References of "Orban, Philippe"
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See detailMéthodologie de diagnostic environnemental autour de captages d’eau potabilisable sensibles qualitativement du point de vue nitrate
Vandenberghe, Christophe ULiege; Bah, Boubacar Billo ULiege; Orban, Philippe ULiege et al

Report (2015)

Le projet s’inscrit dans le cadre des « contrats de captages » dont la mise en oeuvre est assurée par la SPGE (Société Publique de Gestion de l’Eau) et ce, conformément au contrat de gestion qui lie cette ... [more ▼]

Le projet s’inscrit dans le cadre des « contrats de captages » dont la mise en oeuvre est assurée par la SPGE (Société Publique de Gestion de l’Eau) et ce, conformément au contrat de gestion qui lie cette dernière avec le Gouvernement wallon. L’objectif se décline en trois phases : 1. établir une méthodologie commune de détermination et priorisation des actions à entreprendre autour de captages en vue d’y préserver ou de restaurer la qualité de l’eau ; 2. tester la méthodologie (définition des actions à entreprendre) sur six situations jugées représentatives sur des captages de la SWDE (Société Wallonne des Eaux) ; 3. proposer et coordonner des actions à mettre en oeuvre sur deux ou trois des six sites pilotes. La méthodologie est traduite en logigrammes d’actions qui proposent des démarches communes de diagnostic et d’actions à entreprendre autour de captages en vue d’y préserver ou de restaurer la qualité de l’eau. [less ▲]

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See detailUnderground Pumped Storage Hydroelectricity (UPSH) using abandoned works
Pujades, Estanislao ULiege; Willems, Thibault ULiege; Orban, Philippe ULiege et al

Poster (2015, September 17)

Underground Pumped Storage Hydroelectricity (UPSH) using abandoned works is an interesting alternative to increase the efficiency of some power plants, which cannot regulate the amount of electricity ... [more ▼]

Underground Pumped Storage Hydroelectricity (UPSH) using abandoned works is an interesting alternative to increase the efficiency of some power plants, which cannot regulate the amount of electricity generated according to the demand. UPSH plants can store (pumping water from an underground to an upper reservoir) or produce energy (releasing water from an upper to an underground reservoir) during the low or high demand periods. Two considerations must be taken into account in order to construct an UPSH plant: 1) the alteration of the natural conditions of aquifers and 2), the efficiency of the plant, which depends on the hydraulic head inside the underground reservoir. Obviously, a detailed numerical model must be necessary to design a plant. However, a screening methodology to apply during the early stages of the design of a UPSH plant in order to reject the most disadvantageous sites in a short period of time would be useful. Groundwater flow impacts caused by UPSH plants are analyzed numerically and the main variables involved in the groundwater evolution are identified. The most noticeable effect consists in an oscillation of the groundwater. The hydraulic head around which groundwater oscillates, the magnitude of the oscillations and the time to achieve a pseudo-steady state (magnitude and head reached during oscillations do not vary anymore with time) depend on the boundaries, the parameters of the aquifer and the characteristics of the underground reservoir. From the numerical study, a screening methodology, which is based on existing analytical procedures (solutions for large diameter wells, methodologies for cyclic pumpings and the image well theory), is proposed to assess the main impacts caused in aquifers by UPSH plants and their efficiency regarding the groundwater evolution inside the reservoir. The procedure can be applied in a relatively short period of time and is useful to select those appropriate sites to construct a UPSH plant. [less ▲]

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See detailLanduse change and future flood risk: the influence of micro-scale spatial patterns (FloodLand) - 3rd progress report
Dewals, Benjamin ULiege; Bruwier, Martin ULiege; El Saeid Mustafa, Ahmed Mohamed ULiege et al

Report (2015)

The goal of the project FloodLand is to investigate the complex interactions between landuse change and future flood risk. Landuse change is assumed to be mainly driven by population growth and socio ... [more ▼]

The goal of the project FloodLand is to investigate the complex interactions between landuse change and future flood risk. Landuse change is assumed to be mainly driven by population growth and socio-economic factors. It affects future flood risk by altering catchment hydrology as well as vulnerability in the floodplains; but the feedback effect of (the perception of) changes in flood hazard on landuse evolution is also considered. The research is based on a chain of modelling tools, which represent parts of the natural and human systems, including: landuse change modelling, transportation modelling as an onset for the estimation of indirect flood damage, continuous hydrological modelling (forced by precipitation and temperature data disturbed according to climate change scenarios), as well as efficient hydraulic modelling of inundation flow in the floodplains. Besides reproducing a broad spectrum of processes, the modelling approach spans over multiple scales, from the regional or catchment level down to the floodplain and building levels. This distinctive feature is reflected both within the individual models and through their combination involving fine-scale detailed analyses (or data) embedded within coarser models at a broader level. [less ▲]

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See detailOpen pits or deep mines used for Underground Pumped Storage Hydroelectricity (UPSH): impacts on groundwater exchanges
Pujades, Estanislao ULiege; Willems, Thibault ULiege; Orban, Philippe ULiege et al

Poster (2015, July 08)

UPSH using abandoned works is an attractive alternative to improve the efficiency of power plants, which cannot regulate the amount of electricity generated according to the demand (wind, solar or nuclear ... [more ▼]

UPSH using abandoned works is an attractive alternative to improve the efficiency of power plants, which cannot regulate the amount of electricity generated according to the demand (wind, solar or nuclear). UPSH plants can store (pumping water from an underground to an upper reservoir) or produce energy (releasing water from an upper to an underground reservoir) during the low or high demand periods. However, it is mandatory to determine 1) the impacts caused on aquifers and 2) the role played by the aquifer characteristics in order to assess the suitability of UPSH plants. Numerical simulations are developed in order to ascertain the groundwater flow impacts and the variables involved in the process. Given the earlier stages of our study, results are obtained considering regular pumping-injection cycles and simplifying the shape of the mine/open pit. The most noticeable effect consists in an oscillation of the groundwater. The hydraulic head around which groundwater oscillates, the magnitude of the oscillations and the time to achieve a pseudo-steady state (magnitude and head reached during oscillations do not vary anymore with time) depend on the boundaries, the parameters of the aquifer and the characteristics of the underground reservoir. [less ▲]

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See detailOrigine des fortes teneurs en fluorure dans les eaux souterraines du socle précambrien du Bénin central
Tossou, Yao ULiege; Gesels, Julie ULiege; Alassane, Abdoulkarim et al

Scientific conference (2015, June 25)

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See detailA hydrochemical - isotopic approach for assessing factors controlling the regional pollution of an urban aquifer
Gesels, Julie ULiege; Orban, Philippe ULiege; Popescu, Ileana-Cristina et al

Poster (2015, June 24)

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ... [more ▼]

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ammonium. The sources of those contaminants are numerous: brownfields, urban waste water, subsurface acid mine drainage from former coal mines, atmospheric deposits related to former pollutants emissions in the atmosphere ... Sulfate, nitrate and ammonium are both typical pollutants of the aquifer and tracers of the possible pollution sources. In the Water Framework Directive context, a detailed hydrogeochemical characterization of groundwater was performed. The aim is to determine the origin of the inorganic contaminations, the main processes contributing to poor groundwater quality and the spatial extent of the contaminations. A large hydrochemical sampling campaign was performed, based on 71 selected representative sampling locations, to better characterize the different vectors (end-members) of contamination of the alluvial aquifer and their respective contribution to groundwater contamination in the area. Groundwater samples were collected and analyzed for major and minor compounds and metallic trace elements. The analyses also include stable isotopes in water, sulfate, nitrate, ammonium, dissolved inorganic carbon, boron and strontium. Different hydrogeochemical approaches are combined to obtain a global understanding of the hydrogeochemical processes at regional scale. Hydrochemical interpretations are based on classical diagrams, spatial distribution maps, geochemical equations, multivariate statistics such as self-organizing maps and isotopic analyses. With this combined approach, the location of the contaminant sources and most contaminated sectors of the alluvial aquifer together with a better understanding of geochemical processes involved are obtained. Redox processes strongly influence the composition of groundwater, specifically for compounds degrading the quality of groundwater in the area (sulfate, nitrate and ammonium). The highest concentrations of sulfate can be associated with the post-mining stage in the acid mine drainage process. Various reactions involving nitrogen compounds have been identified and allow a better understanding of causes of high concentrations of ammonium and nitrate. Denitrification and sulphate reduction are also demonstrated based on isotopic ratios. [less ▲]

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See detailUse and utility of combined solute and heat tracer tests for characterizing hydrogeothermal properties of an alluvial aquifer
Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre ULiege et al

Conference (2015, June 05)

Using heat as a tracer together with a solute tracer is interesting for characterizing hydrogeothermal properties of the underground. These properties are particularly needed to dimension any low ... [more ▼]

Using heat as a tracer together with a solute tracer is interesting for characterizing hydrogeothermal properties of the underground. These properties are particularly needed to dimension any low temperature geothermal project using an open doublet system (pumping-reinjection) in a shallow aquifer. The tracing experiment, conducted in the alluvial aquifer of the River Meuse (Hermalle near Liège), consisted in injecting simultaneously heated water at 40°C and a dye tracer in a piezometer and monitoring the evolution of temperature and tracer concentration in the recovery well and in nine monitoring piezometers located in three transects with regards to the main groundwater flow direction. The breakthrough curves measured in the recovery well showed that heat transfer in the alluvial aquifer is slower. All measured results show also that the heat diffusivity is larger than the solute dispersion. These contrasted behaviours are stressed in the lower permeability zones of the aquifer. Inverse modelling is applied for calibrating the numerical simulation of the groundwater flow, heat and solute transport. First results are presented showing that the density effect must be taken into account and that, as expected, the most important parameter to be calibrated accurately is the hydraulic conductivity. [less ▲]

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See detailModélisation de la remontée des eaux dans les anciennes mines de charbon : un outil pour détecter les seuils de risques d’inondation en plaine alluviale de la Meuse près de Liège (Belgique)
Dassargues, Alain ULiege; Wildemeersch, Samuel; Orban, Philippe ULiege et al

in Des villes et des territoires sobres et sûrs, Synthèse des interventions (2015, June 03)

La plaine alluviale de la Meuse occupe la partie centrale du bassin charbonnier de Liège. Durant les exploitations minières, les niveaux d’eau des aquifères avaient été rabattus par des pompages d’exhaure ... [more ▼]

La plaine alluviale de la Meuse occupe la partie centrale du bassin charbonnier de Liège. Durant les exploitations minières, les niveaux d’eau des aquifères avaient été rabattus par des pompages d’exhaure. Des galeries d’exhaure creusées à partir des pieds de versant dans la vallée de la Meuse contribuaient également à dénoyer le gisement. La fermeture des dernières exploitations minières durant les années 70 et 80 a été le plus souvent assortie d’un arrêt des opérations de pompage qui y sont associées. Ceci a induit une remontée significative des eaux souterraines avec des conséquences indésirables possibles. Les modèles hydrogéologiques peuvent grandement aider à simuler les écoulements des eaux souterraines dans le contexte particulier des travaux miniers. Cependant, les techniques de modélisation classiques ne sont pas adaptées à ce contexte car le milieu est fortement perturbé par les anciens travaux et les réseaux de galeries. Par conséquent, des techniques de modélisation spécifiques ont été développées. Il s'agit d'une combinaison de modèles de boîte (ne nécessitant que quelques paramètres) pour calculer les niveaux d'eau moyens dans les zones exploitées, avec une modélisation physiquement basée et spatialement distribuée représentant explicitement les zones inexploitées et prenant en compte les interactions entre ces deux sous-domaines. Grâce à ce couplage, les échanges d'eau entre les zones exploitées et inexploitées sont explicitement pris en compte. La méthode permet de simuler la remontée des eaux souterraines après la fermeture des mines et des phénomènes associés tels que les 'coups d'eau' produits par les galeries drainantes. Les concepts et équations de la méthode sont présentés et illustrés sur des cas synthétiques, puis sur l'application de la zone de Cheratte-Blégny. [less ▲]

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See detailImpact des changements climatiques sur la principale réserve en eau souterraine alimentant la ville de Liège (Belgique)
Goderniaux, Pascal; Orban, Philippe ULiege; Compère, Jean-Michel et al

in Des villes et des territoires sobres et sûrs, Synthèse des interventions (2015, June 02)

Le changement climatique amène de nouvelles 'pressions' sur les ressources en eaux de surface et souterraines dans de nombreuses zones du monde. Des travaux scientifiques sont nécessaires pour aider les ... [more ▼]

Le changement climatique amène de nouvelles 'pressions' sur les ressources en eaux de surface et souterraines dans de nombreuses zones du monde. Des travaux scientifiques sont nécessaires pour aider les gestionnaires de l'eau à planifier les changements futurs. Un générateur de climats transitoire sophistiqué est utilisé en combinaison avec une modélisation intégrée hydrologique (HydroGeoSphere) pour évaluer les impacts sur les ressources en eaux souterraines de façon probabiliste. Cette nouvelle méthodologie est appliquée pour l'aquifère crayeux de Hesbaye (bassin Geer en Belgique) qui est le principal réservoir d'eau souterraine pour l'alimentation de la ville de Liège. Les sources d'incertitude étudiées sont les suivantes: (1) l'incertitude liée à la calibration du modèle hydrologique, en utilisant 'UCODE_2005'; (2) l'incertitude liée aux modèles climatiques mondiaux et régionaux (GCM et RCM); (3) l'incertitude liée à la variabilité naturelle du climat, en utilisant des scénarios stochastiques de changement climatique locaux. 100 changements climatiques équiprobables scénarios ont été générés sur 2010-2085 pour chacun des six RMC différents. Les résultats montrent que bien que les intervalles de confiance à 95% calculés autour des niveaux piézométriques calculés restent importants, l'effet du changement climatique devient clair et plus prononcé que la variabilité naturelle du climat d'ici 2085. Cette méthodologie constitue une réelle amélioration dans le domaine des prévisions de l'évolution des réserves en eau souterraine dans des conditions de changement climatique car il permet aux gestionnaires d'analyser les risques et prendre des décisions en toute connaissance du degré de confiance des résultats. [less ▲]

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See detailLanduse change and future flood risk: an integrated and multi-scale approach
Dewals, Benjamin ULiege; Bruwier, Martin ULiege; Mohamed El Saeid Mustafa, Ahmed ULiege et al

in E-proceedings of the 36th IAHR World Congress (2015, June)

The goal of this research is a better understanding of the complex interactions between landuse change and future flood risk. Landuse change is mainly driven by population growth and socio-economic ... [more ▼]

The goal of this research is a better understanding of the complex interactions between landuse change and future flood risk. Landuse change is mainly driven by population growth and socio-economic factors. It affects future flood risk by altering catchment hydrology and vulnerability in the floodplains, as well as through the feedback effect that changes in flood hazard may have on landuse evolution. The research is based on a chain of modelling tools, including: stochastic landuse change modelling, traffic modelling as well as Land-Use and Transport Interactions models, continuous hydrological modelling and efficient hydraulic modelling of floodplains inundation. The coupling of these modelling tools will allow assessing direct and indirect impacts of land use change on future flood risk, while considering the uncertainties related to each of these processes and their combinations at a 2100 time horizon. [less ▲]

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See detailProcess-based method for groundwater resource vulnerability mapping with regards to solute contamination at the surface
Popescu, Cristina; Brouyère, Serge ULiege; Orban, Philippe ULiege et al

Conference (2015, May 26)

Numerous groundwater vulnerability methods have been developed taking into consideration a variable number of factors. The most common techniques are based on calculation of an index expressing the ... [more ▼]

Numerous groundwater vulnerability methods 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. However, it has been shown that different overlay and index methods applied to the same system can yield dramatically dissimilar results (among others, Gogu et al., 2003). 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 process-based point of view is proposed and based on three factors describing a pollution event (Brouyère et al., 2001): (1) the transit time from the source to the target, (2) the duration of the contamination breakthrough at the target, (3) the ratio between the maximum concentration at the target to the released concentration at the contamination source. The assessment can then be based on the impulse response at the ‘target’ to a Dirac-type solicitation (point, unit mass, instantaneous source of pollution), considering only physical hydrodispersive processes for intrinsic vulnerability and both physical and biochemical processes for specific vulnerability. The breakthrough curve obtained after a vertical transfer through the overlying layers can be computed pixel by pixel. Automatically processing the columns with identical characteristics, 1D partially saturated flow and solute transport computations are performed. Different maps are obtained for the three above mentioned factors. On the basis of these results, different vulnerability maps can be built according to the weighting coefficients agreed by the local community or decision makers. This concept allows a clear distinction between conventional aspects and process-based results in the building of a final vulnerability indicator. This methodology has the further advantage to consider the possible impact of runoff conditions occurring at the land surface and possibly leading to lateral contamination of groundwater through downstream preferential infiltration features. To solve this problem, Popescu et al. (2004 & 2008) and Dassargues et al. (2009) proposed a method for quantifying a lateral “dangerosity” coefficient using runoff coefficients based on land use, slopes, and soil properties. A test application is illustrated on a case-study located in a limestone basin in Belgium. [less ▲]

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