Trend of Sea-level-rise in West Bengal Coast

Abstract

Coastal West Bengal, the low-lying landward extension of the continental shelf of the Bay of Bengal is one of the most vulnerable regions to climate change. Extreme climate - driven multifarious threats, including tidal gushes, deluge with seawater, permanent submergence of land, occurrence of salinity and water scarcity have taken a toll on food and environmental security of the region. The present article discusses sea-level-rise trends in the estuaries of West Bengal coast and compares it with other coastal region of India, based on estimates derived from tide-gauge data. The PSMSL (Permanent Service for Mean Sea Level) tide data have been analysed to detect the changes of sea level trend using Mann-Kendall non-parametric test and the magnitudes of such trends have been estimated using Sen's slope. The results affirmed that the rate of sea level changes for four stations, namely, Garden Reach, Diamond Harbour, Haldia and Gangra in West Bengal coast are found to be +7.48, +4.27, +3.24 and +2.06 mm yr^-1 whereas for the stations Mumbai and Cochin in west coast the rate of changes were +0.78 and +2.07 mm yr^-1 and for Chennai and Vishakhapatnam in east coast the rate of changes were +1.06 and +1.00 mm yr^-1. The rise in sea level in West Bengal coast was more during the last ten years (2005-2014) and it increased by 1.65% of long term average in the region. The information on rate of sea level would help in implementing defences against coastal flooding and salinity due to rising sea level.