It was a Yankee by the name of Mary Mapes Dodge who wrote ‘Hans Brinker, or The Silver Skates: A Story of Life in Holland’. The book was published in New York in 1865. It is about poor, 15-year-old Hans and his sister, Gretel. Gretel wins the Silver Skates, the prize for winning an ice skating race. After that, everything turns out for the best, and the Brinkers are one big happy family. The book also contains the story of the Hero of Haarlem. It is the world-famous story of a boy who sticks his fingers in a leaking dyke and prevents a disaster. But, did he really? Is building dykes in the long run the best strategy to cope with sea level rise, or should we rethink this policy?

The Hero of Haarlem was a boy of 8 years old, who delivered a cake to an old, blind man one day. Our future hero was such a sweet little guy. But the boy had forgotten all about time. When in the evening he rushed home, the following happened:

“Just as he was bracing himself for a run, he was startled by the sound of trickling water. Whence did it come? He looked up and saw a small hole in the dyke through which a tiny stream was flowing. Any child in Holland will shudder at the thought of a leak in the dyke! The boy understood the danger at a glance. That little hole, if the water were allowed to trickle through, would soon be a large one, and a terrible inundation would be the result.

Quick as a flash, he saw his duty. Throwing away his flowers, the boy clambered up the heights until he reached the hole. His chubby little finger was thrust in, almost before he knew it. The flowing was stopped! Ah! he thought, with a chuckle of boyish delight, the angry waters must stay back now! Haarlem shall not be drowned while I am here!”

It was at daybreak, after a very chilly autumn night, when he was finally discovered by a clergyman. Of course, this symbolized the aid of God. Still, the kid had his finger in the dyke solidly. This is how the dutiful boy saved the town of Haarlem and how he became a hero.

Haralem – The name of the town of Haarlem appears for the first time between 918-948 as the settlement Haralem located in West Frisia. Today, Haarlem is located in the province of Noord Holland. The etymology of the name is a combination of the word haar/harula meaning ‘sand ridge’ and ‘little sand ridge’, respectively, and of heem meaning ‘homestead’. So, ‘homestead on a little sand ridge’ (Van Berkel & Samplonius 2018).

With the foundation of New Amsterdam by the Dutch in the New Netherland colony, which later became New York City, the neighbourhood Harlem received its name. Read our blog post History is written by the victors – a story of the credits to learn more about New Amsterdam, the New Netherland colony, and what part Frisians played in creating all this.

Of course, the whole story of the Hero of Haarlem is fictional. Often, Hans or Hansje Brinker and the Hero of Haarlem are mixed up by the public and others, while they are two different characters in the book of Mapes Dodge (Jensen 2021).

Hero Arie Evegroen

There is, however, a hero in the Netherlands who did prevent a dyke, also called a levee, from being breached. His name is Arie Evegroen (1905-1988). He did not stick one of his fingers into the dyke. No, it was something much bigger! It was during the Watersnoodramp ('North Sea flood') of 1953. That infamous night, Saturday, 31st of January, dykes broke in the province of Zeeland, and 2,551 lives were taken. Nearly the same happened in the province of Zuid-Holland if it was not for Arie.

Saturday evening. The storm had breached the dyke named Groenendijk near the village of Nieuwerkerk aan de IJssel. Water was pouring in already. A few fingers would not do the trick this time. Arie and other men were sitting in the local bar, relaxed, nipping a jenever when the mayor walked in. He said he needed a ship to be used as a plug in the hole of the dyke. The mayor persuaded Arie to take his 18-meter-long grain barge Twee Gebroeders ('two brethren') and navigate this ship into the breach of the dyke. Arie succeeded. Quick as a flash, his ship was nicely parked in the hole of the dyke. With it, he prevented most of the province of Zuid Holland, including the cities of Rotterdam, Leiden, and The Hague, from being flooded that tragic night as well. An area of 3 million people was spared. Arie Evegroen is known as the Redder van Zuid-Holland ('saviour of Zuid Holland'). And great parking skills on top of it!

Building dykes: an arms race

Hans Brinker and the Hero of Haarlem is the type of story confirming the almost supra-natural belief that by keeping building stronger, fatter, and higher dykes, the dangerous sea can be warded off forever. That we can control nature. Sayings like: wer nicht will deichen, der muss weichen, in the German language, or wie niet wil dijken, moet wijken, in the Dutch language, are chauvinistic regional classics, and mean 'who does not want to dyke, has to give way'. Or, similarly, as they say in the Low Saxon language in the province of Groningen: Gain diek. Gain laand. Gain leev'n, which translates to 'no dyke, no land, no life'. But the enormous bulwarks that have been built along the southern North Sea coast, from the west in the region of Flanders in Belgium, all the way to the southwestern tip of the region of Jutland in Denmark, are the people’s enemy in the long run.

Dykes have a long history. On the tidal marshlands, dykes have been built from the beginning of the first millennium. These were so-called summer dykes: low dykes at the silted-up salt marshes. To protect the marshlands from the salty sea during summer, all under normal weather circumstances, this way making the marshes more suitable as arable land and for livestock for most of the season. Summer dykes did not protect the tidal marshlands from the standard storm floods of autumn and winter; for that, they were purposefully too low. Flooding fertilizes the land.

From around the eleventh century onward, higher dykes were being built. This concurred with large-scale, commercial peat excavation along the southern North Sea coast. Go to our blog post The United Frisian Emirates and Black Peat. How Holland became Dutch to read about the history of this brown gold. Here, behind and underneath the salt marshes, existed huge peat areas. Besides contributing to global warming already in the High Middle Ages by unlocking vast amounts of carbon, commercial peat cutting also resulted in massive loss of land during great floods. All along what happens to be the route of the Frisia Coast Trail. Sometimes even complete islands and towns disappeared into the waves in a single night; check our blog post How a town drowned overnight. The case of Rungholt. To halt this massive land-eating process, summer dykes were replaced by the bulwarks of today. At present (2025), in the Netherlands these snake-like monsters rise a staggering 12 meters above Ordnance Datum (abbr. MoD), and still rising. A true boa constrictor. In Germany, the sea dykes are in general several meters lower.

If the reader thinks that the Low Countries are the avant-gardists of dyke-building, sorry to say, they were not. Heavy dyke building started already with the Sea Bank built at the end of the ninth century, sealing off the salt marsh area of Fenland in eastern England.

Constructing high dykes was not something unique to the sea coast, either. For many centuries, this arms race also took place in the central river lands along the lower reaches of the mighty rivers Rhine and Meuse. Here, every community and village had to build its own dykes. If yours were higher and stronger than those of your neighbour, your neighbour would be at a disadvantage. Not you (Rooijendijk 2009). The much-celebrated Dutch tolerance explained in a nutshell. But this aside.

They were the people of the town of Sliedrecht, a small town at the River Beneden-Merwede, a branch of the Lower River Rhine, who became the ultimate river-dyke constructors in world history. For this Darwinian achievement, their descendants have been awarded world’s leading dredging companies, which made them filthy rich, too. Among others, their skills turned out to be indispensable when constructing the 30-kilometer-long Afsluitdijk ('enclosure dam') almost a century ago. But these dredging companies are reshaping the coastline of the United Arab Emirates as well, to give just one example. Deus mare, Sliedrechti litora fecit (God created the sea, the people of Sliedrecht the coast').

But the dyke-constructing race came with a price. Sealing off land from the influence of the sea means, first of all, that the land behind it no longer silts up. It even dries out and shrinks. Indeed, it turns into the contrary land as described in the book of Mapes Dodge about Hans Brinker and the Hero of Haarlem. Just as well, we can name it bathtub country without a drain. Furthermore, before dykes existed, the waterwolf could flow out over a vast area of tidal marshlands during storm floods. People lived on earthworks called terpen, i.e., artificial settlement mounds, that were on average not much higher than 4 MoD. Higher was simply not necessary. The sea just flowed out during storms over the huge salt-marsh area without, in general, causing too much damage because of this enormous storage capacity.

The highest terp of all is the one of the hamlet of Hogebeintum in the province of Friesland in the Netherlands, namely almost 9 MoD. Why the people of Hogebeintum built such a high terp in the Middle Ages, when a height of 4 meters was already sufficient, we do not know. Was it perhaps to show off? Look us having a big terp! Did they have too much spare time to kill? Anyway, want to learn more about terps from the west of the region of Flanders in Belgium to the south-western tip of Denmark, read our blog post Between Leffinge and Misthusum – Understanding the Basics of Terps.

Low summer dykes surrounding the terp on the tidal marshlands functioned also as small barriers to quiet down the waves during storms. After the heavy dykes had been built, the North Sea was – and is – being pushed up with onshore winds, resulting in a sea level rise during storm floods that is on average 1.5 meters higher than before the creation of high dykes. Therefore, the safety situations became much more dangerous if these dykes do not hold. Maybe this is the reason why from around the eleventh century onward, when big dyke building had begun, the number of deaths along the southern North Sea coast shows a sharp increase. Read our blog post Half a million deaths. A forgotten North Sea disaster… Thinking they were safer behind the wall, but in reality not.

Terps, a current solution – The need of giving more space to the river had been recognized in the central river lands of the Netherlands the last decennia. Here the big rivers can flow out during high water levels now. In the Overdiepse Polder in the province of Noord Brabant, even eight new terps have been erected as part of these new Delta Works. If you want to know how to erect a terp, find here the first and only DIY manual - Making a Terp in only 12 Steps.

Sea is such a diva

Now earth is confronted with rapidly rising sea levels because of global warming. Although archaeology and geography have largely abandoned the theory of sea transgression causing deterioration of the coastal zone of the southern North Sea, including periods of depopulation (Van Steensel & Chamuleau 2021), there is reason for concern. Within Europe, the area of the Frisia Coast Trail has been identified as the most vulnerable area to be affected by global warming. Can habitation along seashores continue in the long run? Should the dykes be reinforced and made even higher, broader, stronger, and fatter?

More and more people, even scientists, plead to stop, or at least to nuance this arms race. Leaving behind the ancient reflex wer nicht will deichen, der muss weichen. Their plea is to restore as much as possible the dynamics of the sea. Give the sea, just as has been done with rivers before, more space again. This way, land can silt up again, and the risks of dykes leaking and breaking will be less. No more Heroes of Haarlem or Arie Evegroens needed. Besides that, it will contribute to a spectacularly more diverse natural landscape.

Not controlling the sea, but managing it. Make a compromise. Work with the waterwolf, not fight it. So, when the sea level rises, the land will rise with it. It has been done already during the many centuries before high dykes existed. Why not do it again?

The inhabitants of the village of Holwerd in the northeast of the province of Friesland in the Netherlands even have quite advanced plans and the financial means for opening the dyke and giving way to the sea again.

This new strategy reminds us of a quote from the former Iraqi Minister of Information:

Mohammed Saïd al-Sahaf (2003)

Anyway, cutting the dyke in two creates inland tidal marshlands and a rich nature area. The project is named Holwerd aan Zee (‘Holwerd by the Sea’). Hopefully, the project will overcome the hesitation of the provincial government and the resistance of the LTO (Dutch agricultural organization) lobby, and, of course and foremost, by Rijkswaterstaat Noord-Nederland, the executive authority of the Ministry of Infrastructure. Do check the Holwerd aan Zee plans out.

Nearby, at the village of Blije, another grassroots (of course, Puccinellia grass) initiative exists. Here, the local community is building a new terp on the other side of the dyke at the salt marshes. This art project is called Terp van de toekomst (‘terp of the future’).

Giving access to the sea, the Wadden Sea specifically, is also being experimented with near the village of Bierum in the east of the province of Groningen. Here, openings have been made with tubes, creating a permeable dyke. The idea is to let the land 'grow' again (Schuttenhelm 2023).

Similar developments have taken place at National Park ‘t Zwin in the northwest of the region of Flanders, which is also the starting point of the Frisia Coast Trail. In 2019, the Internationale Dijk ('international dyke') was cleared to make way for the sea. Another example is the sluices of the massive Haringvliet storm-surge barrier in the Netherlands that are being left slightly open since recently to give salt water and migrating fish continuous access. A less strict separation of salt and sweet, which should stimulate biodiversity. And then there are the plans being implemented as we speak, with the Afsluitdijk ('enclosure dam') of which the River Fish Migration will be part. Again, to restore a more dynamic relation between salt and sweet water, between sea and land. Although, the 30-kilometer-long dam is also reinforced and heightened, too. Yes, still fattening the boa constrictor.

Lastly, universities like the one of Wageningen in the Netherlands, are experimenting with salty agriculture. To be prepared for the future, and because the process of (re)salinization is already taking place in coastal zones. The University of Wageningen also identified adaptation pathways for the Frisian coast how to cope in the long run with rise of the sea level, including some of the antique solutions of former Frisia.

Albeit it is all very small scale so far, these initiatives might be the first signs of a new way of thinking. The idea that total control and a totally engineerable world is not the sole solution, not even fully possible in the long run. The world and nature are just too complex. Do not put all your eggs in one basket is the advice.

Focusing on the sea and its coastline, the consequences are that people should learn to accept the sea and its salt again. With a rising sea level, there is a greater need for additional sea water storage during higher floods. This can be combined with the need to halt the land behind the dykes from shrinking and, where possible, let it silt up again. This will be more reliable in terms of safety. Above that, it will greatly enrich nature. As the Frisians in the region of Nordfriesland in Germany say today when their Hallig-islands (see further below) are being flooded: "After each storm the island has grown."

But people have to adapt and must learn to be more symbiotic and less parasitic in their behaviour. Perhaps an additional side effect can be achieved, too. When enlarging the surface of wetlands along the coasts worldwide, more carbon will be captured and locked again, since wetlands specifically are very effective in doing so. Helping to damp global warming in the meantime as well. There are many initiatives around the world to conserve and foster wetlands, including the Convention on Wetlands.

For those readers who think it is not possible anymore to live without high dykes, know that just south of the Danish border at the Wadden Sea coast of Germany people still do dwell in the full dynamics of the sea. To this day, they are regularly surrounded by water during high floods: Landunter, as they call it. Indeed, we talk about the Nordfriesen ('North-Frisians') and their islands and Halligen in the region of Nordfriesland. Currently, their terps are being raised, albeit not their summer dykes. These Frisians still try to let silt up the their islands with the rising sea levels, as has been done for more than 2,5 thousand years.

With all this in mind, we can take an example from the grassroots along the southern North Sea coast. Where communities slowly turn to the sea again and want to embrace it. Almost literally visualized with the huge sculpture of artist Jan Ketelaar on top of the bulwark-dyke at the village of Holwerd: a naked woman and man with their arms spread open, with their feet firm in the clay of the dyke, waiting for the flood to come (see featured image of this blog post).

Let’s understand from now on that the Hero of Haarlem is, in fact, a Dragon in Disguise. Let’s take those fingers out of dykes. Let’s make the wetlands of the southern North Sea coast, of former Frisia, flourish again! Or, inspired by the words of a certain former American President:

Note 1 – We work on a back-up plan as well, namely that the sea level rise will be mitigated by exporting the additional water to desert areas on the planet. Salty wetlands in Chad, Egypt and Algeria.

Note 2 - Mary Elizabeth Mapes Dodge (1831-1905) was born in New York City. She had a rough time when her husband left her behind with her two young children, and was found dead soon after. Although from a well-off family, Mary started to work as publisher and became a writer. Inspired by John Lothrop Motley's 'Rise of the Dutch Republic' and 'History of the United Netherlands', she wrote 'Hans Brinker, or the Silver Skates. It was published in 1865, and immediately was a bestseller.

Note 3 – A few years after this blog post, the plans of Holwerd aan Zee have been abandoned in June 2024. The provincial government of Friesland and Wetterskip Fryslân (‘water authority Friesland’) were not prepared to take the ownership and responsibility for the management of open-dyke construction. Bit silly conclusion after a decade of working on it together, and missing a unique opportunity make a coalition between a local community and stimulating biodiversity. Let’s hope wisdom comes with the years.

Note 4 – Featured image 'waiting for high tide' by Ketelaar (sculpture), by Venema (image).

Further reading

Berkel, van G. & Samplonius, K., Nederlandse plaatsnamen verklaard. Reeks Nederlandse plaatsnamen deel 12 (2018)

Jensen, L., Hoe de strijd tegen het water de Nederlandse identiteit vormde (2021)

Klerk, de A., Vlaardingen in de wording van het graafschap Holland 800-1250 (2018)

Knottnerus, O.S., Sea level rise as a threat to cultural heritage (2003)

Liefde voor Holland, Verhaal Hans Brinker berust op waarheid (2016)

Middendorp, H., Zuid-Holland ontsnapte ternauwernood aan Watersnood in 1953 (2018)

Nieuwhof, A., Bakker, M., Knol, E., Langen, de G.J., Nicolay, J.A.W., Postma, D., Scheper, M., Varwijk, T.W., Vos, P.C., Adapting to the sea: Human habitation in the coastal area of the northern Netherlands before medieval dike building (2019)

Oosthuizen, S., The Anglo-Saxon Fenland (2017)

Rooijendijk, C., Waterwolven. Een geschiedenis van stormvloeden, dijkenbouwers en droogmakers (2009)

Ruyter, de P., Vloeiend landschap. Over de toekomst van het Friese landschap (2016)

Schroor, M., Strategies for future flood protection in the Wadden coastal area: Exploring adaptation measures with cultural-historical elements in Fryslân (2019)

Schuttenhelm, R., Dijk met gaten moet Groningen mee laten groeien met de zeespiegelstijging (2023)

Steensel, van A. & Chamuleau, B., Water, land en dijken. Het ontstaan van middeleeuws Noord-Beveland (2021)

Teetied & Rosinenbrot (podcast), Die Weihnachtsflut 1717 – wer schützt heute die Deiche? (2021)

Vogelbescherming Nederland, Project Holwerd aan Zee stopt (2024)