UK: Researchers from the British Geological Survey and University College London for the first time mapped aquifers, or groundwater, across the African continent. “The largest groundwater volumes are found in the large sedimentary aquifers in the North African countries Libya, Algeria, Egypt and Sudan,” the scientists stated in their paper published in journal ‘Environmental Research Letters’.
The researchers said the maps, based on existing geological charts from governments and hundreds of aquifer studies, are aimed at promoting a “more realistic assessments of water security and water stress”.
The researchers noted their new maps indicate that many countries currently designated as “water scarce” have substantial groundwater reserves.
The researchers estimated that reserves of groundwater across the continent are 100 times the amount found on its surface, or 0.66 million cubic kilometres. However, they cautioned, that not all these reserves can be accessed. Where they can, small-scale extraction using hand pumps would be better than large-scale drilling projects, which could quickly deplete the reservoirs and have other unforeseen consequences.
“Water levels deeper than 50 meters will not be able to be accessed easily by a hand pump,” said the study, led by Dr Alan MacDonald of the British Geological Survey. “At depths greater than 100 meters the cost of borehole drilling increases significantly due to the requirement for more sophisticated drilling equipment. However, our work shows that with careful exploring and construction, there is sufficient groundwater under Africa to support low yielding water supplies for drinking and community irrigation.”
The scientists stated that there are sufficient reserves to be able to cope with the vagaries of climate change.
Earlier, a NASA-led team used radar sounding technology to create high-resolution maps of freshwater aquifers buried deep beneath Earth desert.