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Underground Detention - HGL

I am designing an underground detention system consisting of 3 x 1131LF 60 inch pipes.  The reviewer is asking for a profile of the HGL in the pipes with each inlet into the UGD (see his requirements/questions below).

  1. A traditional profile showing the HGL in the long pipes for the 2-, 25-, and 100-year storm event peak flows, accounting for inlets/lateral inflows.
  2. A stage-storage-discharge table, accompanied by a profile of the upper and lower range of WSEL’s in the long pipes (if static, we would expect this to show a conservative, or lower, storage volume at a given time than the profile where the HGL has a friction slope)
  3. Alternatively, the long pipes could potentially be modeled simply as hydraulic elements with flow routing instead of as a pond element.

My question is that profiling the detention pipes accounting for inlets/lateral flows doesn't seem realistic.  If this was a surface pond the max WSE would be used as the downstream for each of the laterals. Is there a printout I can provide to him that would answer his concerns? Per his comment #3, isn't the underground detention already modeled as a pipe hydraulic element since the model has the pipe size, slope, and tailwater information?