Clarification is the moving force behind the rule, said Stoner.

 “We have an opportunity to shore up the system of protections Congress put in place in 1972,” she said to the more than 2,200 participants in the webcast. “We want to define what is and what is not protected and clarify the definition of (Waters of the United Sates).

“No new types of water are protected. If something was not covered by the Clean Water Act before, it’s not covered now. The primary purpose of the rule change is to clarify what is covered.”

Some streams that are “seasonal” in nature, only flowing during certain parts of the year or after rainfall, are covered, if they connect with other navigable streams. “Some 60 percent of streams are seasonal,” Stoner said, “but they have a huge impact on downstream waters. We can’t protect large bodies of water without protecting smaller waters that feed them.”

She said streams supply water to 117 million Americans, one out of every three.

The old definitions of Waters of the United States, covered by the Clean Water Act, “were confusing and lacked clarity,” Stoner said. That lack of understanding prevented the EPA from taking action against some polluters that were causing significant damage to bodies of water. “The issues were not pursued because the (charges) were too complex to prove.”

She noted Edwards Creek near Talco, Texas, as one example of a stream polluted by crude oil discharge, but the perpetrator was never charged because of the complexity of proving the stream was covered.  Cases concerning Georgia’s Blackshear Lake and Arizona’s San Pedro River also were not pursued because of the complexity of proving the water was protected under the Clean Water Act.