关键词: 河床冲淤, 水面线, 一维水沙数学模型, 雅口航运枢纽, 碾盘山枢纽

Abstract: After the completion of Danjiangkou Reservoir dam heightening and the operation of Middle Route Project of South-to-North Water Diversion, the discharge-sediment condition in the middle-lower reach of the Hanjiang River changed, meanwhile the cascade reservoirs construction will further change river boundary condition. Taking Yakou-Nianpanshan section in the middle reach of the Hanjiang River as an example, one-dimensional flow-sediment mathematical model is employed to study the influence of cascade reservoirs operation on riverbed evolution and water surface profile. The results indicate that the operation of Yakou hydro-junction leads to downstream riverbed erosion before the construction of Nianpanshan hydro-junction, and the water surface line is lowered accordingly. After the completion of Nianpanshan hydro-junction, the riverbed evolution is characterized by overall silting except near-dam reach slight scouring, which leads to the rising of water level. The research can provide scientific basis for the design and demonstration of hydro-junction project, waterway regulation and flood control project.

Key words: riverbed erosion and siltation, water surface profile, one-dimensional flow and sediment mathematical model, Yakou hydro-junction, Nianpanshan hydro-junction