Sediment discharge by floods of Yellow River without stressing on blocking coarse particles and releasing fine particles

The results of research on sediment transport in Yellow River in China were briefly described.It is concluded that floods with a sediment concentration of higher than 200 kg/m3 are suitable for sediment discharge,and that characteristics of sediment transport in narrow and deep channels of lower Yellow River result in a mechanism of the more sediment input, more sediment output.When flow velocity in a river with low sediment concentration reaches 1.8-2.0 m/s,the river bed surface will be in a dynamic adjusting status,and coarse particles(d0.025 mm) will follow same rule.Sediment regulation in Xiaolangdi Reservoir is making full use of flood potential in lower river channel for sediment discharge into lower Yellow River.In normal flow years and dry years,the total volume of flood water is used for water conservancy and environmental protection,while in wet years,floods with high sediment concentration can be used for sediment discharge.It is also unnecessary to block coarse particles and release fine particles in sediment discharge.