Keywords: 
• bathymetric change /
• deposition rate /
• accretion and erosion /
• Yangtze subaqueous delta

Abstract: How the topography of the Yangtze subaqueous delta has evolved in response to sediment decline has aroused wide attention. In order to examine the Yangtze subaqueous delta evolution and influencing factors during the past six decades, bathymetric data surveyed in eight different years during the period of 1958-2015 covering more than 7 000 km² of the subaqueous delta in the Yangtze River Estuary were analyzed together with the river sediment dataset of the same period using Surfer software. The results show that the overall morphological evolution of subaqueous delta in the Yangtze River Estuary went through three phases:sedimentation, equilibrium, and intense fluctuation. The decline in sediment had led to net erosion in areas with depth less than 10 m since 2009. Sharp decline in sediment supply and sediments transported from the outer estuary induced by extreme whether are the two important reasons for the dramatic change in the erosion and deposition of the subaqueous delta in the Yangtze River Estuary in recent years. The annual sediment delivered from the Yangtze River Estuary to the open seas is likely to be less than 120 million tons in the past decades, which is almost equivalent to the sediment load in recent years, indicating that the entire subaqueous delta in the Yangtze River Estuary may gradually reach equilibrium state through internal adjustment in the future.