Pond Not Assuming Infiltration

[Tori_B]

Hello everyone,

I'm very new to HydroCAD and have been having difficulties with it, the primary one being my pond doesn't want to infiltrate. I'm using a Pond to simulate my eight rain gardens in my design (since I can only use the school version of HydroCAD, we can only have 5 nodes). I'm using a catch basin with storage to model my rain gardens, since they're fairly large. I have my storage values correctly, but my culvert values are off, and it's probably why my Qin=Qout for my rain gardens, which isn't true. This is affecting the rest of my design as well. Any input is greatly appreciated. Thank you.

 

[psmart]

If you want to allow for infiltration, you have to create an exfiltration outlet.

Regarding the peak outflow, rain gardens generally do not have enough storage to produce significant peak attenuation. Their purposes is generally to handle pollutants during smaller rainfall events, which often comprise more than 90% of the annual rainfall. That's a good reason to use rain gardens. But a rain garden will tend to overflow during more significant events, producing little or no peak attenuation. And infiltration is generally too low to have much effect on these short duration high-flow events. So other measures are generally required to handle peak-flow mitigation for larger events.


Peter Smart
HydroCAD Software

http://www.hydrocad.net