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Location: Harelbeke
Discipline: Civil engineering & infrastructure, Port, river & hydraulic engineering
Period: 2011 - 2020

Redevelopment of the Leie and lock complex at Harelbeke

Leieleute: the official opening of the project

January 2020

Fish ladder finished

November 2019

Official opening of new weir lock, start demolition of temporary lock.

March 2018

Commissioning of temporary lock.

July 2016

Installation of high bridge.

January 2016

Commissioning of temporary weir

August 2015

Start of preparatory works on site

January 2015

Submission of building application file.

December 2013

Award to THV Leieland.

April 2013

Start of study of the D&B tender phase.

January 2011

In order to make the Seine-Scheldt section navigable for ships up to 4,500 tonnes, the river Lys in Harelbeke needed to be made deeper. The future-proofing of the water site was accompanied by a new lock and barrage complex, the construction of 3 new bridges (2 fixed and 1 movable), bank defences, quay walls, soil protection and the redevelopment of the immediate surroundings.

Rebuilding the lock and weir

One of the most radical and spectacular parts of the work in Harelbeke is the replacement of the lock and weir. The lock was scaled up to a length of 230 m, a width of 12.5 m and a depth of 4.7 m. The weir with its 2 turbines is installed next to the lock and supplies it with electricity all year round. This allows the intermediate doors to be operated;  these make it possible to open only one part of the chamber for smaller vessels to pass through, thus allowing them to be moved more quickly.

In order to keep the river Lys navigable during the works and to avoid flooding, a temporary lock and weir were built.

Work on the bridges

An extension of the waterway for larger vessels also requires an adaptation of the bridges running over it to have a clear height of at least 7 meters (over a width of 35 meters). The Hogebrug was therefore adapted to these standards. In addition, it was extended with a safe lane for vulnerable road users. As well as the Hogebrug, the Banmolensbrug—a fixed road bridge in the direction of the mills—was also tackled. A third new bridge, the Bloemmolensburg, was built as a movable bicycle bridge.

Construction of the Moleneiland with fish run

At this stage, the focus was mainly on the underwater inhabitants of the Lys. Under the ‘River restoration’ project section, the ecological potential of the river, which has been canalised for many years, was adapted and maximised. Where possible, nature-friendly bank defences were provided, cut-off ‘dead’ meanders were reconnected, and favourable conditions for fish migration were restored.

Reconstruction of the immediate surroundings

No half measures for Seine Schelde Flanders. The work on the waterway provided a good time to renew and refurbish the adjacent roads and sewers. Paying attention to vulnerable road users and the inclusion of green zones were key to this.

SBE tasks

  • Drawing up calculation notes for temporary and permanent constructions
  • The nautical study
  • Drawing up the necessary plans
  • Participating in consultation meetings


Get to know the people behind the project

Guy worked as a project engineer on this challenging project. Discover his story and, who knows, you may soon become his colleague. Go to our job page to view the vacancies available.