I am trying to work out a system in which I need not do any manual data entry for Pre-development runoff Flows something where I can just process geometry data from CAD,C3D,GIS through some MAP3D overlay and join functions then export into SSA, and when I open the SSA subBasin object all those worksheets are filled out like magic, so that I have super accurate TOC and Q values. I've got a whole flowchart of how to roundtrip the data but before I go through the aggravation of testing it...


1. Does anyone have experiance with this?
2. What is the preferred Time of Concentration method in SSA for large predevelopment areas?
3. Is it better to calculate TOC in Civil3D catchments and export or is it better to export civil3d parcels and enter TOC manually in SSA?
4. can the channel sections exported from civil3D for HECRAS as a .geo file be imported into SSA as cross sections in a link of the irregular type? or should I process it through HECRAS then export as an .sdf?

ideally the only input done on an object by object basis would be setting the transitions between sheet/shallow/channel flows on the TOC line in the catchment object.