自1950 年以来,随着下荆江裁弯、葛洲坝截流和三峡水库等水利工程的相继建设,荆江河段藕池口分流比逐年减少,而且近期出现长时段的断流问题。为认识汛期流量变化对水动力沿程调整的影响,基于实测地形数据和水文资料建立二维水动力数学模型,可为藕池河段河道整治、疏浚和水系连通工程实践提供参考。结果表明:中、低来流量条件下河道最大流速出现在梅田湖河段;中、高来流量下由于藕池河中支分流能力增加,黄金闸下游水流流速明显减少,最小流速集中在黄金闸—殷家洲河段。受逆坡作用影响下殷家洲河段水流动力轴线自上游开始逐渐偏向右岸,最大流速出现在梅田湖进口靠近河道左岸的口门处,右汊分流比受流量级和过流断面面积控制。

Since the 1950s, the flow diversion ratio of Ouchi River in the Jingjiang reach of middle Yangtze River has decreased yearly and even experienced long-time zero-flow in recent years with the successive construction of water conservancy projects such as the cutoffs of lower Jingjiang River, the Gezhouba Dam, and the Three Gorges Reservoir. To understand the impact of flow discharge changes in flood season on the hydrodynamics along the reach, a 2D mathematical model using MIKE 21 was established based on the measured topographic data and hydrological data in the purpose of providing reference for the practice of river regulation, dredging and river network connection engineering in the Ouchi River. Under medium and low incoming discharge, the maximum flow velocity of the river channel appeared in the Meitian Lake reach. Under medium and high incoming discharge, due to the increase in the diversion capacity of the middle branch of Ouchi River, the flow velocity in downstream Huangjinzha reduced significantly, and the minimum flow velocity concentrated in the Huangjinzha-Yinjiazhou reach. Affected by the backward slope, the hydrodynamic axis of the Yinjiazhou segment gradually shifted to the right bank, and the maximum velocity was observed at the entrance of Meitian Lake, close to the channel on the left bank. Flow diversion in the right branch was mainly controlled by incoming discharge stage and cross section area.