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January 29, 2020  |  Written by Ellen M. Simmons

Waters of the United States Redefined: EPA and Army Corps of Engineers Announce Navigable Waters Protection Rule

On Thursday, January 23, 2020, the Environmental Protection Agency (EPA) and the Department of the Army, Corps of Engineers (collectively, “Agencies”) announced the Navigable Waters Protection Rule (Final Rule), providing a new definition of “waters of the United States” for use by the Agencies to determine whether a body of water is subject to the protections of the federal Clean Water Act.  The Agencies subsequently released a pre-publication version of the Final Rule, which will become effective 60 days after publication in the Federal Register.

The Final Rule purports to remedy certain failings identified in the rule promulgated by the Obama Administration in 2015 (2015 Rule).  Specifically, it limits the scope of the Agencies’ authority under the Clean Water Act with regard to the application of United States Supreme Court jurisprudence, accords greater weight to the policy of Congress expressed in Clean Water Act section 101(b), limits encroachment of federal jurisdiction over traditional state land use authority, and eliminates the 2015 Rule’s controversial distance-based limits.

The New Definition of “Waters of the United States”

The Navigable Waters Protection Rule enumerates four categories of waters that qualify as waters of the United States (jurisdictional waters):

  1. Territorial seas, and waters which historically have been, currently are, or potentially will be used in interstate or foreign commerce, including waters subject to the ebb and flow of the tide.
  2. Tributaries of waters of the United States.
  3. Lakes and ponds that are, or contribute flow to, a traditional navigable water in a typical year, or are inundated by flooding from a jurisdictional water in a typical year, and impoundments of jurisdictional waters.
  4. Wetlands adjacent to jurisdictional waters.

Further, the Final Rule significantly amends the definition of “adjacent” as limited to those wetlands that either (i) abut one of the first three categories of waters, (ii) are inundated by flooding from one of the first three categories of waters in a typical year, or (iii) are physically separated from one of the first three categories of waters only by an artificial structure, given that a hydrologic surface connection remains in a typical year.

This amendment to the definition of “adjacent” is a substantial change from the 2015 Rule, which encompassed all wetlands, ponds, lakes, oxbows, impoundments, and similar waters located (i) within 100 feet of the ordinary high water mark of a jurisdictional water, (ii) within the 100 year flood plain of a jurisdictional water, (iii) within 1500 feet of the high tide line of a jurisdictional water, or (iv) within 1500 feet of the ordinary high water mark of the Great Lakes.

The Final Rule also eliminates the case-by-case approach used by the 2015 Rule to determine whether certain types of water bodies, such as California’s vernal pools, are jurisdictional.  Conversely, the Agencies provide the following list of twelve specific categories of waters that are not waters of the United States:

    • Waters not identified as one of the four categories of jurisdictional waters
    • Groundwater
    • Ephemeral features, e.g., streams
    • Diffuse stormwater runoff and directional sheet flow over upland
    • Ditches not covered by category (1) or (2), and portions of ditches in category (4) waters that do not meet the definition of “adjacent”
    • Prior converted cropland
    • Artificially irrigated areas that would revert to upland should irrigation cease
    • Artificial lakes and ponds, so long as not impoundments of jurisdictional waters pursuant to 33 C.F.R. § 328.3(c)(6)
    • Water-filled depressions constructed or excavated in upland or non-jurisdictional waters incidental to mining or construction activities, and pits excavated in upland or non-jurisdictional waters to obtain fill, sand, or gravel
    • Stormwater control features constructed or excavated in upland or in non-jurisdictional waters
    • Groundwater recharge, water reuse, and wastewater recycling structures
    • Waste treatment systems

Practical Impact

The Navigable Waters Protection Rule’s most significant changes are arguably the express exclusion of ephemeral streams, groundwater, and wetlands that are not directly adjacent to a jurisdictional water.  However, given that States retain the authority to regulate non-jurisdictional waters, the impact of the rulemaking will vary widely by jurisdiction.


In California, the State Water Resources Control Board administers a statewide program to permit discharges of dredged or fill material to waters of the state.  Waters of the state are defined to include “any surface water or groundwater, including saline waters, within the boundaries of the state.”  This includes but is not limited to all waters of the United States.  Under this program, all waters of the state will continue to be subject to existing discharge requirements.


Like many states, Colorado does not have an independent program to permit discharges of fill to waters of the state.  As discussed in the State of Colorado’s comment letter regarding the new “waters of the United States” rulemaking, Colorado has historically relied on the Clean Water Act section 404 permitting program.  While state officials anticipate a several year process to promulgate regulations creating a state-specific permitting program, projects will be subject to the new federal rule in the interim.

For further information on this topic, please contact Ellen Simmons at for California-specific inquiries, or Leila Behnampour at for Colorado-specific inquiries.

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