Study Of Sediment Deposition In Reservoirs With Sinking Streams

This paper proposes a one-dimensional mathematical model to calculate the situation that open channel flow and pressure conduit flow alternately appears.This model is a one-dimensional model with unsteady open channel flow and unsteady pipe flow coupled.Besides,experimental research has been explored in this paper to learn the impacts of the pressurized pipe on the sediment deposition of the reservoir with sinking streams.The experimental results were compared to the calculation results to verify the reliability of the presented mathematical model.Generalized topography was adopted in the mathematical model to simulate the sediment deposition of the reservoir with sinking streams,where the influences on the sedimentation caused by sinking streams were presented.Furthermore,by comparing the sediment deposition status under different hydraulic conditions and different arrangements of the sinking streams,impacts of these elements were studied.A flume experiment was conducted and the impacts of the pipe was analyzed as well.The main contents and results of this paper are as follows:(I)The principle of the one dimensional mathematical model which coupled free surface flow and pressurized flow was introduced,and the calculated results were verified by comparing with the flume experimental results.(II)In the one dimensional mathematical model,generalized topography was adopted to simulate the reservoir with two sinking streams.The calculated results include the pondage,accumulative amount of sediment and the deposition morphology.Also,by changing hydraulic conditions and arrangements of sinking streams,their impacts on the sediment deposition were studied,which includes the water level,accumulative amount of sediment,the deposition morphology and sediment delivery ratio.(III)A flume experiment was conducted,where the aggradation was recorded to explore the sedimentation rules.Similarly,by changing hydraulic conditions such as discharge and tail water level to learn their impacts on the reservoir sedimentation.(IV)Differences between the model and practical engineering were analyzed,and improvement suggestions were proposed.Besides,suggestions about the operation of reservoirs with sinking streams are provided.