ABSTRACT
The Reka-Timavo underground karst system is one of the main karst phenomena of Mediterranean region which roused the interest of scientist from the second century AD up to present. The Reka-Timavo underground stream develops in a NE direction for at least 40 km (as the crow flies), according to a hipsographic curve which shows more than 5% slope during the first 4 km. The data initially collected confirm the importance of continuous measurement in karst waters study. The Timavo hypogean river indeed is a very complex aquifer with unpredictable behavior: our work illustrate first results and preliminary comments. The Reka river average discharge has been almost 15 cu.m/s; maximum discharge has been 113 cu.m/s recorded in march, 3rd. Conductivity decrease characterizes floods, but the river’s regimen depends from the ratio between meteoric waters percolating in the hypogean aquifer and Reka River waters swallowed near Skocjan (they have low values of solute, but high values in suspended matters).
