A Dynamic Wave Damping Model for Flexible Marsh Plants

Salt marshes provide protection for coasts and coastal communities by dissipating wave energy. The dissipation of wave energy depends on the geometric (leaf and stem dimensions) and bio-mechanic (material rigidity) properties of the marsh plants. This study combined measurements of drag on individual plants and wave attenuation over a meadow of plants to build a dynamic wave-damping model that includes the impact of plant reconfiguration and sheltering between plant elements. The wave-induced drag model was validated using both live and model plants. The model plants were designed to have geometric and dynamic similarity to real plants. The measured and modeled wave damping illustrated the dependences on the following meadow characteristics: shoot density, stem length, stem diameter, leaf width, leaf thickness, number of leaves, elastic modulus of the leaves and the stem, and the sheltering effect between the leaves and the stem.