Study on Flow Pattern and Characteristics of Sediment Deposition in Tidal Reach of Yangtze River

Taking Nanjing macha river mouth of Yangtze river for example, a two-dimensional flow and sediment mathematical model was established to study flow pattern and characteristics of sediment deposition. The results of flow pattern show that there isn’t flood tidal current in the Nanjing baguazhou reach, but with tidal level alternating between flood tide and ebb tide, there is flood tidal current inside the river mouth under the condition of flood water. The calculation results of sediment deposition show that the sediment deposition is connected with the flow character and the incoming water and sediment condition. The deposition thickness at macha river mouth is much more than that of inside the macha river, and the sediment deposition in 1998 is much more than that of in 2006. With the increasing of calculational time, the deposition thickness per year decreases.