ORCID
- Gerd Masselink: 0000-0001-6079-7611
- Mark Wiggins: 0000-0003-2232-7680
- Lauren Biermann: 0000-0002-6995-7586
Abstract
Understanding and predicting the morphodynamic evolution of gravel barrier systems is essential for coastal management, as these features provide natural protection for infrastructure and ecosystems. This study uses the composite gravel barrier system of Westward Ho!, south west England, characterised by a sandy intertidal region and a gravel high tide ridge, to quantify the morphological behaviour of this barrier system and link the dynamics to the external forcing, notably sea-level rise and waves. Since 1887, the barrier has retreated by 97 m, with an average retreat rate of 0.71 m yr−1. Over the period 2007–2024, the system lost approximately 216,000 m3 of sediment, equivalent to 3.6 m3 m−1 yr−1. It is suggested that most of this material was transported to a beach-dune system north of the barrier, across an estuary. Over the past two decades, the retreat rate of the southern section has slowed to 0.18 m yr−1, while the retreat rate of the northern section has increased to 2.39 m yr−1. This suggests segmentation is occurring, with the southern end becoming swash-aligned and the northern end drift-aligned. Morphological changes did not strongly correlate with SLR or wave power (cross-shore or longshore). The low-tide shoreline appears near equilibrium with prevailing wave direction, but the gravel ridge is slightly misaligned, suggesting net northward sediment transport. Given current trends, the barrier is expected to continue retreating and losing sediment for several decades. However, a comprehensive understanding of the system's future behaviour requires development of a mixed-sediment morphodynamic model.
DOI Link
Publication Date
2026-02-01
Publication Title
Marine Geology
Volume
492
ISSN
0025-3227
Acceptance Date
2025-11-23
Deposit Date
2026-02-02
Funding
CLR was funded by a Doctoral Research Account awarded by the School of Biological and Marine Sciences, University of Plymouth, and GM was supported by the NERC Strategic Highlight Topics grant, Building understanding of natural coastal protection by gravel barriers in a changing climate (#gravel) (NE/Y50323X/1).
Keywords
gravel barrier, sea-level rise, coastal erosion, longshore transport, beach morphodynamics
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Rimmer, C., Masselink, G., Wiggins, M., & Biermann, L. (2026) 'Morphodynamics of a composite barrier system, Westward Ho!, North Devon, UK', Marine Geology, 492. Available at: 10.1016/j.margeo.2025.107684
