Abstract: The use of Dujiatai flood diversion channel in 2005 and 2011 provided a new idea of regulation mode for medium and small floods in Hanjiang River, achieving the goal of minimum loss and maximum safety. According to the present condition and regulation schemes of Dujiatai diversion area, a 1D and 2D coupled numerical model was established on the basis of hydrodynamic software MIKE to simulate the flood discharge ability and effects of Dujiatai flood diversion channel. Hanjiang River, Dujiatai flood diversion channel and inner embankments are taken into account in the model.Results show that the safe discharge of Dujiatai flood channel is about 2000-2500 m³/s, except for the insufficient embankment top elevations at Xinnongyuan and Zhangchen Lake when Hankou station is at a higher water level. In addition, when Hanjiang River suffers from design flood, operation of Dujiatai flood diversion channel in priortity could obviously reduce flood losses. In conclusion, the results offer reference for improving regulation modes of Dujiatai diversion project and other similar projects.

Key words: Dujiatai diversion and storage project, flood discharge capacity, MIKE, flood propagation, numerical simulation