Report: EPA Proposal to Expand Clean Water Protection is Scientifically Sound

by Emily Atkin, September 23, 2014

Photo of wetlands
CREDIT: Shutterstock

A controversial proposal to expand the Environmental Protection Agency’s authority over United States waters is based on scientifically sound evidence that pollution in streams and wetlands can have a big impact on larger, downstream bodies of water, according to a draft report released by the EPA’s independent Science Advisory Board (SAB) last week.

The Science Advisory Board, a group of independent scientists chosen by the EPA to review agency reports and regulations, largely signed off on a proposed rule that would give Clean Water Act protection to about 20 million acres of wetland and two million miles of streams. Under current regulations, it’s not totally clear if these bodies of water are covered under the Clean Water Act, meaning it’s also not clear whether the EPA can pursue legal action against potential polluters.

Many agricultural groups, rural groups, and Republicans oppose the proposed rule change, calling it a case of “EPA overreach” that will put burdensome regulations on anyone with a small body of water in their backyard. But the EPA contends that it needs to regulate pollution to small sources like streams, tributaries, and wetlands because that pollution can affect downstream waters that people use for drinking water supply.

The Science Advisory Board’s report, led by University of South Florida Civil and Environmental Engineering professor James Mihelcic, said there is truth to that concern. “The available science supports the conclusion that the types of water bodies identified as waters of the United States in the proposed rule exert strong influence on the physical, biological, and chemical integrity of downstream waters,” the report said.

The report did make a few recommendations, all of which included adding more bodies of water to the EPA’s jurisdiction. For example, the report said the EPA’s decision to exclude groundwater from Clean Water Act protection does “not have strong scientific justification.”

“The available science … shows that groundwater connections, particularly via shallow flow paths in unconfined aquifers, are critical in supporting the hydrology and biogeochemical functions of wetlands and other waters,” the report reads. “Groundwater also connects waters and wetlands that have no visible surface connections.”

The Clean Water Act regulates all “navigable waters” of the United States. But under current regulations, figuring out which waters of the United States are actually “navigable” is “confusing and complex,” according to EPA. That’s because of two Supreme Court decisions in 2001 and 2006, which essentially made it so there’s lots of room for courts to interpret what “navigable” really means when considering wetlands, tributaries, ditches, and streams.

Because there’s so much room for courts to interpret what waters are regulated under the Clean Water Act, it means that lawsuits against potential polluters can take lots of time and money to argue. A good example of this is the ongoing court case against ExxonMobil, which claims the company violated the Clean Water Act when its Pegasus Pipeline ruptured in March 2013, spilling approximately 210,000 gallons of Canadian tar sands crude oil into the small community of Mayflower. Specifically, the devastating spill saw crude seeped into the cove of Lake Conway, an unnamed creek, and wetlands surrounding the spill site.

ExxonMobil’s main argument against this lawsuit is that the Clean Water Act does not cover coves, creeks, or wetlands. It uses the “navigable waters” definition to make its claim: The cove of Lake Conway, the unnamed creek, and the wetlands affected by the spill are not “navigable” by ships, ExxonMobil says, and therefore are not subject to the law. The federal judge overseeing the lawsuit seems to have rejected that argument for now, but the company can still hone in on the argument as the case progresses, or make it again on appeal.