Print Email Facebook Twitter Sand‐Mud Tidal Flat Morphodynamics Influenced by Alongshore Tidal Currents Title Sand‐Mud Tidal Flat Morphodynamics Influenced by Alongshore Tidal Currents Author Wang, Yunwei (Hohai University) Wang, Yaping (East China Normal University) Yu, Qian (Nanjing University) Du, Zhiyun (Nanjing University) Wang, Zhengbing (TU Delft Coastal Engineering; Deltares) Gao, Shu (East China Normal University) Date 2019 Abstract Tidal flats, where significant land‐ocean interactions take place, are often abstracted as a cross‐shore bed profile with sediment zonation from the lower sand flat to the upper mud flat. However, in addition to cross‐shore tidal currents, the impact of the alongshore components on cross‐shore sediment transport, morphological evolution, and sediment grain‐size change remains unclear. Here we investigated sand‐mud tidal flat morphodynamics in the absence of waves by combining approaches of field observations, numerical modeling, and analytical interpretations, based on the example of the tidal flat on the central Jiangsu coast, China. The results show that the morphodynamic processes are complicated by the interactions of cross‐shore and alongshore tidal currents, cross‐shore flat morphology, and sediment zonation. With amplified phase lags of the alongshore tidal level at the boundaries, alongshore currents become dominant over cross‐shore tidal currents on the lower flat, while the upper flat is always dominated by the cross‐shore currents. Therefore, bed profiles and mud content on the upper flat were independent of the alongshore tidal current magnitude, being convex‐up and consisting of mud. In contrast, the strong alongshore currents can erode mud on the lower flat and promote landward sand transport from the subtidal area to the lower flat, forming a sand flat. The maximum tidal bed shear stress is almost spatially uniform across the muddy area but pronouncedly elevated where the bed sediment coarsens on the lower flat. The contributions of the alongshore tidal currents and sand‐mud sorting processes should be appropriately addressed in similar coastal environments. To reference this document use: http://resolver.tudelft.nl/uuid:4b5e8a18-fed4-4070-a78b-7d817a0d2781 DOI https://doi.org/10.1029/2018JC014550 ISSN 2169-9275 Source Journal Of Geophysical Research-Oceans, 124 (6), 3818-3836 Bibliographical note Accepted Author Manuscript Part of collection Institutional Repository Document type journal article Rights © 2019 Yunwei Wang, Yaping Wang, Qian Yu, Zhiyun Du, Zhengbing Wang, Shu Gao Files PDF 839085_1_merged_1550319606_1_.pdf 8.17 MB Close viewer /islandora/object/uuid:4b5e8a18-fed4-4070-a78b-7d817a0d2781/datastream/OBJ/view