The North Western Sahara Aquifer System (NWSAS), better known under the acronym SASS for its French name “Système Aquifère du Sahara Septentrional”, is a large aquifer shared by Algeria, Libya, and Tunisia. The NWSAS designates the superposition of two main deep aquifer layers: the Intercalary Continental (IT) in the bottom and the Terminal Complex (TC) on the top.
The North Western Aquifer System covers an area of more than one million square kilometres and contains considerable but partly renewable and inappropriately used water resources.
The SASS zone covers different eco-regions varying from desert zones (with annual rainfall rate less than 100mm and an evapotranspiration rate higher than 3000 mm) to arid zones (annual rainfall of 100-200 mm and an evapotranspiration rate of 2000-2500 mm).
The use of this aquifer dates back to many years, first by creating surface wells and “foggaras” (ancient type of water supply) and later by constructing “boreholes” that depth exceeded in certain cases one to two thousand meters.
The intensive use of the SASS by the three countries has caused stress on the resource, increasing the risks of saltwater intrusion and salinization, loss of artesian pressure, the depletion of natural outlets and the lowering of the water table. In order to mitigate, and to well control further the major transboundary risks, Algeria, Libya and Tunisia created “The Consultation Mechanism” an institutional dialogue framework for sustainable management of shared groundwater resources.
The SASS project has currently completed its third phase (SASS III 2007-2013) entitled “Operational recommendations for sustainable water resources management of the North-western Sahara Aquifer System”.
Objectives and beneficiaries
- Identifying major transboundary risks resulting from overexploitation and climate change.
- Elaborating indicators for the monitoring of water resources development and vulnerability.
- Restoration of the initial flow of ancestral groundwater catchment system -- “the fogarras”-- using solar-powered pumping.
- Restoration of the oasis system through agricultural techniques that have proven efficiency in terms of water use and return on investment.
- Rationalization of land and water management
- Restoration and protection of declining farming systems in arid regions
- Valorization of geothermal water in irrigating off-season crops
- Rehabilitation of irrigated lands affected by salinization and waterlogging (hydromorphy)
- Using desalinated brackish water in irrigation.
The trial of enhanced water and soil management techniques was conducted in 6 demonstration pilots hosted by privately-owned farms in the three SASS riparian countries, namely Algeria, Libya and Tunisia. Regional workshops and field trips allowed for cross-fertilization and sharing of lessons learned and best practices among the participating farmers and national experts from the three countries.
Strong points of the practice
The project’s demonstration pilots hosted by privately-owned farms provided compelling evidence of the feasibility and the economic viability of sustainable water and soil management as an alternative to the status quo characterized by vulnerability and rapid degradation.
By conducting a survey on a 3,000 strong sample of farmers operating in the SASS basin area, the socio-economic dimension of the project provided insights into demand and how a better valorization and efficiency in the use of the water resources can be obtained through a number of instruments such as pricing, fiscal incentives, etc.
Expected results and benefits for climate change adaptation and mitigation
- Mitigation of water and soil degradation process.
- Integration of socio-economic information into water policy making.
- Hydro-economic model as a decision-support tool
- Protocol for a concerted vision of sustainability in the basin to be implemented by the SASS Consultation Mechanism.
Replicability potential of the practice
High-potential of replicability across the basin with actual demand from the riparian countries, and with possible replication in other basins.