Dynamics of the Sundarbans Forested Islands in the Context of Erosion-Accretion and Sea Level Rise

Abstract

The low-lying coastal areas of Sundarbans mostly covered by mangrove forests is threatened by erosion. This study attempts to address the issues of erosion and sea level rise in the mangrove forested islands of entire Sundarbans covering India and Bangladesh. From the multi-temporal satellite imageries (LANDSAT year TM1990 and OLI 2017) the total erosion of these island system has been estimated using a combined rule-based and object-oriented classification system. Near about 325 km2 of land area has been eroded during this period over nearly three decades (1990–2017). The total Sundarbans (India and Bangladesh) has been divided into three zones – eastern, middle and western – to understand the spatial pattern and dynamics. The erosion dominates mainly in western and middle zones of the Sundarbans and decreases towards eastern zone. The rate of sea level rise has been estimated using tide gauge data and satellite altimetry data (Topex Poseidon Jason). The tide gauge data show a steady relative sea level rise in this region, which might be an important factor for the erosion. The scenario is seriously seeking bilateral management initiatives across the border to protect the pristine ecosystem and its services for futuristic benefits.