How would someone model 3 pipes side by side to be used for a road crossing over a small creek? I'm looking at using (3) 36 inch pipes. Do I just create 1 pipe and then change the discharge multiplier?
Is this a question concerning HydroCAD? If so, please post in the HydroCAD or Storm/Flood forums. And yes, you can use the discharge multiplier for that purpose. Click help for details...
Sounds like a culvert design inquiry. See FHWA HDS5 for guidance on hydraulic analyses for culverts. FHWA has a program HY-8 that will compute hydraulics of a culvert.