OP and others, if you have access to ft Belvoir there's a bridge over Dogue Creek just inside Walker Gate on the Mt Vernon side where I've gotten slab crappies over the years. I remember last spring I fished it and some guy was just crushing them using an odd rig dead drifting a weighted grub jig under a bobber. I was having no joy with my fly rod and was getting some funny looks until I finally found my Metamucil that day--a few feet of sink tip and a hideous mistake of a fly I must've tied while drunk that looked like a miniature Clouser wrapped in tinsel and chenille (schnauser?). That did the trick.
That creek is lousy with snakeheads too. I've not caught one but it is popular with bow fishers.