How does a law regulating river transports look like in the U.S.?

Two recent (Fall 1998) NY Times articles talked about nuclear "byproducts" (waste):

1.2 billion pounds of both chemically toxic and radioactive (basically worse than anything Saddam might come up with) uranium hexafluoride stored in 12 by 4 feet sealed cylinders slowly rusting (but they will have to be kept for a few thousands years, wouldn't they - and ooops, just 30 years passed and some of them already leak...) in:

Paducah, KY (the leaks were featured on CNN in August 1999)
Piketon, OH
Oak Ridge, TN

The first article notes that they might not be highway worthy anymore. But I don't believe anybody would transport such a huge payload by truck anyway. So, I looked at the map and YES the storage places are very conveniently located:

• Piketon, OH is a few miles from Portsmouth - a port on the river Ohio
• Oak Ridge, TN is even closer to Knoxville - a port on the river Tennessee and...
• Tennessee flows into Ohio guess where - at Paducah, KY
• not far from Paducah, KY - Ohio merges into Mississipi, which runs all the way to the Gulf

...is this a possible escape route for the US nuclear waste?

The second article suffered an op-ed reaction piece in the NY Post. The case of a Utah tribe, that Times reported was preparing to make land available for the storage of high-level nuclear waste, was labeled as a potentially lucrative undertaking that "Indians" perceive to be in their own best interest.