ABSTRACT
Influenced by tidal, high salt concentration water of the sea floods into the estuary and moves forward to the upstream, combined with the diffusion and mixing process of salt and fresh water. When the inland salt content exceeds a certain standard and the formed water is uaually called saline tide. Research on saltwater began at 1930s. The Dutch lab of Delft did a lot of fundamental work, later researchers (Pritchard 1952, Ippen & Harleman 1961, Hansen & Rattray 1965, Hansen & Rattray 1966, Simmons & Brown 1969) also did lots of pioneering research work on the phenomenon and process of saltwater movement, which focused on the length of the saltwater intrusion, the mixing type, density circulation, as well as the relationship of estuarine circulation and maximum turbidity zone. Numerical models about saltwater intrusion began to develop. Based on the study of large estuarine saltwater intrusion curve, the researcher (Savenije 1986, Savenije 1993) concluded four types of saltwater intrusion models, namely, “degradation”, “bell”, “apex of arch” and “hump” to simulate or predict salty tide estuary. The domestic study of saline intrusion in estuary started relatively late and mainly focused on theYangtze River delta and the Pearl River delta (Mao et al. 2004, Bao & Ren 2005).
