Figure 1 : Location map of the North Sahara Aquifer System (SASS).

The project was executed by the Sahara and Sahel Observatory (OSS) with the support of the European Space Agency (ESA), and funded by the African Water Facility (AWF) for a duration of 18 months. The objectives of the project were to: (i) optimize the use of satellite data for the knowledge and management of the SASS aquifer shared by Algeria, Libya and Tunisia; (ii) provide the national agencies in charge of water management in the SASS countries with tools to strengthen and improve the consultation mechanism for an efficient and sustainable management of the shared water resource; (iii) to develop the capacities of the national agencies in the use of satellite data and the appropriation of these new technologies in order to obtain reliable data and information quickly and at a lower cost; and (iv) to ensure the replication to other African basins.
The project has thus contributed to strengthen the capacities (use of satellite and geographic data) of the services in charge of water management in the countries concerned by the SASS aquifer system. It has also provided tools to these countries to better identify the uses, and pressures exerted by both population and climate change on the aquifer system.
GEO-AQUIFER has thus implemented innovative technologies (satellite images), and has contributed to the strengthening of national capacities in a perspective of sustainability and reinforcement of the SASS concerted consultation mechanism.

Responsible entity

The Sahara and Sahel Observatory (OSS) is an international organization that operates in the arid, semi-arid, sub-humid and dry areas of the Sahara-Sahel region. Created in 1992, the OSS has been based in Tunis (Tunisia) since 2000. OSS has 26 African countries and 13 organizations among its members. OSS initiates and facilitates partnerships around common challenges related to shared water resources management, implementation of international agreements on desertification, biodiversity and climate change in the Sahara-Sahel region.

The main actions carried out by the OSS are

• The implementation of multilateral agreements on desertification, biodiversity and climate change;
• The promotion of regional and international initiatives related to environmental challenges in Africa;
• The definition of concepts and harmonization of approaches and methodologies related to sustainable land and water resources management and climate change.

OSS necessarily relies on knowledge transfer, capacity building and awareness raising of all stakeholders.
OSS activities and projects are financed respectively by voluntary contributions from member countries, and by grants and donations from development partners. With effective governance mechanisms and a competent, multicultural and multidisciplinary team, OSS makes a high value-added contribution to the international and African institutional landscape.

Institutional setting

The GEO-AQUIFER project is in line with the 2010 OSS strategy and the priorities of its “Water” program, which in its initial phase focuses on large transboundary aquifers in Africa. The project is consistent with the AWF’s areas of intervention, namely the management of transboundary water resources by supporting the joint development of shared waters and by supporting the improvement of knowledge in the fields of information systems and water resources management. GEO-AQUIFER is also part of the 2005-2009 operational program of the African Water Facility, by improving the framework of knowledge and concerted management of the SASS aquifer system shared by Algeria, Libya and Tunisia. The project is also perfectly in line with the NEPAD (New Partnership for Africa’s Development) priorities of integrated management of transboundary water resources and with the poverty reduction strategies of the SASS basin riparian countries, which have made water resources management a priority for sustainable development.

Geographical setting

The GEO-AQUIFER project covers the Northern Sahara Aquifer System (SASS) and the Tunisian-Libyan coastal aquifer of the Djeffara. The SASS covers more than one million km2 in Algeria, Tunisia and Libya. The extension and the thickness of the layers have favored the accumulation of considerable reserves, which are renewed little and are exploitable only in part. Over the last 40 years, the annual exploitation of the SASS has increased fivefold, reaching 3 times the average level of its natural recharge, and the aquifer is facing several major risks: strong transboundary interference, salinization of water, disappearance of artesianism, drying up of outlets, and excessive pumping heights. The Djeffara refers to the Tunisian-Libyan coastal plain, containing an aquifer system whose continental part extends over 40,000 km2. In terms of risk, the Djeffara is distinguished by a pronounced level of alert: in 40 years, withdrawals have also increased fivefold. This has resulted in significant drops in the water table in the coastal areas where exploitation is concentrated with very dangerous salt water intrusions.

Detailed explanation

The technical developments made during the project are:

• The extension of the digital mapping of the land use of the AQUIFER project;
• The creation of surface water maps on the SASS-Djeffara basin (Algeria, Tunisia, Libya);
• The elaboration of detailed land cover maps and land cover change maps on about 15 sample areas;
• The extension of the DTMs of the AQUIFER project and derived products on the SASS-Djeffara basin;
• The creation of a hydro-geographic repository on the SASS-Djeffara basin, a regional virtual globe, and a data dissemination tool;
• The development of capacities with the continuation of the trainings undertaken following the AQUIFER project, in particular in the techniques of production, management and exchange of geo-scientific data or research support.

Future outlook

In the near future, the OSS intends to replicate GEO-AQUIFER in other basins, thus fulfilling its vocation as a partnership platform and center of excellence for sustainable development in Africa. At the end of the project, a number of challenges remain:

• better knowledge of the irrigated perimeters on the whole Libyan Djeffara;
• better knowledge of the water withdrawals on the SASS and the Djeffara;
• full access to the possibilities offered by the GEO-AQUIFER website;
• better use of geo-scientific data and satellite images for the management of water resources and the ordinary functioning of the SASS Consultation Mechanism.

All these challenges, which are natural extensions of the project, should be part of future cooperation programs between the Sahara and Sahel Observatory and the African Water Facility.