A historical review of sediment export–import shift in the North Branch of Changjiang Estuary

Net sediment transport is predominantly seaward in fluvial-dominated estuaries worldwide. However, a distributary branch the Changjiang Estuary, North Branch, undergoes net landward transport, which leads to severe channel aggradation. Its controlling mechanism and role of human activities remain insufficiently understood, although such knowledge necessary for better management restoration opportunities. In this study we revisit centennial hydro-morphodynamic evolution Branch based on historical maps, field data, satellite images provide synthesis regime change from ebb flood dominance. The was once major river ebb-dominant channel. Within alternative meandering channels sand bars developed. Deposition river-borne infilling branch, while tidal flat embankment reduces bankfull width modifies configuration, resulting profound decline sub-tidal flow partition rate. then becomes tide-dominant with an occurrence bores elongated ridges. Once dominance established, extensive reclamation enhances funnel-shaped planform, amplifying incoming tides initiating positive feedback process that links loss, import, Overall, shift combined result natural southeastward realignment deltaic reclamation. One option mitigate aggradation stop aggressive allow flats build up, might reduce import eventually lead morphodynamic equilibrium longer term. Understanding impact informative similar systems under strong interference.