Where rivers jump course
Where rivers jump course
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DOI：
10.1126/science.abm1215
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发表时间：
2022-05-27
期刊：
影响因子：
56.9
通讯作者：
Ganti, Vamsi
中科院分区：
文献类型：
--
作者：
Brooke, Sam;Chadwick, Austin J.;Ganti, Vamsi
河流可以突然改变路径在罕见的事件称为撕脱，这导致毁灭性的洪水。由于这些特征的数据稀少，对撕脱位置的控制知之甚少。我们分析了近50年的卫星图像，记录了地球仪上的113处撕脱，表明撕脱位置有三种不同的控制。在风扇上的撕脱与山谷限制的变化相吻合，而三角洲上的撕脱主要集中在回水区内，这表明洪水期间空间流减速或加速的控制。然而，38%的三角洲上的撕脱发生在回水效应的上游。这些事件发生在热带和沙漠环境中的陡峭、沉积物丰富的河流中。我们的研究结果表明，三角洲上的撕脱位置是由洪水驱动的侵蚀，这是典型的局限于回水区，但可以延伸到上游陡峭，泥沙河流的上游范围。我们的研究结果阐明了撕脱灾害如何应对土地利用和气候变化。
Rivers can abruptly shift pathways in rare events called avulsions, which cause devastating floods. The controls on avulsion locations are poorly understood as a result of sparse data on such features. We analyzed nearly 50 years of satellite imagery and documented 113 avulsions across the globe that indicate three distinct controls on avulsion location. Avulsions on fans coincide with valley-confinement change, whereas avulsions on deltas are primarily clustered within the backwater zone, indicating a control by spatial flow deceleration or acceleration during floods. However, 38% of avulsions on deltas occurred upstream of backwater effects. These events occurred in steep, sediment-rich rivers in tropical and desert environments. Our results indicate that avulsion location on deltas is set by the upstream extent of flood-driven erosion, which is typically limited to the backwater zone but can extend far upstream in steep, sediment-laden rivers. Our findings elucidate how avulsion hazards might respond to land use and climate change.