In the last few decades, riverine sediment flux to the coastal zones has been decreasing globally. The sediment flux from rivers to seas is usually estimated based on the lowermost gauging stations free of tides in the rivers, for example the Yangtze River. Knowledge of decadal sediment budget and the morphological evolution in the tidal reach is still limited. Here, using historical bathymetry of the tidal reach of the Yangtze, the changes in the sediment budget and local morphology in this reach for three periods between 1970 and 2008 were investigated. In terms of input sediment flux, Period I 1970–1992 is a relatively steady period, Period II 1992–2003 is a decline period with a significant decrease in the sediment flux, and Period III 2003–2008 is a decline period after the closure of the Three Gorges Dam (TGD). The reach was nearly in equilibrium during Period I. Net erosion occurred in the reach during both the pre- and post-TGD decline periods 1992–2003 and 2003–2008, with annual erosion of approximately 65 and 37 Mt/yr, respectively. The contribution of the annual erosion in the reach to the annual sediment flux at the downstream end of the reach increased from around 16.9% during 1992–2003 to 19.1% during 2003–2008. These changes in the sediment budget are closely related to the decrease in the input sediment flux, coarsening of the sediment grain size after the closure of the TGD, and changes in the riverine water flux and tidal conditions. Characterized by a length scale of 4–32 km, local deposition/erosion patterns were quite complex, which relates to the complexity of the local geometry, bathymetry and flow condition. The horizontal location of the thalweg of the reach had limited changes during 1992–2008, likely owing to the fixed riverbank due to human intervention.

在过去的几十年中，全球范围内流向沿海地区的河流沉积物一直在减少。通常是根据河流（例如长江）中没有潮汐的最低测量站来估算从河流到海洋的沉积物通量。年代际沉积物预算和潮汐范围内形态演变的知识仍然有限。在这里，利用长江潮汐的历史测深法，研究了该潮汐在1970年至2008年之间三个时段的沉积物收支和局部形态的变化。就输入的泥沙通量而言，1970-1992年的I期是一个相对稳定的时期，1992-2003年的II期是一个下降期，其中泥沙通量显着下降，而2003-2008年的III期是一个封闭期之后的下降期。三峡大坝（TGD）。在第一阶段，河段几乎达到平衡。在TGD下降之前和之后的1992–2003年和2003–2008年期间，河段均发生了净侵蚀，年侵蚀分别约为65 Mt /年和37 Mt /年。河段的年侵蚀量对河段下游的年泥沙通量的贡献从1992–2003年的16.9％增至2003–2008年的19.1％。沉积物预算的这些变化与输入沉积物通量的减少，TGD封闭后沉积物粒度的粗化以及河流水通量和潮汐条件的变化密切相关。以4–32 km的长度尺度为特征，局部沉积/侵蚀模式非常复杂，这与局部几何形状，测深和流量条件的复杂性有关。