This story was originally published by Undark and is reproduced here as part of the Climate Desk collaboration.

Just ahead of the Great Recession, in 2005, Carolyn Chism Hardy got the news that the Coors brewery where she worked would close for good the next year. Following a merger with Molson, her higher-ups told her, the Memphis, Tennessee, operation was no longer cost-effective. As the plant manager, Hardy was charged with telling hundreds of employees that they would soon be out of work.

But Hardy had another plan. She would fundraise, buy the brewery herself, and save her co-workers’ jobs. Hardy says company executives were skeptical that someone with her background would be able to raise the money. Hardy grew up poor in Memphis’ Orange Mound neighborhood and she hadn’t yet owned and operated a business. But she came through with the money. “And the rest is history,” she says.

Hardy was confident in the new operation in part because of its access to the Sparta-Memphis aquifer: an underground reservoir that, if drained, would fill Lake Michigan. It exists at the surface in some places and reaches over 1,000 feet below ground in others. Owing to the water’s purity, there’s no need for the extensive and expensive filtration process required elsewhere, says Hardy.

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The Sparta-Memphis aquifer is part of a larger geological formation of multiple intermingling aquifers called the Mississippi Embayment, a thick layer cake of sunken deposits. Some deposits are relatively dense, including silt and clay, which protect and confine more porous and permeable sand and gravel layers, all of which are made up of ancient river, delta, and coastal deposits covered and carved out by the rising and falling of seas in between ice ages. The aquifer system, including the Sparta-Memphis aquifer, is now saturated with freshwater. The water resting here first fell to the Earth as rain between two and three thousand years ago, then trickled into the ground through what are known as “recharge zones,” areas that are unconfined, or exposed at the Earth’s surface, and where sandy soils and other sediments allow for percolation into deeper aquifers. (Rain that falls to the ground on much of the Earth’s crust collects in more shallow alluvial aquifers that are both “younger” and tend to contain more pollutants). Given the slower-than-glacial pace at which water has percolated through each layer, when water from the Sparta-Memphis aquifer flows from a well to a faucet today, it commonly hasn’t seen the light of day for thousands of years.

This process, which amounts to top-notch natural filtration, has meant low overhead costs for any number of water-intensive businesses in Memphis, where wells pump an estimated 180 million to 200 million gallons per day. But Memphis is far from the only party that pulls from the aquifer, which underlies eight states in total. According to mapping by the U.S. Geological Survey, neighboring Arkansas and Mississippi pump 170 million gallons per day and 97 million gallons per day, respectively. Whiskey distillers, pharmaceutical companies, and national bottled water companies are among the many businesses that rely on the source on either side of state lines.

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But the heavy pumping is catching up with the region. Across the aquifer system’s eight states, hydrogeologists have identified 20 “cones of depression,” points of significant drawdown of the groundwater surface that appear in hydrogeological simulations like fingerprints pressed selectively, but deeply, into bread dough. One of these cones has declined about 100 feet below preindustrial levels under Memphis, just barely edging into Arkansas and Mississippi. It’s been the subject of numerous lawsuits over the past 15 years. In a case currently before the U.S. Supreme Court — with a final ruling that could come next term — the state of Mississippi claims that Memphis has “forcibly siphoned,” or effectively stolen, its water, which Mississippi frames as its “sovereign territory.”

That’s a new way of thinking about water. For almost two centuries, with few exceptions, the U.S. legal system has protected water as “res communes,” a public thing owned by no person or government body and subject to use by all under common law. It’s a special status given to few other things, like air, sunlight, and outer space. While Tennessee and the other defendants have tried to get the suit thrown out, Mississippi has pressed on, seeking a multi-million-dollar payout and a ruling that would push the city of Memphis to draw from the Mississippi River and from wells further north or east — away from Mississippi state lines.

Previous cases have resolved surface water disputes between states, but this is the first Supreme Court case to resolve a dispute over groundwater that crosses state lines. And while some experts say the case should have been closed years ago by lower courts and with trained water mediators, the pending Supreme Court decision could redefine how states, municipalities, industries, and individuals work together to manage water — groundwater in particular — as rivers and lakes run dry, forcing communities across the world to cope with freshwater scarcity amid the climate crisis.






Aquifer visual

A NATURAL, AND HIGHLY PRIZED, FILTRATION SYSTEM: The Sparta-Memphis aquifer is one of several aquifers layered in a larger geological feature called the Mississippi Embayment. For tens of millions of years, water has entered the Embayment, seeping through recharge zones on the Earth’s surface. That water percolates downward and laterally, as indicated by blue arrows, through layers of sand and gravel sandwiched between less permeable silt and clay layers, which do not allow water to move through them easily. The Embayment is visible above ground as a low elevation region between the Ozark and Ouachita mountains and the Tennessee River. Deposits of wind-blown dust (known as “loess deposits”) form bluffs along the Mississippi River. Hence Memphis is sometimes called the “Bluff City.” Additionally, deposits made of clay, silt, sand, and gravel (known collectively as “alluvial deposits”) fill the valleys of the Mississippi River and its major tributaries. Sources: John Van Brahana / University of Arkansas; Daniel Larsen and Brian Waldron / University of Memphis. Visual: Mike Rogalski / Eyewash for Undark

In the United States, water’s protected status dates back to a slew of litigation in the early 1800s, when courts concluded that bestowing water ownership rights to a state could be catastrophic. “It would be a grievance which never could be long borne by a free people,” an 1821 New Jersey Supreme Court decision found. U.S. Supreme Court rulings throughout the following decades affirmed as much, including an 1892 Supreme Court decision over submerged lands and tidewater in the Chicago harbor, in which the court found that states do hold the title to said land but that it is fundamentally “different in character” than a land title that could be bought or sold, “held in trust for the people.”

Modern water law varies across states. In Texas, for instance, landowners have the right to pump and capture groundwater molecules beneath their property. But that’s significantly different from allowing an individual, a corporation, or a government to own the water itself, says Wayne State University water law professor Noah Hall. If the latter scenario were the norm, he explains, it would allow for speculators to effectively “sit” on their liquid property until it becomes more profitable to sell it — when water becomes even more scarce. Severe water scarcity is expected to impact up to 3.2 billion people worldwide by 2050.

On account of this legal precedent, Hall says, Mississippi v. Tennessee has been thrown out multiple times since Mississippi Attorney General Jim Hood originally filed the suit against the City of Memphis and its utility company in 2005, alleging the cone of depression under western Tennessee had created a gradient causing water to flow toward the city that would otherwise sit under Mississippi. In addition to seeking limits on Memphis’ withdrawals from the aquifer, Mississippi sought no less than $615 million in damages. The original case was dismissed in District Court, and again by the Fifth Circuit Court of Appeals, after which the Supreme Court denied the state’s attempt to overturn the ruling and file a new suit.

Then, in 2014, Mississippi added the State of Tennessee to its list of defendants and sued again. This time, the Supreme Court took the suit. Much of Mississippi’s efforts in arguing its case, and claiming ownership of the water beneath it, has centered on questioning, or attempting to refashion established scientific concepts, like whether groundwater is fundamentally different from surface water.

“I don’t know if anybody skis on the Mississippi River,” lead counsel for Mississippi, Michael Ellingburg remarked during a five day evidentiary hearing in May 2019, “but if you dropped [a water ski] in the channel on the Mississippi River, a day later you’d find [it] about 50 miles away.” The comment was the beginning of an attempt to argue that the relative speed at which water molecules flow through surface water should mean that slow-drifting groundwater be treated distinctly by the law, as “sovereign territory,” rather than as a common resource. Mississippi has also attempted to draw this distinction by presenting a “two aquifer” theory, suggesting that what is colloquially known as the Sparta Sands aquifer in Mississippi and Arkansas is structurally distinct from what Memphians call the Memphis Sands aquifer, when according to the USGS the two aquifers are hydraulically connected and refer to the same underground reservoir.

A river barge pushes its cargo up the Mississippi River as the sun sets in Memphis, Tennessee. Samuel Corum / Anadolu Agency / Getty Images

The case has given voice to nebulous discussions, rather than directly determining who caused damage and exactly how to remedy it, Hall says. This, he suggests, could help explain the relative lack of attention given to the landmark case — even among environmentalists and local business owners like Hardy, whose livelihoods center on aquifer water.

After studying the case extensively, in 2019, Hall co-authored an amicus brief urging Special Master Eugene Siler, Jr. — a Sixth Circuit Court of Appeals judge who the Supreme Court appointed to hear evidence on behalf of the Court and issue a recommended ruling — to use the decision as an opportunity to “craft a rule that sensibly balances the many competing needs for groundwater.” In other words, while the suit wasn’t necessarily brought to address water scarcity, Hall says, since it remains before the Court, the powers that be might as well use the opportunity to guide the region in establishing a process for future disputes over aquifers.

Culturally, particularly in the Eastern United States, groundwater is still very much “out of sight out of mind,” Hall says. The United States still pulls primarily from surface water sources, but since 1950, groundwater withdrawals have more than doubled. Conflict over the unseen water beneath our feet is not so much a futuristic scenario, but one that’s just now heating up.

“Sharing groundwater has been a difficult issue for governments to tackle,” said Todd Votteler, in an email to Undark. A water mediator who heads the firm Collaborative Water Resolution, Votteler helped oversee a decades-long dispute over the Edwards Aquifer in San Antonio. “There are over 400 international agreements concerning shared surface water resources,” he says, like The Great Lakes–St. Lawrence River Basin Water Resources Compact, which is a legally binding agreement between eight states that largely prevents any entity from extracting water for use or sale beyond adjacent counties.

In contrast, only a few agreements exist over shared groundwater, both in the U.S. and internationally, says Votteler. To properly manage a body of water, one must first quantify it — easy enough when dealing with surface water. But estimating how much water is in a given underground source requires highly technical processes like extensive drilling, or artificially inducing seismic vibrations by setting off explosives underground.

Geologist Deborah Carington grew up drinking Sparta-Memphis aquifer water on her family farm in northern Mississippi. Now she lives in San Antonio, where she’s on the board of the Edwards Aquifer Authority, an eight-county water management agency which Votteler describes as unique.

In contrast to the Mississippi v. Tennessee case, legal battles over the Edwards Aquifer in south central Texas, which resulted in the creation of the EAA, were heated. Angry environmentalists, catfish farmers, municipal, and industrial interests filled courtrooms. Part of that, Carington says, was because the Edwards Aquifer is more evident to residents. It’s a karst limestone aquifer, rather than a sand aquifer, with vast caverns, sinkholes, and springs throughout. “Just north of the city, people go caving” she says, “and when the water level drops, they experience the lack of water when we have a drought.”

City skyline of San Antonio.

City skyline of San Antonio. Legal battles over the nearby Edwards Aquifer were heated, and resulted in the creation of the Edwards Aquifer Authority. Loop Images / Universal Images Group via Getty Images

The Sparta-Memphis aquifer offers no such majestic glimpse underground. “Here, we’ve got this trickle process that goes on for millennia,” founder of the Memphis-area group Protect Our Aquifer, Ward Archer says. And that makes conservation a challenging task. Taking a sip of tap water, or aquifer-brewed beer, for example, tends to be the closest to the aquifer local residents can get.

Carington got involved with Protect Our Aquifer around 2017, when she learned that the Tennessee Valley Authority had applied a year earlier to drill a set of wells that would use Sparta-Memphis aquifer water to cool a natural gas-burning power plant. “I was so surprised that industries, private well owners, do not pay for their water,” she recalls, having grown accustomed to life in San Antonio, where a meticulously-designed price structure based on aquifer water volume charges agricultural, industrial, and municipal users different rates. The money is then pooled to fund the EAA, which includes undertaking studies that track water levels, recharge rates, and potential contaminants. “I saw the need right away for a better way,” says Carington. If the water is free, then there’s no incentive for conservation.

Over the past few years, Carington, Archer, and others have been pushing for more stringent rules around private wells. Among other things, they have worked with Shelby County leaders in charge of groundwater management to activate a conservation fee for private well pumping in and around Memphis. “We’re starting at this local level, in Shelby County, but it really in the long term is going to need to be a regional solution,” Carington says.

The Court’s upcoming decision in Mississippi v. Tennessee presents a possibility, however slim, of a sort of expedited job. In theory, the Special Master could instruct Mississippi and Tennessee to pull in other states with Sparta-Memphis aquifer water below, to work on a collaborative solution, Archer describes. “That’s the kind of power that you need to start one of these things,” he says, referring to a groundwater management group like the EAA, which was formed in response to legislation Texas lawmakers passed in 1993, under threat that otherwise, management would be handed to the federal government. The EAA, which is a political subdivision of the state, posts daily data, like water levels at multiple points within the aquifer, and an estimated annual recharge rate. If levels get low, a new set of conservation measures kick in. Parts of that model have since prompted similar programs elsewhere, says Votteler, such as in California’s Sustainable Groundwater Management Act, which state legislators passed in 2014, after three consecutive years of severe drought.

A final ruling in Mississippi v. Tennessee that orders parties to involve all eight states in agreeing on a system for managing its groundwater, such as through the creation of a regional authority, would provide a model for solving — or avoiding — conflicts over groundwater that crosses state borders. And it would be particularly forward-thinking given that the cone of depression at issue under Memphis is actually one of the least concerning in the Mississippi Embayment. Cones of depression under Louisiana and Arkansas state lines, for instance, have declined by up to four times as much as those under Memphis, since predevelopment.

Short of a Supreme Court mandate to do so, a future interstate groundwater authority might take decades to form. Carington thinks businesses owe it to the communities they’re a part of to begin to collaborate on managing the region’s most precious resource. All that value, that economic incentive the aquifer provides, can be lost if parties pump blindly without a system for monitoring and managing the massive body of water, she says. “We have the quantity in Memphis, but we have to protect it.”

While a ruling in Mississippi v. Tennessee could kick-start an interstate groundwater conservation effort, Hall worries about an alternative outcome. If the court rules that Mississippi does “own” groundwater within state lines and that damages are due, other states would likely go down the same road, Hall says, seeking damages to bolster state coffers. (Attorneys for Tennessee declined to comment on the pending litigation; attorneys for Mississippi did not respond to repeated requests for comment.)

Such a ruling would open the door for states to sell groundwater, or future groundwater rights, to help stave off school budget cuts or to pay for fixing potholes — to “sell off the future to pay for the present,” Hall explains. That new paradigm would effectively require citizens to buy back water later, at a higher price. “People would be facing the same sort of debt or bankruptcy situation over paying for their water as they have in paying for their homes or paying for their education or paying for their medical care,” Hall says, aghast.

Either way, the case signals the beginning of a new phase, Votteler says, of conflicts over water shifting from the arid western United States to the East. Other interstate water cases await rulings this year as well, such as a dispute between Florida and Georgia over water that flows through the Apalachicola-Chattahoochee-Flint River Basin. But Mississippi v. Tennessee is the only such case that deals with groundwater extraction.

In addition to serving as a model for states to work together to manage transboundary aquifer water across state lines, the Sparta-Memphis resolution could also pave the way for collaborating on managing aquifers that cross national borders, like a series of at least 36 intertwined aquifers below the U.S.- Mexico border, which the two countries have only just begun to grapple with.

In the meantime, Memphians like Hardy continue to embrace their region’s water, which has helped sustain the local economy and culture. As one craft brewing establishment explains on its website, “Breweries in Memphis are blessed with access to the best water on Earth. That’s why every brewery in Memphis uses it.” But unlike lakes and rivers, or even karst aquifers like the Edwards, which refill after a big storm, water in sand aquifers can take centuries, even millennia, to replenish. That means locals and governments must collaborate, says Votteler, and the sooner the better. “Once you take all that water out, you’re done.”