Non-Darcian flows in soil and geological porous media
Subsurface flows are part of the hydrologic cycle; they play important roles in rainfall partitioning and runoff generation, water quality and groundwater recharge. These flows often take place through small pores and cracks in soil and rocks and are represented by the well-known Darcy’s law for saturated flows and the analogous Buckingham-Darcy equation for unsaturated flows. The implicit assumptions in these constitutive equations may not hold in many geologic systems of interest ranging from soils with large biopores or shrinkage cracks, to rock formations with large fractures, to carbonate karst systems with large interconnected voids and channel networks. Differences in flow path can lead to large differences in geochemistry and light stable isotope ratios. Flow processes in such systems are notoriously difficult to represent, owing in part to the dominance of gravity and viscous interactions that differ from those postulated in the Darcy formulation, and to the lack of simple representative elementary volumes. For fractured aquifers, the REV may exceed 10,000 m3! This session invites contributions that address these challenges and provide the state-of-the-art description of modeling approaches and experimental methods for quantifying non-Darcian flow processes. We welcome contributions that address aspects of non-Darcian flows: such as process modeling with alternative equations of motion including inertial and fragmentation effects, use of geophysics for flow characterization and observation, and applications of geochemistry and tracers for flow path identification.
Fred Ogden, Dani Or, Mike Sukop, Nebo Jovanovic and Russell Harmon