Redesign Seine-Scheldt-Leie – Harelbeke

This project is part of the large scale, cross-border Seine-Scheldt project that aims at a better naval connection of the Seine basin in the Paris region with the Scheldt basin in the Antwerp-Rotterdam region. In the future, it should be possible to sail ships up to 4,500 tons (CEMT class-Vb ships) from Paris to Antwerp, and vice versa.

On Flemish territory, the project mainly involves adapting the river Leie from a 1,350-tonne waterway to a 4,500-tonne waterway. For the Harelbeke project, this requires a deepening and bend widening of the navigation channel, several new bridges and quay walls, a new fish ladder, and a new lock and weir.

Assignment

Given the complexity of the project, the commissioning board has opted to put this assignment on the market as a Design & Build contract. The JV Leieland achieved the highest technical score and was the preferred bidder for this project. The assignment has therefore been awarded to the JV Leieland. Because the project is executed as D&B, SBE was involved from the beginning to the end of the project.

Rebuild the power locks

One of the crucial parts of the works in Harelbeke was the replacement of the lock and the weir. Due to high requirements concerning navigability during execution, hydraulics and historical value within its urban environment, it was decided to rebuild the new lock on the same location of the existing lock and using a temporary lock during execution.

For this to be possible, the following steps were necessary:

  • Construction of a new temporary weir on an old river meander
  • Connecting the current river bed to the old river meander and temporary weir, which served as hydraulic bypass during construction
  • Demolition of the old weir and construction of a new temporary lock at this location
  • Demolition of the old lock and construction of the new permanent lock at this location
  • Removing the temporary lock and construction of the new permanent weir at this location (which is also the location of the old weir)
  • Removing the temporary weir and construction of the fish ladder at this location

New lock

The new lock, being 230m long, 12.5m wide and 4.7m deep is longer, wider and deeper than the old lock, and is fitted with intermediate doors that divide the lock in 2 unequal parts. For smaller ships, only one part of the chamber will be used, so water spillage is minimised, and ships are channelled faster.

The 3 sets of doors are mitre gates with an oleo hydraulic pump unit. Lock filling/emptying happens through valves in the doors.