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April 22, 2014  |  Written by Somach Simmons & Dunn

Proposed Rule Released: Defining “Waters of the United States” Under the Clean Water Act

On March 25, 2014, the United States Environmental Protection Agency (EPA) and the United States Army Corps of Engineers (collectively, Agencies) jointly issued their long-awaited proposed rule to, in their words, “clarify” the definition of “waters of the United States” (the Proposed Rule) under the Clean Water Act (CWA).  The revised definition would apply to all CWA programs.  The Agencies propose for the first time to define various terms, including “tributary” and “significant nexus.”  The Proposed Rule was published in the Federal Register on April 21, 2014, and comments are due on or before July 21, 2014.

The Proposed Rule follows the EPA’s release of its draft science report, Connectivity of Streams and Wetlands to Downstream Waters:  A Review of and Synthesis of Scientific Evidence (Report), for comment on September 24, 2013.  A summary of the Report can be found here.  The Agencies rely on the Report as scientific support for the Proposed Rule.

“Waters of the United States” Defined

The Agencies claim that the Proposed Rule will bring greater certainty and fewer case-by-case decisions on the jurisdiction of waters and wetlands following the Supreme Court’s decisions inRapanos v. United States, 547 U.S. 715 (2006) (Rapanos) and Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159 (2001) (SWANCC).  The Proposed Rule essentially has two tests for CWA jurisdiction:  (1) waters that qualify as “waters of the United States” by rule; and (2) “other waters” that are shown on a case-by-case basis to meet the “significant nexus” test.

Under section (a) of the Proposed Rule, the following six categories of water would be “waters of the United States” by rule, and would fall under the CWA’s jurisdiction without any additional analysis:  (1) traditional navigable waters; (2) interstate waters (including interstate wetlands); (3) the territorial seas; (4) impoundments of waters in (1) through (3); (5) all tributaries of waters in (1) through (4); and (6) waters and wetlands adjacent to waters in (1) through (5).  The “by rule” test would ensure that waters and wetlands that fit within the revised definition of “waters of the United States” would always be jurisdictional, unless specifically excluded elsewhere.

Important new definitions that compliment the Proposed Rule’s definition of “waters of the United States” include, but are not limited to, “adjacent,” “neighboring,” and “tributary”:

  1. Tributary:  The Agencies would define the term “tributary” for the first time by “the presence of a bed and banks and ordinary high water mark.”  Proposed Rule at 47.  By definition, wetlands, lakes, and ponds that contribute flow to jurisdictional waters, either directly or indirectly, would also be considered tributaries despite lacking banks and an ordinary high water mark.  A tributary would be considered jurisdictional under the CWA as long as it drains into, or is part of a network of tributaries that drain into:  (1) a traditional navigable water; (2) an interstate water; (3) the territorial seas; (4) an impoundment of waters in (1) through (3); or (5) a tributary of waters in (1) through (4).
  2. Adjacent:  The Proposed Rule would expand the meaning of the term “adjacent.”  Existing regulations cover only adjacent wetlands, whereas the Proposed Rule covers both adjacent waters and wetlands, newly defined as “adjacent waters.”  Further, while the term “adjacent” would continue to be defined as “bordering, contiguous, or neighboring,” the Proposed Rule adds a new definition for the term “neighboring.”  This revision to the term “adjacent” would ensure that “water bodies such as ponds and oxbow lakes, as well as wetlands, adjacent to jurisdictional waters are ‘waters of the United States’ by rule.”  Proposed Rule at 75.
  3. Neighboring:  “Neighboring” waters would include “waters located within the riparian area or flood plain of” waters of the United States, or “waters with a shallow subsurface hydrologic connection or confined surface hydrologic connection” to “waters of the United States.”  Proposed Rule at 75, 78.  The new definition does not require any nexus analysis and arguably expands the reach of the CWA to include entire floodplains or riparian areas.  It should be noted, however, that the Proposed Rule states, “[a]bsolutely no uplands located in ‘riparian areas’ and ‘floodplains’ can ever be ‘waters of the United States’ subject to jurisdiction of the CWA.”  Proposed Rule at 77.

If a water body does not fit within the six categories of jurisdictional waters by rule, it may nonetheless fall under the CWA’s jurisdiction under the seventh category of waters, identified as “other waters,” on a case-by-case basis.  “Other waters” fall under the CWA’s jurisdiction when the case-specific analysis demonstrates that such 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, an interstate water, or the territorial seas.  “How these ‘other waters’ are aggregated for a case-specific significant nexus analysis depends on the functions they perform and their spatial arrangement within the ‘region’ or watershed.”  Proposed Rule at 90-91.

The Agencies interpret “region” as an area “within which similarly situated waters would be aggregated as the watershed that drains to the nearest traditional navigable water, interstate water, or the territorial seas.”  Proposed Rule at 92.  The Proposed Rule further defines the scope of “significant nexus” in terms of connectivity, as waters that significantly affect the chemical, physical, or biological integrity of a traditional navigable water, an interstate water, or the territorial seas.  Proposed Rule at 31-32.

Waters and Features that are not “waters of the United States”

The Agencies state that the Proposed Rule does not change the exemptions for waste treatment systems and prior converted cropland, or other statutory exemptions from CWA permitting requirements.  Specifically, section (b) of the Proposed Rule states the following waters and features are not “waters of the United States”:

  • Waste treatment systems, including treatment ponds or lagoons, designed to meet the requirements of the Clean Water Act.
  • Prior converted cropland.  Notwithstanding the determination of an area’s status as prior converted cropland by any other federal agency, for the purposes of the Clean Water Act the final authority regarding Clean Water Act jurisdiction remains with EPA.
  • Ditches that are excavated wholly in uplands, drain only uplands, and have less than perennial flow.
  • Ditches that do not contribute flow, either directly or through another water, to a traditional navigable water, interstate water, the territorial seas or an impoundment of a jurisdictional water.
  • The following features:
    • artificially irrigated areas that would revert to upland should application of irrigation water to that area cease;
    • artificial lakes or ponds created by excavating and/or diking dry land and used exclusively for such purposes as stock watering, irrigation, settling basins, or rice growing;
    • artificial reflecting pools or swimming pools created by excavating and/or diking dry land;
    • small ornamental waters created by excavating and/or diking dry land for primarily aesthetic reasons;
    • water-filled depressions created incidental to construction activity;
    • groundwater, including groundwater drained through subsurface drainage systems; and
    • gullies and rills and non-wetland swales.

Proposed Rule at 23-34.

Although the Proposed Rule proposes to clarify and specify the exclusions to provide more certainty, actual application of the exclusions and their applicability to different industries should be considered carefully.


The Proposed Rule appears to expand the CWA’s jurisdiction to automatically include waters that previously would have required additional analysis before being designated jurisdictional.  This issue will likely be raised in several comments, as well as questions regarding the Proposed Rule’s consistency with Rapanos and SWANCC.  The regulated community should review the implications of the Proposed Rule carefully.

Further information regarding the Proposed Rule and the process for commenting on the rule can be accessed here.

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