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Downstream fining processes in sandy lowland rivers / Roy M. Frings in Journal of hydraulic research, Vol. 49 N° 2 (Mars/Avril 2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 N° 2 (Mars/Avril 2011) . - pp. 178-193 Titre : Downstream fining processes in sandy lowland rivers Type de document : texte imprimé Auteurs : Roy M. Frings, Auteur ; Willem Ottevanger, Auteur ; Kees (C.J.) Sloff, Auteur Année de publication : 2011 Article en page(s) : pp. 178-193 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Downstream  fining  Dune  sorting  Longitudinal  bed  profile  Meander  migration  Overbank  deposition  River  bifurcation  Sand-bed  river  Selective  transport  Rhine  River Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Downstream fining of river bed sediments is well known for gravel-bed rivers, but also occurs in sand-bed rivers. The objective of this study was to determine the effect of selective transport processes, dune sorting, overbank deposition, channel migration and river bifurcations on downstream fining in sandy lowland rivers subject to relative sea level rise, tidal water level variations and increasing river width. A numerical simulation model was built using the Delft3D software. Selective suspended-load transport appeared to be dominant over selective bed-load transport. Dune sorting and channel migration increase fining rates, but overbank deposition has an opposite effect. River bifurcations affect the fining rate because of their effect on the sediment supply to bifurcating lowland rivers. Downstream fining was found to develop within decades, but it took few centuries before the longitudinal bed profile and the fining rate attained dynamic equilibrium. A comparison of the modelled fining rates with those observed in the Rhine River shows reasonable agreement. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.561000 [article] Downstream fining processes in sandy lowland rivers [texte imprimé] / Roy M. Frings, Auteur ; Willem Ottevanger, Auteur ; Kees (C.J.) Sloff, Auteur . - 2011 . - pp. 178-193. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 N° 2 (Mars/Avril 2011) . - pp. 178-193 Mots-clés : Downstream  fining  Dune  sorting  Longitudinal  bed  profile  Meander  migration  Overbank  deposition  River  bifurcation  Sand-bed  river  Selective  transport  Rhine  River Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : Downstream fining of river bed sediments is well known for gravel-bed rivers, but also occurs in sand-bed rivers. The objective of this study was to determine the effect of selective transport processes, dune sorting, overbank deposition, channel migration and river bifurcations on downstream fining in sandy lowland rivers subject to relative sea level rise, tidal water level variations and increasing river width. A numerical simulation model was built using the Delft3D software. Selective suspended-load transport appeared to be dominant over selective bed-load transport. Dune sorting and channel migration increase fining rates, but overbank deposition has an opposite effect. River bifurcations affect the fining rate because of their effect on the sediment supply to bifurcating lowland rivers. Downstream fining was found to develop within decades, but it took few centuries before the longitudinal bed profile and the fining rate attained dynamic equilibrium. A comparison of the modelled fining rates with those observed in the Rhine River shows reasonable agreement. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.561000