(Words appear in white letters on a blue screen. "De Afsluitdijk. The building blocks of an icon." Footage of De Afsluitdijk.) CALM INSTRUMENTAL MUSIC MAN: The Afsluitdijk is levelling up. This Dutch icon of hydraulic engineering... is getting a well-deserved upgrade, the first major one in 90 years. Time to take a look at what we're doing to make sure that The Dike that Closes Off... never shuts down. You're watching Waterworks... a series of educational videos about the Afsluitdijk... in which we take a closer look at this beloved dam. Despite the fact that the Dutch name refers to it as a dike... it is actually a dam, which closes off parts of the sea surrounding the Netherlands. In this video, we'll focus on the custom-made technical marvel... that will protect the Dutch landscape for the next 100 years... Levvel-blocs. We'll also talk about superstorms, titans, ballerinas... and the mother of all testing grounds: the Delta Flume. So let's go. In the Netherlands, we've always been at the forefront of hydraulic engineering. We plan for the worst, but hope for the best. And when 60% of your country is vulnerable to flooding... high standards and requirements for protective measures... are something you take very seriously. (Storm footage.) Superstorm seriously. We set our standards to withstand... a mix of circumstances that only occur once every 10,000 years. A superstorm that would sweep away... all the old basalt blocks that used... to cover the Afsluitdijk like pebbles. But don't worry. A storm of this magnitude has never happened. Yet. These standards, coupled with a slight decay... of the existing dam elements and the uncertainty... of climate change, were the reasons... why experts called for the first major upgrade since 1932. That's right. The Afsluitdijk has gone an entire lifetime... without heavy maintenance, even withstanding the 1953 flood disaster... an impressive feat. The new and improved Afsluitdijk... will protect against rising sea levels until at least 2050... which is based on current climate change estimates... of a sea level rise of 0.35 meters by that time. Some parts are even built to last 100 years... like the revetment. By implementing smart measures now... it will be possible to further reinforce... the dam in the future with relatively simple interventions. This is called Adaptive Delta Management. Like we said: Hope for the best, plan for the worst. (Traffic footage.) As you all know, a sound technical design... is the most important aspect. But we also want to protect the adjacent UNESCO nature reserves in the Waddenzee. This means expanding the circumference of the dam... as little as possible, while also minimizing the CO2... impact of production materials and transport. We have a saying in the Netherlands that literally... translates to: the eye also wants something. We honor that saying by preserving the classic Afsluitdijk look of spectacular simplicity... and thereby preserving a piece of Dutch history. (He looks serious.) Protection and preservation. These are two words that we returned to again and again. These requirements together resulted in this design. Now, we know engineers love getting technical. So let's dive in. (Footage of builders.) RHYTHMIC MUSIC We start our tour at the toe of the dam... which was built with rocks up to 2,000 kilograms. On the lower slope, we used something... called Levvel-blocs, which are huge plus-shaped blocks. And we'll talk more about those later. And finally, an asphalt berm on the storm water level... to reduce wave overtopping... which also serves as one of the most beautiful bicycle... paths in the Netherlands, with a spectacular view... of the Waddenzee. (Footage of the finished bicycle path.) The upper slope of the dam will be protected by different blocks... that are known as Quattroblocks... which consist of four distinct blocks that form a basalt-like texture... when connected together. As you know... rough surfaces break waves much better... thereby reducing wave overtopping. Basalt isn't a rough surface however... but there's nothing a little Dutch ingenuity can't fix. You see those ribs in the dam's surface? Those are high and low Quattroblocks mixed together. This way its looks resemble the classic Afsluitdijk... but it breaks waves like a modern powerhouse. (He smiles.) Now, let's talk about Levvel-blocs. We developed these blocks, especially for the Afsluitdijk. As you can see they roughly resemble a plus shape. Placed next to each other they create a surface that is rough and porous enough to dissipate wave action... while keeping the spectacular simplicity of the original Afsluitdijk look. The plus-shape offers great stability while using much less concrete than its... predecessors, the Xbloc and the Ybloc. Also it looks like a work of art when stacked together, and we stacked... a lot of them together. How many? 70,000 Levvel-blocs in total... each about a meter high and 6,500 kilograms in weight. That's 487 million kilograms in total. See this large hole? It serves two purposes. During construction a clamp inside the hole helps cranes to lift them up. This is a big help for a block that weighs as much as an elephant. Once in place, the hole also allows for efficient water drainage... thereby reducing the uplift pressure during an extreme wave attack. (Footage of white Levvel-blocks.) The Levvel-blocs were created especially for the Afsluitdijk... but will live on under a different name, the XblocPlus. We can already see an example of its protective qualities on Vistula Spit in Poland. On the inner slope and the crown... we flexed some centuries-old hydraulic muscles with a tough clay layer... topped with grass. Both are excellent water barriers. These layers form an effective water barrier to protect the inner slope from... erosive damage caused by overtopping waves. But a great design is worthless if it doesn't work. So we tested a lot. Someone who knows everything about testing is Bas Reedijk. Bas, how exactly do you test a dam? PEACEFUL MUSIC (Bas Reedijk, Senior Coastal Engineer.) We started with computer modelling, but when designing for a 45 hour superstorm... with significant wave heights of over four meter and water level of more than... five meters above mean sea level, then real life tests are essential. This is firstly done by physical model testing in small scale wave flumes at a... 1 to 30 scale and then again and again... testing it and perfecting it a little bit more every time. After that it was time for the mother of all wave flumes, a 300 meter long channel... five meters wide, nine and a half meter deep giant that's called The Delta Flume. It's the largest of its kind in the world and it's located on the grounds of... The National Hydraulic Laboratory in Delft. The Delta Flume holds 9 million liters of water and can create life-size waves. It's even capable of generating the superstorm waves we talked about at the... start of the video on the one to three scale. the Levvel-blocs passed with flying colours. Just to show off, we even tested the blocks at twice the power of superstorm waves. They didn't budge. When it was time to actually install them on the Afsluitdijk... the team used a huge crane called the Titan which was specifically designed for the job. Quite a contrast from the crane that placed the Quattroblocks, which is called the Ballerina. (The Ballerina installs blocks.) So safety? Check. Looks? Check. Nature? Ofcourse we didn't forget about nature. The shape of the... Levvel-bloc, for instance, is rugged, which creates holes and cavities when the blocks are placed... side by side in addition to the big hole in the center of the block. These cavities are great for... algae, plants and shellfish, among others. They essentially become an artificial reef... creating a surface for all kinds of creatures, plants and other underwater life forms. A large strip of... grass and flowers will also form a bee-highway adding to our collection of animal infrastructure... solutions like the Fish Migration River. Our emission reduction goals were met as well. The shape of the Levvel-bloc, the optimized production and transport process... helps to reduce CO2 emissions by 55% compared to conventional armour, production and transport methods. All these aspects together make up the literal and figurative building blocks of the Afsluitdijk. Want to know more? Watch our other videos. For now we'll see you next tide. (He smiles.) CALM INSTRUMENTAL MUSIC (The logo of De Afsluitdijk appears. Below, in front of the profile name "De Afsluitdijk", five logo's appear of Facebook, Instagram, Twitter, LinkedIn and YouTube. Commissioned by Rijkswaterstaat, Ministry of Infrastructure and Water Management. With the cooperation of: Levvel, Lely's Erfgoed Veiliggesteld and Vismigratierivier.nl.)
Second place 2025 Jan Agema Award for Afsluitdijk causeway reinforcement
The innovative reinforcement of the Afsluitdijk causeway was awarded second place in the 2025 Jan Agema Award for hydraulic engineering projects. This was announced during the Waterbouwdag (Day of Hydraulic Engineering) on Thursday, 9 October 2025. Second place for this prestigious award is a marvellous accolade for one of our unique projects.
Jan Agema Award
The Jan Agema Award is awarded once every five years to encourage innovation in hydraulic engineering. The prize goes to the best and most innovative hydraulic engineering project completed in recent years.
When awarding the prize, the expert jury took into account factors such as innovation, the positive impact of the project, and its implementation. Thirteen projects were submitted, of which three were nominated. The winner of the 2025 Agema Award was the Borssele Wind Energy project.
Nevertheless, reinforcement of the Afsluitdijk received praise from the expert jury: ‘The Afsluitdijk Causeway Reinforcement Project stands out for its innovative and meticulous approach to an iconic element of Dutch hydraulic engineering. The jury praises the innovative reinforcement with an eye for landscape, ecology, and the specially developed Levvel blocks, which are being emulated worldwide.’
Causeway reinforcement essential
The construction of the Afsluitdijk was completed in 1932. Due to climate change and stricter standards for dikes, the Afsluitdijk had to be renovated after almost 90 years. The Levvel construction consortium (BAM, Van Oord, Rebel, and Invesis) was commissioned by Rijkswaterstaat to begin reinforcing the causeway in 2019 and completed the work in 2023.
Innovative request for proposal
Emiel Boerma, Technical Manager at Rijkswaterstaat, explains: ‘As principal, we strongly encouraged innovation on the Afsluitdijk. But if you allow innovation, you get solutions that have never been proven or tested before. That is why we specified in the Request for Proposal that the design had to be extensively tested in the Delta Flume.’
‘Furthermore, there were strict requirements from the surrounding area, partly because the Afsluitdijk lies between 2 Natura 2000 areas. It was a major undertaking, with effective cooperation between principal and contractor being key. But looking back now: everything’s in there. We’ve not compromised on anything. The causeway looks great, is demonstrably super strong, and is full of innovative solutions.’
Innovation in design and implementation
From the tender phase onwards, Levvel worked on pushing the boundaries in hydraulic engineering. The scale and uniformity of the Afsluitdijk offered opportunities for innovation, but also required extreme care.
‘After all, any unforeseen problems could be repeated along the full 32 km’, says Sjoerd van den Steen, Design Manager at Levvel. The most striking innovations are the new cladding elements: the Levvel block on the lower slope and the ribbed pattern of the ‘Basalton-Quattroblock’ facing stones on the upper slope. Both have been extensively tested with scale models in wave flumes. Not only for stability, but also to determine tolerances during construction and maintenance.
Van den Steen: ‘Thanks to this approach, we were able to save approximately 60% concrete compared to a traditional design.’ Levvel also opted for smart solutions in the implementation. Two unique placement machines (Ballerina and Titan) were developed, a temporary channel was dredged along the dike, and a semi-automatic factory was built to produce 70,000 Levvel blocks.
Recognition
‘It was an extremely challenging task with a tight schedule and high quality requirements in all project phases. The second prize is recognition that this is truly an engineering feat and a reward for the many colleagues who worked on it’, says Van den Steen, looking back.
Rolf Bruins, Hydraulic Engineer at Rijkswaterstaat, adds: ‘The project in a nutshell: technically advanced, great collaboration, and innovative. The Afsluitdijk was already an icon and remains a gem of a causeway, combining technology, aesthetics, ecology, and innovation. I think it’s really cool that we have successfully reinforced one of the most important causeways in the Netherlands with new innovative elements.’