In response to the severe sedimentation in the anabranching channels of the Lunzhou reach caused by the catastrophic “22·6” flood event in the Beijiang River

this study developed a coupled one-dimensional/two-dimensional( 1D-2D) hydrodynamic and sediment transport model to systematically investigate the hydrodynamic mechanisms through which emergency dredging restores flood conveyance capacity in anabranching channels. A novel four-dimensional coordinated management framework integrating dredging

flood conveyance

ecological restoration

and resource utilization was proposed. By applying graded resource utilization technologies based on material quality

an overall beneficial reuse rate of82. 5% of the dredged material was achieved

establishing a closed-loop system linking dredging

ecological restoration

and economic benefits

and demonstrating the synergistic effects of emergency dredging and circular resource utilization.The results show that the dredging project increased the flow split ratio of the right branch by 6%

reduced the maximum flow obstruction ratio by 31. 4%

and improved the flood conveyance efficiency coefficient( η) from 0. 89 to 0. 96. Peak flow velocities decreased by 11. 0% ～ 20. 4%

the extent of high-velocity zones was reduced by 35%

and riverbed scour risk was effectively mitigated. In addition

the dredged material was successfully utilized as a valuable resource. This study proposes a collaborative post-disaster management paradigm integrating hydrodynamic regulation and environmental restoration for anabranching channels

providing theoretical insights and technical support for enhancing water security resilience in the Guangdong-Hong Kong-Macao Greater Bay Area.