Storm-induced hydrodynamic changes and seabed erosion in the littoral area of Yellow River Delta: A model-guided mechanism study

Fan, Yaoshen; Chen, Shenliang; Pan, Shunqi; Dou, Shentang

doi:10.1016/j.csr.2020.104171

Cited by 32 publications

(27 citation statements)

References 54 publications

(49 reference statements)

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“…This demonstrates that wave-induced shear stress is the main contributor to total bed shear stress during large gales. This means that waves generate sufficient shear stress to resuspend sediment, which is consistent with previous studies with remote sensing (Chu et al, 2006;Zhang et al, 2018;Li et al, 2021), field investigations (Yang et al, 2011;Liu et al, 2020;Niu et al, 2020;Zhang et al, 2021), and numerical simulations (Jiang et al, 2004;Fan et al, 2020).…”

Section: Sediment Resuspensionsupporting

confidence: 91%

Field observations of seabed scour dynamics in front of a seawall during winter gales

Sun

Xu²,

Zhang³

et al. 2022

Front. Mar. Sci.

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Seawalls are vital for protecting coastal areas. However, the seabed in front of seawalls may undergo severe scouring. This can result in destabilization of the seawall structure, the underlying mechanisms of which remains unclear. Therefore, an integrated observation system consisting of acoustic and optical instruments was deployed in areas with severe seabed scouring. This observation system was used to observe sediment dynamics elements such as waves, currents, tides, turbulence and suspended sediment concentration (SSC) for 31 days in winter. Using advanced time–frequency analysis techniques including wavelet transform and spectrum analysis, we examined the dynamic factors associated with sediment resuspension and transport. In calm weather conditions, a notable increase in SSC was not observed indicating that the tidal dynamics were not sufficient for sediment suspension. During high winds, the SSC increased sharply to 12,222 mg/L, and the sediment vertical diffusion flux induced by turbulence was coupled to SSC, indicating that the increased SSC was predominantly attributed to local resuspension. Consistent temporal distribution of turbulence-induced sediment vertical diffusion flux and momentum flux in high wavelet power spectra highlights the important role of turbulence in sediment dynamics. Enhanced longshore currents during high wave conditions intensified sediment transportation. Horizontal net sediment fluxes notably increased to 769 t/m2 per day during winter gales, which had a significant effect on seabed erosion. This study reveals the key processes associated with seabed scouring in front of seawalls during gale events.

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Section: Sediment Resuspensionsupporting

confidence: 91%

Field observations of seabed scour dynamics in front of a seawall during winter gales

Sun

Xu²,

Zhang³

et al. 2022

Front. Mar. Sci.

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“…The sediment erosion parameters and other parameters are initially selected based on a similar study (Fan, 2019). The parameters are set as follows: sediment particle size of 0.05 mm, sediment density of 1600 kg/m 3 , sediment settling velocity of 0.15 mm/s, erosion rate of 5×10 -4 m 2 /s, critical initial stress of 0.115 N/ m 2 , and porosity of 0.5.…”

Section: Model Setupmentioning

confidence: 99%

Numerical study of the water-sediment regulation scheme (WSRS) impact on suspended sediment transport in the Yellow River Estuary

Jia

2023

Front. Mar. Sci.

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IntroductionThe transport of suspended sediment plays an important role in regulating erosion-accretion in estuaries. The Yellow River, the second longest river in China, which has a large amount of sediment and contributes sediment to the Yellow River Estuary (YRE) every year. The water and sediment discharge patterns in the lower reaches of the Yellow River have experienced significant changes over recent decades. In particular, the water-sediment regulation scheme (WSRS) of the Xiaolangdi Reservoir transports large amounts of water and sediment to the YRE within a very short time, causing dramatic changes in the spatiotemporal estuarine sediment dynamics.MethodsIn this study, we presented a coupled numerical model based on FVCOM-SWAVE-SED that considered the highly dynamic sediment variations in the YRE. The sediment distribution and erosion-accretion patterns in the YRE during the WSRS in 2013 were analyzed by the high-resolution model.ResultsThe sediment entering the YRE spread with freshwater, forming a high sediment concentration zone near the river mouth, where most of the sediments were deposited. The sediment dispersal distance was limited by the tidal shear frontal (TSF), and the southeast outspread length of the sediment was slightly larger than the northwest spread. Outside of the YRE, the areas with high flow currents exhibited high erosion. We examined the effects of the main external driving forces (such as waves, tides, and runoff) on the sediment distribution and showed that runoff, tides, and waves were the key factors affecting the sediment distribution of the YRE.ResultsThis study shows that WSRS effectively changes the sediment distribution and erosion condition in the YRE and provides a data for researches on changes in estuarine ecosystems.

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“…Strong storm surges prevailed around the Bohai Sea during the past 2000 years (Feng, 1982;Liu, 1989). Based on the observing hydrodynamic and sediment data, the simulation results of an abandoned Yellow River Delta lobe, revealed that local storms enhanced tidal residual currents and considerably weakened tidal shear front, intensified the sediment resuspension and dispersal (Fan et al, 2020). Under storm conditions, surface suspended sediment concentration was 2 times as large as that in normal conditions.…”

Section: Major Geomorphic Processes and A Model Of The Evolution Of T...mentioning

confidence: 99%

Geomorphologic evolution of the shallow-buried abandoned Yellow River delta during the last 2000 years

et al. 2022

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Different from the continuous development of many river deltas since the major Holocene transgression, the modern Yellow River delta (YRD) remained for nearly 1000 years (from 893 AD to 1855 AD) in an abandonment state, until after 1855 AD when it was buried after the Yellow River entered the sea via Lijin. In this study we used optically stimulated luminescence (OSL) dating and grain size and sedimentary facies analysis of four borehole cores, combined with an analysis of landform morphology, to reconstruct the history of the ancient abandoned YRD. The results indicate that after the delta was abandoned due to the reduced sediment supply by the Yellow River in 893 AD, a sandy coast developed under the influence of wave erosion, and offshore shell ridges were formed beyond the coastline. During the interval from the Medieval Warm Period (MWP) to the Little Ice Age (LIA), driven by climate change and storm surges, the shell ridges migrated laterally, widened and rose, while sediment accumulation in the landward-side interfluvial floodplains was relatively weak. This configuration subsequently constituted a coastal highland – plain depression system. After 1077 AD, this system, together with the abandoned delta, was eroded by the Daqing River estuary. After 1855 AD, the abandoned delta landform system was completely buried by Yellow River sediments, and the wave-controlled sandy coast was transformed to a tide-controlled silt-mud coast. We summarize these findings in the form of a geomorphic model of the evolution of the abandoned delta from the MWP to the LIA. Overall, our results highlight the geomorphic effects of the sediment-laden river delta and the response of the abandoned delta geomorphic system on the millennial timescale, and they provide a theoretical foundation for predicting the geomorphic evolution of a major river delta on different timescales, against the background of global change.

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Storm-induced hydrodynamic changes and seabed erosion in the littoral area of Yellow River Delta: A model-guided mechanism study

Abstract: induced hydrodynamic changes and seabed erosion in the littoral area of Yellow River Delta: A model-guided mechanism study,

Cited by 32 publications

References 54 publications

Field observations of seabed scour dynamics in front of a seawall during winter gales

Field observations of seabed scour dynamics in front of a seawall during winter gales

Numerical study of the water-sediment regulation scheme (WSRS) impact on suspended sediment transport in the Yellow River Estuary

Geomorphologic evolution of the shallow-buried abandoned Yellow River delta during the last 2000 years

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