CHARACTERISTICS OF WATER AND SEDIMENT DISTRIBUTION IN THE LOTUS-ROOT-SHAPE COMPOUND CHANNELS

Abstract. The Hoa Binh dam (HBD), located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 109 m3 and was commissioned in December 1988. Although it is important for flood prevention, electricity production and irrigation in northern Vietnam, the Hoa Binh dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from a 50-year data set of water discharge and suspended sediment concentration (1960–2010), and the distribution of water and sediment across the nine mouths of the delta was simulated using the MIKE11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 9%, the yearly suspended sediment flux dropped, on average, by 61% at Son Tay near Hanoi (from 119 to 46 × 106 t yr−1). Along the coast, reduced sedimentation rates are coincident with the lower sediment delivery observed since the impoundment of the Hoa Binh dam. Water regulation has led to decreased water discharge in the wet season (−14% in the Red River at Son Tay) and increased water discharge in the dry season (+12% at the same station). The ratios of water and suspended sediment flows, as compared to the total flows in the nine mouths, increased in the northern and southern estuaries and decreased in the central, main Ba Lat mouth. The increasing volume of dredged sediments in the Haiphong harbour is evidence of the silting up of the northern estuary of Cam–Bach Dang. The effect of tidal pumping on enhanced flow occurring in the dry season and resulting from changed water regulation is discussed as a possible cause of the enhanced siltation of the estuary after Hoa Binh dam impoundment.

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Contamination Of Perfluorinated Compounds In Sediment of The Cau River, Vietnam

10.21203/rs.3.rs-573006/v1 ◽

2021 ◽

Author(s):

Hoai Tran ◽

Dieu-Anh Van ◽

Duc Thao Vu ◽

Trung Hai Huynh

Keyword(s):

Environmental Pollutants ◽

Clay Content ◽

Organic Carbon Content ◽

Environmental Matrices ◽

Sediment Distribution ◽

Factors Affecting ◽

Water And Sediment ◽

Kd Values ◽

Pfoa Concentration ◽

Total Concentrations

Abstract Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are recognized as emerging environmental pollutants because of their high persistence in various environmental matrices and toxic effects on humans and animals. In Vietnam, PFOA and PFOS have been detected in surface water and sediment in recent studies. The objectives of this study were to evaluate the occurrence of PFOS and PFOA in the sediment of the Cau river, Thai Nguyen city to determine the partition coefficient between water and sediment, and to elucidate the environmental factors affecting the sorption of PFOS and PFOA to sediment. The concentration of PFOS and PFOA in surface sediment ranged from 1.19 ng/g to 4.73 ng/g and 0.17 ng/g to 1.78 ng/g, respectively, with the highest concentrations, are recorded in the areas that receiving wastewater from domestic and industrial activities. Depending on the depth, the total concentrations of PFOS and PFOA ranged from 8.41 to 19.25 ng/g and tended to decrease with increasing sediment depth. The concentrations in the surface sediments are lower than the second layer, indicating a downward trend in the use and consumption of these compounds in recent years. The water-sediment distribution coefficient (Kd) is relatively different for PFOS and PFOA, with log Kd values ranged from 1.31–1.86 and 0.08–1.31 for PFOS and PFOA, respectively. This study also confirms that the total organic carbon content is the physiochemical property that significantly affected the adsorption to sediments of PFOS and PFOA. No apparent relation was found between PFOS, PFOA concentration in sediment and clay content nor sediment particle size.

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Impact of the Hoa Binh Dam (Vietnam) on water and sediment budgets in the Red River basin and delta

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-11-333-2014 ◽

2014 ◽

Vol 11 (1) ◽

pp. 333-370 ◽

Cited By ~ 5

Author(s):

D. V. Vu ◽

S. Ouillon ◽

D. T. Tran ◽

V. C. La

Keyword(s):

Suspended Sediment ◽

River Basin ◽

Water Discharge ◽

Sediment Flux ◽

Red River ◽

Tidal Range ◽

Sediment Distribution ◽

Water And Sediment ◽

Red River Basin ◽

Hoa Binh

Abstract. The Hoa Binh Dam, located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 109 m3 and was commissioned in December 1988. Although being important for flood prevention, electricity production, and irrigation in northern Vietnam, the Hoa Binh Dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from 50 yr dataset of water discharge and suspended sediment concentration (1960–2010) and the distribution of water and sediment across the nine mouths of the delta was calculated using the MIKE 11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 8.8%, the yearly suspended sediment flux dropped, on average from 119 to 43 × 106 t yr−1 at Son Tay near Hanoi, and from 85 to 35 × 106 t yr−1 in the river mouths. Water regulation has led to decreased water discharge in the wet season and increased water discharge in the dry season. Suspended sediment discharge proportionally increased in northern and southern estuaries and decreased through the main and central Ba Lat mouth. Tidal pumping, which causes a net sediment flux from the coast to the estuary at low discharge, is high in the northern delta, as a consequence of the high tidal range (up to 4.5 m in spring tide; diurnal tide). The shifts in the dynamic and characteristics of the turbidity maximum zone in the Cam-Bach Dang estuary are probably the cause of the enhanced sediment deposition in the Haiphong harbor. Along the coast, the reduced sedimentation rates are coincident with the lower sediment delivery that has been observed since the impoundment of the Hoa Binh Dam.

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Experimental Study on Flow and Sediment Distribution at Off-Take Channel

International Journal of Environmental Science and Development ◽

10.18178/ijesd.2021.12.2.1315 ◽

2021 ◽

Vol 12 (2) ◽

pp. 35-41

Author(s):

Lamisa Malik ◽

◽

M. Abdul Matin

Keyword(s):

Field Data ◽

Physical Simulation ◽

Low Flow ◽

Sedimentation Pattern ◽

Fluvial Systems ◽

Sediment Distribution ◽

Water And Sediment ◽

Flow Visualizations ◽

Complex Features ◽

Distribution Of Flow

River off-take is one of the complex features in fluvial systems and the distribution of flow, and sediments along the branches are still a matter of research. This paper deals with a physical simulation on an off-take channel for understanding the flow and sediment distribution in the vicinity. Laboratory-based test runs have been carried out by changing the discharges and the angles off-take. A total of eighteen test runs have been conducted for three discharge conditions with three off-take angles. Two equations for predicting water and sediment discharge ratios have been proposed as a function of Froude number, channel geometry and off-take angel. Flow visualizations have also been carried out in the vicinity of the off-take for understanding erosion and sedimentation pattern. Flow and sediment movement patterns were carefully observed during the simulation and four distinguished zone formations have been noted in the vicinity. Finally, validations of the developed equations have been done with the field data from selected river off-take systems of Bangladesh. Validation results of field data show mean discrepancy ratios of 0.83 for the discharge equation and 0.89 for sediment equation during low flow.

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Preliminary investigation of the presence of PFOS and PFOA in water and sediment in Cau river

Ministry of Science and Technology, Vietnam ◽

10.31276/vjst.63(11).23-27 ◽

2021 ◽

Vol 63 (11) ◽

pp. 23-27

Author(s):

Hoai Le Tran ◽

◽

Duc Thao Vu ◽

Trung Hai Huynh ◽

Thi Lien Hoang ◽

...

Keyword(s):

Liquid Phase ◽

Aquatic Environment ◽

Octanoic Acid ◽

Preliminary Investigation ◽

Environmental Pollutants ◽

Environmental Matrices ◽

Sediment Distribution ◽

Industrial Activities ◽

Water And Sediment ◽

Total Concentrations

Perfluoro-octane sulfonate (PFOS) and Perfluoro-octanoic acid (PFOA) are recognised as emerging environmental pollutants because of their high persistence in various environmental matrices and toxic effects on humans and animals. The objectives of this study were to preliminarily investigate the occurrence of PFOS and PFOA in the water and sediment of the Cau river in Thai Nguyen city. The concentration of PFOS and PFOA in water ranged from <LOQ-0.67 ng/l and 0.05-8.11 ng/l; 1.19-4.73 ng/g, and 0.17-1.78 ng/g in sediment, respectively. The highest total concentrations of PFOS and PFOAwere recorded in the areas that directly received wastewater from domestic and industrial activities. The water-sediment distribution coefficient (Kd) was relatively different for PFOS and PFOA, with Kd ranged from 20.51-72.83 l/g and 1.21-20.31 l/g for PFOS and PFOA, respectively. This result suggested the distribution of PFOS and PFOA between water and sediment, in which PFOS will preferentially deposit in the sediment, and PFOA will tend to distribute in the liquid phase of the aquatic environment.

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Performance of Sumur Gendong (SeDrainPond) Technology on Harvesting Water and Sediment with Respect to Effective Rainy Days

International Review of Civil Engineering (IRECE) ◽

10.15866/irece.v10i1.16273 ◽

2019 ◽

Vol 10 (1) ◽

pp. 41 ◽

Cited By ~ 1

Author(s):

Ignatius Sriyana ◽

Imam Wahyudi ◽

Rick Heikoop ◽

Kusmiyati Florentina ◽

Haryono Putro

Keyword(s):

Water And Sediment ◽

Rainy Days

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Evaluation of Capacity of Salandi Reservoir Using Remote Sensing Data Along With Qgis Software

International Journal of Emerging Research in Management and Technology ◽

10.23956/ijermt.v6i8.164 ◽

2018 ◽

Vol 6 (8) ◽

pp. 339

Author(s):

Rupali Dhal ◽

D. P. Satapathy

Keyword(s):

Remote Sensing ◽

Satellite Data ◽

Remote Sensing Data ◽

Project Work ◽

Space Technology ◽

Reservoir Water ◽

Sediment Distribution ◽

Sensing Data ◽

Spread Area ◽

Water Spread

The dynamic aspects of the reservoir which are water spread, suspended sediment distribution and concentration requires regular and periodical mapping and monitoring. Sedimentation in a reservoir affects the capacity of the reservoir by affecting both life and dead storages. The life of a reservoir depends on the rate of siltation. The various aspects and behavior of the reservoir sedimentation, like the process of sedimentation in the reservoir, sources of sediments, measures to check the sediment and limitations of space technology have been discussed in this report. Multi satellite remote sensing data provide information on elevation contours in the form of water spread area. Any reduction in reservoir water spread area at a specified elevation corresponding to the date of satellite data is an indication of sediment deposition. Thus the quality of sediment load that is settled down over a period of time can be determined by evaluating the change in the aerial spread of the reservoir at various elevations. Salandi reservoir project work was completed in 1982 and the same is taken as the year of first impounding. The original gross and live storages capacities were 565 MCM& 556.50 MCM respectively. In SRS CWC (2009), they found that live storage capacity of the Salandi reservoir is 518.61 MCM witnessing a loss of 37.89 MCM (i.e. 6.81%) in a period of 27 years.The data obtained through satellite enables us to study the aspects on various scales and at different stages. This report comprises of the use of satellite to obtain data for the years 2009-2013 through remote sensing in the sedimentation study of Salandi reservoir. After analysis of the satellite data in the present study(2017), it is found that live capacity of the reservoir of the Salandi reservoir in 2017 is 524.19MCM witnessing a loss of 32.31 MCM (i.e. 5.80%)in a period of 35 years. This accounts for live capacity loss of 0.16 % per annum since 1982. The trap efficiencies of this reservoir evaluated by using Brown’s, Brune’s and Gill’s methods are 94.03%, 98.01and 99.94% respectively. Thus, the average trap efficiency of the Salandi Reservoir is obtained as 97.32%.

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