Maeslant barrage
The Maeslantkering is a storm surge barrier at the mouth of the Nieuwe Waterweg . It improves flood protection for around one million people in the Rotterdam area .
Surname
Maeslant is Old Dutch for Maasland , after the river Maas . The Dutch word Kering describes any flood protection system. In the technical language of coastal protection, there is also the phrase in German that the flood is "swept" through a barrage.
history
After the devastating flood disaster of 1953 with 1836 victims, the delta plan was developed to protect the area from Rotterdam to Antwerp with dams. The inlets should be closed and the coastline shortened in order to offer less attack surface for storm surges. The best construction known today was finally realized from several drafts. Never before has a barrage been built with such large moving parts. Since these are all on land, shipping traffic on the way to the port of Rotterdam is not affected.
The barrage was built by 600 workers from 1991 to 1997 and cost 660 million euros . The entire construction is made of three times as much steel as the Eiffel Tower in Paris . The two arc-shaped gates can be rotated around a ball joint with a diameter of 10 meters and a weight of 680 tons . The foundations of the camps are made of concrete. The arms, which connect the circular arc segments of the barrier gates with the swivel joints at the bearing points, have a length of 237 m and consist of three large, interconnected lattice girders made of steel tubes . The gates are 22 m high and 210 m long each. They were put together from a total of 18 individual segments that were welded together on ships in the water.
function
When the water level is normal , the gates are in dry docks on the banks of the Nieuwe Waterweg . Shipping can then pass unhindered. When a storm surge threatens, the docks are flooded. This causes the gates to float open. With two redundant five-cylinder hydraulic motors , the gates are swiveled around their pivot point in the middle of the Nieuwe Waterweg . There the gates are flooded and lowered to the bottom of the shipping route (−17 m NAP ). Shortly before the ground comes into contact with the ground, a strong current develops between the gates and the ground, which clears the foundation (−17 m NAP) of deposits and silt . The 22 m high gates close the 360 m wide Nieuwe Waterweg up to a height of 5 m above NAP.
In the middle of the two gates there is a gap of 1.5 m so that the gates do not collide in a storm. There are control centers on both sides of the barrier where computers automatically control the locking . Every ten minutes, a forecast of the water level for the next 24 hours is made.
The closure of the waterway takes exactly 2½ hours.
In the adjoining visitor center, the construction, function and effects of the barrage are explained. Satellite maps and a model that floods at the push of a button (pictured opposite) can also be seen.
Closing criteria
The closure is automatically initiated by computers as soon as they expect a water level of 3.00 meters above the Amsterdam Level ( NAP ) near Rotterdam and / or 2.90 meters above NAP near Dordrecht. This has not happened since it was commissioned in 1997.
As soon as there has been no closure under the above condition for seven years, the closure criterion is reduced in order to carry out a closure under the most realistic conditions possible, a so-called verification closure. The criterion for this is 2.60 m NAP in Rotterdam and / or 2.30 m NAP in Dordrecht. This criterion has occurred since its introduction on October 1, 2017 on January 3, 2018.
The first verification closure took place on the night of November 9, 2007, when the Tilo storm hit Central and Northern Europe. At the same time the Hartel barrier was closed. For Rotterdam only a level of 2.60 m NAP was expected.
The second verification closure took place on January 3, 2018. On this day, all five major storm surge gates in the Netherlands were closed simultaneously for the first time.
It is closed annually, regardless of the water level, in order to check the function. For example, this closure took place on September 9, 2017.
Web links
- Visitor Center website (Dutch, English)
- Website about the Delta Works (multilingual)
- Maeslant barrage. In: Structurae
Individual evidence
- ↑ NLWKN: Ems Barrage
- ^ Vegesack: Lesum barrage
- ↑ a b portofrotterdam.com
- ↑ rijkswaterstaat.nl (Dutch)
- ↑ ksta.de January 4, 2018
- ↑ rijkswaterstaat.nl liveblog January 4, 2018
Coordinates: 51 ° 57 ′ 14 " N , 4 ° 9 ′ 49" E