Cxtfit is a computer software developed by the saline soil laboratory of the United States to study one-dimensional soil solute transport. Based on Levenberg Marquardt algorithm, cxtfit uses the function optimization method of nonlinear least square to fit the breakthrough curve of solute mixture replacement experiment, solves the model parameters, and predicts the concentration distribution of solute in soil with time and space. Cxtfit is based on the solute convection dispersion equation. The original cxtfit1.0 was developed and compiled by Parker and van Genuchten, and gradually improved into today's cxtfit2.0, which contains more equation analysis for different initial boundary value problems and generation problems. The software includes three different types of solute transport models: equilibrium CDE model, physicochemical nonequilibrium CDE model and stochastic flow tube model.

Parflow is an open source, object-oriented and parallel watershed scale model. It includes a fully integrated land flow with the ability to simulate complex topography, geology and heterogeneity, as well as land surface processes including land energy budget, biogeochemistry, and snow (through CLM). It can run on multiple platforms. Parflow is the result of a long, multi agency development history and is now a collaboration between CSM, LLNL, uni Bonn and UCB. Parflow is combined with mesoscale, weather code ARPS and NCAR code WRF.