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The Afsluitdijk is a dike of world renown. For 90 years it has protected our country from the force of water. This also means that the dike is already 90 years old. A time period in which much has changed, just look at the effects of climate change. In addition, the Afsluitdijk no longer complies with the current Water Act. High time for a large-scale renovation and reinforcement. It immediately provides opportunities for many innovative and sustainable initiatives.
"The assignment for renovation and reinforcement of the Afsluitdijk was twofold; ensure that the existing Afsluitdijk once again meets the standards for water safety and ensure that it has extra discharge capacity to keep the IJsselmeer level," explains Wop Schat, project manager at Rijkswaterstaat. "Looking at the first task, we are talking about the renovation of the sluice complexes, the construction of two new floodgates that will take on the function of high-water protection, and the dike itself, which we are making flood-resistant. That is, it will be able to withstand a superstorm that may occur once every 10,000 years. In addition, the water supply to the IJsselmeer will become more erratic in the future. So we have to be able to discharge more water in short periods, this was the second task. This is why we are building two additional sluices and two pumping stations in Den Oever. The energy used by the sluices and pumps will be sustainably generated with solar energy on and around the Afsluitdijk."
The renovation and reinforcement of the Afsluitdijk will make it a multi-dike, so to speak. Previously intended primarily to protect the hinterland from high water, today the dike is a water barrier, an important connection between Friesland and North Holland in the form of the A7, and a place where innovation takes place. Examples of innovation include the Vismigration River with its composite sluice gates, the Levvel blocks, the Quattroblocks and the sand conveyor across the A7 about which you will read more in the following articles. Schat: "The renovation of the A7 also definitely deserves attention. We made it safer. Big challenge here was that widening was not just possible, after all, you have water on both sides. That's why we narrowed the central reservation by installing an innovative guide rail, which made it possible to widen the emergency lanes. The road surface was also completely renewed. Low Energy Asphalt Concrete (LEAB) was used for this purpose. This type of asphalt is produced at a temperature as much as 30% lower than traditionally produced asphalt. This provides energy savings and CO2-reduction. The project an sich also provided an opportunity to challenge parties to look at sustainable energy," Schat explains. "As a result, thanks to the solar farm at Den Oever, the dike is an energy-neutral dike. To reduce energy consumption even further, the basic principle is: we drain when we can and pump only when we have to."
Although not originally part of the renovation, the Kite Monument is also being restored. Rijkswaterstaat is restoring this structure by Dudok to its original state and modernizing it at the same time. "We are expanding it with a larger catering facility with a view over the IJsselmeer and there will be a new footbridge. The statue of Lely will retain its prominent place and on the Wadden Sea side there will be a large viewing balcony. With all this, the Vlietermonument will become a place where everyone can experience the history of the Afsluitdijk."
The renewal of the dike is an extremely special and also complex project that is expected to take eight years in total. The start was in 2018 and the planned completion is in 2025. Besides being technically very complex, it is also logistically quite a task. "In retrospect, the Department of Public Works and Levvel underestimated that," Schat says. "It requires a lot of blood, sweat and tears. That makes us all the more proud that all the parties involved together have succeeded in making the Afsluitdijk future-proof. Together, we have been able to 'lift' the iconic structure that engineer Lely erected back then into the modern age with an eye for technology and spatial integration. The Afsluitdijk has only become more beautiful and an ultimate example of Dutch glory!"
