Model estimates soil permeability using induced polarization


  • Colin Schultz


The speed at which water flows through the ground depends on a number of physical parameters, including the density of the soil and the number and sizes of open pores, with the cumulative effect of these parameters dictating the soil's permeability. When exposed to an electric field, sediment grains within the soil get polarized because of an extremely thin structure that surrounds each grain known as the electrical double layer. The electrical double layer consists of a thin layer of adsorbed ions and a diffuse layer of ions that encircle each soil particle. Researchers are able to measure the polarization of the soil to nonintrusively estimate the soil's textural properties, and hence its permeability, with the polarization of the soil being controlled by the polarization of the electrical double layer.