Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting - BRGM - Bureau de recherches géologiques et minières Accéder directement au contenu
Article Dans Une Revue Geomorphology Année : 2015

Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting

Résumé

Soil erosion is one of the main factors influencing land degradation and water quality at the global scale. Identifying the main sediment sources is therefore essential for the implementation of appropriate soil erosion mitigation measures. Accordingly, caesium-137 (137Cs) concentrations were used to determine the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137Cs concentrations are often dependent on particle size, specific surface area (SSA) and novel thorium (Th) based particle size corrections were applied. Surface and subsurface samples were collected to characterize the radionuclide properties of potential sources. Sediment samples were collected during one hydrological year and a sediment core was sampled to represent sediment accumulated over a longer temporal period. Additionally, sediment from tile drains was sampled to determine the radionuclide properties of sediment exported from the drainage network. A distribution modelling approach was used to quantify the relative sediment contributions from surface and subsurface sources. The results highlight a substantial enrichment in fine particles and associated 137Cs concentrations between the sources and the sediment. The application of both correction factors reduced this difference, with the Th correction providing a more accurate comparison of source and sediment samples than the SSA correction. Modelling results clearly indicate the dominance of surface sources during the flood events and in the sediment core. Sediment exported from the drainage network was modelled to originate predominantly from surface sources. This study demonstrates the potential of Th to correct for 137Cs particle size enrichment. More importantly, this research indicates that drainage networks may significantly increase the connectivity of surface sources to stream networks. Managing sediment transferred through drainage networks may reduce the deleterious effects of suspended sediment loads on riverine systems in similar lowland drained agricultural catchments.
Fichier principal
Vignette du fichier
Foucher_Geomor_2015_post-print.pdf (2.53 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01400992 , version 1 (26-05-2020)

Identifiants

Citer

Anthony Foucher, Patrick J. Laceby, Sébastien Salvador-Blanes, O. Evrard, Marion Le Gall, et al.. Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting. Geomorphology, 2015, 250, pp.271 - 281. ⟨10.1016/j.geomorph.2015.09.007⟩. ⟨hal-01400992⟩
376 Consultations
240 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More