scholarly journals Influence of Floodplain Flooding on Channel Siltation Adjustment under the Effect of Vegetation on a Meandering Riverine Beach

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1402
Author(s):  
Li Junhua ◽  
Zhang Mingwu ◽  
Jiang Enhui ◽  
Pan Li ◽  
Wang Aoxue ◽  
...  
Keyword(s):  
Model Test ◽  
Flood Control ◽  
Yellow River ◽  
Main Channel ◽  
Experimental Simulation ◽  
Theoretical Research ◽  
Main Stream ◽  
Compound Channel ◽  
Water And Sediment ◽  
Beach Vegetation

Flooding in a sediment-laden floodplain is affected by riverine beach vegetation and the shape of a meandering compound channel. The laws of water and sediment exchange and the deposition distribution in beach troughs are very complex. These factors play a significant role in the formation and development of secondary suspended rivers, in the adjustment of the beach horizontal gradient, and even in the evolution of the flood control situation. In this study, we used a combination of experimental simulation and theoretical research to carry out a generalized model test of floodplain flooding evolution, analyzed the lateral distribution characteristics of sediment-laden flow and sediment factors in a meandering compound channel under the conditions of beach vegetation, and revealed the pros and cons of beach vegetation on the adjustment of the beach and channel siltation. The model test results of the flooding in the floodplain in the compound channel with meandering vegetation showed that the main stream was not only concentrated in the main channel but also appeared near the foot of the left and right bank levees and formed flood discharges along the embankment. As the riverine beach siltation was mainly concentrated at the riverine beach lip, the vegetation on the riverine beach had a significant effect on slowing down the flow velocity. Whether it was a row or full vegetation on both sides of the bank, this played an important role in the stability of the main channel. When there was no vegetation on the riverine beach, the main channel was easy to move. The arrangement of full vegetation on the riverine beach had a uniform effect on the velocity distribution of the riverine beach, which reduced the phenomenon of excessive velocity at the foot of the riverine beach and increased the velocity effect in the main channel. These results will provide a theoretical basis for the utilization of riverine beach areas and river management in the lower Yellow River and have a great significance for enriching the basic theory of water and sediment movement and promoting the integration of hydraulics, river dynamics, and ecology.

scholarly journals Study on the Horizontal Distribution Law of Flood Water and Sediment Factors under the Effect of Vegetation on a Curved Beach

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1441
Author(s):  
Mingwu Zhang ◽  
Pan Li ◽  
Xiaoping Li ◽  
Aoxue Wang ◽  
Zhenhai Wang ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Model Test ◽  
Main Channel ◽  
Theoretical Research ◽  
Distribution Model ◽  
Main Stream ◽  
Compound Channel ◽  
Transverse Distribution ◽  
Water And Sediment ◽  
Beach Vegetation

The sediment-laden floodplain flood is affected by beach vegetation and the shape of curved compound channels. The laws of water and sediment exchange and deposition distribution in beach troughs are very complex and play a significant role in the formation and development of secondary suspended rivers, the adjustment of beach horizontal gradients, and even the evolution of flood control situations. This study used a combination of experimental simulations and theoretical research to carry out a generalized model test of floodplain flood evolution, analyzing the transverse distribution characteristics of sediment-laden flow and sediment factors in a curved compound channel under the conditions of beach vegetation, proposing a theoretical model of transverse distribution of velocity and sediment concentration that is based on the momentum equation considering the inertial force of the lateral secondary flow and river curvature. The results showed the following: (1) The model test results for floodplain flood in the compound channel with curved vegetation showed that the main stream was not only concentrated in the main channel but also appeared near the foot of the left and right bank levees and formed flood discharge along the embankment, as the beach siltation was mainly concentrated in the beach lip; (2) The arrangement of full vegetation on the beach had a uniform effect on the velocity distribution of the beach, which can reduce the phenomenon of excessive velocity at the foot of the beach and increase the velocity effect in the main channel; and (3) Through five numerical examples, the lateral velocity distribution model of a curved compound channel with beach vegetation was tested and, in general, the analysis model was consistent with the experimental results. The research results will provide a theoretical basis for river management and have great significance for enriching the basic theory of water and sediment movement and promoting the integration of hydraulics, river dynamics, and ecology.

The Capability Analysis of Flood Discharge in Ningmeng of Yellow River

2012 ◽  
Vol 212-213 ◽  
pp. 705-709
Author(s):  
Xin Ai Jing ◽  
Xiu Zhi Lin ◽  
Su Zhen Hou ◽  
Gen Li Liu
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Main Channel ◽  
Water Level Rise ◽  
Flow Duration ◽  
Bankfull Discharge ◽  
Water And Sediment ◽  
Capability Analysis ◽  
Small Flow ◽  
Control Decision

the amount of water and sediment reduce obviously in Ning Meng reach because of the influence of the regulation of Long-Liu reservoir in upper of Yellow River、rainfall and production and living use water, especially the time reduce of large flows and the growth of small flow duration time, resulting main channel siltation and atrophy severe in the Inner Mongolia Reach, lower bankfull discharge, the main channel flooding capacity decreased when the great flood of water level rise, resulting in the increase of the river's ice flood control pressure. The study will provide technical support for flood control decision-making.

Research on the Numerical Simulation of Silting in Floodplain and Scouting in Main Channel of Over-Bank Flooding in the Lower Yellow River

2011 ◽  
Vol 255-260 ◽  
pp. 3692-3696
Author(s):  
Xiao Lei Zhang ◽  
Dong Po Sun ◽  
Feng Ran Zhang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Yellow River ◽  
Main Channel ◽  
River Channel ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Water And Sediment ◽  
Simulation Results ◽  
Set Up

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.

scholarly journals Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China

2018 ◽  
Vol 246 ◽  
pp. 01019
Author(s):  
Tao Li ◽  
Jun-hua Zhang ◽  
Guoming Gao ◽  
Huaibao Ma
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Deposition Process ◽  
Utilization Efficiency ◽  
Comprehensive Utilization ◽  
Water And Sediment ◽  
River Bed ◽  
Main River ◽  
Effective Use ◽  
Xiaolangdi Reservoir

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river.

scholarly journals Response Relationship between the Upward or Downward Moving Distance of Main Stream Zone and Water and Sediment Conditions in Wandering Channels

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3610
Author(s):  
Linjuan Xu ◽  
Lianjun Zhao ◽  
Enhui Jiang ◽  
Junhua Li ◽  
Meng Chen
Keyword(s):  
Flood Control ◽  
Quantitative Relationship ◽  
Scientific Basis ◽  
Main Stream ◽  
Response Relationship ◽  
Small Water ◽  
Regime Stability ◽  
Water And Sediment ◽  
The Stability ◽  
The Way

The change of water and sediment conditions in wandering channels has a great impact on the stability of river regime. The quantitative relationship between them is still unclear. The qualitative influence of water and sediment conditions on the river regime stability was analyzed by a model test. The response relationship between the upward or downward moving distance of the main stream zone and water and sediment conditions was quantitatively studied by using the measured water and sediment data and large-section data over the years. The results showed that when the upstream water and sediment inflow conditions change, the stability of a wandering channel with relatively stable river regime under the control of finite boundary will still change. When the river channel is at 1000 m3/s under the action of long-term small water, or silting thickness is about 0.53 m, the main stream next to the project moves upwards about 1170 m along the way. In the case of a large flood, such as 8000 m3/s, or scouring depth is about 0.39 m, the main stream next to the project moves downwards about 870 m along the way. The study provides a certain scientific basis for river regime stability and river flood control early warning, and provides a certain method reference for quantitative study of river regime evolution of other rivers at home and abroad.

scholarly journals Research Progress on Causes and natural cut-off of distorted river bends

2018 ◽  
Vol 246 ◽  
pp. 01095
Author(s):  
ZHAO Wanjie ◽  
XU Linjuan ◽  
LI Junhua ◽  
WANG Yuanjian ◽  
JIANG Enhui
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Research Progress ◽  
Main Stream ◽  
Control Engineering ◽  
The Lower Yellow River ◽  
River Bed ◽  
Plane Shape ◽  
River Bends ◽  
Important Position

In recent years, the distorted river bends occurs frequently in the lower reaches of the Yellow River, and the critical catastrophe occurs of natural cut-off under the action of flood scouring during flood season, which directly affects the plane shape of the river channel and the flood control safety of local reach. By collecting a large number of literature and combining existing research results, the causes of the deformed rivers and the natural cutting phenomenon are reviewed. The formation of the distorted river bends is mainly related to the incompatibility of the upstream water and sediment inflow conditions with the river boundary conditions, the formation of local anti-scour nodes (such as clay mouth) and the emergence or control engineering, and the different anti-scour properties of the riverbed leading to the main stream swing. In the development and evolution process of river bays, natural cutting curve occupies an important position, and there are three typical forms, such as erosion ditch type, bank collapsing type and die cutting type, and its cutting ratio is 1.6-6.9. In the future, we should study the composition of the river bed, study the causes and mechanism of the abnormal river regime in the lower Yellow River more deeply, predict the trend of the abnormal river regime scientifically, and evaluate the damage.

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

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 357 ◽  
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.

Analysis of Inflow Design Flood for Liujiaxia Reservoir under Dynamic Operation of Flood Limited Water Level for Ten-Day Period

2012 ◽  
Vol 212-213 ◽  
pp. 725-730
Author(s):  
Ji Qing Li ◽  
Di Shen ◽  
Ai Jing Wang ◽  
Yu Shan Zhang
Keyword(s):  
Water Level ◽  
Flood Control ◽  
Yellow River ◽  
Main Stream ◽  
Design Flood ◽  
Joint Operation ◽  
Cascade Hydropower Stations ◽  
Storage Area ◽  
Hydropower Stations ◽  
Flood Limited Water Level

the layout and the characteristics of the cascade reservoirs and hydropower stations in the upper reaches of the Yellow River, determine that cascade hydropower stations scheduling must be operated based on the joint operation between Longyangxia and Liujiaxia cascade hydropower stations, especially on flood control operation. This paper deeply analyzes design flood storage area of the Liujiaxia composition and Longyangxia-Liujiaxia joint flood regulating principle on the basis of analyzing and calculating each ten-day design flood of the Tangnaihai above main stream and the intervals. Therefore, the reasonable combination of interval flood and the process of Longyangxia reservoir flood discharge is confirmed, and thereby, studying Liujiaxia reservoir inflowing design flood under a controlling operation of flood limited water level for a period of ten-day to ensure the safety of Liujiaxia reservoir flood control.

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