A bit of good news: It’s possible to turn around a groundwater crisis

Subsidence is often not entirely reversible, but groundwater harvesting can stop the problem and even cause the surface to rebound slightly. This was part of the story in 39 percent of the cases studied, including in places like Shanghai, Bangkok and Houston.

So why might groundwater harvesting be a problem? Some examples could simply be filed under “too much of a good thing”: flooding of tunnels or particularly low-lying areas and croplands. But there were also structural problems, as previously dry sediments became saturated and the land surface shifted upward. Some seismically active areas have even faced an increased risk of liquefaction during earthquakes.

Furthermore, chemistry can cause problems. Shallow pollutants and fertilizers were mobilized when the water table rose to meet them, for example. And the evaporation of waterlogged agricultural lands has caused a gradual accumulation of salts in the soil of parts of Türkiye and Iran.

The plan

Jasechko learned several lessons from comparing all these cases. First, most included at least two of the three common approaches he identified. Problems with complex causes require solutions on multiple fronts.

Another lesson is that the time it took to see groundwater trends change direction varied quite considerably. In some cases, water level data yielded results within a few years, but in others it took decades. Bangkok, for example, began introducing charges on groundwater use in the late 1970s, but it took more than 20 years before the charges became high enough to have an impact. And then there’s climate variability: dry or wet years can obscure the results of your actions.

Another lesson is that details matter. There may be areas where groundwater elevation above a certain level will cause problems, and it would be best to identify these in advance rather than through experience. And since every situation is unique, the best approach in each individual case will be a unique set of solutions.

At a fundamental level, this study reminds us that groundwater harvesting has arrivedit is therefore possible for communities to turn the situation around. So when we learn from history, we may find certain parts that we would actually like to repeat.

Science, 2026. DOI: 10.1126/science.adu1370 (About DOIs).