An Integrated Approach for Urban Pluvial Flood Risk Assessment at Catchment Level

Abstract

With the rapid development of urbanization and global climate change, urban pluvial floods have occurred more frequently in urban areas. Despite of the increasing urban pluvial flood risk, there is still a lack of comprehensive understanding of the physical and social influencing factors on the process. To fill this knowledge gap, this paper proposes a novel approach to calculate the comprehensive urban pluvial flooding risk index (PFRI) and investigates the interplay impacts from different components at catchment level. To be more specific, PFRI is determined by two components, Exposure Index (EI) and Social Vulnerability Index (SoVI). EI is evaluated based on two indicators, the depression-based Topographic Control Index (TCI) and impervious area ratio. SoVI is measured based on a set of demographic and socio-economic indicators. Our results demonstrated the spatial heterogeneity of urban pluvial flood exposure and social vulnerability, as well as the composite flooding risk across the study area. Our catchment-based urban pluvial flooding risk assessment method can provide a comprehensive understanding of urban flooding and promote the formulation of effective flood mitigation strategies from the catchment perspective.