Abstract: In plain tidal river network area, rapid urbanization with delayed corresponding changes of underlying surface have resulted in insufficient discharging capacity of river channels, together with uprising flood levels and more frequent waterlogging in villages and towns, severely impeding the local economic development. On the basis of expounding influential factors of waterlogging in villages and towns in plain tidal river network area, the impact of channel flood on waterlogging is quantified via numerical simulation with some typical villages and towns as case study. To simulate channel flood and inundation process in town precisely, both of the processes are simulated with hydrodynamic model. Results indicate that influenced by 50-year event flood and 100-year event flood, the discharge in town decreases by 25.17% and 55.24%, respectively, which evidently affects the river flood process in town. Moreover, the increase in return period of rainstorm intensifies the impact of discharge reduction on the expansion of inundated area. Extreme channel flood would expand the waterlogging area by approximately 22%, and would aggravate the waterlogging in villages and towns. The research findings provide reference for the waterlogging risk management for villages and towns in plain tidal river network areas.

Key words: plain tidal river network area, channel flood, waterlogging in villages and towns, discharge, numerical simulation