Poster Année : 2025

Modeling the influence of the vadose zone in a geophysical study of the ORGEVAL critical zone observatory

Résumé

Quantifying the water and heat fluxes at the interface between surface and groundwater (GW) including the vadose zone (VZ), surface water (SW) and GW interfaces is a key issue for water and energy resource management. This is because it ensures a safe yield and good water quality under the ongoing global change. Such quantification with field measurements is not straightforward because the SW-GW changes depend on the boundary conditions and the spatial description of the hydrofacies. These are not well known and are usually estimated by calibrating models using classical data like hydraulic heads and river discharge. To overcome the lack of direct in situ data, de Marsily et al., 2005 advice to couple the classical observation with unconventional data such as the geophysical surveys (Binley et al., 2015). This study provides new insight about the use of the geophysical methods, such as heat as a tracer, electrical resistivity tomography (ERT) and seismic monitoring to characterize the VZ functionning. We develop a methodology to build stronger constraints to the inversion methods to estimate the hydrodynamic and thermal parameter and the boundary conditions, both in space and time, by using a multi-method approach. The hydrogeological forward model Ginette (Rivière et al., 2016), based on the Richards equation and the heat transport. This forward model is used to study variability saturated flow and the heat fluxes in 1D heterogeneous soil subject to seasonal variation in precipitation and temperature. The sensitivity of geophysical data on the VZ parameters is estimated by using synthetic cases and the SantiLudo model. The SantiLudo model (Solazzi et al., 2021) is founded on the Hertz-Mindlin contact theory combined with the Biot-Gassmann model and the influence of capillary succion. This model is used to obtain the mechenical hence siesmic properties of a soil in relation to its degree of saturation. The synthetic case study developed, that mimics the VZ of the Orgeval critical zone observatory (France) influenced by temperate climatic conditions and hydrological forcings, considers the hydaulic and thermal parameters of various porous media representative of a wide range of hydrofacies.

Fichier non déposé

Dates et versions

hal-05415923 , version 1 (15-12-2025)

Identifiants

  • HAL Id : hal-05415923 , version 1

Citer

Nicolas Radic, Agnès Rivière, Alexandrine Gesret, Ludovic Bodet, Sylvain Pasquet, et al.. Modeling the influence of the vadose zone in a geophysical study of the ORGEVAL critical zone observatory. 3rd OZCAR TERENO Conference, Sep 2025, PARIS, France. ⟨hal-05415923⟩
81 Consultations
0 Téléchargements

Partager

  • More