Study on Key Technology of Xiaolangdi Reservoir Operation for Flood Control and Sediment Reduction during the Late Sediment-retaining Period

摘要

This paper conducts a comprehensive and deeply analysis and research on key technology of Xiaolangdi Reservoir operation for flood control and sediment reduction during the late sediment-retaining period by theoretical study,filed survey,observed data analysis,mathematical model analysis and physical model tests etc.Based on the study of flow and sediment movement laws in the reservoir during the late sedimentretaining period and characteristics of sediment transport and channel evolution along the lower Yellow River,combining of scheme calculation and analysis,the paper presents regulation indexes of the reservoir such as regulatory and control discharge and duration,regulatory and control capacity,and time to scour by lowering operation water level etc.The paper mainly studies two operation modes for sediment reduction,one of which is"raising water level gradually and retaining coarse sediment and discharging fine sediment" and another is "to regulate sediment for many years and seek chances to scour by lowering operation water level,retaining sediment and adjusting water and sediment",and the paper has studied operational mode for flood control.The paper has conducted analysis and research on different schemes from flood control effect of the reservoir,medium flood control,reservoir sedimentation,the sediment flushing effect,extension of useful life of reservoir sediment capacity,the effect on sediment reduction in the lower River and median water river bed maintaining with the reservoir,benefit of power generation and water supply etc.The paper presents the operation mode and dispatching principle for flood control and sediment reduction during the late sedimentretaining period,with the core idea which is "to regulate sediment for many years and seek chances to scour by lowering operation water level,retaining sediment and regulating water and sediment,".The operation mode for flood control and sediment reduction has the following characteristics: flexibility of reservoir operation,great adaptability with incoming water and sediment condition,long service life of sediment capacity,with great sediment reduction effect in the lower river,and significantly modifying the contradiction of flood control in the lower flood plain.