On March 25, 2014, the Environmental Protection Agency (“EPA”) and the Army Corps of Engineers (“Corps”) jointly released a proposed rule purporting to clarify the scope of the “waters of the United States” protected under the Clean Water Act. The agencies claim that, as a result of the Supreme Court’s decision in Rapanos v. United States, 547 U.S. 715 (2006), the scope of regulatory jurisdiction in the proposed rule is narrower than under the existing regulations. It appears, however, that the proposed rule actually expands the scope of the waters regulated by the Act.

Rapanos considered whether wetlands, located near ditches or man-made drains that emptied into traditional navigable waters, fell within the scope of the Clean Water Act. A four-justice plurality interpreted the term “waters of the United States” as covering those “relatively permanent, standing or continuously flowing bodies of water,” Rapanos, 547 at 739, that are connected to traditional navigable waters, and wetlands with a “continuous surface connection” to such relatively permanent water bodies, id. at 742. In contrast, in a concurring opinion, Justice Kennedy concluded that “waters of the United States” includes wetlands with a “significant nexus” to traditional navigable waters. Id. at 779. He further stated that wetlands possess the requisite nexus if they “either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity” of traditional navigable waters. Id. at 780.

EPA and the Corps have imported the “significant nexus” standard from Justice Kennedy’s concurring opinion into the proposed rule, applying it not only to adjacent wetlands (the subject of Rapanos), but also to other categories of water bodies, such as tributaries of traditional navigable waters or interstate waters, and to “other waters” (that is, waters not fitting in another category). For example, the agencies represent that all tributary streams are physically and chemically connected to downstream traditional navigable waters, interstate waters, and the territorial seas via channels and associated alluvial deposits. Based on this assertion, the agencies propose that all waters that meet the new regulatory definition of “tributary” are “waters of the United States” by rule, without the need for a case-specific analysis. The agencies propose to define tributaries in reference to physical characteristics (the presence of a bed and banks and an ordinary high water mark) and contribution of flow to traditional navigable waters, interstate waters, territorial seas, and impoundments. The proposal specifies that a tributary “can be a natural, man-altered, or man-made water” and includes waters “such as rivers, streams, lakes, ponds, impoundments, canals, and ditches” not otherwise excluded. Moreover, contrary to the plurality opinion in Rapanos, the proposal provides that the flow “may be ephemeral, intermittent or perennial.”

Based on the “significant nexus” standard, the proposed rule also defines “waters of the United States” to include all waters – not just wetlands – adjacent to a traditional navigable water, interstate water, the territorial seas, impoundment or tributary. The proposed rule defines “adjacent” as bordering, contiguous, or “neighboring,” and then expansively defines “neighboring” as including waters located within the “riparian area” or “floodplain” of traditional navigable waters, interstate waters, territorial seas, covered impoundments, or covered tributaries, or waters with a shallow subsurface hydrological connection to such a jurisdictional water.

Finally, based on Justice Kennedy’s “significant nexus” standard, the proposed rule modifies the definition of “other waters” (that is, those waters not fitting in another category under “waters of the United States”). In the current regulation at 40 C.F.R. § 122.2, “other waters” are defined based on whether they could affect interstate or foreign commerce. The proposed rule deletes this language. Instead, it states that “other waters” are “waters of the United States” on a case-specific basis, where those waters alone, or in combination with other similarly situated waters located in the same region, have a “significant nexus” to – that is, significantly impact the chemical, physical, or biological integrity of – a traditional navigable water, interstate water, or the territorial seas.

Thus, in some aspects, the proposed rule expands the scope of waters protected under the Clean Water Act, and industry may wish to comment on the rule. Comments will be accepted for 90 days after the proposed rule is published in the Federal Register. EPA has submitted the proposed rule for publication in the Federal Register, but it has not been published yet. An unofficial version of the proposed rule is available here.