References of "Brouyère, Serge"
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See detailMONitOring des flux de POLluants dans les Eaux Souterraines
Jamin, Pierre ULg; Dassargues, Alain ULg; Brouyère, Serge ULg

Poster (2017, May 05)

Contaminated aquifers management is currently based on the evaluation of pollutant concentration in the groundwater. This approach is necessary but totally insufficient to evaluate the risk posed by the ... [more ▼]

Contaminated aquifers management is currently based on the evaluation of pollutant concentration in the groundwater. This approach is necessary but totally insufficient to evaluate the risk posed by the contamination to potential receptors. Since the risk is due to the pollutant that are actually moving, and might reach a receptor, this concentration measurement should be combined to a measurement of the groundwater flow velocity (i.e. the driving force of contaminant migration in aquifers), to quantify the contaminant mass flux at which the receptor is exposed. We propose a new point dilution technique able to measure accurately the groundwater flux and to monitor continuously its changes with time. [less ▲]

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See detailOccurrence of greenhouse gases (CO2, N2O and CH4) in groundwater of the Walloon Region (Belgium).
Jurado Elices, Anna ULg; Borges, Alberto ULg; Pujades, Estanislao ULg et al

Conference (2017, April 28)

Greenhouse gases (GHGs) are an environmental problem because their concentrations in the atmosphere have continuously risen since the industrial revolution. They can be indirectly transferred to the ... [more ▼]

Greenhouse gases (GHGs) are an environmental problem because their concentrations in the atmosphere have continuously risen since the industrial revolution. They can be indirectly transferred to the atmosphere through groundwater discharge into surface water bodies such as rivers. However, their occurrence is poorly evaluated in groundwater. The aim of this work is to identify the hydrogeological contexts (e.g., chalk and limestone aquifers) and the most conductive conditions for the generation of GHGs in groundwater at a regional scale. To this end, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) concentrations, major and minor elements and environmental isotopes were monitored in several groundwater bodies of the Walloon Region (Belgium) from September 2014 to June 2016. The concentrations of GHGs in groundwater ranged from 1769 to 100519 ppm for the partial pressure of CO2 and from 0 to 1064 nmol/L and 1 to 37062 nmol/L for CH4 and N2O respectively. Over- all, groundwater was supersaturated in GHGs with respect to atmospheric equilibrium, suggesting that groundwater contribute to the atmospheric GHGs budget. Prior inspection of the data suggested that N2O in groundwater can be produced by denitrification and nitrification. The most suitable conditions for the accumulation of N2O are promoted by intermediate dissolved oxygen concentrations (2.5-3 mg L−1) and the availability of nitrate (NO3 ). These observations will be compared with the isotopes of NO3 . CH4 was less detected and at lower concentration than N2O, suggesting that groundwater redox conditions are not reducing enough to promoted the production of CH4. The results will be presented and discussed in detail in the presentation. [less ▲]

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See detailWater chemical evolution in Underground Pumped Storage Hydropower plants and induced consequences.
Pujades, Estanislao ULg; Orban, Philippe ULg; Jurado Elices, Anna ULg 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 detailFactors controlling the evolution of groundwater dynamics and chemistry in the Senegal River Delta
Gning, Abdoul Aziz; Orban, Philippe ULg; Gesels, Julie ULg 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 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 ULg; Pujades, Estanislao ULg; Orban, Philippe ULg 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 ULg; Dollé, Fabien ULg; Orban, Philippe ULg 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 detailDynamics and emissions of N2O in groundwater: A review
Jurado Elices, Anna ULg; Borges, Alberto ULg; Brouyère, Serge ULg

in Science of the Total Environment (2017), 584-585C

This work reviews the concentrations, the dynamics and the emissions of nitrous oxide (N2O) in groundwater. N2O is an important greenhouse gas (GHG) and the primary stratospheric ozone depleting substance ... [more ▼]

This work reviews the concentrations, the dynamics and the emissions of nitrous oxide (N2O) in groundwater. N2O is an important greenhouse gas (GHG) and the primary stratospheric ozone depleting substance. The major anthropogenic source that contributes to N2O generation in aquifers is agriculture because the use of fertilizers has led to the widespread groundwater contamination by inorganic nitrogen (N) (mainly nitrate, NO3−). Once in the aquifer, this inorganic N is transported and affected by several geochemical processes that produce and consume N2O. An inventory of dissolved N2O concentrations is presented and the highest dissolved concentration is about 18.000 times higher than air-equilibrated water (up to 4004 μg N L-1). The accumulation of N2O in groundwater is mainly due to denitrification and to lesser extent to nitrification. Their occurrence depend on the geochemical (e.g., NO3−, dissolved oxygen, ammonium and dissolved organic carbon) as well as hydrogeological parameters (e.g., groundwater table fluctuations and aquifer permeability). The coupled understanding of both parameters is necessary to gain insight on the dynamics and the emissions of N2O in groundwater. Overall, groundwater indirect N2O emissions seem to be a minor component of N2O emissions to the atmosphere. Further research might be devoted to evaluate the groundwater contribution to the indirect emissions of N2O because this will help to better constraint the N2O global budget and, consequently, the N budget. [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 ULg; Briers, Pierre ULg; 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 detailPROPOSITION D'UN SUPPORT D'AIDE À LA DÉCISION POUR L'AMÉLIORATION DE L'ACCÈS À UNE EAU SOUTERRAINE DE MEILLEURE QUALITÉ DANS UN CONTEXTE DE CONTAMINATION GÉOGÉNIQUE AU FLUORURE AU BENIN (AFRIQUE DE L'OUEST)
Tossou, Joël; Hermans, Thomas ULg; Orban, Philippe ULg et al

in Geo-Eco-Trop : Revue Internationale de Géologie, de Géographie et d'Ecologie Tropicales (2017)

Les eaux souterraines des aquifères de socle cristallin de la partie centrale du Bénin (Département des Collines) présentent des concentrations élevées en fluorure, allant jusqu'à 7 mg/L alors que la ... [more ▼]

Les eaux souterraines des aquifères de socle cristallin de la partie centrale du Bénin (Département des Collines) présentent des concentrations élevées en fluorure, allant jusqu'à 7 mg/L alors que la norme recommandée par l'OMS est de 1.5 mg/L. La consommation de ces eaux à fortes teneurs en fluorure impacte la santé humaine. La population de la région est effectivement largement affectée par la fluorose dentaire. Les investigations hydrogéochimiques révèlent que l’origine de ces teneurs anormales est géogénique avec une forte contribution des minéraux ferromagnésiens, principalement la biotite. Ce travail se propose de réaliser une double cartographie à l'échelle du département des Collines: (i) une carte de l'estimation des teneurs en fluorure dans les eaux souterraines par krigeage ordinaire et (ii) une carte de la probabilité d'excéder la valeur guide de l’OMS (1.5 mg/L) en fluorure dans les eaux par krigeage d'indicatrices. Outre la cartographie en elle-même, l'analyse de la structure spatiale des données (teneurs en fluorure des eaux souterraines) à travers le calcul des variogrammes montre qu'il existe un lien fort entre celles-ci et les structures géologiques dominantes, confirmant l'origine géogénique du fluorure. Ces informations cartographiques serviront de support à la décision pour les décideurs et les gestionnaires de la ressource quant au choix judicieux des zones de captage d'eau potable pour minimiser/éviter les risques de fortes teneurs en fluorure. [less ▲]

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See detailFactors controlling spatial and temporal patterns of multiple pesticide compounds in groundwater (Hesbaye chalk aquifer, Belgium)
Hakoun, Vivien; Orban, Philippe ULg; Dassargues, Alain ULg et al

in Environmental Pollution (2017)

Factors governing spatial and temporal patterns of pesticide compounds (pesticides and metabolites) concentrations in chalk aquifers remain unclear due to complex flow processes and multiple sources. To ... [more ▼]

Factors governing spatial and temporal patterns of pesticide compounds (pesticides and metabolites) concentrations in chalk aquifers remain unclear due to complex flow processes and multiple sources. To uncover which factors govern pesticide compound concentrations in a chalk aquifer, we develop a methodology based on time series analyses, uni- and multivariate statistics accounting for concentrations below detection limits. The methodology is applied to long records (1996–2013) of a restricted compound (bentazone), three banned compounds (atrazine, diuron and simazine) and two metabolites (deethylatrazine (DEA) and 2,6–dichlorobenzamide (BAM)) sampled in the Hesbaye chalk aquifer in Belgium. In the confined area, all compounds had non-detects fractions >80%. By contrast, maximum concentrations exceeded EU’s drinking-water standard (100 ngL-1) in the unconfined area. This contrast confirms that recent recharge and polluted water did not reach the confined area, yet. Multivariate analyses based on variables representative of the hydrogeological setting revealed higher diuron and simazine concentrations in the southeast of the unconfined area, where urban activities dominate land use and where the aquifer lacks protection from a less permeable layer of hardened chalk. At individual sites, positive correlations (up to τ =0,48 for bentazone) between pesticide compound concentrations and multi-annual groundwater level fluctuations confirm occurrences of remobilization. A downward temporal trend of atrazine concentrations likely reflects decreasing use of this compound over the last 28 years. However, the lack of a break in concentrations time series and maximum concentrations of atrazine, simazine, DEA and BAM exceeding EU’s standard post-ban years provide evidence of persistence. Contrasting upward trends in bentazone concentrations show that a time lag is required for restriction measures to be efficient. These results shed light on factors governing pesticide compound concentrations in chalk aquifers. The developed methodology is not restricted to chalk aquifers, it could be transposed to study other pollutants with concentrations below detection limits. Several factors govern pesticide compounds concentrations in the chalk: hydrogeological setting, land use, groundwater level fluctuations and persistence. [less ▲]

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See detailStream-aquifer interactions: a combined field - methodological approach in fractured carbonate catchments
Brouyère, Serge ULg; Briers, Pierre ULg; Orban, Philippe ULg et al

Conference (2016, December 16)

Stream-aquifer studies remain a challenge due to numerous factors impacting these interactions. They play a fundamental role in terms of quantity and quality of water, in particular on the ecological ... [more ▼]

Stream-aquifer studies remain a challenge due to numerous factors impacting these interactions. They play a fundamental role in terms of quantity and quality of water, in particular on the ecological status of rivers. Field quantification of such interactions is a first step but it has to be in relation with the whole budgets of water and transported substances across the catchment in order to represent their importance on overall fluxes. Numerous complementary investigations have to be undertaken to achieve such understanding of catchment behavior, in particular to estimate specific indicators and to achieve representative data for modeling stream-aquifer interactions. From that situation, our study aims to characterize and quantify stream-aquifer interactions to assess reliability of diverse field experiments methodologies. A catchment has been studied for 3 years in quantitative and qualitative ways via a dense instrumentation and monitoring. Numerous complementary investigations (discharge measurements, hydrogeochemistry, distributed temperature sensing, base flow separation…) have been applied to reach the objectives. We achieved a large and diversified measurement dataset of groundwater-surface water interactions and whole water budget. This allowed reaching an improved understanding of the catchment behavior to quantify importance of the groundwater component on the dynamics and chemistry of the stream and on the consequences on river ecological status. The investigations on several subcatchments allows also to propose a general typology of stream catchment in terms of groundwater dependence based on the combination of various groundwater contexts and groundwater-stream interaction indicators. Methodologies applied in this study allow to emphasize strength and weakness of numerous investigations in a stream aquifer project and conclusions can be reproduced and generalized to other contexts. [less ▲]

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See detailAn old slate mine as lower reservoir for UPSH (Underground Pumping Storage Hydroelectricity)- groundwater interactions and limitations
Bodeux, Sarah ULg; Pujades, Estanislao ULg; Orban, Philippe ULg et al

Conference (2016, September 27)

Renewable energy sources have an increasing role to play in the future energy framework but their intermittence cannot afford a stable production according to the demand. Pumped Storage Hydroelectricity ... [more ▼]

Renewable energy sources have an increasing role to play in the future energy framework but their intermittence cannot afford a stable production according to the demand. Pumped Storage Hydroelectricity (PSH) is an efficient technology to store and release electricity. However, the development of new PSH plants is limited by environmental and topographic constraints. An innovative alternative consists in using old underground mines as lower reservoirs of Underground Pumped Storage Hydroelectricity (UPSH) plants. In this configuration, large amount of water is pumped and injected in underground cavities and these cyclic stresses impact the groundwater system. A hybrid 3D finite element mixing cell method is used to numerically simulate the use of an UPSH facility, in the case of an abandoned slate mine. Different scenarios are computed with varying pumping injection time-sequences. In order to assess the impact on the surrounding groundwater conditions, the resulting head evolution in the cavity and at different distances is analyzed in terms of groundwater oscillation magnitude, drawdown, and seepage into the cavity. Results show clearly the influence of the pumping injection time-sequence (rates, regularity, timing and duration of no-activity periods) on the actual head evolution in the surrounding medium and consequently on the magnitude of interactions with the cavity. For a given hydraulic conductivity of the surrounding medium (i.e. slates in this case study), the main conclusion is that the resulting interaction seepage flows (in and out of the cavity) are highly dependent on the chosen pumping injection sequences. The future impact of UPSH operation must be assessed taking this fact into account. [less ▲]

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See detailOccurrence of greenhouse gases (CO2, N2O and CH4) in groundwater of the Walloon Region (Belgium)
Jurado Elices, Anna ULg; Borges, Alberto ULg; Hakoun, Vivien et al

Conference (2016, September 27)

Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) can be indirectly transferred to the atmosphere through groundwater discharge into surface water bodies such as rivers. However, these emissions ... [more ▼]

Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) can be indirectly transferred to the atmosphere through groundwater discharge into surface water bodies such as rivers. However, these emissions are poorly evaluated and highly uncertain. The aim of this work is identify the hydrogeological contexts (alluvial, sandstone, chalk and limestone aquifers) and in situ conditions which are most conducive to the generation and occurrence of GHGs in groundwater at a regional scale. To this end, CO2, CH4 and N2O concentrations as well as major and minor elements were monitored (n=37 samples) in two field campaigns (09/2014 and 03/2015) in 15 groundwater bodies of the Walloon Region (Belgium). This preliminary work, which was presented in the 42st IAH conference (Rome, Italy), shown that GHG concentrations range from 5,160 to 47,544 ppm from the partial pressure of CO2 and from 0 to 1,064 nmol/L and 1 to 5,637 nmol/L for CH4 and N2O respectively. Overall, groundwater was supersaturated in GHGs with respect to atmospheric equilibrium, suggesting that groundwater contribute to the atmospheric GHGs budget. A third sampling campaign is carried out in 2016 including around 60 new groundwater samples. The combination of the results of the three campaigns allows: (1) reducing the uncertainties related to indirect emissions of GHG through groundwater-surface water interaction and (2) contributing to a better understanding of the occurrence of GHGs in aquifers. New results will be presented and discussed in detail in the presentation. [less ▲]

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See detailComparison of temperature from DTS and ERT with direct measurements during heat tracer experiments in heterogeneous aquifers
Nguyen, Frédéric ULg; Hermans, Thomas ULg; Jamin, Pierre ULg et al

Conference (2016, September 27)

Geothermal field characterization and heat tracer experiments often rely on scarce temperature data collected in boreholes. Electrical resistivity tomography (ERT) and distributed temperature sensing (DTS ... [more ▼]

Geothermal field characterization and heat tracer experiments often rely on scarce temperature data collected in boreholes. Electrical resistivity tomography (ERT) and distributed temperature sensing (DTS) have the potential to provide spatial information on temperature changes in the subsurface. In this contribution, we show how DTS and ERT have been used to investigate the heterogeneity of a heterogeneous aquifer during a heat tracing experiment under forced gradient conditions. Optic fibers were installed in the heat injection well and in two piezometers intersecting the main flow directions at 8 m from the injection well. These piezometers were also equipped with ERT. The DTS measurement in the injection well clearly shows the two-layer nature of the aquifer. After the end of injection, the temperature in the bottom part of the well decreases faster than in the upper part due to the higher water fluxes. Those results are confirmed by DTS measurements in natural flow conditions during a heating wire test. DTS and ERT in the cross-panel both show the vertical and lateral heterogeneity of the aquifer. Temperatures only increase significantly in the bottom part of the aquifer where advection is predominant. However, strong differences are observed laterally. ERT additionally shows that the hot plume is divided in two main flow paths, which is confirmed by direct temperature measurements. The comparison of DTS and ERT shows that one of the well is suffering from water mixing. Indeed, temperature from DTS are homogeneous over the whole tichkness of the aquifer, whereas ERT temperature, less affected by local variations, are varying. Our study demonstrate the value of spatially distributed measurements for the monitoring of heat tracer experiment and highligths the issue of multilevel sampling. The detailed temperature measurements can be subsequently used in hydrogeological model to better estimates heat flow and transport parameters. [less ▲]

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See detailHow groundwater interactions can influence UPSH (Underground Pumping Storage Hydroelectricity) operations
Bodeux, Sarah ULg; Pujades, Estanislao ULg; Orban, Philippe ULg et al

Conference (2016, July 28)

In the current energy grid, renewable energy has an increasing role to play. However, their intermittence cannot afford to regulate the produced electricity according to the irregular demand (Evans et al ... [more ▼]

In the current energy grid, renewable energy has an increasing role to play. However, their intermittence cannot afford to regulate the produced electricity according to the irregular demand (Evans et al., 2012). Pumped Storage Hydroelectricity (PSH) is a well-known efficient technology to store and release electricity according to the demand needs but appropriate potential new sites are getting scarce (Steffen, 2012). An innovative alternative consists in using abandoned mines as lower reservoir of an Underground Pumping Storage Hydroelectricity (UPSH) plant. In such configuration, large amount of water will be pumped or injected in underground cavities, creating subsequently head oscillations in the surrounding aquifers. Consequently, this seepage occurring between the considered cavity and the varying groundwater heads in the surrounding geological medium may influence the efficiency of the UPSH plant but also the magnitude of the potential impacts on the groundwater resources. A hybrid 3D finite element mixing cell method (Brouyère et al., 2009) is used to simulate numerically the use of a representative UPSH cavity and calculate the induced changes in groundwater heads in the surrounding geological medium. Different scenarios are computed varying parameter values (hydrogeological and lower reservoir characteristics), boundary conditions, and pumping/injection time-sequences. By analyzing the computed piezometric heads at different distances from the underground reservoir, the magnitude of the aquifer response to pumping storage operations is assessed. The most expected and noticeable effect is the oscillation of groundwater levels. The existence a mean pseudo/ dynamic steady-state and the required time to reach it are also determined. The head difference and its time evolution between the cavity and the surrounding medium is triggering the leakage of groundwater into the cavity or the contrary. The resulting effects on the UPSH plant efficiency can be estimated. Combining these outcomes, some feasibility criteria of this type of projects are identified. Going into practice, further models should include more in de-tails local and specific geometrical and hydrogeolog-ical data of the considered old mine cavities used as lower reservoir. This kind of modelling approach can be used as a first approach for determining how the aquifer will response to short and long term changes in UPSH pumping/injection schemes. [less ▲]

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See detailGroundwater flow and transport modelling at regional scale: lessons learned from different applications in the Walloon Meuse basin
Dassargues, Alain ULg; Goderniaux, Pascal; Orban, Philippe ULg et al

Conference (2016, July 28)

An overview is proposed of the recent groundwater modelling works, at the groundwater body scale, performed by the Hydrogeology & Environmental Geology team of the University of Liège. The developed ... [more ▼]

An overview is proposed of the recent groundwater modelling works, at the groundwater body scale, performed by the Hydrogeology & Environmental Geology team of the University of Liège. The developed modelling tools are built in the general objective of improving our understanding and management, at short, middle and long terms, of the groundwater bodies. The general strategy to be followed implies that conceptualization, parameterization and calibration must be adapted to the actual objectives of each model (Wildemeersch et al., 2014). 3 specific applications are illustrated involving two main groundwater bodies: - application of the HFEMC method (Wildemeersch et al., 2010) within the SUFT3D code for groundwater flow modelling of the ‘Synclinorium of Dinant’ (Orban et al., 2010 and Brouyère et al., 2011); - application of the HFEMC method and the SUFT3D code for the nitrate trends (Batlle-Aguilar et al., 2007) simulations in the Geer basin (Orban et al., 2010) for different scenarios of nitrate inputs; - application of the HGS integrated model for assessing the impact of climate change on the groundwater reserves in the Geer basin (Brouyère et al., 2004, Goderniaux et al., 2009 and 2011) with quantification and comparison of the different uncertainty sources (Goderniaux et al., 2015) Lessons and perspectives are learned and proposed from these modelling experiences at the scale of the groundwater body. [less ▲]

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