I suggest no spillway screening unless you have grass carp. If your pond has adequate bottom structure and cover for fish, there is no need for a screen. If the pond was designed properly, to accomodate a hundred year flood, a screen isn't necessary.
If you have grass carp, consider screening downstream, away from the spillway, if possible. If not, absolutely do not have the top of your screen higher than the lowest point of your dam.

Teach a man to grow fish...
He can teach to catch fish...