Supercharging Intergraph Hydraulics
In 1992, Intergraph's Hydraulic Design Tools did NOT support surcharged gravity flow. My response when I learned this was "Well, we can't use InFlow in Florida. There we design the parking lot inlets to pond up to six inches to provide enough head. This is a show stopper." (I was new to Intergraph's solutions. I had been using the engineer's swiss army math knife: excel).
HEC-22, the (now) Bible on Urban Drainage, was not published at this point. We had a copy of the City of Austin's Drainage Manual, but basically we had our college Hydraulics Manuals and a whiteboard. We also had to figure out how to implement pumps in a steady-state InSewer (sanitary) program.
I think it was about a six weeks process of working on the whiteboard with the Water Resources Engineering Manager, waiting for the code, testing it and returning to the whiteboard. We got a good solution that made us market-viable for several years and versions (including Storm&Sanitary) until HEC-22 became the de facto standard, at which time it was incorporated into the code.