Publication Date:
2015-10-24
Description:
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, non-hysteretic sorption of water retention onto mineral surfaces, a hysteretic function for the capillary conductivity, a non-hysteretic function for the film conductivity, and a nearly non-hysteretic 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 datasets, 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. This article is protected by copyright. All rights reserved.
Print ISSN:
0043-1397
Electronic ISSN:
1944-7973
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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