The analysis on the characteristic of sediment delivery in Aishan-Lijin section shows that: a) The river-bed evolution at narrow section downstream of Aishan has the basic characteristics of as a major flood and deposition as its small and sand is scoured and coarse ones deposited and deposition including coarse, medium-sized and fine sand is mainly happened in non-flood season. In flood season, the medium-sized and fine sand are all washed away except the deposition of coarse sand. b) The scouring and deposition in Aishan-Lijin section are mainly related with discharge. According to the flood data from 1960 to 2002 and analysis on critical discharge for scouring and deposition of coarse, medium-sized and fine sands, the paper establishes a relationship between sediment delivery rate of different particle sizes and discharge of Aishan-Lijin section and initially establishes a relational expression between critical sediment concentration and discharge of Aishan Station under the conditions of no deposition happened in Aishan-Lijin section during flood season after considering the factors of flood routing and water and sediment diversion of the reach.
