Application of geophysical methods in describing spatial variability of saturated hydraulic conductivity in the zone of aeration

Abstract

An attempt is made to apply surface geophysical methods for the determination of spatial variability of saturated hydraulic conductivities. Methods of vertical electrical sounding and dipole electromagnetic profiling were tested in an area of 100 × 100 m. Measurements were taken on a square grid 20 by 20 m. The soil profile, formed by coarse acid brown soil of relatively high permeability underlain by a weathered gneiss substratum, is represented by four geoelectrical layers. The saturated hydraulic conductivities of both individual soil layers and the integral soil medium were compared with the geophysical parameters. They were estimated by a laboratory constant head permeameter and in the field by ponding infiltration measurements. The hydraulic conductivities of the individual soil layers were statistically derived from the resistivities of the layers, while the estimation of the conductivities of the integral soil medium generally needed some multivariate treatment of the geoelectrical data. It was concluded that the geoelectrical methods may be effectively applied to determine the spatial variation pattern of both individual and integral saturated hydraulic conductivities in the field, to estimate their relations to the deeper structural and tectonic phenomena and to differentiate soil layers according to their properties.