Estuarine morphodynamic adaptation to sediment supply and human activities

Abstract

Estuarine morphodynamics undergo significant changes due to declined sediment supply from river, rising sea-level, and human interferences (Syvitski and Saito, 2007; Syvitski et al., 2009). The Yangtze Estuary is such a case whose decadal morphodynamic evolution was broadly examined. It was documented that the subaqueous delta shifted from deposition to erosion since the early 2000s due to sediment supply reduction after the Three Gorges Dam (Yang et al., 2015) while some others reported that the estuary mouth bar area sustains accretion until 2010 (Luan et al., 2016; Zhu et al., 2016). The mouth bar area of the Yangtze Estuary is where the turbidity maximum exists. To clarify the morphodynamic changes therein, we examine the two large scale shoals, i.e. the Hengsha flat and the Jiuduan shoal, based on bathymetric data between 1958 and 2016 and satellite images since 1985.