Study on Saltwater Intrusion in the Yangtze River Estuary by 3D Numerical Model

Yangtze River is the biggest river in China, the quantity of freshwater flowing in ocean is very huge. And it is middling tidal estuary that is affected by tidal current obviously. This area is a very complex system, which has three-order branches and four outlets to the East Sea. The estuary is influenced by tide and freshwater, And saltwater intrusion is complex either. Therefore, studying on the saltwater intrusion not only deepen the cognition of the intrusion regulation and dynamical factors, but also provides scientific gists for water intake from Yangtze estuary and can reduce the influence of saltwater intrusion. The saltwater intrusion process over the periods at flood season in the entire study area was simulated. The salinity distribution of the situation accords with that measured data reflected. The gradient of salinity horizontal diffusion decrease upstream from the sea, the salinity of North Branch has always been higher than that of South Branch. It reproduces the basic law of the saltwater intrusion in the Yangtze estuary.