Comparison of Field and Laboratory Determined Hydraulic Conductivity Values

Abstract Several new methods of determining hydraulic conductivity ( K )‐volumetric water content (θ) relations have been developed recently. Emphasis is on simplification of procedures that determine K (θ) relations in the field. This paper compares four different procedures by which K (θ) relations were determined for several horizons of a Troup loamy sand (Grossarenic Paleudults). The first procedure consisted of in situ measurements of water content and pressure head profiles following irrigation. All measurements were obtained with the soil surface covered to prevent evaporation. The data were used to calculate K (θ) values. The second procedure consisted of a model that used water retention curves and saturated K values determined on undisturbed core samples. The third method was a variation of the second in that water retention data were used as measured in situ. The fourth method used in situ measured water content data only. For the coarse textured soil used in this investigation the latter method was modified in that two empirical equations were needed instead of one to represent one K (θ) relation. All four methods resulted in K (θ) relations that were in fairly good agreement.