Abstract: Based on the observation data and GIS approach,this study analyzes the fluvial morphology of some key channels in the Three Gorges fluctuating back water area.Results indicate that there are accumulated depositions in all these channels after the impoundment of the Three Gorges Reservoir.The accumulated deposition mainly exists in places such as slow-velocity zone in the concave bank.Therefore the hydrodynamic factor is of the most importance in the deposition.The hydrologic conditions and the reservoir ope...