HGL vs WSE

[SueP]

When reviewing detention studies, I typically see 2, 10, and 100 year WSEs. The one I'm looking at now provides the HGLs instead of the WSEs. Are they interchangeable?

 

[Engimental]

HGL = total fluid head - velocity head = elevation head + pressure head - velocity head.

Assuming a free water surface, then yes, HGL is equivalent to WSE (i.e., elevation head).