Infraworks 360 has many nice features that aid in the preliminary/conceptual design process. One of these handy features is the Watershed tool. It allows us to quickly delineate a drainage basin; even when we have little or no data to start with. The Model Builder command within Infraworks can pull a preliminary surface from a USGS data source and allow you to immediately start your basin work. The bonus is that we can bring our new basin directly into Civil 3D for continued analysis.
Check out the video below to see the Watershed tool in action.