scholarly journals Hydrological and suspended sediment regime in the Kolubara River during the extreme year of 2014

2016 ◽  
Vol 18 (1) ◽  
pp. 32-46 ◽  
Author(s):  
Slavoljub DRAGIĆEVIĆ ◽  
Nenad ŽIVKOVIĆ ◽  
Ivan NOVKOVIĆ ◽  
Ana PETROVIĆ ◽  
Radislav TOŠIĆ ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Water Discharge ◽  
Suspended Sediment Transport ◽  
Water Runoff ◽  
Sediment Discharge ◽  
Daily Discharge ◽  
Large Water ◽  
Climate Events ◽  
Large Discharge

The previous methodology of sampling and determining the suspended sediment con­cen­tration (SSC) in the rivers of Serbia is characterized by a number of disadvantages, so that any re­search of this kind has a large water management impact. In the largest number of hydrological stations in Serbia, daily SSC were obtained based on only one sampling, which raises the question of the representativeness of such sample. Previous SSC – water discharge relationship and detailed analyses of errors in calculating the suspended sediment transport on the profile of Draževac were done for the year of 2004, when the annual difference was very high, which required a very detailed ana­lysis and methodological improvements. In order to define the sediment regime in the Kolubara River, precise monitoring of SSC has been implemented since 2013. The Kolubara River has an unfavourable water regime which is reflected in the excessiveness of water runoff, with floods that are sudden, expressive and short-term, and long-term low waters, so, that are why it is cha­rac­terized by a large discharge and SSC variability. Incidentally, monitoring also covered the year of 2014, when the area of western Serbia (in particular the Kolubara River Basin) was under the influence of extreme climate events that strongly reflected on the hydrological condition with the absolute highest daily discharge. A total of 220 water samples were collected on Draževac gauging station in 2014, in order to determine SSC and sediment discharge. The total number of days covered was 206, which means that there were even more samplings per day, when the discharge was changing fast. The minimal daily measured SSC was only 0.0016 g/l and the maxi­mal recorded value of SSC was 2.6122 g/l and was measured in May at the water discharge of 1 260 m3/s. Тhe total amount of sus­pended sediment discharge at the profile of Draževac in 2014 was 1 104 435 t (the spe­ci­fic suspended sediment yield – 308 t/sqkm/yr). The main objective of this study is to improve SSC – water discharge relationship in the Kolubara River based on the extreme hydrological conditions in 2014.

scholarly journals Estimating long term sediment yields from sediment core analysis

2010 ◽  
Vol 42 (1) ◽  
pp. 115-126 ◽  
Author(s):  
Patricia Kennie ◽  
Jim Bogen ◽  
Hans Olsen
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Sediment Core ◽  
Water Discharge ◽  
Sediment Cores ◽  
Monitoring Station ◽  
Suspended Sediment Transport ◽  
Core Analysis ◽  
Sediment Yields

Estimating long term sediment yields from sediment core analysis Sediment cores from lakes and reservoirs can be used to estimate sediment yields. In proglacial lakes, the bed sediment typically accumulates as varves, reflecting changes in seasonal and annual sedimentation. This report compares the results from two different methods of measuring suspended sediment transport in a Norwegian glacial river and lake. Sediment yields obtained from a study of sediment cores in the proglacial lake Nigardsvatn along with measurements of the delta topset were compared with a 25-year record of sediment transport based on automatic water sampling and water discharge measurements at a monitoring station at the inflowing river. During the period from 1980 to 2005, analyses of sediment cores taken from the lake bed along with measurements and grain size distribution analysis of the delta indicated that a volume of 175,670 to 202,697 m3 was deposited in the lake Nigardsvatn and corresponding river delta. The year 1980 was selected as a convenient starting point because a large-magnitude flood with a 100-year recurrence interval occurred at the end of 1979, leaving an easily recognizable sediment layer and accurate reference point. Sediment cores were taken at a total of 24 locations throughout the lake and 25 locations in the delta. The densities of the sediment cores were found to vary between 1.3 and 1.5 g/cm3 during the period examined in this study, giving a total suspended sediment load of between 175,670 and 202,697 tons. The measurements carried out at the sediment station in the glacier melt-water river gave a value of 294,800 tons during the same period. A final value of 211,100 tons is calculated from the monitoring station results after deduction of the sediment fraction which passes through the lake without being deposited. This gives a discrepancy between the two methods of 8,403 to 35,430 tons (4-20%). This can be partially attributed to the difficulties of measuring the water discharge in the unstable glacier meltwater river. In conclusion, sediment cores may be used to extrapolate or correct measurements from sediment monitoring stations over longer periods but caution should be made when considering single years.

scholarly journals Field methods of a near-bed suspended sediment experiment in the Yangtze River, China

2020 ◽  
Vol 13 (21) ◽  
Author(s):  
Caiwen Shu ◽  
Guangming Tan ◽  
Yiwei Lv ◽  
Quanxi Xu
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Dynamic Equilibrium ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Common Method ◽  
Sediment Discharge ◽  
Improved Method ◽  
The Common ◽  
The Impact

AbstractUsing experimental data of near-bed suspended sediment concentrations at five typical hydrometric stations of the Three Gorges Reservoir at the early reserving stage, the differences were investigated between the common method and improved method during flood seasons and non-flood seasons. The impact of taking measurements below 0.2 times the water depth on the results was discussed. The results show that the average discharges and velocities at each station calculated by the common method were slightly larger than those calculated by the improved method. Regarding the suspended sediment concentration at each station, the errors in the reservoir and downstream channels in dynamic equilibrium state were small, and the largest errors occurred where the river bed was strongly scoured in the downstream reach below the large dam. There was no significant relationship between water discharge and flow velocity, and the missed measurement phenomenon also occurred. The sediment discharge error was affected by the suspended sediment concentration, implying that errors usually occurred in channels with serious erosion during flood seasons. The correction coefficients (R2) of sediment discharge at each station were given during the experiment, which showed that the sediment discharges at the hydrometric stations where a large amount of sediment transport occurred near the river bottom, needed to be modified. Furthermore, the test methods proposed in this study were applied to calculate the sediment discharges of three rivers, and the results indicate that this method can narrow the gap between bathymetric comparisons and sediment load measurements.

scholarly journals Using artificial neural network (ANN) for prediction of sediment loads, application to the Mellah catchment, northeast Algeria

2017 ◽  
Vol 33 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Housseyn Bouzeria ◽  
Abderrahmane N. Ghenim ◽  
Kamel Khanchoul
Keyword(s):  
Suspended Sediment ◽  
Time Series Data ◽  
Water Discharge ◽  
Absolute Error ◽  
Coefficient Of Determination ◽  
Series Data ◽  
Sediment Discharge ◽  
Statistical Parameters ◽  
Discharge Data ◽  
Sediment Loads

AbstractIn this study, we present the performances of the best training algorithm in Multilayer Perceptron (MLP) neural networks for prediction of suspended sediment discharges in Mellah catchment. Time series data of daily suspended sediment discharge and water discharge from the gauging station of Bouchegouf were used for training and testing the networks. A number of statistical parameters, i.e. root mean square error (RMSE), mean absolute error (MAE), coefficient of efficiency (CE) and coefficient of determination (R2) were used for performance evaluation of the model. The model produced satisfactory results and showed a very good agreement between the predicted and observed data. The results also showed that the performance of the MLP model was capable to capture the exact pattern of the sediment discharge data in the Mellah catchment.

scholarly journals LAJU ANGKUTAN SEDIMEN MELAYANG DI SUNGAI WIMBI SUB DAS WIMBI KABUPATEN POSO

2021 ◽  
Vol 9 (1) ◽  
pp. 43
Author(s):  
Herman Harijanto ◽  
Abdul Wahid ◽  
Arief Sudhartono ◽  
Nikteri Perori
Keyword(s):  
River Water ◽  
Cross Section ◽  
Loading Rate ◽  
Water Discharge ◽  
Survey Method ◽  
Water Runoff ◽  
Sediment Loading ◽  
Sediment Discharge ◽  
The Cross ◽  
The Relationship

The research purpose was to determine of floating sediment loading rate which transported along Wimbi river water runoff and analyzed the relationship between water discharge with floating sediment discharge in the Wimbi river. The method used in this study was a survey method, namely by conducting direct measurements in the field, including: measurement of water discharge and water sampling for analysis of floating sediment content. Parameter  measured for the purpose of analyzing the sediment loading rate, namely floating sediment concentration Cs (mg / l), river water discharge Q (m3 / sec) and floating sediment discharge Qs (kg / sec). The relationship between water discharge and sediment discharge was analyzed using a suspended sediment rating curve. The results showed the flow of river water flowing at the cross section of the Wimbi river ranged from 0.88 m3 / sec - 13.7 m3 / sec (average of 6.17 m3 / sec). Furthermore, the height of the water level (H) flowing in the cross section of the Wimbi river ranged from 0.5 to 1.84 m with  average = 1.14m. Sediment loading rates float in the Wimbi river ranged from 2.110 - 99.511kg / sec (average of 35.222 kg / sec). The analyzed results of the relationship between water discharge and floating sediment discharge obtained a positive relationship with a correlation value of 0.96.

Simulation of Suspended Sediment Transport in a Tidal River

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1421-1430 ◽  
Author(s):  
T. Kusuda ◽  
T. Futawatari
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Transport Model ◽  
Transport Processes ◽  
Tidal River ◽  
Numerical Dispersion ◽  
Suspended Sediment Transport ◽  
Fluid Mud ◽  
River Modeling

Based on the results of field observation in a tidal river, modeling of sediment transport processes is performed and the suspended sediment transport over a long term is simulated with a newly developed procedure, in which the Lagrangian reference frame is used in order to reduce numerical dispersion. The suspended sediment transport in the tidal river is calculated with erosion and deposition of sediments, consolidation of fluid mud to bed mud, and transport by turbidity current. Sediment transport processes concerned with formation and maintenance of turbidity maxima are sufficiently simulated for a fortnightly cycle with the Lagrangian sediment transport model (LSTM).

Effect of decontamination on sediment discharge from mountain stream to river and cesium transfer in Yamakiya district

2020 ◽  
Author(s):  
Fumiaki Makino ◽  
Yuichi Onda ◽  
Keisuke Taniguchi ◽  
Mitbaa Slim ◽  
Yoshifumi Wakiyama ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Sediment Dynamics ◽  
Forest Area ◽  
Mountain Stream ◽  
Sediment Runoff ◽  
Water Runoff ◽  
Target Area ◽  
Sediment Discharge ◽  
Middle Point ◽  
Middle Stream

<p>After the accident of the Fukushima nuclear power plant, decontamination works had been conducted from 2013 to 2017 in the area of heavly contamination by fallout radionuclides. Although decontamination is conductive to decrease the air dose rate, associated disturbances of soil, such as scraping, reversal tillage, and soil dressing. These decontamination works, in turn, could increase the sediment discharge to downstream, but no studies are available on the effect of the decontamination in upstream headwaters that affects sediment discharge in rivers. Furthermore, decontamination has been carried out in the target area, the Yamakiya area, from 2013, and decontamination has been completed in the spring of 2016, decontamination work has been completed in 2017, and the residents have been returned. The sediment runoff due to human activities can be different from the sediment runoff due to decontamination.</p><p>The purpose of this study was to study the relationship between sediment dynamics and Cs dynamics due to decontamination, and the changes in sediment dynamics due to the return of residents. Observations and historical data were analyzed at Iboishi mountain in the forest and the middle stream of Kuchibuto. We have been monitoring suspended sediment Cs-137 concentration, water runoff, and suspended sediment runoff since 2014 at the middle point of the Kuchibuto River and since 2013 at Mt.Iboishi. The slope of the approximation line was compared with the LQ curve for comparison of the amount of sediment runoff. In the middle of the Kuchibuto river, it was 1.54 in 2014, 2.28 in 2015, 2.12 in 2016, 0.164 in 2017, and 0.189 in 2018. At Iboishi mountain in the forest, it was 1.72 in 2014, 0.947 in 2015, 1.39 in 2016, 0.219 in 2017, and 1.15 in 2018. The same tendency was shown in the slopes of the LQ curves in the middle part of the Kuchibuto river and the Iboishi mountain in the forest area. The Cs concentration was high until November 2015, but since then, the Cs concentration has decreased. These results suggest that the increased sediment discharge due to decontamination of the forest area affected the sediment discharge in the middle stream of the Kuchibuto River.</p>

Formulating an elasticity approach to quantify the effects of ecological restoration and climate variability on streamflow and sediment discharge changes in the Loess Plateau of China

2020 ◽  
Author(s):  
Guangyao Gao
Keyword(s):  
Climate Variability ◽  
Suspended Sediment ◽  
Ecological Restoration ◽  
Loess Plateau ◽  
Yellow River ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Sediment Discharge ◽  
The Loess Plateau ◽  
Check Dams

<p>Ecological restoration (ER) has strong consequences on hydrological responses. The China’s Loess Plateau (LP) contributed nearly 90% of sediment load in the Yellow River, which was once the world’s largest carrier of fluvial sediment. ER efforts including the soil and water conservation measures (SWCMs, especially terracing and construction of check dams) since 1950s and large-scale ecological restoration campaigns such as Grain-for-Green project (i.e., returning sloping cropland to afforestation and pasture reestablishment) in 1999, has resulted in extensive land use/cover change, leading to considerable decreases of streamflow (Q), suspended sediment yield (SSY) and sediment concentration (C) in the LP over the past 60 years. However, it remains challenging to quantify the impacts of ER and climate variability on declines of Q and especially SSY. In this study, we formulate the notion of elasticity of sediment discharge, by associating SSY change to climate variability and ER over the period 1950s to 2014. Our results strongly support the hypothesis that changes to both streamflow volumes and to the suspended sediment concentration versus water discharge (C-Q) relationships result in reduced SSY, so that streamflow is reduced but runs clearer. We find that two of the ER strategies resulted in weaker relative impacts of climate variability, largely by reducing streamflow (by 55% to 75%). Meanwhile, ER predominantly decreased SSY (by 63% to 81%). Regarding ER practices, (i) the predominant measure acting to reduce SSY changed, over time, from engineering to reforestation; (ii) check-dams preferentially act to regulate the C-Q relationships whereas reforestation preferentially acts to moderate streamflow. Overall, our results suggest that a combination of engineering and vegetation measures is critical to achieving high-efficiency ER. While change to the ER strategy increased the efficiency of streamflow for SSY control, the lost water discharge per unit SSY reduction increased from 5.2 to 6.4 m<sup>3</sup>·t<sup>-1</sup>. Conflicting demands for water necessitate that further ER should target precision management by revegetation of targeted areas in the Loess Plateau.</p>

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