As climate change makes rivers and lakes increasingly unreliable across Africa scientists are turning their attention underground. Researchers are mapping the continent’s vast groundwater reserves to help countries secure drinking water, support agriculture and strengthen resilience against droughts in a warming climate.
Africa is estimated to sit atop around 0.66 million cubic kilometres of groundwater, nearly 20 times the amount of freshwater stored in all of the continent’s lakes combined. Despite this enormous resource, around 400 million people in Africa still lack access to basic drinking water services highlighting the need for better management of underground water supplies.
Digital Mapping to Identify Safe and Sustainable Groundwater Sources
A team of hydrogeologists and water policy experts working on the Groundwater for Advancing Resilience in Africa project is developing a continent wide digital map to identify areas where groundwater can be safely extracted, naturally replenished and protected from pollution.
The project combines hydrogeological information, such as groundwater availability and recharge rates, with population, agriculture and land use data. Researchers are also conducting field surveys to ensure groundwater is used sustainably without depleting aquifers.
The latest findings suggest that around 94 million rural Africans live in areas where groundwater could provide safe drinking water, while nearly 333 million people live in regions where groundwater could sustainably support irrigation.
Not All Underground Water Can Be Replaced
Scientists caution that not all groundwater resources are renewable. In North Africa, countries including Libya, Algeria and Egypt rely on deep sedimentary aquifers that contain “fossil water” deposited more than 10,000 years ago when the Sahara was much wetter. Since these aquifers receive virtually no modern rainfall, the water cannot be naturally replenished once extracted.
Excessive pumping can also damage aquifer structures, causing land subsidence as underground layers collapse.
In contrast, much of sub Saharan Africa depends on groundwater stored in fractured crystalline rocks. Although these aquifers generally produce lower water yields, they recharge during the rainy season, making them an important and renewable source of water for rural communities and small-scale farming.
Monitoring Shared Aquifers Across Borders
The project is also focusing on aquifers shared by neighbouring countries, including the Mono River Basin between Togo and Benin and the Shire River Basin shared by Malawi and Mozambique. Researchers are installing and upgrading monitoring boreholes equipped with sensors to measure groundwater levels, temperature and salinity.
Scientists say cross border cooperation is essential because excessive groundwater extraction in one country could reduce water availability or affect water quality in another.
Researchers believe the completed groundwater map will help African governments identify areas suitable for sustainable water development, monitor pollution risks and guide long-term investment in climate adaptation. As rising temperatures continue to increase drought risks across the continent, experts say protecting and responsibly managing underground water resources will become increasingly important for ensuring reliable water supplies for millions of people.