scholarly journals An Assimilation Simulation Approach to Suspended Sediment Concentration in Inland Lakes Using Hybrid Perturbation Generation Method

2021 ◽  
Author(s):  
Fei Guo ◽  
Jingjia Zhang ◽  
A-xing Zhu ◽  
Zhuo Zhang ◽  
Hong Zhang
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Random Perturbation ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Hydrological Simulation ◽  
Simulation Accuracy ◽  
Mean Values ◽  
Inland Lakes ◽  
Perturbation Field

Abstract Suspended sediments, as one of the most important factors affecting the water environment of inland lakes, are closely related to the various pollutants migration and interaction. Thus, the simulation and prediction of suspended sediment concentration is important. Existing studies show that the prediction accuracy of suspended sediment concentration can be effective predicted based on assimilation methods coupled with hydrodynamic models. However, in the process of assimilation of hydrological simulation, the existing perturbation generation methods consider that the perturbation error is a random Gaussian distribution, which does not consider the spatial variation characteristics of errors. In this paper, a new method to generate the perturbation field for assimilation simulation was proposed. This method uses hybrid error to generate perturbation field for assimilation simulation instead of using random error. The proposed approach was validated through its application to assimilation simulation of suspended sediment concentration of Taihu Lake in China, and five assimilation experiments was conducted. The proposed method was compared with existing methods for perturbation field generation. After three days and 72 time steps of assimilation simulation based on hybrid perturbation generation, we found that the proposed assimilation method provided results that were more consistent with buoy-measured data. The accuracy of the two assimilation methods based on hybrid perturbation is improved. Compared with the assimilation method based on random perturbation, the mean values of RMSE(root mean square error) decreased from 9.56 to 8.70 and from 9.55 to 8.68, respectively. The results show that the proposed hybrid perturbation generation method has higher simulation accuracy than other methods. This study shows that the method is effective and provides a new idea for the assimilation simulation of suspended sediment concentration in inland lakes.

scholarly journals Curvas-chave de descargas de sedimentos em suspensão no Baixo São Francisco

2020 ◽  
Vol 13 (3) ◽  
pp. 1248 ◽  
Author(s):  
Solange Cavalcanti de Melo ◽  
José Coelho de Araújo Filho ◽  
Renata Maria Caminha Mendes de Oliveira Carvalho
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Gradual Reduction ◽  
Sao Francisco River ◽  
Sediment Loads ◽  
São Francisco River ◽  
Historical Series ◽  
Suspended Sediment Concentrations

RESUMOO conhecimento da análise quantitativa das concentrações de sedimentos em suspensão transportados pelo rio São Francisco bem como sua relação com as vazões é de muita importância, pois pode auxiliar na identificação dos efeitos da intervenção humana e ou ocasionados pelas condições naturais da região. As regiões a jusante dos barramentos no rio São Francisco apresentam como principal consequência a regularização das vazões e a diminuição das concentrações de sedimentos. O objetivo da pesquisa foi determinar as curvas-chave de sedimentos em suspensão (CCS) nas estações fluviométricas instaladas no Baixo São Francisco (BSF) após a barragem de Xingó. Para o estabelecimento dessas curvas foram utilizados dados de vazão e concentração de sedimentos em suspensão, obtidos do sistema Hidroweb no site da Agência Nacional da Água (ANA) no período de 1999 a 2018. Foram obtidas CCS para todo o trecho do BSF as quais apresentaram bons coeficientes de determinação. Na análise dos dados também foi possível perceber que nos últimos anos, desde 2013 houve redução gradativa das vazões disponibilizadas na barragem de Xingó. Consequentemente, houve também a redução gradativa das cargas de sedimentos em suspensão geradas nas estações de Piranhas, Traipu e Propriá, ou seja, os menores valores já registrados no BSF correspondendo as menores séries históricas tanto de vazão como de sedimentos em suspensão.  Keys curves of sediment discharges in suspension in the Lower São Francisco A B S T R A C TThe knowledge of the quantitative analysis of suspended sediment concentrations carried by the São Francisco River as well as its relation with the flows is of great importance, since it can help in the identification of the effects of human intervention and/or caused by the natural conditions of the region. In the downstream regions of the São Francisco riverbanks, the main consequence was the regularization of flow rates and the reduction of sediment concentrations. The objective of the research was to determine the key curves of suspended sediments (CCS) at the fluviometric stations installed in the lower São Francisco river after Xingó dam. For the evaluation, flow data and suspended sediment concentration were used. These data were obtained from the Hidroweb system on the website of the National Water Agency (ANA) from 1999 to 2018. CCS were plotted for all stretches and presented good coefficients of determination (R2). Based on the analysis of the data it was also possible to notice that in recent years, since 2013 there has been a gradual reduction of the flows available in the Xingó dam. Consequently, there was also a gradual reduction of suspended sediment loads generated at the Piranhas, Traipu and Propriá stations, that is, the lowest values already recorded in lower São Francisco, corresponding to the lower historical series of both discharge and suspended sediments.Keywords: dam, flow, sediments 

scholarly journals Transport Mechanism of Suspended Sediments and Migration Trends of Sediments in the Central Hangzhou Bay

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2189
Author(s):  
Zekun Song ◽  
Weiyong Shi ◽  
Junbiao Zhang ◽  
Hao Hu ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Hangzhou Bay ◽  
The South ◽  
Transport Mode ◽  
Tidal Pumping ◽  
The North

Based on the 2013 field survey data of hydrology, suspended sediments and bottom sediments in the Central Hangzhou Bay, this paper explores the dynamic mechanism of suspended sediments in Hangzhou Bay by employing material flux decomposition. Meanwhile, the migration trends of bed sediments are also investigated by analyzing grain size trends. The results show that during an ebb or flood tide, the hydrograph of suspended sediment concentration of Hangzhou Bay is dominated by an M shape (bimodal), which is attributed primarily to the generation of a soft mud layer and a separate fluid mud layer. Laterally, the distribution of suspended sediment concentration is high in the south and low in the north. From a macroscopic perspective, the net sediment transport in the study area displays a “north-landward and south-seaward” trend, presenting a “C”-shaped transport mode. That is, the sediments are transported from the bay mouth to the bay head on the north side and from the bay head to the bay mouth on the south side. The sediment transports by advection and tidal pumping are predominant, while the sediment transport by vertical circulation makes little contribution to the total sediment transport. Moreover, the sediment transport in the center of the reach area is dominated by advection, whereas that near both sides of the banks is controlled by tidal pumping. The asymmetry of the tides, i.e., flood-dominance in the north and ebb-dominance in the south, is the primary cause of the dynamic mechanism for the overall “C”-shaped transport mode in Hangzhou Bay. Additionally, coupled with the narrow-head wide-mouth geomorphology, Hangzhou Bay remains evolving by south shore silting and north shore scouring.

Dynamics of Suspended Sediments Related to Fine Particles in Lower Mekong River

2013 ◽  
Vol 446-447 ◽  
pp. 1528-1533
Author(s):  
Sarunya Promkotra
Keyword(s):  
Shear Stress ◽  
Flow Velocity ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Fine Particles ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Mekong River ◽  
Fall Velocity ◽  
Stream Discharge

Analytical results are considered the factors of suspended sediment concentration, fall velocity, dimensionless shear stress, transportation rate and stream discharge. As a result of suspended sediments of Loei, Huang and Mekong River, fine particles account for the applicability in sediment deposits. Floating suspended sediments explicit more clay minerals than suspended sediments. Suspended sediment concentration (SSC) in the estuarine of Loei River and Huang River are moderately less than Mekong River. Flow directions of the interconnected rivers to the mainstream-Mekong River lead to the quantity of SSC. Sediment concentrations attain to the dynamic response. Dimensionless shear stress relates to shear velocity, geometry and grain size of particles, and difference of flow velocity. This shear stress is directly comparative to flow velocity and clay mineral concentrations. The transport rate involves in the flow velocity, SSC and depth of the river. Moreover, stream discharge can be presumed by the geometry of the river and topography of sampling locations.

scholarly journals Sampling strategies to estimate suspended sediment concentration for turbidimeter calibration

2017 ◽  
Vol 21 (12) ◽  
pp. 884-889 ◽  
Author(s):  
Leandro Dalbianco ◽  
Rafael Ramon ◽  
Claudia A. P. de Barros ◽  
Jean P. G. Minella ◽  
Gustavo H. Merten ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Rainfall Event ◽  
Sampling Strategies ◽  
Southern Brazil ◽  
Rainfall Events ◽  
Insufficient Amount ◽  
Indirect Relationship

ABSTRACT The influx of sediments carried by rivers can be measured continuously using a turbidimeter through the indirect relationship between turbidity and suspended sediment concentration (SSC). However, this process is dependent on obtaining water samples with suspended sediments to calibrate the turbidimeter. Sampling can be carried out through different methods, resulting in errors and uncertainties in estimating the SSC. Four different possibilities for the composition of the calibration curve were tested in order to evaluate the effectiveness of the turbidimeter calibration for different sampling strategies. The study was conducted in 2012 and 2013 in two catchments in southern Brazil that had a strong sediment yield impact. The results indicate that sampling during rainfall events generate a significant and representative SSC for the turbidimeter calibration. The use of an integrating sampler for synthetic samples provides an effective calibration, but overestimates SSC compared to calibration from rainfall event sampling. The samples collected at fixed intervals - weekly and daily - generated an insufficient amount of data and are not representative of real sediment concentrations of the catchments.

scholarly journals Indirect Estimation of Flow and Suspended-sediment Concentration and Load in Small Mountain Streams: an Exploratory Study in Ribeira Seca Stream, Madeira Island

2021 ◽  
Vol 16 ◽  
Keyword(s):  
Suspended Sediment ◽  
Exploratory Study ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
Measurement Campaign ◽  
Indirect Determination ◽  
Madeira Island ◽  
The North

The aim of this study was to assess the applicability of indirect techniques for streamflow and suspended sediment concentration estimation and their use in the calculation of suspended sediment transport rate in the small mountain watersheds of Madeira Island, Portugal. Emphasis was given to the application of salt dilution gauging to the indirect determination of the flow rate and the use of water turbidity data to estimate the concentration of suspended sediments. The field and laboratory work carried out are briefly described, and the main experimental results and the field data from the short measurement campaign performed in the Ribeira Seca stream in Faial, on the north side of the island, are presented and discussed. Whilst the measurement campaign carried out was temporally and spatially limited, it was pioneering for Madeira and allowed to verify the applicability of the indirect hydrometric and sedimentometric techniques used in this exploratory study.

scholarly journals Prediction and classification of suspended sediment and zooplankton signals from acoustic Doppler current profiler backscatter data using artificial neural networks

2021 ◽  
Vol 944 (1) ◽  
pp. 012014
Author(s):  
A Dwinovantyo ◽  
S Solikin ◽  
H M Manik ◽  
T Prartono ◽  
Susilohadi
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Acoustic Doppler Current Profiler ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Optimal Number ◽  
Environmental Data ◽  
Zooplankton Abundance ◽  
Current Profiler ◽  
Artificial Neural

Abstract Characterization of each underwater object has its challenges, especially for small objects. The process of quantifying acoustic signals for these small objects can be done using high-frequency hydroacoustic instruments such as an acoustic Doppler current profiler (ADCP) combined with the artificial intelligence (AI) technique. This paper presents an artificial neural network (ANN) methodology for classifying an object from acoustic and environmental data in the water column. In particular, the methodology was tuned for the recognition of suspended sediments and zooplankton. Suspended sediment concentration and zooplankton abundance, which extracted from ADCP acoustic data, were used as input in the backpropagation method along with other environmental data such as effects of tides, currents, and vertical velocity. The classifier used an optimal number of neurons in the hidden layer and a feature selection based on a genetic algorithm. The ANN method was also used to estimate the suspended sediment concentration in the future. This study provided new implications for predicting and classifying suspended sediment and zooplankton using the ADCP instrument. The proposed methodology allowed us to identify the objects with an accuracy of more than 95%.

scholarly journals Monitoring of seasonally variability and movement of suspended sediment concentration along Thiruvananthapuram coast using OLI sensor

2018 ◽  
Author(s):  
Bismay Ranjan Tripathy ◽  
Kaliraj Seenipandi ◽  
Haroon Sajjad ◽  
Pawan Kumar Joshi ◽  
Bhagwan Singh Chaudhary ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Analysis Data ◽  
Sediment Concentration ◽  
Landsat 8 ◽  
Wave Direction ◽  
High Concentration ◽  
Littoral Current ◽  
Lower Depth

Abstract. In the recent decades hydrologists, geologists, and stream ecologists have shown substantial interest in analyzing suspended sediments in water. Extracting information like suspended sediment concentration (SSC) in coastal waters is very important for assessment and monitoring of coastal settings and their effects on their ecology. This article demonstrates importance of Landsat 8 Operational Land Imager (OLI) for monitoring seasonal variation in SSC and movement (pre and post monsoon) along Thiruvananthapuram Coast in India. The data was converted into marine reflectance after correcting due atmospheric errors. SSC was extracted using spectral analysis data analysis. Movement of SSC was monitored using wave direction and significant wave height data. The results revealed that the SSC decreased rapidly with the increase in distance from the beach and depth of the seabed. Wave with higher frequency in deeper water caused sparely circulation of sediments and their concentration at the lower depth in high bathymetry. Thus, the suspended sediments were indirectly proportional to bathymetry and distance from the shoreline and directly proportion to wave direction and littoral current at off-shore. High concentration of sediments was found to be accumulated at shallow depth (

Prediction of Suspended Sediments in a Hyper – Concentrated River Using Neural Networks

2014 ◽  
Vol 567 ◽  
pp. 122-127
Author(s):  
Raza Ul Mustafa Muhammad ◽  
Ahmad Safwan Abu Bakar ◽  
Mohamed Hasnain Isa ◽  
Khamaruzaman Wan Yusof
Keyword(s):  
Prediction Model ◽  
Suspended Sediment ◽  
Basis Function ◽  
Suspended Sediment Concentration ◽  
Prediction Models ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Coefficient Of Determination ◽  
Neural Network Modeling ◽  
Discharge Data

Prediction of suspended sediment concentration in hyper-concentrated rivers is a crucial task in modeling and designing of hydraulic structures such as dams, reservoirs, barrages and water intake inlets. In this study, suspended sediment concentration in Kinta River has been predicted using radial basis function (RBF) neural network modeling technique. Time series of suspended sediments and stream discharge data from 1992 to 1995 are used in the training and testing stages of the model. The data were divided into two sections based on the model stages as training and testing. The Thin Plate Spline (TPS) basis function was used to establish TPS - RBF prediction model. The input neurons were selected based on previous studies about the suspended sediment prediction models. The number of hidden neurons was determined by trial and error method. The spread of the basis function was determined by normalization method. The performance of the prediction model was evaluated using three statistical performance measures namely root mean square error (RMSE), coefficient of efficiency (CE) and coefficient of determination (R2). The results showed that the TPS – RBF model predicted the suspended sediment values close to the observed data. The statistics of the model showed that the prediction model performed very well and produced R2 values close to one in both training and testing stages.

scholarly journals SUSPENDED SEDIMENT CONCENTRATION IN THE SURF ZONE

1988 ◽  
Vol 1 (21) ◽  
pp. 123 ◽  
Author(s):  
Makoto Ifuku ◽  
Tadao Kakinuma
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Surf Zone ◽  
Diffusion Theory ◽  
Sediment Concentration ◽  
Finite Amplitude ◽  
Reference Level ◽  
Sand Particle ◽  
Phase Lag ◽  
Mean Values

The water particle velocity,the pressure fluctuation and suspended sediment concentration near the bottom were measured in the surf zone. Data were obtained on the mean sediment concentration, phase lag between onshore velocity and suspended sediment concentration. The near-bottom velocity distributions under finite amplitude waves were calculated on the basis of the turbulent boundary layer theory by using timeindependent/ dependent eddy viscosities and Prandtl mixing length theory. The concentrations at reference level were estimated from the Kalkanis' theory using the velocity value at the top of a sand particle and the distributions of suspended sediment concentration were calculated on the basis of the turbulent diffusion theory by using time-independent/ dependent diffusion coefficients. The computed mean values of the suspended sediment concentration agree with those observed by Noda, the authors and Nielsen and those measured by Deigaard et al.. The computed phase lag agrees well with observed by the authors.

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