The tables for soil hydraulic properties are linked to a database and some special functions are given to these tables compared to standard tables in the model. Upon resetting (using the Reset key in the tab dialog menu) the values in this parameter table may be either created or retrieved from the database. The values are added to the parameter tables ending with “measured horizons”. These values are interpolated over the soil profile to fit model compartments (see “Common Characteristics”). The result is shown in the tables ending with “model boundaries” or “model layers”.
If the hydraulic conductivity measured horizons table is being edited, the ‘Estimate’ key opens an additional dialog box that enables the saturated conductivity to be estimated from the textural composition of the soil.
If the water retention measured horizons table is being edited, the ‘Estimate’ key allows an estimate of four coefficients in the retention function to be made. The wilting point is always estimated from the clay fraction whereas the other three can be estimated either from the texture or from the water retention points. The estimation based on the water retention points are made by least square fitting and may be restricted to an intermediate range of pressured head that can be specified in the dialog fields. Note that the r2 value for the regression is given in the listbox together with the coefficient values estimated.