Cross-Shore Sediment Transport on an Open Tidal Flat: Wind-Driven Flow Reversal and Fluid Mud

Abstract

Understanding sediment transport processes within tidal flats is crucial for developing effective land-ocean interaction management strategies. The cross-shore sediment transport on tidal flats induced by episodic events, such as wind-driven flow reversal (WDFR) and fluid mud (FM), is not sufficiently understood. This study focuses on the central Jiangsu tidal flat, where two field campaigns were conducted in the winter of 2021 and the summer of 2022. During the winter campaign, WDFR events were identified. During WDFR, the wind reversed the tide flow direction, resulting in significant cross-shore sediment fluxes. In summer, FM occurred frequently during tidal slack periods when current-induced bottom stress was low. The settling of sediment from the overlying fluid into the bottom layer plays a pivotal role in initiating FM events. These events resulted in substantial cross-shore sediment fluxes, exceeding the long-shore component. This study highlights the need to appropriately address the contributions of WDFR and FM to cross-shore sediment transport in similar coastal environments.