Recent advances in developing high-resolution flood forecasting systems in Germany

This presentation aims to offer valuable insights into the state-of-the-art technologies and methodologies employed to enhance Real-time Flood Forecasting (RTFF) systems by highlighting recent progress in the development of high-resolution RTFF systems. Given the existing uncertainties associated with RTFF and the documented increasing trends in flood peaks in the western and central regions of Europe 1, continuous improvement of RTFF systems is essential for better disaster risk preparedness. Recurrent and severe flooding events have impacted Germany in recent years. The predictability of two recent flooding events, including the extensive flooding from December 2023 to January 2024 across the entire country, and the 2021 summer flood in Ahrtal 5 will be explored by introducing an experimental RTFF chain. This chain utilizes high-resolution weather forecasts from Germany's National Meteorological Service, Deutscher Wetterdienst (DWD). The chain incorporates high-resolution streamflow and water level forecasts at 1 km using the mesoscale Hydrologic Model (mHM) 2,3. Additionally, it features a fast hydrodynamic model (RIM2D) at 10 m resolution 4 with an extended component for impact forecasting tailored to the scale of individual buildings. We showcase how the newly developed RTFF system enables tailored decision-making compared to the common practices currently used by local authorities. References 1 Blschl, G., Hall, J., Viglione, A., Perdigo, R. A., Parajka, J., Merz, B., ... ivkovi, N. (2019). Changing climate both increases and decreases European river floods. Nature, 573(7772), 108-111. DOI: 10.1038/s41586-019-1495-6 2 Samaniego, L., Kumar, R., Attinger, S. (2010). Multiscale parameter regionalization of a gridbased hydrologic model at the mesoscale. Water Resources Research, 46(5). 3 Samaniego, L., Kumar, R., Thober, S., Rakovec, O., Zink, M., Wanders, N., ... Attinger, S. (2017). Toward seamless hydrologic predictions across spatial scales. Hydrology and Earth System Sciences, 21(9), 4323-4346. 4 Apel, H., Vorogushyn, S., Merz, B. (2022). Brief communication: Impact forecasting could substantially improve the emergency management of deadly floods: case study July 2021 floods in Germany. Nat. Hazards Earth Syst. Sci., 22(9), 3005-3014. doi:10.5194/nhess-22-3005-2022. 5 Najafi, H., Shrestha, PK., Rakove, O., Apel, H., Thober, S., Kumar, R., Vorogushyn, S., Merz, B., Samaniego, L. (in review). Advancing a High-Resolution Impact-based Early Warning System for Riverine Flooding. Nature communications.