Work

Refined impact assessment of rainfall-induced urban flood in a densely populated and built-up watershed

Year: 2025

Type: article

Abstract: Study region: The Liede Watershed, a representative densely populated and built-up watershed in Guangzhou, China.Study focus: With improved disaster prevention and flood control needs, more refined spatial distribution characteristics of hazard-affected bodies in small-scale urban areas must be analyzed. To address this limitation of current methods for measuring such hazard-affected body distribution, we first employed a coupled model to simulate flooding depths and extents, to derive refined hazard information; two multi-source data types—Points of Interest (POI) and population heatmaps—were adopted, and a convenient method based on combined matrix framework was devised to assess the multifaceted impact of urban flood on assets and population, along with their combined effects.New hydrological insights for the region: The comprehensive impact results show that high-impact areas primarily consist of business districts, commercial areas, and residential areas. At 9 pm on weekends—when population vulnerability is the highest in four typical moments—the very high impact zones expand from 0.06 km² (1a) to 0.39 km² (100a) as return periods increase. The two multi-source data elucidate the intricate spatial interior distribution of assets and population, thus resolving the conundrum of fine-grained distribution within small spatial scales. The proposed method facilitates comprehensive numerical simulations and impact analyses of urban floods, thereby providing a valuable reference for convenient and accurate assessments of urban flood impacts in urbanized watersheds.

Source: Journal of Hydrology Regional Studies

DOI: 10.1016/j.ejrh.2025.102927