Innovative solutions to keep the Netherlands safe from flooding
Published on: February 28, 2025
The Netherlands, renowned for its Delta Works that protect vast areas below sea level, faces a new and pressing challenge—preparing for a future where sea levels could rise by up to five metres by the year 2200. With climate change driving this increase, the country must explore innovative ways to safeguard its low-lying regions. A government-backed study, Room for Sea-Level Rise, examined whether the Netherlands could remain liveable under such extreme conditions. The conclusion is that it’s possible to keep the country safe from flooding, but only through bold interventions, significant investments and long-term planning.
Alex Hekman, Business Director Water at Sweco in the Netherlands, and a key expert and one of the initiators of the study, shares insights into how this ambitious research was conducted and what it means for the future of the Dutch Delta Works.
Understanding the threat of rising seas
Sea-level rise is no longer a distant concern—it is happening now. According to the study, by the year 2100, sea levels could rise between 0.28 and 1.88 metres, depending on global CO₂ emissions. If Antarctic land ice destabilises, sea levels could exceed two metres by 2100 and five metres by 2200.
Such an increase would have enormous consequences, including coastal erosion, salt intrusion, reduced river discharge capacity and increased flood risks. This threatens the economic heart of the Netherlands—the Randstad, home to cities like Amsterdam, Rotterdam, The Hague and Utrecht.
Despite these risks, Hekman was alarmed to discover that major infrastructure projects had failed to account for rising sea levels.
“A few years ago, I saw that the five largest investment programmes in the Netherlands barely considered the effects of sea-level rise,” he explains. “That’s why we wrote the whitepaper ‘Ruimte voor de toekomst’ (Room for the future) where we calculated the costs and spatial demands of these projects and how they would be affected by rising water.”
His findings gained the attention of policymakers, leading to the launch of a nationwide study to investigate possible solutions.
Three strategies to protect the Netherlands
The research team, consisting of engineers, policymakers, scientists, landscape architects, contractors and economists, examined three main strategies:
Protect – Reinforcing flood defences such as dikes, storm surge barriers and pumping stations.
Advance – Constructing a massive offshore coastal reservoir to store and regulate water, reducing the need for extreme dike reinforcements.
Accommodate – Adjusting land use to higher water levels, with flood-proof buildings, floating infrastructure and changes to agriculture.
Hekman was initially tasked with researching the Advance strategy but quickly realised the need for broad collaboration.
“From my work to develop an integrated coastal strategy to protect Jakarta from flooding, I learned that a challenge this complex requires input from the entire water sector,” he says. “We needed engineers, water managers, economists, ecologists and policymakers working together as a consortium.”
Building a nationwide collaboration
One of the biggest challenges was securing funding. Initially, only €50,000 was allocated for the study. However, Hekman and his colleagues successfully raised half a million euros by rallying support from the Dutch Ministry of Infrastructure and Water Management, Deltares and the Topsector Water & Maritiem.
“When we secured the additional funding, an interesting dynamic emerged,” Hekman recalls. “We realised that focusing solely on the Advance solution would create an imbalance. So, the government decided to also fund two additional consortia for the Protect and Accommodate strategies. That challenge landed on my plate.”
Within a month, Hekman and his team built three independent research consortia—one for each strategy.
“I called two colleagues with authority in the sector—one from Arcadis and one from Witteveen+Bos—and asked if they would help build and lead the three consortia with me,” he explains. “Without competition, just trust. In one month, we secured three times half a million euros and got to work.”
How each strategy would work
The Protect strategy involves raising and reinforcing dikes, increasing pumping capacity and maintaining open estuaries with storm surge barriers. However, this would require massive investments, with costs ranging from €100 to €200 billion.
The Advance strategy proposes constructing a 60-kilometre-long second coastline up to 12 kilometres offshore, creating a reservoir to store river water before pumping it out to sea. This would reduce the need for extreme dike reinforcements in complex urban areas and help control salinisation. However, it would also destroy valuable coastal ecosystems.
The Accommodate strategy focuses on allowing water to take up more space, shifting to flood-proof buildings and floating infrastructure. While this approach is sustainable in some areas, it is hardly viable for the highly populated Randstad, which would still require protective measures.
Hekman admits his perception of the Advance strategy changed throughout the study.
“When we started, I was convinced that the offshore coastal reservoir idea wouldn’t work,” he says. “Before we started, there were already designs for a 200-kilometre coastal lake stretching from Walcheren in the southwest to Den Helder in the northwest. I thought, ‘I’m leading the consortium for the one solution strategy that definitely won’t happen.’ But with the expertise of so many specialists, we shaped it into a feasible strategy. That’s why my first slide in every presentation was titled: ‘From megalomaniac idea to realistic perspective.’”
Moving forward: No-regret measures and nature-based solutions
While the study confirms that the Netherlands can remain safe even with a five-metre sea-level rise, it also highlights the need for immediate action. Some no-regret measures—reinforcing Randstad’s flood defences, adapting agriculture to saline conditions and reserving space for future water infrastructure—must begin now.
The study also shows that closing off the Dutch delta with new construction works will have large negative ecological impacts. Hekman believes that Nature-Based Solutions should therefore play a larger role in future strategies.
“Ninety years after the Afsluitdijk dam was built, we’re still making adjustments to restore ecological balance,” he points out. “The same goes for the Delta Works. We need to rethink our approach and put nature at the centre of our solutions from the start.”
Constructions at the Afsluitdijk, a famous dyke in the North of Holland, seperating the Ijssel lake from the Wadden Sea, The Netherlands. Credit: claffra/Getty Images
Hekman consequently initiated a new consortium to explore how wetlands, dune systems and other nature-based solutions can help mitigate sea-level rise. Results are expected to be published this spring.
“We’ve already arrived at very interesting results,” Hekman reveals. “Nature-Based Solutions keep the Netherlands not only safe from flooding, they use natural sedimentation processes to allow the land to grow with the rising sea level, while at the same time preserving the coastal ecosystem. I truly believe that if we integrate natural processes into our sea-level rise strategies, we can make the Netherlands both safer and healthier.”
A future of resilience and innovation
The Netherlands has long been a leader in water management, and this study confirms that the country can remain liveable even in the face of extreme sea-level rise. However, this will require significant investments, long-term planning and a willingness to embrace both engineered and natural solutions.
Hekman remains optimistic that with collaboration and innovation, the Netherlands can continue to thrive.
“We’ve shown that even with extreme sea-level rise, we have options,” he says. “The key is acting now to ensure those options remain viable in the future.”
