Searching for oil in the 1950s, prospectors discovered huge supplies of ancient water under the Sahara. The Great Man-Made River (an enormous network of underground pipes) now brings that water to the major cities of Libya.
The Nubian Sandstone Aquifer System contains “fossil” water left over from the last ice age. The pipes that extract and transport it stretch 2,820km from the aquifer to farms in northern Libya – making this the largest irrigation project in the world.
The river moves 6,500,000 m3 every day. By my back-of-the-envelope calculations, that’s 2,600 Olympic swimming pools of water. Every day. The aquifer is one of the largest in the world, and the amounts being drawn are supposedly not enough to deplete it in a thousand years. Already the impacts are being felt, though: the lake in the Kufra oasis (directly over the aquifer) has dried up.