CHARACTERISTICS OF SEDIMENT TRANSPORT ALONG A RIVER REACH WITH A RESERVOIR

Based on long-term measurements at three gauging stations,Toudaoguai,Fugu and Hequ,and one meteorological station,this article discusses the features of discharge (Q) and sediment concentration (CS) of a river reach of the Yellow River with a reservoir located in the Loess Plateau. The impacts of the local sub-watershed between Toudaoguai and Fugu gauging stations on sediment budget to the Yellow River have been analyzed. In addition,the deposition processes in the Tianqiao Reservoir have been investigated. Results show over 80% of the precipitation that falls in the local sub- watershed is unable to contribute to the Yellow River runoff process. It is found that the annual maximum sediment concentration is usually less than 30 kg/m3 during flood seasons at Toudaoguai Gauging Station,but the sediment concentration varies dramatically at Fugu Gauging Station. About 35% of the sediment eroded in the sub-watersheds between Toudaoguai and Fugu gauging stations was produced from the Huangfuchuan sub-watershed which has a drainage area accounting only for 10% of the drainage area between Toudaoguai and Fugu gauging stations. The Tianqiao Reservoir generally has deposition during the summer flood season,and scouring during the non-flood season. On average,over 85% of deposited sediment in the reservoir occurs in the 12 km long lower reservoir reach. The volume of annual deposition in the reservoir mainly depends on the volume of water from the local region between Hequ and Fugu gauging stations.