Evaluation of the effect of porous check dam location on fine sediment retention (a case study)
Evaluation of the effect of porous check dam location on fine sediment retention (a case study)
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DOI：
10.1007/s10661-008-0318-2
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发表时间：
2009-05
影响因子：
3
通讯作者：
A. Hassanli;A. E. Nameghi;S. Beecham
中科院分区：
文献类型：
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作者：
A. Hassanli;A. E. Nameghi;S. Beecham
本研究旨在评估多孔拦水坝位置对伊朗南部Droodzan流域细沉积物截留的影响。五个长流与几个多孔检查坝，超过27岁进行了研究。在每条河流中，选择三个淤地坝：在最上游段、中间段和最下游段进行分析。收集了一些来自截留沉积物和河岸（邻近淤地坝）原状土壤的样品。实验室分析表明，从未受干扰的银行采取的土壤样品具有较小的颗粒尺寸相比，捕获的沉积物。结果表明，设置在下游较远河段的淤地坝比设置在中游河段的淤地坝拦沙效果更好。同时，中部淤地坝比上游淤地坝更有效。沉积物结构的比较也表明，粘土和粉砂的一部分被拦水坝从下游部分向上游部分减少。因此，无论何时，只要拦河坝的主要功能是截留细颗粒沉积物，它们似乎都应该位于河流的远下游部分。试验分析表明，在多孔性淤地坝中，用破碎的、棱角状的岩石代替圆形岩石，可以提高淤地坝对细颗粒泥沙的拦蓄效果。对溃决的淤地坝的分析还表明，淤地坝下岸的冲刷是导致大坝溃决的主要原因。
This study was carried out to evaluate the influence of porous check dam location on the retention of fine sediments in the Droodzan watershed in Southern Iran. Five long streams with several porous check dams that were more than 27 years old were studied. In each stream three check dams: at the very upstream section, at the middle section and at the far downstream section were selected for analysis. A number of samples from trapped sediments and from the undisturbed soils in the stream banks (adjacent to the check dams) were collected. Laboratory analysis showed that the soil samples taken from undisturbed banks have smaller particle sizes compared to the trapped sediments. The results indicated that the check dams located at the far downstream sections were more efficient at trapping fine sediment than those located at the middle sections. Also the check dams located at the middle sections were more effective than those located at the upstream sections. Comparison of sediment texture also showed that the portion of clay and silt trapped by the check dams decreased from the downstream sections toward the upstream sections. Hence, whenever, the retention of fine sediments is the primary function of the check dams, it appears that they should be located in the far downstream sections of a stream. The experimental analysis indicated that using broken and angular rocks instead of rounded rocks in porous check dam’s construction improves the effectiveness of the check dams for the retention of fine sediments. The analysis of the failed check dams also showed that erosion of the bank sides underneath the check dams is the primary cause of dam collapse.