GENEVA — At the western edge of Lake Geneva, where the mighty Rhône river squeezes through a narrow dam, a blunder of French diplomacy is carved into stone for all to see.
The inscription, mounted on the walls of an old industrial building, commemorates the 1884 accord between three Swiss cantons that have regulated the water levels of this vast Alpine lake ever since. It does not mention France — even though some 40 percent of the lake is French territory.
“France, for some reason, wasn’t part of the contract,” said Jérôme Barras as he unlocked a gate below the epigraph to inspect a hydropower plant under the dam he has managed for more than a decade.
When the agreement was renewed and a new dam was built a century later, Paris still wasn’t interested.
The French government now regrets that.
The inconspicuous appearance of the barrier, known as the Seujet Dam, belies its strategic importance to feeding and powering France. Barras calls it Lake Geneva’s robinet, or faucet, allowing Switzerland to turn the flow of the Rhône up — or, more notably, down.
And France has suddenly realized it can’t control that tap as it battles water shortages, destructive droughts and baking heat.
“Considering since when we’ve known about climate change and its possible impacts, it was a rather late realization,” said Christian Bréthaut, an associate professor in water governance at the University of Geneva.
Thus far, it hasn’t been a huge problem: The Swiss authorities have generally obliged French requests for more water. But Barras, the dam’s keeper, was blunt: “We have no obligation to react to these demands.”
It’s a perfect recipe for the mounting tensions Brussels has warned could spark water conflicts across Europe.
Last summer, as rivers ran dry across France, Paris convinced Bern and the cantons to start talks over how to jointly manage the life-giving water. Yet Switzerland is reluctant to allow Paris any influence over how much water leaves Lake Geneva. The French should just trust the Swiss to do the right thing, said Antonio Hodgers, president of Geneva’s cantonal government.
“What we say in Switzerland is: Listen, tell us when this has been a problem,” he told POLITICO in an interview in his stately offices overlooking the city. “When did Switzerland fail to respond when France needed it?”
The French aren’t convinced. “We are very lucky to have this water of very good quality,” said Anne Grosperrin, who oversees water resources for the 1.5 million people in and around the French city of Lyon, just downstream from Geneva. “But at the same time, we’re very vulnerable.”
But it’s not just about keeping the city’s taps from running dry. A journey down the Rhône, from its alpine source to Lake Geneva, Lyon and beyond, shows how many lives and livelihoods depend on — and, in times of drought, compete for — the river’s water.
From the Swiss Alps to Lake Geneva
The trouble starts at the top — in the Swiss Alps, where the Rhône gushes from an ancient glacier and spills down the mountain valleys into Lake Geneva.
Thanks to its glaciers, Switzerland acts as the water reservoir of Western Europe, holding 6 percent of the entire Continent’s freshwater reserves. But Alpine ice is melting at an alarming pace.
Switzerland’s glaciers have lost 10 percent of their volume in the last two years alone. And there are signs that the country has already passed “peak water,” meaning glacial meltwater may soon decline, said Daniel Farinotti, a glaciologist at ETH Zurich.
By the century’s end, Farinotti expects to lose 60 to 80 percent of Switzerland’s glaciers. And the Rhône Glacier, which feeds the river, is likely to fare even worse, effectively disappearing entirely by then, according to an ETH study.
That doesn’t mean the Rhône river disappears. Snow and rain in the Alps will continue running down the mountainsides once the glaciers are gone, feeding the river. But snowfall is diminishing and precipitation is much less reliable than glacial ice, which melts — like clockwork — in the warmer months when water is needed most.
Demand for that water is intense. The river supplies 2.5 million people with tap water, moves goods from Lyon to the Mediterranean, cools nuclear reactors, produces a quarter of France’s hydroelectricity and sustains stretches of farmland roughly the size of Belgium.
In short, the Rhône “is essential for the economy of the region, the country and Europe as a whole,” said Thomas San Marco, director for water resources at the Compagnie Nationale du Rhône (CNR), the company managing hydropower, transport and agricultural irrigation along the river for the French state.
But year after year, the river shrinks, at least in the summer. A comprehensive study published last year by the French authorities in the Auvergne-Rhône-Alpes region found that the Rhône’s summer flow had fallen 7 to 13 percent over the past 60 years. And it could drop another 20 percent by 2055, the study estimated.
Still, few Swiss officials, politicians and water managers see reason to act with urgency. Some even argue that a meltwater surge will create a positive side effect for several decades: Boosting hydropower, a climate-friendly energy source.
“There is more and more water flow arriving due to melting glaciers,” said Benjamin Roduit, a center-right lawmaker in the Swiss National Council representing Valais, one of the three cantons governing Lake Geneva.
Roduit, who coincidentally also runs a pro-hydropower lobby outfit, Swiss Small Hydro, argues that harnessing excess water is vital to cutting carbon. As for water scarcity, he said, “I can tell you: Right now, it’s not a priority. On the contrary, the difficulty is not wasting this extra water.”
France doesn’t feel that way. Droughts there are ravaging communities, and violent clashes have erupted over the construction of reservoirs for farmers.
“Tensions already exist,” said Grosperrin, the Lyonnaise politician. That’s why Paris wants a say in the Rhône’s future.
Switzerland is listening — to a point.
From Lake Geneva to France’s nuclear plant
At Geneva’s harbor, not far from the Seujet Dam, a giant fountain shoots thousands of liters of lakewater into the air. The Jet d’Eau, the city’s best-known landmark, almost seems designed to show off its water abundance.
“In Geneva, we are privileged. All the water comes to us,” said Hodgers, the cantonal president. That’s why he feels a responsibility toward the French downstream: “This water is not ours. Water passes, it belongs to everyone.”
But allowing France influence over exactly how much water leaves Lake Geneva is a red line for him and other cantons involved in the negotiations.
“We don’t want to commit ourselves to [certain] volumes of water, because if all of a sudden there’s very little water, we don’t want to have to be obliged to give a lot to France while we don’t have enough for our population,” Hodgers said.
Then there’s the issue of how that water gets used. Switzerland, which has decided to phase out nuclear power, is miffed about guaranteeing water supply so France can cool its expanding nuclear fleet.
The Rhône’s waters are vital to the Bugey nuclear plant, which sits just across the Swiss border — much to the dismay of Hodgers, a Green Party politician fiercely opposed to atomic power.
Many suspect that Bugey, which supplies 40 percent of the Auvergne-Rhône-Alpes region’s electricity, is driving the French government’s sudden interest in the Rhône. Officials are planning to add two more reactors to the site.
“That’s not helping,” Hodgers said.
The Bugey plant is also the main reason France must ask the Swiss to let more water through the Seujet Dam. While most of the water is released back into the river, the reactors need a constant, cool flow — and climate change isn’t only making the Rhône’s water scarcer, but also warmer.
France’s requests are “clearly” becoming more frequent, said Barras, director of electricity production for Geneva Industrial Services (SIG), which manages power, water and energy for the area. The SIG can accommodate such requests, as long as the lake level remains within the limits agreed between the three Swiss cantons.
“That happens always in the summer now,” Barras said. “Because the hydrological situation is changing.”
From France’s power plant to Lyon
In France, this changing situation is dangerous. Water is disappearing, severe droughts are proliferating. People’s jobs — and their health — are under threat.
Facing pressure, French President Emmanuel Macron last year pitched a plan to conserve more of the precious resource, including a pledge to reduce water use by 10 percent by 2030. But there are no binding targets or measures for specific sectors, leaving plenty of room for interpretation.
For French companies managing the Rhône in France, better storage is the goal. But given the Rhône is already highly managed — 19 dams regulate river levels and help store water — these firms don’t see a need for drastic change.
Nicolas Kraak, who runs the administrative body managing agricultural irrigation along the Rhône, shows off a new pump station just northeast of Lyon that he says will relieve pressure on local underground water resources by pulling water from the Rhône River instead. And, Kraak insists, irrigation operators can afford to pull more water from the river.
“It’s clear that water is available. In fact, agriculture is currently only using 35 percent of the river reserves allocated to it,” he said. “Personally, I don’t think there will be any problem on the Rhône.”
In Lyon, Grosperrin shakes her head at the logic. “When the irrigators say it’s well managed, everything is fine — I don’t share this point of view,” she said.
Greater Lyon, which draws 98 percent of its tap water from the Rhône aquifer — the underground water — plans to slash 15 percent of its water use by 2035.
Grosperrin says the city’s consumption is already falling, but she worries about water quality: The Rhône has warmed in recent decades, both due to climate change and because the nuclear plants discharge warmer water, which raises the risk of pollution.
France and the European Union have to ensure farming and industry also use less water, she warned. “We’d really be kidding ourselves if we said we could continue to extract resources like this.”
Despite their disagreements, everyone in France agrees on one thing: There needs to be a formal water-sharing agreement with Switzerland, ideally guaranteeing a certain volume of flow through the Seujet Dam.
The pumps Kraak was touting sometimes stop working when Geneva decides to retain more water, the French irrigation manager said. And outside of a United Nations water convention, Switzerland’s water isn’t subject to many international obligations.
“We have no control over Switzerland because they’re not in the European Union,” Kraak warned. “They do as they please.”
From Lyon to the rest of Europe
France isn’t the only exasperated Swiss neighbor.
For the past few years, Switzerland and Italy have argued about water levels in the Lago Maggiore, which straddles their border. In 2022, drought-stricken Italian provinces asked the Swiss to release more water. And longer term, Italy wants to raise the lake’s water level so it can act as a larger reservoir, something the Swiss say would raise the flood risk.
Asked if Switzerland is concerned about these growing water tensions, Felix Wertli, Bern’s lead negotiator in the talks with France, said: “Climate change knows no borders and makes it necessary to find common solutions. We are confident that the agreement will help the two countries strengthen cooperation.”
Wertli did not elaborate on the state of the talks or details but said he expects to wrap up the negotiations by the year’s end.
In a sign that Paris sees the Rhône’s flow as a matter of national security, the French foreign affairs ministry handles the negotiations, while in Switzerland it’s the federal environment office. Water governance was also reportedly high on the agenda during Macron’s November visit to Bern. (The French foreign ministry did not respond to multiple requests for interviews.)
Still, in Switzerland, where water scarcity won’t be a major problem until the latter half of this century, many take a more relaxed approach.
“France looks at 2050. Switzerland is making studies for 2100,” said Cyrille Vallet, who straddles the Franco-Swiss academic border, studying management of the Rhône at the universities of Geneva and Lyon.
Back at the Seujet Dam, Jérôme Barras similarly isn’t too worried about the immediate future.
“Generally, for the next three decades, we do not expect less hydropower production or less water,” he said.
But what about after that?
Barras shakes his head, pointing out that his company’s contract with the canton only runs until the middle of the century.
“Me, I don’t think about that. It’s the next generation — the next two or three generations of workers and managers,” Barras said. “They would have to see what happens after.”
Zia Weise also reported from Lyon, France.