Groundwater levels and spring discharges

While groundwater levels and spring discharges in Switzerland are stable in the long term, they fluctuate throughout the year on account of the cumulative amount of precipitation in the preceding months. Groundwater quantity usually varies across regions from year to year, and changes in levels are subject to a certain time delay depending on weather conditions.

Infiltration from river water is primarily responsible for groundwater levels in the unconsolidated aquifer reservoirs in the broad flood plains of the rivers Rhone, Aare, Ticino, Reuss, Limmat, Thur and Rhine. In the unconsolidated and consolidated rock in other regions, groundwater is formed predominantly from melt water or rainwater runoff, depending on the elevation. During dry periods, groundwater widely feeds the smaller rivers of the Swiss Plateau. The variable recharge conditions and the interrelationship between surface water and groundwater cause typical seasonal fluctuations in groundwater levels and spring discharges. Groundwater use, land use, soil improvement, construction and climate change can all have an impact on the status and trend of groundwater levels and spring discharges.

Groundwater levels reflect the weather conditions

Groundwater levels and spring discharges across the country are continually recorded at around 100 NAQUA National Groundwater Monitoring sites. The levels reflect the weather conditions on the surface, though in attenuated form and subject to a time delay. Long periods of precipitation – especially in winter – increase groundwater recharge. In contrast, sustained periods of drought – particularly in summer and autumn – can result in low groundwater levels and spring discharge, thus affecting the groundwater quantity.

Long-term trend is stable

Long-term weather patterns (temperature and precipitation) in Switzerland are often correlated with periodic fluctuations in groundwater levels lasting for several years, entailing a regular succession of low and high water situations. Within this general pattern, significant regional differences are the norm.

In recent times, the dry years of 2011, 2015, 2018, 2019 and 2020 in particular led to low groundwater levels and spring discharges. In contrast, years with above-average amounts of precipitation (e.g. 1999–2002, 2021) resulted in generally high groundwater levels and spring discharges.

The difference in high and low water situations varies depending on the particular features of the aquifer. For example, groundwater resources connected to watercourses react quickly to heavy precipitation, whereas deeper groundwater resources often do not react to individual rainfall and only show a slight change in level after a few months of prolonged rainfall or drought.

High 2021: 35 Normal 2021: 50 Low 2021: 15 High 2020: 21 Normal 2020: 53 Low 2020: 26 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

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Last modification 17.05.2022

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