The Thiou, about 3.5 km long, is considered one of the shortest rivers in France. It is an effluent of Lake Annecy

Lake Annecy

Lake Annecy is a perialpine lake in Haute-Savoie in France .It is the second largest lake in France, after the Lac du Bourget, if the French part of Lake Geneva is excluded. It is known as "Europe's cleanest lake" because of strict environmental regulations introduced in the 1960s...

 and an affluent of Fier, which is in turn is a tributary of the Rhone

Rhône

Rhone can refer to:* Rhone, one of the major rivers of Europe, running through Switzerland and France* Rhône Glacier, the source of the Rhone River and one of the primary contributors to Lake Geneva in the far eastern end of the canton of Valais in Switzerland...

. The Thiou is considered one of the cleanest rivers in Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and a postcard of the city of Annecy

Annecy

Annecy is a commune in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France.It lies on the northern tip of Lake Annecy , 35 kilometres south of Geneva.-Administration:...

. The Thiou crosses the city forming small canals without which the city would not be often called the Venice of the Alps.

During the nineteenth century, the Thiou played an important role in manufacturing activities and provided the necessary energy to the industries that developed in the city of Annecy.