Nubian Sandstone Aquifer System
The term Nubian Sandstone Aquifer (English Nubian Sandstone Aquifer ) is called a large underground water reservoir with fossil groundwater in the Nubian Desert. With a volume of approximately 373,000 km ³ (approximately 10% of the volume of the Mediterranean, and the estimates of the storage volume vary considerably ) this is one of the largest known aquifer in the world. It covers an area of about 150,000 square kilometers in an area which is spread over the states of Egypt, Libya, Sudan and Chad; his age is 4,500 to 5,000 years. The water -bearing rock layer, porous sandstone, lies at a depth of 800 to 4,500 meters. In some places, aquifers reach the surface and form the lakes of Ounianga and the small lakes in the wildlife reserve Fada Archei in the northeastern Chad Basin.
Formation
More recent theories assume that the fossil water reserves in Africa emerged in a Pluvial, the bottoms saved the seeped water.
Use, risks
Due to the prevailing hyperarid climate almost no groundwater recharge takes place in this aquifer system; its water level fell due to the massive use in the last years by about 60 meters; optimistic forecasts with continued use in contemporary style on the assumption that the aquifer will be exhausted in about 200 years.
The oases of the Western Desert in Egypt Bahariya, Farafra, Abu Minkar, Dakhla and Kharga are all in sinks, from which gushed artesian springs until about 50 years. Population pressure and the intensification of agriculture caused an overuse of resources, so that they eventually dried up. Thus began the Egyptian Ministry of Irrigation, from 1981 to promote fossil groundwater in the oases.
In the 1970s, several large irrigation projects were launched in the territory of Kufra Oasis in Libya, who became known primarily through the irrigated fields in circular form ( see also film Home by Yann Arthus -Bertrand ). The Libyan regime boasted about to have built a man-made river for irrigation and drinking water supply, accordingly, the project is also called Great man-made river project ( Great Man - Made River project, GMMRP or GMMR ).
The non-renewable fossil water reserves are also exploited for the supply and disposal of uranium mining by the AREVA Group in Niger.