We have developed a powerful, and very general, new theory to explain "anomalous" (non-Fickian) chemical transport observed in fractured and heterogeneous porous formations. We are extending this theory, developing associated numerical models, and conducting laboratory experiments, for general applications to fractured and heterogeneous porous media.
Groundwater movement in naturally fractured and heterogeneous porous aquifers is highly complex, due to a strongly varying velocity field with multiscale correlation lengths. A key problem is how to describe tracer and contaminant movement in such systems. Realistic quantification of this movement is complicated by the uncertainty in characterization of aquifer properties. CTRW theory accounts for the often observed non-Fickian (or scale-dependent) dispersion behavior that cannot be properly quantified by using the advection-dispersion equation. The solutions provided here are valid for a wide range of transport regimes and dispersive behaviors.
We are studying the geometrical structure and hydraulic properties of fracture networks, and developing theories to explain (a) scaling behavior of network structure and hydraulic conductivity observed in naturally fractured geological formations, (b) measured variations in hydraulic behavior in deforming fractures, and (c) patterns of mineral precipitation and dissolution observed in natural fractures.
We are integrating theoretical, numerical and experimental studies to analyze reactive chemical and density-dependent transport phenomena in fractured and heterogeneous porous media.
We are developing theoretical, numerical and experimental studies to investigate flow and transport processes in soils and in the capillary fringe (water table region).
We are examining statistical growth models, and conducting laboratory experiments, to simulate and measure migration of multiphase (such as air-water) and immiscible fluids (such as dense non-aqueous phase liquids - DNAPLs - in groundwater) in heterogeneous porous media.
We are developing new catalytic methods and synthesizing new materials to transform persistent organic contaminants and heavy metals into less toxic compounds, involving both reduction and oxidation processes. We are also using laboratory experiments to investigate the feasibility and efficiency of emplacing various materials in permeable reactive barriers, and other configurations, for in situ remediation of contaminated groundwater.
