Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/32767
Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Geologically constrained morphological variability and boundary effects on embayed beaches
Author(s): Loureiro, Carlos
Ferreira, Óscar
Cooper, J Andrew G
Contact Email: carlos.loureiro@stir.ac.uk
Keywords: coastal embayment
geological control
hard-bottom
empirical orthogonal functions
hydrodynamic forcing
Issue Date: 1-Nov-2012
Date Deposited: 17-Sep-2019
Citation: Loureiro C, Ferreira Ó & Cooper JAG (2012) Geologically constrained morphological variability and boundary effects on embayed beaches. Marine Geology, 329-331, pp. 1-15. https://doi.org/10.1016/j.margeo.2012.09.010
Abstract: Headlands, rock outcrops and engineering structures impact beach and nearshore dynamics of coastal embayments, inducing boundary effects that constrain the lateral and vertical beach variability. This study analyses morphological change in six embayed beaches with diverse levels of exposure to wave action and various degrees of geological control in the mesotidal coast of southwestern Portugal. The aim is to identify whether geological boundaries constrain the morphological behaviour of embayed beaches and assess whether their effects can be decoupled from datasets of morphological change. Topographic data, obtained over a two-year period on each of the six embayments, were analysed using empirical orthogonal functions (EOF) to decompose temporal and spatial variability in the datasets. First and second mode eigenfunctions were explored using time-variable linear correlation analysis with several nearshore parameters that include hydrodynamic variables, sedimentary and geometric characteristics of each embayment in order to derive forcing–response relationships. Our results demonstrate that natural geological boundaries constrain the morphological behaviour of embayed beaches, producing conspicuous alongshore variability in all embayments. Localised responses induced by lateral and vertical boundary interference with beach and nearshore dynamics include beach rotation, topographically-controlled rip circulation and restrained profile fluctuation. Spatial decoupling in cross- and longshore responses is accompanied by a temporal decoupling in response times, both of which are slower in more constrained embayments (from 1 day in exposed embayments to 1 week or more in the most sheltered ones). Normalised wave power was correlated at the 99% confidence level with the primary mode of morphological variability at most embayments, which represent 67% to 94% of the variance in the datasets. This correlation stresses the importance of combined parameterization of wave and tide forcing in process–response relations between hydrodynamics and morphological change for mesotidal coastal environments. Lateral and vertical geological boundaries exert their effects fundamentally by restraining longshore sediment transport, inducing cellular surf zone circulation and by impacting cross-shore sediment transport. It is postulated that decreasing sediment abundance and substrate depth intensify vertical boundary effects, while higher indentation and wave obliquity enhance the effects of lateral boundaries.
DOI Link: 10.1016/j.margeo.2012.09.010
Rights: [Loureiro_etal_2012b_PostPrintAuthorVersion.pdf] This post-print author’s version of the manuscript is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
[Loureiro_etal_2012b_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.
Licence URL(s): http://creativecommons.org/licenses/by-nc-nd/4.0/

Files in This Item:
File Description SizeFormat 
Loureiro_etal_2012b_PostPrintAuthorVersion.pdfFulltext - Accepted Version3.31 MBAdobe PDFView/Open
Loureiro_etal_2012b_PublishedVersion.pdfFulltext - Published Version3.15 MBAdobe PDFUnder Permanent Embargo    Request a copy



This item is protected by original copyright



A file in this item is licensed under a Creative Commons License Creative Commons

Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

The metadata of the records in the Repository are available under the CC0 public domain dedication: No Rights Reserved https://creativecommons.org/publicdomain/zero/1.0/

If you believe that any material held in STORRE infringes copyright, please contact library@stir.ac.uk providing details and we will remove the Work from public display in STORRE and investigate your claim.