Katwijk coastal protection: Dike-in-Dune with a parking garage
The village of Katwijk on the coast of South Holland is home to a unique, multi-functional flood defence: a dike, covered in sand, with an underground parking garage.
Katwijk was one of the weak links in the Dutch coastal defence as the dike there had lost its function. It no longer ran along the coast, but instead cut through the middle of the village. Under certain conditions, a superstorm combined with extremely high water levels could flood the centre of Katwijk and even a large part of the Randstad urban conglomeration. The buildings along the dike made it impossible to reinforce the dike itself due to the lack of space, so the coast has been reinforced instead, protecting the village behind the dike once more.
The Rijnland Water Authority, the municipality and the residents chose a broad, low dike so that the Katwijkers’ beloved view of the sea could be preserved. The result was the construction of a wide row of dunes in front of the dike to break the action of the waves.
In order to create the extra space necessary for this, the beach was moved 100 metres towards the sea, resulting in the reclamation of new land from the sea. The dike was then covered in sand so that it would blend better into its surroundings.
This solution also created space for building an underground parking garage between the boulevard and the beach, which will reduce some of the parking congestion in the nearby residential areas. The parking garage was built against the dike and hidden under the new line of dunes. This specific combination of flood protection and parking is unique in the Netherlands.
In Katwijk, the Flood Protection Programme has constructed a Dike-in-Dune with an underground parking garage. This unique combination of functions helps to reduce parking congestion in residential areas, while preserving the Katwijkers’ beloved view of the sea.