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Schematic representation of a culvert to cross a canal
Pressure pipe of an open irrigation channel for crossing under a path

A culvert ( low German corresponds Dutch duiker , "diving") is a pressure line for passing under a road, a tunnel , a river or railroad tracks, etc. The tube for example, a gas, waste water or drinking water pipe or oil pipeline or be These are so-called open culverts that lead groundwater or open bodies of water (drainage ditches, brooks and rivers) under rivers, roads or other structures. When laying cables under rivers, one also speaks of a cable culvert. There are also culverts that can be accessed by personnel in which various media (gas, water, electrical) are laid.

A culvert to cross a valley, as the Romans built from lead and clay pipes, is more commonly called a siphon . The counterpart to a culvert is the jack that is built for crossing.


In the culvert, the liquid can overcome the obstacle without the need for pumps. The principle of communicating tubes is used , according to which liquids in interconnected tubes always level themselves at the same level. If new liquid is constantly flowing in on one side, it reaches the same height level on the other side and can be passed on there with almost no loss of height.

With a simple passage , the water level goes freely to the other side. A passage runs empty when no more water arrives. A culvert, on the other hand, is lower than the drain and may have to be pumped out. The half culvert is considered an interim solution. The bottom of the pipe is deepened in relation to the inflow, but the top of the pipe is always above the liquid. A real culvert is always designed as a pressure pipe.


Various construction methods are used to build a culvert to cross a river through a pipeline .

When building in an open trench, a trench is first dredged across the river bed. If the river or shipping canal is delimited with a sheet pile wall, the steel culvert, which is pre-assembled in three parts on land, is integrated watertight, the ascending or descending branch can then be screwed or welded on. If the water is limited by embankments, the one-piece steel culvert is either loaded onto a pontoon and laid by crane at the point of use, or it is swum in directly from land by crane. Finally, a sand-gravel mixture is washed into the prepared culvert bed so that the cover layer protects it against damage from watercraft (e.g. when throwing an anchor). The inlet and outlet structures are then added.

Another type of construction is the tunneling method, usually in shield tunneling . Here a start and target pit are built, which later usually also serve as an inlet and outlet structure. From the starting pit, the tunneling machine digs its way under the water to the target pit. The corresponding concrete culvert pipe is pushed in immediately so that the finished culvert is created behind the machine.


Illustration to mark culverts on waterways

Culverts on waterways are marked by a square picture board with a D, with the writing facing the waterway. In other cases, the labeling is inconsistent. Boards with the word culvert are often set up, which can be read from the land side.

Avoidance of deposits

Production of a wooden ball for cleaning the Dresden Elbe culvert

In culverts, which are used to pass sewage under an obstacle (river, tunnel), the culvert usually has a smaller cross-section (about 10–20%, depending on the normal pipe cross-section) than the pipe arriving at the top of the culvert and leaving the bottom of the culvert to increase the flow velocity (in this case about 2 m / s) in the culvert so that no substances can settle in the culvert bottom that could block the culvert. However, as is often the case with rivers, the problem is that the quantities can fluctuate by more than a hundred times (rainy weather). This is why several pipes are often laid in parallel and charged depending on the amount of water. Since the system cannot be regulated, deposits occur - especially in the case of water that is heavily contaminated with suspended matter - which must be removed at great expense.

Air cushion culvert

Air cushion culverts are culverts whose cross-section can be adapted to the water inflow in order to keep the flow velocity constant. It consists of a horizontal pipe with vertical inlets. The inlet and outlet of the culvert are limited by a siphon so that air can be pumped into the culvert. This air cannot escape and reduces the cross-section of the culvert. If little water flows into the culvert, it is a large air cushion that makes the cross-section very small; if more water comes in, the amount of air is reduced and the cross-section enlarged. In this way, a constant flow rate of the water is achieved. The Hamburg municipal drainage system works according to this system on a culvert that connects Hamburg's northwest under the Elbe with the Köhlbrandhöft Nord sewage treatment plant . The air-cushion culvert at Wiener Platz in Dresden has the world's largest operating range of a minimum of 10 l / s and a maximum of 8800 l / s, i.e. 1: 880 .

Again and again the claim emerges that the disadvantage of this system is that the air cushion pushes the culvert upwards (buoyancy) and the culvert must therefore be very heavy or have heavy foundations in order not to float up. This is not true. It is true that the air actually generates buoyancy, but on the one hand this is counteracted by the reinforced concrete pipe itself, and on the other hand the passive earth pressure is activated so that no additional foundations are required. This would cause manufacturing problems, especially when driving pipes.


Culvert canal of the Wakenitz in Lübeck
Culvert of the Schmalen Gera (back) under the flood ditch (front) from 1895 in Erfurt . The outlet on the other side is not shown.
Lock entrance with under-roofing and overflow into the trench running below on the south-north canal
  • In Koblenz , the 370 m long Rhine culvert connects the old town with the Ehrenbreitstein district . The culvert, built in 1979–1982, lies 16 m below the river bed of the Rhine and is used for water supply and disposal.
  • District heating culverts (2 times DN 400) through the Traisen for the Dürnrohr St. Pölten heat transport line
  • A culvert pipe connects the water intake tower with the Heinrich Geis tunnel on the opposite bank of the Kalltalsperre in the northern Eifel.
  • The Elbe culvert on the Flügelweg in Dresden has been used since 1907 to channel the wastewater from the old town on the left Elbe under the Elbe into the Dresden-Kaditz sewage treatment plant on the right . It consists of a pipe with a diameter of 105 cm, the dry weather pipe, which is continuously flown through, and a pipe with a diameter of 200 cm, the rain weather pipe, which absorbs the larger amounts of water that arise in rainy weather. The double culvert crosses under the Elbe over a length of 117 m. Including the inlet and outlet sections, the culvert is 300 meters long and is delimited by two structures, the culvert chambers. Once a year a diver has to clean the culvert.

In Schwäbisch Hall , a power station canal, which branches off to the left several 100 m above the Kocher (at Alter Spinnerei), crosses the same river in the district of Gelbingen, and then after a short further canal section in a tunnel to cross under the Neuberg northwards to drive a small power station there . The cooker describes a wide meander counterclockwise around the incomplete Umlaufberg Neuberg. The buildings date from the 19th century.

See also

Web links

Commons : culvert  - collection of images, videos and audio files
Wiktionary: Düker  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. a b Air cushion culvert on Wiener Platz in Dresden (PDF, 276 kB) ( Memento of the original from August 25, 2006 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  2. Koblenz tunnel "Rheindüker": data / facts and Hofmann-Göttig with local politicians on the way through the "Rheindüker" .
  3. Detailed construction report of a culvert on pages 32 to 42: Andreas Oberhammer: The longest district heating pipe in Austria. Report on planning, construction and quality assurance; Association of gas and heat supply companies; March 2010 ( Memento of July 6, 2011 in the Internet Archive ) (PDF, 15.4 MB); As of April 2, 2010.
  4. ^ Sächsische Zeitung: A new age of canals begins on March 8, 2010.
  5. ^ Sächsische Zeitung: Diving into the canal on May 13, 2006.
  6. On the construction of the Neunzehnhain-Einsiedel water pipeline . In: Industry of the Ore Mountains and Vogtland . XIX edition. Organ of the Erzgebirger Association of Dresden, 1907, p. 199 ( online [accessed August 21, 2009]).
  7. Official Journal Frankfurt / Main (February 23, 2010 / No. 8, 141st year) page 7 of 16; Management report 2011 of the company Stadtentwässerung Frankfurt am Main.