The first version of the framework focuses on numerical solutions, numerical models, and numerical exchanges. The primary framework components include the simulation (or main program), Timing Module, Solutions, Models, Exchanges, and Utilities. The framework is written in Fortran using a modular object-oriented design. The report describes a new MODFLOW framework called MODFLOW 6 that is designed to support multiple models and multiple types of models. Often times, there are incompatibilities between these different MODFLOW versions.
Growing interest in surface and groundwater interactions, local refinement with nested and unstructured grids, karst groundwater flow, solute transport, and saltwater intrusion, has led to the development of numerous MODFLOW versions. MODFLOW is a popular open-source groundwater flow model distributed by the U.S.
