Once the desired sub-basin delineation from the DEM points has been defined, the basin boundaries can be converted to feature polygons. This is done by tracing the boundaries between sub-basins to generate arcs. After all of the boundaries have been defined the arcs are converted to polygons and the polygons assigned the appropriate basin ID.
The resulting polygon boundaries will be jagged because the arcs created for the polygons trace around each raster DEM cell. In order to make the boundaries appear smoother and more visually appealing you can redistribute vertices along a cubic spline. If you are using a 30 meter resolution DEM then the average length between vertices will be approximately 30 meters and it is suggested that you redistribute to about 100 meters spacing (be sure to turn on the cubic spline option). In general, redistributing to about 3 times the DEM resolution will produce good results.
Related Topics:
Defining Basins
DEM -> Stream Arcs
Computing Basin Data
Polygon Basin IDs -> DEM