Abstract
Highly-resolved simulations and flow and transport in an alluvial system at the Lawrence Livermore National Laboratory (LLNL) site explore the role of diffusion in the migration and recovery of a conservative solute. Heterogeneity is resolved to the hydrofacies scale with a discretization of 10.0, 5.0 and 0.5m in the strike, dip and vertical directions of the alluvial-fan system. Transport simulations rely on recently developed random-walk techniques that accurately account for local dispersion processes at interfaces between materials with contrasting hydraulic and transport properties. Solute migration and recovery by pump and treat are shown to be highly sensitive to magnitude of effective diffusion coefficient. Further, transport appears significantly more sensitive to the diffusion coefficient than to local-scale dispersion processes represented by a dispersivity coefficient. Predicted hold back of solute mass near source locations during ambient migration and pump-and-treat remediation is consistent with observations at LLNL, and reminiscent of observations at the MADE site of Columbus Air Force Base, Mississippi. Results confirm the important role of diffusion in low-conductivity materials and, consequently, its impact on efficacy of pump-and-treat and other remedial technologies. In a typical alluvial system on a decadal time scale this process is, in part, fundamentally nonreversible because the average thickness of low-K hydrofacies is considerably greater than the mean-square length of penetration of the solute plume.
Similar content being viewed by others
References
Adams, E. E. and Gelhar, L. W.: 1992, Field study of dispersion in a heterogeneous aquifer. 2. Spatial moments analysis, Water Resour. Res. 28(12), 3293-3307.
Anderson, M. P. and Woessner, W. W.: 1992, Applied Groundwater Modeling, Simulation of Flow and Advective Transport, Academic Press.
Archie, G. E.: 1942, The electrical resistivity log as an aid in determining some reservoir characteristics, Trans. Am. Inst. Min. Metall. Pct. Eng. 146, 54-62.
Boggs, J. M., Young, S. C., Beard, L. M., Gelhar, L. W., Rehfeldt, K. R. and Adams, E. E.: 1992, Field study of dispersion in a heterogeneous aquifer. 1. Overview and site description, Water Resour. Res. 28(12), 3281-3291.
Carle, S. F.: 1996, A transition probability-based approach to geostatistical characterization of hydrostratigraphic architecture, PhD Dissertation, University of California, Davis.
Carle, S. F. and Fogg, G. E.: 1997, Modeling spatial variability with one-and multidimensional Markov chains, Math. Geol. 28, 453-476.
Carle, S. F., LaBolle, E. M., Weissmann, G. S., VanBrocklin, D. and Fogg, G. E.: 1998, Geostatistical simulation of hydrofacies architecture: A transition probability/Markov approach, In: G. S. Fraser and J. M. Davis (eds), SEPM Concepts in Hydrogeology and Environmental Geology No. 1, Hydrogeologic Models of Sedimentary Aquifers, SEPM (Society for Sedimentary Geology), Tulsa, Oklahoma.
Cvetkovic, V. D., Dagan, G. and Shapiro, A. M.: 1991, An exact solution of solute transport by one-dimensional random velocity fields, Stoch. Hydrol. Hydraulics 5, 45-54.
Dagan, G.: 1989, Flow and Transport in Porous Formations, Springer-Verlag, Berlin, Heidelberg, 465 pp.
Feenstra, S., Cherry, J. A., Sudicky, E. A. and Haq, Z.: 1984, Matrix diffusion effects on contaminant migration from an injection well in fractured sandstone, Ground Water 22(3), 307-316.
Fogg, G. E., Noyes, C. D. and Carle, S. F.: 1998, Geologically-based model of heterogeneous hydraulic conductivity in an alluvial setting, Hydrologeol. J. 6, 131-143.
Fogg, G. E., Carle, S. F. and Green, C.: A connected-network paradigm for the alluvial aquifer system, In: D. Zhang (ed.), Theory, Modeling and Field Investigation in Hydrogeology: A Special Volume in Honor of Shlomo P. Neuman's 60th Birthday, Geological Society of America Special Publication, in press.
Galloway, W. E. and Hobday, D. K.: 1996, Terrigenous Clastic Depositional Systems: Applications to Fossil Fuel and Groundwater Resources, 2nd edn, Springer-Verlag, 491 pp.
Gelhar, L. W. and Axness, C. L.: 1983, Theree-dimensional stochastic analysis of macrodispersion in aquifers, Water Resour. Res. 19(1), 161-180.
Gelhar, L.W.: 1986, Stochastic subsurface hydrology from theory to applications, Water Resour. Res. 22(9), 135S-145S.
Gelhar, L.W.: 1993, Stochastic Subsurface Hydrology, Prentice Hall, New Jersey.
Gillham, R. W., Sudicky, E. A., Cherry, J. A. and Frind, E. O.: 1984, An advection diffusion concept for solute transport in heterogeneous unconsolidated geologic deposits, Water Resour. Res. 20(3), 369-378.
Grathwohl, P.: 1998, Diffusion in Natural Porous Media: Contaminant Transport, Sorption/Desorption and Dissolution Kinetics, Kluwer Academic Publishers, Norwell, Massachusetts.
Haggerty R. and Gorelick, S. M.: 1995, Multiple-rate mass transfer for modeling diffusion and surface reactions in media with pore-scale heterogeneity, Water Resour. Res. 31(10), 2383-2400.
Hoffman, F., Blake, R. G., Demir, Z., Gelinas, R. J., McKereghan, P. F. and Noyas, C. D.: 1997, A conceptual model and remediation strategy for VOCs in Low Organic Carbon Unconsolidated Sediments, Lawrence Livermore National Laboratory, UCRL-JC-125199 Rev. 1.
Kapoor, V. and Gelhar, L. W.: 1994, Transport in three-dimensionally heterogeneous aquifers, 1, Dynamics of concentration fluctuations, Water Resour. Res. 30(6), 1775-1788.
LaBolle, E. M., Fogg, G. E. and Tompson, A. F. B.: 1996, Random-walk simulation of transport in heterogeneous porous media: local mass-conservation problem and implementation methods, Water Resour. Res. 32(3), 583-593.
LaBolle, E. M., Quastel, J. and Fogg, G. E.: 1998, Diffusion theory for transport in porous media: Transition-probability densities of diffusion processes corresponding to advection-dispersion equations, Water Resour. Res. 34(7), 1685-1693.
LaBolle, E. M., Quastel, J., Fogg, G. E. and Gravner, J.: 1999, Diffusion processes in composite porous media: Generalized stochastic differential equations and their numerical integration by random walks, Water Resour. Res. in press.
LaBolle: 1999, Simulation of diffusion processes in porous media, PhD Dissertation, U.C. Davis.
Mackay, D. M. and Cherry, J. A.: 1989, Groundwater contaminantion: Pump-and-treat remediation, Environ. Sci. Technol. 23, 630-636.
Matheron, G. and de Marsily G.: 1980, Is transport in porous media always diffusive? A counterexample, Water Resour. Res. 16, 901-917.
McDonald, M. G. and Harbaugh, A.W: 1988, A modular three-dimensional finite-difference groundwater flow model. US Geological Survey Techniques of Water-Resources Investigations Book 6, Chapter A1, p. 586.
Mercer, J. W., Skipp, D. C. and Giffin, D.: 1990, Basics of Pump-and-Treat Ground-Water Remediation Technology, EPA/600/8-90/003, Ada, Okla., EPA, R.S. Kerr Environmental Research Laboratory, p. 31.
National Research Council (NRC): 1994, Alternative for Ground Water Cleanup, National Academy Press, Washington, D.C.
Noyes, C. N.: 1990, Hydrostratigraphic analysis of the Pilot Remediation Test Area, LLNL, Livermore, California, MS Thesis, University of California, Davis, 165 pp.
Nyer, E. K.: 1993, Aquifer restoration: pump and treat and the alternatives, Groundwater Monitor. Rev. Winter, pp. 89-92.
OSWER: 1997, Directive 9200.4-17, use of monitored natural attenuation at superfund, RCRA corrective action, and underground storage tank sites, U.S. EPA office of SolidWaste and Emergency Response Directive 9200.4-17, 29 pp.
Pollock, D. W.: 1988, Semianalytical computation of path lines for finite-difference models, Ground Water 26(6), 743-760.
Rügner, J., Kleineidam, S. and Grathwohl, P.: 1998, Long-term sorption kinetics of phananthrene in aquifer materials, Environ. Sci. Technol. 33(10), 1645-1651.
Tompson, A. F. B. and Gelhar, L. W.: 1990, Numerical simulation of solute transport in threedimensional, randomly heterogeneous porous media, Water Resour. Res. 26(10), 2541-2562.
Tompson, A. F. B., Falgout, R. D., Smith, S. G., Bosl, W. J. and Ashby, S. F.: 1998, Analysis of subsurface contaminant migration and remediation using high performance computing, Adv. Water Resour. 22(3), 203-221.
Tompson A. F. B., Carle, S. F., Rosenberg, N. D. and Maxwell, R. M.: 1999, Analysis of groundwater migration from artificial recharge in a large urban aquifer: a simulation perspective, Water Resour. Res. 35(10), p. 2981.
Werth, C. J. and Reinhard, M.: 1999, Counter-diffusion of isotopically labeled trichloroethylene in silica gel and geosorbent micropores: column results, Eniron. Sci. Technol. 33, 730-736.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
LaBolle, E.M., Fogg, G.E. Role of Molecular Diffusion in Contaminant Migration and Recovery in an Alluvial Aquifer System. Transport in Porous Media 42, 155–179 (2001). https://doi.org/10.1023/A:1006772716244
Issue Date:
DOI: https://doi.org/10.1023/A:1006772716244