Bed Load Sediment Transport in an Ephemeral Stream and a Comparison with Seasonal and Perennial Counterparts
Bed Load Sediment Transport in an Ephemeral Stream and a Comparison with Seasonal and Perennial Counterparts
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DOI：
10.1029/94wr02233
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发表时间：
1995-03
影响因子：
5.4
通讯作者：
I. Reid;J. Laronne
中科院分区：
文献类型：
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作者：
I. Reid;J. Laronne
推移质泥沙通量在一个短暂的通道，纳哈勒Yatir，被证明是一个比较简单的函数流功率，并达到几个数量级高于最大值在类似的水平，流功率在常年同行。水道平均淹没单位通量率记录高达4.3 kg s−1 m−1，而在水道中心，记录的最高速率为6.5 kg s− 1 m −1。运输效率至少比有可比数据的其他渠道高一个数量级，平均而言，是橡树溪的400倍。这些差异是由亚提尔的床没有装甲这一事实解释的。据推测，该沙漠流域的无植被性质提供了各种尺寸的沉积物的充足供应，这与山洪过程线的快速衰退和长时间的无流量一起，阻碍了装甲层的发展。通量率不受沉积物供应的限制，因为它们是在常年渠道。纳哈尔亚蒂尔和橡树溪代表了一个光谱的两端，之间是季节性和不太好装甲常年流。输运效率的变化很大，每个流，从一个流到另一个流，这表明它可能不可能很容易地将其纳入推移质方程，以提高预测水平。
Bed load sediment flux in an ephemeral channel, the Nahal Yatir, is shown to be a comparatively simple function of stream power and to reach levels that are several orders of magnitude higher than maxima measured at similar levels of stream power in perennial counterparts. Channel average submerged unit flux rates are recorded as high as 4.3 kg s−1 m−1, while at the center of the channel, the highest rate recorded is 6.5 kg s−1m−1. Transport efficiency is at least an order of magnitude higher than in other channels for which there are comparable data and, on average, as much as 400 times that of Oak Creek. These differences are explained by the fact that the bed of the Yatir is not armored. It is surmised that the unvegetated nature of this desert watershed provides ample supplies of sediment of all sizes and that this, together with the rapid recession of the flash flood hydrograph and the extended periods of no flow, discourages the development of an armor layer. The flux rates are not sediment supply-limited, as they are in perennial channels. Nahal Yatir and Oak Creek represent two ends of a spectrum, between which come seasonal and less well armored perennial streams. Transport efficiency is shown to vary considerably for each stream and from one stream to another, suggesting that it may not be possible to incorporate it easily into bed load equations in order to improve levels of prediction.