Suspended‐sediment measurements in a fluvial environment using acoustic backscatter

2007 ◽  
Vol 121 (5) ◽  
pp. 3126-3126
Author(s):  
Wayne O. Carpenter ◽  
James P. Chambers ◽  
Christopher K. Smith ◽  
Daniel G. Wren ◽  
Roger A. Kuhnle
Keyword(s):  
Suspended Sediment ◽  
Acoustic Backscatter

Acoustic Inversion Method for Profiling Suspended Sediment Concentration

2014 ◽  
Vol 687-691 ◽  
pp. 3980-3983
Author(s):  
Jun Xi Shi ◽  
Min Zhu ◽  
Yan Bo Wu ◽  
Xing Tao Sun
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Acoustic Backscatter ◽  
Inversion Method ◽  
Dual Frequency ◽  
Frequency Method ◽  
Backscatter Signal ◽  
Size Profile ◽  
Acoustic Inversion

The concentration of suspended sediment is an important parameter for the research of sediment transport. Acoustic backscatter technique has been employed to measure the concentration of suspended sediment recently. It is an inversion problem to measure the concentration from the backscatter signal. In this paper, an improved dual-frequency method is proposed for the concentration inversion of suspension sediment. It is an explicit solution with much lower computational complexity than the commonly used iterative method and with no requirement of known and constant particle size profile compared to the basic dual-frequency method.

Estimating instantaneous concentration of suspended sediment using acoustic backscatter from an ADV

2019 ◽  
Vol 34 (5) ◽  
pp. 422-431
Author(s):  
Wenjie Li ◽  
Shengfa Yang ◽  
Wei Yang ◽  
Yi Xiao ◽  
Xuhui Fu ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Acoustic Backscatter ◽  
Instantaneous Concentration

Effect of clay content on Acoustic Doppler Velocimeter backscatter for suspended sediment concentration measurements

2021 ◽  
Author(s):  
Akın Aras ◽  
Cihan Sahin
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Experimental Studies ◽  
Clay Content ◽  
Sediment Concentration ◽  
Acoustic Backscatter ◽  
Doppler Velocity ◽  
Clay Material ◽  
Sediment Distribution ◽  
Wide Range

<p>The capability of ADVs (Acoustic Doppler Velocimeters) to estimate suspended sediment concentration (SSC) has been widely investigated using commercial glass microspheres of the same size or well-sorted fractions in experimental studies. In the natural environment, sediment samples may be composed of different types of sediments having various types of grain size distribution.</p><p>This study aims to analyze experimentally the effect of clay ratio in sediment content on acoustic response. Modification of scattering and attenuation characteristics for different clay ratios is evaluated theoretically. In laboratory experiments, four different sediment mixtures constituting non-cohesive sand and cohesive clay materials were prepared with clay ratios of 0, 5, 10 and 15% by dry mass. A-10 MHz acoustic Doppler velocity profiler (ADVP, The Nortek Vectrino Profiler) was used in controlled laboratory environments under a wide range of concentration conditions up to 10 g/L. Acoustic backscatter measurements were made by immersing the ADVP in a well-mixed circulation tank filled with mixtures with known concentration and sediment composition. The backscattered signals were recorded at 100 Hz, from which 1.5-min ensemble averages were obtained. For each sediment mixture, calibration curves representing the relationship between SSC and acoustic backscatter were obtained based on the sonar equation. Acoustic estimates of suspended sediment parameters obtained for mixtures with different clay contents are compared to identify the effect of increasing clay content on the acoustic signal.</p><p>The experimental results showed that the slope of the calibration curve decreases with increasing validity range as the clay ratio of the mixture increases. Under the fixed SSC condition, the backscatter strength is greater for the mixture with a lower clay ratio. The theoretical analysis indicated that changing clay content modifies the scattering and attenuation properties compared to the mono-size suspension with the same mean size. Introducing clay material in a mixture affects the scattering properties more significantly than the attenuation properties. Therefore, information on the form of the sediment distribution and the sorting of sediments in suspension is crucial for acoustic estimates of suspended sediment parameters.</p><p>Acknowledgments</p><p>This research is supported by the Scientific and Technological Research Council of Turkey (TUBITAK) with project number 218M428.</p>

Observations of suspended sediment stratification from acoustic backscatter in muddy environments

2013 ◽  
Vol 336 ◽  
pp. 24-32 ◽  
Author(s):  
Cihan Sahin ◽  
Ilgar Safak ◽  
Tian-Jian Hsu ◽  
Alexandru Sheremet
Keyword(s):  
Suspended Sediment ◽  
Acoustic Backscatter ◽  
Sediment Stratification

Monitoring suspended sediment plumes by optical and acoustical methods with application to sand capping

2000 ◽  
Vol 27 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Paul F Hamblin ◽  
David Z Zhu ◽  
Fausto Chiocchio ◽  
Cheng He ◽  
Murray N Charlton
Keyword(s):  
Suspended Sediment ◽  
Bottom Sediments ◽  
Quantitative Estimation ◽  
Three Dimensional ◽  
Pilot Scale ◽  
Optical Measurements ◽  
Acoustic Backscatter ◽  
Density Current ◽  
Dense Network ◽  
Sediment Remediation

There is a need to rapidly survey plumes of suspended sediment and to determine the quantity and transport of disturbed material that might arise from industrial and remedial activities in lakes and harbours. The example of sand capping of contaminated bottom sediments is used to illustrate the methodology. Capping of contaminated bottom sediments is one strategy for immobilizing contaminants. In a pilot-scale project, a 0.34 m thick cap of clean sand was deposited over a one hectare area in Hamilton Harbour. The objective of this study was to determine if in-place sediments could be disturbed by the capping operation. In the first of three approaches, the suspended sediment plumes created during the capping operation were monitored for evidence of suspension of bottom materials with underwater acoustic and optical profilers and other moored instruments. In-lake calibration of the instrumentation was based on the collection of over 300 grab samples. Three-dimensional rendering of a dense network of acoustic backscatter profiles revealed that there was no evidence that bottom sediment was resuspended. The density current flowing downslope close to the bottom caused by the capping material was examined and found too weak to erode bottom sediments. Finally, a quantitative estimation of the amount of sediment suspended in the plumes indicated little evidence for resuspension of in-place sediments. The methodology developed could also be applied to estimate the concentration and quantities of contaminants in sediments suspended by other remedial activities such as dredging. Key words: suspended sediment plumes, underwater acoustics, optical measurements, sediment remediation, harbours, lakes.

scholarly journals COUPLED WAVE-BED DYNAMICS, ATCHAFALAYA SHELF, LOUISIANA

2012 ◽  
Vol 1 (33) ◽  
pp. 116
Author(s):  
Cihan Sahin ◽  
Ilgar Safak ◽  
Alexandru Sheremet
Keyword(s):  
Shear Stress ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Critical Shear Stress ◽  
Flow Characteristics ◽  
Sediment Concentration ◽  
Density Variation ◽  
Acoustic Backscatter ◽  
Concentration Profiles ◽  
Fluid Mud

Observations of waves, currents, suspended sediment concentration and acoustic backscatter are used to re-investigate the interaction between the combined wave-current flow and cohesive sediments on the muddy Atchafalaya inner shelf. Observations support the previously proposed bed reworking cycle by waves of mobilization and resuspension of bed sediment, erosion, deposition with fluid mud formation and consolidation. Suspended sediment concentration profiles are estimated based on the acoustic backscatter of a current profiler. A one-dimensional vertical bottom boundary model is used to reconstruct the vertical structure of the flow characteristics, and estimate parameters difficult to observe directly, such as bottom shear stress. Estimated bed position, concentration profiles and computed bottom stresses remarkably support the previous findings on the bottom stress-resuspension relation, critical shear stress for erosion and bed density variation throughout a storm.

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