A Generation of Research at the MADE Site and a View to the Future

Field studies at well-instrumented research sites have provided extensive data sets and important insights essential to develop and test transport theories and mathematical models. This presentation provides an overview of over 25 years of research and lessons learned at one of the classic field research sites, the Macrodispersion Experiment (MADE) site, on the Columbus Air Force Base in Mississippi. Since the mid-1980s, field data from the MADE site have been used extensively by researchers around the world to explore complex contaminant transport phenomena in highly heterogeneous porous media. Results from field investigations and modeling analyses suggested that connected networks of small-scale preferential flow paths and relative flow barriers exert dominant control on solute migration, spreading, and mixing processes. The classical advection-dispersion model was shown to inadequately represent plume-scale transport, while the dual-domain mass transfer model was found to reproduce the primary observed plume characteristics. The MADE site has served as a valuable natural observatory for contaminant transport studies, where new observations have led to better understanding and improved models have sprung out of analysis of new data. Continuing research at the MADE site is aiming to develop high-resolution characterization and parameterization approaches that will enable us to better predict contaminant transport in highly heterogeneous porous media.