Aquifer Recoveries Show That Groundwater Depletion is Not Inevitable: New Study

  

      Groundwater supplies drinking water to about half of the world’s population and about 40% of the world’s irrigation water. Roughly a third of the world’s groundwater aquifers are being depleted faster than they are being recharged. Declining water tables exacerbate problems from drought, cause significant land subsidence, and contribute to coastal infiltration of saltwater.

     UC Santa Barbara professor Scott Jasechko details 67 cases of aquifer recovery in a study published in the journal Science. He found that most successes involved multiple intervention categories, and over 80% involved sourcing an alternative water supply. The paper gives insights to address declining water tables.

"The cases in this review are a reminder that groundwater depletion is not inevitable," said Jasechko, a professor at the Bren School of Environmental Science & Management. "They highlight how humans have solved this problem in different places around the globe."

     In a January 2024 paper in Nature, Jasechko and colleagues formed the largest global database of water table levels in aquifers. It includes 1700 aquifers around the world. Below, the graphic from the paper shows aquifers and the status of their water tables. 

     The paper sought to understand where groundwater levels were falling and rising and the reasons for water level recoveries. The three-year study utilized 300 million water level measurements from 1.5 million wells over the past 100 years, and most of the time was spent cleaning and sorting the data. According to Phys.org:

“The work revealed that groundwater is dropping in 71% of the aquifers. And this depletion is accelerating in many places: the rates of groundwater decline in the 1980s and '90s sped up from 2000 to the present, highlighting how a bad problem became even worse. The accelerating declines are occurring in nearly three times as many places as they would expect by chance.”

     As one would expect, groundwater is depleting at higher rates in arid areas.

“Groundwater declines of the 1980s and '90s reversed in 16% of the aquifer systems the authors had historical data for. However, these cases are only half as common as would be expected by chance.”

“This study shows that humans can turn things around with deliberate, concentrated efforts," Jasechko said.

     In a January 2024 article in The Conversation, the authors explained the study’s dual findings and put emphasis on further research into aquifer recovery case studies:

“Our study has two main findings. First, we show that rapid groundwater depletion is widespread around the world and that rates of decline have accelerated in recent decades, with levels falling by 20 inches or more yearly in some locations. Second, however, our research also reveals many cases where deliberate actions halted groundwater depletion. These results show that societies are not inevitably doomed to drain their groundwater supplies, and that with timely interventions, this important resource can recover.”

     They also pointed out that in heavily farmed arid areas, groundwater depletion was accelerated and presented serious concerns about future supply:

“In many locations, especially arid zones that are heavily farmed and irrigated, groundwater levels are falling by more than 20 inches (0.5 meters) per year. Examples include Afghanistan, Chile, China, Peninsular India, Iran, Mexico, Morocco, Saudi Arabia, Spain and the U.S. Southwest.”

     In the new study, two-thirds of the case studies of aquifer recovery included more than one replenishment strategy, and 81% included an alternative water source. 

     Some strategies are shown in the graphic below. The second graphic goes into more detail about these kinds of strategies.

     Sometimes, finding alternative water sources just moves the depletion problem to another nearby area, so that needs to be considered.

     Below, Jasechko gives a summary of his findings in ten key themes and insights into groundwater management:

     One example given in the Phys.org article is Beijing, China, where during the period of 1950-2000, groundwater levels dropped by a stunning 20 meters in some places. In 2003, the government began to construct canals and pumping stations. By 2015, it was delivering water to the city and surrounding areas from wetter regions farther to the south. The city also began using more reclaimed water, much of it allocated to environmental uses such as watering trees and grasslands as well as replenishing lakes and rivers. They also banned pumping the aquifers for industrial uses. This is an example of a multipronged approach that was largely successful. Shallow and deep aquifers have recovered, and land subsidence rates have dropped.

     Jasechko and Phys.org point out:

"An important question is: What scope and scale of intervention is required for depleted aquifers to start recovering?" he said. These are important questions for communities and resource managers who would like to improve the situation, but just don't have a sense as to what magnitude of intervention is required.

"This study can help create a menu of options for managers and stakeholders to consider as they develop locally relevant strategies to try to make things better," he said. These examples and analysis, he believes, can provide the activation energy to begin addressing this problem more widely.

"Groundwater depletion is widespread globally. These cases highlight that there are ways to turn things around," Jasechko said. "Globally, there are many more bad news cases than good news cases. Yet, I am somewhat encouraged by the clever ways that certain managers and stakeholders have addressed the problem of groundwater depletion in specific places, because they show that the menu of strategies is longer than I originally anticipated."

 

 

 

References:

 

Why some regions are winning the fight against groundwater depletion. Harrison Tasoff. Phys.org. March 20, 2026. Why some regions are winning the fight against groundwater depletion

Global cases of groundwater recovery after interventions. Scott Jasechko. Science. 19 Mar 2026. Vol 391, Issue 6791. pp. 1218-1228. Global cases of groundwater recovery after interventions | Science

Global groundwater depletion is accelerating but is not inevitable, say researchers. University of California - Santa Barbara. Phys.org. January 24, 2024. Global groundwater depletion is accelerating but is not inevitable, say researchers

Humans are depleting groundwater worldwide, but there are ways to replenish it. Scott Jasechko, Debra Perrone, and Richard Taylor. The Conversation. January 24, 2024. Humans are depleting groundwater worldwide, but there are ways to replenish it