ABSTRACT
The Nubian aquifer system in Egypt is formed by pre-Tertiary sediments and is part of the Nubian aquifer system of the east Sahara, which also includes the Kufra basin in southeast Libya and northeast Chad and parts of north Sudan. Using radiocarbon age-dating and the stable isotopes deuterium and oxygen-18, it is proven that the groundwater in the Nubian aquifer system in Egypt is fossil, no recent formation is detectable. The Nile river will need just more than 500 years to discharge the water mass of the Nubian aquifer system in Egypt. Piezometric measurements certainly prove a regional gradient of the groundwater head and therefore a regional groundwater flow exists in the Nubian aquifer, which superposes the stationary unloading of the system. The discharge by leakage is proven in the northern part of the Nubian aquifer system only, but it has to be assumed that leakage takes place in all areas where the aquifer is confined.
