Water experts have reacted cautiously to news that huge reserves of groundwater have been identified in Africa.
Scientists from the British Geological Survey (BGS) and University College London last week published a report claiming that there is between 0.36M.km3 and 1.75M.km3 of underground water in Africa, more than 20 times the amount stored in its lakes.
But the resources are unevenly distributed, with the largest volumes in North African countries like Libya, Algeria, Egypt and Sudan.
Reserves in this area, which are around 250m below ground, could be exploited on a large scale, but they have taken thousands of years to build up and are not being replaced, according to report author BGS hydrogeologist Helen Bonsor.
“In the north, where there are the largest groundwater reserves, there is no current rainfall, so that’s a finite resource,” she said.
“In sub-Saharan African there is less groundwater storage but that’s where rainfall is still occurring, and so those smaller groundwater stores are being replenished.”
The study suggests these reserves could support small scale, sustainable extraction using boreholes and hand pumps.
Mott MacDonald director James Montgomery told NCE: “The availability of low yielding sources to supply potable water to villages and communities is the basis of most of rural Africa’s existing water supply.”
“Many of the reserves quoted [in the report] have been known about for decades.
“It would be a mistake to think the issues of maintaining sustainable supplies to Africa have been solved in a stroke,” he added.
Bonsor said one aim of the study was to encourage national and regional research to inform planning policy.