Measurements of flow patterns, sediment transport, and morphological change in two very sharp bends of the Middle Yangtze River

We investigated the morphological changes, patterns of mean flow, secondary flow, and sediment transport around two very sharp bends in the Middle Yangtze River based on field campagns. We found that the deformation pattern is characterized by erosion of point bars and deposition of outer-bank benches, and the patterns of primary and secondary flow and sediment transport in the sharp bends undergoing significant morphological changes differ from those bends that of equilibrium river systems. The velocity data shows the ADCP measured 3D velocities (X,Y,Z) at 12 transects of the sharp bends of QGL and GYZ in the MYR. The sediment data shows the transport rates and median diameters of suspended and bed sediments and suspended sediment concentrations at 12 measured transects. The measurements of long-term morphorlogical change includes the cross-sectional profiles of 4 typical cross sections and the deformation depth duiring the period 2002-2018 around the QGL and GYZ bends. The deformation depth are shown with the tif-format (deformation depth (2002-2018)), which can be viewed in the open-source software QGIS planform (https://www.qgis.org/en/site/).本研究基于野外实测工作，针对长江中游（Middle Yangtze River, MYR）两处急弯河道，开展了河道地貌演变、主流流态、副流流态以及泥沙输移特征的调查分析。研究发现，该类急弯河道的变形模式以边滩（point bar）侵蚀与岸滩外侧阶地沉积为典型特征；且发生显著地貌演变的急弯河道，其主流、副流及泥沙输移模式与平衡态河系弯道存在显著差异。流速数据集包含长江中游QGL与GYZ两处急弯河道共12个测流断面的声学多普勒流速剖面仪（Acoustic Doppler Current Profiler, ADCP）实测三维（X、Y、Z方向）流速数据。泥沙数据集涵盖上述12个测流断面的悬移质与床沙输沙率、中值粒径，以及悬沙浓度数据。长期地貌演变实测数据包含QGL与GYZ弯道周边2002年至2018年间的4条典型横断面地形剖面，以及该时段内的河道变形深度数据。河道变形深度数据以tif格式（命名为deformation depth (2002-2018)）存储，可通过开源地理信息软件QGIS的平面视图功能打开查看，其官方网址为https://www.qgis.org/en/site/。