16 years of topographic surveys of rip-channelled high-energy meso-macrotidal sandy beach

Castelle, Bruno; Bujan, Stéphane; Marieu, Vincent; Ferreira, Sophie

doi:10.1038/s41597-020-00750-5

Cited by 50 publications

(37 citation statements)

References 77 publications

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“…For each approach, the ESM k +/− and respective parameters (a and b for Y09, and Φ for S14) are calibrated using the Simulated Annealing optimization technique [44] described in D'Anna et al [18] on Equation (4). Compared to D'Anna et al [18], who used the Truc Vert shoreline data up to 2017, the time series of mean shoreline position estimated here with topographic surveys is extended to the end of 2019 [45]. The calibration is performed over the period 01 January 2012-31 December 2019, which shows no long-term shoreline trend (Figure 7a).…”

Section: Test Casementioning

confidence: 99%

Reinterpreting the Bruun Rule in the Context of Equilibrium Shoreline Models

D'Anna

Idier

Castelle

et al. 2021

JMSE

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Long-term (>decades) coastal recession due to sea-level rise (SLR) has been estimated using the Bruun Rule for nearly six decades. Equilibrium-based shoreline models have been shown to skillfully predict short-term wave-driven shoreline change on time scales of hours to decades. Both the Bruun Rule and equilibrium shoreline models rely on the equilibrium beach theory, which states that the beach profile shape equilibrates with its local wave and sea-level conditions. Integrating these two models into a unified framework can improve our understanding and predictive skill of future shoreline behavior. However, given that both models account for wave action, but over different time scales, a critical re-examination of the SLR-driven recession process is needed. We present a novel physical interpretation of the beach response to sea-level rise, identifying two main contributing processes: passive flooding and increased wave-driven erosion efficiency. Using this new concept, we analyze the integration of SLR-driven recession into equilibrium shoreline models and, with an idealized test case, show that the physical mechanisms underpinning the Bruun Rule are explicitly described within our integrated model. Finally, we discuss the possible advantages of integrating SLR-driven recession models within equilibrium-based models with dynamic feedbacks and the broader implications for coupling with hybrid shoreline models.

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Section: Test Casementioning

confidence: 99%

Reinterpreting the Bruun Rule in the Context of Equilibrium Shoreline Models

D'Anna

Idier

Castelle

et al. 2021

JMSE

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“…Monthly-averaged significant wave height ranges from 1.1 m in August with dominant W-NW direction to 2.4 m in January with dominant W direction. Truc Vert beach has been intensively monitored since 2003 with monthly to bi-monthly topographic DGPS surveys, with additional daily topographic surveys and high-resolution bathymetric surveys collected during the ECORS'08 field campaign (Parisot et al, 2009), see Castelle et al (2020) for detailed description of the datasets. Since 2017, highresolution digital elevation model covering 4 km of beach-dune are also derived seasonally from photogrammetry of UAV images (Laporte-Fauret et al, 2019).…”

Section: Truc Vert Beachmentioning

confidence: 99%

Uncertainties in Shoreline Projections to 2100 at Truc Vert beach (France): Role of Sea-Level Rise and Equilibrium Model Assumptions

D'Anna

Castelle

Idier³

et al. 2021

Preprint

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 Ensemble-based simulations of future shoreline evolution to 2100, including sea-level rise driven erosion, are performed and analysed  Future shoreline projections uncertainties are initially controlled by modelling assumptions and after 2060 by sea-level rise uncertainties  The choice of wave-driven equilibrium modelling approach and incident wave chronology are critical to short/mid-term shoreline projections

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“…50-m depth, and have been extensively validated with field data (e.g. Castelle et al, 2020). The primary metocean variables used are: tidal elevation (η), significant wave height (H s ), mean wave period (T 02 ), wave direction (θ), temperature (T ), wind speed (U ), Insolation (I).…”

Section: Environmental Datamentioning

confidence: 99%

Comment on nhess-2021-36

2021

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A Bayesian network (BN) approach is used to model and predict shore-break related injuries and rip-current drowning incidents based on detailed environmental conditions (wave, tide, weather, beach morphology) on the high-energy Gironde coast, southwest France. Six years (2011)(2012)(2013)(2014)(2015)(2016)(2017) of boreal summer (June 15 -September 15) surf zone injuries (SZIs) were analysed, comprising 442 (fatal and non-fatal) drownings caused by rip currents and 715 injuries caused by shore-break waves.Environmental conditions at the time of the SZIs were used to train two separate Bayesian networks (BNs), one for rip current drownings and the other one for shore-break wave injuries, each one with a hidden hazard and exposure variables. Both BNs were tested for varying complexity using K-fold cross-validation based on multiple performance metrics. Validation (prediction) results slightly improve predictions of SZIs with a poor to fair skill based on a combination of different metrics. Shore-break related injuries appear more predictable than rip current drowning incidents as the shore-break BN systematically performed better than the rip current BN. Sensitivity and scenario analyses were performed to address the influence of environmental data variables and their interactions on exposure, hazard and resulting life risk. Most of our findings are in line with earlier SZI and physical hazard-based work, that is, that more SZIs are observed for warm sunny days with light winds, longperiod waves, with specifically more shore-break related injuries at high tide and for steep beach profiles, and more rip current drownings near low tide with near shore-normal wave incidence and strongly alongshore non-uniform surf zone morphology.The BNs also provided fresh insight, showing that rip current drowning risk is approximately equally distributed between exposure (variance reduction V r = 14.4%) and hazard (V r = 17.4%), while exposure of water user to shore-break waves is much more important (V r = 23.5%) than the hazard (V r = 10.9%). Large surf is found to decrease beachgoer exposure to shore-break hazard, while this is not observed for rip currents. Rapid change in tide elevation during days with large tidal range was also found to result in more drowning incidents, presumably because it favors the rapid onset of rip current activity and can therefore surprise unsuspecting bathers. We advocate that such BNs, providing a better understanding of hazard, exposure and life risk, can be developed to improve public safety awareness campaigns, in parallel with the development of more skillful risk predictors to anticipate high life-risk days.

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16 years of topographic surveys of rip-channelled high-energy meso-macrotidal sandy beach

Cited by 50 publications

References 77 publications

Reinterpreting the Bruun Rule in the Context of Equilibrium Shoreline Models

Reinterpreting the Bruun Rule in the Context of Equilibrium Shoreline Models

Uncertainties in Shoreline Projections to 2100 at Truc Vert beach (France): Role of Sea-Level Rise and Equilibrium Model Assumptions

Comment on nhess-2021-36

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