Chapter 23 - Habitat Risk Assessment Along Coastal Tamil Nadu, India—An Integrated Methodology for Mitigating Coastal Hazards

Abstract

The coastal region provides sustenance to life on land and in the sea. Though in transience, the present coastal configuration, landforms, and ecosystems are largely the remnants of the Quaternary period. These landforms and ecosystems also preserve the vestiges of multitudes of intrinsic and extrinsic processes that continue to shape them through recurrent oceanographic, climatic, biotic, and lithogenic agents and events. More recently, since the advent of the Anthropocene period, human endeavors have detrimentally impacted these natural systems, impacting the coastal infrastructure, and the lives and habitations of humans. This chapter assesses the coastal vulnerability to natural and anthropogenic ecosystems and infrastructure based on a set of critical parameters in order to develop a mitigation plan, should there be any exigency. The study described herein evaluates the coast with a Coastal Vulnerability Index (CVI) to find the risk zone for mitigation in the habitation area. The three major indicators (physical, socio-economic, and environment and climate) and their 13 subcriteria (Physical: elevation, slope, geomorphic units, shoreline proximity, storm affected areas; Socio-economic: population density, household density, road proximity, literacy rate, built-up near to shoreline; Environment and climate: land use/land cover, normalized difference vegetative index, and rainfall) were considered to assess the vulnerability, for which weights and ranks were assigned through the Analytical Hierarchal Process (AHP) and GIS techniques. The major indicators were separately analyzed to generate a Physical Vulnerability Index (PVI), Socio-economic Vulnerability Index (SVI), and Environment and Climate Vulnerability Index (ECVI). These three layers of vulnerability indices were overlaid to prepare the CVI with five classes, namely, Very High Vulnerable (VHV), High Vulnerable (HV), Moderate Vulnerable (MV), Low Vulnerable (LV), and Very Low Vulnerable (VLV). Then, the CVI classes were designated into Coastal Vulnerable Zones (CVZ), I, II, and III, in which the risks involved were ascertained, and accordingly, mitigation strategies were framed for disaster risk reduction.