References of "Brouyère, Serge"
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See detailRegional transport modelling for nitrate trend assessment and forecasting in a chalk aquifer
Orban, Philippe ULg; Brouyère, Serge ULg; Batlle-Aguilar, Jordi et al

in Journal of Contaminant Hydrology (2010), 118

Regional degradation of groundwater resources by nitrate has become one of the main challenges for water managers worldwide. Regulations have been defined to reverse observed nitrate trends in groundwater ... [more ▼]

Regional degradation of groundwater resources by nitrate has become one of the main challenges for water managers worldwide. Regulations have been defined to reverse observed nitrate trends in groundwater bodies, such as the Water Framework Directive and the Groundwater Daughter Directive in the European Union. In such a context, one of the main challenges remains to develop efficient approaches for groundwater quality assessment at regional scale, including quantitative numerical modelling, as a decision support for groundwater management. A new approach combining the use of environmental tracers and the innovative ‘Hybrid Finite Element Mixing Cell’ (HFEMC) modelling technique is developed to study and forecast the groundwater quality at the regional scale, with an application to a regional chalk aquifer in the Geer basin in Belgium. Tritium data and nitrate time series are used to produce a conceptual model for regional groundwater flow and contaminant transport in the combined unsaturated and saturated zones of the chalk aquifer. This shows that the spatial distribution of the contamination in the Geer basin is essentially linked to the hydrodynamic conditions prevailing in the basin, more precisely to groundwater age and mixing and not to the spatial patterns of land use or local hydrodispersive processes. A three-dimensional regional scale groundwater flow and solute transport model is developed. It is able to reproduce the spatial patterns of tritium and nitrate and the observed nitrate trends in the chalk aquifer and it is used to predict the evolution of nitrate concentrations in the basin. The modelling application shows that the global inertia of groundwater quality is strong in the basin and trend reversal is not expected to occur before the 2015 deadline fixed by the European Water Framework Directive. The expected time required for trend reversal ranges between 5 and more than 50 years, depending on the location in the basin and the expected reduction in nitrate application. To reach a good chemical status, nitrate concentrations in the infiltrating water should be reduced as soon as possible below 50mg/l; however, even in that case, more than 50 years is needed to fully reverse upward trends. [less ▲]

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See detailHydroCube: a new entity-relationship hydrogeological data model
Wojda, Piotr; Brouyère, Serge ULg; Derouane, Johan et al

in Hydrogeology Journal (2010), 18(8), 1953-1962

Managing, handling, and accessing hydrogeological information depend mainly on the applied hydrogeological data models, which differ between institutions and across countries. Growing interest in ... [more ▼]

Managing, handling, and accessing hydrogeological information depend mainly on the applied hydrogeological data models, which differ between institutions and across countries. Growing interest in hydrogeological information diffusion, combined with a need for information availability, require the convergence of hydrogeological data models to make hydrogeological information accessible to multiple users such as universities, administrations, water suppliers, and research organisations. Furthermore, because hydrogeological studies are complex, they require a large variety of high-quality hydrogeological data with appropriate metadata in clearly designed and coherent structures. A need therefore exist to develop and implement hydrogeological data models that cover, as much as possible, the full hydrogeological domain. To respond to these requirements, a new data model, called HydroCube, has been developed for the Walloon Region in Belgium. The HydroCube model presents an innovative holistic “project-based” approach, which covers a full set of hydrogeological concepts and features, allowing for effective hydrogeological project management. This approach enables to store data about the project localisation, hydrogeological equipment, related observations and measurements. In particular, the model focuses on specialized hydrogeological field experiments, such as pumping and tracer tests. This logical data model uses entity-relationship diagrams and it has been implemented in the MS Access environment as the HydroCube database. It has been additionally enriched with a fully functional user-interface. [less ▲]

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See detailGeospatial Information in Hydrogeological Studies
Wojda, Piotr; Brouyère, Serge ULg; Dassargues, Alain ULg

in Anderson, M. G. (Ed.) Encyclopedia of Hydrological Sciences (2010)

The purpose of this article is to make a review of hydrogeological information modeling objectives, techniques, and problems, and finally to propose a solution for data integration and transfer ... [more ▼]

The purpose of this article is to make a review of hydrogeological information modeling objectives, techniques, and problems, and finally to propose a solution for data integration and transfer. Hydrogeological data and information management is crucial for efficient integrated water resources administration, protection, and exploitation. To assure an effective management of groundwater resources, a close cooperation and information exchange between different actors at different levels is necessary. The information flux must be optimized between local producers and potential users of hydrogeological data: regional and national institutions, as well as international and transboundary analysts and managers. The paper format of representation and exchange of hydrogeological information has already been replaced by different digital forms. However, an enormous diversity in applied formats and representations makes hydrogeological information extremely difficult to transfer in an automatic way. If this transition is not effective, misinterpretations of hydrogeological data may appear. The proposed solution consists in creating a domain-specific standard for the hydrogeological information exchange, using recent geomatics advances, taking into consideration appropriate ISO/TC211 and Open Geospatial Consortium (OGC) geographic information standards. Such a new electronic carrier of hydrogeological information facilitates a dialogue between interested parties using web services and inbuilt exchange mechanisms, interdisciplinary collaboration, and international harmonization of environmental sciences. [less ▲]

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See detailApplication of the Hybrid Finite Element Mixing Cell method to an abandoned coalfield in Belgium
Wildemeersch, Samuel ULg; Brouyère, Serge ULg; Orban, Philippe ULg et al

in Journal of Hydrology (2010), 392(3-4), 188-200

The Hybrid Finite Element Mixing Cell (HFEMC) method is a flexible modelling technique particularly suited to mining problems. The principle of this method is to subdivide the modelled zone into several ... [more ▼]

The Hybrid Finite Element Mixing Cell (HFEMC) method is a flexible modelling technique particularly suited to mining problems. The principle of this method is to subdivide the modelled zone into several subdomains and to select a specific equation, ranging from the simple linear reservoir equation to the groundwater flow in porous media equation, to model groundwater flow in each subdomain. The model can be run in transient conditions, which makes it a useful tool for managing mine closure post-issues such as groundwater rebound and water inrushes. The application of the HFEMC method to an abandoned underground coal mine near the city of Liege (Belgium) is presented. The case study zone has been discretized taking advantage of the flexibility of the method. Then, the model has been calibrated in transient conditions based on both hydraulic head and water discharge rate observation and an uncertainty analysis has been performed. Finally, the calibrated model has been used to run several scenarios in order to assess the impacts of possible future phenomena on the hydraulic heads and the water discharge rates. Among others, the simulation of an intense rainfall event shows a quick and strong increase in hydraulic heads in some zones coupled with an increase in associated water discharge rates. This could lead to stability problems in local hill slopes. These predictions will help managing and predicting mine water problems in this complex mining system. [less ▲]

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See detailMulti-tracer tests to evaluate the hydraulic setting of a complex aquifer system (Brévilles spring catchment, France)
Goderniaux, Pascal ULg; Brouyère, Serge ULg; Gutierrez, Alexis et al

in Hydrogeology Journal (2010)

For good management of groundwater resources, and to comply with European and national regulations, a detailed understanding of an aquifer’s hydraulic setting is required. In order to better characterize ... [more ▼]

For good management of groundwater resources, and to comply with European and national regulations, a detailed understanding of an aquifer’s hydraulic setting is required. In order to better characterize a sandy aquifer that is affected by diffuse pollution (Brévilles spring catchment, Val d'Oise, France), and to quantify the transfer time in the saturated zone, a multi-tracer test involving a new technique, the ‘Finite Volume Point Dilution Method’, has been performed in natural flow conditions. In November 2005, injections of four different tracers took place in four piezometers involving different locations and depths in the aquifer. Recovery of the tracers was observed at two different places near the aquifer outlet. A particularly long and unusual monitoring exercise (27 months) demonstrated the existence of several different velocities within the sandy layer, which seems to be linked to the decrease of hydraulic conductivity with depth. The new insight and parameter quantification brought by interpretation of these tests contribute to a better characterization of the saturated zone. The particularly long-term monitoring exercise also gives new information to understand and forecast the trend and persistence of groundwater contamination by pesticides in the catchment. [less ▲]

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See detailForeseeing nitrate concentration in groundwater: A review of available modelling approaches
Orban, Philippe ULg; Brouyère, Serge ULg

Conference (2009, December 10)

In the scientific community, increasing concerns on groundwater quality and quantity have motivated the development of numerical models for groundwater management since the 1970’s. Mathematical and ... [more ▼]

In the scientific community, increasing concerns on groundwater quality and quantity have motivated the development of numerical models for groundwater management since the 1970’s. Mathematical and numerical models are, for example, promising tools for prediction of concentration and they can be used to make the dynamic link between nitrogen manure and the resulting evolution of nitrate concentration in groundwater. However, from a practical and managerial perspective, there have been very few real attempts of developing efficient calibrated and validated transport models in particular at the scale of the groundwater body, which is the management unit of groundwater resource in the European Union. Actually two main challenges remains, (1) performing numerical tools are not really available and (2) parametrisation of such transport models at the regional scale is difficult due to the large amount of data required. Generally speaking models can be grouped in different categories ranging from black box models to physically based distributed models. The black box models such as transfer function are simple but attractive because they require relatively less data but with the drawback that modelling result are not spatially distributed while the predictive capability of these models is questionable due to the semi-analytical nature of the process descriptions. On the contrary, physically based distributed model require more data but, due to a more advanced description of ongoing processes, such models are expected to have better predictive capabilities than the black box models. Black box model and physically based distributed model approaches have all proved their utilities and have all their justifications, advantages and disadvantages regarding the development of regional scale groundwater model. A new flexible methodology (the Hybrid Finite Element Mixing Cell method) has been developed that allows combining in a single model, and in a fully integrated way, different mathematical approaches of various complexities for groundwater in complex environment. This method has been implemented in the SUFTD, a finite element groundwater flow and solute transport numerical model. Combining on the one hand the use of a spatially distributed groundwater flow and solute transport model taking advantages of this Hybrid Finite Element Mixing Cell Approach method and on the other hand spatial datasets of tritium and nitrate contents, an illustration on the problem of nitrate trend assessment and forecasting for an important groundwater resource located in the Geer groundwater body (480 km²) in the Walloon Region of Belgium will be proposed. [less ▲]

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See detailApplication of the HFEMC method to an abandoned coalfield in Belgium: From conceptualisation to scenario simulations
Wildemeersch, Samuel ULg; Brouyère, Serge ULg; Orban, Philippe ULg et al

Conference (2009, October 20)

The Hybrid Finite Element Mixing Cell (HFEMC) method is a flexible modelling technique particularly suited to mining context (Brouyère et al., 2009). The principle of this method is to subdivide the ... [more ▼]

The Hybrid Finite Element Mixing Cell (HFEMC) method is a flexible modelling technique particularly suited to mining context (Brouyère et al., 2009). The principle of this method is to subdivide the modelled zone into several subdomains and to select a specific equation, ranging from the simple linear reservoir equation to the groundwater flow in porous media equation, to model groundwater flow in each subdomain. The model can be run in transient conditions, which makes it a useful tool for managing mine closure post-issues such as groundwater rebound and water inrushes. An application of the HFEMC method to an abandoned underground coal mine near the city of Liège (Belgium) is presented. The case study zone has been discretized taking advantage of the flexibility of the method. Then, the model has been calibrated in both steady-state and transient flow regimes based on hydraulic head and water discharge rate observations. Finally, the calibrated model has been used to run several scenarios in order to assess the impacts of possible future phenomena on the hydraulic heads and the water discharge rates. Among others, the simulation of a strong rainfall event shows a quick and strong increase in hydraulic heads in some exploited zones coupled with a strong increase in associated water discharge rates. This could lead to stability problems in the hill slopes near the exploited zones. This kind of predictions can greatly help managing and predicting mine water problems in this particularly complex mining system. [less ▲]

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See detailDélivrable 15 - Rapport d'avancement Convention A
Dollé, Fabien ULg; Jamin, Pierre ULg; Gesels, Julie ULg et al

Report (2009)

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See detailUsing Electrical Resistivity Tomography and Self-potential Methods for Wells Implementations in Fractured Limestones
Robert, Tanguy ULg; Dassargues, Alain ULg; Brouyère, Serge ULg et al

in EarthDoc - Near Surface 2009 – 15th European Meeting of Environmental and Engineering Geophysics (2009, September 09)

Electrical resistivity tomography (ERT) and self-potential (SP) investigations were conducted in fractured limestones in Belgium. The aim of this study was to find suitable positions for high yield water ... [more ▼]

Electrical resistivity tomography (ERT) and self-potential (SP) investigations were conducted in fractured limestones in Belgium. The aim of this study was to find suitable positions for high yield water wells. Large ERT profiles (640 meters) allowed us to image the resistivity distribution of the first 60 meters of the subsurface and to detect and characterize (in terms of direction, width and depth) fractured zones expected to be less resistive. Data errors, DOI indexes and sensitivity models were analysed in order to calculate the depth of investigation of ERT and to avoid the misinterpretation of the resulting images. Self-potential measurements were performed along electrical profiles to narrow the possible locations given by the electrical images. Some negative anomalies possibly related to preferential flow were detected. ‘Ground truth’ geological data as well as pumping tests information gave us a way to assess the contribution of geophysics to a drilling programme. Wells implemented in low resistivity zones associated with SP anomalies have very high yields. Inversely, wells drilled in resistive zones or outside SP anomalies have poorer capacities. An apparent coupling coefficient between SP signals and differences in hydraulic heads was also estimated in order to image the water table. [less ▲]

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See detailHow can large scale integrated surface - subsurface hydrological model be used to evaluate long term climate change impact on groundwater reserves
Goderniaux, Pascal ULg; Brouyère, Serge ULg; Fowler, Hayley J. et al

in Proceeding of the 7th international conference on calibration and reliability in groundwater modeling (2009, September)

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See detailProspection géophysique de la nappe alluviale dans la région de Nasso, Bodo – Dioulasso (Burkina Faso)
Beaujean, Jean ULg; Nguyen, Frédéric ULg; Sauret, Elie ULg et al

Report (2009)

Afin d’appuyer la gestion et la protection des ressources en eaux souterraines au Burkina Faso, dans la région de Bobo-Dioulasso, une mission géophysique relative à la caractérisation du site de la plaine ... [more ▼]

Afin d’appuyer la gestion et la protection des ressources en eaux souterraines au Burkina Faso, dans la région de Bobo-Dioulasso, une mission géophysique relative à la caractérisation du site de la plaine alluviale dans la localité de Nasso a été effectuée. Plusieurs méthodes géophysiques ont été employées afin de déterminer l’hétérogénéité des terrains superficiels, l’épaisseur de la nappe alluviale, ainsi que la profondeur du bedrock. Les trois méthodes déployées pour atteindre ces objectifs sont la tomographie électrique, le bruit de fond H/V, et le radar géologique. Ce dernier n’a pas donné de résultats satisfaisant tandis que les deux autres méthodes se sont montrées concluantes pour déterminer la profondeur du bedrock et détecter des hétérogénéités dans les terrains superficiels et profonds. [less ▲]

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See detailReframing groundwater vulnerability assessment for a better understanding between decision makers and hydrogeologists
Dassargues, Alain ULg; Popescu, Ileana Cristina; Beaujean, Jean ULg et al

in Liebscher, Hans-Jurgen; Clarke, Robin; Rodda, John (Eds.) et al The Role of Hydrology in Water Resources Management (2009, June)

Management of water resource systems includes adequate decisions about groundwater resource protection. Groundwater vulnerability maps can greatly help for these decisions. In the vulnerability assessment ... [more ▼]

Management of water resource systems includes adequate decisions about groundwater resource protection. Groundwater vulnerability maps can greatly help for these decisions. In the vulnerability assessment, physical attributes are often mixed with conventional priorities implicitly embedded in the applied methods. Results from one or another method can consequently be very dissimilar and decision makers are losing confidence in these tools. A methodology is proposed to reframe the groundwater vulnerability assessment in a Pressure-State-Impact causal chain that is familiar to decision makers. The physically-based analysis is clearly separated from the agreement aspects induced by local societal, environmental or political priorities. An example is given and perspectives of generalisation are evoked. [less ▲]

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See detailRapport de synthèse des travaux et résultats obtenus dans le cadre du projet FP6 AquaTerra et relatifs à l’étude hydrogéologique et la modélisation numérique écoulement – transport pour le site de l’ancienne cokerie de Flémalle
Brouyère, Serge ULg; Batlle-Aguilar, Jordi

Report (2009)

In the framework of Workpackage BASIN R3 Meuse, the Hydrology Group of the University of Liège (Belgium) has worked on two case studies for end-users in the Walloon region of Belgium. The first case study ... [more ▼]

In the framework of Workpackage BASIN R3 Meuse, the Hydrology Group of the University of Liège (Belgium) has worked on two case studies for end-users in the Walloon region of Belgium. The first case study deals with the problem of nitrate contamination of the Hesbaye chalk aquifer located in the Geer basin, in the region of Liège. This research is of major interest for the Groundwater Division of the Administration for Agriculture, Environment and Natural Resources of the Walloon region as a support to reporting in the scope of the EU Water Directive. The second case study deals with a problem of soil and groundwater pollution of the alluvial aquifer of the river Meuse in the brownfield of a former coke factory in Flémalle, near the city of Liège. This research is of major interest as a support to decision making in terms of site cleanup and rehabilitation as managed by SPAQuE, the public society in charge of managing contaminated sites in the Walloon region of Belgium. This deliverable is a compilation of specific final reports written in French that have been delivered to these end-users (DGARNE Groundwater Division and SPAQuE), as a support to decision-making with respect to the environmental issues they have to manage. [less ▲]

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See detailGround water flow simulation in mining works: Application of the Hybrid Finite Element Mixing Cell method
Wildemeersch, Samuel ULg; Orban, Philippe ULg; Brouyère, Serge ULg et al

Conference (2009, April 22)

Hydrogeological models can greatly help simulating groundwater flow in the particular context of mining works. However, classical modeling techniques are not so suited in this context because the medium ... [more ▼]

Hydrogeological models can greatly help simulating groundwater flow in the particular context of mining works. However, classical modeling techniques are not so suited in this context because the medium is strongly disturbed by shafts and networks of galleries. Consequently, specific modeling techniques have been developed. Box model techniques require only few parameters but they calculate only mean water levels in exploited zones and do not consider interactions between exploited and unexploited zones. Conversely, physically-based and spatially-distributed techniques represent explicitly both exploited and unexploited zones and take into account interactions between them but they require a lot of parameters sometimes difficult to estimate. The Hybrid Finite Element Mixing Cell (HFEMC) method is a new modeling technique constituting a compromise between simple and complex techniques used in mining context. The principle of this method is to fully couple a representation of exploited zones by a group of mixing cells possibly interconnected by pipes and a representation of unexploited zones by classical finite elements. Interactions between mixing cells and finite elements of the mesh are taken into account through 3rd type (Fourier) internal boundary conditions. With this method, exploited zones are characterized by mean water levels while spatially-distributed hydraulic heads are calculated for the entire adjacent and overlaying unexploited zones. Additionally, thanks to the coupling between mixing cells and finite elements, water exchanges between exploited and unexploited zones are explicitly taken into account. The HFEMC method allows also simulating groundwater rebound following mine closure and associated phenomena such as water inrushes. Concepts and equations of the HFEMC method are presented and illustrated using test cases. First results of an application on an abandoned coalfield in the region of Liege (Belgium) are also proposed. [less ▲]

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