Maeslant Barrier
The Maeslant Barrier is the last major project of the Delta Plan.
The Maeslant Barrier can close off the Nieuwe Waterweg at Hook of Holland. The barrier absorbs the first impact from the sea during high water, protecting the Hartel Barrier and the Hollandsche IJsselkering. No other water barrier in the world has larger movable components than this Delta Work.
The Maeslant Barrier in statistics
- Built between 1991 and 1997
- 420 metres long
- Two gates, each 210 metres wide, 22 metres high, and 15 metres deep
- Ball hinges with a diameter of 10 metres and a weight of 680 tonnes
- Can withstand a storm surge of 5 metres above sea level
- Protects over 2 million Dutch people
- Closes within 2 hours
Origin
The Maeslant Barrier was not part of the original Delta Plan. That plan assumed that the Nieuwe Waterweg would always remain open for shipping to Rotterdam and Antwerp. However, new calculations showed that the dikes along the Nieuwe Waterweg were not high enough, and raising the dikes would come at the expense of existing buildings and cultural heritage.
Therefore, an alternative solution was considered to ensure that the Port of Rotterdam remained accessible. This involved a combination of dike reinforcement near Rozenburg and two movable barriers: the Maeslant Barrier and the Hartel Barrier. The Maeslant Barrier absorbs the first impact from the sea, and the Hartel Barrier prevents seawater from flowing inland via the Hartel Canal.
Construction
Unlike the other Delta Works, the Maeslant Barrier was not constructed by Rijkswaterstaat. Instead, a competition was held for the best design. The barrier had to close at 3 meters above sea level but could not close more than once or twice every 10 years. The design also had to avoid narrowing the shipping route and should not impose any height restrictions on ships. Therefore, a barrier with descending sluices, like the Hollandsche IJsselkering and Hartel Barrier, was not an option.
The design competition was won by Bouwkombinatie Maeslantkering. This consortium of companies developed two massive 'gates' that can be rotated into the water using powerful motors from the shore. These barriers are 210 meters long – nearly twice the height of the Dom Tower in Utrecht – and are anchored to the shore with a giant ball hinge weighing 680 tons and a diameter of 10 meters.
The barriers are essentially two floating, hollow pontoons, which are brought into place empty. They are then filled with water to create solid barriers. When the barrier needs to open again, the gates are pumped empty and rotated back. They then float into a dry dock to prevent rust and allow for easy maintenance.
In 1991, Bouwkombinatie Maeslantkering began construction, and six years later, Queen Beatrix officially commissioned the barrier. The Maeslant Barrier cost nearly half a billion euros.
A visitor centre was also opened. The annual test closure, held on a Saturday at the end of September, still attracts a lot of attention.
