GWF = GroundWater Flow
- MODFLOW-2005 — the GWF Model contains revisions of the commonly used flow packages, stress packages, and advanced stress packages
- MODFLOW-NWT — the GWF Model supports an optional Newton-Raphson approach for water table aquifers
- MODFLOW-USG — GWF Models can be developed using regular MODFLOW grids or unstructured grids
- MODFLOW-LGR — any number of GWF Models can be specified for a single simulation; these GWF Models are tightly coupled at the matrix level
- MODFLOW-CDSS — multiple stress and advanced stress packages of the same type can be specified for a single GWF Mode
Excerpt: https: //www.usgs.gov/software/modflow-6-usgs-modular-hydrologic-model