Image Analysis for Determination of Dye Tracer Concentrations in Sand Columns

Abstract

Abstract Dye tracers can be used to visualize flow paths in soils. We used digital image analysis to determine the spatial distribution of dye concentrations in a quartz sand column. Color slides and near‐infrared black‐and‐white photographs were taken from a sand column that was cut in halves longitudinally after a point‐source dye infiltration experiment. In a separate calibration experiment, sand samples were prepared with known water content and dye concentration. Photographs of such sample arrays were used as training areas for image analysis. Image analysis is a viable way for obtaining a high spatial resolution of tracer concentrations and provides a quantitative basis for describing different solute mixing regimes.