roof drainage

[queque]

I have a 70 sq.ft. roof. Rational Equation provides a flow of 0.75 cfs.
I = 9.6 in/hr, Area = 7700 sq.ft. C= 0.9
I will install 9 vertical pipes on the roof, connect them to 9 horizontal pipes underneath sidewalks.

I am not familiar wiht methodology

 

[msquared48]

Not really sure what your question is here - your posted answer does not match your input for the rational equation, plus you show two different areas.

Mike McCann
McCann Engineering

 

[psmart]

for details on roof modeling please see

http://www.hydrocad.net/roof.htm