ABSTRACT
By water tracing tests in vadose zone we were searching the connection of defined points at the karst surface with its interior and also the spreading, the velocity of the percolation at given different permeable directions, the intensity and residence time of washing out the induced soluble stuff and the dynamics of rinsing. Cave systems provide an excellent opportunity for intercepting water in vadose zone. Seven water tracings above Planinska, Pivka and Postojnska Jama were carried out. The tracer was injected at the surface, in most cases directly into rocky base and watered; in one case only the tracer was spilt on soil without added water. Sampling points underground were from 40 to 100 m below the surface.
In addition to directions and spreading of water travel we recognized different ways of infiltration through single, variously permeable conduits. In all cases we stated relatively fast water percolation through permeable conduits and rather slower one through wider network of less permeable conduits. How quickly the tracer is washed out of the rocky mass depends mostly on the quantity, distribution and intensity of the rainfall that follows. To determine the returned tracer is made difficult by numerous sampling points where it is difficult to continuously measure a discharge.
