Upward infiltration–evaporation method to estimate soil hydraulic properties

Peña-Sancho, C. and Ghezzehei, T.A. and Latorre, B. and González-Cebollada, C. and Moret-Fernández, D.

Hydrological Sciences Journal, vol. 62(10), pp. 1683–1693 , 2017.

Keywords

soil hydraulic properties, inverse methods, HYDRUS

Abstract

Determination of saturated hydraulic conductivity, Ks, and the van Genuchten water retention curve θ(h) parameters is crucial in evaluating unsaturated soil water flow. The aim of this work is to present a method to estimate Ks, α and n from numerical analysis of an upward infiltration process at saturation (Cap0), with (Cap0 + h) and without (Cap0) an overpressure step (h) at the end of the wetting phase, followed by an evaporation process (Evap). The HYDRUS model as well as a brute-force search method were used for theoretical loam soil parameter estimation. The uniqueness and the accuracy of solutions from the response surfaces, Ks–n, α–n and Ks–α, were evaluated for different scenarios. Numerical experiments showed that only the Cap0 + Evap and Cap0 + h + Evap scenarios were univocally able to estimate the hydraulic properties. The method gave reliable results in sand, loam and clay-loam soils.