What are Waters of the US?

Current Definition of Waters of the US

Since the passing of the Clean Water Act, the definition of the term “waters of the US” has been amended several times. The current definition of “waters of the US” is:

  1. Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in paragraphs (a) through (f) of this definition.
  2. The territorial sea; and
  3. Tributaries of waters identified in paragraphs (a) through (d) of this definition;
  4. All impoundments of waters otherwise defined as waters of the United States under this definition;
  5. All other waters such as interstate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce including any such waters:
    1. Which are or could be used by interstate or foreign travelers for recreational or other purposes;
    2. From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or
    3. Which are used or could be used for industrial purposes by industries in interstate commerce;
  6. All interstate waters, including interstate “wetlands”;
  7. 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;
  8. Waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of CWA are not waters of the United States.

40 CFR 122.2

Clarification to Definition of Waters of the US

Additionally, two Supreme Court cases (Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (SWANCC)(2001) and Rapanos v. United States (2006)) further interpret this definition as it applies to isolated waters of the US. These ruling led to increased confusion and complexity in interpretation of “waters of the US” for enforcement of the Clean Water Act.

Proposed Changes to the Definition of Waters of the US

In April 2014, changes to the definition of “waters of the US” were proposed by the U.S. Environmental Protection Agency (USEPA) and  the US Army Corps of Engineers (USACE).  The proposed “Clean Water Rule” was designed to clarify exactly what waters are and what waters are not jurisdictional under the Clean Water Act.

Finalized Clean Water Rule

On May 26, 2015,  after more than 400 public stakeholder meetings across the US and review of one million public comments and over 1,200 peer-reviewed, published scientific studies supporting the role of small streams and wetlands in downstream water body health, the USEPA and USACE finalized the proposed Clean Water Rule.  The new Clean Water Rule was published in the Federal Register on June 29, 2015 (Federal Register Vol. 80, No. 124) and will take effect August 28, 2015.

In recognition of the regional significance of Texas coastal prairie wetlands, Texas prairie potholes (freshwater depressional wetlands), and marsh wetlands that occur on Lissie and Beaumont Geological Formations and the Ingleside Sands on downstream water health, the Final Clean Water Rule calls for consideration of  function in combination with similar, seemingly isolated waters in determining significant nexus and jurisdiction as waters of the US:

[This] specific [type] of [water] in [this] specific [region] should be subject to a significant nexus analysis and [be] considered similarly situated by rule because they function alike and are sufficiently close to function together in affecting downstream waters . . . . [S]uch waters should be analyzed ‘in combination’ (as a group, rather than individually) in the watershed that drains to the nearest traditional navigable water, interstate water, or the territorial seas when making a case-specific analysis of whether these waters have a significant nexus to traditional navigable waters, interstate waters, or territorial seas. (22-23)

These waters are not jurisdictional as a class under the rule, but in cases where they are otherwise non-jurisdictional in and of themselves, should also be considered for jurisdiction in combination with similar waters in the watershed that also drain to a traditional navigable water, interstate water, or territorial sea.

Significant nexus means that a water, including wetlands, either alone or in combination with other similarly situated waters in the region (watershed that drains to), significantly affects the chemical, physical, or biological integrity of traditionally navigable waters, interstate waters, and territorial seas.  This affect can be in regard to sediment trapping, nutrient recycling, pollutant trapping and filtering, flood water retention, contribution to flow, export of organic mater, export of food resources, and provision of life cycle dependent aquatic habitat for species.

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