Here's some pictures I took from the spillway.  The spillway is actually a separate dam between two hills (mountains in OK).  What they call the dam is an earthen structure further up the road between the next mountains tops.  The power house is at the dam proper.  The dam is quite a bit bigger than the spillway which you see here.

These pictures are taken from the top of the spillway structure.

Looking out at the lake from the spillway.