Yes. If you currently use Visual MODFLOW Flex, you will already have a 3D conceptual model that defines the geologic layers, properties and boundary conditions independent of the grid. To run your model with MODFLOW-USG, simply auto-generate the unstructured grid and then run the simulation. Visual MODFLOW Flex’s multi-model environment allows you to manage both your MODFLOW-2005 and MODFLOW-USG models within the same project, and both models can be easily compared side-by-side.
If your model currently exists in Visual MODFLOW Classic, you will need to import your model into Visual MODFLOW Flex before you can run the model using MODFLOW-USG.