Measuring bedload in gravel-bed mountain rivers: averaging methods and sampling strategies | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Measuring bedload in gravel-bed mountain rivers: averaging methods and sampling strategies

Type de publication:

Journal Article

Source:

Geodinamica Acta, Volume 21, Ticket 1-2, p.81-92 (2008)

ISBN:

0985-3111

Numéro d'accès:

WOS:000256527400008

Mots-clés:

Dynamique des Fluides Géologiques ; N° Contribution : 2259, UMR 7154

Résumé:

<p>A dataset of more than 1,000 individual bedload samples coupled with hydraulic flow variables (water depth and velocity) was collected on two high mountain rivers the torrent de Saint Pierre, a proglacial gravel-bed river in the French Alps, in July 2002 and the Urumqi River, in the Chinese Tianshan Mountains during summer 2005 and 2006. Analysis of the dataset leads to question the usual section averaged sampling procedure of bedload using Helley-Smith type bedload sampler. It is shown that this procedure is inadequate to catch the full range of flow conditions. Comparison between moving averages on individual datasets and section averages furthermore show that this technique can lead to significantly different rating curves with predictions differing by more than an order of magnitude. Single point sampling is shown to be much more adequate than multiple point sampling and section averaging provided the dataset is sufficiently large. (C) 2008 Lavoisier SAS. All rights reserved.</p>