Racing against the storm at an important waterway

The weir at Linne is an important structure for the waterways and inland shipping in the province of Limburg. The weir regulates the water level and water discharge in the Meuse (or Maas in Dutch) river. On February 10, 2020, storm Ciara hit the Netherlands. Two barges that had broken loose from their moorings collided with the weir and damaged at least four steel trestles (uprights that support the weir partitions). Mourik Infra was already responsible for the maintenance of the weir, in a consortium with SWARCO. Together with Rijkswaterstaat, we immediately formed a crisis team to take measures to prevent flooding and keep people and property safe. The first priority: ensure sufficient water control along this important waterway.

First priority: reducing the risk of flooding

We first built a temporary emergency dam with quarry stone and set up a real-time monitoring system to ensure safety. On the other side of the weir we poured underwater concrete with quarry stones so that the water bed could absorb the force of the excess water that needed to be drained. This way, we created safe conditions and the opportunity to assess the damage and draw up a plan for the repairs. Besides the four trestles, a number of bridge components were also visibly damaged. The weir was already scheduled for a complete overhaul and so Rijkswaterstaat took this opportunity to have the refurbishment carried out sooner than originally planned. But that posed a new challenge: the weir had to be completely up and running again before the new high water season in November.

Refurbishing weirs and locks is always a unique task

The fight against the water also became a race against time, which presented the inevitable technical challenges. Weirs and locks must of course meet current standards and last at least twenty years without any problems. Though we have extensive experience in design and engineering in this area, no two weirs are identical. This time too, there were special challenges, such as needing to reinforce the back pivots of the trestles and installing several new bridge components as well as a 65-metric-ton winch structure connecting all the trestles. Now, at the touch of a button, the partitions can be lifted out of the water and safely stowed all at the same time. Constructing the trestles was in itself a beautiful piece of engineering, with critical dimensions and various materials that had to be welded together. This we did in house, at our site in Echt. The final triumph was a new weir crane that can move over the weir to lift the partitions out of the water and stow them.

Two years: that’s how long a project of this scope would normally take. We got it done in less than half, and this despite all the Covid-19 measures and challenges we were facing at the time. This is thanks to the terrific collaboration between all the parties, with our client Rijkswaterstaat leading the way. No defined contractual requirements but rather ongoing coordination between the parties, rapid decision-making, working based on trust and collaborating based on craftsmanship. With this approach we were able to meet the extremely tight schedule and restore water control measures that keep this important waterway and its environments safe.