Characteristics and use of Helley-Smith type bedload samplers

Hubbell, D.W.; Stevens, Herbert H.; Skinner, J.V.; Beverage, Joseph P.

doi:10.3133/ofr86415w

Cited by 6 publications

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“…These measurements were continued till sunset and in some occasions after sunset. The duration of sampling depended on the bed load discharge to ensure that only 30% of the basket was filled (Hubbell et al 1986). In principle, the Helley-Smith sampler was employed in the manner prescribed by Emmett (1980).…”

Section: Bed Load Data-measurementmentioning

confidence: 99%

Studying of flow model and bed load transport in a coarse bed river: case study – Aland River, Iran

Roushangar

Hassanzadeh

Keynejad

et al. 2010

Journal of Hydroinformatics

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This paper describes a mathematical model which solves the 1D unsteady flow over a mobile bed.The model is based on the Richtmyer second-order explicit scheme. Comparison of the model results with the experimental flume data for alluvial steady flow (aggradation due to overloading) and unsteady flow shows that, by using the two-step method of Richtmyer, one can solve the equations, governing the phenomenon, in a coupled method with the desired accuracy. Firstly, the Badalan reach located at the Aland River is considered. Variations of flow rate, water level and bed level profiles due to flood hydrographs are assessed. Secondly, bed load discharge data were collected from the Aland River and a variety of bed load discharge formulae were compared with measured data. Results show that, by using the grain size of the bed surface layer to predict the bed load discharge, a larger relative error will occur compared to the other two cases and a proper choice of grain size has the main role in reduction of the relative error of bed load discharge estimation in gravel bed rivers. The applicability of formulae varies depending on flow rate, and should be split into low and high flow transport formulae.

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Section: Bed Load Data-measurementmentioning

confidence: 99%

Studying of flow model and bed load transport in a coarse bed river: case study – Aland River, Iran

Roushangar

Hassanzadeh

Keynejad

et al. 2010

Journal of Hydroinformatics

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Total load transport in gravel bed and sand bed rivers case study: Chelichay watershed

Haddadchi

Omid

Sdehghani³

2013

International Journal of Sediment Research

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Bedload transport of fine gravel observed by motion-picture photography

et al. 1988

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Motion pictures taken at Duck Creek, a clear stream 6.5 m wide and 35 cm deep near Pinedale, Wyoming, provide detailed, quantitative information on both the modes of motion of individual bedload particles and the collective motions of large numbers of them. Bed shear stress was approximately 6 Pa (60 dynes cm−2), which was about twice the threshold for movement of the 4 mm median diameter fine gravel bed material; and transport was almost entirely as bedload. The displacements of individual particles occurred mainly by rolling of the majority of the particles and saltation of the smallest ones, and rarely by brief sliding of large, angular ones. Entrainment was principally by rollover of the larger particles and liftoff of the smaller ones, and infrequently by ejection caused by impacts, whereas distrainment was primarily by diminution of fluid forces in the case of rolling particles and by collisions with larger bed particles in the case of saltating ones. The displacement times averaged about 0.2−0.4 s and generally were much shorter than the intervening repose times. The collective motions of the particles were characterized by frequent, brief, localized, random sweep-transport events of very high rates of entrainment and transport, which in the aggregate transported approximately 70% of the total load moved. These events occurred 9% of the time at any particular point of the bed, lasted 1–2 s, affected areas typically 20–50 cm long by 10–20 cm wide, and involved bedload concentrations approximately 10 times greater than background. The distances travelled during displacements averaged about 15 times the particle diameter. Despite the differences in their dominant modes of movement, the 8–16 mm particles typically travelled only about 30% slower during displacement than the 2–4 mm ones, whose speeds averaged 21 cm s−1. Particles starting from the same point not only moved intermittently downstream but also dispersed both longitudinally and transversely, with diffusivities of 4.6 and 0.26 cm2 s−1, respectively. The bedload transport rates measured from the films were consistent with those determined conventionally with a bedload sampler. The 2–4 mm particles were entrained 6 times faster on finer areas of the bed, where 8–16 mm particles covered 6% of the surface area, than on coarser ones, where they covered 12%, even though 2–4 and 4–8 mm particles covered practically the same percentage areas in both cases. The 4–8 and 8–16 mm particles, in contrast, were entrained at the same rates in both cases. To within the statistical uncertainty, the rates of distrainment balanced the rates of entrainment for all three sizes, and were approximately proportional to the corresponding concentrations of bedload.

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Characteristics and use of Helley-Smith type bedload samplers

Cited by 6 publications

References 0 publications

Studying of flow model and bed load transport in a coarse bed river: case study – Aland River, Iran

Studying of flow model and bed load transport in a coarse bed river: case study – Aland River, Iran

Total load transport in gravel bed and sand bed rivers case study: Chelichay watershed

Bedload transport of fine gravel observed by motion-picture photography

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