Coastal risks:Numerical and experimental study of extreme wave impacts on temporary flood-fighting structures

The Grande Plage of Biarritz has experienced several extreme storm events over the past decades causing significant damage to the infrastructures and buildings located on the beachfront.

These events have led to the implementation of a protection strategy for infrastructure, which includes the implementation of a removable dike made of sandbags on the seawall located at the top of the beach.
This study presents the results of a measurement campaign conducted during the Justine storm on January 31, 2021, which severely affected the Basque coastline. The measurement device setup includes a series of pressure sensors fixed at the foot of the seawall on which two rows of sandbags had been strapped.

These sensors are used to determine the occurrences of overtopping events and their associated heights. Hydrodynamics on the foreshore are studied using the phase resolved wave model, BOSZ, which is used to estimate the mechanical forces exerted on the sandbags during the overtopping episodes and try to bring first elements of understanding of the hydrodynamic processes that may be responsible for the very localized sandbag movements observed during this storm.
Auteurs: Mohamed ROZKI,  Denis MORICHON, Matthias DELPEY, Stéphane ABADIE.