In the first DFSI Magazine, the concept of sustainability in relation to dredging projects was explained. How to integrate this concept in project design is the focus of this article, adapted from the third chapter of Dredging for Sustainable Infrastructure (2018), and provides the theme for this issue.

AquaForest is a demonstration project led by Jan De Nul showcasing a green-grey approach, where dredged sediments are being reused to create 50 hectares of mangrove habitat in the Guayas Delta, Ecuador. The project aimed to advance knowledge on the conceptual design and eco-engineering approaches of mangrove habitats, while strengthening local engagement and generating diversified income opportunities for local communities. A new mangrove island was built in the end of 2024 and is currently being monitored to quantify the provision of ecosystem services over time with the aim of future upscaling of this type of nature-based solutions.

While essential to coastal development and maritime industries, dredging and marine construction activities can unintentionally disrupt marine ecosystems. At Van Oord, we aim to deliver solutions for marine infrastructural developments that protect and enhance habitats and biodiversity. Over the past few years, we have explored how nature-inclusive designs can transform traditional marine infrastructure into ecosystem-supporting assets. The reintroduction of the European flat oyster to the North Sea is a key example.

A fixed and direct transport connection between Scandinavia and Central Europe has been an enduring vision for many decades. This vision is now about to be realised with the construction of the Fehmarnbelt Fixed Link – an immersed tunnel that will cross the approximately 18-kilometre-wide Fehmarnbelt sea strait between Rødbyhavn in Denmark and Puttgarden in Germany.

Alex Hekman, NL2120 and René Vrugt, Ministry of Infrastructure and Water Management discuss the necessity for a complete approach aimed at sustainable and climate-proof use of land and water systems.

Estuarine tidal wetlands offer vital ecosystem services, including flood protection, erosion control and water purification. However, these estuarine ecosystems actually face significant pressures caused by both human activities and natural forces, leading to habitat and ecosystem degradation and loss. The Bankbusters project adressess these issues by reusing soft dredged sediments to restore tidal marshes and mudflats as natural riverbank systems. As such, this initiative promotes biodiversity, enhances flood resilience and supports sustainable economic growth through innovative, eco-friendly and resilient solutions in the Scheldt estuary.

Adapted from the second chapter of Dredging for Sustainable Infrastructure (2018), this article forms the foundation for this first issue and presents the concept of sustainability in relation to dredging projects. It describes the approaches and practices that are key to creating more sustainable solutions and infrastructure – a modern way of thinking about dredging.

In early 2018, the Government of the Republic of Benin awarded Jan De Nul a design and build contract to protect a 5-kilometre-long stretch of coastline near the town of Avlékété. The project fits into the government’s plan to turn the local coastal zone, which includes a lagoon, sandspit and beaches, into tourist hotspots. Yet the persistent oceanic swell and chronic erosion required an intervention. This is the perfect starting point for a nature- based structure that offers multiple ecosystem services. Its long-term effectiveness, however, hinges on the support of its end users. Stakeholder engagement was therefore central to the project.

Sustainability, innovation and collaboration are key to successfully facing today’s global challenges of grid congestion and climate change. To combat these challenges, the Delta21 concept has been developed in the Netherlands. Located in the mouth of the Haringvliet estuary in the Dutch Delta, the project combines energy storage, flood protection and the restoration of nature. The concept could be elaborated upon and applied worldwide, inspiring governments, public bodies knowledge centres and developers to face climate change and move away from fossil fuels.

Lara Muller (Invest International) and Pieter van Eijk (Wetlands International), discuss the role investors and NGOs can play in driving demand for nature-based solutions.

The coastline of Togo and Benin moves between 1 and, in some places, even 10 metres every year. Land inwards, of course. Climate change is the cause: sea level rise leads to coastal erosion and that poses a direct threat to economic activities and life on the West African coast. “The inhabitants of this region depend primarily on fishing and tourism for their incomes and livelihoods. Thanks to this coastal protection project, they can benefit from the opportunities the beach and coastal environment offer them, now and in the future,” says Boskalis regional manager Pieter Boer.

Guest editor Polite Laboyrie International Director, Witteveen+Bos.

Green solutions in ports, waterways and coastal projects have increasingly become available thanks to many years of research and pioneering efforts in practice. These sustainable solutions have shown to be good alternatives for classic solutions, but application is far from mainstream yet. One of the major hurdles is the lack of access of private capital to finance these kinds of solutions despite the strong interest of capital markets in green infrastructure opportunities. Identifying the hurdles and paving a way forward to overcome these hurdles could therefore help to increase the uptake of those green solutions.