IN SITU MEASUREMENTS OF SOIL HYDRAULIC CONDUCTIVITY USING POINT APPLICATION OF WATER

Abstract

A method for estimating hydraulic conductivity from in-situ measurements of soils hydraulic parameters froma point application of water was tested for three soil types. The method is based on Woodings (1968) and Warricks(1985) solutions of water flow from a shallow circular pond and point source, respectively. Measurements of the saturatedradii and the associated flow rates are used to determine the saturated hydraulic conductivity and for the assumedGardners (1958) exponential relationship between hydraulic conductivity and soil matric head. Effects of flow rate onsaturated and unsaturated surface wetted regimes were also observed. The surface wetted areas were found to besignificantly affected by flow rate in all three soils. The results from the point application method were compared to thosefrom ring infiltrometer measurements and gave consistent values for saturated hydraulic conductivity. The methodssimplicity, repeatability and the ability to make rapid in-situ measurement makes it practical and applicable to use undervarying conditions.