Numerical Simulation of Run-Up and Land Inundation on the Vegetated Sloping Beach

Abstract

Vegetated areas on the beach can reduce tsunami heights and reduce the loss of life and property damage in coasts. Thick trunks and tangled branches attenuate tsunami waves. In this study, a numerical model is developed based on the finite volume method for simulating tsunami flooding. This model is used to simulate the solitary wave run-up propagation on sloping beaches with and without vegetation. The shallow water equations are used, also the effect of drag force due to vegetation is applied in the momentum equation. The HLLC approximate Riemann solver is selected, and the model is developed to second-order accuracy using the Weighted Average Flux method. After verification of the present model, the model is applied for simulation of solitary wave on a sloping beach. The present model results are compared to the available experimental data and another numerical model. The present numerical results reveal that as forest belt’s width increases, the height, velocity, and force of the tsunami waves decrease. Therefore, to further reduce the tsunami energy, a wider belt is recommended. Also, the effect of different tsunami wave heights on the rate of wave reduction has been investigated. In some areas, the presence of high tsunami waves causes to submerge the vegetation. Consequently, the drag force and the damping rate of the wave decrease. Therefore, the height of the forest zone and the height of the tsunami waves are important parameters.