Analysis of groundwater levels in various hydrogeological environments in Sweden

Recording and analysing groundwater level data can reveal the nature and extension of groundwater processes like flow direction and recharge magnitude. The analyses can even indicate the influence of precipitation, evapotranspiration and runoff on the subsurface processes. However, such analyses are only possible when the recorded data cover relatively large periods of time at a suitable frequency.

This work presents a time series analysis of groundwater levels in wells located in typical hydrogeological settings in Sweden. The aim was to identify eventual trends in the natural variations of groundwater levels in relatively deep aquifers. The analysis included identifying possible correlations between groundwater levels, precipitation and evapotranspiration. Additionally, the intention was to evaluate the possible relationships between groundwater levels in deeper aquifers and level variations in surficial glacial deposits. The work addresses also the characteristics of the hydrogeological environments where the observation wells are located. The data was retrieved from twenty wells selected from a database available at the Geological Survey of Sweden (SGU). The results indicate varying correlations between groundwater levels, precipitation and evapotranspiration. This is probably explained by the different hydrogeological environments where the observation wells are located and the respective aquifers’ degree of confinement.