The North-Western Sahara Aquifer System refers to the superimposition of two thick aquifer layers:
- The Intercalary Continental (IC) formation, which is the thickest and has the greatest expanse, and
- The Terminal Complex (TC) which is heavily exploited in the Algero-Tunisian Chotts region and in the Gulf of Sirte in Libya.
Potential abstractions from these aquifers are limited first of all by economic constraints although the main constraints at present stem from environmental risks connected to the exploitation and vulnerability of Saharan watertables. The System covers more than a million km2 (1,800 km E-W, and 900 km N-S) of which 60% is in Algeria, a little less than 10% in Tunisia, and 30% in Libya.