References of "Dassargues, Alain"
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See detailCoupling heat and salt tracer experiment for the estimation of heat transfer and solute transport parameters
Wildemeersch, Samuel ULg; Jamin, Pierre ULg; Orban, Philippe ULg et al

Conference (2013, April 22)

Geothermal energy is a promising source of energy in the context of sustainable development. Therefore, very low enthalpy geothermal systems (open or closed) are increasingly considered for heating or ... [more ▼]

Geothermal energy is a promising source of energy in the context of sustainable development. Therefore, very low enthalpy geothermal systems (open or closed) are increasingly considered for heating or cooling houses and offices using groundwater energy. However, prior to the development of such systems, a feasibility study and an impact study of the system on groundwater ressources are required. Thereliability of such studies is highly dependent on the quality of the estimation of heat transfer parameters. This highlights the necessity of estimating properly such parameters. The objective of this study is to combine the use of heat and salt tracers to estimate simultaneously heat transfer and solute transport parameters in an alluvial aquifer. Additionally, coupling heat and salt tracing experiments is particularly useful for comparing heat transfer and solute transport processes occurring in the subsurface. An experimental field site, located near Liege (Belgium), is equipped with 21 piezometers drilled in the alluvial deposits of the Meuse River. These alluvial deposits are composed of a loess layer (3 m) overlying a sand and gravel layer which constitutes the alluvial aquifer (7 m). The coupled tracing experiment consists in injecting simultaneously heated water and salt in a piezometer and monitoring the evolution of groundwater temperature and salt concentration in a series of control panels set perpendicularly to groundwater flow. This coupled tracing experiment is then simulated using a numerical model. The estimation of heat transfer and solute transport parameters is obtained by calibrating this numerical model using inversion tools. The present study proposes a methodology coupling heat and salt tracing experiment for estimating heat transfer parameters at the field scale. Furthermore, this coupled tracing experiment shows that the comportment of heat and solute in the subsurface presents key differences. [less ▲]

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See detailThe effect of heterogeneity of diffusion parameters on chloride transport in low-permeability argillites
Huysmans, Marijke; Dassargues, Alain ULg

in Environmental Earth Sciences (2013), 68(7), 1835-1848

Understanding flow and transport in low-permeability media is very important in the context of nuclear waste disposal, oil and gas reservoirs and long term evolution of groundwater systems. In low ... [more ▼]

Understanding flow and transport in low-permeability media is very important in the context of nuclear waste disposal, oil and gas reservoirs and long term evolution of groundwater systems. In low-permeability media, transport by diffusion is often the most important mass transport process. This study investigates the effect of the heterogeneity of diffusion parameters on mass transport in low-permeability media. A geostatistical approach for integrating heterogeneity of diffusion parameters in groundwater flow and transport models is proposed and applied to the Toarcian argillites in France which are studied in the framework of feasibility of storing radioactive waste in deep clayey massifs. Stochastic fields of the diffusion parameters of the Toarcian argillites (France) are generated based on 64 measured values of diffusion coefficient and diffusion accessible porosity and used as input for a 3D local-scale groundwater flow and transport model. The chloride concentrations computed by these heterogeneous models are compared to the measured chloride concentrations and to concentrations calculated with a model in which the Toarcian argillites are subdivided into several homogeneous zones. The heterogeneous simulations result in a slightly better correspondence between measured and calculated values and have the additional advantage that the measured diffusion coefficient values in the Toarcian are perfectly honored in the model. This study shows that small-scale variability of diffusion parameters has a significant effect on solute concentrations and omitting this heterogeneity may be a problem in transport calculations in low-permeability media, depending on the specific setting and objectives of the study. [less ▲]

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See detailCarte hydrogéologique de Wallonie, Fléron-Verviers 42/7-8
Ruthy, Ingrid ULg; Dassargues, Alain ULg

Cartographic material (2013)

Detailed reference viewed: 10 (1 ULg)
See detailCarte hydrogéologique de Wallonie, Limbourg - Eupen 43/5-6
Ruthy, Ingrid ULg; Dassargues, Alain ULg

Cartographic material (2013)

Detailed reference viewed: 16 (0 ULg)
See detailCarte hydrogéologique de Wallonie, Limbourg - Eupen 43/5-6, 1/25.000 : [notice explicative]
Ruthy, Ingrid ULg; Dassargues, Alain ULg

Book published by Service Public de Wallonie, DGARNE - Actualisation partielle: mars 2013 - Première version: aout 2010 (2013)

Detailed reference viewed: 8 (1 ULg)
See detailCarte hydrogéologique de Wallonie, Fléron-Verviers 42/7-8, 1/25.000 : [notice explicative]
Ruthy, Ingrid ULg; Dassargues, Alain ULg

Book published by Service Public de Wallonie, DGARNE - Actualisation partielle: mars 2013 - Première édition : juin 2010 (2013)

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See detailTransport of dissolved Si from soil to river: a conceptual mechanistic model
Ronchi, Benedicta; Vandevenne, Floor; Pena Barao, Ana Lucia et al

in Silicon (2013), 5(1), 115-133

This paper reviews the processes which determine the concentrations of dissolved silicon (DSi) in soil water and proposes a mechanistic model for understanding the transport of Si through a typical podzol ... [more ▼]

This paper reviews the processes which determine the concentrations of dissolved silicon (DSi) in soil water and proposes a mechanistic model for understanding the transport of Si through a typical podzol soil to the river. DSi present in natural waters originates from the dissolution of mineral and amorphous Si sources in the soil. However, the DSi concentration in natural waters will be dependent on both dissolution and deposition/precipitation processes. The net DSi export is controlled by soil composition like (mineralogy and saturated porosity) as well as water composition (pH, concentrations of organic acids, CO2 and electrolytes). These state variables together with production, polymerization and adsorption equations constitute a mechanistic framework determining DSi concentrations. For a typical soil profile in a temperate climate, we discuss how the values of these key controls differ in each soil horizon and how it influences the DSi transport. Additionally, the impact of external forcings such as seasonal climatic variations and land use, is evaluated. This model is a first step to better understand Si transport processes in soils and should be further validated with field measurements. [less ▲]

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See detailThe usefulness of CPTs for deterministic, spatially heterogeneous, large-scale aquitard parametrisation
Rogiers, Bart; Mallants, Dirk; Batelaan, Okke et al

in Oswald, S.E.; Kolditz, O.; Attinger, S. (Eds.) Models - Repositories of Knowledge (2012, December)

Aquitards can be effectively parameterised and incorporated in a groundwater flow model by using standard cone penetration tests (CPTs). Several conceptually different realizations of an aquitard’s ... [more ▼]

Aquitards can be effectively parameterised and incorporated in a groundwater flow model by using standard cone penetration tests (CPTs). Several conceptually different realizations of an aquitard’s hydraulic conductivity field were evaluated based on: (i) conventional methods of soil behaviour type classification, (ii) recent relationships from the literature, and (iii) novel site-specific relations with hydraulic conductivity. We show that use of most of these CPT-based hydraulic conductivity estimations in groundwater flow modelling effectively enhance model performance based on absolute head values and gradients across the aquitard. Conceptual models that considered a spatially heterogeneous hydraulic conductivity for the aquitard performed better than the reference case with a uniform aquitard hydraulic conductivity. However, the hydraulic conductivity of thin heavy clay lenses, characteristic of the aquitard present in our study area, cannot be captured using these continuum approaches. The latter leads to a bias in the direct hydraulic conductivity predictions; an alternative is to invoke inverse modelling with the heterogeneous parameter fields. To address this issue, the concept of the boundary energy associated with the CPT signal is also introduced for characterising the presence of heavy clay lenses. Overall, the CPT-based concepts provide more accurate, robust, and high-resolution data-based parameterisation of the studied aquitard. [less ▲]

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See detailCarte hydrogéologique de Wallonie, Sart-Xhoffrai 50/1-2
Gilson, Mylene; Briers, Pierre ULg; Ruthy, Ingrid ULg et al

Cartographic material (2012)

Detailed reference viewed: 10 (0 ULg)
See detailCarte hydrogéologique de Wallonie, Sart-Xhoffrai 50/1-2, 1/25.000 : [notice explicative]
Gilson, Mylene; Briers, Pierre ULg; Ruthy, Ingrid ULg et al

Book published by Service Public de Wallonie, DGARNE - Version provisoire : décembre 2012 (2012)

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See detailEvaluation qualitative et quantitative des ressources en eau souterraine dasn le bassin de Dargol (Liptako – Niger)
Abdou Babaye, Maman Sani ULg; Boureimane, Ousmane; Orban, Philippe ULg et al

Conference (2012, November)

Située dans la partie Sud-Ouest du Niger, le bassin de Dargol appartient à la région de socle précambrien du Liptako. L’étude du chimisme des eaux souterraines révèle trois types de faciès dont le plus ... [more ▼]

Située dans la partie Sud-Ouest du Niger, le bassin de Dargol appartient à la région de socle précambrien du Liptako. L’étude du chimisme des eaux souterraines révèle trois types de faciès dont le plus dominant est le type bicarbonaté calcique à magnésien (65%). Environ 47% d’ouvrages ont des teneurs en nitrates dépassant largement les normes OMS (50 mg/l). Les teneurs en isotopes stables (δ18O, δ2H) de la nappe indiquent deux mécanismes de recharge: une recharge directe par les eaux des pluies peu ou pas évaporées, et une recharge indirecte par les eaux évaporées issues des lits de koris et des eaux de surface. L’analyse des teneurs en tritium de la nappe indique que la recharge est récente pour la majorité des points investigués. En revanche, dans le secteur à faibles teneurs en tritium, le taux de renouvellement semble être faible voire nul. [less ▲]

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See detailCarte hydrogéologique de Wallonie, Stavelot-Malmédy 50/5-6
Briers, Pierre ULg; Gilson, Mylene; Ruthy, Ingrid ULg et al

Cartographic material (2012)

Detailed reference viewed: 10 (0 ULg)
See detailCarte hydrogéologique de Wallonie, Stavelot-Malmédy 50/5-6, 1/25.000 : [notice explicative]
Briers, Pierre ULg; Gilson, Mylene; Ruthy, Ingrid ULg et al

Book published by Service Public de Wallonie, DGARNE - Version provisoire : novembre 2012 (2012)

Detailed reference viewed: 12 (1 ULg)
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See detailEtude hydrogéochimique des eaux de la nappe du Continental Terminal du Saloum : Relation eau de surface – eau souterraine
Dieng, Ndeye Maguette ULg; Orban, Philippe ULg; FAYE, Serigne et al

Conference (2012, November)

L’évaluation de l’état actuel de la qualité des eaux de la nappe du Continental Terminal et du fleuve Saloum a été réalisée grâce à l’analyse de 44 échantillons d’eau souterraine et 3 échantillons d’eau ... [more ▼]

L’évaluation de l’état actuel de la qualité des eaux de la nappe du Continental Terminal et du fleuve Saloum a été réalisée grâce à l’analyse de 44 échantillons d’eau souterraine et 3 échantillons d’eau de surface collectés en saison humide. Les analyses des ions majeurs et les mesures de la conductivité électrique (CE) ont démontré que les eaux de la nappe du CT du Saloum étaient largement contaminées par la salinisation (CE comprise entre à 750 et 2800 µS/cm) au niveau de la zone côtière à l’ouest et au nord sur une bande longeant le fleuve Saloum. Dans ces zones, les eaux ont désormais des faciès chimiques chlorurés sodiques venant de faciès au départ bicarbonatés calciques des eaux souterraines peu contaminées. Au niveau de certains points, la composition des eaux souterraines devient sensiblement la même que celle des eaux du fleuve Saloum. Les diagrammes binaires (Na versus Cl, Na/Cl versus Cl, [Ca + Mg] versus HCO3 et [(Ca+Mg) - (HCO3+SO4)] versus (Na-Cl)) ont permis de définir les processus géochimiques et les phénomènes de mélange impliqués dans la minéralisation des eaux. Suivant la répartition des valeurs de conductivité électrique et des types d’eaux, une zonation a été cartographiée [less ▲]

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See detailCarte hydrogéologique de Wallonie, Vielsalm-Houvegnez 56/1-2
Briers, Pierre ULg; Gilson, Mylene; Ruthy, Ingrid ULg et al

Cartographic material (2012)

Detailed reference viewed: 23 (4 ULg)