Current understanding of groundwater recharge and groundwater drought in Sweden compared to countries with similar geology and climate

ABSTRACT Recently, groundwater in Sweden has attracted media attention due to supply shortages caused by dry periods and low groundwater levels. About half of Swedish drinking water stems from groundwater. The small Swedish aquifers are highly dependent on frequent and sufficient recharge. Groundwater recharge forms the link between meteorological and groundwater drought and thus the main link between climate change and sustainable water supply. This study evaluated whether the current knowledge on groundwater recharge and groundwater drought is sufficient to mitigate the impacts of climate change. A review of international literature on groundwater recharge in regions with conditions similar to Sweden was performed. National literature was compared and links to international studies evaluated. A survey among Swedish groundwater experts complemented the study. Findings are that research on groundwater recharge has been scarce in Sweden over the last decades and Swedish experts seem to not have taken much notice of international literature. It is concluded that Sweden is not well prepared to predict the impact of climate change on groundwater resources, as the most crucial process linking climate to groundwater is not well understood. The study has a strong focus on Sweden, however, the results are also relevant for countries with similar geology and climate. One main conclusion is that groundwater recharge studies often remain unique, and thus hardly transferable and comparable. Two or more independent studies are rarely applied in parallel, verification based on direct groundwater observations is not common. This raises concerns about the reliability of climate change impact predictions on groundwater.