Project Start Date October 1997
This research addresses the behavior of multiphase flow in natural heterogeneous, porous media. Its objectives are to quantify the role of aquifer heterogeneity in the field-scale flow immiscible liquids, the distribution of residual nonwetting liquids, and the rate of dissolution from the residual phase, and to develop strategies for data collection and analysis. One of the expected outcomes of this effort will be to derive the functional dependence of immiscible flow on the moments of the spatially varying hydraulic properties. The goal will be to derive a means of estimating field-scale, effective parameters which incorporate the effect of the imperfectly characterized heterogeneity. In addition to its practical applications, this research contributes to a general understanding of the behavior of heterogeneous natural systems. The graphic illustrates the results of a computer simulation of the distribution (in a vertical section about 6 feet deep and 70 feet long) of the saturation of a DNAPL (dense non-aqueous phase liquid) contaminant (tetracholoroethane) in a mildly het-erogeneous sandy aquifer (Borden Site) resulting from the infiltration of DNAPL at a rate of 10 gallons/square foot/day into the initially water-saturated aquifer. As a result of the natural heterogeneity of the flow properties, the distribution of DNAIPL saturation is highly irregular, with saturation ranging from over 0.8 to less than 0.2. The project is developing probabilistic methods of predicting the variability of the distribution of DNAPL in aquifers, as this information is needed to develop effective methods of cleaning up such contamination.