The MREP uses Subversion as its version control system [20] . Subversion is a free, open-source application that is licensed under the Creative Commons Attribution License (see http://svnbook.red-bean. com/en/1.0/). The MREP also includes a Graphical User Interface (GUI) application that allows the user community to use the MIDAS models more easily. The GUI interfaces with Subversion, the database management system, and the computer environment. The GUI allows the user access to the model source code, provides an interface to input data sets, permits results to be viewed directly or downloaded to a user workstation, and provides a mechanism to submit the models for rerunning.