The hillslope rainfall-outflow interactions, groundwater fluxes were examined in the headwater catchment Uhlířská, Czech Republic. A quick communication of the vadose zone with the granitic bedrock via preferential subsurface flowpaths is assumed, in agreement with the observation of storm-caused instant water transformation to outflow through the permeable Cambisol. A quick response of a high magnitude outflow occurs regularly, although the surface runoff is very rare. Standard climatic and hydrological monitoring in the Uhlířská catchment is supplemented by the measurements of processes in the vadose zone and natural tracing of isotope 18O and 2H and SiO2 content in water. Up to 75% of the event catchment runoff was assigned to pre-event water, of which about 50% had been stored in the shallow soil subsurface on the hillslopes. The hillslope soil layers control the distribution of the flow into the groundwater and/or the shallow subsurface flow during the rainfall-runoff episode.
