Metrics for assessing the downstream effects of dams
Metrics for assessing the downstream effects of dams
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DOI：
10.1029/2006wr005092
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发表时间：
2008-04-05
影响因子：
5.4
通讯作者：
Wilcock, Peter R.
中科院分区：
文献类型：
--
作者：
Schmidt, John C.;Wilcock, Peter R.
我们评估了三个指标，代表了大坝下游河道变化的驱动因素。沉积物供应和输送能力之间的平衡确定了沉积物短缺或过剩的条件。希尔兹数表示坝后水流的能力和泥沙不足条件下的下切潜力。坝前和坝后的洪水流量比提供了一个衡量河道变化的尺度和速率，特别是宽度。这些指标是针对美国西部4000多公里的一些主要河流计算的。这些河流中有60%以上处于泥沙亏损状态，只有少数河段处于泥沙盈余状态。沉积物平衡可用于评估逆转不希望出现的亏损或盈余状况所涉及的相对努力。
We evaluate three metrics representing the drivers of channel change downstream from dams. A balance between changes in sediment supply and transport capacity identifies conditions of sediment deficit or surplus. A Shields number represents the competence of postdam flows and the potential for incision under conditions of sediment deficit. A ratio of postdam to predam flood discharge provides a metric for the scale and rate of channel change, especially width. The metrics are calculated for more than 4000 km of some of the major rivers in the western United States. More than 60% of these rivers are in sediment deficit, and only a few reaches are in sediment surplus. The sediment balance can be used to assess the relative effort involved in reversing undesired conditions of deficit or surplus.