Thanks for the comments and suggestions, some things I have not thought of before. Such as if I pull 4’ of muck out where does it go. That’s 8 acres of muck 12" deep. I like the idea of raising the dam but it’s not feasible since the water would back up into the neighbor’s driveway.
As for the trees on the back of the dam I’m going to leave them for now. I think I may add about 3’ to 5’ width to the inside of the dam so that should help with the root issue. I have an arborist scheduled to come out in the spring and it will be one of the questions for him.
As for removing fish, a friend at work is a Scout leader. I asked him if his troop might want to help out with that. A couple dozen young boys with fishing poles could put a good dent in the LMB over a weekend camping camping trip in the spring. BG will be catch and release. For now I will start the log.
Bocomo, the link to your pond thread has given me a good framework to follow myself.
Thanks everyone.