Tc for pre- and post-development

[Scott Horowitz]

A site project that I am working on appears to have the pre- and post-developed time of concentration unaffected, either in time or flow path, by a proposed building location and site work. How does one address this scenario? I am worried that I will under-design the detention pond...

any thoughts are appreciated.

Thanks,

Scott

 

[beej67]

I infer that the most hydraulically remote point, and subsequent flow path, has not changed between cases?

You might consider breaking out the proposed development watershed into two basins, one for the development area and one for the rest of the watershed.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[Twinkie]

As stated above, if you believe the additional building area may have an effect on the site hydrology, break the drainage area down further.

What is the order of magnitude between building : drainage area?

If you are adding a 1000 sf barn on a 200-acre farm the impacts are negligible. Same barn on a 1/2 acre is a different story.