Coastal Erosion Study of Ponnani Region Using Multspectral Images

Abstract

A study of coastal erosion along the Ponnani coast using multispectral imageries and GIS was undertaken to assess the temporal changes in coastal erosion, its extent, magnitude and trends in the region under study. The study also aimed to evaluate the impact of the existing coastal erosion control structures with a view to assess its efficacy and to identify priority areas for coastal erosion prevention along the study area. The study utilized medium resolution LANDSAT imageries for the mapping and monitoring of the coastline erosion. The digital image processing software used for calculating the erosion rate was TNTmips 2014 professional version (Map and Image Processing System - MIPS) by MicroImages, Inc. The study revealed the usability of multispectral satellite imageries like that obtained from LANDSAT, IRS etc. satellites in assessing the temporal changes along the coastline by the combined application of remote sensing and GIS techniques. Both long-term and short-term erosion assessment showed that many places along the Ponnani shoreline are under severe erosion. Short-term erosion assessment revealed that many places were having coastal erosion rates more than -4 m/year. The impact of these shoreline protection structures and coastal processes on erosion process was also taken in to account in this study. The study revealed that Ponnani is an actively eroding coast with fluctuating erosion rates. The erosion rates were found to be high with a rate more than -4 m/year for about 35 km of the coastline considered. The areas with accelerated erosion along the coast of Ponnani need sustainable management and protective measures. The coastal erosion study using remote sensing and GIS techniques provided realistic information about the erosion process along Ponnani area and this method can be successfully used for mapping and monitoring coastal changes.