I have been using SSA to design stormdrain system and swm basin on one of my projects and we are finally ready to submit to the review agency! In the stormwater report, I have few sentences about SSA program, in which I have written that it solves the complete St. Venant Equations and accounts for backwater effects, etc. Now my manager wants me to find out more about St. Venant Equations that the program uses. I tried to find it in the manual but it doesn't have the actual equations. Can someone please help me with this?