As part of an effort to streamline implementation of the Clean Water Act (CWA), US EPA and the Army Corps of Engineers (ACOE) released a proposed rule that will establish defined categories of waters that qualify as “waters of the United States” under the CWA and will be subject to its jurisdiction. The proposed rule is a direct response to the US Supreme Court’s decisions in Solid Waste Agency of Northern Cook Cty. v. Army Corps of Engineers, 531 U.S. 159 (2001) and Rapanos v. United States, 547 U.S. 715 (2006). Newly protected categories include wetlands and seasonal streams that are upstream from navigable waters, substantially expanding the current scope of CWA jurisdiction. The Agencies believes that these resources share a significant nexus with downstream waters and that protecting them is essential to preserve water quality nationwide.

After conducting a survey of the scientific literature and available studies on the connection between bodies of water that share a hydrological connection, the Agencies argue that they are in a position to state that the following classes are “waters of the United States:”

  • All waters which are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide;
  • All interstate waters, including interstate wetlands;
  • The territorial seas;
  • All impoundments of a traditional navigable water, interstate water, the territorial seas or a tributary;
  • All tributaries of a traditional navigable water, interstate water, the territorial seas or impoundment;
  • All waters, including wetlands, adjacent to a traditional navigable water, interstate water,  the territorial seas, impoundment or tributary; and
  • On a case-specific basis, other waters, including wetlands, provided that those waters alone, or in combination with other similarly situated waters, including wetlands, located in the same region, have a significant nexus to a traditional navigable water, interstate water or the territorial seas.

A Blanket Significant Nexus Determination

In order to determine that these categories of waters meet Justice Kennedy’s “significant nexus” test,  US EPA’s Office of Research and Development conducted a “peer-reviewed synthesis of published peer-reviewed scientific literature discussing the connectivity and effects of streams and wetlands on downstream waters” over a period of months. The “peer-reviewed scientific literature” discusses the connectivity of wetlands, adjacent open waters, and tributaries, as well as the effect of that connectivity on downstream waters. Under the proposed rule, no additional analysis is required to determine that there is a significant nexus between these categories and navigable waters.

The Agencies note that the reviewed literature does not use the term “significant nexus”  to refer to the connection between different water bodies. The Agencies contend that whether there is a significant nexus depends upon the application of science to the framework established by SWANCC and Rapanos, that application—according the Agencies—is squarely within their purview.

Next Step: Public Comment Period

A 90-day public comment period begins with the imminent publication of the proposed rule in the Federal Register. The Agencies are seeking comments on the proposed rule and the best way to determine which “other waters” qualify for regulation under the CWA.  The proposed rule does not change the exclusions for waste treatment systems, or prior converted cropland, and does not affect the regulatory status of water transfers. Existing agricultural exemptions will remain in place. The proposed rule relies on general scientific evidence of connectivity between streams and wetlands with downstream waters to establish a very broad jurisdictional delineation–in essence, a  jurisdictional delineation analysis for the entire nation. The public comment period promises to be a lively one.