If I had to guess, I would say it is some sort of flow meter / distribution box for the building's septic system. Judging by the water mark on the face of the v-notch weir I would say the flow is from the 4" to the three-hole side. The three pipe may lead to leach lines. The vertical PVC is...
Thanks gbam. Your confirmation of #1 and #2 was a big help. I didn't completely follow the response to #3 - specifically losses through access hole - but I will dig back into the H22 manual as you suggested. For the prelim design I simply kept the pipes deep enough that the incoming pipe's EGL...
There are a lot of questions to that design that seem super hard to assess - what is the rate of overtopping with a storm surge, what will be the tailwater level when the weeps are draining, etc. It seems it would be most prudent to eliminate those questions and design the wall assuming the...
I'm attempting to manually use HEC-22 to prepare a HGL through a section highway stormdrain. Attached is a PDF of the preliminary profile. The stormdrain discharges into the side of a large box culvert that is flowing supercritical. Furthermore, all of the pipes upstream are flowing...
