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Faycal Rejiba - One of the best experts on this subject based on the ideXlab platform.

  • multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging a case study in the Alluvial Plain of the river seine france
    Hydrology and Earth System Sciences, 2017
    Co-Authors: Faycal Rejiba, Cyril Schampe, Antoine Chevalie, Enoi Deleplancque, Gaghik Hovhannissia, Julie Thiesso, Pierre Weill
    Abstract:

    Abstract. The La Bassee floodPlain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River basin (France). Preferential flows depend essentially on the heterogeneity of Alluvial Plain infilling, whose characteristics are strongly influenced by the presence of mud plugs (paleomeander clayey infilling). These mud plugs strongly contrast with the coarse sand material that composes most of the Alluvial Plain, and can create permeability barriers to groundwater flows. A detailed knowledge of the global and internal geometry of such paleomeanders can thus lead to a comprehensive understanding of the long-term hydrogeological processes of the Alluvial Plain. A geophysical survey based on the use of electromagnetic induction was performed on a wide paleomeander, situated close to the city of Nogent-sur-Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (six apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from lidar data but also its vertical extent and internal variability.

  • geophysical investigations of a paleochannel in the Alluvial Plain of the river seine france
    Near Surface Geoscience 2016 - 22nd European Meeting of Environmental and Engineering Geophysics, 2016
    Co-Authors: Faycal Rejiba, Antoine Chevalier, Benoit Deleplancque, G Hovahnnissian, Cyril Schamper, Julien Thiesson, Pierre Weill
    Abstract:

    The integrated water resources management of the La Bassee Alluvial Plain is a key point of the current PIREN Seine program (2015-2019), dedicated to the study of the Seine River basin. The understanding of the processes driving the rearrangement of the river network through time is an important issue linked to the hydrogeological and hydrological properties of the basin. This study focuses on a zone located 2 km west of Nogent-sur-Seine (France) in the southern part of the Seine basin. The purpose of this study is to delineate the paleo-channel geometry using geophysical methods on an area of approximately 1 ha. The meander lateral extension has been delineated by electrical conductivity measurements using electromagnetic induction system (EMI). The depth extension of the clayey layer has been constrained and estimated by means of electrical resistivity tomography (ERT) on a 400 m reference profile where a series of auger soundings exist. Both data types have been inverted and interpreted in order to estimate the thickness of the clay layer formed by the paleo-Seine riverbed.

Pierre Weill - One of the best experts on this subject based on the ideXlab platform.

  • multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging a case study in the Alluvial Plain of the river seine france
    Hydrology and Earth System Sciences, 2017
    Co-Authors: Faycal Rejiba, Cyril Schampe, Antoine Chevalie, Enoi Deleplancque, Gaghik Hovhannissia, Julie Thiesso, Pierre Weill
    Abstract:

    Abstract. The La Bassee floodPlain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River basin (France). Preferential flows depend essentially on the heterogeneity of Alluvial Plain infilling, whose characteristics are strongly influenced by the presence of mud plugs (paleomeander clayey infilling). These mud plugs strongly contrast with the coarse sand material that composes most of the Alluvial Plain, and can create permeability barriers to groundwater flows. A detailed knowledge of the global and internal geometry of such paleomeanders can thus lead to a comprehensive understanding of the long-term hydrogeological processes of the Alluvial Plain. A geophysical survey based on the use of electromagnetic induction was performed on a wide paleomeander, situated close to the city of Nogent-sur-Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (six apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from lidar data but also its vertical extent and internal variability.

  • geophysical investigations of a paleochannel in the Alluvial Plain of the river seine france
    Near Surface Geoscience 2016 - 22nd European Meeting of Environmental and Engineering Geophysics, 2016
    Co-Authors: Faycal Rejiba, Antoine Chevalier, Benoit Deleplancque, G Hovahnnissian, Cyril Schamper, Julien Thiesson, Pierre Weill
    Abstract:

    The integrated water resources management of the La Bassee Alluvial Plain is a key point of the current PIREN Seine program (2015-2019), dedicated to the study of the Seine River basin. The understanding of the processes driving the rearrangement of the river network through time is an important issue linked to the hydrogeological and hydrological properties of the basin. This study focuses on a zone located 2 km west of Nogent-sur-Seine (France) in the southern part of the Seine basin. The purpose of this study is to delineate the paleo-channel geometry using geophysical methods on an area of approximately 1 ha. The meander lateral extension has been delineated by electrical conductivity measurements using electromagnetic induction system (EMI). The depth extension of the clayey layer has been constrained and estimated by means of electrical resistivity tomography (ERT) on a 400 m reference profile where a series of auger soundings exist. Both data types have been inverted and interpreted in order to estimate the thickness of the clay layer formed by the paleo-Seine riverbed.

Cremin Émilie - One of the best experts on this subject based on the ideXlab platform.

  • Adaptations agroécologiques et mobilités face aux aléas hydromorphologiques et aux contraintes foncières dans la Plaine Alluviale du Brahmapoutre (Assam – Inde)
    'OpenEdition', 2022
    Co-Authors: Cremin Émilie
    Abstract:

    Cet article questionne les processus d’adaptations agroécologiques et les mobilités des communautés paysannes face aux aléas hydro-morphologiques et aux contraintes foncières imposées par l’État dans la Plaine Alluviale du Brahmapoutre en Assam (Inde). En effet, les États qui ont gouverné successivement la Plaine Alluviale du Brahmapoutre (royaume Ahom, Britanniques, Inde indépendante) ont aménagé des digues afin de maîtriser le fleuve et d’assurer l’intensification des productions rizicoles. Or, ces aménagements bouleversent les dynamiques fluviales. Les paysans adaptent leurs pratiques agricoles en développant notamment différents types de cultures du riz. Néanmoins, ils doivent aussi faire face aux inondations suite à des ruptures de digues imprévues. Leurs terres disparaissent érodées par le fleuve ou enfouies sous les dépôts de sable. Par conséquent, ils déplacent leurs villages sur les digues, les bourrelets alluviaux et s’approprient des terres agricoles souvent sans droits ni titres. Les contraintes foncières imposées par l’État limitent ces pratiques et la mobilité des jeunes vers les espaces urbains apparaît comme une nouvelle alternative pour les communautés rurales de cette Plaine densément peuplée.This article questions the processes of agro-ecological adaptation and the mobility of peasant communities in the face of hydro-morphological hazards and land constraints imposed by the State in the Brahmaputra Alluvial Plain in Assam (India). Indeed, the states which successively ruled the Alluvial Plain of the Brahmaputra (Ahom kingdom, British, independent India) have built dikes in order to control the river and ensure the intensification of rice production. However, these developments are disrupting river dynamics. Farmers are adapting their agricultural practices, notably by developing different types of rice crops. However, they also have to deal with flooding following unforeseen dike failures. Their land disappears eroded by the river or buried under sand deposits. As a result, they relocate their villages to dykes, Alluvial ridges and appropriate agricultural land often without rights or titles. The land constraints imposed by the state limit these practices and the mobility of young people to urban spaces appears as a new alternative for the rural communities of this densely populated Plain

  • Adaptations agroécologiques et mobilités face aux aléas hydromorphologiques et aux contraintes foncières dans la Plaine Alluviale du Brahmapoutre (Assam – Inde)
    'OpenEdition', 2020
    Co-Authors: Cremin Émilie
    Abstract:

    This article questions the processes of agro-ecological adaptation and the mobility of peasant communities in the face of hydro-morphological hazards and land constraints imposed by the State in the Brahmaputra Alluvial Plain in Assam (India). Indeed, the states which successively ruled the Alluvial Plain of the Brahmaputra (Ahom kingdom, British, independent India) have built dikes in order to control the river and ensure the intensification of rice production. However, these developments are disrupting river dynamics. Farmers are adapting their agricultural practices, notably by developing different types of rice crops. However, they also have to deal with flooding following unforeseen dike failures. Their land disappears eroded by the river or buried under sand deposits. As a result, they relocate their villages to dykes, Alluvial ridges and appropriate agricultural land often without rights or titles. The land constraints imposed by the state limit these practices and the mobility of young people to urban spaces appears as a new alternative for the rural communities of this densely populated Plain

Zhiquan Gu - One of the best experts on this subject based on the ideXlab platform.

  • distribution sources and potential risk of hch and ddt in soils from a typical Alluvial Plain of the yangtze river delta region china
    Environmental Geochemistry and Health, 2014
    Co-Authors: Wenyou Hu, Biao Huang, Yongcun Zhao, Zhiquan Gu
    Abstract:

    Spatial distribution, sources and potential health risks of organochlorine pesticides (OCPs), including hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in surface soils (n = 544) collected from a typical Alluvial Plain of the Yangtze River Delta region, China, were elucidated. Concentrations of ΣHCH and ΣDDT in soils ranged from less than the limit of detection (spatial distributions of ∑ILCRs were consistent with concentrations of OCPs in soils, while they were slight different for the different age groups. Adult females had the greatest risk of OCPs in soils, followed by children, while youths had the least risk. The ingestion of OCPs in soils was the more important route of exposure compared with dermal and inhalation exposures. The concentration of OCPs in soils, the particulate emission factor, the fraction of dermal exposure ratio, and the soil ingestion rate were the major contributing variables to total ILCRs according to sensitivity analyses.

Wenyou Hu - One of the best experts on this subject based on the ideXlab platform.

  • distribution sources and potential risk of hch and ddt in soils from a typical Alluvial Plain of the yangtze river delta region china
    Environmental Geochemistry and Health, 2014
    Co-Authors: Wenyou Hu, Biao Huang, Yongcun Zhao, Zhiquan Gu
    Abstract:

    Spatial distribution, sources and potential health risks of organochlorine pesticides (OCPs), including hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in surface soils (n = 544) collected from a typical Alluvial Plain of the Yangtze River Delta region, China, were elucidated. Concentrations of ΣHCH and ΣDDT in soils ranged from less than the limit of detection (spatial distributions of ∑ILCRs were consistent with concentrations of OCPs in soils, while they were slight different for the different age groups. Adult females had the greatest risk of OCPs in soils, followed by children, while youths had the least risk. The ingestion of OCPs in soils was the more important route of exposure compared with dermal and inhalation exposures. The concentration of OCPs in soils, the particulate emission factor, the fraction of dermal exposure ratio, and the soil ingestion rate were the major contributing variables to total ILCRs according to sensitivity analyses.