Journal ArticleDOI
Bed shear stress estimation on an open intertidal flat using in situ measurements
TLDR
In this paper, the authors used high-frequency in situ measurements of water depths and near-bed velocities to estimate bed shear stress on an open intertidal flat in the Yangtze Delta, China.Abstract:
Accurate estimations for the bed shear stress are essential to predict the erosion and deposition processes in estuaries and coasts. This study used high-frequency in situ measurements of water depths and near-bed velocities to estimate bed shear stress on an open intertidal flat in the Yangtze Delta, China. To determine the current-induced bed shear stress (τc) the in situ near-bed velocities were first decomposed from the turbulent velocity into separate wave orbital velocities using two approaches: a moving average (MA) and energy spectrum analysis (ESA). τc was then calculated and evaluated using the log-profile (LP), turbulent kinetic energy (TKE), modified TKE (TKEw), Reynolds stress (RS), and inertial dissipation (ID) methods. Wave-induced bed shear stress (τw) was estimated using classic linear wave theory. The total bed shear stress (τcw) was determined based on the Grant–Madsen wave–current interaction model (WCI). The results demonstrate that when the ratio of significant wave height to water depth (Hs/h) is greater than 0.25, τcw is significantly overestimated because the vertical velocity fluctuations are contaminated by the surface waves generated by high winds. In addition, wind enhances the total bed shear stress as a result of the increases in both τw and τc generated by the greater wave height and reinforcing of vertical turbulence, respectively. From a comparison of these various methods, the TKEw method associated with ESA decomposition was found to be the best approach because: (1) this method generates the highest mean index of agreement; (2) it uses vertical velocities that are less affected by Doppler noise; and (3) it is less sensitive to the near-bed stratification structure and uncertainty in bed location and roughness.read more
Citations
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Journal ArticleDOI
Erosion potential of the Yangtze Delta under sediment starvation and climate change.
Haifei Yang,Haifei Yang,Shilun Yang,Kehui Xu,Hui Wu,Benwei Shi,Benwei Shi,Q. Zhu,Q. Zhu,W. X. Zhang,Zhen Yang +10 more
TL;DR: It is expected that the Yangtze subaqueous delta will experience continuous erosion under sediment starvation and climate change in the next decades of this century or even a few centuries.
Journal ArticleDOI
Bed-level changes on intertidal wetland in response to waves and tides: A case study from the Yangtze River Delta
TL;DR: In this paper, the authors combined in situ measurements with model simulations to quantify short-term bed-level changes on a meso-macrotidal wetland in the Yangtze River Delta.
Journal ArticleDOI
Sediment transport and fluid mud layer formation in the macro-tidal Chikugo river estuary during a fortnightly tidal cycle
TL;DR: In this paper, the erosion and deposition dynamics of fine sediment in a highly turbid estuarine channel were successfully surveyed during the period from August 29 to September 12, 2009 using an echo sounder and a high-resolution acoustic Doppler current profiler.
Journal ArticleDOI
Patterns and drivers of daily bed-level dynamics on two tidal flats with contrasting wave exposure.
TL;DR: New insights are provided in the pattern and drivers of daily intertidal bed-level dynamics, thereby setting a template for future high-resolution field monitoring programmes and inviting in-depth morphodynamic modelling for improved understanding and predictive capability.
Journal ArticleDOI
River-sea transitions of sediment dynamics: A case study of the tide-impacted Yangtze River estuary
TL;DR: In this article, the authors investigated sediment dynamic transitions in a 660 km long section between the tidal limit and mouth of the Yangtze River, and established a conceptual model of the river-sea transition of sediment dynamics for sediment dynamics in other large tide-dominated estuaries worldwide.
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