Hydraulic and transport parameter assessment using column infiltration experiments
A. Younes1,2,3, T. A. Mara4, M. Fahs1, O. Grunenberger2, and Ph. Ackerer11HyGES, Université de Strasbourg/EOST, CNRS, 1 rue Blessig, 67084 Strasbourg, France 2IRD UMR LISAH, F-92761 Montpellier, France 3LMHE, Ecole Nationale d’Ingénieurs de Tunis, Tunisie 4Université de La Réunion, PIMENT, 15 Avenue René Cassin, BP 7151, 97715 Moufia, La Réunion
Received: 10 Jun 2016 – Accepted for review: 11 Jun 2016 – Discussion started: 20 Jun 2016
Abstract. In the present work, we study the quality of the statistical calibration of hydraulic and transport soil properties using an infiltration experiment in which, over a given period, tracer-contaminated water is injected into a laboratory column filled with a homogeneous soil. The numerical model is based on the Richards' equation for solving water flow and the advection-dispersion equation for solving solute transport. Several state variables (e.g., water content, solute concentration, pressure head) are measured during the experiment. Statistical calibration of the computer model is then carried out for different data sets and injection scenarios with the DREAM(ZS) Markov Chain Monte Carlo sampler. The results show that the injection period has a significant effect on the quality of the estimation, in particular, the posterior uncertainty range. The hydraulic and transport parameters of the investigated soil can be estimated from the infiltration experiment using the concentration and cumulative outflow, which are measured non-intrusively. A significant improvement of the identifiability of the parameters is observed when the pressure data from measurements taken inside the column are also considered in the inversion.
Younes, A., Mara, T. A., Fahs, M., Grunenberger, O., and Ackerer, Ph.: Hydraulic and transport parameter assessment using column infiltration experiments, Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-295, in review, 2016.