OpenRoads Drainage Design is tightly integrated with OpenRail/OpenRoads/OpenSite geometry, surfaces, and corridors.

As an example, a curb inlet can be placed so that it automatically reads the proposed corridor terrain elevation and longitudinal and transverse slopes.  It can read the roadway information and determine gutter flow paths and calculate and spatially depict gutter flow depths and spreads. 

Updates to the roadway geometry, including changes to, say, superelevation can be automatically read and the calculations adjusted.  

In short, the drainage designers are heavily dependent on your work and any changes you make.  It is important that you communicate with the drainage team when significant changes to your design occur.

As they change the drainage design, a refresh (or reopening) of the reference files will update what you see in your model.