Monitoring water flow in soils, using neutron and X-ray tomography

Abstract

Structures such as aggregates and fi ssures dominate the displacement of water, air, and solids in soil because they cause spatially non-uniform non-equilibrium fl ow. We can improve our understanding of these flow processes by making use of the recent advances in imaging techniques. Neutron radiography and tomography are efficient tools for real time monitoring of water distribution. X-ray tomography enables us to reconstruct the internal fabric of the soil at a resolution of a few microns. By combining the two methods, we discovered that micro-heterogeneities control the overall hydraulic behaviour of structured soils.