A high-resolution system for the quantification of preferential flow in undisturbed soil using observations of tracers

Solute transport studies are increasingly being used to characterise flow mechanisms in both the field and laboratory. Realisation that solutes move preferentially through soil into groundwaters has meant that research in this area has increased in importance. The objectives of this study were to develop a method for the high-resolution examination of transport mechanisms in the laboratory, using techniques which overcame previous limitations associated with extrapolating data from soils stained with dye tracers. This paper describes a method for the collection of a large undisturbed soil column subjected to a rainfall simulation and with time domain reflectometery probes (TDR) inserted as part of a dye tracer study to examine the physical and morphological properties associated with preferential flow. A method for the acquisition of serial images to enable a high-resolution quantification of dye-stained pathways is proposed. Initial results indicated that the system provides an opportunity for detailed examination of preferential flow in two dimensions and in three dimensions through inference.