The influence of berms and roughness on wave overtopping at rock-armoured dikes

Average overtopping discharge is a crucial parameter for design and reinforcement of dikes. Rock armours and berms are widely used to reduce wave overtopping discharge by introducing slope roughness and energy dissipation. Since-methods for estimating the influence of a rock berm and roughness of rock armour at dikes on the average overtopping discharge still need to be developed and/or validated, this study aims to empirically develop better quantification of the reductive influence of rock armour on wave overtopping, compared to-existing procedures. That is derived based on the analysis of experimental data from physical model tests. Moreover, the influence of roughness of a rock armour applied only on part of waterside slopes is estimated by introducing location weighting coefficients. Results show that the newly derived methods for evaluating the influence of berm and roughness for rock-armoured dikes lead to significantly-better predictions of the average wave overtopping within the tested ranges compared to existing ones.