Aduarderzijlen lock complex restored to its former glory

Aduarderzijlen lock complex reopened

With the firing of a cannon, Bert Wiersema (member of the executive committee of the Noorderzijlvest Water Authority), Bé Schollema (alderman of the municipality of Westerkwartier), and Karin Dekker (deputy of the province of Groningen) gave the starting signal for the reopening of 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 board 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-meter-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 using traditional methods. To this end, the locks were temporarily drained. The old windworks were also restored and the steel fittings of the locks were renovated and preserved. Repair work was also carried out on the box sluice. The foundation stone of this box sluice, which is clearly visible from the road, was also restored to its former glory.  

Creating work with 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 facilities were enhanced and the experience improved. By combining the work, recreational facilities were integrated into the landscape in line with 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 that the strategically located sluices and surrounding area played 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 rear and a terrace next to the former warehouse, which has been integrated into the landscape in combination with greenery. 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.

Preservation of 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 mounds in the landscape, show how the people of Groningen have pioneered over the centuries to overcome the influence of that sea. By preserving the sluices, we are contributing to passing on this landscape to future generations. In addition, the preservation of this heritage is not separate from its surroundings and is inextricably linked to them. 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 sluice in the dike was constructed to discharge excess water into the Reitdiep. This was connected to the sea, where the tides played a role. The western sluice 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 sluice. In 1867, the eastern sluice was built to improve water drainage. After the closure of the Reitdiep near Zoutkamp in 1877, the sluices were only closed when storm surges threatened. With the closure of the Lauwerszee in 1969, they lost this function as well. The sluices became a hydraulic engineering monument.

Financing

The work on the lock complex and surrounding area was carried out on behalf of the 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 Program Groningen in collaboration with the province of Groningen (€600,000) and the municipality of Westerkwartier (€300,000) for the economic and recreational enhancement of this location between the city and the mudflats. TenneT contributed €300,000 from a good landscape integration of the new 380kV high-voltage connection.