22 results on '"Grangeon, Thomas"'
Search Results
2. Saturation-excess overland flow in the European loess belt: An underestimated process?
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Landemaine, Valentin, Cerdan, Olivier, Grangeon, Thomas, Vandromme, Rosalie, Laignel, Benoit, Evrard, Olivier, Salvador-Blanes, Sébastien, and Laceby, J. Patrick
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- 2023
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3. Hydrosedimentary behavior of a field combining surface drains and tile drains
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Gaillot, Arthur, Salvador-Blanes, Sébastien, Cerdan, Olivier, Vanhooydonck, Pierre, Grangeon, Thomas, Desmet, Marc, and Delbart, Célestine
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- 2023
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4. Dynamic parameterization of soil surface characteristics for hydrological models in agricultural catchments
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Grangeon, Thomas, Vandromme, Rosalie, Pak, Lai Ting, Martin, Philippe, Cerdan, Olivier, Richet, Jean-Baptiste, Evrard, Olivier, Souchère, Véronique, Auzet, Anne-Véronique, Ludwig, Bruno, and Ouvry, Jean-François
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- 2022
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5. Modelling effects of forest fire and post-fire management in a catchment prone to erosion: Impacts on sediment yield
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De Girolamo, Anna Maria, Cerdan, Olivier, Grangeon, Thomas, Ricci, Giovanni Francesco, Vandromme, Rosalie, and Lo Porto, Antonio
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- 2022
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6. What do models tell us about water and sediment connectivity?
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Baartman, Jantiene E.M., Nunes, João Pedro, Masselink, Rens, Darboux, Frédéric, Bielders, Charles, Degré, Aurore, Cantreul, Vincent, Cerdan, Olivier, Grangeon, Thomas, Fiener, Peter, Wilken, Florian, Schindewolf, Marcus, and Wainwright, John
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- 2020
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7. Lessons learnt on the impact of an unprecedented soil decontamination program in Fukushima on contaminant fluxes.
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Vandromme, Rosalie, Seiji Hayashi, Hideki Tsuji, Evrard, Olivier, Grangeon, Thomas, Landemaine, Valentin, Laceby, John Patrick, Yoshifumi Wakiyama, and Cerdan, Olivier
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SOIL remediation ,NUCLEAR power plant accidents ,NUCLEAR accidents ,NUCLEAR warfare ,NUCLEAR power plants ,PERMEATION tubes ,WATERSHEDS - Abstract
In the context of elevated concerns related to nuclear accidents and warfare, the lessons learnt from the Fukushima Daiichi Nuclear Power Plant accident in 2011 are important. In particular, Japanese authorities implemented an ambitious decontamination program to reduce the air dose rate in order to facilitate the return of the local inhabitants to previously evacuated areas. This approach contrasts the strategy adopted in Chernobyl, where the most contaminated areas remain off limits. Nonetheless, the effectiveness of the Japanese decontamination strategy on the dispersion of radioactive contaminant fluxes across mountainous landscapes exposed to typhoons has not been quantified. Based on the unique combination of river monitoring and modeling in a catchment representative of the most impacted area in Japan, we demonstrate that decontamination of 16% of the catchment area resulted in a decrease of 17% of sediment-bound radioactive fluxes in rivers. Decontamination operations were therefore relatively effective, although they could only be conducted in a small part of the area due to the dominance of steep forested slopes. In fact, 67% of the initial radiocesium contamination was calculated to remain stored in forested landscapes, which may contribute to future downstream radiocesium dispersion during erosive events. Given that only a limited proportion of the initial population had returned in 2019 (~30%), it raises the question as to whether decontaminating a small percentage of the contaminated area was worth the effort, the price, and the amount of waste generated? [ABSTRACT FROM AUTHOR]
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- 2023
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8. Dynamics of soil aggregate size in turbulent flow: Respective effect of soil type and suspended concentration
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Wendling, Valentin, Legout, Cédric, Gratiot, Nicolas, Michallet, Hervé, and Grangeon, Thomas
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- 2016
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9. Quantifying suspended sediment sources during runoff events in headwater catchments using spectrocolorimetry
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Legout, Cédric, Poulenard, Jérôme, Nemery, Julien, Navratil, Oldrich, Grangeon, Thomas, Evrard, Olivier, and Esteves, Michel
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- 2013
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10. Variability of the particle size of suspended sediment during highly concentrated flood events in a small mountainous catchment
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Grangeon, Thomas, Legout, Cédric, Esteves, Michel, Gratiot, Nicolas, and Navratil, Oldrich
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- 2012
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11. Spatial and temporal dynamics of soil erosion across different landscapes
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Cerdan, Olivier, Landemaine, Valentin, Foucher, Anthony, Evrard, Olivier, Grangeon, Thomas, Vandromme, Rosalie, Salvador-Blanes, Sebastien, Pak, Lai-Ting, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochimie Des Impacts (GEDI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Francois Rabelais [Tours], Association Régionale pour l'Etude et l'Amélioration des Sols (AREAS), Université de Tours (UT), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
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[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2018
12. Accroissement de la contribution des sources d'érosion aux rivières et plans d'eau (1950-2010) : le cas du Louroux (Indre-et-Loire, France)
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Foucher, Anthony, Le Gall, Marion, Salvador-Blanes, Sébastien, Evrard, Olivier, Cerdan, Olivier, Laceby, John-Patrick, Vandromme, Rosalie, Lefevre, Irène, Manière, Louis, Grangeon, Thomas, Bakyono, Jean-Paul, Desmet, Marc, GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours (UT), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochimie Des Impacts (GEDI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), AELB, Université de Tours, Centre de recherche sur l'Inflammation (CRI (UMR_S_1149 / ERL_8252 / U1149)), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Francois Rabelais [Tours], Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), and Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)
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[SDE.MCG]Environmental Sciences/Global Changes ,[SDE]Environmental Sciences ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,[SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment - Abstract
International audience; Soil erosion is recognized as one of the main processes triggering the physical and chemical degradation of water bodies. Although erosive dynamics have been widely described in morphogenic areas, much less is known about this process in lowland agricultural catchments.To address this issue, a multidisciplinary study was carried out at the scale of a small agricultural lowland catchment (Louroux catchment, France, 25 km (2)) to reconstruct the evolution of the soil erosion rates and sources, from the hillslopes to the deposition areas in the water bodies. This study's goal is specifically to understand the impact of changes in land use and agricultural practices after 1950 (field re-design, ditch creation, drainage) on sediment dynamics For this purpose, sediment cores were collected in a medieval pond (870AD) located at the outlet of the catchment. These cores have been dated and used to reconstruct the temporal variations in sediment fluxes over time (from 1954 to 2013). In addition, sediment sources were identified using fallout radionuclide measurements (cesium-137 and beryllium7 / excess lead-210 ratios). These results will contribute to the implementation of effective management measures to reduce the transfer of sediments from the hillslopes to the hydrosystems.; 14 15 L'érosion des sols est reconnue comme étant l'un des principaux processus à l'origine de la dégradation physico-16 chimique des masses d'eau. Les phénomènes érosifs, largement décrits en contexte morphogène, restent pourtant 17 peu étudiés en contexte de plaine. 18 Pour combler ce manque, une étude pluridisciplinaire a été menée à l'échelle d'un petit bassin versant (25 km²) 19 de plaine agricole drainée pour reconstruire l'évolution des taux et des sources d'érosion, depuis les zones 20 d'accumulation de matière jusqu'aux zones sources. Cette étude vise ainsi à comprendre l'impact des 21 aménagements intervenus dans le bassin après 1950 (remembrements, création de fossés, drainage) sur la 22 dynamique sédimentaire actuelle et passée. 23 À cette fin, des carottages ont été réalisés dans un étang médiéval (870AD) localisé à l'exutoire du bassin versant 24 du Louroux (France). Les carottes ont été datées et ont permis de reconstruire les variations temporelles du flux 25 sédimentaire (de 1954 à 2013), mais aussi de les associer avec les changements d'usage des sols. Par ailleurs, les 26 sources de sédiments ont été identifiées à partir de mesures de radionucléides (césium 137 et rapport béryllium 27 7/plomb 210 en excès). Ces résultats vont permettre de guider la mise en place d'aménagements pour lutter contre 28 le départ de matière sur les versants. 29 MOTS CLEFS : érosion, sédiment, colmatage, archive sédimentaire, traçage 30 31 Increase of erosion source contributions to rivers and lakes (1950-2010): 32 the case of the Louroux Pond (Central France) 33 Soil erosion is recognized as one of the main processes triggering the physical and chemical degradation of water 34 bodies. Although erosive dynamics have been widely described in morphogenic areas, much less is known about 35 this process in lowland agricultural catchments. 36 To address this issue, a multidisciplinary study was carried out at the scale of a small agricultural lowland 37 catchment (Louroux catchment, France, 25 km²) to reconstruct the evolution of the soil erosion rates and sources, 38 from the hillslopes to the deposition areas in the water bodies. This study's goal is specifically to understand the 39 impact of changes in land use and agricultural practices after 1950 (field redesign , ditch creation, drainage) on 40 sediment dynamics 41 For this purpose, sediment cores were collected in a medieval pond (870AD) located at the outlet of the 42 catchment. These cores have been dated and used to reconstruct the temporal variations in sediment fluxes over 43 time (from 1954 to 2013). In addition, sediment sources were identified using fallout radionuclide measurements 44 (cesium-137 and beryllium7 / excess lead-210 ratios). These results will contribute to the implementation of 45 effective management measures to reduce the transfer of sediments from the hillslopes to the hydrosystems. 46 KEY WORDS: erosion, sediment, siltation, lake deposits, sediment fingerprinting 47 48 49
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- 2017
13. A critical zone observatory dedicated to suspended sediment transport: The meso‐scale Galabre catchment (southern French Alps).
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Legout, Cédric, Freche, Guilhem, Biron, Romain, Esteves, Michel, Navratil, Oldrich, Nord, Guillaume, Uber, Magdalena, Grangeon, Thomas, Hachgenei, Nico, Boudevillain, Brice, Voiron, Céline, and Spadini, Lorenzo
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SUSPENDED sediments ,SEDIMENT transport ,OBSERVATORIES ,RAINDROP size ,METEOROLOGICAL stations ,WATERSHEDS ,ATMOSPHERIC turbidity ,TURBIDITY - Abstract
The 20 km2 Galabre catchment belongs to the French network of critical zone observatories (OZCAR; Gaillardet et al., Vadose Zone Journal, 2018, 17(1), 1–24). It is representative of the sedimentary lithology and meteorological forcing found in Mediterranean and mountainous areas. Due to the presence of highly erodible and sloping badlands on various lithologies, the site was instrumented in 2007 to understand the dynamics of suspended sediments (SS) in such areas. Two meteorological stations including measurements of air temperature, wind speed and direction, air moisture, rainfall intensity, raindrop size and velocity distribution were installed both in the upper and lower part of the catchment. At the catchment outlet, a gauging station records the water level, temperature and turbidity (10 min time‐step). Stream water samples are collected automatically to estimate SS concentration‐turbidity relationships, allowing quantification of SS fluxes with known uncertainty. The sediment samples are further characterized by measuring their particle size distributions and by applying a low‐cost sediment fingerprinting approach using spectrocolorimetric tracers. Thus, the contributions of badlands located on different lithologies to total SS flux are quantified at a high temporal resolution, providing the opportunity to better analyse the links between meteorological forcing variability and watershed hydrosedimentary response. The set of measurements was extended to the dissolved phase in 2017. Both stream water electrical conductivity and major ion concentrations are measured each week and every 3 h during storm events. This extension of measurements to the dissolved phase will allow progress in understanding both the origin of the water during the events and the partitioning between particulate and dissolved fluxes of solutes in the critical zone. All data sets are available at https://doi.osug.fr/public/DRAIXBLEONE_GAL/index.html. [ABSTRACT FROM AUTHOR]
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- 2021
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14. Impact of model simplifications on soil erosion predictions: application of the GLUE methodology to a distributed event-based model at the hillslope scale
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Cea, Luis, Legout, Cédric, Grangeon, Thomas, Nord, Guillaume, E.T.S. Ingenieros de Caminos Canales y Puertos, Universidade da Coruña, Laboratoire d'étude des transferts en hydrologie et environnement (LTHE), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Institut des Géosciences de l’Environnement (IGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Université de Tours (UT)
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[SDU]Sciences of the Universe [physics] - Abstract
International audience; In this paper, we analyse how the performance and calibration of a distributed event-based soil erosion model at the hillslopescale is affected by different simplifications on the parameterizations used to compute the production of suspended sediment byrainfall and runoff. Six modelling scenarios of different complexity are used to evaluate the temporal variability of thesedimentograph at the outlet of a 60 m long cultivated hillslope. The six scenarios are calibrated within the generalized likelihooduncertainty estimation framework in order to account for parameter uncertainty, and their performance is evaluated againstexperimental data registered during five storm events. The Nash–Sutcliffe efficiency, percent bias and coverage performanceratios show that the sedimentary response of the hillslope in terms of mass flux of eroded soil can be efficiently captured by amodel structure including only two soil erodibility parameters, which control the rainfall and runoff production of suspendedsediment. Increasing the number of parameters makes the calibration process more complex without increasing in a noticeablemanner the predictive capability of the model.
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- 2016
15. Les observatoires du ruissellement : comprendre les processus pour améliorer les modélisations.
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Grangeon, Thomas, Cerdan, Olivier, Landemaine, Valentin, Vandromme, Rosalie, Desprats, Jean-François, Salvador-Blanes, Sebastien, Vanhooydonck, Pierre, Gaillot, Arthur, Maniere, Louis, Pene-Galland, Isabelle, Evrard, Olivier, Foucher, Anthony, Ledieu, Lauriane, Simonneau, Anaëlle, Ouvry, Jean-François, and Pak, Lai Ting
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RUNOFF models ,SOIL classification ,SOIL moisture ,SURFACE states ,RUNOFF - Abstract
Copyright of Houille Blanche is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2020
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16. Quantifying hydro-sedimentary transfers in a lowland tile-drained agricultural catchment.
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Grangeon, Thomas, Ceriani, Valeria, Evrard, Olivier, Grison, Aurélie, Vandromme, Rosalie, Gaillot, Arthur, Cerdan, Olivier, and Salvador-Blanes, Sébastien
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SOIL macropores , *RAINFALL frequencies , *WATERLOGGING (Soils) , *WATER transfer , *SOIL erosion - Abstract
• Two contrasting years of monitoring of an agricultural tile-drained catchment. • Water and suspended particle transfers displayed high temporal variability. • Two transfer pathways to tile drains were observed. • Suspended particle dynamics in tile drains may be controlled by sediment storage and exhaustion. Soil erosion, runoff and sediment connectivity are strongly impacted by anthropogenic features in lowland agricultural catchments. Among these landscape features, the role played by tile drainage on water and sediment transfers and hillslope-to-river connectivity in drained catchments remains poorly understood. This study quantified water and sediment transfers in a tile drained catchment of central France by combining high frequency rainfall, discharge and sediment concentration measurements at the outlet of a set of 10 tile drained plots (34 ha) and at the medium-sized (120 km2) catchment scale. Over the monitoring period, including a dry and a wet year compared to average conditions (one year with 112% of the mean annual rainfall and one year with 64% of the mean annual rainfall), 36 rainfall-flood events were recorded and analyzed. The high frequency analysis of water and sediment transfers in tile-drained plots showed a high seasonal variability and the occurrence of two transfer pathways in the soil column including the slow drainage of saturated soils and the occurrence of preferential flow pathways through the soil column. Indeed, 13 of the 36 recorded flood events showed hydrographs with two components, reflecting these two pathways: slow transfers in the soil columns and fast transfers through soil macropores and/or cracks. Indeed, at the beginning of the flood event, a high-magnitude peak overlaid on the hydrograph. On average, this fast peak contributed 15% of the water and sediment fluxes. The sediment dynamics in tile drains was suggested to depend on sediment storage and exhaustion processes occurring in the tile drain network. [ABSTRACT FROM AUTHOR]
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- 2021
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17. The scale dependency of erosion and runoff for two agricultural catchments in the Western Paris Basin, France.
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Cerdan, Olivier, Landemaine, Valentin, Laignel, Benoit, Evrard, Olivier, Salavador-Blanes, Sébastien, Grangeon, Thomas, Vandromme, Rosalie, and Laceby, Patrick
- Published
- 2019
18. What do models tell us about water and sediment connectivity?
- Author
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Baartman, Jantiene E.M., Nunes, João Pedro, Masselink, Rens, Darboux, Frédéric, Bielders, Charles, Degré, Aurore, Cantreul, Vincent, Cerdan, Olivier, Grangeon, Thomas, Fiener, Peter, Wilken, Florian, Schindewolf, Marcus, and Wainwright, John
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Connectivity ,13. Climate action ,Erosion models ,Model comparison ,15. Life on land ,Catchment - Abstract
Connectivity has been embraced by the geosciences community as a useful concept to understand and describe hydrological functioning and sediment movement through catchments. Mathematical modelling has been used for decades to quantify and predict erosion and transport of sediments, e.g. in scenarios of land use change or conservation measures. Being intrigued by both models and the connectivity concept, as a group of modellers we aimed at investigating what different models could tell us about connectivity. Therefore, we evaluated the response of contrasted spatially-distributed models to landscape connectivity features and explained the differences based on different model structures. A total of 53 scenarios were built with varying field sizes and orientations, as well as the implementation of soil conservation measures. These scenarios were simulated, for two rainfall intensities, with five event- and process-based water and soil erosion models – EROSION3D, FullSWOF_2D, LandSoil, OpenLISEM and Watersed. Results showed that rainfall amount plays the most important role in determining relative export and connected area of runoff and sediment in all models, indicating that functional aspects of connectivity were more important than structural connectivity. As for the role of structural landscape elements, there was no overall agreement between models regarding the effects of field sizes, crop allocation pattern, and conservation practices; agreement was also low on the spatial patterns of connectivity. This overall disagreement between models was unexpected. The results of this exercise suggest that the correct parameterization of runoff and sediment production and of routing patterns may be an important issue. Thus, incorporating connectivity functions based on routing would help modelling forward. Our results also suggest that structural connectivity indices may not suffice to represent connectivity in this type of catchment (relatively simple and monotonous land cover), and functional connectivity indices should be applied., Geomorphology, 367, ISSN:0169-555x, ISSN:1872-695X
19. Des versants aux masses d'eau : érosion, colmatage et envasement.
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Vandromme, Rosalie, Evrard, Olivier, Grangeon, Thomas, Cerdan, Olivier, and Salvador-Blanes, Sébastien
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SOIL erosion ,AGRICULTURAL policy ,SILT ,EROSION ,COLLOIDS - Published
- 2017
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20. Analysis of seasonal variation in the hydrological behaviour of a field combining surface and tile drainage.
- Author
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Gaillot, Arthur, Delbart, Célestine, Salvador-Blanes, Sébastien, Vanhooydonck, Pierre, Desmet, Marc, Grangeon, Thomas, Noret, Aurélie, and Cerdan, Olivier
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RAINWATER , *SOIL moisture , *WATERLOGGING (Soils) , *DRAINAGE , *SOIL dynamics , *RAINFALL - Abstract
Agricultural drainage increases hydrological connectivity between fields and receiving environments. Tile drains and drainage ditches are the main drainage types studied at the field scale. They can be associated with temporary surface drains to improve the removal of surface water. Combining surface drains with tile drains is likely to modify surface runoff and soil water dynamics. The behaviour of tile-drained fields has been studied at the event scale, but few studies have been conducted over a full hydrological year, and no studies have quantified water volumes in a field combining surface and tile drainage. So quantifications of water partition between surface drainage, tile drainage and soil water are needed to understand the hydrological behaviour of a field combining surface and tile drains. Moreover, at the event scale, few studies showed macropores can contribute to tile drain runoff but the partition between preferential flow and matrix flow is still unclear. It needs to be study depending on several parameters as soil type, soil water content or agricultural practice for a better understanding. In this study, high temporal resolution quantification of surface runoff and tile drainage was conducted for two full hydrological years to study hydrological functioning of the field using the water balance for a drained field. Soil water pathways were studied under dry and saturated soil conditions, tracing water by measuring stable isotope (18O and 2H) concentrations in rainwater, soil water, and surface and tile runoff. Runoff quantification showed that surface drainage and tile drainage respectively transferred 44% and 20% of annual effective rainfall. However, water balance showed that, at the annual scale, 65% of infiltrating water was not captured by tile drains. At the event scale, water tracing showed a season variation in macropores contribution depending on soil hydric state. Under dry conditions, rainwater was directly transferred to tile drains, likely through macropores. On saturated soil, pre-event soil water content provided most of the water flowing out from the tile drain, but rainfall can contribute up to 25% of the water flowing out from the tile drains. Combining water balance and water trancing allowed to propose a conceptual model for surface and tile drainage hydrological functioning at the event scale. • High temporal resolution monitoring of surface and tile drain runoffs. • Two years water balance of a field combining surface and tile drains. • Around 65% of infiltrating water is not intercepted by tile drains. • Macropore contribution to tile drain flow depends on soil hydric state. [ABSTRACT FROM AUTHOR]
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- 2023
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21. Geochemical and mineralogical characterization of streams and wetlands downstream a former uranium mine (Rophin, France).
- Author
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Grangeon, Sylvain, Roux, Céline, Lerouge, Catherine, Chardon, Patrick, Beuzeval, Romain, Montavon, Gilles, Claret, Francis, and Grangeon, Thomas
- Subjects
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WETLAND soils , *RIVER sediments , *WETLANDS , *HUMUS , *URANIUM mining , *ORE deposits , *ORGANIC acids , *FULVIC acids - Abstract
The geochemical distribution of U and associated major and trace elements (As, Li, Pb, Sr, Zn) was studied at the former Rophin U mine (Puy-de-Dôme, France). Three zones of contrasting radiological settings were identified and sampled: a background area (<200 nSv·h−1), a streambed flowing downstream of the former mine (radiation level between 200 and 800 nSv·h−1) and a wetland soil (>1000 nSv·h−1). Sediment and water samples were collected both in a streambed located in the background area and in the streambed downslope the former mining area, and a soil sample was collected in the wetland downslope. Using both sequential and selective chemical extractions, and quantifying also the chemical reservoirs of As, Li, Pb, Sr, and Zn, it could be concluded that, in the streams, U was mainly bounded to primary ore minerals (phosphates) that were transported through particulate transport. It was also bound, to a lower extent, to clays, Mn oxyhydroxides and organic matter, certainly due to the sorption of aqueous U originating from partial dissolution or leaching of primary ore materials. Ore minerals remaining stable in the stream sediments were certainly included in a quartz matrix and hence were not in accessible for dissolution. In the wetland soil, selective extractions evidenced that U was about evenly distributed between humid/fulvic acids and organic matter unaffected by NH 4 OH 1M. [Display omitted] • Investigation of the radiological and geochemical settings downstream a former U mine. • In streams, U migration dictated by interplay between sorption of aqueous U and particulate transport. • In stream sediments, U primarily bound to ore material and to lesser extent clay, Fe/Mn hydroxides, and organic matter. • In a wetland soil, U bound to humic/fulvic acids and possibly lignin, clue for U uptake by plants. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. Improvement of a radiochemical separation for selenium 79: Applications to effluents and nuclear wastes
- Author
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Frechou, Carole, Aguerre, Sandrine, Degros, Jean-Pierre, Kerlau, Gilles, and Grangeon, Thomas
- Subjects
- *
HALF-life (Nuclear physics) , *NATIVE element minerals , *RADIOACTIVE decay , *RADIOACTIVE waste disposal - Abstract
Abstract: Selenium 79 is a beta emitter produced from 235U fission and is one of the long half-life radionuclides of interest in nuclear waste disposal problematic because of its potential migration capacity to the surface environment. Measurement of 79Se is particularly difficult due to its low activity in waste matrices (about 10−3 Bqg−1). A radiochemical procedure based on ion exchange separations was already described in a previous paper. This work presents different applications of the radiochemical separation to waste samples and an improvement of this procedure, including a selective extraction of selenium as diethylselenium in an organic solvent followed by a re-extraction in aqueous medium. This additional step allows the decontamination factor to be increased with the aim of counting 79Se by liquid scintillation counting. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
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