Canal

As a channel is called a watercourse with artificially made water bed. However, it can be like a channel expanded as a watercourse with a natural river bed that he is one of the channels; this was often the case in earlier times in the smaller vessel dimensions.

Description

It is mainly distinguished between channels for irrigation and drainage and canals for shipping, the shipping channels. However, there are also channels that serve other purposes or served, such as drinking water supply, the use of water power, the elimination of waste water, or diversion of water from a water body to another ( eg the Armenian Sevan, is in Germany derived, for example, over the Dahme- Umflutkanal flood from the upper Spree for Dahme ).

Channels that transport primarily water are flowing water channels. This also may include shipping channels. This is the case if they were built in the path of a river or ditch or replace all or part of their route and be regulated alongside the locks by weirs. Examples of this are in Germany the Finowkanal and the Landwehr Canal. In general, however shipping channels are still water channels. As a result of human smuggling and due to water withdrawals (eg, for public and industrial water supply to the West German shipping canals ) they can still have a low flow. Your water levels are regulated by sluices and pumping stations. There are also channels without any regulation.

A channel is excavated mostly from the natural soil using natural depressions and watercourses and is lower than the terrain. However, it can also be constructed on dams and thus lie above the surrounding terrain. Such sections can be secured by security gates to avoid in case of leaks or dam failures and flooding large water losses, such as the Dortmund -Ems Canal. A channel can channel bridges with other channels or rivers cross and run in tunnels through mountains. A channel can be a less than a meter wide canal to supply water to be as well as a more than 300 -meter wide channel for shipping.

Be distinguished from one channel is a congestion- controlled ( earlier and outdated: channelized ) flow. He remains flow even with the development of dams, such as the Main.

Canal in the city

In cities that are close to a flat sea coast, serve as channels of drainage and transport routes. The channels are limited mostly by vertical mounts or submit directly approach the houses.

Known for their channels are Venice ( see also Grand Canal ) and some cities in the Netherlands and Belgium with its canals, for example, Amsterdam and Bruges, and Friedrichstadt in Schleswig -Holstein. The Navigli of Milan joined sooner the city and the nearby rivers and lakes. Also Birmingham in England is to be mentioned here. Although no major rivers flow through Birmingham, the city is the hub of the Middle English Narrowboat Canal Systems ( Midlands ). Within the city limits there are channels with a total length of 60 kilometers. It is often claimed that Birmingham has more canals than Venice (though the city's area is also a lot bigger ).

In contrast to the Channel Fleet was in the water level was not originally regulated (for example, in Hamburg) by locks, but fluctuated with the tide.

In towns, the rivers are largely expanded like a channel. Some have also been misplaced or " shared ", such as the Danube and the Danube Canal in Vienna.

Channel on land

A channel can transport - today especially the shipping - used in former times also the transport of wood ( channel raft, drift ) or from peat ( Fehnkanal ). Other channels are used for loading and drainage, the use of water power (mills, power plants, factories channel), which of course combined uses are possible. So many channelized rivers be used as a transport route as well as for the production of hydroelectric power. Another important area of ​​application includes irrigation channels / Flood for irrigation and drainage channels / outfall for drainage (drainage).

Typing of navigable canals

Channels are divided into more or less long drainage sections called conversations in which the water is kept in each case at the same height between the channel levels. Channel levels are formed by locks or lifts that allow the ships to overcome the height difference between the channel conversations.

Abbreviation channel

The abbreviation channel or engraving is a stretch of river with artificial river bed, will be cut by one or more consecutive loops of a river and thus the shipping route is shortened. Examples of this can be found here:

  • Havel
  • Main channel
  • The headwaters of the Saône
  • Sluices at the Mittelweser
  • Weilburger shipping tunnel

Branch canal

The branch channel ( earlier and outdated: branch channel ) is a blind alley that connects a city or an industrial area off to a running channel. The water supply of the branch canal can be done via the main channel or through an opening out river which also contributes thus to the water supply of the main channel. Be mentioned here as examples:

  • Branch canal from the Canal des Vosges Epinal after
  • Branch canal from the Canal du Nivernais by Vermenton
  • Branch ducts from the Mittelland Canal to Osnabrück, Hildesheim and Salzgitter
  • Spoykanal from the Rhine to Kleve - Brienen

Side channel

A side channel is branched from a river starting, running largely parallel to it and flows downstream into the same. It replaces or supplements the river as a waterway. Along its route it can be supplied by tributaries with water. Examples are:

  • Ilmenau- side channel
  • Side of the river channel
  • Canal in the Loire
  • Side channel Horkheim

Another type of side channel branches off in the lower reaches of the river and flows into another water body, such as the following:

  • Elbe Lateral Canal
  • Elde - side channel
  • Ems - side channel
  • Moldova channel

If such channels open into a sea, they are covered under marine channels.

Connecting channel

A connecting channel connects two waters and can be carried out in three variants:

  • First option: if the mountain range that separates them, is weak connection between two different basin draining into rivers. The channel follows the contour lines and bypasses without or with few steps the ridge. Magic channel (China, 219 BC)
  • Fossa Carolina / Karlsgraben ( Germany, 793 )
  • Bridgewater Canal (England, 1761)
  • Canal de Saint- Quentin ( southern section )
  • Canal de la Sauldre
  • Second option: connection of rivers and canals Rothenseer channel ( Germany, Elbe - Mittelland Canal )
  • Pareyer connecting channel ( Germany, Elbe - Elbe - Havel Canal
  • Connecting channel Ruhr ( Germany, Ruhr - Rhein- Herne Canal )
  • Gieselau channel ( Germany, Eider - Nord -Ostsee-Kanal )
  • Nordhorner connecting channel ( Germany ), EMS Vecht channel Vechte - Nordhorn- Almelo - channel
  • Third option: connection of lakes Mecklenburgisches and Brandenburg Lake District

Watersheds channel

A watershed canal climbs in on rising and falling levels of a watershed between two waters. In addition to the challenge of selecting suitable terrain sections for the impoundments, the water supply must be secured in the rule. This requires, in many cases, to provide in the neighborhood of a network of watercourses and water reservoirs to compensate for the water loss due to smuggling. Examples are:

  • Grand Canal (China, 600, precursor ca 4th century BC)
  • Stecknitz channel ( Germany, 1398 )
  • Canal de Briare (France, 1642)
  • Canal du Midi (France, 1681)
  • Kennet and Avon Canal (England, 1810)
  • Rhine - Rhône Canal (France, 1833)
  • Ludwig-Danube- Main Canal ( Germany, 1845)
  • Mittelland Canal ( Germany, 1915/1938 )
  • Moskva ( Volga ) channel (Russia, 1937)
  • Volga - Don Canal (Russia, 1952)
  • Main -Danube Canal ( Germany, 1992)

Marine channel

The sea channel can occur in three variants:

  • Canal Saint -Louis on the Rhone estuary in Port-Saint -Louis -du -Rhône
  • Danube - Black Sea Canal in Romania, although the Danube Delta is navigable and the channel is just a shortcut to the Black Sea

Not every sea channel is, however, clear and unambiguous identification of these three categories, since some channels also fulfill several functions. For example, belonged to the New Waterway in Rotterdam since its construction to the first variant, meanwhile, but also to the second, because the old Maas arms are no longer navigable. The Royal Military Canal on the south coast circumnavigated on country side a cliff and leads 28 miles from Seabrook at Folkestone to Cliff End near Hastings.

History

Tunnels and canals for water supply have driven the Assyrians and Syrians through rocks and mountains. Sennacherib had BC build a minimum of 55 km long water channel for supply of Nineveh in the 7th century, with locks and a large aqueduct.

In Egypt began Pharaoh Neco II (r. 610-595 BC) with the construction of a, also known as Bubastis channel navigation canal between the Nile and the Mediterranean and the Red Sea, but probably only under the Persian king Darius I was completed in the year 498 BC. To 280 BC the Diadochenherrscher Ptolemy II Philadelphus ( 284-246 BC) to restore the channel and install a floodgate to the Red sea. This precursor of the Suez Canal fell in the 1st century BC, but was restored under the Roman emperor Trajan in the 2nd century AD. With restrictions on the channel until the late 8th century AD in use.

The largest ancient channel of the Middle East was the Nahrawan channel along the Tigris near Ctesiphon. He came from the 3rd century, was 400 km long and 122 m wide.

In China, probably from the 6th century BC native Hong Gou canal was the first man-made waterway. However, a more well-known technical performance was the Magic channel (Ling Qu ) from the time of Qin Shihuangdis by 219 BC, the two oppositely flowing rivers - Li and Xiang - subdued and bound them together. He was projected by Shi Lu, initially served the troops and supply the first channel, which was performed on uneven terrain along contour lines was (32 km long). The Chinese emperor channel is over 1700 km long and often 30 m wide with a height difference of about 42 m.

Dahme Flood Relief Canal Grand Canal (Venice) Gracht The Midlands Donaukanal Ruhlsdorf (Strausberg) Factory Canal pound Canal de Saint-Quentin Ruhr (river) Gieselau Canal Briare Canal Volga–Don Canal Aigues-Mortes Danube–Black Sea Canal History of the Assyrian people Necho II. Flash lock Nahrawan Canal Li River (Guangxi)
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