Groundwater

The great unknown

Although at least 80% of drinking water comes from groundwater (see Water Use and Consumption), the renewal of this resource is not well understood. An unknown portion of the effluent from the water balance feeds the groundwater, while the same amount of groundwater feeds back into watercourses (the total water balance doesn’t change). It is assumed (Sinreich et al. 2012) that only about 10% of the theoretically usable groundwater in Swiss reservoirs can be sustainably replaced (equivalent to about a third of the annual rainfall, or 18 km3). The natural replacement of the groundwater depends on the aquifer type (see Glossary). Water can linger for a long time in different aquifers. This time is determined by the underlying geology (how well can the (rain)water seep into the aquifer?), by the size of the groundwater resources, and by the presence of watercourses. The residence time of groundwater can be between a few months (along rivers such as the Aare) to over 10 years (limestone areas like those found in parts of the Alps and Jura mountains). In the case of heavy precipitation in karst areas, the rivers react quickly, although the majority of the water flows away underground before emerging at a source. Thus, all groundwater is not well mixed. Imagine a wet sponge: if more water is introduced, some of the water already in the sponge is pressed out.

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Beurteilung von belasteten Standorten über Karstgrundwasser
  • 2018

Beurteilung von belasteten Standorten über Karstgrundwasser

Diese Publikation beschreibt ein Verfahren zur Untersuchung und Beurteilung des Überwachungs- und Sanierungsbedarfs von belasteten Standorten in Karstgebieten hinsichtlich des Schutzguts Grundwasser. Das Verfahren stützt sich auf die Altlasten-Verordnung (AltlV) und auf das Schadstoffpotential, das Emissionsverhalten am Standort sowie die Untersuchung der Karstquellen im Abstrombereich des Standorts.
Hydrological Yearbook of Switzerland 2017
  • 2018

Hydrological Yearbook of Switzerland 2017

Summary of the publication “Hydrologisches Jahrbuch der Schweiz 2017”.