Numerical simulation of impact of the upstream discharge on salinity at Qingcaosha reservoir

Saline intrusion in the Yangtze River Estuary has been an unavoidable problem which has a direct impact on water intakes for Shanghai´s public drinking, industrial and agricultural usage. By using the Delft3D model, a numerical model is set up for simulation of saltwater intrusion in the Yangtze River estuary. This model is used to study the saltwater intrusion and to predict the salinity changes around Qingcaosha reservoir under the different upstream flow discharge conditions, which related with the operations of the South to North Water Transfer and the Three Gorges. Finally, this paper presents the functional relationships between the salinity at the water intakes of the Qingcaosha reservoir and the fresh water discharge of the Yangtze River and gives out an alarming flow rate of 9,000m³/s at Datong gauging station to prevent the Qingcaosha reservoir from the salt water intrusion.