URBAN FLOOD MODELLING USING IBER-SWMM MODULE: THE CASE OF SAMPIERDARENA DISTRICT (GENOVA) Real case application

Climate change and rapid urbanization have intensified the occurrence of pluvial flooding in cities, making prediction and management increasingly complex. To address this challenge, hydrodynamic models have been developed, ranging from one-dimensional (1D) and two-dimensional (2D) approaches to integrated 1D/2D frameworks capable of simulating both sewer and surface flows. However, model reliability remains limited by the quality and resolution of input data, particularly regarding topography and integration with urban drainage systems. This study investigates these issues through a case study in the Sampierdarena district of Genoa, Italy, a densely urbanized area highly exposed to recurrent flooding triggered by short return-period rainfall events. The district includes three partially culverted streams—Fosso Bartolomeo, Fosso Promontorio, and Fosso Belvedere—and presents the combined challenges of impervious surfaces, aging drainage infrastructure, and complex topography. Flood simulations were carried out using Iber, both as a fully integrated hydrological-hydraulic model and in combination with SWMM, enabling coupled 2D/1D simulations of surface and sewer flows. Results emphasize the decisive role of spatial resolution from Digital Terrain Models (DTMs) and Digital Surface Models (DSMs). Higher-resolution inputs improve simulation accuracy but increase computational demands. These findings provide insights into the balance between data detail and model efficiency, contributing to improved urban flood risk assessment.