International Waters learning Exchange & Resource Network

Enhancing the sustainable management of Senegalo-Mauritanian Aquifer System to ensure access to water for populations facing climate change (SMAS)

Project Objective

Foster multi-country cooperation and institutional capacity for the protection and sustainable management of the transboundary Senegalo-Mauritanian aquifer system and its dependent ecosystems in order to improve water and food security, and resilience to climate change.

The Senegalo-Mauritanian transboundary aquifer System (SMAS):

The Senegal-Mauritania Aquifer System (SMAS) extends over a total area of 300,000 km2 and is shared by four countries – Gambia (9,900 km2), Guinea Bissau (20,100 km2), Mauritania (111,000 km2) and Senegal (159,000 km2) – with a coastal line of 1,400 km. It lies approximately between 10° (southern limit) and 21° (northern limit) north latitude. The aquifer area/basin is crossed by two important transboundary watercourses, the Senegal - and the Gambia Rivers.

The Senegalo-Mauritanian aquifer system is composed of three major aquifers i.e. the Maastrichtian (lower aquifer) and the Paleocene (middle aquifer), which are hydraulically connected, and the upper superficial Quaternary aquifer. Due to the structure of the horst and graben system, these aquifers are also compartmentalized into three hydrogeological units, i.e. the Diass compartment in the center, the conned Sébikotane compartment in the West, and the conned/unconned Pout compartment in the East. The predominant source of recharge is through precipitation in the aquifer area. The natural discharge mechanism is through river base ow in Gambia, through discharge of springs in Mauritania, and through submarine outow in Senegal.  The climate in the area is Saharan and desert climate in the North (average annual rainfall less than 100 mm/year) and a humid tropical climate in the South (average annual rainfall more than 1,200 mm).

This project will mainly focus on strengthening knowledge of the Senegal-Mauritanian aquifer as a whole with the development of a Transboundary Diagnostic analysis and a participative, inclusive multistakeholder process for the establishment of a Strategic Action Plan for the sustainable and efficient use of the aquifer’s resources. These TDA/SAP tools will support the regional governance framework for cooperative and sustainable management (science and hydrodiplomacy). This level of intervention will be the first on a regional scale for this particular water body and countries in the basin have repeatedly requested assistance to operationalize such an initiative. In this context, the 4 riparian countries had ocially mandated the Sahara and Sahel Observatory (OSS) in 2003 to draft a request for funding of such support. A rst draft was elaborated in 2004. Then, several nancial partners was approached with this concept note (2014-2015) such as the DDC-Suisse, the FFEM (French GEF), AfDB, Canadian Cooperation, etc. without success because of change of strategy or other internal factors. A “Writeshop” workshop was organized in May 2017 with the countries and resulted in the development of a project concept note entitled: “Master Plan for Development and Sustainable Management of Shared Water Resources in the Senegalo-Mauritanian Basin: Satisfaction of water needs / Adaptation to climate change in the region”. The AfDB has maninfested interest in may 2021 in supporting the Master plan development of the SASM.


Senegalo-Mauretanian Basin

Africa , Western Africa

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Documents & Resources
General information
GEF ID 10784
Project type Full-Size Project
Status active (Project Approved)
Start Date 01 jan. 2023
End Date 31 des. 2025
GEF characteristic:
Focal Area International Waters
GEF Allocation to project USD 3 150 000
Total Cost of the project: USD 51 480 000
Gambia , Guinea-Bissau , Mauritania , Senegal , Regional

UN Environment (UNEP)

Project contacts
Caroline Okana Programme Assistant