A beta-test version of TETrans (acronym for Trace Element Transport) is presented which models the movement of inorganic solutes through the vadose zone under transient-state conditions. TETrans is a complete software package consisting of an interactive tutorial, user's guide and applications software. Both IBM-compatible and Macintosh versions are available to users. TETrans is specifically designed to be intuitive in its operation and require only readily available input parameters in order to enhance its utility as a real-world applications tool for transport modeling.
The transport model utilizes a mass-balance approach to determine solute concentration distributions over time and solute-loading to the groundwater. Several modeling options are available for simulating such transport-influencing factors as plant-water uptake, hydraulic bypass and adsorption. In the Macintosh version, TETrans makes full use of the Macintosh interface to enhance the user-friendliness of the model. All functions are available from pull-down menus, and simulation results are displayed in text and graphic windows.
Test data are shown which include a comparison of simulated and measured results for the movement of chloride through a soil lysimeter column over a 900-day study period. Excellent agreement is found when a single parameter for bypass is used. TETrans is distinguished from other transport models in the straightforward manner in which it handles the exacerbating problem of hydraulic bypass. The hydraulic bypass parameter, termed the mobility coefficient, is determined from simple chemical analysis of chloride in the soil solution through the soil profile following the application of a plug of chloride in the irrigation water. The mobility coefficient reflects the volume of soil water which is not subject to piston displacement