Tidal park Keilehaven takes shape

New nature in former industrial port

The Municipality of Rotterdam and the Port Authority are developing the Merwe-Vierhavens (M4H) area into an innovative live/work environment with a mix of working, living, culture, catering, sports and education. The first step in that development is the transformation of a straightforward pier into a tidal park with space for recreation and nature. Hydraulic engineers Van den Herik of Sliedrecht and De Vries of Werkendam are jointly carrying out the work.

A tidal park is being turned from the old dock on the north bank of the Meuse River. The tidal park was designed by De Urbanisten in collaboration with ARK Rewilding Nederland. 

The harbor basin will be transformed from a stony waterfront plain to new nature where people can also recreate. A tidal park provides a better living environment in the region, and makes the river ecologically valuable. The ebb and flow makes the park look different at any time of day. This is good for all residents and visitors to the region, for nature, for a sustainable port and for a future-proof region.

At tidal parks you see the water - due to the open connection to the sea - rise and fall about a meter and a half twice a day. Tidal parks and tidal banks provide cooling in hot summers. The slowly sloping banks provide wave breakage during high tides.

Plants that thrive on the boundary between fresh and salt water will soon grow there, such as spindle buttercup and greater water plantain. It also attracts many, sometimes unusual birds, such as spoonbills, avocets and common terns. Fish such as eels, salmon and sticklebacks find rest and food here.

Level differences

Gerco Grootenboer is supervising the construction of the park in the Keilehaven on behalf of Van den Herik. "The tidal park will soon consist of nine tidal terraces that will increase in size and scale from the head of the Keilehaven towards the estuary," he explains. "To do this, we first dredged the harbor, removed the partially contaminated soil, constructed an underwater dam and partially filled the harbor basin with 10 thousand cubic meters of sand brought in by water, so we didn't have to drive hundreds of trucks through the city. Meanwhile, with a number of pontoons and excavators, we started laying out the terraces." 

To that end, steel sheet pile walls will be installed to create level differences that will flood or dry out during the tide. The sheet pile walls will be hidden from view by gabions filled with recycled pavers and paving stones. "Because the water occasionally reaches those baskets, if all goes well, nature will also develop there," Gerco explains. "Good for biodiversity." 

Sweet and salty

Ruud van Rooijen is project manager from the municipality of Rotterdam. "The new tidal nature attracts special plants, fish and birds that live on the border of fresh and salt water through the action of ebb and flow," he explains. "And the place will soon offer Rotterdammers the chance to walk and picnic along the green banks of the New Maas. In that way, if all goes well, this place will become the trigger for the entire M4H area." 

In addition to the used street clinkers and paving stones incorporated in the gabions, Van den Herik and De Vries also try to reuse other materials in close cooperation with Rotterdam and the Port Authority. Ruud often knows exactly if soil, sheet pile walls, concrete fences or ballast material is released during other projects in Rotterdam. "For example, for the attenuation we partly used ballast material from old streetcar rails, among other things. And in the promenade we will soon be using old quay boulders that we have taken away from somewhere else."    

Existing trees

"It is a unique and challenging project where we can use our creativity to make the project as circular as possible," says Gerco. "For example, for the construction of the park we are also still looking for two large existing trees that we will put underwater. With these we will create new underwater nature and a special ecosystem for fish. We are trying to find those trees in one of our other projects or elsewhere in Rotterdam. For example, specimens that were recently blown down during a storm. That way they will get a nice new function here." 

Van den Herik and De Vries are working on the construction of the tidal park until the end of the year. When the excavators have left and nature is given a chance to populate the former industrial site, next year there should be a beautiful park that marks the beginning of the development of a completely new city district on the water of the Meuse.