title: A proposed model to include a residual NAPL saturation in a hysteretic capillary pressure-saturation relationship.
abstract: A residual non-aqueous phase liquid (NAPL) present in the vadose zone can act as a contaminant source for many years as the compounds of concern partition to infiltrating groundwater and air contained in the soil voids. Current pressure-saturation-relative permeability relationships do not include a residual NAPL saturation term in their formulation. This paper presents the results of series of two- and three-phase pressure cell experiments conducted to evaluate the residual NAPL saturation and its impact on the pressure-saturation relationship. A model was proposed to incorporate a residual NAPL saturation term into an existing hysteretic three-phase parametric model developed by Parker and Lenhard [Water Resour. Res. 23(12) (1987) 2187], Lenhard and Parker [Water Resour. Res. 23(12) (1987) 2197] and Lenhard [J. Contam. Hydrol. 9 (1992) 243]. The experimental results indicated that the magnitude of the residual NAPL saturation was a function of the maximum total liquid saturation reached and the water saturation. The proposed model to incorporate a residual NAPL saturation term is similar in form to the entrapment model proposed by Parker and Lenhard, which was based on an expression presented by Land [Soc. Pet. Eng. J. (June 1968) 149].
authors.affiliation: Department of Civil and Environmental Engineering, Carleton University, Ottawa, Ontario, Canada. paul_van_geel@carleton.ca
authors.forename: P J
authors.initials: PJ
authors.lastname: Van Geel
authors.forename: S D
authors.initials: SD
authors.lastname: Roy
mesh_terms: D006536:Heptanes / Q000737:chemistry*; D006801:Humans; D008962:Models, Theoretical; D011312:Pressure; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D014872:Water Movements; D014874:Water Pollutants, Chemical
chemical_list: D006536:Heptanes; D012997:Solvents; D014874:Water Pollutants, Chemical