A Two-Dimensional Shallow-Water Model for Pluvial Flood Analysis in Urban Areas

Abstract

Urban flood simulation requires numerical models capable of representing the two-dimensional propagation of water over topographically complex surfaces under intense rainfall and localized inflows. The paper presents a two-dimensional hydraulic model based on the Saint-Venant equations (shallow-water equations). The numerical model uses a Rusanov-type flux and operates on raster-based digital elevation models (DEMs). Notably, it allows for the modeling of both spatially distributed rainfall over the domain (rain-on-grid approach) and multiple independent point sources representing urban drainage system surcharging or overflow, each associated with a specific discharge hydrograph. The results confirm the model’s reliability for urban hydraulic hazard assessments.