Editing Canal (section)

==Construction==
Canals are built in one of three ways, or a combination of the three, depending on available water and available path:
;Human made streams
* A canal can be created where no stream presently exists. Either the body of the canal is dug or the sides of the canal are created by making [[levee|dykes or levees]] by piling dirt, stone, concrete or other building materials. The finished shape of the canal as seen in cross section is known as the ''canal prism''.<ref>{{cite web|last1=Thompson|first1=Kristi|title=Glossary|url=https://www.usbr.gov/library/glossary/#C|website=www.usbr.gov|publisher=US Bureau of Reclamation|access-date=15 September 2017|language=en}}</ref> The water for the canal must be provided from an external source, like streams or reservoirs. Where the new waterway must change elevation engineering works like locks, lifts or elevators are constructed to raise and lower vessels. Examples include canals that connect valleys over a higher body of land, like [[Canal du Midi]], [[Canal de Briare]] and the [[Panama Canal]].
* A canal can be constructed by dredging a channel in the bottom of an existing lake. When the channel is complete, the lake is drained and the channel becomes a new canal, serving both drainage of the surrounding [[polder]] and providing transport there. Examples include the {{Interlanguage link multi|Lage Vaart|nl}}. One can also build two parallel dikes in an existing lake, forming the new canal in between, and then drain the remaining parts of the lake. The eastern and central parts of the [[North Sea Canal]] were constructed in this way. In both cases pumping stations are required to keep the land surrounding the canal dry, either pumping water from the canal into surrounding waters, or pumping it from the land into the canal.
;Canalization and navigations
{{anchor|Canalization|Navigation|Navigations}}
* A stream can be ''[[River engineering#Canalization of rivers|canalized]]'' to make its navigable path more predictable and easier to maneuver. Canalization modifies the stream to carry traffic more safely by controlling the flow of the stream by dredging, damming and modifying its path. This frequently includes the incorporation of locks and spillways, that make the river a navigation. Examples include the [[Lehigh Canal]] in [[Lehigh Valley|Northeastern Pennsylvania]]'s [[coal Region]], [[Basse Saône]], [[Canal de Mines de Fer de la Moselle]], and canal [[Aisne (river)#Canalized portion|Aisne]]. [[Riparian zone restoration]] may be required.
{{anchor|Bypass canal|lateral canal}}
;Lateral canals
* When a stream is too difficult to modify with ''canalization'', a second stream can be created next to or at least near the existing stream. This is called a ''[[lateral canal]]'', and may meander in a large horseshoe bend or series of curves some distance from the source waters stream bed lengthening the effective length in order to lower the ratio of rise over run (slope or pitch). The existing stream usually acts as the water source and the landscape around its banks provide a path for the new body. Examples include the [[Chesapeake and Ohio Canal]], [[Canal latéral à la Loire]], [[Garonne Lateral Canal]], [[Welland Canal]] and [[Juliana Canal]].

Smaller transportation canals can carry [[barge]]s or [[narrowboat]]s, while [[ship canal]]s allow seagoing ships to travel to an inland port (e.g., [[Manchester Ship Canal]]), or from one sea or ocean to another (e.g., [[Caledonian Canal]], [[Panama Canal]]).