Key physical factors and processes affecting non-uniform and preferential flows in porous media
Convener: Laurent Lassabatere | Co-conveners: Majdi R. Abou Najm, Thomas Baumgartl, Jannes KordillaECSECS, Mandana ShayganECSECS

Preferential and non-uniform flows are induced by biotic (e.g. earthworms and roots) and abiotic factors and processes (e.g. wet-dry and freeze-thaw cycles, lithology and structure) as well as anthropogenic activities (e.g. tillage and cultivation methods in agricultural land, man-made landforms from waste rock dumping and disposal strategies in mining). The understanding of preferential flow is of premium importance in relation to soil hydrology, as it can move a considerable amount of water and solutes in porous media. Preferential flows can occur spatially from the pore scale, to entire catchments, across large regions. Temporally, the preferential processes can change during hydrological events, from within hours to seasonal events, and across inter-annual variations of years.
This session welcomes studies on experimental and theoretical challenges to identify, quantify, and model the key physical factors and processes that are responsible for preferential flows in porous media across scales (from pore scale to catchment scale). Contributions are welcome to reflect on experimental studies, novel approaches and advances in solutions to:
• Understand the geometry and connectivity, formation and dynamics of fissure, fractures and macropores and its effect on preferential flow;
• Understand the effect of physical processes and geochemical processes on the dynamics of macropores and fracture networks;
• Develop and refine models for quantifying preferential flow, from pore scale to pedon scale and entire catchments and landscapes;
• Unpacking the pore structure of soil using new methods and approaches, including the use of non-Newtonian fluids, for improved characterization of heterogeneous soils and the advancement of flow and transport modeling.