Flow splitter modeling

[PaEngr]

I have an incoming flow from my pond into an outflow control box (1) that has a weir wall (A) within, with a top set to 2-yr ws.

In Box (1), downstream of weir (A) is a 2nd weir wall (B), that has top set to 50-yr elev, and has an orifice opening on its lower elevation.

The 2-yr inflow chamber water is piped-flowed out of box (1) and thru a separate WQ structure, and cleaned water piped back into the upper side of weir (B).

On downstream side of weir wall (B) is an exit pipe.

I can do a simple pond node modeled for Box (1) using its discharge pipe as device 1, and Weir wall (B) and its orifice both discharged into device 1.

But, I would like to add the Weir wall (A) to the node, to document the quantity of water being directed thru the WQ unit. How is this modeled?

 

[psmart]

You would probably need to model the space upstream of wall (A) as a separate pond. But then you'll have to deal tailwater issues. I would simplify the model rather than trying to include all the details of the WQ unit. Unless it provides a large storage (detention) volume, the WQ unit isn't going to alter the overall hydrograph going through the system. I would ignore the WQ unit and just use weir (B) and it's orifice.