28 results on '"Cerdan, Olivier"'
Search Results
2. Lessons learnt on the impact of an unprecedented soil decontamination program in Fukushima on contaminant fluxes.
- Author
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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]
- Published
- 2023
- Full Text
- View/download PDF
3. Modelling forest fire and firebreak scenarios in a mediterranean mountainous catchment: Impacts on sediment loads
- Author
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Cerdan Olivier, Vandromme Rosalie, Grangeon Thomas, Lo Porto Antonio, and De Girolamo Anna Maria
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Mediterranean climate ,Environmental Engineering ,Runoff ,Forest fires ,0208 environmental biotechnology ,Drainage basin ,02 engineering and technology ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,Flood events ,Fires ,Wildfires ,Rivers ,SWAT ,Waste Management and Disposal ,Firebreaks ,0105 earth and related environmental sciences ,Hydrology ,geography ,geography.geographical_feature_category ,Flood myth ,Sediment ,General Medicine ,020801 environmental engineering ,Italy ,Erosion ,Soil erosion ,Environmental science ,Catchment area ,Firebreak ,Surface runoff - Abstract
Forests provide a number of ecological and hydrological services, for instance, contributing to decreased water and sediment yields through increased infiltration and reduced soil erosion. However, forest fires can turn positive forest services into drawbacks, enhancing surface runoff and soil erosion and damaging both hillslopes and downstream aquatic life in rivers. Therefore, appropriate mitigation strategies should be developed to limit these negative effects. Using a runoff and erosion model (the WaterSed model), we proposed forest fire and firebreak scenarios to analyse their respective effects on sediment loads. The model reproduced the measured discharge and sediment loads over an entire hydrological year, including 21 flood events occurring from November 2010 to May 2011 in a 72-km2 Mediterranean catchment (Celone catchment, Puglia, Italy). Eight different forest fire scenarios were then proposed. While the mean burnt areas remained below 2% of the total catchment area, forest fires significantly affected the sediment yield. Indeed, the sediment yield increased over the different forest fire scenarios, from 1.97 to 2.70 t ha−1.yr−1, corresponding to a 37% increase. At the flood-event scale, the sediment load after fire represented up to 324% of the unburnt catchment sediment load in the worst-case scenario. By using realistic firebreaks, the sediment load could be dramatically reduced, from 324% to 165%, in the worst-case scenario. Because rural catchments, such as the Celone catchment, are currently experiencing land abandonment, forested areas are expected to replace crops and expand in the future. This change will likely increase forest ecological services, which may, however, be punctually balanced by negative fire effects. More studies addressing the global impacts of forest growth, fires and firebreaks on sediment transfers are therefore needed in similar environments.
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- 2020
4. The impact of typhoons on sediment connectivity: lessons learnt from contaminated coastal catchments of the Fukushima Prefecture (Japan)
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Chartin, Caroline, Evrard, O., Laceby, J. Patrick, Onda, Yuichi, Ottlé, Catherine, Lefevre, Irène, Cerdan, Olivier, 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 de Tsukuba = University of Tsukuba, Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), ANR-11-RSNR-0002,AMORAD,AMORAD1(2011), 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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flooding ,soil erosion ,storm events ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,radiocesium 16 ,sediment contamination ,[SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology - Abstract
International audience; Sediment connectivity characterizes the physical transfer of sediment through different geomorphic compartments in catchments due to sediment detachment, transport and deposition. Quantifying and modelling sediment connectivity is therefore a key prerequisite to improving our understanding of the dispersion of particle-borne contaminants, especially in catchments exposed to highly erosive climates. The objective of this study is to provide novel insights into typhoon impacts on sediment connectivity from hillslopes to rivers. The dispersion of particle-bound caesium-137 (Cs-137) was investigated in two coastal catchments draining the main contamination plume from the Fukushima Daiichi Nuclear Power Plant accident. Five sampling campaigns were carried out from November 2011 to November 2015, after each typhoon season. The spatial and temporal evolution of Cs-137 contamination was investigated through the calculation of Cs-137 enrichment ratios in sediment relative to nearby soils. Rainfall erosivity (EI30) associated with the main typhoons that occurred prior to each sampling campaign were computed, mapped, and finally used to improve a topographic-based index of connectivity. From 2011 to 2015, mean contamination levels in Mano and Niida catchments decreased from 11.9kBqkg(-1) to 3.3kBqkg(-1) and from 34.1kBqkg(-1) to 8.0kBqkg(-1), respectively. Regional mean EI30 ranged from 262MJmmha(-1)h(-1) for typhoon Jelawat (in 2012) to 1695MJmmha(-1)h(-1) for typhoon Roke (in 2011). Typhoons Roke (2011) and Etau (2015) showed the highest connectivity from contaminated sources to the rivers, and induced a significant export of sediment to the ocean. In 2013 a slight increase in Cs-137 levels in river sediments occurred, likely resulting from initial decontamination works and the occurrence of two consecutive typhoons. Importantly, this research provides new insights into the connectivity of the main sources of sediments contaminated with radiocaesium in Fukushima Prefecture and their temporal evolution, which will help with ongoing decontamination efforts.
- Published
- 2017
5. A comparison of management approaches to control muddy floods in central Belgium, northern France and southern England
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Cerdan, Olivier, Chauvet, Mehdi, Le Bissonnais, Yves, Raclot, Damien, Andrieux, Patrick, Bielders, Charles, Evrard, Olivier, Heitz, C., Liégeois, M., Boardman, J., Vandaele, Karel, Auzet, A.-V., Van Wesemael, Bas, 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), Département de Géographie (UCL GEO), Université Catholique de Louvain = Catholic University of Louvain (UCL), 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 Louis Pasteur - Strasbourg I, École Nationale des Travaux Publics de l'État (ENTPE), École Nationale des Travaux Publics de l'État (ENTPE)-Ministère de l'Ecologie, du Développement Durable, des Transports et du Logement, University of Oxford [Oxford], Watering van Sint-Truiden, Interbestuurlijke samenwerking Land en Water, Fonds pour la formation à la Recherche dans l’Industrie et l’Agriculture (F.R.I.A.), Belgium ., 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)-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), University of Oxford, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut de Recherche pour le Développement (IRD [ Madagascar])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Laboratoire d'étude des interactions entre sols, agrosystèmes et hydrosystèmes (LISAH), Institut National de la Recherche Agronomique (INRA), Earth and Life Institute [Louvain-La-Neuve] (ELI), Université Catholique de Louvain (UCL), 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), Institut de Recherches Subatomiques (IReS), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)
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010504 meteorology & atmospheric sciences ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Soil Science ,Buffer strip ,Development ,01 natural sciences ,stakeholders ,environmental management ,Muddy floods ,Retention basin ,Environmental Chemistry ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,Environmental planning ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,General Environmental Science ,Hydrology ,soil erosion ,Spatial mismatch ,Flood myth ,business.industry ,Flooding (psychology) ,agri-environmental measures ,04 agricultural and veterinary sciences ,15. Life on land ,flooding of properties ,6. Clean water ,Flood control ,Geography ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Agriculture ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,business ,Surface runoff - Abstract
International audience; Muddy floods, i.e. water flowing from agricultural fields and carrying large quantities of soil, affect routinely numerous municipalities of central Belgium, northern France and southern England. A comparison of flood frequency between different European regions is difficult, because of the lack of a uniform and official database as well as the landscape heterogeneity of administrative entities. AgriEnvironmental Measures (AEMs; e.g. grass buffer strips) can contribute to the control of muddy floods but their installation is voluntary and depends therefore on farmers’ willingness. Actions to increase awareness and to inform the farmers proved to increase drastically their participation rate in AEM programmes. In all the studied regions, flood prone areas are increasingly taken into account to define land approved for development. Moreover, several schemes for the control of muddy floods have also been proposed at the regional scale. However, there is a spatial mismatch between the scale at which muddy floods are triggered (small catchment scale) and the scale at which public authorities can operate (municipality, grouping of municipalities, delineated flood prone areas, river basin). In future, beside curative measures (e.g. retention ponds and dams), farming techniques preventing runoff and erosion in the field (e.g. conservation tillage) should be encouraged. This could be achieved by the creation of a new AEM. Moreover, guidelines for the location of AEMs could usefully be introduced. Existing flood control schemes should also be systematically carried out by catchment agencies including legal, environmental and financial expertise. These agencies should be set up for local groupings of municipalities and provide them technical assistance to equip the flood prone areas and carry out maintenance of the implemented control measures.
- Published
- 2010
6. Soil erosion rates (particulate and dissolved fluxes) variations in a temperate river basin
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Cerdan, Olivier, Gay, Aurore, Négrel, Philippe, Petelet-Giraud, Emmanuelle, Salvador-Blanes, Sébastien, Degan, Francesca, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours, AELB, European Geosciences Union, and Université de Tours (UT)
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Loire ,dissolved solid fluxes ,soil erosion ,Sediment Fluxes ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology - Abstract
International audience; Soil erosion is one of the major drivers of landscape evolution in Western Europe. However, depending on the land use characteristics and on the geological and topographical settings, miscellaneous forms of erosion may lead to a very diverse morphological evolution. To understand these landscape evolutions different scientific questions remain to be answered or quantified. The main difficulty arises from the nonlinear interactions between different erosional processes that act at different temporal and spatial scales. This study proposes to investigate different datasets describing particulate and dissolved sediment fluxes within a French River basin (The Loire River) at different spatial scales and at temporal scales ranging from the flood event to several decades.The particulate sediment load values at the outlet of the catchments range from 2.5 102 to 8.6 105 t yr-1, and the sediment yield values range from 2.9 to 32.4 t km 2 yr-1. Sediment exports from the Loire and Brittany river basins are low compared with mountainous regions and European exports. However, a strong spatial variability within this territory exists. The expected results on the sediment yield spatial pattern distribution and the correlation between SY values and basin sizes are not observed. An analysis of the sediment yield values at different time steps shows a strong effect of the seasonal availability of detached particles to be transported. High concentrations of suspended sediments during the winter and lower values during the summer and autumn are observed. Inter-annual variations are also observed, with export values varying by a factor 2 to 10 between years for one catchment. The influence of rainfall on the sediment exports is predominant, but investigations on physical characteristics of each catchment (e.g., lithology, slope, land use) are required to better understand the production and transfer processes within a drainage basin. These inter-annual variations imply that long-term data are required to provide mean SY values representative of the catchment functioning. From our calculations, 18 complete years of data are required to obtain a mean sediment yield value with less than 10% of variation on average around the mean.The specific dissolved fluxes vary from 13.7 to 199.9 t.km-2. t yr-1. Contrary to particulate matters, the impact of the lithology is illustrated by higher total dissolved solid fluxes on limestone catchments compared with graniteous or schisteous catchments. Nitrates and ammonium are indicators of anthropogenic perturbation and their fluxes vary respectively from 0.4 to 31.4 t.km-2. yr-1 and from 7.8*10-3 to 7.7 t.km-2. yr-1 and evolve differently according to land uses: nitrates fluxes are lower in the upstream Loire and higher downstream in the region where agricultural pressure is higher.The analysis of these datasets at different spatial and temporal scales permits to identify some of the dominant processes, and also to distinguish natural from anthropogenic influences. Concerning upland physical soil surface erosion rates, we find that the average travel distance of eroded particles may be limited, implying a strong decrease in physical erosion rates when moving from the local scale (m²) to the river basin scale (> 103 km²). Chemical erosion rates are less sensitive to scale and can either decrease or increase with increasing area in function of lithology, land management and topography. The results also highlight the predominant role of surface connectivity to characterize the fraction of sediment exported out of river drainage areas by physical soil surface erosion. For the export of dissolved sediment originating from weathering processes, the catchment physiography and connectivity does no longer play the dominant role. A direct link between soil production rates and exported dissolved fluxes tends to show that, contrary to the suspended particles, which are transport-limited, the dissolved matter seems to be supply-limited.
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- 2015
7. Application of strontium isotope measurements to trace sediment sources in an upstream agricultural catchment (Loire River basin, France)
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Le Gall, Marion, Evrard, Olivier, Thil, François, Foucher, Anthony, Sébastien, Salvador-Blanes, Cerdan, Olivier, Ayrault, Sophie, 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), Géochrononologie Traceurs Archéométrie (GEOTRAC), GéoHydrosystèmes COntinentaux (GéHCO EA6293), Université de Tours (UT), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Evrard, Olivier, 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)-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 Tours
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[SDE] Environmental Sciences ,end-members ,soil erosion ,[SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,[SDE.MCG]Environmental Sciences/Global Changes ,[SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study ,[SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment ,mixing models ,[SDE.MCG] Environmental Sciences/Global Changes ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[SDE]Environmental Sciences ,[SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology ,87Sr/86Sr isotopic ratio ,[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 of land degradation in agricultural areas. It accelerates the supply of sediment to the rivers and degrades water quality. To limit those impacts and optimize management programs in such areas, sources of sediment need to be identified and sediment transport to be controlled. Here, we determined the sources of suspended sediment in the Louroux (24 km$^2$ , French Loire River basin), a small catchment representative of lowland cultivated environments of Northwestern Europe. In this catchment, channels have been reshaped and 220 tile drain outlets have been installed over the last several decades. As a result, soil erosion and sediment fluxes have increased drastically. The variation of 87Sr/86Sr ratios, driven by the weathering of rocks with different ages and chemical composition , may reflect the mixing of different sediment sources. Strontium isotopic ratios (87Sr/86Sr) were therefore determined in potential soil sources, suspended particulate matter (SPM) and a sediment core sampled in the Louroux Pond at the catchment outlet.
- Published
- 2015
8. Quantification of bank erosion in a drained agricultural lowland catchment.
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Foucher, Anthony, Salvador‐Blanes, Sébastien, Vandromme, Rosalie, Cerdan, Olivier, and Desmet, Marc
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RIPARIAN areas ,STREAM channelization ,GEOLOGICAL cross sections ,SOIL erosion ,FARMS - Abstract
The long-term and current volumes of sediment exported from stream banks were calculated as potential sources of sediment in a large pond located at the catchment outlet of a small agricultural lowland basin strongly affected by anthropogenic pressure in France. Bank erosion was measured over a short period using a network of erosion pins along a small stream (1400 m long) to quantify the material exported during a single winter (2012-2013). The material exported by this same stream over the last 69 years was quantified using an original approach involving the comparison of a compilation of three-dimensional historical stream redesign plans that date back to 1944 with the state of the banks in 2013 (differential global positioning system and LiDAR data). The results suggest that a global trend of material loss along the stream banks monitored by erosion pins, with an average erosion rate of 17.7 mm year
−1 and an average volume of exported material of 75 t km−1 . Over 69 years, this same stream exported an average of 36 t km−1 year−1 , and the average loss of material from the banks throughout the whole catchment was estimated to be 14 t km−1 year−1 . The contribution of bank material to the filling of the pond over the last 10 years is between 46% and 52% based on an extrapolation of erosion pin dynamics or between 27% and 30% based on the comparison of LiDAR data to the average historical profile extrapolated for the catchment. These results suggest that bank erosion represents a major source of sediment in degraded waters in traditionally understudied agricultural lowland catchments, where anthropogenic pressures are high. [ABSTRACT FROM AUTHOR]- Published
- 2017
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9. 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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- *
FOREST fire management , *FOREST fires , *SOIL erosion , *EROSION , *SEDIMENTS , *POST-fire forests - Abstract
[Display omitted] • MUSLE is able to predict sedimentary response and mitigation measures in burnt areas. • High-severity fire increase soil erosion and sediment load at the basin scale. • Emergency stabilization and soil erosion barriers are effective to reduce soil erosion. • SWAT model may be a post-fire management decision tool. The present paper contributes to bridging the gaps in modelling post-fire impact and mitigation measures on soil erosion. The specific aims were to predict the effects of forest fires and post-fire mitigation measures on runoff and specific sediment yield (SSY) in a river basin (Celone, S-E Italy). The Soil and Water Assessment Tool model, calibrated with field observations, was used to evaluate runoff and SSY for the current land use (baseline) and six post-fire scenarios. From 1990 to 2011, at the basin scale, the average annual SSY was 5.60 t ha- 1yr−1 (SD = 3.47 t ha-1yr−1). 20% of the total drainage area showed a critical value of SSY (>10 t ha−1 yr−1). The effects of different fire-severity levels were predicted for one year after the fire, acting on a limited area (2.3% of the total basin area). At the basin scale, the post-fire effect on surface runoff was negligible for all scenarios (<0.4%), and the impact on SSY increased from 5.86 t ha−1 yr−1 up to 12.05 t ha−1 yr−1. At the subbasin scale, the post-fire logging scenario showed the highest increase of soil loss (SSY increased from 9.48 t ha−1 yr−1 to 57.40 t ha−1 yr−1). Post-fire mitigation treatments like straw mulching and erosion barriers effectively reduced soil erosion in high- and moderate-severity fires (19.12 t ha-1yr−1 and 20.93 t ha−1 yr−1, respectively). At the hydrological response unit level, the SSY estimated for the forest in the baseline ranged from 1.18 t ha- 1yr−1 to 2.04 t ha−1 yr−1. SSY increased more than one order of magnitude for the high-severity fire scenarios and ranged from 4.33 to 6.74 t ha−1 yr−1 in the very low-severity fire scenario, underlining the scale effect from the HRU to the basin scale. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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10. Renewed soil erosion and remobilisation of radioactive sediment in Fukushima coastal rivers after the 2013 typhoons.
- Author
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Evrard, Olivier, Chartin, Caroline, Yuichi Onda, Lepage, Hugo, Cerdan, Olivier, Lefèvre, Irène, and Ayrault, Sophie
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SOIL erosion ,RADIOACTIVE pollution ,TYPHOONS ,FUKUSHIMA Nuclear Accident, Fukushima, Japan, 2011 ,COASTAL plains ,DECONTAMINATION (From gases, chemicals, etc.) ,RIVERS - Abstract
Summer typhoons and spring snowmelt led to the riverine spread of continental Fukushima fallout to the coastal plains of Northeastern Japan and the Pacific Ocean. Four fieldwork campaigns based on measurement of radioactive dose rates in fine riverine sediment that has recently deposited on channel bed-sand were conducted between November 2011 and May 2013 to document the spread of fallout by rivers. After a progressive decrease in the fresh riverine sediment doses rates between 2011 and early spring in 2013, a fifth campaign conducted in November 2013 showed that they started to increase again after the occurrence of violent typhoons. We show that this increase in dose rates was mostly due to remobilization of contaminated material that was temporarily stored in river channels or, more importantly, in dam reservoirs of the region during the typhoons. In addition, supply of particles from freshly eroded soils in autumn 2013 was the most important in areas where decontamination works are under progress. Our results underline the need to monitor the impact of decontamination works and dam releases in the region, as they may provide a continuous source of radioactive contamination to the coastal plains and the Pacific Ocean during the coming years. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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11. Contribution of diffuse hillslope erosion to the sediment export of French rivers
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Cerdan, Olivier, Delmas, Magalie, Négrel, Philippe, Mouchel, Jean-Marie, Petelet-Giraud, Emmanuelle, Salvador-Blanes, Sébastien, and Degan, Francesca
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SOIL erosion , *SEDIMENT transport , *LANDSCAPES , *SEDIMENTS - Abstract
Abstract: Soil erosion is one of the major drivers of landscape evolution in Western Europe. However, depending on the land use characteristics and on the geological and topographical settings, miscellaneous forms of erosion may lead to a very diverse morphological evolution. A key element is the connection between the hillslope and the river. In this context, the objective of this study is to investigate to what extent eroded soil particles contribute to river sediment exports for the major French basins. The hillslope erosion rates are deduced from a distributed pan-European assessment of hillslope, rill, and interrill erosion by water, which was quantified by interpolation of erosion plot data as a function of topographical, land use, and pedological parameters. Sediment fluxes were mainly assessed from the French river quality database using an improved rating curve approach from the daily discharge data (IRCA), which allows estimation of the mean annual suspended sediment load. A similar approach based on the same datasets was used to calculate the mean annual dissolved load over the same period. The resulting mean annual suspended sediment loads show that French rivers export approximately 50 Mt of sediments per year to the seas, including ca. 17 Mt as particulate matter, corresponding to a specific sediment yield of ca. 0.4tha−1 yr−1. No relationship was found between the mass of the exported sediment and the size of the drainage basins, but large differences were observed between the different basins. For the Seine river basin and the Rhône river basin, the estimated average gross erosion rates are comparable, with ca. 1.14tha−1 yr−1 for the Rhone and ca. 1.80tha−1 yr−1 for the Seine. In contrast, the Rhône exports ca. 10 times more than the Seine River. The ratio of gross erosion to sediment exports calculated in this work ranges from 6.8% for the Seine to more than 100% for the Rhône. To explain these variations, we propose the use of indices that represent the landscape patchiness and connectivity. [Copyright &y& Elsevier]
- Published
- 2012
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12. Reliability of an expert-based runoff and erosion model: Application of STREAM to different environments
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Evrard, Olivier, Cerdan, Olivier, van Wesemael, Bas, Chauvet, Mehdi, Le Bissonnais, Yves, Raclot, Damien, Vandaele, Karel, Andrieux, Patrick, and Bielders, Charles
- Subjects
- *
SOIL erosion , *RUNOFF irrigation , *LOESS , *WATERSHEDS - Abstract
Abstract: During the last decades, the European loess belt has been confronted with a significant increase in environmental problems due to erosion on agricultural land. Spatially distributed runoff and erosion models operating at the catchment scale are therefore needed to evaluate the impact of potential mitigation measures. Expert-based models offer an alternative solution to process-based and empirical models, but their decision rules are only valid for the local conditions for which they have been derived. The STREAM model, which was developed in Normandy (France), has been applied in two Belgian catchments having a similar soil texture, as well as in a catchment of southern France differing by soil, land use and climate characteristics. The performance of hydrological models can be assessed for instance by calculating the Nash–Sutcliffe efficiency criterion (E NS). When applied to Belgium, the model results are satisfactory to good after an adaptation of the decision rules (0.90< E NS <0.93 for runoff predictions and 0.85< E NS <0.89 for erosion predictions). Given the important environmental differences between Normandy and southern France, the model rules were also adapted for application in the latter environment. Unfortunately, the quality of runoff predictions was insufficient to simulate erosion in southern France. In conclusion, STREAM is a reliable model providing satisfactory runoff and erosion predictions in the regions where hortonian overland flow dominates. Nevertheless, an adaptation of decision rules based on local multi-scale (plot, field, catchment) data is needed, before running the model. STREAM can then serve as a decision support tool to design for instance flood control measures. [Copyright &y& Elsevier]
- Published
- 2009
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13. Regional soil erosion risk mapping in Lebanon
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Bou Kheir, Rania, Cerdan, Olivier, and Abdallah, Chadi
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- *
SOIL erosion , *LAND degradation , *WATER pollution , *LANDSCAPES - Abstract
Abstract: Soil erosion by water is one of the major causes of land degradation in Lebanon. The problem has not yet been treated in detail although it affects vast areas. This study elaborates a model for mapping soil erosion risk in a representative area of Lebanon at a scale of 1:100,000 using a spatial database and GIS. First, three basic maps were derived: (1) runoff potential obtained from mean annual precipitation, soil-water retention capacity and soil/rock infiltration capacity; (2) landscape sensitivity based on vegetal cover, drainage density and slope; and (3) erodibility of rock and soil. Then two thematic maps were derived: potential sensitivity to erosion obtained from the runoff potential and landscape sensitivity maps, and erosion risk based on the potential erosion and erodibility maps. The risk map corresponds well to field observations on the occurrence of rills and gullies. The model used seems to be applicable to other areas of Lebanon, constituting a tool for soil conservation planning and sustainable management. [Copyright &y& Elsevier]
- Published
- 2006
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14. Analysis of off-site economic costs induced by runoff and soil erosion: Example of two areas in the northwestern European loess belt for the last two decades (Normandy, France).
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Patault, Edouard, Ledun, Jérôme, Landemaine, Valentin, Soulignac, Arnaud, Richet, Jean-Baptiste, Fournier, Matthieu, Ouvry, Jean-François, Cerdan, Olivier, and Laignel, Benoit
- Subjects
COST effectiveness ,SOIL erosion ,RUNOFF ,TECHNICAL reports ,RUNOFF analysis ,LAND management - Abstract
While soil erosion and runoff physical processes and socio-environmental impacts are widely addressed in the literature, few studies have focused on the economical dimension. However, it is essential to consider this dimension to conduct appropriate land use management policies. Erosion and runoff are known to result into on-site and off-site impacts. A fully exhaustive analysis of erosion and runoff economic costs may be difficult and ambitious due to the low availability of the data and considering that some issues are still unevaluated in the literature (cost of public policies to prevent erosion and runoff impacts, prohibition of drinking water due to turbidity, etc.). In this study, we chose to analyze the main off-site economic costs induced by these processes in two specific areas located in the northwestern European loess belt (Normandy, France). We quantified avoidance and social damages over the last 25 years through a global and retrospective analysis of financial databases provided by regional or local authorities (water agencies, departmental councils, reinsurance, drinking water companies, transport infrastructures managers) and literature review (scientific articles and technical reports). Our analysis suggested that from 1995 to 2017, the total damages cost ranged from 611 to 721 M€. Off-site avoidance damage costs accounted for almost 2/3 of the total expenditure. In the Seine-Maritime area, the mean cost was evaluated to 4 319 € yr
−1 km−2 and to 868 € yr−1 km−2 in the Eure area. Even if we tried to be as exhaustive as possible some off-site economic costs remained unknown. It appeared that more research is necessary for the scientific community to get a full picture of off-site economic costs induced by erosion and runoff. • Off-site economic costs of runoff and erosion were quantified through an analysis of public expenditures. • The total avoidance damages cost ranged from 375 to 485 M€. • The total social damages cost reached 236 M€. • The mean cost of erosion and runoff off-site impacts was estimated to 868 and 4319 € yr−1 km−2 . [ABSTRACT FROM AUTHOR]- Published
- 2021
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15. 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, Maniere, Louis, Grangeon, Thomas, Bakyono, Jean-Paul, and Desmet, Marc
- Subjects
SOIL erosion ,BODIES of water ,CHEMICAL decomposition ,LAKE sediments ,AGRICULTURAL processing - 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.)
- Published
- 2017
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16. 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
- Subjects
- *
AGRICULTURAL pollution , *SOIL erosion , *EROSION , *GEOMORPHOLOGY , *WATERSHEDS , *SOIL depth , *SOIL topography - Abstract
A major challenge in geomorphology is reconciling the disparity between runoff coefficients and erosion rates from the field to the catchment scale. In the European loess belt, a decrease of runoff coefficients and erosion rates occurs with increasing spatial scales. Indeed, it is important to understand the scale dependency of run-off and erosion to manage the off-site impacts of accelerated soil erosion. Accordingly, a continuous simulation of the scale dependency of runoff and erosion, from the field scale to the catchment scale (100 – 1000 km²) was conducted with the Water and Sediment (WaterSed) model for two catchments (Andelle-756 km², and Austreberthe-214 km²) over 12 years (>1000 events). Scale effects were evident with a 100-fold decrease in runoff coefficients and sediment delivery ratios between the field scale and the catchment scale. In spite of a low variability of the annual rainfall (19%), the inter-annual variability of the runoff volume (37%) and erosion rates (92%) at catchment outlets were high. The inter-annual variability of runoff and erosion was closely linked to the number of extreme events per year and their distribution through the year, in particular during periods with highly crusted soil surface states. For these high magnitude events, a complex distributed modelling approach was not necessary as the ability of the soil surface and of the landscape to retain overland flows are largely exceeded. The seasonality of soil surface characteristics also affected the scale dependency of runoff and erosion, from the field scale to the catchment scale. However, this is only observed up to a certain spatial extent, i.e. where hillslope erosion processes are governed by hortonian overland flow. When saturation flows are generated, topography and soil depth become the dominant factors. Understanding runoff and sediment response at different scales should focus on the location and amount of runoff and sediment production within the catchment and the capacity of the downstream flow path to retain or transfer overland flow and sediment. Furthermore, this study demonstrates the need to implement model that represent both hortonian and saturation flows when simulating erosion events at the catchment scale. [ABSTRACT FROM AUTHOR]
- Published
- 2019
17. Hydrosedimentary behavior of a field combining surface drains and tile drains.
- Author
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Gaillot, Arthur, Salvador-Blanes, Sébastien, Cerdan, Olivier, Vanhooydonck, Pierre, Grangeon, Thomas, Desmet, Marc, and Delbart, Célestine
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- *
MEASUREMENT of runoff , *SUSPENDED sediments , *EROSION , *SOIL erosion , *TEMPERATE climate , *SOIL particles - Abstract
In agricultural fields, soil erosion is usually associated to surface runoff. However, in drained fields, tile drains are additional pathways for soil particles. Few studies have quantified erosion in drained fields and they mainly focused on tile drained fields, without considering fields combining surface and tile drainage. These studies show high inter-site and inter-annual variabilities that highlight the need for more annual quantifications of erosion in drained fields. Consequently, it is still difficult to quantify the relative importance of the factors affecting soil erosion in drained fields. In addition to a comprehensive review of the existing studies of erosion through drainage, this study aims at quantifying surface and subsurface erosion in a 5 ha cultivated field combining surface and tile drainage. Suspended sediments (SS) and water fluxes have been monitored during two years (2019–2020 and 2020–2021) at a high temporal resolution (1 min), both at the outlet of the tile drain network and at the outlet of the surface drainage rill. SS yield was 0.49 t ha−1 and 1.08 t ha−1 in 2019–2020 and 2020–2021, respectively. During 2019–2020 and 2020–2021, tile drainage contribution to the total runoff was 46% and 21%, respectively and its contribution to SS yield was 9% and 11%, respectively. High temporal resolution measurements of runoff and SS concentrations showed the suspended sediment concentration in the surface drain runoff only increase by 17% from the first to the second study year. Conversely, for tile drainage, average suspended sediment concentrations increased by 260%. These variations and the increase of surface runoff rate suggest a shift in water and sediment connectivity at the field scale. Cropping practices could have generated a slumping of the soil surface during the second year and, at the same time, the development of a macropore network in the subsoil. Cropping practices induced changes of surface horizon characteristics and their impact on the hydrosedimentary behavior of drained soils need to be further studied. This study confirms previous results concerning the temporal dynamics of SS exports in a drained context under temperate climate and adds a new quantification of hydrosedimentary fluxes in a surface and tile drained field separating surface drains and tile drains contributions. • High temporal resolution monitoring of surface and tile drain hydrosedimentary fluxes. • Suspended sediment yield was 0.49 t ha−1 and 1.08 t ha−1, in 2019–2020 and 2020–2021. • Tile drains contribute up to 11% of the suspended sediment load. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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18. 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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19. Impacts of farmland decontamination on 137Cs transfers in rivers after Fukushima nuclear accident: Evidence from a retrospective sediment core study.
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Chalaux-Clergue, Thomas, Foucher, Anthony, Chaboche, Pierre-Alexis, Hayashi, Seiji, Tsuji, Hideki, Wakiyama, Yoshifumi, Huon, Sylvain, Vandromme, Rosalie, Cerdan, Olivier, Nakao, Atsushi, and Evrard, Olivier
- Published
- 2024
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20. Modelling the impact of land use change and rainfall seasonality on sediment export from an agricultural catchment of the northwestern European loess belt
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Evrard, Olivier, Nord, Guillaume, Cerdan, Olivier, Souchère, Véronique, Le Bissonnais, Yves, and Bonté, Philippe
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- *
LAND use , *RAINFALL , *SEDIMENTS , *SOIL erosion , *CESIUM isotopes , *RESERVOIR sedimentation - Abstract
Abstract: Soil erosion leads to important environmental problems (e.g. muddy floods, reservoir sedimentation) in cultivated areas of the European loess belt. This study aimed to determine the impact of rainfall seasonality and land use change on soil erosion over the last 40 years in a 94-ha cultivated catchment of Normandy (France). To this end, scenarios representative of the different land use conditions were simulated using the STREAM expert-based erosion model. A 13 years long sequence of rainfall events was run with this model. Results showed that erosion increased dramatically after land consolidation (+168% on average). Interannual variability of erosion is important. After land consolidation, 79% of erosion was observed in summer and autumn, even though these seasons only accounted for 58% of annual rainfall kinetic energy. The bulk of erosion was hence produced by a few intense thunderstorms during this period. Thunderstorms correspond to 5% of rainfall events and to 15% of the total rainfall depth, but they generate 51% of total annual erosion after land consolidation (and up to 57% of erosion before land consolidation). Confrontation of the STREAM model outputs with the erosion rates modelled based on Cs-137 measurements suggested that soil redistribution within the catchment was very high but that sediment exports from the catchment remained limited (sediment delivery ratio between 1% and 10%). Local erosion rates derived from Cs-137 measurements showed an important and organised spatial variability, but erosion rates integrated over larger areas remained in the same order of magnitude as those simulated by the STREAM model or were slightly higher. Water erosion would hence not be the only process generating erosion within this catchment. In this context, our results show that tillage erosion cannot be neglected to calculate the sediment budget over several decades. [Copyright &y& Elsevier]
- Published
- 2010
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21. Quantifying sediment sources in a lowland agricultural catchment pond using 137Cs activities and radiogenic 87Sr/86Sr ratios.
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Le Gall, Marion, Evrard, Olivier, Foucher, Anthony, Laceby, J. Patrick, Salvador-Blanes, Sébastien, Thil, François, Dapoigny, Arnaud, Lefèvre, Irène, Cerdan, Olivier, and Ayrault, Sophie
- Subjects
- *
SOIL erosion , *WATER quality , *RESERVOIRS , *RIVER channels , *LAND management - Abstract
Soil erosion often supplies high sediment loads to rivers, degrading water quality and contributing to the siltation of reservoirs and lowland river channels. These impacts are exacerbated in agricultural catchments where modifications in land management and agricultural practices were shown to accelerate sediment supply. In this study, sediment sources were identified with a novel tracing approach combining cesium ( 137 Cs) and strontium isotopes ( 87 Sr/ 86 Sr) in the Louroux pond, at the outlet of a lowland cultivated catchment (24 km 2 , Loire River basin, France) representative of drained agricultural areas of Northwestern Europe. Surface soil (n = 36) and subsurface channel bank (n = 17) samples were collected to characterize potential sources. Deposited sediment (n = 41) was sampled across the entire surface of the pond to examine spatial variation in sediment deposits. In addition, a 1.10 m sediment core was sampled in the middle of the pond to reconstruct source variations throughout time. 137 Cs was used to discriminate between surface and subsurface sources, whereas 87 Sr/ 86 Sr ratios discriminated between lithological sources. A distribution modeling approach quantified the relative contribution of these sources to the sampled sediment. Results indicate that surface sources contributed to the majority of pond (μ 82%, σ 1%) and core (μ 88%, σ 2%) sediment with elevated subsurface contributions modeled near specific sites close to the banks of the Louroux pond. Contributions of the lithological sources were well mixed in surface sediment across the pond (i.e., carbonate sediment contribution, μ 48%, σ 1% and non-carbonate sediment contribution, μ 52%, σ 3%) although there were significant variations of these source contributions modeled for the sediment core between 1955 and 2013. These fluctuations reflect both the progressive implementation of land consolidation schemes in the catchment and the eutrophication of the pond. This original sediment fingerprinting study demonstrates the potential of combining radionuclide and strontium isotopic geochemistry measurements to quantify sediment sources in cultivated catchments. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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22. Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting.
- Author
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Foucher, Anthony, Laceby, Patrick J., Salvador-Blanes, Sébastien, Evrard, Olivier, Le Gall, Marion, Lefèvre, Irène, Cerdan, Olivier, Rajkumar, Vignesh, and Desmet, Marc
- Subjects
- *
SEDIMENTS , *AGRICULTURAL water supply , *WATERSHEDS , *SOIL erosion , *LAND degradation , *WATER quality - Abstract
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 ( 137 Cs) concentrations were used to determine the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137 Cs 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 137 Cs 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 137 Cs 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. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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23. Land use and climate change effects on soil erosion in a semi-arid mountainous watershed (High Atlas, Morocco).
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Simonneaux, Vincent, Cheggour, Aouatif, Deschamps, Charles, Mouillot, Florent, Cerdan, Olivier, and Le Bissonnais, Yves
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- *
LAND use , *CLIMATE change , *SOIL erosion , *ARID regions , *WATERSHEDS - Abstract
The objective of this study was to simulate the evolution of soil erosion in a semi-arid mountainous watershed (225 km 2 , High Atlas Mountains, Morocco) under different scenarios of climate and land use change to the end of 21st century. Erosion plots monitored over four years showed spatially contrasted results. Most of the soils produced from 0.015 to 2.5 t ha −1 y −1 , whereas badlands produced 350 t ha −1 y −1 . The average sediment yield measured at the outlet during the same period was approximately 4 t ha −1 y −1 . The STREAM distributed erosion model was parameterized using these field measurements (infiltration rates and runoff sediment concentrations). The results showed an overall agreement between the modelled and measured annual cumulative sediment yields. Simulations of the ARPEGE meteorological model were used for the 1960–1990 and 2070–2100 periods. The changes between these two periods were downscaled using three different methods, decreasing annual precipitations by 10–14%, although with more rainfall in summer and fall. Climate change alone increased sediment yield by 4.7–10.1%. However, simulations showed that land use changes might potentially induce much larger changes in erosion (up to 250%), approximately proportional to the evolution of the extension of badlands. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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24. Improvement of surface flow network prediction for the modeling of erosion processes in agricultural landscapes
- Author
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Couturier, Alain, Daroussin, Joël, Darboux, Frédéric, Souchère, Véronique, Le Bissonnais, Yves, Cerdan, Olivier, and King, Dominique
- Subjects
- *
HISTORIC agricultural landscapes , *SOIL erosion , *SOIL temperature , *PREDICTION models , *HYDROLOGY , *GEOGRAPHIC information systems , *SOIL moisture - Abstract
Abstract: The modeling of soil erosion by water supposes an accurate and thorough understanding of the hydrology. Thus, it is critical to have a good delineation of the surface flow path. The flow network data are critical for important uses such as flood forecasting and watershed management. Geographic Information System (GIS) functions are able to compute a flow network directly from the digital elevation models. Because the flow directions are only based on the topography, the other factors controlling the flow directions are overlooked. In the agricultural areas, work such as tillage can have a large impact on the flow direction. We propose a 5-step procedure to account for such man-made features. The use of this procedure clearly improves the quality of the computed flow network. This procedure has been successfully implemented in a GIS and improves the prediction of surface flow and therefore improves water erosion modeling at the watershed scale. [Copyright &y& Elsevier]
- Published
- 2013
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25. Quantifying hydro-sedimentary transfers in a lowland tile-drained agricultural catchment.
- Author
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Grangeon, Thomas, Ceriani, Valeria, Evrard, Olivier, Grison, Aurélie, Vandromme, Rosalie, Gaillot, Arthur, Cerdan, Olivier, and Salvador-Blanes, Sébastien
- Subjects
- *
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]
- Published
- 2021
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26. 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
- Subjects
- *
FUNCTIONAL connectivity , *SEDIMENTS , *CROP allocation , *SOIL erosion , *MOLECULAR connectivity index , *LAND cover , *SOIL conservation , *SEDIMENT transport - 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. • First model comparison study to evaluate connectivity within models • No overall agreement between models for land use scenarios • Functional connectivity (rainfall forcing) more important than structural connectivity [ABSTRACT FROM AUTHOR]
- Published
- 2020
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27. Regional trends in eutrophication across the Loire river basin during the 20th century based on multi-proxy paleolimnological reconstructions.
- Author
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Foucher, Anthony, Evrard, Olivier, Huon, Sylvain, Curie, Florence, Lefèvre, Irène, Vaury, Véronique, Cerdan, Olivier, Vandromme, Rosalie, and Salvador-Blanes, Sébastien
- Subjects
- *
TWENTIETH century , *BODIES of water , *EUTROPHICATION , *SEDIMENT analysis - Abstract
• Sediment cores were collected in ponds draining contrasted agricultural catchments. • Paleproductivity was reconstructed during the 20th century based on multiproxy sediment analysis. • Between 1950 and 1965 organic matter was mainly supplied by terrigenous sources. • After 1970, acceleration of primary production was recorded in water bodies • Autochthonous production was highly correlated to the use of N fertilizers for the 1950–1990 period. Excessive inputs of sediment and acceleration of primary production have been observed worldwide in a large number of water bodies. Human-environment interactions were recognized as one of the main drivers of this evolution during the 20th century with the occurrence of major landscape changes and a greater use of agricultural inputs. In this study, we used paleo-production proxies such as chlorophyll-a, organic matter properties (TOC and TN concentrations, δ13C and δ15N) measured in sediment cores dated with fallout 210Pb ex and 137Cs activities for reconstructing changes in accumulation rates and sources of organic matter during the recent period of agricultural intensification (1920–2020). In order to record these changes at the regional scale, sediment cores were collected at the outlet of several headwater catchments (n = 9), covering a wide range of land covers / land uses across the Loire River basin (117,000 km²), France. The rates of sedimentary organic matter deposition in the studied water bodies accelerated from 1950 onwards (+48 %). Between 1950 and 1970, the signature of sedimentary organic matter indicates a dominant contribution of soil-derived inputs. This period corresponds to major landscape modifications across the basin (land consolidation, stream re-design, implementation of tile drains) driving a general acceleration of erosion rates. Then, from 1960 onwards, chlorophyll-a and C/N proxies indicate an increase in primary production coupled with a decrease of terrigenous supply in agricultural catchments. These proxies were strongly correlated to the agricultural inputs during the 1955–1990 period (e.g., r = 0.9 between chlorophyll-a content and N inputs), suggesting a progressive eutrophication of these reservoirs driven by increasing fertilizer use. During these 35 years, sedimentary organic matter deposition rates increased on average by 30 %. During the 1990s, despite a slight reduction in fertilizer use (−13 %), the paleo-production proxies (e.g. chlorophyll-a) still indicate a positive trend suggesting the contribution of another driving factor such as climate warming or again nutrient release from soils and sediments. In the absence of long term geochemical and sediment input monitoring, paleolimnological reconstructions provide a powerful tool to reconstruct past agricultural pressures in rural environments. This study illustrates the impact of intensive farming on water body siltation driven by varying sources of organic material during the 20th century. In addition, these results suggest that eutrophication processes of these reservoirs with contrasting land uses started during the 1960–1970 period and are still ongoing nowadays. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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28. Erosional response to land abandonment in rural areas of Western Europe during the Anthropocene: A case study in the Massif-Central, France.
- Author
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Foucher, Anthony, Evrard, Olivier, Chabert, Clément, Cerdan, Olivier, Lefèvre, Irène, Vandromme, Rosalie, and Salvador-Blanes, Sébastien
- Subjects
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RURAL geography , *SOIL erosion , *ARABLE land , *SOIL dynamics - Abstract
• Sediment cores were collected in two ponds of western Europe. • Land abandonment and soil erosion relationship was investigated during one century. • Arable lands have significantly decrease after WWII (85–95%). • Statistical decline of sediment inputs was observed (75–99%). Abandonment of agricultural land is widespread in many developed countries. These surfaces are projected to increase significantly worldwide during the 21th century. Identifying potential relationships between land abandonment and soil erosion dynamics over the long term (100 years) is therefore essential for predicting the environmental consequences of this extensive land use change. Accordingly, sediment cores were collected in two highland catchments of central France in order to reconstruct the change of sediment delivery during the last century. The results showed a substantial decline (71–78%) of rural population in both sites since 1900. This decrease occurred simultaneously with a sharp decline (85–95%) of the surface of arable land: previously cultivated areas were mainly converted into forests as the result of natural and anthropogenic processes. Consequently, sediment deliveries significantly decreased (75–99%) in both catchments. These trends were nevertheless interrupted by the implementation of afforestation works between 1945 and 1970 in one of the catchments. During these works, erosion rates increased three-fold because of extensive soil disturbance, and sediment delivery stabilized only 15 years after the onset of these management operations. Overall, this study demonstrates the long-term effect of land abandonment on soil erosion, which supplements the more widely reported acceleration trend of soil erosion because of agricultural intensification. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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