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Communication Dans Un Congrès Année : 2019

The sensitivity of coastal flood to the stochastic character of waves

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Résumé

Today, numerical modeling of coastal flood in urban area mainly accounts for overflow, and most of studies accounting for overtopping use time empirical formula of overtopping discharges. Recent progresses allow to model each wave and to account for the overtopping processes. In addition, such models are forced by the still water level and wave parameters or wave spectrum. However, an infinite number of time series are compliant with each single wave spectrum. While time series covering about 500 waves lead to similar wave properties and overtopping discharges, the still water level can significantly change in macro-tidal areas in a time lapse of 500 waves (e.g. in about 1.4 h for 10s mean wave period). Thus, we could expect the stochastic character of waves to have a sizeable effect on overtopping-induced coastal flooding. The present paper investigates the sensitivity of coastal flood to this stochastic character of waves. We use the SWASH model to reproduce the past flooding events of the 10th of March 2008 in Gâvres (French Atlantic coast), which led to about 120 flooded houses. To investigate the effect of the stochastic character of waves, the model is runs 10 times with seeds chosen randomly. The results show that inland flood water volume vary of about 10%, and lead to significant changes inland water height and flood extension. The magnitude of this effect on the flood is sizeable to the changes in flood hazards expected from sea-level rise by the middle of the 21st century.
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Dates et versions

hal-02100343 , version 1 (18-01-2022)

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  • HAL Id : hal-02100343 , version 1

Citer

Déborah Idier, Rodrigo Pedreros, Jeremy Rohmer, Sylvestre Leroy, Gonéri Le Cozannet. The sensitivity of coastal flood to the stochastic character of waves. 27th International Union of Geodesy and Geophysics - IUGG 2019, Jul 2019, Montréal, Canada. pp.IUGG19-4638. ⟨hal-02100343⟩

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