Improving our knowledge of the travel times of water through catchments is critical for the management and protection of water resources and to improve our understanding of fundamental catchment behaviour. In this study we use the age-ranked storage framework StorAge Selection (SAS) to investigate travel times in the Corin catchment, a headwater catchment in the south-east of Australia covered by native Eucalyptus species. Few studies have applied the SAS framework globally and in energy-intensive areas where catchment losses are heavily in favour of evapotranspiration relative to streamflow. A combination of observed and modelled values of oxygen-18 (δ18O), the stable isotope in water, are used to constrain storage selection preferences of streamflow and evapotranspiration and the size of the catchment active storage. The highest performing parameter combinations that could reproduce δ18O in streamflow were dependent on a strong preference for young water in evapotranspiration, and a mixture of weak young and old water preference in streamflow. The mean travel time of streamflow over the study period 2007–2019, weighted by the flow rate, is limited to within a probable range of 2.81–9.77 years. The size of the active storage, a key parameter in the SAS framework, was poorly identified, and in combination with the isotopic inputs into the model, contributed to the uncertainty of the results. We discuss the implications of the results with respect to the study area, as well as within the context of SAS research globally and identify ways to improve the modelling process.

中文翻译：

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使用年龄分级储存和稳定同位素方法限制澳大利亚东南部流域的水龄动态

提高我们对流域水流经时间的了解对于水资源的管理和保护以及提高我们对基本流域行为的理解至关重要。在这项研究中，我们使用按年龄排序的存储框架 StorAge Selection (SAS) 来调查 Corin 流域的旅行时间，Corin 流域是澳大利亚东南部被本地桉树物种覆盖的源头流域。很少有研究在全球和能源密集型地区应用 SAS 框架，在这些地区，流域损失相对于水流而言非常有利于蒸发蒸腾。氧 18 (δ18O)（水中的稳定同位素）的观测值和模拟值的组合用于限制水流和蒸散的存储选择偏好以及集水区主动存储的大小。可以在水流中重现 δ18O 的最高性能参数组合取决于蒸发蒸腾中对年轻水的强烈偏好，以及水流中弱年轻和年老水偏好的混合。2007-2019 年研究期间的径流平均旅行时间，按流速加权，限制在 2.81-9.77 年的可能范围内。活动存储的大小是 SAS 框架中的一个关键参数，但很难确定，并且与模型中的同位素输入相结合，导致了结果的不确定性。我们讨论结果对研究领域的影响，以及在全球 SAS 研究的背景下，并确定改进建模过程的方法。