But the scientists also warn that Africa faces more droughts because of climate change and could have 25 percent less water by the end of the century, setting the state for possible water wars.
Egypt and Ethiopia, for instance, are facing off over the long-contested waters of the Nile River because Addis Ababa is building a giant $4.3 billion hydroelectric dam, which will cut the flow to Egypt, whose 84 million people depend on the Nile to survive.
The U.S. global security consultancy Stratfor cautioned the September discovery of the aquifers in the drought-plagued Turkana desert of northwestern Kenya near the borders with Uganda and South Sudan raises "the possibility of cross-border conflicts over water rights in the future."
The Lotikipi Basin Aquifer and the smaller Lodwar Basin Aquifer were among five aquifers located by Radar Technologies International of France, in collaboration with the Kenyan government and the United Nations with funding from Japan.
The East African aquifers were discovered using advanced satellite technology and confirmed by drilling. The size of the other three Kenyan acquifers still has to be determined by drilling.
Lotikipi, roughly the size of Rhode Island, contains an estimated 7.3 trillion cubic feet of water with an annual recharge rate of 42.4 billion cubic feet through rainfall in Kenya and Uganda.
All told, some 8.8 trillion cubic feet of underground water was found, with an expected annual recharge rate of 110 billion cubic feet -- an amount roughly equal to 15 percent of the 741 billion cubic feet of water currently available to Kenya each year.
The Turkana region is populated largely by nomadic tribes, who lack regular access to water. Kenya's economic hubs of Nairobi and the Indian Ocean port of Mombasa are around the Lake Victoria and Athi basins, which hold around 60 percent of the country's water resources.
So there's likely to be considerable debate over how to use the new aquifers in terms of national development resources that Kenyan officials initially claimed could supply the entire country with water for the next 70 years.
But Stratfor observed that with a growing population already surpassing 41 million, Kenya, riven by tribal rivalries and heavily reliant on foreign aid for development, is likely to find the new water resources not enough to "support continued population and economic growth."
It noted: "Competition for the new reserves can be expected. Currently, agriculture dominates water usage, accounting for roughly 80 percent of Kenya's water consumption, but oil and manufacturing will likely vie for the resource. ...
"Sustainability will require improvements in both infrastructure and resource management, neither of which will come easy. ...
"Overuse of water resources by agricultural, municipal or oil sectors would further limit the region's potential for long-term growth," Stratfor observed.
Africa's water woes also have been mitigated by the July 2012 discovery of a major aquifer named Ohangwena II under the Namibia-Angola border on Africa's southwestern coast.
On the Namibian side, the 10,000-year-old aquifer covers an area roughly 43 miles by 25 miles.
Because of climate change over the eons that turned the Sahara into a desert, scientists say many of the aquifers deep under the sands were last filled with water 5,000 years ago.
Project manager Martin Quinger, from the German Federal Institute for Geoscience and Natural Resources, says the aquifer could supply northern Namibia "for 400 years" and will help people adjust to climate change.
The 400-year estimate is probably overly optimistic, but scientists writing in the journal Environmental Research Letters recently argued the total volume of water in African aquifers is 100 times the amount found on the surface and probably purer because it's untainted by pollution.
That could be good news for the estimated 300 million people on the planet who are believed to have no access to safe drinking water.
The BBC reported in April 2012 scientists from the British Geological Survey and University College London were able to map Africa's hidden underground water reserves.
Helen Bonsor of BGS estimates there's enough water there to "provide a buffer to climate variability."