Simple Laboratory Measurement of Unsaturated Hydraulic Conductivity

Abstract

A simple method called “upward infiltration method” is described for using common soil laboratory equipment to measure unsaturated hydraulic conductivity of soil samples in a short time. The method is based on measurement of water absorption rates under controlled tensions, which leads to an estimate of soil hydraulic conductivity during the wetting phase. The results are compared with those evaluated by the constant application rate method, the small increments of pressure change method, the one‐step method, and Jackson's theoretical model. The results of the upward infiltration method are in close agreement with the constant application rate method and are generally higher than the one‐step method and lower than Jackson's theoretical model. The measurement by this method is limited to about one meter of negative water pressure.