EPA Redefines “Waters of the United States”

Posted on 6/8/2015 by Roger Marks

On May 27, US EPA in cooperation with the US Army Corps of Engineers (USACE) announced a Final Rule to restructure the definition of “Waters of the United States.” The definition, which sets the standard for which bodies of water EPA is authorized to regulate under its Clean Water Act, has been a point of confusion and contention for environmental regulators and industry groups for decades.

The new rule will affect industry compliance with all Clean Water Act programs, most notably:
  • Oil Discharge Notifications (40 CFR 110);
  • Spill Prevention, Control, and Countermeasure Plans (40 CFR 112);
  • NPDES Permitting and Stormwater Discharge Permits (40 CFR 122);
  • The “per-industry standards” (40 CFR 405-471); and
  • Dredge and Fill Permitting (33 CFR 323).
How the Final Rule Affects CWA Compliance

The Final Rule will affect enforcement of the Clean Water Act in a number of major ways.

First, it puts certain bodies of water under the scope of EPA water regulations “by rule.” These jurisdictional waters are under EPA’s authority in all instances. They are:
  • Traditional navigable waters (per the 1899 Rivers and Harbors Act);
  • Interstate waters, including interstate wetlands;
  • Territorial Seas;
  • Impoundments of Jurisdictional Waters;
  • Tributaries to traditional navigable waters, interstate waters, and the territorial sea; and
  • Surface waters adjacent to the above waters, including adjacent wetlands.

What Does EPA Mean by “Tributary”?

The final rule gives a more precise definition of tributaries as “waters that are characterized by the presence of physical indicators of flow—bed and banks and ordinary high water mark—and contribute flow directly or indirectly to a traditional navigable water, interstate water, or territorial seas.”

EPA contends that these indicators illustrate that there is enough volume, frequency, and flow of water to constitute a “significant nexus” between the tributary and a jurisdictional water, therefore making the tributary subject to Clean Water Act rules.
EPA oil discharge in 2015 waters of the US

What Is a “Significant Nexus”?

The phrase “significant nexus” has itself been a point of confusion for industry and regulators. The term was coined and used in US Supreme Court decisions regarding major challenges to EPA’s water authority. The Supreme Court used this phrase to mean that, to regulate a body of water not already covered by the Clean Water Act, EPA must show that the body of water could “affect the chemical, physical, or biological integrity of a jurisdictional water.”

There are five types of waters EPA has determined will be subject to a case-by-case analysis to determine if they meet the “significant nexus” threshold:
  • Prairie potholes;
  • Carolina and Delmarva bays;
  • Pocosins;
  • Western vernal pools in California; and
  • Texas prairie wetlands.
Also included in the Final Rule are standards for evaluating other bodies of water on a case-by-case basis, namely those within the 100-year floodplain of a jurisdictional water and those within 4,000 feet of the high tide line or ordinary high water mark of jurisdictional water.

Old and New Exclusions

The new Final Rule retains all the exclusions from the definition of “Waters of the US” and adds a few more that reflect longstanding Agency practice. EPA added exclusions for certain ditches, groundwater and erosional features, stormwater control or treatment conveyances, and cooling ponds created in dry land.

The Final Rule goes into effect 60 days after its publication in the Federal Register, during which time it will likely face continued challenges.

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Tags: Act, Clean, EPA, new rules, Water, WOTUS

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