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Description of the Hermalle site

The Hermalle-sous-Argenteau test site is located around 13 km north-east of the city of Liège in Belgium. The test site consists of alluvial sediments (Wildemeersch et al., 2014). The first layer is composed of loam with clay lenses (1 to 1.5 m below land surface). The second layer is composed of a sandy loam with millimetric gravels which proportion increases with depth down to 3 m below land surface. And the third layer is composed of alluvial sand and gravel from 3 to 10 m below land surface. The ratio of gravel to sand of the latter layer increases progressively with depth. Six piezometers were drilled during the 1980s. The piezometers are distributed over the test site and are screened within the alluvial gravels. The long term monitoring of the hydraulic conditions showed that the average natural groundwater table is around 3.2 m below land surface, while annual variations of around 0.5 m were observed (Brouyère, 2001, 2003). The natural gradient is around 0.06 % and directed toward the north-east (Brouyère, 2001, 2003). In addition, the natural temperature of the aquifers varies between 13.34ºC (December) and 11.91ºC (June). Key values estimated from pumping and tracer tests are an average hydraulic conductivity of 2×10-2 m s-1 to 7×10-2 m s-1, a longitudinal dispersivity ranging between 0.5 m and 5 m and an effective porosity from 4% to 8% (Brouyère, 2001, 2003). More recent analyses have shown that heterogeneity (Hermans et al., 2015a) probably plays an important role in transport pathways (Hoffmann et al., 2019).  

Twelve new wells were drilled in 2012, which are closer to each other. Nine of these twelve recently drilled piezometers are double-screened with a 2 m lower screen level set at the bottom of the aquifer between 8 and 10 m depth and an upper screen level placed between 5 and 6 m depth (Wildemeersch et al., 2014). These are organized as three transverse control planes across the flow direction and bordered by two individual wells. These nine piezometers are located 17 m, 12 m and 5 m upgradient from a potential pumping well and thus, 3 m, 8 m and 15 m downgradient from a potential injection well (Wildemeersch et al., 2014). Recently several hydrogeological and geophysical tests were conducted in this part of the aquifer (e.g. heat-solute injection by Wildemeersch et al. (2014), ERT monitoring of a heat tracer by Hermans et al. (2015b), monitoring transient groundwater fluxes using the Finite Volume Point Dilution Method by Jamin & Brouyère (2018) or the heat storage experiment by Hermans et al. (2019) and Lesparre et al. (2019), and evaluated with different purposes (Hermans et al. 2015a,b, 2018, 2019; Hermans & Irving, 2017; Klepikova et al., 2016; Hoffmann et al., 2019; Lesparre et al., 2019). These tests investigated the heterogeneity patterns influencing the parameterization of the test site by developing and using new innovative methods that deal more realistic with spatial heterogeneity of such complex aquifers (e.g. methods based on Monte Carlo).  



  1. 1. S. Brouyère. Study and quantification of contaminant transport and capturing in variably saturated underground media. Quantification of hydrodispersive parameters using field tracer techniques. PhD thesis, University of Liege, 2001. [ http ]
  2. 2. S. Brouyère. Modeling tracer injection and well-aquifer interactions: A new mathematical and numerical approach. Water Resources Research, 39(3), 2003. [ DOI ]
  3. 3. T. Hermans and J. Irving. Facies discrimination with electrical resistivity tomography using a probabilistic methodology: effect of sensitivity and regularisation. Near Surface Geophysics, 15(1):13--25, 2017. [ DOI ]
  4. 4. T. Hermans, N. Lesparre, G. De Schepper, and T. Robert. Bayesian evidential learning: a field validation using push-pull tests. Hydrogeology Journal, pages 1661--1672, 2019. [ DOI ]
  5. 5. T. Hermans, F. Nguyen, and J. Caers. Uncertainty in training image-based inversion of hydraulic head data constrained to ERT data: Workflow and case study. Water Resources Research, 51(7):5332--5352, 2015a. [ DOI ]
  6. 6. T. Hermans, F. Nguyen, M. Klepikova, A. Dassargues, and J. Caers. Uncertainty quantification of medium-term heat storage from short-term geophysical experiments using Bayesian evidential learning. Water Resources Research, 54(4):2931--2948, 2018. [ DOI ]
  7. 7. T. Hermans, S. Wildemeersch, P. Jamin, P. Orban, S. Brouyère, A. Dassargues, and F. Nguyen. Quantitative temperature monitoring of a heat tracing experiment using cross-borehole ERT. Geothermics, 53:14--26, 2015b. [ DOI ]
  8. 8. R. Hoffmann, A. Dassargues, P. Goderniaux, and T. Hermans. Heterogeneity and prior uncertainty investigation using a joint heat and solute tracer experiment in alluvial sediments. Frontiers in Earth Science, 7:108, 2019. [ DOI ]
  9. 9. P. Jamin and S. Brouyère. Monitoring transient groundwater fluxes using the Finite Volume Point Dilution method. Journal of Contaminant Hydrology, 218:10--18, 2018. [ DOI ]
  10. 10. M. Klepikova, S. Wildemeersch, T. Hermans, P. Jamin, P. Orban, F. Nguyen, S. Brouyère, and A. Dassargues. Heat tracer test in an alluvial aquifer: Field experiment and inverse modelling. Journal of Hydrology, 540:812 -- 823, 2016. [ DOI ]
  11. 11. N. Lesparre, T. Robert, F. Nguyen, A. Boyle, and T. Hermans. 4D electrical resistivity tomography (ERT) for aquifer thermal energy storage monitoring. Geothermics, 77:368 -- 382, 2019. [ DOI ]
  12. 12. S. Wildemeersch, P. Jamin, P. Orban, T. Hermans, M. Klepikova, F. Nguyen, S. Brouyère, and A. Dassargues. Coupling heat and chemical tracer experiments for estimating heat transfer parameters in shallow alluvial aquifers. Journal of Contaminant Hydrology, 169:90 -- 99, 2014. [ DOI ]


Data Available At The Hermalle Site


Access to the data from Google Earth module

The Google Earth module provides a site visualization and information on data available such as types of measurements, locations, dates, etc. This interface also provides an overview of geophysical maps and cross-sections, which can be directly downloaded from the available links. Data available through predefined requests can be downloaded from this interface too.  

To download the Google Earth file and access to the data of this site, click on the following icon


Access to the data from database interface

All data inserted in the H+ database can be extracted using requests, which can be defined through this interface. For more information, please read the tutorial available here.


Overview of the database interface.


Access to the data from predefined requests

To help finding general data sets, predefined requests have been created and are regularly executed. Results can be downloaded from the links available below.




Site data

Spatialized data


Experimental bench


In situ measurements



Soil atmosphere exchange