Jérôme Gaillardet
CRITEX coordinator Steering committee RBV scientific council WP 4.2 leader Professor Institut de Physique du Globe de Paris Visit Jérôme web page Visit Jérôme Workpackage page
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IAH congress 2016
The 43rd IAH congress (International Association of Hydrogeologists) will be held in Montpellier, France between 25 to 29th September 2016 www.60iah2016.org/en/programme/main-topics-and-provisional-sessions A “Hydrogeophysics” session (Topic 8, session 7) is included in the program (full session description below). This is an excellent opportunity to interact with a broad range of hydrogeologists and to highlight the value of geophysical methods to hydrogeology […]
Read moreThermal-plume fibre optic tracking (T-POT) test for flow velocity measurement in groundwater boreholes
We develop an approach for measuring in-well fluid velocities using point electrical heating combined with spatially and temporally continuous temperature monitoring using distributed temperature sensing (DTS). The method uses a point heater to warm a discrete volume of water. The rate of advection of this plume, once the heating is stopped, equates to the average flow velocity in the well. […]
Read moreInversion of generalized relaxation time distributions with optimized damping parameter
Retrieving the Relaxation Time Distribution (RDT), the Grains Size Distribution (GSD) or the Pore Size Distribution (PSD) from low-frequency impedance spectra is a major goal in geophysics. The “Generalized RTD” generalizes parametric models like Cole–Cole and many others, but remains tricky to invert since this inverse problem is ill-posed. We propose to use generalized relaxation basis function (for instance by […]
Read moreDetecting different water table levels in a shallow aquifer with combined P-, surface and SH-wave surveys: Insights from VP/VS or Poisson’s ratios
When applied to hydrogeology, seismicmethods are generally confined to the characterisation of aquifer geometry. The joint study of pressure- (P) and shear- (S) wave velocities (VP and VS) can provide supplementary information and improve the understanding of aquifer systems. This approach is proposed here with the estimation of VP/VS ratios in a stratified aquifer system characterised by tabular layers, well-delineated […]
Read moreActive-Distributed Temperature Sensing to continuously quantify vertical flow in boreholes
We show how a distributed borehole flowmeter can be created from armored Fiber Optic cables with the Active-Distributed Temperature Sensing (A-DTS) method. The principle is that in a flowing fluid, the difference in temperature between a heated and unheated cable is a function of the fluid velocity. We outline the physical basis of the methodology and report on the deployment […]
Read moreContribution of Magnetic Resonance Soundings for characterizing water storage in the unsaturated zone of karst aquifers
Understanding the role of the unsaturated zone in aquifer recharge and contaminant attenuation processes is a major challenge for the protection and management of karstic water resources. We present the potential of the MRS (Magnetic Resonance Soundings) geophysical method for characterizing the vadose zone of karst aquifers composed of epikarst and infiltration layers. To investigate the hydraulic functioning of the Durzon karst system located […]
Read moreInterpretation of magnetic resonance measurements in the varying earth’s magnetic field
At the scale of a magnetic resonance sounding (MRS) field setup, the earth’s magnetic field in the subsurface may vary laterally with depth and over time. These variations can be caused by different natural factors and generally cannot be compensated for by accurate tuning of the measuring device. The varying geomagnetic field (GMF) causes non resonance conditions of excitation that affect the amplitude and phase of […]
Read morePermanent electrical resistivity measurements for monitoring water circulation in clayey landslides
Landslides developed on clay-rich slopes are controlled by the soilwater regimeand the groundwater circulation. Spatially-distributed and high frequency observations of these hydrological processes are important for improving our understanding and prediction of landslide triggering. This work presents observed changes in electrical resistivity monitored at the Super-Sauze clayey landslide with the GEOMON 4D resistivity instrument installed permanently on-site for a period of one year. A […]
Read moreHydrogeophysical characterization of transport processes in fractured rock by combining push-pull and single-hole ground penetrating radar experiments
The in situ characterization of transport processes in fractured media is particularly challenging due to the considerable spatial uncertainty on tracer pathways and dominant controlling processes, such as dispersion, channeling, trapping, matrix diffusion, ambient and density driven flows. We attempted to reduce this uncertainty by coupling push-pull tracer experiments with single-hole ground penetrating radar (GPR) time-lapse imaging. The experiments involved different injection fractures, chaser […]
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