SSA - where flow coming from?

[dshklovsky]

I have ~ 150 structures model, it runs OK, but in several pipes something strange is going on.  Say, flow coming through the pipe A into the inlet structure and then through pipe C.   I have 70cfs in pipe A, 1 cfs coming into the inlet B over the land from subbasin,  7 cfs coming bypassing inlet uphill - why it shows 295 cfs in the pipe C?

Also - sometimes, not always - I have very different results running same model by SSA2012 and SSA2013.

Any explanations?

[Hidden_Brain · Accepted solution]

you may want to check the "ponded areas" fo ryour inlets. I have had this "flows-not-matching-up" problem happen to me in the past, and setting the ponded area to 100 has fixed it. look into the following discussion:

http://forums.autodesk.com/t5/AutoCAD-Civil-3D-Stormwater/total-inflow-and-vs-catchbasin-flow/m-p/33...

good luck!

[Hidden_Brain]

i think you accidentally replied to the thread that i sent you instead of this one, although they both are on the same topic. to answer your question, 100 is the magic number that has saved me at all instances with SCS. i do not know what the logical interpretation of that number is to be honest. also, i found that this setting does not have a big impact on rational method models, but note that a user on the other thread did make mention that it seems to affect not the spread width but the depth.

If I adequately answered your question, please remember to mark as solution so that other members can benefit from it.

[dshklovsky]

Well, 100sqft worked in the one area and doesn't work in the another; should be something else ..
Thank you!

[Hidden_Brain]

if you want, upload your model here, I would be more than happy to take a look and see if I can offer any additional help!

[dshklovsky]

I do not understand why flow increases so dramatically after DCI59?
Thank you for help,
Dmitry

[Hidden_Brain]

did you intend to attach your model here? I do not see an attachment to your recent post.

[dshklovsky]

Sorry, did it go through now?

[Hidden_Brain]

do not see any attachment to your post, maybe try renaming your .spf file as .txt and upload it here.