title: Influence of small-scale heterogeneities on contaminant transport in fractured crystalline rock.
abstract: We present a sequence of purely advective transport models that demonstrate the influence of small-scale geometric inhomogeneities on contaminant transport in fractured crystalline rock. Special weight is placed on the role of statistically generated variable fracture apertures. The fracture network geometry and the aperture distribution are based on information from an in situ radionuclide retardation experiment performed at Grimsel test site (Swiss Alps). The obtained breakthrough curves are fitted with the advection dispersion equation and continuous-time random walks (CTRW). CTRW is found to provide superior fits to the late-arrival tailing and is also found to show a good correlation with the velocity distributions obtained from the hydraulic models. The impact of small-scale heterogeneities, both in fracture geometry and aperture, on transport is shown to be considerable.
authors.affiliation: Laboratory for Waste Management, Paul Scherrer Institute, Villigen, Switzerland. ralph.mettier@psi.ch
authors.forename: Ralph
authors.initials: R
authors.lastname: Mettier
authors.forename: Georg
authors.initials: G
authors.lastname: Kosakowski
authors.forename: Olaf
authors.initials: O
authors.lastname: Kolditz
mesh_terms: D003198:Computer Simulation; D005618:Fresh Water / Q000737:chemistry*; D008903:Minerals / Q000032:analysis*; D008962:Models, Theoretical; D013557:Switzerland; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply
chemical_list: D008903:Minerals; D014874:Water Pollutants, Chemical