High-quality wind field data are key to improving the accuracy of storm surge simulations in coastal and estuarine water. These data are also of great significance in studying the dynamic processes in coastal areas and safeguarding human engineering structures. A directional correction method for ECMWF reanalysis wind data was proposed in this paper based on the correlation with the measured wind speed and direction. The results show that the accuracies of wind speed and direction were improved after being modified by the correction method proposed in this paper. The modified wind data were applied to drive the storm surge model of the Yangtze Estuary for typhoon events, which resulted in a significant improvement to the accuracy of hindcasted water levels. The error of the hindcasted highest water levels was reduced by 16–19 cm.

Saltwater intrusion threatens freshwater availability in the Yangtze Estuary. The effects of the Deep Waterway Project in the North Passage have been extensively studied, whereas the influence of the Channel Regulation Project in the South Passage (SPCRP) recently implemented has received little attention. A calibrated depth-averaged Delft3D model is used to compare no-project (C0), Phase-1 (C1), and Phases 1 + 2 (C12) scenarios without dredging and quantify changes in flow division, salinity, and cross-sectional salt transport. The results show that Phase-1 has a significant effect on hydrodynamic response. Under spring-tide conditions, the South Passage share of the combined North and South Passage discharge decreases from 0.54 (C0) to 0.24 (C1) and 0.21 (C12), while the net water flux at the upstream South Passage section decreases from 2002 m³/s (C0) to 767 m³/s (C1) and 711 m³/s (C12). Salinity increases of up to 3.63 ppt in the South Passage and 3.03 ppt in the North Passage occur under C1 relative to C0, whereas Phase-2 produces only localized reductions of up to 0.87 ppt and 0.81 ppt relative to C1. Changes are concentrated in the South and North Passages, while the North Channel remains relatively unaffected. At the upstream South Passage section, spring-tide salinity transport is landward in all scenarios, increasing from −4345 ppt·m³/s (C0) to −9788 ppt·m³/s (C1) and −9844 ppt·m³/s (C12), despite seaward net water flux. Neap-tide transport is seaward. The spring-tide landward transport is controlled by a strongly negative resolved tidal covariance, consistent with higher flood-tide than ebb-tide salinity. These results provide a basis for linking estuarine projects with saltwater intrusion risk management.