Shaping and maintaining a medium-sized main channel in the Lower Yellow River

The 2-D water and sediment mathematical model which reflects silting in floodplain and scouting in main channel of over-bank flooding in the Lower Yellow River has been set up in this paper. Through carrying on 2-D water and sediment numerical simulation of the “96.8” typical flood, the author studied influence of over-bank flooding on flood travel and transverse exchange. The primary simulation results show that, adopting the over-bank flooding for silting in floodplain and scouting in main channel effectively guaranteed and expanded transverse exchange between floodplain and main channel and maintained the river channel vigor. This can relieve “secondary suspended river” states in the Low Yellow River to a certain extent; at the same time, the different magnitudes of over-bank floods have different effect of silting in floodplain and scouting in main channel.

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Response of channel geometry to flow and sediment conditions in the lower Yellow River

10.5194/egusphere-egu2020-5274 ◽

2020 ◽

Author(s):

Huan Jing ◽

Deyu Zhong ◽

Hongwu Zhang

Keyword(s):

Yellow River ◽

Management Strategies ◽

Sediment Concentration ◽

Main Channel ◽

Channel Stability ◽

Cross Sectional ◽

Channel Geometry ◽

Lower Yellow River ◽

The Lower Yellow River ◽

Erosion Intensity

The channel geometry in a fluvial river is significantly affected by the flow and sediment regimes, and the response behavior of channel dimensions usually varies widely to different management strategies from the upstream reservoir. Therefore, it is significantly crucial to investigate the variation of the channel geometry in response to changing flow and sediment conditions and quantify the influence of the latter in the sedimentation reduction and flood releasing in lower reaches downstream of the dam. In this study, three laboratory experiments on the physical model covering the typical braided reach HGK&#8212;JHT downstream of the Xiaolangdi Reservoir in the lower Yellow River are carried out, under the discharge of 2000 m3/s, 3000 m3/s, and 4000 m3/s respectively and with the corresponding constant suspended sediment concentration of 8.0 kg/m3. Results indicate that (i) spatially, the erosion and deposition in studied channel reach distributed alternately along the course which performs typical evolution properties of the braided river, corresponding to the total erosion amount of 2.27&#215;106 m3, 10.29&#215;106 m3, and 7.98&#215;106 m3 for three magnitude of discharges; and (ii) four representative adjustment patterns are listed based on the observed cross-sectional geometry after each experiment, including the lateral widening pattern, vertical incision pattern, composite pattern and geometrical stable pattern where sectional geometry rarely changes during the period of experiment; and (iii) the quantity &#958;=B1/2/H where B and H is the width and depth of the main channel zone is selected as the typical indicator to determine the variation of the channel stability. It is discovered that &#958; in the reaches upstream of section FJS have rather larger values, implying relatively wider and shallower sectional geometry and lower channel stability which is closely associated with the levee safety. And moreover, the quantity &#958; generally has lower values, that is, higher channel stability with the increase of experiment discharge; Besides, through the method of nonlinear regression analysis, the empirical relations for HGK&#8212;JHT Reach are developed between the main channel dimensions and incoming flow erosion intensity F=(Q2/S)/106 where Q is the discharge and S is the corresponding sediment concentration. In general, the calculated results are generally consistent with the measured values, as the riverbed degradation and the variation of sectional area increase exponentially with a stronger erosion intensity F.This paper may provide some practical basis for the study of channel evolution in sediment-laden rivers.

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Response of Erosion and Deposition of Channel Bed, Banks and Floodplains to Water and Sediment Changes in the Lower Yellow River, China

Water ◽

10.3390/w11020357 ◽

2019 ◽

Vol 11 (2) ◽

pp. 357 ◽

Cited By ~ 1

Author(s):

Xiaofei Liu ◽

Changxing Shi ◽

Yuanyuan Zhou ◽

Zhenkui Gu ◽

Huijuan Li

Keyword(s):

Yellow River ◽

Water Discharge ◽

Sediment Concentration ◽

Main Channel ◽

River Channel ◽

Lower Yellow River ◽

Main Research ◽

The Lower Yellow River ◽

Water And Sediment ◽

Geomorphic Units

River channel change can be very sensitive to environmental change and human activities and it has been one of the main research topics in fluvial geomorphology. In this study, repeated channel geometric measurements were used to investigate the channel adjustment to water and sediment changes of the lower Yellow River in China in the past few decades. With a high sediment concentration and large variations of water discharge, the lower Yellow River has a much active channel in its form and location, which has hindered previous research efforts to study long-term differentiated erosion/deposition of different geomorphic units in the channel. In this study, we divided each of four typical channel across-sections at hydrological stations in the lower Yellow River into different units according to the geomorphological features, and give a detailed investigation of erosion/deposition processes of these geomorphic units and the interactions between them besides the influence of incoming water and sediment conditions. The results show that with a significant decreasing trend of both the annual runoff and sediment load of the river and abrupt changes in 1985–1996, the overall siltation trend in the river channel before 1990 had been replaced by a slight erosion trend after 2006. In the earlier period, the siltation in the upstream wandering and transitional reaches mainly occurred on floodplains and that in the downstream straight reaches principally on main channel bed. In the later period, erosion occurred mainly on high and low bank slopes in the wandering reaches and on main channel bed in the transitional reaches. The erosion became weak in the wandering reaches after 2010, continued in the transitional reaches, and was still relatively minor in the straight reaches, reflecting the downstream hysteresis channel response to changes in water and sediment discharges down dams. Our results suggest that the seasonal erosion/deposition of a geomorphic unit of the river channel can be attributed to the changes in water and sediment discharges as well as to the interaction between geomorphic units. Siltation on the main channel bed could be attributed to erosion on the bank slopes in both the sections in the wandering and transitional reaches, and erosion of the main channel bed in flood seasons was negatively related with the mean water discharge at the two sections in the straight reaches. This result implies that fixing the bank slopes in the wandering and transitional reaches and raising the water discharge in the straight reach in flood seasons are favorable options for controlling the development of the two-level perching channel of the lower Yellow River.

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Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

Journal of Geographical Sciences ◽

10.1007/s11442-020-1738-3 ◽

2020 ◽

Vol 30 (3) ◽

pp. 468-487 ◽

Cited By ~ 2

Author(s):

Yanjun Wang ◽

Baosheng Wu ◽

Deyu Zhong

Keyword(s):

Yellow River ◽

Main Channel ◽

Channel Geometry ◽

Lower Yellow River ◽

The Lower Yellow River ◽

Before And After ◽

Xiaolangdi Reservoir

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MODEL FOR LOSS ASSESSMENT DUE TO FLOOD IN THE LOWER YELLOW RIVER

Environmental Engineering and Management Journal ◽

10.30638/eemj.2015.207 ◽

2015 ◽

Vol 14 (8) ◽

pp. 1933-1939

Author(s):

Xianqi Zhang ◽

Weiwei Han ◽

Xiaofei Peng ◽

Cundong Xu

Keyword(s):

Yellow River ◽

Loss Assessment ◽

Lower Yellow River ◽

The Lower Yellow River

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Simulating cross-sectional geometry of the main channel in response to changes in water and sediment in Lower Yellow River

Journal of Geographical Sciences ◽

10.1007/s11442-020-1826-4 ◽

2020 ◽

Vol 30 (12) ◽

pp. 2033-2052

Author(s):

Yanjun Wang ◽

Baosheng Wu ◽

Deyu Zhong

Keyword(s):

Yellow River ◽

Main Channel ◽

Cross Sectional ◽

Lower Yellow River ◽

Water And Sediment

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High-Arsenic Groundwater in Paleochannels of the Lower Yellow River, China: Distribution and Genesis Mechanisms

Water ◽

10.3390/w13030338 ◽

2021 ◽

Vol 13 (3) ◽

pp. 338

Author(s):

Chuanshun Zhi ◽

Wengeng Cao ◽

Zhen Wang ◽

Zeyan Li

Keyword(s):

Yellow River ◽

The Yellow River ◽

Rock Interaction ◽

Lower Yellow River ◽

The Lower Yellow River ◽

Groundwater Samples ◽

Groundwater Systems ◽

Different Sources ◽

High Arsenic ◽

High Arsenic Groundwater

High–arsenic (As) groundwater poses a serious threat to human health. The upper and middle reaches of the Yellow River are well–known areas for the enrichment of high–arsenic groundwater. However, little is known about the distribution characteristics and formation mechanism of high-As groundwater in the lower reach of the Yellow River. There were 203 groundwater samples collected in different groundwater systems of the lower Yellow River for the exploration of its hydrogeochemical characteristics. Results showed that more than 20% of the samples have arsenic concentrations exceeding 10 μg/L. The high-As groundwater was mainly distributed in Late Pleistocene–Holocene aquifers, and the As concentrations in the paleochannels systems (C2 and C4) were significantly higher than that of the paleointerfluve system (C3) and modern Yellow River affected system (C5). The high-As groundwater is characterized by high Fe2+ and NH4+ and low Eh and NO3−, indicating that reductive dissolution of the As–bearing iron oxides is probably the main cause of As release. The arsenic concentrations strikingly showed an increasing tendency as the HCO3− proportion increases, suggesting that HCO3− competitive adsorption may facilitate As mobilization, too. In addition, a Gibbs diagram showed that the evaporation of groundwater could be another significant hydrogeochemical processes, except for the water–rock interaction in the study area. Different sources of aquifer medium and sedimentary structure may be the main reasons for the significant zonation of the As spatial distribution in the lower Yellow River.

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