Stability of the Stratification of Water Bodies in the North Passage of the Yangtze River Estuary Based on the EFDC Model

To study the stratified stability of a water column in the North Passage of the Yangtze River Estuary, a numerical model of the hydrodynamics of this estuary is established using the EFDC model. On the basis of EFDC results, this paper derives and provides the discriminative index of water body stability caused by salinity and analyzes the along-range variation in water body stratification stability in the North Passage of the Yangtze River Estuary and the periodic variation at a key location(bend area) based on the simulation results of the numerical model. This work shows that the water body in the bend area varies between mixed and stratified types, and the vertical average flow velocity has a good negative correlation with the differential velocity between the surface and bottom layers of the water body. The model simulation results validate the formulae for the stratified stability discriminant during spring tides.