Drain Elevation Not Working

[Hydrology 3]

I am setting a drain with a specific elevation in a MODFLOW run, but the final gw elevation for the cell that the drain is located in, is not the same as the elevation that I set for the drain.  It seems to vary depending on the hydraulic conductivity that I set for the layer that the drain is in.  For low layer conductivities, the final drain elevation in the cell is close to the elevation that i specified for the drain, but for higher layer conductivities, the gw elevation in the cell can be several feet higher than the specified drain elevation.  How can I get the drain to force the elevation in the cell to what I specify?

[Rob Virtue 0]

What conductance value are you using for the drain and what are the Kh & Kv of the high conductivity layers? A higher drain conductance is required to fully drain a higher conductivity layer.