Project description

The striking summit of the Sulzfluh lies at the border between Vorarlberg and Graubünden and is composed of the very pure and therefore extremely karstifiable Sulzfluh limestone from the Upper Jurassic. To the east, the Penninic Sulzfluh nappe dips under the Eastern Alpine Silvretta nappe, which consists of dark crystalline rocks. At the bottom, the Sulzfluh limestone is sealed by the impermeable Prättigau Flysch. This unique tectonic setting results in long-distance karst groundwater flow beneath the crystalline cover. Finally, in the tectonic window of Gargellen to the east, where the limestone is exposed again, the water emerges at numerous springs. This provides a unique opportunity to study the hydrogeology of a karst aquifer under crystalline cover.

Targeted hydrochemical analyses of the water at the springs and on the karst plateau of the Sulzfluh before it enters the subsurface in large swallow holes and fissures will be used to investigate the influence of the overlying crystalline rock on the karst aquifer in more detail. Of particular interest is the change in water chemistry from infiltration to emergence at the springs. The aim is to show whether certain infiltration areas on the karst plateau are hydrochemically connected to specific springs and thus draw possible conclusions about the origin, flow path and velocity of the water. Tracer tests with artificial fluorescent dyes will help to validate the findings and further quantify the hydrodynamic conditions of the system. The project can provide important new information about an area that has been only little studied from a hydrogeological point of view. The gained knowledge can be particularly helpful in terms of groundwater protection and the vulnerability of the aquifer, especially for the local people who partially use the spring water directly as drinking water.