References of "Dassargues, Alain"
     in
Bookmark and Share    
See detailCarte hydrogéologique de Wallonie, Hamoir-Ferrières, 49/5-6
Ruthy, Ingrid ULg; Dassargues, Alain ULg

Cartographic material (2005)

Detailed reference viewed: 8 (0 ULg)
Full Text
See detailSchéma directeur intégré pour la préservation de la qualité de l’eau et la valorisation écologique des lacs de l’Eau d’Heure dans le cadre du développement touristique et économique du site
Everbecq, Etienne ULg; Deliège, Jean-François ULg; Bourouag, Mohamed ULg et al

Report (2005)

Schéma directeur intégré pour la préservation de la qualité de l’eau et la valorisation écologique des lacs de l’Eau d’Heure dans le cadre du développement touristique et économique du site Les barrages ... [more ▼]

Schéma directeur intégré pour la préservation de la qualité de l’eau et la valorisation écologique des lacs de l’Eau d’Heure dans le cadre du développement touristique et économique du site Les barrages de l'Eau d'Heure (cinq plans d’eau, dont deux principaux liés à la construction des deux grands barrages de la Plate Taille et de l'Eau d'Heure) ont comme but principal de soutenir le débit d’étiage de la Sambre, tout en contribuant à réduire les effets des pollutions urbaines et industrielles résiduelles et à soutenir le débit du canal Charleroi-Bruxelles. Outre ces fonctions, le complexe "Eau d'Heure" représente un attrait touristique indéniable. Des infrastructures touristiques importantes ont été construites, elles constituent un risque pour la qualité de l'eau et de l'environnement. Le niveau de qualité de l'eau est préoccupant pour certains lacs ; aussi, dans l'esprit du « Phasing out » de l'objectif 1, il était urgent d'entreprendre des actions au niveau environnemental pour revaloriser le site des lacs de d'Eau d'Heure, aussi bien au niveau du potentiel touristique que de la qualité environnementale en tant que telle. Le "Schéma directeur intégré pour la préservation de la qualité de l'eau et la valorisation écologique des lacs de l'Eau d'Heure dans le cadre du développement touristique et économique du site" est un projet financé par la Région wallonne et par le fonds européen FEDER. Le programme s’est étalé sur trois ans de 2002 à 2004. Dans une première phase (2 ans), un bilan complet de la qualité des eaux a été dressé : niveau d’eutrophisation, bilan des apports d’eau par le bassin versant (ruissellement, écoulements souterrains ou nappes aquifères), bilan des apports de matières organiques et de nutriments en fonction des activités humaines (notamment agricoles). Le fonctionnement écologique de tout le système a aussi fait l’objet d’études détaillées. Le lien entre tous ces éléments, assuré par une modélisation mathématique, a permis de dégager des actions susceptibles de contrôler l’eutrophisation afin de restaurer les milieux naturels et les biocénoses. Durant la deuxième phase, des recommandations de gestion ont été formulées. Le projet était construit sur un partenariat entre IGRETEC et deux institutions universitaires (FUNDP-URBO/GIREA et ULg-Centre Environnement), en relation avec les communes, les administrations wallonnes (MET, DGRNE, DGATLP, Commissariat au Tourisme …) ainsi qu’avec les gestionnaires (MET, AGLEH). Une "Plaquette" est annexée à cette référence, cf. section 'Adjuvant". Elle a été réalisée par le GIREA (Verniers, G. et Leroy, P.) et le URBO (Sarmento, H.) de la FUNDP, et décrit en synthèse les tâches réalisées au cours de cette étude par l'ensemble des partenaires scientifiques. [less ▲]

Detailed reference viewed: 51 (7 ULg)
Full Text
See detailCarte hydrogéologique du plateau d’Oulmès (Maroc)
Elbatloussi, Dounia; Cheddadi, Meriem; Dadi, Sliman et al

Report (2005)

Detailed reference viewed: 409 (4 ULg)
Full Text
See detailL’eau dans tous ses état : enjeux et difficultés de la gestion des eaux souterraines
Dassargues, Alain ULg

Scientific conference (2005, January 20)

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of injection conditions on field tracer experiments
Brouyère, Serge ULg; Carabin, Guy; Dassargues, Alain ULg

in Ground Water (2005), 43(3), 389-400

Calibration of ground water transport models is often performed using results of field tracer experiments. However, little attention is usually paid to the influence, on resulting breakthrough curves, of ... [more ▼]

Calibration of ground water transport models is often performed using results of field tracer experiments. However, little attention is usually paid to the influence, on resulting breakthrough curves, of injection conditions and well-aquifer interactions, more particularly of the influence of the possible trapping of the tracer in the injection wellbore. Recently, a new mathematical and numerical approach has been developed to model injection conditions and well-aquifer interactions in a very accurate way. Using an analytical solution derived from this model, a detailed analysis is made of the evolution of the tracer input function in the aquifer. By varying injection conditions from one simulation to another, synthetic breakthrough curves are generated with the SUFT3D ground water flow and transport finite-element simulator. These tests show clearly that the shape of the breakthrough curves can be dramatically affected by injection conditions. Using generated breakthrough curves as "actual" field results, a calibration of hydrodispersive parameters is performed, neglecting the influence of injection conditions. This shows that neglecting the influence of actual injection conditions can lead to (1) errors on fitted parameters and (2) misleading identification of the active transport processes. Conclusions and guidelines are drawn in terms of proposed methodologies for better controlling the tracer injection in the field, in order to minimize risk of misinterpretation of results. [less ▲]

Detailed reference viewed: 39 (12 ULg)
Full Text
See detailIntegrated modelling of the hydrological cycle in relation to global climate change
Deliège, Jean-François ULg; Bourouag, Mohamed ULg; Dzisiak, J. P. et al

Report (2005)

The main objectives of the project “INTEGRATED MODELLING OF THE HYDROLOGICAL CYCLE IN RELATION TO GLOBAL CLIMATE CHANGE” (CG/DD/08), are : - to gain knowledge in the understanding of the hydrological ... [more ▼]

The main objectives of the project “INTEGRATED MODELLING OF THE HYDROLOGICAL CYCLE IN RELATION TO GLOBAL CLIMATE CHANGE” (CG/DD/08), are : - to gain knowledge in the understanding of the hydrological system at different time and space scales; - to develop and test an integrated holistic approach that can be able to assess the effects of climate change on the terrestrial hydrologic cycle and on water resources systems. The project is focused on two main aspects : 1) The comparison of models : 3 different types of models are used and compared : - the IRM/KMI uses a spatially non-discretized model (the IRMB model) and develops a spatially semi-discretized model (the SCHEME model); - the ILWM-KUL uses an existing spatially discretized integrated model, the MIKE-SHE model; - the HA-FUSAG, HG-KUL, LGIH-ULG and CE-ULG teams develop and use a spatially-discretized integrated model, composed of existing sub-models of land surface (soils), groundwater and surface water (the MOHISE model). These models have been tested and compared using the same data set, to assess their capabilities to represent the different phases of the terrestrial hydrological cycle (soil, groundwater, surface water). 2) The simulation of the impacts of climate changes on the terrestrial hydrological cycle : climate change scenarios (monthly changes of meteorological variables) were elaborated on the basis of the results of three GCM (Global Climate Models) experiments provided by the IPCC (International Panel on Climate Change) and tested on the test-basins. During the 4 years-project period (1997-2000), the scientific work has been devoted to the construction, integration and implementation of the models and related data bases. The models were tested, calibrated and validated on a few representative Belgian basins. The selected test-basins are the Gette basin (at Budingen : 600 km²), the Geer basin (at Kanne : 465 km²) and the Ourthe Orientale basin (at Mabompré : 319 km²). The results of this research demonstrate the ability of the models to simulate the functioning of the terrestrial hydrological cycle under the present climate and to take into account the major processes that occur in the soils, groundwater and surface water compartments. The models have been used to assess the effects of potential climate changes on the terrestrial hydrological cycle. [less ▲]

Detailed reference viewed: 20 (7 ULg)
Full Text
Peer Reviewed
See detailStochastic analysis of the effect of heterogeneity and fractures on radionuclide transport in a low-permeability clay layer
Huysmans, Marijke; Dassargues, Alain ULg

in Environmental Geology (2005), 48(7), 920-930

Deep low-permeability clay layers are considered as safe environments for disposal of high-level radioactive waste. In Belgium, the Boom Clay is a candidate host rock for deep geological disposal. In this ... [more ▼]

Deep low-permeability clay layers are considered as safe environments for disposal of high-level radioactive waste. In Belgium, the Boom Clay is a candidate host rock for deep geological disposal. In this study, we analyze the effects of fractures and spatially variable hydraulic conductivity on radionuclide migration through the clay. Fracture geometry and properties are simulated with Monte Carlo simulation. The heterogeneity of hydraulic conductivity is simulated by direct sequential co-simulation using measurements of hydraulic conductivity and four types of secondary variables. The hydraulic conductivity and fracture simulations are used as input for a transport model. Radionuclide fluxes computed with this heterogeneous model are compared with fluxes obtained with a homogeneous model. The output fluxes of the heterogeneous model differ at most 8% from the homogeneous model. The main safety function of the Boom Clay is thus not affected by the fractures and the spatial variability of hydraulic conductivity. [less ▲]

Detailed reference viewed: 24 (3 ULg)
Full Text
Peer Reviewed
See detailStudy of cavernous underground conduits in Nam La (Northwest Vietnam) by an integrative approach
Tam, V. T.; De Smedt, F.; Batelaan, Okke et al

in Hydrogeology Journal (2005), 13(5-6), 675-689

This paper presents the result of an investigation of underground conduits, which connect the swallow holes and the resurgence of a blind river in the tropical, highly karstified limestone Nam La ... [more ▼]

This paper presents the result of an investigation of underground conduits, which connect the swallow holes and the resurgence of a blind river in the tropical, highly karstified limestone Nam La catchment in the NW of Vietnam. The Nam La River disappears underground in several swallow holes near the outlet of the catchment. In the rainy season this results in flooding upstream of the sinkholes. A hypothesis is that the Nam La River resurges at a large cavern spring 4.5 km east of the catchment outlet. A multi-thematic study of the possible connections between the swallow holes and the resurgence was carried out to investigate the geological structure, tectonics, cave structure analysis and discharge time series. The existence of the underground conduits was also tested and proven by tracer experiments. On the basis of a lineament analysis the location of the underground conduits were predicted. A remote sensing derived lineament-length density map was used to track routes from the swallow holes to the resurgence, having the shortest length but highest lineament density. This resulted in a plan-view prediction of underground conduits that matches with the cave and fault development. The functioning of the conduits was further explained by analysing flooding records of a nearby doline, which turns out to act as a temporary storage reservoir mitigating flooding of the catchment outlet area. [less ▲]

Detailed reference viewed: 49 (4 ULg)
Full Text
See detailSimulation of radionuclide mass fluxes in a heterogeneous clay formation locally disturbed by excavation
Huysmans, Marijke; Berckmans, Arne; Dassargues, Alain ULg

in Renard, Philippe; Demougeot-Renard, H.; Froidevaux, R. (Eds.) Geostatistics for Environmental Applications (Proc. of GEOENV’2004) (2005)

Detailed reference viewed: 25 (2 ULg)
Full Text
See detailTravel time simulation of radionuclides in a 200 m deep heterogeneous clay formation locally disturbed by excavation
Huysmans, Marijke; Berckmans, Arne; Dassargues, Alain ULg

in Seventh International Geostatistics Congress (2005)

In the North of Belgium the Boom Clay Formation, at a depth of 200m below surface, is being evaluated as a potential host formation for the disposal of vitrified nuclear waste. The aim of this study is to ... [more ▼]

In the North of Belgium the Boom Clay Formation, at a depth of 200m below surface, is being evaluated as a potential host formation for the disposal of vitrified nuclear waste. The aim of this study is to model the transport of radionuclides through the clay, taking into account the geological heterogeneity and the excavation induced fractures around the galleries in which the waste will be stored. This is achieved by combining a transport model with geostatistical techniques used to simulate the geological heterogeneity and fractures of the host rock formation. In a first phase, 100 simulations of the hydraulic conductivity of the clay are generated by conditional stochastic simulation, using measurements of hydraulic conductivity and 4 types of secondary variables: resistivity logs, gamma ray logs, grain size measurements and descriptions of the lithology. Thereafter, 100 simulations of the fractures around the excavation are generated based on information about the extent, orientation, spacing and aperture of excavation induced fractures, measured around similar galleries. Subsequently, the hydraulic conductivity simulations and the fracture simulations are randomly combined and used as input for a transport model that calculates the transport by advection, diffusion, dispersion, adsorption and decay through the heterogeneous and fractured medium. The effect of “self healing” of the clay formation as a function of time after excavation is taken into account. Finally, this results in 100 breakthrough curves of radionuclides in the aquifers surrounding the Boom Clay, reflecting the uncertainty of travel time through the clay resulting from the uncertainty of the hydraulic conductivity and the fracture distribution. The breakthrough curves can serve as a risk management tool in the evaluation of the suitability of the Boom Clay Formation as a host rock for vitrified nuclear waste storage. [less ▲]

Detailed reference viewed: 33 (4 ULg)
Full Text
Peer Reviewed
See detailLarge-scale groundwater flow and transport modeling: Methodology and application to the Meuse Basin – Belgium
Orban, Philippe ULg; Brouyère, Serge ULg; Corbeanu, Horatiu et al

in Bringing Groundwater Quality Research to the Watershed Scale - Proceedings of GQ2004 (2005)

To meet the requirements of the EU Water Framework Directive, an integrated water management project named PIRENE was initiated by the Walloon Region of Belgium. A partner of this project, the ... [more ▼]

To meet the requirements of the EU Water Framework Directive, an integrated water management project named PIRENE was initiated by the Walloon Region of Belgium. A partner of this project, the Hydrogeology Group of the University of Liège, is in charge of the development of a physically based transient groundwater flow and transport model for the Walloon part of the Meuse Basin (approximately 17 000 km2). To face the problems associated with this large-scale model, a general approach has been developed that combines a hydrogeological database and GIS systems to manage data. Techniques of spatial discretization have been applied that optimize the number of unknowns. For modelling groundwater flow and transport on a large scale, a new numerical approach called the Hybrid Finite Element Mixing Cell (HFEMC) has been implemented in the 3-D simulator SUFT3D. [less ▲]

Detailed reference viewed: 57 (12 ULg)
Full Text
See detailMarché de services en vue de simuler l’impact, sur le régime hydrologique de l’Ourthe, de l’implantation de bassins écrêteurs dans les vallées de l’Ourthe et de l’Amblève (MOHICAN)
Deliège, Jean-François ULg; Bourouag, Mohamed ULg; Dautrebande, Sylvia et al

Report (2004)

Le modèle MOHICAN (« Modèle hydrologique intégré pour le calcul des crues et l’amplitude des niveaux d’eau ») a été développé conjointement par l’Université de Liège (Laboratoire d’hydrodynamique ... [more ▼]

Le modèle MOHICAN (« Modèle hydrologique intégré pour le calcul des crues et l’amplitude des niveaux d’eau ») a été développé conjointement par l’Université de Liège (Laboratoire d’hydrodynamique appliquée, Laboratoire de Géologie de l’Ingénieur et d’Hydrogéologie, Centre d’Etude et de Modélisation de l’environnement) et la Faculté Universitaire des Sciences Agronomiques de Gembloux (Unité d’Hydraulique agricole) pour le compte et avec le support du Ministère de l’Equipement et des Transports, Service d’Etudes Hydrologiques (MET/SETHY) de la Région wallonne. En 2004, le SETHY a demandé aux développeurs du projet de simuler l’impact sur le régime hydrologique de l’Ourthe, de bassins écrêteurs dans les vallées de l’Ourthe et de l’Amblève. Plus spécifiquement, les objectifs de l’étude étaient d’estimer l’efficacité réelle de ces bassins écrêteurs (Les Combes, 16.3 Mm³, Ourthe ; Gran Han, 15.0 Mm³, Ourthe ; Stoumont, 5.7 Mm³, Amblève) pour la diminution des débits de pointe et des hauteurs d’eau, en particulier lors de très grandes crues. Dans le cas des grandes crues testée, les simulations montrent clairement la grande sensibilité des résultats aux différentes combinaisons possibles des bassins écrêteurs et surtout aux lois de gestion à utiliser pour ces bassins : il n’existe pas une loi générale qui donne un résultat maximal pour tous les types de grandes crues, et la gestion combinée des bassins est délicate. [less ▲]

Detailed reference viewed: 23 (6 ULg)