ISOT module

The ISOT module of the NAQUA National Groundwater Monitoring records changes over time in stable water isotopes oxygen-18 and deuterium in watercourses and precipitation at selected monitoring sites.

ISOT provides reference data for local hydrogeological studies, such as on the origin and age of groundwater, and shows the long-term impacts of climate change on the isotopic signature in precipitation, watercourses and groundwater. For that purpose, stable water isotopes oxygen-18 and deuterium are analysed at a total of 22 precipitation and watercourse monitoring sites.

The 13 precipitation monitoring sites are distributed across the different climatic regions of Switzerland (Jura, Plateau, Alps). They also cover the elevations along a NW/SE profile from Berne (541 m a.s.l.) over the Grimsel Pass (1950 m a.s.l.) to Locarno (379 m a.s.l.). The monitoring sites are situated close to the MeteoSwiss meteorological monitoring sites where other parameters such as air temperature and vapour pressure are collected.

The nine watercourse monitoring sites are mostly situated at the main inlets to the large lakes. The monitoring site of the River Rhine at Diepoldsau and at Weil, the Rhone at Porte du Scex and at Chancy, the Ticino at Riazzino, the Inn at S-chanf and the Aare at Brugg are shared by the National River Monitoring and Survey Programme NADUF.