Environmental isotopes were used to determine the source and to understand the physical–chemical processes involved in groundwater movement along a flowpath. This study applies groundwater stable isotopes to assess snow-cover influence on the recharge processes of some regional carbonate aquifers of central Italy. Starting with extensively investigated aquifers, 17 springs were selected and sampled (June–October 2016) for isotope analyses. The δ¹⁸O–δD results follow the local meteoric water line; the low mismatch between the 2016 sampling surveys suggests that those springs are not influenced by seasonal variability. Nevertheless, the average elevations of recharge areas calculated using the vertical isotope gradient were higher compared to those obtained with hypsographic profiles. This means that the relevant contribution to recharge comes from higher elevation areas; hence, snowpack coverage and snowpack persistence over time on recharge areas were analysed using satellite images. Four different relationships between the snowpack characteristics and the elevation of recharge areas have been identified. These offer relevant information about the different degrees of dependence of the regional aquifers of central Italy on the recharge due to high-elevation subbasins where the snowpack cover is significant. A possible correlation emerges between computed isotope recharge elevation and mean snow cover elevation, revealing how snowmelt is a primary source for aquifer recharge. Consequently, to evaluate the risk of groundwater resource depletion in a climate-change scenario, there is discussion on how a potential snow-cover reduction would affect the recharge rate of mountainous aquifers.

环境同位素用于确定来源并了解地下水沿流路运动的物理化学过程。本研究应用地下水稳定同位素来评估积雪对意大利中部一些区域碳酸盐含水层补给过程的影响。从广泛研究的含水层开始，选择并采样了 17 个泉水（2016 年 6 月至 10 月）进行同位素分析。δ ¹⁸O–δD 结果遵循当地的大气水线；2016 年抽样调查之间的低不匹配表明这些泉水不受季节变化的影响。然而，使用垂直同位素梯度计算的补给区平均海拔高于使用海平面剖面获得的平均海拔。这意味着对补给的相关贡献来自高海拔地区；因此，使用卫星图像分析了补给区积雪覆盖率和积雪持续时间。已经确定了积雪特征与补给区海拔之间的四种不同关系。这些提供了有关意大利中部区域含水层对补给的不同程度依赖的相关信息，这是由于积雪覆盖很大的高海拔次流域。计算的同位素补给高程和平均积雪高程之间可能存在相关性，揭示融雪如何成为含水层补给的主要来源。因此，为了评估气候变化情景下地下水资源枯竭的风险，人们讨论了潜在的积雪减少将如何影响山区含水层的补给率。