“Strategic reservoir”, “very concrete impacts”… How the flow of the Rhône has become a source of tension between Switzerland and France

Emmanuel Macron has been visiting Switzerland since Wednesday November 15. The Head of State was notably received in Bern: a rare trip for a French president and a sign of a warming up with Swiss diplomacy. Among the topics of discussion is water management, because with its 1,400 glaciers, Switzerland is like a water tower for Europe.

The Rhône has its source in the glacier that bears its name in Switzerland and then flows from Lake Geneva, before, finally, meandering to France, where the river empties into the Mediterranean. However, the Helvetii have the “hand on the tap” : “At the exit of Lake Geneva, there is this tap which is the Seujet dam which in fact defines the regulation of Lake Geneva, but which will therefore also have very concrete impacts on the quantity of water which is then sent to the lake. French territory”explains Christian Bréthault, professor in Geneva and co-director of the UNESCO hydropolitics chair.

The regulation of Lake Geneva has taken on “new importance”

Many strategic sectors depend on the Rhône, such as the cooling of nuclear power plants. And in 2011, the Bugey power station faced a drop in throughput. “We had come out of a winter with a little less snow and therefore the lake was below the levelsrecalls Christian Bréthault. As a result, Geneva decided to reduce the outflow to raise the lake, without necessarily prior consultation with France. This led to a cooling problem which never jeopardized nuclear safety, but which had an impact on downstream production arrangements.”

An even more sensitive issue with global warming. “With increasingly severe droughts, Lake Geneva is becoming a strategic reservoirdevelops Christian Bréthault. The regulation of Lake Geneva therefore takes on new importance and also requires re-discussing operating methods.”

France is therefore demanding an agreement to improve the control of the flow of the Rhône. Negotiations began in 2015 between France and Switzerland on this issue. An agreement is about to be finalized for better Franco-Swiss coordination.