Destination: Flevoland and Delta Works

Chantelle Bryant
Destination: History
15 min readFeb 12, 2023
Image drawn by author

With almost half of the Netherlands sitting below sea level you’d think they’d have a lot more flooding than they currently do.

The Dutch are amazingly good at controlling water and creating liveable, viable land out of the sea.

Reclaiming land from the sea

It’s true almost half of the Netherlands sits below sea level. But that wasn’t always the case. A lot of the land that’s now inhabited with buildings and roads and people, used to be under water. So short of an earthquake, how did the Dutch manage this? It’s actually quite ingenious.

The North Sea has always been a friend and a foe for the Dutch. Terrific sailors, the Dutch’s trading empire at one point knew no bounds, but when the North Sea decides it wants to see what’s happening inland, things don’t exactly stay calm. So through an amazing network of dykes, windmills and waterworks, the Dutch were able to control the tides of the North Sea and take back a significant amount of land for their own use while they were at it.

They’re masterful control over water makes it no surprise that in 2013, the Delta works, the series of dams that hold the water back, were voted the most prestigious hydraulic engineering project in the world. And you could also argue that the Netherlands work with only the brightest engineers to keep people safe from the ravages of severe and destructive flooding.

Not only were the Dutch able to take back land from the sea for living, they are amazingly good at giving the perfect amount of the right kind of water to the land for agriculture. The dams that they have built throughout the centuries have allowed them to manipulate not only the flow of water, but also to control the amount of fresh water and the direction of polluted water. So the Dutch have pretty amazing water quality.

And this expert management of water has been beneficial in creating new nature reserves and greenery areas like parks. Sounds like a brilliant place to be.

So this area of land that used to be water is called Flevoland, it’s a province pretty much in the middle of the country, and is the result of massive earthworks by the people of the Netherlands. There’s even a saying that the world was created by god, but Holland was created by the Dutch, and as we’re about to see that’s pretty much exactly what happened.

So basically the Dutch drained lakes and even part of the North Sea to create what is now Flevoland, which as it turns out is the largest artificial island in the world. Surely that’s something to be proud of, if you’ve got some Dutch heritage in you.

Flevoland itself, is made up of three polders that were reclaimed from the seabed of the former Zuiderzee, or Southern Sea. The water that surrounds Flevoland is now a Lake, Lake Ijssel.

Building something like this from scratch is no easy feat, and some excellent engineering went into making it happen.

Flevoland was drained in the previous century entirely by the ingenuity of man.

They used everything at their disposal, mainly a lot of dykes to drain the water and gain access to the sea bed.

What’s pretty fascinating is before they drained the Zuiderzee, there were already islands there, smaller ones, but islands none the less. Schokland and Urk, which we’ll get into more detail a bit later on, were forced to become part of a larger block of land.

But why would the Dutch need to have such strong command of water and using it to their advantage? Well the Dutch weren’t always so in control. They’re had to learn the hard way that water on land can be devastating.

Back in the 17th century, the water works engineers were wondering what they could do with the Zuiderzee, a perfect patch of water that could be doing a whole lot more for their country then just sitting there and looking pretty. And it was Hendric Stevin who came up with the idea of creating a massive dyke that stretched across the top of Northern Holland effectively turning the Zuiderzee into a lake.

But things kind of stagnated for a little bit, and it wasn’t until much later, in the 19thcentury, that plans were finally drawn up and the technology and economics were on their side. And it was around this time that the Zuiderzee Association was created in order to revise the plans and make sure everything was up to scratch.

With the public initially quite lukewarm about the idea of a massive dyke they quickly changed their minds in the aftermath of the 1916 flood. And the Zuiderzee Association moved quickly to solidify support for their plans. It wasn’t two years later, in 1918, that the Zuiderzee Act was passed in Parliament, which allowed for the enclosure and drainage of the Zuiderzee allowing reclamation of the land once held captive by the sea.

A year later the Zuiderzee Project Department was created to get started on building the dyke in 1920. But as we know, big projects can struggle when their true cost starts to become apparent, and even though the dykes were built, the project started to stall. But the government took a good long hard look at the Zuiderzee Project and decided that despite their economic problems they were going to push ahead.

The fact that they had the Zuiderzee enclosed was great, but it was only step one. They now had to break the Zuiderzee up into smaller lakes to begin draining the water bit by bit. And so multi-kilometre dykes were put in to create smaller lakes, effectively breaking up the Zuiderzee.

In 1930, the first of five polders, or tracts of land, were reclaimed from the sea. But things need to speed up a little bit. Each polder was going to be extremely useful especially in providing more living space with urbanisation creating a need for new land for not just residential structures, but also recreational areas.

During the Second World War, work on the project understandably slowed down, but the Dutch were determined to push on and the more workers they had working on the Zuiderzee Project the less there were for those damn Nazis.

After the war, things started to ramp up a little, and with land having been created and cultivated during the war, the Ijsselmeer Polders Department was able to begin distributing the land and the first residential areas started to be built. What’s pretty fascinating is that with every polder that was built, the workers learnt what worked and what didn’t, so each polder is quite different from last. And each polder grew and changed depending on the conditions, a great example is in Zuidelijk Flevoland, initially this polder was meant to be largely industrial, but because a wetland naturally developed it was cultivated and is now an attraction.

So with new agricultural spaces, living spaces, industrial spaces and natural spaces being built, the polders came at just the right time to ease densities in overflowing cities.

Then in 1986, Flevoland was officially made the youngest and 12th province of the Netherlands and is home to about 400 000 residents.

It may seem crazy enough, but Flevoland actually sits on the sea bed a good six metres below sea level. Through the help of those dykes set up all those years before and crafty pumping stations, the area is kept nice and dry. But the Dutch aren’t stupid they didn’t just stuff it full of people, a good portion of Flevoland is open countryside, even a couple of woods have been thrown in, and I’m told it’s a pretty sought after area of the Netherlands to live.

History and use of polders

So we know that the massive flood in 1916 was the catalyst for the massive dyke that would help with creating Flevoland, but it hasn’t been the Netherlands only run in with the wild moods of the sea.

Being one of the lowest-lying countries in the world, the Netherlands, by necessity, had to come up with ingenious ways of controlling the world around them. And with at least a quarter of their land already sitting below sea level, big storms have always been quite the worry.

But from what we can gather, right from the beginning people living in the area have been making it work.

There’s evidence that in the first century the Frisians, the first settlers in the Netherlands, were building their villages and towns on top of artificial hills, known as terps, to keep them above the flood level. And then they figured out if they connected the terps with walls, effectively creating a dyke, they could keep their farmlands dry as well. And things really took off from there.

Soon the Dutch started looking at these flood plans and marshes and lakes and started wondering what a dyke could do in there. And so sure enough dykes were built around these bits of land creating some early polders. But we still have the issue of soggy land, that isn’t all that useful for building on or growing on. So of course the ingenious Dutch came up with an early version of pumps driven by a windmill and now you’ve got water being drained out of soggy land.

For more than 2000 years, the Dutch lived their lives holding back the water and reclaiming the land around them. But we know they were not immune to the ravages of an angry sea and every now and then got quite devastating floods, such as the one back in 1916.

As it turns out Flevoland has had quite the history even before it was reclaimed. Many archaeological finds have been revealed, mainly during the draining, like shipwrecks and former islands.

Now Flevoland as a modern province has been quite the producer. Being quite flat, it’s well suited for a selection of apples, flowers, cereals and even dairy cattle.

Delta Works

Because of the perpetual risk of flooding, the Dutch came up with a new construction project in the 1950s, the Delta Works.

Consisting of 13 sections the Delta works form the largest flood protection system in the world. 4 barriers and 9 secondary dams do the job of closing off the mouths of the inlets, protecting them from the destructive power of the North Sea. These dams effectively shortened the coastline exposed to the North Sea by about 700km, dramatically reducing the risk of flooding to low-lying and sometimes under-lying tracts of land. What’s really crazy about the Delta Works is that the salt water that was now trapped was gradually replaced with freshwater from inland rivers, creating a reliable way to water agricultural areas.

But just hold on a second, we’re getting a little ahead of ourselves, let’s head back a little further and find out how they even came up with the idea for Delta Works.

Delta Works came about after a study in 1937 conducted by Rijkswaterstaat, or the Department of Public works, found that safety for a lot of the Netherlands couldn’t be guaranteed during storms or higher than normal sea levels. So the initial solution they came up with meant closing all the river mouths. Dubbed ‘Deltaplan’ this was sure to work, no water going in or out meant no flooding. It’s as easy as that.

So in 1950 work started on closing off the river mouths, and it seemed like was going great guns, not only was the area safe from floods, they were also now getting a supply of freshwater, because the saltwater flow had stopped.

And so with the work done so far looking pretty great, the plan going forward was to continue damning the rivers and live life safe from floods. Unfortunately the North Sea had other plans.

The flood of 1953 turned out to be the greatest natural disaster the Netherlands has experienced in the last century. A bad storm and spring tides teamed up to really do some damage. A tidal wave came through and broke the dykes in several places effectively making them useless and the water flooded the islands. With the dykes already compromised, they just couldn’t hold back the sheer amount of water and ended up failing in 150 places. The results were catastrophic. 2000 people lost their lives and more than 150 000 hectares of land was flooded.

But if the dykes were already in place, then how could this have happened in the first place? The answer to that question is in maintenance. The dykes hadn’t been maintained and were in such a poor condition they really stood no chance against the force of the swell. Probably thanks to the war, the water boards had invested too little and carried out the bare minimum in terms of maintenance on the dykes.

Thankfully, it seems after these bad floods the Dutch have a pattern of setting to work to prevent it from happening again, and so they did in 1953.

Not 20 days after the water had subsided, the Delta Project was launched by the Dutch government with the express purpose of protecting the people of the Netherlands from the North Sea. And in 1958, these purposes were laid down in Parliament as the Delta Act.

In order to protect the people, it was decided that dams would be needed at the river mouths, known as ‘compartment dams’ their use would be to divide large areas of water into smaller, easier to manage compartments. This work, that would go by the name of ‘Delta Works’, would be such an enormous project that many would refer to it as the Eighth Wonder of the World.

By 1958, we’ve got the first part of the Delta Works in place and operational. The storm barrier in the river Hollandse Ijssel was extremely important because it protected some pretty densely populated parts of the Netherlands. Three years later, in 1961, both the Veerse Gat and Zandkreek were closed as well. And thanks to those inland rivers both dams now hold fresh water.

But probably the most ingenious part of the whole thing, are the sluices. Built in the mouth of the Haringvliet and used to drain the excess water coming from the Rhine, the sluices are used to control the flow and keep the river in use year round. So during the extremely cold winters, when the water would normally freeze, the sluices can be opened allowing in sea water from the North Sea and preventing the river from freezing over.

By the time we get to 1971, the sluices which are 1760 metres wide are fully operational and working excellently. But when the project started looking at closing the mouth of the Eastern Schelde, they came up against some environmental issues. If they were to close off the Eastern Schelde, the water would become fresh like the other closed rivers, but the Eastern Schelde was home to a unique salt water environment and some were concerned about the loss of this environment if fresh sea water was cut off, namely those in the fishing industry.

So the Dutch government sat down and put their thinking caps on. And by 1976 had come up with what they thought was a pretty impressive alternative.

Instead of building a dam and closing the river off, they would build an open barrier, so more sluices, that could be closed when things got a bit hairy, like heavy storms and high water levels. And when things were calm, the sluices could be open allowing water to once again flow through. And that’s exactly what they did. So now you can see 62 openings, each opening measuring 40 metres wide that allow water to move through normally, but when they need to they can close the mouth off, effectively controlling the tidal movement. This, frankly, impressive endeavour became the Eastern Schelde storm surge barrier and is one of the largest structures of its kind in the world.

Not only have the Delta Works project saved lives, they have had so many other significant advantages as well. There’s the freshwater supply for agricultural land, thanks to the cut off rivers, allowing for better quality produce. There’s the ability to allow fresh, clean water in and push the polluted water out, just making the whole place a bit nicer in general. You’ve got the ease of transport along inland waterways, without changing water levels, allowing ships and boats to move along with more certainty. And while some natural environments were damaged because of the closure of the river mouths, new ones popped up.

And so, in 1997, 44 years after the massive flood disaster, the Delta Works was officially finished. With all the dams reducing the length of the coastline open to the North Sea, they’ve been able to protect countless people, homes, businesses and industries.

But thanks to climate change we’re seeing an increase in water levels the world over. And so while maintenance on the sluices and dams have continued, some dams have also had to be heightened to handle the extra height of the water. And thanks to the fact that not enough is being done to tackle climate change, the Delta Programme has been forced to actively monitor the situation and start to collaborate with others about possible solutions for the very near future. The Delta Programme believe that the current infrastructure will be able to protect against floods until at least 2050, after that they’re not sure what will happen, so they are now investing in knowledge building and new technologies that will allow them to adapt to whatever situation 2050 throws at us.

Places to go and see

Now if you ever find yourself in the Netherlands and decide to visit the polders of Flevoland and the Delta Works what is there to see except massive islands and peoples houses? Well you might just be surprised.

There are roads and bridges that connect the Delta Works and surrounding areas, so you can definitely have an explore of those. And there’s even an app, the Zeeland app that show all sorts of bicycle routes to explore the cool things about the Delta Works for yourself.

As for Flevoland, we already know that there are many beautiful green, natural spaces to wander around. As well as some pretty interesting art and architecture. As for top tourist spots, there aren’t that many, as the polder itself is probably the main attraction. But you can certainly see some of the awesome things they found when they drained the Zuiderzee, such as a replica of 17th century East India Company flagship the ‘Seven Provinces’, and other exciting archaeological finds.

Now Schokland and Urk are two islands we briefly touched on at the start, and you might be surprised to learn that you can still visit them today, although they’re no longer islands.

Schokland is actually a World Heritage Site, and is full of archaeological treasure. People have lived in Schokland for centuries, constantly battling against the water, so there’s plenty to explore. At some point, about 150 years ago, they did decide that they were just too exhausted against the continuous storms, and the island was actually evacuated, but of course as we know when the water was drained the Schokland became apart of the mainland, no longer a tiny island.

Now Urk is what you would call a traditional fishing village, and is so different to the rest of the very modern Flevoland, and it’s probably this that makes it a great place to visit. Like many fishing villages, Urk kind of built up naturally, with a warren of small streets, it’s in pretty stark contrast to the clean urban plan of Flevoland. Basically Urk is just one massive open-air museum, and even though, like Schokland, it is no longer an island in its own right, it has still retained it’s island charm.

Another place I think would be worth a visit is Batavialand. Found at the very heart of Flevoland, you will be transported back through 7000 years of Dutch history. It’s here that you’ll discover everything you could possibly need to know about the Netherlands, their people, and their perpetual struggle against the ever unruly water. You can even see how they would have built trading ships over 300 years ago. The ingenuity is astounding.

But I think the place that I would want to visit the most is the Waterloopbos. So how would you go about calculating the extremely complex forces of nature on major water management projects without the magical computer programs we have today? Well the answer to that is to create a scale model. Back in the analogue days, engineers would have to get a little bit creative on how to test their ideas without the help of technology and that’s where Waterloopbos comes in. Basically it’s a Hydraulic Laboratory, where hydraulic engineers would build scale models and conduct their testing from the 1950s all the way through to the 90s. Even Delta Works was tested here, along with dams and other water management systems for other parts of world like Rotterdam, Lagos, Bangkok and Istanbul.

What makes Waterloopbos such a great site for this testing is that it sits right on the edge of old land and new reclaimed land, meaning that it has natural rapids. With the water flowing from the higher old land to the lower new land, the engineers had a great opportunity to test their inventions using the natural forces that their projects would face in the normal sized world. No testing has been done in decades, mainly thanks to the technology revolution, so many of the models have been reclaimed by nature, and there’s plants and shrubs growing over ducts, weirs and sluices. But I’ve heard it’s a terrific place to wander around and marvel at the 35 remaining hydraulic projects. And the Dutch seem to think it’s a pretty awesome place as well, because in 2016 it was actually named a national monument.

So what are you waiting for? Head on over to the Netherlands and check out the ingenuity of their engineering marvels.

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Originally published at https://destinationhistorypod.com on February 12, 2023.

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Chantelle Bryant
Destination: History

On an eternal journey of learning, forever finding new things that tickle my fancy, striving for polymath status.