The researchers used data from NASA’s GRACE satellites to track total water storage in the aquifers from 2002 to 2020. The result is an 18-year timeline that provides a longer term perspective on water trends and what drives them.
Sustainable water means a nation that can be water self-sufficient ensuring there is enough water to meet multiple needs, from agriculture to municipal and industrial.
Most cities in Africa rely on surface water from lakes, rivers and human-made reservoirs. But there is an abundance of groundwater across the continent, with annual groundwater recharge being comparable to the volume of water that flows through the Congo, Nile, Niger and Zambezi rivers each year combined.
In sub-Saharan Africa, the study found that most aquifers increased their water supply during the period. However, the data show that water levels frequently underwent big swings, too.
Sustainable water systems should provide adequate water quantity and appropriate water quality for a given need, without compromising the future ability to provide this capacity and quality, according to the IWA.
The study found that these swings closely tracked with climate patterns that are known to influence rainfall in the region, such as El Niño, the Indian Ocean Dipole (IOD) and La Niña.
El Niño and IOD generally increase rainfall in eastern Africa and decrease rainfall in southern Africa, whereas La Niña generally has the opposite effect.
Groundwater could be the answer, but it is not always easily accessible. Sometimes it doesn’t replenish quickly enough, it is deep below the ground surface, and other times, especially when aquifers are close to the sea, they might become saline.
Tapping into groundwater can help communities in Africa diversify their water supply and strengthen drought defenses.
The data showed that even though certain Sub-Saharan aquifers sometimes faced water level declines, the levels consistently and quickly recovered during rainy periods, which helps guard against overuse, said lead author Bridget Scanlon, a senior research scientist at the UT Bureau of Economic Geology.
We need better use of groundwater, a better understanding of groundwater, and we need to start taking groundwater more seriously.
Access to clean drinking water is a human right, and governments have the responsibility to provide their citizens with safe, clean, accessible and affordable drinking water for all. Yet this is far from reality in many nations across the globe.