PS-InSAR data, key to understanding and quantifying the hydromechanical processes underlying the compaction of aquifer systems. Case of West- and East-Flanders, Belgium

Abstract

Until the advent of remote sensing techniques, the study of regional subsidence was hampered by the rarity and sparsity of field measurements of ground displacement, which led to a significant uncertainty regarding the representativeness of the calibration data used in the modelling of these phenomena and the reliability of derived predictions. This paper explores the unique potential of Persistent Scatterer Interferometry with Synthetic Aperture Radar (PS-InSAR) in the hydromechanical modelling of a large-scale, long-term subsidence occurring in the provinces of West- and East-Flanders, Belgium, related to the overexploitation of the deep aquifer system in the region. PS-InSAR has been used, not only to describe and characterise the ground subsidence and identify representative locations, but also to calibrate the hydromechanical parameters of the ground and validate the results of a numerical model. PS-InSAR has proven to be essential to improve the calibration and reach a set of parameters (i) coherent with the hydrogeology of the study area, (ii) coherent between different deforming zones and (iii) able to reproduce the dynamics of the observed ground subsidence. Thus, PS-InSAR enables to accurately reproduce, understand and simulate the compaction of an aquifer system and, ultimately, design adequate and optimised management policies.