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Not a Drop to Drink

A hydrologist uses satellite data to show that we are depleting critical water supplies, and fast

The signs that we are depleting our water supply are emerging around the world—in the Middle East, northern India, western Australia, and closer to home in California, which is in the grips of a four-year drought. Municipalities have enacted bans on washing cars and watering lawns, and in January, Governor Jerry Brown declared a state of emergency. Then in March, Jay Famiglietti, A82, E16P, a University of California–Irvine hydrologist currently working with NASA, wrote an op-ed in the Los Angeles Times titled “California has about one year of water stored. Will you ration now?” The story instantly caused a furor; within weeks, Brown enacted mandatory cuts in government water usage for the first time in history.

Backlash came just as quickly from NASA’s Jet Propulsion Laboratory (JPL), which was credited as the source for the bold claim. Famiglietti heads up the JPL’s new Western States Water Mission, an all-hands-on-deck effort he compares to the moon mission. Its goals include helping California address its persistent drought. However, Famiglietti notes that authors don’t write headlines, and that the one that the Times slapped on his opinion piece exaggerated his point, which is that the state only has a year of water stored in its surface reservoirs, not its groundwater reserves. His larger point: immediate action is required to protect the state’s subsurface waters.

He offers no apologies for the confusion, and in fact almost seems to revel in it, disavowing the sensationalism at the same time he subtly stokes it. “I’m thankful for that headline,” he says. “It’s the reason the article got the attention it did. Our state is going through the driest period in the past thousand years.” Indeed, last winter in California was the hottest and driest on record, according to some accounts, and the state got the least amount of snowfall in five hundred years.

What has Famiglietti especially worried is that although groundwater still may be available for Californians to draw on, the supply is not unlimited. Many of the reserves they’re tapping into now date from the end of the last Ice Age fifteen thousand years ago, when gravel, silt, and clay soaked up the meltwater from dying glaciers. Over millennia, such meltwater created vast underground aquifers all over the planet; today, the aquifers are replenished when precipitation trickles into the ground, but in California, there has been far too little of it.

Famiglietti, who has a rare knack for making science immediately accessible to the public, explains that streams and rivers are like cash, while reservoirs are like a bank account, from which we can withdraw funds and to which we can make deposits. Groundwater, however, is like a 401(k) account—long-term savings that we dip into at our peril—and Californians have been dipping into it at an alarming rate. They now take seventy-five percent of their water from that source, compared with a normal rate of thirty-three percent.

“If we focus just on the last drought going back to 2011, California has lost sixteen trillion gallons of water, with a T,” says Famiglietti. “Two-thirds of that is from groundwater.” It’s a loss the state can ill afford, given its enormous thirst. In 2010, for instance, Californians consumed some thirty- eight billion gallons of water a day from all their stores combined, according to the U.S. Geological Survey. That’s equivalent to draining the state’s largest reservoir, Lake Shasta, every forty days. “We are using way more water than we get from rain and snow melt,” Famiglietti warns. “We are taking money out of the bank—we need to recognize that and control the rate at which we take out that money.”

In a study published this July in the journal Water Resources Research, Famiglietti and several colleagues offered hard evidence of just how fast our groundwater is being depleted. Intriguingly, that evidence came from space. Famiglietti is part of a JPL team monitoring water with two satellites, each the size of a “squashed minivan,” that orbit the earth around the poles about two hundred kilometers apart. The project, called the Gravity Recovery and Climate Experiment (GRACE) mission, “works like a scale in the sky,” he says, and covers the entire surface of the planet in detail roughly once a month.

GRACE takes advantage of the fact that water has an extraordinarily high density compared with most other substances on earth, as anyone who has ever lifted a heavy jug of bottled water at the supermarket might suspect. Because of that, areas with a lot of water—such as Texas, which recently experienced record floods—exert a stronger gravitational force. “Those regions actually gain a lot of weight from water mass,” he says. “They pull the satellites close to the earth a little bit, just like when you step on a scale.” By contrast, the satellites fly somewhat higher when they reach a drought-stricken area like California, because the gravitational pull lessens slightly.

Over the twelve years GRACE has been orbiting the earth, it has revealed that of the world’s thirty-seven largest aquifers, thirteen are being depleted with little or no replenishment. In North America, those aquifers include the California Central Valley Aquifer System, the Texas and Oklahoma section of the Ogallala Aquifer, and the Atlantic and Gulf Coastal Plains Aquifer, which underlies the coast from North Carolina to northern Mexico. Other highly stressed aquifers run in a band along the arid and semi-arid regions of the world, including the Caucasus, the Middle East, India, and China.

Unfortunately, though, it’s hard to put any of the data into perspective, because while GRACE can indicate with remarkable accuracy how much water is being depleted, it can’t tell how much water is actually there. It’s as if a scale could tell you that you lost five pounds in a month but couldn’t tell you how much you currently weigh. Or, to revisit the banking analogy, it’s as if you knew your expenses but not your bank balance.

A second paper Famiglietti and his colleagues published in the same issue of Water Resources Research laid out this dilemma for the first time in the scientific literature, and urged the scientific community to search for ways to solve it. The necessary technology—ranging from old fashioned drilling to modern isotopic studies—exists, says Famiglietti, and is regularly used. It measures the size of oil deposits, for example. “The problem is water is too inexpensive, so we have never explored our aquifers as though they were oil reservoirs,” he points out. “But that is exactly what needs to be done. We can’t estimate the gap between the supply side and the demand side without knowing how much is there. That’s pretty crazy—and we need to get on that.”

An animal lover and camping enthusiast since his childhood in Rhode Island, Famiglietti originally chose Tufts intending to become a veterinarian. That quickly changed. “I found myself unprepared for the rigor of pre-med, pre-vet study,” he says with a chuckle. After wandering into Jim Hume’s geology class, “I just fell in love.” He excelled in geology’s unique style of problem solving. “You’d be given a mystery, but it was a natural mystery, an earth mystery,” he says. “The combination of being confronted with an interesting puzzle and then being able to go outside and see the clues firsthand was very appealing to me.”

By his graduation in 1982, the environmental movement was in full swing, with an emphasis on clean air and water. Famiglietti decided to study hydrology, earning his master’s at the University of Arizona and his Ph.D. at Princeton before becoming a professor at the University of Texas at Austin in 1994.

That’s where he was introduced to GRACE, which an enthusiastic group of young scientists intended to use primarily to measure how climate change affects the rate of polar ice melt and sea level rise. He was skeptical at first. “Like most people I didn’t really understand that groundwater changes would be large enough to affect gravity fields,” he admits. But as he began to analyze the technique, he became convinced of its value—especially for assessing aquifer depletion. When he left for UC–Irvine in 2001, he remained active in the project, tracking the data after GRACE’s launch the following year.

Living in California, Famiglietti has been able to witness the devastation firsthand, which has fueled his sense of urgency. Ominously, too, the patterns GRACE has uncovered are consistent with global models of climate change, which predict that the wetter latitudes, including northern latitudes and the tropics, will get wetter over time, while the dry areas in the middle will get drier. And those dry middle areas, such as California, are also the ones where the climate is temperate, ideal for growing crops—providing water is available.

Famiglietti anticipates that California’s troubles will get worse before they get better, at least in the immediate future. “We can expect to see higher water prices, higher food prices, and more battles over water availability and water rights,” he says. “We’re not going to be refilling these aquifers.” In fact, as long as the pace of climate change goes unchecked, the aquifers will only dry out more.

California has its work cut out for it. The first order of business is to recognize that current rates of water consumption are unsustainable. “It’s like we are addicted to water,” Famiglietti says. “We need to admit that we are addicted and are using more than we have available to us on a renewable basis.” The next task will be to figure out how to use less.

Conservation is especially crucial in agriculture, which consumes eighty percent of the water in the Golden State. Encouragingly, efficient techniques such as drip irrigation have become even more so with the use of buried tubes to minimize evaporation. “It’s like placing water precisely on the roots of plants,” Famiglietti says. Still, all the conservation in the world can’t change the mix of the state’s crops, which are ill suited to an arid environment. Particularly egregious are those like rice, which depend upon wasteful flood irrigation. Orchard crops like fruit and nut trees and grapes are just as problematic, because they require water year-round to survive.

To make matters worse, California’s orchard crops include such moneymakers as pistachios, almonds, and walnuts, none of which farmers show any sign of giving up. “In the southern Central Valley they are everywhere,” Famiglietti says. “Not to be cliché, but as far as the eye can see, you’d be hard pressed to find crops that aren’t trees. And the babies are lined up on the side of the field ready to be planted.”

More progress has been made in urban and suburban areas, where Californians are implementing a number of innovative water conservation techniques. They include sewage recycling, which takes water straight from the sewage treatment plant and, instead of flushing it into the ocean as usual, reroutes it to a water treatment plant next door. “People have to get over the ‘yuck factor,’ ” says Famiglietti. In large part, they have. In Orange County alone, sewage recycling has provided twenty-five percent of the water replenishing the supply. “It’s been a godsend,” he says. “It’s really helped us manage this drought.”

Another promising technology is desalination—taking the ready supply of water from the ocean and making it safe to drink. San Diego broke ground a year ago on a $1 billion desalination plant; when finished it will be the world’s largest, purifying fifty million gallons of seawater a day and providing drinking water for ten percent of the county’s 1.1 million households. Fourteen other such plants are proposed or under construction along the coast.

Desalination is not without its drawbacks, however. The plants, which typically run on coal or natural gas, are very expensive and energy-intensive to run, and emit excessive amounts of greenhouse gases that contribute to climate change. Some small “demonstration” desalination plants in California run on solar energy, but full-size solar desalination plants would be much more expensive to build. Moreover, not even solar desalination plants would be without problems, because the concentrated brine released as a byproduct of desalination is incredibly toxic to plants and wildlife. “It’s an environmental nightmare,” says Famiglietti. “It basically kills anything it comes into contact with.” As of yet, no cheap, effective solution has emerged.

Other options the state is looking at include transporting water from other areas where it is more plentiful. Although that’s doable—water has been brought in from northern California and the Colorado River for decades—it’s also incredibly expensive, and does little more than put a Band-Aid on the problem. But Famiglietti believes all possible solutions must remain on the table if the state is to avert an environmental catastrophe. “There were many things I used to think were crazy that may not be so crazy,” he says. “Everything is worth considering, because even if they don’t work, there may be aspects of the proposals that are still important.”

That open-mindedness is matched by a deep sense of commitment. Whether he’s parsing data from GRACE with his JPL team or penning journal articles and op-eds, Famiglietti will continue to train his attention on the dire situation in California. He is not without optimism. “We can manage our way through,” he insists. But he adds that “first we need to understand and come to grips with the problem.”

Michael Blanding is a Boston-based freelance writer and frequent contributor to Tufts Magazine.

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