Is river avulsion style controlled by floodplain morphodynamics
Is river avulsion style controlled by floodplain morphodynamics
复制标题
河流撕脱方式是否受漫滩形态动力学控制
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
D. Edmonds
中科院分区：
文献类型：
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作者：
E. Hajek;D. Edmonds
河流迁移或撕脱是填充冲积盆地的基本过程。然而，很难预测撕脱模式，因为与不同撕脱样式相关的景观条件目前尚不清楚。现代河流中已记录了两种端部撕脱类型：渐进撕脱（在此期间，随着新河道的修建，发生了显着的洪泛区沉积）和切入式撕脱（在此期间，洪泛区侵蚀捕获了母河道的水流）。在这里，我们提出撕脱类型与漫滩水流侵蚀或沉积沉积物的趋势有关（即洪泛区形态动力学）。我们对洪泛区侵蚀和沉积率进行了比例比较，用形态动力学模型对其进行了测试，并显示了与建模结果一致的古代沉积物的现场数据。这些结果表明，洪泛区形态动力学可能决定河流如何迁移，并且评估洪泛区侵蚀和沉积的相对影响可能有助于预测撕扯系统中的沉积模式。
River relocation, or avulsion, is a fundamental process that fills alluvial basins. However, it is difficult to predict avulsion patterns because the landscape conditions associated with different avulsion styles are currently unknown. Two end-member avulsion styles have been documented in modern rivers: progradational avulsions, during which significant floodplain deposition occurs as a new channel is built, and incisional avulsions, during which floodplain erosion captures flow from a parent channel. Here we propose that avulsion style is related to the tendency for overbank flows to erode or deposit sediment (i.e., floodplain morphodynamics). We present a scaling comparison of floodplain erosion and deposition rates, test it with morphodynamic modeling, and show field data from ancient deposits that are consistent with modeling results. These results demonstrate that floodplain morphodynamics may determine how rivers relocate and that assessing the relative influence of floodplain erosion and deposition may be useful for predicting sedimentation patterns in avulsive systems.