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Papers by Vincent Mardhel

Research paper thumbnail of Atlas interactif des pêcheries palangrières opérant dans les ZEE françaises de l'océan Indien

Research paper thumbnail of La contribution des eaux souterraines aux inondations - Modélisation des hautes eaux de la Somme

Extensive flooding of the Somme river basin in spring 2001 revealed the fundamental role of groun... more Extensive flooding of the Somme river basin in spring 2001 revealed the fundamental role of groundwater in the appearance and intensity of some floods. Forecasting models developed must now enable to draw attention to periods of risk early enough for this type of flood. Résumé Français : Les importantes inondations de la Somme au printemps 2001 ont révélé le rôle fondamental des eaux souterraines dans l’apparition et l’intensité de certaines crues. Les modèles de prévision développés doivent maintenant permettre d’annoncer les périodes à risque suffisamment tôt pour ce type de crue.

Research paper thumbnail of La contribution des eaux souterraines aux crues exceptionnelles de la Somme en 2001 Observations, hypothèses, modélisation

La Houille Blanche, 2003

ABSTRACT The 2000-2001 high water levels in the Somme catchment highlited the possible contributi... more ABSTRACT The 2000-2001 high water levels in the Somme catchment highlited the possible contribution of groundwaters to surficial floods, with considerations which could be extrapolated to a great number of sedimentary geological provinces displaying a plateau landscape, those mostly located in the northern half territory of France. Successively an interministerial Commission, the Regional Directorate for Environment of Picardie, and the General Council of Somme asked Brgm to analyse the underground geo-structures and seepage as part of the fluxes and exchanges which took place during 2000-2001 winter, and thus to create a forecasting tool based on mathematical simulations. A flood is integrating several components, ranking from the rainfall to the river flux, the relative weight of which being affected by the morphology, the surficial hydrology, land uses, as well as seasonal conditions such as frozen soils. One peculiar component is the groundwater outlet which may be fairly significant from a chalk body, such as the general substratum of the Somme watershed. The hydrodynamic rules which apply to seepage, allowed an extension of modelling techniques, commonly used in groundwater resources management, to the seasonal events computation in the Somme region, in order to partly provide an explanation of the groundwater contribution within the water balance. Several models were created, lumped up and deteministic ones. From july 2001 on, a complete rebulting of the geological scheme was performed and data series computed. The first deterministic model was available in december 2001. Both models showed that the successive sub-catchement contributions to the river flow were increasing from up- to downstream. Seasonaly, the total groundwater contribution, close to 100% in low water periods, remains at a significant level, even at flood time : not less than 80%. The isotopie facies gave a confirmation of the relatively high contribution of groundwater into the river flow. The forecasting tool built up in 2001 helps computing the variations of flow at the city of Abbeville. It is operated every fortnight in winter and spring time (from november to may) from 2002 on. The deterministic model is operated once a year, a posteriori, to bring up the local relative contributions of groundwater into stream flow, over the last one year period.

Research paper thumbnail of A GIS-based Vehicle Mobility Estimator for Operational Contexts

Transactions in GIS, 2013

A vehicle mobility estimator has been developed to produce decision aid maps for projecting civil... more A vehicle mobility estimator has been developed to produce decision aid maps for projecting civil or military forces on operational theatres. Based on the exploitation of classical geographical sources (e.g. digital elevation models, optical images, and vector databases) and thematic sources (e.g. climate, meteorological, pedological and land cover databases), the system computes speed maps for different kinds of vehicles moving both on-road and off-road. Such computations are realized through a ground-vehicle interaction module that estimates the vehicle performance from experimental results, numerical simulations and empirical relationships. The system's architecture is built using a GIS interface that manages the data, the computation and the presentation layers. An operational version of this tool has been tested and validated on several operational theatres in France and in northern Africa. The results show good agreement between the predicted mobility performance of various vehicles and those observed on the field. A case study is presented to illustrate the mobility maps and demonstrate their relevance in the decision-making chain depending on different climate contexts. A short application to itinerary optimization is presented as a promising future application.

Research paper thumbnail of Vers un modèle hydrologique simplifié pour les études géomécaniques spatialisées

La Houille Blanche, 2010

Estimating soils geomechanical behavior interest numerous applications dealing with natural hazar... more Estimating soils geomechanical behavior interest numerous applications dealing with natural hazards, landscape management or terrestrial vehicles mobility. These applications need most of the time high time reactivity in producing decision-making maps, a strong input data availability and a spatial resolution in the order of decametric scale. This work presents an simplified hydrologic model allowing estimation of soil moisture from a generic dataset. This model is based on qualitative indexes related to runoff and infiltration processes that are convolved with climatic data extracted from a global database. The link between the resulting moisture map and the soil geomechanical behavior can be established from field observations or laboratory measurements. This model is applied to two different cases history and is discussed in term of positive results and limitations.

Research paper thumbnail of Atlas interactif des pêcheries palangrières opérant dans les ZEE françaises de l'océan Indien

Research paper thumbnail of La contribution des eaux souterraines aux inondations - Modélisation des hautes eaux de la Somme

Extensive flooding of the Somme river basin in spring 2001 revealed the fundamental role of groun... more Extensive flooding of the Somme river basin in spring 2001 revealed the fundamental role of groundwater in the appearance and intensity of some floods. Forecasting models developed must now enable to draw attention to periods of risk early enough for this type of flood. Résumé Français : Les importantes inondations de la Somme au printemps 2001 ont révélé le rôle fondamental des eaux souterraines dans l’apparition et l’intensité de certaines crues. Les modèles de prévision développés doivent maintenant permettre d’annoncer les périodes à risque suffisamment tôt pour ce type de crue.

Research paper thumbnail of La contribution des eaux souterraines aux crues exceptionnelles de la Somme en 2001 Observations, hypothèses, modélisation

La Houille Blanche, 2003

ABSTRACT The 2000-2001 high water levels in the Somme catchment highlited the possible contributi... more ABSTRACT The 2000-2001 high water levels in the Somme catchment highlited the possible contribution of groundwaters to surficial floods, with considerations which could be extrapolated to a great number of sedimentary geological provinces displaying a plateau landscape, those mostly located in the northern half territory of France. Successively an interministerial Commission, the Regional Directorate for Environment of Picardie, and the General Council of Somme asked Brgm to analyse the underground geo-structures and seepage as part of the fluxes and exchanges which took place during 2000-2001 winter, and thus to create a forecasting tool based on mathematical simulations. A flood is integrating several components, ranking from the rainfall to the river flux, the relative weight of which being affected by the morphology, the surficial hydrology, land uses, as well as seasonal conditions such as frozen soils. One peculiar component is the groundwater outlet which may be fairly significant from a chalk body, such as the general substratum of the Somme watershed. The hydrodynamic rules which apply to seepage, allowed an extension of modelling techniques, commonly used in groundwater resources management, to the seasonal events computation in the Somme region, in order to partly provide an explanation of the groundwater contribution within the water balance. Several models were created, lumped up and deteministic ones. From july 2001 on, a complete rebulting of the geological scheme was performed and data series computed. The first deterministic model was available in december 2001. Both models showed that the successive sub-catchement contributions to the river flow were increasing from up- to downstream. Seasonaly, the total groundwater contribution, close to 100% in low water periods, remains at a significant level, even at flood time : not less than 80%. The isotopie facies gave a confirmation of the relatively high contribution of groundwater into the river flow. The forecasting tool built up in 2001 helps computing the variations of flow at the city of Abbeville. It is operated every fortnight in winter and spring time (from november to may) from 2002 on. The deterministic model is operated once a year, a posteriori, to bring up the local relative contributions of groundwater into stream flow, over the last one year period.

Research paper thumbnail of A GIS-based Vehicle Mobility Estimator for Operational Contexts

Transactions in GIS, 2013

A vehicle mobility estimator has been developed to produce decision aid maps for projecting civil... more A vehicle mobility estimator has been developed to produce decision aid maps for projecting civil or military forces on operational theatres. Based on the exploitation of classical geographical sources (e.g. digital elevation models, optical images, and vector databases) and thematic sources (e.g. climate, meteorological, pedological and land cover databases), the system computes speed maps for different kinds of vehicles moving both on-road and off-road. Such computations are realized through a ground-vehicle interaction module that estimates the vehicle performance from experimental results, numerical simulations and empirical relationships. The system's architecture is built using a GIS interface that manages the data, the computation and the presentation layers. An operational version of this tool has been tested and validated on several operational theatres in France and in northern Africa. The results show good agreement between the predicted mobility performance of various vehicles and those observed on the field. A case study is presented to illustrate the mobility maps and demonstrate their relevance in the decision-making chain depending on different climate contexts. A short application to itinerary optimization is presented as a promising future application.

Research paper thumbnail of Vers un modèle hydrologique simplifié pour les études géomécaniques spatialisées

La Houille Blanche, 2010

Estimating soils geomechanical behavior interest numerous applications dealing with natural hazar... more Estimating soils geomechanical behavior interest numerous applications dealing with natural hazards, landscape management or terrestrial vehicles mobility. These applications need most of the time high time reactivity in producing decision-making maps, a strong input data availability and a spatial resolution in the order of decametric scale. This work presents an simplified hydrologic model allowing estimation of soil moisture from a generic dataset. This model is based on qualitative indexes related to runoff and infiltration processes that are convolved with climatic data extracted from a global database. The link between the resulting moisture map and the soil geomechanical behavior can be established from field observations or laboratory measurements. This model is applied to two different cases history and is discussed in term of positive results and limitations.