Highlight of piezometric fluctuations of groundwater through piezometrics network in the region of biskra (Algeria)

The Aquifer System of the Sahara shared by Algeria, Libya and Tunisia contains huge reserves of water, characterizing by a lower renewable resources. It consists of two aquifer levels, the Continental Intercalary and the Terminal Complex. The reserves are estimated at 30.109 m3 (SASS, 2003). The last thirty years have shown an increase in exploitation of these aquifers, with an annual throughput of 0.6 109 m3 in 1970 to a rate of 2.5 109 m3 in 2005, indicating overexploitation. The Biskra region belongs to this group of aquifers. It has in recent years, a large hydro-agricultural development with a growing population, resulting in a considerable increase of water demand. For the setting up of a monitoring system for exploitation of water resources in the Saharan zone, the ANRH services in collaboration with CRSTRA have established a monitoring network to monitor changes in groundwater piezometric level of Terminal Complex. This includes 23 piezometers located in different exploited aquifer system. The piezometric mapping shows a drawdown of about 20 m in lower Eocene in the localities of Tolga and Doucen. This drawdown differs from an area to another in the Mio-Pliocene aquifer system, and it is 30 m between Ourellal and Sidi Okba and about 6 m in Zribet El Oued.