Stochastic modeling of transient contaminant transport

A stochastic perturbation-based formulation for transient contaminant transport in the vadose zone was developed and implemented. The proposed methodology provides an efficient way to incorporate the small-scale variability of soil properties into large-scale models using effective parameters. A finite element solution of the stochastic differential equation for transient contaminant transport was formulated. The mean concentration value and its variance at each node were evaluated. The advantage of the proposed stochastic finite element approach is that only a few soil parameters are required to describe the variability of its stochastic properties. In addition, the proposed approach is neither site-specific nor contaminant-specific. A one-dimensional transient contaminant transport was simulated and the stochastic results were compared to deterministic and experimental results. The stochastic perturbation-based numerical formulation predicted the velocity of spreading of the contaminant much closer to the experimental measurements, as compared to the deterministic approach.