HydroCAD Exfiltrate Volume
HydroCAD Exfiltrate Volume
(OP)
Hi All!!
Is there a way to exfiltrate a volume from the pond routing instead of the given parameters (conductivity, flow and velocity)?
Background: We have computed our net runoff volume that needs to be infiltrated in our ponds. The volume reduction is limited to 6 hours of infiltration only. As far as I can tell, HydroCAD uses the conductivity rate over the entire storm duration and results in higher infiltration volumes than targeted.
Thanks! Lisa
Is there a way to exfiltrate a volume from the pond routing instead of the given parameters (conductivity, flow and velocity)?
Background: We have computed our net runoff volume that needs to be infiltrated in our ponds. The volume reduction is limited to 6 hours of infiltration only. As far as I can tell, HydroCAD uses the conductivity rate over the entire storm duration and results in higher infiltration volumes than targeted.
Thanks! Lisa





RE: HydroCAD Exfiltrate Volume
However, you might be able to induce the cutoff by routing an exfiltration outlet (perhaps an orifice) to a link with a manual elevation table. The table can be used to define a tailwater that suddenly increases after 6 hours, thereby turning off the exfiltration outlet.
FYI, there are other outlet options that could be used to start the exfiltration at a specific time (including a pump, dam breach, or siphon) but getting the flow to stop as the WSE in the pond is still rising is more difficult. In reality, this just isn't going to happen.
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: HydroCAD Exfiltrate Volume
RE: HydroCAD Exfiltrate Volume
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: HydroCAD Exfiltrate Volume
RE: HydroCAD Exfiltrate Volume
I know it's generally futile to argue with the regulations, but something doesn't seem right here.
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: HydroCAD Exfiltrate Volume
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: HydroCAD Exfiltrate Volume
You're right psmart! I don't argue the regs, I just try to bend to them. HA!
RE: HydroCAD Exfiltrate Volume
For an Infiltration Trench, section 6.4.4 states "*Infiltration Period is the time when bed is receiving runoff and capable of infiltration. Not to exceed 72 hours. "
The trench is used as an example in Appendix D where they "assume 6 hours". If one has infiltration testing that saturates the soil and then runs for a longer time, one should be able to justify periods supported by the site testing (up to 72h).
For an Infiltration Basin, section 6.4.2 states "*Infiltration Period is equal to 2 hours or tne time of concentration, whichever is larger. "