Chloride circulation in a lowland catchment and the formulation of transport by travel time distributions
Chloride circulation in a lowland catchment and the formulation of transport by travel time distributions
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DOI：
10.1002/wrcr.20309
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发表时间：
2013-08-01
影响因子：
5.4
通讯作者：
Botter, Gianluca
中科院分区：
文献类型：
--
作者：
Benettin, Paolo;van der Velde, Ype;Botter, Gianluca
旅行时间是基本的流域描述符，它将有关储存、地球化学、水流路径和水源的关键信息融合到一个连贯的数学框架中。在这里，我们分析了根据荷兰 Hupsel Brook 低地流域的广泛水化学信息估计的旅行时间分布 (TTD)（和相关属性）。这项工作的相关性被认为在于表征非平稳 TTD 以捕获流域传输特性（此处为流域出口处的氯化物通量浓度）的一般重要性。讨论了蒸散量、水储存动力学、水文路径和质量源/汇的相对作用。对不同的水化学模型进行了测试和排名，提供了通过流动和传输过程的耦合校准来改进过程理解的令人信服的例子。该模型再现测量通量浓度的能力主要在于对多个时间尺度 TTD 的非平稳性的描述，包括根区土壤湿度动态和长期季节性动态引起的短期波动。我们的结果证明是可靠的，并且表明，例如，由于系统显示的长记忆力，在一年或多年内大幅减少施肥负荷不会导致胡塞尔径流中平均溶质浓度的显着永久性下降。通过现场和理论证据的比较，我们的结果明确地强调了当前流域内运行的基本运输机制，以期得到普遍应用。
Travel times are fundamental catchment descriptors that blend key information about storage, geochemistry, flow pathways and sources of water into a coherent mathematical framework. Here we analyze travel time distributions (TTDs) (and related attributes) estimated on the basis of the extensive hydrochemical information available for the Hupsel Brook lowland catchment in the Netherlands. The relevance of the work is perceived to lie in the general importance of characterizing nonstationary TTDs to capture catchment transport properties, here chloride flux concentrations at the basin outlet. The relative roles of evapotranspiration, water storage dynamics, hydrologic pathways and mass sources/sinks are discussed. Different hydrochemical models are tested and ranked, providing compelling examples of the improved process understanding achieved through coupled calibration of flow and transport processes. The ability of the model to reproduce measured flux concentrations is shown to lie mostly in the description of nonstationarities of TTDs at multiple time scales, including short-term fluctuations induced by soil moisture dynamics in the root zone and long-term seasonal dynamics. Our results prove reliable and suggest, for instance, that drastically reducing fertilization loads for one or more years would not result in significant permanent decreases in average solute concentrations in the Hupsel runoff because of the long memory shown by the system. Through comparison of field and theoretical evidence, our results highlight, unambiguously, the basic transport mechanisms operating in the catchment at hand, with a view to general applications.