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Aquifers Can Come Back. Here's How.

When Scott Jasechko at the University of California, Santa Barbara, set out to study whether depleted aquifers could recover, he wasn't sure what he'd find.

The conventional wisdom in water management tends toward pessimism—once an underground reservoir starts draining faster than rain can refill it, the math rarely improves on its own.

But in a paper published in Science, Jasechko assembled something unexpected: evidence that groundwater recovery is not only possible, but has actually happened, in 67 documented cases around the world.

Diverse Success Stories

The cases span continents and circumstances. They include megaprojects like China's South-to-North Water Diversion Project, which redirects river water hundreds of miles to water-starved northern provinces, and far smaller interventions, like Osaka simply beginning to tap the river running through its own streets.

Some locations reversed decline within a few years; others took decades. Bangkok started taxing groundwater use in the late 1970s but didn't see water levels respond until fees were raised high enough to actually change behavior—more than 20 years later.

Three Strategies That Work

Jasechko identified three broad strategies that appeared again and again across the successful cases:

Strategy 1: Importing Water

Present in 81 percent of cases, importing water made the difference. Conservation alone rarely moved the needle; what worked was finding an alternative supply that could substitute for groundwater.

Some places built dams across borders, others laid pipelines from distant rivers, and some just started using surface water they'd previously ignored.

Strategy 2: Reducing Pumping

Roughly half the cases involved fees on groundwater extraction, outright bans on new well drilling, or regulations that changed how companies operated.

Japan shifted away from concentration-based wastewater limits—when your discharge can't exceed a certain pollutant level, the easy workaround is to pump up massive amounts of groundwater to dilute your waste. Once that loophole closed, pumping dropped.

Saudi Arabia banned alfalfa cultivation entirely, a move that reverberated all the way to Arizona, where a Saudi-owned operation had been leasing land to grow the water-intensive crop for export.

Strategy 3: Artificial Recharge

Nearly half the cases studied included deliberately putting water back into the ground. For shallow aquifers, this means spreading water across a wide surface area so it can percolate down through sediment.

For deeper, sealed-off reservoirs, it means pumping water down through wells at rates the formations can accept.

Sometimes this recharge happened accidentally: leaky irrigation systems and aging diversion canals ended up nourishing aquifers nobody was trying to refill.

Side effects of recovery cut both ways. Rising water tables pushed back against saltwater intrusion in coastal areas, and groundwater recovery halted land subsidence in Shanghai, Bangkok, and Houston.

Unintended Consequences

While many side effects proved beneficial, pushing water back into the ground created new problems in some places.

Soils that had been dry for decades swelled as they saturated, shifting the surface upward in ways that occasionally triggered earthquakes in seismically active zones.

In Turkey and Iran, waterlogged farmland evaporated over time, concentrating salts in the soil. Low-lying areas and tunnels flooded in cases where too much water returned too quickly.

The most consistent lesson across all 67 cases is that recovery required mixing approaches. Almost every success story combined at least two of the three main strategies—adding supply, cutting demand, and recharging the aquifer. Single-pronged interventions rarely sufficed.

The study also underscores that patience matters: climate variability means wet years and dry years will mask or amplify results, and turning a declining trend around takes time that politicians and communities rarely want to hear about.

Jasechko's map of all 67 recovery sites is, in its own way, an argument against fatalism. The details in each case differ—the geology, the policy tools, the timeline—but the direction is clear.

Depleted aquifers are not necessarily permanent monuments to overuse. They can fill again.

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Based on: Aquifer Recovery Research; Scott Jasechko; University of California, Santa Barbara, Science Journal.