The Iullemeden Aquifer System (IAS), shared by Mali, Niger and Nigeria, is a sub-regional aquifer system in West Africa sahelian zones. The area is 500 000 km². The annual rainfalls mean values change from North to South less than 100 mm to 800 mm.

The Iullemeden Aquifer System is under environmental threats caused by: 1) climate changes; 2) growing population pressure: 15 million in 2000, the double in 2025; 3) Groundwater over-exploitation: 50 million m³ in 1970, 180 million m³ in 2004; 4) human induced water pollution.

In order to address transboundary risks associated with these threats in a strategic manner, the project adopts a risk-based management approach. The project is aimed at establishment of a joint mechanism and cooperative framework for: (a) identification of transboundary risks and uncertainty issues; (b) formulation of joint risk mitigation and sharing policy; and (c) joint policy implementation through a joint IAS legal and institutional consultative mechanism. These components will be supported by awareness raising, public participation and communication.

The main achievements are: 1) major transboundary risks identified, 2) common data base elaborated (more than 17000 boreholes), 2) Geographic Information System developed, 3) Groundwater model developed, 4) Iullemeden website elaborated, and 5) a clear consensus on the need for, and on the structure and mandate of, the consultative mechanism, and on the approach to be followed for its establishment.

The perspectives are: 1) formulating the Strategic Action Programme, 2) improving data and information, 3) assessing and managing surface water and groundwater, and 4) implementing the regional consultative mechanism.

The project is managed through the project steering committee by the three governments with the Sahara and Sahel Observatory as the Executing Agency.