Predictions of solute transport in the field are generally based upon convective-dispersive type transport equations. The one-dimensional form of this equation contains two parameters which must be determined beforehand. They are the dispersion coefficient and a distribution coefficient, the latter acounting for adsorption or exchange between the liquid and solid phases. Both coefficients can be obtained by fitting an analytical solution of the one-dimensional convective-dispersive transport equation to observed column effluent data. CFITM describes a non-linear least-squares curve-fitting computer model which may be used for that purpose. The program considers analytical solutions of the convection-dispersion equation for both finite and semi-infinite porous media.
The code comes with a user manual giving detailed instructions for data input preparation. Sample input and output files are also provided.
M. Th. van Genuchten. 1980. Determining Transport Parameters from Solute Displacement Experiments, Version 1.0. Research Report No. 118, U.S. Salinity Laboratory, USDA, ARS, Riverside, California.