Modeling the shore-normal profile shape evolution for an accretional tidal flat on the central Jiangsu coast

The evolution of the shore-normal profile shape of an accretional tidal flat is controlled by the transport of muddy and sandy sediments by tidal currents. To understand the evolution processes, a model is established to simulate the tidal flat profile changes in response to spring-neap tidal cycles, and it is applied to the accretional tidal flat on the central Jiangsu coast to investigate the interrelationships between the initial profile shape of the inter-tidal flat, tidal range, sediment supply, the equilibrium profile shape of the intertidal flat, and the long-term behavior of a prograding profile. The modeling output indicates that: (1) the shape of the accretional tidal flat tends to be convex when reaching its equilibrium state; (2) equilibrium of the intertidal flat morphology is independent of the initial profile shape; (3) if the sediment supply remains stable, then the width of the intertidal flat is positively correlated to tidal range; (4) the width of the intertidal flat increases with sediment supply and the accretion or erosion status of the intertidal flat is determined by sediment supply; (5) there is a need to design an algorithm to treat the area close to high water on springs to simulate long-term growth of the tidal flat; (6) the intertidal flat associated with abundant sediment supply will progradeg towards the sea, and at the same time its equilibrium shape will be maintained; and (7) the width and gradient of the intertidal flat from the model output are consistent with those of the Jiangsu coast, when inputting parameters derived locally for the model.