This meeting organized by the Africa division of the AIEA with participation of experts from the three countries sharing the North Western Sahara aquifer system (Algeria, Tunisia and Libya) focuses on the study of the specificities of the

NWAS. Its main objectives are:

• To consider the progress of the isotopic activities
• To analyze the first results obtained
• To draw a complementary program for the next step (2004-2005)

OSS is associated to the animation of this workshop with its experience with the objective of accompanying the works of the countries within the framework of the second step of the NWSAS aimed to deepen the knowledge about the hydrodynamic and geochemical functioning of the aquifer