Deep in the rock formations under the Sahara there is an enormous water reservoir: the Savornin Sea. These resources feed the isolated oases and artesian springs. Newest research has shown that the ground water under Egypt and Libya is up to one million years old.

According to latest research, this reservoir originated from rain that fell in the midst of the Sahara in the mountainous region between Libya, Egypt, the Sudan and Chad up to one million years ago. According to researchers of the University Of Illinois in Chicago, this reservoir has its origin in humid Atlantic air masses. Since then, the groundwater has been moving forward about one to two meters per year from Nubia (the area between Aswan in Egypt and Karima in Sudan) towards the north.

It is estimated that the rock formations under the Sahara hold about 800,000 km³ of ground waters, which is the quantity of water that the River Nile carries in 500 years. For about 60 years, especially Libya and Egypt have been using this groundwater on a large scale for irrigation projects.