Past, present and future of a meandering river in the Bolivian Amazon basin
Past, present and future of a meandering river in the Bolivian Amazon basin
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DOI：
10.1002/esp.5058
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发表时间：
2021-02
影响因子：
3.3
通讯作者：
Kattia Rubi Arnez Ferrel;J. Nelson;Y. Shimizu;T. Kyuka
中科院分区：
文献类型：
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作者：
Kattia Rubi Arnez Ferrel;J. Nelson;Y. Shimizu;T. Kyuka
在亚马逊盆地的小河上进行实地观测不太常见，因为它们位置偏远，很难到达。在这里，我们通过遥感分析和野外工作，展示了位于亚马逊盆地上游前陆的一条小河-伊奇洛河的平面演变和河床地形。通过跟踪30年来的平面变化，我们确定了控制伊奇洛河曲流迁徙速度的因素：截流、气候和人类干预。数据表明，截颈是伊奇洛河的主要控制措施，年截流密度为0.022条/公里。此外，以高降水事件的形式确定了气候控制，这些事件可能促进了截流、曲流河迁移率的增加和航道拓宽。伊基洛河的宽度分布可以用广义极值分布和逆高斯分布来很好地描述。在两个预期断颈的地点，分析了伊奇洛河曲折迁移率的时空变异性。分析这两个点的颈部距离，我们预测会出现一个新的截止点。水深测量和运动摄影测量的结构相结合的方法向我们展示了高分辨率的伊奇罗河床地形和堤岸，在那里发现了两个冲刷坑。最后，我们讨论了伊基洛河的平面变化对其河岸边建立的社区的影响。
Field observations on small rivers of the Amazon basin are less common due to their remote location and difficult accessibility. Here we show, through remote sensing analysis and field works, the planform evolution and riverbed topography of a small river located in the upper foreland Amazon basin, the Ichilo River. By tracking planform changes over 30 years, we identified the factors that control meander migration rates in the Ichilo River: cutoffs, climate and human interventions. The data suggest that neck cutoffs are the main controls in the Ichilo River, with an annual density of 0.022 cutoffs/km. In addition, climate controls have been identified in the form of high‐precipitation events that may have promoted cutoffs, an increase in meander migration rate and channel widening. The width distribution of the Ichilo River is well represented by general extreme value and inverse Gaussian distributions. The spatiotemporal variability of meandering migration rates in the Ichilo River is analysed in two locations where neck cutoffs are expected. Analysing the distance across the neck in these two points, we predict the occurrence of a new cutoff. The combined methodology of bathymetric surveys and structure from motion photogrammetry shows us the Ichilo riverbed topography and banks at high resolution, where two scour holes were identified. Finally, we discuss the impact of planform changes of the Ichilo River on communities that are established along its riverbanks.