Sand transport processes and bed level changes induced by two alternating laboratory swash events
File(s)vanderZanden_ea_2019_CENG_accepted.pdf (3.49 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
Sand transport processes and net transport rates are studied in a large-scale laboratory swash zone. Bichromatic waves with a phase modulation were generated, producing two continuously alternating swash events that have similar offshore wave statistics but which differ in terms of wave-swash interactions. Measured sand suspension and sheet flow dynamics show strong temporal and spatial variability, related to variations in flow velocity and locations of wave capture and wave-backwash interactions. Suspended and sheet flow layer transport rates in the lower swash zone are generally of same magnitude, but sheet flow exceeds the suspended load transport by up to a factor four during the early uprush. The bed level near the inner surf zone is relatively steady during a swash cycle, but changes of (cm/s) are measured near the mid swash zone where wave-swash interactions lead to strongly non-uniform flows. The two alternating swash events produce a dynamic equilibrium, with bed level changes up to a few mm induced by single swash events, but with net morphodynamic change over multiple events that is two orders of magnitude lower. Most of the intra-swash and the single-event-averaged bed level changes in the swash zone are caused by a redistribution of sediment within the swash. The transport of sediment across the surf-swash boundary is minor at intra-swash time scale, but becomes increasingly significant at swash-averaged time scales or longer (i.e., averaged over multiple swash events).
Date Issued
2019-10
Date Acceptance
2019-06-27
Citation
Coastal Engineering, 2019, 152, pp.1-20
ISSN
0378-3839
Publisher
Elsevier BV
Start Page
1
End Page
20
Journal / Book Title
Coastal Engineering
Volume
152
Copyright Statement
© 2019 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S0378383919300146?via%3Dihub
Subjects
0403 Geology
0405 Oceanography
0905 Civil Engineering
Oceanography
Publication Status
Published
Article Number
103519
Date Publish Online
2019-07-02