Numerical Studies on Dune Breaching Due to the Hydrodynamic Impact of Storm Surges Based on a Large-Scale Research Dune

The aim of the collaborative project PADO (“Processes and implication of dune breaching at the German Baltic Sea Coast”) is the investigation of dune breaching and the resulting flooding of the hinterland based on a large-scale research dune. During the physical model test, which was located at the beach of Rostock-Warnemuende, the dune was destroyed by a storm surge in November 2018. The measured data served as basis for the set-up of a numerical coastal erosion model with XBeach. The application of the latest XBeach-X release with the default settings results in an underestimation of the mean wave height at the model entrance. Moving closer to the shore, the underestimation decreases leading to a good agreement with observed wave heights in the nearshore zone, especially after the first third of the simulation. Furthermore, the model computes dune erosion due to collision and overwash which is in line with the observation. The predicted final dune erosion is in good agreement with the post-storm measurements of the dune topography and, hence, only minor calibration is needed.