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Title: MULTICOMPONENT GEOCHEMICAL TRANSPORT MODELING USING THE HYDRUS COMPUTER SOFTWARE PACKAGES

Author
item SIMUNEK, JIRKA - UC RIVERSIDE, CA
item JACQUES, D - SCK-CEN,BOERETANG,BELGIUM
item Van Genuchten, Martinus
item MALLANTS, D - SCK-CEN,BOERETANG,BELGIUM

Submitted to: Proceedings of the International Salinity Forum
Publication Type: Proceedings
Publication Acceptance Date: 4/11/2005
Publication Date: 4/25/2005
Citation: Simunek, J., Jacques, D., Van Genuchten, M.T., Mallants, D. 2005. Multicomponent geochemical transport modeling using the HYDRUS computer software packages. In: Proceedings of the International Salinity Forum, Managing Saline Soils and Water: Science, Technology, and Soil Issues. April 25-27, 2005. Riverside, CA pp:183-186.

Interpretive Summary: The fate and transport of agricultural and industrial contaminants in the subsurface is affected by a multitude of physical, chemical and biological processes. Physical processes including water flow, solute transport by flowing water and diffusion, and heat movement. Chemical processes include precipitation-dissolution, adsorption and volatilization. The transport and transformation of many contaminants is further mediated by bacteria in the subsurface. Simulating these and related processes requires a coupled reactive transport code that integrates the physical processes of water flow and solute transport with a range of biogeochemical processes. In this paper we summarize two recently developed coupled geochemical models that are both based on the widely used HYDRUS-1D software package. One of these is restricted to the fate and transport of major ions, while the other model accounts for a wide range of chemical and biological reactions. Results are important for scientists and engineers trying to assess the field-scale transport of salts, toxic trace elements, and many other contaminants.

Technical Abstract: The subsurface fate and transport of agricultural and industrial contaminants, as well as many naturally occurring elements, is affected by a multitude of complex, interactive physical, chemical and biological processes. Physical processes including water flow by capillary and gravitational forces, solute transport due to advection, dispersion and diffusion in the liquid and gaseous phases, as well as heat transport due to convection and conduction. Chemical processes include complexation reactions, cation exchange, precipitation-dissolution, sorption-desorption and volatilization, among other reactions. The transport and transformation of many contaminants is further mediated by subsurface aerobic or anaerobic bacteria. Simulating these and related processes requires a coupled reactive transport code that integrates the physical processes of water flow and advective-dispersive solute transport with a range of biogeochemical processes. In this paper we summarize two recently developed coupled geochemical models that are both based on the widely used HYDRUS-1D software package. One of these is restricted to the fate and transport of major ions, while the other model accounts for an unprecedented range of instantaneous and kinetic chemical and biological reactions.