title: Highly parameterized inversion of groundwater reactive transport for a complex field site.
abstract: In this study a numerical groundwater reactive transport model of a shallow groundwater aquifer contaminated with volatile organic compounds is developed. In addition to advective-dispersive transport, the model includes contaminant release from source areas, natural attenuation, abiotic degradation by a permeable reactive barrier at the site, and dilution by infiltrating rain. Aquifer heterogeneity is parameterized using pilot points for hydraulic conductivity, specific yield and groundwater recharge. A methodology is developed and applied to estimate the large number of parameters from the limited data at the field site (groundwater levels, groundwater concentrations of multiple chemical species, point-scale measurements of soil hydraulic conductivity, and lab-scale derived information on chemical and biochemical reactions). The proposed methodology relies on pilot point parameterization of hydraulic parameters and groundwater recharge, a regularization procedure to reconcile the large number of spatially distributed model parameters with the limited field data, a step-wise approach for integrating the different data sets into the model, and high performance computing. The methodology was proven to be effective in reproducing multiple contaminant plumes and in reducing the prior parameter uncertainty of hydraulic conductivity and groundwater recharge. Our results further indicate that contaminant transport predictions are strongly affected by the choice of the groundwater recharge model and flow parameters should be identified using both head and concentration measurements.
authors.affiliation: Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, Netherlands. Electronic address: carniato.luca@gmail.com.
authors.forename: Luca
authors.initials: L
authors.lastname: Carniato
authors.affiliation: Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, Netherlands.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Schoups
authors.affiliation: Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, Netherlands.
authors.forename: Nick
authors.initials: N
authors.lastname: van de Giesen
authors.affiliation: Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium; University of Ghent, Coupure Links 653, B-9000 Ghent, Belgium; University of Antwerp, Groenenborgerlaan, 2000 Antwerp, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Seuntjens
authors.affiliation: Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium.
authors.forename: Leen
authors.initials: L
authors.lastname: Bastiaens
authors.affiliation: SAPION, Oude Bevelsesteenweg 51, 2560 Nijlen, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Sapion
mesh_terms: D001530:Belgium; D060587:Groundwater / Q000737:chemistry*; D062070:Hydrology; D008962:Models, Theoretical; D011891:Rain; D012987:Soil / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000737:chemistry*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D012987:Soil; D055549:Volatile Organic Compounds; D014874:Water Pollutants, Chemical
keywords: Groundwater recharge; Heterogeneity; Inverse modeling; Pilot points; Reactive transport