Reduction of maximum tsunami run-up due to the interaction with beachfront development – application of single sinusoidal waves

Abstract. Experiments are presented that focus on the interaction of single sinusoidal long waves with beachfront development on the shore. A pump-driven methodology is applied to generate the tested waves in the wave flume. The approaching waves firstly propagate over a horizontal bottom, then climbing up a 1 in 40 beach slope. The experiments reported here are confined to the surf similarity parameter of the waves ranging from ξ =7.69–10.49. The maximum run-up of the tested waves under undisturbed conditions agrees well with analytical results of of Madsen and Schäffer (2010). Beachfront development is modelled with cubic concrete blocks (macro-roughness (MR) elements). The obstruction ratio, the number of element rows parallel to the shoreline as well as the way of arranging the MR elements influences the overall reduction of maximum run-up compared to the undisturbed run-up conditions. Staggered and aligned as well as rotated and non-rotated arrangements are tested. As a result, nomograms are finally compiled to depict the maximum run-up reduction over the surf similarity parameter. In addition, some guidance on practical application of the results to an example location is given.