I'm using a StormTech chamber system for a stormwater detention system. My outlet pipe is connected at a chamber end cap. The question I have is, what is the best way to model the outlet in HydroCAD?
You could put an orifice plate over the culvert inlet: Assuming that device #1 is the culvert outlet, define the orifice as device #2, and set the orifice routing to Device #1.
See previous post for further details and illustrations.