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.
