multiple flows to one outfall
multiple flows to one outfall
(OP)
Hello. I am looking at multiple ponds, some of which are interconnected but then at the end of the line I have like 3 or 4 outflows from those ponds going to one outfall so when I'm looking at how much water is being introduced to that single outfall how do I combine those flows? I can't simply add them all together right? but they are not connected, it's like 3 pipes discharging at the same point in a river and I want to compare pre- to post-development and I have the flows out of each of those outlet pipes but how do I combine them to say "this much is entering the river at this point" ?? Thanks in advance for your help.





RE: multiple flows to one outfall
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: multiple flows to one outfall
RE: multiple flows to one outfall
The scenario sounds like a typical hydrologic pond routing exercise; unless, the downstream conditions can reverse flow. Then you will need the software like ICPR or the like to route the hydrographs through the basins.
RE: multiple flows to one outfall
It was hydrocad but I guess I was asking a more general hydrology question - it's not proper methodology to just add them all up to say that's the flow that's coming into the outfall, is it? WE're not talking about volume, I could see adding up volumes but adding up flows oversimplifies things.
RE: multiple flows to one outfall
RE: multiple flows to one outfall
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: multiple flows to one outfall
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: multiple flows to one outfall
One more Question to you guys on this subject- what would you do without a computer program - like by solving by hand - how would you figure out cumulative peak flow for a post-development condition when the goal is to compare pre-development to post-development? My coworker suggested breaking up the pre-development in the pieces that you broke up the post-development and doing a new pre-development peak flow for each of those areas to compare to the separate post-development peak flows. Do you agree with that?
RE: multiple flows to one outfall
As for doing this stuff by hand...I did a small watershed once or twice in school, I couldn't imagine doing what I do now by hand.
RE: multiple flows to one outfall
if you did the TR-55 graphical method, it only gives you the peak so you could only add the them together, which yields a conservative combined peak flow.
RE: multiple flows to one outfall
So say your hydrographs are in one minute increments. In order to find the total flow 93 minutes in to your storm, you find the flows of each of those hydrographs 93 minutes in, and sum them, and that's the total flow 93 minutes in to your storm. You do that again for each time step in your storm. Obviously, this is a task for spreadsheets, if you're doing it by hand.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com