Pragmatic Modelling of Large-Scale Urban Pluvial Flooding

Urban pluvial flooding poses increasing challenges due to climate change and rapid urbanization. The limited availability of information on subsurface drainage infrastructure and of validation data frequently constrain large-scale flood modelling. This study applies a pragmatic modelling framework, using a two-dimensional hydrodynamic model (HEC-RAS 6.7) within the Rain-on-Grid approach to simulate rainfall-induced flooding in Naples, Italy. The adopted method simplifies subsurface drainage processes while enabling a scalable application across large urban areas. The results identify flood-prone areas within the city and provide insights into pluvial flood modelling in data-scarce urban contexts. Preliminary validation is performed using flood photographs and videos collected from social media.