Use of soil texture, bulk density, and slope of the water retention curve to predict saturated hydraulic conductivity

With advances in computer software and hardware, mathematical subsurface flow models are routinely being used for many field applications. The application of the subsurface models depends on the availability of accurate input parameters 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 estimated indirectly from more easily measured data such as soil texture, the most readily available soil property in the United States. This study grouped more than 900 saturated hydraulic conductivities far the soil matrix according to the USDA soil texture classes and two porosity classes. The geometric mean and a variability measure are reported. Comparing these 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 the Kozeny-Carman saturated hydraulic conductivity equation based on effective porosity and the slope of the water retention curve is presented for estimating the saturated hydraulic conductivity for the soil matrix.