Estimation of Transport Parameters Using Forced Gradient Tracer Tests in Heterogeneous Aquifers

摘要

The evaluation of risk to the environment by subsurface contamination remains one of the major challenges to the Army. Numerical models such as the U.S. Army's Groundwater Modeling System that simulate water flow and chemical transport are increasingly used in remediation design and analysis. This research contributes toward a better understanding of field- testing methods to obtain model parameters. The focus was on both reactive and sorptive parameters. The experimental component of the study was conducted in a three-dimensional, intermediate-scale test tank to obtain accurate data on the behavior of nonreactive and sorptive tracers. This database was used to validate a numerical model, which was then used to analyze behavior over a wider range of scales. A large number of hydraulic and tracer tests were performed in the test aquifer, in three different mean flow configurations: uniform flow, radially divergent flow, and convergent flow. This is a very unique data set that will be available to other researchers. It will help to evaluate models and stochastic theories of up scaled flow and transport. In a related study, a fundamental theoretical analysis of the relationship between surface properties of rock fractures and effective behavior of transport was carried out. The results of both studies are of theoretical and practical significance. This report summarizes the most important results of research in the two areas: intermediate-scale experiments on non-reactive and reactive transport in heterogeneous porous media, and transport with wall reactions in fractures. A list of 18 published papers, conference papers, and papers about to be published is included. (2 refs.).