It could be the wetted perimeter or the Mannings number but my guess is that you probably copy paste something twice -js
What I would do is:
1 Built a duplicate of the City model. Making sure the cross sections extend all the way to your structure eventhoug water doesn't get there. Run the...
I am assuming
-There some kind of existing sheet flow going and some flow makes it to the pond and some don't; otherwise, if you are matching 50% of the existing, there is no way the pond gets overtop.
-You have the ability to take the flow around or away from the pond once you intercepted so...
