Surface and subsurface water contributions to streamflow from a mesoscale watershed in complex mountain terrain
Surface and subsurface water contributions to streamflow from a mesoscale watershed in complex mountain terrain
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DOI：
10.1002/hyp.11469
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发表时间：
2018-03
影响因子：
3.2
通讯作者：
Qinghuan Zhang;J. Knowles;R. Barnes;R. Cowie;N. Rock;M. Williams
中科院分区：
文献类型：
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作者：
Qinghuan Zhang;J. Knowles;R. Barnes;R. Cowie;N. Rock;M. Williams
了解地表水和地下水对河流流量的贡献对于准确预测经常作为下游社区水塔的山区流域的供水至关重要。因此，本研究使用末端成员混合分析技术来调查264平方公里博尔德河流域的水源贡献和水文流动路径，该流域流经美国科罗拉多前山脉。使用了四种保守的水化学示踪剂来描述该流域为一个3端元系统，示踪剂浓度重建表明，端元混合分析的应用是稳健的。2009 - 2011年，亚高山地区融雪量、雨水和高山地区地下水对年流量的贡献分别为54%、22%和24%。这些值表明，相对于以前在源头尺度上得出的面积加权平均值，雨水对径流的贡献增加了，雪水对径流的贡献减少了。幼水（2.3±0.8个月）从高山流域的18-22%下降到低海拔流域和流域出水口的8-10%，这对地下蓄水和水文连通性有影响。这些结果有助于基于过程的对中尺度流域季节源水组成的理解，可用于在更大的空间尺度上推断源水流产生的预测。
An understanding of surface and subsurface water contributions to streamflow is essential for accurate predictions of water supply from mountain watersheds that often serve as water towers for downstream communities. As such, this study used the end‐member mixing analysis technique to investigate source water contributions and hydrologic flow paths of the 264 km2 Boulder Creek Watershed, which drains the Colorado Front Range, USA. Four conservative hydrochemical tracers were used to describe this watershed as a 3 end‐member system, and tracer concentration reconstruction suggested that the application of end‐member mixing analysis was robust. On average from 2009 to 2011, snowmelt and rainwater from the subalpine zone and groundwater sampled from the upper montane zone contributed 54%, 22%, and 24% of the annual streamflow, respectively. These values demonstrate increased rainwater and decreased snow water contributions to streamflow relative to area‐weighted mean values derived from previous work at the headwater scale. Young water (2.3 ± 0.8 months) fractions of streamflow decreased from 18–22% in the alpine catchment to 8–10% in the lower elevation catchments and the watershed outlet with implications for subsurface storage and hydrological connectivity. These results contribute to a process‐based understanding of the seasonal source water composition of a mesoscale watershed that can be used to extrapolate headwater streamflow generation predictions to larger spatial scales.