[jhmiller]

I have a pretty good handle on most typical situations using the software, but have two more complex situations arising. Can anyone tell me how I can effectively model the following situations:

Situation 1.
I have overland flow paths that lead to a detention basin intended to be used for first flush quality improvement. Located in this basin is a manhole with a frame and grate 6" above the basin floor. As the basin fills up, it is intended that the excess flow be relieved by the frame and grate. However, due to upstream pipe connections to the manhole and the downstream system being undersized, I actually end up with surcharge through the manhole in larger events.
MY SOLUTION: I added a detention basin and routed the overland flows flows to the basin. I connected the basin to the manhole using a orifice (bottom) and set the crest elevation appropriately. For the manhole I allowed surcharge and set the ponding area to match the footprint of the basin.
MY QUESTION: The top water elevations for the basin and manhole don't match of course. How should the model be set up so that the levels interact with each other?

Situation 2.
From above, lets say, my basin can't handle the surcharge volume and I want excess flow above a certain elevation to flow out of the basin and into an earthern channel.
MY SOLUTION: I converted my manhole to a diverter with weir diversion to the earthern channel.
MY QUESTION: Again because the basin (with orrifice to diverter) and diverter (needs to divert flow from basin with its own weir) are two seperate elements, I am not sure that the model is accurate.

I know that this is long winded and confusing but, if anyone has any thoughts, please let me know.
Regards
Jesse