A methodology is developed for proposing a groundwater vulnerability assessment in a Pressure-Sta... more A methodology is developed for proposing a groundwater vulnerability assessment in a Pressure-State-Impact causal chain that is familiar to decision makers. The ‘Driver Pressure State Impact Response ’ (DPSIR) framework, for describing interactions between society and the environment, defines a chain of Drivers that exert Pressures on the State of a given resource, such as groundwater, which then generates an Impact that will require an appropriate Response (Kristensen, 2004). The method is here based on the calculation of sensitivity coefficients for a user-defined groundwater state for which several physically-based indicators are proposed. These sensitivity coefficients reflect the easiness with which the groundwater state transmits pressures into impacts. They are grouped into a vulnerability matrix of pressures and impacts that quantify vulnerability for every combination of causal links identified in the DPSIR chain. For that reason, the sensitivity coefficients are converted ...
Numerous groundwater vulnerability and risk mapping techniques have been developed, taking into c... more Numerous groundwater vulnerability and risk mapping techniques have been developed, taking into consideration a variable number of factors. The most common techniques are based on calculation of an index expressing the protective effect of underground formations overlying the groundwater resource. The limitation of most of these methods is related to their use of a qualitative definition of groundwater vulnerability, as opposed to a definition based on a quantitative description of contaminant migration. A physically-based point of view and definition of the vulnerability is proposed and based on three factors describing a pollution event, which are the contaminant transfer time from the hazard location to the target, the contamination duration at the target, and the level of contaminant concentration reached at the target. This concept allows a clear distinction between conventional aspects and physically-based results in the building of a final vulnerability indicator. This method...
paramètres chimiques présents naturellement dans les masses d'eau souterraine captives du Socle e... more paramètres chimiques présents naturellement dans les masses d'eau souterraine captives du Socle et du Crétacé (BR01) et du Landénien (BR03) en Région de Bruxelles-Capitale » Good quantitative and chemical status for all groundwater bodies Threshold values Natural background levels / Baseline Concentrations JME2019 Hydrogéologie, Géologie, Géothermie en RBC : nouveaux outils, données et connaissances Context of the study 3 Rainfall composition Evapotranspiration-by vegetation Chemical composition and mineralogy of the soil Lithology of the underground Physico-chemical conditions Residence time Groundwater flow conditions Mixing between different waters [Human activities!] Physical & Chemical disequilibrium reactions and evolution of groundwater composition 3 What controls the chemistry of groundwater?
A new mathematical approach is proposed to model the injection of a tracer in a well for field tr... more A new mathematical approach is proposed to model the injection of a tracer in a well for field tracer tests, It is based on the water and tracer mass budget integrated over the injection well, for the different injection steps (tracer injection, water flush and tracer behaviour after the injection). This physical approach deals with well-bore mixing and dilution effects, local distortion of the flow field around the injection well, back-diffusion of the tracer in the injection well after the injection, and tracer capture in the well bore. A numerical solution (finite differences over time) is proposed and implemented in a three-dimensional finite element flow and transport simulator (SUFT3D). A radially converging tracer test is computed to illustrate the adequacy and usefulness of this new mathematical concept to model field results.
The development of transboundary groundwater resources has generated, and will continue to genera... more The development of transboundary groundwater resources has generated, and will continue to generate acrimony among states, nations and provinces. But groundwater resources can also promote peace and accommodation, as jurisdictions and decision-makers, who share a common groundwater resource, realize that cooperation is the only way to ensure resource protection and sustainability. The Somes-Szamos aquifer, which extends on both sides of the Romanian-Hungarian border, supplies drinking water to a population of about 395000 inhabitants in Romania and 50000 inhabitants in Hungary. The research project named SQUASH (for Somes/Szamos Quantitative/Qualitative Study of the Hydrogeology) carried out between 2000-2004 by a group of teams formed by Belgium, Romanian and Hungarian partners, in the scope and supported by the NATO Science for Peace programme, was intended to develop common tools and guidelines for local end-users (water supply companies and regulatory authorities from Romania and Hungary) in order to be able to manage the groundwater quantity and quality. The project focused on improving the previous understanding of the groundwater conditions
Multi-tracer tests were carried out close to a pumping well in fluvial deposits located in the Me... more Multi-tracer tests were carried out close to a pumping well in fluvial deposits located in the Meuse valley near Liege in Belgium. Detailed investigations with different tracers and injection procedures have provided a very complete data set of measured breakthrough curves at the pumping well. Influence of the tracer nature and of tracer injection conditions on the measured concentrations can be observed. Heterogeneity of the porous medium gravels intersected by sandy and silty lenses was previously investigated using geo-electrical resistivity measurements. In groundwater flow and transport simulations, it is represented deterministically by the choice of various flow and transport parameters in the modeled zone. After calibration on the multiple measured breakthrough curves, the comparison with analytical solutions assuming advection-dispersion in homogeneous radial conditions is particularly interesting. Conclusions are drawn in three directions, all of them having a strong influ...
Background Measurement of the rate of contaminated groundwater discharge to the receiving surface... more Background Measurement of the rate of contaminated groundwater discharge to the receiving surface water is a more direct and often less conservative approach than models that omit attenuation processes and mixing at the groundwater-surface water interface. Not undertaking such measurements can lead to conservative and potentially costly decisions such as inappropriate remedial actions. The groundwater-surface water interface, in particular in marine environments, is a dynamic zone with processes such as tides, wave dynamics, and swash infiltration all contributing to the mixing. These interfaces can also significantly attenuate contaminants given the presence of strong redox gradients.
The experimental study of the behavior of the shallow aquifer under irrigation was conducted in t... more The experimental study of the behavior of the shallow aquifer under irrigation was conducted in two rice fields. The experimental set-up consists of: • pressure probes to monitor the surface water level in flooded rice plot, • TDR probes for measuring soil moisture, • measuring probes of the groundwater level and the EC of the groundwater, • network of piezometers for monitoring the water table, • Suction cup for monitoring the soil solution
An important challenge faced by environmental practitioners is the estimation of the impact of co... more An important challenge faced by environmental practitioners is the estimation of the impact of contamination that is transported from the source of contamination to soil and groundwater at industrial sites. Specifically, quantification of contaminant flux in the vadose zone is challenging due partly to the heterogeneity of the complex porous medium and the preferential flow. Contaminant flux estimations are essential to better establish risk assessment of soil and groundwater as well as to support the selection of remedial measures. Several methods have been developed for contaminant flux estimations in the vadose zone. These methodologies are either based on modelling, on experimental approaches, or on the combination of both, and have been developed principally in the context of agricultural purposes. However, the applicability of such techniques is questioned when it comes to their application to industrial sites, due to differences in depth of investigation, soil origin, contami...
A methodology is developed for proposing a groundwater vulnerability assessment in a Pressure-Sta... more A methodology is developed for proposing a groundwater vulnerability assessment in a Pressure-State-Impact causal chain that is familiar to decision makers. The ‘Driver Pressure State Impact Response ’ (DPSIR) framework, for describing interactions between society and the environment, defines a chain of Drivers that exert Pressures on the State of a given resource, such as groundwater, which then generates an Impact that will require an appropriate Response (Kristensen, 2004). The method is here based on the calculation of sensitivity coefficients for a user-defined groundwater state for which several physically-based indicators are proposed. These sensitivity coefficients reflect the easiness with which the groundwater state transmits pressures into impacts. They are grouped into a vulnerability matrix of pressures and impacts that quantify vulnerability for every combination of causal links identified in the DPSIR chain. For that reason, the sensitivity coefficients are converted ...
Numerous groundwater vulnerability and risk mapping techniques have been developed, taking into c... more Numerous groundwater vulnerability and risk mapping techniques have been developed, taking into consideration a variable number of factors. The most common techniques are based on calculation of an index expressing the protective effect of underground formations overlying the groundwater resource. The limitation of most of these methods is related to their use of a qualitative definition of groundwater vulnerability, as opposed to a definition based on a quantitative description of contaminant migration. A physically-based point of view and definition of the vulnerability is proposed and based on three factors describing a pollution event, which are the contaminant transfer time from the hazard location to the target, the contamination duration at the target, and the level of contaminant concentration reached at the target. This concept allows a clear distinction between conventional aspects and physically-based results in the building of a final vulnerability indicator. This method...
paramètres chimiques présents naturellement dans les masses d'eau souterraine captives du Socle e... more paramètres chimiques présents naturellement dans les masses d'eau souterraine captives du Socle et du Crétacé (BR01) et du Landénien (BR03) en Région de Bruxelles-Capitale » Good quantitative and chemical status for all groundwater bodies Threshold values Natural background levels / Baseline Concentrations JME2019 Hydrogéologie, Géologie, Géothermie en RBC : nouveaux outils, données et connaissances Context of the study 3 Rainfall composition Evapotranspiration-by vegetation Chemical composition and mineralogy of the soil Lithology of the underground Physico-chemical conditions Residence time Groundwater flow conditions Mixing between different waters [Human activities!] Physical & Chemical disequilibrium reactions and evolution of groundwater composition 3 What controls the chemistry of groundwater?
A new mathematical approach is proposed to model the injection of a tracer in a well for field tr... more A new mathematical approach is proposed to model the injection of a tracer in a well for field tracer tests, It is based on the water and tracer mass budget integrated over the injection well, for the different injection steps (tracer injection, water flush and tracer behaviour after the injection). This physical approach deals with well-bore mixing and dilution effects, local distortion of the flow field around the injection well, back-diffusion of the tracer in the injection well after the injection, and tracer capture in the well bore. A numerical solution (finite differences over time) is proposed and implemented in a three-dimensional finite element flow and transport simulator (SUFT3D). A radially converging tracer test is computed to illustrate the adequacy and usefulness of this new mathematical concept to model field results.
The development of transboundary groundwater resources has generated, and will continue to genera... more The development of transboundary groundwater resources has generated, and will continue to generate acrimony among states, nations and provinces. But groundwater resources can also promote peace and accommodation, as jurisdictions and decision-makers, who share a common groundwater resource, realize that cooperation is the only way to ensure resource protection and sustainability. The Somes-Szamos aquifer, which extends on both sides of the Romanian-Hungarian border, supplies drinking water to a population of about 395000 inhabitants in Romania and 50000 inhabitants in Hungary. The research project named SQUASH (for Somes/Szamos Quantitative/Qualitative Study of the Hydrogeology) carried out between 2000-2004 by a group of teams formed by Belgium, Romanian and Hungarian partners, in the scope and supported by the NATO Science for Peace programme, was intended to develop common tools and guidelines for local end-users (water supply companies and regulatory authorities from Romania and Hungary) in order to be able to manage the groundwater quantity and quality. The project focused on improving the previous understanding of the groundwater conditions
Multi-tracer tests were carried out close to a pumping well in fluvial deposits located in the Me... more Multi-tracer tests were carried out close to a pumping well in fluvial deposits located in the Meuse valley near Liege in Belgium. Detailed investigations with different tracers and injection procedures have provided a very complete data set of measured breakthrough curves at the pumping well. Influence of the tracer nature and of tracer injection conditions on the measured concentrations can be observed. Heterogeneity of the porous medium gravels intersected by sandy and silty lenses was previously investigated using geo-electrical resistivity measurements. In groundwater flow and transport simulations, it is represented deterministically by the choice of various flow and transport parameters in the modeled zone. After calibration on the multiple measured breakthrough curves, the comparison with analytical solutions assuming advection-dispersion in homogeneous radial conditions is particularly interesting. Conclusions are drawn in three directions, all of them having a strong influ...
Background Measurement of the rate of contaminated groundwater discharge to the receiving surface... more Background Measurement of the rate of contaminated groundwater discharge to the receiving surface water is a more direct and often less conservative approach than models that omit attenuation processes and mixing at the groundwater-surface water interface. Not undertaking such measurements can lead to conservative and potentially costly decisions such as inappropriate remedial actions. The groundwater-surface water interface, in particular in marine environments, is a dynamic zone with processes such as tides, wave dynamics, and swash infiltration all contributing to the mixing. These interfaces can also significantly attenuate contaminants given the presence of strong redox gradients.
The experimental study of the behavior of the shallow aquifer under irrigation was conducted in t... more The experimental study of the behavior of the shallow aquifer under irrigation was conducted in two rice fields. The experimental set-up consists of: • pressure probes to monitor the surface water level in flooded rice plot, • TDR probes for measuring soil moisture, • measuring probes of the groundwater level and the EC of the groundwater, • network of piezometers for monitoring the water table, • Suction cup for monitoring the soil solution
An important challenge faced by environmental practitioners is the estimation of the impact of co... more An important challenge faced by environmental practitioners is the estimation of the impact of contamination that is transported from the source of contamination to soil and groundwater at industrial sites. Specifically, quantification of contaminant flux in the vadose zone is challenging due partly to the heterogeneity of the complex porous medium and the preferential flow. Contaminant flux estimations are essential to better establish risk assessment of soil and groundwater as well as to support the selection of remedial measures. Several methods have been developed for contaminant flux estimations in the vadose zone. These methodologies are either based on modelling, on experimental approaches, or on the combination of both, and have been developed principally in the context of agricultural purposes. However, the applicability of such techniques is questioned when it comes to their application to industrial sites, due to differences in depth of investigation, soil origin, contami...
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