I can't seem to confirm the discharge table that hydraflow produces in hydraflow hydragraphs. I think I understand the equation itself (it's been a while since I took hydraulics), but can't understand where I'm making my error (if I am). Normally I trust the stage/discharge curve that hydraflow produces, but the City Engineer is asking me to confirm the values by hand and show them on the plans. Is there a link to an detention pond example that shows how a curve (the outflow values) was generated (confirms the discharge table at various elevations)? The equation is on page 85 of the users manual.
Try going to the table tab under ponds and hit the little plus on the lower right to expand the table. Print table.
What C value are you using in the manual calculations? It is normally around 0.6 for orifices.
Are you taking into account the back water from the lower pipe?
Can you post a pdf of your pond outlet configuration?