Vulnerability of Individuals to Compound Hazards due to Floodwater and Winds in the Coastal Built Environment

Abstract:

Flood risk assessment requires a quantitative understanding of hazards and vulnerability. In the coastal built environment, the vulnerability of humans to floodwater and wind hazards is an integral component of storm-induced flood risks. This study develops a physics-based model to quantify the physical vulnerability of individuals, adults, and children, to compound hazards of floodwater depth and speed and winds during storm-induced coastal flood events. The model accounts for the physical instability of individuals due to slipping and toppling. The governing equations consider the balance between the driving and resisting forces and moments applied to an individual who is concurrently exposed to floodwater and winds. The model determines critical values for the water depth and speed and wind velocities to identify flooded areas that become hazardous (in terms of intensity of flood/wind hazards), failure (due to physical instability), and drowning zones. We first calibrate the model using existing measurements in the literature and then implement it to reveal the vulnerability of New York residents to coastal flooding during Hurricane Sandy. We will present and discuss the model results, including the spatial and temporal variations in the vulnerability of individuals in Manhattan, vulnerability of adults and children to failure and drowning, and effects of winds on the physical stability of individuals exposed to flooding.