Managing Hydrogeological Risk in the Iullemeden Aquifer System

The Iullemeden sedimentary groundwater basin is located in Mali, Niger and Nigeria with minor, non-connected sections in Algeria and Benin. The aquifer system, which covers an area of 525 000 km2 with 31 000 km2 in Mali, 434 000 km2 in Niger and 60 000 km2 in Nigeria, represents one of the major freshwater reservoirs of West Africa and is linked to many humid areas and ecosystems. The following categories of environmental threats to the aquifer and the related ecosystems have been identified: (a) land use change in recharge areas and humid zones of the IAS, (b) climatic change, and (c) over-extraction and human-induced water pollution and water and land salinization.These threats/risks will be addressed by the project through the establishment of joint mechanism and cooperative frameworks for: (a) identification of transboundary risk and uncertainty issues, (b) formulation of joint risk mitigation and sharing policy; and (c) joint policy implementation through a joint IAS legal and institutional cooperative framework. The scope for management of transboundary risk and conflict in the IAS is constrained by the scientific uncertainty on the aquifer system and by the impacts of climatic change. Further causes for indecision relate to social and policy uncertainty and unawareness. To address these risk and uncertainty aspects the project will adopt a risk-based management approach. The emphasis can be expected to be on preparedness, responsibility, with monitoring and feedback to jointly address, mitigate and share risk and reduce uncertainty.