References of "Dassargues, Alain"
     in
Bookmark and Share    
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: 16 (3 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: 15 (2 ULg)
Full Text
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 ▲]

Detailed reference viewed: 86 (15 ULg)
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: 55 (7 ULg)
See detailCarte hydrogéologique de Wallonie, Vielsalm-Houvegnez 56/1-2, 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 : aout 2012 (2012)

Detailed reference viewed: 26 (0 ULg)
See detailCarte hydrogéologique de Wallonie,Elsenborn-Langert 50/3-4, Dreiherrenwald, 50A/1
Gilson, Mylene; Briers, Pierre ULg; Ruthy, Ingrid ULg et al

Cartographic material (2012)

Detailed reference viewed: 22 (0 ULg)
See detailCarte hydrogéologique de Wallonie,Elsenborn-Langert 50/3-4, Dreiherrenwald, 50A/1, 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 : aout 2012 (2012)

Detailed reference viewed: 10 (2 ULg)
See detailCarte hydrogéologique de Wallonie, Reinartzhof – Hoscheit, 43/7-8
Ruthy, Ingrid ULg; Briers, Pierre ULg; Gilson, Mylene et al

Cartographic material (2012)

Detailed reference viewed: 21 (4 ULg)
See detailCarte hydrogéologique de Wallonie, Reinartzhof – Hoscheit, 43/7-8, 1/25.000 : [notice explicative]
Ruthy, Ingrid ULg; Briers, Pierre ULg; Gilson, Mylene et al

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

Detailed reference viewed: 13 (2 ULg)
Full Text
Peer Reviewed
See detailModeling the effect of clay drapes on pumping test response in a cross-bedded aquifer using multiple-point geostatistics
Huysmans, Marijke; Dassargues, Alain ULg

in Journal of Hydrology (2012), 450-451

This study investigates whether fine-scale clay drapes can cause an anisotropic pumping test response at a much larger scale. A pumping test was performed in a sandbar deposit consisting of cross-bedded ... [more ▼]

This study investigates whether fine-scale clay drapes can cause an anisotropic pumping test response at a much larger scale. A pumping test was performed in a sandbar deposit consisting of cross-bedded units composed of materials with different grain sizes and hydraulic conductivities. The measured drawdown values in the different observation wells reveal an anisotropic or elliptically-shaped pumping cone. The major axis of the pumping ellipse is parallel with the strike of cm to m-scale clay drapes that are observed in several outcrops. To determine (1) whether this large-scale anisotropy can be the result of fine-scale clay drapes and (2) whether application of multiple-point geostatistics can improve interpretation of pumping tests, this pumping test is analyzed with a local 3D groundwater model in which fine-scale sedimentary heterogeneity is modelled using multiple-point geostatistics. To reduce CPU and RAM demand of the multiple-point geostatistical simulation step, edge properties indicating the presence of irregularly-shaped surfaces are directly simulated. Results show that the anisotropic pumping cone can be attributed to the presence of the clay drapes. Incorporating fine-scale clay drapes results in a better fit between observed and calculated drawdowns. These results thus show that fine-scale clay drapes can cause an anisotropic pumping test response at a much larger scale and that the combined approach of multiple-point geostatistics and cell edge properties is an efficient method for integrating fine-scale features in larger scale models. [less ▲]

Detailed reference viewed: 60 (7 ULg)
Full Text
See detailGroundwater issues create challenges for engineers
Dassargues, Alain ULg

Scientific conference (2012, June 15)

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailEstimation of hydraulic conductivity and its uncertainty from grain-size data using GLUE and artificial neural networks
Rogiers, Bart; Mallants, Dirk; Batelaan, Okke et al

in Mathematical Geosciences (2012), 44(6), 739-763

Various approaches exist to relate saturated hydraulic conductivity (Ks) to grain-size data. Most methods use a single grain-size parameter and hence omit the information encompassed by the entire grain ... [more ▼]

Various approaches exist to relate saturated hydraulic conductivity (Ks) to grain-size data. Most methods use a single grain-size parameter and hence omit the information encompassed by the entire grain-size distribution. This study compares two data-driven modelling methods, i.e.multiple linear regression and artificial neural networks, that use the entire grain-size distribution data as input for Ks prediction. Besides the predictive capacity of the methods, the uncertainty associated with the model predictions is also evaluated, since such information is important for stochastic groundwater flow and contaminant transport modelling. Artificial neural networks (ANNs) are combined with a generalized likelihood uncertainty estimation (GLUE) approach to predict Ks from grain-size data. The resulting GLUE-ANN hydraulic conductivity predictions and associated uncertainty estimates are compared with those obtained from the multiple linear regression models by a leave-one-out cross-validation. The GLUE-ANN ensemble prediction proved to be slightly better than multiple linear regression. The prediction uncertainty, however, was reduced by half an order of magnitude on average, and decreased at most by an order of magnitude. This demonstrates that the proposed method outperforms classical data-driven modelling techniques. Moreover, a comparison with methods from literature demonstrates the importance of site specific calibration. The dataset used for this purpose originates mainly from unconsolidated sandy sediments of the Neogene aquifer, northern Belgium. The proposed predictive models are developed for 173 grain-size -Ks pairs. Finally, an application with the optimized models is presented for a borehole lacking Ks data. [less ▲]

Detailed reference viewed: 69 (7 ULg)