Nonlinear wave propagation in a vegetated sandbar-lagoon system

Abstract

The sandbar-lagoon system presents a rich variety of values. At the same time, the degradation of ecosystems and coastal erosion caused by human activities and climate change are even more severe. A series of ecological conservation and restoration projects focused on vegetation rehabilitation have been implemented. However, there is insufficient scientific evidence to guide coastal engineering in the presence of vegetation. In this paper, ten tests were presented to experimentally investigate nonlinear wave propagation in a vegetated sandbar-lagoon system. The following conclusions can be obtained. In the absence of vegetation, the low-frequency wave energy proportion gradually increases with the rise of incident wave height. Double-peaked and even multi-peaked spectra are notable throughout the propagation in tests with larger incident wave heights. Wave height decay and wave energy dissipation due to vegetation effects increase as the incident wave height increases. The dependence of the wave energy dissipation induced by vegetation on the incident wave energy (the square of wave height) presents a linear relationship. Vegetation plays an important and complex role in both sea-swell wave and infragravity wave attenuation.