Hydrodynamic transport in a human-regulated tidal flat water network of the Yellow River Delta: Hydrological connectivity enhancement and transport potential assessment

Hydrodynamic transport in human-regulated tidal flat water networks plays a critical role in ecological water replenishment and wetland restoration. However, the relationship between network topology and hydrodynamic response remains insufficiently understood, limiting the optimization of ecological water diversion systems. This study focused on the water network of the Yiqian’er Nature Reserve in the Yellow River Delta. A hydrological connectivity enhancement method was proposed based on the classical connectivity theory and energy dissipation equation. Subsequently, a two-dimensional hydrodynamic sediment model was combined with graph theory analysis to explore how network topology controls hydrodynamic transport during ecological water replenishment. The results indicate that triangulated channel layouts can effectively enhance the structural connectivity, while the optimal channel turning radius is positively associated with water depth and negatively associated with roughness. Simulated kinetic energy density (KED) exhibits distinct spatial heterogeneity, with high-energy regions concentrated in main transport channels and channels adjacent to the water gates. Statistical analysis demonstrates that channel participation in multiple source–outlet transport paths is strongly correlated with KED, indicating that network topology exerts a significant control on hydrodynamic transport. Based on these findings, a Transport Potential Index ( T P I ) is developed using multi-path participation, source accessibility, and path proximity as structural predictors in a random forest machine learning model, achieving an RMSE of 0.08 and an R 2 of 0.89. The proposed framework provides an efficient approach for transport potential of network structure and offers practical references for ecological water network optimization and water replenishment management in engineered coastal wetlands.