Study on Hydraulic Regulation of a Tidal Plain River Network Based on Gate-Pump Joint Operation

Tidal plain river networks are often characterized by weak hydrodynamic conditions and limited self-purification capacity. In this study, a one-dimensional hydrodynamic-water quality model for the Haishu District of Ningbo City, China, was constructed using the self-developed software, the Drainage Water Modeling System (DWMS). To expand the spatial reach of water diversion, enhance river network fluidity, and improve water quality, this study systematically investigates the water diversion effects under different gate-pump joint operation modes using the verified model and introducing the concept of conservative substance. The simulation results show that, for tidal plain river networks with pollution sources along the rivers, the “pre-discharge then diversion” mode is the optimal operational scheme compared with the “simultaneous diversion and discharge” mode. This approach can increase the water renewal efficiency at the terminal river reach by 13% to 20%.