Experimental study on the use of artificial meadows that mimic wave-vegetation interactions for coastal protection

Abstract

A detailed experimental study was conducted on five artificial meadows made of structures that mimic wave-vegetation interactions. The meadows were of different lengths and leaf thicknesses under regular and random waves, such that the leaf thickness changed as the meadow length increased. Different wave heights, periods, and tidal conditions were examined. The results for regular and random waves were consistent. The meadow length had a stronger influence (30%–50%) on wave transmission than leaf thickness (5%–10%). A lower wave transmission was observed at higher wave energies due to enhanced wave-vegetation interaction, higher wave reflection, and effective energy dissipation. Compared with submerged conditions or when the top of the meadow was at still-water level, a lower wave transmission and higher wave reflection and energy dissipation were noted when the leaves emerged in the air. The longest meadow in the emerged condition reduced the wave height by more than 50% at mid meadow. Furthermore, a wave transmission coefficient of 0.3 was achieved by this model, which is desirable for the design of this wave barrier type. The model with the best overall hydrodynamic performance can be used alone or combined with existing natural vegetation for coastal protection.