USE OF SOIL TEXTURE, BULK DENSITY, AND SLOPE OF THE WATER RETENTION CURVE TO PREDICT SATURATED HYDRAULIC CONDUCTIVITY

Abstract

With advances in computer software and hardware, mathematical subsurface flow models are routinely beingused for many field applications. The application of the subsurface models depends on the availability of accurate inputparameters describing the hydraulic properties of the soil, especially the soil matrix saturated hydraulic conductivity.Saturated hydraulic conductivity can be measured directly which is very costly and time consuming, or estimatedindirectly from more easily measured data such as soil texture, the most readily available soil property in the UnitedStates. This study grouped more than 900 saturated hydraulic conductivities for the soil matrix according to the USDAsoil texture classes and two porosity classes. The geometric mean and a variability measure are reported. Comparingthese values with previously published values indicates that the new data yield higher values for the heavy textured (clay)soils. Also, values for the fine sand classes which were not previously available are reported. A redefined version of theKozeny-Carman saturated hydraulic conductivity equation based on effective porosity and the slope of the water retentioncurve is presented for estimating the saturated hydraulic conductivity for the soil matrix.