Unternavigation

Lakes

Nutrient loads in Swiss lakes have been reduced since the 1980s due to intensive efforts to protect bodies of water. Although water quality has improved, several lakes are still over-fertilized. In addition, many ecologically important sections of shore are affected: Control structures reduce the quality of the habitats of plants and animals.

Lake water levels

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

Lake 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. Since 2025, data has been collected at various Swiss lakes for long-term monitoring of water temperature and other parameters, measured continuously at both federal and cantonal levels.

Lake water quality

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.