Storm extreme levels and coastal flood hazards: A parametric approach on the French coast of Languedoc (district of Leucate)

Anselme, Brice; Durand, Paul; Thomas, Yves-François; Nicolae-Lerma, Alexandre

doi:10.1016/j.crte.2011.07.006

Cited by 24 publications

(12 citation statements)

References 28 publications

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“…Energetic waves can elevate total water level (combined setup and runup) by as much as 3 m [ Stockdon et al , 2006]. Empirical parameterizations of wave‐induced setup

\overset{R}{true}

(super‐elevation of the mean shoreline location) and runup (fluctuations of the waterline about the mean) are often used to predict coastal flooding and erosion [ Ruggiero et al , 2001; Anselme et al , 2011; Revell et al , 2011]. Runup often is divided into sea‐swell (0.04–0.3 Hz, R s (ss) ) and infragravity (0.004–0.04 Hz, R s (ig) ) frequency bands, with significant runup elevation R s defined as 4 σ , where σ 2 is the vertical runup variance in that band.…”

Section: Introductionmentioning

confidence: 99%

Effect of wave frequency and directional spread on shoreline runup

Guza

Feddersen

2012

Geophysical Research Letters

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[1] Wave breaking across the surf zone elevates the mean water level at the shoreline (setup), and drives fluctuations about the mean (runup). Runup often is divided into seaswell (0.04-0.3 Hz) and lower frequency infragravity (0.00-0.04 Hz) components. With energetic incident waves, runup is dominated by infragravity frequencies, and total water levels (combined setup and runup) can exceed 3 m, significantly contributing to coastal flooding and erosion. Setup and runup observations on sandy beaches are scattered about empirical parameterizations based on near-shoreline beach slope and deep water wave height and wavelength. Accurate parameterizations are needed to determine flooding and erosion risk to coastal ecosystems and communities. Here, numerical simulations with the Boussinesq wave model funwaveC are shown to statistically reproduce typical empirical setup and runup parameterizations. Furthermore, the model infragravity runup R s (ig) strongly depends on the incident wave directional and frequency spread (about the mean direction and peak frequency). Realistic directional spread variations change R s (ig) equivalent to a factor of two variation in incident wave height. The modeled R s (ig) is shown to vary systematically with a new, non-dimensional spreading parameter that involves peak frequency, frequency spread, and directional spread. This suggests a new parameterization for R s (ig) potentially useful to predict coastal flooding and erosion. Citation: Guza, R. T., and F. Feddersen (2012), Effect of wave frequency and directional spread on shoreline runup, Geophys.

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“…Energetic waves can elevate total water level (combined setup and runup) by as much as 3 m [ Stockdon et al , 2006]. Empirical parameterizations of wave‐induced setup

\overset{R}{true}

Section: Introductionmentioning

confidence: 99%

Effect of wave frequency and directional spread on shoreline runup

Guza

Feddersen

2012

Geophysical Research Letters

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“…Flooding from a marine origin (related to changing sea level) can be the result of a marine storm associated with a short-term scale (Benavente et al 2006;Anselme et al 2011;Bosom and Jiménez 2011). Regarding flooding from the same source, but associated with a long-term scale, the effect of climate change can cause a permanent inundation due to SLR (Nicholls et al 1999).…”

Section: Introductionmentioning

confidence: 99%

A multi-component flood risk assessment in the Maresme coast (NW Mediterranean)

2017

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Coastal regions are the areas most threatened by natural hazards, with floods being the most frequent and significant threat in terms of their induced impacts, and therefore, any management scheme requires their evaluation. In coastal areas, flooding is a hazard associated with various processes acting at different scales: coastal storms, flash floods, and sea level rise (SLR). In order to address the problem as a whole, this study presents a methodology to undertake a preliminary integrated risk assessment that determines the magnitude of the different flood processes (flash flood, marine storm, SLR) and their associated consequences, taking into account their temporal and spatial scales. The risk is quantified using specific indicators to assess the magnitude of the hazard (for each component) and the consequences in a common scale. This allows for a robust comparison of the spatial risk distribution along the coast in order to identify both the areas at greatest risk and the risk components that have the greatest impact. This methodology is applied on the Maresme coast (NW Mediterranean, Spain), which can be considered representative of developed areas of the Spanish Mediterranean coast. The results obtained characterise this coastline as an area of relatively low overall risk, although some hot spots have been identified with high-risk values, with flash flooding being the principal risk process.

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“…The first was to apply the recommendations of the French Risk Prevention Plan using a fixed elevation and available observations from tide gauges along the French Mediterranean coast (DREAL, 2008). Subsequently, Anselme et al (2011) showed that the additional water height caused by wave setup and runup has to be taken into account to approach the values observed during past storms and to characterize the hazards to the seafront. However, the parametric method applied cannot be used to consider the hazard in zones not directly exposed to waves, such as harbour zones where the flooding pattern is different (O flow ).…”

Section: Discussionmentioning

confidence: 99%

“…In some cases, the estimated value can vary by as much as an order of magnitude (Lynett et al, 2010). These estimated uncertainties as to the reproduction of overtopping volumes can also be attributed to the inadequacy of validation data, which are often qualitative and partial (Battjes and Gerritsen, 2002;Poulter and Halpin, 2008;Reeve et al, 2008;Anselme et al, 2011;Gallien et al, 2012).…”

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confidence: 99%

High-resolution marine flood modelling coupling overflow and overtopping processes: framing the hazard based on historical and statistical approaches

Lerma¹,

Bulteau²,

Elineau³

et al. 2018

Nat. Hazards Earth Syst. Sci.

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Abstract. A modelling chain was implemented in order to propose a realistic appraisal of the risk in coastal areas affected by overflowing as well as overtopping processes. Simulations are performed through a nested downscaling strategy from regional to local scale at high spatial resolution with explicit buildings, urban structures such as sea front walls and hydraulic structures liable to affect the propagation of water in urban areas. Validation of the model performance is based on hard and soft available data analysis and conversion of qualitative to quantitative information to reconstruct the area affected by flooding and the succession of events during two recent storms. Two joint probability approaches (joint exceedance contour and environmental contour) are used to define 100-year offshore conditions scenarios and to investigate the flood response to each scenario in terms of (1) maximum spatial extent of flooded areas, (2) volumes of water propagation inland and (3) water level in flooded areas. Scenarios of sea level rise are also considered in order to evaluate the potential hazard evolution. Our simulations show that for a maximising 100-year hazard scenario, for the municipality as a whole, 38 % of the affected zones are prone to overflow flooding and 62 % to flooding by propagation of overtopping water volume along the seafront. Results also reveal that for the two kinds of statistic scenarios a difference of about 5 % in the forcing conditions (water level, wave height and period) can produce significant differences in terms of flooding like +13.5 % of water volumes propagating inland or +11.3 % of affected surfaces. In some areas, flood response appears to be very sensitive to the chosen scenario with differences of 0.3 to 0.5 m in water level. The developed approach enables one to frame the 100-year hazard and to characterize spatially the robustness or the uncertainty over the results. Considering a 100-year scenario with mean sea level rise (0.6 m), hazard characteristics are dramatically changed with an evolution of the overtopping / overflowing process ratio and an increase of a factor 4.84 in volumes of water propagating inland and 3.47 in flooded surfaces.

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Storm extreme levels and coastal flood hazards: A parametric approach on the French coast of Languedoc (district of Leucate)

Cited by 24 publications

References 28 publications

Effect of wave frequency and directional spread on shoreline runup

Effect of wave frequency and directional spread on shoreline runup

A multi-component flood risk assessment in the Maresme coast (NW Mediterranean)

High-resolution marine flood modelling coupling overflow and overtopping processes: framing the hazard based on historical and statistical approaches

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