I have an old pond thats still in the family, its about 50 years old or so. Level is down about 6 feet, infested with duckweed. When I fished there as a kid, the fish were huge. Now I don't think there are any in it. Trees are growing in the dam, assuming thats whats causing the drainage. I shoved a stick in the bottom and it was black muck when I brought it back up. I want to bring it back to life now that I'm back living here. Should it be drained, dredged, what? Thanks for any assistance.