The Environmental Protection Agency and the Army Corps of Engineers just announced a new proposed rule that will redefine "waters of the United States" (WOTUS) under the Clean Water Act (CWA). The proposed definition includes major changes to the one set by the 2020 Navigable Waters Protection Rule (NWPR), which two federal courts struck down over the summer. The changes, which were published in the Federal Register Dec. 7, could signal a return to the long-standing pre-2015 WOTUS interpretation, which has been in effect since September. Comments on the new proposed rule are due Feb. 7, 2022.

How does the NWPR define WOTUS?

The NWPR narrowed the preceding WOTUS definition in June 2020. The NWPR restricted the agencies' CWA oversight to traditional navigable bodies of water, such as interstate rivers and streams, as well as other "relatively permanent" bodies of water, such as lakes, ponds and adjacent wetlands, with direct hydrologic surface connections to traditional navigable waters.  

How does the proposed rule redefine WOTUS?

Under the proposed rule, bodies of water other than traditional navigable waters may be subject to the agencies' jurisdiction under the Clean Water Act if they are either "relatively permanent" or if they possess a "significant nexus" to traditional navigable waters. The "relatively permanent" standard maintains much of the NWPR's WOTUS definition. But under the proposed rule, a body of water may also meet the "significant nexus" standard if it-alone or with similarly situated waters in the same region-significantly affects the "chemical, physical, or biological integrity" of traditional navigable waters.

The agencies propose interpreting WOTUS to include:

  • Traditional navigable waters, interstate waters and the territorial seas, and their adjacent wetlands
  • Most WOTUS impoundments
  • Tributaries to traditional navigable waters, interstate waters, the territorial seas and impoundments that meet either the relatively permanent standard or the significant nexus standard
  • Wetlands adjacent to impoundments and tributaries that meet either the relatively permanent standard or the significant nexus standard
  • "Other waters" that meet either the relatively permanent standard or the significant nexus standard

What other changes does the new WOTUS rule include?

The proposed rule will also re-codify important and long-standing exclusions from WOTUS for waste treatment systems, prior-converted crop lands and irrigation ditches. It will not disturb CWA permitting exemptions for normal farming, ranching and silviculture activities. But it does not maintain all of the NWPR exclusions for features such as groundwater, most ditches and ephemeral streams. Instead, these features will be subject to case-by-case determinations of jurisdiction under either the "relatively permanent" or "significant nexus" standards.

When will the new rule take effect?

The proposed rule was published in the Federal Register on Dec. 7, 2021. Comments must be submitted on or before Feb. 7, 2022. The agencies are actively asking for comments from stakeholders on some aspects of the rule, including the jurisdictional reach of its WOTUS definition, how states and tribes might fill gaps in the new rule's coverage, and the scope and implementation of its "relatively permanent" and "significant nexus" tests.

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