Groundwater Vistas (GV) is a sophisticated Windows graphical user interface for 3-D groundwater flow & transport modelling. 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 advanced (stochastic) version of Groundwater Vistas provides the ideal groundwater risk assessment tool. Groundwater Vistas is the first modeling environment for the MODFLOW family of models that allows for the quantification of uncertainty. Stochastic Groundwater Vistas includes Monte Carlo versions of MODFLOW, MODPATH and MT3D , Geostatistical Simulators SWIFT support, 64-bit support and more. The Professional version includes Groundwater Vistas Advanced + AquiferWin32, Winflow, GW3D, MODHMS support*, and GSFLOW support. The Premium version includes Groundwater Vistas Professional + SAMG Solver. GV displays the model design in both plan and cross-sectional views using a split window (both views are visible at the same time). Model results are presented using contours, shaded contours, velocity vectors, and detailed analysis of mass balance.