Hydrodynamic modelling of wave overtopping flow over grass-covered dikes

High waves during storms can overtop the dike and erode the grass cover resulting in dike failure. Erosion of the cover occurs when the hydraulic load of the overtopping wave exceeds the dike cover strength. High hydraulic loads are caused by three processes: 1) turbulence, 2) high wave front velocities and 3) wave impact at geometric changes in the cross-dike profile. Existing models are only capable of describing the hydraulic load caused by one of these processes. However, a model that accounts for all three processes is required to understand how the hydraulic load varies along the dike profile (Van Bergeijk et al., 2019).