Extreme erosion on high-energy embayed beaches: Influence of megarips and storm grouping

Loureiro, Carlos; Ferreira, Óscar; Cooper, J Andrew G; Fundacao para a Ciencia e Tecnologia; University of Algarve; University of Algarve; Ulster University; 0000-0003-3117-3492

Extreme erosion on high-energy embayed beaches: Influence of megarips and storm grouping

2011 | 2019 | 2012

Megarips have long been recognised as an important, yet poorly documented, mechanism of beach erosion on high-energy embayed beaches. The persistence and cumulative effect of megarips during storm groups, are described from three embayed beaches (Arrifana, Mt. Clérigo and Amoreira) exposed to high-energy wave conditions in the mesotidal, bedrock-dominated southwestern coast of Portugal. Morphological changes, determined by topographic monitoring and supplemented by interpretation of digital imagery over two years, revealed the development of storm-induced megarips, which exerted a major influence on beach erosion. Differences in megarip influence within and between beaches are related to embayment geometry and orientation,which significantly influence the nearshore wave field. Rip location is topographically controlled, being determined by alongshore variations in breaking wave height and obliquity, along with interaction of wave-driven circulation patterns and embayment nearshore topography. Moderate beach sand loss during individual storms was linked to the development of megarips with associated rip-neck and feeder channels. Extreme erosion, however, occurred when megarips and feeder channels persisted during successive storms, promoting continued erosion and seaward sediment export. Observations show that once initiated, megarip channels persist for several months and continue to act as conduits for offshore sediment transport under non-storm conditions. The maintenance of such rip circulation systems, driven by morphodynamic feedback, reduces beach recovery ability until the rip-neck and feeder channels are infilled.

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Mots clés AGROVOC

portugal

Informations bibliographiques

Editeur

Elsevier BV

D'autres materias

Megarips; Wave modelling; Embayed beaches; Storm groups; Beach morphology

Langue

anglais

Format

application/pdf, application/pdf

Licence

[Loureiro_etal_2012a_PostPrintAuthorVersion.pdf] This post-print author’s version of the manuscript is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 InternationalLicense, [Loureiro_etal_2012a_PublishedVersion.pdf] The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study., http://creativecommons.org/licenses/by-nc-nd/4.0/, [Loureiro_etal_2012a_PublishedVersion.pdf] The publisher does not allow this work to be made publicly available in this Repository therefore there is an embargo on the full text of the work.

ISBN

0003011581000, 0-848559901

Type

Journal Article; Am - Accepted Manuscript; Vor - Version Of Record

Sur AGRIS depuis: 2024-11-28

Format: Dublin Core

Fournisseur de données

Cette notice bibliographique a été fournie par University of Stirling

Découvrez la collection de ce fournisseur de données dans AGRIS

Liens

DOI http://hdl.handle.net/1893/32766 http://dspace.stir.ac.uk/retrieve/5dabbe25-fa94-4aa0-aa9f-89142648129d/Loureiro_etal_2012a_PostPrintAuthorVersion.pdf http://dspace.stir.ac.uk/retrieve/c5637ca9-85ef-496d-be53-22843c916441/Loureiro_etal_2012a_PublishedVersion.pdf

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