Infiltration models and soil characterisation for hemispherical and disc sources based on Green-Ampt assumptions

Abstract In the present paper a set of physically based expressions for estimating the infiltrated volume and the flow rate from hemispherical and disc sources are presented. The proposed formula depends on four parameters: the initial and the saturated soil water contents, the saturated hydraulic conductivity and the wetting front suction head. The developed models allow the accurate estimation of the infiltrated flow when compared with the same phenomena simulated with Richardś equation. Dimensionless expressions were also deduced which help draw general conclusions on the infiltration processes. Taking advantage of the small number of parameters included in the developed expressions, it was proposed a simple procedure for soils characterization. The method requires measuring both the initial and saturated soil water content and the infiltrated volume over time from a disc source and, aided with the developed expressions, allows deducing both the saturated hydraulic conductivity and the wetting front suction head.