High-Resolution Karst Spring Discharge Datasets of the Euro-Mediterranean Mountain Regions

Abstract. Karst groundwater systems exhibit heterogeneity in recharge, circulation, and discharge, occupying a unique position within groundwater systems. This complexity facilitates rapid responses via the preferential flow routes, making karst systems vulnerable to climatic and anthropogenic pressures. High-altitude karst aquifers are particularly susceptible to shifting climate patterns – specifically rising temperatures, declining snow cover, and increasingly less and inconsistent precipitation – within the Mediterranean climate hotspot. Effective sustainable management of these groundwater systems require robust hydrological modelling; however, the application of such models is often constrained by the availability of high-quality, reliable datasets. This study presents a comprehensive collection of high-resolution karst spring discharge data from major Euro-Mediterranean mountain belts, including the Atlas, Betics, Pyrenees, Jura, Alps, Carpathians, Apennines, Dinarides, Hellenides, Balkans, Taurus, Levant, and Zagros. We compiled a total of 118 discharge time series specifically curated for hydrological modelling. Geographically, the dataset is led by the Alps (approx. 42%), followed by the Dinarides (approx. 10%), with the Apennines, Carpathians, and Zagros each contributing approx. 7%. The Levant and Taurus account for approx. 5% each, while the remaining regions (Atlas, Balkans, Betics, Hellenides, Jura, and Pyrenees) represent less than 5% each. In terms of temporal resolution, 92% of the records are daily, while hourly and monthly data each comprise 4%. The average record length is 19 years, which is led by a 99-year series from Unica Spring, Slovenia (1926–2025). Regional analysis indicates that the Alps, Apennines, Balkans, Betics, Dinarides, Jura, and Levant maintain average record lengths exceeding 20 years, whereas the Atlas, Carpathians, Taurus, and Zagros range between 10 and 20 years. The shortest average records were observed in the Hellenides and Pyrenees (7 and 8 years, respectively), which is still adequate for hydrological modelling applications.