9 results on '"Vautier, Franck"'
Search Results
2. Origin and Holocene geomorphological evolution of the landslide-dammed basin of la Narse de la Sauvetat (Massif Central, France)
- Author
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Mayoral, Alfredo, Peiry, Jean-Luc, Berger, Jean-François, Simon, François-Xavier, Vautier, Franck, and Miras, Yannick
- Published
- 2018
- Full Text
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3. A multi-scale approach of fluvial biogeomorphic dynamics using photogrammetry
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Hortobágyi, Borbála, Corenblit, Dov, Vautier, Franck, Steiger, Johannes, Roussel, Erwan, Burkart, Andreas, and Peiry, Jean-Luc
- Published
- 2017
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4. Removal of Riprap within Channelized Rivers: A Solution for the Restoration of Lateral Channel Dynamics and Bedload Replenishment?
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Arfeuillère, Anaïs, Steiger, Johannes, Gautier, Emmanuèle, Petit, Stéphane, Roussel, Erwan, Vautier, Franck, Voldoire, Olivier, and Saillard, Julien
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BED load ,STREAM restoration ,ALLUVIAL streams ,FLOODPLAINS ,RIPARIAN plants ,EROSION ,RIPARIAN areas - Abstract
Riverbank erosion is an essential morphodynamic process for the improvement of river health and the ecohydrogeomorphological functioning of alluvial rivers. Lateral channel dynamics and sediment supply caused by bank erosion largely create and maintain heterogeneous in-channel habitats for fauna and aquatic or riparian plant species. However, humans very early started to stabilize riverbanks in order to favour navigation or to prevent valuable land and infrastructures close to the channel from eroding. During the 20th century, bank protection works such as riprap considerably increased and blocked lateral channel erosion, causing a loss of local sediment supply, which in turn resulted in a decrease in local bedload transport and channel incision. The aim of the article is to evaluate to what extent riprap removal may be an efficient restoration measure in terms of the reactivation of bank erosion and the replenishment of the local bedload in gravel-bed floodplain rivers with a sufficient amount of freedom space. An experimental in situ restoration approach was chosen. First, riprap was removed at two geomorphologically contrasting sites on the Allier River, France. Second, bank retreat was monitored, and the volumes eroded were quantified using photogrammetric and LiDAR surveys. Third, in the case of post-restoration bank erosion, grain size and morphological channel evolution analyses were carried out. Our results suggested that the removal of riprap is an effective measure for certain but not all channelized floodplain reaches. The geomorphological and sedimentary contexts are two criteria that should be considered when selecting sites for restoration. Thus, this study helps river managers to better target the criteria to be taken into account for the selection of sites with high potential for the restoration of lateral channel dynamics. [ABSTRACT FROM AUTHOR]
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- 2023
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5. The Highest Gradient Model: A New Method for Analytical Assessment of the Efficiency of LiDAR-Derived Visualization Techniques for Landform Detection and Mapping
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Mayoral Pascual, Alfredo, Toumazet, Jean-Pierre, François-Xavier, Simon, Vautier, Franck, Peiry, Jean-Luc, Laboratoire de Géographie Physique et Environnementale (GEOLAB), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Clermont Auvergne (UCA)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Maison des Sciences de l'Homme de Clermont-Ferrand (MSH Clermont), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), UMI 3189 ESS Environnement, santé, sociétés, (UMI 3189), Centre National de la Recherche Scientifique (CNRS), Région Auvergne, AAP structurants en SHS 2013 : AYPONA, pAYsages et visages d’une agglomération arverne : apProche intégréeet diachrONique de l’occupAtion de l’Oppidum de coreNt (Auvergne, France), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)
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LiDAR ,[SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory ,highest gradient model ,[SHS.ENVIR]Humanities and Social Sciences/Environmental studies ,landforms detection ,Science ,microtopography ,[SDE.ES]Environmental Sciences/Environmental and Society ,visualization techniques ,spatial statistics - Abstract
International audience; ALS-derived raster visualization techniques have become common in recent years, opening up new possibilities for subtle landform detection in earth sciences and archaeology, but they have also introduced confusion for users. As a consequence, the choice between these visualization techniques is still mostly supported by empirical knowledge. Some attempts have been made to compare these techniques, but there is still a lack of analytical data. This work proposes a new method, based on gradient modelling and spatial statistics, to analytically assess the efficacy of these visualization techniques. A selected panel of outstanding visualization techniques was assessed first by a classic non-analytical approach, and secondly by the proposed new analytical approach. The comparison of results showed that the latter provided more detailed and objective data, not always consistent with previous empirical knowledge. These data allowed us to characterize with precision the terrain for which each visualization technique performs best. A combination ofvisualization techniques based on DEM manipulation (Slope and Local Relief Model) appeared to be the best choice for normal terrain morphometry, occasionally supported by illumination techniques such as Sky-View Factor or Negative Openness as a function of terrain characteristics.
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- 2017
6. Use of photogrammetry for the study of riparian vegetation dynamics
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Hortobágyi, Borbála, Vautier, Franck, Burkart, Andreas, Wrobel, Thomas Jan, Peiry, Jean-Luc, Steiger, Johannes, Corenblit, Dov Jean-François, Laboratoire de Géographie Physique et Environnementale (GEOLAB), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Clermont Auvergne (UCA)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Maison des Sciences de l'Homme de Clermont-Ferrand (MSH Clermont), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Institute für Bio- und Geowissenschaften, Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Institute of Plant Biochemistry, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Hortobágyi, Borbála, Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), and Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)
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[SDE] Environmental Sciences ,[SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,vegetation height model ,aerial photographs ,[SHS.GEO] Humanities and Social Sciences/Geography ,UAV ,[SDE]Environmental Sciences ,riparian vegetation ,[SHS] Humanities and Social Sciences ,[SHS.GEO]Humanities and Social Sciences/Geography ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,photogrammetry ,[SHS]Humanities and Social Sciences - Abstract
This study presents the results of methodological tests in aerial photogrammetry with the objective of a diachronic survey of riparian vegetation in three dimensions, i.e. its spatial distribution and height. The study is undertaken at two complementary scales. The first one corresponds to a 10 km reach of the Allier river floodplain. At this scale, aerial photographs were taken from a small airplane. The second level of analysis corresponds to a wooded point bar located within the 10 km reach. At this scale, the photographs were taken from an unmanned aerial vehicle (UAV). Canopy height models (CHM) are produced at two scales of analysis. The accuracy of the CHMs is then analysed by comparison with vegetation height measurements collected during a filed campaign. The results show significant agreement for the models derived from two approaches, with an error of one meter at the floodplain scale and few centimetres at the bar scale. This variation in error is mainly due to different photographic resolutions. The two approaches appeared to be complementary. The first one is adequate for mapping vegetation structure at the floodplain scale, the second for mapping vegetation in smaller areas but at a higher resolution., Cette étude présente les résultats de tests méthodologiques réalisés en photogrammétrie aérienne avec pour objectif le suivi diachronique de la végétation riveraine dans ses trois dimensions, c’est-à-dire sa distribution spatiale et sa hauteur. L’étude est menée à deux échelles d’analyse. La première échelle est celle d’un tronçon longitudinal de 10 km de la plaine alluviale de la rivière Allier. À cette échelle de travail, un avion a été utilisé pour les prises de vue aérienne. La deuxième échelle d’analyse est celle d’un banc boisé, localisé dans la zone de 10 km. À cette échelle, la couverture photographique a été faite à l’aide d’un drone. Pour les deux objets d’étude des modèles de hauteur du couvert végétal (MHC) sont produits. La précision des MHC est ensuite vérifiée à partir de la mesure de la hauteur d’arbres sur le terrain. Les résultats révèlent une très bonne précision des modèles pour les deux approches, de l’ordre du mètre à l’échelle du tronçon de 10 km et de quelques centimètres à l’échelle du banc. Cette inégalité s’explique surtout par des résolutions photographiques différentes pour les deux missions. Il ressort de ce travail que les deux approches sont complémentaires. La première permet de cartographier la structure de la végétation à l’échelle de la plaine alluviale, la deuxième permet une cartographie de la végétation à plus haute résolution mais seulement à une échelle plus réduite.
- Published
- 2015
7. The biogeomorphological life cycle of poplars during the fluvial biogeomorphological succession: a special focus on Populus nigra L
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Corenblit, Dov, Steiger, Johannes, González, Eduardo, Gurnell, Angela M., Charrier, Gaspard, Darrozes, José, Dousseau, Julien, Julien, Frédéric, Lambs, Luc, Larrue, Sébastien, Roussel, Erwan, Vautier, Franck, Voldoire, Olivier, Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Blaise Pascal - UBP (FRANCE), Ecole nationale supérieure d'architecture de Clermont Ferrand - ENSACF (FRANCE), Maison des Sciences de l’Homme - MSH (FRANCE), Queen Mary University of London - QMUL (UNITED KINGDOM), Université Laval (CANADA), Géosciences Environnement Toulouse - GET (Toulouse, France), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
- Subjects
Biogeomorphological life cycle ,Evolutionary geomorphology ,Ecosystèmes ,Abiotic-biotic feedback ,Salicaceae ,Biodiversité et Ecologie ,Biogeomorphology ,Fluvial biogeomorphic succession model ,Engineer species - Abstract
Riverine ecosystems are recurrently rejuvenated during destructive flood events and vegetation succession starts again. Poplars (i.e. species from Populus genera) respond to hydrogeomorphological constraints, but, in turn, also influence these processes. Thus, poplar development on bare mineral substrates is not exclusively a one-way vegetative process. Reciprocal interactions and adjustments between poplar species and sediment dynamics during their life cycle lead to the emergence of biogeomorphological entities within the fluvial corridor, such as vegetated islands, benches and floodplains. Based on a review of geomorphological, biological and ecological literature, we have identified and described the co-constructing processes between riparian poplars and their fluvial environment. We have explored the possibility that the modification of the hydrogeomorphological environment exerted, in particular, by the European black poplar (Populus nigra L.), increases its fitness and thus results in positive niche construction. We focus on the fundamental phases of dispersal, recruitment and establishment until sexual maturity of P. nigra by describing the hierarchy of interactions and the pattern of feedbacks between biotic and abiotic components. We explicitly relate the biological life cycle of P. nigra to the fluvial biogeomorphic succession model by referring to the ‘biogeomorphological life cycle’ of P. nigra. Finally, we propose new research perspectives based on this theoretical framework.
- Published
- 2014
8. Refinement of ALS point cloud through the assessment of bare-earth classification algorithms: the AYPONA Project case study.
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Simon, François-Xavier, Pascual, Alfredo M., Vautier, Franck, and Miras, Yannick
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AERIAL photography ,GEOGRAPHIC information systems ,FREEWARE (Computer software) - Published
- 2015
9. Tsunamis as geomorphic crises: Lessons from the December 26, 2004 tsunami in Lhok Nga, West Banda Aceh (Sumatra, Indonesia)
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Paris, Raphaël, Wassmer, Patrick, Sartohadi, Junun, Lavigne, Franck, Barthomeuf, Benjamin, Desgages, Emilie, Grancher, Delphine, Baumert, Philippe, Vautier, Franck, Brunstein, Daniel, and Gomez, Christopher
- Subjects
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TSUNAMIS , *BEACH erosion , *SEDIMENT transport , *GEOMORPHOLOGY , *BOULDERS , *SEDIMENTATION & deposition - Abstract
Abstract: Large tsunamis are major geomorphic crises, since they imply extensive erosion, sediment transport and deposition in a few minutes and over hundreds of kilometres of coast. Nevertheless, little is known about their geomorphologic imprints. The December 26, 2004 tsunami in Sumatra (Indonesia) was one of the largest and deadliest tsunamis in recorded human history. We present a description of the coastal erosion and boulder deposition induced by the 2004 tsunami in the Lhok Nga Bay, located to the West of Banda Aceh (northwest Sumatra). The geomorphological impact of the tsunami is evidenced by: beach erosion (some beaches have almost disappeared); destruction of sand barriers protecting the lagoons or at river mouths; numerous erosion escarpments typically in the order of 0.5–1.5 m when capped by soil and more than 2 m in dunes; bank erosion in the river beds (the retreat along the main river is in the order of 5–15 m, with local retreats exceeding 30 m); large scars typically 20–50 cm deep on slopes; dislodgement of blocks along fractures and structural ramps on cliffs. The upper limit of erosion appears as a continuous trimline at 20–30 m a.s.l., locally reaching 50 m. The erosional imprints of the tsunami extend to 500 m from the shoreline and exceed 2 km along riverbeds. The overall coastal retreat from Lampuuk to Leupung was 60 m (550,000 m2) and locally exceeded 150 m. Over 276,000 m3 of coastal sediments were eroded by the tsunami along the 9.2 km of sandy coast. The mean erosion rate of the beaches was ~30 m3/m of coast and locally exceeded 80 m3/m. The most eroded coasts were tangent to the tsunami wave train, which was coming from the southwest. The fringing reefs were not efficient in reducing the erosional impact of the tsunami. The 220 boulders measured range from 0.3 to 7.2 m large (typically 0.7–1.5 m), with weights from over 50 kg up to 85 t. We found one boulder, less than 1 m large, at 1 km from the coastline, but all the others were transported less than 450 m (<7 m a.s.l.). No fining landward boulder size distribution could be detected. The coincidence of different size modes, from boulders to fine sands, with independent spatial distributions, suggests that all the material was not transported in suspension, but rather by a combination of suspension and bed load transport. Finally, the spatial and size distributions of tsunami boulder deposits mostly depend on the location and characteristics of their source (coral reef, beach rock, platform, dams), together with clast and surface interference during transport. One year after, the coastal environment in northwest Sumatra is still in a post-tsunami dynamic. Thus, the difference between the largest tsunamis (height>30 m) and the moderate tsunamis (height<10 m) could be their long-term impact on coastal environments. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
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