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.

In this study, a numerical model was employed to determine the optimal location for vegetation as an environmentally friendly method of attenuating tsunami waves. The governing equations are shallow water equations solved using shock-capturing schemes with second-order accuracy model. This simulation was validated using experimental data and another numerical model for simulating the propagation of tsunami waves on a vegetated horizontal bed and vegetated sloping beach. The parameters of wave damping rate, maximum velocity, and height for the plant area at various locations and vegetation zone lengths were investigated using numerical models. By increasing the length of the plant zone, the height and velocity of the tsunami wave were reduced, and the wave damping was increased. The examination of various locations and lengths of the plant area demonstrated that the plant area’s distance from the shoreline is a significant factor in coastal protection. The results exhibit that the location of the forest area has a great impact on the control of destructive factors along the beach. As a result, this study provides some information for designing a tsunami-resistant forest area.

Dam breach due to the earthquake, Land sliding inside the dam reservoir, dam overtopping as a result of intense precipitation in a watershed are examples of dangerous risks which flood caused by any of them should be predicted by suitable hydraulic or numerical models in the framework of a risk management plan. In the present research, 2DHec-Ras model has been applied in order to flood modeling of Sattarkhan dam. This dam is in the North West of Iran, located 15 km from the west of Ahar city, in the East Azerbaijan province, Iran. The downstream part of the dam to Ahar city has been studied considering the population and infrastructures in this district according to two different scenarios of dam failure. The first scenario includes piping of flow and dam failure profile with steep side walls while the second scenario consists of inclined sidewalls in the dam breach profile and overtopping of flow as the main cause of breaching. The population centers have been selected in the downstream area of dam according to the field facts. The maximum flood depth reaches up to 9.1 m for the first scenario and 7.1 m for the second scenario at the Islamic Azad University and Tabriz-Ahar road, respectively. The results show the notable risk for some of the population centers in the downstream of the dam. Furthermore, the arrival time of flood, recession time, and maximum velocities in the targeted areas for preparing emergency action plans has been calculated.