Assessing urban pluvial flood resilience based on a novel grid-based quantification method that considers human risk perceptions

The growing worldwide threat of urban flooding has stimulated research on flood resilience so that more targeted measures can be implemented in vulnerable areas to mitigate flood losses. During flood events, people generally show different risk perceptions for different inundation areas according to their population density, economic degree, and service function. In this study, the risk perception was quantified into weights and integrated into the resilience calculation to identify areas vulnerable to floods and posing a danger to human life and property. An area in Zhuhai, China, was selected as the research region. With the proposed novel method, the grid-based flood resilience under different rainfall scenarios and different time periods of the day (human work and rest hours) was researched. Moreover, the resilience of different land uses and the impacts of two critical parameters in the resilience equations were also studied. The results indicated that the risk perception related to a given land-use generally changed according to different periods of the day. The overall resilience of the research region was lower when more severe rainstorm occurred in a given time period. The resilience in the work hours was higher than that in the rest hours during the same rainstorm event, indicating that the living/working state of people affected the flood resilience in urban areas. Analyses of the two parameters provided plausibility verification for the parameters and indicated that a slight increase in the height of building doorsills substantially decreased the areas with low and very low resilience. And this decrease effect was more pronounced in the rest hours than the work hours. Results of this study provide an in-depth understanding of urban flood resilience and targeted guidance for engineering construction and flood management.