L’écluse de Limmel

Rijkswaterstaat – the executive agency of the Dutch Ministry of Infrastructure and Environment – entrusted BESIX with the construction of the Limmel flood barrier. Our experience in lock construction enabled us to submit a detailed quality plan, explaining the safety aspects and disruptions during and after the project. 

Together with Agidens Infra Automation (now BESIX Unitec), which took care of the mechanical dimension of the project, and Rebel Group, providing financial advice, we were responsible for the design, construction, financing and maintenance of the flood barrier. This in itself was already a first: never before had one party been entrusted with the construction and maintenance of a whole flood barrier for such a long time. And this was good news as it allowed us to work more efficiently and learn from one another.

Our responsibilities:

• Design and construction of the new flood barrier

• Demolition of the old flood gate

• Maintenance of the complex

• Attract and follow up funding 

Rijkswaterstaat gave us the opportunity to explore innovative solutions. Together with Agidens we designed a simple yet powerful hydraulic lifting mechanism to move the lock gate. We implemented a smart solution to avoid leaks: by anchoring the dam walls on each of the four sides of the new flood gate in the limestone rock bed, we created a watertight container.

This is the third time BESIX builds such a flood barrier. Nevertheless, this project also has its own challenges, including the very limited room for manoeuvring when carrying out major lifting operations due to the presence of the existing floodgate. It was also crucial to minimize disruption to ship traffic on the busy Meuse during the works. Except for two weekends, freight traffic remained uninterrupted throughout the entire period. To ensure this, we first built the new lock, and we only demolished the old one after that, also making sure the Limburg hinterland would remain optimally protected during the works.

The Limmel flood barrier is an eighty-year-old barrier in the Juliana canal near Maastricht. It is an important link in the Maas Route connecting Belgium, the Netherlands, Germany and France and offering protection against the risk of flooding.

The flood barrier was not just due for replacement - its function was also to be fulfilled in a different way. It now acts as a flood barrier protecting the Juliana Canal and the area behind it in case the river Meuse breaks its banks.

The flood barrier formed a bottleneck for the constantly increasing volume of traffic on the waterway. To create more room for cargo vessels, BESIX began by replacing the old bridge that spanned the flood barrier. The new one does not go over, but next to the floodgate and has no supports in the water. This creates more space without widening the actual canal. The new bridge is also higher: vessels up to 9 metres high can pass under it easily.

In the design, BESIX allowed for the Juliana Canal to be closed just four times, for a maximum of 24 hours on each occasion. The elements of the new flood barrier were therefore constructed outside the canal where possible. The canal was only closed for the installation of the Kanjel culvert, the lift gate, the steel bridge element and the testing of the various parts.

During this project, BESIX achieved another first: Limmel the game, an educational game for secondary school students. During the game, students take on the role of the various stakeholders in the project. They have to build the new flood barrier together, up against the clock and keeping to a set budget.

The area around the flood barrier is a popular cycling route for schoolchildren and holidaymakers. The new bridge is much safer than the previous one, thanks to the separate car and cycle lanes.

What was the main requirement for the new barrier? For the floodgate to close securely when the area behind the barrier was threatened. The more complicated the mechanism, the more there is to go wrong. So, the subcontractor Agidens Autmation (now BESIX Unitec) has created a system with a minimum of electronics. The hydraulic lifting mechanism is set in motion by the weight of the lift gates themselves. A simple system that also requires little maintenance.