Indicator water

Groundwater levels and spring discharge rates

The indicator provides a national overview of the frequency of low, normal and high groundwater conditions year on year. If the groundwater level falls more than average due to prolonged dry periods, this can cause bottlenecks in the water supply and be detrimental to ecosystems reliant on groundwater. If the groundwater level becomes extremely high due to above-average precipitation, substantial damage can be caused to landscapes and buildings. Moreover, this can trigger near-surface landslips and mudslides.

Assessment of the state
impossible to evaluate impossible to evaluate
Assessment of the trend
impossible to evaluate impossible to evaluate
High 2019: 17 Normal 2019: 51 Low 2019: 32 High 2018: 17 Normal 2018: 51 Low 2018: 32 High 2017: 7 Normal 2017: 63 Low 2017: 30 High 2016: 25 Normal 2016: 59 Low 2016: 16 High 2015: 12 Normal 2015: 72 Low 2015: 16 High 2014: 20 Normal 2014: 75 Low 2014: 5 High 2013: 21 Normal 2013: 75 Low 2013: 4 High 2012: 16 Normal 2012: 72 Low 2012: 12 High 2011: 4 Normal 2011: 63 Low 2011: 33 High 2010: 14 Normal 2010: 59 Low 2010: 27 High 2009: 13 Normal 2009: 67 Low 2009: 20 High 2008: 19 Normal 2008: 69 Low 2008: 12 High 2007: 24 Normal 2007: 62 Low 2007: 14 High 2006: 23 Normal 2006: 50 Low 2006: 27 High 2005: 9 Normal 2005: 43 Low 2005: 48 High 2004: 9 Normal 2004: 66 Low 2004: 25 High 2003: 15 Normal 2003: 49 Low 2003: 36 High 2002: 30 Normal 2002: 60 Low 2002: 10 High 2001: 48 Normal 2001: 48 Low 2001: 4 High 2000: 29 Normal 2000: 62 Low 2000: 9 High 1999: 41 Normal 1999: 47 Low 1999: 12 High 1998: 9 Normal 1998: 47 Low 1998: 44 High 1997: 8 Normal 1997: 61 Low 1997: 31 High 1996: 10 Normal 1996: 63 Low 1996: 27 High 1995: 37 Normal 1995: 48 Low 1995: 15
Percentage of monitoring stations at which low, normal and high groundwater levels and/or spring discharge rates were recorded in each year.

Data for the graph: Excel
Source: Federal Office for the Environment
Comment

In 1997/1998, 2003, 2005, 2011 and 2017-2019, approximately one in three monitoring stations recorded above-average days with low groundwater levels and/or spring discharge rates. The dry years of 2003, 2011 and 2018/2019 resulted in an unusually high number of monitoring stations with low groundwater conditions.

Conversely, in 1995, 1999–2002, 2006/2007, 2012/2013 and 2016, approximately one in four monitoring stations recorded above-average days with high groundwater levels and/or spring discharge rates. The floods of 1995 and 1999 and the prolonged precipitation surplus from 2000 to 2002 resulted in a larger number of monitoring stations with high groundwater conditions in these years.

Based on the CH2018 climate scenarios, it must be assumed that the frequency and duration of dry periods as well as precipitation intensity and strength will tend to increase over the long term and therefore that low and high groundwater levels and spring discharge rates as defined in the indicator may occur more frequently. A long-term trend cannot yet be detected for either lower or high groundwater levels and spring discharge rates. Years with high and low groundwater levels and spring discharge rates succeed each other regularly. For this reason the indicator is not evaluated.

International comparison

At present there is no standardised indicator in international indicator systems such as the EEA. Similar approaches are now being pursued in various countries (e.g. Belgium, Austria).

Method

Groundwater levels and spring discharge rates are continuously recorded at the monitoring stations in the National Groundwater Monitoring NAQUA, QUANT module (some 50 FOEN monitoring stations and 50 cantonal stations). The indicator includes calculation of the annual number of monitoring stations with an above-average number of days with low, normal and high groundwater levels and spring discharge rates. The daily averages are determined at each individual monitoring station and compared with the corresponding 10th and 90th percentiles over 20 years of monitoring. If the number of days on which the groundwater level and spring discharge rate are below the 10th percentile from the 20-year period exceeds the average number of days over the 20-year period, the groundwater conditions at the monitoring station are described as ‘low’. If the number of days on which the groundwater level and spring discharge rate are above the 90th percentile from the 20-year period exceeds the average number of days over the 20-year period, the groundwater conditions at the monitoring station are described as ‘high’. Normal groundwater conditions exist if the number of days below the 10th percentile and/or the number of days above the 90th percentile are below the respective average number of days over the 20-year monitoring period, and/or the daily averages are between the 10th and 90th percentile.

The indicator defines the percentage of these monitoring stations with low, normal and high groundwater conditions in the relevant year.

 
Last updated on: 28.07.2020

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