Suspended sediment concentration and deformation of riverbed in a frazil jammed reach

2000 ◽  
Vol 27 (6) ◽  
pp. 1120-1129 ◽  
Author(s):  
Jueyi Sui ◽  
Desheng Wang ◽  
Bryan W Karney
Keyword(s):  
Sediment Transport ◽  
Open Channel ◽  
Field Experiments ◽  
Suspended Sediment Concentration ◽  
Yellow River ◽  
Sediment Concentration ◽  
Ice Jams ◽  
Frazil Ice ◽  
Ice Jam ◽  
Load Sediment

The presence of ice in rivers affects hydrodynamic conditions through changes in both the river's boundary conditions and its thermal regime. Therefore, the characteristics of sediment transport and the deformation of the river channel in ice-covered rivers are quite different from those experiencing conventional open channel flow. The variables of ice behavior, ice jamming extent, sediment transport, and deformation of the riverbed during ice periods are interrelated on the basis of both physical arguments and field experiments of river ice jams in the Hequ Reach of the Yellow River. The characteristics of sediment concentration in water, frazil ice, and ice cover are described. Analyses have been made on the mechanism of the evolution of frazil jam and the associated adjustments in the riverbed. It has been found that the evolution of the ice jam and the deformation of the riverbed reinforce each other. The interrelationship between the particular features of evolution of ice jam and deformation of riverbed is summarized here in the form of regression relationships relating the hydraulic parameters of water under ice jams to the deformation-extent of the riverbed and the jamming-extent.Key words: deformation of riverbed, evolution of frazil jam, frazil jam, suspended load, sediment concentration.

scholarly journals Freeze-Up Ice Jam Formation in the River Bend, a Case Study on the Inner Mongolia Reach of Yellow River

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 631
Author(s):  
Shui-Xia Zhao ◽  
Wen-Jun Wang ◽  
Xiao-Hong Shi ◽  
Sheng-Nan Zhao ◽  
Ying-Jie Wu ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Yellow River ◽  
Open Water ◽  
River Ice ◽  
Freezing Process ◽  
Ice Jams ◽  
Narrow Channels ◽  
Frazil Ice ◽  
Ice Jam ◽  
Bed Changes

Concern has been expressed regarding the impacts of climate change on river ice and ice jam formation in cold regions. Ice jams are easily initiated in bends and narrow channels and cause disasters. In this study, observations and remote sensing monitoring are used to study the freeze-up ice jam formation of bends. Sediment transport and freezing process of the river interact, influencing bed changes profile and sedimentary budget. River ice processes, channel evolution, ice hydro-thermodynamics, and ice jam accumulation are explored. The results show that the channel topography determines the river thalweg, and that the channel elevation interacts with the river ice through sediment transport. The channel shrinkage increases the probability of ice jam, and the sharp bend is prone to ice jam formation. Under the effect of secondary circulation flow in the bend and in the outer bank, the juxtaposed freeze-up and the hummocky ice cover occur in the same location, and frazil ice accumulates under the junction of the main channel and the shoals. Affected by the increase of the hydraulic slope and the velocity downstream, open water reaches develops downstream of the ice accumulation. An open water section is emerged upstream of the bend, due to the ice deposition, and partly cut-off supply of the frazil.

scholarly journals Transport Mechanism of Suspended Sediments and Migration Trends of Sediments in the Central Hangzhou Bay

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2189
Author(s):  
Zekun Song ◽  
Weiyong Shi ◽  
Junbiao Zhang ◽  
Hao Hu ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Hangzhou Bay ◽  
The South ◽  
Transport Mode ◽  
Tidal Pumping ◽  
The North

Based on the 2013 field survey data of hydrology, suspended sediments and bottom sediments in the Central Hangzhou Bay, this paper explores the dynamic mechanism of suspended sediments in Hangzhou Bay by employing material flux decomposition. Meanwhile, the migration trends of bed sediments are also investigated by analyzing grain size trends. The results show that during an ebb or flood tide, the hydrograph of suspended sediment concentration of Hangzhou Bay is dominated by an M shape (bimodal), which is attributed primarily to the generation of a soft mud layer and a separate fluid mud layer. Laterally, the distribution of suspended sediment concentration is high in the south and low in the north. From a macroscopic perspective, the net sediment transport in the study area displays a “north-landward and south-seaward” trend, presenting a “C”-shaped transport mode. That is, the sediments are transported from the bay mouth to the bay head on the north side and from the bay head to the bay mouth on the south side. The sediment transports by advection and tidal pumping are predominant, while the sediment transport by vertical circulation makes little contribution to the total sediment transport. Moreover, the sediment transport in the center of the reach area is dominated by advection, whereas that near both sides of the banks is controlled by tidal pumping. The asymmetry of the tides, i.e., flood-dominance in the north and ebb-dominance in the south, is the primary cause of the dynamic mechanism for the overall “C”-shaped transport mode in Hangzhou Bay. Additionally, coupled with the narrow-head wide-mouth geomorphology, Hangzhou Bay remains evolving by south shore silting and north shore scouring.

scholarly journals Sediment Transport During an Outburst from Glacier De Tsidjiore Nouve, Switzerland, 16–19 June 1981

1983 ◽  
Vol 29 (101) ◽  
pp. 185-190 ◽  
Author(s):  
Ian Beecroft
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Bed Load ◽  
Stream Discharge ◽  
Large Water

AbstractBetween 16 and 19 June 1981 a large water pocket of volume 183 000 m3 burst from glacier de Tsidjiore Nouve. From hourly stream discharge and suspended sediment concentration observations a suspended sediment output of 1 674 × 103 kg was calculated. The transport of bed-load was estimated at 3 840 × 103 kg, hence a total quantity of around 5 500 × 103 kg of sediment were removed from the catchment, including the pro-glacial field, in the four days of the outburst.

Laboratory Study on the Relationships Between Suspended Sediment Concentration and Electrical Conductivity

2009 ◽  
Author(s):  
Qian Dai ◽  
Hongxian Shan ◽  
Yonggang Jia ◽  
Xiangmei Meng ◽  
Honglei Li ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Yellow River ◽  
Influencing Factor ◽  
Yellow River Delta ◽  
Sediment Concentration ◽  
Conductivity Sensor ◽  
Linear Relationships ◽  
High Turbidity

In order to find a simple, continuous method to determine the suspended sediment concentration in a high turbidity region, experiments were conducted to look for relationships between suspended sediment concentration and electrical conductivity. Sediments were sampled from the Yellow River Delta and a conductivity sensor was used to measure the electrical conductivity of different sediment content seawater. The influencing factors such as temperature and salinity are also investigated. The results show that good linear relationships exist between suspended sediment concentration and electrical conductivity; salinity and temperature have some influence on electrical conductivity, and salinity is the most important influencing factor and temperature takes the second place. Basically, the general linear regression formulas between suspended sediment concentration and electrical conductivity can be drawn with variable salinity and temperature. The relationships suggest that it is feasible to measure suspended sediment concentration in situ using electrical conductivity sensors.

scholarly journals Periodic Oscillation of Sediment Transport Influenced by Winter Synoptic Events, Bohai Strait, China

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 986 ◽  
Author(s):  
Haiqin Duan ◽  
Jingping Xu ◽  
Xiao Wu ◽  
Houjie Wang ◽  
Zhiqiang Liu ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Yellow Sea ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Northerly Wind ◽  
Wind Event ◽  
Bohai Strait

Instruments on two bottom-mount platforms deployed in the Bohai Strait during a cruise from January 6–13, 2018 recorded an intense northerly wind event. The responses of hydrodynamic and hydrographical characteristics in Bohai Sea and Yellow Sea to the wind event were analyzed aided by the wind, wave, sea surface suspended sediment concentration and sea surface height datasets from open sources. It is shown that the strong wind event had a significant impact on the redistribution of sea surface height, regional wave conditions, regional circulations and the accompanying sediment transport pattern. Specifically, the sediment transport through the Bohai Strait may be divided into two chronological phases related to the wind event: (1) the enhanced sediment transport phase during the buildup and peak of the wind event when both the Northern Shandong Coastal Current and regional suspended sediment concentration were sharply increased; and (2) the relaxation phase when the northerly wind subsided or even reversed, accompanied by the enhanced Yellow Sea Warm Current with lowered suspended sediment concentration. Such results at synoptic scale would improve our capability of quantifying sediment exchange between the Bohai and Yellow sea, through the Bohai Strait and provide valuable reference for the study of other similar environments worldwide.

scholarly journals Emergent stationarity in Yellow River sediment transport and the underlying shift of dominance: from streamflow to vegetation

2019 ◽  
Vol 23 (1) ◽  
pp. 549-556 ◽  
Author(s):  
Sheng Ye ◽  
Qihua Ran ◽  
Xudong Fu ◽  
Chunhong Hu ◽  
Guangqian Wang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Yellow River ◽  
Yellow River Basin ◽  
Sediment Concentration ◽  
Topographic Characteristics ◽  
The Yellow River Basin ◽  
Annual Scale ◽  
Annual Discharge

Abstract. Soil erosion and sediment transport play important roles in terrestrial landscape evolution and biogeochemical cycles of nutrients and contaminants. Although discharge is considered to be a controlling factor in sediment transport, its correlation with sediment concentration varies across the Yellow River basin (YRB) and is not fully understood. This paper provides analysis from gauges across the YRB covering a range of climates, topographic characteristics, and degrees of human intervention. Our results show that discharge control on sediment transport is dampened at gauges with large mean annual discharge, where sediment concentration becomes more and more stable. This emergent stationarity can be attributed to vegetation resistance. Our analysis shows that sediment concentration follows a bell shape with vegetation index (normalized difference vegetation index, NDVI) at an annual scale despite heterogeneity in climate and landscape. We obtain the counterintuitive result that, as mean annual discharge increases, the dominant control on sediment transport shifts from streamflow erosion to vegetation retardation in the YRB.

scholarly journals WAVE-INDUCED FLOW AND NEARSHORE SUSPENDED SEDIMENT

1988 ◽  
Vol 1 (21) ◽  
pp. 108 ◽  
Author(s):  
J.C. Doering ◽  
A.J. Bowen
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Accurate Prediction ◽  
Wave Crest ◽  
Wave Trough ◽  
Induced Flow ◽  
Wave Induced ◽  
Velocity Skewness

It has been realized for nearly one hundred years that the transport of sediment is related to the characteristics of a wave, in particular its shape. Cornish (1898) noticed that the shoreward velocity associated with a wave crest was more effective at moving coarse sediment than was the seaward velocity associated with the wave trough. Cornish's observation was consistent with the theory of Stokes (1847), which predicts the onshore velocity associated with the wave crest is stronger and of shorter duration than the offshore velocity associated with the wave trough. This horizontal asymmetry of the cross-shore flow, which is a reflection of the wave shape, is known as velocity skewness. It has been suggested that "the existence of the beach depends on small departures from symmetry in the velocity field balancing the tendency for gravity to move material offshore"(Bowen, 1980). Although the concept of velocity skewness has been incorporated into detailed predictors of sediment transport (Bowen, 1980; Bailard and Inman, 1981) it is only one of many facets that needs to be understood in order to make the accurate prediction of sediment transport realizable. A comprehension of sediment transport is hampered by both an incomplete knowledge of the hydrodynamics and a lack of instrumentation to directly measure instantaneous sediment concentration and the accurate prediction of sediment transport is probably the most enigmatic problem in coastal engineering. Occasionally, suspended sediment concentration has been inferred from in situ pumps and hand-held tubes, but these methods lack the temporal and spatial resolution necessary to elucidate the details of the interaction between the waveinduced flow and the sediment. Recently, a miniature optical backscatter sensor (MOBS), which provides a time series of suspended sediment concentration at a "point", was developed by Downing et al. (1981). During a recent field experiment a vertical array of 5 of these optical backscatter sensors and a colocated flow meter was deployed close to the sea bed. These colocated measurements provide a unique opportunity to investigate the response of near-bed suspended sediment concentration to the wave-induced flow.

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