Coastal vulnerability assessment to multi hazards in the exposed coast of Southeastern Coastal Region of Bangladesh

Abstract

Bangladesh is a maritime nation situated on the northern side of the Bay of Bengal (BoB), blessed with substantial natural resources and opportunities. However, natural disasters and climate-induced hazards are threatening these opportunities as well as destroying the recourses. Coastal vulnerability assessment aids in the prevention of loss of life and resource devastation since it provides forewarning of impending calamitous consequences and facilitates taking mitigative measures. The study has endeavored to make a composite coastal vulnerability index (CVI) for the exposed coast of the southeastern coastal region of Bangladesh, combining physical and social vulnerability indexes using several physical and social parameters. The CVI was developed by using nine physical parameters, namely (a) Coastal Elevation, (b) Coastal Slope, (c) Annual Average Rainfall, (d) Storm Surge Height, (e) Soil Salinity, (f) Average Wind Speed, (g) Rate of SLR, (h) Soil Permeability, (i) Mean Tidal Range and six social parameters namely (a) Literacy rate, (b) Household Structure, (c) Land Use Land Cover (LULC), (d) Population Density (e) Number of Disabled People and (f) Number of Population (Age: <5 & >65). With the aid of field and secondary data, thematic layers of each physical and social parameter were prepared by defining five distinct vulnerability classes (i.e., very high, high, moderate, low, and very low) and assigning vulnerability ranks. The final CVI was estimated using geospatial techniques such as GIS and remote sensing, coupled with Physical Vulnerability Index (PVI) and Social Vulnerability Index (SVI), and relevant values were categorized into five distinct groups as before. The findings show that 25.9% of the exposed coast in the southeast coastal region, which comprises Banshkhali, Chakaria, Maheshkhali, and Cox's Bazar Sadar is high to very high vulnerable to multiple hazards. Comparatively, 28.29% have been classified as moderately vulnerable, and the remaining 45.8% in the areas of Hathazari, Mirsharai, Sitakunda, Sandwip, and Chittagong City (Kotwali), Kutubdia show that they are very low to low vulnerable to such multi-hazards. Based on this vulnerability assessment result, sustainable coastal management policy-making and development planning can be taken to mitigate the risk and loss of the southeastern coastal region due to climatic hazards and natural disasters such as floods and storm surges. The outcome information will also help to make an Integrated Coastal Zone Management (ICZM) plan for the proper and sustainable utilization of the coastal resources. Additionally, it will assist as ground information to establish a framework for prioritizing community resilience-building initiatives or developing appropriate adaptation strategies to lower catastrophe risk.