State of waterbodies

As Europe’s water tower, Switzerland has substantial water resources. Despite the generally good quality of its water, residues from fertilizer and plant protection products, micropollutants, man-made structures and artificial obstacles damage its surface and underground waters. Analyses and predictions of water levels and flows make it possible to issue early flood warnings.

Swiss water balance

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Water flow & flow regime

In principle, Switzerland has a large water supply that depends on natural factors such as weather conditions or glaciation. However, the volume of water in watercourses is influenced by hydropower production in many areas (residual flow, hydropeaking). In the future, water availability will be limited regionally during dry periods as a result of climate change. The FOEN is monitoring the water flow and flow regime of Swiss bodies of water.


Water temperature is one of the key physical parameters that determines chemical and biological processes in a watercourse. The FOEN’s measurements are the basis for monitoring temperature changes and understanding their causes.

Water quality

Water quality in watercourses has improved significantly since the 1970s in terms of nutrient pollution. Micropollutant contamination is the new and biggest challenge at this time.

Structure and morphology

Swiss watercourses are heavily developed with control structures and their natural functions are limited. Around half of the watercourses located at elevations of up to 600 metres above see level are in poor morphological condition and have many obstacles that impede the migration of fish.

Bed load and suspended solids

Sediment is an important component of ecologically intact rivers and streams. However, the sediment budget is disrupted in around one-third of watercourses. The FOEN monitors the transport of sediment by watercourses across Switzerland.



The FOEN measures the current water levels of Swiss lakes, makes predictions and informs the public.

Water temperature

As a result of climate change, the water temperature of many lakes has risen in recent decades. A further increase is expected. The warming affects the mixing dynamics and thus the oxygen content in the deeper layers of the lakes. In order to monitor the water temperature of selected lakes at national level over the long term, a pilot project is running until 2024.


Since the 1980s, the water quality of Swiss lakes has improved considerably, especially with regard to phosphorus content, which has declined markedly. However, individual lakes are still eutrophic and suffer from oxygen depletion. The concentrations of micropollutants in Switzerland's large lakes are generally below the limit values. The quality of water in lakes used for bathing is generally good. But plant and animal life in Swiss lakes is strongly impacted by human activity.


Groundwater resources

Switzerland is rich in groundwater. Groundwater resources occur almost everywhere, both in unconsolidated sediments and fissured or karstified bedrock. They represent an important natural and economic resource.

Groundwater quantity

The quantity of groundwater in Switzerland fluctuates during the year, but is stable in the long term.

Groundwater quality

Groundwater does not naturally contain any persistent synthetic substances. Nitrate and residues of plant protection products have a long-lasting adverse impact on groundwater quality. Along watercourses, micropollutants from industry, commerce and households are also found in groundwater.

Groundwater temperature

To date, there has been no observable overall increase in groundwater temperature across Switzerland. In certain regions of the country, however, a slight rise in groundwater temperatures indicates the impact of climate change. For example, groundwater temperatures are rising by up to 0.06 °C per year in the Alpine region, in unconsolidated rock outside valley floors in the Central Plateau, and in the Jura. Direct human impacts on groundwater are also leading to measurable changes in groundwater temperature in densely populated areas.

Stable water isotopes

The stable water isotopes deuterium and oxygen-18 are natural tracers in the water cycle that can be used to determine the origin of water components and to track climatic changes.

NAQUA National Groundwater Monitoring

The NAQUA National Groundwater Monitoring provides a nationally representative picture of the situation and development of the groundwater resources in terms of both quality and quantity.


Quality of the forecasts

The water level and discharge forecasts are based on hydrological and meteorological data and the hydrological model WaSiM. The quality of the hydrological forecasts is affected by various factors such as the size of the catchment and its hydrological complexity, and by the weather conditions.

Further information

Last modification 23.08.2022

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