AutoCAD Civil 3D :: Catchment Area Enhancements

I wish to have the ability to define runoff coefficient regions of a surface (using parcels, closed polylines, aecpolygons, mpolygons, etc...) such that when a catchment area is created, the weighted runoff coefficient is calculated. For a corridor surface, the runoff coefficient can be specified by the link code used to define the surface (defined in the code set style).

These surface coefficients should continue through pasting operations, i.e. a final design surface should have the runoff coefficents from the various corridor and grading surfaces used to define it.

Currently, I have to manually calculate the weighted runoff coefficient by first determining grass, aphalt, roof, areas per each catchment area.