Flooding sedimentation at the Yellow River mouth, China

Chinese Huanghe (Yellow River) provides an extreme case of human controlled large river system. Since 2002, a unique Water-Sediment Regulation (WSR) regime was implemented annually through Xiaolangdi Dam to buffer pool infilling and scour the hanging riverbed. This involves transfers of large-volume of water and sediment between reservoirs, becoming a human-made flooding event. 37 surface sediments 8 box cores sampled during the 2018 WSR were analyzed for grain-size, C/N, 13C, radionuclides, etc. Satellite images together with high-resolution bathymetric data were incorporated to depict the flooding sedimentation at the river mouth. The results show that 7Be and 210Pb activity is pretty low, implying its incapability of tracing flood sediments at the Huanghe River mouth. The results also uncover that a majority of the sediment was deposited in the vicinity of the river mouth where the water depth is less than 15 m. Two depocenters with a maximum thickness of 9 m were formed expanding within a very restricted area, which was largely controlled by tidal currents.