Extreme weather events, which now occur regularly as a result of climate change, pose major challenges for cities and municipalities. At Dresden, the Institute of Hydraulic Engineering and Technical Hydromechanics (IWD) is developing an "Urban Digital Heavy Rain Twin" for the Saxon state capital. In future, users will be able to use the app to simulate heavy rainfall events, obtain information on hazard situations and prepare protective measures on this basis. The prototype based on free and open software is now available.
As part of the model project Smart City Dresden , researchers at IWD have been working since May 2024 on the technological and methodological creation of the so-called heavy rain twin: a virtual model of the city in which geographical data (the topography Dresdens) and urban information (such as street and building types) are brought together. After integrating specialist information from hydrology and hydrodynamics, runoff simulations can be carried out in the digital twin
"The aim of the project is to create a powerful system that can be used both as an early warning system for heavy rainfall events and as a planning tool for adapting to climate change," explains developer Lars Backhaus.
he prototype offers fully automated generation of 2D simulation models, which can be supplemented by precipitation forecasts from the German Weather Service. 3D map model of parts of Dresdenin which a flood is simulated. The simulation results provide detailed information on water depths and flow velocities in flooded areas and can be intersected with urban infrastructure elements such as roads and buildings in order to precisely analyze potential hazards.
Basic map and area data can be visualized and accessed via a 3D web app available for desktop and mobile devices. Users can start heavy rain simulations in manually selected urban areas and track the results in real time. The flood risk can be assessed for the entire urban area down to individual buildings in order to ultimately calculate the potential impact and damage. This can support the responsible authorities and private individuals in making flood prevention decisions.
According to Backhaus, a special capability of the system is that the simulation models can be generated quickly and easily on the basis of the municipal and state-wide database linked in the Urban Digital Twin. Image of a 3D map model Dresdens. In the center of the image is a vertically aligned slider. On the left is a simulated century flood, on the right an extreme heavy rainfall event. In this way, both classic 2D hydrodynamic-numerical simulations for urban areas and derived 3D simulations of structures such as bridges can be created. This allows the city to obtain precise data on the risk of flooding and thus react more quickly in the event of a disaster.
The platform is to be made publicly accessible in the second quarter of 2025. The complete development of the Urban Digital Heavy Rain Twin is planned for the end of 2026. Further development beyond this is planned.
Background
The project management of the state capital (Eigenbetrieb IT-Dienstleistungen) is working together with the TU Dresden in several areas in the pilot project Smart City Dresden . The WISSENSARCHITEKTUR - Laboratory of Knowledge Architecture is responsible for scientific management. A business informatics research team is investigating the value generation of the urban open data portal. The "Environmental monitoring/digital heavy rain twin" measure is being developed under the direction of the environmental office of the state capital Dresden (Dr. Katja Maerker) and continues the BMU-funded project WAWUR (Wild run-off water in urban areas).