Delineation of Decadal Changes of Shore Line and Geomorphology over West Bengal, India using Remote Sensing and GIS Techniques

Abstract:

West Bengal Coast and Indian part of Sundarbans is highly vulnerable to various natural as well as anthropogenic activities there by causing huge impact on socio-economic structure of the region. The West Bengal coast is located at latitude 21°35’ N and longitude 87° 30’, 89° 10’ E with a coastline of 210 km and very irregular in shape. High frequency of tropical cyclones cross the West Bengal coast results in storm surges which will have large impact on the shoreline changes there by making the coast more vulnerable. Hence, understanding of shore line changes as well as the geomorphological patterns of the coast is highly essential for planning, prevention of loss of life and property. In the present study, an attempt has been made to delineate these changes using remote sensing and GIS methods over the study region. For this purpose LANDSAT imagery obtained from USGS for the years 1973, 1989 and 2010 is used for identifying the decadal changes of shoreline as well as geomorphological features. The MNDW Index has been used in delineating land and water boundary over the region. Results revealed significant changes in the shore line along the West Bengal coast as the shore-line shifting of 500 meters is noticed towards the land in some locations. Some portion of Sundarbans has shown significant erosion from 1973 to 2010 of the order of 3 km. From the analysis it is seen that more coastal erosion is over West Medinipur coastal area. Nayachar Island, Sagar Island and five more small islands near the mouth of Hugly estuary are prone to this shoreline change which may be attributed to sediment discharge and wave action, along with storm surges and inundation.

Key words: Shore line, Geomorphology, Remote Sensing and GIS