Comparison of Methods for the Interpretation of Modified Philip-Dunne Data

Estimation of field-saturated hydraulic conductivity (Kfs) is important for determining field infiltration capacity of soils. In this paper, different methods for interpreting Modified Philip-Dunne (MPD) data are evaluated to select the best-fit Kfs. The paper presents a data set other than the one used to develop the MPD to evaluate these methods. As part of the methods, the paper evaluates the current ASTM procedure and test method for the MPD infiltrometer test, which recommends minimizing error in the total head difference, ΔP, to estimate Kfs. Although each method uses a different approach to estimate Kfs, the direct-fit method proved to be the most appropriate based on the data used. The study highlights the effect of the method selected for MPD data interpretation on the estimated parameters.