Time series Stage input

I have some confusions in using stage time series. Please help.


There is an option of using time series data for outfall stage. Should I include elevation of water or depth of water in this case.


For example,

invert EI =-5 ft

Outlet offset= 0

depth of conduit = 12 ft

depth of water ( stage)  =7 ft


Now, should I  input  stage at outlet = 7ft

or I should input with reference to Invert EI= 7-5= 2ft


I have the same confusion for initial depth of water in junctions. Is it just depth (7ft) or the elevation (2ft)




Thanking you  in anticipation.




E-mail me when people leave their comments –

You need to be a member of SWMM 5 or SWMM or EPASWMM - (not formally associated with EPA) to add comments!

Join SWMM 5 or SWMM or EPASWMM - (not formally associated with EPA)


  • Thank you Robert :).

    I was not aware of this blog when I started working with SWMM. But as it today, It is my first priority whenever any confusion arises in my mind regarding my modeling. And all credit goes to your timely and informative responses. I enjoy this interaction with you and I must say, I have been greatly helped by many of the posts in this blog.

  • Thank you for your interesting questions!   They always shed new light or help me understand better,  BTW, you can call me Robert.  I am not a Dr Dickinson but merely a Mr Dickinson and Mr sounds too formal as we now have a good dialog going  with your interesting questions.

  • Thank you Dr. Dickinson. I got the difference right now. Thank you  for your help.

  • If you have an outfall time series then the stage should be elevation and not depth


  • The initial water is depth and not elevation but at the outfall the fixed stage is elevation -  I admit it is confusing


This reply was deleted.