Dating with sheet piling at main waterway Lemmer-Delfzijl

After an intensive process, they concluded that tangible progress is being made. But how exactly?

Integrated exploration

Circular working is increasingly included in environmental impact assessments. Lessons learned from renovation projects are valuable for planning future initiatives. The Main Waterway Lemmer-Delfzijl is being upgraded to accommodate larger inland vessels.

‘At various locations, the waterway is not deep enough, many structures like sheet piling are at the end of their lifespan, and wide ships struggle to pass each other,’ says Gooijert. ‘We are working on a future-proof solution for these challenges.’

The results of this integrated exploration will feed into an implementation program stretching to 2050. Current experiences lay the foundation for a long-term trajectory.

Regional partners

Sustainability has been a focus from the start of the exploration phase. ‘As waterway managers, we define our ambitions in this phase,’ explains Gooijert. The same applies to regional partners like water boards, municipalities, and provinces.

All parties contributed to a joint sustainability session for the Main Waterway Lemmer-Delfzijl, where circularity was chosen as one of five high-priority themes. Rijkswaterstaat has particularly high ambitions for circularity. ‘That’s why we take the lead in working out the circularity ambition.'

'For other high-priority themes, like the energy transition, we take on a facilitating role, leaving the initiative to other partners in the collaboration.’

Reusing materials

Renovating the waterway releases many materials, such as wooden sheet piles. Wood below the waterline is usually in good condition. After trimming, it is suitable for shallow, regional waterways. The contract with the contractor encourages high-grade reuse of these materials.

Dating with sheet piling

‘Under the banner of 'dating with sheet piling,' we explored interest in our sheet piles among Rijkswaterstaat and regional partners,’ says Feike Visser. ‘Conversely, we are also open to used steel sheet piles from other projects.’ Reusing sheet piles in a project of this scale achieves great results in terms of circularity.

Visser adds, ‘We aim for the highest possible reuse value. Together with market partner Nebest, we explored potential applications such as cladding, furniture, and bicycle bridges. However, reuse as sheet piling proved to offer the longest lifespan.’

Documenting specifications

In this contract model, reuse is most effectively managed through the contractor, keeping financial flows within the project. Visser explains, ‘We include an incentive in the contract to store the right amount of wood within short distances from the future project site.’

Meanwhile, it is becoming increasingly clear which types of wood are suitable for reuse. ‘This means specifications must be documented. Not all planks are the same: some are hardwood, some are softwood, and some are coated with tar and therefore unusable.'

'Dimensions such as length, width, and thickness are also crucial. Our key lesson is to document these specifications early, increasing the chances of reuse.’

Tracking your own materials

Gooijert advises engaging experts with the right technical knowledge early on. ‘This helps develop a strategy. If you want to work circularly, you need insight into what happens to your released materials.’