Estimation of the water content beneath the soil zone and above the zone of permanent saturation is notoriously difficult. The CWI team aims to overcome this difficulty by the use of electrical borehole tomography. Research associate and PhD student Anna Greve is working with Professor Ian Acworth and Assoc/Professor Bryce Kelly to develop new equipment.

Borehole tomography allows three dimensional monitoring of moisture changes in the soil profile. Borehole resistivity probes have been constructed and were tested in laboratory weighing lysimeters. Once tested in the laboratory the equipment has successfully been used in the field during the growing season 2007/08 (some results can be seen in the figure below). Field testing will be further extended during the upcoming season. Additional deep drainage measurements in field lysimeters and water level measurements in multilevel piezometers as well as data from the climate station at the field site will be used to develop a detailed relationship between electrical bulk conductivity and soil moisture content.