scholarly journals Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Angga Dwinovantyo ◽  
Henry M. Manik ◽  
Tri Prartono ◽  
Susilohadi Susilohadi

The application of Acoustic Doppler Current Profiler (ADCP) can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC) from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient (r) 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.

2021 ◽  
Vol 944 (1) ◽  
pp. 012014
Author(s):  
A Dwinovantyo ◽  
S Solikin ◽  
H M Manik ◽  
T Prartono ◽  
Susilohadi

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%.


Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 981 ◽  
Author(s):  
Zacharie Sirabahenda ◽  
André St-Hilaire ◽  
Simon C. Courtenay ◽  
Michael R. van den Heuvel

The increased soil loss in an agricultural watershed raises challengers for river water quality and a reliable automated monitoring for suspended sediment concentrations (SSC) is crucial to evaluate sediment budgets variation in systems. The aims of this study were (1) to test if an acoustic doppler current profiler (ADCP) would give similar results to turbidity probe measurements as a high frequency monitoring tool for suspended sediment; and (2) to analyze the relationship between sediment drivers and SSC in a typical agricultural drainage basin. The acoustic and optical backscatter sensors were used to collect SSC data during the ice-free seasons of four consecutive years in the Dunk River (PEI, Canada). The slopes of the relationships between the two SSC indirect measurements were not significantly different than 1. Correlations between SSC and hydro-meteorological variables showed that the high SSC values were more associated with the streamflow and water velocity than precipitation. This study highlighted the great potential of ADCP for the continuous monitoring of suspended sediment in an agricultural watershed. For summer periods the prevalence of clockwise hysteresis (74.1% of measured rainstorm events with SSC > 25 mg L−1) appeared related to rainstorm behaviors.


2011 ◽  
Vol 8 (4) ◽  
pp. 1601-1630 ◽  
Author(s):  
P. Ghaffari ◽  
J. Azizpour ◽  
M. Noranian ◽  
V. Chegini ◽  
V. Tavakoli ◽  
...  

Abstract. Data sets of Acoustic Doppler Current Profiler (ADCP) backscatter intensities (ABS) were used to evaluate suspended sediment concentrations (SSC) in the Mahshahr Channel (MC) of the Persian Gulf. Since the echo intensity is closely related to turbidity in water, the ADCP may be a promising tool to monitor the sediment transport. The low susceptibility of the acoustic backscatter to bio-fouling and the ADCP provision of current profiles as well as sediment time series makes this monitoring method more advantageous compared with the traditional methods. Time series of ADCP backscatter intensity profiles were used for improving temporal resolution of SSC estimates. Backscatter and traditional observational data were separated into two segments. The first part was utilized for calibrating the backscatter data and attributing the intensity to suspended particle concentrations and using the second part acoustic intensities were validated. Acoustic based SSC estimates are slightly underestimated in comparison with traditional water sample based SSC values, but still there is good agreement between acoustic SSC and traditional observations. Results illustrate a rather high correlation between lab based and acoustic based particles in suspension (R2 = 88 %). Additionally measurements reveal the domination of a semidiurnal ebb asymmetric system in the MC. Tidal currents provide the main energy source for particle resuspension and transport. Maximum suspended load concentrations are evident in ebb tides, while the currents strengths are enough to refloat loads from the bed. In general spring tides show higher SSC values compared with neap tides in the study area.


2020 ◽  
Vol 13 (3) ◽  
pp. 1248 ◽  
Author(s):  
Solange Cavalcanti de Melo ◽  
José Coelho de Araújo Filho ◽  
Renata Maria Caminha Mendes de Oliveira Carvalho

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 


2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Henry Munandar Manik ◽  
Randi Firdaus

Tidung Island, located near Jakarta Bay, is a tourism and conservation area. It is necessary to keep these seawaters unpolluted. To calculate the level of pollution, it is necessary to know the sediment concentration. Quantifying concentration suspended sediment is important for knowledge of sediment transport. Researchers usually use water sample analysis and optical method for quantifying suspended sediment in seawater. Less accuracies of these methods are due to under sample of seawater and the existence of biological fouling. One promising method to measure concentration of suspended sediment is using Acoustic Doppler Current Profiler (ADCP). ADCP is usually used by oceanographer and hydrographer to measure ocean current. In this research, ADCP with 300 kHz operating frequency was used effectively to measure suspended sediment concentration (SSC) and ocean current simultaneously. The echo intensity received from suspended sediment was computed using sonar equations to quantify SSC. The empirical equation between echo intensity and SSC was found. The SSC value obtained by ADCP was also compared with in situ measurement. The result showed that quantified SSC value obtained by ADCP was nearly equal with SSC obtained from in situ measurement with coefficient correlation of 0.98. The high concentration ranged from 55 mg/L to 80 mg/L at the surface layer to a depth 12 m, moderate concentration ranged from 45 mg/L to 55 mg/L at a depth 12 m to 40 m, and low concentration less than 45 mg/L at a depth greater than 40 m. The distribution of SSC was correlated with ocean current condition. In small currents, suspended solids will settle faster so that the concentration in the water column will decrease. Conversely, if the velocity is high, suspended solids will continue to float carried by the current in the water column so that the concentration is high.


Author(s):  
A. T. Buller

SynopsisDuring periods of sustained moderate river discharge and quiescent marine conditions little external suspended sediment enters the estuarine circulation of the Tay. That material which is in suspension is largely derived from the estuary margins where tidal currents superimposed by wind-induced waves are competent to resuspend fine material from the surface of the ‘mud’ flats and erode bedded silts from the incised banks of minor channels and runnels draining them. The quantities of this sediment entering the system are largely determined by tidal state and amplitude, as well as wind velocity.On spring tides the flats are entirely covered at high water, and dry out completely at low water. The volume of water and its areal coverage at high tide ensures that, during the ebb, water charged with high concentrations of suspended sediment is directed from the fiats into the surface and middepth waters of the main channel. This process acting along the 20 km length of the channel flanking the ‘mud’ flats, combined with the low tide ‘ponding effect’ caused by the tide flooding from the sea while the upper estuarine water is still ebbing, results in the cumulative formation of a zone of high suspended sediment concentrations (turbidity maximum). As the flood tide becomes fully established the zone is diluted and dispersed. During neap tides the same processes operate, but because a smaller area of the flats is covered at high water and uncovered at low water, and because neap tidal current speeds are lower than those for spring tides, two proportionally weaker zones are recognised.Following periods of sustained moderate river discharge, quiet sea conditions and calm weather, suspended sediment concentrations in the Tay are negligible irrespective of tidal state or amplitude.


2008 ◽  
Vol 52 ◽  
pp. 949-954 ◽  
Author(s):  
Kiyoshi KAWANISHI ◽  
Tomoya YOKOYAMA ◽  
Masamitsu MIZUNO ◽  
Shoji FUKUOKA

RBRH ◽  
2021 ◽  
Vol 26 ◽  
Author(s):  
Marcio Sousa da Silva ◽  
Rosane Lopes Cavalcante ◽  
Pedro Walfir Martins e Souza Filho ◽  
Renato Oliveira da Silva Júnior ◽  
Paulo Rógenes Pontes ◽  
...  

ABSTRACT Understanding the hydrosedimentological dynamics of tropical rivers is a challenge in the Amazon due to its remote and difficult-to-access areas. This study was based on data collected from 16 hydrosedimentological control sections in the 6 subbasins that make up the Itacaiúnas River Watershed (IRW), with 4 annual campaigns (high water levels, rising water levels, falling water levels, low water levels) between 2015 and 2019, with the aim of constructing and comparing sediment rating curves and sediment yield. The data at the mouth of the IRW revealed that the rainy season is responsible for 93% of liquid discharges (Q) with an average of 1460.88 m3/s and for 98% of suspended sediment discharges (SSQ) with an average of 5864.15 tons/day. Suspended sediment concentrations (SSCs) are low to moderate (50 to 150 mg/l). The curves encompassing all the data showed R2 values (0.92 to 0.99) greater than the curves with only the values of the rainy or dry season, indicating a good fit of the power equation to the SSQ and Q data for all sections studied. Higher values of coefficients a and b show areas of greater sediment production and deforestation, as well as areas with new sources of sediment and preserved forest.


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