Estimation Of Groundwater Residence Times By A Multi-tracer Approach In A High Alpine Catchment Area, Switzerland

HR: 0800h
AN: H11C-0663 [Abstracts]
TI: Estimation Of Groundwater Residence Times By A Multi-tracer Approach In A High Alpine Catchment Area, Switzerland
AU: * Haemmig, C
EM: chris_haemmig@geoenv.k.u-tokyo.ac.jp
AF: University of Tokyo, School of Frontier Science, Department of Environment Systems, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8561, Japan
AU: Tokunaga, T
AF: University of Tokyo, School of Frontier Science, Department of Environment Systems, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8561, Japan
AU: Asai, K
AF: Geo-Science Laboratory, 1-608 Ueda Honmachi Tenpaku, Nagoya, 4680007, Japan
AU: Asai, K
AF: Geo-Science Laboratory, 1-608 Ueda Honmachi Tenpaku, Nagoya, 4680007, Japan
AU: Hayashi, T
AF: Akita University, Faculty of Education and Human Studies, Tegata-gauenmachi 1-1, Akita city, Akita, 010-8502, Japan
AB: The groundwater flow paths and residence times are investigated to establish a model for a high alpine catchment area in the Swiss Alps. The study area is located in the periglacial zone with mean surface temperatures around 0° C. All springs in the study area have been mapped cartographically and several natural springs were examined in detail on physiochemical parameters. However, the major element composition alone could not give satisfying information to understand the hydrogeological setting in the catchement area. Therefore, a multi-tracer approach using chlorofluorocarbons (CFCs), sulfur hexafluoride (SF₆) and tritium/helium (³H/³He) is taken to obtain further details on groundwater behaviour. CFCs (CFC-11, CFC-12 and CFC-113) concentrations showed a similar residence time for all but two sampled springs when we applied a piston-flow model to calculate residence times. Consistent results were obtained from CFC-12/CFC-113 ratios, supporting the applicability of a simple piston-flow model for the study area. Two springs contained much smaller CFCs concentrations compared to the other ten measured springs, indicating the existence of groundwater with longer residence times. These springs also showed high sulphate and calcium concentrations. Together with ³H/³He and SF₆, the CFC based residence time can be calibrated. This multi-tracer approach allows a better understanding of groundwater behaviour and infiltration processes in a high alpine area.
DE: 1806 Chemistry of fresh water
SC: Hydrology [H]
MN: 2007 Fall Meeting