Coastal vulnerability assessment of the western coastal zone of Bangladesh using a coupled surge-wave-hydrodynamic model

Abstract

Coastal regions of Bangladesh face increasingly complex environmental risks from tropical cyclones, yet comprehensive vulnerability assessments remain limited. This study introduces an innovative approach to coastal vulnerability assessment for the western coastal zone of Bangladesh by integrating advanced geospatial techniques with a surge-wave-hydrodynamic model using Delft3D. By analyzing multiple critical parameters including coastal slope, elevation, sea level rise, tide range, cyclone track proximity, coastline characteristics, and land use/land cover, the study develops a Coastal Vulnerability Index considering the impact of super cyclone Amphan. The methodology synthesizes physical indices through evaluation of spatially distributed vulnerability parameters, reveals that almost 5 % of the studied coastal area can be classified as very highly vulnerable and 85 % area as highly vulnerable. Specific findings highlight extreme risks in districts like Bhola, where around 95 % of the area demonstrates potential of high coastal hazard. This analysis exposes critical limitations of traditional coastal defense mechanisms, as evidenced by 93 complete embankment failures during cyclone Amphan and extensive flooding across multiple districts. By providing a comprehensive data-driven environmental risk assessment, the study offers crucial insights for policymakers, planners, and disaster management professionals, presenting a strategic framework for developing targeted adaptation and mitigation strategies in increasingly dynamic coastal environments.