Groundwater levels and spring discharge rates
The indicator provides a nationwide year-on-year overview of the frequency of the occurrence of low, normal and high groundwater conditions. If groundwater levels fall below average as a result of severe drought, this can lead to shortages in the water supply and negatively impact groundwater-dependent ecosystems. If groundwater levels rise significantly as a result of above-average rainfall, this can lead to considerable damage to land and buildings. In addition, near-surface landslides and debris flows may be triggered on slopes.
impossible to evaluate
impossible to evaluate
In the dry years of 2003, 2011, 2018/2019, 2022 and 2023, an exceptionally high number of monitoring sites recorded low groundwater conditions.
In 2001–2002, 2006/2007, 2016 and 2021, on the other hand, around one in four monitoring sites recorded an above-average number of days with high groundwater levels and spring discharges. During the floods of 2021, an unusually high number of monitoring stations with high groundwater conditions were recorded.
According to the CH2018 climate scenarios, the frequency and duration of droughts and the intensity and volume of precipitation are expected to increase in the long term. This would mean that low and high groundwater levels and spring discharges, as defined by the indicator, could occur more frequently. There is currently no discernible long-term trend in either low or high groundwater levels and spring discharges. Years with low or high levels of groundwater and spring discharges alternate regularly. For this reason, the indicator is not evaluated.
- Related indicators
- Flood events
There is currently no standardised indicator in international indicator systems such as the EEA. IGRAC, the International Groundwater Resources Assessment Centre, and individual countries such as Belgium, France and Austria use similar approaches.
Groundwater levels and spring discharges are continuously recorded at the QUANT module monitoring sites (around 50 FOEN monitoring sites and 50 cantonal monitoring sites) in the NAQUA National Groundwater Monitoring Programme. The indicator is based on a calculation of the annual number of monitoring sites with an above-average number of days with low, normal and high groundwater levels and spring discharges. For this purpose, the daily mean values are determined at individual monitoring sites and compared with the corresponding 10th or 90th percentile of the standard period 2001–2020. Groundwater conditions at the monitoring site are classified as 'low' if the number of days with groundwater levels and spring discharges below the 10th percentile of the 2001–2020 standard period is greater than the average of the number of days from the standard period. Groundwater conditions at the monitoring site are classified as 'high' if the number of days with groundwater levels and spring discharges below the 90th percentile of the 2001–2020 standard period is greater than the average of the number of days from the standard period. Normal groundwater conditions are defined as those where the number of days below the 10th percentile or the number of days above the 90th percentile is less than the respective average of the number of days from the 2001-2020 standard period, or where the daily averages are between the 10th and 90th percentiles.
The indicator describes the percentage of monitoring sites with low, normal and high groundwater conditions in the respective year.
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