Integrating hydrodynamic flood scenarios and shophouse-specific depth-damage functions for risk assessment in Ho Chi Minh City, Vietnam

This study assesses flood risk in Ho Chi Minh City by integrating hydrodynamic flood modelling with shophouse-specific depth–damage functions. Fluvial, pluvial, and coastal flood scenarios were simulated for six return periods, and construction losses for irregular and peri-urban shophouses were estimated and then integrated into citywide Expected Annual Damage (EAD). The results show that flood type and urban structure produce strongly differentiated patterns of exposure and damage. Pluvial flooding exposes the greatest number of buildings, whereas fluvial flooding produces deeper but more spatially restricted inundation. Pluvial and coastal flooding generate similarly high estimated EAD values of €3.53 billion and €3.50 billion, respectively, while fluvial flooding generates a lower EAD of €2.56 billion. At equivalent inundation depths, irregular shophouses experience consistently higher relative damage than peri-urban shophouses. Irregular shophouses consequently account for the largest proportion of EAD across all three flood types, while peri-urban shophouses exhibit particularly high exposure to coastal flooding due to their concentration in low-lying urban expansion zones. By linking flood-generating processes with locally specific urban typologies, the study demonstrates the value of morphology-sensitive flood-risk assessment and supports differentiated water-management, building-upgrading, and spatial-planning interventions in Ho Chi Minh City.