Quantitative estimation of urban flood damage from storm surges for a coastal city

The flood losses caused by storm surges are very severe in coastal cities, which highlights the importance of quantitative assessment of disaster risks. This study estimates the potential life and vehicle damage in the coastal city of Macau based on flood scenarios and storm surge probabilities. The hydrodynamic model considering surface flow and drainage system is applied to simulate floods caused by storm surges. Based on the flood results of the model and the vulnerability, a distribution map of mortality and car damage in the study area was obtained. The proportion and total loss of flood life and cars corresponding to different probabilities are calculated. We found that about 20% of the study area has a flood mortality exceeding 0.003 and cars are damaged when the exceedance probability of flood is below 0.005. When the exceedance probability of flood is less than 0.001, it may result in about 5 fatalities and car losses exceeding 13 million. This study provides a valuable reference for improving flood management and mitigation.