Wave attenuation properties of eelgrass meadows estimated from dynamically-scaled experiments

Given the global warming, sea level rise and its associated hazards to coastal zones (i.e., erosion) are inevitable. Being more sustainable, Nature-based coastal protections are being promoted and applied more than ever. Underwater vegetation in shallow waters such as eelgrass, as a nature-based mean, is capable of reducing the wave height coming to the shore yet they have not been thoroughly studied and addressed in the literature. This study assesses the eelgrass wave attenuation ability and the associated properties through a set of dynamically scaled simulation experiments on wave-vegetation interaction. The experiments were conducted in the wave flume equipped with a piston wavemaker and resistant wave gauges to record wave heights. A wide range of wave conditions and water levels was taken into account for different vegetation densities aiming to obtain a more robust result. Eventually, a wave dissipation coefficient was estimated for the eelgrass meadows from the experimental data and was compared with the predicting analytical model proposed in the literature. A relatively reasonable agreement was observed between the experimental result and the predicting model which given the tested wide range of wave and water levels proves the accountability of the predicting model.