Modelling wave overtopping for flood defense reliability

Failure of dike covers due to wave overtopping erosion may initiate dike breach. Surface transitions in the dike cover, such as cure points, height difference, roughness difference and objects are often weak spots, but the effects of such transitions on the wave overtopping discharge and associated location and evolution of dike cover erosion are highly uncertain. Dike cover erosion is dominated by the turbulence-dominated shear stress at the jet front. Therefore, a detailed numerical Finite Element model was developed. In this paper the preliminary results of the model of Aguilar-Lopez (2016) and Bomers et al. (2018) are briefly presented. At the University of Twente, two PhD students recently started on the challenge of quantifying the effect of transitions in grass covered dikes on dike erosion. In this paper, we present their research plans.