oceanic hazards along the East Coast of India using geospatial techniques

Coastal regions face increasing threats from a range of natural and anthropogenic hazards, such as sea level rise, storm surges, coastal erosion and flooding. These hazards are intensified by climate change and rapid coastal development, placing both human populations and ecosystems at significant risk. Vulnerability to coastal hazards is influenced by geographic, socio-economic and infrastructural factors, with densely inhabited areas in low elevation being particularly susceptible. In this regard, the coastal zones are exposed to composite ocean hazards, including extreme water levels, sea level rise and shoreline change rate are used to generate the coastal multi-hazard zone (CMZ). Further, the Exposure Index (EI) at the village and town levels along the east coast was calculated to fill the gap in localised risk assessment. The study highlights the coastal villages/towns exposed to different degrees along the entire east coastline of India, spanning from Tamil Nadu to West Bengal. The most vulnerable districts from each state are Nagapattinam in Tamil Nadu, Krishna in Andhra Pradesh, Jagatsinghpur in Odisha and the North 24 Parganas in West Bengal have recorded more villages/towns under very high EI that are facing frequent inundation and need immediate attention. The top five districts in terms of percentage of population exposed are Karikal, North 24 Paraganas, Nagapattinam, Jagatsingpur and Thanjavur. The study provides different scenarios by utilizing the EI at inhabited villages/towns, through mere exposure. Though most of the deltaic and riverine environments have recorded large areas under exposure, the objective classification of villages/towns in high exposure zones adopted in this study differs in results. Hence, the EI derived in this work helps policymakers to draw site-specific interventions and disaster managers to focus on preparedness and adaptive measures to mitigate risks associated with coastal hazards in order to build resilient coastal communities.