A dam on the river, built to serve as a reservoir for the Givors canal, now provides drinking water to the town of Rive-de-Gier.

The Couzon drains a basin of 34 square kilometres (13 sq mi) at a mean altitude of 550 metres (1,800 ft).

[2] In December 1788 King Louis XVI of France approved construction of a reservoir to supply water to the Givors canal in dry periods.

This short-sighted decision ruled out the plan to continue the canal up to Saint-Etienne via the Janon and then down to the Loire.

[9] The dam intercepts water from a basin of 27.4 square kilometres (10.6 sq mi) with an average elevation of 588 metres (1,929 ft).

[8] 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.