Development of MODFLOW-USG: an un-structured grid version of MODFLOW

MODFLOW was revolutionary when it was first unveiled by the USGS in 1988, and since then it has been the most widely used groundwater flow modeling program in the world. MODFLOW’s simulation capabilities have evolved substantially since its initial release and it has been an inspiration for more comprehensive analysis simulators including surface-water/groundwater interaction models (e.g., GSFLOW, SWF, MODHMS, ISGW), flow and transport analysis simulators (e.g., MT3D, MODFLOWSURFACT, MODFLOW-T), and saltwater intrusion models (e.g., SEAWAT).