Changes in the Electrical Conductivity of Infiltrating Rainwater

Wednesday, 17 December 2014
Adam Tew, Stanford University, Los Altos Hills, CA, United States
When water infiltrates into a soil, the electrical properties of that soil change in response to the presence of the fluid. The fluid’s electrical properties may also change due to dissolution and precipitation reactions with the soil minerals. The temporal and spatial changes of the fluid conductivity have the potential to change the interpretations of near-surface geophysical modeling.

Crunchflow was used to model the changes in fluid content which occur during infiltration into a simple soil system. A number of modifications were also tested to determine the behavior of more general systems and to determine the usefulness of this type of analysis for real-world locations.

The results showed that the reactivity of the local minerals was, not surprisingly, an important parameter in determining the soil fluid conductivity. When reactive minerals were present, equilibrium was quickly established throughout the profile at a higher conductivity than the infiltrating water. When reactive minerals were absent, there were significant spatial and temporal variations which extended over several days before a relatively steady soil fluid conductivity was achieved.