Getting too high Hydraulic head values in 3D groundwater flow modelling

Hello,

I am trying to develop a 3D groundwater flow model. Maximum elevation is 36 m and minimum is 0 for my domain area. I am setting a hydraulic head boundary condition of "Elevation -1/4.Elevation" on highly located hills. When I run the model, I get very high values of Hydraulic head (max. 2986 m). Does anyone know why do I get so high values? My area has three geological layers. Bottom layer is bedrock (Kxx and kyy=10 raise power minus 12), middle and top layers have a combination of sand, clay and bedrock (kxx and kyy ranging from 10-7 to 10-12).  Any help in this regard is highly appreciated in advance. Best regads Imran

Usually, high recharge and very low conductivity cause high heads.However, need to confirm with the boundary conditions. If im not wrong, seems downstream area of your model is closed, this could be a issue

There are numerous things that could be the problem, and without more information, advice might not help.  Is the model transient or steady-state? what mode are you running...confined, phreatic, variably saturated? What are the other boundary conditions in the model (in/outflow on top/bottom, wells, etc)? What is the initial head of the simulation?

Pete