Multi-frequency acoustics for suspended sediment studies: an application in the Parana River

Guerrero, Massimo; Szupiany, R. N.; Latosinski, F.

doi:10.1080/00221686.2013.849296

Cited by 46 publications

(32 citation statements)

References 28 publications

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“…Following the modeling approach as presented in Guerrero et al [13], we used the single fraction total-load formula by Engelund and Hansen, with 0.26 mm grain size to represent sediment from the river bed and a calibration factor of 0.2. This factor matches the average observed sand concentration loads of 6 mg/L at a discharge of about 14,300 m 3 /s [23].We used a constant bed roughness value throughout the modeling domain of Manning equal to 0.03, corresponding to a Gaukler-Strickler value of 33. At the downstream boundary of the model, we imposed a stage-discharge relationship based on local water level measurements and discharges measured at station Chapeton (taken from Hydrological Integrated Data Base BDHI from the National Subsecretary of Water Resources, Argentina).…”

Section: Hydrodynamic and Morphodynamic Model Settingsmentioning

confidence: 89%

“…Table 2 gives a comparison between simulated and measured flow velocities in five cross-sections (XS in Figure 4b) and in the thalweg longitudinal track by using an acoustic Doppler current profiler (ADCP) during a field campaign in 2009 with a discharge of 13,600 m 3 /s (for further details about this campaign refer to [19]). Figure 6a shows a map of the computed sediment concentration for a discharge of 14,300 m 3 /s that correspond to the flow discharge measured during a field campaign in 2010 using ADCPs [23]. In that campaign, suspended sediment and bed samples and acoustic backscatter profiling at two different frequencies were applied eventually inferring the concentration field in the downstream bifurcation (cross-section indicated in Figure 6a) of sediment suspended from the river bed.…”

Section: Hydro-morphodynamic Validation Of Model Resultsmentioning

confidence: 99%

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Optimizing Dredge-and-Dump Activities for River Navigability Using a Hydro-Morphodynamic Model

Paarlberg

Guerrero

Huthoff

et al. 2015

Water

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Worldwide, significant dredging activities of riverbed sediment are employed to ensure that freight transportation on rivers can continue year-round. Imbalances of sediment budget may produce relevant impacts regarding river morphology and related environmental services. This study shows that hydro-morphodynamic modeling tools can be used to optimize dredge-and-dump activities and, at the same time, mitigate problems deriving from these activities in rivers. As a case study, we focused on dredging activities on the Lower Parana River, Argentina. Navigation on this river is of crucial importance to the economies of the bordering countries, hence, each year significant dredging activities are employed. To estimate dredging loads under different strategies, a 25 km river reach of the Parana River was modeled using the Delft3D-modelling suite by Deltares. The Netherlands, to simulate flow-sediment interactions in a quasi-steady and uncoupled approach. Impacts of dredging activities were explicitly included. Different dredge-and-dump strategies included variations in dredging over-depth (clearance) and variations in dumping locations. Our results indicate that dredge-and-dump strategies can be targeted to stimulate natural processes that improve the depth and stability of the navigation channel and to counteract unwanted bed level responses in the long-medium term. A ~40% reduction in dredging effort could be achieved by moving the dredged material to distant locations in the secondary channel rather than dumping to the side of the waterway in the main channel. OPEN ACCESSWater 2015, 7 3944

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Section: Hydrodynamic and Morphodynamic Model Settingsmentioning

confidence: 89%

Section: Hydro-morphodynamic Validation Of Model Resultsmentioning

confidence: 99%

Optimizing Dredge-and-Dump Activities for River Navigability Using a Hydro-Morphodynamic Model

Paarlberg

Guerrero

Huthoff

et al. 2015

Water

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“…This occurrence was exploited in previous studies by using a single frequency ADCP working at 1200 and 600 kHz, which produced reliable correlations between sand concentrations and measured echo levels [15], and between mean grain sizes of suspended sand and the ratios of echoes for those two frequencies [13].…”

Section: Implications Of the Acoustic Features Assessed From The Obsementioning

confidence: 99%

“…The viscous attenuation coefficient for a heterogeneous sample with a given PSD was evaluated as reported in Equation (13) [18] that includes formulations due to Urick [40] reported in Equations (9)- (12):…”

Section: Acoustic Theorymentioning

confidence: 99%

“…Aiming to guide ADCP users in classifying an actual case study by the acoustic method to be applied for the indirect measurement of sediment transport, our objective was to investigate the dependence of acoustic properties (i.e., backscatter and sound attenuation) on the variation of suspended particles concentration and PSD sampled in the water column at two large rivers. Although excellent studies already exist [19][20][21][22][23][24][25], which aim to clarify these relationships, practical applications are mainly focused on a specific investigated case study that bore out an ADCP specific method [13,15,18,22]. Therefore, our aim was to give an answer on the practical need of evaluating the applicability of different acoustic methods.…”

Section: Introductionmentioning

confidence: 99%

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The Acoustic Properties of Suspended Sediment in Large Rivers: Consequences on ADCP Methods Applicability

Guerrero

Rüther

Szupiany

et al. 2016

Water

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Abstract:The use of echo-levels from Acoustic Doppler Current Profiler (ADCP) recordings has become more and more common for estimating suspended bed-material and wash loads in rivers over the last decade. Empirical, semi-empirical and physical-based acoustic methods have been applied in different case studies, which provided relationships between scattering particles features derived from samples (i.e., concentration and grain size) and corresponding backscattering strength and sound attenuation. These methods entail different assumptions regarding sediment heterogeneity in the ensonified volume (e.g., particle size distribution (PSD) and spatial concentration gradient). Our work was to compare acoustic backscatter and attenuation properties of suspended sediments, sampled in the rivers Parana and Danube that represented rather different hydro-sedimentological conditions during the surveys. The Parana represents a large sandy river, characterized through a huge watershed and the typical bimodal PSD of sediment in suspension, while the Danube represents in the investigated reach an exposed sand-gravel bed and clay-silt particles transported in the water column in suspension. Sand and clay-silt concentrations clearly dominate the analyzed backscattering strength in the rivers Parana and Danube, respectively, with an effect of PSD level of sorting in the latter case. This comparison clarifies the extent of assumptions made, eventually advising on the actual possibility of applying certain ADCP methods, depending on the expected concentration gradients and PSD of suspended sediment to be investigated.

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The implications of laser‐diffraction measurements of sediment size distributions in a river to the potential use of acoustic backscatter for sediment measurements

Agrawal

Hanes

2015

Water Resources Research

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We construct vertical profiles of the acoustic attenuation and back‐scattering properties of a river column from measured particle concentration and size distribution profiles. The particle size and concentration data were collected in situ in the Cowlitz River in Washington, U.S., using a laser diffraction‐instrument LISST‐SL. The particle size distribution was bimodal, comprising a vertically well‐mixed washload, and a suspended load that was similar to Rouse profiles. We then explore how well the results of converting these synthetic profiles to recover an acoustic equivalent sediment concentration and acoustic equivalent size compare with laser data in this bimodal environment. The acoustic scattering and attenuation properties are computed for four distinct frequencies: 0.5, 1, 3, and 5 MHz. It is seen that at the lowest frequency, 500 KHz, the acoustic attenuation throughout the water column is nearly constant and determined primarily by particles of size smaller than ∼30 microns, i.e., the washload. At the next higher frequency, 1 MHz, the suspended load also contributed to attenuation, but even so, attenuation remained nearly constant over the vertical profile. Thus, at the two lower frequencies, attenuation was decoupled from scattering, making the inverse problem explicit for inversion. In contrast, at the two highest frequencies, scattering of sound by the suspended mode became the dominant contributor to attenuation, and attenuation varied by an order of magnitude over river depth. As for backscatter, the computed acoustic backscatter strength was determined by a combination of the washload and suspended sediment mode at all four frequencies. A fairly narrow monotonic relationship was found between total sediment concentration and locally computed backscatter, effectively providing a calibration between local backscatter signal strength and suspended sediment concentration. Such a relationship existed throughout the water column, for every frequency. The sediment concentration derived from backscatter at a pair of frequencies was within ∼50% of the value measured by laser diffraction; however, the acoustic equivalent diameter exceeded the laser volume mean diameter by up to an order of magnitude. The robustness of these results for application to other flow regimes or rivers remains to be investigated.

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Multi-frequency acoustics for suspended sediment studies: an application in the Parana River

Cited by 46 publications

References 28 publications

Optimizing Dredge-and-Dump Activities for River Navigability Using a Hydro-Morphodynamic Model

Optimizing Dredge-and-Dump Activities for River Navigability Using a Hydro-Morphodynamic Model

The Acoustic Properties of Suspended Sediment in Large Rivers: Consequences on ADCP Methods Applicability

The implications of laser‐diffraction measurements of sediment size distributions in a river to the potential use of acoustic backscatter for sediment measurements

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