This section briefly describes some of the technical aspects the WEPS program implementation and the interaction between the WEPS interface, main program, databases, and the science model. The WEPS 'science' model refers to the computer code and executable program that performs the actual calculations of field conditions and erosion processes for a simulation run. The science model consists of the main program and the submodels. The databases are utilized by the interface and the science model for model input. The interface can be thought of as a 'shell' around the science model from which the user can simply provide inputs to the model and read outputs. A detailed description of how to operate the WEPS User Interface is described in How to Operate WEPS.