The occurrence and transport of contaminants in the subsurface is a widespread problem. Because our groundwater resources are both limited and valuable, it is important that we develop methods to both protect and remediate these resources. The development of appropriate mathematical models for contaminant movement in geologic materials allows practitioners and researchers to predict contaminant behavior, which is critical for groundwater protection.
In this project, the investators are studying the movement of contaminants in highly heterogeneous media. In geological materials heterogeneity- basically the spatial variability of the material- can be enormous, and subsurface contaminants are often chemically reactive. Most existing mathematical models do not well represent transport and reaction in such highly heterogeneous materials. One mathematical approach that has been used extensively in groundwater prediction is to treat dissolved chemical species as if they were a cloud of discrete particles moving with the groundwater. The goal of this project is to develop new representations of such particle models to include mathematical representations of particle motion when highly heterogeneous media are encountered, and to add rules that allow one to represent reactions. The investigators have formed a unique collaboration between geoscientists, engineers, and mathematicians to develop this research. The work will focus on (1) the fundamental mathematical methods necessary to represent reactive contaminant transport by particle models, and (2) validation of these mathematical models by direct, large-scale (meters or more) controlled laboratory experiments in highly heterogeneous materials. The practical results of this effort will be (1) new results in the mathematical sciences that further our understanding of particle-based models, and (2) new models that can be used by hydrologists and engineers to more accurately predict contaminant transport and reaction in groundwater systems.
