Physical Vulnerability of Individuals to Coastal Flood Hazards in Urban Areas

Abstract

Storm surge flooding in low-lying coastal cities is among the costliest and deadliest natural disasters. Sea-level rise due to global warming is expected to increase the intensity of coastal flooding. A quantitative understanding of flood hazards and vulnerability is necessary for flood risk assessment in the built environment. The research presented here aims to quantitatively understand the human vulnerability to storm-induced coastal flooding in the built environment and its response to flood hazards under the effects of sea-level rise. This research develops a physics-based human instability model, considering hazards from both floodwater and extreme winds during coastal flooding events. The research employs a variance-based sensitivity analysis to quantify the uncertainty of the model’s input variables on the simulated critical water speed. Results indicate that winds have a profound effect on human vulnerability, suggesting that flood risk assessment studies should account for human vulnerability to combined floodwater and wind hazards. This research further implements the developed human vulnerability model in concert with a building-scale flood model to simulate human vulnerability to flooding hazards induced by a historical hurricane in Manhattan, NY, under present-day and various future sea-level rise scenarios. The study finds that the response of flood hazards and human vulnerability to sea-level rise is non-linear. It is shown that the effects of sea-level rise on flood hazards would substantially affect the extent, intensity, and duration of human physical vulnerability to coastal flooding. Given the importance of human vulnerability in flood risk assessment, the developed vulnerability model, coupled with flood hazard forecasting systems, enables more comprehensive coastal flood risk forecasting.