Depth of Flow 2

[beastmodeactivated]

Howdy,
I am an intern working with a water district this summer. I am working on an audit of the sewer system in our town and I am stumped. My first calculation is to find if any of our lines are running above maximum capacity (1/2 full for 12" diameter and less; 3/4 full for 15" diameter and larger) I was told to use manning's for this, but I can't seem to contort the equation to give me d/D. Tips?

Sincerley,
Daniel

 

[beastmodeactivated]

cr1973,
Thanks for the advice, I have previously taken your points into consideration and asked the operators of the sewer department to give me info. from the field. The operators checked a system of pipes for flow and I calculated the same system of pipes and I came up with a close to exact calculation, the sewer was running 2" deep and I calculated 1.96". Groundwater doesn't seem to intrude so much here, based on what the operators have told me, and my usage figures are not exactly conservative. Also after I run a spreadsheet on peak flow in normal weather conditions, I will be running a test on flood conditions because my area is prone to flash flooding. So far in the system I have only found one area to be over capacity that the operators have actually seen surcharge beyond the outgoing pipe. There are other problem areas because maximum capacity for most of our system is .5 d/D. I agree with you completley about water intrusion and thankfully the information from the field seems to confirm the consistancy of my figures.

 

[beastmodeactivated]

There's the link to my new post with the Excel file, I have some work to do on the quattro pro file for now.

http://www.eng-tips.com/threadminder.cfm?pid=770