How Government Policies Can Reverse Groundwater Depletion

According to a study published in Nature in January 2024, groundwater in aquifers worldwide is draining rapidly. Researchers find that groundwater is depleted in 30% of the world’s regional aquifers, and depletion has accelerated in the last 40 years.

Groundwater is the primary source of freshwater for many farms, homes, industries, and cities worldwide. However, climate change has brought more frequent and longer dry conditions and droughts, increasing reliance on groundwater.

Using both in situ data from 170,000 wells and 1,693 aquifer systems in more than 40 countries that cover 75% of global groundwater withdrawals and satellite observations from the Gravity Recovery and Climate Experiment (GRACE) satellite researchers were able to study and observe the groundwater depletion and recovery trends in the twenty-first century. To identify a trend, researchers measured groundwater levels with a time series that span eight years. 

In 30% of these depleting aquifer systems, the rate of decline in the early twenty-first century (from 2001 – 2100) has outpaced that in the late twentieth century (1980-2000).

However, not all groundwater levels are rapidly declining; for some, the depletion rate is slowing down, and others have reversed their water losses. “Our analysis of groundwater levels suggests that long-term groundwater losses are neither universal nor inevitable,” the researcher writes.

In 20% of the aquifer systems, groundwater level declines are slowing down, 16% have reversed, and 13% have continued to rise. Still, the number of aquifers experiencing a rapid decline in groundwater level depletion is greater. However, the data shows that a slowing down or reversing groundwater level is possible.

Government regulations and policies can slow or reverse groundwater level depletion. The study gave a few examples of this from around the world.

“In the Bangkok basin (Thailand), groundwater levels deepened during the late twentieth century but shallowed in the early twenty-first century. This reversal has been attributed to regulatory measures (groundwater pumping fees and licensing of wells). Another example is Iran’s Abbas-e Sharghi basin, in which twentieth-century groundwater-level declines were reversed by water diversion to the basin from the Kharkeh Dam. In other areas, groundwater deepening has been reversed following the implementation of managed aquifer recharge projects (for example, west of Tucson, Arizona). Recharge projects are sometimes only viable where excess surface waters are available, emphasizing the importance of coordinating groundwater and surface-water management. Nevertheless, these examples illustrate that sufficient scope and scale interventions can reverse declining groundwater trends.”

The Study concludes, “This widespread acceleration in groundwater-level deepening highlights an urgent need for more effective measures to address groundwater depletion. Our analysis also reveals specific cases in which depletion trends have reversed following policy changes, managed aquifer recharge and surface-water diversions, demonstrating the potential for depleted aquifer systems to recover.”

Read the whole study by clicking the link in the “Source” section below.