Proposed rule to revise the definition of “Waters of the United States”

On December 11, 2018, the Environmental Protection Agency and the Department of the Army Corps of Engineers (hereinafter, “the Agencies”) released a “Revised Definition of Waters of the United States” a revision of the 2015 Clean Water Rule (hereinafter, 2015 Rule) defining the scope of waters federally regulated under the Clean Water Act (CWA). The CWA describes its jurisdictional scope as “navigable waters,” defined in section 502(7) of the statute as “Waters of the United States” (WOTUS). The Act does not, however, clearly define which rivers, streams, and wetlands are WOTUS. A prepublication version of the proposed rule is available on the EPA website.

The 2018 proposed rule that redefines WOTUS identifies six categories of waters as jurisdictional by rule: (1) traditional navigable waters (TNW), (2) tributaries, (3) ditches, (4) lakes and ponds, (5) impoundments, and, (6) adjacent wetlands. The proposed rule does eliminate one entire category from the 2015 Rule, interstate waters, because it had no connection to navigable waters. While slightly re-configured and with new explanations, these are the same basic categories discussed in previous efforts to establish a WOTUS definition.

The 2018 proposed rule also identifies 11 categories of waters that are not WOTUS and, for the first time, the Agencies propose to add a definition of “upland” in the WOTUS definition. Several features are excluded when they occur in “uplands” and if an area is an “upland” it cannot be classified as a “wetland.” The proposal defines upland as “any land area that under normal circumstances does not satisfy all three wetland delineation criteria (i.e., hydrology, hydrophytic vegetation, hydric soils)” and “does not lie below the ordinary high-water mark (OHM) or the high tide line” of a WOTUS. This presumably would put some sideboards on how the Agencies delineate wetlands. However, the Agencies fail to define “normal circumstances” in the proposed rule.

Overall, the proposed rule would significantly limit the expanded federal authority over WOTUS as was defined in the 2015 Rule. The proposed changes to the 2015 Rule are particularly important for forest management activities involving ephemeral stream beds and wetlands and construction of ditches for minor drainage around mill sites and forest roads.

The proposed rule limits the meaning of “navigable waters” to tributaries and wetlands that have a continuous physical connection, during some part of a typical year, to TNW or the territorial seas. The Agencies consider the proposed definition of “tributary” to be more consistent with the Supreme Court’s interpretation of the Agencies’ authority than in the 2015 Rule. Under the proposed rule, only wetlands are within the “adjacent” WOTUS category. To be adjacent, they must “abut” a TNW or jurisdictional tributaries, ditches, lakes and ponds, and impoundments or have a “direct hydrological surface connection.” The Agencies state this interpretation more accurately reflects the Supreme Court’s longstanding views on the scope of jurisdictional wetlands.

The Agencies state that the proposed definitions of tributary and adjacent wetlands eliminates the need for a case-specific significant nexus test that was required for many features after Justice Kennedy’s concurring opinion in Rapanos and according to the Agencies’ Rapanos Guidance. The Agencies also state that the categorical treatment of all tributaries and adjacent wetlands, as defined by the proposed rule, “will provide clarity to the regulated public regarding the jurisdictional status of such features and ease the administrative burden the Agencies face in conducting a case-specific significant nexus analysis to complete many jurisdictional determinations under previous regulations and guidance.”

NCASI will submit comments when the final rule is published. Contact Dr. Erik Schilling ( for more information.