Discussion on the Mechanism of the Differences of Sediment Transport Capability of the Different Alluvial Reaches in the Yellow River

According to the principles of hydraulics,fluvial processes study and river sediment dynamics, the authors discuss the mechanism of different capabilities of sediment transport of different alluvial reaches in the Yellow River. The results are: the main reason of low sediment transport capability in Ningmeng Reach is weak hydrodynamic power, the narrow and deep cross-section profile determines the high sediment tranport capability and the frequent hyper- concentrated floods during which the sediment settling velocity reduced by the increasing of hydro-viscosity and density resulting from high sediment concrentration also improve the capabiliity of sediment transort in the Lower Weihe, in the Lower Yellow River the strong hydrodynamic power is the most important factor conducing the high sediment transport capability, for the Xiaobeiganliu reach though the hydro-dynamic power is strong the big particle size of suspended sediments reduces the sediment transport capability.