A methodology to map the surface soil hydraulic conductivity at saturation in mesoscale Alpine basins

An experimental field- and laboratory-based methodology is presented to get quantitative maps of the upper soil vertical hydraulic conductivity at saturation. The hypothesis that the soil response to a rainfall event is largely influenced by its lithology, and land cover is introduced, obtaining a preliminary qualitative infiltration map. A protocol of soil investigation, based on the use of the single-ring infiltrometer and of the laboratory falling-head permeameter, is then defined. In situ and laboratory measurements of the upper soil conductivity are performed for each infiltration class and a mean value is derived. Two different methods to treat the field data are recalled, and their reliability is discussed after the analysis of the data collected in our campaigns. As an application of the methodology, the conductivity maps of three mesoscale Alpine basins were drawn. The use of field infiltration tests interpreted within a 2-D theoretical framework was addressed as a reference standard procedure.