Development of an innovative approach for modelling urban surface flow during stormwater events

Abstract

The paper presents a methodology for the simulation of surface flows on urban streets during stormwater events. In a novel way with respect to past research, the sewer capacity is dynamically evaluated based on simulations to account for its variability on time during the flood event. Specifically, the methodology is based on the use of a 1D model of the sewer network and of a 1D model of the urban surface network. First, the sewer network model is used to calculate actual sewer capacity during the flood. Such results are then used to obtain a “reduced” hyetograph, which is adopted as input for the simulation of the surface network model. The methodology was applied to an urban catchment in southern Italy affected by problems of pluvial flooding. Field data - comprising direct measurements and indirect estimations (from video-clips) of flows in streets - were used for calibration and validation of the methodology. The outcomes demonstrated good agreement between simulated and observed data, indicating the reliability of the methodology for urban surface flow modelling.