Numerical investigation of solitary wave run-up attenuation by patchy vegetation

Coastal vegetation is capable of decreasing wave run-up. However, because of regrowth, decay or man-made damage, coastal vegetation is always distributed in patches, and its internal distribution is often non-uniform. This study investigates the effects of patchy vegetation on solitary wave run-up by using a numerical simulation. A numerical model based on fully nonlinear Boussinesq equations is established to simulate the wave propagation on a slope with patchy vegetation. By using the model, the process of solitary wave run-up attenuation due to patchy vegetation is numerically analysed. The numerical results reveal that patchy vegetation can considerably attenuate the wave run-up in an effective manner. In addition, high-density patched vegetation can attenuate the solitary wave run-up more effectively than low-density patched vegetation can. For the same density, patchy vegetation with a uniform distribution has a better attenuation effect on wave run-up compared to that of patchy vegetation with a non-uniform distribution.