Banks with subnatural lagoons (Constructed wetland) were created (2010) by VNF (Waterways of France), as a countervailable to set wide gauge of the Scheldt in the north of France, on the edge of the river. The lagoon is divided into meanders in order to extend the ecotone soil-water and purifying water of the Scheldt. It is powered by the Scheldt itself passively or more "active" during the passage of boats (which produces a wave with pressure and depression).