Irregular Wave Seepage and Overtopping of Permeable Slopes

Abstract

Experiments were conducted in a wave flume to investigate wave seepage and overtopping of permeable stone slopes with wide crests. The numerical model based on the time-averaged continuity, momentum, and energy equations is extended to include the landward water flux due to wave seepage and overtopping. The measured wave runup distributions are fitted to the Weibull distribution whose shape parameter increases with the increase of the wave overtopping probability. The wave overtopping rate normalized by the wave-induced water flux at the still water shoreline is shown to depend on the wave overtopping probability and the horizontal number of stones above the maximum wave setup. A simple formula for the seepage rate is proposed by analyzing the seepage flow driven by the wave setup on the seaward slope. The extended numerical model is shown to be in agreement with the measurements of the free surface elevation, cross-shore velocity, wave runup, and seepage and overtopping rates but will need to be evaluated using more extensive data sets.