Based on the data of water quality at Datong Station, which is at tidal limit in the Changjiang Estuary, variations of concentrations and fluxes of the dissolved inorganic nitrogen and phosphorus were discussed.

The Tong Cheng Reach is the lower part of the Yangtze River, where the water abstraction is active and gives impact both on the location of the tidal limit and on that of the tidal current limit.