The Three Gorges Project approach channel flow of a reasonable size of Flushing Abstract: This paper a systematic comparison of the Three Gorges Project and Gezhouba project specific conditions, combined with sediment physical and mathematical models of research and put forward the Three Gorges channel quoted a reasonable size Flushing flows. The Three Gorges Project can be smaller than the Gezhouba project “small flow safari” measures to achieve “water will move sand.” Under normal conditions, the approach channel safari size of the facility control 4000m3 / s within the range, we can achieve very good results Flushing; if safari to give further consideration to reduce reservoir water level of small magnitude, it still can be further reduced safari Flushing flow or increase the effect. Scouring the Department of lowering the water level of non-structural measures, could serve as a future in the use of margin of safety. This paper suggests, the Three Gorges Project with 4000m3 / s the size of the sand-flushing flow. Keywords: Three Gorges Project approach channel silt sand small flow of water will move 1 Introduction Three Gorges Project is to improve the navigation conditions in the upper reaches of the Yangtze River shipping conditions of the key. To this end, the Three Gorges Project layout of the two-five-sets navigation lock and the vertical ship lift construction, so that navigation Gezhouba project size and the same three-wire locks. According to Gezhouba project experience and the Three Gorges project sediment research 1 4, in the engineering application of the latter part of the dam area of the sediment deposition would be more serious approach channel upstream and downstream silting arrangement of a certain length of separation levee is necessary to The. To this end the Three Gorges downstream approach channel with a long separation levee would be quoted separately from the mainstream channel, the upstream approach channel will be used to build a lock, ship lift the temporary ship lock approach channel, and converted by the flushing sluice include all the so-called “ the whole package “separation levee program. As the temporary ship lock of the gap can be converted to be able to discharge 2500m3 / s of flushing sluice, so “full package” program has provided an important safari safari facilities. While anti-down approach channel to build a sludge separation levee, but the upper and lower approach channel is still a great amount of sediment deposition during the year. According to research statistics, to the latter part of the upstream and downstream approach channel of the navigation-deposition volume in more than 1 million m3. Navigation conditions, taking into account the limitations and deposition non-uniformity in time alone would be difficult to cope with mechanical dredging, and must take into account a certain amount of water safari facilities. Gezhouba project a “hydrostatic off ships, moving water will sand” 7 has been proven successful experience in the Three Gorges Project should learn from. However, the Three Gorges and Gezhouba project there is any difference, the Three Gorges Project can make use of Gezhouba project does not have favorable conditions, instead of copying the size of the Gezhouba the safari. Three Gorges “moving water will sand” scale should be based on their specific situation analysis to decide. According to the author in recent years, the Three Gorges Project on the upstream and downstream approach channel sedimentation countermeasures physical model test and mathematical model study, a detailed analysis of the Three Gorges Project on the basis of favorable conditions proposed in this paper can be “small flow safari” measures to achieve the Three Gorges project, “moving water will sand”, citing the size of channel sand-flushing facilities, control the 4000m3 / s within the range, we can achieve very good results safari. If we further consider lowering the reservoir water level and other non-structural measures, safari flow can also be reduced, which can serve as a room will help to ensure the smooth flow of the Three Gorges down approach channel. 2 Gezhouba Engineering and Comparison of the Three Gorges project safari conditions Gezhouba project to move water will sand approach to the maintenance of upstream and downstream approach channel has played a decisive role, it is worthy of the Three Gorges Project reference. However, due to the Three Gorges and Gezhouba project, after all, there are differences, quantitative decided that the scale of the Three Gorges Project Flushing flows should be read with the Three Gorges Project to conduct a concrete analysis of specific conditions. Zhang Ruijin the analysis of the situation and Gezhouba project concludes that “hydrostatic off ships, moving water will sand” measures are based on the following three objective