An experimental study on sediment transport and bed evolution under different swash zone morphological conditions

Alsina, Jose M., Caceres, Ivan, Brocchini, Maurizio and Baldock, Tom E. (2012) An experimental study on sediment transport and bed evolution under different swash zone morphological conditions. Coastal Engineering, 68 31-43. doi:10.1016/j.coastaleng.2012.04.008

Author Alsina, Jose M.
Caceres, Ivan
Brocchini, Maurizio
Baldock, Tom E.
Title An experimental study on sediment transport and bed evolution under different swash zone morphological conditions
Journal name Coastal Engineering   Check publisher's open access policy
ISSN 0378-3839
Publication date 2012-10-01
Year available 2012
Sub-type Article (original research)
DOI 10.1016/j.coastaleng.2012.04.008
Open Access Status Not yet assessed
Volume 68
Start page 31
End page 43
Total pages 13
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Subject 2305 Environmental Engineering
2212 Ocean Engineering
Abstract In this study, new large‐scale experimental data are presented showing evidences of a link between the swash zone dynamics and the surf zone morphodynamics. Two sets of large‐scale experiments are presented. The first set of experiments investigates the swash and surf dynamics under the same hydrodynamic forcing but with two different swash zone morphological conditions, one of which was created by manual reshaping of the sub-aerial beach face. It is shown that more dissipative swash zone conditions (a more mildly sloping beach face) significantly reduce the rate of seaward sandbar migration such that it almost ceases during the performed experimentation time. This behavior is compared to a second set of experiments which shows the natural sand bar offshore migration under almost identical hydrodynamic forcing. The changes in the sandbar migration are investigated in terms of the differences in the swash zone dynamics. The more reflective swash zone is characterized by more intense backwashes that, in turn, promote significant quantities of sediment suspension during the interaction of the backwash with the subsequent bore. The dissipative swash zone leads to a larger number of wave–swash interactions, reducing the backwash magnitudes and the magnitude of suspended sediment concentration events in the swash zone, with a corresponding reduction in the offshore suspended sediment transport. The total offshore sediment transport rates are also shown to reduce, leading to the observed modification of the sandbar migration.
Keyword Swash zone
Bar migration
Sediment transport
Suspended sediment concentration
Large-scale experiments
Wave-swash interactions
Suspended Sediment
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID 022441 936-RII3
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
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