When the Afsluitdijk was completed in 1932, it was a feat of Dutch engineering. The enormous dike extends straight into the water, cutting off the North Sea. What was once a bay became the freshwater lake Ijsselmeer.
In the middle of the dam runs the A7 motorway, which connects the provinces of North Holland and Friesland, and ships pass through the lock systems daily.
Higher and stronger
But 20th-century technology is not enough to deal with the climate of the future. When sea levels rise and storms get worse, the faithful servant is no longer up to the task.
The embankment needs to be higher and more resistant to waves. We have seen in recent decades that the waves are getting a little higher, that the sea level is rising, so we had to take action, says Peter Jansen at Rijkswaterstaat, which is responsible for protecting the Netherlands against the forces of water.
In addition, water pressure is also increasing from within – a branch of the Rhine River flows into the lake. Regulation is normally done with weirs at low tide. But the lake needs to be controllable even when the sea level is high.
In 2019, the renovation of the Afsluitdijk began, at a cost of approximately one billion euros. Additional floodgates and six newly installed large pumps have just been built, with a combined capacity of 235 cubic meters of water per second.
If everyone is working at the same time, it is enough to reduce the water level in the lake by two centimeters per day. Last winter there was a flood, where the pumps could have been helpful, says Thessa Popma, who is the visitor coordinator for the project.
Not even until 2050
The seawall itself has been raised two meters and covered with 75,000 specially designed concrete blocks weighing several tons each. They are designed to withstand a superstorm where sea levels press on the wall, while high waves crash over it.
The Afsluitdijk is just one of many projects the Netherlands is implementing to address rising sea levels. Yet the massive renovation is short-term. From 2050 onwards, new measures will need to be taken.
"We made the plans based on climate projections from 2010. They have already changed. So now we think that what we are building now may not even be enough for 2050," says Peter Jansen.
Gustav Sjöholm/TT
Facts: Afsluitdijk
TT
The Afsluitdijk is a dam, or embankment, connecting the provinces of North Holland and Friesland. It was built as a flood protection and was completed in 1932.
The dike closes off a bay belonging to the Wadden Sea (part of the North Sea), so that the freshwater lake Ijsselmeer is formed on the inside.
On top of the Afsluitdijk runs the A7 motorway, where 20,000 vehicles pass daily, and there are locks for ships through the structure.
Extensive renovation work has been underway since 2019, which is now largely complete.
