Assessment of shoreline changes of Alibag coast (Maharashtra, India) using remote sensing and GIS

Abstract

The analytical and data integration capability of GIS and the spatial, temporal, spectral and radiometric resolutions of remote sensing help to gain insights into the biophysical systems. These technologies are widely used in geomorphological studies. Remote sensing and GIS technologies were used to study the shoreline changes of Alibag in Raigad district of Maharashtra, India, which lies between 18° 30’N and 18° 45’ N latitude, and 72° 45’ E and 73° 00’E longitude. IRS-1D LISS III satellite image (2005) and Survey of India (SOI) toposheet (1971) with the map ID 47 B/14 both on the scale 1: 50,000 were used in the change detection study. GIS software GRAM++ and ArcView 3.2 were used for the analysis. Total areas of erosion and accretion along the Alibag coast were found to be 3.81 km2 and 6.5 km2 respectively during the last 34 years (1971 to 2005) Ground-truthing validated the findings of the study. Anthropogenic activities like land reclamation, increased human settlements, industrial development, recreational and tourism activities were responsible for the accretion in these areas. Erosion was mainly due to natural forces especially in the eastern side of Korlai where the Kundalika River is flowing. Anthropogenic activities like dredging and deforestation were the causes of erosion in other places of the study area. Shoreline changes resulted in displacement of coastal population, loss of property, salinisation of land and water, as well as decrease in fish landings. The study amply demonstrated the utility of remote sensing and GIS technologies in monitoring and detection of coastal features.