Author(s): Yangwei Zhang; Lennart Steffen; Franziska Tugel And Reinhard Hinkelmann
Linked Author(s): Franziska Tuegel, Reinhard Hinkelmann, Lennart Steffen
Keywords: Urban flood modelling large underground infrastructure infiltration in urban areas hms++
Abstract: Urban flood and inundation have become a frequently seen disaster around the world. It is necessary to represent real cases as detailed as possible in a model to provide an accurate surface flow prediction. Underground infrastructure like drainage systems, transportation tunnels and subway stations are inevitable constructions in large cities, which also have strong effects on the surface runoff processes. Therefore, taking them into consideration in a model is of great significance. The shallow water model hms++ (Hydroinformatics Modeling System) incorporated the SWMM routing module for the subsurface drainage system to build a bi-directionally coupled hydrodynamic model for surface and drainage flow. In this work, it is applied to explore its capability of correctly representing a long road tunnel in the center of Berlin, Germany. Furthermore, the coupled model is used for another part of Berlin exploring urban flooding under different scenarios of rainfall, surface properties and measures. This extended abstract displays two of the cases to show exemplary results. The first case shows that the coupled model can successfully represent the tunnel and offer flow information inside the tunnel, which can be used for flood risk assessment. The second case explores the impact of infiltration on surface inundation under two intensive levels of rain events, i. e. a historical 100-year event and the strongest event of climate simulations between 1971 and 2100, respectively. Results show that the inundation depth at a selected flooding hotspot decreased more than 30 cm when taking infiltration into account for these two events. To be more specific, the peak water depth is reduced by 33% for the historical while only 18% for the strongest event. For the peak discharge, the reduction for both is similar and both surface inundation volumes decreased with infiltration. These results indicate that infiltration is necessary for urban inundation evaluation.
Year: 2025