Hydraulic conductivity, shear strength, chemical diffusivity, water storage, unfrozen volumetric water content, specific heat, and thermal conductivity are all functions of the soil-water characteristic curve.
Considerable judgment is required to develop the relationship between soil property functions.
The judgment rules can be enforced using a knowledge-based system based on observations and empirical relationships amongst soil property functions. Access provided a suitable environment for combining the user interface, knowledge base, database, and query system. The system allows the estimation of many complex soil properties while reducing both time and cost requirements. Theory governing the behavior of unsaturated soils has been available for several years and has shown that the soil-water characteristic curve is the central relationship describing how a soil behaves as it desaturates. Research has shown that empirical relationships can be used to describe unsaturated property functions related to the soil-water characteristic curve.