New Waterworks Zoutkamp

To deal with the consequences of climate change until 2050, greater drainage capacity is needed to protect the historic Groningen fishing village of Zoutkamp and its surroundings from high water. Noorderzijlvest Water Board, the municipality of Het Hogeland and the province of Groningen saw coupling opportunities and are therefore pulling together in the Nieuwe Waterwerken Zoutkamp project to not only increase water safety but also to give an immediate boost to the quality of life, traffic safety and tourism in Zoutkamp and the surrounding area.

The initiative for this unique project comes from the water board. "We see a number of things coming at us through 2050 that affect our management area and for which we need to take measures to keep dry feet," says Mark Pietersen, project manager at Noorderzijlvest Water Board. "The west side of the city of Groningen is actually the drainage basin's drain. The water that falls on the Drents Plateau (the area between the cities of Assen and Groningen, ed.) all flows to the west side of the city of Groningen and then has to flow onto the Hogeland, the region north of the city of Groningen. The necessary water storage areas have already been created for this purpose. But that alone is not enough. On the north side of the city extra drainage capacity is needed to drain water in the direction of the Lauwersmeer. Excess surface water is temporarily stored there and, when the tide is favourable, discharged into the Wadden Sea via the R.J. Cleveringsluizen. To this end, in 2022 we have already increased the discharge capacity of Schaphalsterzijl pumping station by 420 m3 per minute and now the H.D. Louwes pumping station in Zoutkamp must also be increased by an additional 600 m3 per minute."

However, the task in Zoutkamp is even greater, because in order to keep dry feet, the regional dikes would have to be raised by 60 to 80 centimeters. Since these run right through the village, the entire village would have to be raised. That was not exactly desirable. Therefore, the water board came up with an alternative, in which the former sea dike played a leading role. After all, Zoutkamp used to be located by the sea. When in 1953 as a result of the flood disaster the Lauwerszee was dammed up in 1969, it transformed into a lake. Since then, the Hunsingo sluice in the former sea dike no longer has a sea defence function. "In the exploratory phase in 2019, we weighed up both variants: either enlarge the current pumping station and raise the embankments through the village or move the entire package up to the sea dike, including the construction of a new pumping station and the restoration of the Hunsingo lock, which has been crowned a national monument," Pietersen says. "In the end, the latter option was chosen and from 2019 we have been busy arranging financial coverage and looking for linkage opportunities to complete the business case."

In order to achieve a thorough and well-considered design, it was decided to involve the market early in the project and not wait until the specifications were ready. "So we put a 2-phase contract on the market. Two contractors bid for it and then we went with Strukton for the first phase. The assignment was to come up with a feasible and surprise-free DO. That became final in December 2022, after which the General Board of the Noorderzijlvest Water Board approved the implementation credit for the entire project in February 2023." Marcel Kampman, project manager at Strukton: "Ultimately, we arrived at a design in which we are building a new pumping station with the intended capacity of 1,600 m3 per minute next to the monumental Hunsingo sluice built in 1859. The lock will also be tackled. We are going to restore it and convert it to a lock, so that shipping remains possible even when the pumping station is in operation. That is not the case now." 

Strukton started outdoor construction in May 2023. "We started by creating a construction pit of 100 by 20 meters for the substructure of the pumping station. In this, 407 combi piles with a precast core and grout casing were installed," says Kampman. "Then the pit was excavated to about 8.5 meters deep and we poured an underwater concrete floor 1 meter thick. The tub was drained and has been fantastically dry ever since." Meanwhile, the structural floor has been poured and Strukton is in the process of making the outer and intermediate walls for the three power shafts. "Around September of this year, the shell construction of the pumping station will be finished and we will begin the restoration of the Hunsingo lock. At that time, the Hunsingo Canal will be completely dammed with a construction pit. The old pumping station H.D. Louwes must still be able to pump the water to the Lauwersmeer next winter season, and that will be done via a bypass through the flow chambers of the new pumping station. Thus, we do not need a temporary pumping installation."

The Hunsingo lock is an old sea lock. When the H.D. Louwes pumping station is running, no shipping is possible. "That will soon be a thing of the past," Pietersen assures. "For the restoration and design of the new lock, we were advised in part by the National Cultural Heritage Agency and a restoration architect. The advice was not to make the mistake of making the new part of the lock, which will literally be 'stuck' to it, look old. In this way, the timelines will soon be nicely visible. Old remains old and new becomes new. The wooden doors will also return to the flood lock, although they will be operated electromechanically, while the new section will have steel lock doors that will be operated hydraulically. A nice combination of techniques. The lock will also not be completely dry, to avoid damaging the lock's structure."

By October 2025, the entire structural work and most of the completion of the pumping station and lock are scheduled to be completed. This will be followed by a period of adjustment and tuning of the systems. Final acceptance will follow in March 2026. At the same time, Strukton is also carrying out five coupling opportunities for the municipality. A deliberate choice, according to Kampman, so that the local community can see that one party is working on the project and that they can contact one desk if they have any questions. Besides water safety, traffic safety will also be improved, tourist and recreational opportunities around the Lauwersmeer will be expanded and boating recreation towards the Hogeland and the city of Groningen will be enhanced. Pietersen concludes, "After completion, we are again challenging the market to dismantle the old H.D. Louwes pumping station in a sustainable, responsible and innovative way."

New Waterworks Zoutkamp is funded in part by the National Program Groningen, the Wadden Fund, the Heritage Deal and the Committee on Subsidence.