Aduarderzijlen lock complex restored to its former glory

Aduarderzijlen lock complex reopened

With a cannon shot, Bert Wiersema (executive board member of Noorderzijlvest Water Authority), Bé Schollema (councillor Westerkwartier Council), and Karin Dekker (provincial executive member of the Province of Groningen) marked the start of reopening the cultural-historical lock complex. 

Repair bridges and locks

The lock complex was in need of a major refurbishment in order to preserve this water heritage as a cultural-historical object. In 2022, the water authority gave the go-ahead for the restoration of both locks and the accompanying bridges. Both bridge decks were replaced and the original railings were repaired. A new foundation was also constructed. Twenty-metre-long piles were driven into the ground to relieve the pressure on the lock walls. Subsequently, the locks were renovated in 2023. The joints and masonry were renovated with traditional methods. The locks were drained temporarily to make this happen. The old gears were also restored and the steel fittings of the locks were renovated and preserved. Repair work was also carried out on the culvert sluice. The foundation stone of this culvert sluice, which is clearly visible from the road, was also restored to its former glory.  

Combining work 

By taking a broad, integrated view, the restoration of the lock complex also offered opportunities. In consultation with the relevant authorities and the residents of Aduarderzijl, the landscape and recreational opportunities were enhanced and the experience improved. By combining the work, recreational facilities were integrated into the landscape after the work on the locks. Walking paths, trees, hedges, and shrubs were planted, and an educational mini-fort was built. Together with the restored cannons, they serve as a reminder of the role played by the strategically located sluices and surrounding area during the Eighty Years' War. In addition, the familiar white fencing has been renewed and has taken its place along the characteristic curve of the road. A parking facility has also been constructed at the back and a terrace next to the former lockkeeper's house, which has been integrated into the landscape. Various jetties have been installed for recreational boating. Additional investments have been made in nature-friendly banks along the Aduarderdiep to improve water quality. The project also includes the construction of a new jetty at Schifpot and parking facilities with an information board near the bridge at Steentil.

Preserving cultural and historical heritage

The Aduarderzijlen are part of the cultural and historical heritage of Noorderzijlvest. The Reitdiep shows how the Wadden Sea originally penetrated deep into the land in Groningen. The hydraulic-engineering works (the Aduarderzijl, the locks, and the bridges), together with the dwelling mounds the landscape, show how the people of Groningen pioneered to overcome the influence of that sea over the centuries. By preserving the locks, we contribute to passing on this landscape to future generations. In addition, preserving this heritage is not separate from its surroundings as it is inextricably linked. Investing in the preservation of these objects also provides the opportunity to incorporate the wishes of the local community for good landscape integration into the restoration work.

A special showpiece

Around 1400, the Aduarderdiep was dug and the first locks was built in the dyke to discharge excess water into the Reitdiep. This was connected to the sea, where the tides played a role. The western lock was built in 1706, after a storm surge had washed away its wooden predecessor. When the doors were open at low tide to discharge water, ships could also pass through the locks. In 1867, the eastern lock was built to improve water drainage. After the closure of the Reitdiep near Zoutkamp in 1877, the locks were only closed when storm surges threatened. With the closure of lake Lauwerszee in 1969, they lost this function as well. The sluices became a hydraulic-engineering monument.

Financing

The work on the lock complex and the surrounding area was carried out on behalf of Noorderzijlvest Water Authority by contractors Oosterhof-Holman and Kramer Metslawier. The water authority invested €3,000,000 in the renovation of the Aduarderzijlen lock complex and the construction of nature-friendly banks. The project was made possible in part by contributions from the National Programme Groningen in collaboration with the Provincial Executive of Groningen (€600,000) and Westerkwartier Council (€300,000) to strengthen the economic and recreational potential of this area between the city and the mudflats. TenneT contributed €300,000 to ensure the new 380 kV high-voltage transmission line is integrated seamlessly into the landscape.