Van Oord wraps up work on Fish Migration River with CSD Biesbosch

Van Oord has completed its work on the Fish Migration River at the Afsluitdijk. This marks an important milestone in the development of this innovative nature restoration project, which contributes to fish migration between the Wadden Sea and Lake IJsselmeer.

The final part of Van Oord’s contribution comprised the completion of the dam separating the Fish Migration River from the IJsselmeer. The construction of this river was commissioned by the Province of Friesland.

The dam, the final component constructed by Van Oord, surrounds the Fish Migration River and protects it from wind, waves and currents. In addition, the dam plays an important role in managing brackish water in the river. Van Oord previously implemented the estuary on the Wadden Sea side and the Lake IJsselmeer side.

Also, as part of the Afsluitdijk dyke reinforcement project carried out by construction consortium Levvel (consisting of BAM, Van Oord, Rebel and Invesis) and commissioned by Rijkswaterstaat, Van Oord was also involved in the implementation of the gap through the Afsluitdijk.

The gap in the Afsluitdijk allows migrating fish from the sea to access the new tidal system, said Van Oord.

For the construction of the dam, Van Oord used raw materials from the immediate area as much as possible.

The sand was extracted from the Lake IJsselmeer with the cutter suction dredger (CSD) Biesbosch. A total of 400,000 cubic meters of sand was extracted from the sea bed right next to the Fish Migration River, eliminating the need to buy and bring in raw materials.

This prevented about 400 shipping movements, or 18,500 truck movements. Some 20,000 tons of quarry stone used for reinforcing the Afsluitdijk was also reused.

The use of area-specific material also contributes to the success of fish migration: The sand and rock have the same smell and taste as the environment, which helps fish with their orientation.

One more step in the construction of the Fish Migration River will follow: the construction of the meandering river, Van Oord added.

The Province of Friesland is expected to start implementation in 2026.