Classical Karst hydrodynamics: a shared aquifer within Italy and Slovenia.

Classical Karst transboundary aquifer is a limestone plateau of 750 km2 that extends from Brkini hills in Slovenia to Isonzo River in Italy. Since ten years, the Mathematic and Geosciences Department of Trieste University is conducting a monitoring project in order to better understand the groundwater hydrodynamic and the relation between fracture and conduit. 14 water points among caves, springs and piezometers are monitored: hourly temperature, level and EC data are recorded. Two sectors are highlighted: the south-eastern one mainly influenced by the sinking of the Reka River, and a north-western one connected to the influent character of the Isonzo River. Water table fluctuation are significant with risings of more than one hundred meters and during floods the most part of the circuits are under pressure and only a comparative analysis of levels, temperature and conductivity permits a precise evaluation of the water transit times in fractured and/or karstified volumes.