2D-ERT monitoring of soil moisture seasonal behaviour in a river levee: A case study

Clara Jodry (1, 2) , Sergio Palma Lopes (3) , Yannick Fargier (4) , Martin Sanchez (5) , Philippe Cote (6)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 Milieux Poreux - UMR7327
3 IFSTTAR/GERS/GeoEND - Laboratoire Géophysique et évaluation non destructive
4 IFSTTAR/GERS/RRO - Risque Rocheux et Ouvrages géotechniques
5 LPG - Laboratoire de Planétologie et Géodynamique [UMR 6112]
6 IFSTTAR/GERS - Département Géotechnique, Environnement, Risques naturels et Sciences de la terre

We present a study of the seasonal behaviour of soil moisture in an old embankment levee by means of 2D DC-electrical resistivity tomography monitoring based on an embedded electrode installation. We were able to produce seasonal resistivity change models that are compensated for temperature effects using a seasonal temperature profile model. Time-lapse sections of percentage resistivity changes show spatial and temporal overall consistency with seasonal variations of soil temperature. Discrepancies are likely due to the pavement layer that is not well considered in the inversion process as well as to time-lapse inversion pitfalls. Furthermore, a detailed estimation of seasonal moisture content variations could not be given as an accurate calibration of the employed suction probes was not achievable. Nevertheless, the levee appears to have spatially consistent time variations in soil moisture, clearly influenced by both rainfall and water table and river levels. Future work on developing 3D acquisitions and adding embedded moisture content probes should prove effective to our monitoring design and give a more detailed understanding of the soil moisture seasonal behaviour in the studied stretch of levee.

Mots clés: Electrical Resistivity; Tomography; Monitoring; Seasonal variations; Soil moisture; Temperature compensation; Embankment levee

Domaines: Géophysique [physics.geo-ph]; Construction hydraulique

Clara Jodry, Sergio Palma Lopes, Yannick Fargier, Martin Sanchez, Philippe Cote. 2D-ERT monitoring of soil moisture seasonal behaviour in a river levee: A case study. Journal of Applied Geophysics, 2019, 167, pp.140-151. ⟨10.1016/j.jappgeo.2019.05.008⟩. ⟨insu-02142990⟩