Maeslantkering
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The Maeslantkering is a storm surge barrier in the Nieuwe Waterweg waterway located between the towns of Hoek van Holland and Maassluis, Netherlands, which automatically closes when needed. It is part of the Delta Works.
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The Maeslant Barrier
The initial plan
The construction of the Maeslantkering was a part of the "Europoortkering"-project which, in turn, was the final stage of the Delta Works. The main objective of this Europoortkering-project was improving the safety against flooding of the Rotterdam harbour, of which the Europoort is an important part, and the surrounding towns and agricultural areas. This had to by carried out by the reinforcement of existing dikes as far as 50 kilometers inland. During the 1980s it became clear that this project would take at least 30 years and would cost a huge amount of money. It would also mean that historic town centres, sometimes built more than four centuries ago, had to be broken down and rebuilt behind renewed, larger dikes.
Therefore the initial plan was put aside and the Ministry of Waterways and Public Works organised a competition in which construction companies could make plans for the construction of a reliable but yet relatively cheap storm surge barrier.
The storm surge barrier
This storm surge barrier had to be located in the Nieuwe Waterweg waterway. This played an important role in the planning stage of the construction, as this waterway is the main route to the port of Rotterdam, the world's second largest port. Therefore a barrier like the Dutch Oosterscheldekering and the Thames Barrier could not be constructed, as such a barrier would block the shipping route.
The plan that provided in the construction of two large floating gates on both levees of the waterway, won the competition. The major advantage of this plan was the fact that the construction of the storm surge barrier could take place under dry conditions, in dry docks. Other advantages were the facts that no vital parts of the barrier had to be placed under water and maintenance of the barrier would be easy because of the dry docks. And, of course, there would be almost no inconvenience for passing ships.
Construction of the barrier
The construction of the barrier started in 1991. First the dry docks were constructed on both shores and a sill was constructed at the bottom of the Nieuwe Waterweg. Then the two 22 meter high and 210 meter long steel gates were built. After this, 237 meter long steel trusses were welded to the gates. Standing upright, these arms would be as high as the Paris Eiffel Tower, but each one weighs four times more than the Eiffel Tower. The main purpose of the arms is transmitting the immense forces, exerted on the gates while closed, to one single joint at the rear of each gate. During the closing or opening process, this ball shaped joint gives the gate the opportunity to move freely under the influences of water, wind and waves. It acts like the ball shaped joint between a human’s arm and shoulder. After six years of construction the storm surge barrier was finished.
Maeslantkering in operation
At May 10, 1997, Queen Beatrix opened the Maeslantkering. From that moment the barrier is in full operation. The barrier is connected to a self-operating computer system which is linked to weather and sea level data. When a storm surge of 3.00 meter above normal sea level is anticipated in Rotterdam the barrier will be closed automatically. Four hours before the actual closing procedure will begin, in and out going ships are warned. Two hours before closing the traffic at the Nieuwe Waterweg will come to a stand still. Thirty minutes before closing the dry docks that bear the gates are inundated. After this the gates start to float and two so called "locomobiles" will move both the gates towards each other. When the gap between the gates is about 1.5 meter wide, the gates are submerged to the bottom of the waterway, thus protecting the inland. Under normal weather conditions the two doors themselves are well protected in their dry docks and a 360 meter wide gap in the waterway gives ships enough space to pass without any inconvenience.
The Maeslantkering is expected to be closed once every ten years due to a storm surge. With the rise in sea levels the storm surge barrier will need to close more frequently in 50 years time, namely once every five years. Until this date the barrier had never been closed due to a storm. The barrier is closed for testing once a year, usually in September or October, just before the beginning of the storm season in November.
The Calandkanaal (Caland canal), located just south of the Nieuwe Waterweg and visible in some images on this page, is protected by the much smaller Hartelkering storm surge barrier. This barrier is constructed some 5 kilometers further inland.
Trivia
- The construction of the barrier cost 450 million Euro. The total Europoortkering-project had cost 660 million Euro.
- The barrier is designed to withstand storms that would occur only once every 10,000 years (based on the climate at the time, but this may have to be adjusted for the climate change).
- The ball shaped joint is the largest in the world: diameter 10 meter, weight 680,000 kg.
- A working 1:250 scale version of the barrier was constructed in the Madurodam miniature village. Its construction took six months instead of the six years for the real barrier.
- The barrier was last tested at October 1, 2005. It worked perfectly.
- The visitors centre "Keringhuis", built next to the barrier is opened Tuesday to Sunday.
- The barrier was featured on the US television program Extreme Engineering.