View source for Summit-level canal

{{Short description|Artificial waterway between watersheds}}
[[Image:Canal du Midi 02.jpg|thumb|right|300px|[[Canal du Midi]]]]
A '''summit-level canal,''' sometimes called a "watershed canal" or just "summit Canal", is an artificial waterway connecting two separate river valleys. The term refers to a canal that rises to cross a summit then falls down the other side.<ref name="brittanica-Canal"/>
Typically, summit-level canals include a  [[Canal_pound#Summit_pound|summit pound]], a level stretch of water at the highest part of the canal, usually contained by locks that prevent the water from flowing downstream in either direction. Since water flows out when locks open to admit boats, the summit pound must have a water supply.
By contrast, a ''lateral canal'' has a continuous fall only.<ref name="brittanica-Canal">{{cite web|title=Canals and inland waterways|url=http://www.britannica.com/technology/canal-waterway|website=Encyclopædia Britannica|access-date=10 June 2016}}</ref>
Summit-level canals were an essential step in the extension of transport systems before the development of railways and modern highways.{{fact|date=October 2021}}
==History==
The first canal to connect rivers across a watershed was the [[Lingqu Canal]] ("Magic Canal") in China which connected the [[Xiang river|Xiang]] and [[Li River (Guangxi)|Li river]]s for military transport.  Construction began in 223 BCE and the canal was in use by 214 BCE.  <ref name=":0" > [Needham, Joseph and Wang Ling  '''''Science and Civilisation in China''''', Part 3 “Civil Engineering and Nautics” of Volume IV “Physics and Physical Technology” (Cambridge University Press, Cambridge, 1971)  Library of Congress Card Number 54-4723 pp 299 & ff ]  </ref>  The Lingqu carried boats and barges over a 30-meter high summit at an elevation of 210 meters, connecting the Yangtze River watershed with the Pearl River watershed.  The Lingqu facilitated the unification and creation of China under its first emperor Qin Shi Huangdi.
A second Chinese summit-level canal was the [[Grand Canal of China]].<ref name=":1">[http://www.icomos.org/studies/canals3.htm The International Canals Monuments List] {{Webarchive|url=https://web.archive.org/web/20070927004657/http://www.icomos.org/studies/canals3.htm |date=27 September 2007 }}</ref> This was started in the 4th century BCE with major extensions in 329 CE,  But it was the rerouting of the canal in the 1280s to shorten the connection to the new capital [[Beijing]] at the start of the [[Yuan dynasty]], crossing the [[Yangtze]] and [[Yellow River]]s, that established it as a summit-level canal. It remained into the modern era as the longest canal in the world at {{convert|1145|mi|km}}.
In Europe, the first summit-level canal was the [[Stecknitz Canal]] (1390–1398) in Germany which connected the Stecknitz river to the [[Delvenau]], a tributary of the [[Elbe]], as part of the [[Old Salt Route]]. It used fifteen [[Flash lock|staunch]]es and had a {{convert|13|km|mi|adj=on}} summit level; the millers only opened the [[flash lock]]s on alternate days.
The first summit canal to use pound locks was the [[Briare Canal]] in France which was completed in 1642. This {{convert|55|km|mi|adj=on}} canal connected the [[Loire]] valley to that of the [[Seine]] to carry the agricultural produce of the Loire to Paris. In many ways it is the ancestor of all modern summit-level canals being fed from its reservoir, [[Étang de la Gazonne]].<ref name='rolt'/>
One of the greatest engineering feat of the 17th century was the [[Canal du Midi]] in Southern France opened in 1684, joining the [[Garonne]], which drains into the [[Atlantic Ocean]] to the [[Étang de Thau]] which leads to the [[Mediterranean]]. Its {{convert|240|km|mi|adj=on}} length rises {{convert|62.8|m|ft}} at the western end and falls {{convert|190|m|ft}} to the east via 103 locks, one tunnel and three major aqueducts. To solve the water supply problem, the engineer [[Pierre-Paul Riquet]] constructed a major dam in the [[Montagne Noire|Black Mountains]] and constructed a feeder canal approximately {{convert|40|km|mi}} long.<ref name='rolt'>{{cite book | last = Rolt | first = L. T. C. | author-link = L. T. C. Rolt | title = From Sea to Sea | publisher = Ohio University Press | year = 1973 | isbn = 9780713904710}}</ref>
A large network of 18th- and 19th-cantury summit-level canals in England, France, and other European countries facilitated the Industrial revolution.
==List of major summit-level canals by continent==
===Asia===
;China
*[[Grand Canal of China|Grand Canal]]
*[[Lingqu Canal]]
===Europe===
'''France'''
*[[Canal de Briare]]
*[[Canal du Midi]]
*[[Canal du Rhône au Rhin]]
*[[Canal du Centre (France)|Canal du Centre]]
*[[Canal de l'Oise à l'Aisne]]
'''Germany'''
*[[Rhine-Main-Danube Canal]]
*[[Kiel Canal]]
'''England'''
*[[Trent and Mersey Canal]]
*[[Leeds and Liverpool Canal]]
*[[Grand Union Canal]]
*[[Kennet and Avon Canal]]
*[[Rochdale Canal]]
*[[Huddersfield Narrow Canal]]
*[[Oxford Canal]]
'''Northern Ireland'''
*[[Newry Canal]]
'''Scotland'''
*[[Caledonian Canal]]
*[[Crinan Canal]]
*[[Forth and Clyde Canal]]
'''Poland'''
*[[Augustów Canal]]
'''Russia'''
*[[White Sea – Baltic Canal]]
*[[Volga–Baltic Waterway]]
'''Sweden'''
*[[Göta Canal]]
===North America===
'''United States'''
*[[Chesapeake and Delaware Canal]]
*[[Erie Canal]]
*[[Morris Canal]]
'''Canada'''
*[[Rideau Canal]]
'''Panama'''
*[[Panama Canal]]
==See also==
*[[Contour canal]]
==References==
<references />
<br />
{{Use dmy dates|date=March 2017}}
[[Category:Canals]]
[[Category:Water transport infrastructure]]