Temporal dynamics in dominant runoff sources and flow paths in the Andean Páramo
Temporal dynamics in dominant runoff sources and flow paths in the Andean Páramo
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DOI：
10.1002/2016wr020187
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发表时间：
2017-07
影响因子：
5.4
通讯作者：
Alicia Correa;D. Windhorst;D. Tetzlaff;P. Crespo;R. Célleri;J. Feyen;L. Breuer
中科院分区：
文献类型：
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作者：
Alicia Correa;D. Windhorst;D. Tetzlaff;P. Crespo;R. Célleri;J. Feyen;L. Breuer
集水区的水源来源和水流路径的相对重要性在空间和时间上各不相同，这使得降雨-径流响应的概念化变得复杂。我们通过端元混合分析(EMMA)、线分离和反渡越时间代理(ITTP)估计厄瓜多尔安第斯山脉的源头流域，评估了源区、径流路径和年龄的时间动态。分析了一条溪流和12个潜在来源的22种溶质、稳定同位素、pH和电导率。需要四个终端成员令人满意地代表水文系统，即降雨、泉水和来自组织土壤和安多索尔底层的水。来自河岸带及其附近的组织土壤的水是全年径流的最大来源贡献者(旱季为39%，雨季为45%)，突显了储存在河岸带的水的重要性。在较为干旱的季节，泉水对径流的贡献增加了两倍，这一点得到了与较深流动路径一致的地球化学特征的证明，而不是通过安多索尔的浅层相互流动。降水在这一贡献中表现出较低的季节变化。过程线分离显示，在较干燥和较潮湿的季节，分别有94%和84%的水是事件前的水。从枯水到丰水，除泉水外，所有来源的贡献率都有所增加。当河岸带的贡献面积扩大时，河水的相对年龄在较潮湿的时期减少。多方法和多示踪方法使人们能够从年际的角度密切研究水流过程和水源动态相互作用的重要性。
The relative importance of catchment's water provenance and flow paths varies in space and time, complicating the conceptualization of the rainfall‐runoff responses. We assessed the temporal dynamics in source areas, flow paths, and age by End Member Mixing Analysis (EMMA), hydrograph separation, and Inverse Transit Time Proxies (ITTPs) estimation within a headwater catchment in the Ecuadorian Andes. Twenty‐two solutes, stable isotopes, pH, and electrical conductivity from a stream and 12 potential sources were analyzed. Four end‐members were required to satisfactorily represent the hydrological system, i.e., rainfall, spring water, and water from the bottom layers of Histosols and Andosols. Water from Histosols in and near the riparian zone was the highest source contributor to runoff throughout the year (39% for the drier season, 45% for the wetter season), highlighting the importance of the water that is stored in the riparian zone. Spring water contributions to streamflow tripled during the drier season, as evidenced by geochemical signatures that are consistent with deeper flow paths rather than shallow interflow through Andosols. Rainfall exhibited low seasonal variation in this contribution. Hydrograph separation revealed that 94% and 84% is preevent water in the drier and wetter seasons, respectively. From low‐flow to high‐flow conditions, all the sources increased their contribution except spring water. The relative age of stream water decreased during wetter periods, when the contributing area of the riparian zone expands. The multimethod and multitracer approach enabled to closely study the interchanging importance of flow processes and water source dynamics from an interannual perspective.