Demarcation of coastal vulnerability line along the Indian coast

Abstract

Delineation of vulnerability line for coastal region due to dynamic coastal processes and natural coastal hazards is a complex task due to high regional variability and site specific coastal characteristics. A methodology is developed using multidate satellite data, high resolution DEM and in-situ wave and tidal observations on GIS platform to delineate the vulnerability line. Three coastal regions viz. Dahej, Bharuch district, Gujarat, Paradip, Orissa and Nellore, Andhra Pradesh coast have been considered. Changes along the shoreline are considered as net impact of dynamic coastal processes and are mapped using multidate satellite data. Vulnerability due to coastal erosion has been assessed based on rate of coastal erosion. Coastal erosion for the next 25, 50 and 100 years are modeled and demarcated. Vulnerability due to coastal flooding is assessed using predicted sea level rise and storm surge events. Maximum tidal elevations, predicted sea level rise, return interval of storm surge events and maximum wave run up were considered for estimating flood height and accordingly flooding scenarios are simulated using high resolution DEM. Vulnerability line has been demarcated by integrating the shore displacement line and flood lines using GIS. The landward extent of either of the shore displacement line or flood line i.e., whichever is towards the land is demarcated as vulnerability line.