Bienvenue à l'OSS - Welcome to OSS - The North-Western Sahara Aquifer System

The North-Western Sahara Aquifer System (NWSAS) — Système Aquifère du Sahara Septentrional (SASS) in French— covers a total area of over one million km²: 700,000 km² in Algeria, 80,000 km² in Tunisia and 250,000 km² in Libya. It contains sedimentary deposits which, from bottom to top, have two main levels of aquifers, the Intercalary Continental (IC) and the Terminal Complex (TC).

Withdrawals growing apace

Over the last 50 years, withdrawals of groundwater from the Algerian and Tunisian parts of NWSAS have risen sharply.
The present withdrawal rates, measured in 2000, are 550 hm³/yr in Tunisia, 1,5 hm³/yr in Algeria, and 450 hm³/yr in Libya.

The NWSAS Map

Agriculture accounts for 80% of total withdrawals and the three countries are expected to boost this further in coming years. From an estimated 0.6 billion m³in 1950, withdrawal has risen, in 2000, to 2.5 billion m³ pumped from over 8,800 water points.

Trends in withdrawals

The impacts go well beyond national borders and have so far led to a drop in the piezometric level, not to mention the degradation of water and soils. In ecological and economic terms, this situation is exacerbating desertification, poverty and scarcity of freshwater. Falls in agricultural production have also been recorded.

Addressing the problem together

The three NWSAS countries—all OSS members—came together under the aegis of OSS and embraced an approach of joint management. This approach is based on an in-depth knowledge of the aquifer, including projections and simulations of the impacts intensive withdrawal will have.
NWSAS is crucial to development in the North-Western part of the Sahara desert. Whereas in the recent past the aquifer once served only for oases irrigation (not forgetting the days of blooming extensive agriculture in the Sahara of yore), NWSAS water will now be crucial to secure food for a growing population close to, and even far beyond its borders, and to meet the demands of agriculture, industry and construction.