MANPIP
04-09-2014, 08:20 PM
Post: #15
 Jerussi Junior Member Posts: 20 Joined: Apr 2014
RE: MANPIP
Yes Y would be calculated and the corresponding V too. In the specific example I gave you to solve for the Q, yes Y is also calculated and in that example y is equal to D as it is solving for full flow.

Now if I would enter N=0.013, Q=12 (CFS), D= 21 (inches), S=.01 (for 1%), Y= no input the program will solve for Y and V. The answers should be something close to Y= 1.14 feet or 13.68 inches and V = 7.26 Ft/sec. In this case Y is not equal to D.

I have attached a storm sewer design spreadsheet we use in our site plans. This should show the formulas in the cells that are computed as examples of the calculations - I hope it helps some. Ignore the elliptical pipe sizes as I am only concerned with circular pipe. This is not as useful as the other attachement described below.

I have also attached a document "080_14320.pdf" with alot of information on the Manning's equation with all the formulas. In this document they call "Y" out as "h". This is a good reference.

Attached File(s)