SWCC Fit Methods

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The SWCC Fit dialogs contain all parameters necessary to define a mathematical representation of the soil-water characteristic curve which can be used for the current numerical model. Press the Properties button beside each fit method on the SWCC dialog to open the corresponding SWCC Fit dialog.


SVSOILS provides the use of the fit equations described in the following sections. Each fit method uses a non-linear least-squares regression algorithm to optimize equation parameters. Alternatively equation parameters can be entered manually for any particular fit.


It is up to the user to determine the best-fit method to use for a typical model. Each of the fits of the SWCC presented in SVSOILS was developed in order to overcome a certain limitation in the general methodology. The fitting of more equation parameters generally lead to a smoother representation of the SWCC but at the expense of increased computation times and the added complexity of fitting additional equation parameters. A review of some of the fit equations is presented by Sillers (2001) in a paper that can be downloaded from the Support & Training > Research section of our website.