By Amena Saiyid
Aug. 21 — A ditch that is excavated in uplands and has less than perennial flow would not be subject to Clean Water Act jurisdiction under an Environmental Protection Agency proposal, an agency official told a panel of scientists.
David Evans, acting deputy director for the EPA Office of Wetlands, Oceans and Watersheds, clarified on Aug. 20 and again a day later that the purpose of the proposed waters of the U.S. rule is to not regulate every ditch, but to clarify that some ditches with perennial flows to navigable waters could fall under the jurisdiction of the Clean Water Act.
Evans said the proposed language on ditches is meant to clarify existing regulations, which do not address the subject.
He was responding to a question from David Allen, chairman of the EPA Science Advisory Board during an Aug. 20 teleconference to discuss the scientific and technical adequacy of the proposed waters of the U.S. rule, which the EPA and the U.S. Army Corps of Engineers jointly published April 21.
Allen was concerned because the majority of ditches in the Midwest that connect through intermittent flows to downstream waters would be exempt from Clean Water Act jurisdiction under the proposed rule.
The panel of scientists, who were selected by the SAB, also met Aug. 21. The panel chairwman said she would submit a summary of comments to the full board to consider at its Sept. 26 meeting.
Allen, a chemical engineering professor at the University of Texas-Austin, asked Evans to clarify the jurisdictional status of ditches that are connected to navigable waters.
Evans also clarified that ditches that are excavated through streams, irrespective of whether they are perennial, ephemeral or intermittent, would be considered tributaries, which are jurisdictional under this proposed rule. Also, ditches excavated through wetlands could be evaluated as being jurisdictional, he said.
The responses by Evans buttressed what agency officials have been saying since April at numerous panel discussions and congressional hearings and in the proposed rule itself.
“For the first time, the agencies are clarifying that all ditches that are constructed in dry lands, that drain only dry lands, and don't have perennial flow, are not ‘waters of the U.S.' This includes many roadside ditches and many ditches collecting runoff or drainage from crop fields,” the agencies' fact sheet on the proposed rule said.
Following his explanation on ditches, Evans fielded questions from other panelists about the new definitions of “significant nexus” that the agencies are proposing for the first time under the umbrella of what defines a water of the U.S.
Genevieve Ali, assistant professor in the University of Manitoba's Department of Geological Sciences, asked Evans whether the agencies would be using science or scientific criteria to establish significant nexus.
Evans told her that “significant nexus” was a legal term of art articulated by Supreme Court Justice Anthony Kennedy in Rapanos v. United States. The purpose of Kennedy's test was to identify which waters fell under the Clean Water Act jurisdiction based on whether there is a significant nexus with downstream navigable waters and wetlands.
Evans said defining “significant nexus” would require a policy determination on the part of the agencies. He clarified that the determination wouldn't be based on statistical significance tests.
“We don't have quantitative metrics or factors,” Evans said, adding that the determination would be based on a weight of evidence gleaned from science and field observations.
After Evans left the teleconference, panel members continued to debate the definition of “significant nexus” and the way that term has been used throughout the document with little clarification.
Michael Gooseff, environmental and civil engineering professor at Pennsylvania State University, suggested that the agencies provide more examples of “significant nexus” in the text.
During the Aug. 21 teleconference, Amanda Rodewald, panel chairwoman and director of conservation science at the Cornell Lab of Ornithology in Cornell University, emphasized that the summary of points raised by panel members would mention that the terms “significant nexus” and “significance” are poorly defined.
According to Rodewald, the panel agreed that the features, such as artificial ponds, that the agencies excluded from Clean Water Act jurisdiction were not backed by science, but rather were policy decisions made by the agencies.
On the subject of ditches, “there is much work that needs to be done to really identify which ones should be excluded, and which ones should be included on the basis of science,” she said, summing up the sentiment of the panelists.
Allen, who led the discussion on various types of artificial water bodies, such as certain ditches, swimming pools and artificial ornamental ponds, among others, that have typically been excluded from Clean Water Act jurisdiction. He said the agencies gave short shrift to the connectivity of ditches to navigable waters. In fact, he said there is no scientific basis for the exclusion.
Likewise, Duncan Patten, director of Montana Water Center and research professor with the Montana State University's Department of Land Resources and Environmental Science, was concerned that the EPA has not attempted to define upland, which remains an imprecise and vague term.
Kenneth Kolm, president and senior hydrogeologist at Golden, Colo.-based Hydrologic Systems Analysis LLC, questioned the status of gullies, developed as a result of grazing, that contribute perennial flows in the Western U.S.
Mark Rains, associate professor of ecohydrology at the University of South Florida, said it's worth having a discussion about ditches and gullies in terms of tributaries, which the rule is proposing to include under Clean Water Act jurisdiction.
Toward the end of the two-day webinar, Evans told the panelists that the agency would consider whether using intermittent flows would serve as a “a better dividing line” for excluding ditches from Clean Water Act jurisdiction.
The joint proposed rule would bring under federal jurisdiction all tributaries of streams, lakes, ponds and impoundments, as well as wetlands that affect the chemical, physical and biological integrity of larger, navigable downstream waters (79 Fed. Reg. 22,218).
The proposed rule also would allow the EPA and corps to seek comment on a case-by-case basis regarding whether the aggregate effect of geographically isolated wetlands and other waters that “significantly” affect the physical, biological and chemical integrity of federally protected downstream waters are jurisdictional.
To contact the reporter on this story: Amena H. Saiyid in Washington at email@example.com
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