The Aconcagua river basin (Chile, 32 °S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The δ18O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing “simmr” model revealed that snowmelt input accounted 52% in spring and only 22–36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15–20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14–21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water security in this territory.

中文翻译：

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智利阿空加瓜河从何而来？在冰川和冰缘环境中使用天然示踪剂表征水源

阿空加瓜河流域（智利，32 °S）在过去十年中遭受了特大干旱的影响。严重的降雪量不足极大地改变了流域源头的供水。尽管公认的融雪对盆地有贡献，但冰川、冰缘和地下水输入产生了未知的水流缓冲效应，尤其是在干旱时期。因此，通过结合稳定同位素和离子分析作为天然水示踪剂，对每个季节的每种类型的水源进行了表征和量化。δ18O 和电导率被确定为区分每个水源的关键参数。在稳定同位素混合“simmr”模型中使用这些参数表明，春季融雪输入占 52%，而在一年中其余时间在源头中仅占 22-36%。虽然冰川供应贡献高达 34%，但地下水和冰缘水的贡献率都在 20% 左右，但有一些季节性变化。在下游，冰川贡献平均为 15-20%，地下水季节性增加高达 46%，冰缘输入量惊人地高（即 14-21%）。本工作中报告的阿空加瓜河随时间变化的不同水源贡献量化为该领土的水安全提供了关键信息。冰川贡献平均为 15-20%，地下水季节性增加高达 46%，冰周输入量惊人地高（即 14-21%）。本工作中报告的阿空加瓜河随时间变化的不同水源贡献量化为该领土的水安全提供了关键信息。冰川贡献平均为 15-20%，地下水季节性增加高达 46%，冰周输入量惊人地高（即 14-21%）。本工作中报告的阿空加瓜河随时间变化的不同水源贡献量化为该领土的水安全提供了关键信息。