Afsluitdijk

Six mega pumps, part of the pumping station, are one of the few made-visible constructions on the dike. Together they can discharge 275,000 liters of water per second from the IJsselmeer to the sea, fast enough to fill an Olympic swimming pool in just nine seconds. Each pump is protected by a colossal glass dome: 9 meters in diameter, 4 meters high, and weighing 30 tons. In contrast to the complex technologies embedded in the pumping station, the domes are designed in an abstract and simple manner. The transparent domes protect the powerful motors from the elements, waves of the Waddensea and spectacularly showcase the water drainage functionality to passing traffic. Each dome is also designed to be lifted off as a whole, allowing to quickly replace a pump when necessary.

The primary function of the dike is to protect the land from the sea and to regulate water flow. The discharge complex at Den Oever has therefore been expanded with two new discharge sluices, set between the monumental Stevin Sluices. When the water level in the Wadden Sea is high, sluicing is not possible; for those conditions the pumping station with six pumps was built.

On the Wadden Sea side, the dike has been reinforced with seventy thousand Levvel-blocs of 6,500 kilos each, designed specifically for this project. The shape of the block breaks the waves, is more efficient to lay, contains 25% less concrete and emits 56% less CO₂ than its predecessor. The surface has been left rough so that vegetation can take hold; this is already happening. Its symmetry and regular placement produce a calm image in keeping with the taut, autonomous character of the dike.

To restore the migration route between the Wadden Sea and the IJsselmeer, a fish migration passage twenty meters wide was designed. For the first time in almost a century, some twelve fish species can expand their habitat. The passage was designed with attention to ecology, form and surroundings. The true scale of the fish migration river can be experienced first-hand; it is open to visitors.

The Afsluitdijk is first and foremost a water barrier, but the design also makes the work accessible. A new cycling and walking route crosses directly over the engineering works, where visitors stand on the moving parts themselves; the materials change there and viewing platforms widen into squares. At the Vlieter, halfway along the dike, Benthem Crouwel designed the service area and the footbridge. The solar park at Den Oever, laid out in a fan shape with space between the panels for ground vegetation, supplies power to the installations on the dike, including the pumps.