Recent flow regime and sedimentological evolution of a fluvial system as the main factors controlling spatial distribution of arsenic in groundwater (Red River, Vietnam)

2016 ◽  
pp. 72-73 ◽  
Author(s):  
J Kazmierczak ◽  
F Larsen ◽  
R Jakobsen ◽  
D Postma ◽  
H Sø ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Flow Regime ◽  
Red River ◽  
Fluvial System ◽  
Arsenic In Groundwater ◽  
Main Factors

scholarly journals Spatial distribution of arsenic in groundwater in the northwestern Hanoi

2021 ◽  
Vol 63 (11) ◽  
pp. 19-23
Author(s):  
Thi Duyen Vu ◽  
◽  
Thi Mai Tran ◽  
Thi Kim Trang Pham ◽  
Mai Lan Vi ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Arsenic Concentration ◽  
Red River ◽  
Arsenic Content ◽  
Red River Delta ◽  
Arsenic Distribution ◽  
Arsenic In Groundwater ◽  
Guideline Value ◽  
Wide Range ◽  
Major River

Arsenic contamination in groundwater is commonly found in alluvial plains of major river basins, in which the Red river delta has also been reported to be contaminated with high levels of arsenic. In this study, groundwater from 50 household wells was collected to study the spatial distribution of arsenic in northwestern Hanoi. The results showed that arsenic concentration in groundwater varied in a wide range of less than 5 to 334 μg/l, of which up 62% of the wells exceeded the WHO guideline value of 10 μg/l for arsenic content in drinking water. Arsenic groundwater in this area is unevenly distributed throughout the area, high arsenic concentrations are found in a narrow band between Red river and Day river. This pattern of arsenic distribution is strongly related to the sediment age, sedimentary processes, and it is also modified by local groundwater flow parts and the occurrence of hydraulic connection between aquifers, which are observed in the study area. Arsenic is released into the groundwater during the reductive dissolution of arsenic-bearing minerals under the presence of organic matter.

Estimation of the Environmental Flow Regime to Deter-mine the Minimum Flow for Pollution Reduction: Wadi Zomar - Palestine as a Case Study

2020 ◽  
Vol 8 (1) ◽  
pp. 21-33
Author(s):  
Saed Khayat
Keyword(s):  
Flow Regime ◽  
Base Flow ◽  
Pollution Reduction ◽  
Flood Inundation ◽  
Healthy Environment ◽  
Floodplain Inundation ◽  
Main Factors ◽  
Bar Formation

Possible factors that play a role in restoring a flow regime that supports a healthy environment were identified for Wadi Zomar, Palestine. The hydrograph shows that threshold discharges for bed drying are less than 0.14 m3/s, bar formation is less than 0.4 ms/s and floodplain inundation events are over 3 m3/s. The HEC-RAS model suggests a continuous discharge throughout the year that maintains the base flow in the range of 0.5 m3/s. The model suggests that the restoration process is controlled by two main factors: role of sufficient flow and flood inundation frequency

The changing flow regime and sediment load of the Red River, Viet Nam

2007 ◽  
Vol 334 (1-2) ◽  
pp. 199-214 ◽  
Author(s):  
Thi Phuong Quynh Le ◽  
Josette Garnier ◽  
Billen Gilles ◽  
Théry Sylvain ◽  
Chau Van Minh
Keyword(s):  
Flow Regime ◽  
Sediment Load ◽  
Red River ◽  
Viet Nam

scholarly journals The controlling of paleo-riverbed migration on Arsenic mobilization in groundwater in the Red River Delta, Vietnam

2020 ◽  
Vol 42 (2) ◽  
pp. 161-175
Author(s):  
Dang Tran Trung ◽  
Nguyen Thi Nhan ◽  
Than Van Don ◽  
Nguyen Kim Hung ◽  
Jolanta Kazmierczak ◽  
...  
Keyword(s):  
Groundwater Modeling ◽  
Arsenic Concentration ◽  
River Delta ◽  
Red River ◽  
Arsenic Content ◽  
Red River Delta ◽  
Arsenic Mobilization ◽  
Reducing Conditions ◽  
Arsenic In Groundwater ◽  
Combination Of Methods

In the Red River Delta, the concentrations of Arsenic in groundwater of alluvial dominated systems are very high, exceeding the WHO’s permissible. The correlation between the Arsenic concentrations in groundwater and the age of Holocene sediment as a key controlling groundwater Arsenic concentration in the Red River delta has been investigated. The evolution of sediments in the Holocene is closely related to paleo-riverbed migration in the past. A combination of methods is implemented including remote sensing, multi-electrode profiling (MEP), gamma-logging, drilling, soil sample and groundwater modeling. The resul has identified the shape, sediment compositions and location of the six paleo-riverbed periods. The age of the paleo-riverbed is determined by drilling, soil sampling and optically stimulated luminescence (OSL) in the laboratory. The oldest sediments is 5.9±0.4 ka BP in Phung Thuong near the mountain, the youngest one is from 0.4÷0.6 ka BP in H-transect near the Red River and the rest of the other is around 3.5 ka BP. The modeling results by using MODFLOW and MT3D show that the dynamics of paleo-riverbeds controlling Arsenic mobilization in groundwater in the Red River Delta. When the river moved to another position, the current river position at that time was filled with younger sediments and became paleo-riverbed formation with reducing conditions, Arsenic content which was adsorbed in the previous stage then released into groundwater. Therefore, Arsenic concentration in groundwater of young Holocene sediments is higher than in older ones which elucidates that paleo-riverbed migration controls on Arsenic mobilization in groundwater in the study area.

scholarly journals The Spatial Distribution of Bed Sediment on Fluvial System: A Mini Review of the Aceh Meandering River

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Muhammad Irham
Keyword(s):  
Spatial Distribution ◽  
Bed Load ◽  
Sieve Analysis ◽  
Left Bank ◽  
Fluvial System ◽  
Dynamic Interactions ◽  
Meandering River ◽  
River Bed ◽  
Meander Bends ◽  
Mechanical Weathering

Dynamic interactions of hydrological and geomorphological processes in the fluvial system result in accumulated deposit on the bed because the capacity to carry sediment has been exceeded. The bed load of the Aceh fluvial system is primarily generated by mechanical weathering resulting in boulders, pebbles, and sand, which roll or bounce along the river bed forming temporary deposits as bars on the insides of meander bends, as a result of a loss of transport energy in the system. This dynamic controls the style and range of deposits in the Aceh River. This study focuses on the spatial distribution of bed-load transport of the Aceh River. Understanding the spatial distribution of deposits facilitates the reconstruction of the changes in controlling factors during accumulation of deposits. One of the methods can be done by sieve analysis of sediment, where the method illuminates the distribution of sediment changes associated with channel morphology under different flow regimes. Hence, the purpose of this mini review is to investigate how the sediment along the river meander spatially dispersed. The results demonstrate that channel deposits in the Aceh River are formed from four different type of materials: pebble deposited along upstream left bank; sand located on the upstream, downstream, and along meander belts; and silt and clay located along the cut bank of meander bends. Because of different depositional pattern, the distribution of the sediment along the river can be used as a surrogate to identify bank stability, as well as to predict critical geometry for meander bend initiation

scholarly journals What Are the Most Important Factors Influencing Springtail Tetrodontophora bielanensis?

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 858
Author(s):  
Strahinja Mladenović ◽  
Jan Materna ◽  
Tereza Brestovanská ◽  
Jakub Horák
Keyword(s):  
Spatial Distribution ◽  
Czech Republic ◽  
Negative Influence ◽  
Positive Influence ◽  
Cold Climate ◽  
The Czech Republic ◽  
Soil Layers ◽  
Factors Influencing ◽  
Main Factors ◽  
Landscape Level

The springtail, Tetrodontophora bielanensis, dwells in the litter and upper soil layers. This arthropod mainly inhabits humid litter and soil and prefers a cold climate. We determined the main factors influencing this springtail in forests at the landscape level in Krkonoše and site level in Orlické hory in the Czech Republic. We used passive trunk-tree traps. These traps are highly effective for sampling flightless fauna. We used 128 traps in Krkonoše and 17 traps in Orlické hory. The springtail was significantly positively influenced by the presence of Norway spruce (Picea abies) at the landscape level. Springtails’ abundance was, furthermore, influenced by the spatial distribution of the sampling sites. The negative influence of bark coverage and the presence of fungi, and positive influence of an increasing dimension of trees were significant at the site level. We argue for a more diversified management of mountainous forests with respect to forest history. This appears to be also important for mountainous forests in protected areas.

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