INTER-DECADAL VARIATIONS IN SURFACE SEDIMENT DISTRIBUTION PATTERNS OFF THE RECENTLY ABANDONED HUANGHE RIVER MOUTH AND THEIR KEY CONTROLLING FACTORS

Inter-decadal variations in surface sediment distribution patterns off the recently abandoned Huanghe river mouth were studied based on the grain-size data of the surface sediment. Combined with the data of bathymetry and hydrodynamics off the abandoned river mouth, the key factors that control the temporal variations were discussed. The results indicate that the surface sediment off the recently abandoned Huanghe river mouth display a seaward fining trend at an inter-decadal scale. The mean grain size (Mz, in Φ unit) of surface sediment reached its highest level in 1992. It was coarsening up from 1992 to 2000. During the period of 2000—2007, the sediment off the recently abandoned river mouth became coarser, while the surface sediments remained unchanged during the period of 2007—2015 in the study area. The variation of surface sediment is both controlled by hydrodynamics and erosion-deposition patterns of the study area. The spatial distribution of surface sediment almost kept stable with the increase in erosion resistance off the recently abandoned river mouth.