References of "Orban, Philippe"
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See detailWater chemical evolution in Underground Pumped Storage Hydropower plants and induced consequences
Pujades, Estanislao ULiege; Orban, Philippe ULiege; Jurado Elices, Anna ULiege et al

in Energy Procedia (2017), 125

Underground Pumped Storage Hydropower (UPSH) is an alternative to manage the electricity production in flat regions. UPSH plants consist of two reservoirs of which at least one is underground. For this ... [more ▼]

Underground Pumped Storage Hydropower (UPSH) is an alternative to manage the electricity production in flat regions. UPSH plants consist of two reservoirs of which at least one is underground. For this last reservoir, abandoned mines could be considered. UPSH related activities may induce hydrochemical variations, such as the increase of the oxygen (O2) partial pressure (pO2), which may entail negative consequences in terms of environment and efficiency, especially in coal mined areas where the presence of sulfide minerals is common. This work assesses the main expected environmental impacts that UPSH using abandoned coal mines may induce. [less ▲]

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See detailWater chemical evolution in Underground Pumped Storage Hydropower plants and induced consequences.
Pujades, Estanislao ULiege; Orban, Philippe ULiege; Jurado Elices, Anna ULiege et al

Conference (2017, April 27)

Underground Pumped Storage Hydropower (UPSH) using abandoned mines is an alternative to manage the elec- tricity production in flat regions. UPSH plants consist of two reservoirs; the upper reservoir is ... [more ▼]

Underground Pumped Storage Hydropower (UPSH) using abandoned mines is an alternative to manage the elec- tricity production in flat regions. UPSH plants consist of two reservoirs; the upper reservoir is located at the surface or at shallow depth, while the lower reservoir is underground. These plants have potentially less constraints that the classical Pumped Storage Hydropower plants because more sites are available and impacts on landscape, land use, environment and society seem lower. Still, it is needed to consider the consequences of the groundwater exchanges occurring between the underground reservoir and surrounding porous media. Previous studies have been focused on the influence of these groundwater exchanges on the efficiency and on groundwater flow impacts. However, hydrochemical variations induced by the surface exposure of pumped water and their consequences have not been yet addressed. The objective of this work is to evaluate the hydrochemical evolution of the water in UPSH plants and its effects on the environment and on the UPSH efficiency. The problem is studied numerically by means of reactive transport modelling. Different scenarios are considered varying the chemical properties of the surrounding porous medium and groundwater. Results show that the dissolution and/or precipitation of some compounds may affect (1) the groundwater quality, and (2) the efficiency and the useful life of the used pumps and turbines of the UPSH system. [less ▲]

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See detailUnderground pumped storage hydropower plants using open pit mines: How do groundwater exchanges influence the efficiency?
Pujades, Estanislao ULiege; Orban, Philippe ULiege; Bodeux, Sarah ULiege et al

in Applied Energy (2017), 190

Underground Pumped Storage Hydropower (UPSH) is a potential alternative to manage electricity production in flat regions. UPSH plants will interact with the surrounding porous medium through exchanges of ... [more ▼]

Underground Pumped Storage Hydropower (UPSH) is a potential alternative to manage electricity production in flat regions. UPSH plants will interact with the surrounding porous medium through exchanges of groundwater. These exchanges may impact the surrounding aquifers, but they may also influence the efficiency of the pumps and turbines because affecting the head difference between the reservoirs. Despite the relevance for an accurate efficiency assessment, the influence of the groundwater exchanges has not been previously addressed. A numerical study of a synthetic case is presented to highlight the importance of considering the groundwater exchanges with the surrounding porous medium. The general methodology is designed in order to be further applied in the decision making of future UPSH plants introducing each case specific complexity. The underground reservoir of a hypothetical UPSH plant, which consists in an open pit mine, is considered and modelled together with the surrounding porous medium. Several scenarios with different characteristics are simulated and their results are compared in terms of (1) head difference between the upper and lower reservoirs and (2) efficiency by considering the theoretical performance curves of a pump and a turbine. The results show that the efficiency is improved when the groundwater exchanges increase. Thus, the highest efficiencies will be reached when (1) the underground reservoir is located in a transmissive porous medium and (2) the walls of the open pit mine do not constrain the groundwater exchanges (they are not waterproofed). However, a compromise must be found because the characteristics that increase the efficiency also increase the environmental impacts. Meaningful and reliable results are computed in relation to the characteristics of the intermittent and expected stops of UPSH plants. The frequency of pumping and injection must be considered to properly configure the pumps and turbines of future UPSH plants. If not, pumps and turbines could operate far from their best efficiency conditions. [less ▲]

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See detailFactors controlling the evolution of groundwater dynamics and chemistry in the Senegal River Delta
Gning, Abdoul Aziz; Orban, Philippe ULiege; Gesels, Julie ULiege et al

in Journal of Hydrology: Regional Studies (2017), 10

tStudy region: Senegal River Delta. Study focus: The Senegal River Delta is a strategic region for the development of irri-gated agriculture. Despite a Sahelian climatic context, the management of the ... [more ▼]

tStudy region: Senegal River Delta. Study focus: The Senegal River Delta is a strategic region for the development of irri-gated agriculture. Despite a Sahelian climatic context, the management of the river withdams ensures water availability throughout the year. With the intensification of agri-culture, degradation of cultivated soils is observed, mostly linked to the existence of ashallow salty aquifer. In this context, regional surveys were performed to characterizegroundwater–surface water interactions and to identify the impact of artificial river man-agement and agricultural intensification on the evolution of groundwater dynamics andchemistry.New hydrological insights for the region: Results show that groundwater far away from riversand outside irrigated plots has evolved from marine water to brines under the influenceof evapotranspiration. Near rivers, salinity of groundwater is lower than seawater andgroundwater mineralization seems to evolve in the direction of softening through cationicexchanges related to permanent contact with fresh water. Despite large volumes of waterused for rice cultivation, groundwater does not show any real softening trend in the culti-vated parcels. Results show that the mechanisms that contribute to repel salt water fromthe sediments correspond to a lateral flush near permanent surface water streams and notto vertical drainage and dilution with rainfall or irrigation water. It is however difficultto estimate the time required to come back to more favorable conditions of groundwatersalinity. [less ▲]

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See detailLanduse change and future flood risk: the influence of micro-scale spatial patterns (FloodLand) - 5th progress report
Dewals, Benjamin ULiege; Bruwier, Martin ULiege; El Saeid Mustafa, Ahmed Mohamed ULiege et al

Report (2017)

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 detailTemporal changes in groundwater quality of the Saloum coastal aquifer
Dieng, Ndeye Maguette ULiege; Orban, Philippe ULiege; Otten, Joël ULiege et al

in Journal of Hydrology: Regional Studies (2017), 9

Abstract Study region: Groundwater in the southern part of the Saloum Basin in Senegal. Study focus: The Saloum estuary is a hypersaline and ‘inverse’ estuary where the salinity of river water increases ... [more ▼]

Abstract Study region: Groundwater in the southern part of the Saloum Basin in Senegal. Study focus: The Saloum estuary is a hypersaline and ‘inverse’ estuary where the salinity of river water increases in the upstream direction. This region is problematic in that due to the underlain superficial Continental Terminal aquifer bordered by the hypersaline estuary constitutes the unique fresh groundwater reservoir for water supply for its estimated 466,000 residents living in 18 rural districts (belonging to the regions of Fatick, Kaolack and Kaffrine). This is of high value given that the deep Maastrichtian aquifer (200-300m depth) is saline. This study aims to describe and understand temporal changes in the chemical and isotopic compositions of groundwater, the geochemical processes and especially the groundwater salinization. New hydrological insights for the region: The analytical data were discriminated into 3 groups on the basis of the water types. Na-Cl, Ca-Cl and Ca-SO4 rich waters derived from saline water intrusion at the vicinity of the Saloum River accompanied by ion exchange reactions and pollution dominate the first group. The second group located mainly in the centre and eastern parts of the region is featured fresh groundwater of Ca-HCO3 derived from calcite dissolution reactions. The third group of Na-HCO3 type and less mineralized indicates freshening processes by recently infiltrating rainwaters. Slight seasonal chemical variations are observed due to new infiltrating water reaching the water table. High variation in rainfall between the 2 reference years (2003 and 2012) also changes chemical patterns in the groundwater. Chemical evolution of the groundwater is geographically observed and is due to a combination of dilution by recharge, anthropic contamination and seawater intrusion. The results of environmental isotopes (δ18O, δ2H) compared with the local meteoric line indicate that the groundwater has been affected by evaporation processes before and during infiltration. The results also clearly indicate mixing with saltwater and an evolution towards relative freshening between 2003 and 2012 in some wells near the Saloum River. [less ▲]

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See detailInteractions between groundwater and the cavity of an old slate mine used as lower reservoir of an UPSH (Underground Pumped Storage Hydroelectricity): A modelling approach
Bodeux, Sarah ULiege; Pujades, Estanislao ULiege; Orban, Philippe ULiege et al

in Engineering Geology (2017), 217

In the actual evolving energy context, characterized by an increasing part of intermittent renewable sources, the development of energy storage technologies are required, such as pumped storage ... [more ▼]

In the actual evolving energy context, characterized by an increasing part of intermittent renewable sources, the development of energy storage technologies are required, such as pumped storage hydroelectricity (PSH). While new sites for conventional PSH plants are getting scarce, it is proposed to use abandoned underground mines as lower reservoirs for Underground Pumped Storage Hydroelectricity (UPSH). However, the hydrogeological consequences produced by the cyclic solicitations (continuous pumpings and injections) have been poorly investigated. Therefore, in this work, groundwater interactions with the cyclically fill and empty cavity were numerically studied considering a simplified description of a slate mine. Two pumping/injection scenarios were considered, both for a reference slate rock case and for a sensitivity analysis of variations of aquifer hydraulic conductivity value. Groundwater impacts were assessed in terms of oscillations of piezometric heads and mean drawdown around the cavity. The value of the hydraulic conductivity clearly influences the magnitude of the aquifer response. Studying interactions with the cavity highlighted that seepage into the cavity occurs over time. The volume of seeped water varies depending on the hydraulic conductivity and it could become non-negligible in the UPSH operations. These preliminary results allow finally considering first geological feasibility aspects, which could vary conversely according to the hydraulic conductivity value and to the considered groundwater impacts. [less ▲]

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See detailStatistical description of hydrogeological parameters for the main aquifer contexts in Wallonia
Briers, Pierre ULiege; Dollé, Fabien ULiege; Orban, Philippe ULiege et al

Conference (2017, January 20)

The Walloon Region Soil decree proposes a series of guidance documents associated to the procedures for site remediation operations. Among others, one of these documents describes methodologies and tools ... [more ▼]

The Walloon Region Soil decree proposes a series of guidance documents associated to the procedures for site remediation operations. Among others, one of these documents describes methodologies and tools for risk assessment of pollutant leaching from soil to groundwater and for pollutant dispersion through groundwater. These tools require using estimates of hydrogeolocial parameters such as hydraulic conductivity, effective (transport) porosity etc. In this context, an inventory of hydrogeological studies (regional characterization studies, groundwater protection zones…) was performed to identify and collect available field-based measurements for a statistical description and analysis of such data. Complementary to that, a simple geodatabase has been developed to manage and process these data. As expected, these results show contrasted parameter distributions per geological contexts and regions. The objective of the presentation is to describe the methodology followed for the statistical treatment of hydrogeological data and to present the results and associated database. It is believed that such results can be very useful for different hydrogeological studies, in particular as a first referential for groundwater modelling applications and any other studies where statistical descriptions of hydrogeological data are relevant. [less ▲]

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See detailConvention Région wallonne et HGE-ULg Caractérisation complémentaire des masses d’eau dont le bon état dépend d’interactions entre les eaux de surface et les eaux souterraines - Délivrable D1.8 Rapport final
Brouyère, Serge ULiege; Briers, Pierre ULiege; Descy, Jean-Pierre et al

Report (2017)

Mechanisms of interactions between groundwater bodies and rivers whose status and anthropogenic use can be detrimental from a quantitative and qualitative point of view to one or the other of these two ... [more ▼]

Mechanisms of interactions between groundwater bodies and rivers whose status and anthropogenic use can be detrimental from a quantitative and qualitative point of view to one or the other of these two compartments of the water cycle. In addition, contamination of groundwater by nitrate remains relevant. Based on these observations, a study financed by the Public Service of Wallonia was carried out over a period of 39 months to investigate (1) the direction, importance and dynamics of water exchange between groundwater and rivers at the scale of a river section; (2) the impact of these interactions on river baseflows and the river ecological status as a function of groundwater withdrawal and recharge at the catchment scale; (3) mechanisms and timing of transfer and abatement of pollutants (nitrate) between groundwater and surface waters at the watershed scale. The consequences of these mechanisms on the medium- and long-term evolution of groundwater and surface water quality were to be determined. To achieve this, the project relied on the implementation of a series of field investigations essentially focused on the interfaces between surface water and groundwater compartments (soil and unsaturated zone and water-table interface), while acquiring additional information on groundwater. The investigations carried out in the watersheds of the upstream Hoyoux and Triffoy watershed in the Condroz region aimed to provide 6 specific responses to water quantity and quality issued associated with groundwater – surface water interactions in the selected basins and generic responses in the form of new knowledge concerning the mechanisms of recharge and groundwater - river exchanges, concerning the evolution of nitrate concentrations in watersheds, data and measurements for the parameterization of models, and water resources management tools in the form of quantitative and qualitative indicators for groundwater - surface water interactions. [less ▲]

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See detailHydrogeochemical mechanisms governing the mineralization and elevated fluoride (F -) contents in Precambrian crystalline aquifer groundwater in central Benin, Western Africa
Tossou, Yao Yelidji Joel ULiege; Orban, Philippe ULiege; Gesels, Julie et al

in Environmental Earth Sciences (2017), 76(20),

In the central part of Benin (Western Africa), high fluoride (F -) contents have been reported in groundwater from Precambrian crystalline bedrock aquifer which is the main source of drinking water. The ... [more ▼]

In the central part of Benin (Western Africa), high fluoride (F -) contents have been reported in groundwater from Precambrian crystalline bedrock aquifer which is the main source of drinking water. The hydrogeochemical mechanisms leading to such elevated fluoride concentrations are usually not fully understood. In this context, the objective is to identify the hydrogeochemical processes governing groundwater mineralization and the origin of the high fluoride concentrations. A dataset of 162 groundwater samples was collected from the aquifer consisting of a thin altered bedrock layer (shallow aquifer) and a deep fractured crystalline bedrock (deep aquifer). Geochemical approaches and multivariate statistics have been used to explore the data. Fluoride concentrations vary between 0.00 and 7.19 mg/L in groundwater. Samples collected in the southern part of the investigated area, close to Dassa-Zoumé, show the highest concentrations, with more than 75% greater than the guideline value of 1.5 mg/L. The deep fractured aquifer shows higher concentrations of fluoride than the shallow regolith reservoir. Results reveal that groundwater mineralization is derived mainly from the hydrolysis of silicate minerals, but it is also influenced by anthropogenic effects, particularly in the shallow reservoir. However, fluoride has a geogenic origin, primarily from the weathering of silicate minerals, primarily biotite. Ca 2 +/ Na + cation exchanges and F -/ OH - anion exchanges between groundwater and the rock matrix also occur as minor processes. Saturation of the water with respect to calcite and the precipitation of this mineral, which reduces calcium activity, also favor the release of fluoride from rocks. © 2017, Springer-Verlag GmbH Germany. [less ▲]