There are a few people who dive in the TN river in the Huntsville/Decatur/Florence area, but they are a "dedicated" few.
SDI in Florence used to do "Tuesday or wednesday night dives" below Wilson Dam in the Florence area. I think their trips were free if you wanted to go. However, their Florence store is going out of business, so I don't know if they are going to do it anymore. The bottom below Wilson Damn is supposed to be hard/rockier and thus provide better water vis.
It appears the web page for it has been deleted.
http://www.sdiscuba.com/tue_night_dives.htm
Anyway, there is also a group of divers from SDI that go out and dive
in Huntsville in the river near the Whitesburg bridge. Mostly looking
for weapons and guns that have been thrown into the river. (I think
that if they can't be linked to a crime, the police will let them keep them).
But... they are diving right in the middle of the boat channel and boaters
here have no clue on any "rules" and don't expect them to respect a dive
flag.
As for Lucys Branch (aka Bay Hill Marina), that place has turned into
"Redneck Riveria". Watch for boat traffic.
I've also had this page bookmarked for a while
Diving The Tennessee River
http://home.hiwaay.net/~mdsmith/tenndive.htm
Also, as Matt reference, the Madison Rock quarry is there.
There is also another quarry in Moultan, but it's operated by
a small yet to open dive shop so I don't know its hours.
Also Bluewater in Pelham, Diveland in Glenco, and Marthas
in Tennesee are options.
Hope that helps some.
-Mike
