Measures for mitigating the shrinking of the North Branch of Changjiang Estuary

Abstract

The atrophy of the entrance channel in the North Branch of Changjiang Estuary and the sediment supplied by landward tidal flow from the sea to the branch, threaten the sustainable use of the numerous ports and wharves along the riversides. Four different plans of two groups to mitigate the shrinking of the North Branch were proposed and tested. The plans in the first group aimed to expand the entrance channel and the upper section of the North Branch through dredging. The purpose of the plans in the second group was to reduce the landward tidal volume in the lower section of the North Branch to reduce the sediment import from the sea. The effects of these plans were simulated by a 2D computational hydrodynamic model, and the results such as tidal volume at different sections, the portions of tidal volume in different branches, and the high and low tidal levels at the monitoring points, were obtained and compared. After that, one plan from each group was recommended. The measures of the recommended plans have been mostly adopted in the report of Revision of the Comprehensive Regulation and Development Plan of the Changjiang Estuary.