A physically based model for mesoscale SuDS–an alternative to large-scale urban drainage simulations

This study presents a deterministic, lumped model to simulate mesoscale sustainable drainage systems (SuDS) based on a conceptualization of the stormwater control measures (SCMs) making up the system and their influence on the runoff process. The conceptualization mainly relies on parameters that are easily quantifiable based on the physical characteristics of the SCMs. Introducing a nonlinear reservoir model at the downstream end of the SuDS results in a fast model that can realistically describe the runoff process at low computational cost. Modelled hydrographs for the study area in Malmö, Sweden, matched data with regard to the overall shape of the hydrograph as well as the peak discharge and lag time. These output parameters are critical factors to be considered in the design of large systems consisting of mesoscale SuDS. The algebraic foundation of the developed model makes it suitable for large-scale applications (e.g., macroscale), where the simulation time is a decisive factor. In this respect, city-wide optimization studies for the most efficient location and implementation of SuDS are substantially accelerated due to fast and easy model setup. Moreover, the simplicity of the model facilitates more effective communication between all the actors engaged in the urban planning process, including political decision makers, urban planners, and urban water engineers.