The world’s largest known fossil wateraquifer system. It is located underground in the Eastern end of the Sahara Desert and spans the political boundaries of four countries in north-eastern Africa. NSAS covers a land area spanning just over 2.6 million km2, including north-western Sudan, north-eastern Chad, south-eastern Libya, and most of Egypt.
Containing an estimated 150,000 km3 of groundwater, the significance of the NSAS as a potential water resource for future development programs in these countries is extraordinary. The Great Man-made River Project (GMMR) in Libya makes use of the system, extracting substantial amounts of water from this aquifer, removing an estimated 2.4 km3 of fresh water for consumption and agriculture per year. This system is primarily used to supply water in the Kufra oasis.
The riparian countries – Chad, Egypt, Libya and Sudan – of the aquifer system face similar problems of arid climate, scarce surface water resources, persistent droughts and fragile ecosystems. The aquifer is a critically important source of water in this arid desert region and will be increasingly in demand in the future. Hence, all four countries have given priority to linking the NSAS groundwater exploitation to national development strategies and plans. Growing pressures on the aquifer system pose threats to both the quantity and quality of the resource and could, if not appropriately managed, lead to transboundary/shared problems and tension.
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Article
Ancient Water Underlies Arid Egypt
A hidden trove of groundwater is left over from the last ice age.
Aside from the Nile River’s green corridor, much of northeastern Africa is desert. But the arid landscape hides a secret: Vast quantities of groundwater fill an underground aquifer that spans four countries.In the future, as Egypt’s population and agriculture expand, groundwater will become a more important resource.A new study using chloride isotopes to date the groundwater under Egypt’s Eastern Desert has found that the water in smaller, shallower aquifers is refilled by the larger, deeper aquifer, where vast quantities of groundwater date to the last ice age.
Most Egyptians live along the Nile and get their drinking and irrigation water from the river. Currently, just 7% of the country’s water usage is supplied by groundwater, but that number is expected to rise, said Mahmoud Sherif, a hydrogeochemist at the University of Delaware and lead author of the new study, published in Earth and Planetary Science Letters. “In the future, as Egypt’s population and agriculture expand, groundwater will become a more important resource.”
The research team set out to date the age of the groundwater under the Eastern Desert to determine the aquifers’ responses to climate conditions and the recharge rates of shallower formations called alluvial aquifers. “These aquifers are closer to the surface and easier to access than the deeper Nubian aquifer,” Sherif told Eos.
“We expected the water in the shallow aquifers to be less than 100 years old,” Sherif said, with the clock starting when the rainwater falls from the atmosphere onto Earth. Instead, some of the water samples were more than a thousand times that age.
The researchers used the radioactive isotope chlorine-36, which has a half-life of 300,000 years, to date groundwater samples collected from 29 wells scattered around the Eastern Desert. They found that the oldest samples in the alluvial aquifers were more than 200,000 years old. “This was really surprising,” Sherif said.
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International Waters Governance:
http://www.internationalwatersgovernance.com/nubian-sandstone-aquifer-system-nsas.html
UNESCO-IHP Groundwater Portal:
https://groundwaterportal.net/project/nubian-aquifer
