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A complete soil hydraulic model accounting for capillary and adsorptive water retention, capillary and film conductivity, and hysteresis
Author(s) -
Sakai Masaru,
van Genuchten Martinus Th.,
Alazba A. A.,
Setiawan Budi Indra,
Minasny Budiman
Publication year - 2015
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2015wr017703
Subject(s) - hydraulic conductivity , capillary action , hysteresis , conductivity , water retention , water content , materials science , saturation (graph theory) , soil science , soil water , water retention curve , porosity , geotechnical engineering , environmental science , composite material , chemistry , geology , mathematics , physics , condensed matter physics , combinatorics
A soil hydraulic model that considers capillary hysteretic and adsorptive water retention as well as capillary and film conductivity covering the complete soil moisture range is presented. The model was obtained by incorporating the capillary hysteresis model of Parker and Lenhard into the hydraulic model of Peters‐Durner‐Iden (PDI) as formulated for the van Genuchten (VG) retention equation. The formulation includes the following processes: capillary hysteresis accounting for air entrapment, closed scanning curves, nonhysteretic sorption of water retention onto mineral surfaces, a hysteretic function for the capillary conductivity, a nonhysteretic function for the film conductivity, and a nearly nonhysteretic function of the conductivity as a function of water content ( θ ) for the entire range of water contents. The proposed model only requires two additional parameters to describe hysteresis. The model was found to accurately describe observed hysteretic water retention and conductivity data for a dune sand. Using a range of published data sets, relationships could be established between the capillary water retention and film conductivity parameters. Including vapor conductivity improved conductivity descriptions in the very dry range. The resulting model allows predictions of the hydraulic conductivity from saturation until complete dryness using water retention parameters.