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Simple Method for Predicting Drainage from Field Plots
Author(s) -
Sisson J. B.,
Ferguson A. H.,
Genuchten M. Th.
Publication year - 1980
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1980.03615995004400060004x
Subject(s) - partial differential equation , simple (philosophy) , drainage , differential equation , mathematics , infiltration (hvac) , hyperbolic partial differential equation , mathematical analysis , hydrology (agriculture) , geology , geotechnical engineering , physics , meteorology , ecology , philosophy , epistemology , biology
When the one‐dimensional moisture flow equation is simplified by applying the unit gradient approximation, a first‐order partial differential equation results. The first‐order equation is hyperbolic and easily solved by the method of P. D. Lax. Three published K (θ) relationships were used to generate three analytical solutions for the drainage phase following infiltration. All three solutions produced straight lines or nearly straight lines when log of total water above a depth was plotted versus log of time. Several suggestions for obtaining the required parameters are presented and two example problems are included to demonstrate the accuracy and applicability of the method.