French People Are Fighting Over Giant Pools of Water

The underground reserves that fill mega-basins are not an infinite resource.

These are not your average reservoirs.

The plastic-lined cavities span, on average, 20 acres—more than 15 American football fields. Nicknamed "mega-basins," they resemble enormous swimming pools scooped into farmland; about 100 basin projects are in the works across France. In wetter winter months, the basins are pumped full of groundwater; during punishing droughts and heat waves, those waters are meant to provide "life insurance" for farmers, who are among the region's heaviest water users.

In 2022, France faced its worst drought on record; 2023 stands to be worse still. In 2020, anticipating future dry spells, federal environmental and agricultural agencies proposed prioritizing and subsidizing basins as "the most satisfactory way of securing water resources."

But critics say that this so-called climate-change adaptation is, in reality, a maladaptation—a lesson in how not to prepare for water scarcity. Already, almost two-thirds of the world's population experiences a water shortage for at least one month each year, and "basins are absolutely not the solution," Christian Amblard, a hydrobiologist and an honorary director at France's National Center for Scientific Research, told me.

Humans have, for millennia, smoothed out seasonal water availability by damming rivers or lakes to create artificial reservoirs. Jordan's Jawa Dam, the world's oldest, is 5,000 years old. But the first mega-basins in France were built only a few decades ago and, unlike traditional dams, draw some of their reserves from underground. Once on the surface, this water becomes vulnerable to evaporation (even more so as the planet warms) and to pathogens including bacteria and toxic algae.

France is not the only country collecting groundwater to combat major droughts. Others have done the same, with devastating effects on local people and ecosystems. In Petorca, Chile, about 30 groundwater-rights bearers control 60 percent of the region's total streamflow; most residents depend on a few daily hours of access to water-tank trucks for their needs. In India, groundwater is a primary source for drinking water; overexploitation has led to declining groundwater levels across the country and could slash some winter agricultural yields by up to two-thirds, experts warn. Iran has increased its groundwater withdrawal by 200,000 percent over the past 50-plus years and now faces a potential state of "water bankruptcy."

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Climate change will leave many regions alternating between harsh multiyear droughts and sudden, extreme flooding—all as the water frozen in Earth's poles, glaciers, and permafrost melts away. Groundwater might seem to be a limitless resource of moisture in the unpredictable and imbalanced future. But it's not, and scientists say that the freshwater lying beneath our feet should be managed like any other nonrenewable resource.

"They’re thinking very short-term," Amblard said of mega-basin proponents. "Water needs to stay in the ground."

Surface water is all the water we can observe: ponds, streams, rivers, lakes, seas, and oceans. It coats almost three-quarters of the planet. When we imagine water, we usually envision surface water.

Our stores of groundwater, on the other hand, are invisible and vast. Most of this water is stored in the gaps between rocks, sediment, and sand—think of it like the moisture in a sopping wet sponge. Some groundwater is relatively young, but some represents the remains of rain that fell thousands of years ago. Overall, groundwater accounts for 98 percent of Earth's unfrozen freshwater. It provides one-third of global drinking water and nearly half of the planet's agricultural irrigation.

Water is constantly cycling between below-ground stores and the world above. When rain falls or snow melts, some replenishes surface waters, some evaporates, and some filters down into underground aquifers. Inversely, aquifers recharge surface waters like lakes and wetlands, and pop up to form mountain springs or oases in arid lands.

Despite our utter dependence on groundwater, we know relatively little about it. Even within the hydrological community and at global water summits, "groundwater is kind of sidelined," Karen Villholth, a groundwater expert and the director of Water Cycle Innovation, in South Africa, told me. It's technically more difficult to measure than visible water, more complex in its fluid dynamics, and historically under- or unregulated. It "is often poorly understood, and consequently undervalued, mismanaged and even abused," UNESCO declared in 2022. "It's not so easy to grapple with," Villholth said. "It's simply easier to avoid."

Take a crucial U.S. groundwater case, 1861's Frazier v. Brown. The dispute involved two feuding neighbors and "a certain hole, wickedly and maliciously dug, for the purpose of destroying" a water spring that had, "from time immemorial, ran and oozed, out of the ground." Frazier v. Brown questioned the rights of a landowner to subterranean water on the property. Ohio's Supreme Court ultimately argued against any such right, on the premise that groundwater was too mysterious to regulate, "so secret, occult and concealed" were its origins and movement. (The case has since been overturned.)

Today, groundwater is still a mystery, says Elisabeth Lictevout, a hydrogeologist and the director of the International Groundwater Resources Assessment Centre in the Netherlands. Scientists and state officials often don't have a complete grasp of groundwater's location, geology, depth, volume, and quality. They’re rarely certain of how quickly it can be replenished, or exactly how much is being pumped away in legal and illegal operations. "Today we are clearly not capable of doing a worldwide groundwater survey," Lictevout told me. Without more precise data, we lack useful models that could better guide its responsible management. "It's a big problem," she said. "It's revolting, even."

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Water experts are certain, however, that humans are relying on groundwater more than ever. UNESCO reports that groundwater use is at an all-time high, with a global sixfold increase over the past 70 years. Across the planet, groundwater in arid and semi-arid regions—including in the U.S. High Plains and Central Valley aquifers, the North China Plain, Australia's Canning Basin, the Northwest Sahara Aquifer System, South America's Guarani Aquifer, and several aquifers beneath northwestern India and the Middle East—is experiencing rapid depletion. In 2013, the U.S. Geological Survey found that the country had tripled the previous century's groundwater-withdrawal rate by 2008. Many aquifers—which, because they are subterranean, cannot easily be cleaned—are also being contaminated by toxic chemicals, pesticides and fertilizers, industrial discharge, waste disposal, and pumping-related pollutants.

Because these waters are hidden and can seem "infinite," Lictevout said, few people "see the consequences of our actions." She and other hydrology experts often turn to a fiscal analogy: All of the planet's freshwater represents a bank account. Rainfall and snowmelt are the income. Evaporation and water pumping are the expenditures. Rivers, lakes, and reservoirs are the checking account. Groundwater is the savings or retirement fund—which we are tapping into.

"We have to be careful about dipping into our savings," says Jay Famiglietti, an Arizona State University hydrologist and the executive director emeritus of the University of Saskatchewan's Global Institute for Water Security.

As they face down hotter and drier growing seasons, some French farmers say the water backup of basins is crucial to food security. (Agriculture, according to the federal government, accounts for two-thirds of France's total water consumption.)

"If we don't continue with this project, there are farms that won't survive," Francois Petorin, an administrator of the 200-plus-farm Water Co-op 79, in Western France, has said. "We have no other choice."

Under a deal with local water authorities, farmers can access set volumes from the basins in exchange for reducing pesticide use, planting fields with hedges, and increasing biodiversity. Proponents of the mega-basins also argue that they would be careful to pump only when groundwater levels are above certain thresholds and would draw from shallow aquifers that could be quickly recharged by precipitation.

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Experts don't disagree that groundwater must be a part of adapting to climate change. But many argue that overdependence on and overexploitation of a shrinking natural resource cannot be the solution to a problem created by the overdependence on and overexploitation of nonrenewable natural resources.

Instead, experts told me that regulated groundwater tapping could be paired with other adaptations—many of which involve reducing water use and consumption. Farmers could swap out water-intensive crops such as corn (which is grown on 60 percent of France's irrigated lands, much of it for livestock) in favor of drought-resistant species adapted to local climates. They could employ more efficient irrigation technologies and plow less, which would make for healthier, more permeable soil, which could retain more water and filter it down more effectively to aquifers. Reducing meat consumption and cutting down on food waste would also shrink water use. Instead of drawing groundwater up for dry seasons, we could inject and help infuse water into depleted aquifers for storage.

"It is a common resource, at the end of the day," Villholth said. "It's an issue of equity. It's almost a democratic question."

That's certainly how France's mega-basin opponents see it. They have staged numerous protests and acts of civil disobedience, including planting hedges on land earmarked for basins and excavating crucial pumps and pipes. In March, thousands of activists (30,000 according to organizers, 6,000 according to state officials) faced off against 3,000 militarized police over the construction of a new mega-basin in Sainte-Soline, in western France, that would supply 12 farms. Organizers say 200-plus people were injured by tear-gas grenades and rubber-ball launchers. A few weeks later, a French court approved the construction of 16 heavily subsidized mega-reservoirs in western France, including the one at Sainte-Soline.

This is one advantage of mega-basins: They make the invisible hyper-visible. "It puts the matter in front of everybody," Villholth said. Pulled to the surface, groundwater becomes more measurable, as does its use—as do debates over the ethics of its use. But that won't tell us how much is left. If we’re not careful, we’ll discover that only once it's all tapped out.