A sharp decline in the Sediment load at the seaward most Datong station (DTS) of the Yangtze River occurred at an average rate of 7.22 × 10⁶ t/yr since 1956, and this drop had a staircase pattern that can be divided into five distinct periods (1956–1968, 1969–1991, 1992–2002, 2003–2012, and 2013–2017). In this study, a new holistic basin‐wide Sediment Budget Method (SBM) was developed using sediment data from a total of 74 gauging stations (arguably the largest datasets so far) to estimate the sediment contributions to DTS from tributaries and mainstream. Our results show that the Jinsha River in upper basin between Panzhihua and Xiangjiaba used to be one of the largest contributors to DTS in 1956–2002 (16%–33%), but its contribution decreased sharply after 2003 due to the impoundment of Three Gorges Dam (TGD) and decreased further to nearly nil in 2013–2017 due to the impoundment of new cascade dams (CDs) which were upstream of TGD. In contrast, the mainstream between Yichang and Datong contributed 50%–64% of the DTS in 2003–2017, owing to the active channel erosion downstream of TGD. Before 2003 about 66%–84% of the DTS was contributed by the upper reach, but 72%–91% of the DTS was from the middle‐lower reaches after 2003, reflecting a drastic shift in sediment suppliers from upper to middle‐lower reaches. On average, the drop of DTS was 128.37 × 10⁶ t/yr due to TGD impoundment in 2003–2012 and 27.28 × 10⁶ t/yr due to CDs impoundment in 2013–2017 because of the reservoir trapping and the inhibition of historically eroding channels in the reservoir area. This new SBM can be applied to other large and small rivers around the world to track sediment sources/sinks and provide valuable results for sediment resource management.

中文翻译：

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1956年至2017年长江排沙量减少：时空变化及其成因

长江最靠海的大同站（DTS）的泥沙负荷急剧下降，平均速率为7.22×10 ^6。 自1956年以来每年t / yr，并且这种下降具有阶梯模式，可以分为五个不同的时期（1956–1968、1969–1991、1992–2002、2003–2012和2013–2017）。在这项研究中，使用来自总共74个测量站（可能是迄今为止最大的数据集）的泥沙数据，开发了一种新的全流域全沙预算方法（SBM），以估算支流和主流对DTS的泥沙贡献。我们的结果表明，攀枝花和向家坝之间的上游盆地金沙江曾经是DTS的最大贡献者之一（16％–33％），但由于三峡蓄水，其贡献在2003年后急剧下降。大坝（TGD）并在2013-2017年进一步减少到几乎为零，这是由于在TGD上游的新梯级大坝（CD）的蓄水所致。相比之下，由于TGD下游的活跃河道侵蚀，宜昌和大同之间的主流在2003-2017年贡献了DTS的50％-64％。在2003年之前，大约66％–84％的DTS由上游贡献，但是72％–91％的DTS来自中下游，这反映了沉积物供应商从上到下急剧变化。到达。平均而言，DTS的下降为128.37×10⁶ 吨/年由于在2003 - 2012年TGD蓄水和27.28×10 ⁶ 吨/年由于在2013年至2017年，因为贮存器俘获的光盘蓄水库区历史侵蚀通道的抑制。这种新的SBM可以应用于世界其他大河和小河，以追踪泥沙源/汇，并为泥沙资源管理提供有价值的成果。