Title
Sediment fluxes within salt marsh tidal creek systems in the Yangtze Estuary
Author
Sun, J. (TU Delft Coastal Engineering; East China Normal University)
van Prooijen, Bram (TU Delft Coastal Engineering) 
Wang, Xianye (East China Normal University)
Zhao, Zhonghao (East China Normal University)
He, Qing (East China Normal University)
Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)
Date
2024
Abstract
Creeks are essential for salt marshes by conveying water and sediment through this geomorphic system. In this paper, we investigate the mechanisms that determine the residual sediment flux using measurements conducted in tidal creeks in salt marshes of the Yangtze Estuary. A main creek and a secondary creek were studied to explore whether the mechanisms determining residual sediment fluxes through the main creek differ from those in the secondary creek. Measurements in creeks were carried out over 5 years, spanning different months. Sediment import was found during most tides, both in the main creek and the secondary creek, implying that creeks in Chongming generally function as a conveyor belt of sediment into the marsh. However, sediment export can occur during certain overbank tides. When comparing the role of creeks in drainage and sediment delivery, the main creek functions more in delivering sediment while the secondary creek primarily serves as a drainage conduit. To better understand the mechanisms behind sediment fluxes, the residual sediment flux was compared with the residual discharge and the sediment differential (differences in sediment concentration between flood and ebb). Overbank tides generally lead to a net outward discharge as more water from saltmarshes can be concentrated into the marsh creek during ebb tides. This net outward discharge tends to export more sediment during ebb tides. However, due to the sediment abundance during the flood phase in the turbid environment, sediment import can be expected even with the residual export of water. Export of sediment was only found for the few tides with a net outward discharge and a small positive sediment concentration differential. Large negative sediment differentials (larger averaged suspended sediment concentration during ebb tides) have not been observed because the sediment supply during ebb is limited. This paper unravels how the sediment differential and residual discharge contribute to the residual sediment flux, providing a better understanding of sediment dynamics in marsh creek systems.
Subject
Marsh creek systems
Sediment availability
Sediment flux
To reference this document use:
http://resolver.tudelft.nl/uuid:b2ef9acd-9738-431d-a368-a0069ddf756d
DOI
https://doi.org/10.1016/j.geomorph.2023.109031
Embargo date
2024-07-04
ISSN
0169-555X
Source
Geomorphology, 449
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2024 J. Sun, Bram van Prooijen, Xianye Wang, Zhonghao Zhao, Qing He, Zhengbing Wang