Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model

Headland and groyne sand bypassing greatly influences embayment dynamics at medium to long timescales, but is often disregarded or partially included in reduced-complexity shoreline models. This study explores how accounting for subaqueous sediment bypassing in a shoreline model affects mean embayed...

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Main Authors: Elsa Durand, Bruno Castelle, Déborah Idier, Vincent Marieu, Arthur Robinet, Thomas Guérin
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Journal of Marine Science and Engineering
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Online Access:https://www.mdpi.com/2077-1312/12/12/2266
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author Elsa Durand
Bruno Castelle
Déborah Idier
Vincent Marieu
Arthur Robinet
Thomas Guérin
author_facet Elsa Durand
Bruno Castelle
Déborah Idier
Vincent Marieu
Arthur Robinet
Thomas Guérin
author_sort Elsa Durand
collection DOAJ
description Headland and groyne sand bypassing greatly influences embayment dynamics at medium to long timescales, but is often disregarded or partially included in reduced-complexity shoreline models. This study explores how accounting for subaqueous sediment bypassing in a shoreline model affects mean embayed beach planshape and spatial variability. We implement a generic parametrization of sand bypassing in the LX-Shore model, with simulations on a synthetic embayment in two configurations: “full bypassing” (FB) where the sediments bypass the obstacle in the surfzone and beyond, and “shoreline bypassing” (SB) where bypassing occurs only when the shoreline extends beyond the obstacle. Time-invariant wave simulations show significant differences in updrift shoreline position between FB and SB. Simulations with time-varying wave angles and fixed wave height and period reveal that FB significantly impacts the embayment mean planform and spatial variability: FB reduces beach rotation by about 1/3, particularly under slightly oblique and slightly asymmetrical wave climates, and decreases shoreline curvature, especially under highly oblique wave climates. Downdrift shoreline erosion may be overestimated by up to 20% under SB. Our simulations provide new insight into the influence of subaqueous sand bypassing on embayed beach dynamics and emphasize the importance of including this process when modelling shoreline evolution in coastal embayments.
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spelling doaj-art-e5d5a1497d3f4735b79d453f021781782025-08-20T02:56:55ZengMDPI AGJournal of Marine Science and Engineering2077-13122024-12-011212226610.3390/jmse12122266Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline ModelElsa Durand0Bruno Castelle1Déborah Idier2Vincent Marieu3Arthur Robinet4Thomas Guérin5Univ. Bordeaux, CNRS, Bordeaux INP, EPOC, UMR 5805, F-33600 Pessac, FranceUniv. Bordeaux, CNRS, Bordeaux INP, EPOC, UMR 5805, F-33600 Pessac, FranceBureau de Recherches Géologiques et Minières (BRGM), 3 Avenue Guillemin, 45100 Orléans, FranceUniv. Bordeaux, CNRS, Bordeaux INP, EPOC, UMR 5805, F-33600 Pessac, FranceBureau de Recherches Géologiques et Minières (BRGM), 24 Avenue Léonard de Vinci, 33600 Pessac, FranceWaeles Marine Consultants, 53 rue du Commandant Groix, 29200 Brest, FranceHeadland and groyne sand bypassing greatly influences embayment dynamics at medium to long timescales, but is often disregarded or partially included in reduced-complexity shoreline models. This study explores how accounting for subaqueous sediment bypassing in a shoreline model affects mean embayed beach planshape and spatial variability. We implement a generic parametrization of sand bypassing in the LX-Shore model, with simulations on a synthetic embayment in two configurations: “full bypassing” (FB) where the sediments bypass the obstacle in the surfzone and beyond, and “shoreline bypassing” (SB) where bypassing occurs only when the shoreline extends beyond the obstacle. Time-invariant wave simulations show significant differences in updrift shoreline position between FB and SB. Simulations with time-varying wave angles and fixed wave height and period reveal that FB significantly impacts the embayment mean planform and spatial variability: FB reduces beach rotation by about 1/3, particularly under slightly oblique and slightly asymmetrical wave climates, and decreases shoreline curvature, especially under highly oblique wave climates. Downdrift shoreline erosion may be overestimated by up to 20% under SB. Our simulations provide new insight into the influence of subaqueous sand bypassing on embayed beach dynamics and emphasize the importance of including this process when modelling shoreline evolution in coastal embayments.https://www.mdpi.com/2077-1312/12/12/2266sand bypassingembayed beachreduced-complexity shoreline modelequilibrium beach planformrotationcurvature
spellingShingle Elsa Durand
Bruno Castelle
Déborah Idier
Vincent Marieu
Arthur Robinet
Thomas Guérin
Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model
Journal of Marine Science and Engineering
sand bypassing
embayed beach
reduced-complexity shoreline model
equilibrium beach planform
rotation
curvature
title Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model
title_full Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model
title_fullStr Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model
title_full_unstemmed Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model
title_short Influence of Rocky Obstacle Sand Bypassing on Embayed Beach Dynamics Using a Reduced-Complexity Shoreline Model
title_sort influence of rocky obstacle sand bypassing on embayed beach dynamics using a reduced complexity shoreline model
topic sand bypassing
embayed beach
reduced-complexity shoreline model
equilibrium beach planform
rotation
curvature
url https://www.mdpi.com/2077-1312/12/12/2266
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