Multi-hazards coastal vulnerability assessment of Goa, India, using geospatial techniques

Abstract

The state of Goa in West India has a 105 km long coastline with beaches and cultural heritage sites of significant importance to tourism. The increasing incidence of tropical cyclones in the Arabian Sea in recent decades and the devastating impacts of the December 2004 tsunami in India stressed the importance of assessing the vulnerability of coastal areas to flooding and inundation, notably in view of climate change induced sea-level rising (SLR). This study aims to develop a Coastal Vulnerability Index (CVI) for the state of Goa and to use this index to examine the vulnerability of the different administrative units of the state, known as talukas. This is accomplished by using seven physical and geologic risk variables characterising the vulnerability of the coast, including historical shoreline change, rate of relative sea-level change, coastal regional elevation, coastal slope, mean tidal range, significant wave height, and geomorphology using conventional and remotely sensed data, in addition to two socio-economic parameters: population and tourist density data. Using a composite CVI based on those relative risk variables, each of the seven coastal talukas was categorised according to its vulnerability. The resulting vulnerability map depicts the talukas that are the most and least vulnerable to erosion, flooding and inundation of coastal lands, and that the inclusion of socio-economic parameters influences the overall assessment of vulnerability. This study provides information aimed at increasing awareness amongst decision-makers to deal with disaster mitigation and coastal zone management, and is a first step towards prioritising areas for climate change adaptation in view of the projected SLR and increased storminess.