Climate change impacts on alpine springs in Austria: shifts in discharge seasonality and water availability

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Spring water supplies about half of Austria’s drinking water demand and is the sole source in some regions. Climate change is rapidly altering hydrological conditions in the Alps, making projections of future spring discharge essential for sustainable water management. This study assesses climate change impacts on 70 alpine springs across the Austrian Alps, covering a wide range of climatic and hydrogeological settings. Plausible catchments were identified using a rainfall–runoff model with a snow module, which was forced with climate projections from three emission scenarios (RCP 2.6, 4.5, and 8.5) and 40 model realizations to evaluate impacts until 2100. Changes were assessed by comparing a historical reference period (1980–2009) with a near-future period (2030–2059) and a far-future period (2070–2099). Analyses were conducted for individual springs and hydrologically classified spring groups. Results indicate decreasing spring discharge in western Austria under all scenarios and periods. Under RCP 4.5 and 8.5, discharge reductions also emerge in southern Austria. Annual discharge changes generally remain within single-digit percentages, in both positive and negative directions, but differ among spring groups. Snow-dominated and recession-dominated springs show the highest sensitivity to emission scenarios, whereas fast-responding springs maintain positive annual changes. Seasonal shifts are pronounced, with increased spring time discharge for snow-dominated springs and reduced summer and autumn discharge for both snow-dominated and fast-responding springs. Low flows shift from late winter and early spring toward summer and autumn, intensifying under higher-emission scenarios. These results provide a basis for climate adaptation and sustainable water management in Austria.