Vulnerability Assessment of Bangladesh Coastline Using Gornitz Method

Abstract

The coastal area of Bangladesh is frequently threatened by storm surges, coastal floods, shoreline erosion, and sea level rise etc. This study analyzed the coastal vulnerability using the widely adopted Gornitz method considering coastal characteristics and coastal forcing parameters of the Bangladesh coastline. Six parameters namely: Sea level rise, cyclone track density, significant wave height (SWH), rate of shoreline change, mean tidal range and coastal slope were analyzed from historical records. The quantification of those parameters was carried out using remotely sensed and model derived data. A 2-km strip along the shoreline was considered for representation of the coastline in Arc-GIS v10.3 environment. The parameters were ranked in a vulnerability scale 0–1 and classified in five categories i.e., very low, low, medium, high, and very high. Chittagong coast was found to be very high in vulnerability due to high tide range and cyclonic activity. Cox’s Bazar coast showed high vulnerability due to SWH. The Feni estuary and Passur river entrance was under moderate vulnerability class due to shore line erosion. The rate of SLR was 8–35 mm/year along the coastline. The study revealed that about 55 km of shoreline is very highly vulnerable and 90 km is highly vulnerable. The developed vulnerability map will certainly help in the coastal management of Bangladesh under climatic risk.