Via Barry Griffith, Owensboro, Ky., has a webcam pointed at the Ohio River. You can see it here.
If anyone else knows of a webcam pointed at the Ohio or one of its major tributaries, please let me know. I'll probably put links to them in the left-hand rail. And please, let it be a major tributary. The Kanawha River at downtown Charleston is one thing. Kinnickinnick Creek in Ross County, Ohio, is another.