Isotope study in the alpine karst region of Rawil (Switzerland)

An isotope study in the karst of the high Alps in Switzerland is described. From 1973 to 1978 the discharge, 3H, delta18O, conductivity and temperature were measured in representative springs, which are influenced by snow melt in late spring and summer, by rain in late summer and autumn, and in the winter period, when infiltration stops, by reservoir water. Since tritium in precipitation during recent years was scattered irregularly in time and space, the residence time of winter base flow (2-4 years) could not be determined very precisely. The pronounced difference in delta18O between several springs allowed the difference in mean altitude of their recharge areas to be estimated.