Storm surges are one of the main natural threats in the North Sea region. Today, coastal ports are most at risk of flooding in case of heavy stormy weather. To protect the coast and hinterland from heavy storms, the Flemish Government approved the Masterplan for Coastal Safety in 2011. This plan includes the building of a storm flood barrier at the mouth of the river Yser in Nieuwpoort. After in-depth studies, a horizontal sector gate with a clearance width of 38 meters was chosen.

Rotating steel barriers

The movable steel barrier is a construction that rotates around a horizontal axis. When parked, the barrier is sunk in a concrete sill at the bottom of the river Yser. The steel barrier rotates between two cast steel shafts which are anchored in concrete abutments connected to the banks of the Yser.

Maintenance of the barriers

For maintenance purposes, the barrier can be rotated 180 degrees into the horizontal maintenance position. Alongside the sector gates, large lateral ducts (bypass sewers) will be built in the abutments. These can handle additional flows, keeping the current velocity at spring tide below 3 knots and limiting the impact for recreational boating.

Apart from the building pits, other steel combined walls, sheet pile walls and tubes were installed for the quay walls at both embankments, current conducting walls, a construction pit for the bypass sewers, an undercurrent screen, guiding walls and dolphins.

The project started in February 2018 and will be completed in 2025.