The objective of this project is to devise and validate a transport model that can be used to estimate the spatial variation of solute concentration and the retardation of solute migrating through channels in a fractured porous medium. Laboratory experiments will be conducted to determine the effects of both small and large scale fracture aperture variations on the dispersion and retardation of solute migrating through a channelized, fractured porous medium. Experiments investigating small scale aperture variations will be analyzed to determine the fluid flow and solute dispersion which arises from fluid migration through regions of the fracture that subjected to a considerable degree of rock-to-rock contact. Experiments assessing the effects of large scale aperture variations will investigate the highly mobile flow channels which develop in a fractured porous medium and provide a basis for estimating the mass transfer of solute between highly mobile fracture channels and the less mobile areas within the fractures. The results of these experiments will be combined with a theoretical analysis of transport processes to estimate the dispersion and retardation of solute migrating through channels in fractured rocks due to interactions with low mobility fluids in the fracture and diffusion and adsorption of solute in the rock matrix. The resulting solute transport model can then be used to simulate contaminant migration in channelized, fractured media. This research is likely to improve current models used in describing the process by which fluids and solutes move through fractured porous media. This is of importance in predicting the impact of pollutants from storage sites on groundwater quality.
