Maeslant Barrier

Maeslant Barrier (1991-1997)

One year after the storm surge barrier in the Oosterschelde was operational, the Ministry of Transport and Water Management launched a competition for the construction of another storm surge barrier. Not in Zeeland, but in the canal Nieuwe Waterweg. This would eliminate the need to raise the dikes around Rotterdam and would not only protect the city, but also the areas at risk of flooding along the rest of the Nieuwe Waterweg.

First priority for the design of the storm surge barrier is that it must not impede shipping. Of the six entries, the plan submitted by Bouwcombinatie Maeslant Kering is the winner. The design: two curved steel doors that can be rotated into the water from their docks in the banks of the canal. The construction of the Maeslant Barrier starts in 1991.

Eiffel Tower

The Maeslant Barrier is almost as long as the height of the Eiffel Tower and weighs four times as much. The doors are each 240 meters long and, when the barrier is open, are ‘stored’ in 210 meters long docks along both banks. In case of a storm surge, the docks are filled with water and the hollow doors attached to gigantic cantilever support start to float. They are then pivoted into the water with the aid of a train.

Thanks to a ball-and-socket joint – similar to a human hip joint – the doors can move in all directions. Horizontally during turning into the canal and vertically when lowering into the water. The ball hinges have a diameter of ten meters and each weigh 680 tonnes.

Turning the steel doors inwards takes half an hour. When the two doors meet in the middle of the canal, valves are opened, allowing water to fill the doors and then, thanks to their weight, they lower themselves onto a concrete threshold at the bottom of the canal. In order to close the Nieuwe Waterweg completely, the doors must be precisely placed on the threshold.

In order to flush away any sludge on the threshold, the doors do not sink onto the threshold straightaway, but first hover slightly above it. As a result, the flow becomes so strong that the sludge is flushed away and the doors can rest on a clean threshold. All in all, completely closing the barrier takes about one hour.


350.000 strong men

During a storm surge the water batters against the steel doors with a force of 350 Meganewton, which is equivalent to the effort of 350,000 strong men lifting 100 kilos each. Thanks to their convex shape, the steel doors of the Maeslant Barrier are able to cope with those forces of nature. The flood defense is controlled by a computer, but is always under human supervision.

The Maeslantkering was officially  operational on 10 May 1997. The opening was performed by then Queen Beatrix. The construction of the barrier cost a total of 635 million Euros. That is an estimated 180 million cheaper than the alternative: strengthening and raising all dikes in the area. Together with Europoort Barrier (a dike from Rozenburg to the Maeslant Barrier) and the Hartel Barrier, the Maeslant Barrier forms a line of defense against extremely high water for Rotterdam and the surrounding area.