Lauwersoog dyke passage opened: new tidal area in De Marnewaard

Initiators on the realization of the tidal area 

Leo Wenneger, Provincial Executive Member for Groningen:“Thanks to the tidal culvert, 70 hectares of land inside the dykes in the Marnewaard are once again subject to the influence of the tides. This is unique in its design and scope, as it creates a richer living environment for countless plant and animal species from the Wadden Sea. It clearly demonstrates how we in Groningen are working to create a coastal zone that is in harmony with the dynamics of the Wadden Sea region. The end result will be a broader coastal zone that is ready for the future (water safety) and offers space for unique nature, agriculture, recreation, and quality of life.”

Annette van Velde, director of the Noorderzijlvest Water Authority: “It's wonderful that we can also use the necessary dyke reinforcement for water safety to strengthen nature. Together with market parties, we are building the most sustainable dyke in the Netherlands, with significantly lower emissions and smart (re)use of raw materials. It's great that we can also include ecological projects in this. A tidal culvert may sound like a hole in the dike, but it is actually a well-thought-out and safe construction designed to allow controlled water flow without compromising water safety."

Mieke Langedijk, director of Rijkswaterstaat North Netherlands: " On the border between the Wadden Sea and Lauwersmeer, we combine protection against the water with space for nature development. Together with all stakeholders, we have invested in measures that help improve the ecological water quality of the Wadden Sea. The arrival of the tidal culvert is of great importance in this regard. As are the construction of artificial reefs and tidal pools at the foot of the dike and the salt marsh expansion at the Westpolder. These measures make the transition between the mudflats and the dike more natural. This is good for birds, fish, and underwater nature."

Tidal area in the Marnewaard

The tidal culvert opens up the new 70-hectare tidal area in De Marnewaard behind the Lauwersmeer dike. With the opening of the culvert and the influx of seawater, a tidal area will be created here. This will increase biodiversity and improve water quality. It is expected that new habitats will be created for species such as samphire, sticklebacks, smelt, avocets, and spoonbills.

The culvert in the sea dike, which is approximately 80 meters long and 2 meters wide, allows seawater to flow in and out of the tidal area in a controlled manner and within water level limits.  For water safety, the tidal culvert has two sluice gates that can close the passage. This allows us to determine the water level in the tidal area. The location of the new tidal area is the old salt marsh area of the Marnewaard military training ground. This part of the site is not used for military activities.

Cooperation and financing 

The nature projects are an initiative of the Province of Groningen, the Noorderzijlvest Water Authority, and Rijkswaterstaat, in collaboration with Stichting Het Groninger Landschap (also on behalf of nature organizations Natuurmonumenten, Staatsbosbeheer, and Natuur en Milieufederatie Groningen). The total cost of the projects is €32 million. This amount is being financed by the Programmatic Approach to Large Water Bodies (PAGW) of the Ministries of Infrastructure and Water Management and Agriculture, Nature and Food Quality, the Wadden Fund, the Province of Groningen, and funds from the NextgenerationEU program.