Exploring nearshore bed dynamics of a mixed beach using the depth of closure conceptual model
Exploring nearshore bed dynamics of a mixed beach using the depth of closure conceptual model
Mixed sediment beaches are globally commonplace, yet little is understood of the extent and behaviour of their nearshore zones, potentially underestimating total cross-shore change. This paper is the first study to investigate the lateral and vertical extent of the active zone of the gravel-rich mixed beach in Pevensey Bay, a study site on the South East UK coastline. Morphodynamic change in the nearshore zone was studied at a range of timescales (days, months, years) suggesting that the width of the active nearshore zone correlated with the magnitude of the peak morphological change, whilst the depth of closure was influenced by bed slope, grain size and local variation in wave conditions. A conceptual model detailing the physical parameters responsible for local variations in the depth of closure was used to help understand differences between the observed and predicted depths of closure. Finally, ongoing chronic loss of sediment from below Mean Sea Level (MSL) was examined, which was shown to be independent of the depth of closure, but closely linked to the wider geomorphic setting of the bay.
Coastal steepening, Depth of closure, Mixed beaches, Nearshore morphology
Townsend, Dominique
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Leyland, Julian
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Kassem, Hachem
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Thompson, Charlie
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Townend, Ian
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27 March 2024
Townsend, Dominique
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Leyland, Julian
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Kassem, Hachem
6c64fa27-a9f0-4bb8-8b1f-6c8c70480030
Thompson, Charlie
2a304aa6-761e-4d99-b227-cedb67129bfb
Townend, Ian
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Townsend, Dominique, Leyland, Julian, Kassem, Hachem, Thompson, Charlie and Townend, Ian
(2024)
Exploring nearshore bed dynamics of a mixed beach using the depth of closure conceptual model.
Geomorphology, 454, [109150].
(doi:10.1016/j.geomorph.2024.109150).
Abstract
Mixed sediment beaches are globally commonplace, yet little is understood of the extent and behaviour of their nearshore zones, potentially underestimating total cross-shore change. This paper is the first study to investigate the lateral and vertical extent of the active zone of the gravel-rich mixed beach in Pevensey Bay, a study site on the South East UK coastline. Morphodynamic change in the nearshore zone was studied at a range of timescales (days, months, years) suggesting that the width of the active nearshore zone correlated with the magnitude of the peak morphological change, whilst the depth of closure was influenced by bed slope, grain size and local variation in wave conditions. A conceptual model detailing the physical parameters responsible for local variations in the depth of closure was used to help understand differences between the observed and predicted depths of closure. Finally, ongoing chronic loss of sediment from below Mean Sea Level (MSL) was examined, which was shown to be independent of the depth of closure, but closely linked to the wider geomorphic setting of the bay.
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Accepted/In Press date: 9 March 2024
e-pub ahead of print date: 13 March 2024
Published date: 27 March 2024
Keywords:
Coastal steepening, Depth of closure, Mixed beaches, Nearshore morphology
Identifiers
Local EPrints ID: 488251
URI: http://eprints.soton.ac.uk/id/eprint/488251
ISSN: 0169-555X
PURE UUID: c0fb2950-0d53-4867-850d-7dee6d703eed
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Date deposited: 19 Mar 2024 17:38
Last modified: 19 Apr 2024 01:39
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Author:
Dominique Townsend
Author:
Hachem Kassem
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