Publications scientifiques

Storm tide (combination of storm surge and the astronomical tide) flooding is a natural hazard with significant global social and economic consequences. For this reason, government agencies and stakeholders need storm tide flood maps to determine population and infrastructure at risk to present and future levels of inundation. Computer models of varying complexity are able to produce regional-scale storm tide flood maps and current model types are either static or dynamic in their implementation.

This study aims to quantify the vertical motions driving the decadal coastline mobility and their uncertainty at global scale. Multisatellite altimetry is combined with tide gauges and Global Positioning System (GPS) observations to evaluate the marine and crustal components of relative sea level variations. Vertical land motions and sea level variations are estimated simultaneously over the past 20 years for a network of 886 ground stations, with accuracies better than 1.7 mm/yr.

A model has been developed in order to estimate insurance-related losses caused by coastal flooding in France. The deterministic part of the model aims at identifying the potentially flood-impacted sectors and the subsequent insured losses a few days after the occurrence of a storm surge event on any part of the French coast. This deterministic component is a combination of three models: a hazard model, a vulnerability model, and a damage model.

Radar water level sensors provide several advantages over the older water level instruments. They require less effort to install than float-well, bubbler, or pressure sensor systems. Radar sensors require less maintenance than traditional water-level sensors because they are not in contact with the water. Because radar is a “non-contact” measurement method, it is not susceptible to being obstructed by sediment or debris and does not require that sediment be flushed from a stilling well. Radar water-level sensors may not work at all sites.

This paper presents an investigation into the use of a 2-dimensional laser scanner (LiDAR) to obtain measurements of wave processes in the inner surf and swash zones of a microtidal beach (Rousty, Camargue, France). The bed is extracted at the wave-by-wave timescale using a variance threshold method on the time series. Individual wave properties were then retrieved from a local extrema analysis. Finally, individual and averaged wave celerities are obtained using a crest-tracking method and cross-correlation technique, respectively, and compared with common wave celerity predictors.

Extreme sea levels along the Atlantic Iberian coast are determined through the development and application of a numerical model for tides and surges, followed by a statistical analysis of the model results. A recent statistical method is assessed using 131 years of data from the Brest tide gauge, and the number of years of data required for an accurate statistical analysis is estimated. The statistical method is extended to consider tide–surge interactions, but they are shown to be small in the study region.

Understanding estuarine sediment dynamics and particularly turbidity maximum dynamics is crucial for the management of these coastal systems. Various processes impact the formation, movement and structure of the turbidity maximum. Several studies have shown that tidal asymmetry and density gradients are responsible for the presence of this suspended sedimentary mass.

Recent dramatic events have allowed significant progress to be achieved in coastal flood modelling over recent years. Classical approaches generally estimate wave overtopping by means of empirical formulas or 1-D simulations, and the flood is simulated on a DTM (digital terrain model), using soil roughness to characterize land use. The limits of these methods are typically linked to the accuracy of overtopping estimation (spatial and temporal distribution) and to the reliability of the results in urban areas, which are places where the assets are the most crucial.