ARS | Publication request: THE IDSFIT CODE FOR INVERSE ESTIMATION OF FIELD HYDRAULIC PROPERTIES USING A DISC INFILTROMETER

Submitted to: Electronic Publication
Publication Type: Other
Publication Acceptance Date: July 31, 2002
Publication Date: July 31, 2002

Technical Abstract: The tension disc infiltrometer has become a valuable tool to investigate the hydraulic properties of soils at or near the surface. Inverse optimization of parameters offers an economical means to infer soil hydraulic properties from tension disc infiltrometer data. Inverse procedures tend to be less restrictive than direct analysis using quasi-analytical solutions and have the potential to yield information about conductivity and water retention over a wide range in pressure heads from a single infiltration experiment. This report documents IDSfit, a computer program that enables the inverse estimation of soil hydraulic parameters using outflow data obtained from tension disc infiltrometers. The emphasis of IDSfit is to provide the necessary computational environment to analyze cumulative infiltration and water content data from field experiments. To facilitate this intent, the program permits the specification of non-uniform initial water contents, a flexible fit of near saturated conductivity that is not dependent on pre-defined functional expressions, the specification of multiple soil layers, and the inclusion of water contents into the objective function that represent volume estimates instead of point estimates. A graphical user interface is used to assemble input data required by the executable file. Detailed instructions and examples are provided for data input preparation and selecting optimization strategies.