Scaling relationships between bed load volumes, transport distances, and stream power in steep mountain channels
Scaling relationships between bed load volumes, transport distances, and stream power in steep mountain channels
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DOI：
10.1002/2013jf002874
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发表时间：
2014-03
期刊：
影响因子：
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通讯作者：
J. Schneider;J. Turowski;D. Rickenmann;Ramon Hegglin;S. Arrigo;L. Mao;J. Kirchner
中科院分区：
文献类型：
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作者：
J. Schneider;J. Turowski;D. Rickenmann;Ramon Hegglin;S. Arrigo;L. Mao;J. Kirchner
在山区，风暴事件期间的推移质输运既是地貌变化的一个因素，也是一种重大的自然灾害。因此，预测推移质输沙是河流地貌学和自然灾害风险评估的核心挑战。风暴期间推移质输移取决于河床冲刷的宽度和深度，以及单个泥沙颗粒的输移距离。我们跟踪个人砾石在两个陡峭的山溪，Erlenbach（瑞士）和里约警戒线（意大利），使用磁性和射频识别标签，并测量其推移质输沙率使用校准的地震检波器推移质传感器在Erlenbach和推移质陷阱在里约警戒线。示踪剂输送距离和推移质体积表现出近似幂律缩放与峰值流功率和累积流能量的个人水文事件。推移质体积缩放更陡峭的峰值流功率和累积流能量比示踪剂运输距离，推移质体积缩放约为运输距离的三次方。这些观察结果表明，大型推移质输运事件主要是通过冲刷河床更深更宽，其次才是通过将流动的泥沙输送得更远。使用沉积物连续性方程，我们可以估计活跃的传输层的平均有效厚度，平均在整个通道宽度和单个流量事件的持续时间。这一活跃层的厚度也遵循近似幂律缩放与峰值流功率和累积流能量和范围高达0.57米的Erlenbach，大致与独立的测量。
Bed load transport during storm events is both an agent of geomorphic change and a significant natural hazard in mountain regions. Thus, predicting bed load transport is a central challenge in fluvial geomorphology and natural hazard risk assessment. Bed load transport during storm events depends on the width and depth of bed scour, as well as the transport distances of individual sediment grains. We traced individual gravels in two steep mountain streams, the Erlenbach (Switzerland) and Rio Cordon (Italy), using magnetic and radio frequency identification tags, and measured their bed load transport rates using calibrated geophone bed load sensors in the Erlenbach and a bed load trap in the Rio Cordon. Tracer transport distances and bed load volumes exhibited approximate power law scaling with both the peak stream power and the cumulative stream energy of individual hydrologic events. Bed load volumes scaled much more steeply with peak stream power and cumulative stream energy than tracer transport distances did, and bed load volumes scaled as roughly the third power of transport distances. These observations imply that large bed load transport events become large primarily by scouring the bed deeper and wider, and only secondarily by transporting the mobilized sediment farther. Using the sediment continuity equation, we can estimate the mean effective thickness of the actively transported layer, averaged over the entire channel width and the duration of individual flow events. This active layer thickness also followed approximate power law scaling with peak stream power and cumulative stream energy and ranged up to 0.57 m in the Erlenbach, broadly consistent with independent measurements.