Design for a multifunctional Afsluitdijk whose duties of defending the coast, discharging water, generating energy and carrying traffic are sustainably integrated whilst conserving its spatial qualities.

The Afsluitdijk causeway needs tackling effectively, if only because it no longer meets the requirements of the Flood Defence Act owing to the rising sea level. On March 14th, 2008, the national water authority (RWS) organized a symposium on the future of this barrier dam which called for combining an all-in response to the problems with exploitation of the potentials on site. This project steps off from the 2008 symposium. Several issues need resolving. First, there is the increased pressure on the Afsluitdijk from the North Sea due to the sea-level rise. Next, there should be a gradual increase in the discharge of rainwater via the Afsluitdijk into the Wadden Sea. Large quantities of freshwater unleashed on the saline and brackish Wadden Sea are killing fish and bringing disease. There are also problems with the causeway itself. Motorists crossing it only get a one-sided view of the IJsselmeer lagoon as the Wadden Sea is obscured behind the causeway. The Afsluitdijk holds few attractions for cyclists either at present. Ecologically, it forms a barrier between two systems, freshwater and brackish-saline, obstructing the natural water flow and preventing the migration of fish between their adult habitat and breeding grounds in the rivers to the North Sea and vice versa.
This project seeks to design an Afsluitdijk that is safe and retains its identity as an icon standing for the perpetual struggle against the water. The design conserves the Afsluitdijk's spatial qualities and exploits its potentials, retaining the causeway as a slender linear element. Newly created salt marshes and artificial reefs maintain a sense of unity and openness. The salt marshes are as much ecological as defensive and recreational in their functioning. The reefs not only give protection against the waves but enable fresh and salt water to mix, making the project of great value ecologically. Fish find the brackish water flow and can bypass the dam along a fishway. The properties of the Afsluitdijk and its surroundings are used to generate sustainable energy through osmosis and solar collectors. The dam's outline has been modified to a minimum to give the water a higher profile, whilst retaining its own identity. It has been made 2.35 metres taller and the cyclepath moved to the IJsselmeer side.
All in all, the Afsluitdijk in this design is multifunctional, with sustainable energy production and increased ecological value integrated into the principal duties of guaranteeing safety, discharging water and connecting Noord-Holland and Friesland. Its spatial qualities are used and strengthened where possible without compromising its identity and iconic status.

Place of education: Wageningen Universiteit | Specialization: landscape architecture | Tutor: Ingrid Duchhart