Quantitative study on shoreline changes and Erosion Hazard assessment: case study in Muriganga–Saptamukhi interfluve, Sundarban, India

Abstract

Quantitative techniques, statistical methods and mathematical rules make the geospatial analysis more systematic, accurate and precise. In order to measure the intensity of the ongoing processes on the earth surface, evaluate the spatio—temporal changes in geographical attributes, highlight the principal factors for any geographic events and to identify the future possibilities, quantitative techniques are for most dependable. In the present article sequential changes of the shoreline, spatio—temporal extent of erosion and depositional processes of Sundarban region, West Bengal, India, have been measured following the selected quantitative techniques. The Sundarban is one of the most dynamic geomorphic units in the earth surface, situated in the northern apex of Bay of Bengal. The region has formed, sculptured and modified due to continuous sedimentation of the Ganga and the Brahmaputra systems, intense tidal hydro dynamic behavior, climatic disturbances and anthropogenic activities. In the last two century most of the parts of the active Sundarban delta has being reclaimed and occupied with dense rural settlements, most of the peoples are engaged in agriculture based rural economy, hence substantial erosion and successive regressive changes in the area have an unconstructive impact on the dwelling communities. In order to examine the net shoreline changes, average rate of end point changes and extent of erosion and depositional processes Survey of India toposheets of 1920, 1921, 1922, 1923, US Army toposheets of 1955, Survey of India toposheets of 1967, 1968, 1969 and IRS P6 LISS IV satellite images of 2014 have been used. Finally erosion hazard zones have been identified will help of net area changes of the each geomorphic units to access the spatial variation of erosion hazard intensity. Quantitative model has been prepared on the basis of multi temporal data of Muriganga–Saptamukhi interfluve area of western Sundarban which can be applied to the other parts of Sundarban region.