A new global study has identified how quickly groundwater systems recover after prolonged droughts offering a way to identify regions where groundwater reserves may be particularly vulnerable.
Hydrologist Sandra Hauswirth of Utrecht University developed a classification method using a high resolution global groundwater model with a spatial resolution of one kilometre. The model was used to examine groundwater drought events around the world and assess how groundwater systems respond during drought and recover afterward.
The study found that 57% of locations have resilient groundwater systems that recover rapidly and strongly following drought. About 15% were classified as vulnerable, while 26% were identified as unstable, with repeated droughts reducing their ability to recover and causing stronger impacts on groundwater systems.
Climate conditions were found to be an important factor in groundwater recovery, while local geology and landscape also influence how systems respond to drought. Human activities, particularly groundwater extraction, can further affect recovery.
Regions with heavy groundwater use and declining groundwater levels, including parts of California, Spain, India and the Northern China Plain, showed a more complex mix of recovery patterns. Such areas contained more vulnerable and unstable groundwater systems associated with groundwater abstraction.
Researchers said the findings could help policymakers identify regions at risk of reaching critical groundwater thresholds and develop targeted strategies for sustainable water management.
The current research focused mainly on geographical patterns of groundwater recovery. Follow up studies will examine how recovery patterns change over time and how groundwater systems may respond to future climate conditions.