Sediment discharging effect through density current of Xiaolangdi Reservoir and the response of the Lower Yellow River

Based on the observed data in years from 2000 to 2006,the erosion and deposition in Xiaolangdi Reservoir area and the Lower Yellow River have been analyzed.Under persistent scouring state,the relationship between sediment carrying capacity and accumulative erosion has been quantified according to sediment transport law.It is pointed that the reason of the decrease of sediment transport capacity is the inadequate supplement of fine and medium sized sediment(less than 0.05mm) within effective bed exchange layers.With reference to the observed data during the period of Sanmenxia Reservoir impoundment,the sediment discharging effect through density current floods of Xiaolangdi Reservoir and the response of the Lower Yellow River have been compared and studied.Xiaolangdi Reservoir provids a great potential for detaining coarse and releasing fine sediment.It is found that hyperconcentrated density current floods would not result in severe deposition in the Lower Yellow River.Therefore,it is possible to fully use the natural or artificial density currents to discharge more sediment and realize the sedimentation reduction of the Lower Yellow River for a long time.