The impact of snow cover and precipitation phase on groundwater recharge

Catchment storage affects the runoff response to snowmelt or rainfall events. Although changes in snow cover will affect streamflow responses, there is currently a lack of knowledge of how changes in snow cover will affect groundwater storage. This is important as summer low flows are often sensitive to changes in groundwater storage. This study aims to investigate how groundwater level fluctuations differ during rainfall versus snowmelt events and if the effect of the precipitation phase on groundwater recharge and storage varies across a catchment.

This study uses data from high-frequency measurements from 44 wells from the 20-ha Studibach catchment in the pre-alps in Switzerland (2010-2024 data), 48 wells from the C6 and C2 catchments in the Krycklan catchment in Sweden (2018-2024 data), and five wells from the Rokytka catchment in the Vydra catchment in Czech Republic (2013-2023 data). It analyses the response of the groundwater during periods with snow cover (rain-on-snow events), during snowmelt events, and rainfall events and whether these differences depend on the location of the catchment (as represented by, for example, the topographic wetness index, slope, and land cover). Furthermore, it determines the correlation between the site characteristics and how this differs for these three types of events. These results will be helpful to understand better how changes in snow due to cover climate change will affect groundwater recharge and storage, and thus streamflow.