Sahara's secret reservoir: Enough freshwater for a millennium buried under sands

Just a few thousand years ago, the region now known as the Sahara was a lush, vibrant savanna, teeming with numerous animal species and serving as a hospitable habitat for humans. Due to climate change, an expanse equivalent in size to Europe, which once brimmed with life, has transformed into a barren, inhospitable desert.

Surviving relics from those bygone days are the enormous water resources concealed below the desert sands in the eastern part of the Sahara - the Nubian Sandstone Aquifer System. For residents of countries such as Egypt, Sudan, and Libya, this is excellent news.

The volume of the water resources is extensive enough that, even considering population growth, there should be sufficient water to last a millennium. The team led by Mahmoud Sherif, a geochemist from the University of Delaware, estimates the reservoir could hold as much as 150,000 cubic kilometers of fresh, clean water, equating to approximately seven times the volume of the Baltic Sea. Remarkably, this water is safe to drink without requiring any filtration or purification.

However, extracting this water is challenging due the deposits' location, buried between layers of sand and rock one to three thousand meters (0.62 - 1.86 miles) beneath the earth's surface. Despite being extremely valuable and untainted, this resource exists outside the current hydrological cycle, making it, crucially, a non-renewable resource.

An effort to exploit this resource was once made by Libya when it began constructing the Great Man-Made River, a project costing nearly 20 billion dollars. Although the endeavor included a system of wells and pipelines to supply the country with water, it was never fully completed. Regardless, it currently provides almost half of Libya's drinking water.