Recent content by psmart

HydroCAD outlets are inherently 1-way devices, automatically behaving as if a 1-way valve were present.  So there is nothing special you need to do to model a flap gate - just define the outlet (such as an orifice or pipe) as usual. 

...then check the warning messages.  If you see a reverse-head message, then you know the flap valve is actively blocking the reverse flow.  But if there is no reverse-head warning, it means the flap valve would have no effect on the system, because the flow is always in the same direction.

All HydroCAD outlet devices are inherently 1-way devices.  HydroCAD will issue a warning message if a reverse-head condition occurs at any device, but no flow will occur in the reverse direction, as if a flap gate or other 1-way device were in place. So if you trying to model a culvert with a...

When you use a zero-storage pond with a culvert outlet, you are performing a complete culvert analysis including inlet losses, barrel friction, and tailwater effects.  Since there is no storage at the inlet, your will always get Qout=Qin.  However, the simulation will tell you the headwater...