Plume Measurement System (PLUMES) Calibration Experiment

Lohrmann, Atle; Huhta, C.

doi:10.21236/ada284594

Cited by 8 publications

(7 citation statements)

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“…Indeed, this has been used successfully in previous studies (e.g. Lohrmann and Huhta, 1994). However, no attempt is made to do so here because (i) the same type and size of bed material was used throughout the experiments and (ii) no comparison with data derived in other studies is made.…”

Section: Methodsmentioning

confidence: 99%

Suspended sediment concentration and the ripple–dune transition

Schindler

Robert

2004

Hydrological Processes

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Abstract:Flume experiments were conducted in order to monitor changes in flow turbulence intensity and suspended sediment concentration at seven stages across the ripple-dune transition and at three different positions above the bed surface. Three-dimensional velocity measurements were obtained using an acoustic Doppler velocimeter (ADV). Suspended sediment concentration (SSC) was monitored indirectly using ADV signal amplitude. Although limited to timeaveraged parameters, the analysis reveals that SSC varies significantly with stage across the transition and with sampling height. The statistical analysis also reveals an apparent uniformity of suspended sediment concentration with height above the bed in the lower half of the flow depth at the critical stage in the transition from ripples to dunes. This is also the stage at which turbulence intensity is maximized. Statistically significant correlations were also observed between suspended sediment concentrations and root-mean-square values of vertical velocity fluctuations. These correlations reflect the various levels of shear-layer activity and the distinct turbulent flow regions across the transition. Conversely, time-averaged values of Reynolds shear stress exhibit a very weak relationship with suspended sediment concentrations.

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Section: Methodsmentioning

confidence: 99%

Suspended sediment concentration and the ripple–dune transition

Schindler

Robert

2004

Hydrological Processes

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“…Thevenot et al [1992] developed calibration parameters as part of a study to monitor dredged material near Tylers Beach, Virginia, using Broadband‐ADCPs (BB‐ADCPs). Thevenot and Kraus [1993] compared optical and acoustic methods using a 2.4‐MHz BB‐ADCP in the Chesapeake Estuary and Lohrman and Huhta [1994] undertook a sediment calibration experiment in the laboratory to determine the fate of suspended sediments during dredging operations. Jay et al [1999] incorporated a correction function for improved calculation of beam spreading losses in the ADCP transducer near field to account for the complex acoustic beam pattern, and Holdaway et al [1999] accounted for sediment attenuation in their evaluation of ADCPs to estimate SSC.…”

Section: Technological Advances In Suspended Sediment Surrogate Monitmentioning

confidence: 99%

Technological advances in suspended‐sediment surrogate monitoring

Gray

Gartner

2009

Water Resources Research

160

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[1] Surrogate technologies to continuously monitor suspended sediment show promise toward supplanting traditional data collection methods requiring routine collection and analysis of water samples. Commercially available instruments operating on bulk optic (turbidity), laser optic, pressure difference, and acoustic backscatter principles are evaluated based on cost, reliability, robustness, accuracy, sample volume, susceptibility to biological fouling, and suitable range of mass concentration and particle size distribution. In situ turbidimeters are widely used. They provide reliable data where the point measurements can be reliably correlated to the river's mean cross section concentration value, effects of biological fouling can be minimized, and concentrations remain below the sensor's upper measurement limit. In situ laser diffraction instruments have similar limitations and can cost 6 times the approximate $5000 purchase price of a turbidimeter. However, laser diffraction instruments provide volumetric-concentration data in 32 size classes. Pressure differential instruments measure mass density in a water column, thus integrating substantially more streamflow than a point measurement. They are designed for monitoring medium-to-large concentrations, are generally unaffected by biological fouling, and cost about the same as a turbidimeter. However, their performance has been marginal in field applications. Acoustic Doppler profilers use acoustic backscatter to measure suspended sediment concentrations in orders of magnitude more streamflow than do instruments that rely on point measurements. The technology is relatively robust and generally immune to effects of biological fouling. Cost of a single-frequency device is about double that of a turbidimeter. Multifrequency arrays also provide the potential to resolve concentrations by clay silt versus sand size fractions. Multifrequency hydroacoustics shows the most promise for revolutionizing collection of continuous suspended sediment data by instruments that require only periodic calibration for correlation to mean concentrations in river cross sections. Broad application of proven suspended sediment surrogate technologies has the potential to revolutionize fluvial sediment monitoring. Once applied, benefits could be enormous, providing for safer, more frequent and consistent, arguably more accurate, and ultimately less expensive sediment data for managing the world's sedimentary resources.

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“…The PLUMES consists of equipment systems, including a broadband acoustic Doppler current profiler (BBADCP), and plume tracking techniques. Kraus and Thevenot (1992); Tubman (1994a and1994b), Kraus (1991); Thevenot, Prickett, and Kraus (1992); Lohrmann and Huhta (1994);and Tubman (1995) describe PLUMES development and testing. The system was tested in shallow-water placement sites in Mobile, AL (Kraus 1991), and Tylers Beach, VA (Thevenot, Prickett, and Kraus 1992).…”

Section: -65mentioning

confidence: 99%