HYDROCAD Affect of groundwater depth - Infiltration Basin 1

[TheEnginerd]

Hello All,
Hoping you might be of assistance. I have designed an infiltration basin in HydroCAD.
For the "Exfiltration" Outlet, i have selected the "Conductivity" type as we have a known conductivity of 17.25 inches per hour. Previously, the basin bottom was 2.5 feet above the groundwater elevation. New soil tests have eliminated this prior (inaccurate) result, and new groundwater elevation is 10 feet lower.
Upon revising the groundwater elevation to the lower elevation, the basin fails. This is not intuitive to me. Would not an increased depth to groundwater and thus increased void space to accept the water from the basin help with the basin design? or am i totally missing something?
Thank you.

 

[psmart]

When using the HydroCAD Conductivity option, the flow is determined using Darcy's law, in which the flow is inversely proportional to the media thickness. This means that the flow will decrease at the distance to groundwater increases. For details please see

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

Complete equations are provided in the HydroCAD Owner's manual.



Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[TheEnginerd]

thank you Peter. I appreciate your help as always.
-Andy