High-characterization of Vadose Zone Dynamics in Limestone Underground Quarries by Time Domain Reflectometry

The aim of this paper is to study the vadose zone dynamics during a hydrological cycle. The application of the Time Domain Reflectometry (TDR) method to determine the water content of porous rock has been widely investigated. More than 657 point measurements of rock water content observed during a hydrological cycle and distributed among three abandoned underground quarries in Gironde, France show a permanently undersaturated limestone. Two periods of maximum water content correspond to two occurring effective precipitations. The dephasing and amplitude attenuation of the hydraulic wave with the depth can be modelled and explained by the physical properties of the porous medium. Maps of the spatial distribution of water content show the heterogeneity of water flow in a vadose zone.