What's your definition of "navigable waters"?

According to this article, many of America's largest water polluters are outside of the Clean Water Act's reach due to the Supreme Court leaving out these waterways from the law.  Consequently, these polluters are claiming that the law does not apply to their businesses, and pollution rates are rising.  The Clean Water Act was supposed to regulate every polluter, thereby ending dangerous water pollution.  However, currently, as many as half of all the nation's largest pollution contributors continue to pollute because the EPA and other officials lack jurisdiction.  

A court ruling limited the Clean Water Act to applying in "navigable waters," which, for decades, included most large wetlands and streams that connected to major rivers.  But recently, waterways that are entirely in one state, creeks that sometimes run dry, and lakes unconnected to larger water systems may not be technically "navigable" and therefore are not under the Act's jurisdiction.        

“We are, in essence, shutting down our Clean Water programs in some states,” said Douglas F. Mundrick, an E.P.A. lawyer in Atlanta. “This is a huge step backward. When companies figure out the cops can’t operate, they start remembering how much cheaper it is to just dump stuff in a nearby creek.”

I think this fact is frightening as well as frustrating.  It seems like companies will do anything to do the least amount of work possible, regardless of the consequences.  Something within the law needs to be changed, clarified, or both, especially because pollution from these waterways unprotected by the law can make its way into sources of drinking water.  

The mouth of Avondale Creek in Alabama, into which a pipe maker dumped oil, lead and zinc.
A court ruling made the waterway exempt from the Clean Water Act.

View the whole article here: http://www.nytimes.com/2010/03/01/us/01water.html?_r=1