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首页> 外文期刊>Hydrological Processes >Suspended sediment dynamics associated with snowmelt runoff in a small mountain stream of Lake Tahoe (Nevada)
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Suspended sediment dynamics associated with snowmelt runoff in a small mountain stream of Lake Tahoe (Nevada)

机译：太浩湖（内华达州）的一条小溪流中与融雪径流有关的悬浮泥沙动力学

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The Lake Tahoe basin is experiencing an environmental decline that is partly due to sediment intakes from its tributaries. Many studies have estimated suspended sediment loads in these streams with a discrete sampling programme by collecting water samples and using a rating technique. However, the relationship between stream discharge and suspended sediment concentration (SSC) in these tributaries is known to differ during the rising and falling limbs of the snowmelt-dominated hydrograph. Because of this hysteresis effect, sediment rating curves are poor predictors of suspended sediment dynamics in the stream. In this study, suspended sediment transport was investigated using a turbidity meter to provide a continuous record of sediment concentration during the snowmelt period. Hysteresis in suspended sediment transport was also investigated and is quantified with an H index, which is the ratio of the areas under the curve at different stages of the hydrograph. The temporal lag between the peak of SSC and the peak of stream discharge was quantified using cross-correlation analysis. For almost all events, SSCs were higher during the rising limb of the hydrograph for a given discharge, with SSC peaks occurring before discharge peaks, resulting in clockwise hysteresis (H > 1). The H indices increased (looser hysteresis loop) as the availability of sediments increased and as the lag between peaks in SSC and discharge was larger. A restriction of the proposed H index was that it could only be computed when stream discharge increased by more than 30% during a melt event.
机译：太浩湖流域的环境正在下降，部分原因是其支流的沉积物进入。许多研究通过收集水样并使用评级技术，通过离散采样程序估算了这些河流中的悬浮泥沙负荷。然而，这些支流中的流量排放与悬浮沉积物浓度（SSC）之间的关系在以融雪为主的水文图的上升和下降分支期间是不同的。由于这种滞后效应，泥沙定额曲线不能很好地预测河流中悬浮泥沙的动力学。在这项研究中，使用浊度计研究了悬浮泥沙的输送，以提供融雪期间泥沙浓度的连续记录。还研究了悬浮泥沙输送中的滞后现象，并使用H指数进行了量化，该H指数是水位图不同阶段曲线下面积的比率。使用互相关分析量化了SSC峰值和流排放峰值之间的时间滞后。对于几乎所有事件，在给定流量的水文测量仪上升肢期间，SSC都较高，SSC峰值出现在流量峰值之前，导致顺时针滞后（H> 1）。 H指数随着沉积物的可利用性增加以及SSC的峰值与流量之间的滞后时间变大而增加（较弱的磁滞回线）。提出的H指数的限制是只能在融化过程中料流排放增加30％以上时才能计算。

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