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>Riverbed erosion of the final 565 kilometers of the Yangtze River (Changjiang) following construction of the Three Gorges Dam
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Riverbed erosion of the final 565 kilometers of the Yangtze River (Changjiang) following construction of the Three Gorges Dam
The world’s largest hydropower dam, the Three Gorges Dam (TGD), spans the upper Yangtze River in China, creating a 660-km long and 1.1-km wide reservoir upstream. Several recent studies reported a considerable decline in sediment load of the Lowermost Yangtze River (LmYR) and a rapid erosion in the subaqueous delta of the river mouth after the closure of the TGD in 2003. However, it is unknown if the TGD construction has also affected river channel and bed formation of the LmYR. In this study, we compared bathymetric data of the last 565 kilometers of the Yangtze River’s channel between 1998 and 2013. We found severe channel erosion following the TGD closure, with local riverbed erosion up to 10 m deep. The total volume of net erosion from the 565-km channel amounted to 1.85 billion m3, an equivalent of 2.59 billion metric tons of sediment, assuming a bulk density of 1.4 t/m3 for the riverbed material. The largest erosion occurred in a 100-km reach close to the Yangtze River mouth, contributing up to 73% of the total net eroded channel volume.
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机译：世界上最大的水电大坝三峡大坝（TGD）跨越中国的长江上游，在上游形成了660公里长，1.1公里宽的水库。最近的几项研究报告说，2003年三峡工程关闭后，长江下游的沉积物负荷显着下降，河口水下三角洲的侵蚀迅速。但是，三峡工程的建设是否也影响了LmYR的河道和河床形成。在这项研究中，我们比较了1998年至2013年长江最后565公里航道的水深数据。我们发现，在TGD封堵之后，河道遭受了严重侵蚀，局部河床侵蚀达10μm深。假设堆密度为1.4 t / m 3 <，则565公里航道的净侵蚀总量为18.5亿m 3 ，相当于25.9亿吨沉积物。 / sup>用于河床材料。最大的侵蚀发生在长江口附近100公里处，占侵蚀总河道总量的73％。
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