Modeling discharge questions

[Cadi1]

I am modeling stormwater runoff in a quarry and want to use the ten feet of shot rock below the floor as storage for runoff. Assuming the shot floor has a limited void space (10%) for storage,what would be the best way to model the discharge to a detention basin on the quarry floor? Also, should I model the overburden above the quarry floor as one area with a Tc to the quarry floor and the quarry floor with a Tc=0, separately?

My concern is the effect that stormwater runoff from the quarry has on downstream structures. Therefore I need to begin the routing at this basin on the quarry floor.

Any ideas would be appreciated.

 

[psmart]

In general, you would define the outer storage volume (the total volume of shot rock) and then set the void space (10%). If there is additional storage that will act as part of the same level pool (your detention basin?) then you can use an additional storage line (in the same pond) to define this volume. You can then define the outlet control(s) that will regulate the discharge from the overall "pond".

Rainfall that falls directly on the surface of a pond is often modeled as a separate subcatchment with Tc=0 and CN=98. But if the pond surface is a small fraction of the total area, you could include it as a sub-area in an adjacent subcatchment.