More water in spring, less in summer. Climate change affects not only the amount of water, but also when it is available.
A new study led by Martin Masten from the University of Graz, with the participation of Assoc. Prof. Dr. rer. nat. Matevž Vremec from Alma Mater Europaea University and other research colleagues from Graz, examines the impact of climate change on alpine springs. The study Climate change impacts on alpine springs in Austria: shifts in discharge seasonality and water availability was published in the scientific journal Journal of Hydrology.
The researchers studied 70 alpine springs in the Austrian Alps region, which differ from one another in their climatic and hydrogeological characteristics. Using precipitation-runoff models that also account for snow, they analyzed how spring discharge could change under three different greenhouse gas emission scenarios up to the year 2100. They compared the historical period 1980–2009 with the near future 2030–2059 and the period 2070–2099.
The results paint an interesting picture. The biggest changes are not necessarily expected in the total annual amount of water, but rather in its distribution throughout the year. Changes in annual discharge for most analyzed groups remain within a range of a few percent in either a positive or negative direction, while seasonal shifts are considerably more pronounced.
For springs that are strongly dependent on snow, the researchers predict an increase in discharge in spring, while discharge decreases in summer and autumn. Less water in the summer period is also expected for springs that respond quickly to precipitation and other hydrological changes.
The timing of the lowest discharges is also changing significantly. Periods with the least water, which previously occurred mainly in late winter and early spring, are projected to shift toward summer and autumn. Under scenarios with higher greenhouse gas emissions, this shift is even more pronounced.
This means that some alpine springs could be most vulnerable in the future דווקא during summer droughts. As Vremec emphasized when presenting the research: due to earlier snowmelt, we can expect more water in spring and less in summer.
Differences are also evident between individual parts of Austria. The study predicts a decrease in spring discharge in western Austria under all considered scenarios and time periods, while under the medium and high emission scenarios, decreases also occur in the south of the country. Among the most sensitive are springs whose recharge is connected to snow, as well as springs with a marked decline in discharge after the recharge period.
The findings are also important from the perspective of drinking water supply. Spring water provides approximately half of Austria’s drinking water needs, and in some regions it is even the only source of supply. Understanding future changes is therefore important not only for researching the impacts of climate change, but also for planning adaptation and the sustainable management of water resources.
