Study on impact of runoff on saltwater intruding from the North Branch in the Changjiang Estuary

A two-dimensional hydrodynamic force-salinity transport model in Yangtze River Estuary is established on the basis of analyzing the measured data and the adoption of MIKE21 model. This model is used to study the average daily distribution and changing patterns of the saline groups (i.e. salinity water lenses) in the South Branch that are from the North Branch while only the saltwater intrusion from the North Branch is considered. The impact of runoff on the transport of intruding saline group and its salinity changes is studied using the established model. It is found by the study that the average location and time changes for tidal cycles of intruding saline group cores in watercourses in the Estuary are line up to the Gompertz model. And, the non-linear relationship of parameters and runoff volume in the Gompertz model is available.