Hydrogeology modeling of karstic aquifers associated to sub-marine springs while integrating recharge changes

Water resources management is a major societal issue highlighted by the current climate change. Karst aquifers represent significant freshwater reserves in different regions of the world, but their exploitation is complicated by their complex behaviour. Characterizing and modeling this type of aquifer requires studying three interacting levels of heterogeneity, the matrix medium (the rock), the fracture network and the open spaces of the karst system. The standard single or double-medium approaches based on homogenization and on a Darcy-type flow model do not allow to consider the triple media aspect and assume a Darcy-type flow in the karst conduits. However, the dimensions of these conduits can induce inertial flows that must be taken into account.
The work of the Ph.D. student will consist in developing a statistical model for the generation of the karst network, and then in correctly representing through an embedded model the three interacting media with a fine 3D discretization of the karst network and the fracture network. The flow resolution will be based on an inertial flow model in the karst conduits that can also handle density stratified flow to allow the modelling of a salt water wedge. The aquifer of the Causse d'Aumelas will provide an integrating case study for the development of this approach that will eventually allow a distributed triple-medium modeling of this aquifer hydrodynamics and of the flows at its various outlets.

Keywords: Aquifers, Karsts, Modeling, triple-medium

• Academic supervisor    Dr, JOURDE Hervé, HydroSciences Montpellier , 0000-0001-7124-4879. Dr, DELAY Frederick, Laboratoire d'HYdrologie et de GEochimie de Strasbourg
• Doctoral School    ED584 GAIA, https://gaia.umontpellier.fr/ 
• IFPEN supervisor    Dr, FOURNO André, Sciences de la Terre et Technologies de l’Environnement, andre.fourno@ifpen.fr, 0000-0002-9206-8111
• PhD location    IFP Energies nouvelles, Rueil-Malmaison, France   
• Duration and start date    3 years, starting in fourth quarter 2022
• Employer    IFP Energies nouvelles, Rueil-Malmaison, France 
• Academic requirements    University Master degree in Geology, Hydrogeology
• Language requirements    Fluency in French or English, willingness to learn French
• Other requirements    Programming