Editing Canal (section)

{{Short description|Artificial channel for water}}
{{Other uses}}
{{Use Oxford spelling|date=September 2016}}
{{Use dmy dates|date=September 2020}}
{{More citations needed|date=February 2025}}

[[File:Alter Strom.jpg|thumb|The Alter Strom, in the sea resort of [[Warnemünde]], Germany]]
[[File:IMG RoyalCanalnrKinnegad5706w.jpg|thumb|The [[Royal Canal]] in [[Republic of Ireland|Ireland]]]]
[[File:Basingstoke Canal - Lock.JPG|thumb|Small boat canals such as the [[Basingstoke Canal]] fuelled the Industrial Revolution in much of [[Europe]] and the [[United States]].]]
[[File:Ponte_sul_Naviglio.jpg|thumb|right|Bridge on the [[Naviglio Grande]], in the town of [[Cassinetta di Lugagnano]], in [[Italy]]]]
[[File:Broek in Waterland, woonhuis aan het Ee.jpg|thumb|Canal in [[Broek in Waterland]], Netherlands]]
[[File:Wenecja, kanał wodny (Aw58TF).jpg|thumb|Canal in [[Venice]]]]

'''Canals''' or '''artificial waterways''' are [[waterway]]s or [[river engineering|engineered]] [[channel (geography)|channel]]s built for [[drainage]] management (e.g. [[flood control]] and [[irrigation]]) or for conveyancing [[water transport]] [[watercraft|vehicle]]s (e.g. [[water taxi]]). They carry free, calm surface flow under [[atmospheric pressure]], and can be thought of as artificial [[river]]s.

In most cases, a canal has a series of [[dam]]s and [[lock (water transport)|locks]] that create [[reservoir]]s of low speed current flow. These reservoirs are referred to as ''slack water levels'', often just called ''levels''. A canal can be called a '''navigation canal''' when it parallels a natural river and shares part of the latter's [[discharge (hydrology)|discharge]]s and [[drainage basin]], and leverages its resources by building dams and locks to increase and lengthen its stretches of slack water levels while staying in its [[valley]].

A canal can cut across a [[drainage divide]] atop a [[ridge]], generally requiring an external water source above the highest [[elevation]]. The best-known example of such a canal is the [[Panama Canal]].

Many canals have been built at elevations, above valleys and other waterways. Canals with sources of water at a higher level can deliver water to a destination such as a city where water is needed. The [[Roman Empire]]'s [[aqueduct (bridge)|aqueduct]]s were such [[water supply]] canals.

The term was once used to describe linear features seen on the surface of [[Mars]], ''[[Martian canals]]'', an optical illusion.