soonerwink has it right. . . shallow and silty. My friends and I thought it would be good for catfishing, but it isn't. Heavy boat traffic and shallow silty areas seem to keep it stirred up every time we tried it. A strange twist of visibility, we found our best dive off the north side of an island far from the dam and near the bridge across the lake. Right where the swimmers were swinging on a rope over the water. But, while it was better viz, it's not worth going back for. In the rocky areas we could see a little bit, but when you near the bottom it turned bad.
OOlogah is worse. . . went there for a body search, The water was very shallow, no visibility and deep soft mud, diving was canceled and the body floated a couple of days later.