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Experimental study on vegetation flexibility as control parameter for wave damping and velocity structure / Thomas van Veelen; Tom Fairchild; Dominic Reeve; Harshinie Karunarathna

Coastal Engineering, Volume: 157, Start page: 103648

Swansea University Authors: Thomas, van Veelen, Tom, Fairchild, Dominic, Reeve, Harshinie, Karunarathna

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Abstract

Vegetation can contribute to coastal defence by damping incoming waves. However, prior studies have shown that attenuation varies greatly among plant species. Plant flexibility is a mechanical property that is commonly omitted, but varies greatly between shrubs and grasses on salt marshes. Therefore...

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Published in: Coastal Engineering
ISSN: 0378-3839
Published: Elsevier BV 2020
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa53312
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Abstract: Vegetation can contribute to coastal defence by damping incoming waves. However, prior studies have shown that attenuation varies greatly among plant species. Plant flexibility is a mechanical property that is commonly omitted, but varies greatly between shrubs and grasses on salt marshes. Therefore, we present an experimental study in a laboratory wave flume with artificial vegetation that differs in flexibility only. We measured wave attenuation and water particle velocities around rigid and flexible salt marsh vegetation. Waves were measured using a series of gauges and Particle Image Velocimetry (PIV) was used to measure spatio-temporal variations of water particle velocities in the - plane around the vegetation. Our results show that flexible vegetation attenuates waves up to 70% less than rigid vegetation due to swaying of flexible plants. Furthermore, we find that rigid vegetation modifies the velocity structure, whereas flexible vegetation does not. Specifically, a mean current in the direction of wave propagation develops around the canopy and the horizontal particle velocities are amplified directly above the canopy. These results indicate that plant flexibility is a key parameter in the wave-vegetation interaction that controls wave damping and the velocity structure.
Keywords: Salt marsh vegetation; Wave damping; Plant flexibility; PIV-Measurements; Flow velocities
Start Page: 103648