The Netherlands versus the sea: The race to hold back rising waters
Note: This article is based on a piece originally published on CNN Climate and has been adapted for the Dutch Water Sector website.
The Netherlands has spent decades building and perfecting one of the most sophisticated water-defence systems in the world. With one quarter of the country below sea level, water remains an ever-present threat, and defending against it, from the rising levels of the North Sea to overflowing rivers, is central to the country's survival. But as the rate of sea-level rise continues to increase and extreme weather becomes more frequent, experts say the systems that have kept the country safe for decades will struggle to keep pace without significant upgrades.
"We live in a bathtub and the bathtub will fill up," said Co Verdaas, Commissioner of the national water-defence programme, the Delta Programme. "And because we fully trusted centuries of technical water management, we forgot how vulnerable we are," he told CNN. "We are literally also reaching the limits of what we can do with technical management."
Below sea level
A report published in March 2026, which analysed 385 peer-reviewed studies, found that current global coastal sea levels have been underestimated and are, on average, around 1 foot higher than previously assumed. In some places, such as Southeast Asia and parts of the Pacific - sea levels may be up to 3 feet higher. The Netherlands' extensive system of storm-surge barriers, known as the Delta Works, has protected the country for decades. Spanning roughly 1,000 kilometres (621 miles), the Delta Works consists of more than a dozen major components, including dams, dykes, levees, sluices and pumps. Completed in 1997, it was built to hold back the sea and is widely regarded as a global model of how modern infrastructure can protect coastal areas.
Construction began after the devastating North Sea Flood of 1953, which left more than 2,000 people dead along the coasts of the Netherlands, Belgium and the United Kingdom. The disaster, the worst in the Netherlands since the Middle Ages, led to the development of a comprehensive system aimed at preventing future flooding. "If you look back at our history, we had this strong tendency to think that we could control water," said Joep Verhagen, Lead Expert on Water and Urban Resilience at the Global Center on Adaptation in the Netherlands. "Controlling nature gets harder and harder with climate change. So from controlling water, we moved towards living with water, accepting that we cannot always control nature." While the Netherlands' infrastructure remains among the best in the world, the rapid pace of climate change means parts of the system need updating, said Harold van Waveren, water-safety adviser at Rijkswaterstaat, the national water-management agency. "Because if you replace some infrastructure, the idea is that it will work for another 50 or 100 years," he said. "We feel so safe because it is going well. It has been going well, until now," Van Waveren added.
Holding back the sea
The Delta Works combines more than 20,000 kilometres of dykes and storm-surge barriers with thousands of pumping stations. "That is our main foundation," Van Waveren said, ensuring "this country exists". The pumps vary in size, with the largest currently pumping around 250 cubic metres per second. Yet pumping capacity may need to increase dramatically. "One of the options could be to construct pumping stations with capacities of 2,000, 3,000 or even 5,000 cubic metres per second by the end of this century in order to remain safe." Some Delta Works structures, such as fixed dams, block the sea. Others, particularly movable storm-surge barriers, remain open under normal conditions to allow shipping and natural ecosystems to function, but can close during extreme storms. Opened in 1986 and stretching 9 kilometres (5.6 miles), the Oosterscheldekering, the world's largest storm-surge barrier complex, has 62 movable gates that remain open under normal conditions to allow tidal flows and ecological processes to continue naturally. They close only during exceptionally high water levels. Since it was built, the barrier has closed roughly 30 times - about once per year on average - but under extreme climate scenarios it could close as many as 20 times annually, placing increased mechanical stress on the gates, according to a report by the Royal Netherlands Meteorological Institute (KNMI).
Another major water-defence structure, the Maeslant Barrier, was built to protect Rotterdam and more than one million people from flooding. The automated storm-surge barrier has two movable arms, each 210 metres wide, 22 metres high and 15 metres deep, which can sink to the bottom of the waterway within approximately two hours. It was designed to close roughly once every decade. In 2023, high water levels caused by Storm Pia triggered an automatic closure. Authorities warn that if sea levels continue to rise significantly, access to one of Europe's largest ports may eventually need to be permanently restricted. "Maybe for our safety in the longer term, we will have to close it. It is not an issue now," Verdaas said, "but with two metres of sea-level rise, it could become one by the end of the century."
Global sea levels are projected to rise by around 0.3 metres to just over 1 metre by 2100, depending on future greenhouse gas emissions, according to the Intergovernmental Panel on Climate Change (IPCC). While higher-end scenarios remain uncertain, sea-level rise approaching 2 metres by 2100 cannot be ruled out.
Located in the northwest of the Netherlands, the Afsluitdijk - a 32-kilometre dam - separates the freshwater IJsselmeer from the Wadden Sea. It supplies water for agriculture and drinking water whilst protecting large parts of the country from flooding. Rising sea levels and changing climate conditions are increasing pressure on the system, prompting upgrades such as new sluices and expanded pumping capacity.
Managing water on all fronts
The Delta Programme undergoes a major review every six years, with the latest assessment due in September. Ensuring sufficient funding remains a key priority. Currently, the Netherlands invests around 1% of its gross domestic product in water defence, but "we need to double our investment", Verdaas said. In 2026, the Delta Fund will allocate €1.9 billion. The total programme cost is projected at €38 billion between 2015 and 2050.
"We are also experimenting," Verdaas added. Several projects now use natural tides and sediment to strengthen the coastline by allowing sand, mud and silt to settle in targeted areas. "So it is not a contradiction between nature-based and technical solutions. Rather, technical innovation should work together with natural systems. That is the way forward." But threats are not limited to the sea. Rivers flowing through the country also present challenges, particularly as melting glaciers and heavier rainfall increase water levels. The Netherlands' Room for the River programme allows floodplains to temporarily store excess water during periods of high river discharge. "The floodplains are normally grassland where cows graze. During high water, these areas flood, cows are evacuated, and when the water recedes there is very limited damage," Verhagen explained. Paradoxically, some regions are also facing drought, prompting initiatives to store water for agriculture and drinking-water supplies. "Water is the language of climate change, so most of the impacts we experience come through changes in the water cycle. That means either too much water, too little water, or water that is not clean enough."
Working with nature
Dutch cities are also innovating to strengthen urban water resilience. Rotterdam, in addition to more than 1,000 pumping stations, features green roofs that store water and cool buildings, as well as public spaces such as Water Square that double as water storage during heavy rainfall. "It is a place around two metres below street level. When the weather is dry, people play sports, attend performances and gather there. But during heavy rainfall, it fills with water." Other countries have also adopted this idea.
Rotterdam is also experimenting with floating infrastructure, including offices, farms and homes that are resilient to rising sea levels. "You need to make resilience measures multifunctional," Verhagen said. The Global Center on Adaptation in Rotterdam is housed in the world's largest floating office, a 3,500-square-metre timber structure that is carbon-neutral and cooled using harbour water. "Our language is full of expressions such as 'we conquered the water' and 'we conquered the elements'. Now we have to cooperate with them in this new chapter. That is quite a shift," Verdaas said.
