根据三峡工程大江截流期间收集到的截流河段、导流明渠、二期上下围堰口门区的水位、流速、流量、河床地形、水面流态等监测资料，分析研究了截流河段（尤其是动态的龙口）水力要素的变化规律及其相互关系。分析表明，龙口纵、横断面的流速分布受戗堤进占与平抛垫底施工和上游来水来沙的综合影响。围堰渗流量的监测对分析明渠分流比、石渣戗堤稳定研究起到了补充作用 According to the monitoring data such as water level, flow velocity, flow rate, river bed topography and water surface flow pattern collected in the section of the Three Gorges Dam during the river closure, the diversion channel, the diversion channel and the upper and lower cofferdams, Is a dynamic Longkou) changes in the hydraulic elements and their relationship. The analysis shows that the velocity distribution in the longitudinal and cross sections of the Longkou is affected by the comprehensive utilization of embankment, flat bottom construction and upstream water and sand flow. Cofferdam seepage flow monitoring plays a complementary role in the analysis of open channel diversion ratio and gravel embankment stability research