GIS based assessment of storm surge inundation susceptibility in the selected coastal districts of Bangladesh using AHP, Fuzzy AHP and Fuzzy Logic

Abstract

Coastal districts of Bangladesh are highly vulnerable to storm-induced surges, posing significant risks to lives, livelihood and critical ecosystems. This study evaluates storm surge inundation susceptibility in two geomorphologically distinct districts, like mangrove-sheltered Satkhira and openly exposed Patuakhali, by using geospatial techniques. Ten physical, ecological, and meteorological parameters were normalized and incorporated into Analytical Hierarchy Process (AHP), Fuzzy Logic (FL), and Fuzzy Analytical Hierarchy Process (FAHP) models. Susceptibility maps for all three methods were generated through overlay analysis. Results show clear spatial differentiation between the districts. Under AHP, very high susceptibility zones covered 18.26% of Patuakhali and 9.93% of Satkhira, while high susceptibility accounted for 26.58% and 22.07%, respectively. FAHP produced similar patterns, with very high susceptibility zones occupying 17.91% of Patuakhali and 6.29% of Satkhira. The Fuzzy Logic model yielded more conservative estimates, with very high susceptibility zones covering 8.58% of Patuakhali and 3.76% of Satkhira. Moderate susceptibility was widespread across both districts (22–33%). Model validation using ROC analysis indicated strong predictive performance. In Satkhira, accuracy followed Fuzzy Logic (AUC = 0.904) > AHP (0.871) > FAHP (0.829), while in Patuakhali, AHP (0.896) and FAHP (0.936) showed high reliability. Across all models, southern Patuakhali consistently exhibited the highest susceptibility. In contrast, Satkhira showed lower to moderate susceptibility in northern and southern zones, although elevated-risk zones persist in central areas. The findings highlight hydrological connectivity, vegetation cover, and meteorological variables as key determinants, providing a robust basis for coastal planning and climate-resilient disaster management in southwestern Bangladesh.