Boussinesq modeling of solitary wave run-up reduction by emergent vegetation on a sloping beach

To better understand the reduction of the run-up of leading tsunami waves by mangrove forests on a sloping beach, we presented a numerical model in this study, which was based on one-dimensional (1D) fully nonlinear Boussinesq equations with the effect of vegetation resistance included in terms of the drag coefficient. Solitary waves were used to model the leading tsunami waves and five models of different forest densities and tree distributions of the emergent vegetation were examined. The bottom friction and vegetation drag were calibrated based on our published laboratory experiments. Model results show that the modified Boussinesq equations could give satisfactory predictions of the solitary wave transformation over the vegetation and subsequent run-up on the slope. The drag coefficient was found to be dependent on the incident wave height. Effects of beach slope, forest density and tree distribution on the drag coefficient were also discussed based on the numerical results.