Locating outfall

[boblott]

I have to discharge the surface run-off from a land into existing Storm line (12”) in New York City, but I can’t locate the outfall. A there a check list. Much appreciated. Bob

 

[Ryb01]

Bob,
Have you considered speaking with city officials to aid in your search?
If there is no outfall it may be best to connect to an existing storm sewer network in your area vs creating another outfall. This method is generally preferred with the governing agencies.

Hope this helps.

 

[gbam]

Have you reviewed the As-Built plans in the area to determine where the existing line is?

 

[sam74]

You could put an inspection camera in the pipe and crawl the length of pipe until you find a manhole that has been covered or whatever is there. That way you'll have a distance from your input point and a pretty good idea of the direction.

 

[boblott]

Good news I found a 12 ft circular sewer line nearby. I read once I have to tie the proposed HGL to the existing HGL at point of connection. How would I achieve this. Maybe, by putting a camera inside to see the highest level water has reached inside the pipe in the past.

 

[cvg]

Unless you have better information, assume the 12' pipe is flowing full and use that as your starting HGL.

 

[francesca]

I know there is at least some SWMM modeling of storm sewers in Manhattan around subway stations where they had experienced flooding. Talk to the City and find out if your area is modeled. I would be surprised if they did not have at least a good inventory and know where flooding occurs. You would show your HGL tying in by adding your proposed lines to an existing model.

 

[CPENG78]

Boblott,
Along the lines of the comments from CVG and Francesca, starting HGL information should be obtained from the agency that oversees the system (i.e. Previous studys, Agency Computer Models, previous project improvement plans). If you get lucky with your research, HGL data is sometimes plotted onto storm sewer improvement plans. I'm in the west coast and when there is a lack of better data, some agencies allow you to to assume the pipe to be half full. I personally prefer CVG's assumption and assume the pipe to be full. I would discuss it with the agency official/plan checker to see what assumption they would feel confortable with, specially if flooding or any drainage issues may have been observed.

 

[tsgrue]

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Smoke and dye tracers.

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tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

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