Flood risk assessment of loss of life for a coastal city under the compound effect of storm surge and rainfall

Abstract

Many coastal cities face the risk of compound floods induced by multiple factors such as storm surge and rainfall. Flood risk assessment helps mitigate and manage flood disasters in coastal cities. In current literature, study about compound flood risk assessment of loss of life is limited. This study assesses the risk of loss of life in compound floods under storm surge ad rainfall in the Macao Peninsula which is a coastal city. The joint probability for storm surge and rainfall occurrence was analyzed by copula function. The coupled hydrodynamic model of drainage and overland flow was established to simulate the compound flooding process. The risk of loss of life is quantitatively assessed based on the mortality function for flood scenarios with different probabilities. The western coastal area of Macao Peninsula is the most vulnerable area to flooding with higher mortality. Although the most area of Macao Peninsula has low mortality, there is still a serious loss of life in extreme floods due to high population density. This study provides guidance for quantitative compound flood risk assessment and risk management of loss of life in coastal cities.