FACTORS INFLUENCING POINT MEASUREMENT OF NEAR-SURFACE SATURATED SOIL HYDRAULIC CONDUCTIVITY IN A SMALL SICILIAN BASIN

Hydraulic conductivity of saturated soil, K-s, controls many hydrological processes. Parameterization of basin hydrological models in terms of K-s is complicated and uncertain owing to the very high spatial variability of this soil property. A small Sicilian basin was intensively sampled by the simplified falling head technique to obtain spatially distributed K-s data, and an attempt to explain their spatial variability on the basis of soil physical characteristics, digital elevation model-derived topographic attributes and land cover was carried out. High K-s values were obtained when clay content was low and both elevation and mean slope were high. Moreover, differences in K-s among land cover classes were detected. However, soil texture was found to have a main role on K-s variability. This finding was supported by a subsequent intensive sampling of two areas differing by elevation and land cover. The conclusion was that, for the sampled basin, a good knowledge of the spatial distribution of the soil textural fractions is necessary to develop an appropriate sampling plan for K-s, regardless of both the position within the basin and land use. Copyright (C) 2016 John Wiley & Sons, Ltd.