More frequent droughts and intense rainfall driven by climate change are increasing pressure on global water resources prompting experts to promote groundwater storage as a sustainable solution for managing both water scarcity and flooding according to a report by Deutsche Welle.
Groundwater, which supplies nearly half of the world’s drinking water is being depleted at an alarming rate as extraction has tripled over the past five decades. Researchers estimate that more than two billion people and around 40 per cent of global agricultural production now depend on overexploited groundwater reserves.
The report highlights that prolonged droughts, combined with rapid urbanisation and increasing paved surfaces are reducing the amount of rainwater that naturally infiltrates the soil to recharge aquifers. Even heavy rainfall often results in surface runoff instead of replenishing groundwater.
To address this challenge, researchers at the Technical University of Munich have developed a “Smart Storm Water Storage” system that combines flood management with groundwater recharge. During heavy rainfall, excess water is collected in retention basins, purified, and injected deep underground through infiltration wells. The stored groundwater can later be pumped for drinking water and irrigation during dry periods.
Similar groundwater recharge initiatives are being implemented globally. In Namibia capital, Windhoek treated wastewater and reservoir water have been injected into aquifers since 2002 to replenish groundwater supplies while reducing evaporation losses compared to surface reservoirs.
California has also made managed aquifer recharge a key part of its climate adaptation strategy. According to the report, the state recharged more than 4.1 million acre feet of water into aquifers in 2023 by diverting excess rainwater and floodwater into recharge basins.
The report also outlines nature-based solutions such as restoring rivers and reconnecting them with their floodplains. During floods, restored rivers allow excess water to spread into adjacent wetlands where it naturally filters through the soil and replenishes groundwater while reducing flood risks.
Other approaches include targeted flooding of agricultural fields during extreme rainfall, bank filtration systems that naturally purify river water as it seeps underground and the construction of sand dams in arid regions such as Kenya to improve groundwater storage.
Experts say groundwater storage offers a long term strategy for strengthening water security because water stored underground experiences significantly lower evaporation losses than surface reservoirs. As climate change intensifies weather extremes, expanding groundwater recharge and sustainable water management will become increasingly important for ensuring reliable water supplies while reducing flood risks.