Process-based morphodynamic modeling of a schematized mudflat dominated by a long-shore tidal current at the Central Jiangsu Coast, China

摘要

Gong, Z.; Wang, Z.B.; Stive, M.J.F.; Zhang, C.K., and Chu, A., 2012. Process-based morphodynamic modeling of a schematized mudflat dominated by a long-shore tidal current at the central Jiangsu coast, China. This paper focuses on the process-based morphodynamic modeling of a mudflat dominated by a long-shore tidal current. The model is schematized as a shore-parallel tidal basin with dimensions similar to the tidal flats near the Wanggang Mouth at the central Jiangsu coast, China. A long-shore tidal current and associated sediment transport are dominant in comparison with their cross-shore components. The mudflat evolution is reproduced for both the case with abundant sediment supply and that with insufficient sediment supply. The simulated flow patterns agree qualitatively with field observations from literature, i.e., involving tidal asymmetry, current directions, and tidal wave features. The analysis of sediment fluxes depicts that deposition occurs from spring tide to neap tide and erosion from neap tide to spring tide. The results show that siltation on intertidal flats is favored by flood dominance, as well as settling and scour lag effects, with less dependence on sediment supply. However, subtidal flats are strongly affected by sediment supply. The simulated double-convex cross-shore profile associated with an abundant sediment supply is qualitatively consistent with field observations. An insufficient sediment supply causes erosion and consequent widening of the subtidal flats. Finally, the practical case with an initial sand seabed is reproduced. The long-shore sediment transport contributes to long-shore variations of cross-shore profiles. Deposition rates increase clearly southward in the area between the lower intertidal and middle subtidal flats when sediment supply is abundant. In contrast, deposition rates increase southward only slightly when sediment supply is insufficient. In addition, stronger sediment supply generates wider intertidal flats. Most importantly, the creek patterns, i.e., the incised creeks on mudflats, are roughly reproduced.