Ft. Loudoun Crappie Beds

As for where to put them, I would suggest reading in the "Crappie Cover, Lake Structure and Pond Management" forum. There are lots of threads on that topic. The general consensus seems to be areas without a lot of existing cover, on or near depth changes, humps, ledges, channel edges, etc. In a line from deep to shallow is popular, with pvc structures deep and natural ones like Christmas trees shallower. There is tons of info from people much wiser than me.

As for whether you need permission, technically you need permission from either the Army Corps of Engineers, TVA, or TWRA, whomever operates the lake. You have to submit an application stating where it will be, and what type of structure it is (materials, etc.) Their main concern is safety. They don't want things placed in the lake that could become boating hazards because they are too shallow when the water drops, etc. TWRA's website has the information to apply for a permit. They also state that if it becomes a hazard or in disrepair, you will be responsible for removing it.

A fourth question would be "Does anyone actually go through the rigamarole to get a permit?" The answer to that is almost certainly no. Just use common sense, be safe for yourself and others, and don't use materials that would be bad for the environment and you should be fine.

Edit: I didn't see the part of your question about ANY lakes at first. If it was one of TWRA's pay lakes or something where they are more closely monitored, I wouldn't even bother. The other "normal" lakes, I guarantee you there are thousands of Christmas trees and who knows what else already there that TWRA doesn't know anything about. I always take mine right before dark, or on a crappy weather day when I know no one will see me drop it. (So hopefully they won't be fishing on it when I come back in the spring. [emoji6]) I guess that keeps TWRA from seeing me do it, too.