Stretching Time of Concentration

[localgov]

The "hydraulically most remote point" has a tendancy to be misused to the designer's advantage and local government's problem. Is there a reasonable engineering reference relating post-development toc flow path relative to the developed basin?

 

[cvg]

don't know of one, however this is not the only "knob that can be tweaked" to estimate lower runoff. And it works both ways, designers and agency reviewers can both play this game to there advantage.

http://www.stormh2o.com/SW/Editorial/Voodoo_Hydrology_37.aspx

 

[beej67]

A good thread, with some good links:

http://www.eng-tips.com/viewthread.cfm?qid=236624

Check the excel spreadsheet that's hosted a few posts down.

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

http://www.campbellcivil.com

 

[fel3]

I find that the best way to stretch the Tc is to get the water moving at relativistic speeds.

If I have a drainage area with a small but long "stringer" I ignore the stringer for Tc but not for A. It's a judgment call as to what constitutes "small".

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