Summit level canal

A summit level canal is an artificial waterway connecting two separate river valleys. It was an essential step in developing transport systems connecting different parts of a country before the railways or modern road transport.

The first canal to connect rivers across a watershed was the Lingqu (Magic Canal) in China which connected the Xiang and Li rivers in 219 BCE for military transport. However this is not usually considered a summit level canal as the summit level was a flat cut and there were originally no locks, although lateral canals with locks were added later on the two rivers.

The honour for the first summit level canal therefore goes to the Grand Canal of China. This was started in the 4th century BCE with major extensions in 329 CE, but it is the rebuilding and extension in the Sui Dynasty (581-617 CE) [ [http://www.icomos.org/studies/canals3.htm The International Canals Monuments List] ] that connected the Yangtse and Yellow rivers that established it as such. It used single locks until the tenth century when pound locks were introduced and it remained into the modern era as the longest canal in the world at 1145 miles.

In Europe, the first summit level canal was the Stecknitz Canal in Germany which connected the Stecknitz river to the Delvenau, a tributary of the Elbe, as part of the old salt route. It used 15 staunches and a summit level of 13km and the millers only opened the flash locks on alternate days.

The first to use pound locks was the Briare Canal in France which was completed in 1642. This 55km 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 with its 5km feeder supplying the summit levels from a reservoir (Étang de la Gazonne), a 7 flight riser on the northern side and 41 masonry locks in all..

But the greatest engineering feat of the 17th century was the Canal du Midi in Southern France, joining the Garonne, which drains into the Atlantic Ocean to the Étang de Thau which leads to the Mediterranean and was opened in 1684. Its 240km length rises 62.8m from the western end and falls 190m to the east with 103 locks, a tunnel and three major aqueducts. To solve the water supply problem, the engineer Pierre-Paul Riquet constructed a major dam in the Black Mountains and constructed a feeder canal about 40km long. [L.T.C. Rolt. "From Sea to Sea". Allen Lane 1973. Euromapping 1994]

The industrial revolution brought about a huge network of canals in England and other European countries which made summit levels a commonplace. But it took until the end of the 19th century and into the 20th before the great ship canals such as the Kiel Canal and Panama Canal joined different seas and oceans together.

List of major summit level canals

China
*Grand Canal
*Lingqu Canal

France
*Briare Canal
*Canal du Midi
*Canal du Rhône au Rhin
*Canal du Centre

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

United States
*Chesapeake and Delaware Canal

Panama
*Panama Canal

References