Category Archives: Non classé

EGU meeting: about the non-linear interactions in a karst system

Hydrological connectivity from causal analysis of time series in the Lhomme Karst System, Belgium.
Damien Delforge, Michel Van Camp, Marnik Vanclooster, Vincent Hallet, Olivier Kaufmann, Amaël Poulain, and Arnaud Watlet

EGU meeting, Vienna, April 8, 2019

The hydrological behaviour of karstic systems is difficult to theorize holistically because of their specific heterogeneities leading to distinctive non-linear processes. Karstified systems present great opportunities for field exploration and hydrogeological monitoring of the vadose zone through its network of caves and conduits. These unique but explorable environments are predisposed to an inductive scientific approach where transfer processes associated with hydrological connections are directly inferred from the data. This is done conventionally using dye tracing from which connections and transfer times are undeniably revealed. However, single tests do not allow appreciating the dynamic character of the hydrological connections. Nowadays,several data analysis methods aim at the detection of causal relationships between time series allowing the investigation of dynamics and interactions. Some are designed for linear systems as the simple cross-correlation method or the Granger causality, while others are suitable for non-linear interactions, such as the Convergent Cross Mapping method. Here, these methods are applied in order to draw up causal maps and compare short-term (up to 2 days) interactions in the Lhomme Karst System in Belgium. The Lhomme Karst System has been monitored since 2013 and many time series are available: meteorological data, soil moisture, drip discharges in the caves, piezometric levels, and local gravimetric time series. In addition, dye tracing experiments revealing connections and characteristic transfer times were conducted. The different causal maps are compared and causal interactions are appreciated through the current knowledge of the system and discussed in relation to the question: can we infer true hydrological connections and processes from the empirical determination of causal relationships between hydrological time series?

9 November: PhD thesis of Arnaud Watlet

On 9 November 2017, Arnaud Watlet will defend his PhD thesis dedicated to the de FNRS KARAG project of Rochefort.
Arnaud will present 4 years of results on the saturated and non-saturated zones of the karst aquifers.
The jury will be composed of the following members:
Prof. Olivier Kaufman, Université de Mons
Dr. Michel Van Camp, Observatoire Royal de Belgique
Pr Jean-Marc Baele, Université de Mons
Pr Thierry Camelbeeck, Observatoire Royal de Belgique
Pr Konstantinos Chalikakis, Université d’Avignon
Pr Cédric Champollion, Université de Montpellier
Pr Olivier Francis, Université de Luxembourg
Pr Pascal Goderniaux, Université de Mons
The dissertation defense will take place at 15 pm at U. Mons, Salle Académique, Bd Dolez, 31 (2e étage), 7000 Mons. The defense is public.
Aucun texte alternatif disponible.

Rochefort Cave lab on TV

The underground work of the KARAG team was presented on Belgium national televion (La Une) 28th of September at 12:40 PM! The small documentary focuses on the Rochefort cave laboratory and the measurements made in the vadose zone of the Givetian karst aquifer (click on the picture to watch the video).

Don’t miss this opportunity to discover our work 😉



A first PhD for KARAG

Amaël Poulain presented his PhD thesis last week, in the framework of the KARAG project.

Follow this link to see the Prezi presentation :

The thesis file may be downloaded at the following URL :

Remember that Arnaud Watlet will also present his PhD thesis in Geophysics this year. Stay tuned for more information !


Phd thesis defense

On the 6th of September 2017, Amaël Poulain will present his PhD thesis in the framework of the KARAG project. He will present 4 years of research about phreatic and vadose zones hydrogeology in karst aquifers and specifically a focus on the Lomme Karst System in Rochefort.

The thesis jury :

  • Prof. Vincent Hallet (University oy Namur – Promoter)
  • Prof. Johan Yans (University of Namur – President)
  • Prof. Olivier Kaufmann (University of Mons)
  • Prof. Marnik Vanclooster (Catholic University of Louvain)
  • Prof. Pascal Goderniaux (University of Mons)
  • Prof. Hervé Jourde (University of Montpellier – France)

The defense will start at 4PM in the M01 room (Faculty of Medicine – University of Namur). Access via Place du Palais de justice (lien Street View)

Abstract in french

The defense is public