Fréquence et importance du charriage dans les rivières du Massif ardennais

Houbrechts, Geoffrey; Hallot, Éric; Gob, Frédéric; Mols, Julien; Defechereux, Olivier; Petit, François

doi:10.7202/017998ar

Cited by 7 publications

(18 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Indeed, the bed material seems disproportionately small in relation to the competence of the river, which is capable of transporting considerable quantities of sediment. The mobilizing discharge is attained for a low recurrence interval (0·2 years) and bedload transport occurs for on average 15·5 days per year (Houbrechts et al ., ). Due to the frequency of mobilizing floods, this site allowed two complementary techniques to be tested: scour chains associated with PIT‐tag tracers, on the one hand, and bedload sampling using a Helley–Smith sampler, on the other hand.…”

Section: Study Sitesmentioning

confidence: 92%

“…During this period, various discharges occurred, ranging from 0·5 times the bankfull discharge (where bedload mobilization occurs) to the 10 year flood and sometimes even greater. Since this period, additional dredging campaigns were undertaken, providing values for almost 20 different rivers (Houbrechts et al ., ).…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, bedload samplers such as the Helley–Smith sampler (Helley and Smith, ) may be used. However, this requires taking measurements in awkward settings (the sampler should be used from a bridge), while the conditions suitable are relatively rare, as mobilizing discharges are not frequent (Andrews, ; Gintz et al ., ; Ryan and Porth, ; Houbrechts et al ., ). Furthermore, there are limits to the size of the transported material that may be sampled, depending on the dimensions of the opening nozzle of the sampler (Habersack et al ., ; Bunte et al ., ; Vericat et al ., ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Study Sitesmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…In these rivers, bedload transport occurs approximately 3 to 4 times per year and the critical discharge is exceeded on average from 5 to 20 days per year in relation to the size of the river (Houbrechts et al, 2006). Within the Ardenne Region, there are marked differences between the northern part and the southern part of the region.…”

Section: Description Of the Study Sitesmentioning

confidence: 96%

“…The river's bed is essentially composed of schist pebbles and rolled gravel from the highest terraces of the Meuse. Indeed, the bed material seems disproportionately small in relation to the competence of the river and thus the gravel entrainment threshold is attained for a low recurrence interval (0.2 years) and bedload transport occurs 15.5 days per year on average (Houbrechts et al, 2006). The second river studied outside the Ardenne Region is the Bocq River (site 6, Fig.…”

Section: Description Of the Study Sitesmentioning

confidence: 99%