Launched in 2019, the collaborative project DUNES aims to improve knowledge of the sedimentary and biological dynamics of the dune ecosystems in the area of the future offshore wind farm off Dunkirk and its electrical connection.
In order to gain knowledge of the evolution of the underwater dunes with a high spatial and temporal resolution, eight bathymetric surveys were carried out between November 2019 and July 2021 to determine the topography of the seabed at three study sites, each with a surface area of 1 km². In addition, a current measurement campaign lasting more than a month was carried out in the spring of 2021, allowing the hydrodynamic processes at work in the area to be monitored.
The various data collected are currently being analysed, but the initial results of the morphological monitoring suggest that the underwater dunes in the Dunkirk area are very dynamic: they have moved continuously eastwards overall over the period studied, with variable migration speeds. Extreme events such as storms seem to influence this horizontal displacement dynamic with a variation in sediment thickness at a given point. These movements will be anticipated in order to optimise the installation and manage the maintenance of offshore wind farms and their electrical connection.