I agree with Meadowlark. I have an above ground spillway lined with stone in my pond that has a dyke and it's foolproof unlike a pipe that regardless of you do -- as in collars -- may cause you problems.

I've always been a believer of "keep it simple stupid" and "if anything can go wrong it will."

I raise my waterlevel going into winter by dumping in a wheelbarrow of clay and then dig it back up in spring to resume the flow. Doesn't take much.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.