Review of Interventions to preserve Groundwater

 Global cases of groundwater recovery after interventions | Science

How communities are reversing groundwater depletion: lessons from 67 global success stories | UC Santa Barbara - Bren School of Environmental Science & Management

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.