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 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.

Test Studyed of Yangjiawan Grand Bridge in the Project of Lanyu Railway by Movable Bed Model

2012 ◽  
Vol 204-208 ◽  
pp. 2070-2073
Author(s):  
Wen She He ◽  
Long Yuan ◽  
Shuang Mei Chang ◽  
Jing Jing Feng ◽  
Liang Ming Wang
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Flow Direction ◽  
Bridge Site ◽  
Design Data ◽  
Lanzhou City ◽  
Bed Topography ◽  
River Bed ◽  
Before And After ◽  
Movable Bed

Yangjiawan grand bridge is located in Lanzhou section of the Yellow River. In order to study the change laws near the bridge site of flow direction, velocity distribution, water surface slope, backwater area, river bed topography change and the effect of flood control on Lanzhou city after the bridge-built when the river gets through the average discharge, 20-year discharge, and 100-year discharge before and after the bridge-built. Based on the similar principle of model, the river near the bridge site was simulated by the hydraulic model experiment of movable bed. The result of experiment showed that the design data adopted in bridge project of Yangjiawan grand bridge were reasonable and fulfilled the requirements of city flood control. It was also suggested to excavate and dredge river near the piers of 6# ~11# and strengthen embankment near the riverbank and protection of constructions after the bridge-built.

scholarly journals Evolution process of different abnormal river bends in the braided reach of the Lower Yellow River

2020 ◽  
Vol 32 (6) ◽  
pp. 1837-1847
Author(s):  
JIANG Qingrong ◽  
◽  
XIA Junqiang ◽  
ZHOU Meirong ◽  
WANG Yingzhen
Keyword(s):  
Yellow River ◽  
Evolution Process ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
River Bends ◽  
Braided Reach

Experimental Research on Preventing Root-Stones Loss with Tetrahedron-Like Concrete Penetrating Frames

2011 ◽  
Vol 233-235 ◽  
pp. 1930-1934
Author(s):  
Jie Shi ◽  
Xiao Lei Zhang ◽  
Zun Xin Huang
Keyword(s):  
Water Flow ◽  
Experimental Research ◽  
Flood Control ◽  
Yellow River ◽  
The Yellow River ◽  
Direct Impact ◽  
The Lower Yellow River ◽  
Scour Holes ◽  
Protection Technology ◽  
Flood Diversion

The root-stones loss for flood control project is serious in the Lower Yellow River, and the tetrahedron-like concrete penetrating frame is a new protection technology. The Experiment on preventing root-stones loss of flood diversion and regulation works in Taohuayu with tetrahedron-like concrete penetrating frames in the Xingyang reach of the Yellow River. The experiment results show that: (1) the technology of tetrahedron-like concrete penetrating frame is simple, and it can make root-stones very steady; (2) the tetrahedron-like concrete penetrating frame can effectively reduce the depth of scour holes in front of dam and slow the direct impact of water flow on the dam body; (3) the tetrahedron-like concrete penetrating frame can effectively reduce root-stones loss and save lots of stones; (4) the tetrahedron-like concrete penetrating frames could be made use of for the project foundation stabilization, and they are thrown into the slope of root-stones and the riverbed outside slope toe within a certain width to increase the effect of root-stones protection better.

scholarly journals Prediction of sediment concentration based on the MEEMD-ARIMA model in the lower Yellow River

2019 ◽  
Vol 11 (4) ◽  
pp. 1570-1579
Author(s):  
Xianqi Zhang ◽  
Fei Liu ◽  
Chao Song ◽  
Xiaoyan Wu
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Moving Average ◽  
Arima Model ◽  
Sediment Concentration ◽  
Lower Yellow River ◽  
Autoregressive Integrated Moving Average ◽  
The Lower Yellow River ◽  
Frequency Domains ◽  
Annual Sediment

Abstract There are many factors influencing the evolution of sediment concentration, and it is difficult to determine and extract, which brings great difficulties to the high-precision prediction of sediment concentration. Accurate prediction of annual sediment concentration in the lower Yellow River can provide a theoretical basis for flood control and disaster reduction and rational utilization of water and soil resources in the lower Yellow River. For the defects of pseudo-components in data decomposition of Complementary EEMD, the Modified EEMD (MEEMD) method proposed in this paper has the advantage of eliminating pseudo components of IMF and reducing non-stationarity of sediment bearing sequences. Then, combined with the Autoregressive Integrated Moving Average (ARIMA) model with strong approximation ability to the stationary sequence, the MEEMD-ARIMA model for predicting the annual sediment concentration in the lower Yellow River was constructed. Through fitting and predicting the annual sediment concentration in Gaocun Station, it is shown that the model not only considers the evolution of sediment concentration in various frequency domains, but also solves the problem that the ARIMA model requires sequence to be stable, the relative error of prediction is within ±6%, and the prediction accuracy is high, thus providing a new method for the prediction of sediment concentration.

scholarly journals Research on the periodic regularity of annual runoff in the Lower Yellow River

2018 ◽  
Vol 10 (1) ◽  
pp. 130-141 ◽  
Author(s):  
Xianqi Zhang ◽  
Chao Song ◽  
Dengkui Hu
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Annual Runoff ◽  
Entropy Spectrum ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Multi Scale ◽  
Runoff Series ◽  
Maximum Entropy Spectrum ◽  
Main Period

Abstract Research on the periodic characteristics of the runoff evolution in the Lower Yellow River is of great importance for flood control, beach regulation and water resources utilization in the Lower Yellow River. By using wavelets to conduct scale analysis of runoff series, the periodic change rule of runoff series on different scales can be obtained. By using the maximum entropy spectrum to analyze the spectrum of runoff, the main period of runoff sequence can be obtained. In this paper, these two methods are applied to the annual runoff of the Lower Yellow River. The results show that: the annual runoff in the Lower Yellow River has multi-scale change law; the four stations have the same main period; there are differences in periodicity between stations, as the catchment area increases, the quasi-periodic value decreases, and the periodic fluctuation becomes more obvious; after 2018, the annual runoff of the Lower Yellow River will be in the dry season. Furthermore, the study can reveal the change law of runoff sequence in the Lower Yellow River to a certain extent, and provide a theoretical basis for river management.

Study on Drag Reduction of Suspended Flow with Extra Fine Sediment

2010 ◽  
Vol 439-440 ◽  
pp. 1567-1571
Author(s):  
Chang Jun Zhu
Keyword(s):  
Drag Reduction ◽  
Water Level ◽  
Flood Control ◽  
Yellow River ◽  
Reduction Rate ◽  
Fine Sediment ◽  
Flood Peak ◽  
The Lower Yellow River ◽  
Abnormal Phenomenon ◽  
Xiaolangdi Reservoir

In view of the abnormal phenomenon that a flood peak increased in August 2004 and July 2005 along the lower Yellow River, the mechanism of this abnormal phenomenon is studied. It is found that the flood increase was due to the decrease the channel roughness in the propagation of high concentrated flood carrying the extra fine sediment which was discharged from xiaolangdi reservoir. In view of this, the equation of drag reduction rate is derivated under variable k pattern, and is applied to the reality. The results show that the equation is reliable and has important role in flood control and calculation in water level with hyperconcentration flow. The study of this paper only is a try and discuusion, and need to be improved.

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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