02 MSL Storm Surge Barrier

Maeslant storm surge barrier

No other flood barrier in the world has larger moveable parts than the Maeslant storm surge barrier. This part of the Delta Works can withstand a storm tide of 5 metres above NAP.

The Maeslant barrier is located in the Nieuwe Waterweg near Hoek van Holland and was built between 1991 and 1997. The structure is operated entirely automatically and, together with the Hartel barrier and the expanded Rozenburg dike, forms the Europoort storm surge barrier. The Maeslant barrier is a forward flood surge barrier, which means that it receives the full brunt of flooding from the sea and so protects the residents of the province of Zuid-Holland.

The Maeslant storm surge barrier:

210 m
is the width of each door of the Maeslant barrier
  • was closed for the first time in 2007
  • has two doors, each 210 metres wide, 22 metres high and 15 metres deep. When the barrier closes, they fill with water and sink to the bottom within two hours
  • operates with ball-and-socket joints, each of which is 10 metres in diameter and weighs 680 tonnes
De Maeslantkering houdt de vaarroute helemaal open, ondanks zijn enorme afmetingen.

When does the barrier close?

The Maeslant storm surge barrier closes if the water level is predicted to rise to more than 3 metres above NAP near Rotterdam or more than 2.9 metres above NAP near Dordrecht. The closure of the barrier and the decision to close it both occur fully automatically. In principle, no human intervention is required. Nevertheless, if flooding is expected, an operational team from Rijkswaterstaat is always on hand to monitor the automatic process and to intervene manually if necessary.

What does Rijkswaterstaat do?

Rijkswaterstaat manages and maintains the Maeslant storm surge barrier. Using a specially developed model we carry out analyses to calculate the risk that the barrier will refuse to close and test, inspect, repair and if necessary replace parts on the basis of those calculations.

The Maeslant storm surge barrier closes fully automatically.


The Maeslant storm surge barrier was not a part of the original Delta Plan, but its design is just as ingenious and massive as the other structures in the Delta Works. Prior to its construction, an independent committee, in close consultation with Rijkswaterstaat, the municipality of Rotterdam and the water board, investigated four variants. The committee assessed the length of time the design would take to build, the costs and the consequences for the business community. It also assessed which variant would blend most effectively into the landscape.