Abstract: In recent years, high flood level lasts in the downstream of Dongjing river during flood period. Analysis shows that the United Dyke was surrounded in 1970s during the regulation project of Dongjing River, but deep groove dredging was inadequate. Moreover, reclamation and siltation of dyke in the bottomland are continued, which lead to high flood water level at Yanglinwei station in Dongjing river. In view of this, we analyze the flood control situation of Hanjiang river after the Danjiangkou dam’s heightening and the situation of Yangtze river after Three Gorges Reservoir’s impoundment. Furthermore, we determine suitable standard of flood control in the downstream of Dongjing river(4 250 m³/s as the import flow from Dongjing river, 28.28 m as the export water level of Hankou station, 31.0 m as the control water level of Yanglinwei station). Through channel dredging project, the discharge capacity in the downstream of Dongjing river is amplified effectively. We design three schemes for flood control . In scheme 1, current spacing of levee is unchanged and deep groove dredging is needed. Calculated results of two-dimensional mathematical model show that scheme 1 has advantages such as low investment, easy construction, and obvious reduction of flood water level, so we choose it as recommended scheme.

Key words: flood control, Dongjing river, flood control situation, United Dyke, channel dredging