83 research outputs found
EUSEDcollab: a network of data from European catchments to monitor net soil erosion by water
As a network of researchers we release an open-access database (EUSEDcollab) of water discharge and suspended sediment yield time series records collected in small to medium sized catchments in Europe. EUSEDcollab is compiled to overcome the scarcity of open-access data at relevant spatial scales for studies on runoff, soil loss by water erosion and sediment delivery. Multi-source measurement data from numerous researchers and institutions were harmonised into a common time series and metadata structure. Data reuse is facilitated through accompanying metadata descriptors providing background technical information for each monitoring station setup. Across ten European countries, EUSEDcollab covers over 1600 catchment years of data from 245 catchments at event (11 catchments), daily (22 catchments) and monthly (212 catchments) temporal resolution, and is unique in its focus on small to medium catchment drainage areas (median = 43 km(2), min = 0.04 km(2), max = 817 km(2)) with applicability for soil erosion research. We release this database with the aim of uniting people, knowledge and data through the European Union Soil Observatory (EUSO)
EUSEDcollab: a network of data from European catchments to monitor net soil erosion by water
As a network of researchers we release an open-access database (EUSEDcollab) of water discharge and suspended sediment yield time series records collected in small to medium sized catchments in Europe. EUSEDcollab is compiled to overcome the scarcity of open-access data at relevant spatial scales for studies on runoff, soil loss by water erosion and sediment delivery. Multi-source measurement data from numerous researchers and institutions were harmonised into a common time series and metadata structure. Data reuse is facilitated through accompanying metadata descriptors providing background technical information for each monitoring station setup. Across ten European countries, EUSEDcollab covers over 1600 catchment years of data from 245 catchments at event (11 catchments), daily (22 catchments) and monthly (212 catchments) temporal resolution, and is unique in its focus on small to medium catchment drainage areas (median=43km2, min=0.04km2, max=817km2) with applicability for soil erosion research. We release this database with the aim of uniting people, knowledge and data through the European Union Soil Observatory (EUSO)
Soil erosion modelling: A bibliometric analysis
Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication\u27s CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper
Soil erosion modelling: A global review and statistical analysis
To gain a better understanding of the global application of soil erosion prediction models, we comprehensivelyreviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and2017. We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the re-gions within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv)how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To per-form this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. Theresulting database, namedâGlobal Applications of Soil Erosion Modelling Tracker (GASEMT)â, includes 3030 indi-vidual modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluatedand transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insightsinto the state-of-the-art of soil- erosion models and model applications worldwide. This database intends to sup-port the upcoming country-based United Nations global soil-erosion assessment in addition to helping to informsoil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is anopen-source database available to the entire user-community to develop research, rectify errors, andmakefutureexpansion
Soil erosion modelling: A global review and statistical analysis
To gain a better understanding of the global application of soil erosion prediction models, we comprehensively
reviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and
2017.We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the regions
within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv)
how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To perform
this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. The
resulting database, named âGlobal Applications of Soil ErosionModelling Tracker (GASEMT)â, includes 3030 individual
modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471
articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluated
and transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insights
into the state-of-the-art of soil- erosionmodels and model applicationsworldwide. This database intends to support
the upcoming country-based United Nations global soil-erosion assessment in addition to helping to inform
soil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is an
open-source database available to the entire user-community to develop research, rectify errors, andmake future
expansions
Soil erosion modelling: A bibliometric analysis
Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore,
soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion
hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics
that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed
bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted.
The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database
contains information about citation characteristics and publication type. Here, we investigated the impact of the
number of authors, the publication type and the selected journal on the number of citations. Generalized boosted
regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion
modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection
of the soil erosion model has the largest impact on the number of publication citations, followed by the
modelling scale and the publicationâs CiteScore. Some of the other GASEMT database attributes such as model
calibration and validation have negligible influence on the number of citations according to the BRT model.
Although it is true that studies that conduct calibration, on average, received around 30% more citations, than
studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a
clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore,
soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the
research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an
additional focus should be given to field measurements, model calibration, performance assessment and uncertainty
of modelling results. The results of this study indicate that these GASEMT database attributes had
smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest
that these attributes should be given additional attention by the soil erosion modelling community. This study
provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate
the influence of their paper
Firms' growth in frictional markets
This thesis lies in the fields of International Trade and Labor Economics and focuses on firms' growth. Firm dynamics play a key role in shaping aggregate outcomes. Understanding how firms grow and how they decline is thus crucial to understand aggregate growth, innovation, and the functioning of labor markets. One of the widely-recognized factors slowing down firms' growth is frictions, both on the product market and the labor market. On the one hand, information and contractual frictions between sellers and buyers preclude firms from reaching new buyers. On the other hand, labor market frictions, by increasing the costs to hire and dismiss workers, reduce the efficient reallocation of workers across firms, thereby slowing down firms' growth on domestic and foreign markets. This thesis analyzes the impact of those two types of frictions on firms' growth and survival.The first chapter identifies a causal impact of poaching a sales manager from other firms' labor force on a firm's ability to develop its international portfolio of clients. The two remaining chapters consider the effect of labor market frictions, and more specifically labor market policies, on firms' growth and survival. The second chapter analyses judge bias in labor courts and how it can affect the sued firms' growth prospects. The third chapter deals with sectoral agreements and highlights a mechanism by which large firms can use sectoral bargaining as an anti-competitive device.Cette thĂšse sâinscrit dans les domaines de lâĂ©conomie internationale et de lâĂ©conomie du travail, et porte sur la croissance des entreprises. Les dynamiques d'entreprises jouent un rĂŽle clĂ© dans la dĂ©termination des rĂ©sultats agrĂ©gĂ©s. Il est donc essentiel de comprendre comment les entreprises se dĂ©veloppent pour comprendre la croissance Ă©conomique, l'innovation et le fonctionnement du marchĂ© du travail. Les frictions, tant sur le marchĂ© des biens que sur le marchĂ© du travail, constituent l'un des facteurs ralentissant la croissance des entreprises. D'une part, les frictions informationnelles et contractuelles entre vendeurs et acheteurs empĂȘchent les entreprises d'acquĂ©rir de nouveaux acheteurs. D'autre part, les frictions sur le marchĂ© du travail, en augmentant les coĂ»ts d'embauche et de licenciement des travailleurs, limitent la rĂ©allocation efficace des travailleurs entre les entreprises, ce qui ralentit la croissance des entreprises sur les marchĂ©s nationaux et Ă©trangers. Cette thĂšse analyse l'impact de ces deux types de frictions sur la croissance et la survie des entreprises.Le premier chapitre identifie l'impact causal du dĂ©bauchage de commerciaux provenant d'entreprises rivales sur la capacitĂ© d'une entreprise Ă dĂ©velopper son portefeuille de clients Ă l'international. Les deux derniers chapitres portent sur l'effet des frictions du marchĂ© du travail, et plus particuliĂšrement sur l'effet des politiques du marchĂ© du travail, sur la croissance et la survie des entreprises. Le deuxiĂšme chapitre dĂ©crit les biais des juges dans les tribunaux du travail et comment ils peuvent affecter les perspectives de croissance des entreprises poursuivies. Le troisiĂšme chapitre traite des accords de branche et met en avant un mĂ©canisme par lequel les grandes entreprises peuvent utiliser la nĂ©gociation sectorielle comme un dispositif anticoncurrentiel
Analyse multi-Ă©chelle des processus dâĂ©rosion hydrique et de transferts sĂ©dimentaires en territoire agricole : exemple du bassin versant de la Canche (France)
Water erosion is a serious concern in global land degradation leading to multiple consequences: loss of arable lands, siltation of streams, mudflows. In France, the Hauts-de-France region is the most affected area, and soil loss can exceed 10 t ha-1 yr-1. Although hydro-sedimentary processes have been widely studied by the scientific community, there is still a lack of knowledge in the understanding of the spatio-temporal variabilities. Additionally, the effectiveness of recent erosion control policies so far cannot be quantified. This study proposes an analysis of the spatio-temporal variability of sedimentary transfer at different scaling (1-1000 kmÂČ), and an initial assessment of the effectiveness of management policies within a northern France catchment (the Canche river, 1274 kmÂČ). A high-frequency monitoring station was implemented at the outlet of a Canche sub-catchment (the Pommeroye, 0.54 kmÂČ) to quantify the hydro-sedimentary transfer over two contrasted hydrologic years. According to our results, sediment yield varies from 29.4 to 70 t km-2 yr-1. 40% of the flux is exported during 3 major erosive events (out of 48 recorded) and the forcing parameters are related to the duration and the amount of rainfall. In this sub-catchment, the centimeter-scale spatial prediction of the hydro-sedimentary transfer was carried out using the new soil erosion model WATERSED (BRGM) and the effectiveness of an anti-erosion management plan was quantified. Our results validate the operability of the model in this context. For a given event, sediment transfer can reach 76 t km-2 yr-1 in agricultural plots and are strongly depending on the soil surface state. A significant reduction (up to 84%) of sedimentary transfer by the anti-erosion plan was also observed. At the scale of the Canche catchment, the use of chemical and spectrocolorimetric tracers in a mixing model (Sed_Sat tool; USGS) evaluated the contributions of the Canche tributaries and sediment sources contributions (i.e. channel banks and soils; 30-70% respectively). Significant spatio-temporal variations have been observed and the results show a potential positive impact of the recent management policies. This study also shows that new tracers related to the specific signature of magnetic particles are promising in the context to trace soil erosion. For further analyses, this data could be included in sediment fingerprinting approaches. Thus, this study based on several spatio-temporal modalities and the coupling of experimentation and modelling improves our understanding of the Canche hydro-sedimentary dynamics. It provides essential results to guide the future erosion control policies.LâĂ©rosion hydrique est un processus majeur de dĂ©gradation des sols dans le monde avec des consĂ©quences multiples : perte de terres agricoles, envasement des cours dâeau, coulĂ©es boueuses. En France, la rĂ©gion Hauts-de-France est la zone la plus touchĂ©e par ces pertes en terres qui peuvent dĂ©passer les 10 t ha-1 an-1. Si les processus Ă lâorigine de ces transferts sĂ©dimentaires ont Ă©tĂ© largement Ă©tudiĂ©s par la communautĂ© scientifique ces derniĂšres annĂ©es, il reste nĂ©anmoins des verrous liĂ©s aux variabilitĂ©s spatio-temporelles. De plus, lâefficacitĂ© des politiques rĂ©centes de lutte contre lâĂ©rosion nâest pas quantifiĂ©e. Cette Ă©tude propose une analyse de la variabilitĂ© spatio-temporelle des transferts sĂ©dimentaires selon plusieurs Ă©chelles (1-1000 kmÂČ), et une premiĂšre Ă©valuation de lâefficacitĂ© des politiques dâamĂ©nagement au sein dâun bassin du Nord de la France (la Canche ; 1274 kmÂČ). Une station de mesure haute-frĂ©quence, a Ă©tĂ© implĂ©mentĂ©e Ă lâexutoire dâun sous-bassin versant de la Canche (la Pommeroye ; 0,54 kmÂČ) pour quantifier les transferts hydro-sĂ©dimentaires sur deux annĂ©es hydrologiques contrastĂ©es. Selon nos rĂ©sultats, les transferts varient de 29,4 Ă 70 t km-2 an-1. 40% du flux est exportĂ© au cours de 3 Ă©pisodes Ă©rosifs majeurs (sur 48 enregistrĂ©s) et les paramĂštres forçants sont liĂ©s Ă la durĂ©e dâun Ă©pisode pluvieux et la quantitĂ© de prĂ©cipitations. Sur ce mĂȘme bassin, la prĂ©diction spatiale Ă lâĂ©chelle centimĂ©trique des transferts hydro-sĂ©dimentaires a pu ĂȘtre effectuĂ©e via le nouveau modĂšle dâĂ©rosion des sols WATERSED (BRGM) et lâefficacitĂ© dâun plan dâamĂ©nagement de lutte contre lâĂ©rosion a Ă©tĂ© quantifiĂ©e. Nos rĂ©sultats permettent de valider lâopĂ©rabilitĂ© du modĂšle sur ce territoire. Les transferts sĂ©dimentaires Ă lâĂ©chelle du parcellaire agricole peuvent atteindre les 76 t km-2 pour un Ă©vĂšnement donnĂ© et sont influencĂ©s par lâĂ©tat de surface du parcellaire agricole. Une rĂ©duction significative (jusquâĂ 84%) des transferts par les amĂ©nagements dâhydraulique douce est Ă©galement observĂ©e. A lâĂ©chelle du bassin de la Canche, lâutilisation de traceurs chimiques et spectrocolorimĂ©triques dans un modĂšle de mĂ©lange (Sed_Sat ; USGS) a permis dâĂ©valuer dâune part les contributions des affluents de la Canche et dâautre part les contributions des sols et des berges (respectivement 30-70%). Des variations spatio-temporelles significatives ont pu ĂȘtre observĂ©es et les rĂ©sultats tendent Ă montrer un potentiel impact positif des politiques rĂ©centes dâamĂ©nagement du territoire. Cette Ă©tude montre Ă©galement que de nouveaux traceurs liĂ©s Ă la signature spĂ©cifique des particules magnĂ©tiques sont particuliĂšrement prometteurs dans ce contexte pour tracer un signal dâĂ©rosion des sols. A terme, ces donnĂ©es pourraient ĂȘtre incluses dans des approches sediment fingerprinting. Lâanalyse selon plusieurs modalitĂ©s spatio-temporelles et le couplage expĂ©rimentation/modĂ©lisation amĂ©liore donc notre comprĂ©hension de la dynamique des transferts sĂ©dimentaires sur le bassin versant de la Canche. Cela fournit des rĂ©sultats essentiels pour orienter les futures politiques de lutte contre lâĂ©rosion des sols
Croissance des entreprises et marchés frictionnels
Cette thĂšse sâinscrit dans les domaines de lâĂ©conomie internationale et de lâĂ©conomie du travail, et porte sur la croissance des entreprises. Les dynamiques d'entreprises jouent un rĂŽle clĂ© dans la dĂ©termination des rĂ©sultats agrĂ©gĂ©s. Il est donc essentiel de comprendre comment les entreprises se dĂ©veloppent pour comprendre la croissance Ă©conomique, l'innovation et le fonctionnement du marchĂ© du travail. Les frictions, tant sur le marchĂ© des biens que sur le marchĂ© du travail, constituent l'un des facteurs ralentissant la croissance des entreprises. D'une part, les frictions informationnelles et contractuelles entre vendeurs et acheteurs empĂȘchent les entreprises d'acquĂ©rir de nouveaux acheteurs. D'autre part, les frictions sur le marchĂ© du travail, en augmentant les coĂ»ts d'embauche et de licenciement des travailleurs, limitent la rĂ©allocation efficace des travailleurs entre les entreprises, ce qui ralentit la croissance des entreprises sur les marchĂ©s nationaux et Ă©trangers. Cette thĂšse analyse l'impact de ces deux types de frictions sur la croissance et la survie des entreprises.Le premier chapitre identifie l'impact causal du dĂ©bauchage de commerciaux provenant d'entreprises rivales sur la capacitĂ© d'une entreprise Ă dĂ©velopper son portefeuille de clients Ă l'international. Les deux derniers chapitres portent sur l'effet des frictions du marchĂ© du travail, et plus particuliĂšrement sur l'effet des politiques du marchĂ© du travail, sur la croissance et la survie des entreprises. Le deuxiĂšme chapitre dĂ©crit les biais des juges dans les tribunaux du travail et comment ils peuvent affecter les perspectives de croissance des entreprises poursuivies. Le troisiĂšme chapitre traite des accords de branche et met en avant un mĂ©canisme par lequel les grandes entreprises peuvent utiliser la nĂ©gociation sectorielle comme un dispositif anticoncurrentiel.This thesis lies in the fields of International Trade and Labor Economics and focuses on firms' growth. Firm dynamics play a key role in shaping aggregate outcomes. Understanding how firms grow and how they decline is thus crucial to understand aggregate growth, innovation, and the functioning of labor markets. One of the widely-recognized factors slowing down firms' growth is frictions, both on the product market and the labor market. On the one hand, information and contractual frictions between sellers and buyers preclude firms from reaching new buyers. On the other hand, labor market frictions, by increasing the costs to hire and dismiss workers, reduce the efficient reallocation of workers across firms, thereby slowing down firms' growth on domestic and foreign markets. This thesis analyzes the impact of those two types of frictions on firms' growth and survival.The first chapter identifies a causal impact of poaching a sales manager from other firms' labor force on a firm's ability to develop its international portfolio of clients. The two remaining chapters consider the effect of labor market frictions, and more specifically labor market policies, on firms' growth and survival. The second chapter analyses judge bias in labor courts and how it can affect the sued firms' growth prospects. The third chapter deals with sectoral agreements and highlights a mechanism by which large firms can use sectoral bargaining as an anti-competitive device
Multi-scale analysis of water erosion processes and sedimentary transfer in agricultural territory : example of the Canche river catchment (France)
LâĂ©rosion hydrique est un processus majeur de dĂ©gradation des sols dans le monde avec des consĂ©quences multiples : perte de terres agricoles, envasement des cours dâeau, coulĂ©es boueuses. En France, la rĂ©gion Hauts-de-France est la zone la plus touchĂ©e par ces pertes en terres qui peuvent dĂ©passer les 10 t ha-1 an-1. Si les processus Ă lâorigine de ces transferts sĂ©dimentaires ont Ă©tĂ© largement Ă©tudiĂ©s par la communautĂ© scientifique ces derniĂšres annĂ©es, il reste nĂ©anmoins des verrous liĂ©s aux variabilitĂ©s spatio-temporelles. De plus, lâefficacitĂ© des politiques rĂ©centes de lutte contre lâĂ©rosion nâest pas quantifiĂ©e. Cette Ă©tude propose une analyse de la variabilitĂ© spatio-temporelle des transferts sĂ©dimentaires selon plusieurs Ă©chelles (1-1000 kmÂČ), et une premiĂšre Ă©valuation de lâefficacitĂ© des politiques dâamĂ©nagement au sein dâun bassin du Nord de la France (la Canche ; 1274 kmÂČ). Une station de mesure haute-frĂ©quence, a Ă©tĂ© implĂ©mentĂ©e Ă lâexutoire dâun sous-bassin versant de la Canche (la Pommeroye ; 0,54 kmÂČ) pour quantifier les transferts hydro-sĂ©dimentaires sur deux annĂ©es hydrologiques contrastĂ©es. Selon nos rĂ©sultats, les transferts varient de 29,4 Ă 70 t km-2 an-1. 40% du flux est exportĂ© au cours de 3 Ă©pisodes Ă©rosifs majeurs (sur 48 enregistrĂ©s) et les paramĂštres forçants sont liĂ©s Ă la durĂ©e dâun Ă©pisode pluvieux et la quantitĂ© de prĂ©cipitations. Sur ce mĂȘme bassin, la prĂ©diction spatiale Ă lâĂ©chelle centimĂ©trique des transferts hydro-sĂ©dimentaires a pu ĂȘtre effectuĂ©e via le nouveau modĂšle dâĂ©rosion des sols WATERSED (BRGM) et lâefficacitĂ© dâun plan dâamĂ©nagement de lutte contre lâĂ©rosion a Ă©tĂ© quantifiĂ©e. Nos rĂ©sultats permettent de valider lâopĂ©rabilitĂ© du modĂšle sur ce territoire. Les transferts sĂ©dimentaires Ă lâĂ©chelle du parcellaire agricole peuvent atteindre les 76 t km-2 pour un Ă©vĂšnement donnĂ© et sont influencĂ©s par lâĂ©tat de surface du parcellaire agricole. Une rĂ©duction significative (jusquâĂ 84%) des transferts par les amĂ©nagements dâhydraulique douce est Ă©galement observĂ©e. A lâĂ©chelle du bassin de la Canche, lâutilisation de traceurs chimiques et spectrocolorimĂ©triques dans un modĂšle de mĂ©lange (Sed_Sat ; USGS) a permis dâĂ©valuer dâune part les contributions des affluents de la Canche et dâautre part les contributions des sols et des berges (respectivement 30-70%). Des variations spatio-temporelles significatives ont pu ĂȘtre observĂ©es et les rĂ©sultats tendent Ă montrer un potentiel impact positif des politiques rĂ©centes dâamĂ©nagement du territoire. Cette Ă©tude montre Ă©galement que de nouveaux traceurs liĂ©s Ă la signature spĂ©cifique des particules magnĂ©tiques sont particuliĂšrement prometteurs dans ce contexte pour tracer un signal dâĂ©rosion des sols. A terme, ces donnĂ©es pourraient ĂȘtre incluses dans des approches sediment fingerprinting. Lâanalyse selon plusieurs modalitĂ©s spatio-temporelles et le couplage expĂ©rimentation/modĂ©lisation amĂ©liore donc notre comprĂ©hension de la dynamique des transferts sĂ©dimentaires sur le bassin versant de la Canche. Cela fournit des rĂ©sultats essentiels pour orienter les futures politiques de lutte contre lâĂ©rosion des sols.Water erosion is a serious concern in global land degradation leading to multiple consequences: loss of arable lands, siltation of streams, mudflows. In France, the Hauts-de-France region is the most affected area, and soil loss can exceed 10 t ha-1 yr-1. Although hydro-sedimentary processes have been widely studied by the scientific community, there is still a lack of knowledge in the understanding of the spatio-temporal variabilities. Additionally, the effectiveness of recent erosion control policies so far cannot be quantified. This study proposes an analysis of the spatio-temporal variability of sedimentary transfer at different scaling (1-1000 kmÂČ), and an initial assessment of the effectiveness of management policies within a northern France catchment (the Canche river, 1274 kmÂČ). A high-frequency monitoring station was implemented at the outlet of a Canche sub-catchment (the Pommeroye, 0.54 kmÂČ) to quantify the hydro-sedimentary transfer over two contrasted hydrologic years. According to our results, sediment yield varies from 29.4 to 70 t km-2 yr-1. 40% of the flux is exported during 3 major erosive events (out of 48 recorded) and the forcing parameters are related to the duration and the amount of rainfall. In this sub-catchment, the centimeter-scale spatial prediction of the hydro-sedimentary transfer was carried out using the new soil erosion model WATERSED (BRGM) and the effectiveness of an anti-erosion management plan was quantified. Our results validate the operability of the model in this context. For a given event, sediment transfer can reach 76 t km-2 yr-1 in agricultural plots and are strongly depending on the soil surface state. A significant reduction (up to 84%) of sedimentary transfer by the anti-erosion plan was also observed. At the scale of the Canche catchment, the use of chemical and spectrocolorimetric tracers in a mixing model (Sed_Sat tool; USGS) evaluated the contributions of the Canche tributaries and sediment sources contributions (i.e. channel banks and soils; 30-70% respectively). Significant spatio-temporal variations have been observed and the results show a potential positive impact of the recent management policies. This study also shows that new tracers related to the specific signature of magnetic particles are promising in the context to trace soil erosion. For further analyses, this data could be included in sediment fingerprinting approaches. Thus, this study based on several spatio-temporal modalities and the coupling of experimentation and modelling improves our understanding of the Canche hydro-sedimentary dynamics. It provides essential results to guide the future erosion control policies
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