When can the local advection–dispersion equation simulate non-Fickian transport through rough fractures?

Non-Fickian solute transport is observed across many scales, which has motivated development of numerous non-Fickian-based models. Assuming that local fluid flow was estimable from the Modified Local Cubic Law, this study determined whether the local ADE better simulated non-Fickian transport through rough (3-D) fractures when local dispersion was described using either the Taylor dispersion coefficient ( D Taylor ) or the molecular diffusion coefficient ( D m ). The assessment was based on how well the local ADE compared to particle-tracking solutions for solute transport across a range of Péclét numbers ( Pe ) through two simulated fractures. Even though the local ADE is based on local Fickian transport processes, it was able to reproduce non-Fickian transport characteristics through these heterogeneous fractures. When supplying D Taylor to the local ADE, it extended the applicability of the local ADE to a threshold of Pe