Assessing coastal vulnerability to environmental hazards of Indian Sundarban delta using multi-criteria decision-making approaches

The low lying Indian Sundarban delta (ISD) is highly susceptible to multiple coastal hazards and disasters. The increasing frequency and intensity of natural hazards have been influenced by global climate change and devised an additional burden for coastal dwellers to sustain their livelihood in such a hostile environment. Therefore, the identification of priority blocks in terms of the degree of vulnerability is very important for resilience building and disaster preparedness. In this context, the coastal vulnerability index (CVI) of ISD was assessed based on multi-criteria decision-making approaches (MCDA). Various vulnerability sub-indices like exposure, sensitivity and adaptation capacity index were calculated based on 22 indicators primarily considering physical, climatic and socio-economic variables. The CVI was constructed using both equal and unequal weightage methods. All variables were given equal importance in the simple average method whereas unequal weightage was assigned to the indicators depending on their relative importance with vulnerability applying the methods of analytical hierarchy process (AHP) and principal component analysis (PCA). Thereafter, the composite vulnerability ranking (CVR) was statistically quantified using vulnerability index derived by aforesaid three methods. In this study, the vulnerability index was calculated for different administrative units which are considered here as C.D. Blocks. The analysis revealed that the southern coastal C.D. Blocks of the ISD which have direct coastline with the Bay of Bengal are most vulnerable due to the potential impact of coastal hazards whereas northern C.D. Blocks are comparatively less vulnerable because of less exposure to coastal hazards, moderate sensitivity and high resilience to resist the adverse impact of hazards. This study will help to understand the comparative similarity and suitability of these three methods for assessing coastal vulnerability and this information could be used as a recommendation for other regions also.