Sediment acoustic index method for computing continuous suspended-sediment concentrations

Landers, Mark N.; Straub, Timothy D.; Wood, Molly S.; Domański, Marian

doi:10.3133/tm3c5

Cited by 27 publications

(24 citation statements)

References 26 publications

(19 reference statements)

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“…represents sound absorption by sediment suspended in the water; if concentration varies spatially, Equation (4) would need to be modified to capture this variation. Guidance on choosing both coefficients can be found in Landers et al (2016). For the sediment concentrations (ranging 20 to 1000 mg•L -1 ), water temperatures and salinities considered in this study, the corrections arising from both modes of attenuation were small enough to be negligible, in part because of the small range (15 cm) associated with the ADV used here.…”

Section: Acoustic Backscatter Methods For Estimation Of Sscmentioning

confidence: 99%

“…The sediment correction factor is unknown here, but previous research indicates that it should be O(1 dB/m) and also constant, if sediment characteristics are constant (Landers et al 2016). This implies that the two-way correction in Equation (4) should be ~0.3 dB.…”

Section: Acoustic Estimates Of Sscmentioning

confidence: 96%

“…where Bw = 3.38e-6, f is the instrument frequency in kHz, and = 21.9 * 10 and T is water temperature in degrees C (Landers et al 2016). While T did vary during the measurement campaign, its influence on the water correction factor is negligible, and this factor was evaluated for a constant temperature of 10 degrees C. The resulting water correction factor is 1.31 dB/m, and with a range of 0.15 m, the resulting two-way correction for water attenuation is 0.4 dB.…”

Section: Acoustic Estimates Of Sscmentioning

confidence: 99%

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Acoustic Doppler Velocimeter Backscatter for Quantification of Suspended Sediment Concentration in South San Francisco Bay

Öztürk

Work

2017

Int. Conf. Coastal. Eng.

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A data set was acquired on a shallow mudflat in south San Francisco Bay that featured simultaneous, co-located optical and acoustic sensors for subsequent estimation of suspended sediment concentrations (SSC). The optical turbidity sensor output was converted to SSC via an empirical relation derived at a nearby site using bottle sample estimates of SSC. The acoustic data was obtained using an acoustic Doppler velocimeter. Backscatter and noise were combined to develop another empirical relation between the optical estimates of SSC and the relative backscatter from the acoustic velocimeter. The optical and acoustic approaches both reproduced similar general trends in the data and have merit. Some seasonal variation in the dataset was evident, with the two methods differing by greater or lesser amounts depending on which portion of the record was examined. It is hypothesized that this is the result of flocculation, affecting the two signals by different degrees, and that the significance or mechanism of the flocculation has some seasonal variability. In the earlier portion of the record (March), there is a clear difference that appears in the acoustic approach between ebb and flood periods, and this is not evident later in the record (May). The acoustic method has promise but it appears that characteristics of flocs that form and break apart may need to be accounted for to improve the power of the method. This may also be true of the optical method: both methods involve assuming that the sediment characteristics (size, size distribution, and shape) are constant

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Section: Acoustic Backscatter Methods For Estimation Of Sscmentioning

confidence: 99%

Section: Acoustic Estimates Of Sscmentioning

confidence: 96%

Section: Acoustic Estimates Of Sscmentioning

confidence: 99%

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Acoustic Doppler Velocimeter Backscatter for Quantification of Suspended Sediment Concentration in South San Francisco Bay

Öztürk

Work

2017

Int. Conf. Coastal. Eng.

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“…Research has focused (using down-, side-or up-looking ADCP deployment) on the relation of suspended sediment and corrected backscatter (Thorne et al, 1993(Thorne et al, , 1998Reichel and Nachtnebel, 1994;Holdaway et al, 1999;Thorne and Hanes, 2002;Gartner, 2004;Wall et al, 2006;Topping et al, 2007;Deines, 1999;Szupiany et al, 2009;Hanes, 2012;Guerrero et al, 2013Guerrero et al, , 2016Latosinski et al, 2014;Thorne and Hurther, 2014;Landers et al, 2016;Manaster et al, 2016;Venditti et al, 2016;Topping and Wright, 2016;Mullison, 2017;Hackney et al, 2018), acoustic attenuation and scattering properties (Thorne and Meral, 2008;Wright, et al, 2010;Sassi et al, 2012;Moate and Thorne, 2013;Moore et al, 2013;Agrawal and Hanes, 2015;Hanes, 2016;Topping and Wright, 2016;Haught et al, 2017), and acoustic scattering by suspended flocculating sediments (Thorne and Hurther, 2014;Vincent and McDonald, 2015;Thomas et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Estimating sand concentrations using ADCP‐based acoustic inversion in a large fluvial system characterized by bi‐modal suspended‐sediment distributions

Szupiany

Weibel

Guerrero

et al. 2019

Earth Surf Processes Landf

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Quantifying sediment flux within rivers is a challenge for many disciplines due, mainly, to difficulties inherent to traditional sediment sampling methods. These methods are operationally complex, high cost, and high risk. Additionally, the resulting data provide a low spatial and temporal resolution estimate of the total sediment flux, which has impeded advances in the understanding of the hydro‐geomorphic characteristics of rivers. Acoustic technologies have been recognized as a leading tool for increasing the resolution of sediment data by relating their echo intensity level measurements to suspended sediment. Further effort is required to robustly test and develop these techniques across a wide range of conditions found in natural river systems. This article aims to evaluate the application of acoustic inversion techniques using commercially available, down‐looking acoustic Doppler current profilers (ADCPs) in quantifying suspended sediment in a large sand bed river with varying bi‐modal particle size distributions, wash load and suspended‐sand ratios, and water stages. To achieve this objective, suspended sediment was physically sampled along the Paraná River, Argentina, under various hydro‐sedimentological regimes. Two ADCPs emitting different sound frequencies were used to simultaneously profile echo intensity level within the water column. Using the sonar equation, calibrations were determined between suspended‐sand concentrations and acoustic backscatter to solve the inverse problem. The study also analyzed the roles played by each term of the sonar equation, such as ADCP frequency, power supply, instrument constants, and particle size distributions typically found in sand bed rivers, on sediment attenuation and backscatter. Calibrations were successfully developed between corrected backscatter and suspended‐sand concentrations for all sites and ADCP frequencies, resulting in mean suspended‐sand concentration estimates within about 40% of the mean sampled concentrations. Noise values, calculated using the sonar equation and sediment sample characteristics, were fairly constant across evaluations, suggesting that they could be applied to other sand bed rivers. © 2018 John Wiley & Sons, Ltd.

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“…They use the measured shift in the apparent frequency of transmitted sound waves to compute a three-dimensional (3-D) flow velocity. The strength of the acoustic return signal has also been used as a proxy for sediment concentration in water systems [17,[27][28][29][30][31]. The basic principle for the measurement of suspended sediments is that acoustic waves passing through a water-sediment mixture will scatter and attenuate as a function of sediment, fluid, and instrument characteristics.…”

Section: Introductionmentioning

confidence: 99%

Sediment Size Effects in Acoustic Doppler Velocimeter-Derived Estimates of Suspended Sediment Concentration

Öztürk

2017

Water

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Backscatter output from a 10 MHz acoustic Doppler velocimeter (ADV) was used to quantify suspended sediment concentrations in a laboratory setting using sand-sized particles. The experiments included (a) well-sorted sand samples ranging in size from 0.112 to 0.420 mm, obtained by the sieving of construction sand, (b) different, known mixtures of these well-sorted fractions, and (c) sieved natural beach sand with median sizes ranging from 0.112 to 0.325 mm. The tested concentrations ranged from 25 to 3000 mg·L −1 . The backscatter output was empirically related to concentration and sediment size, and when non-dimensionalized by acoustic wavelength, a dimensionless sediment size gradation coefficient. Size-dependent upper and lower bounds on measurable concentrations were also established empirically. The range of measurable conditions is broad enough to make the approach useful for sand sizes and concentrations commonly encountered in nature. A new method is proposed to determine concentrations in cases of mixed-size sediment suspensions when only calibration data for well-sorted constituent sands are available. This approach could potentially allow better estimates when the suspended load is derived from but is not fully representative of the bed material, and when the size characteristics of the suspended material are varying in time over the period of interest. Differences in results between the construction and beach sands suggest that sediment shape may also need to be considered, and point to the importance of calibrating to sediments encountered at the site of interest.

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Sediment acoustic index method for computing continuous suspended-sediment concentrations

Cited by 27 publications

References 26 publications

Acoustic Doppler Velocimeter Backscatter for Quantification of Suspended Sediment Concentration in South San Francisco Bay

Acoustic Doppler Velocimeter Backscatter for Quantification of Suspended Sediment Concentration in South San Francisco Bay

Estimating sand concentrations using ADCP‐based acoustic inversion in a large fluvial system characterized by bi‐modal suspended‐sediment distributions

Sediment Size Effects in Acoustic Doppler Velocimeter-Derived Estimates of Suspended Sediment Concentration

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