The solute dispersivity is one of the most important factors to evaluate solute transport in groundwater environment. In this study, the non-destructive method to evaluate solute dispersivity by the thermal image of the thermal tracer test was proposed. Heated sodium chloride was used as tracer injected into the flow tank packed glass beads. Electrical conductivity and temperature change were observed at the 5 points of the downstream. According to the results of this experiment, thermal diffusivity of this system was evaluated. The thermal images were photographed at the tracer experiment under the same conditions. The method to evaluate solute dispersivity from this thermal image was examined. As a result of this study, it is possible to investigate solute dispersivity from the thermal image, if the thermal diffusivity of the medium is evaluated accurately.
