A Coupled Electrical Resisü vity-Infi ltraü on Model for We´ ng Front Evaluaü on

A coupled resisƟ vity–infi ltraƟ on model was developed. The infi ltraƟ on model relies on the analyƟ cal soluƟ on of a fully developed and sharp weƫ ng front using the Green–Ampt approximaƟ on, thereby reducing the resisƟ vity model to the simple two-layer case. The Green–Ampt approximaƟ on is a highly simplisƟ c soil model that has limited applicability to real soils. The forward model demonstrates the eff ects of a voltage drop with Ɵ me for a pole–pole, Wenner, and dipole–dipole electrode arrangement for a moving weƫ ng front. The velocity of the weƫ ng front can be obtained directly from the Ɵ me series curve by normalizing the measured apparent resisƟ vity to the resisƟ vity of the wet layer (esƟ mated from the voltage at Ɵ me t = ∞) and ploƫ ng against the reciprocal of Ɵ me mulƟ plied by the electrode separaƟ on. Furthermore, if the cumulaƟ ve infi ltraƟ on or other parameters are known, then the hydraulic conducƟ vity can be calculated.