I've modeled underground voids and lakes in FEFLOW using the method you
describe. I know of no better approach in FEFLOW. There are modules
for MODFLOW that could be adapted using the IFM.

These references may useful:

Anderson, M.P., R.J. Hunt, J.T. Krohelski, and K. Chung. 2002. Using
high hydraulic conductivity nodes to simulate seepage lakes. Ground
Water 40, no. 2: 119-124.

Cheng, X., and M.P. Anderson. 1993. Numerical simulation of ground-water
interaction with lakes allowing for fluctuating lake levels. Ground
Water 31, no. 6: 929-933.

The large-K/Sy=1 approach seems to work as well as the fancy lake
packages developed for MODFLOW and other models.

Pete

bbarnett40 wrote:
>
> Has anyone had experience in using FEFLOW to calculate water levels in
> surface water bodies?
>
> Usually surface water bodies are included in groundwater models as head
> dependent boundary conditions. In other words the water levels in lakes
> or ponds are specified in the model input. However in many instances
> it would be useful to use the model to caluclate the water levels in
> the lake, pond or void. In the past we have addressed this problem by
> including the size and shape of void in the model grid structure and
> defined hydraulic parameters representative of a surface water body (ie
> extremely high hydraulic conductivity, storage of 1.0 and recharge
> defined as the excess of rainfall over evaporation) to the volume of
> the void.
>
> Is there a more sophisticated solution available in FEFLOW?
>
> Cheers