Generally applicable routines were developed which automatically transform a detailed sewer network model with long calculation times into a simplified and thus fast-running model. This model is fast enough to be used in an online model e.g. a digital twin. Such a model forms the basis for runoff simulation in a Digital Twin of the sewer network in Hanover.

Certain applications of urban drainage models require highly-performant models. Such applications include, among others, their use within Digital Twins and within real time control frameworks, in particular when model-based predictive control is envisaged. In addition, other modelling applications that involve the evaluation of long time series and/or of a multitude of scenarios also require high-performance models, such as the analysis of Blue-Green Infrastructure systems for large networks. A newly developed generic and automatic procedure allows the transformation of complex sewer simulation models into simplified ones. The resulting models are fast enough to be used as an internal model within a Digital Twin or within a model-based predictive real-time control system. Besides the implementation within a Digital Twin of the sewer system of Hannover, this automated routine has also been applied to a number of sewer systems in Europe, Asia and the Americas. A combination of detailed hydrodynamic with simplified hydrological modelling approaches within the same model allows to combine the advantages of both modelling approaches within the same model.