Estimating contaminant migration in the context of waste disposal and/or environmental remediation of polluted soils
requires a complete understanding of the underlying transport processes. In unsaturated porous media, water content
impacts directly on porous solute transfer. Depending on the spatial distribution of water content, the flow pathway is
more complex than in water saturated media. Dispersivity is consequently dependent on water content. Non-reactive
tracer experiments performed using unsaturated sand columns confirm the dependence of dispersivity with pore
velocity; moreover, a power law relationship between dispersivity and water content is evidenced.