Large-scale experiments on wave propagation over Posidonia oceanica

Abstract

Posidonia oceanica, the most abundant seagrass species in the Mediterranean, supports a highly bio-diverse habitat and is crucial in protecting against coastal erosion. In this work, experiments in a large-scale facility have been performed, for the measurement of wave attenuation, transmission and energy dissipation over artificial Posidonia oceanica. The effects of submergence ratio corresponding to the seagrass height divided by water depth, and seagrass density as the number of stems per square metre on the above characteristics are investigated. Measurements of wave height at different locations along the vegetation meadow indicate the wave attenuation along the Posidonia oceanica for three different submergence ratios and two seagrass densities. Results are also analysed with regard to the wave-induced flow within the meadow, and the effects of the submergence ratio and the seagrass density on the mean flow characteristics, based on data of mean velocities taken at three locations within the seagrass.

Keywords:

• Artificial seagrass
• artificial vegetation
• large-scale experiment
• Posidonia oceanica
• wave attenuation
• wave–seagrass interaction

Acknowledgements

This study was conducted within the frame of Hydralab III 022441 (RII3) EU project. The authors gratefully acknowledge the assistance of the CIEM laboratory staff. The first author would like to acknowledge her Ph.D. funding grant by the Research Foundation Flanders, Belgium [Fonds voor Wetenschappelijk Onderzoek Vlaanderen (FWO)].