How to unsnap contour lines from my lake boundary

[JenniferDuBay]

Hi all,

   I am trying to create a lake contour map for the first time. I have used a number of different spatial analyst tools, but spline seems to come the closest to what I'm looking for. My main problem is the contour lines snap to the boundary so the lake shore looks like a wall (topographically).

Here is the north side of the lake as an example and a zoomed in section of the shoreline to show you what the contour lines do:

  

This is what I want it to look like:

Any suggestions would be much appreciated.

Thanks a bunch!

  Jenny