Spatial and temporal variability of shorefaces: A morpho-hydrodynamic controlled system

Klervi Hamon-Kerivel, DWT Jackson, Emilia Guisado-Pintado, Andrew Cooper, Mouncef Sedrati

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
52 Downloads (Pure)

Abstract

Shorefaces are transitional zones between the shelf and surfzone/beach systems. They are subdivided into ‘upper’ and ‘lower’ shoreface sectors which display particular morphodynamic behaviour, with the upper shoreface morphologically active over short (annual) time scales, and the lower shoreface evolving over much longer time scales (decadal and beyond). We examine morphodynamics using three distinct examples from the high-energy coast of Ireland. Numerical wave modelling (SWAN) is used to characterize wave energy dissipation across the shoreface. Our results show that zonation patterns and the physical extent of shorefaces display distinct spatial as well as temporal variations. The shoreface's physical limits and internal zonation patterns are driven by the combination of local wave forcing and pre-existing shoreface morphology. Shoreface behaviour therefore, falls within a spectum between gradual and intensive wave energy dissipation. We show that particular seabed morphology controls the extent of, as well as the bed shear stress distribution across the shoreface. This can have significant implications for any adjoining beach systems as waves arriving at the surf zone acquire specific characteristics depending on the shoreface configuration, even under similar offshore wave conditions. Additionally, the variation of shoreface extent impacts the volume of sediment available for transport, both to the nearshore zone as well as local beach systems. The influence of shoreface morphology is therefore an important, but largely overlooked element in the study of mesoscale coastal behaviour as well as coastal response to global climate change and secular sea-level rise.

Original languageEnglish
Article number108162
Pages (from-to)1-10
Number of pages10
JournalEstuarine Coastal and Shelf Science
Volume281
Early online date8 Dec 2022
DOIs
Publication statusPublished (in print/issue) - 5 Feb 2023

Bibliographical note

Funding Information:
This work was supported through funding from a DfE International research Award to Klervi Hamon-Kerivel. This research is a contribution the UNESCO IGCP 725 project “Forecasting Coastal Change”.

Publisher Copyright:
© 2022

Keywords

  • Shoreface zonation
  • Shoreface extent
  • Depth of Closure
  • Bed Shear Stress
  • Nearshore morphology

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