Calibration Lys Reach 140 (Sint-Baafs-Vijve to Deinze)

The calibration (widening and deepening) of the Lys forms part of the broader Seine-Scheldt project. This includes the implementation of an inland navigation link for larger vessels (CEMT class Vb) between the Seine basin in the south (Paris, Rouen, Le Havre) and the Scheldt basin and the North Sea ports in the north (Antwerp, Ghent, Zeebrugge, Amsterdam, Rotterdam). The Lys axis as an inland waterway between Ghent and the French border has a total length of 71km and is divided into 7 sections or reaches (from downstream to upstream). The study area for the present project covers ‘Reach 140’ along the Lys, between the Sint-Baafs-Vijve lock (upstream) and the Noorderwal winding hole at Deinze (downstream). SBE is responsible for the entire study and the monitoring of the works.

In addition to the widening and deepening of the Lys, the banks will also be fitted out to optimize water management, nature, recreation, heritage, and landscape. Therefore, the necessary works for economic progress will be seized upon to give the banks the best possible configuration. This means that good ecological potential is achieved and that space for water is created again. In the project, a balance must always be found between the various disciplines: the nautical aspect, the landscape, the ecological and recreational aspects.

An extensive nautical study was carried out to reach 140 because the successive bends must not be too sharp for the passage of larger ships in the future. In addition, efforts are being made to create as much space as possible for the natural layout of the banks. The bridges and quay walls will be retained and are therefore a hard precondition for the nautical study. The new fairway axis serves as the basis for the development of the banks.

The purpose of the green banks is to create additional typical riverine habitat, resting or foraging areas for a variety of species. The interventions in favor of fish are worth mentioning, where the new banks offer spawning, resting, and foraging places. These are distributed along the entire length of the Lys and consist of a wide range of wetland areas and areas separated by the foreshores, resulting in different water depths, flow velocities, and vegetation. To prevent the foreshores from forming a barrier to both terrestrial and aquatic animals, reptiles, and amphibians, some fauna exit points have been designed. But land animals will also benefit from the new banks, due to the close link with the Lys. The new banks will significantly increase the recreational value for walkers and cyclists.

SBE focused on the nature-friendly design of the banks, as well as on the technical development. The foreshore was dimensioned for the wave loads that occur as a result of passing ships. The bank itself was fully designed taking into account the loads that may occur and the local preconditions. The balance between the various disciplines was considered in doing so.