Also on another note as best as I can tell the falls sit in nearly 70' of water and over 150' on the bottom on past the falls so they are mostly diveable. But I imagine the water would be pretty cold.
My map contains 76 "GPS Locations" containing 29 "ruins" (including 1 church ruins). 6 bridges, several culverts, humps, and a few submerged ponds. But you have to remember the lake was complleted in Sept 1961. The first Satellite Positioning system was used in 1960 by the U.S. Navy. Point being without knowing when or where the coordinates were obtained, they are only slightly reliable.
When we attempted to dive the church ruins as we were a "short" distance form the GPS coordinate listed for the church, my sonar indicated a jagged rise of about 10 feet off the bottom then a rapid drop back to normal depth. I'm not sure what posessed me to ignore this at the time but guess thats just me. We will be back to Smith in a few weeks and i'm tryin to find a decent sonar to mount on the 24 foot pontoon we bought to dive off of. The unit on my other boat was about $300, can't justify that much on this pontoon since that would be nearly 1/2 the price of the boat.
I have heard also on the smith lake forums, that there was equipment left near the dam as the lake filled faster than expected. But im not sure how legitimate this is because of the accuracy of the engineers building the lake. They predicted and marked to within 6 inches where the water would stop when the lake was full.