Posted on 1 May 2018
The 32 km long Dutch closure dam Afsluitdijk will be enforced with 75,000 specially designed armour units that will be equipped with sensors to monitor their individual status. This has been announced by the Levvel-consortium and the Dutch national authority of public works Rijkswaterstaat on 24 April.
The consortium - comprising Van Oord, BAM, and Rebel, has recently been contracted to design and build the enforcement of the dam by 2022. The consortium will also be responsible for the maintenance for 25 years. The net value of the public-private partnership (PPS) project is 550 million euro.
|The current surface of the seaside bank consists of grass. The new planned facing with the Levvel-blocs will allow waves to overtop the dam and will make it climate proof for the next 50 years.|
Wave retardant effect
On the Wadden Sea side, the closure dam and causeway Afsluitdijk, will be raised and reinforced with new facing (see impression on top photo). For this work, the consortium will use ‘Levvel blocks’, innovative concrete elements that have been developed specially for the Afsluitdijk.
Each block weighs about 6,500 kg, is extremely strong, has a wave retardant effect, and is easy to install. It will also contain wholes for sea life to seek shelter and for plant roots to grow in.
Each block is to be equipped with a sensor to monitor the status of the dam as flood defence, and to access the required maintenance.
|The first Levvel-block has been presented. 74,999 to follow.|
Some 100 blocks a day will be produced by means of a fully automated process in the port of Harlingen and transported by ship to the causeway. A pontoon crane will then be used to position the blocks, 75,000 in all.
Because of their symmetry and the regular way they are positioned, the blocks have a tranquil appearance that reinforces the austere and autonomous character of the causeway.
Expanded locks and fish passage
Next to the enforcement of the Afsluitdijk the current two drainage locks will be expanded. Levvel will also build two large solar-powered pumping stations.
A real novelty will be a fish migration river to allow migration from the Wadden Sea (salt water) to the IJssel lake (fresh water). This will be a 4 km long channel surrounded by an ecological area accessible to visitors.
Levvel will construct the necessary opening in the Afsluitdijk for the fish migration river.
Read also on this website
● Joint venture Levvel preferred bidder for reinforcement closure dam Afsluitdijk, the Netherlands, 26 February 2018
● Ambitious 850 million reinforcement will make the Afsluitdijk a new icon of Dutch flood protection, 15 May 2015
● Expertise: Enabling delta life
● Country: The Netherlands
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Video impression of the reinforcement works by the Levvel consortium during the next four years.