scholarly journals Analysis of Suspended Sediment in the Anavilhanas Archipelago, Rio Negro, Amazon Basin

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1073 ◽  
Author(s):  
Rogério Ribeiro Marinho ◽  
Naziano Pantoja Filizola Junior ◽  
Édipo Henrique Cremon
Keyword(s):  
Suspended Sediment ◽  
Amazon Basin ◽  
Water Discharge ◽  
Left Bank ◽  
River Channels ◽  
Total Suspended Sediment ◽  
Negro River ◽  
Discharge Velocity ◽  
The Mean ◽  
The Right

This article analyzes the flows of water and total suspended sediment in different reaches in the lower course of the Negro River, the largest fluvial blackwater system in the world. The area under study is the Anavilhanas Archipelago, which is a complex multichannel reach on the Negro River. Between the years 2016 and 2019, data about water discharge, velocity, and concentration of total suspended solids (TSS) were acquired in sample sections of the Negro River channels located upstream, inside, and downstream of the Anavilhanas Archipelago. In the study area, the Negro River drains an area greater than 700,000 km2, and the mean water discharge observed before the Anavilhanas was about 28.655 m3·s−1, of which 97% flows through two channels of the Archipelago close to the right and left banks. The mean TSS concentration of the Negro River upstream and downstream the Archipelago was 3.28 mg·L−1 and 1.63 mg·L−1, respectively. Within the Archipelago, we observed more TSS in the channel on the left bank of the Negro River (mean of 4.50 mg·L−1). The total suspended sediment discharge of the Negro River before (3.14 Mt·year−1) and after (1.43 Mt·year−1) the Anavilhanas Archipelago indicates a 55% retention of the suspended load due to the low water slope and reduced flow velocity caused by the backwater effect of Solimões River on the Negro River. The hydro-sedimentary scenario of the low course of the Negro River characterized in this study indicates a slow and continuous sedimentation process in the Anavilhanas Archipelago. The results presented will serve as a baseline to assess the impacts of the dams on the Branco River, the main tributary for both water and sediment in the Negro River basin.

scholarly journals Suspended Sediment Variability at the Solimões and Negro Confluence between May 2013 and February 2014

Geosciences ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 265 ◽  
Author(s):  
Thiago Marinho ◽  
Naziano Filizola ◽  
Jean-Michel Martinez ◽  
Elisa Armijos ◽  
André Nascimento
Keyword(s):  
Suspended Sediment ◽  
Satellite Images ◽  
Suspended Sediments ◽  
Left Bank ◽  
Sediment Samples ◽  
Negro River ◽  
The World ◽  
The Right ◽  
Sediment Variability ◽  
Solimões River

This study focuses on the confluence of two major rivers of the world, the Solimões River (white waters) and Negro River (black waters). Surface suspended sediment samples (SSC) and spectroradiometer taken along transverse profiles at 500 m intervals over a distance of 10 km, as well as satellite images (MODIS) during the hydrological year, were used to follow suspended sediment variability. In January and February, the confluence is dominated by white waters from the Solimões River in the two banks, and in June and July in the right bank by black waters from the Negro River and in the left bank by clear waters from the Solimões River. We found that indirect tools, such as reflectance obtained by spectrometer or MODIS images, can be used to determine surface suspended sediments in a contrasting zone.

scholarly journals Water discharge estimates from large radar altimetry datasets in the Amazon basin

2012 ◽  
Vol 9 (6) ◽  
pp. 7591-7611 ◽  
Author(s):  
A. C. V. Getirana ◽  
C. Peters-Lidard
Keyword(s):  
Data Assimilation ◽  
Amazon Basin ◽  
Water Discharge ◽  
Rating Curve ◽  
Radar Altimetry ◽  
Discharge Data ◽  
Modeling Uncertainties ◽  
The Mean ◽  
Relative Errors ◽  
The Impact

Abstract. In this study, we evaluate the use of a large radar altimetry dataset as a complementary gauging network capable of providing water discharge in ungauged regions within the Amazon basin. A rating-curve-based methodology is adopted to derive water discharge from altimetric data provided by Envisat at 444 virtual stations (VS). The stage-discharge relations at VS are built based on radar altimetry and outputs from a global flow routing scheme. In order to quantify the impact of modeling uncertainties on rating-curve based discharges, another experiment is performed using simulated discharges derived from a simplified data assimilation procedure. Discharge estimates at 90 VS are evaluated against observations during the curve fitting calibration (2002–2005) and evaluation (2006–2008) periods, resulting in mean relative RMS errors as high as 52% and 12% for experiments without and with assimilation, respectively. Without data assimilation, uncertainty of discharge estimates can be mostly attributed to forcing errors at smaller scales, generating a positive correlation between performance and drainage area. Mean relative errors (RE) of altimetry-based discharges varied from 15% to 92% for large and small drainage areas, respectively. Rating curves produced a mean RE of 54% versus 68% from model outputs. Assimilating discharge data decreases the mean RE from 68% to 12%. These results demonstrate the feasibility of applying the proposed methodology to the regional or global scales. Also, it is shown the potential of satellite altimetry for predicting water discharge in poorly-gauged and ungauged river basins.

scholarly journals The Role of the Rainfall Variability in the Decline of the Surface Suspended Sediment in the Upper Madeira Basin (2003–2017)

2021 ◽  
Vol 3 ◽  
Author(s):  
Irma Ayes Rivera ◽  
Jorge Molina-Carpio ◽  
Jhan Carlo Espinoza ◽  
Omar Gutierrez-Cori ◽  
Wilmar L. Cerón ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Amazon Basin ◽  
Environmental Changes ◽  
Rainfall Variability ◽  
Water Discharge ◽  
Critical Issue ◽  
Base Flow ◽  
Rainfall Time Series ◽  
Madeira River

The Madeira River rises in the Andes, draining the southwestern Amazon basin and contributing up to 50% of the Amazon River sediment load. The Porto Velho station monitors the Upper Madeira basin and is located just downstream of the Jirau and Santo Antonio hydropower dams. At this station, decreasing trend (p < 0.10) of the surface suspended sediment concentration (SSSC) has been documented during the sediment peak season (December to February) for the 2003–2017 period. This study aims to evaluate the role of the rainfall variability on this documented decreasing trend. For this purpose, we applied correlation and trend analysis in water discharge, SSSC and rainfall time series over the main tributaries of the Upper Madeira basin. The decline of SSSC in December is attributed to the reduction of rainfall in the Madre de Dios sub-basin from the start of the rainy season in October. However, the SSSC negative trend (p < 0.10) in January and February is associated with a shift in the magnitude of rainfall during these months in the Andean region after 2008, and the dilution associated with base flow. These results reveal that the decline of SSSC in the Madeira River should not be evaluated just on the basis of the data downstream from the dams, but also of the processes upstream in the Andean part of the basin. In a context of drastic anthropogenic climate and environmental changes, understanding the combined influence of regional hydroclimate variability and human actions on erosion and sediment transport remains a critical issue for the conservation of the Amazon-Andes system.

scholarly journals Sediment load estimation in the Mellegue catchment, Algeria

2016 ◽  
Vol 31 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Kaouther Selmi ◽  
Kamel Khanchoul
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Sediment Yield ◽  
Agricultural Land ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Sediment Loads ◽  
Recorded Data ◽  
The Mean ◽  
The Impact

AbstractSoil erosion by water and the impact of sediment transport on lakes and streams, can seriously degrade soil and create problems for both agricultural land and water quality. The present study has been carried out to assess suspended sediment yield in Mellegue catchment, northeast of Algeria. Regression analysis was used to establish a relationship between the instantaneous water discharge (Q) and the instantaneous suspended sediment concentration (C) based on all recorded data and seasonal ratings for the period 1970–2003. The regression technique used in this paper involved a division of data into discharge – based classes, the mean concentrations and discharges of which are used to develop power regressions, according to single and season ratings, through log-transformation. Sediment loads estimated by stratified rating curves reduced underestimations to a range from 2 to 4%. The mean annual sediment yield during the 34 years of the study period was 589.23 t·km−2·y−1. Sediment transport is dominated by fall rainstorms accounting for 41% of the annual load. The big supply of sediment during this season confirms the intense geomorphic work by fall storms caused by high intensity rainfall and low vegetation cover.

СALCULATED CHARACTERISTICS OF THE AVERAGE ANNUAL RUNOFF OF THE RIGHT-BANK AND LEFT-BANK PARTS OF THE RIVER BASIN DNIESTER TO THE CITY OF ZALISHCHYKY

2020 ◽  
pp. 58-72
Author(s):  
A.I. Boiko ◽  
O.V. Lobodzinskyi ◽  
О.I. Lukіanets
Keyword(s):  
River Water ◽  
River Basin ◽  
Water Flow ◽  
Stream Flow ◽  
Water Discharge ◽  
Continuous Series ◽  
Left Bank ◽  
Average Annual Runoff ◽  
Annual Water ◽  
The Right

The Dniester River is the second longest and most watery river in Ukraine, which is characterized by heterogeneity and diversity of conditions for the formation of water flow, both in terms of its length and numerous tributaries. The right-bank and left-bank parts of the Dniester River basin are quite different in terms of physical and geographical conditions, drainage network density, water regime and river water content. The object of the study is the average annual water flow of the rivers of the Dniester River basin, the subject is its calculated characteristics of different probabilities of exceeding. The purpose of the study is to analyze, systematize, generalize and compare the calculated characteristics of the average annual water flow of rivers of the right-bank and left-bank parts of the Dniester basin. Input data is based on the average annual river water discharge from 50 stream flow measuring stations in the Dniester River basin (to Zalishchyky). The data bank was formed from the beginning of observations until 2016. 89% of 28 right-bank stream flow measuring stations have a continuous series of more than 50 years, and 86% of 22 left-bank stream flow measuring stations have a continuous series of observations of more than 50 years. As for the catchment areas of rivers in the closing areas, the right bank is dominated by small ones – 64% of 28 stations have an area of less than 500 km2 and 25% – from 500 to 1,000 km2. 37% of 22 stations on the left bank have a catchment area of less than 500 km2 and 41% – from 500 to 1,000 km2. According to statistical criteria, the series of observations of the average annual river water discharge in both parts were mainly homogeneous and representative. Analytical distribution curves were calculated by the method of moments, as the coefficients of variation do not exceed 0.50. Generalization and comparison of the calculated characteristics of the average annual water flow of different probabilities of exceeding the rivers of the right-bank and left-bank parts of the Dniester basin have shown that the smallest scatter of certain analytical ordinates is observed for the probability of exceeding 50%, the transition coefficients from the norm are close to 1. The greatest spread of variation of ordinates is observed at extreme probabilities of excess of distributions, that is 0,01 % and 99 %. Analysis of the ranges of variability of transition coefficients from the norm of average annual water consumption has shown that the intensity of their change in the region of rare probabilities (0.01, 0.1, 1 %%) on the left bank is more significant than on the right bank of the Dniester basin. As for low-water supplies (95, 97, 99 %%), their ranges of variability coincide in both studied parts.

scholarly journals Suspended sediment transport estimation in Negro River (Amazon Basin) using MSI/Sentinel-2 data

2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Rogério Ribeiro Marinho ◽  
Naziano Pantoja Filziola ◽  
Jean-Michel Martinez ◽  
Tristan Harmel
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Amazon Basin ◽  
Suspended Sediment Transport ◽  
Negro River ◽  
Sentinel 2

scholarly journals STREAMFLOW AND SUSPENDED SEDIMENT LOAD TRENDS IN TROTUȘ DRAINAGE BASIN: GEOMORPHIC IMPLICATIONS

2020 ◽  
Vol 14 (2) ◽  
pp. 67-87
Author(s):  
Dan DUMITRIU
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Drainage Basin ◽  
Trend Test ◽  
Suspended Sediment Load ◽  
River Channels ◽  
Increasing Trend ◽  
The Mean ◽  
Slope Estimator ◽  
Streamflow Trend

The research focusing on the trends of the streamflow and suspended sediment, as well as on the controls involved in these changes, are currently topics of significant interest in fluvial geomorphology. In this context, the aim of this study is to analyze the trends of the streamflow discharge and the sediment load based on a geomorphological approach of the relations between the two variables. These trends were assessed based on three testing methods frequently employed in hydro-geomorphological studies (Mann–Kendall trend test, Șen's slope estimator and the innovative trend method) applied on data from 10 gauging stations located on major tributaries of Trotuș River. Results reveal an overall downward trend of the mean annual streamflow and an increasing trend of the mean annual suspended sediment load. Whereas the decreasing streamflow trend was linked to the diminishing precipitation amounts, the upward trend of suspended sediment load was related to the changes occurring within river channels as a result of flood events.

DMSA-scintigraphy in paediatrics: Is the evaluation of the geometric mean necessary for the calculation of the differential renal function?

2001 ◽  
Vol 40 (04) ◽  
pp. 107-110 ◽  
Author(s):  
B. Roßmüller ◽  
S. Alalp ◽  
S. Fischer ◽  
S. Dresel ◽  
K. Hahn ◽  
...  
Keyword(s):  
Renal Function ◽  
Geometric Mean ◽  
Region Of Interest ◽  
Posterior View ◽  
Renal Abnormality ◽  
Anterior View ◽  
Differential Renal Function ◽  
The Mean ◽  
The Right ◽  
To Receive

SummaryFor assessment of differential renal function (PF) by means of static renal scintigraphy with Tc-99m-dimer-captosuccinic acid (DMSA) the calculation of the geometric mean of counts from the anterior and posterior view is recommended. Aim of this retrospective study was to find out, if the anterior view is necessary to receive an accurate differential renal function by calculating the geometric mean compared to calculating PF using the counts of the posterior view only. Methods: 164 DMSA-scans of 151 children (86 f, 65 m) aged 16 d to 16 a (4.7 ± 3.9 a) were reviewed. The scans were performed using a dual head gamma camera (Picker Prism 2000 XP, low energy ultra high resolution collimator, matrix 256 x 256,300 kcts/view, Zoom: 1.6-2.0). Background corrected values from both kidneys anterior and posterior were obtained. Using region of interest technique PF was calculated using the counts of the dorsal view and compared with the calculated geometric mean [SQR(Ctsdors x Ctsventr]. Results: The differential function of the right kidney was significantly less when compared to the calculation of the geometric mean (p<0.01). The mean difference between the PFgeom and the PFdors was 1.5 ± 1.4%. A difference > 5% (5.0-9.5%) was obtained in only 6/164 scans (3.7%). Three of 6 patients presented with an underestimated PFdors due to dystopic kidneys on the left side in 2 patients and on the right side in one patient. The other 3 patients with a difference >5% did not show any renal abnormality. Conclusion: The calculation of the PF from the posterior view only will give an underestimated value of the right kidney compared to the calculation of the geometric mean. This effect is not relevant for the calculation of the differntial renal function in orthotopic kidneys, so that in these cases the anterior view is not necesssary. However, geometric mean calculation to obtain reliable values for differential renal function should be applied in cases with an obvious anatomical abnormality.

Prince Henri d'Orleans (1867–1901): geographical and botanical exploration between inner Asia and southwest China

1978 ◽  
Vol 8 (4) ◽  
pp. 399-399
Author(s):  
WILLIAM GARDENER
Keyword(s):  
Southwest China ◽  
Western China ◽  
Left Bank ◽  
Inner Asia ◽  
Botanical Exploration ◽  
Western Yunnan ◽  
Westerly Direction ◽  
Chinese Province ◽  
The Right ◽  
North Western

Prince Henri d'Orleans, precluded by French law from serving his country in the profession of arms, had his attention turned early towards exploration. In 1889, accompanied by the experienced traveller Gabriel Bonvalet, he set out from Paris to reach Indo-China overland by way of Central Asia, Tibet and western and south western China. The journey made contributions in the problems of the whereabouts of Lap Nor and the configuration of the then unexplored northern plateau of Tibet; and in botany it produced some species new to science. The party reached Indo-China in 1890. In 1895, having organised an expedition better equipped for topographical survey and for investigations in the fields of natural history and ethnography, Prince Henri set out from Hanoi with the intention of exploring the Mekong through the Chinese province of Yunnan. After proceeding up the left bank of the Salween for a brief part of its course and then alternating between the right and left banks of the Mekong as far up as Tzeku, the party found it advisable to enter Tibet in a north westerly direction through the province of Chamdo and instead crossed the south eastern extremity of the country, the Zayul, by a difficult track which led them to the country of the Hkamti Shans in present day Upper Burma, and thence to India completing a journey of 2000 miles, "1500 of which had been previously untrodden" (Prince Henri). West of the Mekong, the journey established that the Salween, which some geographers had claimed took its rise in or near north western Yunnan, in fact rose well north in Tibet, and that, contrary to previous opinions, the principal headwater of the Irrawaddy rose no further north than latitude 28°30'. Botanical collections were confined to Yunnan, where the tracks permitted mule transport, and they produced a number of species new to science and extended the range of distribution of species already known.

Neural networks approached for modelling river suspended sediment concentration due to tropical storms

2013 ◽  
Vol 11 (4) ◽  
pp. 457-466
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Time Series Data ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Series Data ◽  
Generalized Regression Neural Network ◽  
Event Based

Artificial neural networks are one of the advanced technologies employed in hydrology modelling. This paper investigates the potential of two algorithm networks, the feed forward backpropagation (BP) and generalized regression neural network (GRNN) in comparison with the classical regression for modelling the event-based suspended sediment concentration at Jiasian diversion weir in Southern Taiwan. For this study, the hourly time series data comprised of water discharge, turbidity and suspended sediment concentration during the storm events in the year of 2002 are taken into account in the models. The statistical performances comparison showed that both BP and GRNN are superior to the classical regression in the weir sediment modelling. Additionally, the turbidity was found to be a dominant input variable over the water discharge for suspended sediment concentration estimation. Statistically, both neural network models can be successfully applied for the event-based suspended sediment concentration modelling in the weir studied herein when few data are available.

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