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Modified hydrodynamics in canopies with longitudinal gaps exposed to oscillatory flows

Longitudinal gaps are commonly found in aquatic canopies. While the ecological significance of gaps may be large, we know little about their impact on the hydrodynamics within the canopy. We used laboratory experiments to investigate the effect of longitudinal gaps within canopies exposed to a wave field. In rigid submerged and emergent vegetation, wave velocities were reduced compared to the case without vegetation. Flexible canopies also attenuated waves, but this attenuation was lower than for rigid canopies. The presence of the gap modified the mean current associated with the waves in both the gap and the lateral vegetation. A gap within a canopy of 5% solid plant fraction did not show differences in the wave attenuation between the gap and the lateral vegetation. In contrast, gaps within canopies of 10% solid plant fraction resulted in large differences between the gap and the lateral vegetation. In all the experiments, the effect of a gap within a canopy reduced the wave attenuation within the lateral vegetation adjacent to the gap when compared with a canopy without a gap. In canopies with rigid plants, the lateral vegetation modified the wave attenuation in the nearby gap. In contrast, the lateral flexible vegetation did not produce any effect on the wave attenuation of the adjacent gap. Canopy density, plant height and plant flexibility were critical for determining the hydrodynamics throughout the canopy and in the gap

This work was supported by Ministerio de Ciencia e Innovación of the Spanish Government through grant CGL2010-17289

© Journal of Hydrology, 2015, vol. 531, part 3, p. 840-849

Elsevier

Author: El Allaoui, Nazha
Oldham, Carolyn
Serra Putellas, Teresa
Soler i Ortega, Marianna
Colomer, Jordi
Pujol Company, M. Dolors
Date: 2015 December
Abstract: Longitudinal gaps are commonly found in aquatic canopies. While the ecological significance of gaps may be large, we know little about their impact on the hydrodynamics within the canopy. We used laboratory experiments to investigate the effect of longitudinal gaps within canopies exposed to a wave field. In rigid submerged and emergent vegetation, wave velocities were reduced compared to the case without vegetation. Flexible canopies also attenuated waves, but this attenuation was lower than for rigid canopies. The presence of the gap modified the mean current associated with the waves in both the gap and the lateral vegetation. A gap within a canopy of 5% solid plant fraction did not show differences in the wave attenuation between the gap and the lateral vegetation. In contrast, gaps within canopies of 10% solid plant fraction resulted in large differences between the gap and the lateral vegetation. In all the experiments, the effect of a gap within a canopy reduced the wave attenuation within the lateral vegetation adjacent to the gap when compared with a canopy without a gap. In canopies with rigid plants, the lateral vegetation modified the wave attenuation in the nearby gap. In contrast, the lateral flexible vegetation did not produce any effect on the wave attenuation of the adjacent gap. Canopy density, plant height and plant flexibility were critical for determining the hydrodynamics throughout the canopy and in the gap
This work was supported by Ministerio de Ciencia e Innovación of the Spanish Government through grant CGL2010-17289
Format: application/pdf
ISSN: 0022-1694
Document access: http://hdl.handle.net/10256/13679
Language: eng
Publisher: Elsevier
Collection: MICINN/PN 2011-2013/CGL2010-17289
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.jhydrol.2015.10.041
Articles publicats (D-F)
Is part of: © Journal of Hydrology, 2015, vol. 531, part 3, p. 840-849
Rights: Tots els drets reservats
Subject: Hidrodinàmica
Hydrodynamics
Ones
Waves
Title: Modified hydrodynamics in canopies with longitudinal gaps exposed to oscillatory flows
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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