Mountain streams: Modeling hydraulics and substance transport
Mountain streams: Modeling hydraulics and substance transport
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山间溪流：模拟水力学和物质运输
DOI：
10.1061/(asce)0733-9372(2005)131:2(252
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发表时间：
2005
影响因子：
2.2
通讯作者：
P. Reichert
中科院分区：
文献类型：
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作者：
W. Meier;P. Reichert
一维模型是预测水力学、物质输送、温度和河流水质的有用工具，与横向混合距离相比，河流的流动距离较长。然而，将这种模型应用于山间溪流是很困难的，因为除了小尺度的河床粗糙度之外，还必须在空间平均尺度上考虑大尺度粗糙度、河床几何形状的不规律性以及池和波纹序列的影响。用死区模型来表示砾石床中的水池、因河床不平整而导致的停滞区和间隙区，这使得物质输运的描述得到了极大的简化，但在基本机制的表达上是正确的。然而，与在增大的摩擦系数中包含这些影响相比，这种方法在参数可识别性方面导致了更严重的问题。为了克服这些问题，我们应用了一种针对无水池河段开发的摩擦估计器，然后能够识别死区体积和交换参数。在瑞士阿尔卑斯山南部的一个案例研究中，死区体积分数和在死区的停留时间与河流流量没有很大的关系，但这些参数在不同的河流段之间变化很大。这表明，对单一流动条件的示踪试验的评估显着降低了特定流段物质迁移的预测不确定性。
One-dimensional models are useful tools for predicting hydraulics, substance transport, temperature, and water quality in rivers for flow distances that are long compared to the lateral mixing distance. However, the application of such models to mountain streams is difficult because, in addition to small scale bed roughness, the effects of large-scale roughness, irregularity in bed geometry, and pool and riffle sequences have to be taken into account at a spatially averaged scale. Representation of pools, stagnant zones due to bed irregularity, and interstitial zones in the gravel bed with a dead zone model leads to a description of substance transport that is strongly simplified but correct in the representation of basic mechanisms. However, this approach leads to more severe problems regarding parameter identifiability compared to inclusion of these effects in an enlarged friction coefficient. To overcome these problems, we applied a friction estimator developed for river sections without pools and were then able to identify the dead zone volume and exchange parameters. In a case study in the southern Swiss Alps, the dead zone volume fraction and the residence time in the dead zone did not strongly depend on stream discharge, but these parameters varied strongly from one stream section to another. This indicates that the evaluation of a tracer test for one single flow condition significantly decreases prediction uncertainty of substance transport for a specific stream reach.