Das Projekt "Investigations on Storage Processes and on the Residence Time of Runoff Components in the Rietholzbach Basin" wird/wurde gefördert durch: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung. Es wird/wurde ausgeführt durch: Eidgenössische Technische Hochschule Zürich, Geographisches Institut, Abteilung Hydrologie.A detailed hydrograph analysis in the hydrological research basin Rietholzbach provided essential insights into the runoff generating mechanisms in prealpine catchments with a view to the temporal reactions of the hydrological system. The process studies are now further pursued on the basis of field sampling of environmental isotopes (oxygen-18, deuterium, tritium, krypton-85). Automatic samplers allow to obtain time and event dependent water probes which are analysed in the isotopic laboratories of the Geological Institute ETHZ and of the Dept. of Physics, Univ. of Berne. These isotopes serve as tracers to analyse the various runoff processes forming the basin water system in a large range of temporal and spatial scales. The results are an important basis for the regionalisation of subsurface and groundwater flow including dissolved constituents under different climatic and hydrogeologic conditions.