Great advice above.

Over the next year you will want to decide on what kind of a fishery you want. Sounds like the kid had a good time already. Its always nice when kids catch stuff instead of being bored when going after a "big one". And by the sounds of it, you may have a big one in there for you to go after. Fish it for the next year and see what you got.

I have to wonder if that spillway has eroded down to a level below the overflow pipe. I would keep an eye on that.