Groundwater Vistas (GV) is a sophisticated Windows graphical user interface for 3-D groundwater flow & transport modeling. GV couples a powerful model design system with comprehensive graphical analysis tools. Developed by the author of ModelCadTM, GV is a model-independent graphical design system for MODFLOW MODPATH (both steady-state and transient versions), MT3DMS, MODFLOWT, MODFLOW-SURFACT, MODFLOW2000, GFLOW, RT3D, PATH3D, SEAWAT and PEST, the model-independent calibration software. The combination of PEST and GV's automatic sensitivity analysis make GV a powerful calibration tool.