Characterizing aquifer properties through a sparse-grids-based Bayesian framework and
InSAR measurements: A basin-scale application to Alto Guadalentin, Spain
Y. Li, C. Zoccarato, P. Teatini
Dept. of Civil, Environmental and Architectural Engineering,
University of Padova, Padova, Italy
C. Piazzola
Dept. of Mathematics, Technical University of Munich, Germany
L. Tamellini
Consiglio Nazionale delle Ricerche, Istituto di Matematica Applicata e Tecnologie Informatiche (CNR-IMATI), Pavia, Italy
G. Bru, C. Guardiola-Albert
Geohazards InSAR Laboratory and Modeling Group (InSARlab), Geological and Mining Institute of Spain (IGME), CSIC, Madrid, Spain
Aquifer characterization is essential for predicting aquifer responses and ensuring sustainable
groundwater management. In this study we develop a sparse-grids-based Bayesian framework to infer the
hydraulic conductivity and the soil compressibility of over-exploited aquifer systems using Interferometric
Synthetic Aperture Radar (InSAR) ground displacement data sets and piezometric records. The framework
integrates a three-dimensional (3D) coupled variably saturated poromechanical model, accounting for the
complex interplay between groundwater depletion and soil deformation through the explicit quantification of
the porosity change. The Bayesian inversion approach enables a probabilistic characterization of parameters in
the form of a posterior distribution. However, exploring this posterior using Markov chain Monte Carlo
(MCMC) methods is computationally prohibitive due to the substantial cost of solving the nonlinear
poromechanical forward problem. To overcome this issue, we propose the use of sparse-grid surrogate models
to approximate the forward solutions. The methodology is applied to the Alto Guadalentin Basin, Spain, where
long-term aquifer exploitation has led to a lowering of the water table larger than 100 m causing impressive land
subsidence, with rates up to 15 cm/yr as evidenced by InSAR. The results demonstrate that integrating InSAR
data significantly enhances the characterization of the aquifer properties, with the resulting numerical
simulations aligning well with available observations.
