Taking the reach with fluctuating backwater area in jiaokou hydroplant in xiujiang river , guanxi zhuang autonomous region for instance , this paper analyzes the water - sediment characteristics of the fluctuating backwater area , calculates the design level of this reach with samples of level and discharge , etc . , and propounds the determination method for the designed lowest navigable level of reach with fluctuating backwater area 以广西绣江交口电站的变动回水区河段为例，分析了变动回水区的水沙特性，分别利用水位、流量样本及不同方法计算与分析本河段的设计水位，提出了变动回水区河段设计最低通航水位的确定方法。
