Field deployment and analysis of hydraulic tomography experiments with periodic slug tests in an anisotropic littoral aquifer
Résumé
Accurate mapping of the heterogeneity of hydraulic properties, including hydraulic conductivity (Kh) and its anisotropy (Kv/Kh), is crucial for predicting groundwater flow and solute transport in aquifers. This study investigates the use of hydraulic tomography with periodic signals to map Kh, Kv/Kh and specific storage (Ss) in an unconsolidated littoral aquifer. The periodic signals were generated by the movement of a rod numerically controlled by a winch, which allowed the signal amplitude and period to be imposed. Thirty periodic slug tests with periods of 150, 300 and 600 s were conducted between isolated intervals in a source well and an observation well, generating 120 head responses. Numerical inversion in the time domain used the rod-induced flow rates and associated heads to estimate the heterogeneous fields. Significant differences in head amplitude and phase shift between test intervals at different locations highlighted the heterogeneity of the aquifer. The inversion results for single and combined periods are consistent with the values of previous studies and the heterogeneous nature of the littoral aquifer. Comparison of models from different periods revealed slight spatial and statistical variations in hydraulic properties and different hydraulic behavior when tested with independent hydraulic tests. While the fundamentals of understanding the information in the different periodic signals need to be further clarified, this study advances the application of hydraulic tomography under real field conditions and highlights its effectiveness in characterizing aquifer heterogeneity and anisotropy.
Origine | Fichiers produits par l'(les) auteur(s) |
---|