Rising sea levels are a global challenge for coastal areas. Traditionally, the solution has been concrete sea walls, but are there more natural solutions?
Researchers at Ghent University are working with dredging and marine engineering company DEME to explore practical ways of protecting our coastlines using nature-based approaches. This is being done through the Chair “Nature-based Solutions for Resilient Coasts”.
Concrete sea walls don’t solve the climate problem
Dieter Rabaut (DEME) starts off: " A staggering 40% of the world's population lives within 100 kilometres of a coast. Due to climate change, we’re seeing an increasing demand for coastal protection: how can we safeguard the people living there against rising sea levels?”
“Constructing concrete sea walls releases large amounts of CO₂, primarily due to cement production. If we keep covering our coastlines in concrete, we might be tackling one problem—coastal protection—but we’re exacerbating another: climate change. By using Nature-based Solutions, we can address both issues in a sustainable way.”
Merel Kroeders (DEME) adds: “We’re investigating whether we can replace traditional concrete or stone sea defenses with more natural systems, like gently sloping beaches with dunes and vegetation, or salt marshes and mudflats that naturally protect riverbanks. Nature can offer fantastic solutions: for instance, mudflats and salt marshes not only absorb wave energy, but also serve as carbon storage.”
Rolling out seagrass mats
Ghent University and DEME are also looking into new sustainable ways to protect our coasts. Before joining the Faculty of Bioscience Engineering, Alexia Semeraro studied which plants and animals could naturally protect our shores. Her research took place in the lab, but also at sea – which proved much more challenging.
Alexia: "For example, we placed seaweed in the sea and looked at whether it could develop into a full-fledged biogenic reef. Then we examined whether those reefs provided adequate coastal protection – did they help stabilize the coast and reduce wave energy?”
“The seaweed struggled in our waters, but one particular type of seagrass performed quite well as a coastal buffer. In Portugal, we conducted research, rolling out mats with seeds of that grass in places where coastal protection is needed."
Worms and mussels to the rescue
Alexia: “In a different project, we’re exploring whether the sand mason worm can help protect our coastlines. These tiny creatures are native to the North Sea. We use specific substrates to attract them. If they like the environment and decide to stay, they form reefs with up to five hundred worms per square metre. Working with these worms was quite exciting: they’re animals, not plants – they have a mind of their own!” (laughs). A PhD student is now continuing this research.”
Merelintroduces another alternative: “The ‘Musselshaker’ is an innovative way of creating a reef. We place a metal structure on the seabed using an anchor. Mussels grow on the structure until they’re fully grown, then fall off and settle around the anchor, creating a biogenic reef. We're currently investigating how such a reef impacts coastal protection.”
Belief in nature-based solutions for the future
With their research results, Ghent University and DEME aim to create a practical guide. This guide will help engineers design nature-based solutions and support coastal municipalities and other authorities in making informed decisions on coastal protection.
Dieter: “We firmly believe that our nature-based solutions are not only technically sound, but often better and more sustainable than traditional methods. The Low Countries have always been pioneers in hydraulic engineering. At DEME, we want to continue playing a leading role – not only as an economic force but also as a socially relevant company.”
Professor and chair holder Margriet Drouillon adds: “In parallel, we are launching new research that combines nature-based solutions with insights from the financial world. This will allow us to better assess the value of these solutions – not just financially, but also in terms of societal and ecological benefits. The findings will feed into the practical guide.”
“Climate change is progressing rapidly, and research sometimes struggles to keep up with the urgent need for action. Thanks to our practical guide, nature-based solutions can be implemented more quickly. Ghent University and DEME are in constant dialogue, enabling discoveries made in the lab to be tested and refined at sea or on a large scale. It’s a challenge – but it works.”
Merel: “No one knows exactly what climate change will bring. Compared to rigid concrete or stone dykes, nature-based solutions are far more adaptable and better equipped to handle unexpected developments. I sincerely hope that these solutions will become the standard in the future. Given today’s climate crisis, nature-based solutions should no longer be Plan B – they must be Plan A.”
Alexia agrees: “You have to believe in them to make them work. And we do – that’s why we call ourselves ‘the believers’.” (laughs)
Who is who (left to right)
Dieter Rabaut works at DEME and is Head of the Design and Engineering Department for Offshore activities. He enjoys modern and contemporary art, and his favourite spot in Ghent is the Drongenhof Chapel in the Patershol district.
Merel Kroeders works at DEME as a design lead in the engineering department. She loves Japanese ramen and enjoys travelling the world in search of new cultures and flavours.
Margriet Drouillon is the chairholder of the Chair on Nature-based Solutions for Resilient Coasts, with Ghent University professor Colin Janssen as its promoter. The chair is one of the achievements of the IOF (Industrial Research Fund) consortium BLUEGent. Margriet is a fashion enthusiast and can often be found at the Ghent Winter Circus on weekends.
Alexia Semeraro works at the Faculty of Bioscience Engineering and conducts research on nature-based solutions for coastal resilience. She also enjoys diving and hiking in nature, and loves having an aperitif by the Saint Michael’s Bridge in Ghent.
About the Chair “Nature-based Solutions for Resilient Coasts”
DEME is an international company specializing in dredging and marine engineering, with a strong focus on innovative and sustainable solutions. Through this chair with Ghent University, they hope to contribute significantly to the development and implementation of nature-based solutions for coastal areas—solutions that not only protect against rising sea levels but also help restore natural ecosystems.
Want to learn more about Ghent University chairs?
A chair is a partnership in which a company, social organization or private individual commits to funding thematic scientific research or education at Ghent University over a longer period. Interested in setting up a chair yourself? Get in touch with Liesbeth Plovie (+32 9 264 33 87).
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