Movement of cobbles in a gravel-bed stream during a flood season

Butler, Paul Ray

doi:10.1130/0016-7606(1977)88<1072:mociag>2.0.co;2

Cited by 20 publications

(5 citation statements)

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“…Both active and passive tracers have played an important role in the research on bedload transport (Bravard and Petit, 2000). A number of studies have focused on the relationship between the distance and the size of the transported elements (Helley, 1969;Butler, 1977;Ergenzinger et al, 1989;Church and Hassan, 1992;Hassan et al, 1999;Pyrce and Ashmore, 2003;MacNamara and Borden, 2004). Other studies have examined the limits to bedload mobilization (Petit, 1987;Schmidt and Ergenzinger, 1992;Barta et al, 1994;Wilcock et al, 1996;Wilcock, 1997;Ferguson, 2005;Petit et al, 2005a).…”

Section: Introductionmentioning

confidence: 99%

Comparison of methods for quantifying active layer dynamics and bedload discharge in armoured gravel‐bed rivers

Houbrechts

Campenhout

Levecq

et al. 2012

Earth Surf Processes Landf

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Several methods were employed in the Ardennian rivers (Belgium) to determine the depth of the active layer mobilized during floods and to evaluate the bedload discharge associated with these events. The use of scour chains has shown that the depth of the active layer is systematically less than the b‐axis of the average particle size (D50) of the elements which compose the surface layer of the riffles. This indicates that only a partial transport exists during low magnitude floods. The bedload discharge has been evaluated by combining data obtained using the scour chains technique and the distance covered by tracers. Quantities of sediment transported during frequent floods are relatively low (0·02 t km–2) due to the armour layer which protects the subsurface material. These low values are also related to the fact that the distance calculated for mobilized bedload only applies to tracers fitted with PIT (passive integrated transponder)‐tags (diameter > 20 mm), whereas part of the bedload discharge is composed of sand and fine gravel transported over greater distances than the pebbles. The break‐up of the armour layer was observed only once, for a decennial discharge. During this event, the bedload discharge increased considerably (2 t km–2). The use of sediment traps, data from dredging and a Helley–Smith sampler confirm the low bedload transport in Ardennian rivers in comparison to the bedload transport in other geomorphological contexts. This difference is explained by the presence of an armoured layer but also by the imbricated structures of flat bed elements which increase the resistance to the flow. Finally, the use of the old iron industry wastes allowed to quantify the thickness of the bed reworked over the past centuries. In the Lembrée River, the river‐bed contains slag elements up to a depth of about 50 cm, indicating that exceptional floods may rework the bed to a considerable depth. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Comparison of methods for quantifying active layer dynamics and bedload discharge in armoured gravel‐bed rivers

Houbrechts

Campenhout

Levecq

et al. 2012

Earth Surf Processes Landf

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“…Several particle tracing and tracking techniques have been developed to study numerous aspects of bedload movement and particle motion in gravel-bed streams (see review by Sear et al (2000)). Most involve techniques of varying degrees of sophistication to locate tagged particles after significant flow events such as visually locating painted rocks (Ferguson and Wathen, 1998), finding magnetically tagged rocks with a metal detector (Butler, 1977;Schmidt and Ergenzinger, 1992;Ferguson and Wathen, 1998), and finding rocks implanted with radio transmitters (Chacho et al, 1989;Schmidt and Ergenzinger, 1992). These post-event techniques provide valuable information on properties such as particle travel distances (Hassan et al, 1992), spatial distribution of entrainment (Wilcock, 1997) and vertical mixing (Hassan et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Observations on the movement of coarse gravel using implanted motion‐sensing radio transmitters

McNamara

Borden

2004

Hydrological Processes

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Abstract:Motion-sensing radio transmitters were implanted in cobbles (72-92 mm diameter) and placed in a stream in southwest Idaho for 43 days during a snowmelt period. The radios transmit different pulse rates depending on whether the rocks are at rest or in motion. Every 30 s, a datalogger samples the receiver and records the pulse rate of the transmitters. Such information can be used to assess numerous properties of particle transport that are beyond the capabilities of conventional tracking methods. Conclusions include: (i) rocks are more likely to move on rising hydrograph limbs than on falling hydrograph limbs; (ii) the average Shields' parameter is 0Ð046; (iii) rocks move only a fraction of the time between initial and final motion during an event; (iv) the distributions of motion and rest periods are best modeled by gamma functions rather than exponential, but the distributions approach exponential as the tails are trimmed.

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“…Recovery rates range from 5 to 50%. Even enhancing the chance of rediscovery by use of metal-tagged clasts and a metal detector (Butler, 1977) gives a recovery of only 35%. This places limitations on the ability to make firm statements about the range of transport distances (Frostick & Reid, 1982) though individually numbered particles can indicate their particular transport vectors at least on a flood by flood basis.…”

Section: Introductionmentioning

confidence: 99%

An electromagnetic device for automatic detection of bedload motion and its field applications

1984

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A new sensor for the continuous and unmanned detection and recording of bedload motion is described. The sensor acts in the same fashion as a conventional metal detector but is elongate and installed permanently in the bed of an alluvial channel. Artificial clasts are labelled with short lengths of ferrite rod and are seeded upstream from the sensor, replacing bed particles. The entrainment of seeded clasts takes them over the sensor where they distort the magnetic field and produce a change in inductance that is detected and recorded. A field installation demonstrates the value of the sensor by revealing for the first time in coarse‐grained alluvium the spasmodic nature of particle motion reminiscent of kinematic waves. It also illustrates the importance of pebble clusters in delaying particle entrainment.

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Movement of cobbles in a gravel-bed stream during a flood season

Cited by 20 publications

References 0 publications

Comparison of methods for quantifying active layer dynamics and bedload discharge in armoured gravel‐bed rivers

Comparison of methods for quantifying active layer dynamics and bedload discharge in armoured gravel‐bed rivers

Observations on the movement of coarse gravel using implanted motion‐sensing radio transmitters

An electromagnetic device for automatic detection of bedload motion and its field applications

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