Scientists conduct experiments to understand natural processes. From this understanding they create mathematical models that help to extend this knowledge to new areas and new conditions. Models are generally made for a specific purpose. They always involve simplifications. The model developer has a responsibility to enable the user to understand these simplifications. The model user must select a model which is consistent with the system of interest, the answers required, and the data available. 

An overview of models, documentation, and educational material is available here

Water and Chemical Movement in Unsaturated Soils: CHEMFLO-2000

• Finite difference solution to Richards equation for transient water movement in unsaturated soils  

• Finite difference solution to convection dispersion equation for transient flow of chemicals in soils  

• Supports multi-layered soils

• Utilizes improved numerical methods

• Extensive graphics

• Excellent tool for examining sensitivity 

• Runs on Windows, Linux, and Mac OS X platforms

• Replaces previous version of CHEMFLO software

Chemical Movement in Layered Soils: CMLS

• Management model  

• Parameters are readily available  

• Employs Monte Carlo simulation to deal with uncertainty in future weather  

• Built-in graphics in interactive model  

• Tool for evaluating differences due to spatial variability

• Batch model for use in large studies and GIS applications