ABSTRACT
In the first part of the present paper a brief historical review of tracer tests performed in the Joèu karstic system is given. These tests have allowed an accurate delimitation of the Joèu system. The second part is about five quantitative tracer tests carried out in this karstic system between 1991 and 1993. The results demonstrate the existence of a well developed karstic network (structure), and significant differences in the behaviour of the system according to its hydraulic state (time of the hydrological cycle). These differences are observed in hydrodynamics (flow velocities, residence times, …) as well as in hydrogeochemistry (mineralization, CO2-H2O-carbonate system, …).
