VARIATION IN SEDIMENT LOAD AND GRAIN-SIZE UNDER THE INFLUENCE OF WATER AND SEDIMENT REGULATION SCHEME (WSRS) OF THE HUANGHE (YELLOW) RIVER

Based on the data of hydrology and sediment from 1950-2013, the variation of the Huanghe sediment under the influence of the Water and Sediment Regulation Scheme (WSRS) is investigated. The result indicates that, after the WSRS, the flow regime is characterized by a stable and constant high level of water and sediment discharge from June to November. The regime before the WSRS, which was characterized by a sharp peak from July to October, disappeared. It means that the seasonal characteristics are noticeably changed under the influence of the WSRS. Along with the implementations of WSRS, the river bed sediments in the lower reaches are increasingly coarser than ever, resulting in the continuous increase in the critical energy for sediment resuspension. During the period of WSRS, however, the peak value of water discharge remains constant, the erosion rate in the lower reaches slows down. The direct result for this variation is that the annual sediment load from the Huanghe to the sea gradually decreases together with the decreasing grain size. Thus, the accretion rate outside the Huanghe estuarine mouth will decrease and the critical sediment discharge to maintain the equilibrium of the active Huanghe delta lobe will increase in the coming years.