Sensitivity Analysis-Aided Calibration of Urban Drainage Modeling

This paper presents a novel methodology for the event-based calibration of urban drainage models based on conceptual simulation of external sub-catchments and physical representation of underground channels. Following the setup of the numerical model of an urban drainage system and the definition of the list of parameters, the methodology proposed is based on two steps, namely the application of sensitivity analysis for the identification of influent parameters and the calibration of the model on each event considering the reduced set of influent parameters by means of an optimizer. The methodology is applied to the Cascina Scala urban catchment in Pavia, northern Italy, for which a rainfall/runoff dataset is available for 14 events. In the applications, the urban drainage system is constructed in the EPA-SWMM environment, and a genetic algorithm is used for calibration. The results prove that the model parameterized with the innovative methodology features a very good fit to experimental data concerning hydrographs at the exit of the catchment while offering significant computational advantages compared with the usual calibration approach.