Global cases of groundwater recovery after interventions | Science
Global
groundwater depletion is accelerating, but is not inevitable | The Current
Scott Jasechko, Global cases of groundwater recovery after interventions.
Science 391,1218-1228(2026).DOI:10.1126/science.adu1370
The article below is excerpted from the article cited above
and the UC Santa Barbara press releases linked above.
Groundwater supplies about 50% of the drinking water for the
people on our planet. In addition, groundwater also supplies 40% of the
irrigation water that feeds the people. Groundwater is essential. However, we
are using groundwater at an unsustainable rate-faster than it is being recharged.
The result is that mankind is depleting groundwater reserves at an accelerating
rate.
In 2024 Scott Jasechko, an associate professor in the
university’s Bren School of Environmental Science & Management, and his
team at UC Santa Barbara compiled the largest assessment of historical assessment
of historical groundwater levels around the world, spanning nearly 1,700
aquifers and 300 million water level measurement. That work presented a picture
of dwindling groundwater resources and accelerating declines. But it also found
that there are places where groundwater levels have stabilized or recovered.
Groundwater declines of the 1980s and ’90s reversed in 16% of the aquifer
systems the authors had historical data for.
That finding served as the basis for the current study which
looks at the success stores to understand the strategies that achieved them and
might be applicable in other areas. Groundwater is the savings account for our
fresh water resources. It is replenished by deposits from rain, snowmelt and
surface infiltration. Communities can spend a lot of money building
infrastructure to hold water above ground. But if you have the right geology,
you can store vast quantities of water underground, which is much cheaper, less
disruptive and less dangerous than building dams. The stored groundwater also
supports the region’s ecology. Groundwater recharge can store six times more
water per dollar than surface reservoirs.
Groundwater recovery can benefit economies and ecosystems.
The benefits of groundwater recovery can include (i) halting land subsidence,
(ii) slowing seawater intrusion, (iii) reducing drought vulnerability, (iv)
restoring groundwater-dependent ecosystems, and (v) improving groundwater
accessibility halting land subsidence,
However, there are also downsides to groundwater recovery.
In some cases, recovering groundwater levels have introduced new challenges,
such as (i) intensified flood hazards, (ii) compromised building stability,
(iii) heightened liquefaction risks, (iv) degraded agricultural soils, and (v)
increased pollution exposure
Right now, groundwater is being overdrawn. We can address
these by enacting policies and creating infrastructure to reduce the demand on
groundwater. Alternative water sources can offset groundwater demand or even be
used to recharge the groundwater aquifer. The current study tries to organize
67 unique combination of factors to identify trends. They found two-thirds of
the cases involved interventions from multiple categories, but finally broke
the strategies into three categories.
Alternative water supplies
81% of the groundwater success stories included an
alternative water source that helped offset groundwater demands. Professor Jasechko
suspects part of this strategy’s appeal is that it requires the least
behavioral change, the communities did not have to reduce total water use. But
accessing alternative supplies is often expensive and can end up displacing the
issue to another location.
Policy and market interventions
In contrast, policy changes benefit from low overhead and
energy costs. They also most directly target the behaviors that led to drawdown
in the first place. However, they often have major impacts on local economies
that have relied on groundwater use for a long time.
Artificial groundwater recharge
Groundwater recharge can eliminate the need to reduce
pumping, but the water needs to come from somewhere, and getting it into the
aquifer requires energy. In addition, it potentially introduces contaminants
into the aquifer.
Dr. Jasechko summarized his findings among the 67 cases of
groundwater recovery reviewed into 10 themes. These include (i) the prevalence
of cases involving multiple interventions, (ii) the high number of cases
involving alternative water sources, (iii) reductions in pumping in some cases,
(iv) the importance of sound implementation and enforcement strategies, (v) the
possibility for groundwater recovery to begin shortly after some interventions,
(vi) the potential upsides to gradual policy implementation, (vii) spatial
variability in groundwater recovery trends, (viii) the impermanence of
groundwater recovery, (ix) the importance of considering groundwater
quality, and (x) direct and indirect impacts of climate variability on
groundwater levels.
![]() |
| Jasechko et al |
First, two-thirds of the groundwater recovery cases involve two or more of the three types of interventions (i.e., alternative water supplies, policy or market changes, and artificial recharge). Most (81%) groundwater recovery cases involve access to alternative water sources to offset groundwater demands. These alternative water sources can be from nearby surface water, from recycled municipal water, from interbasin surface water transfers, or from reductions in upstream river diversions to enable more river water to reach a depleted aquifer farther downstream.
Groundwater recovery often coincides with reduced
groundwater withdrawals. In some cases, groundwater withdrawals declined after
policy . In other cases, groundwater withdrawals declined after the shutdown or
relocation of industries or the reduction in irrigated acreage as cultivated
lands were urbanized.
The magnitude of groundwater recovery can vary widely within
a given area. Further, groundwater recovery is not always ubiquitous, with some
monitoring wells recording groundwater storage increases but others capturing
continued declines. Ground subsidence from excessive groundwater withdrawal was
not reversed, it was only slowed or stalled.
Groundwater-level trends in shallower unconfined aquifers were
found to differ from deeper confined aquifers because shallower and deeper
aquifers often have different storage coefficients and different rates of
groundwater recharge and groundwater withdrawals. The examples discussed in the paper (especially the detail provided on Be
This study is not a guarantee that any particular
intervention will work elsewhere. It does not perform causal inference, but it
provides what Dr. Jasechko calls a "menu of options" for resource
managers, backed by documented outcomes from real-world cases across six
continents. Dr. Jasechko’s collaborator, UC Santa Barbara professor Debra
Perrone, is now working to build a comprehensive database of all locations
where interventions have been attempted, including those that failed, which
would enable more systematic analysis of what works and why.







