Eider Barrage
The Eidersperrwerk is located at the mouth of the Eider in the North Sea at Tonning in Schleswig -Holstein. Main purpose of the barrage is to protect against storm surges in the North Sea, it is the largest German coastal protection structure. Also, the construction project under the North program for economic recovery in the circles should Norderdithmarschen (now part of the circle Dithmar ) (now part of the district of North Friesland ) contribute and eiderstedt. As a project of the century, the locking mechanism was inaugurated on 20 March 1973.
After 1962, the Hamburg storm surge also gripped Tonning, you wondered if you should increase the dikes on the Eider shore or build a barrage at the mouth. They opted for the latter, in 1967, work began. Great difficulties were preparing the flow conditions at the mouth, when costs were correspondingly high (about 170 million DM = about 87 million euros ). The dike line in the Eider range was reduced from 60 km to 4.8 km. The changed flow conditions were digging in the following years, however, up to 28 meters deep scour holes on both sides of the barrage, which had to be filled in 1993 with 45,000 sandbags.
Execution
The locking mechanism consists of two separate rows, each with five gates. The plant was designed to provide a dual safety dike. Between the gates leading through a street, protected by a 236 meter long tunnel. Above the tunnel is a walkway that offers a good view of the west coast and the Eider. Also performed with double gates is a the barrage Affiliate lock vessel traffic on the river Eider. Together with the also newly built dike, the locking mechanism is 4.9 kilometers long, is 8.5 meters above sea level and 7 meters above mean high tide level. Five Sieltore of 40 meters in length, let the water flow into the North Sea at low tide the Eider Eider water in the North Sea and at high tide. In addition, a 75 meter long and 14 meter wide chamber lock, come by the ships out of the harbor adjacent to the North Sea.
Operation forms
The locking mechanism is the prevailing weather conditions and announced according to moved in four different types of operation to ensure the hinterland optimal protection against the vagaries of the North Sea.
- Normal operation
In the operational form normal operation, all doors are open. The water, Eider and North Sea water can flow freely in both directions.
- Normal operation with flood throttling
Sea water flows out of the North Sea coming in the Eider. In order to reduce the sand entry into the Eider the seaward gates are partially lowered.
- Storm surge operation
From a water level above one meter above mean high tide both Torreihen are closed. This is done for reasons of a double dyke safety.
- Sielbetrieb
For the Sielbetrieb only the offshore Torreihe is closed during the flood period, so that the water from the North Sea can not penetrate into the Eider. With falling North Sea level after a flood, during low tide time, these open for drainage of the hinterland.
Normal operation with flood throttling
Storm surge operation
Sielbetrieb
Further use
Today, the building also serves as a destination for tourists on their way to eiderstedt with the seaside resorts of St. Peter- Ording, Vollerwiek or excursion Garding. Numerous fishing boats moved from Tonning to return to the fishing port located at the barrage, as the way to the fishing grounds were much shorter.
Nature
The construction of the barrage was built in the previous Eider estuary nature reserve Katinger Watt, on the other side of the river in 1989, the nature reserve Dithmarsch Eider Watt was reported to at least partially compensate for the loss of salt marshes and tidal flats by the Sperrwerksbau. At the barrage itself breeds a larger colony of terns with 143 station pairs in 2006.
Trivia
On barrage in the final sequence of Wim Wenders' film is The American Friend of 1977.