Modelling of contaminant transport in unsaturated soils is necessary to achieve an improved understanding of pollutant migration
in the vadose zone, which differs significantly from that of fully saturated porous media. This paper deals with the application
of a meshless method called Element Free Galerkin Method for modelling the contaminant transport through the unsaturated porous
media with transient flow condition. A one dimensional advection-dispersion equation with linear retardation is considered.
The unknown concentration values are approximated by using moving least square approximants, which are constructed by using
a weight function, a linear basis function and a set of non-constant coefficients. The weak form of the governing equation
is formulated and Lagrange multiplier method is used for enforcing the essential boundary condition. The van Genuchten model
is used for describing the hydraulic properties of the soil. A numerical example is presented to illustrate the applicability
of the proposed method and the results are compared with those obtained from the finite element method.
Key words contaminant transport - element free Galerkin method - continuous source - partially saturated soil - van Genuchten model