scholarly journals Characterizing and identifying bedforms in the wandering reach of the lower Yellow River

2021 ◽  
Author(s):  
Yuanfeng Zhang ◽  
Ping Wang ◽  
Guanqing Shen
Keyword(s):  
Yellow River ◽  
Lower Yellow River ◽  
The Lower Yellow River

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

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

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

Water ◽  
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.

Does actual cropland water consumption change with evaporation potential in the Lower Yellow River?

2021 ◽  
Vol 316 ◽  
pp. 107468
Author(s):  
Zhigang Sun ◽  
Shiji Li ◽  
Kangying Zhu ◽  
Ting Yang ◽  
Changxiu Shao
Keyword(s):  
Water Consumption ◽  
Yellow River ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Consumption Change

Variation in reach-scale thalweg-migration intensity in a braided reach of the lower Yellow River in 1986-2015

2017 ◽  
Vol 42 (13) ◽  
pp. 1952-1962 ◽  
Author(s):  
Jie Li ◽  
Junqiang Xia ◽  
Meirong Zhou ◽  
Shanshan Deng ◽  
Xiaolei Zhang
Keyword(s):  
Yellow River ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Migration Intensity ◽  
Braided Reach

Sediment load and storage in the lower yellow river during the late holocene

2010 ◽  
Vol 92 (3) ◽  
pp. 297-309 ◽  
Author(s):  
Changxing Shi ◽  
Luan Zhang ◽  
Jiaqiang Xu ◽  
Lipeng Guo
Keyword(s):  
Late Holocene ◽  
Sediment Load ◽  
Yellow River ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
And Storage

scholarly journals Spatial Expansion of Human Settlement during the Longshan Period (~4.5–~3.9 ka BP) and Its Hydroclimatic Contexts in the Lower Yellow River Floodplain, Eastern China

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 712
Author(s):  
Kaifeng Li ◽  
Wenhua Gao ◽  
Li Wu ◽  
Hainan Hu ◽  
Panpan Gong ◽  
...  
Keyword(s):  
Yellow River ◽  
Asian Summer Monsoon ◽  
Spatial Expansion ◽  
Human Settlement ◽  
Human Settlements ◽  
Lower Yellow River ◽  
River Floodplain ◽  
The Lower Yellow River ◽  
Asian Summer ◽  
Longshan Period

Obvious spatial expansion of human settlement occurred in the lower Yellow River floodplain during the Longshan period, but the external factors driving this expansion remain unclear. In this study, we first delineated the hydroclimatic changes at both regional and local scales within and around the lower Yellow River floodplain and then examined the relationships of human settlements with hydroclimatic settings between the pre-Longshan and Longshan periods. The results indicate that the site distribution, site density and hydroclimatic conditions exhibited significant shifts during the pre-Longshan and Longshan periods. In the pre-Longshan period, the intense East Asian summer monsoon and abundant monsoon-related precipitation caused widespread development of lakes and marshes in the lower Yellow River floodplain. As a result, the circumjacent highlands of the lower Yellow River floodplain contained concentrated human settlements. However, the persistent weakening of the East Asian summer monsoon and consequent precipitation decline, in conjunction with accelerated soil erosion due to decreasing forest vegetation and strengthening of human activities on the upstream Loess Plateau in the Longshan period, are likely to have jointly caused both shrinking and faster filling of preexisting lakes and marshes. Subsequently, a large area of arable land had been created in the lower Yellow River floodplain and thus was occupied by locally rapid increasing population, resulting in the notable spatial expansion of human settlements during the Longshan period.

scholarly journals Morphodynamic model of the lower Yellow River: flux or entrainment form for sediment mass conservation?

2018 ◽  
Vol 6 (4) ◽  
pp. 989-1010 ◽  
Author(s):  
Chenge An ◽  
Andrew J. Moodie ◽  
Hongbo Ma ◽  
Xudong Fu ◽  
Yuanfeng Zhang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Yellow River ◽  
Mass Conservation ◽  
Transport Rate ◽  
Entrainment Rate ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Fine Grained ◽  
Sediment Transport Rate ◽  
Sediment Mass

Abstract. Sediment mass conservation is a key factor that constrains river morphodynamic processes. In most models of river morphodynamics, sediment mass conservation is described by the Exner equation, which may take various forms depending on the problem in question. One of the most widely used forms of the Exner equation is the flux-based formulation, in which the conservation of bed material is related to the stream-wise gradient of the sediment transport rate. An alternative form of the Exner equation, however, is the entrainment-based formulation, in which the conservation of bed material is related to the difference between the entrainment rate of bed sediment into suspension and the deposition rate of suspended sediment onto the bed. Here we represent the flux form in terms of the local capacity sediment transport rate and the entrainment form in terms of the local capacity entrainment rate. In the flux form, sediment transport is a function of local hydraulic conditions. However, the entrainment form does not require this constraint: only the rate of entrainment into suspension is in local equilibrium with hydraulic conditions, and the sediment transport rate itself may lag in space and time behind the changing flow conditions. In modeling the fine-grained lower Yellow River, it is usual to treat sediment conservation in terms of an entrainment (nonequilibrium) form rather than a flux (equilibrium) form, in consideration of the condition that fine-grained sediment may be entrained at one place but deposited only at some distant location downstream. However, the differences in prediction between the two formulations have not been comprehensively studied to date. Here we study this problem by comparing the results predicted by both the flux form and the entrainment form of the Exner equation under conditions simplified from the lower Yellow River (i.e., a significant reduction of sediment supply after the closure of the Xiaolangdi Dam). We use a one-dimensional morphodynamic model and sediment transport equations specifically adapted for the lower Yellow River. We find that in a treatment of a 200 km reach using a single characteristic bed sediment size, there is little difference between the two forms since the corresponding adaptation length is relatively small. However, a consideration of sediment mixtures shows that the two forms give very different patterns of grain sorting: clear kinematic waves occur in the flux form but are diffused out in the entrainment form. Both numerical simulation and mathematical analysis show that the morphodynamic processes predicted by the entrainment form are sensitive to sediment fall velocity. We suggest that the entrainment form of the Exner equation might be required when the sorting process of fine-grained sediment is studied, especially when considering relatively short timescales.

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