Modeling "pond" storage with two different layers

[Cap07]

I'm am modeling a bioretention planter that consists of a soil layer with a gravel storage bed beneath it (please see the attached image):

Layer 1 - soil mix, 40% voids, infiltration rate = 1.5 in/hr
Layer 2 - gravel storage bed, 33% voids
Subgrade - Native soil, infiltration rate = 3 in/hr

Is it possible to model the planter with one pond element and take into account the infiltration rate of each layer?

 

[psmart]

The media layer separates the two volumes so they no longer behave as a single pond. Since the stone storage is negligible in peak flow mitigation, we recommend that you include only the storage above the media, with the media as an extraction outlet. For details see

http://www.hydrocad.net/raingarden.htm

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[Cap07]

Thanks for your reply Peter. So are you saying to only model the pond storage with an extraction outlet, and ignore any storage provided by the soil media and gravel bed?

 

[psmart]

Correct. Please see the page I referenced for details.

Peter Smart
HydroCAD Software

http://www.hydrocad.net