The Couzon is a river in the Loire department of France, a tributary of the Gier, which in turn is a tributary of the

Rhône The Rhône ( , ; Occitan language, Occitan: ''Ròse''; Franco-Provençal, Arpitan: ''Rôno'') is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and Southeastern France before dischargi ...

. A dam on the river, built to serve as a reservoir for the

Givors canal The Givors canal () was built between 1761 and 1781 to carry coal, other goods and passengers from Rive-de-Gier to Givors on the Rhône, running beside the river Gier (river), Gier. The canal was approved in 1760 and after many problems opened ...

, now provides drinking water to the town of

Rive-de-Gier Rive-de-Gier (, literally ''Bank of Gier (river), Gier''; ) is a Communes of the Loire department, commune in the Loire (department), Loire Departments of France, department in central France. In 2020, with a population of 15,086 inhabitants and ...

Geography

The Couzon drains a basin of at a mean altitude of . It rises in the

Pilat massif Mont Pilat or the Pilat massif is a mountainous area in the east of the Massif Central of France. Name The origin of the name "Pilat" is uncertain. The word may have a Latin origin (''Mons Pileatus''). Another legend says that the body of Ponti ...

at an altitude of about . The river is long. It runs through the communes of Pavezin,

Sainte-Croix-en-Jarez Sainte-Croix-en-Jarez () is a commune in the Loire department in central France. It is a member of Les Plus Beaux Villages de France (The Most Beautiful Villages of France) Association. Population See also *Communes of the Loire department ...

, Châteauneuf and

. Tributaries are the Ruisseau Boissieux, Grand Valluy and Ruisseau de Chamerle.

Dam

In December 1788 King

Louis XVI of France Louis XVI (Louis-Auguste; ; 23 August 1754 – 21 January 1793) was the last king of France before the fall of the monarchy during the French Revolution. The son of Louis, Dauphin of France (1729–1765), Louis, Dauphin of France (son and heir- ...

approved construction of a reservoir to supply water to the

in dry periods. François Zacharie, the canal's builder, had proposed a site for the reservoir high up near

Saint-Étienne Saint-Étienne (; Franco-Provençal: ''Sant-Etiève''), also written St. Etienne, is a city and the prefecture of the Loire département, in eastern-central France, in the Massif Central, southwest of Lyon, in the Auvergne-Rhône-Alpes regi ...

, but the chosen site was low down on the Couzon near

. This short-sighted decision ruled out the plan to continue the canal up to Saint-Etienne via the

Janon The Janon is a small river that rises in Mont Pilat in the Massif Central of France near to Saint-Étienne. It runs for through mostly built-up country to join the Gier (river), Gier at Saint-Chamond, Loire, Saint-Chamond. The valley of the Janon ...

and then down to the

Loire The Loire ( , , ; ; ; ; ) is the longest river in France and the 171st longest in the world. With a length of , it drains , more than a fifth of France's land, while its average discharge is only half that of the Rhône. It rises in the so ...

. The French Revolution (1789–1799) delayed the work, but construction of the ''Barrage de Couzon'' (Couzon Dam) was completed in 1811. The dam was operational by 1812. It was formally inaugurated on 23 September 1814 by the Comte d'Artois. The dam was modeled on the dam built at Saint-Ferriol for the Midi canal. It has an unusual structure. Three parallel walls are interconnected by buttresses and form the central core. This is thick and long. Earth banks on each side of the wall provide strength. On the upstream (reservoir) side the earth bank is high, and on the downstream side the bank is high. Two tunnels run through the embankment at the deepest points. The lower one follows the original course of the river, and is used to remove silt from the reservoir. The upper one has valves where it exits the reservoir. There are two spillways with a combined length of . The dam intercepts water from a basin of with an average elevation of . Initially the dam was capable of containing of water. Today the dam has a capacity of . In 1880, when the canal company went bankrupt, the dam was converted into a source of drinking water for the inhabitants of Rive-de-Gier. It delivers per second of water. The water serves 95% of the municipality of Rive-de-Gier, part of Châteauneuf, and since 2005 St-Martin-le-Plain and St. Joseph. As of 2010 19,678 people relied on the dam for water, as well as various industrial users such as Industeel.

Other uses

A stretch of below the dam is used for kayaking.

Gallery

File:Quartier Couzon RDG.jpg, Route de Couzon in Rive-de-Gier start of the 20th century File:Couz val 1.JPG, Reservoir of the Couzon dam in November 2008 File:Paysage Barrage Couzon.jpg, Country around the Couzon dam in August 2008

References

Citations Sources * * * * * * * * {{DEFAULTSORT:Couzon Rivers of France Rivers of Loire (department) Rivers of Auvergne-Rhône-Alpes