[Federal Register Volume 88, Number 11 (Wednesday, January 18, 2023)]
[Rules and Regulations]
[Pages 3004-3144]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-28595]



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Vol. 88

Wednesday,

No. 11

January 18, 2023

Part II





Department of Defense





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Department of the Army, Corps of Engineers





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33 CFR Part 328





Environmental Protection Agency





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40 CFR Part 120





Revised Definition of ``Waters of the United States''; Final Rule

  Federal Register / Vol. 88, No. 11 / Wednesday, January 18, 2023 / 
Rules and Regulations  

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DEPARTMENT OF DEFENSE

Department of the Army, Corps of Engineers

33 CFR Part 328

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 120

[EPA-HQ-OW-2021-0602; FRL-6027.4-01-OW]
RIN 2040-AG19


Revised Definition of ``Waters of the United States''

AGENCY: Department of the Army, Corps of Engineers, Department of 
Defense; and Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) and the Department 
of the Army (``the agencies'') are finalizing a rule defining the scope 
of waters protected under the Clean Water Act. In developing this rule, 
the agencies considered the text of the relevant provisions of the 
Clean Water Act and the statute as a whole, the scientific record, 
relevant Supreme Court case law, and the agencies' experience and 
technical expertise after more than 45 years of implementing the 
longstanding pre-2015 regulations defining ``waters of the United 
States.''
    This final rule advances the objective of the Clean Water Act and 
ensures critical protections for the nation's vital water resources, 
which support public health, environmental protection, agricultural 
activity, and economic growth across the United States.

DATES: This action is effective on March 20, 2023.

ADDRESSES: The agencies have established a docket for this action under 
Docket ID No. EPA-HQ-OW-2021-0602. All documents in the docket are 
listed on the https://www.regulations.gov/ website. Although listed in 
the index, some information is not publicly available, e.g., CBI or 
other information whose disclosure is restricted by statute. Certain 
other material, such as copyrighted material, is not placed on the 
internet and will be publicly available only in hard copy form. 
Publicly available docket materials are available electronically 
through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Whitney Beck, Oceans, Wetlands and 
Communities Division, Office of Water (4504-T), Environmental 
Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460; 
telephone number: (202) 564-2281; email address: [email protected], and 
Stacey Jensen, Office of the Assistant Secretary of the Army for Civil 
Works, Department of the Army, 108 Army Pentagon, Washington, DC 20310-
0104; telephone number: (703) 459-6026; email address: 
[email protected].

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. Executive Summary
II. General Information
    A. What action are the agencies taking?
    B. What is the agencies' authority for taking this action?
    C. What are the incremental costs and benefits of this action?
III. Background
    A. Legal Background
    1. The Clean Water Act
    2. The 1986 Regulations Defining ``Waters of the United States''
    3. U.S. Supreme Court Decisions
    4. Post-Rapanos Appellate Court Decisions
    5. Post-Rapanos Implementation of the 1986 Regulations
    B. The Agencies' Post-Rapanos Rules
    1. The 2015 Clean Water Rule
    2. The 2019 Repeal Rule
    3. The 2020 Navigable Waters Protection Rule
    4. Legal Challenges to the Rules
    5. 2021 Executive Order and Review of the Navigable Waters 
Protection Rule
    C. Summary of Co-Regulator Engagement and Stakeholder Outreach
IV. Revised Definition of ``Waters of the United States''
    A. Basis for This Rule
    1. The Agencies Are Exercising the Authority Granted by Congress 
To Define ``Waters of the United States'' Under the Clean Water Act
    2. This Rule Advances the Objective of the Clean Water Act
    3. The Scope of This Rule Is Limited Consistent With the Law, 
the Science, and Agency Expertise
    4. This Rule is Both Generally Familiar and Implementable
    5. Public Comments Received and Agency Responses
    B. Alternatives to This Rule
    1. 2015 Clean Water Rule
    2. 2019 Repeal Rule
    3. 2020 NWPR
    C. This Rule
    1. Summary of This Rule
    2. Traditional Navigable Waters, the Territorial Seas, and 
Interstate Waters
    3. Impoundments
    4. Tributaries
    5. Adjacent Wetlands
    6. Waters Not Identified in Paragraphs (a)(1) Through (4)
    7. Exclusions
    8. Other Definitions
    9. Significantly Affect
    10. Guidance for Landowners on How To Know When Clean Water Act 
Permits Are Required
    D. Placement of the Definition of ``Waters of the United 
States'' in the Code of Federal Regulations
    E. Severability
    F. Jurisdictional Determinations Issued Under Previous Rules
    G. Implementation Tools
    H. Publicly Available Jurisdictional Information and Permit Data
V. Statutory and Executive Order reviews
    A. Executive Order 12866: Regulatory Planning and Review; 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    K. Congressional Review Act

I. Executive Summary

    Congress enacted the Federal Water Pollution Control Act Amendments 
of 1972, Public Law 92-500, 86 Stat. 816, as amended, 33 U.S.C. 1251 et 
seq. (Clean Water Act or Act) ``to restore and maintain the chemical, 
physical, and biological integrity of the Nation's waters.'' 33 U.S.C. 
1251(a). In doing so, Congress performed a ``total restructuring'' and 
``complete rewriting'' of the then-existing statutory framework, 
designed to ``establish an all-encompassing program of water pollution 
regulation.'' City of Milwaukee v. Illinois, 451 U.S. 304, 317-18 
(1981) (citation omitted). Congress thus intended the 1972 Act to be a 
bold step forward in providing protections for the nation's waters.
    Central to the framework and protections provided by the Clean 
Water Act is the term ``navigable waters,'' \1\ defined broadly in the 
Act as ``the waters of the United States, including the territorial 
seas.'' 33 U.S.C. 1362(7). This term is relevant to the scope of

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most Federal programs to protect water quality under the Clean Water 
Act--for example, water quality standards, permitting to address 
discharges of pollutants, including discharges of dredged or fill 
material, processes to address impaired waters, oil spill prevention, 
preparedness and response programs, and Tribal and State water quality 
certification programs--because the Clean Water Act uses the term 
``navigable waters'' in establishing such programs.
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    \1\ To avoid confusion between the term ``navigable waters'' as 
defined in the Clean Water Act and its implementing regulations, 33 
U.S.C. 1362(7); 33 CFR 328.3 (2014), and the use of the term 
``navigable waters'' to describe waters that are, have been, or 
could be used for interstate or foreign commerce, 33 CFR 328.3(a)(1) 
(2014), this preamble will refer to the latter as ``traditional 
navigable waters'' or waters that are ``navigable-in-fact.''
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    As a unanimous Supreme Court concluded decades ago, Congress 
delegated a ``breadth of federal regulatory authority'' in the Clean 
Water Act and expected the Environmental Protection Agency (EPA) and 
the Department of the Army (``the agencies'') to tackle the ``inherent 
difficulties of defining precise bounds to regulable waters.'' United 
States v. Riverside Bayview Homes, 474 U.S. 121, 134 (1985) 
(``Riverside Bayview''). The Supreme Court noted that ``[f]aced with 
such a problem of defining the bounds of its regulatory authority, an 
agency may appropriately look to the legislative history and underlying 
policies of its statutory grants of authority.'' Id. at 132. The Court 
went on to state that ``[p]rotection of aquatic ecosystems, Congress 
recognized, demanded broad federal authority to control pollution, for 
`[w]ater moves in hydrologic cycles and it is essential that discharge 
of pollutants be controlled at the source.' '' Id. at 132-33 (citations 
omitted). The Supreme Court has twice more addressed the complex issue 
of Clean Water Act jurisdiction over ``waters of the United States.'' 
Solid Waste Agency of Northern Cook County v. U.S. Army Corps of 
Engineers, 531 U.S. 159 (2001) (``SWANCC''); Rapanos v. United States, 
547 U.S. 715 (2006) (``Rapanos'').
    This rule takes up that multi-faceted challenge. In developing this 
rule, the agencies considered the text of the relevant provisions of 
the Clean Water Act and the statute as a whole, the scientific record, 
relevant Supreme Court case law, and the agencies' experience and 
technical expertise after more than 45 years of implementing the 
longstanding pre-2015 regulations defining ``waters of the United 
States.'' The agencies' experience includes more than a decade of 
implementing those regulations consistent with the Supreme Court's 
decisions in Riverside Bayview, SWANCC, and Rapanos. The agencies also 
considered the extensive public comments on the proposed rule.
    This rule establishes limits that appropriately draw the boundary 
of waters subject to Federal protection. When upstream waters 
significantly affect the integrity of waters for which the Federal 
interest is indisputable--the traditional navigable waters, the 
territorial seas, and interstate waters--this rule ensures that Clean 
Water Act programs apply to protect those paragraph (a)(1) waters by 
including such upstream waters within the scope of the ``waters of the 
United States.'' Where waters do not significantly affect the integrity 
of waters for which the Federal interest is indisputable, this rule 
leaves regulation exclusively to the Tribes and States.\2\ 
Additionally, it is important to note that the fact that a water is one 
of the ``waters of the United States'' does not mean that no activity 
can occur in that water; rather, it means that activities must comply 
with the Clean Water Act's permitting programs, and those programs 
include numerous statutory exemptions and regulatory exclusions.
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    \2\ As explained in section IV.A.3.a.ii of this preamble, the 
agencies find it appropriate to assert Federal jurisdiction over 
waters meeting the relatively permanent standard in addition to 
waters meeting the significant nexus standard because--though the 
relatively permanent standard identifies only a subset of the 
``waters of the United States''--it provides important efficiencies 
and additional clarity for regulators and the public by more readily 
identifying a subset of waters that will virtually always 
significantly affect paragraph (a)(1) waters; i.e., those waters for 
which the Federal interest is indisputable. By promulgating a rule 
interpreting the Clean Water Act to cover waters that meet the 
relatively permanent standard or the significant nexus standard, the 
agencies have appropriately construed the Act to protect those 
waters necessary to protect the integrity of traditional navigable 
waters, the territorial seas, and interstate waters, while leaving 
regulatory authority over all the waters that do not have the 
requisite connection to paragraph (a)(1) waters exclusively to the 
Tribes and States.
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    EPA and the Corps have separate regulations defining the statutory 
term ``waters of the United States,'' but their interpretations were 
substantially similar and remained largely unchanged between 1977 and 
2015. See, e.g., 42 FR 37122, 37144 (July 19, 1977); 44 FR 32854, 32901 
(June 7, 1979). This rule is founded on that familiar pre-2015 
definition that has bounded the Clean Water Act's protections for 
decades, has been codified multiple times, and has been implemented by 
every administration in the last 45 years.\3\ The pre-2015 regulations 
are commonly referred to as ``the 1986 regulations,'' and this preamble 
will refer to them as such, but the agencies note that ``the 1986 
regulations'' have largely been in place since 1977 and were also 
amended in 1993 to add an exclusion.\4\
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    \3\ The Corps' 1977 regulations (42 FR 37122, 37144 (July 19, 
1977)), though organized differently than their 1986 regulations, 
contained many of the same categories as those later regulations, 
and its definition of ``adjacent'' was identical to the definition 
promulgated in 1986. EPA's 1979 regulations (44 FR 32854, 32901 
(June 7, 1979)) were substantially similar to the Corps' 1977 
regulations and added for the first time an exclusion for waste 
treatment systems. In 1986 and 1988, the Corps and EPA, 
respectively, promulgated nearly identical definitions of ``waters 
of the United States.'' 51 FR 41206, 41217 (November 13, 1986); 53 
FR 20764, 20765 (June 6, 1988). Besides the addition of an exclusion 
for prior converted cropland in 1993 (58 FR 45008, 45031 (August 25, 
1993)), the agencies' regulations defining ``waters of the United 
States'' remained unchanged until the agencies finalized the 2015 
Clean Water Rule (80 FR 37054, 37104 (June 29, 2015)). In 2019, the 
agencies repromulgated their pre-2015 regulations (84 FR 56626, 
56667 (October 22, 2019)).
    \4\ For convenience, in this preamble the agencies will 
generally cite the Corps' longstanding regulations and will refer to 
them as ``the 1986 regulations,'' ``the pre-2015 regulations,'' or 
``the regulations in place until 2015.'' These references are 
inclusive of EPA's comparable regulations that were recodified in 
1988 and of the exclusion for prior converted cropland, which both 
agencies added in 1993.
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    Since 2015, the agencies have finalized three rules revising the 
definition of ``waters of the United States.'' See 80 FR 37054 (June 
29, 2015); 84 FR 56626 (October 22, 2019); 85 FR 22250 (April 21, 
2020). The most recent rule, the 2020 ``Navigable Waters Protection 
Rule'' (``2020 NWPR''), substantially departed from prior rules 
defining ``waters of the United States.'' On January 20, 2021, 
President Biden signed Executive Order 13990, entitled ``Executive 
Order on Protecting Public Health and the Environment and Restoring 
Science to Tackle the Climate Crisis,'' directing all executive 
departments and agencies to immediately review and, as appropriate and 
consistent with applicable law, take action to address the promulgation 
of Federal regulations and other actions that conflict with national 
policies of science-based decision making in order to improve public 
health, protect our environment, and ensure access to clean air and 
water. 86 FR 7037 (published January 25, 2021, signed January 20, 
2021). After completing a review of and reconsidering the record for 
the 2020 NWPR, on June 9, 2021, the agencies announced their intention 
to revise or replace the rule. The 2020 NWPR was subsequently vacated 
by two district courts, as discussed further below.
    In this rule, consistent with the general framework of the 1986 
regulations, the agencies interpret the term ``waters of the United 
States'' to include:
     traditional navigable waters, the territorial seas, and 
interstate waters (``paragraph (a)(1) waters'');
     impoundments of ``waters of the United States'' 
(``paragraph (a)(2) impoundments'');
     tributaries to traditional navigable waters, the 
territorial seas, interstate waters, or paragraph (a)(2)

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impoundments when the tributaries meet either the relatively permanent 
standard or the significant nexus standard (``jurisdictional 
tributaries'');
     wetlands adjacent to paragraph (a)(1) waters, wetlands 
adjacent to and with a continuous surface connection to relatively 
permanent paragraph (a)(2) impoundments, wetlands adjacent to 
tributaries that meet the relatively permanent standard, and wetlands 
adjacent to paragraph (a)(2) impoundments or jurisdictional tributaries 
when the wetlands meet the significant nexus standard (``jurisdictional 
adjacent wetlands''); and
     intrastate lakes and ponds, streams, or wetlands not 
identified in paragraphs (a)(1) through (4) that meet either the 
relatively permanent standard or the significant nexus standard 
(``paragraph (a)(5) waters'').
    The ``relatively permanent standard'' refers to the test to 
identify relatively permanent, standing or continuously flowing waters 
connected to paragraph (a)(1) waters, and waters with a continuous 
surface connection to such relatively permanent waters or to 
traditional navigable waters, the territorial seas, or interstate 
waters. The ``significant nexus standard'' refers to the test to 
identify waters that, either alone or in combination with similarly 
situated waters in the region, significantly affect the chemical, 
physical, or biological integrity of traditional navigable waters, the 
territorial seas, or interstate waters--i.e., the paragraph (a)(1) 
waters. The regulatory text defines ``significantly affect'' in order 
to increase the clarity and consistency of implementation of the 
significant nexus standard.
    With respect to ``adjacent wetlands,'' the concept of adjacency and 
the significant nexus standard create separate, additive limitations 
that work together to ensure that such wetlands are covered (i.e., 
jurisdictional under the Act) when they have the necessary relationship 
to other covered waters. The adjacency limitation focuses on the 
relationship between the wetland and the covered water to which it is 
adjacent. Consistent with the plain meaning of the term and the 
agencies' 45-year-old definition of ``adjacent,'' the rule requires 
that an ``adjacent wetland'' be ``bordering, contiguous, or 
neighboring'' to another covered water.\5\ Where a wetland is adjacent 
to a traditional navigable water, the territorial seas, or an 
interstate water, consistent with longstanding regulations and 
practice, no further inquiry is required, and the wetland is 
jurisdictional. But where a wetland is adjacent to a covered water that 
is not a traditional navigable water, the territorial seas, or an 
interstate water, such as a tributary, this rule requires an additional 
showing for that adjacent wetland to be covered: the wetland must 
satisfy either the relatively permanent standard or the significant 
nexus standard. And that inquiry, under either standard, fundamentally 
concerns the adjacent wetland's relationship to the relevant paragraph 
(a)(1) water rather than the relationship between the adjacent wetland 
and the covered water to which it is adjacent. In other words, the 
adjacent wetland must have a continuous surface connection to a 
relatively permanent, standing or continuously flowing water connected 
to a paragraph (a)(1) water or must either alone or in combination with 
similarly situated waters significantly affect the chemical, physical, 
or biological integrity of a paragraph (a)(1) water.
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    \5\ The agencies have a longstanding, specific definition of 
``adjacent,'' and section IV.C.6 of this preamble provides 
additional clarity by articulating the criteria the agencies have 
long used to interpret and implement that definition.
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    In addition, this rule codifies several exclusions from the 
definition of ``waters of the United States,'' including longstanding 
exclusions for prior converted cropland and waste treatment systems, 
and for features that were generally considered non-jurisdictional 
under the pre-2015 regulatory regime.\6\
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    \6\ The ``pre-2015 regulatory regime'' refers to the agencies' 
pre-2015 definition of ``waters of the United States,'' implemented 
consistent with relevant case law and longstanding practice, as 
informed by applicable guidance, training, and experience.
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    This rule advances the Clean Water Act's statutory objective as it 
is informed by the best available science concerning the functions 
provided by upstream tributaries, adjacent wetlands, as well as 
intrastate lakes and ponds, streams, and wetlands that do not fall 
within the other jurisdictional categories to restore and maintain the 
water quality of traditional navigable waters, the territorial seas, 
and interstate waters (i.e., the paragraph (a)(1) waters). A 
comprehensive report prepared by EPA's Office of Research and 
Development entitled Connectivity of Streams and Wetlands to Downstream 
Waters: A Review and Synthesis of the Scientific Evidence \7\ 
(hereinafter, ``Science Report'') in 2015 synthesized the peer-reviewed 
science. Since the release of the Science Report, additional published 
peer-reviewed scientific literature has strengthened and supplemented 
the report's conclusions. The Technical Support Document for the Final 
Rule: Revised Definition of ``Waters of the United States'' 
(hereinafter, ``Technical Support Document'') provides additional 
scientific and technical information about issues raised in this 
rule.8 9
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    \7\ U.S. Environmental Protection Agency, Connectivity of 
Streams and Wetlands to Downstream Waters: A Review and Synthesis of 
the Scientific Evidence (Final Report), EPA/600/R-14/475F (2015), 
available at https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=296414.
    \8\ Appendix A of the Technical Support Document contains a 
glossary of terms used in the document. Appendix B of the Technical 
Support Document contains the references cited in the document. 
Appendix C of the Technical Support Document is a list of citations 
that have been published since the Science Report and that contain 
findings relevant to the report's conclusions.
    \9\ Throughout this preamble, when the agencies refer to 
``science,'' that means foundational principles related to chemical, 
physical, and biological integrity, including biology, hydrology, 
geology, chemistry, and soil science; the Science Report; and the 
Technical Support Document for this rule.
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    The agencies' interpretation also reflects consideration of the 
statute as a whole, including both its objective in section 101(a) and 
its policies, such as that of section 101(b), which states in part that 
``it is the policy of Congress to recognize, preserve, and protect the 
primary responsibilities and rights of States to prevent, reduce, and 
eliminate pollution, [and] to plan the development and use (including 
restoration, preservation, and enhancement) of land and water 
resources.'' 33 U.S.C. 1251(b). The agencies find that the scope of 
Clean Water Act jurisdiction established in this final rule enhances 
States' ability to protect waters within their borders, such as by 
participating in the section 401 certification process and by providing 
input during the permitting process for out-of-state section 402 and 
404 permits that may affect their waters. See 33 U.S.C. 1341, 1342(b), 
1344(h)(1)(E). Indeed, in implementing and participating in the Clean 
Water Act's regulatory requirements and framework, States can have more 
powerful and holistic tools for addressing water quality than they 
would have in implementing state-only laws and regulations.
    Further, this rule is based on the agencies' conclusion that the 
significant nexus standard is consistent with the statutory text and 
legislative history, advances the objective of the Clean Water Act, is 
informed by the scientific record and Supreme Court case law, and 
appropriately considers the policies of the Act. The agencies have also 
determined that the relatively permanent standard is appropriate to 
include in this rule because, while it

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identifies only a subset of the ``waters of the United States,'' it 
also provides important efficiencies and additional clarity for 
regulators and the public by more readily identifying a subset of 
waters that will virtually always significantly affect paragraph (a)(1) 
waters. In addition, because this rule is founded upon a longstanding 
regulatory framework and reflects the agencies' experience and 
expertise, as well as updates in implementation tools and resources, it 
is generally familiar to the public and implementable. The 
clarifications in this rule, including the addition of exclusions that 
codify longstanding practice, and review of the advancements in 
implementation resources, tools, and scientific support (see section 
IV.G of this preamble) address many of the concerns raised in the past 
about timeliness and consistency of jurisdictional determinations under 
the Clean Water Act.
    By contrast, the agencies conclude that the 2020 NWPR, which 
substantially departed from prior rules defining ``waters of the United 
States,'' is incompatible with the objective of the Clean Water Act and 
inconsistent with the text of relevant provisions of the statute, the 
statute as a whole, relevant case law, and the best available science. 
The 2020 NWPR found jurisdiction primarily under the relatively 
permanent standard. The agencies have concluded that while the 
relatively permanent standard is administratively useful by more 
readily identifying a subset of waters that will virtually always 
significantly affect paragraph (a)(1) waters, it is insufficient as the 
sole test for Clean Water Act jurisdiction. Sole reliance on the 
relatively permanent standard's extremely limited approach has no 
grounding in the Clean Water Act's text, structure, or history. 
Limiting determinations to that standard alone upends an understanding 
of the Clean Water Act's coverage that has prevailed for nearly half a 
century. The relatively permanent standard as the exclusive 
jurisdictional test would seriously compromise the Clean Water Act's 
comprehensive scheme by denying any protection to tributaries that are 
not relatively permanent and adjacent wetlands that do not have a 
continuous surface connection to other jurisdictional waters. The 
exclusion of these waters runs counter to the science demonstrating how 
such waters can affect the integrity of larger downstream waters, 
including traditional navigable waters, the territorial seas, and 
interstate waters. The agencies have concluded that the relatively 
permanent standard should still be included in the rule in conjunction 
with the significant nexus standard because the subset of waters that 
meet the relatively permanent standard will virtually always have the 
requisite connection \10\ to traditional navigable waters, the 
territorial seas, or interstate waters to properly fall within the 
Clean Water Act's scope. The relatively permanent standard is also 
administratively useful as it more readily identifies a subset of 
waters that will virtually always significantly affect paragraph (a)(1) 
waters.
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    \10\ Throughout this preamble, the agencies' reference to a 
``connection'' to traditional navigable waters, the territorial 
seas, or interstate waters (when used without qualification such as 
``continuous surface connection'' or an ``unbroken surface or 
shallow subsurface connection'') includes all the types of 
connections relevant to either the relatively permanent standard or 
the significant nexus standard: physical (including hydrological), 
chemical, biological, or functional relationships (including where 
the water retains floodwaters or pollutants that would otherwise 
flow to the traditional navigable water, the territorial seas, or an 
interstate water). See Technical Support Document section III. A 
``requisite'' connection is one that satisfies either the relatively 
permanent or significant nexus standard.
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    Following a Federal district court decision vacating the 2020 NWPR 
on August 30, 2021, the agencies halted implementation of the 2020 NWPR 
and began interpreting ``waters of the United States'' consistent with 
the pre-2015 regulatory regime.\11\ For the reasons discussed more 
fully below, the agencies have decided that replacement of the 2020 
NWPR is vital.
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    \11\ See Pascua Yaqui Tribe v. EPA, 557 F. Supp. 3d 949 (D. 
Ariz. 2021); U.S. EPA, Current Implementation of Waters of the 
United States, https://www.epa.gov/wotus/current-implementation-waters-united-states; U.S. Army Corps of Engineers, Navigable Waters 
Protection Rule Vacatur (published January 5, 2022), https://www.usace.army.mil/Media/Announcements/Article/2888988/5-january-2022-navigable-waters-protection-rule-vacatur/.
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    Through the rulemaking process, the agencies have considered all 
timely public comments on the proposed rule, including changes that 
improve the clarity, implementability, and durability of the 
definition. The regulations established in this rule are founded on the 
familiar framework of the 1986 regulations and are generally consistent 
with the pre-2015 regulatory regime. They are fully consistent with the 
statute, informed by relevant Supreme Court decisions, and reflect the 
record before the agencies, including consideration of the best 
available science, as well as the agencies' expertise and experience 
implementing the pre-2015 regulatory regime. In addition, this final 
rule increases clarity and implementability by streamlining and 
restructuring the 1986 regulations and providing implementation 
guidance informed by sound science, implementation tools including 
modern assessment tools, and other resources.

II. General Information

A. What action are the agencies taking?

    In this action, the agencies are publishing a final rule defining 
``waters of the United States'' in 33 CFR 328.3 and 40 CFR 120.2.

B. What is the agencies' authority for taking this action?

    The authority for this action is the Federal Water Pollution 
Control Act, 33 U.S.C. 1251 et seq., including sections 301, 304, 311, 
401, 402, 404, and 501.

C. What are the incremental costs and benefits of this action?

    The agencies prepared the Economic Analysis for the Final ``Revised 
Definition of `Waters of the United States' '' Rule (hereinafter, 
``Economic Analysis for the Final Rule''), available in the rulemaking 
docket, for informational purposes to analyze the potential costs and 
benefits associated with this final action. This rule establishing the 
definition of ``waters of the United States'' does not by itself impose 
costs or benefits. Potential costs and benefits would only be incurred 
as a result of actions taken under existing Clean Water Act programs 
relying on the definition of ``waters of the United States'' (i.e., 
sections 303, 311, 401, 402, and 404). The agencies analyze the 
potential costs and benefits against two baselines: the current status 
quo and the vacated 2020 NWPR. The findings of this analysis for the 
primary baseline of the current status quo conclude that there are de 
minimis costs and benefits associated with this rulemaking. The 
findings of this analysis for the secondary baseline of the 2020 NWPR 
conclude that within the ranges of indirect costs and benefits 
considered, benefits consistently outweigh the costs. The analysis is 
summarized in section V.A of this preamble.

III. Background

A. Legal Background

1. The Clean Water Act
    Before passage of the Clean Water Act, the nation's waters were in 
``serious trouble, thanks to years of neglect, ignorance, and public 
indifference.'' H.R. Rep. No. 911, 92d Cong., 2d Sess. at 66 (1972). 
Congress enacted the Federal Water Pollution Control Act Amendments of 
1972, Public Law 92-500, 86 Stat. 816, as amended, 33 U.S.C. 1251 et 
seq., with the objective ``to restore and maintain the chemical, 
physical and biological integrity of the

[[Page 3008]]

Nation's waters.'' 33 U.S.C. 1251(a). The Clean Water Act was intended 
to address longstanding concerns regarding the quality of the nation's 
waters and the Federal Government's ability to respond to those 
concerns under existing law. A centerpiece of that comprehensive 
framework is the term ``navigable waters,'' which the Clean Water Act 
broadly defines as ``the waters of the United States, including the 
territorial seas.'' 33 U.S.C. 1362(7). Waters satisfying that 
definition are often called ``covered'' or ``jurisdictional'' waters 
because the term ``navigable waters'' appears in most of the Clean 
Water Act's key programs, including those for water quality standards, 
oil-spill prevention, and permits regulating the discharge of 
pollutants.
a. History of the Clean Water Act
    Prior to 1972, the Federal Government's authority to control and 
redress pollution in the nation's waters largely fell to the U.S. Army 
Corps of Engineers (Corps) under the Rivers and Harbors Act of 1899. 
While much of that statute focused on restricting obstructions to 
navigation on the nation's major waterways, section 13 of the statute 
made it unlawful to discharge refuse ``into any navigable water of the 
United States, or into any tributary of any navigable water from which 
the same shall float or be washed into such navigable water.'' 33 
U.S.C. 407. In 1948, Congress enacted the Federal Water Pollution 
Control Act of 1948, Public Law 80-845, 62 Stat. 1155 (June 30, 1948), 
to address interstate water pollution, and subsequently amended that 
statute in 1956, 1961, and 1965.\12\ These early versions of the 
statute that eventually became known as the Clean Water Act encouraged 
the development of pollution abatement programs, required States to 
develop water quality standards, and authorized the Federal Government 
to bring enforcement actions to abate water pollution. However, 
Congress subsequently concluded these authorities proved inadequate to 
address the decline in the quality of the nation's waters. See City of 
Milwaukee v. Illinois, 451 U.S. 304, 310 (1981) (citing S. Rep. No. 92-
414, p. 7 (1971)).
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    \12\ The 1948 Act was enacted ``in connection with the exercise 
of jurisdiction over the waterways of the Nation'' and focused 
specifically on the protection of water quality in interstate waters 
and tributaries of interstate waters. See Public Law 80-845, 62 
Stat. 1155 (1948). Congress's 1956 amendments to the Act 
strengthened measures for controlling pollution of interstate waters 
and their tributaries. Public Law 84-660, 70 Stat. 498 (1956). In 
1961, Congress amended the Act to substitute the term ``interstate 
or navigable waters'' for ``interstate waters.'' See Public Law 87-
88, 75 Stat. 208 (1961). Accordingly, beginning in 1961, the Act's 
provisions applied to all interstate waters and navigable waters and 
to the tributaries of each. See 33 U.S.C. 466a, 466g(a) (1964). The 
1965 amendments established the requirement that states develop 
water quality standards for interstate waters. Public Law 89-234, 79 
Stat. 903, 908, 909 (1965).
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    As a result, in 1972, Congress performed ``a `total restructuring' 
and `complete rewriting' of the existing'' statutory framework. Id. at 
317 (quoting legislative history of 1972 amendments). The Clean Water 
Act, which was passed as an amendment to the Federal Water Pollution 
Control Act, was described by its supporters as the first truly 
comprehensive Federal water pollution legislation. The ``major 
purpose'' of the Clean Water Act was ``to establish a comprehensive 
long-range policy for the elimination of water pollution.'' S. Rep. No. 
92-414, at 95 (1971), 2 Legislative History of the Water Pollution 
Control Act Amendments of 1972 (Committee Print compiled for the Senate 
Committee on Public Works by the Library of Congress), Ser. No. 93-1, 
p. 1511 (1971) (emphasis added). ``No Congressman's remarks on the 
legislation were complete without reference to [its] `comprehensive' 
nature.'' City of Milwaukee, 451 U.S. at 318. In passing the 1972 Act, 
Congress ``intended to repudiate limits that had been placed on federal 
regulation by earlier water pollution control statutes and to exercise 
its powers under the Commerce Clause to regulate at least some waters 
that would not be deemed `navigable' under the classical understanding 
of that term.'' Riverside Bayview, 474 U.S. at 133; see also Int'l 
Paper Co. v. Ouellette, 479 U.S. 481, 486 n.6 (1987).
    One of the Clean Water Act's principal tools to protect the 
integrity of the nation's waters is section 301(a), which generally 
prohibits ``the discharge of any pollutant by any person'' without a 
permit or other authorization under the Act. The terms ``discharge of a 
pollutant'' and ``discharge of pollutants'' are defined broadly to 
include ``any addition of any pollutant to navigable waters from any 
point source.'' 33 U.S.C. 1362(12). And ``navigable waters'' has a 
broad, specialized definition: ``the waters of the United States, 
including the territorial seas.'' Id. at 1362(7). Although Congress 
opted to carry over the term ``navigable waters'' from prior versions 
of the Federal Water Pollution Control Act, Congress broadened the 
definition of ``navigable waters'' to encompass all the ``waters of the 
United States.'' Id. The relevant House bill would have defined 
``navigable waters'' as the ``navigable waters of the United States, 
including the territorial seas.'' H.R. Rep. No. 911, 92d Cong., 2d 
Sess. 356 (1972) (emphasis omitted). But in conference the word 
``navigable'' was deleted from that definition, and the conference 
report urged that the term ``be given the broadest possible 
constitutional interpretation.'' S. Conf. Rep. No. 1236, 92d Cong., 2d 
Sess. 144 (1972). Further, the Senate Report stated that ``navigable 
waters'' means ``the navigable waters of the United States, portions 
thereof, tributaries thereof, and includes the Territorial Seas and the 
Great Lakes.'' S. Rep. No. 92-414, at 77 (1971), as reprinted in 1972 
U.S.C.C.A.N. 3668, 3742-43 (emphasis added). The Senate Report 
accompanying the 1972 Act also explained that ``[w]ater moves in 
hydrologic cycles and it is essential that the discharge of pollutants 
be controlled at the source.'' Id.
    In 1977, Congress substantially amended the Clean Water Act while 
leaving unchanged the 1972 definition of ``navigable waters.'' See 
Clean Water Act of 1977 (1977 Act), Public Law 95-217, 91 Stat. 1566. 
In the run-up to those amendments, Congress considered proposals to 
amend section 404, which requires a permit for discharges of dredged or 
fill material into ``waters of the United States,'' and debate on those 
proposals ``centered largely on the issue of wetlands preservation.'' 
SWANCC, 531 U.S. at 170 (citation omitted). The legislative proposal 
followed the Corps' 1975 rulemaking, which defined the scope of 
``waters of the United States'' to cover all of the following waters, 
but phased Corps' regulation of discharges of dredged or fill material 
into these waters in three phases: first, into ``coastal waters and 
coastal wetlands contiguous or adjacent thereto or into inland 
navigable waters of the United States and freshwater wetlands 
contiguous or adjacent thereto;'' second, into ``primary tributaries, 
freshwater wetlands contiguous or adjacent to primary tributaries, and 
lakes;'' and third, ``into intrastate lakes, rivers and streams 
landward to their ordinary high water mark''. 40 FR 31320, 31324, 31326 
(July 25, 1975); see section III.A.2 of this preamble infra for further 
discussion of the phased rulemaking through which the Corps established 
a definition of ``waters of the United States'' and the dates when the 
Corps began regulating activities under that definition. The House 
passed a bill that would have limited the waters and adjacent wetlands 
to which section 404 applies. H.R. 3199, 95th Cong., section 16 (1977). 
Many legislators objected, with one characterizing the proposed 
limitation as an ``open invitation'' to pollute other

[[Page 3009]]

wetlands. 123 Cong. Rec. 26,725 (1977) (statement of Sen. Hart); see 
id. at 26,714-26,716. The Senate ultimately rejected the proposal. Id. 
at 26,728; cf. S. Rep. No. 370, 95th Cong., 1st Sess. 10 (1977).
    Congress instead modified the Clean Water Act in other respects. 
Rather than alter the geographic reach of section 404 in 1977, Congress 
amended the statute by exempting certain activities--for example, 
certain agricultural and silvicultural activities--from the permit 
requirements of section 404. See 33 U.S.C. 1344(f). The amendments also 
authorized the use of ``general permits'' to streamline the permitting 
process.\13\ See id. at 1344(e). Finally, the 1977 Act established for 
the first time a mechanism by which a State, rather than the Corps, 
could assume responsibility to administer the section 404 permitting 
program. Id. at 1344(g)(1). In so doing, however, Congress limited 
States' potential jurisdiction to waters ``other than those waters 
which are presently used, or are susceptible to use in their natural 
condition or by reasonable improvement as a means to transport 
interstate or foreign commerce shoreward to their ordinary high water 
mark, including all waters which are subject to the ebb and flow of the 
tide shoreward to their mean high water mark, or mean higher high water 
mark on the west coast, including wetlands adjacent thereto.'' Id. The 
Corps retains jurisdiction to issue permits in those waters. See 
section IV.A.2.b for additional analysis of the Corps' regulations, the 
text of the 1977 amendments, and their legislative history for purposes 
of construing the scope of ``waters of the United States.''
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    \13\ Whereas individual permits are issued directly to an 
individual discharger, a ``general permit'' may provide coverage for 
multiple dischargers. See also preamble section III.A.1.b for 
additional discussion of general permits.
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b. Clean Water Act Programs
    The term ``navigable waters'' is used in most of the key programs 
established by the Clean Water Act, including the section 402 National 
Pollutant Discharge Elimination System (NPDES) permit program; the 
section 404 permit program for dredged or fill material; the section 
311 oil spill prevention, preparedness, and response program; \14\ the 
water quality standards, impaired waters, and total maximum daily load 
programs under section 303; and the section 401 Tribal and State water 
quality certification process. While there is only one definition of 
``waters of the United States'' for purposes of the Clean Water Act, 
there may be other statutory factors that define the reach of a 
particular Clean Water Act program or provision.\15\
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    \14\ While Clean Water Act section 311 uses the phrase 
``navigable waters of the United States,'' EPA has interpreted it to 
have the same breadth as the phrase ``navigable waters'' used 
elsewhere in section 311, and in other sections of the Clean Water 
Act. See United States v. Texas Pipe Line Co., 611 F.2d 345, 347 
(10th Cir. 1979); United States v. Ashland Oil & Transp. Co., 504 
F.2d 1317, 1324-25 (6th Cir. 1974). In 2002, EPA revised its 
regulations defining ``waters of the United States'' in 40 CFR part 
112 to ensure that the rule's language was consistent with the 
regulatory language used in other Clean Water Act programs. Oil 
Pollution Prevention & Response; Non-Transportation-Related Onshore 
& Offshore Facilities, 67 FR 47042 (July 17, 2002). A district court 
vacated the rule for failure to comply with the Administrative 
Procedure Act and reinstated the prior regulatory language. American 
Petroleum Ins. v. Johnson, 541 F. Supp. 2d 165 (D.D.C. 2008). 
However, EPA interprets ``navigable waters of the United States'' in 
Clean Water Act section 311(b), in both the pre-2002 regulations and 
the 2002 rule, to have the same meaning as ``navigable waters'' in 
Clean Water Act section 502(7).
    \15\ For example, the Clean Water Act section 402 permit program 
regulates discharges of pollutants from ``point sources'' to 
``navigable waters'' whether the pollutants reach jurisdictional 
waters directly or indirectly. See Rapanos, 547 U.S. at 743 
(plurality); see also County of Maui, Hawaii v. Hawaii Wildlife 
Fund, 140 S. Ct. 1462, 1476 (2020) (holding that the statute also 
requires a permit ``when there is the functional equivalent of a 
direct discharge''). Section 402 also regulates ``any addition of 
any pollutant to the waters of the contiguous zone or the ocean from 
any point source other than a vessel or other floating craft.'' See 
33 U.S.C. 1362(12). As another example, section 311 applies to 
``discharges of oil or hazardous substances into or upon the 
navigable waters of the United States, adjoining shorelines, or into 
or upon the waters of the contiguous zone, or in connection with 
activities under the Outer Continental Shelf Lands Act [43 U.S.C. 
1331 et seq.] or the Deepwater Port Act of 1974 [33 U.S.C. 1501 et 
seq.], or which may affect natural resources belonging to, 
appertaining to, or under the exclusive management authority of the 
United States (including resources under the Magnuson-Stevens 
Fishery Conservation and Management Act [16 U.S.C. 1801 et seq.]).'' 
33 U.S.C. 1321(b)(1).
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    EPA administers the Clean Water Act except as otherwise explicitly 
provided. 33 U.S.C. 1251(d). The United States Attorney General long 
ago determined that the ``ultimate administrative authority to 
determine the reach of the term `navigable waters' for purposes of 
Sec.  404'' resides with EPA. 43 Op. Att'y Gen. 197 (1979). The Act 
provides for the Federal Government to implement some Clean Water Act 
programs, and it gives direct grants of authority to authorized Tribes 
as well as States for implementation and enforcement of others. In some 
cases, the Act provides authorized Tribes and States the option to take 
on certain Clean Water Act programs.\16\ Eligible Tribes or States 
implement the section 401 program and may request approval by EPA to 
administer a Clean Water Act section 402 or 404 
program.17 18 Moreover, consistent with the Clean Water Act, 
Tribes and States retain authority to implement their own programs to 
protect the waters in their jurisdiction more broadly and more 
stringently than the Federal Government. Section 510 of the Clean Water 
Act provides that, unless expressly stated, nothing in the Clean Water 
Act precludes or denies the right of any Tribe or State to establish 
more protective standards or limits than the Clean Water Act.\19\ For 
example, many Tribes and States regulate groundwater, and some others 
protect vital wetlands that may be outside the scope of the Clean Water 
Act.
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    \16\ The Clean Water Act defines ``state'' as ``a State, the 
District of Columbia, the Commonwealth of Puerto Rico, the Virgin 
Islands, Guam, American Samoa, the Commonwealth of the Northern 
Mariana Islands, and the Trust Territory of the Pacific Islands.'' 
33 U.S.C. 1362(3). Clean Water Act section 518(e), which is part of 
the 1987 amendments to the Act, authorizes EPA to treat eligible 
federally recognized Tribes in a similar manner as a State for 
implementing and managing certain environmental programs. 33 U.S.C. 
1377(e).
    \17\ All States and 79 Tribes have authority to implement 
section 401 water quality certification programs. Currently 47 
States and one territory have authority to administer all or 
portions of the section 402 NPDES program for ``waters of the United 
States.'' All States and 47 Tribes have established water quality 
standards pursuant to section 303 of the Clean Water Act, which form 
a legal basis for limitations on discharges of pollutants to 
``waters of the United States.'' Three States are authorized to 
administer a section 404 program for certain waters in their 
boundaries.
    \18\ As noted in section III.A.1.a of this preamble, when a 
Tribe or State assumes a section 404 program, the Corps retains 
permitting authority over certain waters. The scope of Clean Water 
Act jurisdiction as defined by ``waters of the United States'' is 
distinct from the scope of waters over which the Corps retains 
authority following Tribal or State assumption of the section 404 
program. Corps-retained waters are identified during approval of a 
Tribal or State section 404 program, and any modifications are 
approved through a formal EPA process. 40 CFR 233.36. This rule does 
not address the scope of Corps-retained waters, and nothing in this 
rule should affect the process for determining the scope of Corps-
retained waters.
    \19\ Congress has provided for eligible Tribes to administer 
Clean Water Act programs over their reservations and expressed a 
preference for Tribal regulation of surface water quality on 
reservations to ensure compliance with the goals of the statute. See 
33 U.S.C. 1377; 56 FR 64876, 64878-79 (December 12, 1991). In 
addition, Tribes may establish more protective standards or limits 
under Tribal law that may be more stringent than the Federal Clean 
Water Act. Where appropriate, references to States in this preamble 
may also include eligible Tribes.
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    In addition to section 301(a) which regulates discharges of 
pollutants to jurisdictional waters, many other provisions of the Clean 
Water Act operate based on the definition of ``waters of the United 
States.'' For example, under section 303, water quality standards and 
total maximum daily loads are not required under the Clean Water Act 
for waters that are not ``waters of the United States,'' and Tribes and 
States have no authority to provide certifications under section 401

[[Page 3010]]

with water quality conditions for a permit or license issued by a 
Federal agency for an activity that does not result in a discharge to 
``waters of the United States.''
    Under section 402 of the Clean Water Act, an NPDES permit is 
required where a point source discharges a pollutant to ``waters of the 
United States.'' \20\ Clean Water Act section 404 requires a permit 
before dredged or fill material may be discharged to ``waters of the 
United States,'' with regulatory exemptions for certain farming, 
ranching, and forestry activities. No section 404 permits are required 
for discharging dredged or fill material into waters or features that 
are not ``waters of the United States.''
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    \20\ The term ``point source'' is defined in Clean Water Act 
section 502(14) and 40 CFR 122.2 to include ``any discernible, 
confined and discrete conveyance . . . from which pollutants are or 
may be discharged.'' This definition specifically excludes return 
flows from irrigated agriculture and agricultural stormwater runoff. 
See also supra note 15 (discussing discharges of pollutants subject 
to the section 402 program).
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    Section 303(c) of the Clean Water Act requires States to establish 
water quality standards for ``waters of the United States.'' States 
must periodically review their water quality standards and modify or 
adopt standards as required by the Clean Water Act or as otherwise 
appropriate. States must submit new or revised standards for EPA 
review. Water quality standards are the foundation for a wide range of 
programs under the Clean Water Act. They serve multiple purposes 
including establishing the water quality goals for a specific 
waterbody, or portion thereof, and providing the regulatory basis for 
establishing water quality-based effluent limits beyond the technology-
based levels of treatment required by the Clean Water Act. Water 
quality standards also serve as a target for Clean Water Act 
restoration goals such as total maximum daily loads.
    Under Clean Water Act section 303(d) and EPA's implementing 
regulations, States are required to assemble and evaluate all existing 
and readily available water quality-related data and information and to 
submit to EPA every two years a list of impaired waters that require 
total maximum daily loads. For waters identified on a 303(d) list, 
States establish total maximum daily loads for all pollutants 
preventing or expected to prevent attainment of water quality 
standards. Section 303(d) applies to ``waters of the United States.'' 
Non-jurisdictional waterbodies are not required to be assessed or 
otherwise identified as impaired. Total maximum daily load restoration 
plans likewise apply only to ``waters of the United States.''
    Clean Water Act section 311 and the Oil Pollution Act (OPA) of 1990 
authorize the Oil Spill Liability Trust Fund (OSLTF) to pay for or 
reimburse costs of assessing and responding to oil spills to ``waters 
of the United States'' or adjoining shorelines or the Exclusive 
Economic Zone.\21\ The OSLTF allows an immediate response to a spill, 
including containment, countermeasures, cleanup, and disposal 
activities. The OSLTF can only reimburse Tribes or States for cleanup 
costs and damages to businesses and citizens (e.g., lost wages and 
damages) for spills affecting waters subject to Clean Water Act 
jurisdiction. EPA also lacks authority under the Clean Water Act to 
take enforcement actions based on spills solely affecting waters not 
subject to Clean Water Act jurisdiction under section 311(b). Moreover, 
section 311's requirements for oil spill and prevention plans only 
apply to those facilities where there is a reasonable expectation that 
an oil discharge could reach a jurisdictional water or adjoining 
shoreline or the Exclusive Economic Zone.
---------------------------------------------------------------------------

    \21\ See 33 U.S.C. 1321(b) for the full jurisdictional scope of 
Clean Water Act section 311.
---------------------------------------------------------------------------

    The scope of facilities required to prepare oil spill prevention 
and response plans is also affected by the definition of ``waters of 
the United States.'' EPA-regulated oil storage facilities with storage 
capacities greater than 1,320 gallons (except farms) that have a 
reasonable expectation of an oil discharge to ``waters of the United 
States'' or adjoining shorelines \22\ are required to prepare and 
implement spill prevention plans. High-risk oil storage facilities that 
meet certain higher storage thresholds and related harm factors are 
required to prepare and submit oil spill preparedness plans to EPA for 
review. The U.S. Coast Guard and Department of Transportation also 
require oil spill response plans under their respective authorities. 
However, section 311 spill prevention and preparedness plan 
requirements do not apply to a facility if there is no reasonable 
expectation that an oil discharge from that facility could reach a 
jurisdictional water or adjoining shoreline or the Exclusive Economic 
Zone.
---------------------------------------------------------------------------

    \22\ See supra note 14.
---------------------------------------------------------------------------

    Clean Water Act section 401 provides authorized Tribes and States 
an opportunity to address the proposed aquatic resource impacts of 
federally issued permits and licenses. The definition of ``waters of 
the United States'' affects where Federal permits and licenses are 
required and thus where section 401 certification applies. Section 401 
prohibits Federal agencies from issuing permits or licenses for 
activities that may result in a discharge to ``waters of the United 
States'' until after the State or authorized Tribe where the discharge 
would originate has granted or waived water quality certification.
    The fact that a resource meets the definition of ``waters of the 
United States'' does not mean that activities such as farming, 
construction, infrastructure development, or resource extraction cannot 
occur in or near the resource at hand. For example, the Clean Water Act 
exempts a number of activities from permitting or from the definition 
of ``point source,'' including agricultural storm water and irrigation 
return flows. See 33 U.S.C. 1342(l)(2), 1362(14). As discussed above, 
since 1977 the Clean Water Act in section 404(f) has exempted 
activities such as many ``normal farming, silviculture, and ranching 
activities'' from the section 404 permitting requirement, including 
seeding, harvesting, cultivating, planting, and soil and water 
conservation practices. Id. at 1344(f)(1). This rule does not affect 
these statutory exemptions.
    In addition, permits are routinely issued under Clean Water Act 
sections 402 and 404 to authorize certain discharges to ``waters of the 
United States.'' Further, under both permitting programs, the agencies 
have established general permits for a wide variety of activities that 
have minimal impacts to waters. General permits provide dischargers 
with knowledge about applicable requirements before dischargers may 
obtain coverage under them. Furthermore, obtaining coverage under a 
general permit is typically quicker than obtaining coverage under an 
individual permit, with coverage under a general permit often occurring 
immediately (depending on how the permit is written) or after a short 
waiting period. The permitting authority \23\ generally works with 
permit applicants to ensure that activities can occur without harming 
the integrity of the nation's waters. Thus, the permitting programs 
allow for discharges to ``waters of the United States'' to occur while 
also ensuring that those discharges meet statutory and regulatory 
requirements designed to protect water quality.
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    \23\ Generally, the permitting authority is either EPA or an 
authorized State for the NPDES program and either the Corps or an 
authorized State for the section 404 program. No eligible Tribes 
have authority to administer a Clean Water Act section 402 or 
section 404 program at this time.

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[[Page 3011]]

    In issuing section 404 permits, the Corps or authorized State works 
with the applicant to avoid, minimize, and compensate for any 
unavoidable impacts to ``waters of the United States.'' For most 
discharges that ``will cause only minimal adverse environmental 
effects,'' a general permit (e.g., a ``nationwide'' permit) may be 
suitable. 33 U.S.C. 1344(e)(1). General permits are issued on a 
nationwide, regional, or State basis for particular categories of 
activities. While some general permits require the applicant to submit 
a pre-construction notification to the Corps or the State, others allow 
the applicant to proceed with no formal notification. The general 
permit process allows certain activities to proceed with little or no 
delay, provided the general or specific conditions for the general 
permit are met. For example, minor road construction activities, 
utility line backfill, and minor discharges for maintenance can be 
considered for a general permit, where the activity meets the threshold 
limits and only results in minimal impacts, individually and 
cumulatively. Tribes and States can also have a role in Corps section 
404 permit decisions, through State Programmatic General Permits 
(SPGPs), Regional General Permits (RGPs), and water quality 
certification.
    Property owners may obtain a jurisdictional determination from the 
Corps.\24\ A jurisdictional determination is a written Corps document 
indicating whether a water is subject to regulatory jurisdiction under 
section 404 of the Clean Water Act (33 U.S.C. 1344) or under section 9 
or 10 of the Rivers and Harbors Act of 1899 (33 U.S.C. 401 et seq.). 
Jurisdictional determinations are identified as either preliminary or 
approved. An approved jurisdictional determination (AJD) is ``a Corps 
document stating the presence or absence of waters of the United States 
on a parcel or a written statement and map identifying the limits of 
waters of the United States on a parcel.'' 33 CFR 331.2. An approved 
jurisdictional determination is administratively appealable and is a 
final agency action subject to judicial review. U.S. Army Corps of 
Engineers v. Hawkes Co., Inc., 578 U.S. 590 (2016). A preliminary 
jurisdictional determination (PJD) is a non-binding ``written 
indication that there may be waters of the United States on a parcel or 
indications of the approximate location(s) of waters of the United 
States on a parcel.'' 3 CFR 331.2. An applicant can elect to use a PJD 
to voluntarily waive or set aside questions regarding Clean Water Act 
jurisdiction over a particular site and thus move forward assuming all 
waters will be treated as jurisdictional without making a formal 
determination. The Corps does not charge a fee for these jurisdictional 
determinations. See 33 CFR 325.1 (omitting mention of fees for 
jurisdictional determinations); Regulatory Guidance Letter 16-01 (2016) 
(stating that such determinations are issued as a ``public service'').
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    \24\ When a Tribe, State, or territory is approved to administer 
the Clean Water Act section 404 program for certain waters, it is 
responsible for decisions on whether or not a section 404 permit is 
required.
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2. The 1986 Regulations Defining ``Waters of the United States''
    In 1973, EPA published regulations defining ``navigable waters'' to 
include traditional navigable waters; tributaries of traditional 
navigable waters; interstate waters; and intrastate lakes, rivers, and 
streams used in interstate commerce. 38 FR 13528, 13528-29 (May 22, 
1973). The Corps published regulations in 1974 defining the term 
``navigable waters'' for purposes of section 404 to mean ``those waters 
of the United States which are subject to the ebb and flow of the tide, 
and/or are presently, or have been in the past, or may be in the future 
susceptible for use for purposes of interstate or foreign commerce.'' 
39 FR 12115, 12119 (April 3, 1974); 33 CFR 209.120(d)(1) (1974); see 
also 33 CFR 209.260(e)(1) (1974) (explaining that ``[i]t is the water 
body's capability of use by the public for purposes of transportation 
or commerce which is the determinative factor'').\25\
---------------------------------------------------------------------------

    \25\ See Lance Wood, Don't Be Misled: CWA Jurisdiction Extends 
to All Non-Navigable Tributaries of the Traditional Navigable Waters 
and to Their Adjacent Wetlands, 34 Envtl. L. Rptr. (Envtl. L. Inst.) 
10,187 (2004) (explaining history and limitations of the 1974 Corps 
regulation as an interpretation of the scope of the Clean Water 
Act).
---------------------------------------------------------------------------

    Around the same time, several Federal courts found that limiting 
``waters of the United States'' to those that are navigable-in-fact is 
an unduly restrictive reading of the Act. See, e.g., United States v. 
Holland, 373 F. Supp. 665, 670-676 (M.D. Fla. 1974) (``Holland''); 
Natural Resources Defense Council, Inc. v. Callaway, 392 F. Supp. 685, 
686 (D.D.C. 1975) (``Callaway''). EPA and the House Committee on 
Government Operations agreed with the decision in Holland.\26\ In 
Callaway, the court held that in the Clean Water Act, Congress had 
``asserted federal jurisdiction over the nation's waters to the maximum 
extent permissible under the Commerce Clause of the Constitution. 
Accordingly, as used in the [Federal] Water [Pollution Control] Act, 
the term [`navigable waters'] is not limited to the traditional tests 
of navigability.'' The court ordered the Corps to publish new 
regulations ``clearly recognizing the full regulatory mandate of the 
[Federal] Water [Pollution Control] Act.'' Callaway, 392 F. Supp. at 
686.
---------------------------------------------------------------------------

    \26\ EPA expressed the view that ``the Holland decision provides 
a necessary step for the preservation of our limited wetland 
resources,'' and that ``the [Holland] court properly interpreted the 
jurisdiction granted under the [Clean Water Act] and Congressional 
power to make such a grant.'' See section 404 of the Federal Water 
Pollution Control Act Amendments of 1972: Hearings Before the Senate 
Comm. on Pub. Works, 94th Cong., 2d Sess. 349 (1976) (letter dated 
June 19, 1974, from Russell E. Train, Administrator of EPA, to Lt. 
Gen. W.C. Gribble, Jr., Chief of Corps of Engineers). Shortly 
thereafter, the House Committee on Government Operations discussed 
the disagreement between the two agencies (as reflected in EPA's 
June 19 letter) and concluded that the Corps should adopt the 
broader view of the term ``waters of the United States'' taken by 
EPA and by the court in Holland. See H.R. Rep. No. 1396, 93d Cong., 
2d Sess. 23-27 (1974). The Committee urged the Corps to adopt a new 
definition that ``complies with the congressional mandate that this 
term be given the broadest possible constitutional interpretation.'' 
Id. at 27 (internal quotation marks omitted).
---------------------------------------------------------------------------

    In response to the district court's order in Callaway, the Corps 
promulgated interim final regulations providing for a phased-in 
expansion of its section 404 jurisdiction. 40 FR 31320 (July 25, 1975); 
see 33 CFR 209.120(d)(2), (e)(2) (1976). The court required that the 
Corps put forth a new definition within a short timeframe. The 
regulatory phased-in approach was to ensure enough time for the Corps 
to build up their resources to implement the expanded jurisdiction and 
workload. Thus, the phases did not mean all of the waters in the final 
regulation were not ``waters of the United States,'' but rather 
established when the Corps would begin regulating activities within 
each type of jurisdictional water.\27\ The interim regulations revised 
the definition of ``waters of the United States'' to include waters not 
covered by the other regulatory provisions. 33 CFR 209.120(d)(2)(i) 
(1976).\28\ On July 19, 1977, the Corps published its final 
regulations, in which it revised the 1975 interim regulations to 
clarify many of

[[Page 3012]]

the definitional terms for purposes of section 404. 42 FR 37122 (July 
19, 1977). The 1977 final regulations defined the term ``waters of the 
United States'' to include, inter alia, ``isolated wetlands and lakes, 
intermittent streams, prairie potholes, and other waters that are not 
part of a tributary system to interstate waters or to navigable waters 
of the United States, the degradation or destruction of which could 
affect interstate commerce.'' 33 CFR 323.2(a)(5) (1978); see also 40 
CFR 122.3 (1979).\29\
---------------------------------------------------------------------------

    \27\ See Wood, supra note 25.
    \28\ Phase I, which was immediately effective, included coastal 
waters and traditional inland navigable waters and their adjacent 
wetlands. 40 FR 31321, 31324, 31326 (July 25, 1975). Phase II, which 
took effect after July 1, 1976, extended the Corps' jurisdiction to 
lakes and certain tributaries of Phase I waters, as well as wetlands 
adjacent to the lakes and certain tributaries. Id. Phase III, which 
took effect after July 1, 1977, extended the Corps' jurisdiction to 
all remaining areas encompassed by the regulations, including 
``intermittent rivers, streams, tributaries, and perched wetlands 
that are not contiguous or adjacent to navigable waters.'' Id. at 
31325; see also 42 FR 37124 (July 19, 1977) (describing the three 
phases).
    \29\ An explanatory footnote published in the Code of Federal 
Regulations stated that this paragraph ``incorporates all other 
waters of the United States that could be regulated under the 
Federal government's Constitutional powers to regulate and protect 
interstate commerce.'' 33 CFR 323.2(a)(5), at 616 n.2 (1978).
---------------------------------------------------------------------------

    In 1986, the Corps consolidated and recodified its regulatory 
provisions defining ``waters of the United States'' for purposes of 
implementing the section 404 program. See 51 FR 41206, 41216-17 
(November 13, 1986). These regulations reflected the interpretation of 
both agencies. While EPA and the Corps also have separate regulations 
defining the statutory term ``waters of the United States,'' their 
interpretations, reflected in the 1986 regulations, were identical and 
remained largely unchanged from 1977 to 2015. See 42 FR 37122, 37124, 
37127 (July 19, 1977).\30\ EPA's comparable regulations were recodified 
in 1988 (53 FR 20764 (June 6, 1988)), and both agencies added an 
exclusion for prior converted cropland in 1993 (58 FR 45008, 45031 
(August 25, 1993)). For convenience, the agencies in this preamble will 
generally cite the Corps' longstanding regulations and will refer to 
``the 1986 regulations'' as including EPA's comparable regulations and 
the 1993 addition of the exclusion for prior converted cropland.
---------------------------------------------------------------------------

    \30\ Multiple provisions in the Code of Federal Regulations 
contained the definition of the phrases ``waters of the United 
States'' and ``navigable waters'' for purposes of implementing the 
Clean Water Act, 33 U.S.C. 1362(7), and other water pollution 
protection statutes such as the Oil Pollution Act, 33 U.S.C. 
2701(21). Some EPA definitions were added after 1986, but each 
conformed to the 1986 regulations except for variations in the waste 
treatment system exclusion. See, e.g., 55 FR 8666 (March 8, 1990); 
73 FR 71941 (November 26, 2008).
---------------------------------------------------------------------------

    The 1986 regulations define ``waters of the United States'' as 
follows (33 CFR 328.3 (2014)): \31\
---------------------------------------------------------------------------

    \31\ There are some variations in the waste treatment system 
exclusion across EPA's regulations defining ``waters of the United 
States.'' The placement of the waste treatment system and prior 
converted cropland exclusions also varies in EPA's regulations.
---------------------------------------------------------------------------

    (a) The term ``waters of the United States'' means:
    1. 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;
    2. All interstate waters including interstate wetlands;
    3. All other waters such as intrastate 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 or could affect 
interstate or foreign commerce including any such waters:
    i. Which are or could be used by interstate or foreign travelers 
for recreational or other purposes; or
    ii. From which fish or shellfish are or could be taken and sold in 
interstate or foreign commerce; or
    iii. Which are used or could be used for industrial purposes by 
industries in interstate commerce;
    4. All impoundments of waters otherwise defined as waters of the 
United States under this definition;
    5. Tributaries of waters identified in paragraphs (a)(1) through 
(4) of this section;
    6. The territorial seas; and
    7. Wetlands adjacent to waters (other than waters that are 
themselves wetlands) identified in paragraphs (a)(1) through (6) of 
this section.
    8. Waters of the United States do not include 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.
    Waste treatment systems, including treatment ponds or lagoons 
designed to meet the requirements of Clean Water Act (other than 
cooling ponds as defined in 40 CFR 423.11(m) which also meet the 
criteria of this definition) are not waters of the United States.
    See section I.B of the Economic Analysis for the Final Rule for a 
comparison of regulatory categories between the pre-2015 regulatory 
regime, the 2020 NWPR, and this rule.
3. U.S. Supreme Court Decisions
    The U.S. Supreme Court first addressed the scope of ``waters of the 
United States'' protected by the Clean Water Act in United States v. 
Riverside Bayview Homes, 474 U.S. 121 (1985) (``Riverside Bayview''), 
which involved wetlands adjacent to a traditional navigable water in 
Michigan. In a unanimous opinion, the Court reversed the Sixth Circuit 
Court of Appeals and held that court had erred when it imposed a 
limitation requiring inundation or ``frequent flooding'' of wetlands by 
the adjacent body of water for the wetlands to be jurisdictional when 
such a limitation was required by neither the regulation nor the Clean 
Water Act. Id. at 129, 134. The Supreme Court then deferred to the 
Corps' judgment that adjacent wetlands ``that form the border of or are 
in reasonable proximity to'' other ``waters of the United States'' are 
``inseparably bound up with the `waters' of the United States,'' thus 
concluding that ``adjacent wetlands may be defined as waters under the 
Act.'' Riverside Bayview, 474 U.S. at 134. The Court observed that the 
objective of the Clean Water Act to restore the integrity of the 
nation's waters ``incorporated a broad, systemic view of the goal of 
maintaining and improving water quality . . . . Protection of aquatic 
ecosystems, Congress recognized, demanded broad federal authority to 
control pollution, for `[water] moves in hydrologic cycles and it is 
essential that discharge of pollutants be controlled at the source.' '' 
Id. at 132-33 (citing S. Rep. 92-414 (1972)). The Court then stated: 
``In keeping with these views, Congress chose to define the waters 
covered by the Act broadly. Although the Act prohibits discharges into 
`navigable waters,' see CWA [sections] 301(a), 404(a), 502(12), 33 
U.S.C. [sections] 1311(a), 1344(a), 1362(12), the Act's definition of 
`navigable waters' as `the waters of the United States' makes it clear 
that the term `navigable' as used in the Act is of limited import.'' 
Id. at 133.
    The Court also recognized that ``[i]n determining the limits of its 
power to regulate discharges under the Act, the Corps must necessarily 
choose some point at which water ends and land begins. Our common 
experience tells us that this is often no easy task: the transition 
from water to solid ground is not necessarily or even typically an 
abrupt one. Rather, between open waters and dry land may lie shallows, 
marshes, mudflats, swamps, bogs--in short, a huge array of areas that 
are not wholly aquatic but nevertheless fall far short of being dry 
land. Where on this continuum to find the limit of `waters' is far from 
obvious.'' Id. at 132. The Court then deferred to the agencies' 
interpretation: ``In view of the breadth of federal regulatory 
authority contemplated by the Act itself and the inherent difficulties 
of defining precise bounds to regulable waters, the Corps' ecological 
judgment about the relationship between waters and their adjacent 
wetlands provides an adequate basis for a legal judgment that adjacent

[[Page 3013]]

wetlands may be defined as waters under the Act.'' Id. at 134. The 
Court further stated, ``[i]f it is reasonable for the Corps to conclude 
that in the majority of cases, adjacent wetlands have significant 
effects on water quality and the aquatic ecosystem, its definition can 
stand.'' Id. at 135 n.9. The Court expressly reserved the question of 
whether the Clean Water Act applies to ``wetlands that are not adjacent 
to open waters.'' Id. at 131 n.8.
    The Supreme Court again addressed the issue of Clean Water Act 
jurisdiction over ``waters of the United States'' in Solid Waste Agency 
of Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159 
(2001) (``SWANCC''). A 5-4 Court in SWANCC held that the use of 
``nonnavigable, isolated, intrastate waters'' by migratory birds was 
not by itself a sufficient basis for the exercise of Federal authority 
under the Clean Water Act. SWANCC, 531 U.S. at 172. The Court noted 
that in Riverside Bayview, it had ``found that Congress' concern for 
the protection of water quality and aquatic ecosystems indicated its 
intent to regulate wetlands `inseparably bound up with the ``waters'' 
of the United States''' and that ``[i]t was the significant nexus 
between the wetlands and `navigable waters' that informed [the Court's] 
reading of the Clean Water Act'' in that case. Id. at 167.
    While recognizing that Riverside Bayview had found the term 
``navigable'' to be of limited import, the Court in SWANCC noted that 
the term ``navigable'' could not be read entirely out of the Act. Id. 
at 172 (``We said in Riverside Bayview Homes that the word `navigable' 
in the statute was of `limited import' and went on to hold that 
[section] 404(a) extended to non-navigable wetlands adjacent to open 
waters. But it is one thing to give a word limited effect and quite 
another to give it no effect whatever. The term `navigable' has at 
least the import of showing us what Congress had in mind as its 
authority for enacting the CWA: its traditional jurisdiction over 
waters that were or had been navigable in fact or which could 
reasonably be so made.'' (citations omitted)).
    The Corps asserted authority in this instance based on an 
interpretation of the regulations (known as the ``Migratory Bird 
Rule'') that waters used as habitat for migratory birds were 
jurisdictional. The Court found that the exercise of Clean Water Act 
regulatory authority over discharges into the ponds based on their use 
by migratory birds raised ``significant constitutional questions.'' Id. 
at 173. The Court explained that ``[w]here an administrative 
interpretation of a statute invokes the outer limits of Congress' 
power, we expect a clear indication that Congress intended that 
result.'' Id. at 172. This is particularly true ``where the 
administrative interpretation alters the federal-state framework by 
permitting federal encroachment upon a traditional state power.'' Id. 
at 173 (citing United States v. Bass, 404 U.S. 336, 349 (1971)). The 
Court concluded that ``the `Migratory Bird Rule' is not fairly 
supported by the CWA.'' Id. at 167.
    Five years after SWANCC, the Court again addressed the Clean Water 
Act term ``waters of the United States'' in Rapanos v. United States, 
547 U.S. 715 (2006) (``Rapanos''). Rapanos involved two consolidated 
cases in which the Clean Water Act had been applied to wetlands 
adjacent to tributaries, that are not themselves navigable-in-fact, of 
traditional navigable waters. Although the Court remanded the Court of 
Appeals' finding of Clean Water Act jurisdiction, the plurality opinion 
and Justice Kennedy's concurrence disagreed on the proper test to 
apply. Despite this disagreement, all nine members of the Court agreed 
that the term ``waters of the United States'' encompasses some waters 
that are not navigable in the traditional sense. Id. at 731 (Scalia, 
J., plurality opinion) (``We have twice stated that the meaning of 
`navigable waters' in the Act is broader than the traditional 
understanding of that term, SWANCC, 531 U.S. at 167, 121 S. Ct. 675, 
148 L. Ed. 2d 576; Riverside Bayview, 474 U.S. at 133, 106 S. Ct. 455, 
88 L. Ed. 2d 419.'').
    A four-Justice plurality in Rapanos interpreted the term ``waters 
of the United States'' as covering ``relatively permanent, standing or 
continuously flowing bodies of water,'' id. at 739, that are connected 
to traditional navigable waters, id. at 742, as well as wetlands with a 
``continuous surface connection'' to such waterbodies, id. (Scalia, J., 
plurality opinion). The Rapanos plurality noted that its reference to 
``relatively permanent'' waters did ``not necessarily exclude streams, 
rivers, or lakes that might dry up in extraordinary circumstances, such 
as drought,'' or ``seasonal rivers, which contain continuous flow 
during some months of the year but no flow during dry months.'' Id. at 
732 n.5 (emphasis in original).
    Justice Kennedy's concurring opinion took a different approach, 
concluding that ``to constitute `` `navigable waters' '' under the Act, 
a water or wetland must possess a `significant nexus' to waters that 
are or were navigable in fact or that could reasonably be so made.'' 
Id. at 759 (citing SWANCC, 531 U.S. at 167, 172); see also id. at 774 
(``As Riverside Bayview recognizes, the Corps' adjacency standard is 
reasonable in some of its applications. Indeed, the Corps' view draws 
support from the structure of the Act.''). He concluded that wetlands 
possess the requisite significant nexus if the wetlands ``either alone 
or in combination with similarly situated [wet]lands in the region, 
significantly affect the chemical, physical, and biological integrity 
of other covered waters more readily understood as `navigable.' '' Id. 
at 780. Justice Kennedy's opinion noted that to be jurisdictional, such 
a relationship with traditional navigable waters must be more than 
``speculative or insubstantial.'' Id.
    The four dissenting Justices in Rapanos, who would have affirmed 
the Court of Appeals' application of the agencies' regulation to find 
jurisdiction over the waters at issue, also concluded that the term 
``waters of the United States'' encompasses, inter alia, all 
tributaries and wetlands that satisfy ``either the plurality's or 
Justice Kennedy's test'' and that in ``future cases the United States 
may elect to prove jurisdiction under either test.'' Id. at 810 & n.14 
(Stevens, J., dissenting). The four dissenting Justices stated: ``The 
Army Corps has determined that wetlands adjacent to tributaries of 
traditionally navigable waters preserve the quality of our Nation's 
waters by, among other things, providing habitat for aquatic animals, 
keeping excessive sediment and toxic pollutants out of adjacent waters, 
and reducing downstream flooding by absorbing water at times of high 
flow. The Corps' resulting decision to treat these wetlands as 
encompassed within the term `waters of the United States' is a 
quintessential example of the Executive's reasonable interpretation of 
a statutory provision.'' Id. at 788 (citation omitted).
    In addition to joining the plurality opinion, Chief Justice Roberts 
issued his own concurring opinion noting that the agencies ``are 
afforded generous leeway by the courts in interpreting the statute they 
are entrusted to administer,'' and the agencies thus have ``plenty of 
room to operate in developing some notion of an outer bound to the 
reach of their authority'' under the Clean Water Act. Id. at 758 
(emphasis in original). The Chief Justice observed that the Court's 
division over the proper standard ``could have been avoided'' had the 
agencies conducted rulemaking more clearly defining ``its authority to 
regulate wetlands.'' Id.

[[Page 3014]]

4. Post-Rapanos Appellate Court Decisions
    The earliest post-Rapanos decisions by the United States Courts of 
Appeals focused on which standard to apply in interpreting the scope of 
``waters of the United States''--the plurality's or Justice Kennedy's. 
Chief Justice Roberts anticipated this question and cited Marks v. 
United States, 430 U.S. 188 (1977) in his concurring opinion to Rapanos 
as applicable precedent. Marks v. United States provides that ``[w]hen 
a fragmented Court decides a case and no single rationale explaining 
the result enjoys the assent of five Justices, `the holding of the 
Court may be viewed as the position taken by those Members who 
concurred in the judgments on the narrowest grounds.' '' Marks, 430 
U.S. at 193 (quoting Gregg v. Georgia, 428 U.S. 153, 169 n.15 (1976)). 
The dissenting Justices in Rapanos also spoke to future application of 
the divided decision. While Justice Stevens stated that he assumed 
Justice Kennedy's significant nexus standard would apply in most 
instances, the dissenting Justices noted that they would find the Clean 
Water Act extended to waters meeting either the relatively permanent 
standard articulated by Justice Scalia or the significant nexus 
standard described by Justice Kennedy. Rapanos, 547 U.S. at 810 & n.14 
(Stevens, J., dissenting).
    Since Rapanos, every Court of Appeals to have considered the 
question has determined that the government may exercise Clean Water 
Act jurisdiction over at least those waters that satisfy the 
significant nexus standard set forth in Justice Kennedy's concurrence. 
None has held that the plurality's relatively permanent standard is the 
sole basis that may be used to establish jurisdiction. Precon Dev. 
Corp. v. U.S. Army Corps of Eng'rs, 633 F.3d 278 (4th Cir. 2011); see 
also United States v. Donovan, 661 F.3d 174 (3d Cir. 2011); United 
States v. Bailey, 571 F.3d 791 (8th Cir. 2009); United States v. 
Cundiff, 555 F.3d 200 (6th Cir. 2009); United States v. Lucas, 516 F.3d 
316 (5th Cir. 2008); N. Cal. River Watch v. City of Healdsburg, 496 
F.3d 993 (9th Cir. 2007) (superseding the original opinion published at 
457 F.3d 1023 (9th Cir. 2006)); United States v. Johnson, 467 F.3d 56 
(1st Cir. 2006); United States v. Gerke Excavating, Inc., 464 F.3d 723 
(7th Cir. 2006). Some Courts of Appeals have held that the government 
may establish jurisdiction under either standard. See, e.g., United 
States v. Johnson, 467 F.3d 56, 62-64 (1st Cir. 2006); United States v. 
Bailey, 571 F.3d 791, 799 (8th Cir. 2009). The Eleventh Circuit has 
held that only Justice Kennedy's significant nexus standard applies. 
United States v. Robison, 505 F.3d 1208 (11th Cir. 2007).
5. Post-Rapanos Implementation of the 1986 Regulations
    For nearly a decade after Rapanos, the agencies did not revise 
their regulations but instead determined jurisdiction under the 1986 
regulations consistent with the two standards established in Rapanos--
the plurality's relatively permanent standard and Justice Kennedy's 
significant nexus standard--informed by guidance issued jointly by the 
agencies. See U.S. EPA & U.S. Army Corps of Engineers, Clean Water Act 
Jurisdiction Following the U.S. Supreme Court's Decision in Rapanos v. 
United States & Carabell v. United States (June 5, 2007), superseded 
December 2, 2008 (the ``Rapanos Guidance'').
    In the Rapanos Guidance,\32\ the agencies concluded that Clean 
Water Act jurisdiction exists if a water meets either the relatively 
permanent standard or the significant nexus standard. The agencies' 
assertion of jurisdiction over traditional navigable waters and their 
adjacent wetlands remained unchanged by Rapanos. Under the relatively 
permanent standard, the guidance stated that the agencies would assert 
jurisdiction over: non-navigable tributaries of traditional navigable 
waters that typically flow year-round or have continuous flow at least 
seasonally; and wetlands that directly abut such tributaries. Rapanos 
Guidance at 4-7. The guidance stated that the agencies would determine 
jurisdiction under the significant nexus standard for the following 
waters: non-navigable tributaries that are not relatively permanent; 
wetlands adjacent to non-navigable tributaries that are not relatively 
permanent; and wetlands adjacent to but not directly abutting a 
relatively permanent non-navigable tributary. Id. at 8-12. Under the 
guidance, the agencies generally did not assert jurisdiction over 
swales or erosional features (e.g., gullies and small washes 
characterized by low volume or infrequent or short duration flow) or 
ditches (including roadside ditches) excavated wholly in and draining 
only uplands and that did not carry a relatively permanent flow of 
water. Id. at 11-12.
---------------------------------------------------------------------------

    \32\ The agencies note that the guidance ``does not impose 
legally binding requirements on EPA, the Corps, or the regulated 
community, and may not apply to a particular situation depending on 
the circumstances.'' Rapanos Guidance at 4 n.17.
---------------------------------------------------------------------------

B. The Agencies' Post-Rapanos Rules

    Since 2015, EPA and the Army have finalized three rules revising 
the definition of ``waters of the United States.''
1. The 2015 Clean Water Rule
    On June 29, 2015, EPA and the Army published the ``Clean Water 
Rule: Definition of `Waters of the United States,''' 80 FR 37054 (June 
29, 2015) (the ``2015 Clean Water Rule''). The 2015 Clean Water Rule's 
definition of ``waters of the United States'' established three 
categories: (A) waters that are categorically ``jurisdictional by 
rule'' (without the need for additional analysis); (B) waters that are 
subject to case-specific analysis to determine whether they are 
jurisdictional; and (C) waters that are categorically excluded from 
jurisdiction. Id. at 37054. Waters considered ``jurisdictional by 
rule'' included: (1) traditional navigable waters; (2) interstate 
waters, including interstate wetlands; (3) the territorial seas; (4) 
impoundments of waters otherwise identified as jurisdictional; (5) 
tributaries of the first three categories of ``jurisdictional by rule'' 
waters; and (6) waters adjacent to a water identified in the first five 
categories of ``jurisdictional by rule'' waters, including ``wetlands, 
ponds, lakes, oxbows, impoundments, and similar waters.'' Finally, all 
exclusions from the definition of ``waters of the United States'' in 
the pre-2015 regulations were retained, and several exclusions 
reflecting agency practice or based on public comment were added to the 
regulation for the first time. The rule excluded the following (unless 
they were traditional navigable waters, the territorial seas, or 
interstate waters): certain ditches; artificially irrigated areas that 
would revert to dry land should application of water to that area 
cease; artificial, constructed lakes and ponds created in dry land such 
as farm and stock watering ponds, irrigation ponds, settling basins, 
fields flooded for rice growing, log cleaning ponds, or cooling ponds; 
artificial reflecting pools or swimming pools created in dry land; 
small ornamental waters created in dry land; water-filled depressions 
created in dry land incidental to mining or construction activity, 
including pits excavated for obtaining fill, sand, or gravel that fill 
with water; erosional features, including gullies, rills, and other 
ephemeral features that do not meet the definition of tributary, non-
wetland swales, and lawfully constructed grassed waterways; puddles; 
groundwater, including groundwater drained through subsurface drainage 
systems; stormwater control features constructed to convey, treat, or 
store stormwater that are created in dry land; and wastewater

[[Page 3015]]

recycling structures constructed in dry land.
2. The 2019 Repeal Rule
    On February 28, 2017, Executive Order 13778 ``Restoring the Rule of 
Law, Federalism, and Economic Growth by Reviewing the `Waters of the 
United States' Rule,'' directed EPA and the Army to review the 2015 
Clean Water Rule for consistency with the policy outlined in section 1 
of the order and to issue a proposed rule rescinding or revising the 
2015 Clean Water Rule as appropriate and consistent with law. 82 FR 
12497 (March 3, 2017). The Executive Order also directed the agencies 
to ``consider interpreting the term `navigable waters' . . . in a 
manner consistent with'' Justice Scalia's opinion in Rapanos. Id.
    Consistent with this directive, after notice and comment 
rulemaking, on October 22, 2019, the agencies published a final rule 
repealing the 2015 Clean Water Rule and recodifying the 1986 
regulations without any changes to the regulatory text. 84 FR 56626 
(October 22, 2019). The final rule provided that the agencies would 
implement the definition ``consistent with Supreme Court decisions and 
longstanding practice, as informed by applicable agency guidance 
documents, training, and experience''; i.e., consistent with the pre-
2015 regulatory regime. Id. at 56626.
3. The 2020 Navigable Waters Protection Rule
    Three months later, on January 23, 2020, the agencies signed 
another final rule--the ``Navigable Waters Protection Rule: Definition 
of `Waters of the United States''' (``2020 NWPR'')--that for the first 
time defined ``waters of the United States'' based primarily on Justice 
Scalia's plurality test from Rapanos. The 2020 NWPR was published on 
April 21, 2020, and went into effect on June 22, 2020.\33\ 85 FR 22250 
(April 21, 2020). The 2020 NWPR interpreted the term ``the waters'' 
within ``the waters of the United States'' to ``encompass relatively 
permanent flowing and standing waterbodies that are traditional 
navigable waters in their own right or that have a specific surface 
water connection to traditional navigable waters, as well as wetlands 
that abut or are otherwise inseparably bound up with such relatively 
permanent waters.'' Id. at 22273. Specifically, the rule established 
four categories of jurisdictional waters: (1) the territorial seas and 
traditional navigable waters; (2) tributaries of such waters; (3) 
certain lakes, ponds, and impoundments of jurisdictional waters; and 
(4) wetlands adjacent to other jurisdictional waters (other than 
jurisdictional wetlands). Id.
---------------------------------------------------------------------------

    \33\ The 2020 NWPR went into effect on June 22, 2020, in all 
jurisdictions except Colorado, where the rule was subject to a 
preliminary injunction issued by the U.S. District Court for the 
District of Colorado. Colorado v. EPA, 445 F. Supp. 3d 1295 (D. 
Colo. 2020). After the Tenth Circuit reversed the Colorado district 
court's order on appeal, the 2020 NWPR went into effect in Colorado 
on April 26, 2021. Colorado v. EPA, 989 F.3d 874 (6th Cir. 2021); 
Colorado v. EPA, No. 20-1238, ECF No. 010110512604 (Doc. 10825032) 
(10th Cir. Apr. 26, 2021).
---------------------------------------------------------------------------

    The 2020 NWPR further defined the scope of each of these four 
categories. The territorial seas and traditional navigable waters were 
defined consistent with the agencies' longstanding interpretations of 
those terms. A ``tributary'' was defined as a river, stream, or similar 
naturally occurring surface water channel that contributes surface 
water flow to the territorial seas or traditional navigable water in a 
typical year either directly or indirectly through other tributaries, 
jurisdictional lakes, ponds, or impoundments, or adjacent wetlands. A 
tributary was required to be perennial or intermittent in a typical 
year. The term ``tributary'' included a ditch that either relocates a 
tributary, is constructed in a tributary, or is constructed in an 
adjacent wetland as long as the ditch is perennial or intermittent and 
contributes surface water flow to a traditional navigable water or the 
territorial seas in a typical year. Id. at 22251. The definition did 
not include ephemeral features, which were defined as surface waters 
that flow only in direct response to precipitation, including ephemeral 
streams, swales, gullies, rills, and pools. Id.
    The 2020 NWPR defined ``lakes and ponds, and impoundments of 
jurisdictional waters'' as ``standing bodies of open water that 
contribute surface water flow in a typical year to a territorial sea or 
traditional navigable water either directly or through a tributary, 
another jurisdictional lake, pond, or impoundment, or an adjacent 
wetland.'' Id. A lake, pond, or impoundment of a jurisdictional water 
was jurisdictional under the 2020 NWPR if it contributed surface water 
flow to a downstream jurisdictional water in a typical year through 
certain artificial or natural features. A lake, pond, or impoundment of 
a jurisdictional water inundated by flooding from a jurisdictional 
water in a typical year was also jurisdictional. Id.
    As for wetlands, the 2020 NWPR interpreted ``adjacent wetlands'' to 
be those wetlands that abut jurisdictional waters and those non-
abutting wetlands that are (1) ``inundated by flooding'' from a 
jurisdictional water in a typical year, (2) physically separated from a 
jurisdictional water only by certain natural features (e.g., a berm, 
bank, or dune), or (3) physically separated from a jurisdictional water 
by an artificial structure that ``allows for a direct hydrologic 
surface connection'' between the wetland and the jurisdictional water 
in a typical year. Id. at 22251. Wetlands that do not have these types 
of connections to other waters were not jurisdictional.
    The 2020 NWPR expressly provided that waters that do not fall into 
one of these jurisdictional categories were not considered ``waters of 
the United States.'' Id. For the first time, interstate waters were not 
included in the definition of ``waters of the United States.'' The rule 
also excluded groundwater, including groundwater drained through 
subsurface drainage systems; ephemeral features, including ephemeral 
streams, swales, gullies, rills, and pools; diffuse stormwater run-off 
and directional sheet flow over upland; ditches that are not 
traditional navigable waters, the territorial seas, or tributaries as 
defined in the rule; and those portions of ditches constructed in 
adjacent wetlands as defined in the rule that do not satisfy the 
conditions of an adjacent wetland under the rule; prior converted 
cropland; artificially irrigated areas, including fields flooded for 
agricultural production, that would revert to upland should application 
of irrigation water to that area cease; artificial lakes and ponds, 
including water storage reservoirs and farm, irrigation, stock 
watering, and log cleaning ponds, constructed or excavated in upland or 
in non-jurisdictional waters, so long as those artificial lakes and 
ponds are not impoundments of jurisdictional waters that meet the 
rule's definition of lakes and ponds, and impoundments of 
jurisdictional waters; water-filled depressions constructed or 
excavated in upland or in non-jurisdictional waters incidental to 
mining or construction activity; pits excavated in upland or in non-
jurisdictional waters for the purpose of obtaining fill, sand, or 
gravel; stormwater control features constructed or excavated in upland 
or in non-jurisdictional waters to convey, treat, infiltrate, or store 
stormwater runoff; groundwater recharge, water reuse, and wastewater 
recycling structures, including detention, retention, and infiltration 
basins and ponds, constructed or excavated in upland or in non-
jurisdictional waters; and waste treatment systems. While many of these 
exclusions were based on the exclusions

[[Page 3016]]

in the 2015 Clean Water Rule, new exclusions were added and some were 
substantially broadened in a number of ways. For example, for the first 
time, all ephemeral streams were excluded. Moreover, waters within the 
2020 NWPR's jurisdictional categories, including traditional navigable 
waters and the territorial seas, were not ``waters of the United 
States'' if they also fit within the 2020 NWPR's exclusions. See id. at 
22325 (``If the water meets any of the[ ] exclusions, the water is 
excluded even if the water satisfies one or more conditions to be a 
[jurisdictional] water.'').\34\ In addition, the rule expanded the 
longstanding exclusion for prior converted cropland. Generally 
speaking, the 2020 NWPR's approach to prior converted cropland 
substantially reduced the likelihood that prior converted cropland 
would ever lose its excluded status. The 2020 NWPR definition extended 
prior converted cropland status beyond those areas the U.S. Department 
of Agriculture (USDA) defines as prior converted cropland for purposes 
of the Food Security Act.
---------------------------------------------------------------------------

    \34\ The 2020 NWPR's exclusion for ditches, however, explicitly 
did not encompass ditches that are traditional navigable waters or 
jurisdictional tributaries. 33 CFR 328.3(b)(5) (2022).
---------------------------------------------------------------------------

4. Legal Challenges to the Rules
    The agencies' rulemakings to revise the definition of ``waters of 
the United States'' have been subject to a series of legal 
challenges.\35\
---------------------------------------------------------------------------

    \35\ The agencies note that a Clean Water Act case currently 
pending before the Supreme Court is not a direct challenge to any of 
the rules defining ``waters of the United States,'' but instead 
presents the question of the Act's jurisdictional standard for 
adjacent wetlands in the context of a challenge to an EPA 
administrative compliance order for the unauthorized discharge of a 
pollutant into ``waters of the United States.'' Sackett v. EPA, No. 
21-454. Petitioners--who operated a commercial construction and 
excavation business--dumped approximately 1,700 cubic yards of 
gravel and sand to fill wetlands adjacent to ``waters of the United 
States,'' and EPA issued an administrative order in light of the 
unauthorized discharge. The district court and the Court of Appeals 
determined that, under Ninth Circuit precedent, the Clean Water Act 
covers at least those adjacent wetlands that satisfy the significant 
nexus standard. The lower courts held that the administrative record 
supports EPA's conclusion that the wetlands on petitioners' property 
are adjacent to a jurisdictional tributary and that, together with 
other similarly situated adjacent wetlands, the adjacent wetlands 
have a significant nexus to Priest Lake, a traditional navigable 
water.
---------------------------------------------------------------------------

    Multiple parties sought judicial review of the 2015 Clean Water 
Rule in various district and circuit courts. On January 22, 2018, the 
Supreme Court, in a unanimous opinion, held that rules defining the 
scope of ``waters of the United States'' are subject to direct review 
in the district courts. Nat'l Ass'n of Mfrs. v. Dep't of Def., 138 S. 
Ct. 617 (2018). Several of those district court cases remain pending in 
district court or on appeal.\36\ While the 2015 Clean Water Rule went 
into effect in some parts of the country in August 2015, it was never 
implemented nationwide due to multiple injunctions and later 
rulemakings. The day before the 2015 Clean Water Rule's August 28, 2015 
effective date, the U.S. District Court for the District of North 
Dakota preliminarily enjoined the rule in the 13 States challenging the 
rule in that court at the time. North Dakota v. EPA, 127 F. Supp. 3d 
1047 (D.N.D. 2015); Order, North Dakota v. EPA, No. 3:15-cv-59, Dkt. 
No. 79 (D.N.D. Sept. 4, 2015) (limiting scope of preliminary injunction 
to the parties before the court). Shortly thereafter, on October 9, 
2015, the Sixth Circuit issued an order staying the 2015 Clean Water 
Rule nationwide and directing the agencies to resume implementing the 
``familiar, if imperfect'' pre-2015 regulatory regime. In re EPA & 
Dep't of Def. Final Rule, 803 F.3d 804, 806, 808 (6th Cir. 2015). In 
2018, two other district courts issued geographically limited 
preliminary injunctions against the 2015 Clean Water Rule. Georgia v. 
Pruitt, 326 F. Supp. 3d 1356 (S.D. Ga. June 6, 2018) (barring 
implementation of the 2015 Clean Water Rule in 11 States); Texas v. 
EPA, No. 3:15-cv-162, 2018 WL 4518230 (S.D. Tex. Sept. 12, 2018) (same 
as to three States). In 2019, prior to issuance of the 2019 Repeal 
Rule, two courts remanded the 2015 Clean Water Rule to the agencies, 
but neither court vacated the rule. See Texas v. EPA, 389 F. Supp. 3d 
497 (S.D. Tex. 2019); Georgia v. Wheeler, 418 F. Supp. 3d 1336 (S.D. 
Ga. 2019). As such, the 2015 Clean Water Rule remained in effect in 
some parts of the country until the effective date of the 2019 Repeal 
Rule.\37\
---------------------------------------------------------------------------

    \36\ See, e.g., North Dakota v. EPA, No. 15-00059 (D.N.D.); Ohio 
v. EPA, No. 15-02467 (S.D. Ohio) (dismissed as moot), No. 22-3292 
(6th Cir.) (appeal stayed); Southeastern Legal Found. v. EPA, No. 
15-02488 (N.D. Ga.).
    \37\ In February 2018, the agencies issued a rule that added an 
applicability date of February 6, 2020, to the 2015 Clean Water 
Rule. 83 FR 5200 (February 6, 2018) (``Applicability Date Rule''). 
The Applicability Date Rule was challenged in several district court 
actions, and on August 16, 2018, the rule was vacated and enjoined 
nationwide. See South Carolina Coastal Conservation League v. 
Pruitt, 318 F. Supp. 3d 959 (D.S.C. 2018); see also Order, Puget 
Soundkeeper All. v. Wheeler, No. 15-01342 (W.D. Wash. Nov. 26, 2018) 
(vacating the Applicability Date Rule nationwide).
---------------------------------------------------------------------------

    The 2019 Repeal Rule went into effect on December 23, 2019, and 
though it has been the subject of legal challenges, no court has issued 
an adverse ruling with respect to it. The 2019 Repeal Rule was thus in 
effect until the effective date of the 2020 NWPR.
    Multiple parties subsequently sought judicial review of the 2020 
NWPR, which went into effect on June 22, 2020, in all jurisdictions 
except Colorado, where the rule was subject to a preliminary injunction 
issued by the U.S. District Court for the District of Colorado. 
Colorado v. EPA, 445 F. Supp. 3d 1295 (D. Colo. 2020). The Tenth 
Circuit later reversed the Colorado district court's order on appeal; 
as a result, the 2020 NWPR went into effect in Colorado on April 26, 
2021. Colorado v. EPA, 989 F.3d 874 (6th Cir. 2021); Colorado v. EPA, 
No. 20-1238, ECF No. 010110512604 (Doc. 10825032) (10th Cir. Apr. 26, 
2021).
    On August 30, 2021, the U.S. District Court for the District of 
Arizona remanded the 2020 NWPR and vacated the rule. Pascua Yaqui Tribe 
v. EPA, 557 F. Supp. 3d 949 (D. Ariz. 2021). The court found that 
``[t]he seriousness of the Agencies' errors in enacting the NWPR, the 
likelihood that the Agencies will alter the NWPR's definition of 
`waters of the United States,' and the possibility of serious 
environmental harm if the NWPR remains in place upon remand, all weigh 
in favor of remand with vacatur.'' Id. at 956. On September 27, 2021, 
the U.S. District Court for the District of New Mexico also issued an 
order vacating and remanding the 2020 NWPR. Navajo Nation v. Regan, 563 
F. Supp. 3d 1164 (D.N.M. 2021). In vacating the rule, the court agreed 
with the reasoning of the Pascua Yaqui court that the 2020 NWPR suffers 
from ``fundamental, substantive flaws that cannot be cured without 
revising or replacing the NWPR's definition of ``waters of the United 
States.''' Id. at 1168. In six additional cases, courts remanded the 
2020 NWPR without vacatur or without addressing vacatur.\38\
---------------------------------------------------------------------------

    \38\ Order, Pueblo of Laguna v. Regan, No. 1:21-cv-277, Dkt. No. 
40 (D.N.M. Sept. 21, 2021) (declining to reach issue of vacatur in 
light of the Pascua decision); Order, California v. Wheeler, No. 
3:20-cv-3005, Dkt. No. 271 (N.D. Cal. Sept. 16, 2021) (same); Order, 
Waterkeeper All. v. Regan, No. 3:18-cv-3521, Dkt. No. 125 (N.D. Cal. 
Sept. 16, 2021) (same); Order, Conservation Law Found. v. EPA, No. 
1:20-cv-10820, Dkt. No. 122 (D. Mass. Sept. 1, 2021) (same); Order, 
S.C. Coastal Conservation League v. Regan, No. 2:20-cv-1687, Dkt. 
No. 147 (D.S.C. July 15, 2021) (remanding without vacating); Order, 
Murray v. Wheeler, No. 1:19-cv-1498, Dkt. No. 46 (N.D.N.Y. Sept. 7, 
2021) (same).
---------------------------------------------------------------------------

    At this time, 14 cases challenging the 2015 Clean Water Rule, 2019 
Repeal Rule, and/or the 2020 NWPR remain.\39\

[[Page 3017]]

All of these cases are administratively closed, inactive, or being held 
in abeyance as of the date this final rule was signed. See ``History of 
the Effects of Litigation over Recent Definitions of `Waters of the 
United States''' in the docket for this rule for more information on 
how litigation has impacted the status of the definition of ``waters of 
the United States'' in effect at different times across the country.
---------------------------------------------------------------------------

    \39\ Pascua Yaqui Tribe v. EPA, No. 4:20-cv-266 (D. Ariz.); 
Colorado v. EPA, No. 1:20-cv-1461 (D. Colo.); Am. Exploration & 
Mining Ass'n v. EPA, No. 1:16-cv-1279 (D.D.C.); Envtl. Integrity 
Project v. Regan, No. 1:20-cv-1734 (D.D.C.); Se. Stormwater Ass'n v. 
EPA, No. 4:15-cv-579 (N.D. Fla.); Se. Legal Found. v. EPA, No. 1:15-
cv-2488 (N.D. Ga.); Chesapeake Bay Found. v. Regan, Nos. 1:20-cv-
1063 & 1:20-cv-1064 (D. Md.); Navajo Nation v. Regan, No. 2:20-cv-
602 (D.N.M.); N.M. Cattle Growers' Ass'n v. EPA, No. 1:19-cv-988 
(D.N.M.); North Dakota v. EPA, No. 3:15-cv-59 (D.N.D.); Ohio v. EPA, 
No. 2:15-cv-2467 (S.D. Ohio) (dismissed as moot), No. 22-3292 (6th 
Cir.) (appeal stayed); Or. Cattlemen's Ass'n v. EPA, No. 3:19-cv-564 
(D. Or.); Puget Soundkeeper All. v. EPA, No. 2:20-cv-950 (W.D. 
Wash.); Wash. Cattlemen's Ass'n v. EPA, No. 2:19-cv-569 (W.D. 
Wash.).
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5. 2021 Executive Order and Review of the Navigable Waters Protection 
Rule
    On January 20, 2021, President Biden signed Executive Order 13990, 
entitled ``Executive Order on Protecting Public Health and the 
Environment and Restoring Science to Tackle the Climate Crisis.'' It 
provides that ``[i]t is, therefore, the policy of my Administration to 
listen to the science; to improve public health and protect our 
environment; to ensure access to clean air and water; to limit exposure 
to dangerous chemicals and pesticides; to hold polluters accountable, 
including those who disproportionately harm communities of color and 
low-income communities; to reduce greenhouse gas emissions; to bolster 
resilience to the impacts of climate change; to restore and expand our 
national treasures and monuments; and to prioritize both environmental 
justice and the creation of the well-paying union jobs necessary to 
deliver on these goals.'' 86 FR 7037, section 1 (published January 25, 
2021, signed January 20, 2021). The order ``directs all executive 
departments and agencies (agencies) to immediately review and, as 
appropriate and consistent with applicable law, take action to address 
the promulgation of Federal regulations and other actions during the 
last 4 years that conflict with these important national objectives, 
and to immediately commence work to confront the climate crisis.'' Id. 
The order specified that ``[f]or any such actions identified by the 
agencies, the heads of agencies shall, as appropriate and consistent 
with applicable law, consider suspending, revising, or rescinding the 
agency actions.'' Id. at section 2(a). The order also revoked Executive 
Order 13778 of February 28, 2017 (Restoring the Rule of Law, 
Federalism, and Economic Growth by Reviewing the ``Waters of the United 
States'' Rule), which had initiated development of the 2020 NWPR. Id. 
at section 7(a).
    In conformance with Executive Order 13990, the agencies reviewed 
the 2020 NWPR to determine its alignment with three principles laid out 
in the Executive Order: science, climate change, and environmental 
justice.
    Science: Science plays a critical role in understanding how to 
protect the integrity of our nation's waters. As discussed in detail 
below, see section IV.B.3 of this preamble, the 2020 NWPR did not 
properly consider the extensive scientific evidence demonstrating the 
interconnectedness of waters and their downstream effects, thereby 
undermining Congress's objective to restore and maintain the chemical, 
physical, and biological integrity of the nation's waters. The 2020 
NWPR's definition of ``waters of the United States'' does not 
adequately consider the way pollution moves through waters or the way 
filling in a wetland affects downstream water resources.
    Climate: Science has established that human and natural systems 
have been and continue to be extensively impacted by climate change. 
Climate change can have a variety of impacts on water resources in 
particular. See section II.C of the Technical Support Document. For 
instance, a warming climate is already increasing precipitation in many 
areas (e.g., the Northeast and Midwest), while decreasing precipitation 
in other areas (e.g., the Southwest). Other areas are experiencing more 
extreme cycles of flood and drought (e.g., the Northern Great Plains). 
Climate change can increase the intensity of precipitation events. 
Runoff from more intense storms can impair water quality as pollutants 
deposited on land wash into waterbodies. Changes in streamflow, 
snowmelt timing, snowpack accumulation, and the size and frequency of 
heavy precipitation events can also cause river floods to become larger 
or more frequent than they used to be in some places. In addition, 
climate change affects streamflow characteristics, such as the 
magnitude and timing of flows, in part due to changes in snowpack 
magnitude and seasonality. Many historically dry areas are experiencing 
less precipitation and an increased risk of drought associated with 
more frequent and intense heatwaves, which cause streams and wetlands 
to become drier, negatively affecting water supplies and water quality. 
Heatwaves, associated drought, and the loss of surface and soil 
moisture associated with longer dry seasons, lower streamflow, and 
lower groundwater levels also affect the frequency, size, and duration 
of wildfires, which alter water quality and impact wetlands and their 
functions. A changing climate can also result in higher and more 
variable temperatures in streams, killing fish and harming other 
aquatic species that can live only in colder water. Finally, rising sea 
levels associated with climate change are inundating low-lying streams 
and wetlands and further contributing to coastal flooding and erosion.
    Although water resources are vulnerable to climate change, when 
their interconnectedness and extent are maintained, streams and 
wetlands perform a variety of functions that contribute to climate 
resiliency by mitigating negative effects on traditional navigable 
waters, the territorial seas, and interstate waters. For instance, 
wetlands inside and outside of floodplains store large volumes of 
floodwaters, thereby reducing flood peaks and protecting downstream 
watersheds. As natural filters, wetlands help purify and protect the 
quality of other waterbodies, including drinking water supplies--a 
function which is more important than ever as intense precipitation 
events spurred on by a changing climate mobilize sediment, nutrients, 
and other pollutants. Coastal wetlands help buffer storm surges, which 
may increase in frequency or severity with sea-level rise and the 
increasing size and intensity of coastal storms. Additionally, small 
streams are particularly effective at retaining and attenuating 
floodwaters. Biological communities and geomorphic processes in small 
streams and wetlands break down leaves and other organic matter, 
sequestering a portion of that carbon that could otherwise be released 
into the atmosphere and continue to negatively affect water resources.
    The 2020 NWPR did not appropriately acknowledge or take account of 
the effects of a changing climate on the chemical, physical, and 
biological integrity of the nation's waters. For example, its rolling 
thirty-year approach to determining a ``typical year'' did not allow 
the agencies flexibility to account for the effects of a rapidly 
changing climate, including upward trending temperatures, increasing 
storm events, and extended droughts (see section IV.B.3.c of this 
preamble). The 2020 NWPR also categorically excluded ephemeral streams 
and their adjacent wetlands from the definition of ``waters of the 
United States.'' These exclusions, if in effect, would 
disproportionately impact the arid West. Aquatic systems comprised 
largely of ephemeral streams are increasingly critical to protecting

[[Page 3018]]

and maintaining the integrity of paragraph (a)(1) waters, for example 
by contributing streamflow and organic matter to those larger waters. 
This is especially true in the Southwestern United States, where 
climate change is expanding the spatial extent of arid conditions and 
increasing the risks of more extreme drought. Some portions of the arid 
West are experiencing altered monsoon seasons that have fewer but more 
intense storms that contribute to so-called ``flashy'' stream hydrology 
(i.e., higher runoff volume, leading to more rapidly rising and falling 
streamflow over shorter periods of time).
    Environmental Justice: While impacts on communities with 
environmental justice concerns are not a basis for determining the 
scope of the definition of ``waters of the United States,'' the 
agencies recognize that the burdens of environmental pollution and 
climate change often fall disproportionately on communities with 
environmental justice concerns (e.g., minority (Indigenous peoples and/
or people of color) and low-income populations, as specified in 
Executive Order 12898). Numerous groups have raised concerns that the 
2020 NWPR had disproportionate impacts on Tribes and Indigenous 
communities.\40\ The 2020 NWPR decreased the scope of Clean Water Act 
jurisdiction across the country, including in geographic regions where 
regulation of waters beyond those covered by the Act is not authorized 
under current Tribal or State law (see section IV.B.3.d of this 
preamble). If the 2020 NWPR were in effect, without regulations 
governing discharges of pollutants into previously jurisdictional 
waters, communities with environmental justice concerns where these 
waters are located could experience increased water pollution and 
impacts from associated increases in health risk.
---------------------------------------------------------------------------

    \40\ See, e.g., Tribal Consultation Comment Letter from 
President Jonathan Nez and Vice President Myron Lizer, Navajo 
Nation, October 4, 2021 (``The Navajo Nation relies greatly on all 
its surface waters, including ephemeral, intermittent, and perennial 
surface waters. The Navajo Nation currently lacks the resources to 
implement CWA permitting and other programs necessary to maintain 
and protect water quality and relies on the Agencies to fill that 
need. Therefore, any new [``waters of the United States''] rule must 
not reduce the scope of the waters that the Agencies can protect, or 
it will have `disproportionately high and adverse human health or 
environmental effects' on the Navajo Nation.''), and Tribal 
Consultation Comment Letter from Clarice Madalena, Interim Director, 
Natural Resources Department, Pueblo of Jemez, October 4, 2021 
(stating that desert ``hydrology and the geographic location of 
Native communities--means that the Navigable Waters Rule had the 
effect of disparately stripping Clean Water Act protections from 
areas with higher Native populations. This means that the Rule 
disproportionately harmed Native American communities. This 
discriminatory impact violates the principles of environmental 
justice'') (citations omitted). See also section IV.B.3.d of this 
preamble and Technical Support Document section II.B.D.
---------------------------------------------------------------------------

    Further, the 2020 NWPR's categorical exclusion of ephemeral streams 
from jurisdiction (and any wetlands adjacent to those streams) 
disproportionately impacted Tribes and communities with environmental 
justice concerns in the arid West. Many Tribes lack the authority and 
resources to regulate waters within their boundaries, and they may also 
be affected by pollution from adjacent jurisdictions.\41\ In addition, 
under the 2020 NWPR, increased water pollution due to the elimination 
of Federal protection over ephemeral streams and their adjacent 
wetlands could lead to health impacts and the reduction of clean water 
needed for traditional agricultural, cultural, and subsistence uses for 
communities with environmental justice concerns.\42\ Therefore, if in 
effect, the 2020 NWPR could disproportionately expose Tribes to 
increased pollution and health risks.
---------------------------------------------------------------------------

    \41\ See supra note 40.
    \42\ See, e.g., comments submitted by Navajo Nation at 3 
(February 7, 2022) (Docket ID No. EPA-HQ-OW-2021-0602-0581), https://www.regulations.gov/comment/EPA-HQ-OW-2021-0602-0581 (``Nor did the 
NWPR consider environmental justice concerns, including that tribes, 
among other environmental justice communities, `may experience 
increased water pollution and impacts from associated increases in 
health risk.' '' (citation omitted)); comments submitted by Amigos 
Bravos et al. at 2 (February 7, 2022) (Docket ID No. EPA-HQ-OW-2021-
0602-0600), https://www.regulations.gov/comment/EPA-HQ-OW-2021-0602-0600 (``Many New Mexican farmers of color depend upon clean water 
flowing from the ephemeral drainages in headwater systems to water 
their crops and livestock. New Mexico acequias (community irrigation 
ditches) help to convey and distribute surface water to tens of 
thousands of New Mexican acequia families and over 100,000 acres of 
irrigable lands, primarily for traditional agricultural and cultural 
uses. New Mexico's surface waters are the lifeblood of numerous 
acequias, sustaining and enriching centuries-old acequias and 
farming and ranching traditions which depend upon clean water. 
Protecting clean water in New Mexico is intricately tied to 
environmental justice.'').
---------------------------------------------------------------------------

    After completing the review and reconsidering the record for the 
2020 NWPR, on June 9, 2021, the agencies announced their intention to 
revise or replace the rule. The factors the agencies found most 
relevant in making this decision were the text, structure, and history 
of the Clean Water Act; relevant Supreme Court case law; the current 
and future harms to the chemical, physical, and biological integrity of 
the nation's waters due to implementation of the 2020 NWPR; concerns 
raised by co-regulators and stakeholders about the 2020 NWPR, including 
implementation-related issues; the principles outlined in the Executive 
Order; and issues raised in ongoing litigation challenging the 2020 
NWPR. EPA and the Army concluded that the 2020 NWPR did not 
appropriately consider the effect of the revised definition of ``waters 
of the United States'' on the integrity of the nation's waters, and 
that it threatened the loss or degradation of waters critical to the 
protection of traditional navigable waters, the territorial seas, and 
interstate waters, among other concerns.

C. Summary of Co-Regulator Engagement and Stakeholder Outreach

    EPA and the Army held a series of stakeholder meetings during the 
agencies' review of the 2020 NWPR, including specific meetings in May 
2021 with industry, environmental organizations, agricultural 
organizations, and State associations. On July 30, 2021, the agencies 
signed a Federal Register document that announced a schedule for 
initial public meetings to hear from interested stakeholders on their 
perspectives on defining ``waters of the United States'' and 
implementing the definition. 86 FR 41911 (August 4, 2021). The agencies 
also announced their intent to accept written pre-proposal 
recommendations from members of the public for a 30-day period from 
August 4, 2021, to September 3, 2021. The agencies received over 32,000 
recommendation letters from the public, which can be found in the pre-
proposal docket (Docket ID No. EPA-HQ-OW-2021-0328). Consistent with 
the August 4, 2021, Federal Register publication, the agencies held six 
public meeting webinars on August 18, August 23, August 25 
(specifically for small entities), August 26, August 31, and September 
2, 2021.
    The agencies also engaged State and local governments over a 60-day 
federalism consultation period during development of the proposed rule, 
beginning with an initial federalism consultation meeting on August 5, 
2021, and concluding on October 4, 2021. A total of thirty-eight 
letters were submitted to the agencies as part of the federalism 
consultation process from State and local government agencies, 
intergovernmental associations, and State-level associations. On 
September 29, October 6, and October 20, 2021, the agencies hosted 
virtual meetings with States focused on implementation of prior 
``waters of the United States'' regulatory regimes. Additional 
information about the federalism consultation can be found in section 
V.E of this preamble and the Summary

[[Page 3019]]

Report of Federalism Consultation, available in the docket for this 
rule.
    The agencies initiated a Tribal consultation and coordination 
process during development of the proposed rule which was conducted 
over a 66-day period from July 30, 2021, until October 4, 2021, 
including two consultation kick-off webinars. The agencies received 
consultation comment letters from 27 Tribes and three Tribal 
organizations and held three leader-to-leader consultation meetings and 
four staff-level meetings with Tribes at their request. On October 7, 
13, 27, and 28, 2021, the agencies hosted virtual dialogues with Tribes 
focused on implementation of prior ``waters of the United States'' 
regulatory regimes. Additional information about Tribal consultation 
and engagement can be found in section V.F of this preamble and the 
Summary of Tribal Consultation and Coordination, which is available in 
the docket for this rule.
    The agencies signed a proposed rule defining ``waters of the United 
States'' on November 18, 2021. On December 7, 2021, the agencies 
published the proposed rulemaking in the Federal Register, 86 FR 69372, 
which initiated a 60-day public comment period that lasted through 
February 7, 2022. EPA and Army held three virtual public hearings on 
January 11, 13, and 18, 2022. The Office of Advocacy of the U.S. Small 
Business Administration hosted EPA and Army staff in January 2022 to 
discuss the proposed rule with small entities at its Small Business 
Environmental Roundtables. The agencies met with small agricultural 
interests and their representatives for a roundtable on January 7, 
2022, and met with other small entities on January 10, 2022. The 
agencies also engaged with State and local governments during the 
public comment period, including through two virtual roundtables on 
January 24 and 27, 2022. The agencies continued to engage with Tribes 
during the public comment period. On January 20, 2022, the agencies 
hosted a Tribal virtual roundtable.
    In developing this rule, the agencies reviewed and considered 
approximately 114,000 comments received on the proposed rulemaking from 
a broad spectrum of interested parties. Commenters provided a wide 
range of feedback on the proposal, including: the legal basis for the 
proposed rule; the agencies' proposed treatment of categories of 
jurisdictional waters and those features that would not be 
jurisdictional; the Economic Analysis and Technical Support Document 
for the proposed rule; and the need for a clear and implementable rule 
that is easy for the public to understand. The agencies discuss 
comments received and their responses in the applicable sections of the 
preamble to this rule. A complete response to comments document is 
available in the docket for this rule (Docket ID No. EPA-HQ-OW-2021-
0602).
    The agencies also engaged with EPA's Science Advisory Board (SAB) 
on several occasions during the development of this rule. The SAB was 
established in 1978 by the Environmental Research, Development, and 
Demonstration Authorization Act (ERDDAA), to provide independent 
scientific and technical advice to the EPA Administrator on the 
technical basis for agency positions and regulations.
    On January 28, 2022, during the public comment period, the agencies 
met with the SAB Work Group for Review of Science Supporting EPA 
Decisions to explain the proposed rule, including its basis, and to 
address the SAB Work Group's initial questions. On February 7, 2022, 
the SAB Work Group signed a memorandum recommending that the Chartered 
SAB should review the adequacy of the science supporting the proposed 
rule. SAB Memorandum: Recommendations of the SAB Work Group for Review 
of Science Supporting EPA Decisions Regarding Two Planned EPA 
Regulatory Actions (February 7, 2022). On March 7, 2022, during the 
public meeting of the Chartered SAB, the Chartered SAB unanimously 
voted to review the scientific and technical basis of the proposed 
rule. The SAB formed a Work Group of its chartered members which issued 
a draft review on May 9, 2022, and the Chartered SAB held public 
meetings on the matter on May 31 and June 2, 2022. The SAB issued their 
final review on July 5, 2022 (EPA-SAB-22-005, hereinafter, ``2022 SAB 
Review''). All materials related to the SAB's review are available in 
the docket for this rule and on the SAB's website.
    The SAB's review of the proposed rule was overall supportive of the 
science underpinning the proposed rule, including the Technical Support 
Document, and the discussion of shallow subsurface flow. The SAB made 
some recommendations on the discussion of climate change. The SAB's 
review was also generally favorable towards the approaches taken in the 
Economic Analysis supporting the proposed rule. The SAB made 
recommendations for improvement of the Economic Analysis, particularly 
regarding the environmental federalism approach and the continued non-
monetization of certain benefits. The SAB indicated that the agencies' 
plans for expanding the environmental justice analysis for this rule 
were appropriate and provided recommendations for improving and 
clarifying the analysis. A memorandum summarizing the agencies' 
interactions with the SAB and the SAB's review of the proposed rule is 
available in the docket for this rule.

IV. Revised Definition of ``Waters of the United States''

A. Basis for This Rule

    In this rule, the agencies are exercising their authority to 
interpret ``waters of the United States'' to mean the waters defined by 
the familiar 1986 regulations, with amendments to reflect the agencies' 
determination of the statutory limits on the scope of the ``waters of 
the United States'' informed by the text of the relevant provisions of 
the Clean Water Act and the statute as a whole, the scientific record, 
relevant Supreme Court precedent, and the agencies' experience and 
technical expertise after more than 45 years of implementing the 
longstanding pre-2015 regulations defining ``waters of the United 
States.'' \43\ The agencies construe the term ``waters of the United 
States'' to mean: (1) traditional navigable waters, the territorial 
seas, and interstate waters (``paragraph (a)(1) waters''); (2) 
impoundments of ``waters of the United States'' (``paragraph (a)(2) 
impoundments''); (3) tributaries to traditional navigable waters, the 
territorial seas, interstate waters, or paragraph (a)(2) impoundments 
when the tributaries meet either the relatively permanent standard or 
the significant nexus standard (``jurisdictional tributaries''); (4) 
wetlands adjacent to paragraph (a)(1) waters; wetlands adjacent to and 
with a continuous surface connection to relatively permanent paragraph 
(a)(2) impoundments or jurisdictional tributaries when the 
jurisdictional tributaries meet the relatively permanent standard; and 
wetlands adjacent to paragraph (a)(2) impoundments or jurisdictional 
tributaries when the wetlands meet the significant nexus standard 
(``jurisdictional adjacent wetlands'');

[[Page 3020]]

and (5) intrastate lakes and ponds, streams, or wetlands not identified 
in paragraphs (a)(1) through (4) that meet either the relatively 
permanent standard or the significant nexus standard (``paragraph 
(a)(5) waters''). This rule also contains, at paragraph (b), the 
longstanding exclusions in the 1986 regulations, as well as additional 
exclusions based on well-established practice, from the definition of 
``waters of the United States'' and, at paragraph (c), definitions for 
terms used in this rule.
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    \43\ For brevity, the agencies may refer to the considerations 
that formed the basis of the agencies' interpretation of ``waters of 
the United States'' in the final rule as ``the law, the science, and 
agency expertise.'' References to the agencies' consideration of 
``the law, the science, and agency expertise'' throughout this 
preamble are intended to encompass the agencies' consideration of 
the text of the relevant provisions of the Clean Water Act and the 
statute as a whole, the scientific record, relevant Supreme Court 
decisions, and the agencies' experience and technical expertise 
implementing the pre-2015 regulatory regime.
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    This rule advances the Clean Water Act's statutory objective to 
``restore and maintain the chemical, physical, and biological integrity 
of the Nation's waters,'' section 101(a), as it is informed by the best 
available science concerning the functions provided by upstream 
tributaries, adjacent wetlands, and paragraph (a)(5) waters to restore 
and maintain the water quality of paragraph (a)(1) waters. In 
developing the rule, the agencies also considered the text of the 
relevant statutory provisions of the Clean Water Act and the statute as 
a whole, relevant Supreme Court case law, and the agencies' experience 
and technical expertise after more than 45 years of implementing the 
1986 regulations defining ``waters of the United States,'' including 
more than a decade of experience implementing those regulations 
consistent with the decisions in Riverside Bayview, SWANCC, and Rapanos 
collectively.
    This construction also reflects consideration of provisions of the 
Clean Water Act referencing the role of the States. Section 101(b) 
provides that ``[i]t is the policy of the Congress to recognize, 
preserve, and protect the primary responsibilities and rights of States 
to prevent, reduce, and eliminate pollution, to plan the development 
and use (including restoration, preservation, and enhancement) of land 
and water resources.'' The provisions in this rule reflect 
consideration of the comprehensive nature and objective of the Clean 
Water Act and also avoid assertions of jurisdiction that raise 
federalism concerns. Determining where to draw the boundaries of 
Federal jurisdiction to ensure that the agencies advance Congress's 
objective while preserving and protecting the responsibilities and 
rights of the States is assigned by Congress to the agencies. This 
rule's relatively permanent and significant nexus limitations 
appropriately draw this boundary by ensuring that where upstream waters 
significantly affect the integrity of the traditional navigable waters, 
the territorial seas, and interstate waters, Clean Water Act programs 
will apply to ensure that those downstream waters have a baseline of 
protection established by Federal law. Where they do not, Tribes and 
States have authority. These limitations are based on the agencies' 
conclusion that the significant nexus standard is consistent with the 
statutory text and legislative history, advances the objective of the 
Clean Water Act, is informed by the scientific record and Supreme Court 
case law, and appropriately considers the policies of the Act, and 
that, while the relatively permanent standard, standing alone, 
identifies only a subset of the ``waters of the United States,'' 
including this standard in the final rule facilitates ease of 
implementation. In addition, this rule reflects consideration of the 
agencies' experience and expertise, as well as updates in 
implementation tools and resources, and its terms are generally 
familiar and implementable.
    For all these reasons, this rule will achieve the agencies' goals 
of effectively and durably protecting the quality of the nation's 
waters. The effectiveness of this rule is based, in part, on the 
familiarity of the regulatory framework to the agencies and 
stakeholders, with an array of readily available tools and resources. 
This rule also is durable because it is founded on the familiar 
framework of the longstanding 1986 regulations, amended to reflect the 
agencies' interpretation of appropriate limitations on the geographic 
scope of the Clean Water Act in light of the law, the science, and 
agency expertise. This rule also reflects the agencies' consideration 
of the extensive public comments. This rule protects the quality of the 
nation's waters by restoring the important protections for 
jurisdictional waters provided by the Clean Water Act, including not 
only protections provided by the Act's permitting programs, but also 
protections provided by programs ranging from water quality standards 
and total maximum daily loads to oil spill prevention, preparedness, 
and response programs, to the Tribal and State water quality 
certification programs.
1. The Agencies Are Exercising the Authority Granted by Congress To 
Define ``Waters of the United States'' Under the Clean Water Act
    The agencies are exercising the authority granted to them by 
Congress in the Clean Water Act to construe the key term ``navigable 
waters,'' which Congress broadly defined to mean ``the waters of the 
United States, including the territorial seas.'' 33 U.S.C. 1362(7) 
(Clean Water Act section 502(7)). As explained herein, the text of the 
statute, including in particular sections 501 and 502(7), and 
congressional intent provide that delegation of authority. And the 
Supreme Court has affirmed the conclusion that the agencies have the 
authority to define the bounds of ``waters of the United States.'' In 
this rule, the agencies are using the traditional tools of statutory 
construction to exercise their delegated authority. Further, the rule 
is founded upon the longstanding 1986 regulations, familiar to Congress 
and the Court, while incorporating important limitations based on the 
text of the statute. Finally, it is well established that agencies have 
inherent authority to reconsider past decisions and to revise, replace, 
or repeal a decision to the extent permitted by law and supported by a 
reasoned explanation.
    Congress's intent to delegate authority to the agencies to construe 
the term ``navigable waters'' and its definition in section 502(7), 
``the waters of the United States, including the territorial seas,'' is 
clear from this text in the Clean Water Act. First, Congress 
established a broad definition of a term foundational to advancing the 
Act's clear objective that requires additional interpretation to 
implement that term by the expert agencies charged with administering 
the statute. Second, Congress explicitly delegated such authority to 
EPA: ``The Administrator is authorized to prescribe such regulations as 
are necessary to carry out his functions under this Act.'' 33 U.S.C. 
1361 (Clean Water Act section 501). Clearly, interpreting this key term 
through regulation is necessary to carry out the functions of the Act.
    Congressional intent affirms this delegation. The breadth of the 
definition of ``navigable waters'' reflects a deliberate choice by 
Congress to both enact a statute with a broad scope of waters protected 
by Federal law and to delegate the authority to interpret the 
specialized term and its definition to the expert agencies. The 
relevant House bill would have defined ``navigable waters'' as the 
``navigable waters of the United States, including the territorial 
seas.'' H.R. Rep. No. 911, 92d Cong., 2d Sess. 356 (1972) (emphasis 
omitted). But the House was concerned that the definition might be 
given an unduly narrow interpretation. The House Report observed: ``One 
term that the Committee was reluctant to define was the term `navigable 
waters.' The reluctance was based on the fear that any interpretation 
would be read narrowly. However, this is not the Committee's intent. 
The Committee fully intends that the term `navigable waters' be given 
the broadest possible constitutional interpretation unencumbered by 
agency determinations which have been made

[[Page 3021]]

or may be made for administrative purposes.'' H.R. Rep. No. 92-911, at 
131 (1972). The Senate Report also expressed disapproval of the narrow 
construction by the Corps of the scope of waters protected under prior 
water protection statutes, stating ``[t]hrough a narrow interpretation 
of the definition of interstate waters the implementation [of the] 1965 
Act was severely limited. Water moves in hydrologic cycles and it is 
essential that discharge of pollutants be controlled at the source.'' 
S. Rep. No. 92-414, at 77 (1971). Thus, in conference the word 
``navigable'' was deleted from that definition, and the conference 
report again urged that the term ``be given the broadest possible 
constitutional interpretation unencumbered by agency determinations 
which have been made or may be made for administrative purposes.'' S. 
Conf. Rep. No. 1236, 92d Cong., 2d Sess. 144 (1972). Congress thus 
intended the agencies to which it granted authority to implement the 
Clean Water Act to interpret the scope of the definition of ``navigable 
waters'' consistent with Congress's intent and objective in enacting 
the Act.
    The Supreme Court has also affirmed the conclusion that it is the 
agencies' role to interpret the term ``waters of the United States.'' 
As the Court explained in Riverside Bayview, Congress delegated a 
``breadth of federal regulatory authority'' and expected the agencies 
to tackle the ``inherent difficulties of defining precise bounds to 
regulable waters.'' 474 U.S. at 134.
    In addition, any ambiguity in Congress's terms in Clean Water Act 
section 502(7) further underscores the role of the agencies in 
interpreting the statutory language. The Riverside Bayview Court 
deferred to and upheld the agencies' interpretation of the Clean Water 
Act to protect wetlands adjacent to navigable-in-fact bodies of water, 
stating ``[a]n agency's construction of a statute it is charged with 
enforcing is entitled to deference if it is reasonable and not in 
conflict with the expressed intent of Congress.'' 474 U.S. at 131 
(citations omitted). All nine Justices in Rapanos again recognized that 
there was ambiguity in the terms of the Clean Water Act. 547 U.S. at 
752, 758, 780, 796, 811-12. In concurring with the Rapanos plurality 
opinion, the Chief Justice explained that, given the ``broad, somewhat 
ambiguous, but nonetheless clearly limiting terms Congress employed in 
the Clean Water Act, the Corps and the EPA would have enjoyed plenty of 
room to operate'' if they had addressed the relevant interpretive 
questions through rulemaking. 547 U.S. at 758 (Roberts, C.J., 
concurring). The Chief Justice emphasized the breadth of the agencies' 
discretion in defining ``waters of the United States'' through 
rulemaking; indeed, the agencies' interpretations under the Clean Water 
Act, Chief Justice Roberts emphasized, are ``afforded generous leeway 
by the courts.'' Id. at 758.
    In exercising their authority to interpret the statute in this 
rule, the agencies are ``employing the traditional tools of statutory 
interpretation,'' American Hospital Association v. Becerra, 142 S. Ct. 
1896, 1906 (2022) (per curiam), beginning with ``the text and structure 
of the statute,'' id. at 1904, as well as ``with reference to the 
statutory context, `structure, history, and purpose,' '' Abramski v. 
United States, 573 U.S. 169, 179 (2014) (citation omitted). As 
discussed further in this section IV.A of the preamble, the agencies 
have used additional tools of statutory construction, including the 
statutory history, the statute as a whole, the objective of the Clean 
Water Act, and the legislative history, which clears up ambiguity, in 
construing the Act. See Bostock v. Clayton County, Georgia, 140 S. Ct. 
1731, 1749 (2020) (discussing use of legislative history by the Supreme 
Court ``when interpreting ambiguous statutory language'' (emphasis in 
original) and noting that ``[l]egislative history, for those who take 
it into account, is meant to clear up ambiguity, not create it'' 
(citing Milner v. Department of Navy, 562 U.S. 562, 574 (2011))).
    The agencies have also properly brought to bear their expertise and 
experience in construing the Clean Water Act. As the Supreme Court 
concluded in Riverside Bayview, ``In view of the breadth of federal 
regulatory authority contemplated by the Act itself and the inherent 
difficulties of defining precise bounds to regulable waters, the Corps' 
ecological judgment about the relationship between waters and their 
adjacent wetlands provides an adequate basis for a legal judgment that 
adjacent wetlands may be defined as waters under the Act.'' 474 U.S. at 
134. In addition, the agencies have more than 45 years of experience 
implementing the longstanding pre-2015 regulations defining ``waters of 
the United States,'' including more than a decade of implementing those 
regulations consistent with the Supreme Court's decisions in Riverside 
Bayview, SWANCC, and Rapanos, and have concluded this rule is also 
consistent with the ``longstanding practice of [the agencies] in 
implementing the relevant statutory authorities.'' Biden v. Missouri, 
142 S. Ct. 647, 652 (2022). Finally, Congress is aware of the agencies' 
longstanding interpretation of ``waters of the United States'' and has 
not acted to limit the agencies' interpretation, but rather has 
incorporated aspects of the agencies' regulatory definition into the 
statute. See section IV.A.2.b of this preamble.
    Further, agencies have inherent authority to reconsider past 
decisions and to revise, replace, or repeal a decision to the extent 
permitted by law and supported by a reasoned explanation. FCC v. Fox 
Television Stations, Inc., 556 U.S. 502, 515 (2009) (``Fox''); Motor 
Vehicle Manufacturers Ass'n of the United States, Inc. v. State Farm 
Mutual Automobile Insurance Co., 463 U.S. 29, 42 (1983) (``State 
Farm''); see also Encino Motorcars, LLC v. Navarro, 136 S. Ct. 2117, 
2125 (2016) (``Agencies are free to change their existing policies as 
long as they provide a reasoned explanation for the change.''). Such a 
decision need not be based upon a change of facts or circumstances. A 
revised rulemaking based ``on a reevaluation of which policy would be 
better in light of the facts'' is ``well within an agency's 
discretion.'' Nat'l Ass'n of Home Builders v. EPA, 682 F.3d 1032, 1038 
& 1043 (D.C. Cir. 2012) (citing Fox, 556 U.S. at 514-15). As discussed 
further in section IV.B.3 of this preamble, the agencies have reviewed 
the 2020 NWPR and determined that the rule should be replaced. This 
rule properly considers the objective of the Clean Water Act, is 
consistent with the text and structure of the Act, informed by relevant 
Supreme Court precedent, and reflects the record before the agencies, 
including consideration of the best available science, as well as the 
agencies' expertise and experience implementing the pre-2015 regulatory 
regime.
    To be clear, in this rule the agencies are exercising the authority 
granted to them by Congress to construe and implement the Clean Water 
Act and to interpret an ambiguous term and its statutory definition. 
Therefore, while the agencies' interpretation of the statute is 
informed by Supreme Court decisions, including Rapanos, it is not an 
interpretation of the multiple opinions in Rapanos, nor is it based on 
an application of the Supreme Court's principles to derive a governing 
rule of law from a decision of the Court in a case such as Rapanos 
where ``no opinion commands a majority.'' Rapanos, 547 U.S. at 758 
(Roberts, C.J., concurring) (citing Marks v. United States, 430 U.S. 
188, 193 (1977) (``Marks'')). Rather, this rule codifies the agencies' 
interpretation of ``navigable waters'' informed by the text of the 
relevant provisions of the Clean Water

[[Page 3022]]

Act and the statute as a whole, as well as the scientific record, 
relevant Supreme Court case law, input from public comment, and the 
agencies' experience and technical expertise after more than 45 years 
of implementing the longstanding pre-2015 regulations defining ``waters 
of the United States,'' including more than a decade of implementing 
the regulations after Rapanos. Based on these considerations, the 
agencies have concluded that the significant nexus standard in this 
rule is the best interpretation of section 502(7) of the Clean Water 
Act.
2. This Rule Advances the Objective of the Clean Water Act
    This rule is grounded in the Clean Water Act's objective ``to 
restore and maintain the chemical, physical, and biological integrity 
of the Nation's waters,'' 33 U.S.C. 1251(a). This rule advances the 
Clean Water Act's objective by defining ``waters of the United States'' 
to include waters that significantly affect the chemical, physical, or 
biological integrity of traditional navigable waters, the territorial 
seas, and interstate waters; and waters that meet the relatively 
permanent standard. The limitations in the definition ensure that the 
agencies will not assert jurisdiction where the effect on traditional 
navigable waters, the territorial seas, and interstate waters--i.e., 
the paragraph (a)(1) waters--is not significant. This rule is informed 
by the best available science on the functions provided by upstream 
waters, including wetlands, to restore and maintain the integrity of 
paragraph (a)(1) waters because the rule recognizes that upstream 
waters can have significant effects on such waters and enables the 
agencies to make science-informed decisions about such effects. This 
rule thus defines ``waters of the United States'' to include the 
familiar types of waters in the 1986 regulations--traditional navigable 
waters, interstate waters, impoundments, tributaries, the territorial 
seas, adjacent wetlands, and waters that do not fall within the other 
categories--while adding, where appropriate, a requirement that waters 
also meet either the significant nexus standard or the relatively 
permanent standard.
a. The Objective of the Clean Water Act To Protect Water Quality Must 
Be Considered When Defining ``Waters of the United States''
    A statute must be interpreted in light of the purposes Congress 
sought to achieve. See, e.g., Gen. Dynamics Land Sys., Inc. v. Cline, 
540 U.S. 581 (2004). When considering the scope of the Clean Water Act, 
the Supreme Court often begins with the objective of the Act and 
examines the relevant question through that lens. Thus, the agencies 
must consider the objective of the Clean Water Act in interpreting the 
scope of the statutory term ``waters of the United States.'' Here, 
Congress made its purpose crystal clear by stating its objective in the 
first section of the statute. The objective of the Clean Water Act is 
``to restore and maintain the chemical, physical, and biological 
integrity of the Nation's waters.'' 33 U.S.C. 1251(a). To adequately 
consider the Clean Water Act's statutory objective, a rule defining 
``waters of the United States'' must consider its effects on the 
chemical, physical, and biological integrity of the nation's waters. 
And--as the text and structure of the Clean Water Act, supported by 
legislative history and Supreme Court decisions, make clear--protecting 
the chemical, physical, and biological integrity of the nation's waters 
means protecting their water quality.
    The Clean Water Act begins with the objective in section 101(a) and 
establishes numerous programs all designed to protect the integrity of 
the nation's waters, ranging from permitting programs and enforcement 
authorities, to water quality standards and effluent limitations 
guidelines, to research and grant provisions. Section 102 of the Clean 
Water Act requires the Administrator to, after consultation, develop 
comprehensive programs for preventing, reducing, or eliminating the 
pollution of the navigable waters.
    One of the Clean Water Act's principal tools in protecting the 
integrity of the nation's waters is section 301(a), which generally 
prohibits ``the discharge of any pollutant by any person'' without a 
permit or other authorization under the Act. Other substantive 
provisions of the Clean Water Act that use the term ``navigable 
waters'' and are designed to meet the statutory objective include the 
section 402 permit program, the section 404 dredged and fill permit 
program, the section 311 oil spill prevention and response program, the 
section 303 water quality standards and total maximum daily load 
programs, and the section 401Tribal and State water quality 
certification process. Each of these programs is designed to protect 
water quality and, therefore, further the objective of the Clean Water 
Act. The question of Federal jurisdiction is foundational to most 
programs administered under the Clean Water Act. See section III.A.1 of 
this preamble.\44\
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    \44\ Additional provisions are also designed to achieve the 
Clean Water Act's statutory objective and use its specific language, 
including the definition of ``pollution,'' which the Act defines as 
``the man-made or man-induced alteration of the chemical, physical, 
biological, and radiological integrity of water.'' 33 U.S.C. 
1362(19).
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    Two recent Supreme Court Clean Water Act decisions, County of Maui, 
Hawaii v. Hawaii Wildlife Fund, 140 S. Ct. 1462, 1476 (2020) (``Maui'') 
and Nat'l Ass'n of Mfrs. v. Dep't of Defense, 138 S. Ct. 617, 624 
(2018) (``National Association of Manufacturers''), affirm that 
Congress used specific language in the definitions of the Clean Water 
Act in order to meet the objective of the Act, that the definition of 
``waters of the United States'' is fundamental to meeting the objective 
of the Act, and, therefore, that the objective of the Act must be 
considered in interpreting the term ``waters of the United States.''
    In Maui, the Supreme Court instructed that ``[t]he object in a 
given scenario will be to advance, in a manner consistent with the 
statute's language, the statutory purposes that Congress sought to 
achieve.'' 140 S. Ct. at 1476. The Court, in recognizing that 
Congress's purpose to `` `restore and maintain the . . . integrity of 
the Nation's waters' '' is ``reflected in the language of the Clean 
Water Act,'' also found that ``[t]he Act's provisions use specific 
definitional language to achieve this result,'' noting that among that 
definitional language is the phrase ``navigable waters.'' Id. at 1468-
69 (quoting 33 U.S.C. 1251(a)).\45\ Thus, in accordance with Maui, in 
interpreting the ``specific definitional language'' of the Clean Water 
Act, the agencies must ensure that they are advancing the statutory 
purposes Congress sought to achieve.
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    \45\ The Court explained:
    The Act's provisions use specific definitional language to 
achieve this result. First, the Act defines ``pollutant'' broadly, 
including in its definition, for example, any solid waste, 
incinerator residue, `` `heat,' '' `` `discarded equipment,' '' or 
sand (among many other things). Sec.  502(6), 86 Stat. 886. Second, 
the Act defines a ``point source'' as `` `any discernible, confined 
and discrete conveyance . . . from which pollutants are or may be 
discharged,' '' including, for example, any `` `container,' '' `` 
`pipe, ditch, channel, tunnel, conduit,' '' or `` `well.' '' Sec.  
502(14), id., at 887. Third, it defines the term `` `discharge of a 
pollutant' '' as `` `any addition of any pollutant to navigable 
waters [including navigable streams, rivers, the ocean, or coastal 
waters] from any point source.' '' Sec.  502(12), id., at 886.
    Maui, 140 S. Ct. at 1469.
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    In National Association of Manufacturers, the Court confirmed the 
importance of considering the plain language of the objective of the 
Clean Water Act when interpreting the

[[Page 3023]]

specific definitional language of the Act, and in particular when 
interpreting the definitional language ``waters of the United States.'' 
The Court identified section 301's prohibition on unauthorized 
discharges as one of the Clean Water Act's principal tools for 
achieving the objective and then identified the definition of ``waters 
of the United States'' as key to the scope of the Act: ``Congress 
enacted the Clean Water Act in 1972 `to restore and maintain the 
chemical, physical, and biological integrity of the Nation's waters.' 
[33 U.S.C.] 1251(a). One of the Act's principal tools in achieving that 
objective is [section] 1311(a), which prohibits `the discharge of any 
pollutant by any person,' except in express circumstances. . . . 
Because many of the Clean Water Act's substantive provisions apply to 
`navigable waters,' the statutory phrase `waters of the United States' 
circumscribes the geographic scope of the Act in certain respects.'' 
138 S. Ct. 617, 624. Thus, consideration of the objective of the Clean 
Water Act is of particular importance when defining the foundational 
phrase ``waters of the United States.''
    Many other Supreme Court decisions confirm the importance of 
considering the Clean Water Act's objective. When faced with questions 
of statutory interpretation on the scope of the Clean Water Act, many 
Supreme Court decisions begin with the objective of the Act and examine 
the relevant question through that lens. See, e.g., PUD No. 1 of 
Jefferson Cty v. Washington Dep't of Ecology, 511 U.S. 700, 704 (1994) 
(interpreting the scope of Clean Water Act section 401 and finding that 
the Act ``is a comprehensive water quality statute designed to `restore 
and maintain the chemical, physical, and biological integrity of the 
Nation's waters,' '' that ``[t]he Act also seeks to attain `water 
quality which provides for the protection and propagation of fish, 
shellfish, and wildlife,' '' and that ``[t]o achieve these ambitious 
goals, the Clean Water Act establishes distinct roles for the Federal 
and State Governments''); EPA v. California ex rel. State Water 
Resources Control Bd., 426 U.S. 200, 203, 205 n.12 (1976) (``In 1972, 
prompted by the conclusion of the Senate Committee on Public Works that 
`the Federal water pollution control program . . . has been inadequate 
in every vital aspect,' Congress enacted the [Clean Water Act], 
declaring `the national goal that the discharge of pollutants into the 
navigable waters be Eliminated by 1985.'''); Arkansas v. Oklahoma, 503 
U.S. 91, 101 (1992) (reviewing the scope of EPA's authority to issue a 
permit affecting a downstream State and finding that the Clean Water 
Act ``anticipates a partnership between the States and the Federal 
Government, animated by a shared objective: `to restore and maintain 
the chemical, physical, and biological integrity of the Nation's 
waters' ''); S.D. Warren Co. v. Maine Bd. of Envtl. Protection, 126 S. 
Ct. 1843, 1852-53 (2006) (interpreting the scope of ``discharge'') 
(``Congress passed the Clean Water Act to `restore and maintain the 
chemical, physical, and biological integrity of the Nation's waters,' 
33 U.S.C. [section] 1251(a) . . . .''); Int'l Paper Co. v. Ouellette, 
479 U.S. 481, 492-93 (1987) (``Congress intended the 1972 Act 
amendments to `establish an all-encompassing program of water pollution 
regulation.' . . . The Act applies to all point sources and virtually 
all bodies of water, and it sets forth the procedures for obtaining a 
permit in great detail. . . . Given that the Act itself does not speak 
directly to the issue, the Court must be guided by the goals and 
policies of the Act in determining whether it in fact pre-empts an 
action based on the law of an affected State.'').
    Along with Maui and National Association of Manufacturers, these 
cases confirm that, for purposes of a rulemaking revising the 
definition of ``waters of the United States,'' the agencies must 
consider the rule's effect on the chemical, physical, and biological 
integrity of the nation's waters--i.e., on the quality of those waters. 
The Supreme Court in Riverside Bayview explained the inherent link 
between the Clean Water Act's objective and water quality: ``This 
objective incorporated a broad, systemic view of the goal of 
maintaining and improving water quality: as the House Report on the 
legislation put it, `the word ``integrity'' . . . refers to a condition 
in which the natural structure and function of ecosystems [are] 
maintained.' '' 474 U.S. at 132 (citations omitted).
    The statutory structure further confirms that ``waters of the 
United States'' must be interpreted to account for the Clean Water 
Act's broader objective of promoting water quality. The Act is replete 
with 90 references to water quality--from the goals set forth to meet 
the statutory objective to the provisions surrounding research, 
effluent limitations, and water quality standards. See, e.g., 33 U.S.C. 
1251(a)(2) (``[I]t is the national goal that wherever attainable, an 
interim goal of water quality which provides for the protection and 
propagation of fish, shellfish, and wildlife and provides for 
recreation in and on the water be achieved. . . .''), 1254(b)(6) 
(providing that the Administrator shall collect ``basic data on 
chemical, physical, and biological effects of varying water quality''), 
1311(b)(1)(C) (requiring permits to have limits as stringent as 
necessary to meet water quality standards), 1313(c) (providing that 
water quality standards ``shall be such as to protect the public health 
or welfare, enhance the quality of water and serve the purposes of this 
[Act]''). And Congress was clear that ``[t]he development of 
information which describes the relationship of pollutants to water 
quality is essential for carrying out the objective of the Act.'' S. 
Rep. No. 92-414 at 47 (1972), as reprinted in 1972 U.S.C.C.A.N. 3668, 
3716; see also id. at 3717 (``Water quality is intended to refer to the 
biological, chemical and physical parameters of aquatic ecosystems, and 
is intended to include reference to key species, natural temperature 
and current flow patterns, and other characteristics which help 
describe ecosystem integrity. . . . The criteria will allow the 
translation of the narrative of the general objective of the Act to 
specific and precise parameters.''); id. at 3742 (``The Committee has 
added a definition of pollution to further refine the concept of water 
quality measured by the natural chemical, physical and biological 
integrity.''). As the Sixth Circuit explained shortly after the 1972 
enactment of the Clean Water Act: ``It would, of course, make a mockery 
of [Congress's] powers if its authority to control pollution was 
limited to the bed of the navigable stream itself. The tributaries 
which join to form the river could then be used as open sewers as far 
as federal regulation was concerned. The navigable part of the river 
could become a mere conduit for upstream waste.'' United States v. 
Ashland Oil & Transp. Co., 504 F.2d 1317, 1326 (6th Cir. 1974).
    To be clear, the objective of the Clean Water Act is not the only 
factor relevant to determining the scope of the Act. Rather, in light 
of the precise language of the definitions in the Act, the importance 
of water quality to the statute as a whole, and Supreme Court decisions 
affirming that consideration of the objective of the Act is of primary 
importance in defining its scope, the agencies conclude that a rule 
defining ``waters of the United States'' must substantively consider 
the effects of a revised definition on the integrity of the nation's 
waters and advance the protection of the quality of those waters. As 
discussed further below, this rule

[[Page 3024]]

properly considers and advances the objective of the Clean Water Act 
because the science conclusively demonstrates that upstream waters, 
including wetlands, can affect the quality of downstream waters and 
ensures application of Clean Water Act water quality programs to 
upstream waters when their effect on downstream traditional navigable 
waters, territorial seas, and interstate waters is significant.
b. This Rule Is Founded on the 1986 Regulations, Which Advance the 
Objective of the Clean Water Act
    The 1986 regulations--which are substantially the same as the 1977 
regulations--represented the agencies' interpretation of the Clean 
Water Act in light of its objective and their scientific knowledge 
about aquatic ecosystems. In this rule, the agencies are exercising 
their authority to construe ``waters of the United States'' to mean the 
waters defined by the familiar 1986 regulations, with amendments to 
reflect the agencies' construction of limitations on the scope of 
``waters of the United States,'' based on the law, the science, and 
agency expertise. Of particular import, the agencies are limiting the 
scope of the longstanding regulatory categories by adding a requirement 
that tributaries, adjacent wetlands (that are adjacent to waters other 
than paragraph (a)(1) waters), and lakes and ponds, streams, and 
wetlands that are not identified in paragraphs (a)(1) through (4) meet 
either the relatively permanent standard or the significant nexus 
standard as established in this rule. The agencies also considered the 
extensive public comment on the proposed rule in developing this final 
rule.
    The best available science confirms that the 1986 regulations 
remain a reasonable foundation for a definition of ``waters of the 
United States'' that furthers the water quality objective of the Clean 
Water Act. See Technical Support Document. This section of the preamble 
describes the agencies' historic rationale for the 1986 regulation and 
its regulatory categories and describes the latest science that 
supports the conclusion that the categories of waters identified in the 
1986 regulations provide functions that restore and maintain the 
chemical, physical, and biological integrity of traditional navigable 
waters, the territorial seas, and interstate waters.
    The agencies' historic regulations, eventually promulgated and 
referred to as the 1986 regulations, were based on the agencies' 
construction of the scope of the Clean Water Act and their scientific 
and technical judgment about which waters needed to be protected to 
restore and maintain the chemical, physical, and biological integrity 
of traditional navigable waters, the territorial seas, and interstate 
waters (i.e., the paragraph (a)(1) waters). For more than 45 years, the 
agencies recognized the need to protect ``the many tributary streams 
that feed into the tidal and commercially navigable waters . . . since 
the destruction and/or degradation of the physical, chemical, and 
biological integrity of each of these waters is threatened by the 
unregulated discharge of dredged or fill material.'' See, e.g., 42 FR 
37122, 37123 (July 19, 1977). The agencies have also long recognized 
that the nation's wetlands are ``a unique, valuable, irreplaceable 
water resource. . . . Such areas moderate extremes in waterflow, aid in 
the natural purification of water, and maintain and recharge the ground 
water resource.'' EPA, Protection of Nation's Wetlands: Policy 
Statement, 38 FR 10834 (May 2, 1973). In Riverside Bayview, the Supreme 
Court acknowledged that the agencies were interpreting the Clean Water 
Act consistent with its objective and based on their scientific 
expertise:

    In view of the breadth of federal regulatory authority 
contemplated by the Act itself and the inherent difficulties of 
defining precise bounds to regulable waters, the Corps' ecological 
judgment about the relationship between waters and their adjacent 
wetlands provides an adequate basis for a legal judgment that 
adjacent wetlands may be defined as waters under the Act.

474 U.S. at 134.
    And, as the Corps stated in promulgating the 1977 definition, 
``[t]he regulation of activities that cause water pollution cannot rely 
on . . . artificial lines, however, but must focus on all waters that 
together form the entire aquatic system. Water moves in hydrologic 
cycles, and the pollution of . . . part of the aquatic system . . . 
will affect the water quality of the other waters within that aquatic 
system.'' 42 FR 37128 (July 19, 1977).
    Thus, this rule includes the categories long identified by the 
agencies as affecting the water quality of paragraph (a)(1) waters, 
including tributaries, adjacent wetlands, impoundments, and waters that 
do not fall within any of the more specific categories of the 
definition (a category that has been modified and codified in this rule 
as paragraph (a)(5) waters).
    As discussed below, however, while these longstanding categories 
continue to provide a reasonable foundation for this rule, this rule 
codifies limitations on these categories based on the agencies' 
interpretation of the Clean Water Act. To be clear, this rule does not 
automatically include all tributaries, adjacent wetlands, and waters 
assessed under paragraph (a)(5) as jurisdictional waters. Rather, the 
agencies conclude that utilizing these longstanding, familiar 
categories of waters, subject to the relatively permanent or 
significant nexus jurisdictional standards, is consistent with the best 
available science because the significant nexus standard established in 
this rule is based on an assessment of the effects of waters in these 
categories on the water quality of paragraph (a)(1) waters. In 
addition, the agencies believe that waters that meet the relatively 
permanent standard individually and cumulatively provide many functions 
that benefit the integrity of paragraph (a)(1) waters. See section 
IV.A.3.a.ii of this preamble. This rule does categorically include 
wetlands adjacent to paragraph (a)(1) waters. Riverside Bayview, 474 
U.S. at 135; see also Rapanos, 547 U.S. at 780 (Kennedy, J., concurring 
in the judgment) (``As applied to wetlands adjacent to navigable-in-
fact waters, the Corps' conclusive standard for jurisdiction rests upon 
a reasonable inference of ecologic interconnection, and the assertion 
of jurisdiction for those wetlands is sustainable under the Act by 
showing adjacency alone. That is the holding of Riverside Bayview.''). 
This rule enables the agencies to make science-informed determinations 
of whether or not a water that falls within these categories meets 
either jurisdictional standard and therefore satisfies the definition 
of ``waters of the United States'' on a case-specific basis. For a 
detailed discussion of implementation of adjacent wetlands under this 
rule, see section IV.A.4 of this preamble; for additional guidance to 
landowners on jurisdictional determinations, see section IV.C.10 of 
this preamble.
i. The Agencies' Longstanding Interpretation That Tributaries Can Be 
``Waters of the United States'' Is a Reasonable Foundation for This 
Rule
    The agencies have long construed the Clean Water Act to include 
tributaries as ``waters of the United States.'' In 1973, EPA's General 
Counsel issued an opinion upon which the agency's subsequent rulemaking 
was based that tributaries were included within the term ``navigable 
waters,'' finding that ``this broad interpretation is well grounded in 
the language of the statute and in the legislative history, and 
comports with the expressed intent of Congress to `restore and maintain 
the chemical, physical, and biological integrity of the Nation's 
waters.' '' Envtl.

[[Page 3025]]

Prot. Agency, Off. Gen. Counsel, Meaning of the Term ``Navigable 
Waters'' (February 13, 1973), 1973 WL 21937. The Corps explained in 
1977 that its regulations necessarily encompassed ``the many tributary 
streams that feed into the tidal and commercially navigable waters'' 
because ``the destruction and/or degradation of the physical, chemical, 
and biological integrity of each of these waters is threatened by the 
unregulated discharge of dredged or fill material.'' 42 FR 37123 (July 
19, 1977).
    The conclusion that the Clean Water Act includes tributaries is 
consistent with the structure and history of the statute. The Clean 
Water Act was not ``merely another law `touching interstate waters,' '' 
but rather ``a `total restructuring' and `complete rewriting' of [then] 
existing water pollution legislation.'' City of Milwaukee v. Illinois, 
451 U.S. 304, 317 (1981) (citations omitted). Congress concluded that 
prior measures had been ``inadequate in every vital aspect,'' and it 
enacted a wholly new scheme of point-source-based pollution controls. 
EPA v. California ex rel. State Water Res. Control Bd., 426 U.S. 200, 
203 (1976) (citation omitted). The Clean Water Act thus reflected 
Congress's fundamental dissatisfaction with prior law.
    Even before it enacted the 1972 Clean Water Act amendments, 
Congress had recognized, and had acted to address, the danger that 
pollution of tributaries may impair the quality of traditional 
navigable waters downstream. Prior to those amendments, the Federal 
Water Pollution Control Act established procedures for abatement of 
``(t)he pollution of interstate or navigable waters in or adjacent to 
any State or States (whether the matter causing or contributing to such 
pollution is discharged directly into such waters or reaches such 
waters after discharge into a tributary of such waters).'' 33 U.S.C. 
1160(a) (1970) (emphasis added). Under specified circumstances, the 
Attorney General was authorized to bring suit on behalf of the United 
States ``to secure abatement of the pollution.'' 33 U.S.C. 1160(g) 
(1970). Indeed, the regulation of tributaries as part and parcel of a 
Federal effort to protect traditional navigable waters has been a 
feature of Federal law for over 100 years. Since its enactment as 
section 13 of the Rivers and Harbors Appropriation Act of 1899 (RHA), 
Ch. 425, section 13, 30 stat. 1152, the Refuse Act of 1899 has 
prohibited the discharge of refuse material into any ``navigable water 
of the United States or into any tributary of any navigable water of 
the United States,'' as well as depositing refuse material ``on the 
bank of any navigable water, or on the bank of any tributary of any 
navigable water.'' 33 U.S.C. 407. That provision does not limit the 
covered ``tributar[ies]'' to those that are themselves used or 
susceptible to use for navigation.
    Thus, well over a hundred years ago, Congress understood the 
necessity of protecting tributaries in order to protect traditional 
navigable waters and recognized its authority over those tributaries, 
and in the Clean Water Act Congress sought to expand protection of the 
nation's waters. It would therefore be unreasonable for the agencies to 
construe the Clean Water Act, with its comprehensive focus on limiting 
discharges of pollutants to ``waters of the United States'' and 
restoring and maintaining the chemical, physical, and biological 
integrity of the nation's waters, to exclude tributaries to traditional 
navigable waters, the territorial seas, and interstate waters.
    Section 404(g) of the Clean Water Act further supports the 
agencies' interpretation that the Act covers such tributaries. Section 
404(g) authorizes States to administer their own permit programs over 
certain waters. Section 404(g)(1) provides, in relevant part, that any 
State ``desiring to administer its own individual and general permit 
program for the discharge of dredged or fill material into the 
navigable waters (other than those waters which are presently used, or 
are susceptible to use in their natural condition or by reasonable 
improvement as a means to transport interstate or foreign commerce . . 
. including wetlands adjacent thereto)'' may submit a description of 
this proposed program to EPA. 33 U.S.C. 1344(g)(1).\46\ Section 
404(g)(1)'s reference to navigable waters ``other than those waters 
used or susceptible to use'' for transporting commerce and their 
adjacent wetlands plainly indicates that the Clean Water Act covers 
more than the waters in this parenthetical.
---------------------------------------------------------------------------

    \46\ The Corps retains permitting authority over the ``waters of 
the United States'' that States cannot or do not assume.
---------------------------------------------------------------------------

    The Supreme Court has also recognized the relevance of section 
404(g) to interpreting the scope of Clean Water Act jurisdiction. In 
Riverside Bayview, while the Supreme Court stated that section 404(g) 
``does not conclusively determine the construction to be placed on the 
use of the term `waters' elsewhere in the Act,'' the Court went on to 
say with respect to the significance of section 404(g) that ``the 
various provisions of the Act should be read in pari materia [i.e., 
construed together],'' ultimately concluding that section 404(g) 
``suggest[s] strongly that the term `waters' as used in the Act'' 
supports the Corps' interpretation of ``waters of the United States'' 
to include wetlands. 474 U.S. at 138 n.11 (emphasis added). While the 
Court in SWANCC did not read section 404(g) to definitively answer the 
question of the scope of ``waters of the United States,'' the Court 
offered a hypothesis that ``Congress simply wanted to include all 
waters adjacent to `navigable waters,' such as non-navigable 
tributaries and streams.'' 531 U.S. at 171. And all members of the 
Supreme Court agreed with the observation of the Rapanos plurality that 
the 1977 Clean Water Act's authorization for States to administer the 
section 404 program for ``navigable waters . . . other than'' those 
used or suitable for use ``to transport interstate or foreign 
commerce,'' 547 U.S. at 731 (quoting 33 U.S.C. 1344(g)(1)), ``shows 
that the Act's term `navigable waters' includes something more than 
traditional navigable waters.'' Id. In light of the history of the Act 
as well as Congress's clear understanding of the relationship between 
tributaries and traditional navigable waters, tributaries--whether or 
not they themselves are traditional navigable waters--are an obvious 
candidate for the Clean Water Act's broader coverage. As noted above, 
even long before 1972, Congress had addressed the danger that pollution 
of tributaries may impair the quality of traditional navigable waters 
downstream, and it is implausible to suppose that Congress's landmark 
1972 legislation actually reduced the scope of the prior statutes.
    Construing ``waters of the United States'' to include tributaries 
of traditional navigable waters, the territorial seas, interstate 
waters, or impoundments of ``waters of the United States'' is also 
consistent with the discussion of tributaries in the Clean Water Act's 
legislative history. The Senate Report accompanying the 1972 Act states 
that ``navigable waters'' means ``the navigable waters of the United 
States, portions thereof, tributaries thereof, and includes the 
territorial seas and the Great Lakes.'' S. Rep. No. 92-414, at 77 
(1971), as reprinted in 1972 U.S.C.C.A.N. 3668, 3742 (emphasis added). 
Congress thus restated that ``reference to the control requirements 
must be made to the navigable waters, portions thereof, and their 
tributaries.'' Id. at 3743 (emphasis added).
    In addition, this rule and the 1986 regulations construe the 
statute not to

[[Page 3026]]

distinguish between human-made or human-altered tributaries and natural 
tributaries. This construction is consistent with the text of the 
statute and science. Most obviously, such a distinction would render 
superfluous section 404's exception for ``the discharge of dredged or 
fill material . . . for the . . . maintenance of drainage ditches,'' 
section 404(f)(1)(C), because if human-made or human-altered 
tributaries were not included, drainage ditches would not be covered in 
the first place. More broadly, many of the nation's urban waterways are 
channelized, and the Clean Water Act has long been understood to 
encompass ``natural, modified, or constructed'' tributaries of other 
covered waters. 80 FR 37078 (June 29, 2015). For example, many of the 
streams in Houston, Texas, have been channelized, culverted, or 
otherwise altered over time, in part for flood control purposes, and 
the Clean Water Act protects many of these human-modified streams. 
Removing the Clean Water Act's protections for these tributaries could 
increase contributions of nutrients, sediment, and other pollutants 
downstream to paragraph (a)(1) waters, such as the Trinity River. Such 
an approach would also affect millions of miles of other such 
tributaries, undermining the integrity of paragraph (a)(1) waters 
throughout the country.
    Moreover, the Clean Water Act's specialized definition of 
``navigable waters'' does not turn on any such distinctions between 
natural and human-made or -altered tributaries, which have no bearing 
on a tributary's capacity to carry water (and pollutants) to 
traditional navigable waters, the territorial seas, or interstate 
waters. See, e.g., Technical Support Document section III.A.iv 
(explaining that manmade ditches ``perform many of the same functions 
as natural tributaries,'' including ``convey[ing] water that carries 
nutrients, pollutants, and other constituents, both good and bad, to 
downstream traditional navigable waters, the territorial seas, and 
interstate waters''). Such a distinction would also be inconsistent 
with Rapanos. That decision addressed consolidated cases involving 
wetlands connected to traditional navigable waters by ``ditches or man-
made drains.'' Rapanos, 547 U.S. at 729 (plurality opinion). The 
Rapanos plurality concluded that the cases should be remanded for the 
lower courts to determine whether the channels at issue satisfied the 
plurality's jurisdictional standard, and those further lower-court 
proceedings would have been superfluous if the manmade character of the 
ditches and drains had precluded their coverage as ``waters of the 
United States.''
    As discussed below and further in section III.A of the Technical 
Support Document, the best available science supports the 1986 
regulations' conclusions, and the agencies' construction of the Clean 
Water Act in this rule, about the importance of tributaries to the 
water quality of downstream paragraph (a)(1) waters: tributaries 
provide natural flood control, help sustain flow downstream, recharge 
groundwater, trap sediment, store and transform pollutants, decrease 
high levels of chemical contaminants, recycle nutrients, create and 
maintain biological diversity, and sustain the biological productivity 
of downstream rivers, lakes, and estuaries.
ii. The Agencies' Longstanding Interpretation of Adjacent Wetlands as 
``Waters of the United States'' Is a Reasonable Foundation for This 
Rule
    For more than four decades, the agencies have construed the 
``waters of the United States'' to include wetlands adjacent to other 
jurisdictional waters. Wetlands, such as swamps, bogs, marshes, and 
fens, are ``transitional areas between terrestrial and aquatic 
ecosystems'' characterized by sustained inundation or saturation with 
water. Science Report at 2-5. Wetlands play a critical role in 
regulating water quality. Among other things, they provide flood 
control and trap and filter sediment and other pollutants that would 
otherwise be carried to downstream waters. See National Research 
Council, Wetlands: Characteristics and Boundaries 35, 38 (1995) (NRC 
Report, available at https://nap.nationalacademies.org/catalog/4766/wetlands-characteristics-and-boundaries; Technical Support Document 
section III.B.
    The Corps published regulations to implement the section 404 
permitting program in 1974. 39 FR 12115 (April 3, 1974). At that time, 
the Corps took the view that for purposes of section 404 ``navigable 
waters'' was an established term of art for waters that are subject to 
Congress's power to regulate interstate channels of commerce, and that 
the term should be given that meaning in the Clean Water Act--
notwithstanding the specialized definition of ``navigable waters'' in 
the Act. Id. The Corps therefore asserted jurisdiction under section 
404 only over the waters subject to section 10 of the Rivers and 
Harbors Act of 1899. Id. at 12119.
    Reviewing courts, members of Congress, and EPA disagreed with the 
Corps' initial approach. See, e.g., United States v. Ashland Oil & 
Transp. Co., 504 F.2d 1317, 1325 (6th Cir. 1974); H.R. Rep. No. 1396, 
93d Cong., 2d Sess. 23-27 (1974). In fact, EPA had previously 
promulgated a rule defining ``waters of the United States'' far more 
broadly than the Corps' regulations. 38 FR 13528 (May 22, 1973). 
Ultimately, the Corps was ordered to adopt new regulations recognizing 
the agency's ``full regulatory mandate.'' NRDC, Inc. v. Callaway, 392 
F. Supp. 685, 686 (D.D.C. 1975).
    The Corps responded by broadening its definition of ``navigable 
waters'' in a phased approach under which all of the waters in the 
final regulation were ``waters of the United States,'' but the Corps 
would begin regulating activities within each type of ``waters of the 
United States'' in phases: Phase I, which was effective immediately, 
covered ``coastal waters and coastal wetlands contiguous or adjacent 
thereto or into inland navigable waters of the United States [a term 
for waters protected under the Rivers and Harbors Act] and freshwater 
wetlands contiguous or adjacent thereto''; Phase II, effective after 
July 1, 1976, covered ``primary tributaries, freshwater wetlands 
contiguous or adjacent to primary tributaries, and lakes''; and Phase 
III, effective after July 1, 1977, covered ``discharges . . . into any 
navigable water'' including intrastate lakes and rivers and their 
adjacent wetlands. 40 FR 31320, 31324, 31326 (July 25, 1975). The Corps 
defined ``adjacent'' to mean ``bordering, contiguous, or neighboring,'' 
and specified that ``[w]etlands separated from other waters of the 
United States by man-made dikes or barriers, natural river berms, beach 
dunes and the like are `adjacent wetlands.' '' 42 FR 37122, 37144 (July 
19, 1977). The regulations also defined ``wetlands'' to mean ``those 
areas that are inundated or saturated by surface or ground water at a 
frequency and duration sufficient to support, and that under normal 
circumstances do support, a prevalence of vegetation typically adapted 
for life in saturated soil conditions.'' Id. The agencies have thus 
interpreted the term ``waters of the United States'' to include 
wetlands since at least 1975.\47\
---------------------------------------------------------------------------

    \47\ The agencies' interpretation of ``waters of the United 
States'' as including wetlands is consistent not only with the 
history and text of Clean Water Act section 404(g), but also with 
other parts of the statute and of the United States Code. For 
example, in the Lake Champlain Basin Program, Congress referred to 
``streams, rivers, lakes, and other bodies of water, including 
wetlands.'' 33 U.S.C. 1270(g)(2) (emphasis added). Congress has also 
referred to ``streams, rivers, wetlands, other waterbodies, and 
riparian areas,'' 33 U.S.C. 2336(b)(2) (emphasis added), and defined 
``coastal waters'' to mean the waters of the Great Lakes 
``including'' portions of other ``bodies of water'' with certain 
features, ``including wetlands,'' id. at 2802(5).

---------------------------------------------------------------------------

[[Page 3027]]

    Reacting to the Corps' broadened definition, leading up to the 1977 
Amendments, Congress considered proposals to limit the geographic reach 
of section 404. ``In both Chambers, debate on the proposals to narrow 
the definition of navigable waters centered largely on the issue of 
wetlands preservation.'' SWANCC, 531 U.S. at 170. A version of that 
legislation, passed by the House, would have redefined ``navigable 
waters'' for purposes of section 404 to mean a limited set of 
traditional navigable waters and their adjacent wetlands. H.R. 3199, 
95th Cong. section 16 (1977). But many legislators objected to the 
proposed changes. When Congress rejected the attempt to limit the 
geographic reach of section 404, it was well aware of the 
jurisdictional scope of EPA and the Corps' definition of ``waters of 
---------------------------------------------------------------------------
the United States.'' For example, Senator Baker stated:

    Interim final regulations were promulgated by the [C]orps [on] 
July 25, 1975. . . . Together the regulations and [EPA] guidelines 
established a management program that focused the decision-making 
process on significant threats to aquatic areas while avoiding 
unnecessary regulation of minor activities. On July 19, 1977, the 
[C]orps revised its regulations to further streamline the program 
and correct several misunderstandings. . . .
    Continuation of the comprehensive coverage of this program is 
essential for the protection of the aquatic environment. The once 
seemingly separable types of aquatic systems are, we now know, 
interrelated and interdependent. We cannot expect to preserve the 
remaining qualities of our water resources without providing 
appropriate protection for the entire resource.
    Earlier jurisdictional approaches under the [Rivers and Harbors 
Act] established artificial and often arbitrary boundaries . . . .

123 Cong. Rec. 26,725 (1977). Legislators were concerned the proposed 
changes were an ``open invitation'' to pollute waters. Id. (remarks of 
Sen. Hart); see also, e.g., id. at 26,714-26,716. The proposal was 
ultimately voted down on the Senate floor. Id. at 26,728; cf. S. Rep. 
No. 370, 95th Cong., 1st Sess. 10 (1977) (hereinafter, ``1977 Senate 
Report''); Riverside Bayview, 474 U.S. at 136-137 (noting that 
``efforts to narrow the definition of `waters' were abandoned; the 
legislation as ultimately passed, in the words of Senator Baker, 
`[retained] the comprehensive jurisdiction over the Nation's waters'' 
(citation omitted)). Federal preservation of wetlands was at the heart 
of the debate over passage of the 1977 Act, with good reason. See 1977 
Senate Report at 10 (``There is no question that the systematic 
destruction of the Nation's wetlands is causing serious, permanent 
ecological damage. The wetlands and bays, estuaries and deltas are the 
Nation's most biologically active areas. They represent a principal 
source of food supply. They are the spawning grounds for much of the 
fish and shellfish which populate the oceans, and they are passages for 
numerous [ ] game fish. They also provide nesting areas for a myriad of 
species of bird and wildlife. The unregulated destruction of these 
areas is a matter which needs to be corrected and which implementation 
of section 404 has attempted to achieve.''). Earlier Federal and State 
policy that encouraged filling wetlands had led to destruction of 
roughly 117 million acres of wetlands in the contiguous United States, 
or more than half the original total. See T.E. Dahl & Gregory J. 
Allord, ``History of Wetlands in the Conterminous United States,'' in 
National Water Summary on Wetland Resources at 19 (1996, available at 
https://pubs.usgs.gov/wsp/2425/report.pdf).
    Congress instead modified the Clean Water Act in other ways to 
respond to concerns about the scope of Federal authorities. Congress 
exempted certain agricultural and silvicultural activities from the 
section 404 permitting program. See 1977 Act section 67(b), 91 Stat. 
1600 (33 U.S.C. 1344(f)(1)(A)). In addition, Congress authorized the 
Corps to issue general permits to streamline the permitting process. 
Id. (33 U.S.C. 1344(e)(1)). And importantly for understanding the scope 
of ``waters of the United States,'' Congress modified section 404 in a 
way that incorporated into the statutory text an explicit endorsement 
of the Corps' regulation defining ``waters of the United States,'' 
including its inclusion of adjacent wetlands. Specifically, the 1977 
Act section 67(b), 91 Stat. 1601, establishing section 404(g), allowed 
Tribes and States to assume responsibility for the issuance of section 
404 permits. As Congress explained in the legislative history, under 
section 404(g) States could administer a permitting program for the 
discharge of dredged or fill material into ``phase II and III waters'' 
following EPA approval, but the Corps would retain jurisdiction over 
``those waters defined as the phase I waters in the Corps . . . 1975 
regulations, with the exception of waters considered navigable solely 
because of historical use.'' 123 Cong. Rec. 38,969 (December 15, 1977); 
H.R. Conf. Rep. No. 830, 95th Cong., 1st Sess. 101 (1977), reprinted in 
3 Legis. History 1977, at 185, 285. Accordingly, through section 
404(g), Congress demonstrated its understanding of the Corps' 
regulations and endorsed the scope of their coverage--allowing States 
to assume authority to administer the Clean Water Act as it pertained 
to the waters contained in phase II and III of the Corps' regulations 
(Phase II, effective after July 1, 1976, covered ``primary tributaries, 
freshwater wetlands contiguous or adjacent to primary tributaries, and 
lakes'' and Phase III, effective after July 1, 1977, covered 
``discharges . . . into any navigable water'' including intrastate 
lakes and rivers and their adjacent wetlands. 40 FR 31320, 31324, 31326 
(July 25, 1975)), and reserving for the Corps alone authority over the 
waters contained in phase I of the Corps' regulations.
    With respect specifically to the inclusion of adjacent wetlands, 
Congress was explicit in the text of the Clean Water Act. The text of 
section 404(g) authorizes States and Tribes to administer the section 
404 permitting program covering ``the discharge of dredged or fill 
material into the navigable waters (other than those waters which are 
presently used, or are susceptible to use in their natural condition or 
by reasonable improvement as a means to transport interstate or foreign 
commerce . . . including wetlands adjacent thereto).'' 33 U.S.C. 
1344(g)(1) (emphasis added); see 33 U.S.C. 1377(e) (extension to 
Tribes). The italicized reservation of authority to the Corps in 
section 404(g) presupposed that ``wetlands adjacent'' to a subset of 
traditional navigable waters were subject to the section 404 program, 
since otherwise the exclusion of those wetlands from the Tribes' and 
States' potential permitting authority would have been superfluous. 
Other language in the 1977 legislative record confirms that 
understanding. See 1977 Senate Report 10 (stating that committee wished 
to ``maintain[ ]'' coverage of wetlands); H.R. Conf. Rep. No. 830, 95th 
Cong., 1st Sess. 98, 104 (1977) (stating that the Corps will 
``continue'' to exercise section 404 jurisdiction over ``adjacent 
wetlands'').
    Moreover, with respect to which wetlands are adjacent, by using the 
pre-existing term ``adjacent'' wetlands from the Corps' 1977 
regulations, Congress signaled its intent to incorporate the Corps' 
regulatory conception of adjacency. ``When a statutory term is 
`obviously transplanted from another legal source,' it `brings the old 
soil with it.' '' Taggart v. Lorenzen, 139 S. Ct. 1795, 1801 (2019) 
(citation omitted). Here, that soil includes the full breadth of the 
agencies' definition of ``adjacent'': bordering, contiguous, or 
neighboring, as well as wetlands behind a berm or

[[Page 3028]]

barrier. That definition accords with the term's plain meaning. 
Contemporaneous dictionaries defined the term ``adjacent'' in ways that 
do not require direct abutment. See Black's Law Dictionary at 62 (rev. 
4th ed. 1968) (``Lying near or close to; sometimes, contiguous; 
neighboring. Adjacent implies that the two objects are not widely 
separated, though they may not actually touch[.]'' (capitalization 
altered; citation and emphasis omitted)); The American Heritage 
Dictionary of the English Language at 16 (1975) (``Close to; next to; 
lying near; adjoining.''); Webster's New International Dictionary of 
the English Language at 32 (2d ed. 1958) (``Lying near, close, or 
contiguous; neighboring; bordering on.'' (emphasis omitted)).
    Congress has on a number of additional occasions responded to 
concerns about the breadth of the scope of Federal authorities not by 
narrowing the scope of ``waters of the United States,'' but by 
excluding particular types and sources of discharges of pollutants from 
the NPDES program or from Clean Water Act jurisdiction altogether. For 
example, the 1987 Water Quality Act (WQA) added section 402(l)(2) to 
the Clean Water Act. This new section prohibits EPA and the states from 
requiring NPDES permits for uncontaminated stormwater discharges from 
oil and gas exploration, production, processing or treatment 
operations, or transmission facilities. Later, section 323 of the 
Energy Policy Act of 2005 added a new provision to Clean Water Act 
section 502 defining the term ``oil and gas exploration, production, 
processing, or treatment operations or transmission facilities.'' The 
1987 WQA also enacted a new section 402(p) of the Act that established 
a comprehensive new program for stormwater regulation. In that section, 
Congress made clear that only some stormwater point source discharges 
need NPDES permit coverage--those from industrial activity, from large 
and medium municipalities, and that EPA or a State designates by 
rulemaking or adjudication to protect water quality or because the 
discharges contribute to violations of water quality standards or are 
significant contributors of pollutants. Congress has also taken 
numerous actions to amend the Clean Water Act to address discharges 
from vessels. The 1972 version of the Act excluded ``sewage from 
vessels'' from the definition of ``pollutant'' thus exempting it from 
the permitting regime in favor of regulatory standards of performance. 
See 33 U.S.C. 1322(b), 1362(6). In 1996, Congress similarly excluded 
most discharges from vessels of the Armed Forces and tasked EPA and the 
Department of Defense to jointly promulgate uniform national discharge 
standards instead. See 33 U.S.C. 1322(n), 1362(6). In 2008, Congress 
passed the Clean Boating Act, which exempted discharges incidental to 
the normal operation of recreational vessels of all sizes from Clean 
Water Act permitting requirements, in favor of EPA regulations. See 33 
U.S.C. 1322(o)(1)(B); see also 33 U.S.C. 1342(r). And in 2018, Congress 
enacted the Vessel Incidental Discharge Act which exempted from NPDES 
routine discharges from many other types of vessels including small 
vessels, fishing vessels, and commercial vessels larger than 79 feet. 
See 33 U.S.C. 1322(p)(9)(C)(ii).
    Case law also supports the agencies' construction of the Clean 
Water Act to cover adjacent wetlands as defined by the agencies. In 
Riverside Bayview, the Supreme Court considered the ``language, 
policies, and history'' of the Clean Water Act, including the 
amendments in the 1977 Act, and unanimously upheld the Corps' exercise 
of Clean Water Act jurisdiction over such adjacent wetlands. 474 U.S. 
at 139. The Court held that the Corps' regulation defining ``the waters 
of the United States'' to include wetlands adjacent to navigable waters 
``is valid as a construction'' of the Clean Water Act. Id. at 131. The 
Court first observed that ``between open waters and dry land may lie 
shallows, marshes, mudflats, swamps, bogs--in short, a huge array of 
areas that are not wholly aquatic but nevertheless fall far short of 
being dry land.'' Id. at 132. To administer the statute, the Corps 
therefore ``must necessarily choose some point at which water ends and 
land begins.'' Id. The Court further explained that, in drawing that 
jurisdictional line, the Corps may take into account ``the evident 
breadth of congressional concern for protection of water quality and 
aquatic ecosystems.'' Id. at 133. It quoted with apparent approval the 
Corps' statement that ``Federal jurisdiction under Section 404 must 
include any adjacent wetlands that form the border of or are in 
reasonable proximity to other waters of the United States, as these 
wetlands are part of this aquatic system.'' Id. at 134 (quoting 42 FR 
37128, July 19, 1977). The Court concluded that ``the Corps' ecological 
judgment about the relationship between waters and their adjacent 
wetlands provides an adequate basis for a legal judgment that adjacent 
wetlands may be defined as waters under the Act.'' Id.
    The Court also viewed the 1977 Act as specifically approving the 
Corps' assertion of jurisdiction over adjacent wetlands--as considering 
those wetlands to be ``waters'' themselves. Id. at 137-139. The Court 
observed that ``the scope of the Corps' asserted jurisdiction over 
wetlands was specifically brought to Congress' attention, and Congress 
rejected measures designed to curb the Corps' jurisdiction in large 
part because of its concern that protection of wetlands would be unduly 
hampered by a narrowed definition of `navigable waters.''' Id. at 137. 
The Court also cited section 404(g)(1) as express textual evidence 
``that the term `waters' included adjacent wetlands.'' Id. at 138.
    Congress had good reason to approve the inclusion of adjacent 
wetlands within the ``waters of the United States.'' In the 1986 
regulations, the agencies determined that wetlands adjacent to 
navigable waters generally play a key role in protecting and enhancing 
water quality, explaining: ``Water moves in hydrologic cycles, and the 
pollution of this part of the aquatic system, regardless of whether it 
is above or below an ordinary high water mark, or mean high tide line, 
will affect the water quality of the other waters within that aquatic 
system. For this reason, the landward limit of Federal jurisdiction 
under Section 404 must include any adjacent wetlands that form the 
border of or are in reasonable proximity to other waters of the United 
States, as these wetlands are part of this aquatic system.'' 42 FR 
37128 (July 19, 1977); see also 38 FR 10834. See section IV.C.8.b of 
this preamble for further discussion of the definition of ``adjacent.''
    As discussed below and further in section III.B of the Technical 
Support Document, the best available science supports the 1986 
regulations' conclusion that adjacent wetlands are part of the aquatic 
ecosystem, and the agencies' construction of the Clean Water Act in 
this rule, that adjacent wetlands that meet the relatively permanent 
standard or the significant nexus standard affect the chemical, 
physical, and biological integrity of paragraph (a)(1) waters by 
performing essential functions, including providing valuable flood 
control and water quality functions such as interruption and delay of 
the transport of water-borne contaminants over long distances, 
retention of sediment, prevention and mitigation of drinking water 
contamination, and assurance of drinking water supply. As Congress 
understood when it rejected efforts to narrow jurisdiction over 
wetlands in

[[Page 3029]]

1977 and the Supreme Court recognized in Riverside Bayview, allowing 
all adjacent wetlands to be filled without any permitting requirements 
would deprive interconnected aquatic systems of those benefits and 
thereby threaten the integrity of traditional navigable waters, the 
territorial seas, and interstate waters. Wetlands are recognized as 
``among the most important ecosystems on Earth.'' \48\ Among many other 
public benefits, wetlands play an ``integral role'' in maintaining the 
nation's ``water supply and quality.'' 16 U.S.C. 3901(a)(1). ``Research 
has demonstrated repeatedly that natural wetlands enhance water 
quality.'' \49\ Through chemical and biological processes, wetlands 
trap and filter sediment, nutrients, and other pollutants that would 
otherwise be carried into downstream waters.\50\ For example, wetlands 
conservation is a crucial feature of the New York City municipal water 
system, which provides high quality drinking water to millions of 
people through watershed protection. New York protects adjacent 
wetlands of its source waters rather than investing in extensive and 
costly treatment. Wetlands also provide ``cost-effective flood 
control,'' \51\ capturing overflow from rivers and streams during times 
of high precipitation or snowmelt.\52\ For example, during Hurricane 
Sandy in 2012, wetlands are estimated to have helped prevent $625 
million in damage by protecting properties from flooding.\53\
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    \48\ William J. Mitsch & James G. Gosselink, Wetlands (5th ed.) 
at 3 (2015).
    \49\ National Research Council, Wetlands: Characteristics and 
Boundaries (``NRC Report'') at 38 (1995).
    \50\ Virginia Carter, ``Wetlands Hydrology, Water Quality, and 
Associated Functions,'' in National Water Summary, supra, at 44-45; 
Science Report at ES-2 to ES-4.
    \51\ Carter, supra note 5050, at 44.
    \52\ See, e.g., NRC Report at 35; Mitsch & Gosselink, supra, at 
539-541; Science Report at ES-2 to ES-4.
    \53\ Narayan, Siddharth, et al. 2017. The Value of Coastal 
Wetlands for Flood Damage Reduction in the Northeastern USA. 
Scientific Reports 7: 9463; Technical Support Document section II.C.
---------------------------------------------------------------------------

iii. It Is Reasonable for the Agencies To Continue To Include a 
Provision To Cover Certain Waters That Do Not Fall Within Other 
Jurisdictional Provisions
    For more than 45 years the agencies' regulations have included a 
provision to address waters that did not fall within the categories it 
established, such as tributaries and adjacent wetlands, because such 
waters could have effects on water quality and on interstate commerce. 
42 FR 37128 (July 19, 1977). This rule substantially revises this 
provision by establishing that intrastate lakes and ponds, streams, or 
wetlands not identified elsewhere in the rule may be determined to be 
``waters of the United States'' if they meet either the relatively 
permanent standard or the significant nexus standard. Therefore, under 
this rule the agencies conclude that it is not appropriate to assert 
jurisdiction over non-navigable, intrastate waters based solely on 
whether the use, degradation, or destruction of the water could affect 
interstate or foreign commerce. See section IV.C.6 of this preamble for 
further discussion of the changes related to this provision. This rule 
replaces the interstate commerce test with the relatively permanent 
standard and the significant nexus standard.
    For more than four decades, the agencies' regulations defining 
``waters of the United States'' have included provisions authorizing 
case-specific determinations of jurisdiction over waters that did not 
fall within the other jurisdictional provisions of the definition. The 
Corps' 1975 interim final regulations addressed both ``intrastate 
lakes, rivers, and streams that are used by interstate recreational 
travelers, for the removal of fish sold in commerce, for interstate 
industrial commercial purposes, or for the production of agricultural 
commodities sold in commerce,'' and ``other waters that the District 
Engineer determines necessitate regulation for protection of water 
quality.'' 40 FR 31320, 31324 (July 25, 1975). As discussed above, 
Congress was well-aware of the scope of the Corps' regulations when 
adopting the 1977 Act.
    The rule properly authorizes case-specific consideration of certain 
waters not covered by the categories established in the rule. As 
discussed below and further in section IV.D of the Technical Support 
Document, the best available science shows that some of these waters--
such as depressional wetlands, open waters, and peatlands--can provide 
important hydrologic (e.g., flood control), water quality, and habitat 
functions which can have effects on larger rivers, lakes, and 
estuaries, including paragraph (a)(1) waters. The functions that 
intrastate lakes and ponds, streams, and wetlands not identified in 
paragraphs (a)(1) through (4) of this rule (i.e., paragraph (a)(5) 
waters) can provide to paragraph (a)(1) waters include storage of 
floodwater, recharge of ground water that sustains river baseflow, 
retention and transformation of nutrients, metals, and pesticides, 
export of organisms to paragraph (a)(1) waters, and habitats needed for 
aquatic and semi-aquatic species that also utilize paragraph (a)(1) 
waters. In addition, the agencies have never stated that the waterbody-
specific categories alone identify every jurisdictional water under the 
Clean Water Act because in an area as vast and varied as the United 
States, it is not possible to create an exhaustive list of waters that 
provide these critical functions to paragraph (a)(1) waters. Indeed, a 
clear example of waters that do not fall within any of the categories 
are some lakes and ponds near jurisdictional tributaries or paragraph 
(a)(1) waters. They are not wetlands (so do not fall within the 
adjacent wetlands category), and many are not tributaries, but they are 
very likely to meet either the relatively permanent standard or the 
significant nexus standard. A lake that is not a tributary and is not a 
wetland may have a continuous surface connection to a traditional 
navigable water. It would not make sense to exclude such a lake from 
jurisdiction as it would have many of the same effects on the 
traditional navigable water as an adjacent wetland with the same 
continuous surface connection. Likewise, a lake that is not a tributary 
and is not a wetland may be near a jurisdictional tributary and 
significantly affect a paragraph (a)(1) water by providing similar 
functions as an adjacent wetland. Absent paragraph (a)(5) of this rule, 
these lakes would meet either the relatively permanent standard or the 
significant nexus standard, but would not fall within any of the 
categories of waters established by the definition. Thus, where waters 
do not fall within one of the more specific categories identified in 
paragraph (a)(1) through (4) of this rule, the rule provides for such 
waters to be evaluated for jurisdiction under paragraph (a)(5) and to 
be jurisdictional if they meet either standard.
c. The Best Available Science Demonstrates That This Rule Properly 
Advances the Objective of the Clean Water Act
    This rule is informed by the best available science on the 
functions provided by waters, including wetlands, that are important 
for the chemical, physical, or biological integrity of traditional 
navigable waters, the territorial seas, and interstate waters. The 
scientific literature extensively illustrates the effects tributaries, 
adjacent wetlands, as well as intrastate lakes and ponds, streams, and 
wetlands can and do have on the integrity of traditional navigable 
waters, the territorial seas, and interstate waters. The relevant 
science on the relationship and effects of streams, wetlands, and open 
waters (such as lakes and ponds)

[[Page 3030]]

on larger downstream waters has continued to advance in recent years 
and confirms the agencies' longstanding view that these waters should 
be assessed for jurisdiction under the Clean Water Act. The Science 
Report synthesized the peer-reviewed science regarding connectivity and 
effects of streams, wetlands, and open waters to larger downstream 
waters. Since the release of the Science Report, additional published 
peer-reviewed scientific literature has strengthened and supplemented 
the report's conclusions. The agencies have summarized and provided an 
update on more recent literature and scientific support for this 
section in the Technical Support Document section I.C. See also 
Technical Support Document section III. This section summarizes the 
best available science in support of the longstanding categories of the 
1986 regulation, and in support of this rule and the agencies' 
conclusion that this rule advances the objective of the Clean Water 
Act. This section reflects the scientific consensus on the strength of 
the effects that tributaries, adjacent wetlands, and paragraph (a)(5) 
waters can and do have on traditional navigable waters, the territorial 
seas, and interstate waters. Note that for purposes of this final rule, 
the agencies have not made a categorical determination that all 
tributaries, adjacent wetlands, and paragraph (a)(5) waters 
significantly affect paragraph (a)(1) waters. See section IV.A.3.a.iii 
(discussing the final rule's reliance on a case-specific approach to 
assessing jurisdiction for certain types of waters) of this preamble.
    As the agencies charged with construing the statute, EPA and the 
Corps must develop the outer bounds of the scope of the Clean Water 
Act. Congress chose to delegate this authority to the expert agency 
focused on environmental protection and, for the section 404 program, 
to the agency with extensive permitting experience for discharges to 
water. In section 501(a) of the Clean Water Act, Congress explicitly 
delegated regulatory authority to EPA: ``The Administrator is 
authorized to prescribe such regulations as are necessary to carry out 
his functions under this Act.'' The Supreme Court in Riverside Bayview 
recognized this decision by Congress and deferred to the agencies' 
scientific expertise and judgement, finding that ``[i]n view of the 
breadth of federal regulatory authority contemplated by the Act itself 
and the inherent difficulties of defining precise bounds to regulable 
waters, the Corps' ecological judgment about the relationship between 
waters and their adjacent wetlands provides an adequate basis for a 
legal judgment that adjacent wetlands may be defined as waters under 
the Act.'' 474 U.S. at 134. Science alone cannot dictate where to draw 
the line defining ``waters of the United States,'' but science is 
critical to understanding what scope of jurisdiction furthers 
Congress's objective to restore and maintain the chemical, physical, 
and biological integrity of the nation's waters: only by relying upon 
scientific principles to understand the way waters affect one another 
can the agencies know whether they are achieving that objective. 
Because the definition of ``waters of the United States'' should 
advance the objective of the Clean Water Act and that objective is 
focused on restoring and maintaining water quality, the best available 
science informs this rule. See section IV.A.2 of this preamble; see 
also section IV.B.3 of this preamble for the agencies' conclusion that 
the 2020 NWPR was inconsistent with the best available science in 
important ways.
i. Tributaries Can Provide Functions That Restore and Maintain the 
Chemical, Physical, and Biological Integrity of Downstream Traditional 
Navigable Waters, the Territorial Seas, and Interstate Waters
    Tributaries play an important role in the transport of water, 
sediments, organic matter, nutrients, and organisms to downstream 
paragraph (a)(1) waters. See Technical Support Document section III.A. 
Tributaries slow and attenuate floodwaters; provide functions that help 
maintain water quality; trap and transport sediments; transport, store, 
and modify pollutants; and sustain the biological productivity of 
downstream paragraph (a)(1) waters. Indeed, the Supreme Court has 
recognized the importance of the physical integrity of upstream 
tributaries in overcoming sedimentation hazards to navigation. United 
States v. Rio Grande Dam & Irrigation Co., 174 U.S. 690 (1899). 
Tributaries can provide these functions whether they are natural, 
modified, or constructed and regardless of their flow regime.
    All tributary streams, including perennial, intermittent, and 
ephemeral streams, are chemically, physically, and biologically 
connected to larger downstream waters via channels and associated 
alluvial deposits where water and other materials are concentrated, 
mixed, transformed, and transported. The agencies note that while the 
Science Report concluded such tributary streams were so connected, the 
significant nexus standard is distinct from this scientific conclusion, 
and the agencies are not in this rule concluding that all tributary 
streams categorically meet the significant nexus standard. Streams, 
even where seasonally dry, are the dominant source of water in most 
rivers, rather than direct precipitation or groundwater input to 
mainstem river segments. Within stream and river networks, headwater 
streams make up most of the total channel length. The smallest streams 
represent an estimated three-quarters of the total length of stream and 
river channels in the United States.\54\ Because of their abundance and 
location in the watershed, small streams offer the greatest opportunity 
for exchange between the water and the terrestrial environment.
---------------------------------------------------------------------------

    \54\ The actual proportion may be much higher because this 
estimate is based on the stream networks shown on the U.S. 
Geological Survey (USGS) National Hydrography Dataset, which does 
not show all headwater streams.
---------------------------------------------------------------------------

    In addition, compared with the humid regions of the country, stream 
and river networks in arid regions have a higher proportion of channels 
that do not flow perennially. For example, in Arizona, most of the 
stream channels--96% by length--are classified as ephemeral or 
intermittent. The functions that streams provide to benefit downstream 
waters occur even when streams do not flow constantly. For example, 
ephemeral headwater streams shape larger downstream river channels by 
accumulating and gradually or episodically releasing stored materials 
such as sediment and large woody debris.\55\ Due to the episodic nature 
of flow in ephemeral and intermittent channels, sediment and organic 
matter can be deposited some distance downstream in the arid Southwest 
in particular, and then moved farther downstream by subsequent 
precipitation events. Over time, sediment and organic matter continue 
to move downstream and influence larger downstream waters. These 
materials help structure downstream river channels by slowing the flow 
of water

[[Page 3031]]

through channels and providing substrate and habitat for aquatic 
organisms.
---------------------------------------------------------------------------

    \55\ Videos of ephemeral streams flowing after rain events in 
the Southwest highlight how effective ephemeral streams can be in 
transporting woody debris (e.g., tree branches) and sediment 
downstream during the rainy season. See, e.g., U.S. Department of 
Agriculture, Agricultural Research Service, Multiflume Runoff Event 
August 1, 1990, https://www.tucson.ars.ag.gov/unit/WGWebcam/WalnutGulchWebcam.htm; U.S. Geological Survey, Post-fire Flash Flood 
in Coronado National Memorial, Arizona (August 25, 2011), https://www.youtube.com/watch?v=qJ8JxBZt6Ws; Santa Clara Pueblo Fire/Rescue/
EMS Volunteer Department, Greg Lonewolf, #4 Santa Clara Pueblo Flash 
Flood Event 01 Sept 2013 (April 14, 2017), https://www.youtube.com/watch?v=nKOQzkRi4BQ; Rankin Studio, Amazing Flash Flood/Debris Flow 
Southern Utah HD (July 19, 2019), https://www.youtube.com/watch?v=_yCnQuILmsM.
---------------------------------------------------------------------------

    Stream and wetland ecosystems also process natural and human 
sources of nutrients, such as those found in leaves that fall into 
streams and those that may flow into creeks from agricultural fields. 
Some of this processing converts the nutrients into more biologically 
useful forms. Other aspects of the processing store nutrients, thereby 
allowing their slow and steady release and preventing the kind of 
short-term glut of nutrients that can cause algal blooms in downstream 
rivers or lakes. Small streams and their associated wetlands play a key 
role in both storing and modifying potential pollutants, ranging from 
chemical fertilizers to rotting salmon carcasses, in ways that maintain 
downstream water quality. Inorganic nitrogen and phosphorus, the main 
chemicals in agricultural fertilizers, are essential nutrients not just 
for plants, but for all living organisms. However, in excess or in the 
wrong proportions, these chemicals can harm natural systems and humans. 
Larger rivers process excess nutrients much more slowly than smaller 
streams. Loss of nutrient retention capacity in headwater streams is 
known to cause higher concentrations and loads of nitrogen and 
phosphorus in downstream waterbodies. In freshwater ecosystems, 
eutrophication, the enriching of waters by excess nitrogen and 
phosphorus, sets off a chain reaction of events that reduces water 
quality in streams, lakes, estuaries, and other downstream waterbodies. 
The excess nutrients lead to the overabundance of algae and aquatic 
plants. Too much algae clouds previously clear streams, such as those 
favored by trout. Algal blooms not only reduce water column visibility, 
but the microbial decay of algal blooms reduces the amount of oxygen 
dissolved in the water, and therefore the amount available to aquatic 
life, sometimes to a degree that causes fish kills. Fish are not the 
only organisms harmed by eutrophication: some of the algae species that 
grow in eutrophic waters generate tastes and odors or are toxic--a 
clear problem for stream systems, reservoirs, and lakes that supply 
drinking water for municipalities or that are used for swimming and 
other contact-recreational purposes. Algal blooms driven by excess 
nutrients also can injure people and animals, as toxins can kill native 
fish and other wildlife, and endanger human health. Algal blooms can 
also lead to beach closures. The overabundance of plant growth and 
alterations in water chemistry that occur in eutrophic waters also 
changes the composition of natural communities of aquatic ecosystems.
    Recycling organic carbon contained in dead plants and animals is 
another crucial function provided by headwater streams and wetlands. 
Ecological processes that transform inorganic carbon into organic 
carbon and recycle organic carbon are the basis for every food web on 
the planet. In freshwater ecosystems, much of the recycling happens in 
small streams and wetlands, where microorganisms transform everything 
from leaf litter and downed logs to dead salamanders into food for 
other organisms in the aquatic food web. Like nitrogen and phosphorus, 
carbon is essential to life but can be harmful to freshwater ecosystems 
if it is present in excess or in the wrong chemical form. If all 
organic material received by headwater streams and wetlands went 
directly downstream, the glut of decomposing material could deplete 
oxygen in downstream rivers, thereby damaging and even killing fish and 
other aquatic life. The ability of headwater stream ecosystems to 
transform organic matter into more usable forms helps maintain healthy 
downstream ecosystems.
    Microorganisms in headwater stream systems use leaf litter and 
other decomposing matter for food and, in turn, become food for other 
organisms. For example, fungi that grow on leaf litter become 
nutritious food for aquatic insects that make their homes on the bottom 
of streams, including mayflies, stoneflies, and caddisflies. These 
animals provide food for larger animals, including birds such as 
flycatchers and fish such as trout. The health and productivity of 
downstream traditional navigable waters, the territorial seas, and 
interstate waters depend in part on processed organic carbon delivered 
by upstream headwater systems.
    To be clear, the agencies recognize that SWANCC held that the use 
of an abandoned sand and gravel pit by migratory birds was not by 
itself a sufficient basis for the exercise of Federal regulatory 
authority under the Clean Water Act. Consideration of biological 
functions does not constitute an assertion of jurisdiction over a water 
based solely on its use by migratory birds. Rather, the agencies 
consider biological functions for purposes of significant nexus 
determinations under this rule only to the extent that the functions 
provided by tributaries, adjacent wetlands, and paragraph (a)(5) waters 
significantly affect the biological integrity of the traditional 
navigable waters, the territorial seas, or interstate waters. For 
example, salmon are a critical component of the biological integrity in 
certain paragraph (a)(1) waters, and they provide one of the clearest 
illustrations of biological connectivity. To protect Pacific and 
Atlantic salmon in traditional navigable waters (and their associated 
commercial and recreational fishing industries), headwater streams must 
be protected because Pacific and Atlantic salmon require both 
freshwater and marine habitats over their life cycles and therefore 
migrate along river networks. Many Pacific salmon species spawn in 
headwater streams, where their young grow for a year or more before 
migrating downstream, live their adult life stages in the ocean, and 
then migrate back upstream to spawn. Even where they do not provide 
direct habitat for salmon themselves, ephemeral streams may contribute 
to the habitat needs of salmon by supplying sources of cold water that 
these species need to survive (i.e., by providing appropriate physical 
conditions for cold water upwelling to occur at downstream 
confluences), transporting sediment that supports fish habitat 
downstream, and providing and transporting food for juveniles and 
adults downstream. These species thereby create a biological connection 
along the entire length of the river network, demonstrating how the 
upstream ephemeral waters can help to maintain the biological integrity 
of the downstream traditional navigable water. Many other species of 
anadromous fish (fish that are born in freshwater, spend most of their 
lives in saltwater, and return to freshwater to spawn) like certain 
lamprey, species of catadromous fish (fish that breed in the ocean but 
that spend most of their lives in freshwater) like American eels, and 
freshwater fish like rainbow trout and brook trout also require small 
headwater streams to carry out life cycle functions. See Technical 
Support Document sections III.A.iii and III.E.iv.
ii. Adjacent Wetlands Can Provide Functions That Restore and Maintain 
the Chemical, Physical, and Biological Integrity of Traditional 
Navigable Waters, the Territorial Seas, and Interstate Waters
    Adjacent wetlands provide valuable flood control and water quality 
functions that affect the chemical, physical, and biological integrity 
of paragraph (a)(1) waters including interruption and delay of the 
transport of water-borne contaminants over long distances; retention of 
sediment; retention and slow release of flood waters; and prevention 
and mitigation of drinking water contamination and assurance of 
drinking water supply. See

[[Page 3032]]

Technical Support Document section III.B. The agencies note that, while 
the Science Report concluded such adjacent wetlands were so connected, 
the significant nexus standard is distinct from this scientific 
conclusion, and the agencies are not concluding in this rule that all 
adjacent wetlands categorically meet the significant nexus standard.
    Because adjacent wetlands retain sediment and augment streamflow 
via the gradual release of groundwater, stormwater, or water flowing 
just beneath the soil surface, wetland loss correlates with increased 
need for dredging and unpredictability of adequate streamflow for 
navigation. Headwater wetlands are located where erosion risk is 
highest and are therefore best suited to recapture and stabilize 
manageable amounts of sediment that might enter traditional navigable 
waters, the territorial seas, or interstate waters. Adjacent wetlands 
naturally serve to recapture and stabilize sediment carried by streams 
and rivers in times when flood flow distributes water across a 
floodplain.
    Adjacent wetlands affect the integrity of paragraph (a)(1) waters 
by retaining stormwater and slowly releasing floodwaters that could 
otherwise negatively affect the condition or function of those 
paragraph (a)(1) waters. The filling or draining of wetlands, including 
those that are close to the stream network, reduces water storage 
capacity in a watershed and causes runoff from rainstorms to overwhelm 
the remaining available water conveyance system. The resulting stream 
erosion and channel downcutting impair water quality and quickly drain 
the watershed as surface water leaves via incised (deeper) channels. 
Disconnecting the incised channel from the wetlands leads to more 
downstream flooding. As the adjacent wetlands remain disconnected, 
riparian vegetation and wetland functions are reduced. Moreover, 
because less water is available in groundwater and wetlands for slow 
release to augment streamflow during dry periods, the filling or 
draining of wetlands can make the timing and extent of navigability on 
some waterways less predictable during dry periods. Therefore, intact 
adjacent wetlands, including headwater wetlands, can contribute to 
maintaining navigability on the nation's rivers and harbors and can 
reduce flooding in paragraph (a)(1) waters.
    Wetlands adjacent to tributaries of navigable waters, the 
territorial seas, and interstate waters can also help promote 
improvements in drinking water supply and quality. Over 228 million 
people are served by nearly 15,000 public water systems using surface 
water such as streams, rivers, lakes, tributaries, and surface-water 
storage impoundments as a primary source of water.\56\ An estimated 61% 
of water withdrawn for public water supply came from surface water 
sources in 2015.\57\ Adjacent wetlands have an important role in 
mitigating the risk of contamination to sources of drinking water, and 
in water quality generally, due to their strategic location as buffers 
for other waterbodies and their filtration of surface water. Retention 
of water and its associated constituents by wetlands allows the 
biochemical uptake and/or breakdown of contaminants and the destruction 
of pathogens. The water retention capacity of adjacent wetlands also 
allows for the storage and gradual release of surface waters that may 
supply public water system intakes during times of drought. In either 
case, this retention substantially improves both the supply and quality 
of drinking water.
---------------------------------------------------------------------------

    \56\ EPA data from 2022 Third Quarter Safe Drinking Water 
Information System/Federal Version.
    \57\ Comments submitted by Association of Metropolitan Water 
Agencies at 2 (February 4, 2022) (Docket ID No. EPA-HQ-OW-2021-0602-
0252), https://www.regulations.gov/comment/EPA-HQ-OW-2021-0602-0252 
(citing Dieter, C.A., Maupin, M.A., Caldwell, R.R., Harris, M.A., 
Ivahnenko, T.I., Lovelace, J.K., Barber, N.L., and Linsey, K.S., 
2018, Estimated use of water in the United States in 2015: U.S. 
Geological Survey Circular 1441. Retrieved from https://pubs.usgs.gov/circ/1441/circ1441.pdf).
---------------------------------------------------------------------------

    Though drinking water supplied through public water supplies is 
regulated by the Safe Drinking Water Act, many water suppliers also 
rely on source water protection efforts under the Clean Water Act, as 
the quality of the drinking water source is dependent on the protection 
of its upstream waters. Conserving wetlands in source water protection 
areas can help protect water quality, recharge aquifers, and maintain 
surface water flow during dry periods. For example, wetlands 
conservation is a crucial feature of the low-cost New York City 
municipal water system, which provides high-quality drinking water to 
millions of people through watershed protection, including of adjacent 
wetlands, of its source waters rather than extensive treatment.
    Discharge of agricultural, industrial, sanitary, or other waste 
into any surface water may pose a public health risk downstream. For 
example, excessive upstream discharge may overwhelm a public water 
system filtration unit, allowing microbial pathogens into the drinking 
water system. EPA's Science Advisory Board cited drinking water 
contamination by pathogens as one of the most important environmental 
risks.\58\ Moreover, drinking water treatment to address microbial 
pathogens has little effect on many toxic chemicals, metals, and 
pesticides discharged into streams, drainage ditches, canals, or other 
surface waters.
---------------------------------------------------------------------------

    \58\ U.S. Environmental Protection Agency/Science Advisory 
Board. 1990. Reducing Risk: Setting Priorities and Strategies for 
Environmental Protection. SAB-EC-90-021. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=2000PNG1.TXT.
---------------------------------------------------------------------------

    In sum, adjacent wetlands can provide a variety of functions to 
paragraph (a)(1) waters. Based on the importance of these functions to 
paragraph (a)(1) waters, the agencies' interpretation of the Clean 
Water Act to protect adjacent wetlands where those adjacent wetlands 
meet either the relatively permanent standard or the significant nexus 
standard reflects proper consideration of the objective of the Act and 
the best available science.
iii. Intrastate Lakes and Ponds, Streams, or Wetlands Not Identified in 
Paragraphs (a)(1) Through (4) of This Rule Can Provide Functions That 
Restore and Maintain the Chemical, Physical, and Biological Integrity 
of Traditional Navigable Waters, the Territorial Seas, and Interstate 
Waters
    Intrastate lakes and ponds, streams, or wetlands not identified in 
paragraphs (a)(1) through (4) of the rule--examples of which could 
include, but are not limited to, prairie potholes, playa lakes, and 
vernal pools--can provide important functions that affect the chemical, 
physical, and biological integrity of paragraph (a)(1) waters. See 
Technical Support Document section III.D. The agencies note that while 
the Science Report concluded such intrastate lakes and ponds, streams, 
and wetlands can provide these functions, the significant nexus 
standard is distinct from this scientific conclusion, and the agencies 
are not concluding in this rule that all intrastate lakes and ponds, 
streams, and wetlands categorically meet the significant nexus 
standard. These functions are particularly valuable when considered 
cumulatively across the landscape or across different watershed or sub-
watershed scales. They are similar to the functions that adjacent 
wetlands provide, including water storage to control streamflow and 
mitigate downstream flooding; interruption and delay of the transport 
of water-borne pollutants (such as excess nutrients and contaminants) 
over long distances; and retention of sediment. These functions can be 
important to the physical integrity of paragraph (a)(1) waters. For 
non-

[[Page 3033]]

floodplain wetlands and open waters lacking a channelized surface or 
regular shallow subsurface connection, generalizations from the 
available literature about their specific effects on downstream waters 
are difficult because information on both function and connectivity is 
needed. Accordingly, a case-specific analysis of their effects on 
paragraph (a)(1) waters is appropriate from both a scientific and 
policy perspective.
    For example, oxbow lakes and other lakes and ponds that are in 
close proximity to the stream network, that are located within 
floodplain or riparian areas, or that are connected via surface and 
shallow subsurface hydrology to the stream network or to other ``waters 
of the United States'' perform critical chemical, physical, and 
biological functions that affect paragraph (a)(1) waters. Like adjacent 
wetlands, these waters individually and collectively affect the 
integrity of paragraph (a)(1) waters by acting as sinks that retain 
floodwaters, sediments, nutrients, and contaminants that could 
otherwise negatively impact the condition or function of those 
paragraph (a)(1) waters. They also provide important habitat for 
aquatic species that utilize both the lake and pond and the nearby 
paragraph (a)(1) water to forage, breed, and rest.
    Intrastate lakes and ponds, streams, and wetlands not identified in 
paragraphs (a)(1) through (4) of the rule span the gradient of 
connectivity identified in the Science Report. They can be open waters 
located in the riparian area or floodplain of traditional navigable 
waters, the territorial seas, and interstate waters (e.g., oxbow lakes) 
and otherwise be physically proximate to the stream network (similar to 
adjacent wetlands) or they can be open waters or wetlands that are 
fairly distant from the network. They can also be connected to 
paragraph (a)(1) waters through biological connections, such as through 
the movement of aquatic and semi-aquatic species for habitat or other 
lifecycle needs and can serve as sources of food for larger aquatic and 
semi-aquatic animals that live in paragraph (a)(1) waters. See section 
III.D of the Technical Support Document. These waters can also provide 
additional functions such as storage and mitigation of peak flows, 
natural filtration by biochemical uptake and/or breakdown of 
contaminants, and, in some locations, high volume aquifer recharge that 
contributes to the baseflow in paragraph (a)(1) waters. The strength of 
functions provided by intrastate lakes and ponds, streams, and wetlands 
that are evaluated under paragraph (a)(5) on paragraph (a)(1) waters 
will vary depending on the type and degree of connection (i.e., from 
highly connected to highly isolated) to paragraph (a)(1) waters and 
landscape features such as proximity to stream networks and to such 
waters with similar characteristics that function together to influence 
paragraph (a)(1) waters.
    Since the publication of the Science Report in 2015, the published 
literature has expanded scientific understanding and quantification of 
the functions of these waters that affect the integrity of larger 
waters, including traditional navigable waters, the territorial seas, 
and interstate waters, particularly in the aggregate. More recent 
literature (i.e., 2014-present, as some literature from 2014 and 2015 
may not have been included in the Science Report) has determined that 
non-floodplain wetlands can have demonstrable hydrologic and 
biogeochemical downstream effects, such as decreasing peak flows, 
maintaining baseflows, and performing nitrate removal, particularly 
when considered cumulatively.
    Some intrastate lakes and ponds, streams, and wetlands not 
identified in paragraphs (a)(1) through (4) can, in certain 
circumstances, have strong chemical, physical, or biological 
connections to and effects on paragraph (a)(1) waters. However, some 
intrastate lakes and ponds, streams, and wetlands not identified in 
paragraphs (a)(1) through (4) of this rule do not have significant 
effects on paragraph (a)(1) waters because of their distance from 
paragraph (a)(1) waters, their landscape position, climatological 
variables, or other factors. The effect of distance on a significant 
nexus analysis, for example, may vary based on the characteristics of 
the aquatic resources being evaluated and other factors affecting the 
strength of their connectivity to paragraph (a)(1) waters. Waters are 
less likely to have a significant nexus if they are located outside of 
the riparian area or floodplain, lack a confined surface or shallow 
subsurface hydrologic connection to jurisdictional waters, or exceed 
the minimum distances necessary for aquatic species that cannot 
disperse overland to utilize both the subject waters \59\ and the 
waters in the broader tributary network. However, sometimes it is their 
lack of a hydrologic surface connection that contributes to the 
important effect that they have on paragraph (a)(1) waters; for 
example, depressional non-floodplain wetlands lacking surface outlets 
can function individually and cumulatively to retain and transform 
nutrients, retain sediment, provide habitat, and reduce or attenuate 
downstream flooding, depending on site-specific conditions such as 
landscape characteristics (e.g., slope of the terrain or permeability 
of the soils). Justice Kennedy's insight that ``[g]iven the role 
wetlands play in pollutant filtering, flood control, and runoff 
storage, it may well be the absence of hydrologic connection (in the 
sense of interchange of waters) that shows the wetlands' significance 
for the aquatic system'' is consistent with the science. See Rapanos, 
547 U.S. at 786 (Kennedy, J., concurring in the judgment).
---------------------------------------------------------------------------

    \59\ In this preamble, the agencies use ``subject waters'' to 
mean the water or waters being assessed for jurisdiction. ``Subject 
waters evaluated pursuant to the significant nexus standard'' means 
the water either alone or in combination with similarly situated 
waters in the region.
---------------------------------------------------------------------------

    Based on the functions that can be provided by intrastate lakes and 
ponds, streams, and wetlands not identified in paragraphs (a)(1) 
through (4) to traditional navigable waters, the territorial seas, and 
interstate waters, assessing these waters to determine whether they 
meet either the relatively permanent standard or the significant nexus 
standard reflects proper consideration of the objective of the Clean 
Water Act and the best available science.
3. The Scope of This Rule Is Limited Consistent With the Law, the 
Science, and Agency Expertise
    In this rule, the agencies are exercising their authority to 
construe ``waters of the United States'' to mean the waters defined by 
the familiar 1986 regulations with amendments to reflect the agencies' 
interpretation of the statutory limits on the scope of the ``waters of 
the United States.'' This construction is supported by consideration of 
the text of the relevant provisions of the Clean Water Act and the 
statute as a whole, the scientific record, relevant Supreme Court 
decisions, and the agencies' experience and technical expertise after 
more than 45 years of implementing the longstanding pre-2015 
regulations defining ``waters of the United States.'' This rule's 
limitations are based on the agencies' conclusion that the significant 
nexus standard is consistent with the statutory text and legislative 
history, advances the objective of the Clean Water Act, is informed by 
the scientific record and Supreme Court case law, and appropriately 
considers the policies of the Act. The agencies have also determined 
that the relatively permanent standard should be included in the rule 
because, while it identifies only a subset of the ``waters of the

[[Page 3034]]

United States,'' it provides important efficiencies and additional 
clarity for regulators and the public.
    This section of the preamble first explains the agencies' 
conclusion that utilization of both the relatively permanent standard 
and the significant nexus standard gives effect to the Clean Water 
Act's text, including its objective as well as its limitations. The 
significant nexus standard is consistent with the text, objective, and 
legislative history of the Clean Water Act, as well as relevant Supreme 
Court case law and the best available science. The relatively permanent 
standard is administratively useful as it more readily identifies a 
subset of waters that will virtually always significantly affect 
paragraph (a)(1) waters, but standing alone the standard is 
insufficient to meet the objective of the Clean Water Act. This section 
also explains that fact-based standards for determining Clean Water Act 
jurisdiction are appropriate and not unusual under the Act. The 
agencies have the discretion to consider defining waters as 
jurisdictional on a categorical basis where scientifically and legally 
justified (for example in this rule, paragraph (a)(1) waters and their 
adjacent wetlands) or on a case-specific, fact-based approach (for 
example, in this rule, tributaries and their adjacent wetlands that 
meet the relatively permanent standard or significant nexus standard). 
Finally, this section explains how this rule reflects full and proper 
consideration of the water quality objective in section 101(a) and the 
policies relating to responsibilities and rights of Tribes and States 
under section 101(b) of the Clean Water Act. Based on these 
considerations, the agencies have concluded that the significant nexus 
standard in this rule is the best interpretation of section 502(7) of 
the Act.
a. The Limitations Established by This Rule Advance the Objective of 
the Clean Water Act
    This rule's utilization of both the relatively permanent standard 
and the significant nexus standard gives effect to the Clean Water 
Act's text and environmentally protective objective as well as its 
limitations. See Rapanos, 547 U.S. at 767-69 (Kennedy, J., concurring 
in the judgment) (observing ``the evident breadth of congressional 
concern for protection of water quality and aquatic ecosystems'' and 
referring to the Clean Water Act as ``a statute concerned with 
downstream water quality'' (citations omitted)); Riverside Bayview, 474 
U.S. at 133 (``Congress chose to define the waters covered by the Act 
broadly.''). The agencies, however, have concluded that it is the 
significant nexus standard that advances the objective of the Clean 
Water Act because it is linked to effects on the water quality of 
paragraph (a)(1) waters while also establishing an appropriate 
limitation on the scope of jurisdiction by requiring that those effects 
be significant. The relatively permanent standard is administratively 
useful as it more readily identifies a subset of waters that will 
virtually always significantly affect paragraph (a)(1) waters, but, 
exclusive reliance on the standard for all determinations is 
inconsistent with the text of the statute and Supreme Court precedent 
and is insufficient to advance the objective of the Clean Water Act.
    With this rule, the agencies conclude that if a water meets either 
the relatively permanent standard or the significant nexus standard, it 
falls within the protections established by the Clean Water Act. As 
discussed earlier, this rule is not based on an application of the 
Marks test for interpreting Supreme Court decisions; rather, with this 
rule, the agencies are interpreting the scope of the definition of 
``navigable waters,'' informed by relevant Supreme Court precedent, but 
also based on the text of the relevant provisions of the Clean Water 
Act and the statute as a whole, the scientific record, and the 
agencies' experience and technical expertise after more than 45 years 
of implementing the longstanding pre-2015 regulations defining ``waters 
of the United States.''
    This section first discusses why the significant nexus standard is 
consistent with the text, objective, and legislative history of the 
Clean Water Act, as well as relevant Supreme Court case law and the 
best available science; then explains why the relatively permanent 
standard is administratively useful but on its own is insufficient; 
and, finally, explains that fact-based standards for determining Clean 
Water Act jurisdiction are appropriate and not unique to the definition 
of ``waters of the United States.''
i. The Significant Nexus Standard Is Consistent With the Text and 
Objective of the Clean Water Act, Legislative History, Case Law, and 
the Best Available Science
    The significant nexus standard, as the agencies have established it 
in this rule, is the best interpretation of the Clean Water Act because 
it is consistent with the text, including the Act's statutory objective 
and statutory structure, the legislative history and case law, and is 
supported by the best available science. The standard is consistent 
with the plain language of the Act's objective because it is based upon 
effects on the water quality of paragraph (a)(1) waters and limits the 
scope of jurisdiction based on the text of that objective. Moreover, 
protection of waters that significantly affect the paragraph (a)(1) 
waters--i.e., traditional navigable waters, the territorial seas, and 
interstate waters--is consistent with the scope of Commerce Clause 
authority that the Supreme Court in SWANCC concluded that Congress was 
exercising, while also fulfilling Congress's intent in exercising that 
authority in enacting the Clean Water Act.
    The significant nexus standard effectuates the text of Clean Water 
Act section 502(7), which defines ``navigable waters'' as ``the waters 
of the United States, including the territorial seas.'' The standard is 
properly focused on protecting paragraph (a)(1) waters, which are the 
foundation of the Clean Water Act: traditional navigable waters (which 
``navigable waters'' clearly invokes but is not limited to); ``the 
territorial seas'' (which are explicitly listed in section 502(7)); and 
interstate waters (which are unambiguously waters ``of the United 
States,'' as they are waters of the ``several States,'' U.S. Const. 
section 8). Further, each of the rule's provisions identifies an 
aquatic resource that meets the definition of ``water'' or ``waters'' 
in either the Rapanos plurality's preferred dictionary or the 
dictionary most contemporaneous with the passage of the Clean Water 
Act. See section IV.A.3.a.ii of this preamble for discussion of the 
plurality's dictionary-based analysis. The first definition of 
``water'' within Webster's Second (1.a. of the definition) is ``[t]he 
liquid which descends from the clouds in rain and which forms rivers, 
lakes, seas, etc.,'' Webster's New International Dictionary 2882 (2d 
ed. 1954). The definition of ``waters,'' plural, in the most 
contemporaneous Webster's, is: ``the water occupying or flowing in a 
particular bed.'' Webster's Third New Intl. (1966). Even the Rapanos 
plurality's preferred definition includes ``water as found in 
`streams,' '' ``water `[a]s found in streams and bodies forming 
geographical features such as oceans, rivers, [and] lakes,' or `the 
flowing or moving masses, as of waves or floods, making up such streams 
or bodies.' '' Rapanos, 547 U.S. at 732-33 (quoting Webster's New 
International Dictionary 2882, definition 2.c). Traditional navigable 
waters; interstate waters; the territorial seas; impoundments of 
waters; tributaries; adjacent wetlands; and intrastate lakes and ponds, 
streams, and wetlands are ``water'' or ``waters'' under these 
definitions, as identified by hydrologists

[[Page 3035]]

and other scientists, and in practice. Moreover, with respect to 
whether wetlands are waters, that question has already been resolved by 
both science and a unanimous Supreme Court in Riverside Bayview. 474 
U.S. at 137-39. The requirement that a significant nexus exist between 
upstream waters, including wetlands, and ``navigable waters in the 
traditional sense'' thus clearly advances Congress's stated objective 
in the Act while fulfilling ``the need to give the term `navigable' 
some meaning.'' Rapanos, 547 U.S. at 779 (Kennedy, J., concurring in 
the judgment). See also section IV.C.2.b.iii of this preamble for 
discussion of the Clean Water Act's jurisdiction over interstate 
waters. Finally, the text and focus of the rule's significant nexus 
standard are derived from and designed to advance the text of the first 
sentence in the statute setting forth the Act's sole statutory 
objective: ``to restore and maintain the chemical, physical, and 
biological integrity of the Nation's waters.'' See 33 U.S.C. 1251(a).
    As noted above, a statute must be interpreted in light of the 
purposes Congress sought to achieve. See, e.g., Gen. Dynamics Land 
Sys., Inc. v. Cline, 540 U.S. 581 (2004). Thus, the agencies must 
consider the objective of the Clean Water Act to ``restore and maintain 
the chemical, physical, and biological integrity of the Nation's 
waters'' in interpreting the scope of the statutory term ``waters of 
the United States.'' See 33 U.S.C. 1251(a). This consideration is 
particularly important where, as here, Congress used specific language 
in the definitions in order to meet the objective of the Act and the 
definition of ``waters of the United States'' is fundamental to meeting 
the objective of the Act. See section IV.A.2 of this preamble. Congress 
was focused on water quality when it enacted the Clean Water Act and 
established the Act's objective, and the significant nexus standard is 
derived from the objective of the Act to protect the water quality of 
the paragraph (a)(1) waters. The significant nexus standard is 
consistent with foundational scientific understanding about aquatic 
ecosystems: waters can significantly affect the chemical, physical, and 
biological integrity of traditional navigable waters, the territorial 
seas, and interstate waters. Therefore, assessing the effects that 
waters have on paragraph (a)(1) waters when considered, alone or in 
combination with other similarly situated waters in a region, is the 
best means of identifying those waters that must be protected in order 
to advance the objective of the Clean Water Act.
    The agencies have also considered the statute as a whole in 
construing the scope of ``waters of the United States.'' The 
comprehensive nature of the Clean Water Act and its pronounced change 
in approach from precursor water protection statutes is evident 
throughout the statute, and the agencies have considered the text of 
those provisions in defining ``waters of the United States.'' One of 
the Clean Water Act's principal tools in protecting the integrity of 
the nation's waters is section 301(a), which prohibits ``the discharge 
of any pollutant by any person'' without a permit or other 
authorization under the Act. Other substantive provisions of the Clean 
Water Act that use the term ``navigable waters'' and are designed to 
meet the statutory objective include the section 402 permit program, 
the section 404 dredged and fill permit program, the section 311 oil 
spill prevention and response program, the section 303 water quality 
standards and total maximum daily load programs, and the section 401 
Tribal and State water quality certification process. Each of these 
programs is designed to protect water quality and, therefore, further 
the objective of the Clean Water Act. The agencies have also carefully 
considered the Act's policies regarding the responsibilities and rights 
of Tribes and States. See section IV.A.3.b of this preamble. The 
agencies have thus construed ``waters of the United States'' to include 
waters that meet the significant nexus standard based on the text of 
the Clean Water Act's interlocking provisions designed to restore and 
maintain the chemical, physical, and biological integrity of the 
nation's waters.
    A significant nexus analysis is also consistent with the framework 
scientists apply to assess a river system--examining how the components 
of the system (e.g., wetlands or tributaries), alone or in the 
aggregate (in combination), in a region, contribute and connect to a 
river (significantly affect the chemical, physical, or biological 
integrity of paragraph (a)(1) waters). Indeed, the significant nexus 
standard in this rule reflects the analysis in the Science Report by 
describing the components of a river system and watershed; the types of 
chemical, physical, and biological connections that link those 
components; the factors that influence connectivity and associated 
effects at various temporal and spatial scales; and methods for 
assessing downstream effects. The structure and function of rivers are 
highly dependent on the constituent materials stored in and transported 
through them. Most of these materials originate from either the 
upstream river network or other components of the river system, 
including wetlands, and then are transported to the river by water 
movement or other mechanisms. Further, the significant nexus standard 
is supported by the Science Report's discussion of connectivity, a 
foundational concept in hydrology and freshwater and marine ecology. 
See also Technical Support Document sections I.A.ii and III.E.
    Connectivity is the degree to which components of a system are 
joined or linked by various transport mechanisms and is determined by 
the characteristics of both the physical landscape and the biota of the 
specific system. Connectivity serves to demonstrate the ``nexus'' 
between upstream waterbodies and traditional navigable waters, the 
territorial seas, or interstate waters, and variations in the degree of 
connectivity influence the range of functions provided by streams, 
wetlands, and open waters and are critical to the integrity and 
sustainability of paragraph (a)(1) waters. For example, connections 
with low values of one descriptor can have important downstream effects 
when considered in context of other types of connections (e.g., a 
stream with low-duration flow during a flash flood can transfer large 
volumes of water and woody debris downstream, affecting the integrity 
of a paragraph (a)(1) water). Indeed, the seasonal or longer-term 
absence of surface connections can provide numerous functions that 
contribute to the chemical, physical, and biological integrity of 
paragraph (a)(1) waters: these wetlands can attenuate stormflow; 
increase baseflow; be a source of carbon and organic matter; and be a 
sink for sediment, nitrate, and other constituents that degrade water 
quality. While the scientific literature does not use the term 
``significant'' in the same manner used by the Supreme Court, the 
literature does provide information on the strength of upstream effects 
on the chemical, physical, and biological functioning of the downstream 
waterbodies. The analysis in the literature permits the agencies to 
judge when an effect is significant such that a water, either alone or 
in combination with similar waters, should be protected by the Clean 
Water Act in order to meet the objective of the Act. The Science Report 
presents evidence of connections for various categories of waters, 
evaluated singly or in combination, which affect downstream waters and 
the strength of those effects. The

[[Page 3036]]

connections and mechanisms discussed in the Science Report include 
transport of physical materials and chemicals such as water, wood, 
sediment, nutrients, pesticides, and metals (e.g., mercury); functions 
that streams, wetlands, and open waters perform, such as storing and 
cleansing water; and movement of organisms. Again, the significant 
nexus standard, under which waters are assessed alone or in combination 
for the functions they provide to paragraph (a)(1) waters, is 
consistent with the foundational scientific framework and concepts of 
hydrology.
    The agencies' use of scientific principles to determine the scope 
of ``waters of the United States'' is consistent with the Supreme 
Court's approach in Maui. The Court in that case also looked to 
scientific principles to inform its interpretation of the Clean Water 
Act's jurisdictional scope, noting: ``[m]uch water pollution does not 
come from a readily identifiable source. Rainwater, for example, can 
carry pollutants (say, as might otherwise collect on a roadway); it can 
pollute groundwater, and pollution collected by unchanneled rainwater 
runoff is not ordinarily considered point source pollution.'' Maui, 140 
S. Ct. at 1471 (citing the definition of ``water pollution'' from 3 Van 
Nostrand's Scientific Encyclopedia, at 5801). The Court then enumerated 
a series of factors, many of which are scientifically based, relevant 
to determining whether a discharge is jurisdictional under the Clean 
Water Act, including the nature of the material through which the 
pollutant travels and the extent to which the pollutant is diluted or 
chemically changed as it travels. Id. at 1476-77.
    In carefully considering the text and objective of the Clean Water 
Act and the best available science, this rule's incorporation of the 
significant nexus standard is also consistent with the legislative 
history of the Clean Water Act. The Supreme Court has noted that ``some 
Members of this Court have consulted legislative history when 
interpreting ambiguous statutory language.'' Bostock v. Clayton Cnty., 
Ga., 140 S. Ct. 1731, 1749 (2020) (emphasis in original). In Bostock, 
the Court stated further that ``while legislative history can never 
defeat unambiguous statutory text, historical sources can be useful for 
a different purpose: Because the law's ordinary meaning at the time of 
enactment usually governs, we must be sensitive to the possibility a 
statutory term that means one thing today or in one context might have 
meant something else at the time of its adoption or might mean 
something different in another context. And we must be attuned to the 
possibility that a statutory phrase ordinarily bears a different 
meaning than the terms do when viewed individually or literally. To 
ferret out such shifts in linguistic usage or subtle distinctions 
between literal and ordinary meaning, this Court has sometimes 
consulted the understandings of the law's drafters.'' Id. at 1750.
    Bills introduced in 1972 in both the House of Representatives and 
the Senate defined ``navigable waters'' as ``the navigable waters of 
the United States.'' See 2 Environmental Policy Div., Library of 
Congress, Legislative History of the Water Pollution Control Act 
Amendments of 1972 at 1069, 1698 (1973). The House and Senate 
Committees, however, expressed concern that the definition might be 
given an unduly narrow reading. Thus, the House Report observed: ``One 
term that the Committee was reluctant to define was the term `navigable 
waters.' The reluctance was based on the fear that any interpretation 
would be read narrowly. However, this is not the Committee's intent. 
The Committee fully intends that the term `navigable waters' be given 
the broadest possible constitutional interpretation unencumbered by 
agency determinations which have been made or may be made for 
administrative purposes.'' H.R. Rep. No. 92-911, at 131 (1972).
    The Senate Report stated that ``[t]hrough a narrow interpretation 
of the definition of interstate waters the implementation [of the] 1965 
Act was severely limited. Water moves in hydrologic cycles and it is 
essential that discharge of pollutants be controlled at the source.'' 
S. Rep. No. 92-414, at 77 (1971). The Conference Committee deleted the 
word ``navigable'' from the definition of ``navigable waters,'' broadly 
defining the term to include ``the waters of the United States.'' The 
Conference Report explained that the definition was intended to 
repudiate earlier limits on the reach of Federal water pollution 
efforts: ``The conferees fully intend that the term `navigable waters' 
be given the broadest possible constitutional interpretation 
unencumbered by agency determinations which have been made or may be 
made for administrative purposes.'' S. Conf. Rep. No. 92-1236, at 144 
(1972). The significant nexus standard thus fulfills Congress's intent 
that the scope of the term ``navigable waters'' be broader than the 
limitations of earlier water pollution control statutes and agency 
determinations under them (section 10 waters and their tributaries, for 
example, under the Rivers and Harbors Act of 1899). And, because the 
significant nexus standard is focused on protecting waters to meet the 
objective of the Act, it also comports with congressional intent.
    The significant nexus standard is also consistent with prior 
Supreme Court decisions and with every circuit decision that has 
gleaned a rule of law from that precedent. For example, in Riverside 
Bayview, the Court deferred to the agencies' interpretation: ``In view 
of the breadth of Federal regulatory authority contemplated by the Act 
itself and the inherent difficulties of defining precise bounds to 
regulable waters, the Corps' ecological judgment about the relationship 
between waters and their adjacent wetlands provides an adequate basis 
for a legal judgment that adjacent wetlands may be defined as waters 
under the Act.'' 474 U.S. at 134. Indeed, the Court in Riverside 
Bayview concluded that ``significant effects'' is the relevant basis 
for asserting jurisdiction over adjacent wetlands: ``If it is 
reasonable for the Corps to conclude that in the majority of cases, 
adjacent wetlands have significant effects on water quality and the 
aquatic ecosystem, its definition can stand.'' Id. at 135 n.9. In 
Rapanos, Justice Kennedy--referencing the Court in Riverside Bayview--
stated that ``the Court indicated that `the term ``navigable'' as used 
in the Act is of limited import,' [and] it relied, in upholding 
jurisdiction, on the Corps' judgment that `wetlands adjacent to lakes, 
rivers, streams, and other bodies of water may function as integral 
parts of the aquatic environment even when the moisture creating the 
wetlands does not find its source in the adjacent bodies of water.' '' 
547 U.S. at 779 (Kennedy, J., concurring in the judgment) (citing 
Riverside Bayview, 474 U.S. at 133, 135). ``The implication,'' Justice 
Kennedy observed, ``was that wetlands' status as `integral parts of the 
aquatic environment'--that is, their significant nexus with navigable 
waters--was what established the Corps' jurisdiction over them as 
waters of the United States.'' Rapanos, 547 U.S. at 779 (emphasis 
added); see also id. at 780 (``[W]etlands' ecological functions vis-
[aacute]-vis other covered waters are the basis for the Corps' 
regulation of them.''). The Court in SWANCC also characterized its 
decision in Riverside Bayview as informed by the ``significant nexus 
between the wetlands and `navigable waters.' '' 531 U.S. at 167.
    In Rapanos, Justice Kennedy reasoned that Riverside Bayview and 
SWANCC

[[Page 3037]]

``establish the framework for'' determining whether an assertion of 
regulatory jurisdiction constitutes a reasonable interpretation of 
``navigable waters,'' finding that ``the connection between a 
nonnavigable water or wetland and a navigable water may be so close, or 
potentially so close, that the Corps may deem the water or wetland a 
`navigable water' under the Act,'' and ``[a]bsent a significant nexus, 
jurisdiction under the Act is lacking.'' 547 U.S. at 767. Justice 
Kennedy also identified many of the same valuable wetland functions as 
the Science Report: ``Important public interests are served by the 
Clean Water Act in general and by the protection of wetlands in 
particular. To give just one example, amici here have noted that 
nutrient-rich runoff from the Mississippi River has created a hypoxic, 
or oxygen-depleted, `dead zone' in the Gulf of Mexico that at times 
approaches the size of Massachusetts and New Jersey. Scientific 
evidence indicates that wetlands play a critical role in controlling 
and filtering runoff'' Id. at 777 (citing Brief for Association of 
State Wetland Managers et al. 21-23; Brief for Environmental Law 
Institute 23; OTA 43, 48-52; R. Tiner, In Search of Swampland: A 
Wetland Sourcebook and Field Guide 93-95 (2d ed. 2005); Whitmire & 
Hamilton, Rapid Removal of Nitrate and Sulfate in Freshwater Wetland 
Sediments, 34 J. Env. Quality 2062 (2005)).
    The agencies are mindful of the Supreme Court's decision in SWANCC 
regarding the specific Commerce Clause authority Congress was 
exercising in enacting the Clean Water Act--``its traditional 
jurisdiction over waters that were or had been navigable in fact or 
which could reasonably be so made''--and the Court's guidance on 
avoiding an administrative interpretation of a statute that invokes the 
outer limits of Congress's power. 531 U.S. at 172; see also id. (``[W]e 
expect a clear indication that Congress intended that result.''). With 
respect to section 404 authority over an abandoned sand and gravel pit 
based simply on whether it was used by migratory birds (the ``Migratory 
Bird Rule''), the SWANCC Court concluded that there was not a clear 
statement from Congress. Id. at 174. By placing traditional navigable 
waters, the territorial seas, and interstate waters at the center of 
the agencies' jurisdiction and covering additional waters only where 
those waters significantly affect (a)(1) waters, this rule reflects the 
Court's guidance. Further, in construing the statute in this rule, the 
agencies have not only eschewed the ``Migratory Bird Rule,'' they have 
deleted the provisions in the 1986 regulations that authorized 
assertions of jurisdiction under broader Commerce Clause authority and 
replaced them with the relatively permanent and significant nexus 
standards.
    Indeed, the provisions in the 1986 regulations authorized 
assertions of jurisdiction far more broadly than under the relatively 
permanent standard and significant nexus standard in this rule. First, 
the regulatory text authorized the assertion of jurisdiction over 
``[a]ll other waters such as intrastate 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 could affect interstate or 
foreign commerce including any such waters: Which are or could be used 
by interstate or foreign travelers for recreational or other purposes; 
or From which fish or shellfish are or could be taken and sold in 
interstate or foreign commerce; or Which are used or could be used for 
industrial purposes by industries in interstate commerce.'' 33 CFR 
328.3(a)(3) (2014). This regulatory text was based on all three 
categories of activity that Congress may regulate using its Commerce 
Clause authority: (1) the channels of interstate commerce; (2) persons 
or things in interstate commerce; and (3) activities that substantially 
affect interstate commerce. See United States v. Lopez, 514 U.S. 549, 
558-59 (1995). This approach thus overall was a far broader definition 
of ``waters of the United States'' than this rule, which recognizes 
that the Supreme Court in SWANCC held that Congress was not using all 
aspects of its Commerce Clause authority. Moreover, as discussed by the 
Court in SWANCC, the agencies stated in the preamble to the 1986 
regulations that ``waters of the United States'' at 33 CFR 328.3(a)(3) 
also included waters that ``are or would be used as habitat by birds 
protected by Migratory Bird Treaties; . . . [that] are or would be used 
as habitat by other migratory birds which cross state lines; . . . 
[that] are or would be used as habitat for endangered species; or . . . 
[waters] [u]sed to irrigate crops sold in interstate commerce.'' 51 FR 
41206, 41217 (November 13, 1986). This is the 1986 preamble language 
that became known as the ``Migratory Bird Rule'' and clearly 
established a far greater scope of ``waters of the United States'' than 
this rule, as migratory birds use waters large and small all over the 
United States with no connection to a traditional navigable water, the 
territorial seas, or an interstate water.
    The agencies also have carefully amended other provisions of the 
1986 regulations not only to add the relatively permanent standard and 
the significant nexus standard as limitations on the scope of ``waters 
of the United States'' but to add additional limitations where the 
agencies were concerned assertions of jurisdiction could push the 
limits of the congressional authority granted to the agencies or 
constitutional limits. For example, in a change from the 1986 
regulations, tributaries to intrastate lakes and ponds, streams, and 
wetlands that do not fall within other categories of the rule 
(paragraph (a)(5) waters in this rule, which are analogous to the 
``other waters'' provision of the 1986 regulations) do not qualify as 
tributaries under this rule, nor do wetlands adjacent to such waters. 
As set forth in this rule, the relatively permanent standard and the 
significant nexus standard allow the agencies to fulfill the statute 
and Congress's clearly stated objective, while being carefully crafted 
to fall well within the authority granted to the agencies by Congress 
and to Congress by the Constitution. As noted above, the SWANCC Court 
itself viewed ``significant nexus'' as the touchstone for determining 
the scope of ``waters of the United States'' in its decision in 
Riverside Bayview, concluding the decision was informed by the 
``significant nexus between the wetlands and `navigable waters.' '' 531 
U.S. at 167. The agencies agree with the analysis of Justice Kennedy, 
who explicitly addressed these constitutional concerns in Rapanos, 
stating: ``In SWANCC, by interpreting the Act to require a significant 
nexus with navigable waters, the Court avoided applications--those 
involving waters without a significant nexus--that appeared likely, as 
a category, to raise constitutional difficulties and federalism 
concerns.'' 547 U.S. at 776. Moreover, the rule is consistent with 
decades of interpretation and implementation undisturbed by Congress.
    Moreover, the SWANCC Court noted that the statement in the 
Conference Report for the Clean Water Act that the conferees ``intend 
that the term `navigable waters' be given the broadest possible 
constitutional interpretation,'' S. Conf. Rep. No. 92-1236, at 144 
(1972), signifies Congress's intent with respect to its exertion of its 
commerce power over navigation. As the numerous Supreme Court decisions 
discussed above have found, Congress enacted the Clean Water Act to 
establish a comprehensive Federal law protecting

[[Page 3038]]

water quality. The agencies' construction of the statute must also give 
effect to the clearly stated objective of the Act and all the 
provisions of the Act designed to achieve that objective. See section 
IV.A.2 of this preamble. Thus, while the agencies must be mindful that 
Congress was utilizing an aspect of its commerce power, they must be 
similarly mindful that Congress intended to fully exercise that 
authority in order to comprehensively address water pollution. The 
agencies have concluded that the legislative history concerning the 
intent of Congress regarding the scope of the Clean Water Act's 
protections under its power over navigation confirms the 
appropriateness of the agencies' construction of the Clean Water Act in 
this rule. This rule ensures that waters, which either alone or in 
combination significantly affect the integrity of traditional navigable 
waters, the territorial seas, or interstate waters, are protected by 
the Clean Water Act, and thus this rule carefully balances the limits 
on Congress's authority and on the agencies' authority under the Act, 
with congressional intent to comprehensively protect water quality and 
to delegate the authority to do so to the agencies.
    Finally, the Supreme Court has long held that authority over 
traditional navigable waters is not limited to either protection of 
navigation or authority over only the traditional navigable water. 
Rather, ``the authority of the United States is the regulation of 
commerce on its waters . . . [f]lood protection, watershed development, 
[and] recovery of the cost of improvements through utilization of power 
are likewise parts of commerce control.'' United States v. Appalachian 
Electric Power Co., 311 U.S. 377, 426 (1940); see also Oklahoma ex rel. 
Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 525-526 (1941) (``[J]ust 
as control over the non-navigable parts of a river may be essential or 
desirable in the interests of the navigable portions, so may the key to 
flood control on a navigable stream be found in whole or in part in 
flood control on its tributaries. . . . [T]he exercise of the granted 
power of Congress to regulate interstate commerce may be aided by 
appropriate and needful control of activities and agencies which, 
though intrastate, affect that commerce.''). As the United States Court 
of Appeals for the Sixth Circuit observed after the 1972 enactment of 
the Clean Water Act: ``It would, of course, make a mockery of 
[Congress's] powers if its authority to control pollution was limited 
to the bed of the navigable stream itself. The tributaries which join 
to form the river could then be used as open sewers as far as federal 
regulation was concerned. The navigable part of the river could become 
a mere conduit for upstream waste.'' United States v. Ashland Oil & 
Transp. Co., 504 F.2d 1317, 1326 (6th Cir. 1974). The significant nexus 
standard included in this rule ensures that the definition of ``waters 
of the United States'' remains within the bounds of the Clean Water Act 
and addresses the concerns raised by the Court in SWANCC while also 
fulfilling the directive of Congress in enacting the Clean Water Act.
ii. The Relatively Permanent Standard Is Administratively Useful, But 
Exclusive Reliance on the Standard for All Determinations Is 
Inconsistent With the Objective of the Act
    The agencies conclude that Federal protection is appropriate where 
a water meets the relatively permanent standard: waters that are 
relatively permanent, standing or continuously flowing waters connected 
to paragraph (a)(1) waters, and waters with a continuous surface 
connection to such relatively permanent waters or to paragraph (a)(1) 
waters. Waters that meet this standard are a subset of the ``waters of 
the United States'' because they will virtually always significantly 
affect traditional navigable waters, the territorial seas, or 
interstate waters and therefore properly fall within the Clean Water 
Act's scope. However, limiting the definition of ``waters of the United 
States'' to the relatively permanent standard on its own would be 
inconsistent with the Act's text and objective and runs counter to 
scientific principles. As discussed further below, the agencies have 
included the relatively permanent standard in this rule because it 
provides efficiencies and additional clarity for regulators and the 
public.
    Waters that meet the relatively permanent standard are within the 
scope of the Clean Water Act because scientific evidence supports the 
conclusion that tributaries of paragraph (a)(1) waters with relatively 
permanent, standing or continuously flowing water perform important 
functions that either individually, or cumulatively with similarly 
situated waters in the region, have significant effects on the 
chemical, physical, or biological integrity of paragraph (a)(1) waters. 
The same is true of adjacent wetlands and relatively permanent open 
waters with continuous surface connections to tributaries that meet the 
relatively permanent standard. See Technical Support Document sections 
III.A, III.B, and III.D. Tributaries that meet the relatively permanent 
standard contribute consistent flow to paragraph (a)(1) waters and, 
with that flow, export nutrients, sediment, food resources, 
contaminants, and other materials that can both positively (e.g., by 
contributing to downstream baseflow, providing food for aquatic 
species, and contributing to downstream aquatic habitat) and negatively 
(e.g., by exporting too much sediment, runoff, or nutrients or 
exporting pollutants) affect the integrity of those paragraph (a)(1) 
waters. In addition, wetlands with a continuous surface connection to 
tributaries that meet the relatively permanent standard can and do 
attenuate floodwaters, trap sediment, and process and transform 
nutrients that might otherwise reach traditional navigable waters, the 
territorial seas, or interstate waters. If the agencies assessed waters 
that meet the relatively permanent standard (e.g., tributaries that 
meet the relatively permanent standard or adjacent wetlands with a 
continuous surface connection to such tributaries) they would virtually 
always find evidence of strong factors, particularly hydrologic factors 
like flow frequency and duration, that lead to strong connections and 
associated effects on paragraph (a)(1) waters. Therefore, waters that 
meet the relatively permanent standard will virtually always meet the 
significant nexus standard.
    The relatively permanent standard is useful for the agencies and 
the public because it generally requires less information gathering and 
assessment than the significant nexus standard. The significant nexus 
standard requires evaluating whether waters, alone or in combination, 
significantly affect the chemical, physical, or biological integrity of 
paragraph (a)(1) waters, i.e., traditional navigable waters, the 
territorial seas, and interstate waters. Such an assessment requires 
considering the presence of functions for one or more subject waters 
and evaluating the strength of their effects on paragraph (a)(1) 
waters. In contrast, the relatively permanent standard has a more 
limited focus that requires considering the flow of a tributary or 
considering the surface connection between an adjacent wetland or open 
water and a relatively permanent covered water. As such, while both the 
significant nexus and relatively permanent standards require case-
specific, fact-based inquiries before determining whether a water meets 
the definition of ``waters of the United States,'' the relatively 
permanent standard will generally require less

[[Page 3039]]

assessment and thus can result in administrative efficiencies.
    Standing alone as the sole test for Clean Water Act jurisdiction, 
however, the relatively permanent standard has no basis in the text of 
the statute and is contrary to the statute. Rather than a careful 
consideration of the Clean Water Act's specialized definitions in light 
of the objective of the Act, the standard's apparent exclusion of major 
categories of waters from the protections of the Clean Water Act, 
specifically with respect to tributaries that are not relatively 
permanent and adjacent wetlands that do not have a continuous surface 
connection to such relatively permanent waters or to paragraph (a)(1) 
waters, is inconsistent with the Act's text and objective. In addition, 
the relatively permanent standard used alone runs counter to the 
science demonstrating how other categories of waters can affect the 
integrity of downstream waters, including traditional navigable waters, 
the territorial seas, and interstate waters. For example, many 
tributaries that flow for only a short duration in direct response to 
precipitation, and thus do not meet the relatively permanent standard, 
are regular and direct sources of freshwater for the sparse traditional 
navigable waters in the arid Southwest, such as portions of the Gila 
River. In addition, many adjacent wetlands do not have a continuous 
surface connection to jurisdictional waters but provide numerous flood 
protection and water quality benefits to traditional navigable waters, 
such as wetlands behind the extensive levee systems along the 
Mississippi River.
    As discussed in section IV.A.2.c of this preamble and sections 
III.A.v and III.B of the Technical Support Document, there is 
overwhelming scientific information demonstrating the effects ephemeral 
streams can have on downstream waters and the effects wetlands can have 
on downstream waters when they do not have a continuous surface 
connection. The science is clear that aggregate effects of ephemeral 
streams ``can have substantial consequences on the integrity of the 
downstream waters'' and that the evidence of such downstream effects is 
``strong and compelling.'' Science Report at 6-10, 6-13. The SAB review 
of the draft Science Report explained that ephemeral streams ``are no 
less important to the integrity of the downgradient waters'' than 
perennial or intermittent streams.\60\ There is thus no scientific 
basis for excluding waters simply because they are not relatively 
permanent.
---------------------------------------------------------------------------

    \60\ Letter from SAB to Gina McCarthy, Administrator, EPA 
(October 17, 2014) (``2014 SAB Review'') at 22-23, 54 fig. 3.
---------------------------------------------------------------------------

    The science is also clear that wetlands may significantly affect 
paragraph (a)(1) waters when they have other types of surface or 
hydrologic connections, such as wetlands that overflow across uplands 
via sheetflow and flood jurisdictional waters or wetlands with less 
frequent surface water connections; wetlands with shallow subsurface 
connections to other protected waters; wetlands behind a natural berm, 
a beach dune, a manmade levee, or the like; or other wetlands proximate 
to jurisdictional waters. Such wetlands provide a number of functions, 
including water storage that can help reduce downstream flooding; 
recharging groundwater that contributes to baseflow of paragraph (a)(1) 
waters; improving water quality in paragraph (a)(1) waters through 
processes that remove, store, or transform pollutants such as nitrogen, 
phosphorus, and metals; and serving as unique and important habitats 
including for aquatic species that also utilize paragraph (a)(1) 
waters. See, e.g., Science Report at 4-20 to 4-38.
    The agencies have also concluded that there is no basis in the text 
of the statute to exclude waters from Clean Water Act jurisdiction 
solely because they do not meet the relatively permanent standard. As 
discussed in section IV.A.2.a of this preamble, the objective of the 
Clean Water Act is to restore and maintain the water quality of the 
nation's waters. The phrase ``waters of the United States'' is by its 
terms expansive and not expressly limited to relatively permanent, 
standing or continuously flowing bodies of water, or to wetlands with a 
continuous surface connection. The imposition of such limitations would 
disregard the science demonstrating the effects of upstream waters and 
wetlands on downstream paragraph (a)(1) waters. Taking science into 
account, the agencies agree with Justice Kennedy that the Clean Water 
Act intends to protect waters that do not meet the relatively permanent 
standard, where such waters have a significant nexus to a paragraph 
(a)(1) water. Rapanos, 547 U.S. at 773-74 (Kennedy, J., concurring in 
the judgment) (``Needless to say, a continuous connection is not 
necessary for moisture in wetlands to result from flooding--the 
connection might well exist only during floods.''); see also id. at 775 
(``In many cases, moreover, filling in wetlands separated from another 
water by a berm can mean that floodwater, impurities, or runoff that 
would have been stored or contained in the wetlands will instead flow 
out to major waterways. With these concerns in mind, the Corps' 
definition of adjacency is a reasonable one, for it may be the absence 
of an interchange of waters prior to the dredge and fill activity that 
makes protection of the wetlands critical to the statutory scheme.'').
    The agencies have concluded that there is no sound basis in the 
text of the statute to exclude tributaries solely on the basis that 
they are not relatively permanent, standing or continuously flowing 
bodies of water from the Clean Water Act. In interpreting the Clean 
Water Act to be limited in such a manner, the Rapanos plurality relied 
on a strained reading of the Act that is inconsistent with the text of 
the statute--including the statute's stated objective--the structure of 
the statute, the statutory history, and Supreme Court precedent 
interpreting the Clean Water Act.
    First, the plurality stated that because one entry in a dictionary 
defines ``waters'' to mean ``water `[a]s found in streams and bodies 
forming geographical features such as oceans, rivers, [and] lakes,' or 
`the flowing or moving masses, as of waves or floods, making up such 
streams or bodies,' '' Rapanos, 547 U.S. at 732 (quoting Webster's New 
International Dictionary 2882 (2d ed. 1954) (hereinafter, ``Webster's 
Second'')), the phrase ``navigable waters'' permits Corps and EPA to 
assert jurisdiction only over ``relatively permanent, standing or 
flowing bodies of water.'' Rapanos, 547 U.S. at 732. The plurality 
leans heavily on the fact that Congress defined ``navigable waters'' as 
``the waters of the United States.'' 33 U.S.C. 1362(7) (emphasis 
added). But the article ``the'' and plural ``waters'' cannot bear this 
weight. Congress used the term ``the waters'' throughout the Clean 
Water Act and in usages where it would be illogical to swap in the 
plurality's preferred definition. For example, throughout the Act, 
Congress frequently refers to ``the waters of the contiguous zone'' and 
even ``the waters of the territorial seas, the contiguous zone, and the 
oceans.'' 33 U.S.C. 1343(a), (c) (emphasis added). Congress is not 
making a careful distinction between some of ``the waters'' of the 
contiguous zone and other waters of the contiguous zone based on a 
dictionary definition. Nor did Congress intend to single out some 
waters of the Great Lakes when it instructed the Administrator to 
``conduct research and technical development work, and make studies, 
with respect to the quality of the waters of the Great Lakes.'' 33 
U.S.C. 1254(f) (emphasis added).

[[Page 3040]]

    The plurality relied on one particular dictionary definition to 
limit the scope of the ``waters of the United States'' in a way that is 
neither compelled by, nor consistent with, the text of the statute. The 
plurality selected a dictionary, Webster's Second that was not even the 
most recent edition as of passage of the Clean Water Act, and thus not 
as reflective of common usage, and then selected a preferred definition 
within that dictionary. See Rapanos, 547 U.S. at 732. Webster's Second 
does not have a separate entry for ``waters'' (plural), so the 
plurality relied on its entry for ``water'' (singular) and within that 
skipped over several more apt definitions to reach its preferred one. 
The first definition of ``water'' within Webster's Second (1.a. of the 
definition) is ``[t]he liquid which descends from the clouds in rain 
and which forms rivers, lakes, seas, etc.,'' a definition that is 
substantially broader than the one chosen by the plurality. The 
plurality's preferred definition, ``water as found in streams and 
bodies forming geographical features such as oceans, rivers, and 
lakes,'' is halfway down the column, definition 2.c. Moreover, the 
definition of ``waters,'' plural, in the most contemporaneous 
Webster's, was also substantially broader, providing the following 
definition: ``the water occupying or flowing in a particular bed.'' 
Webster's Third New Intl. (1966). Even taking the plurality's preferred 
definition at face value, it does not support the relatively permanent 
standard. That definition includes ``water as found in streams.'' The 
plurality concluded that the streams referred to in the definition must 
be relatively permanent and thereby concluded that the ``waters of the 
United States'' do not include intermittent and ephemeral streams 
(although the plurality did not use those terms in the scientific sense 
and added caveats to its stated textual reading of the statute--stating 
that ``relatively permanent'' does not necessarily exclude waters 
``that might dry up in extraordinary circumstances, such as drought'' 
or ``seasonal rivers, which contain continuous flow during some months 
of the year but no flow during dry months''). Rapanos, 547 U.S. at 732 
n.5 (emphasis in original). Intermittent and ephemeral streams are, of 
course, ``streams''--as they are defined in the dictionary, understood 
in common parlance, and defined by scientists.
    The agencies thus agree with Justice Kennedy that the limitations 
the plurality imposes on the Clean Water Act ``are without support in 
the language and purposes of the Act or in our cases interpreting it.'' 
Rapanos, 547 U.S. at 768. The agencies also agree that a permanent 
standing water or continuous flow requirement ``makes little practical 
sense in a statute concerned with downstream water quality.'' Id. at 
769. And, as discussed above, ``a full reading of the dictionary 
definition precludes the plurality's emphasis on permanence: The term 
`waters' may mean `flood or inundation,' events that are impermanent by 
definition;'' it follows that ``the Corps can reasonably interpret the 
Act to cover the paths of such impermanent streams.'' Id. at 770 
(quoting Webster's Second 2882).
    The agencies also have concluded that Riverside Bayview does not 
support the plurality's standard for tributaries. As Justice Kennedy 
stated: ``To be sure, the Court there compared wetlands to `rivers, 
streams, and other hydrographic features more conventionally 
identifiable as ` ``waters.'' ' Rapanos, 547 U.S. at 771 (citing 
Riverside Bayview, 474 U.S. at 131). ``It is quite a stretch to claim, 
however, that this mention of hydrographic features `echoe[s]' the 
dictionary's reference to ` ``geographical features such as oceans, 
rivers, [and] lakes.'' ' Rapanos, 547 U.S. at 771 (citation omitted). 
``In fact, the Riverside Bayview opinion does not cite the dictionary 
definition on which the plurality relies, and the phrase `hydrographic 
features' could just as well refer to intermittent streams carrying 
substantial flow to navigable waters.'' Id. at 771 (citing Webster's 
Second 1221 (defining ``hydrography'' as ``[t]he description and study 
of seas, lakes, rivers, and other waters; specif[ically] . . . [t]he 
measurement of flow and investigation of the behavior of streams, 
esp[ecially] with reference to the control or utilization of their 
waters'')).
    With respect to wetlands, the agencies have also concluded there is 
no sound basis in the text of the Clean Water Act or in other Supreme 
Court precedent for requiring that wetlands can be jurisdictional only 
if they satisfy the continuous surface connection requirement of the 
relatively permanent standard. The Rapanos plurality's rationale for 
adopting such a test rested largely on a misreading of Riverside 
Bayview. The plurality's brief discussion did not otherwise attempt to 
ground its relatively permanent standard in the text, history, or 
purpose of the Clean Water Act. In concluding that only wetlands with a 
continuous surface connection to other covered waters are protected by 
the Clean Water Act, the Rapanos plurality relied primarily on two 
related propositions that it viewed as implicit in Riverside Bayview. 
First, the plurality suggested that in Riverside Bayview the Clean 
Water Act term ``waters'' cannot easily be construed to cover wetlands, 
and that discharges into wetlands therefore can be regulated only when 
particular wetlands ``adjoined'' waters of the United States and were 
thus deemed ``part of'' the waters to which they are adjacent. See 547 
U.S. at 740. Second, the plurality concluded that this requirement will 
be satisfied only when ``the wetland has a continuous surface 
connection with [the adjacent] water.'' Id. at 742. Those propositions 
are unsound and rest on a misreading of Riverside Bayview.
    The Rapanos plurality quoted the Riverside Bayview Court's 
statement that, ``[o]n a purely linguistic level, it may appear 
unreasonable to classify `lands,' wet or otherwise, as `waters.' '' 547 
U.S. at 740 (quoting Riverside Bayview, 474 U.S. at 132). In the next 
sentence of its opinion, however, the Riverside Bayview Court 
continues, and the Rapanos plurality omits, that ``[s]uch a simplistic 
response . . . does justice neither to the problem faced by the Corps 
in defining the scope of its authority under Sec.  404(a) nor to the 
realities of the problem of water pollution that the Clean Water Act 
was intended to combat.'' 474 U.S. at 132. The Riverside Bayview Court 
concluded that ``adjacent wetlands may be defined as waters under the 
Act.'' Id. at 134. And, as explained above, the Clean Water Act's text, 
history, and purpose likewise confirm that adjacent wetlands are 
themselves ``waters'' covered by the Act.
    The Rapanos plurality read Riverside Bayview as resting on the 
``inherent ambiguity in drawing the boundaries of any `waters.''' 547 
U.S. at 740. The plurality also described SWANCC as having read 
Riverside Bayview to be ``refer[ring] to the close connection between 
waters and the wetlands that they gradually blend into.'' Rapanos, 547 
U.S. at 741. The plurality concluded that ``only those wetlands with a 
continuous surface connection to bodies that are `waters of the United 
States' in their own right'' can be protected by the Clean Water Act, 
because only in that circumstance is it ``difficult to determine where 
the `water' ends and the `wetland' begins.'' Id. at 742. However, the 
Rapanos plurality misconceived the nature of the line-drawing problem 
in Riverside Bayview. The Riverside Bayview Court identified 
``shallows, marshes, mudflats, swamps, [and] bogs'' as examples of 
``areas that are not wholly aquatic but nevertheless fall far short of 
being dry land,'' and it

[[Page 3041]]

observed that ``[w]here on this continuum to find the limit of `waters' 
is far from obvious.'' 474 U.S. at 132. The line-drawing problem in 
Riverside Bayview did not involve identifying the boundary between a 
jurisdictional stream and an adjacent wetland. Rather, the line-drawing 
problem involved the criteria that should be used to determine whether 
particular types of hydrogeographic features should be regarded as 
``waters'' under the Clean Water Act. That line-drawing problem--in 
essence, determining how wet is wet enough--can arise even when a 
particular swamp or marsh is separated by a barrier from a nearby lake 
or stream. After discussing at some length the regulatory definition of 
``wetlands'' and its application to the property at issue in that case, 
see id. at 129-131, the Riverside Bayview Court upheld as reasonable 
``the Corps' approach of defining adjacent wetlands as `waters' within 
the meaning of'' the Clean Water Act. Id. at 132.
    As further support for its relatively permanent standard, the 
Rapanos plurality invoked SWANCC's holding that certain isolated ponds 
were not covered by the Clean Water Act. The SWANCC Court had described 
Riverside Bayview as resting on ``the significant nexus between the 
wetlands and'' the waters to which they are adjacent. 531 U.S. at 167. 
The Rapanos plurality in turn described SWANCC as ``reject[ing] the 
notion that the ecological considerations upon which the Corps relied 
in Riverside Bayview . . . provided an independent basis for including 
entities like `wetlands' . . . within the phrase `the waters of the 
United States.' '' 547 U.S. at 741 (citation omitted). In the 
plurality's view, ``SWANCC found such ecological considerations 
irrelevant to the question whether physically isolated waters come 
within the Corps' jurisdiction,'' because the coverage inquiry for the 
``[i]solated ponds'' at issue in that case ``presented no boundary-
drawing problem that would have justified the invocation of ecological 
factors.'' Id. at 741-742. Contrary to the Rapanos plurality's 
suggestion, the Court in SWANCC did not hold that the particular 
``ecological considerations upon which the Corps relied in Riverside 
Bayview,'' 547 U.S. at 741--i.e., the potential importance of wetlands 
to the quality of adjacent waters--were irrelevant to Clean Water Act 
jurisdiction. Rather, the Court held that a different ecological 
concern, namely the potential use of the isolated ponds as habitat for 
migratory birds, could not justify treating those ponds as ``waters of 
the United States.'' See 531 U.S. at 164-165, 171-172. That ecological 
concern was not cognizable because it was unrelated to ``what Congress 
had in mind as its authority for enacting the CWA: its traditional 
jurisdiction over waters that were or had been navigable in fact or 
which could reasonably be so made.'' Id. at 172 (citation omitted).
    Aside from its mistaken reliance on Riverside Bayview and SWANCC, 
the Rapanos plurality did not attempt to ground the relatively 
permanent standard in the Clean Water Act's text or history. See 547 
U.S. at 739-742. And limiting Clean Water Act coverage to wetlands with 
a continuous surface connection would affirmatively undermine the Act's 
purpose by creating an illogical jurisdictional gap. It would 
categorically exclude wetlands separated from covered waters by a dike 
or similar barrier, even if they are closely connected by subsurface 
flow or periodic floods, regardless of such wetlands' ecological 
importance to covered waters nearby and downstream. The agencies have 
concluded that overwhelming scientific evidence shows that such 
wetlands may significantly affect paragraph (a)(1) waters. See Science 
Report 4-20 to 4-38; Technical Support Document section III.B.
    Additionally, the relatively permanent standard was not briefed in 
Rapanos. See 547 U.S. at 800 (Stevens, J., dissenting). And the 
plurality's terse discussion of the issue did not elaborate on either 
aspect of that standard in any detail. The plurality stated that 
``relatively permanent'' does not necessarily exclude waters ``that 
might dry up in extraordinary circumstances, such as drought'' or 
``seasonal rivers, which contain continuous flow during some months of 
the year but no flow during dry months.'' 547 U.S. at 732 n.5 (emphasis 
in original). The Rapanos plurality distinguished a ``continuous 
surface connection'' from ``an intermittent, physically remote 
hydrologic connection,'' but gave little further guidance on the 
application of its test. Id. at 742 (plurality opinion). As long as the 
relatively permanent standard is understood as a useful but not 
exclusive standard for Clean Water Act coverage, it has not created 
arbitrary and harmful results.
    If the relatively permanent standard were the sole standard, a 
small surface connection would suffice, but the presence of a levee to 
protect a river and its adjacent wetlands could strip the wetlands of 
Clean Water Act coverage since, under the relatively permanent 
standard, a human-made barrier such as a levee means that there is not 
a continuous surface connection between the river and the wetlands. 
This result would be irrational and contrary to the objectives of the 
statute. The Mississippi River, for example, features an extensive 
levee system built to prevent flooding. The Upper Mississippi Valley 
alone includes approximately 17,000 kilometers (more than 10,000 miles) 
of levees. Technical Support Document section III.B.ii.2. Those levees 
would preclude Clean Water Act coverage under the relatively permanent 
standard even though adjacent wetlands are often a necessary part of 
the flood-control project--detaining floodwaters to protect surrounding 
and downstream communities--and even though the wetlands maintain a 
hydrologic connection to the river system. Cf. R. Daniel Smith & 
Charles V. Klimas, Eng'r Rsch. & Dev. Ctr., A Regional Guidebook for 
Applying the Hydrogeomorphic Approach to Assessing Wetland Functions of 
Selected Regional Wetland Subclasses, Yazoo Basin, Lower Mississippi 
River Alluvial Valley 47, 48-49 (April 2002).
    More broadly, the relatively permanent standard's continuous 
surface connection requirement could make loss of Clean Water Act 
jurisdiction a consequence of building a road, levee, or other 
barrier--even if the construction had little or no effect on the 
interdependent relationship between a wetland and a neighboring water. 
That could create perverse incentives to build or modify such barriers 
in a manner aimed either at destroying or preserving Federal 
jurisdiction.
    Further, as discussed above, Congress declined to narrow the scope 
of ``waters of the United States'' when it amended the Clean Water Act 
in 1977. The relatively permanent standard amends the Clean Water Act 
to limit its scope in ways that Congress has considered doing but has 
repeatedly declined to do, including through legislation introduced 
after the Rapanos decision and after promulgation of the 2020 NWPR.\61\ 
As Justice Kennedy stated:

[[Page 3042]]

``To be sure, Congress could draw a line to exclude irregular 
waterways, but nothing in the statute suggests it has done so. Quite 
the opposite.'' 547 U.S. at 770.
---------------------------------------------------------------------------

    \61\ See, e.g., Navigable Waters Protection Act, S. 2567, 117th 
Cong. (2021) (proposing to codify the 2020 NWPR as Federal 
legislation); Define WOTUS Act, S. 2356, 116th Cong. (2019) 
(proposing to revise the Clean Water Act to define ``navigable 
waters'' to include the territorial seas, interstate waters used in 
the transport of interstate or foreign commerce, and waters meeting 
the Rapanos plurality's standard); S.J. Res. 22, 114th Cong. (2015) 
(proposing to nullify the 2015 Clean Water Rule); Defense of 
Environment and Property Act, H.R. 3377, 113th Cong. (2013) 
(proposing to revise the Clean Water Act to limit ``waters of the 
United States'' to navigable-in-fact waters and ``permanent or 
continuously flowing bodies of water that form geographical features 
commonly known as streams, oceans, rivers, and lakes that are 
connected to waters that are navigable-in-fact''); Amendment 2177, 
S. 3240, 112th Cong. (2012) (proposing to amend an appropriations 
bill to limit the Clean Water Act's definition of ``waters of the 
United States'' to navigable-in-fact waters and ``permanent, 
standing or continuously flowing bodies of water that form 
geographical features commonly known as streams, oceans, rivers, and 
lakes that are connected to waters that are navigable-in-fact'').
---------------------------------------------------------------------------

    Finally, the agencies have consistently construed Rapanos to mean 
that a water is jurisdictional under the Clean Water Act if it meets 
either the relatively permanent standard or the significant nexus 
standard. The 2020 NWPR, however, interpreted the statute to primarily 
find waters jurisdictional only if they met the relatively permanent 
standard, as that standard was specifically interpreted in the 2020 
NWPR. The 2020 NWPR argued that it reflected both the plurality and 
Kennedy opinions, which it characterized as having ``sufficient 
commonalities . . . to help instruct the agencies on where to draw the 
line between Federal and State waters.'' 85 FR 22250, 22268 (April 21, 
2020). The opinions have important differences, however. Justice 
Kennedy looked to the existence of a significant nexus between waters 
at issue and traditional navigable waters, whereas the plurality held 
that ``waters of the United States'' is limited to ``relatively 
permanent'' waters connected to traditional navigable waters, and 
wetlands with a ``continuous surface connection'' with those waters. 
Rapanos, 547 U.S. at 742. Justice Kennedy rejected these two 
limitations in the plurality as ``without support in the language and 
purposes of the Act or in our cases interpreting it.'' Id. at 768; see 
also id. at 776 (``In sum the plurality's opinion is inconsistent with 
the Act's text, structure, and purpose.''). Yet the plurality's 
limitation of jurisdiction to ``relatively permanent'' waters and those 
with a ``continuous surface connection'' to those waters pervades the 
2020 NWPR. See 85 FR 22338-39; see also 2020 NWPR regulatory text at 33 
CFR 328.3(a), (c)(1), (c)(6), (c)(12). The 2020 NWPR disregards the 
significant nexus standard, see generally 85 FR 22270, 22338-39 (April 
21, 2020); 33 CFR 328.3, and, in doing so, restricted the scope of the 
statute using limitations Justice Kennedy viewed as anathema to the 
purpose and text of the Clean Water Act. For the reasons articulated 
throughout sections IV.A and IV.B of this preamble, the agencies reject 
the 2020 NWPR's interpretation of ``waters of the United States'' as 
inconsistent with the objective of the Clean Water Act, the science, 
and the case law.
    While the relatively permanent standard is administratively useful 
and includes waters that have important effects on the water quality of 
paragraph (a)(1) waters, the standard excludes waters that properly 
fall within the Clean Water Act's protections. As a result, this rule's 
incorporation of jurisdictional limitations based upon the relatively 
permanent standard and the significant nexus standard reflects the text 
of the statute as a whole. Thus, with this rule, the agencies properly 
fulfill their congressionally delegated responsibility to construe 
``waters of the United States'' in a manner that advances the objective 
of the Act.
iii. Fact-Based Standards for Determining Clean Water Act Jurisdiction 
Are Appropriate
    The agencies have the discretion to consider defining waters as 
jurisdictional on a categorical basis where scientifically and legally 
justified (for example in this rule, paragraph (a)(1) waters and their 
adjacent wetlands) or a case-specific, fact-based approach (for 
example, in this rule, tributaries and their adjacent wetlands that 
meet the significant nexus standard or relatively permanent standard). 
While the latter does not necessarily provide the same certainty as 
defining waters as jurisdictional by category, case-specific 
determinations of the scope of Clean Water Act jurisdiction are not 
unusual--in fact, they are the norm. In the Supreme Court's most recent 
decision addressing a question about the jurisdictional scope of the 
Clean Water Act, although not the scope of ``waters of the United 
States,'' the Court established a standard for determining jurisdiction 
that does not establish bright lines marking the bounds of Federal 
jurisdiction. Instead, like the significant nexus standard, the 
standard in Maui requires an inquiry focused on the specific facts at 
issue and is guided by the purposes Congress sought to achieve under 
the Clean Water Act. In Maui, the Supreme Court considered whether 
discharges to groundwater that reach navigable waters are 
jurisdictional under the Clean Water Act and thus subject to the Act's 
section 402 permitting program. The Court held that ``the statute 
requires a permit when there is a direct discharge from a point source 
into navigable waters or when there is the functional equivalent of a 
direct discharge.'' Maui, 140 S. Ct. at 1476. The Court explained that 
``[w]e think this phrase best captures, in broad terms, those 
circumstances in which Congress intended to require a federal permit.'' 
Id. The Court further explained that, in applying its broadly worded 
standard, ``[t]he object in a given scenario will be to advance, in a 
manner consistent with the statute's language, the statutory purposes 
that Congress sought to achieve.'' Id. The Court recognized that the 
difficulty with its approach was that ``it does not, on its own, 
clearly explain how to deal with middle instances,'' but reasoned that 
``there are too many potentially relevant factors applicable to 
factually different cases for this Court now to use more specific 
language.'' Id. The Court enumerated a series of factors relevant to 
determining whether a discharge is the ``functional equivalent'' of 
direct discharge, including the time between when the discharge occurs 
and when the pollutants reach the navigable water, the distance the 
pollutants travel to the navigable water, the nature of the material 
through which the pollutant travels, the extent to which the pollutant 
is diluted or chemically changed as it travels, the amount of pollutant 
entering the navigable waters relative to the amount of the pollutant 
that leaves the point source, the manner by or area in which the 
pollutant enters the navigable waters, and the degree to which the 
pollution (at that point) has maintained its specific identity. Id. at 
1476-77.
    The Supreme Court's ``functional equivalent'' standard has several 
key characteristics in common with the significant nexus standard and 
the agencies' approach in this rule. Both standards require an analysis 
focused on the specific facts at issue in a particular instance. Under 
the ``functional equivalent'' standard, factors that may be relevant, 
depending on the circumstances of a particular case, include transit 
time, distance traveled, the geologic substrate through which the 
discharges travels, the location and nature of the receiving water, and 
other factors. Similarly, the significant nexus standard requires 
consideration of scientific principles of upstream functions and 
effects on the integrity of paragraph (a)(1) waters and facts related 
to the specific waters at issue. Indeed, this rule includes a list of 
factors that would be considered when assessing whether waters 
significantly affect paragraph (a)(1) waters that is similar in nature 
to the factors identified by the Court that may be relevant to making a 
``functional equivalent'' assessment. See section IV.C.9 of this 
preamble. The relatively permanent standard also

[[Page 3043]]

requires inquiry into specific facts about particular tributaries, 
wetlands, and open waters, although the inquiry generally requires less 
information-gathering and assessment than the significant nexus 
standard. The Court in Maui also explicitly rejected EPA's suggested 
approach, which established a bright line that categorically excluded 
all discharges to groundwater regardless of whether they reached 
navigable waters and instead adopted the ``functional equivalent'' 
analysis. 140 S. Ct. at 1474-75. The Maui Court's analysis underscores 
the agencies' concerns about the 2020 NWPR, which categorically 
excluded all ephemeral tributaries and wetlands that did not meet its 
very narrow definition in spite of their impact on the chemical, 
physical, and biological integrity of paragraph (a)(1) waters. In this 
rule, the agencies are rejecting that approach and resuming the use of 
the significant nexus standard to determine which waters have a 
sufficient impact on traditional navigable waters, the territorial 
seas, or interstate waters.
    Finally, both the functional equivalent standard and the 
significant nexus standard should be applied while keeping in mind the 
purposes of the Clean Water Act. As the Court explained in Maui, 
``[t]he underlying statutory objectives also provide guidance. 
Decisions should not create serious risks either of undermining state 
regulation of groundwater or of creating loopholes that undermine the 
statute's basic federal regulatory objectives.'' Id. at 1477. Likewise, 
Justice Kennedy explained that, when assessing the existence of a 
``significant nexus'' between wetlands and navigable waters, ``[t]he 
required nexus must be assessed in terms of the statute's goals and 
purposes.'' Rapanos, 547 U.S. at 779.
    The agencies recognize that in both Rapanos and Maui, the Supreme 
Court was clear that the agencies could promulgate regulations that 
further refine the case-specific jurisdictional tests. With this rule, 
the agencies have established limits that appropriately draw the 
boundary of ``waters of the United States'' by ensuring that, where 
upstream waters significantly affect the integrity of waters and the 
Federal interest is indisputable--the traditional navigable waters, the 
territorial seas, and interstate waters--Clean Water Act programs apply 
to ensure that the downstream waters are adequately protected (by 
protecting those upstream waters). This rule continues the use of case-
specific jurisdictional tests but also provides needed clarity by 
establishing regulations that include definitions of key terms and 
specific exclusions. Moreover, the agencies have extensive experience 
making jurisdictional determinations using the relatively permanent 
standard and the significant nexus standard. Field staff have gained 
extensive familiarity and practical experience with the national and 
regionally specific field methods, literature, datasets, models, and 
tools that are required to make such determinations, resulting in 
increased efficiencies over time. See section IV.C.10 of this preamble. 
In addition, this rule increases clarity and implementability by 
streamlining and restructuring the 1986 regulations, and this preamble 
provides implementation guidance informed by sound science, 
implementation tools (including modern assessment tools), and other 
resources.
b. This Rule Reflects Full and Appropriate Consideration and Balancing 
of the Water Quality Objective in Section 101(a) and the Policies 
Relating to Responsibilities and Rights of Tribes and States Under 
Section 101(b) of the Clean Water Act
    This rule reflects consideration of the statute as a whole, 
including the objective of the Clean Water Act and the policies of the 
Act with respect to the role of Tribes and States. As discussed in 
section IV.A.2.a of this preamble, the agencies must consider the 
objective of the Clean Water Act in interpreting the scope of the 
statutory term ``waters of the United States.'' In this rule, the 
agencies also consider the entire statute, including section 101(b) of 
the Clean Water Act, which provides that it is congressional policy to 
preserve the primary responsibilities and rights of States ``to 
prevent, reduce, and eliminate pollution, to plan the development and 
use . . . of land and water resources, and to consult with the 
Administrator in the exercise of [the Administrator's] authority'' 
under the Clean Water Act. 33 U.S.C. 1251(b). Determining where to draw 
the boundaries of Federal jurisdiction to ensure that the agencies 
advance Congress's objective while preserving and protecting the 
responsibilities and rights of the States is a matter of judgment 
assigned by Congress to the agencies.
    The agencies find that this rule both advances the objective of the 
Clean Water Act in section 101(a) and respects the role of Tribes and 
States in section 101(b).\62\ The rule appropriately draws the boundary 
of waters subject to Federal protection by limiting the scope to the 
protection of upstream waters that significantly affect the integrity 
of waters where the Federal interest is indisputable--the traditional 
navigable waters, the territorial seas, and interstate waters. Waters 
that do not implicate the Federal interest in these paragraph (a)(1) 
waters are not included within the scope of Federal jurisdiction. The 
scope and boundaries of the definition therefore reflect the agencies' 
considered judgment of both the Clean Water Act's objective in section 
101(a) and the congressional policy relating to States' rights and 
responsibilities under section 101(b).
---------------------------------------------------------------------------

    \62\ While Clean Water Act section 101(b) does not specifically 
identify Tribes, the policy of preserving States' sovereign 
authority over land and water use is equally relevant to ensuring 
the primary authority of Tribes to address pollution and plan the 
development and use of Tribal land and water resources.
---------------------------------------------------------------------------

    The agencies have carefully considered sections 101(a) and 101(b) 
as well as the agencies' analysis and application of these provisions 
in promulgating the 2020 NWPR. In several key respects, the agencies' 
consideration and weighing of these provisions in this rulemaking 
differs from the agencies' approach in the 2020 NWPR. The agencies 
explained in the preamble to the proposed rule why the agencies' 
revised approach represents a fuller and more appropriate consideration 
of these provisions than reflected in the 2020 NWPR, and the agencies 
reaffirm those positions. 86 FR 69399 (December 7, 2021). As discussed 
below, based on the text of section 101(b), the structure of section 
101 and the Clean Water Act as a whole, Supreme Court precedent, and 
the history of Federal water pollution laws enacted by Congress up 
through the 1972 amendments, the construction of the Act in this rule 
fully and appropriately considers sections 101(a) and 101(b).
    The policy in section 101(b) is both important and relevant to the 
agencies' defining an appropriate scope of ``waters of the United 
States.'' Consistent with the text of the statute and as emphasized by 
the Supreme Court, Federal jurisdiction under the Clean Water Act has 
limits. As explained above, Clean Water Act jurisdiction encompasses 
(and is limited to) those waters that significantly affect the 
indisputable Federal interest in the protection of the paragraph (a)(1) 
waters--i.e., traditional navigable waters, the territorial seas, and 
interstate waters. And consistent with the section 101(b) policy, where 
protection (or degradation) of waters does not implicate this Federal 
interest, such waters fall exclusively within Tribal or

[[Page 3044]]

State regulatory authority should they choose to exercise it. However, 
there is no indication in any text of the statute that Congress 
established section 101(b) as the lynchpin of defining the scope of 
``waters of the United States.'' Rather, the Clean Water Act's 
objective--restoring and maintaining the chemical, physical, and 
biological integrity of the nation's waters--is set forth in the first 
words of the first section of the statute. And the statute is designed 
to address that objective through a ``comprehensive'' Federal program 
of pollution control. Indeed, the text of section 101(b) is actually a 
recognition of States' authority to ``prevent, reduce, and eliminate 
pollution'' and provide support for the Administrator's exercise of his 
or her authority to advance the objective of the Clean Water Act.
    The text of section 101(b) also expressly recognizes States' role 
in administering the Federal permitting programs under section 402 of 
the Clean Water Act:

    It is the policy of Congress that the States manage the 
construction grant program under this chapter and implement the 
permit programs under sections 1342 [402] and 1344 [404] of this 
title. It is further the policy of the Congress to support and aid 
research relating to the prevention, reduction, and elimination of 
pollution, and to provide Federal technical services and financial 
aid to State and interstate agencies and municipalities in 
connection with the prevention, reduction, and elimination of 
pollution.

    Thus, the text of section 101(b) as a whole does not reflect a 
general policy of deference to State regulation to the exclusion of 
Federal regulation, which would be inconsistent with Congress's 
enactment of the Clean Water Act because of the failures of a statutory 
scheme that relied primarily on State enforcement of State water 
quality standards. S. Rep. No. 92-414, 92d Cong., 1st Sess. 7 (1971) 
(observing that prior statutes had been ``inadequate in every vital 
aspect''). Instead, section 101(b) sets forth a policy focused on 
preserving the responsibilities and rights of States to work to achieve 
the objective of the Act. Those rights and responsibilities are to 
prevent, reduce, and eliminate pollution generally, including, but not 
limited to, through their authority over any source of pollution 
subject to State law, consulting with the Administrator in the exercise 
of his or her Clean Water Act authority, and implementing the Act's 
regulatory permitting programs, in partnership and with technical and 
financial support from the Federal Government.
    The agencies' interpretation and consideration of section 101(b) in 
this rule is consistent with Supreme Court precedent. The Supreme Court 
has described, on numerous occasions, section 101(b) as creating a 
partnership between the Federal and State governments in which the 
States administer programs under federally mandated standards and are 
allowed to set even more stringent standards. See, e.g., Arkansas v. 
Oklahoma, 503 U.S. 91, 101 (1992) (stating that the Act ``anticipates a 
partnership between the States and the Federal government'' to meet the 
``shared objective'' in section 101(a), with the Federal Government 
setting pollutant discharge limitations and States implementing water 
quality standards for their respective waterbodies); Int'l Paper Co. v. 
Ouellette, 479 U.S. 481, 489-90 (1987) (describing section 101(b) as 
allowing the Federal Government to delegate administration of point 
source pollution permits to States and allowing States to establish 
more stringent discharge limitations than Federal requirements); Train 
v. Colo. Pub. Interest Grp., 426 U.S. 1, 16 & n.13 (1976) (describing 
section 101(b) as providing States authority to develop permit programs 
and establish standards more stringent than those under the Clean Water 
Act); see also City of Milwaukee v. Illinois, 451 U.S. 304, 341 (1981) 
(Blackmun, J., dissenting) (describing section 101(b) as creating 
``shared authority between the Federal Government and the Individual 
States'' that allows for the States to set more stringent standards 
than necessary by Federal law). While this rule does not directly 
establish or alter a Clean Water Act program, these decisions informed 
the agencies' deliberations because the definition of ``waters of the 
United States'' affects the scope of Clean Water Act programs.
    The agencies have also carefully considered the policy in section 
101(b) as it relates to the Clean Water Act's objective in section 
101(a). The Clean Water Act's structure makes clear that section 101(a) 
sets forth the foundational purpose of the statute that must be 
achieved. First, section 101(a) is the opening section of the statute 
and is labelled the ``objective'' of the Clean Water Act. The agencies 
interpret its placement and its simple, declarative, and overarching 
statement as a powerful expression by Congress that merits substantial 
weight in defining the scope of jurisdiction for all of the Clean Water 
Act's regulatory programs. In contrast, section 101(b) is one of four 
congressional policies contained in section 101; the other three relate 
to seeking to ensure foreign countries take action to prevent, reduce, 
and eliminate pollution; reducing paperwork, duplication, and 
government delays; and State authority to allocate quantities of water 
within their jurisdictions. See 33 U.S.C. 1251(c), (f), (g). Just as 
none of those policies plays a central role in defining the scope of 
the Clean Water Act, neither should section 101(b) be given such 
prominence as to undermine Congress's stated objective. The prominently 
placed and single expression of the Clean Water Act's overarching 
objective in section 101(a) merits greater weight in the agencies' 
decision-making than any of the four congressional policies expressed 
in section 101 which, while important, appear subordinate to the 
objective--particularly given the statutory text and structure. To the 
extent there is ambiguity, the agencies have been delegated the 
authority to define ``waters of the United States'' and again conclude 
based on the statutory text and structure, and confirmed by the 
legislative history, that the overarching objective of the Act merits 
greater weight. The agencies have also thoroughly considered the other 
policies in section 101 of the Act, especially section 101(b) as 
discussed in this section of the preamble.
    The remainder of the Clean Water Act's text also demonstrates how 
important this objective was to Congress. In the Clean Water Act 
itself, Congress refers to the objective of the Act approximately a 
dozen times, including in sections 104, 105, 117, 120, 217, 301, 303, 
304, 305, 308, 319, 402, 516, 518, and 603. The repeated reference to 
the objective highlights the importance of the Clean Water Act's 
objective to the statute as a whole, supporting the agencies' giving 
substantial weight to this provision. Section 101(b), in contrast, is 
not referred to elsewhere in the Clean Water Act.
    Congress itself defined the contours of how it expected the 
agencies to both achieve its objective in section 101(a) and implement 
its policy in section 101(b) through the rest of the provisions of the 
Clean Water Act. Notably, a narrow definition of ``waters of the United 
States'' would not uniformly boost State authority as that definition 
is foundational to the scope of all of the Clean Water Act's programs, 
including those in which the States are assigned authority. Indeed, in 
implementing Clean Water Act regulatory requirements, States can have 
more powerful and holistic tools than they would have in implementing 
State-only laws and regulations. For example,

[[Page 3045]]

section 401 requires State certification for federally licensed 
projects within a State's borders. A narrow definition of ``waters of 
the United States'' would thus actually limit States' ability to 
protect waters within their borders. Similarly, a narrow definition 
would limit the ability of a State to provide input during the 
permitting process for out-of-state section 402 and 404 permits that 
may affect its waters. See 33 U.S.C. 1341, 1342(b), 1344(h)(1)(E).
    The agencies' careful balancing of section 101(a) and 101(b) in 
this rule is also informed by and consistent with the Court's decision 
in SWANCC, wherein the Court stated: ``Congress chose to `recognize, 
preserve, and protect the primary responsibilities and rights of States 
. . . to plan the development and use . . . of land and water 
resources. . . .' We thus read the statute as written to avoid the 
significant constitutional and federalism questions.'' 531 U.S. at 174 
(citing 33 U.S.C. 1251(b)). Justice Kennedy further explained in 
Rapanos: ``In SWANCC, by interpreting the Act to require a significant 
nexus with navigable waters, the Court avoided applications--those 
involving waters without a significant nexus--that appeared likely, as 
a category, to raise constitutional difficulties and federalism 
concerns.'' 547 U.S. at 776. Likewise here, this rule--by limiting 
jurisdiction only to those waters that significantly affect the 
integrity of waters where the Federal interest is indisputable 
(traditional navigable waters, the territorial seas, and interstate 
waters)--avoids constitutional and federalism concerns.
    Under the Commerce Clause, Congress can regulate: (1) the channels 
of interstate commerce; (2) persons or things in interstate commerce; 
and (3) activities that substantially affect interstate commerce. 
United States v. Lopez, 514 U.S. 549, 558-59 (1995). Regulation of 
``waters of the United States'' as interpreted by this rule is a valid 
exercise of Congress's power under at least the first Lopez category. 
It is a well-settled proposition that Congress's power to regulate 
channels of interstate commerce also includes the power to adopt 
``appropriate and needful control of activities and agencies which, 
though intrastate, affect that commerce.'' Rapanos, 547 U.S. at 782-83 
(citing Oklahoma ex rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 
525-26 (1941)). Traditional navigable waters are squarely within 
Congress's power to regulate under its authority over the channels of 
interstate commerce. And ``[i]t has long been settled that Congress has 
extensive authority over this Nation's waters under the Commerce 
Clause'' as channels of interstate commerce. See Kaiser Aetna v. United 
States, 444 U.S. 164, 173 (1979). Indeed, Congress has enacted 
``numerous laws touching interstate waters.'' City of Milwaukee, 406 
U.S. at 101. Congress has broad power to keep the channels of commerce 
free from injurious uses. See, e.g., Pierce Cnty. v. Guillen, 537 U.S. 
129, 146-47 (2003); Lopez, 514 U.S. at 558; Perez v. United States, 402 
U.S. 146, 150 (1971); Caminetti v. United States, 242 U.S. 470, 491 
(1917); The Lottery Case (Champion v. Ames), 188 U.S. 321, 346-47 
(1903). Thus, courts have recognized that the power over traditional 
navigable waters as channels of commerce includes ``the power to 
regulate waters to limit pollution, prevent obstructions to navigation, 
reduce flooding, and control watershed development.'' United States v. 
Hubenka, 438 F.3d 1026, 1032 (10th Cir. 2006) (citations omitted). As 
noted earlier, Congress directed that the Clean Water Act ``be given 
the broadest possible constitutional interpretation,'' S. Conf. Rep. 
No. 92-1236, 92d Cong., 2d Sess. 144 (1972), and the ``Commerce Clause 
[is] broad enough to permit congressional regulation of activities 
causing air or water pollution, or other environmental hazards that may 
have effects in more than one State.'' Hodel v. Va. Surface Mining & 
Reclamation Ass'n, 452 U.S. 264, 282 (1981). The Supreme Court has 
stated that the term ``navigable'' must be given some meaning in 
defining ``waters of the United States.'' SWANCC, 531 U.S. at 172; 
Rapanos, 547 U.S. at 779 (Kennedy, J., concurring in the judgment). The 
agencies' construction of the Clean Water Act does that by defining 
``waters of the United States'' to include traditional navigable 
waters, the territorial seas, and interstate waters, and those waters 
that significantly affect those waters. But while Congress was 
utilizing only one prong of its Commerce Clause authority, that prong 
is nevertheless broad. Indeed, ``there is no reason to believe Congress 
has less power over navigable waters than over other interstate 
channels,'' such that Congress cannot regulate non-navigable waters in 
order to protect water quality in traditional navigable waters. United 
States v. Deaton, 332 F.3d 698, 707 (4th Cir. 2003). This rule and the 
significant nexus standard are squarely within the prong of Commerce 
Clause authority that Congress utilized in enacting the Clean Water Act 
and within the authority Congress delegated to the agencies under the 
Act. Both the rule and the standard are based on protecting traditional 
navigable waters, the territorial seas, and interstate waters from the 
effects of upstream pollution.
    Finally, in considering sections 101(a) and 101(b) for purposes of 
interpreting the scope of ``waters of the United States,'' the agencies 
conclude that it is important to consider the statutory history that 
gave rise to this structure. Indeed, the agencies recognize that in 
passing the Federal Water Pollution Control Act Amendments of 1972, 
Congress was not acting on a blank slate--it was amending existing law 
that had primarily provided for States to establish water quality 
standards for a subset of waters. Water Quality Act of 1965, Public Law 
89-234, 79 Stat. 903 (1965). Congress found the previous statute's 
focus on States' establishment and administration of water quality 
standards insufficient for the task of upgrading and protecting the 
quality of America's waters because States were lagging in establishing 
such standards and there was ``an almost total lack of enforcement.'' 
S. Rep. 92-414 (1971) at 5. The Clean Water Act was enacted to address 
these shortcomings after ``two of the important rivers [in the Sixth] 
circuit, the Rouge River in Dearborn, Michigan, and the Cuyahoga River 
in Cleveland, Ohio, reached a point of pollution by flammable materials 
in the last ten years that they repeatedly caught fire.'' United 
States. v. Ashland Oil & Transp. Co., 504 F.2d 1317, 1326 (6th Cir. 
1974). With the 1972 amendments, Congress adopted an entirely new 
approach to water pollution control--a prohibition of discharges of 
pollutants unless authorized by the Clean Water Act and a new, 
comprehensive, Federal regulatory scheme grounded in technology-based 
effluent standards applied uniformly across industries of the same 
type. ``The Committee recommends the change to effluent limits as the 
best available mechanism to control water pollution. With effluent 
limits, the Administrator can require the best control technology.'' S. 
Rep. 92-414 at 8. Congress also viewed the prohibition on discharges of 
pollutants unless authorized under the Act as ``establish[ing] a direct 
link between the Federal government and each industrial source of 
discharge into the navigable waters.'' Id. Thus, Congress viewed the 
Clean Water Act as a change from previous laws that centered on States 
and State water quality standards to a system based on a prohibition of 
discharges of pollutants to waters unless permitted in accordance with 
a Federal regulatory scheme and technology standards established by 
EPA. Tribes

[[Page 3046]]

and States play a vital role in the implementation and enforcement of 
the Clean Water Act, and this rule does not change that framework. 
Instead, this rule reinforces that framework by establishing 
limitations that reflect careful consideration of how best to identify 
those waters for which Federal regulation is necessary to ensure the 
protection of the waters at the core of Congress's authority and 
interest and those for which it is not.
    In the context of the scope of ``waters of the United States,'' the 
Court stated that Congress ``intended to repudiate limits that had been 
placed on federal regulation by earlier water pollution control 
statutes and to exercise its powers under the Commerce Clause to 
regulate at least some waters that would not be deemed `navigable' 
under the classical understanding of that term.'' Riverside Bayview, 
474 U.S. at 133. More recently, the Supreme Court in Maui also noted 
that: ``Prior to the Act, Federal and State Governments regulated water 
pollution in large part by setting water quality standards. The Act 
restructures federal regulation by insisting that a person wishing to 
discharge any pollution into navigable waters first obtain EPA's 
permission to do so.'' 140 S. Ct. at 1468 (citations omitted).
    With respect to States' responsibilities and rights under section 
101(b), Justice Kennedy in Rapanos cited State amici briefs that 
``note[d], among other things, that the Act protects downstream States 
from out-of-state pollution that they cannot themselves regulate.'' 547 
U.S. at 777. Indeed, the Supreme Court has recognized that this is an 
important aspect of the Clean Water Act's passage. City of Milwaukee 
involved alleged discharges of inadequately treated sewage from 
Milwaukee, Wisconsin, sewer systems directly into Lake Michigan, which 
also borders Illinois. The City of Milwaukee Court noted that prior to 
passage of the Clean Water Act, these discharges would have had to be 
resolved through litigation, in which the courts must apply ``often 
vague and indeterminate nuisance concepts and maxims of equity 
jurisprudence.'' 451 U.S. at 317. The Clean Water Act, however, 
replaced this unpredictable and inefficient approach with ``a 
comprehensive regulatory program supervised by an expert administrative 
agency,'' id., including a ``uniform system of interstate water 
pollution regulation,'' Arkansas v. Oklahoma, 503 U.S. 91, 110 (1992).
    An overly narrow definition of jurisdictional waters would threaten 
a return to pre-1972 regime, would exclude from Federal protection 
waters that significantly affect paragraph (a)(1) waters, and would 
risk removing from the statutory scheme instances of interstate 
pollution the 1972 amendments were designed in part to address. 
Nationwide pollution controls are critical to protecting water quality 
in downstream States because downstream States have limited ability to 
control water pollution sources in upstream States. See Int'l Paper Co. 
v. Ouellette, 479 U.S. at 490-91. Several commenters stated that, under 
the 2020 NWPR, certain States were subject to harm from increased 
pollution flowing through interstate waters from upstream States. In 
addition, commenters noted that the water quality in States bordering 
the Great Lakes depended on adequate protection in other Great Lakes 
States, some of which removed clean water regulations following 
promulgation of the 2020 NWPR. The consequences of water pollution 
discharged in one State and flowing to another are also economic in 
nature. Such pollution also destroys or diminishes the value of water 
to ``public water supplies, propagation of fish and wildlife, 
recreational purposes, and agricultural, industrial, and other 
purposes'' protected by the Clean Water Act. 33 U.S.C. 1313(c)(2)(A).
    Moreover, an overly narrow definition of ``waters of the United 
States'' would substantially impinge upon States' responsibilities and 
rights under section 401 of the Clean Water Act. It is only through 
that provision of the Act that States have the authority to grant, 
deny, or waive certification of proposed Federal licenses or permits 
that may discharge into waters of the United States.
    By promulgating a rule interpreting the Clean Water Act to cover 
waters that meet the relatively permanent standard or the significant 
nexus standard, the agencies have appropriately construed the Act to 
protect those waters necessary to protect the integrity of traditional 
navigable waters, the territorial seas, and interstate waters, while 
leaving regulatory authority over all the waters that do not have the 
requisite connection to paragraph (a)(1) waters exclusively to the 
Tribes and States. This construction respects the statutory history 
that gave rise to the Clean Water Act and gives effect to the 
comprehensive nature of the Act, its objective, and the many programs 
and policies affected by the scope of ``waters of the United States'' 
designed to meet that objective. This definition also ensures that 
States have sole authority over waters that do not significantly affect 
the paragraph (a)(1) waters clearly protected by the Act.
    As discussed elsewhere, this rule defines ``waters of the United 
States'' to include tributaries, adjacent wetlands, and paragraph 
(a)(5) waters that meet the relatively permanent or significant nexus 
standards (see section IV.C of this preamble). This rule advances the 
Clean Water Act's objective by helping restore and maintain the 
chemical, physical, and biological integrity of traditional navigable 
waters, the territorial seas, and interstate waters--waters of 
longstanding and indisputable Federal interest--by protecting them from 
degradation of upstream waters that significantly affect them. At the 
same time, consistent with section 101(b), this rule recognizes, 
preserves, and protects the rights and responsibilities of Tribes and 
States by leaving within their purview all waters that do not 
significantly affect the paragraph (a)(1) waters of paramount Federal 
interest. The specific jurisdictional standards in this rule therefore 
bear a relationship to the nature and extent of the Federal and Tribal 
and State interests at play. This line-drawing highlights the agencies' 
deliberate and due consideration of sections 101(a) and 101(b) in 
developing this rule.
4. This Rule Is Both Generally Familiar and Implementable
    As described above in section IV.A of this preamble, the agencies 
in this rule are interpreting ``waters of the United States'' to mean 
the waters defined by the familiar 1986 regulations, with amendments to 
reflect the agencies' determination of the statutory limits on the 
scope of ``waters of the United States'' informed by the text of the 
relevant provisions of the Clean Water Act and the statute as a whole, 
the scientific record, relevant Supreme Court precedent, and the 
agencies' experience and technical expertise after more than 45 years 
of implementing the longstanding pre-2015 regulations defining ``waters 
of the United States.'' It also reflects consideration of extensive 
public comment.
    The agencies have extensive experience implementing the pre-2015 
regulatory regime, as described further below in this section, and this 
experience will assist the agencies in implementing this rule. The 
agencies' approach to implementation of the relatively permanent and 
significant nexus standards is broadly consistent with the pre-2015 
regulatory regime, but the agencies have clarified and refined both the 
regulatory text and the guidance on how the agencies intend to 
implement these standards in order to promote consistent Clean Water 
Act protections for waters. For additional

[[Page 3047]]

clarity, this rule includes a definition of ``significantly affect'' 
for purposes of applying the significant nexus standard. See section 
IV.C of this preamble.
    Additionally, the agencies are codifying the two familiar and 
longstanding exclusions from the definition of ``waters of the United 
States'' for prior converted cropland and waste treatment systems and 
adding exclusions for features that were generally considered non-
jurisdictional under the pre-2015 regulatory regime (see section IV.C.7 
of this preamble). The features excluded under this rule were excluded 
by regulation or generally considered non-jurisdictional in practice 
under the pre-2015 regulatory regime and each of the subsequent rules 
defining ``waters of the United States.''
    The agencies have extensive experience implementing the 1986 
regulations. Moreover, the scientific and technical information 
available to inform the significant nexus analysis and identify waters 
that meet the relatively permanent standard has also markedly improved 
over time and become more readily available since the agencies first 
started implementing both standards. See section IV.G of this preamble. 
Since the Court's decision in Rapanos, the agencies have gained more 
than a decade of experience implementing the 1986 regulations 
consistent with the relatively permanent standard and the significant 
nexus standard under three different presidential Administrations, 
beginning with the Rapanos Guidance issued in 2007. The agencies have 
continued to implement the 1986 regulations consistent with the Rapanos 
Guidance in response to court decisions.
    The agencies repromulgated the 1986 regulations in the 2019 Repeal 
Rule and implemented those rules nationwide until June 22, 2020, when 
the 2020 NWPR became effective. The agencies explained that with the 
2019 Repeal Rule, they intended to ``restore the regulatory text that 
existed prior to the 2015 Rule'' and that the agencies would 
``implement the pre-2015 Rule regulations informed by applicable agency 
guidance documents and consistent with Supreme Court decisions and 
longstanding agency practice.'' 84 FR 56626 (October 22, 2019). The 
agencies concluded that this approach ``will provide greater regulatory 
certainty and national consistency while the agencies consider public 
comments on the proposed [2020 NPWR].'' Id. at 56660. To further 
justify a return to the 1986 framework, the agencies noted that ``[t]he 
agencies, their co-regulators, and the regulated community are . . . 
familiar with the pre-2015 Rule regulatory regime and have amassed 
significant experience operating under those pre-existing regulations. 
Agency staff in particular have developed significant technical 
expertise in implementing the 1986 regulations.'' Id. The 2019 Repeal 
Rule would thus ``provide greater certainty by reinstating nationwide a 
longstanding regulatory framework that is familiar to and well-
understood by the agencies, States, Tribes, local governments, 
regulated entities, and the public.'' Id. at 56661. Indeed, in their 
comments to the 2019 Repeal Rule proposal, a number of regulators and 
regulated parties alike expressed support for returning to the pre-2015 
regulations, as implemented following SWANCC and Rapanos, due in part 
to their experience and familiarity with that regime.\63\
---------------------------------------------------------------------------

    \63\ See, e.g., comments submitted by American Water Works 
Association (August 13, 2018) (Docket ID: EPA-HQ-OW-2017-0203-
15559); comments submitted by North Dakota's Department of 
Agriculture (July 25, 2018) (Docket ID: EPA-HQ-OW-2017-0203-15541); 
comments submitted by the Office of the Governor of Utah (August 9, 
2018) (Docket ID: EPA-HQ-OW-2017-0203-15202) (``Recodification of 
the regulations that existed prior to the 2015 Rule will provide 
continuity and certainty for regulated entities, States, the 
agencies' staff, and the American public.'').
---------------------------------------------------------------------------

    Further, in responding to comments on the 2019 Repeal Rule proposal 
asserting that the agencies should not return to the pre-2015 
regulatory regime because that regime would reduce regulatory certainty 
due to the prior regime's reliance on case-specific significant nexus 
determinations, the agencies explained that ``[f]ollowing the Supreme 
Court's decisions in SWANCC and Rapanos . . . the Corps published a 
guidebook to assist district staff in issuing approved jurisdictional 
determinations. In particular, the guidebook outlines procedures and 
documentation used to support significant nexus determinations. This 
guidebook has been and continues to be publicly available and will 
continue to serve as a resource in issuing jurisdictional 
determinations under this final rule.'' \64\ 84 FR 56660 (October 22, 
2019). Even after the 2020 NWPR's June 22, 2020, effective date, the 
agencies continued to implement the 2019 Repeal Rule consistent with 
the Rapanos Guidance in Colorado until April 2021 due to litigation 
barring implementation of the 2020 NWPR in that State.
---------------------------------------------------------------------------

    \64\ For convenience, EPA decisions on jurisdiction are referred 
to as jurisdictional determinations throughout this document, but 
such decisions are not ``approved jurisdictional determinations'' as 
defined and governed by the Corps' regulations at 33 CFR 331.2.
---------------------------------------------------------------------------

    Like the past three presidential Administrations, courts have also 
found that the 1986 regulations, implemented consistent with the 
Rapanos standards, provide an appropriate regulatory framework to 
implement the Clean Water Act. Indeed, in staying the 2015 Clean Water 
Rule nationwide, the Sixth Circuit found that returning to the 
``familiar, if imperfect, pre-Rule regime'' was the best path forward 
pending judicial review of the 2015 Clean Water Rule. In re EPA & Dep't 
of Def. Final Rule, 803 F.3d 804, 808 (6th Cir. 2015), vacated, 713 
Fed. Appx. 489 (6th Cir. 2018). In doing so, the court recognized that 
returning to the status quo meant returning to the pre-2015 regulatory 
regime--not the 1986 regulations. See id. at 806 (finding that ``the 
status quo at issue is the pre-[2015 Clean Water Rule] regime of 
federal-state collaboration that has been in place for several years, 
following the Supreme Court's decision in Rapanos''). Likewise, in 
vacating the 2020 NWPR, the Arizona district court found that returning 
to the pre-2015 regulatory regime would provide for a regime that ``is 
familiar to the Agencies and industry alike.'' See Pascua Yaqui Tribe 
v. EPA, 557 F. Supp. 3d 949, 956 (D. Ariz. 2021).
    The agencies acknowledge that the need for case-specific analyses 
will continue under this rule for certain jurisdictional 
determinations, potentially raising some timeliness and consistency 
issues that the agencies' rules in 2015 and 2020 were designed, in 
part, to reduce. The agencies' experience suggests that the number of 
these analyses will be limited. Historically, only approximately 12% of 
resources assessed in approved jurisdictional determinations using the 
Rapanos Guidance required a significant nexus analysis.\65\ And those 
significant nexus assessments often resulted in a conclusion that the 
resource, either alone or in combination with similarly situated 
waters, did not meet the significant nexus standard. Moreover, the 
agencies have provided more clarity in this rule by: adding limitations 
to the scope of the definition to the rule text; adding a definition of 
``significantly affect'' that identifies the

[[Page 3048]]

functions and factors to be evaluated as part of a significant nexus 
analysis; adding exclusions to the rule; restructuring and streamlining 
the 1986 regulations; and drawing on more than a decade of post-Rapanos 
implementation experience to provide additional implementation guidance 
and resources. These improvements, taken together, substantially reduce 
any inefficiencies that may be presented by the rule's case-specific 
approach. Finally, as discussed above, the nature of the Clean Water 
Act's requirements in general can be a fact-based, case-specific 
inquiry and is not limited to whether a water meets the definition of 
``waters of the United States.'' The inquiry is an important one, for 
both discharges and the environment.
---------------------------------------------------------------------------

    \65\ It is the agencies' expectation that the number of 
significant nexus analyses will increase under this rule due to the 
assessment of paragraph (a)(5) waters under the significant nexus 
standard, but the agencies do not expect a corresponding increase in 
positive jurisdictional determinations. See section IV.C.6 of this 
preamble for discussion of the agencies' intentions for 
implementation of paragraph (a)(5).
---------------------------------------------------------------------------

    This rule is both consistent with the Clean Water Act's statutory 
text and purposes and its framework is longstanding and familiar to 
regulated parties and regulators alike. Moreover, all definitions of 
``waters of the United States,'' including the 2020 NWPR, require some 
level of case-specific analysis. Implementation of this rule will be 
aided by improved and increased scientific and technical information 
and tools that both the agencies and the public can use to determine 
whether waters are ``waters of the United States'' (see section IV.G of 
this preamble). Accordingly, the agencies have concluded that this rule 
is consistent with the Clean Water Act and that its clarity and 
familiar regulatory framework improve its implementability.
    Through the various rulemakings and court decisions relating to the 
definition of ``waters of the United States'' since the Rapanos 
decision in 2006, the agencies have continued implementing the 1986 
regulations consistent with the Rapanos standards nationwide or in 
numerous States across the country for various periods of time, 
learning as they did so. This experience has allowed the agencies to 
further develop expertise in implementing this regime. The agencies, 
most often the Corps, have made hundreds of thousands of Clean Water 
Act approved jurisdictional determinations since the issuance of the 
Rapanos Guidance. Of those, tens of thousands have required a case-
specific significant nexus determination. The agencies have made such 
determinations in every State in the country as well as in the U.S. 
territories.
    With field staff located in 38 Corps District offices and 10 EPA 
regional offices, the agencies have over a decade of nationwide 
experience in making decisions regarding jurisdiction under the pre-
2015 regulatory regime consistent with the relatively permanent 
standard and the significant nexus standard. Significant nexus 
determinations have been made affirmatively for waters ranging from an 
ephemeral stream that flows directly into a traditional navigable water 
used extensively for recreational boating and fishing, to wetlands 
adjacent to a perennial tributary and separated by a levee, to a non-
relatively permanent stream that provides flow to a drinking water 
source, to a group of floodplain wetlands that provide important 
protection from floodwaters to downstream communities alongside the 
traditional navigable water, to headwater mountain streams that provide 
high quality water that supplies baseflow and reduces the harmful 
concentrations of pollutants in the main part of the river below. The 
agencies have also made many findings of no jurisdiction under the 1986 
regulations when they concluded the waters in question did not meet 
either the relatively permanent standard or the significant nexus 
standard as implemented by the Rapanos Guidance.
    Through this experience, the agencies developed wide-ranging 
technical expertise in assessing the hydrologic flowpaths along which 
water and materials are transported and transformed and that determine 
the degree of chemical, physical, or biological connectivity and 
effects to paragraph (a)(1) waters. The agencies have also become 
deeply familiar with the variations in climate, geology, and terrain 
within and among watersheds that affect the functions (such as the 
transformation or filtering of pollutants) performed by streams, open 
waters, and wetlands for paragraph (a)(1) waters.
    The agencies utilize many tools and many sources of information to 
help support decisions on jurisdiction, including U.S. Geological 
Survey (USGS) and State and local topographic maps, aerial photography, 
satellite imagery, gage data, soil surveys, National Wetlands Inventory 
maps, floodplain maps, watershed studies, modeling tools, scientific 
literature and references, and field work. As discussed further in 
section IV.G of this preamble, these tools have undergone important 
technological advances and have become increasingly available since the 
Rapanos decision. For example, USGS, State, and local stream maps and 
datasets, aerial photography, gage data, watershed assessments, 
monitoring data, and field observations are often used to help assess 
the flow contributions of tributaries, including intermittent and 
ephemeral streams, to downstream traditional navigable waters, the 
territorial seas, or interstate waters. Similarly, floodplain and 
topographic maps from Federal, State, and local agencies, modeling 
tools, and field observations can be used to assess how wetlands are 
storing floodwaters that might otherwise affect the integrity of 
paragraph (a)(1) waters. Further, the agencies utilize the large body 
of scientific literature regarding the functions of tributaries, 
including tributaries with ephemeral, intermittent, and perennial flow, 
and of wetlands and open waters to inform their significant nexus 
analyses. In addition, the agencies have experience and expertise from 
decades of making decisions on jurisdiction that considered hydrology, 
ordinary high water mark (OHWM) and its associated indicators (see 
section IV.C.8.d of this preamble), biota, and other technical factors 
in implementing Clean Water Act programs. The agencies' immersion in 
the science, along with the practical expertise developed over more 
than a decade of case-specific determinations across the country, have 
helped the agencies determine which waters have a significant nexus and 
where to draw boundaries demarking the ``waters of the United States.''
    Regulated entities and other interested parties also have 
substantial experience with the 1986 regulations and the two Rapanos 
standards. As the agencies have developed their expertise in 
implementing this regime, so have State and Tribal co-regulators and 
regulated entities, as well as interested citizens who may play an 
important role in the Act's permitting process. Individuals uncertain 
about the status of waters on their property may obtain a 
jurisdictional determination from the Corps. The Corps does not charge 
a fee for this service. See 33 CFR 325.1; Regulatory Guidance Letter 
16-01 (2016).
    Due in part to the familiarity of this regime, this rule will not 
undermine serious reliance interests in an alternative regime, 
including the 2020 NWPR, which the agencies have not implemented for 
over a year following the Arizona district court's August 30, 2021 
vacatur order. The Supreme Court has held that agencies' changes in 
position do not require any reasons ``more substantial than those 
required to adopt a policy in the first instance.'' FCC v. Fox 
Television Stations, Inc., 556 U.S. 502, 514 (2009). The Court 
acknowledged that if an agency's ``prior policy has engendered serious 
reliance interests,'' id. at 515, those interests cannot be ignored. 
However, the Court emphasized that even in the case of ``serious 
reliance interests,'' ``further

[[Page 3049]]

justification'' beyond a ``reasoned explanation . . . for disregarding 
facts and circumstances that underlay or were engendered by the prior 
policy'' is not needed. Id. at 515-16. This rule does not implicate 
serious reliance interests because, first, the agencies are codifying a 
rule similar to the definition currently being implemented nationwide. 
As discussed in section V.A of this preamble, this rule will establish 
a regime that is generally comparable to current practice, and this 
rule is expected to generate de minimis costs and benefits as compared 
to the pre-2015 regulatory regime that the agencies are currently 
implementing. Second, members of the public, Tribes, and States have 
been aware that the agencies might reconsider the 2020 NWPR since 
January 2021 and have had many opportunities to share their views with 
the agencies. President Biden indicated on his first day in office, 
following the issuance of Executive Order 13990, that this 
administration would be reviewing the 2020 NWPR and deciding whether to 
revise or replace the rule. See section III.B.5 of this preamble. On 
June 9, 2021, the agencies announced their intention to revise or 
replace the rule. The agencies subsequently embarked on an extensive 
stakeholder outreach process, including public meetings and federalism 
and Tribal consultations. See section III.C of this preamble. The 
agencies received over 32,000 recommendation letters from the public 
during pre-proposal outreach and over 114,000 comments on the proposed 
rule during the public comment period. The agencies also held a public 
hearing and multiple listening sessions with Tribal, State, and local 
governments during the public comment period to listen to feedback on 
the proposed rule from co-regulators and a variety of stakeholders.
    Third, the 2020 NWPR was only in effect for approximately 14 months 
before it was vacated by the Arizona district court on August 30, 2021. 
See Pascua Yaqui Tribe v. EPA, 557 F. Supp. 3d 949 (D. Ariz. 2021). 
Less than a month later, another district court issued an order 
vacating the 2020 NWPR on September 27, 2021. Navajo Nation v. Regan, 
563 F. Supp. 3d 1164 (D.N.M. 2021). And several other district courts 
remanded the 2020 NWPR without vacatur or without addressing vacatur in 
six additional cases, starting in July 2021.\66\ Following the vacatur 
orders, the agencies clarified that the Corps will no longer rely on 
approved jurisdictional determinations issued under the 2020 NWPR in 
making new permit decisions--although so-called ``stand-alone'' 
approved jurisdictional determinations (i.e., those that are not 
associated with a permit action) will not be reopened prior to their 
expiration date unless one of the criteria for revision is met or if 
the recipient requests that the Corps provide a new approved 
jurisdictional determination. See section IV.F of this preamble for 
further discussion of the status of approved jurisdictional 
determinations issued under prior rules.
---------------------------------------------------------------------------

    \66\ Order, Pueblo of Laguna v. Regan, No. 1:21-cv-00277, ECF 
No. 40 (D.N.M. Sept. 21, 2021) (declining to reach issue of vacatur 
in light of the Pascua decision); Order, California v. Wheeler, No. 
3:20-cv-03005, ECF No. 271 (N.D. Cal. Sept. 16, 2021) (same); Order, 
Waterkeeper All., Inc. v. Regan, No. 3:18-cv-03521, ECF No. 125 
(N.D. Cal. Sept. 16, 2021) (same); Order, Conservation L. Found. v. 
EPA, No. 1:20-cv-10820, ECF No. 122 (D. Mass. Sept. 1, 2021) (same); 
Order, S.C. Coastal Conservation League v. Regan, No. 2:20-cv-01687, 
ECF No. 147 (D.S.C. July 15, 2021) (remanding without vacating); 
Order, Murray v. Wheeler, No. 1:19-cv-01498, ECF No. 46 (N.D.N.Y. 
Sept. 7, 2021) (same).
---------------------------------------------------------------------------

    Interested parties have thus had over a year to adapt to operating 
under the pre-2015 regulatory regime in the absence of the 2020 NWPR, 
including ample notice of the implications of the 2020 NWPR's vacatur 
on the validity of approved jurisdictional determinations issued 
thereunder. Moreover, as discussed in this section, members of the 
public are familiar with this rule's regulatory framework thereby 
minimizing the potential disruption of a change. Finally, even if 
serious reliance interests were at issue, which they are not, this rule 
provides a thorough and reasoned explanation for the changed definition 
of ``waters of the United States.''
5. Public Comments Received and Agency Responses
    The agencies received numerous comments on the basis for the 
proposed rule, including comments about the proposal's consistency with 
the statute and Supreme Court decisions and about the proposal's 
approach to various categories of waters. The agencies have fully 
considered these timely comments and made changes to the rule to 
reflect the comments, as discussed below. This section contains 
summaries of these comments and the agencies' general responses; a more 
comprehensive response to these comments is in the response to comments 
document available in the docket for this rule at Docket ID No. EPA-HQ-
OW-2021-0602.
a. Comments Regarding Consistency of the Proposed Rule With the Text of 
the Clean Water Act
    Many commenters stated that the proposed rule is consistent with 
the Clean Water Act's objective in section 101(a) to restore and 
maintain the chemical, physical, and biological integrity of the 
nation's waters and provided multiple reasons to support that view, 
including the statutory text, legislative history, and science. Some 
commenters further asserted that the statute requires the agencies to 
regulate waters in addition to traditional navigable waters, the 
territorial seas, and interstate waters.
    The agencies agree that the definition of ``waters of the United 
States'' must be designed to advance the objective of the Clean Water 
Act. For the reasons discussed in section IV.A.2 and IV.A.3 of this 
preamble, the agencies also interpret the Act based on factors other 
than the science and connectivity of waters, including the text of the 
statute as a whole and relevant Supreme Court decisions. Further, while 
the definition of ``waters of the United States'' is designed to 
advance the objective of restoring and maintaining the chemical, 
physical, and biological integrity of traditional navigable waters, the 
territorial seas, and interstate waters--i.e., the paragraph (a)(1) 
waters--this rule covers additional waters that must be protected to 
safeguard paragraph (a)(1) waters. All ``waters of the United States'' 
receive the full protections of the Clean Water Act.
    Commenters expressed various views on the import of the word 
``navigable'' in the statutory term ``navigable waters.'' Some 
commenters asserted that the proposed rule did not give enough effect 
to the word ``navigable,'' while others suggested that the agencies' 
jurisdiction over ``waters of the United States'' is limited to 
traditional navigable waters. Further, some commenters stated that 
Congress intended to exercise only its traditional commerce power over 
navigation rather than the full extent of its authority under the 
Commerce Clause. In contrast, other commenters asserted that 
legislative history demonstrates Congress's intent to assert broad 
jurisdiction under the Clean Water Act beyond navigable-in-fact waters.
    The agencies agree that while the Clean Water Act applies to 
``navigable waters,'' Congress also broadly defined that term to 
include ``the waters of the United States.'' 33 U.S.C. 1362(7). The 
breadth of that definition reflects a deliberate choice. The relevant 
House bill would have defined ``navigable

[[Page 3050]]

waters'' as the ``navigable waters of the United States, including the 
territorial seas.'' H.R. Rep. No. 92-911, 92d Cong., 2d Sess. 356 
(1972). But in conference the word ``navigable'' was deleted from that 
definition, and the conference report urged that the term ``be given 
the broadest possible constitutional interpretation.'' S. Conf. Rep. 
No. 92-1236, 92d Cong., 2d Sess. 144 (1972). Additionally, the agencies 
disagree that Clean Water Act jurisdiction is limited to traditional 
navigable waters, as this interpretation would render the Clean Water 
Act narrower than the Rivers and Harbors Act of 1899. Limiting Clean 
Water Act jurisdiction to traditional navigable waters is also contrary 
to the views of all nine Supreme Court Justices in Rapanos and would 
undo Congress's considered and deliberate choice to expand Clean Water 
Act jurisdiction beyond traditional navigable waters because it found 
the prior statutes limited to those waters insufficient. Indeed, the 
Rapanos plurality recognized that a wetland may be treated as a covered 
water if it has a continuous surface connection to a ``relatively 
permanent'' tributary that ``connect[s] to'' traditional navigable 
waters, without any further inquiry into the tributary's navigability 
or status as a link in a channel of commerce. 547 U.S. at 742. The 
plurality further observed that the 1977 Clean Water Act's 
authorization for States to administer the section 404 program for 
``navigable waters . . . other than'' those used or suitable for use 
``to transport interstate or foreign commerce,'' id. at 731 (quoting 33 
U.S.C. 1344(g)(1)), ``shows that the Act's term `navigable waters' 
includes something more than traditional navigable waters.'' Id. 
(citing SWANCC, 531 U.S. at 167; Riverside Bayview, 474 U.S. at 133). 
And neither Justice Kennedy nor the dissenting Justices in Rapanos 
endorsed such a jurisdictional limitation. See id. at 782-83 (Kennedy, 
J., concurring in the judgment); id. at 807-08 (Stevens, J., 
dissenting).
    The agencies are mindful of the Supreme Court's decision in SWANCC 
regarding the specific Commerce Clause authority Congress exercised in 
enacting the Clean Water Act. The SWANCC Court observed that Congress 
signified its intent to exercise its commerce power over navigation 
with the statement in the Conference Report for the Clean Water Act 
that the conferees ``intend that the term `navigable waters' be given 
the broadest possible constitutional interpretation.'' 531 U.S. at 168 
n.3 (citing S. Conf. Rep. No. 92-1236, at 144 (1972)). This rule 
ensures that waters that either alone or in combination significantly 
affect the integrity of traditional navigable waters, the territorial 
seas, or interstate waters are protected under the Clean Water Act, and 
the Supreme Court has long held that authority over traditional 
navigable waters is not limited to either protection of navigation or 
authority over only the traditional navigable water. Rather, the Court 
has found that ``the authority of the United States is the regulation 
of commerce on its waters . . . [f]lood protection, watershed 
development, [and] recovery of the cost of improvements through 
utilization of power are likewise parts of commerce control.'' United 
States v. Appalachian Elec. Power Co., 311 U.S. 377, 426 (1940); see 
also Oklahoma ex rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 
525-26 (1941) (``[J]ust as control over the non-navigable parts of a 
river may be essential or desirable in the interests of the navigable 
portions, so may the key to flood control on a navigable stream be 
found in whole or in part in flood control on its tributaries. . . . 
[T]he exercise of the granted power of Congress to regulate interstate 
commerce may be aided by appropriate and needful control of activities 
and agencies which, though intrastate, affect that commerce.'' 
(citations omitted)). The significant nexus standard included in this 
final rule ensures that the definition of ``waters of the United 
States'' remains well within the bounds of the Commerce Clause, 
consistent with the text of the statute and the intent of Congress, and 
informed by the decision in SWANCC.
    Some commenters suggested that the agencies cannot rely on the 
Clean Water Act's statutory objective or on science to expand Federal 
jurisdiction beyond the authority granted to the agencies by Congress. 
However, this final rule does not establish jurisdiction beyond the 
scope of the Clean Water Act. Indeed, as discussed in section IV.A of 
this preamble, the agencies conclude that the objective of the Clean 
Water Act must be considered in defining ``waters of the United 
States'' and that consideration of the objective of the Act for 
purposes of a rule defining ``waters of the United States'' must 
include substantive consideration of the effects of a revised 
definition on the integrity of the nation's waters. And since the 
objective of the Clean Water Act is to protect the water quality of the 
nation's waters, this rule must be informed by science relevant to 
water quality, as discussed in section IV.A.2.a of this preamble. At 
the same time, the agencies do not interpret the objective of the Clean 
Water Act to be the only factor relevant to determining the scope of 
the Act; rather, the limitations established in this rule are based on 
the agencies' consideration of the text of the relevant provisions of 
the Clean Water Act and the statute as a whole, the scientific record, 
relevant Supreme Court case law, and the agencies' experience and 
technical expertise after more than 45 years of implementing the 
longstanding pre-2015 regulations defining ``waters of the United 
States.'' The agencies thus have established a definition of ``waters 
of the United States'' within the authority granted to the agencies by 
Congress.
    Commenters also expressed various views about the import of Clean 
Water Act section 101(b). Some commenters asserted that the agencies 
must read sections 101(a) and 101(b) of the Clean Water Act together in 
a manner that recognizes States' traditional authority over their water 
resources and contended that the agencies did not adequately consider 
section 101(b) in developing the proposed rule. In contrast, other 
commenters asserted that section 101(b) is not intended to serve as a 
limit on Federal jurisdiction, and some of these commenters further 
suggested that the agencies improperly relied on section 101(b) to 
limit the scope of ``waters of the United States'' in the proposed 
rule. As discussed in section IV.A of this preamble and section V.A of 
the preamble to the proposed rule, the agencies have carefully, and 
appropriately, balanced consideration of sections 101(a) and 101(b) in 
deciding in the rulemaking which waters are subject to Clean Water Act 
jurisdiction.
    Additionally, multiple commenters asserted that a water that is not 
subject to Federal jurisdiction does not necessarily lack environmental 
protections because such waters may be subject to Tribal, State, or 
local regulations. Relatedly, some commenters suggested that improving 
and maintaining water quality is best achieved through partnerships and 
that the agencies should work with State and local governments in 
developing a definition of ``waters of the United States.'' The 
agencies recognize that waters that are not jurisdictional under the 
Clean Water Act do not necessarily lack environmental protections under 
potential Tribal, State, or local laws. However, Congress enacted the 
Clean Water Act precisely because of the failures of a statutory scheme 
that relied primarily on State water quality standards. In 1948, 
Congress enacted the Federal Water Pollution Control Act, ch.

[[Page 3051]]

758, 62 Stat. 1155 (June 30, 1948), which focused on State water 
quality standards rather than the conduct of individual polluters. See 
EPA v. California ex rel. State Water Res. Control Bd., 426 U.S. 200, 
202-03 (1976). In 1972, Congress enacted the Clean Water Act after 
concluding that these prior efforts had been ``inadequate in every 
vital aspect.'' S. Rep. No. 414, 92d Cong., 1st Sess. 7 (1971). The 
Clean Water Act was a `` `complete rewriting' '' of existing law, 
designed to ``establish an all-encompassing program of water pollution 
regulation.'' City of Milwaukee, 451 U.S at 317-18 (1981) (citation 
omitted).
    More recently, the Supreme Court in Maui identified a key dividing 
line between the areas where Congress intended to create a 
comprehensive floor of Federal water quality protections and those 
areas generally left to the States, observing that ``the structure of 
the [Clean Water Act] indicates that, as to groundwater pollution and 
nonpoint source pollution, Congress intended to leave substantial 
responsibility and autonomy to the States.'' 140 S. Ct. at 1471 (citing 
Clean Water Act section 101(b)). The Clean Water Act thus sets a 
baseline of Federal protection for waters that meet the definition of 
``waters of the United States'' and authorizes States to be more 
protective than the Act while also leaving substantial responsibility 
and autonomy to the States over those waters that do not have a 
significant nexus to the core waters covered by the Act. The agencies 
also agree that partnerships with Tribes, States, and local governments 
are important and can help facilitate meeting the objective of the Act 
and have coordinated with these entities over the course of this 
rulemaking to ensure that they had opportunities to provide input on 
this rule and will continue to work with Tribes and States to implement 
this rule.
b. Comments Regarding Supreme Court Case Law and the Significant Nexus 
and Relatively Permanent Standards
    Many commenters addressed the legal standard for determining the 
controlling opinion in Rapanos. In particular, many commenters cited 
Marks v. United States, 430 U.S. 188 (1977) to support assertions 
around what controlling legal principles may be derived from the 
opinion of five or more Supreme Court Justices when there is no 
majority. Relying on Marks, some of these commenters asserted that the 
Rapanos plurality opinion should control the definition of ``waters of 
the United States,'' while other commenters stated that Marks allows 
for use of either the plurality's relatively permanent standard or 
Justice Kennedy's significant nexus standard to assess Clean Water Act 
jurisdiction. As discussed above, the applicability of Marks is not the 
relevant inquiry for purposes of this rule. Rather, this rule reflects 
the agencies' interpretation of the statute, informed by Supreme Court 
precedent, not an interpretation of the Rapanos decision.
    The agencies received many comments on the proposed rule's reliance 
on and approach to the significant nexus standard. As explained in 
section IV.A.3.a of this preamble, the agencies have concluded that the 
significant nexus standard is consistent with the statutory text and 
legislative history, advances the objective of the Clean Water Act, is 
informed by the scientific record and Supreme Court case law, and 
appropriately considers the policies of the Act. The agencies have the 
authority to define the scope of the term ``navigable waters,'' and 
they are exercising that authority in this rule. A principal advantage 
of the significant nexus standard is that it focuses directly and 
specifically on protecting the integrity of those waters in which the 
Federal interest is indisputable--traditional navigable waters, the 
territorial seas, and interstate waters. Further, while the agencies 
disagree that this rule's significant nexus standard is inconsistent 
with Justice Kennedy's concurring opinion in Rapanos (as some 
commenters had suggested), this rule represents the agencies' 
interpretation of the statute, not an interpretation of Rapanos. The 
agencies have concluded that the significant nexus standard as 
established in this rule is the best interpretation of the statute and 
that the relatively permanent standard in the rule provides important 
efficiencies and additional clarity for regulators and the public. 
Thus, the rule gives effect to the Clean Water Act's broad terms and 
environmentally protective aim as well as its limitations.
    Some commenters suggested that the significant nexus standard is 
unclear or produces inconsistent results. In response to this concern, 
the agencies have established a definition of ``significantly affect'' 
in this rule, provided additional guidance on applying the significant 
nexus standard, and identified implementation tools and resources that 
will work together to provide clarity and further consistency in 
implementing the significant nexus standard (see section IV.C.9 and 
section IV.G of this preamble). The agencies have concluded that these 
actions, along with the agencies' extensive experience making 
determinations under the significant nexus standard, will increase the 
clarity and consistency of determinations of jurisdiction.
    Several commenters discussed whether the proposed rule is 
consistent with Justice Scalia's plurality opinion in Rapanos and 
expressed various views about the proper interpretation of that 
opinion. As discussed in section IV.A.3.a of this preamble, the 
agencies have concluded that use of the plurality's approach alone has 
no grounding in the Clean Water Act's text, structure, or history and 
would upend an understanding of the Act's coverage that has prevailed 
for decades. Similarly, no Court of Appeals has held that the 
plurality's relatively permanent standard is the sole test that may be 
used to establish Clean Water Act jurisdiction. Additionally, requiring 
a continuous surface water connection, as suggested by some commenters, 
would add a requirement and language that do not exist in the text of 
the plurality opinion. The plurality opinion states that ``continuous 
surface connection'' is a ``physical-connection requirement.'' Rapanos, 
547 U.S. at 742, 751 n.13 (referring to ``our [the plurality's] 
physical-connection requirement'' and asserting that Riverside Bayview 
does not reject ``the physical-connection requirement''). The plurality 
does not state that this standard is a continuous surface water 
requirement. Therefore, the agencies disagree that their longstanding 
implementation of the continuous surface connection requirement (see 
Rapanos Guidance at 7 n.28), which does not require a continuous flow 
of water between the wetland and the jurisdictional water, is 
inconsistent with the plurality opinion. In addition, a continuous 
surface water connection for wetlands is illogical when many wetlands 
have surface water only seasonally or intermittently or meet the 
wetland hydrology factor through saturated soils, a high water table, 
or other indicators of hydrology, and no scientific or regulatory 
definition of wetlands demands year-round surface water. See, e.g., 33 
CFR 328.3(b) (2008); NRC Report 3-5; see also 85 FR 22309 (explaining 
that ``not all abutting wetlands display surface water as the wetland 
hydrology factor but rather may have saturated soils, a high water 
table, or other indicators of hydrology''). See section IV.C.5.c.ii of 
this preamble for further discussion of the basis for the agencies' 
implementation of the continuous surface connection requirement in this 
rule.
    Additionally, multiple commenters suggested that the relatively 
permanent

[[Page 3052]]

standard is easier to apply than the significant nexus standard. While 
the agencies recognize that the relatively permanent standard can be 
easier to apply in many instances, that is not always the case. For 
example, in the case of a tributary that flows directly into a 
traditional navigable water, it may be easier to demonstrate that the 
tributary significantly affects the chemical, physical, or biological 
integrity of that paragraph (a)(1) water due to its direct contribution 
of flow, woody debris, and other materials and its close distance to 
the traditional navigable water than it would be to demonstrate that 
the flow in that tributary meets the relatively permanent standard. 
More importantly, greater simplicity that comes at the expense of a 
profound mismatch with the Clean Water Act's design is not a valid 
basis for determining the jurisdictional scope of the Act. Cf. Maui, 
140 S. Ct. at 1470, 1476 (rejecting similar arguments about a need for 
bright-line certainty in favor of a fact-specific test). Further, 
treating the relatively permanent standard as the exclusive criterion 
for Clean Water Act coverage would lead to arbitrary and illogical 
results. The 2020 NWPR did rely primarily on the relatively permanent 
standard and, in doing so, introduced new implementation uncertainties, 
including uncertainties related to the rule's case-specific typical 
year analysis, which the 2020 NWPR required for most categories of 
jurisdictional waters and that proved challenging to implement and 
yielded arbitrary results (see section III.B.3 and IV.B.3 of this 
preamble). In contrast, as discussed above, the agencies now have over 
a decade of nationwide experience with the significant nexus standard, 
and it has proven to be eminently administrable. Moreover, the agencies 
have made changes to this rule to increase the ease of implementation 
of the significant nexus standard.
    Commenters also provided a variety of views on the consistency of 
the proposed rule with the SWANCC Supreme Court decision. Some 
commenters expressed concern that the proposed rule would expand 
Federal jurisdiction over potentially all State waters, contrary to the 
Supreme Court's holding in SWANCC that--absent a clear statement from 
Congress--the Clean Water Act must be construed in a manner that avoids 
federalism and constitutional questions. The agencies disagree that 
this rule is contrary to the Supreme Court's holding in SWANCC and note 
that a principal advantage of the significant nexus standard is that it 
focuses directly and specifically on protecting traditional navigable 
waters, the territorial seas, and interstate waters. By design, the 
significant nexus standard thereby permits jurisdiction over waters 
only if they significantly affect the waters over which Congress has 
unquestioned authority. See, e.g., United States v. Lopez, 514 U.S. 
549, 558-59 (1995); Hodel v. Va. Surface Mining & Reclamation Ass'n, 
452 U.S. 264, 282 (1981). Thus, an affirmative finding under the 
significant nexus standard is, by definition, a finding that Congress's 
core purpose is implicated. Commenters' constitutional concerns are 
therefore fully addressed by this rule.
    In addition, a few commenters asserted that the Supreme Court in 
SWANCC rejected the notion that a biological or ecological connection 
alone is sufficient to support a finding of significant nexus. This 
reading of SWANCC is not correct. The Court in SWANCC did not hold that 
the particular ``ecological considerations upon which the Corps relied 
in Riverside Bayview,'' Rapanos, 547 U.S. at 741--i.e., the potential 
importance of wetlands to the quality of adjacent waters--were 
irrelevant to Clean Water Act jurisdiction. Rather, the Court held that 
a different ecological concern--namely, the potential use of the 
isolated ponds as habitat for migratory birds--could not justify 
treating those ponds as ``waters of the United States.'' See SWANCC, 
531 U.S. at 164-65, 171-72. The Court found that this specific 
ecological concern was not cognizable because it was unrelated to 
``what Congress had in mind as its authority for enacting the CWA: its 
traditional jurisdiction over waters that were or had been navigable in 
fact or which could reasonably be so made.'' Id. at 172. In contrast, 
in this rule, the agencies, through application of the significant 
nexus standard, provide Federal protections for adjacent wetlands and 
other categories of waters based on their importance to the chemical, 
physical, or biological integrity of traditional navigable waters, the 
territorial seas, and interstate waters. In addition, the objective of 
the Clean Water Act is ``to restore and maintain the chemical, 
physical, and biological integrity of the Nation's waters.'' 33 U.S.C. 
1251(a) (emphasis added). Among the means to achieve the Clean Water 
Act's objective, Congress established an interim national goal to 
achieve wherever possible ``water quality which provides for the 
protection and propagation of fish, shellfish, and wildlife and 
provides for recreation in and on the water.'' 33 U.S.C. 1251(a)(2). 
Therefore, the agencies disagree that consideration of biological 
effects on paragraph (a)(1) waters is inconsistent with the Clean Water 
Act.
    Finally, several commenters asserted that the Clean Water Act 
requires broader protections than those afforded by the significant 
nexus standard and relatively permanent standard. The agencies agree 
that the Clean Water Act requires broader protection than the 
relatively permanent standard, but have concluded, as explained in 
section IV.A.3 of this preamble, that the significant nexus standard is 
the best construction of the scope of the Clean Water Act.
c. Comments Regarding Categories of Waters in This Rule
    Multiple commenters expressed concern that the proposed rule would 
exceed the agencies' statutory authority by providing for jurisdiction 
over broad categories of waters (for example, tributaries) that the 
commenters asserted are not within the limits of the Clean Water Act 
pursuant to Rapanos. The agencies disagree. As explained above, this 
rule reflects the agencies' independent judgment on the scope of 
``waters of the United States'' based on the text of the relevant 
provisions of the Clean Water Act and the statute as a whole, the 
objective and history of the Clean Water Act, the scientific record, 
the agencies' experience and technical expertise, and other relevant 
Supreme Court cases. This rule reflects carefully tailored 
modifications to the 1986 regulations to incorporate both the 
relatively permanent standard and the significant nexus standard such 
that the waters covered by the definition are within the limits of the 
Clean Water Act.
    Many commenters discussed the agencies' legal authority to assert 
jurisdiction over tributaries, including specific types of tributaries 
(e.g., ephemeral, intermittent, and perennial). Some commenters 
asserted that providing for jurisdiction over ephemeral and 
intermittent streams in the definition of ``waters of the United 
States'' is not supported by Rapanos. In this rule, the agencies are 
neither categorically including nor categorically excluding ephemeral 
and intermittent tributaries. Nor are the agencies codifying the 
opinions in Rapanos. Rather, the agencies are interpreting the phrase 
``waters of the United States'' to include tributaries that meet either 
the significant nexus standard or the relatively permanent standard 
based on their conclusions in section IV.A of this preamble. Further, 
there is nothing in the text of the statute or its legislative history 
that excludes some categories of

[[Page 3053]]

tributaries based on their flow regime. Indeed, as discussed further 
below, the best available science demonstrates that ephemeral and 
intermittent streams can significantly affect the chemical, physical, 
and biological integrity of paragraph (a)(1) waters--i.e., traditional 
navigable waters, the territorial seas, and interstate waters.
    Multiple commenters suggested that, pursuant to Supreme Court 
precedent and the Clean Water Act, jurisdiction over non-navigable 
tributaries should be limited to tributaries (1) containing clearly 
discernible features and contributing consistent flow into traditional 
navigable waters; or (2) that carry a volume of water needed for 
navigable capacity of a traditional navigable water; or (3) of a 
quality needed for interstate commerce, where impairment of water 
quality would have a negative effect on interstate commerce. The 
agencies disagree that the case law, the statute, or the Constitution 
provide these precise limitations on the scope of tributaries covered 
by the Clean Water Act. The text of ``navigable waters,'' and of its 
specialized definition, does not include particular flow requirements. 
As discussed further below, the agencies have concluded that 
tributaries that meet either the relatively permanent standard or the 
significant nexus standard are ``waters of the United States,'' and 
flow is a consideration under both standards. These limitations are 
informed by Supreme Court case law and designed to be well within 
constitutional limits.
    In contrast, other commenters asserted that tributaries should be 
categorically jurisdictional rather than subject to a case-specific 
analysis and that the Rapanos decision supports a categorical approach. 
The agencies agree that Justice Kennedy's concurring opinion in Rapanos 
did not reject the agencies' then-existing regulations governing 
tributaries, which were more categorical than this rule. 547 U.S. at 
781; see also id. at 761. More broadly, it is a well-established 
principle of administrative law that agencies may choose to proceed via 
rulemaking or adjudication. NLRB v. Bell Aerospace Co. Div. of Textron, 
Inc., 416 U.S. 267, 294 (1974) (``[T]he choice between rulemaking and 
adjudication lies in the first instance within the [agency's] 
discretion.''). With respect to the significant nexus standard in 
particular, Justice Kennedy stated that the agencies could proceed to 
determine tributaries and their adjacent wetlands jurisdictional 
through regulations or adjudication. See Rapanos, 547 U.S. at 780-81. 
As explained in section IV.A.3.a.iii of this preamble, the agencies 
have concluded that adjudication of which tributaries are within Clean 
Water Act protections, through case-specific application of the 
significant nexus standard or the relatively permanent standard under 
this rule, is appropriate. See section IV.C.10 of this preamble for 
additional guidance to landowners on determinations of jurisdiction and 
the appeals process for such determinations.
    Many commenters also discussed the agencies' legal authority to 
assert jurisdiction over adjacent wetlands. Some commenters stated that 
the proposed rule's relatively permanent standard was inconsistent with 
the Rapanos plurality opinion, asserting that the plurality opinion 
requires a continuous surface connection for adjacent wetlands to be 
jurisdictional. As stated elsewhere, the agencies disagree that the 
relatively permanent standard as applied in this rule is inconsistent 
with the plurality opinion. Under this rule, an adjacent wetland is 
jurisdictional if there is a continuous surface connection between that 
adjacent wetland and a paragraph (a)(2) impoundment or jurisdictional 
tributary when the paragraph (a)(2) impoundment or jurisdictional 
tributary is relatively permanent.
    In addition, some commenters expressed concern that the proposed 
rule's aggregation of wetlands and the relevant reach approach would be 
contrary to Justice Kennedy's significant nexus standard, which the 
commenters suggested requires that each wetland be judged in its own 
right. The agencies disagree that aggregation of wetlands and their 
tributaries is inconsistent with the significant nexus standard. First, 
Justice Kennedy explicitly stated that similarly situated waters should 
be assessed for a significant nexus ``alone or in combination.'' 
Rapanos, 547 U.S. at 780. Justice Kennedy understood that waters 
provide critical functions to downstream waters in combination, 
explaining: ``With respect to wetlands, the rationale for Clean Water 
Act regulation is, as the Corps has recognized, that wetlands can 
perform critical functions related to the integrity of other waters--
functions such as pollutant trapping, flood control, and runoff 
storage. Accordingly, wetlands possess the requisite nexus, and thus 
come within the statutory phrase `navigable waters,' if the wetlands, 
either alone or in combination with similarly situated lands in the 
region, significantly affect the chemical, physical, and biological 
integrity of other covered waters more readily understood as 
`navigable.' '' Id. at 779-780 (citing 33 CFR 320.4(b)(2)). And Justice 
Kennedy's understanding is scientifically correct--though filling in a 
single wetland might not on its own materially influence a paragraph 
(a)(1) water, its impact is more likely to be significant when 
evaluated in combination with other similarly situated waters. Second, 
the agencies interpret ``waters of the United States'' to include 
waters that meet the significant nexus standard as codified in this 
rule because the agencies have determined, informed by the best 
available science and the text, structure, and legislative history of 
the Clean Water Act, that this standard, including the aggregation of 
waters authorized by it, advances the objective of the Act. The 
agencies have also established a definition of ``significantly affect'' 
in this rule that identifies the factors and the functions for 
determining whether the significant nexus standard is met, thus 
ensuring that the agencies' determinations of jurisdiction are based on 
consistent application of sound scientific principles.
    Further, several commenters stated that the agencies should assert 
jurisdiction only over those wetlands that directly abut other ``waters 
of the United States.'' These commenters asserted that doing otherwise 
would exceed the constitutional limits of the agencies' Clean Water Act 
jurisdiction. For the reasons discussed above, the agencies disagree 
that only wetlands that directly abut other ``waters of the United 
States'' should be jurisdictional. Moreover, as discussed elsewhere in 
this preamble, the addition of the significant nexus standard in this 
rule ensures that the definition of ``waters of the United States'' 
does not exceed constitutional limits.
    In contrast, several commenters asserted that all adjacent 
wetlands--not just those adjacent to the paragraph (a)(1) waters--
should be categorically jurisdictional. Some of these commenters 
suggested that providing categorical protection for such wetlands is 
necessary to achieve the Clean Water Act's statutory objective. The 
agencies agree that providing categorical protection of adjacent 
wetlands can be a means of achieving the Act's objective but disagree 
that it is the only means. As noted by Justice Kennedy, the agencies 
can reasonably proceed to determine which tributaries and their 
adjacent wetlands are jurisdictional through regulations or 
adjudication, see 547 U.S. at 780-81; see also NLRB v. Bell Aerospace 
Co. Div. of Textron, Inc., 416 U.S. at 294. With respect to wetlands 
adjacent to tributaries, the agencies are requiring case-specific 
determinations

[[Page 3054]]

of whether such wetlands meet the relatively permanent standard or the 
significant nexus standard to be jurisdictional under this rule.
    Many commenters also addressed the agencies' legal authority to 
assert jurisdiction over paragraph (a)(5) waters (the category of 
waters described in paragraph (a)(3) of the proposed rule). Some 
commenters suggested that, per the Supreme Court's decision in SWANCC, 
the agencies lack authority to assert jurisdiction over paragraph 
(a)(5) waters or that, under Rapanos, the significant nexus standard 
should be applied only to tributaries or wetlands adjacent to 
tributaries, not to paragraph (a)(5) waters. First, as explained 
further in section IV.A.1 of this preamble, in this rule the agencies 
are exercising the authority granted to them by Congress to construe 
and implement the Clean Water Act and to interpret an ambiguous term 
and its statutory definition. Therefore, while the agencies' 
interpretation of the statute is informed by Supreme Court decisions, 
including Rapanos, it is not an interpretation of SWANCC or the 
multiple opinions in Rapanos, nor is it based on an application of the 
Supreme Court's principles as set forth in Marks to derive a governing 
rule of law from a decision of the Court in a case such as Rapanos 
where no opinion commands a majority. Furthermore, the agencies 
disagree that asserting jurisdiction over any waters that meet the 
significant nexus standard, including any paragraph (a)(5) waters, is 
inconsistent with SWANCC or Rapanos. Based on the law, the science, and 
agency expertise, the agencies conclude that the significant nexus 
standard applies to tributaries, adjacent wetlands, and intrastate 
lakes and ponds, streams, or wetlands not covered by other categories 
(i.e., paragraphs (a)(3), (a)(4), and (a)(5) waters under this rule). 
Justice Kennedy's explication of the significant nexus standard applies 
to each of these types of waters. In Rapanos, Justice Kennedy reasoned 
that Riverside Bayview and SWANCC ``establish the framework for'' 
determining whether an assertion of regulatory jurisdiction constitutes 
a reasonable interpretation of ``navigable waters''--``the connection 
between a nonnavigable water or wetland and a navigable water may be so 
close, or potentially so close, that the Corps may deem the water or 
wetland a `navigable water' under the Act;'' and ``[a]bsent a 
significant nexus, jurisdiction under the Act is lacking.'' 547 U.S. at 
767. Justice Kennedy further explained that ``[t]he required nexus must 
be assessed in terms of the statute's goals and purposes. Congress 
enacted the law to `restore and maintain the chemical, physical, and 
biological integrity of the Nation's waters,' and it pursued that 
objective by restricting dumping and filling in `navigable waters'.'' 
Id. at 779 (citing 33 U.S.C. 1251(a), 1311(a), 1362(12)). Justice 
Kennedy then concluded that the term ``waters of the United States'' 
encompasses wetlands and other waters that ``possess a `significant 
nexus' to waters that are or were navigable in fact or that could 
reasonably be so made.'' Id. at 759 (citation omitted). While Justice 
Kennedy's discussion of the application of the significant nexus 
standard focused on adjacent wetlands in light of the facts of the 
cases before him, his opinion is clear that he does not conclude that 
the significant nexus analysis applies only to adjacent wetlands. As he 
explicitly states, ``the connection between a nonnavigable water or 
wetland and a navigable water may be so close, or potentially so close, 
that the Corps may deem the water or wetland a `navigable water' under 
the Act.'' Id. at 767 (emphasis added). Fundamentally, Justice 
Kennedy's significant nexus analysis is about the fact, long 
acknowledged by Supreme Court case law, that protection of waters from 
pollution can be achieved only by controlling pollution of upstream 
waters. In addition, the Court in SWANCC did not hold that ``other 
waters'' (a category that has been modified and codified in this rule 
as paragraph (a)(5) waters) could never be jurisdictional; rather it 
held that the potential use of isolated ponds as habitat for migratory 
birds could not be used as the sole basis to justify treating those 
ponds as ``waters of the United States.'' See 531 U.S. at 164-65, 171-
72. Indeed, the SWANCC Court in describing Riverside Bayview stated 
that ``it was the significant nexus between the wetlands and `navigable 
waters' that informed our reading of the CWA'' in that case. Id. at 
167. In this rule, the agencies are not protecting paragraph (a)(5) 
waters based on their potential use as habitat for migratory birds or 
based on their use broadly in interstate commerce as the 1986 
regulations did. Instead, this rule includes paragraph (a)(5) waters on 
a case-specific basis based on their importance to the integrity of 
traditional navigable waters, the territorial seas, and interstate 
waters because they meet either the relatively permanent standard or 
the significant nexus standard.
    Other commenters stated that the proposed rule does not go far 
enough in protecting paragraph (a)(5) waters. The agencies have 
concluded that this rule's reliance on the relatively permanent 
standard and significant nexus standard properly balances the Clean 
Water Act's broad statutory objective, while giving meaning to the word 
``navigable.'' Accordingly, the agencies are not asserting jurisdiction 
over waters and wetlands simply where ``the use, degradation or 
destruction of [such waters] could affect interstate or foreign 
commerce.'' Cf. 33 CFR 328.3(a)(3) (1999).

B. Alternatives to This Rule

    In promulgating a rule to repeal existing regulations, agencies 
must address and consider alternative ways of achieving the relevant 
statute's objectives and must provide adequate reasons to abandon those 
alternatives. Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. 
Co., 463 U.S. 29, 48 (1983); see also FCC v. Fox Television Stations, 
Inc., 556 U.S. 502, 515 (2009). As discussed below, the agencies have 
thoroughly considered alternatives to this rule and have concluded that 
this final rule best accomplishes the agencies' goals to promulgate a 
rule that advances the objective of the Clean Water Act, is consistent 
with Supreme Court decisions, is informed by the best available 
science, and promptly and durably restores vital protections to the 
nation's waters. The agencies have reconsidered the policies, 
interpretations, and conclusions of the 2020 NWPR. Although the 2020 
NWPR has been vacated, it is the text currently in the Code of Federal 
Regulations. For the reasons articulated in this preamble, the agencies 
are changing their approach from that of the 2020 NWPR to interpreting 
the scope of ``waters of the United States.''
1. 2015 Clean Water Rule
    The agencies are not repromulgating the 2015 Clean Water Rule. 
Unlike aspects of the 2015 Clean Water Rule, this rule is not based on 
categorical significant nexus determinations. Rather, this rule 
generally restores the longstanding and familiar categories of the 1986 
regulations and establishes jurisdictional limitations based on case-
specific application of the relatively permanent standard and the 
significant nexus standard to certain categories of waters in the rule.
    Many commenters expressed support for the 2015 Clean Water Rule 
because they viewed it as informed by science, and because under that 
rule certain types of waters were categorically jurisdictional, which 
eliminated the need for extensive case-by-case

[[Page 3055]]

jurisdictional determinations. Many other commenters asserted that they 
did not support the 2015 Clean Water Rule because they viewed that rule 
as expanding Federal jurisdiction over waters that should not be 
jurisdictional. The agencies have concluded that the 2015 Clean Water 
Rule, while designed to advance the objective of the Clean Water Act, 
is not the best alternative to meet the policy goals of the agencies: 
to quickly promulgate a durable rule that retains the protections of 
the longstanding regulatory framework and avoids harms to important 
aquatic resources, informed by the best available science and 
consistent with the agencies' determination of the statutory limits on 
the scope of the ``waters of the United States,'' informed by relevant 
Supreme Court case law. Moreover, agencies may choose to proceed via 
rulemaking or adjudication. NLRB v. Bell Aerospace Co., 416 U.S. 267, 
294 (1974) (``[T]he choice between rulemaking and adjudication lies in 
the first instance within the [agency's] discretion.''). With respect 
to the significant nexus standard in particular, Justice Kennedy also 
stated that the agencies could proceed to determine tributaries and 
their adjacent wetlands jurisdictional through regulations or 
adjudication. See 547 U.S. at 780-81. As explained in section 
IV.A.3.a.iii of this preamble, the agencies have concluded that the 
approach in this rule--i.e., providing categorical jurisdiction for 
paragraph (a)(1) waters and for wetlands adjacent to paragraph (a)(1) 
waters, and adjudicating which waters in paragraphs (a)(2) through (5) 
are ``waters of the United States'' through case-specific application 
of the significant nexus standard or the relatively permanent standard 
under this rule--is appropriate and fulfills the goals of the agencies 
and the objective of the Clean Water Act.
2. 2019 Repeal Rule
    The agencies agree with the concept in the 2019 Repeal Rule of 
returning to the pre-2015 regulatory framework as a means of restoring 
a longstanding and familiar regulatory regime,\67\ but find that this 
rule is preferable to the 2019 Repeal Rule for several reasons. As an 
initial matter, like the 2019 Repeal Rule, this rule seeks to return 
generally to the longstanding regulatory framework that existed prior 
to the 2015 Clean Water Rule, but this rule also restores those 
regulations with necessary limitations to ensure the definition of 
``waters of the United States'' reflects consideration of the agencies' 
statutory authority under the Clean Water Act and relevant Supreme 
Court decisions. Additionally, compared to the 2019 Repeal Rule, this 
rule provides greater clarity by adding a new definition of 
``significantly affect'' and by streamlining and restructuring the 1986 
regulations, including by consolidating certain provisions. This rule 
also codifies a number of exclusions for features that were generally 
considered non-jurisdictional under the pre-2015 regulatory regime and 
thus provides more clarity and certainty than the 2019 Repeal Rule.
---------------------------------------------------------------------------

    \67\ 2019 Repeal Rule, Response to Comments at 9 (``The agencies 
find that reinstating the longstanding and familiar pre-2015 Rule 
regulatory regime will provide regulatory certainty in this interim 
period . . . .''), 15 (``[T]his final rule to recodify the 1986 
regulations will provide greater regulatory certainty and nationwide 
consistency while the agencies consider public comments on the 
proposed revised definition of ``waters of the United States.'').
---------------------------------------------------------------------------

    Moreover, the agencies have substantial concerns regarding the 
legal rationale underpinning the 2019 Repeal Rule. In particular, the 
agencies are concerned that the interpretation of relevant Supreme 
Court case law in the 2019 Repeal Rule is flawed and thereby led to an 
erroneous assessment of the legality of the approach to the significant 
nexus standard in the 2015 Clean Water Rule. See, e.g., 84 FR 56638-52 
(October 22, 2019). The agencies' reading of the Clean Water Act in the 
2019 Repeal Rule is also inconsistent with the agencies' considered 
interpretation, at this time, of the Act. For these reasons, the 
agencies find that the 2019 Repeal Rule is not an appropriate 
alternative to this rule.
3. 2020 NWPR
    The agencies have also evaluated the 2020 NWPR as an alternative to 
this rule. After carefully considering the 2020 NWPR in light of the 
text, objective, and legislative history of the Clean Water Act, 
Supreme Court case law, the best available scientific information, and 
the agencies' experience in implementing it for over a year, the 
agencies do not find that the 2020 NWPR is a suitable alternative to 
this rule.
a. The 2020 NWPR Failed To Advance the Objective of the Clean Water Act
    The agencies do not consider the 2020 NWPR to have advanced the 
statutory objective of the Clean Water Act, which the Supreme Court 
recently emphasized is an important aspect of defining the 
jurisdictional scope of the Act. See, e.g., Maui, 140 S. Ct. at 1468-69 
(emphasizing the importance of considering the Clean Water Act's 
objective when determining the scope of the Act and finding that 
``[t]he Act's provisions use specific definitional language to achieve 
this result,'' including the phrase ``navigable waters''). One critical 
example of the 2020 NWPR's failure to advance the Clean Water Act's 
objective is its removal of the significant nexus standard without 
considering an alternative approach to protecting waters that 
significantly affect paragraph (a)(1) waters. To be clear, while the 
agencies view the significant nexus standard as the best interpretation 
of section 502(7) of the Clean Water Act, the agencies do not view the 
Supreme Court's interpretations of the scope of ``waters of the United 
States'' as requiring adoption of that approach. Rapanos, 547 U.S. at 
758 (Roberts, C.J., concurring). Yet the 2020 NWPR's rejection of the 
significant nexus standard while failing to adopt any alternative 
standard for jurisdiction that adequately addresses the effects of 
degradation of upstream waters on paragraph (a)(1) waters, fails to 
advance the Clean Water Act's objective.
    The significant nexus inquiry reflects and furthers the objective 
of the Clean Water Act by allowing for a scientific evaluation of the 
effect of wetlands, tributaries, and other types of waters on paragraph 
(a)(1) waters. For that reason, evolving forms of this inquiry are 
present in Riverside Bayview, SWANCC, and Justice Kennedy's concurring 
opinion in Rapanos. The 2020 NWPR rejected this scientific approach and 
instead, for example, categorically excluded ephemeral features without 
appropriately considering scientific information about their important 
effects on the integrity of paragraph (a)(1) waters. In addition, in 
limiting the scope of protected wetlands to those that touch other 
jurisdictional waters or demonstrate evidence (which could include a 
natural berm, bank, dune, or similar natural feature) of a regular 
surface water connection to other jurisdictional waters, the 2020 NWPR 
failed to appropriately consider the many effects of other categories 
of wetlands on paragraph (a)(1) waters. For example, ephemeral streams 
that flow directly into the Rio Grande (a traditional navigable water) 
and wetlands separated from the Mississippi River (a traditional 
navigable water) by artificial levees and that lack a direct hydrologic 
surface connection to the river in a typical year, would be non-
jurisdictional under the 2020 NWPR, yet both can have significant 
effects on these traditional navigable waters.
    The 2020 NWPR contended that the drastic reduction in the scope of 
Clean Water Act jurisdiction ``pursues'' the objective of the Act 
because it would be

[[Page 3056]]

supplemented by the Act's non-regulatory programs as well as Tribal, 
State, and local efforts. The 2020 NWPR explained: ``The CWA's 
longstanding regulatory permitting programs, coupled with the controls 
that States, Tribes, and local entities choose to exercise over their 
land and water resources, will continue to address the discharge of 
pollutants into waters of the United States, and the CWA's non-
regulatory measures will continue to address pollution of the nation's 
waters generally. These programs and measures collectively pursue the 
objective of restoring and maintaining the chemical, physical, and 
biological integrity of the nation's waters.'' 85 FR 22269 (April 21, 
2020). The agencies disagree with the 2020 NWPR's assertion that such 
``collective pursuit'' of the objective of the Clean Water Act based on 
these programs and measures appropriately considers the objective of 
the Act and have concluded that the 2020 NWPR did not advance the 
objective of the Act, the proper measure under the statute and Supreme 
Court case law of a rule defining ``waters of the United States.''
    The agencies agree with the 2020 NWPR's position that the Clean 
Water Act's non-regulatory measures, such as grantmaking and technical 
assistance authorities, advance the objective the Act. However, the 
agencies do not view these authorities as limiting the scope of 
``waters of the United States,'' or as relevant to determining whether 
a definition of ``waters of the United States'' advances the objective 
of the Clean Water Act. The non-regulatory Clean Water Act programs 
cited by the 2020 NWPR complement and support the permitting programs 
at the core of the Act, rather than limiting their geographic scope. 
For example, the 2020 NWPR cited the Clean Water Act's provisions to 
address pollution into key waters in its discussion, including the 
Great Lakes, 33 U.S.C. 1258, the Chesapeake Bay, see id. at 1267(a)(3), 
Long Island Sound, see id. at 1269(c)(2)(D), and Lake Champlain, see 
id. at 1270(g)(2). These resources are ``waters of the United States'' 
to which regulatory programs apply, and the technical assistance and 
grants in the cited sections assist States and others in achieving the 
requirements of the Clean Water Act, but they do not limit the 
regulatory programs' scope. To the extent there is ambiguity as to the 
effects of these non-regulatory programs on the scope of the ``waters 
of the United States,'' the agencies have concluded based on the text 
and structure of the statute that they are complementary, rather than 
limiting.
    As discussed in section III.A of this preamble, the Clean Water 
Act's fundamental innovation in 1972 was to ``establish an all-
encompassing program of water pollution regulation,'' Int'l Paper Co. 
v. Ouellette, 479 U.S. 481, 492-93 (1987). The definition of ``waters 
of the United States'' establishes the scope of that program. The 
agencies therefore find that it is appropriate to consider whether the 
definition of the scope of waters to which the Clean Water Act's water 
pollution regulations apply helps to achieve that objective. Thus, the 
2020 NWPR's statement that this rule ``pursues'' the objective of the 
Act if Clean Water Act and non-Clean Water Act programs are viewed in 
``combination'' is not consistent with the better reading of the text 
and structure of the Act, its legislative history, or Supreme Court 
decisions concerning the effect of enactment of the Clean Water Act in 
1972, nor does it fulfill the agencies' obligation to consider the 
objective of the Clean Water Act by assessing the water quality effects 
of revising the definition of ``waters of the United States.''
    The preamble to the 2020 NWPR also cited the introductory policy 
provision of the Clean Water Act in section 101(b), to protect the 
``primary responsibilities and rights of States to prevent, reduce, and 
eliminate pollution'' as a justification, in part, for its line-
drawing. For example, one of the most environmentally significant 
decisions in the 2020 NWPR was its categorical exclusion of all 
ephemeral features from Clean Water Act jurisdiction. The agencies 
cited section 101(b) as a basis for this exclusion, because the 
exclusion would ``respect[] State and Tribal land use authority over 
features that are only episodically wet during and/or following 
precipitation events.'' 85 FR 22319. Nothing in the agencies' 
explanation, however, links the agencies' line-drawing to the text or 
purpose of section 101(b). Nor do the agencies, at this time, see any 
linkage between the flow regime of ephemeral features and the nature or 
extent of State authorities referenced in section 101(b). Indeed, as 
discussed in section IV.A.c.i of this preamble, available science 
unequivocally demonstrates that ephemeral features can implicate the 
important Federal interest in the protection of the integrity of 
traditional navigable waters, the territorial seas, and interstate 
waters. Likewise, the 2020 NWPR cited section 101(a) as support for 
categorically excluding ephemeral features, but again did not explain 
how this decision relates to or advances the Clean Water Act's 
objective. 85 FR 22277 (April 21, 2020).
    The 2020 NWPR similarly relied upon the policy provision in section 
101(b) as a basis for its definition of adjacent wetlands, in 
particular the decision to exclude from consideration subsurface 
hydrologic connections between a wetland and an adjacent water when 
determining jurisdiction. It stated, ``balancing the policy in CWA 
section 101(a) with the limitations on Federal authority embodied in 
CWA section 101(b), the agencies are finalizing the definition of 
`adjacent wetlands' that does not include subsurface hydrologic 
connectivity as a basis for determining adjacency.'' Id. at 22313. 
Again, the 2020 NWPR did not explain how excluding consideration of 
subsurface hydrologic connections relates to or derives from the text 
of section 101(b), and the agencies do not now discern such a linkage. 
And as with the definition of ``tributaries,'' the 2020 NWPR did not 
explain how this choice relates to or advances the objective of the 
Clean Water Act.
    In sum, based on the text and structure of the statute and Supreme 
Court case law, the agencies have determined that the 2020 NWPR is not 
a suitable alternative to this rule because it fails to advance the 
objective of the Clean Water Act. The 2020 NWPR does not establish 
either the significant nexus standard or an alternative standard that 
similarly advances the objective of the Clean Water Act by protecting 
waters, including ephemeral features, wetlands, and paragraph (a)(5) 
waters where they have a significant effect on the chemical, physical, 
or biological integrity of traditional navigable waters, the 
territorial seas, and interstate waters. Nor does the 2020 NWPR 
appropriately value the importance of Federal programs in achieving the 
objective of the Clean Water Act.
b. The 2020 NWPR Was Inconsistent With the Best Available Scientific 
Information
    The 2020 NWPR's exclusion of major categories of waters from the 
protections of the Clean Water Act, specifically in the definitions of 
``tributary'' and ``adjacent wetlands,'' runs counter to the scientific 
record demonstrating how such waters can affect the integrity of 
downstream waters. Specifically, as many commenters on the proposed 
rule noted, its categorical exclusion of ephemeral features and large 
categories of wetlands was inconsistent with the scientific record 
before the agencies. In addition, the 2020 NWPR's limits on the scope 
of protected wetlands to those

[[Page 3057]]

that touch or demonstrate evidence of a regular surface water 
connection to other jurisdictional waters run counter to the ample 
scientific information demonstrating the effects of wetlands on 
downstream waters, including paragraph (a)(1) waters, when they have 
other types of connections.
    First, the definition of the term ``tributary'' in the 2020 NWPR 
categorically excluded ephemeral features from the regulatory 
protections of the Clean Water Act, contrary to scientific information 
conclusively demonstrating the vital role these streams can play in 
protecting the integrity of downstream waters, including paragraph 
(a)(1) waters. The science is clear that aggregate effects of ephemeral 
streams ``can have substantial consequences on the integrity of the 
downstream waters'' and that the evidence of such downstream effects is 
``strong and compelling,'' as discussed above. Science Report at 6-10, 
6-13. EPA's SAB Review of the draft Science Report explains that 
ephemeral streams ``are no less important to the integrity of the 
downgradient waters'' than perennial or intermittent streams. 2014 SAB 
Review at 22-23, 54 fig. 3. While in the arid Southwest, streams flow 
into downstream waters less frequently than they do in the wetter East, 
the Science Report emphasizes that short duration flows through 
ephemeral streams can transport large volumes of water to downstream 
rivers. Science Report at 6-9. For instance, the report notes that 
ephemeral streams supplied 76% of flow to the Rio Grande following a 
large rainstorm. Id. at 3-8. The 2014 SAB Review emphasizes that the 
``cumulative effects'' of ephemeral flows in arid landscapes can be 
``critical to the maintenance of the chemical, physical, and biological 
integrity'' of downstream waters. 2014 SAB Review at 22.
    Similarly, the 2020 NWPR's definition of ``adjacent wetlands'' 
excluded many categories of wetlands that can play a vital role in 
protecting the integrity of waters to which they are connected, 
including paragraph (a)(1) waters. In defining ``adjacent wetlands,'' 
the 2020 NWPR limited the scope of wetlands protected by the Clean 
Water Act's regulatory programs to those that either abut or have 
evidence of certain surface water connections to other protected waters 
in a typical year. 85 FR 22340. Specifically, the rule encompassed 
wetlands that (i) abut, meaning to touch, another jurisdictional water; 
(ii) are flooded by a jurisdictional water in a typical year; (iii) are 
separated from a jurisdictional water only by a natural feature, such 
as a berm, which provides evidence of a direct hydrologic surface 
connection with that water; or (iv) are separated from a jurisdictional 
water only by an artificial structure so long as that structure allows 
for a direct hydrologic surface connection between the wetlands and the 
water in a typical year. Id. As with the tributary definition, the 2020 
NWPR stated that the definition of ``adjacent wetlands'' is ``informed 
by science.'' Id. at 22314. Yet the 2020 NWPR's limits on the scope of 
protected wetlands to those that touch or demonstrate evidence of a 
regular surface water connection to other jurisdictional waters 
contradicted the ample scientific information before the agencies 
conclusively demonstrating the effects of wetlands on downstream waters 
when they have other types of surface connections, such as wetlands 
that overflow and flood jurisdictional waters or wetlands with less 
frequent surface water connections; wetlands with shallow subsurface 
connections to other protected waters; or other wetlands proximate to 
jurisdictional waters. See Rapanos, 547 U.S. at 786 (Kennedy, J., 
concurring in the judgment) (``Given the role wetlands play in 
pollutant filtering, flood control, and runoff storage, it may well be 
the absence of a hydrologic connection (in the sense of interchange of 
waters) that shows the wetlands' significance for the aquatic 
system.''). As commenters noted, under the 2020 NWPR's approach, if a 
river were surrounded by hundreds of acres of wetland, building a road 
or levee between a river and a wetland complex could potentially sever 
Clean Water Act protections for the entire wetland complex.
    The overwhelming scientific information before the agencies weighs 
decisively against the limited definition of ``adjacent wetlands'' in 
the 2020 NWPR. Available scientific information demonstrates the 
significant effects of categories of wetlands excluded by the 2020 NWPR 
on the chemical, physical, and biological integrity of paragraph (a)(1) 
waters. For example, whereas the 2020 NWPR provided that wetlands 
flooded by jurisdictional waters are only protected if the flooding 
occurs in a ``typical year,'' the Science Report states that wetlands 
that are ``rarely'' or ``infrequently'' flooded by streams and rivers 
can be ``highly connected'' to those waters and have ``long-lasting 
effects'' on them. Science Report at 4-39. The Science Report notes 
that effects ``critical to maintaining the health of the river'' result 
from large floods that provide ``infrequent connections'' with more 
distant wetlands. Id. Reflecting these concerns, the October 16, 2019 
SAB Draft Commentary on the proposed 2020 NWPR states that the narrow 
definition of ``adjacent wetlands'' in the 2020 NWPR as it was proposed 
``departs from established science.'' The agencies have weighed these 
statements and in light of the information about the importance of 
``infrequently'' flooded wetlands to downstream waters, have concluded 
that excluding wetlands that lack the limited types of surface water 
connections to other jurisdictional waters required by the 2020 NWPR 
lacks scientific support.
    The SAB's assessment of the 2020 NWPR proposal recognizes that the 
proposal was not consistent with the scientific information in the 
record, including the Draft Science Report that the SAB had previously 
reviewed. SAB Commentary on the Proposed Rule Defining the Scope of 
Waters Federally Regulated Under the Clean Water Act (February 27, 
2020) (hereinafter, ``SAB Commentary''). The SAB Commentary emphasizes 
that the proposal does not ``fully incorporate the body of science on 
connectivity'' that the SAB had reviewed in the Draft Science Report 
and offers ``no scientific justification for disregarding the 
connectivity of waters accepted by current hydrological science.'' Id. 
at 2.
    The 2020 NWPR stated that the ``agencies' decisions in support of 
this rule have been informed by science.'' 85 FR 22288 (April 21, 
2020). For example, the 2020 NWPR cited the concept of a ``connectivity 
gradient'' as a basis for excluding ephemeral features. Id. (citing the 
SAB Commentary). The 2020 NWPR referred to the SAB Commentary's 
recommendation that the agencies recognize that connectivity occurs 
along a gradient allowing for variation in chemical, physical, and 
biological connections. Id. (citing the SAB Commentary at 3). The 2020 
NWPR asserted that there is a ``decreased'' likelihood that waters with 
``less than perennial or intermittent'' flow, i.e., ephemeral streams, 
will affect the chemical, physical, and biological integrity of 
downstream waters. 85 FR 22288 (April 21, 2020).
    Upon careful review, the agencies have concluded that the 2020 
NWPR's reliance on the SAB's recommendation is out of context and is 
inconsistent with the information in the SAB Commentary as a whole. The 
connectivity gradient the 2020 NWPR cited was just a hypothetical 
example \68\

[[Page 3058]]

meant to illustrate a single aspect of connectivity--hydrological, or 
physical connectivity--and sheds no light on the many other ways that 
features connect to and affect downstream waters. According to the SAB 
itself, the scientific information the agencies provided in support of 
categorically excluding ephemeral features does not fully represent the 
discussion in the cited SAB Commentary and runs counter to key elements 
of the scientific record before the agencies. SAB Commentary at 2.
---------------------------------------------------------------------------

    \68\ The figure cited is captioned in part as ``Hypothetical 
illustration of connectivity gradient and potential consequences to 
downstream waters.'' 2014 SAB Review at 54 (emphasis added). Nowhere 
in its review does the 2014 SAB Review indicate that this is the 
actual or only connectivity gradient.
---------------------------------------------------------------------------

    The 2020 NWPR also stated that the line it drew between regulated 
and non-regulated wetlands, which excluded large categories of wetlands 
covered by previous regulatory regimes is ``informed by science.'' 85 
FR 22314 (April 21, 2020). The 2020 NWPR cited statements from the 2014 
SAB Review to the effect that wetlands situated alongside other waters 
are likely to be connected to those waters, whereas ``those connections 
become less obvious'' as the distance ``increases.'' Id. (citing the 
2014 SAB Review at 55); see also id. at 22314 (citing the 2014 SAB 
Review at 60 (stating ``[s]patial proximity is one important 
determinant [influencing the connections] between wetlands and 
downstream waters'')). In addition, the 2020 NWPR cited a statement in 
the Science Report that explained, ``areas that are closer to rivers 
and streams have a higher probability of being connected than areas 
farther away.'' Id. at 22314 (citing the Science Report at ES-4).
    Despite these citations, the 2020 NWPR's definition of ``adjacent 
wetlands'' was not based on proximity, but instead on a ``direct 
hydrologic surface connection,'' a factor that is distinct from 
proximity. See id. at 22340. The 2020 NWPR's definition of ``adjacent 
wetlands'' may exclude wetlands fifteen feet away from jurisdictional 
waters if they are separated by a levee that does not convey flow in a 
typical year, but include wetlands much further away so long as they 
are inundated by flooding from the jurisdictional water in a typical 
year. Therefore, neither of the two scientific rationales the 2020 NWPR 
cited for its conclusions actually support the lines drawn in that 
rule.
    Many commenters agreed with the agencies that the 2020 NWPR was 
inconsistent with the best available science. Some commenters asserted, 
however, that the definition of ``waters of the United States'' is a 
policy interpretation that may be informed by science but cannot be 
based on science alone. As discussed in section IV.A.2 of this 
preamble, the agencies agree that science alone cannot dictate where to 
draw the line defining ``waters of the United States.'' But science is 
critical to determining how to attain Congress's plainly stated 
objective to restore and maintain the chemical, physical, and 
biological integrity of the nation's waters and properly evaluating 
which waters are the subject of Federal jurisdiction due to their 
effects on paragraph (a)(1) waters. Only by relying upon scientific 
principles to understand the way waters affect one another can the 
agencies know whether they are achieving that objective. The 2020 NWPR 
is not a suitable alternative to this rule because it cannot advance 
the objective of the Act given its lack of scientific support.
c. The 2020 NWPR Was Difficult To Implement and Yielded Inconsistent 
Results
    In addition to the above concerns, the agencies' experience 
implementing the 2020 NWPR for over a year made clear that foundational 
concepts underlying much of the 2020 NWPR were confusing and difficult 
to implement. While any rule that draws lines between jurisdictional 
waters and non-jurisdictional waters will involve some implementation 
challenges, the agencies have found the challenges imposed by the 2020 
NWPR to be impracticable in important respects.
    Many commenters stated that the agencies should retain the 2020 
NWPR because it was clear, pragmatic, and easy to implement. For 
example, commenters stated that the rule provided ``bright lines,'' was 
based on readily observable surface features, and categorically 
excluded certain categories of waters. The agencies recognize that the 
regulatory text of the 2020 NWPR contained categorical language and 
referred to observable surface features. However, the ``bright lines'' 
and surface feature tests relied upon the concept of ``typical year,'' 
which, as other commenters pointed out, and as discussed further below, 
was extremely challenging to implement and led to arbitrary results. As 
a commenter emphasized, contrary to statements often made about the 
2020 NWPR, under that rule landowners could not determine whether a 
stream or wetland is jurisdictional by standing on their property. 
Rather, the commenter stated that property owners would need to 
determine the source and timing of flow, whether the stream flowed into 
a navigable water off-property, whether wetlands abutted a 
jurisdictional water, and whether a downstream segment lacked 
sufficient flow or otherwise broke jurisdiction. The commenter asserted 
that many of these inquiries would require the decision-maker to 
trespass onto properties of others, or guess. Furthermore, the 
commenter stated that in many cases, critical information that the rule 
required the property owner to know--such as whether a wetland is 
inundated by flooding from a jurisdictional water in a typical year--is 
not normally recorded. This comment is consistent with the agencies' 
experience that the 2020 NWPR did not ``provide[ ] clarity and 
predictability for Federal agencies, States, Tribes, the regulated 
community, and the public.'' See 85 FR 22252 (April 21, 2020). With 
respect to categorical exclusions, this rule retains and codifies a 
list of categorical exclusions, as did the 2020 NWPR and the 2015 Clean 
Water Rule. See further discussion in section IV.C.7 of this preamble. 
The challenges that the 2020 NWPR imposed to establish jurisdiction for 
features that it appears to define as jurisdictional, and that 
significantly affect the integrity of paragraph (a)(1) waters, further 
undermine the 2020 NWPR's viability as an alternative to this rule.
i. ``Typical Year'' Metric
    The ``typical year'' is a concept fundamental to many of the 2020 
NWPR's definitions. 85 FR 22273 (April 21, 2020). Under the rule, 
tributaries and lakes, ponds, and impoundments of jurisdictional waters 
were only jurisdictional if they had certain surface water connections 
with a traditional navigable water or the territorial seas at least 
once in a typical year. 33 CFR 328.3(c)(6), (12). Two categories of 
wetlands only met the adjacency test for jurisdiction if they had a 
surface water connection with other jurisdictional waters once in a 
typical year. 33 CFR 328.3(c)(1). As a scientific matter, the concept 
of ``typical year conditions,'' including precipitation normalcy, may 
be relevant to ensuring that certain surface water connections in 
natural streams are not being observed under conditions that are 
unusually wet or dry. In terms of implementation, the concept of 
precipitation normalcy is valid in certain contexts, such as to inform 
determinations as to the presence of a wetland. However, in many 
important contexts, available tools, including the tools the 2020 NWPR 
recommended, cannot reliably demonstrate the presence of surface water 
connections in a typical year, which are a necessary element of most 
categories of jurisdictional waters under the 2020 NWPR. For example, a 
recent

[[Page 3059]]

study by the Corps found that precipitation normalcy (as calculated 
based on the methodology described in the preamble to the 2020 NWPR) 
was neither a reliable predictor of streamflow normalcy, nor was it a 
precise predictor of streamflow percentiles, in an analysis of 
watersheds across the United States.\69\ These challenges undermine the 
2020 NWPR's claim that it enhanced the ``predictability and consistency 
of Clean Water Act programs.'' See 85 FR 22250 (April 21, 2020).
---------------------------------------------------------------------------

    \69\ Sparrow, K.H, Gutenson, J.L., Wahl, M.D. and Cotterman, 
K.A. 2022. Evaluation of Climatic and Hydroclimatic Resources to 
Support the US Army Corps of Engineers Regulatory Program. Engineer 
Research and Development Center (U.S.) Technical Report no. ERDC/CHL 
TR-22-19.
---------------------------------------------------------------------------

    One of the significant implementation challenges of the typical 
year metric is that it can be difficult and sometimes impossible to 
identify the presence of a surface water connection in a typical year. 
Such connections are often not apparent from visual field observation 
alone. For example, on the day of a visit to an intermittent stream 
that flows only several months or several weeks a year, it is very 
unlikely that an observer would see surface water flows connecting to a 
downstream jurisdictional water. Similarly, though many ponds or 
wetlands may be frequently inundated by flooding from another water, in 
arid areas those features may be inundated only a few times every year, 
and sometimes the inundation occurs on a single day or within a matter 
of hours. While these waters satisfy the 2020 NWPR's jurisdictional 
test, agency staff would probably not be able to determine that they 
do, given how unlikely they would be to observe these infrequent 
connections. The difficulty of finding the direct hydrologic 
connections required by the typical year concept during a field visit 
is exacerbated by the fact that the 2020 NWPR discouraged reliance on 
field indicators. See, e.g., id. at 22292 (``The agencies . . . 
conclude that physical indicators of flow, absent verification of the 
actual occurrence of flow, may not accurately represent the flow 
classifications required for tributaries under this rule.'').
    Given the insufficiency of visual field observations to assess the 
presence of a surface water connection as specified in the 2020 NWPR, 
under that rule agency staff often needed to expend substantial time 
and resources to try to obtain ancillary data to determine flow 
conditions at a particular site in a typical year. Hydrologic modeling 
tools and advanced statistical analyses could be employed where 
sufficient flow data are available, but often data needed to conduct 
such analyses is limited or lacking altogether, especially for smaller 
streams. Few streams across the country have hydrologic gages that 
continuously measure flow, as most such gages are located on larger 
rivers with perennial flow. Moreover, ``typical year conditions'' are 
often irrelevant to the extent of flow in human-altered streams, 
including effluent-dependent streams. The 2020 NWPR did not explain why 
human-altered hydrology should be subject to the same typical year 
requirement as natural streams.
    For the same reasons that agency staff are unlikely to witness the 
specific surface water connections required under the 2020 NWPR during 
a site visit in dry regions or during the dry season, they are also 
unlikely to capture evidence of a surface water connection between a 
stream and a downstream traditional navigable water or the territorial 
seas using available aerial photographs taken during typical year 
conditions. Aerial photographs are often taken just once per year or 
once every other year and staff have no way of ensuring that they were 
taken during a typical year. High-resolution satellite imagery can 
serve as a reliable source to demonstrate specific surface water 
connections. But the availability and usability of such imagery varies 
across the country, depending on access, update intervals, cloud cover, 
and land cover (i.e., vegetation or trees that obscure aerial views of 
stream channels, requiring the use of advanced tools to detect features 
of interest or the presence of water), so that such tools may be 
unlikely to demonstrate that specific surface water connections are 
occurring in a typical year. Moreover, as the 2020 NWPR acknowledged, 
``characteristics of tributaries may not be visible in aerial 
photographs'' taken during periods of ``high shrub or tree cover,'' 85 
FR 22299 (April 21, 2020). Commenters on the proposed rule stated that 
Tribes and States lacked sufficient data, aerial photography and access 
to other tools required to support the use of the typical year test in 
many locations. They expressed concern that under-resourced communities 
suffer a particular lack of data necessary to support this test. New 
satellites are expected to surmount some of these issues in the future, 
but as this information is not yet available, regulators could not use 
it to inform jurisdiction based on the requirements in the 2020 NWPR. 
Remote tools, such as aerial or satellite imagery, are often useful in 
implementing any definition of ``waters of the United States,'' but the 
2020 NWPR's typical year criteria made use of these resources 
particularly challenging.
    The same difficulties created challenges in detecting surface 
hydrologic connections that occurred in a typical year to meet the 2020 
NWPR's definition of ``adjacent wetlands'' or ``lakes and ponds, and 
impoundments of jurisdictional waters.'' The 2020 NWPR's standard of 
inundation by flooding in a typical year was not tied to any commonly 
calculated flood interval, such as flood recurrence intervals, and the 
agencies are not aware of a tool capable of collecting the type of 
inundation data the 2020 NWPR required. Demonstrating that a wetland, 
lake, pond, or impoundment is inundated by flooding once in a typical 
year would require a field visit or a high-quality aerial photograph or 
satellite image coinciding with the exact time that the flooding occurs 
from a tributary to a wetland, lake, pond, or impoundment, as well as 
being able to demonstrate that this flooding occurred in a typical 
year. Determining that inundation by flooding occurs in a typical year 
was therefore extremely difficult, and sometimes impossible. 
Demonstrating that an artificial feature allows for a direct hydrologic 
surface connection between a wetland and a tributary in a typical year 
posed similar obstacles, requiring either auspiciously timed field 
visits, aerial photography, high-resolution satellite imagery, or data 
that the agencies may not be able to access, such as construction plans 
or operational records for an artificial levee.
    The 2020 NWPR suggested the agencies ``will generally use'' 
precipitation data from the National Oceanic and Atmospheric 
Administration (NOAA) to help determine the presence of a surface water 
connection in a typical year, see 85 FR 22274 (April 21, 2020), but the 
methodology described in the 2020 NWPR preamble for determining 
precipitation in a typical year made it difficult to use these data to 
inform jurisdiction. NOAA precipitation totals over the three months 
prior to a site observation are compared to precipitation totals 
observed over the preceding 30 years to determine if conditions were 
wetter than normal, drier than normal, or normal (``typical''). Using 
the methodology in the preamble of the 2020 NWPR, only 40% of 
observations over a rolling 30-year period of record are considered 
``normal,'' while 30% of observations are considered to be ``wetter 
than normal'' and 30% of observations are considered to be ``drier than 
normal.'' If

[[Page 3060]]

surface water flow was observed during normal or dry conditions, the 
agencies could have higher confidence that the surface water 
observations represented flow in a ``typical year.'' However, if flow 
was observed during the 30% of conditions that are ``wetter than 
normal,'' the surface water observations did not reveal whether flow 
would occur during a typical year. And if flow was not observed, 
precipitation data from the previous three months did not indicate 
whether flow might occur in that particular water feature under typical 
year conditions at a different point in the year. Therefore, if a site 
visit was conducted when surface water flow was not present, the 
agencies' suggested approach for evaluating whether a feature meets the 
typical year test often did not provide meaningful and relevant 
information for the agencies to make accurate determinations of 
jurisdiction. Indeed, a commenter on the proposed rule emphasized that 
Tribes and States have found the ``typical year'' requirement to 
require extensive hydrologic modeling and advanced statistical analyses 
in complex conditions. Under any regulatory regime, the agencies use a 
weight of evidence approach to determine jurisdiction, but the 2020 
NWPR typical year requirement placed onerous and, in many instances, 
arbitrary constraints on the data that can be used as evidence.
    Furthermore, the typical year concept as applied to the 2020 NWPR 
does not account for the increasing number of recurrent heat waves, 
droughts, storms, and other extreme weather events in many parts of the 
country. These events can have profound impacts on local and regional 
hydrology, including streamflow. Commenters noted that determining what 
is ``typical'' under the 2020 NWPR in light of increased drought and 
floods was not simple for Tribal or State agencies; such determinations 
required expert analysis and left much to interpretation, undermining 
the assertion by the agencies that the 2020 NWPR would establish a 
clear, predictable regulatory framework that can be implemented in the 
field.
    The concept of ``typical year'' in the 2020 NWPR sought to factor 
in long-term climatic changes over time to some degree by considering a 
thirty-year rolling period of data, see 33 CFR 328.3(c)(13). However, 
the 2020 NWPR did not allow the agencies flexibility to consider other 
time intervals when appropriate to reflect effects of a rapidly 
changing climate, including positive trends in temperature, increasing 
storm events, and extended droughts. In response to more rapid recent 
changes in climate, NOAA has developed alternative approaches for 
estimating climate normals, including seasonal averages computed using 
shorter, annually updated averaging periods for temperature (10-year 
seasonal average) and total precipitation (15-year seasonal average). 
The rigid rolling thirty-year approach to determining typical year in 
the 2020 NWPR did not allow the agencies to use these updated methods.
    The 2020 NWPR noted that the agencies can look to sources of 
information other than site visits, aerial photographs, and 
precipitation data to assess whether a feature has surface water flow 
in a typical year. It identified the Web-based Water-Budget Interactive 
Modeling Program, Climate Analysis for Wetlands Tables, and the Palmer 
Drought Severity Index, 85 FR 22275 (April 21, 2020). These methods, 
which provide information useful in many other contexts, often only 
look at climate-related conditions generally and often did not answer 
the jurisdictional questions posed by the 2020 NWPR. For example, they 
did not address whether surface water flow might connect a particular 
stream to a downstream traditional navigable water or the territorial 
seas, whether a particular wetland was inundated by or connected to a 
jurisdictional water as required under the 2020 NWPR, or how 
uncertainties at different locations and in different months affected 
the accuracy of condition estimates. While precipitation is an 
important factor, other information is also relevant to streamflow and 
surface water connections in a typical year, including the 
contributions of flow from wetlands, upgradient streams, and open 
waters in the watershed, evapotranspiration rates, water withdrawals 
including groundwater pumping, and other climatic conditions. Yet 
collecting this information from a variety of sources and interpreting 
it can be extremely time- and resource-intensive and may require 
special expertise. While the agencies have substantial experience using 
a weight of evidence approach to determine jurisdiction, for example as 
part of the significant nexus analysis, the typical year requirement 
makes it substantially more difficult to interpret available data and 
narrows the scope of data that can be used to determine jurisdiction.
    Finally, the challenges presented by determining the presence of 
surface water flow in a typical year are even greater when evaluating a 
tributary at a distance from the downstream traditional navigable water 
or the territorial seas. Even streams that flow perennially or 
intermittently often travel many miles prior to reaching the closest 
traditional navigable water or the territorial seas, meaning many 
downstream reaches may need to be assessed. Under the 2020 NWPR, any 
ephemeral reaches along that pathway that did not carry surface water 
flow once in a typical year would render all upstream waters non-
jurisdictional. 85 FR 22277 (April 21, 2020). The need to assess 
lengthy tributary systems imposed an extraordinarily high burden of 
proof on the agencies to evaluate surface water flow in a typical year 
along the flow path from a stream of interest to a downstream 
traditional navigable water or the territorial seas. The longer the 
pathway, the more challenging the analysis. As a commenter noted, in 
adopting the test, the 2020 NWPR inserted case-by-case analyses for 
every jurisdictional determination despite the rule's claim that it 
``provide[s] a predictable framework in which to establish federal 
jurisdiction.'' Id. at 22273-22274. The uncertainty and implementation 
challenges generated by the 2020 NWPR's foundational typical year test 
are yet another basis to replace that rule.
ii. Determining Adjacency
    The 2020 NWPR provided that wetlands are ``adjacent'' when they: 
(1) abut a traditional navigable water or the territorial seas; a 
tributary; or a lake, pond, or impoundment of a jurisdictional water; 
(2) are inundated by flooding from one of these waters in a typical 
year; (3) are physically separated from one of these waters only by a 
natural berm, bank, dune, or similar natural feature; or (4) are 
physically separated from one of these waters only by an artificial 
dike, barrier, or similar artificial structure so long as that 
structure allows for a direct hydrologic surface connection between the 
wetlands and the water in a typical year, such as through a culvert, 
flood or tide gate, pump, or similar artificial feature. 85 FR 22338; 
33 CFR 328.3(c)(1). In practice, agency staff have found several of 
these criteria for adjacency extremely difficult to implement in 
certain circumstances.
    The artificial barrier provision led to arbitrary results. For 
example, under the fourth way to meet the adjacency definition, a 
wetland may be jurisdictional if it is separated from a jurisdictional 
water by an artificial structure, such as a levee, that allows for a 
direct hydrologic surface connection in a typical year through a 
culvert. However, the same wetland would not be jurisdictional if there 
was no levee present, even if there was a direct

[[Page 3061]]

hydrological surface connection in a typical year through a culvert 
(assuming the wetland did not meet another criterion for adjacency). 
The 2020 NWPR therefore established that certain wetlands with a direct 
hydrologic surface connection to a jurisdictional water are only 
jurisdictional due to the presence of an artificial barrier. This 
discrepancy bears no relationship to the actual connections between the 
features at issue and is not supported by science or the agencies' 
experience.
    Moreover, the provision establishing that a wetland is ``adjacent'' 
if a jurisdictional water inundates it by flooding in a typical year 
was extremely difficult to implement. See 33 CFR 328.3(c)(1)(ii). 
Inundation by flooding in a typical year is not a metric that is 
normally recorded either by implementing agencies or the regulated 
community. Available models generally focus on flood recurrence 
intervals, which do not necessarily correspond to the likelihood of 
inundation by flooding in a given or typical year, and the agencies 
would typically be unable to demonstrate that these indicators reflect 
typical year conditions. Indeed, the 2020 NWPR acknowledged that 
inundation by flooding in a typical year could correspond to a variety 
of flood recurrence intervals depending on location, climate, season, 
and other factors. 85 FR 22311. Given the absence of existing records 
of inundation by flooding, determining whether inundation by flooding 
has occurred in a typical year is challenging in many circumstances.
    Compounding the challenge, the 2020 NWPR provided that wetlands can 
be jurisdictional if they are inundated by flooding from a 
jurisdictional water in a typical year--but inundation in the other 
direction, from the wetlands to the jurisdictional water, is not 
grounds for jurisdiction. Not only is there no scientific or legal 
basis for distinguishing between inundation of the wetland as opposed 
to inundation from the wetland, see Riverside Bayview, 474 U.S. at 134 
(upholding the Corps' assertion of jurisdiction over ``wetlands that 
are not flooded by adjacent waters [but] may still tend to drain into 
those waters''), but determining whether the limited available 
photographs or other evidence of inundation reflects flooding in one 
direction as opposed to another adds to the difficulty in evaluating 
whether this standard is met. The same challenges apply to determining 
whether lakes, ponds, or impoundments of jurisdictional waters are 
inundated by flooding in a typical year, one basis for demonstrating 
Clean Water Act jurisdiction over these features. 85 FR 22338-39 (April 
21, 2020); 33 CFR 328.3(c)(vi).
iii. Ditches
    Among other requirements, the 2020 NWPR provided that a ditch \70\ 
is jurisdictional as a tributary if it was originally built in a 
tributary or adjacent wetland, as those terms are defined in the 2020 
NWPR, and emphasized that the agencies bear the burden of proof to 
determine that a ditch was originally constructed in a tributary or 
adjacent wetland. 33 CFR 328.3(a)(2), (c)(12); 85 FR 22299. In other 
words, in order to find a ditch jurisdictional, the agencies had to 
demonstrate that a ditch was (1) originally constructed in a stream (2) 
that, at the time of construction, had perennial or intermittent flow 
and (3) a surface water connection to a downstream traditional 
navigable water or the territorial seas (4) in a ``typical year.'' 
Alternatively, the agencies had to show that a ditch was (1) originally 
constructed in a wetland (2) that either abutted or had certain surface 
hydrologic connections to a jurisdictional water at the time the ditch 
was constructed (3) in a ``typical year,'' in order to demonstrate that 
the ditch is jurisdictional. Americans have been building ditches, 
straightening streams, and draining wetlands for hundreds of years. And 
while under earlier guidance and practice, the agencies generally 
assessed whether a ditch was excavated in dry land when making a 
jurisdictional determination, that involved an assessment simply of 
whether the ditch was excavated in a stream, a wetland, or other 
aquatic resource. By contrast, to determine whether a ditch was 
jurisdictional under the 2020 NWPR, the agencies had to determine if it 
was originally built in a tributary or adjacent wetland that would have 
been jurisdictional under the 2020 NWPR, and therefore had to address 
all of the implementation challenges discussed in the preceding 
sections involved in determining surface water connections and wetland 
adjacency in a typical year--but often for ditches built twenty, one 
hundred, or even several hundred years ago. To the extent that sparse 
evidence is available to demonstrate a surface water connection in a 
typical year for tributaries using tools available today, evidence is 
even more difficult to find when looking so far back in time. States 
approached the agencies seeking assistance in assessing the 
jurisdictional status of ditches, but the agencies were often unable to 
provide meaningful help given the burdens imposed by the 2020 NWPR's 
ditch definition.
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    \70\ Ditches perform many of the same functions as natural 
tributaries. For example, like natural tributaries, ditches that are 
part of the stream network convey water that carries nutrients, 
pollutants, and other constituents, both good and bad, to downstream 
traditional navigable waters, the territorial seas, and interstate 
waters.
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    The 2020 NWPR also provided that ditches are jurisdictional if they 
relocate a tributary, as that term was defined in the rule, 85 FR 22341 
(April 21, 2020); 33 CFR 328.3(a)(2), (c)(12), but this standard as 
defined by the 2020 NWPR was also often extremely difficult to assess. 
The 2020 NWPR explained that a relocated tributary is ``one in which an 
entire portion of the tributary may be moved to a different location.'' 
85 FR 22290 (April 21, 2020) (emphasis added). In other words, the 2020 
NWPR appeared to require a ditch to divert 100% of the tributary's flow 
to meet the ``relocate a tributary'' test. While prior rules have 
defined relocated tributaries as jurisdictional, the requirement that 
the entire portion be relocated is new and has created substantial 
implementation challenges. As a practical matter, when a tributary is 
relocated it often reroutes just a portion of its flow to the ditch. 
Assessing whether a ditch relocated 100% of a tributary's flow, as 
opposed to 80% or 50% of its flow, is extremely difficult and may not 
be possible in some circumstances. The scientific literature indicates 
that features like ditches that convey water continue to connect to and 
affect downstream waters. See section III.A.iv of the Technical Support 
Document for additional information. By establishing a jurisdictional 
standard that is extremely difficult to meet, the 2020 NWPR effectively 
removed from the protections of the Clean Water Act large numbers of 
ditches that function as tributaries and that significantly affect the 
integrity of downstream traditional navigable waters, the territorial 
seas, and interstate waters. As is the case with tributaries, lakes and 
ponds, impoundments, and wetlands, the 2020 NWPR's impracticable 
approach to ditches made it extremely difficult to implement. In the 
agencies' judgment, any efficiencies the 2020 NWPR may have achieved 
through categorical exclusions are outweighed by the challenges the 
agencies encountered in implementing the rule, coupled with its failure 
to implement the objective of the Clean Water Act by removing 
protections for waters that are properly within the statute's scope.

[[Page 3062]]

d. The 2020 NWPR Substantially Reduced Clean Water Act Protections Over 
Waters
    The failure of the 2020 NWPR to advance the objective of the Clean 
Water Act, as well as its inconsistency with science and the challenges 
it presents in implementation, have had real-world consequences. The 
agencies have found that substantially fewer waters were protected by 
the Clean Water Act under the 2020 NWPR compared to under previous 
rules and practices. It is important to note that the definition of 
``waters of the United States'' affects most Clean Water Act programs 
designed to restore and maintain water quality--including not only the 
section 402 NPDES and section 404 dredged and fill permitting programs, 
but also water quality standards under section 303, identification of 
impaired waters and total maximum daily loads under section 303, 
section 311 oil spill prevention, preparedness, and response programs, 
and the section 401 Tribal and State water quality certification 
programs--because the Clean Water Act provisions establishing such 
programs use the term ``navigable waters'' or ``waters of the United 
States.'' While the 2020 NWPR was promulgated with the expressed intent 
to decrease the scope of Federal jurisdiction, the agencies now are 
concerned that the actual decrease in water resource protections was 
more pronounced than the qualitative predictions in the 2020 NWPR 
preamble and supporting documents anticipated and acknowledged to the 
public. These data support the agencies' conclusion that the 2020 NWPR 
is not a suitable alternative to this rule.
i. Jurisdictional Determination and Permitting Data Show a Large Drop 
in the Scope of Waters Protected Under the Clean Water Act
    Through an evaluation of jurisdictional determinations completed by 
the Corps between 2016 and 2021,\71\ EPA and the Army have identified 
consistent indicators of a substantial reduction in waters protected 
under the Clean Water Act by the 2020 NWPR (see Technical Support 
Document section II.B.i for additional discussion on methods and 
results of the agencies' analyses). These indicators include an 
increase in the number and proportion of jurisdictional determinations 
completed where aquatic resources were found to be non-jurisdictional, 
an increase in determinations made by the Corps that no Clean Water Act 
section 404 permit is required for specific projects, and an increase 
in requests for the Corps to complete approved jurisdictional 
determinations (AJDs), rather than preliminary jurisdictional 
determinations (PJDs) which treat a feature as jurisdictional. These 
trends all reflect the narrow scope of jurisdiction in the 2020 NWPR's 
definitions. Additionally, the agencies find that these indicators 
likely account for only a fraction of the 2020 NWPR's impacts, because 
many project proponents did not seek any form of jurisdictional 
determination for waters that the 2020 NWPR categorically excluded, 
such as ephemeral features, and the Corps would not have knowledge of 
or ability to track such projects. A closer look at each of these 
indicators will help demonstrate some of the more pronounced impacts of 
the 2020 NWPR on paragraph (a)(1) waters than were identified for the 
public in the 2020 NWPR and its supporting documents. As explained in 
detail above, when a water falls outside the scope of the Clean Water 
Act, that means, among other things, that no Federal water quality 
standards will be established, and no Federal permit will be required 
to control the discharge of pollutants, including dredged or fill 
material, into such waters unless the pollutants reach jurisdictional 
waters. And since many entities did not believe that they would need to 
seek a jurisdictional determination under the 2020 NWPR, it is 
impossible to fully understand the scope of degradation the 2020 NWPR's 
definition caused to paragraph (a)(1) waters.
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    \71\ A jurisdictional determination is a written Corps 
determination that a water is subject to regulatory jurisdiction 
under section 404 of the Clean Water Act (33 U.S.C. 1344) or a 
written determination that a water is subject to regulatory 
jurisdiction under section 9 or 10 of the Rivers and Harbors Act of 
1899 (33 U.S.C. 401 et seq.). Jurisdictional determinations are 
identified as either preliminary or approved, and both types are 
recorded in determinations through an internal regulatory management 
database, called Operation and Maintenance Business Information 
Link, Regulatory Module (ORM2). This database documents Department 
of the Army authorizations under Clean Water Act section 404 and 
Rivers and Harbors Act section 10, including permit application 
processing and jurisdictional determinations. This database does not 
include aquatic resources that are not associated with a 
jurisdictional determination or that are not associated with 
alternatives to jurisdictional determinations (such as delineation 
concurrences or ``No jurisdictional determination required'' 
findings, where the Corps finds that a jurisdictional determination 
is not needed for a project), or permit request or resource impacts 
that are not associated with a Corps permit or enforcement action. 
An approved jurisdictional determination (AJD) is an official Corps 
document stating the presence or absence of ``waters of the United 
States'' on a parcel or a written statement and map identifying the 
limits of ``waters of the United States'' on a parcel. A preliminary 
jurisdictional determination (PJD) is a non-binding written 
indication that there may be ``waters of the United States'' on a 
parcel; an applicant can elect to use a PJD to voluntarily waive or 
set aside questions regarding Clean Water Act jurisdiction over a 
particular site and thus move forward assuming all waters will be 
treated as jurisdictional without making a formal determination.
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    Consistent with Executive Order 13990, EPA and Army staff have 
reviewed jurisdictional determinations as recorded in the Corps' 
internal regulatory management database, referred to as the ORM2 
database,\72\ to identify any noticeable trends in jurisdictional 
determinations under the past recent rules defining ``waters of the 
United States.'' The agencies found within the AJDs completed under the 
2020 NWPR, the probability of finding resources to be non-
jurisdictional increased precipitously. Of the 9,399 AJDs completed by 
the Corps under the 2020 NWPR during the first 12 months in which that 
rule was in effect,\73\ the agencies found approximately 75% of AJDs 
completed had identified non-jurisdictional water resources and 
approximately 25% of AJDs completed identified jurisdictional 
waters.\74\ Conversely, when the 1986 regulations and applicable 
guidance were in effect (including following the 2019 recodification of 
those regulations), substantially more jurisdictional waters were 
identified in AJDs on average per year than compared to the first 
twelve months of the 2020 NWPR.\75\ During similar one-year calendar 
intervals when the 1986 regulations and applicable guidance were in 
effect, approximately 28% to 45% of AJDs completed identified non-
jurisdictional aquatic resources, and 56% to 72% of AJDs identified 
jurisdictional resources.

[[Page 3063]]

The change from a range of 28% to 45% non-jurisdictional AJD findings 
prior to the 2020 NWPR to 75% non-jurisdictional findings after 
issuance of the 2020 NWPR indicates that substantially fewer waters 
were protected by the Clean Water Act under the 2020 NWPR (see 
Technical Support Document section II.B.i for additional discussion). 
Again, as commenters on the proposed rule noted, these numbers do not 
account for the many entities that did not seek AJDs because they 
believed their features were excluded under the 2020 NWPR.
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    \72\ See supra note 71.
    \73\ These AJDs were completed by the Corps between the 2020 
NWPR's effective date of June 22, 2020, and June 21, 2021.
    \74\ This excludes dryland AJDs and waters identified as 
jurisdictional only under section 10 of the Rivers and Harbors Act. 
In addition, under the 2020 NWPR, a single AJD in the Corps' 
database can include both affirmative and negative jurisdictional 
determinations. Under prior regulatory regimes, the Corps' database 
was structured such that a single AJD could be either affirmative, 
or negative, but not both. To account for this change in the 
structure of the database, a 2020 NWPR jurisdictional determination 
that includes both affirmative and negative jurisdictional resources 
was normalized and counted as two separate AJDs, one affirmative and 
one negative. The total number of AJDs considered after this process 
was carried out was 9,399. Prior to this normalization, the total 
number of AJDs considered was 7,769. More details on the agencies' 
analysis can be found in the Technical Support Document section 
II.B.i.
    \75\ The time periods evaluated were June 22, 2016 to June 21, 
2017; June 22, 2017 to June 21, 2018; and December 23, 2019 to June 
21, 2020. The date ranges here constitute periods of time when the 
1986 regulations (including the 2019 Repeal Rule's recodification of 
those regulations) and applicable guidance were in effect 
nationally. 2015 Clean Water Rule determinations were not part of 
this analysis.
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    When evaluating the effect of the 2020 NWPR on the number of 
individual aquatic resources (as opposed to the AJDs completed), the 
agencies found a similar substantial reduction in protections provided 
by the Clean Water Act. Within the first twelve months of 
implementation of the 2020 NWPR, between June 22, 2020, and June 21, 
2021, the Corps documented the jurisdictional status of 48,313 
individual aquatic resources or water features through AJDs completed; 
of these individual aquatic resources, approximately 75% were found to 
be non-jurisdictional by the Corps. More specifically, 70% of streams 
and wetlands evaluated were found to be non-jurisdictional, including 
11,044 ephemeral features (mostly streams) and 15,675 wetlands. Ditches 
were also frequently found to be non-jurisdictional (4,706 individual 
exclusions), which is likely the result of the narrowed definition of 
tributary under the 2020 NPWR and the requirement that a ditch was only 
jurisdictional as a tributary if it was originally built in a tributary 
or adjacent wetland, as those terms are defined in the 2020 NWPR. By 
comparison, only 45% of aquatic resources were found to be non-
jurisdictional during similar year-long calendar intervals between 2016 
and 2020 under the pre-2015 regulatory regime.\76\ This increase in 
non-jurisdictional determinations, so that approximately 75% of water 
bodies are non-jurisdictional under the 2020 NWPR as opposed to only 
45% under the prior regulations, undermined the agencies' ability to 
provide a baseline of Federal protection for the integrity of the 
nation's waters.
---------------------------------------------------------------------------

    \76\ Based on the average annual percentage of non-
jurisdictional findings.
---------------------------------------------------------------------------

    Of particular concern to the agencies is the 2020 NWPR's 
disproportionate effect on arid regions of the country, as the aquatic 
resources in these regions predominantly consist of ephemeral features. 
Under the 2020 NWPR, more permittees across the country, including in 
the arid West, sought AJDs rather than PJDs, particularly for ephemeral 
features. Many more streams were evaluated and determined to be non-
jurisdictional through AJDs in the arid West, while the number of 
individual stream reaches considered under PJDs declined precipitously. 
As mentioned previously, project proponents who request an AJD obtain 
an official Corps document that states either that there are no 
``waters of the United States'' present on a parcel, or a statement 
that ``waters of the United States'' are present, accompanied by a map 
identifying their extent. In contrast, an applicant can elect to use a 
PJD to voluntarily waive or set aside questions regarding Clean Water 
Act jurisdiction over a particular site and thus move forward assuming 
all waters will be treated as jurisdictional without making a formal 
determination. There are time savings and sometimes cost savings 
associated with requesting a PJD in lieu of an AJD. A decline in the 
proportion of PJDs being requested under the 2020 NWPR indicates that 
fewer project proponents requested that aquatic resources on their 
project site be treated as if they were jurisdictional.
    In Arizona, the annual average number of individual stream reaches 
considered under PJDs and similar alternatives to AJDs between 2016 to 
2020 was 941, while under the 2020 NWPR in 2020-2021 it was only 
45.\77\ Compared to pre-2015 regulatory practice, under the 2020 NWPR, 
Arizona experienced an approximate 95% decrease in individual stream 
reaches being considered via PJDs and a 9-fold increase in individual 
stream reaches being considered via AJDs. Similar metrics for New 
Mexico show an 84% decrease in individual streams being considered via 
PJDs and a 28-fold increase in individual streams being considered via 
AJDs under the 2020 NWPR.
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    \77\ The AJD values associated with the 2020 NWPR fall outside 
of the 95% confidence interval calculated for annual data from 2016-
2020. Note that in New Mexico and Arizona, the 2015 Clean Water Rule 
was never implemented due to litigation stays. The PJD values 
associated with the 2020 NWPR do not fall outside of the 95% 
confidence interval calculated for annual data from 2016-2020; this 
is likely a product of scale. See the Technical Support Document 
section II.B.i for more analysis.
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    The number of stream reaches assessed in Arizona under AJDs 
compared to the number of evaluations completed nationwide was 
disproportionately high under the 2020 NWPR. The number of stream 
reaches assessed in Arizona constituted 9% of the total stream reaches 
assessed nationally and 13% of the ephemeral reaches assessed 
nationally over the first twelve months in which the 2020 NWPR was 
implemented.\78\ This increase in the number of AJDs sought in Arizona 
under the 2020 NWPR compared to the number of AJDs sought in Arizona 
between 2016 and 2020 likely reflects the desire of landowners to 
confirm that features on their property were ephemeral or otherwise 
excluded under that rule, though it is possible the pace of landowners 
seeking AJDs would have slowed to some extent over time. The agencies 
understand the drastic decline in the number of PJDs requested compared 
to AJDs in the arid West, and the simultaneous increase in the number 
of AJD non-jurisdictional findings in the arid West, to have been 
driven largely by the categorical exclusion of ephemeral streams from 
jurisdiction. PJDs assume jurisdiction, and under the 2020 NWPR project 
proponents were less likely to assume that ephemeral streams were 
jurisdictional.
---------------------------------------------------------------------------

    \78\ There were a total of 16,787 stream reaches assessed via 
AJDs nationwide between June 22, 2020 and June 21, 2021.
---------------------------------------------------------------------------

    The Corps' data show that in New Mexico, of the 263 streams 
assessed via AJDs in the first twelve months of implementation of the 
2020 NWPR (i.e., between June 22, 2020, to June 21, 2021), 100% were 
found to be non-jurisdictional ephemeral features.\79\ In Arizona, of 
the 1,525 streams assessed in AJDs in the first year of implementation 
of the 2020 NWPR, 1,518, or 99.5%, were found to be non-jurisdictional 
ephemeral resources. Eliminating these streams from jurisdiction under 
the 2020 NWPR also typically eliminated jurisdiction over wetlands 
which otherwise might meet adjacency criteria.
---------------------------------------------------------------------------

    \79\ These non-jurisdictional ephemeral resources are 
predominantly ephemeral streams, but a small portion may be swales, 
gullies, or pools.
---------------------------------------------------------------------------

    Some commenters asserted that the low percentage of jurisdictional 
AJD findings in Arizona under the 2020 NWPR does not have a 
statistically significant difference from the percentages of 
jurisdictional findings under the pre-2015 regulatory regime. The 
agencies agree that of Corps AJDs completed between 2016 and 2020, high 
percentages of streams in Arizona were found to be non-jurisdictional 
between 2016 and 2020. Proportionally, the non-jurisdictional findings 
via AJDs between 2016-2020 and the 2020 NWPR are similar. However, 
because the volume of streams assessed under AJDs in the arid West 
increased so substantially, there was a 10-fold increase in non-
jurisdictional findings for streams in Arizona and a 36-fold increase 
in non-jurisdictional findings for streams in

[[Page 3064]]

New Mexico following implementation of the 2020 NWPR. The average 
annual number of individual stream resources considered in AJDs in 
Arizona between 2016-2020 was 147 (of which 138 were determined non-
jurisdictional), compared to 1,525 stream reaches assessed under the 
2020 NWPR (of which 1,521 were determined non-jurisdictional accounting 
for all exclusions). Assessed together, the statistically significant 
increase in overall resources assessed via AJD combined with the shift 
away from requests for PJDs, as well as the consistent proportion of 
AJDs with non-jurisdictional findings indicates that many more project 
proponents viewed resources on their land as no longer ``waters of the 
United States'' under the 2020 NWPR. The agencies' analysis also 
reflects the scope of the streams that the 2020 NWPR left unprotected, 
which in many cases are vitally important to desert aquatic ecosystems 
and to the hydrologic integrity of watersheds. See section IV.A.2.c.i 
of this preamble.
    The Corps identified at least 368 projects from June 22, 2020, to 
June 21, 2021, through its ORM2 database that would have needed a Clean 
Water Act section 404 permit prior to the 2020 NWPR, but no longer did 
under the 2020 NWPR's definition of ``waters of the United States.'' 
\80\ Moreover, in comparing 2020-2021 to similar annual data from 2016-
2020 from implementation of the 1986 regulations consistent with 
Supreme Court case law, there was an average increase of over 100% in 
the number of projects determined to not require section 404 permits 
under the Clean Water Act due to activities not occurring in ``waters 
of the United States'' or activities occurring in waters that were 
deemed no longer ``waters of the United States'' due to the 2020 NWPR. 
The number of projects that did not require a section 404 permit under 
the 2020 NWPR was likely much greater than these numbers indicate 
because project proponents did not need to notify the Corps if they had 
already received an AJD that concluded waters in the review area were 
not ``waters of the United States,'' and because many project 
proponents would not have sought a jurisdictional determination or 
applied for a permit at all if they believed their aquatic resources 
were non-jurisdictional under the 2020 NWPR. Many projects could have 
occurred without consultation with the Corps due to the 2020 NWPR's 
narrow definition of ``waters of the United States'' and expansive non-
jurisdictional categories. Therefore, while the Corps' ORM2 data shed 
light on the trend and magnitude of impacts to the scope of 
jurisdiction under the 2020 NWPR, it is fair to assume that these 
impacts are an underestimate.\81\
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    \80\ This tracking method only applies when 100% of jurisdiction 
is lost under the 2020 NWPR (i.e., if even 1 aquatic resource out of 
100 that is proposed to be impacted remains jurisdictional, this 
method is not used). Additionally, this tracking method was a new 
database feature, which was not yet implemented uniformly across the 
United States, and is likely under-representative even for those 
cases in which 100% of jurisdiction was lost under the 2020 NWPR.
    \81\ Requests for AJDs and the jurisdictional dispositions of 
the aquatic resources evaluated as part of those AJDs are imperfect 
measures of activities that might affect those jurisdictional or 
non-jurisdictional aquatic resources. The AJD data in the Corps ORM2 
database generally contain only records for situations in which 
landowners or project proponents have requested jurisdictional 
determinations from the Corps or that are associated with an 
enforcement action, and thus do not represent all aquatic resources 
that exist within the United States. The proportion and specific 
types of aquatic resources evaluated for jurisdiction via AJDs 
varies both geographically and from year to year. In addition, the 
ORM2 data collected from AJDs conducted under different regulatory 
regimes have some metrics that are not directly comparable. 
Notwithstanding these limitations, the volume of ORM2 data on AJDs 
and associated aquatic resources is large and is tracked in a 
reasonably accurate fashion, and thus provides a reasonable estimate 
of overall trends and conditions on the ground. It represents the 
best data available to the agencies at this time.
---------------------------------------------------------------------------

    Many commenters cited the impacts referenced above as reasons to 
reject the 2020 NWPR's definition of ``waters of the United States.'' 
In addition, many commenters cited national-scale assessments of the 
number of waterbodies that lost protection under the 2020 NWPR as 
evidence of environmental harm. Some commenters noted that 51% of 
wetlands and 18% of streams lost protections.\82\ Other commenters 
stated that 4.8 million miles of streams and 16.3 million acres of non-
floodplain wetlands would be left without Federal level protections 
under the 2020 NWPR.\83\
---------------------------------------------------------------------------

    \82\ Contained in the Resource and Programmatic Assessment for 
the Proposed Revised Definition of ``Waters of the United States'' 
(Docket ID No. EPA-HQ-OW-2021-0602-0039).
    \83\ Commenters cited to the following scientific paper as 
support: C.R. Lane and E. D'Amico. Identification of putative 
geographically isolated wetlands of the conterminous United States, 
52 J Am Water Resource Association 705(2016); K. Fesenmyer et al., 
Large portion of USA streams lose protection with new interpretation 
of Clean Water Act. February 2021. Freshwater Science 40(1).
---------------------------------------------------------------------------

    Commenters provided many potential examples of the harms caused by 
the 2020 NWPR around the country. One commenter stated that in the 
Northwest, an estimated 9,165 miles of ephemeral streams in Oregon's 
Rogue River Basin that provide drinking water for the region, as well 
as habitat and spawning grounds for Federal threatened Southern Oregon/
Northern California Coast coho salmon and steelhead, would have lost 
protection under the 2020 NWPR. Another commenter stated that in the 
Midwest, protection would have been lost for an estimated 500 to 1,000 
miles of ephemeral and ditched streams that flow into the Niagara 
River, the channel that connects Lake Erie and Lake Ontario. The 
commenter also noted that following promulgation of the 2020 NWPR, two 
Great Lakes states finalized legislative action to further reduce 
protections under State law for waters excluded by the 2020 NWPR. One 
commenter asserted that up to 202,244 acres of wetlands located behind 
levees in Missouri would have been excluded from jurisdiction under the 
2020 NWPR because they are separated from jurisdictional waters by 
``upland or by dikes, barriers, or similar structures.'' The commenter 
stated that these wetlands provide flood control, habitats, and improve 
water quality. In the Mountain West, a commenter stated that over half 
of Colorado's streams and 22% of that State's remaining wetlands would 
have been excluded from jurisdiction under the 2020 NWPR. With respect 
to the Southeast, a commenter cited analyses demonstrating that 162,149 
acres of wetlands in Georgia's Chattahoochee watershed were vulnerable 
to losing protection under the 2020 NWPR. The same commenter noted 
that, in the Mid-Atlantic, over 100,000 acres of wetlands would have 
lost protection under the 2020 NWPR in Virginia's James River and 
Rappahannock River watersheds, which are vital to water quality in the 
Chesapeake Bay. Finally, in the Southwest, comments from the State of 
New Mexico estimated that under the 2020 NWPR, 25-45% of its Clean 
Water Act stormwater general permits and 50% of its individual permits 
would no longer be required. In Arizona, a commenter stated that 94% of 
all wetlands and flowlines in Arizona's Upper San Pedro Watershed would 
have lost protection under the 2020 NWPR.
    The agencies have not conducted an independent analysis to verify 
each of these comments but have carefully reviewed the concerns 
identified and the underlying analyses that commenters cited and found 
them generally consistent with the agencies' own findings about the 
impacts of the 2020 NWPR. These examples illustrate the quality and 
importance of the waters that lost protection under the 2020 NWPR. As 
commenters emphasized, waters that the 2020 NWPR categorically 
excluded, such as ephemeral streams and their associated wetlands and 
wetlands that did not

[[Page 3065]]

meet the 2020 NWPR's adjacency criteria, provide critical ecosystem 
services. The absence of Clean Water Act protections for such resources 
and any subsequent unregulated and unmitigated impacts to such 
resources would have caused cascading, cumulative, and substantial 
downstream harm. Commenters stated that, specifically, the 2020 NWPR 
would have reduced the extent to which waters filter out pollutants 
before they reach traditional navigable waters; reduced flood 
protections and water storage services, and increased flooding; harmed 
fisheries and hunting sites; destroyed bird and wildlife habitat, 
including habitats relied on by endangered species; and reduced the 
quality of drinking water. Commenters also stated that the reduction in 
federally protected waters under the 2020 NWPR could increase water 
pollution near low-income communities and communities of color in 
particular and that they could experience associated increases in 
health risk.
    The 2020 NWPR's removal of Federal protections from the nation's 
waters, and the resulting detriment to the services they provide, 
undermines the objective of the Clean Water Act, as discussed in 
section IV.A.2 of this preamble.
ii. Tribes and States Did Not Fill the Regulatory Gap Left by the 2020 
NWPR
    Some commenters asserted that the diminished scope of ``waters of 
the United States'' would not necessarily reduce protections for waters 
because Tribes, States, and local entities may regulate discharges even 
in the absence of Clean Water Act regulation. See section IV.A.3.b of 
this preamble. This perspective is consistent with the 2020 NWPR's 
emphasis that, in the face of a narrower scope of ``waters of the 
United States,'' ``the controls that States, Tribes, and local entities 
choose to exercise over their land and water resources'' would help to 
achieve the objective of the Clean Water Act. 85 FR 22259 (April 21, 
2020). Yet while some Tribes and States regulate ``waters of the 
Tribe'' or ``waters of the State'' more broadly than the Federal 
Government under their own laws, many newly non-jurisdictional waters 
under the 2020 NWPR were on Tribal lands or in States that do not 
regulate waters beyond those covered by the Clean Water Act. Under the 
2020 NWPR, discharges into these waters could have occurred without any 
restriction.
    As discussed in the Economic Analysis for the Final Rule, many 
Tribes and States do not regulate waters more broadly than the Clean 
Water Act. See Economic Analysis for the Final Rule, Chapter II; 2020 
NWPR Economic Analysis at 30-31. Contrary to the predictions made in 
the 2020 NWPR Economic Analysis, during the year in which the 2020 NWPR 
was in effect, the net change made by States was deregulatory in 
nature. Two States which had previously protected State waters beyond 
the scope of ``waters of the United States'' removed these expansive 
protections, and no States that lacked these broader protections 
established them. See 2020 NWPR Economic Analysis at 39-41 (estimating 
that certain States are likely to continue their current permitting 
practices for dredged and fill material) and the Economic Analysis for 
the Final Rule, Chapter II (indicating that two of those States reduced 
the scope of State clean water protections after the 2020 NWPR was 
finalized, and none of them formally expanded protections as a direct 
result of the 2020 NWPR).
    The agencies understand that revising State regulations and/or laws 
takes time, and the agencies do not know how some States might have 
responded if the 2020 NWPR had been in place for more than a year, but 
the agencies have no basis to expect that more States that currently 
lack protections beyond the 2020 NWPR Federal floor would have 
established them. Indeed, the External Environmental Economics Advisory 
Committee has stated that the model that the 2020 NWPR used to forecast 
State responses to that rule was overly optimistic with respect to the 
likelihood that States would address a Federal regulatory gap, in part 
based on the agencies' failure to fully consider States' responses to 
past changes to the definition of ``waters of the United States'' 
(e.g., only three States directly increased protective regulations in 
response to the decision in SWANCC that the use of ``isolated'' non-
navigable intrastate ponds by migratory birds was not by itself a 
sufficient basis for the exercise of Federal authority under the Clean 
Water Act, and the agencies' resulting change in implementation of the 
Act).\84\ Moreover, commenters, including State entities, asserted that 
the Federal Government provided no assistance or support for 
overburdened State agencies trying to compensate for the sudden 
suspension in Federal protections under the 2020 NWPR. Finally, States 
asserted that in the absence of robust Federal protections, even if 
they were to expend substantial resources addressing discharges within 
their borders, they would not be able to limit pollutants flowing in 
from other States that may not have established such controls.
---------------------------------------------------------------------------

    \84\ Prior to the 2016 Trump Administration, EPA's Science 
Advisory Board (SAB) had a subcommittee on environmental economics 
known as the Environmental Economics Advisory Committee (EEAC). When 
this committee was disbanded under the 2016 Administration, its 
members created an ad-hoc external committee. This External 
Environmental Economics Advisory Committee (E-EEAC) carried out an 
assessment of the economic analysis associated with the 2020 NWPR. 
See Keiser, D., S. Olmstead, K. Boyle, V. Flatt, B. Keeler, D. 
Phaneuf, J. Shapiro, and J. Shimshack (2020). Report on the Repeal 
of the Clean Water Rule and its Replacement with the Navigable 
Waters Protection Rule to Define Waters of the United States 
(WOTUS). December 2020. As of today, the EPA's SAB has reinstated 
the EEAC, which assessed the proposed rule's economic analysis as 
part of the SAB's review of the rule.
---------------------------------------------------------------------------

    The agencies are also not aware of any Tribes that expanded their 
clean water protections to compensate for a reduction in protections 
under the 2020 NWPR. During the agencies' Tribal consultation and 
coordination for this rulemaking process, Tribes overwhelmingly 
indicated they lack the independent resources and expertise to protect 
their waters and therefore rely on Clean Water Act protections. See 
Summary of Tribal Consultation and Coordination, available in the 
docket for this rule. This feedback is consistent with the concerns 
expressed during the 2020 NWPR rulemaking process. See, e.g., 85 FR 
22336-22337, April 21, 2020 (``[M]any Tribes may lack the capacity to 
create a [T]ribal water program under [T]ribal law, to administer a 
program, or to expand programs that currently exist. Other Tribes may 
rely on the Federal government for enforcement of water quality 
violations . . . .'').
    Given the limited capacity of many Tribes and States to regulate 
waters more broadly than the Federal Government and limited authority 
under Tribal and State law, the narrowing of Federal jurisdiction would 
mean that many discharges into the newly non-jurisdictional waters 
would no longer be subject to regulation, including permitting 
processes and mitigation requirements designed to protect the chemical, 
physical, and biological integrity of the nation's waters. The agencies 
have heard concerns from a broad array of co-regulators and 
stakeholders, including Tribes, States, scientists, and non-
governmental organizations, that corroborated the agencies' data and 
indicated that the 2020 NWPR's reduction in the jurisdictional scope of 
the Clean Water Act would cause substantial environmental harms, 
including to the quality of paragraph (a)(1) waters, that Tribes and 
States lack the authority or resources to address.

[[Page 3066]]

    In conclusion, the agencies do not find that the 2020 NWPR is a 
suitable alternative to this rule.

C. This Rule

1. Summary of This Rule
    This rule establishes the definition of ``waters of the United 
States'' for purposes of the Clean Water Act. For clarity, this rule is 
divided into three parts: jurisdictional waters, exclusions, and 
definitions. This section of the preamble addresses each provision of 
the rule and provides an explanation of the rule text, a response to 
significant comments, and the agencies' interpretation and 
implementation of the provisions of the rule.
    The ``waters of the United States'' are defined in paragraph (a) of 
this rule: (1) traditional navigable waters, the territorial seas, and 
interstate waters (``paragraph (a)(1) waters''); (2) impoundments of 
``waters of the United States'' (``paragraph (a)(2) impoundments''); 
(3) tributaries to traditional navigable waters, the territorial seas, 
interstate waters, or paragraph (a)(2) impoundments when the 
tributaries meet either the relatively permanent standard or the 
significant nexus standard (``jurisdictional tributaries''); (4) 
wetlands adjacent to paragraph (a)(1) waters; wetlands adjacent to and 
with a continuous surface connection to relatively permanent paragraph 
(a)(2) impoundments or to jurisdictional tributaries when the 
jurisdictional tributaries meet the relatively permanent standard; and 
wetlands adjacent to paragraph (a)(2) impoundments or jurisdictional 
tributaries when the wetlands meet the significant nexus standard 
(``jurisdictional adjacent wetlands''); and (5) intrastate lakes and 
ponds, streams, or wetlands not identified in paragraphs (a)(1) through 
(4) that meet either the relatively permanent standard or the 
significant nexus standard (``paragraph (a)(5) waters'').
    The ``relatively permanent standard'' means relatively permanent, 
standing or continuously flowing waters connected to paragraph (a)(1) 
waters, and waters with a continuous surface connection to such 
relatively permanent waters or to paragraph (a)(1) waters. The 
``significant nexus standard'' means waters that, either alone or in 
combination with similarly situated waters in the region, significantly 
affect the chemical, physical, or biological integrity of traditional 
navigable waters, the territorial seas, or interstate waters.
    Paragraph (b) of this rule contains the longstanding exclusions 
from the pre-2015 regulations, as well as additional exclusions based 
on well-established practice, from the definition of ``waters of the 
United States.'' Paragraph (c) of this rule provides definitions for 
terms used in this rule.
Paragraph (a): Jurisdictional Waters
    Paragraph (a)(1). This rule defines ``waters of the United States'' 
to include traditional navigable waters, the territorial seas, and 
interstate waters. The agencies are not making changes to the text or 
substance of the provisions of the 1986 regulations covering 
traditional navigable waters, the territorial seas, and interstate 
waters. The agencies are consolidating these three categories of waters 
into one paragraph at the beginning of the regulatory text. While 
combined into one paragraph, each category will remain distinct in 
separate subparagraphs. The agencies have concluded that this non-
substantive change streamlines the regulatory text and increases 
clarity. This streamlining is not a substantive change and does not 
alter the agencies' longstanding interpretation and implementation of 
these provisions.
    Paragraph (a)(2). This rule defines ``waters of the United States'' 
to include impoundments of ``waters of the United States.'' 
Impoundments are created by discrete structures (often human-built) 
like dams or levees that typically have the effect of raising the water 
surface elevation, creating or expanding the area of open water, or 
both. In this rule, the paragraph (a)(2) impoundments category provides 
that ``waters of the United States'' do not lose their jurisdictional 
status simply because they are impounded. In a change from the 1986 
regulations, waters that are jurisdictional under paragraph (a)(5) and 
that are subsequently impounded do not retain their jurisdictional 
status by rule under the paragraph (a)(2) impoundments provision, but 
may still be determined to be jurisdictional if they meet the 
requirements of a category of ``waters of the United States'' other 
than paragraph (a)(2) at the time of assessment (i.e., as a traditional 
navigable water, the territorial seas, interstate water, jurisdictional 
tributary, jurisdictional adjacent wetland, or paragraph (a)(5) water).
    Paragraph (a)(3). This rule defines ``waters of the United States'' 
to include tributaries of traditional navigable waters, the territorial 
seas, interstate waters, or paragraph (a)(2) impoundments when the 
tributaries meet either the relatively permanent standard or the 
significant nexus standard. As compared to the 1986 regulations, this 
rule adds the territorial seas to the list of waters to which a water 
may be a tributary and deletes intrastate lakes and ponds, streams, or 
wetlands not identified in paragraphs (a)(1) through (4) (the (a)(3) 
``other waters'' provision under the 1986 regulations) from the list.
    Paragraph (a)(4). Aquatic resources that meet this rule's 
definitions of ``wetlands'' and ``adjacent'' with regard to another 
jurisdictional water are assessed under this provision. The rule 
defines ``waters of the United States'' to include: (1) wetlands 
adjacent to traditional navigable waters, the territorial seas, or 
interstate waters; (2) wetlands adjacent to and with a continuous 
surface connection to relatively permanent paragraph (a)(2) 
impoundments or jurisdictional tributaries when the jurisdictional 
tributaries meet the relatively permanent standard; or (3) wetlands 
adjacent to paragraph (a)(2) impoundments or jurisdictional tributaries 
when the wetlands meet the significant nexus standard (``jurisdictional 
adjacent wetlands'').
    Paragraph (a)(5). This rule defines ``waters of the United States'' 
to include intrastate lakes and ponds, streams, or wetlands not 
identified in paragraphs (a)(1) through (4) that meet either the 
relatively permanent standard or the significant nexus standard. In 
this paragraph, the agencies are retaining the category from the 1986 
regulations sometimes referred to as ``(a)(3) waters'' or ``other 
waters,'' but with changes to reflect the agencies' determination of 
the statutory limits on the scope of ``waters of the United States'' 
informed by the law, the science, and agency expertise, in addition to 
consideration of extensive public comment on the proposed rule. Of 
particular importance, the agencies have replaced the 1986 regulation's 
broad Commerce Clause basis for jurisdiction for waters not identified 
in other provisions of the definition, with the relatively permanent 
standard and the significant nexus standard. In addition, the agencies 
have deleted the non-exclusive list of ``other waters'' in the 1986 
regulation. Under this provision in the rule, only ``intrastate lakes 
and ponds, streams, or wetlands not identified in paragraphs (a)(1) 
through (4)'' can be assessed for jurisdiction under the relatively 
permanent standard or significant nexus standard.
Paragraph (b): Exclusions
    The agencies are promulgating a number of exclusions from the 
definition of ``waters of the United States,'' including longstanding

[[Page 3067]]

exclusions for prior converted cropland and waste treatment systems, 
and exclusions for features that were generally considered non-
jurisdictional under the pre-2015 regulatory regime. The agencies are 
listing these exclusions in the regulatory text in a new paragraph (b), 
which consolidates the exclusions together in a single regulatory 
section. Under this rule, where a feature satisfies the terms of an 
exclusion, it is excluded from jurisdiction even where the feature 
would otherwise be jurisdictional under paragraphs (a)(2) through (5) 
of this rule. Paragraph (a)(1) waters are not subject to the 
exclusions. The exclusions are:
    (1) Waste treatment systems, including treatment ponds or lagoons, 
designed to meet the requirements of the Clean Water Act;
    (2) Prior converted cropland designated by the Secretary of 
Agriculture. The exclusion would cease upon a change of use, which 
means that the area is no longer available for the production of 
agricultural commodities. 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;
    (3) Ditches (including roadside ditches) excavated wholly in and 
draining only dry land and that do not carry a relatively permanent 
flow of water;
    (4) Artificially irrigated areas that would revert to dry land if 
the irrigation ceased;
    (5) Artificial lakes or ponds created by excavating or diking dry 
land to collect and retain water and which are used exclusively for 
such purposes as stock watering, irrigation, settling basins, or rice 
growing;
    (6) Artificial reflecting or swimming pools or other small 
ornamental bodies of water created by excavating or diking dry land to 
retain water for primarily aesthetic reasons;
    (7) Waterfilled depressions created in dry land incidental to 
construction activity and pits excavated in dry land for the purpose of 
obtaining fill, sand, or gravel unless and until the construction or 
excavation operation is abandoned and the resulting body of water meets 
the definition of waters of the United States; and
    (8) Swales and erosional features (e.g., gullies, small washes) 
characterized by low volume, infrequent, or short duration flow.
Paragraph (c): Definitions
    Paragraph (c) of this rule provides definitions for purposes of the 
rule. This rule contains several defined terms unchanged from the 1986 
regulations: the definitions of ``wetlands,'' ``adjacent,'' ``high tide 
line,'' ``ordinary high water mark,'' and ``tidal water.'' This rule 
defines the term ``significantly affect'' for purposes of determining 
whether a water meets the significant nexus standard to mean ``a 
material influence on the chemical, physical, or biological integrity 
of'' a paragraph (a)(1) water. Under this rule, waters, including 
wetlands, are evaluated either alone, or in combination with other 
similarly situated waters in the region, based on the functions the 
evaluated waters perform. This rule identifies specific functions that 
will be assessed and identifies specific factors that will be 
considered when determining whether the functions provided by the 
water, either alone or in combination, have a material influence on the 
integrity of a traditional navigable water, the territorial seas, or an 
interstate water. These factors include the distance from a paragraph 
(a)(1) water; hydrologic factors, such as the frequency, duration, 
magnitude, timing, and rate of hydrologic connections, including 
shallow subsurface flow; the size, density, or number of waters that 
have been determined to be similarly situated; landscape position and 
geomorphology; and climatological variables such as temperature, 
rainfall, and snowpack. The functions in this rule are indicators that 
are tied to the chemical, physical, or biological integrity of 
paragraph (a)(1) waters, including contribution of flow; trapping, 
transformation, filtering, and transport of materials (including 
nutrients, sediment, and other pollutants); retention and attenuation 
of floodwaters and runoff; modulation of temperature in paragraph 
(a)(1) waters; or provision of habitat and food resources for aquatic 
species located in paragraph (a)(1) waters.
    Section IV.C of this preamble also provides guidance on 
implementation of each provision of this rule. In implementing this 
rule, the agencies generally will consider first if a water qualifies 
as a paragraph (a)(1) water (i.e., a traditional navigable water, the 
territorial seas, or an interstate water). If a waterbody is determined 
to be a paragraph (a)(1) water, then it is jurisdictional with no need 
for further evaluation. If a water is not a paragraph (a)(1) water, the 
agencies generally will consider next whether any of the exclusions in 
paragraph (b) of this rule apply to the water. The exclusions in this 
rule do not apply to paragraph (a)(1) waters, and therefore, a 
traditional navigable water, the territorial seas, or an interstate 
water cannot be excluded under this rule, even if the water would 
otherwise meet the criteria for an exclusion.\85\ If a water does not 
qualify as a paragraph (a)(1) water and the agencies determine that an 
exclusion is applicable (e.g., waters that meet the waste treatment 
system exclusion, wetlands that qualify as prior converted cropland), 
the water would not be jurisdictional under this rule. If the water is 
not a paragraph (a)(1) water, and an exclusion under paragraph (b) does 
not apply, then the agencies generally will determine next if the water 
can be assessed under paragraphs (a)(2) through (4) of this rule. If 
the water does not meet the criteria for paragraphs (a)(1) through (4), 
the agencies generally will assess next if the water is jurisdictional 
under paragraph (a)(5) of this rule. When assessing the jurisdictional 
status of waters after the effective date of the final rule, regulators 
and the public should use the definition of ``waters of the United 
States'' established by this rule. For example, when assessing whether 
a stream is a jurisdictional tributary, regulators and the public 
should consider the provisions related to tributaries in the final 
rule.\86\ If a water is not jurisdictional under paragraphs (a)(1) 
through (5) of this rule, then the water does not meet the definition 
of ``waters of the United States.''
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    \85\ See also discussion of the waste treatment system exclusion 
in section IV.C.7.b of this preamble, infra.
    \86\ The agencies will continue to evaluate potential 
enforcement actions using the regulations in place when the alleged 
violation occurred. For example, if a person excavated a ditch while 
the pre-2015 regulatory regime was in effect and the person complied 
with the terms of the pre-2015 regulatory regime, today's final rule 
does not create new liability. See United States v. Lucero, 989 F.3d 
1088 (9th Cir. 2021) (explaining that the 2020 NWPR did not apply 
retroactively to the defendant's violations, which occurred before 
the 2020 NWPR became effective).
---------------------------------------------------------------------------

    It is important to note that some aquatic resources can potentially 
be assessed for jurisdiction under multiple categories of this rule. 
For example, certain streams, rivers, lakes, ponds, wetlands, and 
impoundments can be assessed as traditional navigable waters or 
interstate waters under paragraph (a)(1)(i) or (a)(1)(iii) of this 
rule. Other streams, rivers, lakes, ponds, and impoundments are 
situated such that they are part of the tributary system and can be 
assessed under paragraph (a)(3) of this rule. The agencies will assess 
intrastate lakes and ponds, streams, and

[[Page 3068]]

wetlands under paragraph (a)(5) of this rule only if they do not fall 
within paragraphs (a)(1) through (4). In any case, the agencies will 
identify the provision or provisions of the rule under which a 
determination of jurisdiction is made.
    Section IV.C of this preamble provides increased clarity and 
substantial guidance to assist in implementing the relatively permanent 
standard and significant nexus standard. See sections IV.C.4, IV.C.5, 
and IV.C.6 of this preamble for additional information on how the 
agencies will implement these standards for tributaries, adjacent 
wetlands, and waters assessed under paragraph (a)(5) (these sections 
include guidance on identifying waterbodies on the landscape, 
determining which waters are ``relatively permanent, standing or 
continuously flowing,'' identifying waters with a ``continuous surface 
connection'' under the relatively permanent standard, and identifying 
which waters are ``similarly situated'' and ``in the region'' under the 
significant nexus standard).
    As is typical after a rule is promulgated, the agencies have 
entered into a joint agency coordination memorandum to ensure the 
consistency and thoroughness of the agencies' implementation of this 
rule, which is available in the docket for the final rule. See Docket 
ID No. EPA-HQ-OW-2021-0602. As part of these coordination procedures, 
EPA and Corps field staff will coordinate on all draft approved 
jurisdictional determinations based on the significant nexus standard, 
and the agencies will follow a process for elevating a subset of these 
determinations to EPA and Corps headquarters for review as necessary. 
That coordination will be enhanced for waters assessed under paragraph 
(a)(5), and headquarters at the agencies will review all draft approved 
jurisdictional determinations \87\ for paragraph (a)(5) waters based on 
the significant nexus standard. After nine months, the agencies will 
reevaluate this requirement and assess the implementation and 
coordination memorandum approach. See section IV.C.6 of this preamble 
for additional discussion.
---------------------------------------------------------------------------

    \87\ An approved jurisdictional determination is a Corps 
document stating the presence or absence of ``waters of the United 
States'' on a parcel or a written statement and map identifying the 
limits of ``waters of the United States'' on a parcel. See 33 CFR 
331.2.
---------------------------------------------------------------------------

    The agencies note that Congress exempted or excluded certain 
discharges from the Clean Water Act or from specific permitting 
requirements. This rule will not affect any of the exemptions, 
including exemptions from section 404 permitting requirements provided 
by section 404(f), such as those for normal farming, ranching, and 
silviculture activities. 33 U.S.C. 1344(f); 40 CFR 232.3; 33 CFR 323.4. 
This rule will also not affect the existing statutory or regulatory 
exemptions or exclusions from section 402 NPDES permitting 
requirements, such as for agricultural stormwater discharges and return 
flows from irrigated agriculture, or the status of water transfers. 33 
U.S.C. 1342(l)(1), (l)(2); 33 U.S.C. 1362(14); 40 CFR 122.2, 122.3(f). 
In addition, where waters are covered by the Clean Water Act, the 
agencies have adopted measures to simplify compliance with the Act such 
as general permits and tools for expediting the permitting process 
(e.g., mitigation banks, in-lieu fee programs, and functional/
conditional assessment tools). The agencies intend to continue to 
develop general permits and other simplified procedures to ensure that 
projects, particularly those that offer environmental or public 
benefits, can proceed with the necessary environmental safeguards while 
minimizing permitting delays.
    Finally, with respect to determining whether a water meets the 
definition of ``waters of the United States,'' under case law and the 
Corps' existing regulations ``[u]nauthorized discharges into waters of 
the United States do not eliminate Clean Water Act jurisdiction, even 
where such unauthorized discharges have the effect of destroying waters 
of the United States.'' 33 CFR 323.2 (1987). Thus, for example, an 
unpermitted discharge of fill material into a jurisdictional adjacent 
wetland that destroys all wetland characteristics does not render that 
water no longer jurisdictional. Nor does an authorized discharge, 
filling in a part of a tributary, for example, sever jurisdiction 
upstream, provided that the upstream waters meet the definition of 
``waters of the United States'' absent the unauthorized discharge.
2. Traditional Navigable Waters, the Territorial Seas, and Interstate 
Waters
a. This Rule
    The agencies are not making changes to the text or substance of the 
provisions of the 1986 regulations covering traditional navigable 
waters, the territorial seas, and interstate waters. The agencies are 
consolidating these three categories of waters into one paragraph at 
the beginning of the regulatory text. While combined into one 
paragraph, each category will remain distinct in separate 
subparagraphs. The agencies have concluded that this non-substantive 
change streamlines the regulatory text and increases clarity. This 
consolidation requires corresponding changes to cross references and 
the numbering of other provisions in the rule. These changes increase 
clarity by reducing the number of cross references necessary and make 
practical sense because the jurisdictional status of other categories 
of waters relies on their connection to traditional navigable waters, 
the territorial seas, or interstate waters. For example, the definition 
of ``significantly affect'' refers simply to ``the chemical, physical, 
or biological integrity of waters identified in paragraph (a)(1) of 
this section'' rather than requiring multiple cross-references to three 
separate paragraphs. This streamlining is not a substantive change and 
does not alter the agencies' longstanding interpretation and 
implementation of these provisions.
b. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    The agencies have concluded that the non-substantive change 
consolidating traditional navigable waters, the territorial seas, and 
interstate waters into paragraph (a)(1) streamlines the regulatory text 
and increases clarity. These changes increase clarity by reducing the 
number of cross references necessary and make practical sense because 
the jurisdictional status of other categories of waters relies on their 
connection to traditional navigable waters, the territorial seas, or 
interstate waters. The rationale for retaining each of these three 
water types is provided in the relevant subsections below.
    Some commenters expressed support for the categorical protection 
and consolidation of traditional navigable waters, the territorial 
seas, and interstate waters. One commenter stated that the 
consolidation is ``consistent with the history and text of the law.'' 
Several commenters opposed the consolidation of the traditional 
navigable waters, the territorial seas, and interstate waters 
provisions into one jurisdictional category, arguing that the 
categories of waters are distinct and therefore should remain separate. 
The agencies agree that each of these provisions is a distinct category 
but disagree that consolidating them into one paragraph has any effect 
on distinguishing the types of waters which fall within each category. 
Further, the agencies have kept the text of each category the same as 
in the 1986 regulations and have established separate subparagraphs for 
each category to ensure there is no confusion. The jurisdictional 
standards for each of

[[Page 3069]]

the three categories are different, so the agencies will clearly 
identify the subparagraph under which a particular water is 
jurisdictional. A water which meets the test for traditional navigable 
waters under the Clean Water Act, for example, will be identified as 
jurisdictional under paragraph (a)(1)(i). Note that some waters may 
fall into more than one category of paragraph (a)(1) waters (e.g., a 
water may be both a traditional navigable water and an interstate 
water, such as Lake Tahoe, or a water may be both a traditional 
navigable water and part of the territorial seas, such as the Pacific 
Ocean).
    A commenter stated that the protection of traditional navigable 
waters, the territorial seas, and interstate waters should not be 
affected by any exclusions that the agencies may include in this rule. 
The agencies agree and the text of this rule is clear that the 
exclusions do not apply to paragraph (a)(1) waters. See also section 
IV.C.7 of this preamble. The Clean Water Act fundamentally protects 
these three categories of waters: traditional navigable waters are 
clearly encompassed within the defined term ``navigable waters''; the 
territorial seas are explicitly mentioned in the definition of 
``navigable waters''; and, as discussed further below, interstate 
waters, by definition, are waters of the ``several States'' and are 
unambiguously ``waters of the United States.'' While the agencies have 
authority to draw lines excluding some aquatic features from the 
definition of ``waters of the United States,'' the Clean Water Act 
provides no such authority to the agencies to exclude waters in these 
three unambiguous types of ``waters of the United States'' under the 
statute. Even if jurisdiction over one or all of these categories of 
waters were ambiguous, the agencies have concluded that since these are 
the fundamental waters that Congress intended to protect under the 
Clean Water Act, and that have had longstanding and unequivocal 
protection, with the exception of the 2020 NWPR, it is reasonable to 
establish unequivocal jurisdiction over these waters. Further, the 
agencies have concluded that there are no policy, practical, or 
technical bases to apply the exclusions to these paragraph (a)(1) 
waters given their crucial role in the statutory regime.
    Some commenters expressed support for consolidating just 
traditional navigable waters and territorial seas into a single 
category of jurisdictional waters. A commenter added that this approach 
is logical because these two types of waters are the only types of 
waters that are explicitly referenced in the operative sections of the 
Clean Water Act. The commenter asserted that combining these waters 
into one category would make the rule clearer and easier to administer. 
Similarly, a couple of commenters expressed concerns that the proposed 
rule too broadly categorized what is considered a ``foundational'' 
water. The 2020 NWPR consolidated the categories of traditional 
navigable waters and the territorial seas in the definition of ``waters 
of the United States'' into a single paragraph in the regulatory text 
in order to streamline the text but deleted the interstate waters 
category. 85 FR 22280, 22338, 22340 (April 21, 2020). The agencies 
agree that combining these waters into one category makes the rule 
clearer and easier to administer. However, the agencies have also 
combined interstate waters into the same paragraph because, as 
discussed above, protecting all three categories of waters is a 
fundamental aim of the Clean Water Act. See section IV.C.2.b.iii of 
this preamble (discussing protection under the Clean Water Act of 
interstate waters in the same manner as traditional navigable waters 
and the territorial seas). Under this rule, the jurisdictional status 
of the other categories of waters relies on their connection to any one 
of these three categories of waters--a traditional navigable water, the 
territorial seas, or an interstate water (and, where required, meeting 
either the relatively permanent standard or the significant nexus 
standard). Therefore, the agencies have concluded that streamlining the 
rule by including all three categories of these waters in one paragraph 
is reasonable and appropriate.
    A commenter suggested that the agencies provide a definition of 
``foundational waters.'' The commenter suggested that ``if the common 
shorthand is that the waters used for commerce, the interstate 
waters[,] and the territorial seas are the `foundational waters[,]' 
then the additional term `foundational waters' should be defined as 
such.'' The commenter asserted that this would make the rule text 
easier to understand and use. The agencies are not providing a 
definition for ``foundational waters'' because they are not using the 
term ``foundational waters'' in the rule text. The agencies used the 
phrase ``foundational waters'' in the preamble to the proposed rule 
simply for convenience and readability rather than writing the phrase 
``traditional navigable waters, the territorial seas, and interstate 
waters'' repeatedly. As discussed above in this preamble, in light of 
the new consolidated paragraph that groups those three categories of 
waters together, the agencies will simply refer to those waters as 
``paragraph (a)(1) waters'' in this preamble.
i. Traditional Navigable Waters
(1) This Rule
    The Clean Water Act, the 1986 regulations, the 2015 Clean Water 
Rule, the 2019 Repeal Rule, and the 2020 NWPR all include within the 
scope of ``waters of the United States'' traditional navigable waters, 
defined by regulation as ``all waters which are currently used, or 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.'' E.g., 33 CFR 328.3(a)(1) (2014). With respect to 
traditional navigable waters, the text of the 1986 regulations and the 
text of the 2020 NWPR are identical. The agencies did not propose to 
amend the longstanding text defining ``traditional navigable waters'' 
and are not making changes to the text in this rule. As discussed 
above, the agencies are consolidating three categories of waters into 
one paragraph at the beginning of the regulatory text, and with this 
consolidation, ``traditional navigable waters'' are identified in 
paragraph (a)(1)(i) of this rule.
    The agencies also are not making changes to their longstanding 
interpretation of traditional navigable waters for purposes of Clean 
Water Act jurisdiction. Thus, these paragraph (a)(1)(i) waters include 
all of the ``navigable waters of the United States,'' defined in 33 CFR 
part 329 and by numerous decisions of the Federal courts, plus all 
other waters that are navigable-in-fact (e.g., the Great Salt Lake, 
Utah and Lake Minnetonka, Minnesota). To determine whether a waterbody 
constitutes a paragraph (a)(1)(i) water under the regulations, relevant 
considerations include the agencies' regulations; prior determinations 
by the Corps, by EPA, and by the Federal courts; and case law. The 
agencies will determine whether a particular waterbody is a traditional 
navigable water based on application of those considerations to the 
specific facts in each case.
    As noted above, the paragraph (a)(1)(i) waters include, but are not 
limited to, the ``navigable waters of the United States.'' A water body 
qualifies as a ``navigable water of the United States'' if it meets any 
of the tests set forth in 33 CFR part 329 (e.g., the waterbody is (a) 
subject to the ebb and flow of the tide, and/or (b) the waterbody is

[[Page 3070]]

presently used, or has been used in the past, or may be susceptible for 
use (with or without reasonable improvements) to transport interstate 
or foreign commerce).
    Traditional navigable waters also include ``all waters that are 
currently used, or 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.'' Some examples of waters that 
will be considered traditional navigable waters, and thus 
jurisdictional under this provision of this rule include: waters 
currently being used for commercial navigation, including commercial 
waterborne recreation (for example, boat rentals, guided fishing trips, 
or water ski tournaments); waters that have historically been used for 
commercial navigation, including commercial waterborne recreation; or 
waters that are susceptible to being used in the future for commercial 
navigation, including commercial waterborne recreation. See ``Waters 
that Qualify as Traditional Navigable Waters Under Section (a)(1) of 
the Agencies' Regulations,'' \88\ available at https://www.epa.gov/wotus/waters-qualify-traditional-navigable-waters-under-section-a1-agencies-regulations.
---------------------------------------------------------------------------

    \88\ ``Waters that Qualify as Traditional Navigable Waters Under 
Section (a)(1) of the Agencies' Regulations,'' began as ``Waters 
that Qualify as Waters of the United States Under Section (a)(1) of 
the Agencies' Regulations'' in Appendix D to the U.S. Army Corps of 
Engineers Jurisdictional Determination Form Instructional Guidebook 
(available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2316) that was published in 2007 
concurrently with the 2007 Rapanos Guidance and thus is often simply 
referred to as ``Appendix D.'' The Rapanos Guidance was updated in 
2008, but Appendix D has remained unchanged since 2007. Paragraph 
(a)(1)(i) of this rule was paragraph (a)(1) of the regulations in 
place when the guidance was issued, but the text of that provision 
has not changed through the various rulemakings defining ``waters of 
the United States,'' and the agencies have continued to use the 
guidance for determining whether a water is a ``traditional 
navigable water.'' See 80 FR 37054, 37074 (June 29, 2015) (2015 
Clean Water Rule); 85 FR 22250, 22281 (April 21, 2020) (2020 NWPR). 
There have been no substantive changes to the guidance since it was 
issued on May 30, 2007. In 2021, EPA and the Army established 
``Waters that Qualify as Waters of the United States Under Section 
(a)(1) of the Agencies' Regulations,'' as a standalone guidance 
document when rescinding a memorandum on traditional navigable 
waters finalized after the 2020 NWPR. However, for clarity the 
agencies have updated the title to ``Waters that Qualify as 
Traditional Navigable Waters Under Section (a)(1) of the Agencies' 
Regulations'' and deleted references to the Rapanos Guidance. The 
agencies will continue to use this guidance to determine whether a 
water is a ``traditional navigable water'' for the purposes of the 
Clean Water Act and the agencies' implementing regulations. This 
document is available at https://www.epa.gov/wotus/waters-qualify-traditional-navigable-waters-under-section-a1-agencies-regulations.
---------------------------------------------------------------------------

2) Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    Supreme Court decisions have not questioned the inclusion of 
traditional navigable waters in the definition of ``waters of the 
United States.'' See, e.g., SWANCC, 531 U.S. at 172 (``The term 
`navigable' has at least the import of showing us what Congress had in 
mind as its authority for enacting the CWA: its traditional 
jurisdiction over waters that were or had been navigable in fact or 
which could reasonably be so made.'').
    Some commenters voiced support for the agencies' decision to 
interpret the scope of traditional navigable waters consistent with the 
agencies' longstanding approach in the document known as ``Waters that 
Qualify as Waters of the United States Under Section (a)(1) of the 
Agencies' Regulations.'' A commenter added that such an interpretation 
is consistent with the agencies' longstanding guidance and is familiar 
to Tribal and State co-regulators as well as the general public. 
Another commenter stated that the agencies' reference to ``Waters that 
Qualify as Waters of the United States Under Section (a)(1) of the 
Agencies' Regulations'' would create additional confusion during the 
implementation of this rule. The agencies are maintaining their 
longstanding approach to traditional navigable waters for purposes of 
the Clean Water Act as reflected in this well-established document. The 
agencies have used this guidance since 2007 and through a number of 
rulemakings. The 2020 NWPR continued use of this guidance, stating, 
``because the agencies have not modified the definition of `traditional 
navigable waters,' the agencies are retaining [`Waters that Qualify as 
Waters of the United States Under Section (a)(1) of the Agencies' 
Regulations'] to help inform implementation of that provision of this 
final rule.'' 85 FR 22281 (April 21, 2020). Given the longstanding use 
of the guidance, the agencies do not think it will cause confusion to 
continue to use it. To provide additional clarity, however, the 
agencies are maintaining this document as standalone guidance titled 
``Waters that Qualify as Traditional Navigable Waters Under Section 
(a)(1) of the Agencies' Regulations,'' with minor edits to the title 
and to reflect that the Rapanos Guidance is no longer in effect, 
simultaneously with this rule.
    After the 2020 NWPR was promulgated, the agencies issued a 
coordination memorandum that created some confusion. ``U.S. 
Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers 
(Corps) Process for Elevating and Coordinating Specific Draft 
Determinations under the Clean Water Act (CWA)'' (hereinafter, ``TNW 
Coordination Memorandum''). The memorandum established an 
implementation process by which the agencies elevate to their 
headquarters certain case-specific and stand-alone Clean Water Act 
traditional navigable water determinations concluding that a water is 
``susceptible to use'' solely based on evidence of recreation-based 
commerce. Id. The TNW Coordination Memorandum merely required enhanced 
coordination for such determinations and did not state that a 
``susceptible to use'' determination could not be solely based on 
evidence of recreation-based commerce. On November 17, 2021, the 
agencies rescinded the TNW Coordination Memorandum but kept in place 
the ``Waters that Qualify as Waters of the United States Under Section 
(a)(1) of the Agencies' Regulations.'' \89\ A few commenters asserted 
that recreational activities are sufficient evidence to demonstrate 
that a water is susceptible to being used in the future for commercial 
navigation, thereby qualifying waters supporting recreational 
activities as traditional navigable waters for purposes of the Clean 
Water Act. Alternatively, several commenters asserted that recreational 
activities are not sufficient evidence to demonstrate that a water is a 
traditional navigable water. The Supreme Court has been clear that 
``[e]vidence of recreational use, depending on its nature, may bear 
upon susceptibility of commercial use.'' PPL Montana v. Montana, 565 
U.S. 576, 600-01 (2012) (in the context of navigability at the time of 
statehood); id. at 601 (``[P]ersonal or private use by boats 
demonstrates the availability of the stream for the simpler types of 
commercial navigation.'' (quoting United States v. Appalachian Elec. 
Power Co., 311 U.S. 377, 416 (1940))); id. (noting that the ``fact that 
actual use has `been more of a private nature than of a public, 
commercial sort . . . cannot be regarded as controlling''' (quoting 
United States v. Utah, 283 U.S. 64, 82

[[Page 3071]]

(1931))). Therefore, the agencies are maintaining their longstanding 
position that commercial waterborne recreation (for example, boat 
rentals, guided fishing trips, or water ski tournaments) can be 
considered when determining if a water is a traditional navigable 
water.
---------------------------------------------------------------------------

    \89\ U.S. Environmental Protection Agency and U.S. Department of 
the Army. ``Recission of June 30, 2020 Memorandum `U.S. 
Environmental Protection Agency (EPA) and U.S. Army Corps of 
Engineers (Corps) Process for Elevating and Coordination Specific 
Draft Determinations under the Clean Water Act (CWA).'' November 17, 
2021. Available at https://www.epa.gov/system/files/documents/2021-11/nwpr-tnw-coordination-rescission-memo_signed-11.17.2021.pdf.
---------------------------------------------------------------------------

    Some commenters stated that the agencies must ensure that 
traditional navigable waters are not limited to just the waters that 
the agencies have determined to be ``navigable waters of the United 
States'' under section 10 of the Rivers and Harbors Act of 1899. Other 
commenters stated that the agencies should limit the scope of 
traditional navigable waters to the section 10 waters under the Rivers 
and Harbors Act of 1899. The agencies are not changing their 
longstanding position that the traditional navigable waters for 
purposes of the Clean Water Act include, but are not limited to, the 
section 10 waters under the Rivers and Harbors Act of 1899, and include 
any of the waters that constitute traditional navigable waters under 
relevant judicial decisions. See ``Waters that Qualify as Waters of the 
United States Under Section (a)(1) of the Agencies' Regulations.'' \90\ 
The scope of the Rivers and Harbor Act of 1899 is generally narrower 
than the scope of the Clean Water Act. See, e.g., 1902 Atlantic Ltd. v. 
Hudson, 574 F. Supp. 1381, 1392-93 (E.D. Va. 1983) (explaining that 
``[t]he term `navigable waters of the United States' as used in the 
Rivers and Harbors Act of 1899 has a substantially different, and more 
limited, meaning than the term as used in the Clean Water Act'' and 
that ``the term has a more limited meaning, consistent with the 
concepts of `navigation' and `navigability' as of 1899''). The scope of 
``navigable waters of the United States'' under the Rivers and Harbors 
Act of 1899 is thus more limited than the scope of traditional 
navigable waters for purposes of the Clean Water Act and as established 
in paragraph (a)(1)(i) of this rule. The Corps' regulations reflect the 
difference and under the Corps' regulations, ``navigable waters of the 
United States'' (i.e., waters that are subject to section 10 of the 
Rivers and Harbors Act of 1899) are limited to ``those waters that are 
subject to the ebb and flow of the tide and/or are presently used, or 
have been used in the past, or may be susceptible for use to transport 
interstate or foreign commerce.'' 33 CFR 329.4. Therefore, there are 
numerous waters that have been determined to be traditional navigable 
waters for purposes of the Clean Water Act, or navigable for other 
purposes under Federal law, but which are not ``navigable waters of the 
United States'' under section 10 of the Rivers and Harbors Act of 1899. 
For example, the Supreme Court has found that the Great Salt Lake met 
the test for navigability for purposes of the ownership of the bed of 
the Lake at the time of Utah's statehood, even though it was not part 
of a continuous waterborne highway of interstate commerce, but the 
Court of Appeals for the Tenth Circuit found that evidence insufficient 
to establish that the Lake is covered by the Rivers and Harbors Act of 
1899. See Utah v. United States, 403 U.S. 9 (1971); Hardy Salt Co. v. 
Southern Pacific Trans. Co., 501 F.2d 1156 (10th Cir. 1974). The Corps 
has determined the lake to be a traditional navigable water for 
purposes of the Clean Water Act based on the Supreme Court's finding 
that the water in the past met the test for navigability. The 
distinction the agencies have drawn between section 10 waters and 
traditional navigable waters for purposes of the Clean Water Act is 
entirely consistent with Supreme Court case law. The Supreme Court in 
Kaiser Aetna rejected the notion ``that the concept of `navigable 
waters of the United States' has a fixed meaning that remains unchanged 
in whatever context it is being applied.'' Kaiser Aetna v. United 
States, 444 U.S. 164, 170 (1979). Instead, the Court cautioned that 
``any reliance upon judicial precedent must be predicated upon a 
careful appraisal of the purpose for which the concept of 
`navigability' was invoked in a particular case.'' Id. at 171 (internal 
quotation marks omitted) (emphasis in original). The Supreme Court 
further stated that the ``cases that discuss Congress' paramount 
authority to regulate waters used in interstate commerce are 
consequently best understood when viewed in terms of more traditional 
Commerce Clause analysis than by reference to whether the stream, in 
fact, is capable of supporting navigation or may be characterized as 
[a] `navigable water of the United States.''' Id. at 174. More 
recently, the Supreme Court has cautioned ``that the test for 
navigability is not applied in the same way in [different] types of 
cases[,]'' referring, for example, to cases arising under the Federal 
Power Act, Clean Water Act, and title disputes. PPL Montana v. Montana, 
565 U.S. 576, 592 (2012).
---------------------------------------------------------------------------

    \90\ See supra note 88.
---------------------------------------------------------------------------

    A number of commenters stated that the agencies' interpretation of 
traditional navigable waters was inconsistent with the test for 
navigability in The Daniel Ball, 77 U.S. 557 (1870), with the 
discussion of navigability in SWANCC, and with the plurality and 
Justice Kennedy's opinions in Rapanos. The agencies disagree. None of 
the opinions in Rapanos addressed the test for traditional navigable 
waters; rather, they simply cited to The Daniel Ball--the beginning of 
a long line of cases addressing navigability. As the Supreme Court has 
explained: ``The Daniel Ball formulation has been invoked in 
considering the navigability of waters for purposes of assessing 
federal regulatory authority under the Constitution, and the 
application of specific federal statutes, as to the waters and their 
beds.'' PPL Montana, 565 U.S. at 592 (citing The Montello, 20 Wall. 
430, 439 (1874); United States v. Appalachian Elec. Power Co., 311 U.S. 
377, 406 & n.21 (1940) (Federal Power Act); Rapanos, 547 U.S. at 730-31 
(plurality opinion) (Clean Water Act); id. at 761 (Kennedy, J., 
concurring in judgment) (same)). In PPL Montana, the Supreme Court was 
clear that the test for navigability has evolved since The Daniel Ball; 
it depends upon the authority being exercised by the Federal Government 
and is a case-specific inquiry. ``It should be noted, however, that the 
test for navigability is not applied in the same way in these distinct 
types of cases.'' 565 U.S. at 592. Of particular relevance for 
traditional navigable waters for the Clean Water Act, ``federal 
regulatory authority encompasses waters that only recently have become 
navigable, see, e.g., Philadelphia Co. v. Stimson, 223 U.S. 605, 634-
635, 32 S.Ct. 340, 56 L.Ed. 570 (1912), were once navigable but are no 
longer, see Economy Light & Power Co. v. United States, 256 U.S. 113, 
123-124, 41 S.Ct. 409, 65 L.Ed. 847 (1921), or are not navigable and 
never have been but may become so by reasonable improvements, see 
Appalachian Elec. Power Co., supra, at 407-408, 61 S.Ct. 291. With 
respect to the Federal commerce power, the inquiry regarding navigation 
historically focused on interstate commerce. See The Daniel Ball, 
supra, at 564. And, of course, the commerce power extends beyond 
navigation. See Kaiser Aetna v. United States, 444 U.S. 164, 173-174, 
100 S.Ct. 383, 62 L.Ed.2d 332 (1979). . . . Indeed, `[e]ach application 
of [the Daniel Ball] test . . . is apt to uncover variations and 
refinements which require further elaboration.' Appalachian Elec. Power 
Co., supra, at 406, 61 S.Ct. 291.'' PPL Montana, 565 U.S. at 592-93. 
Thus, the agencies' interpretation of traditional navigable waters for 
purposes of the Clean Water Act is consistent with The Daniel Ball as 
applied by the Supreme Court.

[[Page 3072]]

ii. Territorial Seas
(1) This Rule
    The Clean Water Act defines ``navigable waters'' to include ``the 
territorial seas'' in section 502(7). The Clean Water Act then defines 
the ``territorial seas'' in section 502(8) as ``the belt of the seas 
measured from the line of ordinary low water along that portion of the 
coast which is in direct contact with the open sea and the line marking 
the seaward limit of inland waters, and extending seaward a distance of 
three miles.'' The territorial seas establish the seaward limit of 
``waters of the United States'' and are clearly jurisdictional under 
the Clean Water Act.
    The Clean Water Act, the 1986 regulations, the 2015 Clean Water 
Rule, the 2019 Repeal Rule, and the 2020 NWPR all included ``the 
territorial seas'' as ``waters of the United States.'' This rule makes 
no changes to ``the territorial seas'' provision and retains the 
provision in the regulatory text, consolidated in paragraph (a)(1).
(2) Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    As described above, the Clean Water Act explicitly defines the 
agencies' jurisdiction to include ``the territorial seas.'' This rule 
confirms the agencies' jurisdiction over these waters, consistent with 
Congress's direction. A commenter stated that if the agencies combine 
traditional navigable waters, the territorial seas, and interstate 
waters into one category of waters in this rule, the agencies should 
clarify that the territorial seas represent a distinct basis for 
jurisdiction and are not a type of traditional navigable water. The 
agencies agree with this commenter that the territorial seas are an 
independent category of jurisdictional waters. However, in the preamble 
to the proposed rule, the agencies also stated that the territorial 
seas are a type of traditional navigable water. While most portions of 
the territorial seas are also traditional navigable waters, the 
agencies are clarifying in this rule that portions of the territorial 
seas that may not be navigable or capable of being used in interstate 
or foreign commerce are still jurisdictional if they meet the 
definition of the ``territorial seas'' in the Clean Water Act. The 
agencies did not intend to exclude any portion of the territorial seas 
as the term is defined in Clean Water Act section 502(8), 33 U.S.C. 
1362(8). To avoid any confusion, this rule continues to list 
traditional navigable waters and the territorial seas as separate 
categories of jurisdictional waters.
iii. Interstate Waters
(1) This Rule
    This rule retains the longstanding categorical protections for 
interstate waters, regardless of their navigability, that were 
established by the earliest predecessors to the 1972 Clean Water Act 
and remained in place except during the time period the 2020 NWPR was 
in effect. Interstate waters are, by definition, waters of the 
``several States,'' U.S. Const. Article I, section 8, and are 
unambiguously ``waters of the United States.'' In addition, categorical 
protection of interstate waters is the construction of the Clean Water 
Act that is most consistent with the text of the statute, including 
section 303(a), its purpose and history, Supreme Court case law, and 
the agencies' charge to implement a ``comprehensive regulatory 
program'' that protects the chemical, physical, and biological 
integrity of the nation's waters.
    The agencies interpret interstate waters under this rule to mean 
``all rivers, lakes, and other waters that flow across, or form a part 
of, State boundaries'' based on precursor water protection statutes and 
practice. See 33 U.S.C. 466i(e) (1952) (codifying Pub. L. 80-845 
section 10(e), 62 Stat. 1161 (1948)). Interstate waters thus include 
waters that cross or form a part of State boundaries with other States 
and with other countries (Canada and Mexico). Examples of such waters 
include portions of the Amargosa River, which flows from Nevada into a 
dry playa in Death Valley, California, and the Great Dismal Swamp, a 
wetland which crosses the border between Virginia and North Carolina. 
The Amargosa River is not a traditional navigable water and does not 
otherwise flow to a traditional navigable water or the territorial 
seas, but under the agencies' pre-2015 regulations and the final rule, 
the portion of the Amargosa River that crosses the California/Nevada 
border is an interstate water. Tributaries to interstate waters like 
the Amargosa River and wetlands adjacent to interstate waters and their 
tributaries are critical sources of life in desert climates. Interstate 
waters also include waters that meet the definition of a traditional 
navigable water or are tributaries of traditional navigable waters or 
the territorial seas, such as the portions of the Ohio River and 
Mississippi River that cross or serve as State boundaries; the portions 
of the Rio Grande that cross State boundaries (Colorado/New Mexico) or 
that cross the border or serve as the border between the United States 
and Mexico; and Lake Champlain, which crosses the New York/Vermont 
border and crosses the border between the United States and Canada.
    Because, as explained below, the Clean Water Act unambiguously 
includes interstate waters, they are fundamental to the Act in the same 
manner as traditional navigable waters and the territorial seas. Even 
if the text of the Clean Water Act does not unambiguously resolve the 
question of jurisdiction over interstate waters, the agencies have 
concluded that it is reasonable to construe the statute to protect 
interstate waters without need for further assessment based on the 
history of the statute, Supreme Court case law interpreting the Act, 
the legislative history, and the objective of the Act to restore and 
maintain the integrity of the nation's waters. Therefore, this rule, 
like the 1986 regulations, provides Clean Water Act protections for 
interstate waters in the same manner as for traditional navigable 
waters and the territorial seas, and the following waters that meet the 
relatively permanent standard or significant nexus standard based on 
their connection to interstate waters are ``waters of the United 
States'': tributaries to interstate waters, wetlands adjacent to 
interstate waters or to their jurisdictional tributaries, and paragraph 
(a)(5) waters.
    Interstate waters may be streams, lakes or ponds, or wetlands. The 
longstanding definition of ``waters of the United States'' includes 
interstate wetlands. As discussed in section IV.A.2.b.ii of this 
preamble, the Clean Water Act's statutory text, structure, and history 
establish that adjacent wetlands are ``waters of the United States'' 
covered by the Act. And, while the Supreme Court's focus in Riverside 
Bayview was on adjacent wetlands, the Court's unanimous conclusion that 
section 404(g)(1) provides express textual evidence ``that the term 
`waters' included adjacent wetlands,'' 474 U.S at 138, is informative 
for interstate wetlands as well. For more than 45 years the agencies 
have concluded that waters, for purposes of the Clean Water Act, 
include wetlands. The agencies have also, for more than 45 years, 
concluded that some of those wetlands are ``waters of the United 
States,'' and among those wetlands are interstate wetlands. Because the 
agencies consider wetlands to be waters, the rationale for covering 
interstate waters based on the history of the statute, Supreme Court 
case law interpreting the Act, legislative history, and the objective 
of the Act applies with full force to interstate wetlands.

[[Page 3073]]

    Under this provision of the rule, consistent with the pre-2015 
regulatory regime, lakes, ponds, impoundments, and similar lentic (or 
still) water resources, as well as wetlands, crossing State boundaries 
are jurisdictional as interstate waters through the entirety of their 
delineated extent.
    For streams and rivers, the agencies will determine the upstream 
and downstream extent of the stream or river crossing a State boundary 
or serving as a State boundary that should be considered the 
``interstate water'' using stream order. Stream order is a common, 
longstanding scientific concept of assigning whole numbers to indicate 
the branches of a stream network. Under this method, for rivers and 
streams, the ``interstate water'' extends upstream and downstream of 
the State boundary for the entire length that the water is of the same 
stream order. See section IV.C.4.c.ii.1 of this preamble for additional 
information about stream order.
(2) Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    Until 1972, the predecessors of the Clean Water Act explicitly 
protected interstate waters independent of their navigability. The 1948 
Water Pollution Control Act declared that the ``pollution of interstate 
waters'' and their tributaries is ``a public nuisance and subject to 
abatement.'' 33 U.S.C. 466a(d)(1) (1952) (codifying Pub. L. 80-845 
section 2(d)(1), 62 Stat. 1156 (1948)). Interstate waters were defined 
without reference to navigability: ``all rivers, lakes, and other 
waters that flow across, or form a part of, State boundaries.'' 33 
U.S.C. 466i(e) (1952) (codifying Pub. L. 80-845 section 10(e), 62 Stat. 
1161 (1948)).
    In 1961, Congress broadened the 1948 statute and made the pollution 
of ``interstate or navigable waters'' subject to abatement, retaining 
the definition of ``interstate waters.'' 33 U.S.C. 466g(a) (1964) 
(codifying Pub. L. 87-88 section 8(a), 75 Stat. 204, 208 (1961)). In 
1965, Congress required States to develop water quality standards for 
``interstate waters or portions thereof within such State.'' 33 U.S.C. 
1160(c)(1) (1970) (codifying Pub. L. 89-234 section 5, 79 Stat. 903, 
908 (1965)); see also 33 U.S.C. 1173(e) (1970) (retaining definition of 
``interstate waters''). In the 1972 Clean Water Act, Congress abandoned 
the ``abatement'' approach initiated in the 1948 statute in favor of a 
focus on permitting for discharges of pollutants.
    While the term ``navigable waters'' is ambiguous in some respects, 
interstate waters are waters that are clearly covered by the plain 
language of the definition of ``navigable waters.'' Congress defined 
``navigable waters'' to mean ``the waters of the United States, 
including the territorial seas.'' Interstate waters are, by definition, 
waters of the ``several States,'' U.S. Const. section 8, and 
consequently, are unambiguously ``waters of the United States.'' The 
1972 Clean Water Act thus reflects Congress's recognition that the 
degradation of water resources in one State may cause substantial harms 
in other States. The Supreme Court has recognized that ``the power 
conferred by the Commerce Clause [is] broad enough to permit 
congressional regulation of activities causing air or water pollution, 
or other environmental hazards that may have effects in more than one 
State.'' Hodel v. Virginia Surface Mining & Reclamation Ass'n, 452 U.S. 
264, 282 (1981).
    In addition, the text of the 1972 Clean Water Act specifically 
addresses ``interstate waters'' regardless of their navigability. 
Namely, section 303(a) of the 1972 Clean Water Act uses the term 
``interstate waters'' and provides that pre-existing water quality 
standards for ``interstate waters'' remain in effect unless EPA 
determined that they were inconsistent with any applicable requirements 
of the pre-1972 version of the Act. 33 U.S.C. 1313(a)(1). That plain 
language is a clear indication that Congress intended the agencies to 
continue to protect the water quality of interstate waters without 
reference to their navigability. Excluding ``interstate waters'' as an 
independent category of Clean Water Act jurisdiction would disregard 
the plain language of section 303(a).
    The Supreme Court has concluded that the 1972 Clean Water Act was 
``not merely another law `touching interstate waters,''' but rather 
``occupied the field through the establishment of a comprehensive 
regulatory program supervised by an expert administrative agency.'' 
City of Milwaukee v. Illinois, 451 U.S. 304, 317 (1981) (``City of 
Milwaukee''). Thus, the 1972 amendments superseded the Federal common 
law of nuisance as a means to protect interstate waters in favor of a 
statutory ``all-encompassing program of water pollution regulation,'' 
id. at 318, and they did not curtail the scope of protected waters.
    Even if the text and history of the statute and Supreme Court case 
law interpreting the Clean Water Act do not unambiguously resolve the 
issue, the situation addressed by the Supreme Court in the City of 
Milwaukee case highlights the reasonableness of the agencies' 
interpretation that the Act protects interstate waters. The City of 
Milwaukee litigation involved alleged discharges of inadequately 
treated sewage from Milwaukee, Wisconsin sewer systems directly into 
Lake Michigan, which also borders Illinois. As the Supreme Court noted, 
prior to passage of the Clean Water Act, these discharges would have 
had to be resolved through litigation, in which the courts must apply 
``often vague and indeterminate nuisance concepts and maxims of equity 
jurisprudence.'' Id. at 317. However, the Clean Water Act replaced this 
unpredictable and inefficient approach with ``a comprehensive 
regulatory program supervised by an expert administrative agency.'' Id. 
The Court reiterated that view in Arkansas v. Oklahoma, stating in the 
context of an NPDES permit for a discharge of pollutants to interstate 
waters that, while the Clean Water Act may place some limits on 
downstream States' participation in the permitting process, those 
limits ``do not in any way constrain the EPA's authority to require a 
point source to comply with downstream water quality standards.'' 503 
U.S. 91, 106 (1992) (emphasis in original).
    The potential for interstate harm, and the consequent need for 
Federal regulation, is particularly clear with respect to waterbodies 
that span more than one State. The alternative interpretation would 
leave interstate waters that do not fall within any other provisions in 
the definition of ``waters of the United States'' without Federal 
protection. Parties in different States would need to resolve concerns 
about upstream discharges in non-jurisdictional waters through 
litigation using ``often vague and indeterminate nuisance concepts and 
maxims of equity jurisprudence.'' City of Milwaukee, 451 U.S. at 317; 
see also 85 FR 22286 (April 21, 2020) (acknowledging in the 2020 NWPR 
that ``remedies for pollution disputes among States that do not 
implicate CWA sections 319(g), 401, or 402 would likely derive from 
federal common law under the Supreme Court's original jurisdiction. 
Remedies for disputes between a State and a public or private party 
would likely derive from State or federal common law and be heard by 
State or Federal courts'' (citations omitted)). Restoration of 
longstanding protections for interstate waters, regardless of whether 
they are navigable-in-fact, enables the agencies to address interstate 
water quality issues efficiently and effectively. The agencies 
interpret interstate waters to encompass all waters that Congress has 
sought to protect since 1948: all rivers, lakes, and

[[Page 3074]]

other waters that flow across, or form a part of, State boundaries. 
Public Law 80-845, sec. 10, 62 Stat. 55, at 1161 (1948). These waters 
need not meet the relatively permanent standard or significant nexus 
standard to be jurisdictional under the final rule.
    EPA has interpreted the Clean Water Act to cover interstate waters, 
with the exception of the 2020 NWPR, since 1973. 38 FR 13528 (May 22, 
1973) (providing that the term ``waters of the United States'' includes 
``interstate waters and their tributaries, including adjacent 
wetlands''). In the final rule promulgated in 1977, the Corps adopted 
EPA's definition and included ``interstate waters and their 
tributaries, including adjacent wetlands'' within the definition of 
``waters of the United States.'' The preamble to that rule provided an 
explanation for the inclusion of interstate waters: ``The affects [sic] 
of water pollution in one state can adversely affect the quality of the 
waters in another, particularly if the waters involved are interstate. 
Prior to the FWPCA amendments of 1972, most federal statutes pertaining 
to water quality were limited to interstate waters. We have, therefore, 
included this third category consistent with the Federal government's 
traditional role to protect these waters from the standpoint of water 
quality and the obvious effects on interstate commerce that will occur 
through pollution of interstate waters and their tributaries.'' 42 FR 
37122, 37127 (July 19, 1977).
    Because the Clean Water Act unambiguously includes interstate 
waters, they are fundamental to the Act in the same manner that 
traditional navigable waters and the territorial seas are. Traditional 
navigable waters, the territorial seas, and interstate waters cannot be 
protected without also protecting the waters that have a significant 
nexus to those waters. This rule protects interstate waters in the same 
manner as it protects traditional navigable waters and the territorial 
seas. Thus, the following waters that meet the relatively permanent 
standard or significant nexus standard based on their connection to 
interstate waters are ``waters of the United States'': tributaries to 
interstate waters, wetlands adjacent to interstate waters or to their 
jurisdictional tributaries, and paragraph (a)(5) waters. The agencies 
received multiple comments on the proposed rule in favor of the 
categorical inclusion of interstate waters as ``waters of the United 
States,'' as well as multiple comments arguing that categorical 
inclusion of interstate waters is inconsistent with the Clean Water 
Act. Several commenters asserted that asserting categorical 
jurisdiction over interstate waters is legally permissible, with some 
arguing that the statutory language unambiguously demonstrates that the 
Clean Water Act protects all interstate waters. One commenter stated 
that the agencies' failure to protect all interstate waters in the 2020 
NWPR ``was an abdication of a core premise of the Clean Water Act's 
cooperative federalism.'' One commenter added that Federal jurisdiction 
over interstate waters protects State sovereignty, rather than 
threatening it, and quoted Justice Scalia's plurality opinion in 
Rapanos that ``the Act protects downstream States from out-of-state 
pollution that they cannot themselves regulate.'' 547 U.S. at 777. 
Several of the commenters discussed downstream pollution to demonstrate 
their general support for including interstate waters as a 
jurisdictional category. Many of these commenters added that including 
interstate waters in the definition of ``waters of the United States'' 
helps reduce the burden of increased pollutants from out-of-state, 
upstream discharges.
    Commenters opposed to the categorical inclusion of interstate 
waters stated that such an approach unlawfully reads the notion of 
navigability out of the Clean Water Act. A few commenters asserted that 
pursuant to SWANCC, Riverside Bayview, and Rapanos, interstate waters 
or interstate wetlands can only be jurisdictional if they are navigable 
or connected to navigable waters. In support of their arguments, some 
commenters cited the 2020 NWPR and the order of the U.S. District Court 
for the Southern District of Georgia remanding the 2015 Clean Water 
Rule. Georgia v. Wheeler, 418 F. Supp. 3d 1336, 1358-59 (S.D. Ga. 2019) 
(concluding that the categorical inclusion of interstate waters exceeds 
the agencies' statutory authority because it ``reads the term 
navigability out of the CWA''). For the reasons articulated above, the 
agencies conclude that the interpretation of the agencies' authority 
over interstate waters articulated in the 2020 NWPR and in Georgia v. 
Wheeler is inconsistent with both the text and the history of the Clean 
Water Act, as well as Supreme Court case law.
    A few commenters disagreed with the agencies' proposal to determine 
jurisdiction over tributaries to interstate waters, wetlands adjacent 
to interstate waters or their jurisdictional tributaries, and paragraph 
(a)(5) waters, by applying the relatively permanent or significant 
nexus standards to analyze their connection to the interstate water. 
Alternatively, a few commenters supported interstate waters being 
treated like traditional navigable waters and the territorial seas for 
purposes of determining the jurisdictional status of tributaries to 
interstate waters, wetlands adjacent to interstate waters or their 
jurisdictional tributaries, and paragraph (a)(5) waters. The agencies 
have concluded that, since interstate waters are clearly jurisdictional 
under the statute, the statute requires the same protections for them 
as the Clean Water Act does for traditional navigable waters and the 
territorial seas. As the scientific support for protecting tributaries, 
adjacent wetlands, and paragraph (a)(5) waters that satisfy the 
relatively permanent or significant nexus standard is the same for 
interstate waters as it is for traditional navigable waters and the 
territorial seas, the agencies have reasonably defined ``waters of the 
United States'' to protect such tributaries, adjacent wetlands, and 
paragraph (a)(5) waters.
    In the proposed rulemaking, the agencies requested comment on 
approaches for implementing the interstate waters provision, including 
approaches for determining the upstream and downstream extent of a 
stream or river crossing a State boundary or serving as a State 
boundary that should be considered the ``interstate water.'' Several 
commenters stated that the entire length of a waterbody that is of the 
same stream order as the point that crosses State lines should be 
considered an interstate water, and therefore jurisdictional. These 
commenters added that where a river or stream itself forms the 
boundary, the entire length of stream forming the boundary should be 
considered an interstate water, and therefore jurisdictional. These 
commenters also added that any additional reach of the stream that is 
the same stream order as the portion forming the boundary should also 
be jurisdictional. One commenter stated that this stream order approach 
is well-understood and consistent with the longstanding pre-2015 
regulatory regime and stated that it is also consistent with 
longstanding accepted scientific practice. Alternatively, a few 
commenters voiced opposition or concern for using stream order to 
determine the reach of an interstate water, with one commenter stating 
that the approach is restrictive and another stating that it could be 
too expansive. The agencies agree with commenters who stated that 
stream order is an appropriate approach for determining the upstream 
and downstream limits of an interstate water that is a stream or river. 
The agencies conclude that this

[[Page 3075]]

approach is reasonable and provides a method that is transparent, well-
understood, predictable, and easy to implement. This approach is 
consistent with longstanding practice under the pre-2015 regulatory 
regime and thus is familiar to the agencies and the public. 
Additionally, this method is consistent with the agencies' approach to 
characterizing tributary reaches based on stream order for purposes of 
applying the relatively permanent standard in this rule (see section 
IV.C.4.c.ii of this preamble), and the agencies' approach to 
characterizing tributary reaches based on stream order to delineate the 
catchment for purposes of applying the significant nexus standard in 
this rule (see section IV.C.4.c.iii of this preamble).
(3) Waters That Cross a State-Tribal Bundary
    The agencies requested comment in the proposed rule on whether 
interstate waters should encompass waters that flow across, or form a 
part of, boundaries of federally recognized Tribes where these waters 
simultaneously flow across, or form a part of, State boundaries. See 
Public Law 80-845, sec. 10, 62 Stat. 1155, at 1161 (1948). The agencies 
also sought comment on how to identify ``Tribal boundaries'' for 
purposes of implementing the interstate waters provision, such as 
boundaries associated with a Tribe's reservation or boundaries 
associated with the term ``Indian country'' as defined at 18 U.S.C. 
1151.
    Multiple commenters expressed support for treating waters that 
cross or serve as State/Tribal boundaries as interstate waters, with 
some commenters stating that waters that cross or serve as boundaries 
between the lands of different Tribes (i.e., Tribal/Tribal boundaries) 
should also be deemed interstate waters under the rule. Other 
commenters did not support treating waters that cross or serve as 
State/Tribal boundaries as interstate waters. Some commenters provided 
input on which boundary should be considered a Tribal boundary for 
purposes of the interstate waters category, with many of those 
commenters expressing a preference for using ``Indian country'' as 
defined at 18 U.S.C. 1151 to delineate Tribal boundaries. A few 
commenters suggested that a category broader than ``Indian country'' 
should be used to adequately reflect Tribal interests and rights.
    As evidenced by the feedback the agencies have received, the issue 
of how to address ``Tribal boundaries'' for purposes of implementing 
the interstate waters provision is of great importance to Tribes as 
well as various stakeholders. The agencies recognize the range of views 
expressed on this issue to date, including support for interpreting 
Tribal boundaries to include all waters that flow across, or form a 
part of, Indian country boundaries; support for finding that interstate 
waters include waters outside of Indian country that flow into areas 
where Tribes exercise treaty or other rights; opposition to interstate 
waters generally including waters that flow across, or form part of, 
Tribal boundaries; and views in between. The agencies also acknowledge 
commenters who raised questions regarding implementation of potential 
interpretations of interstate waters as applied to Tribal boundaries.
    The agencies have considered the input received during pre-proposal 
Tribal consultation and the public comment period for the proposed rule 
and, at this time, are continuing to evaluate the issue of interstate 
waters and Tribal boundaries, including what should appropriately be 
considered ``Tribal boundaries'' for purposes of identifying interstate 
waters under the Clean Water Act. The agencies have weighed the 
benefits of addressing this issue now, based on the record currently 
before them, versus undertaking additional analysis and outreach to 
Tribes to gain a better understanding of Tribal boundaries as related 
to interstate waters and related implications via a separate process, 
described below, to avoid delaying the entire rule.
    Based on the agencies' evaluation of the comments received and the 
benefits of further analysis and outreach, the agencies have decided to 
conduct additional analysis and outreach to inform a future action 
related to considering designating waters that cross a State/Tribal 
boundary as interstate waters under the definition of ``waters of the 
United States.'' The agencies recognize the importance of this issue to 
Tribes and are fully committed to directly engaging with Tribal 
governments as the agencies continue to evaluate this aspect of the 
scope of ``waters of the United States.''
    Accordingly, the agencies will address this issue in a subsequent 
action after completing additional analysis and essential outreach and 
engagement activities with Tribes and interested stakeholders. Although 
the agencies are not taking a position on this specific issue at this 
time, a water that crosses a State/Tribal boundary may be 
jurisdictional if it otherwise falls within this rule's definition of 
``waters of the United States.''
3. Impoundments
a. This Rule
    Consistent with the proposal, this rule retains the provision in 
the 1986 regulations that defines ``waters of the United States'' to 
include impoundments of ``waters of the United States.'' Impoundments 
are distinguishable from natural lakes and ponds because they are 
created by discrete structures (often human-built) like dams or levees 
that typically have the effect of raising the water surface elevation, 
creating or expanding the area of open water, or both. Impoundments can 
be natural (like beaver ponds) or artificial (like reservoirs).
    The agencies' implementation of the paragraph (a)(2) impoundments 
category \91\ is based on two primary principles. First, as a matter of 
policy, law, and science, impoundments do not render ``waters of the 
United States'' no longer ``waters of the United States.'' Second, as a 
matter of policy and science, if an impounded water has the 
characteristics of another jurisdictional water, then the impoundment 
is jurisdictional. Based on these principles, in implementing this rule 
the agencies consider paragraph (a)(2) impoundments to include (1) 
impoundments created by impounding one of the ``waters of United 
States'' that was jurisdictional under this rule's definition at the 
time the impoundment was created, and (2) impoundments of waters that 
at the time of assessment meet the definition of ``waters of the United 
States'' under paragraph (a)(1), (a)(3), or (a)(4) of this rule, 
regardless of the water's jurisdictional status at the time the 
impoundment was created. Waters that are jurisdictional under paragraph 
(a)(5) are the exception to these two implementing principles. The text 
of this regulation states that they are not covered by paragraph 
(a)(2). Therefore, waters that are jurisdictional under paragraph 
(a)(5) do not categorically retain their jurisdictional status as 
``waters of the United States''

[[Page 3076]]

under paragraph (a)(2).\92\ However, a subsequently impounded 
jurisdictional paragraph (a)(5) water may still be determined to be 
jurisdictional if it meets the requirements of a category of ``waters 
of the United States'' other than paragraph (a)(2) at the time of 
assessment (i.e., as a traditional navigable water, the territorial 
seas, an interstate water, a jurisdictional tributary, a jurisdictional 
adjacent wetland, or a paragraph (a)(5) water).\93\
---------------------------------------------------------------------------

    \91\ Impounded waters may be jurisdictional under provisions 
other than the paragraph (a)(2) impoundments provision. For example, 
they may be impoundments that are traditional navigable waters and 
would be jurisdictional under paragraph (a)(1), or they may be 
impounded adjacent wetlands and meet the requirements to be 
jurisdictional under the paragraph (a)(4) adjacent wetlands 
provision. To provide clarity in this preamble, when the agencies 
are discussing the subsection of impoundments that are 
jurisdictional under paragraph (a)(2) because they are impoundments 
of ``waters of the United States,'' the agencies will refer to 
``paragraph (a)(2) impoundments.''
    \92\ When an approved jurisdictional determination does not 
exist for an impounded water that the agencies conclude based on its 
characteristics could only be jurisdictional under paragraph (a)(5), 
the paragraph (a)(2) impoundments provision does not apply and the 
water will be assessed under another jurisdictional category.
    \93\ For example, if a stream that is not part of the tributary 
system of a paragraph (a)(1) water, but which is assessed under 
paragraph (a)(5) and is determined to meet the significant nexus 
standard, is lawfully impounded subsequent to the jurisdictional 
determination, the stream is not automatically jurisdictional as a 
paragraph (a)(2) water under this rule. However, the impounded 
stream may still meet the significant nexus standard under paragraph 
(a)(5) or the impounded stream may develop the characteristics of a 
traditional navigable water and become jurisdictional under 
paragraph (a)(1).
---------------------------------------------------------------------------

    Consistent with the 1986 regulations, under this rule tributaries 
may be tributaries to paragraph (a)(1) or (a)(2) waters. Tributaries to 
paragraph (a)(2) impoundments, and wetlands adjacent to such 
tributaries, are jurisdictional if they meet either the relatively 
permanent standard or the significant nexus standard. Additionally, 
wetlands adjacent to paragraph (a)(2) impoundments are jurisdictional 
if they meet either the relatively permanent standard or the 
significant nexus standard. In order for a tributary to a paragraph 
(a)(2) impoundment to meet the relatively permanent standard, the 
agencies must be able to trace evidence of a flowpath (e.g., physical 
features on the landscape, such as a channel, ditch, pipe, or swale) 
directly or indirectly through another water or waters, downstream from 
the structure that creates the paragraph (a)(2) impoundment to a 
paragraph (a)(1) water. When evaluating a wetland adjacent to a 
paragraph (a)(2) impoundment under the relatively permanent standard, 
field staff would assess whether the impounded water is relatively 
permanent, standing or continuously flowing, and then determine whether 
the wetland has a continuous surface connection to the impoundment. 
When evaluating a wetland adjacent to a jurisdictional tributary to a 
paragraph (a)(2) impoundment when the jurisdictional tributary meets 
the relatively permanent standard, field staff would determine whether 
the wetland has a continuous surface connection to the tributary. See 
section IV.C.4.c and section IV.C.5.c of this preamble for additional 
information on evaluations under the relatively permanent standard for 
tributaries and adjacent wetlands. For a tributary to a paragraph 
(a)(2) impoundment, a wetland adjacent to a paragraph (a)(2) 
impoundment, or a wetland adjacent to a tributary to a paragraph (a)(2) 
impoundment, that is assessed under the significant nexus standard, the 
significant nexus must be to a paragraph (a)(1) water. See sections 
IV.C.4.c and IV.C.5.c of this preamble for additional information on 
significant nexus evaluations for tributaries and adjacent wetlands.
b. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    The agencies have determined that as a matter of law, science, and 
policy, impoundments do not de-federalize a water, and therefore 
impoundments of ``waters of the United States'' remain ``waters of the 
United States.'' The Supreme Court has confirmed that damming or 
impounding ``waters of the United States'' does not make those waters 
non-jurisdictional. See S.D. Warren Co. v. Maine Bd. of Envtl. Prot., 
547 U.S. 370, 379 n.5 (2006) (``S.D. Warren'') (``[N]or can we agree 
that one can denationalize national waters by exerting private control 
over them.''). While S.D. Warren addressed the meaning of the word 
``discharge'' rather than the definition of ``waters of the United 
States,'' the Court's conclusion regarding the jurisdictional status of 
a dammed river supports the agencies' longstanding interpretation of 
the Clean Water Act that ``waters of the United States'' remain 
``waters of the United States'' even if impounded, as reflected in the 
1986 regulations and continued in this rule. Essentially, the action of 
creating an impoundment cannot on its own render ``waters of the United 
States'' no longer jurisdictional.\94\ The Court of Appeals for the 
Ninth Circuit has similarly found that ``it is doubtful that a mere 
man-made diversion would have turned what was part of the waters of the 
United States into something else and, thus, eliminated it from 
national concern.'' United States v. Moses, 496 F.3d 984, 988 (9th Cir. 
2007), cert. denied, 554 U.S. 918 (2008).
---------------------------------------------------------------------------

    \94\ Note that a Clean Water Act section 404 permit may 
authorize impoundment of a water such that the water is no longer 
jurisdictional, for example, to create a waste treatment system that 
is excluded from the definition of ``waters of the United States.'' 
In such circumstances, the water is analyzed under the regulatory 
exclusion where applicable, not under the impoundments provision of 
the definition.
---------------------------------------------------------------------------

    Asserting Clean Water Act jurisdiction over impoundments also 
aligns with the scientific literature, as well as the agencies' 
scientific and technical expertise and experience, which confirm that 
impoundments have chemical, physical, and biological effects on 
downstream waters through surface or subsurface hydrologic connections. 
As discussed in section III.C of the Technical Support Document, 
impoundments are typically built to maintain some level of hydrologic 
connection between the water that is being impounded and the downstream 
tributary network. For example, water may pass from a reservoir to the 
downstream side of an impoundment by passing through a main spillway or 
outlet works, passing over an auxiliary spillway, or overtopping the 
impoundment. Indeed, berms, dikes, and similar features used to create 
impoundments typically do not block all water flow. Even dams, which 
are specifically designed and constructed to impound large amounts of 
water effectively and safely, generally do not prevent all water flow, 
but rather allow seepage under the foundation of the dam and through 
the dam itself. See, e.g., International Atomic Energy Agency, 2003, 
``Investigating Leaks in Dams & Reservoirs.'' INIS-XA-616. Vienna, 
Austria (``All dams are designed to lose some water through 
seepage.''); U.S. Bureau of Reclamation, ``Safety of Dams.'' Provo Area 
Office (last updated July 1, 2017) (``All dams seep, but the key is to 
control the seepage through properly designed and constructed filters 
and drains.''); Federal Energy Regulatory Commission, 2005, ``Chapter 
14: Dam Safety Performance Monitoring Program.'' Engineering Guidelines 
for the Evaluation of Hydropower Projects. (``Seepage through a dam or 
through the foundations or abutments of dams is a normal condition.''). 
Further, as an agency with expertise and responsibilities in 
engineering and public works, the Corps extensively studies water 
retention structures like berms, levees, and earth and rock-fill dams. 
The agency has found that all water retention structures are subject to 
seepage through their foundations and abutments. See section III.C of 
the Technical Support Document.
    Paragraph (a)(2) waters include impoundments created in waters that 
were jurisdictional under this rule's definition at the time the 
impoundment was created, as well as impoundments of waters that at the 
time of assessment are jurisdictional under paragraph (a)(1), (a)(3), 
or (a)(4) of this rule regardless of

[[Page 3077]]

the water's jurisdictional status at the time the impoundment was 
created.\95\ This is generally consistent with the agencies' 
longstanding approach to impoundments. See U.S. Army Corps of Engineers 
Jurisdictional Determination Form Instructional Guidebook (2007) at 58, 
available at https://www.usace.army.mil/Missions/Civil-Works/Regulatory-Program-and-Permits/Related-Resources/CWA-Guidance/ 
(hereinafter, ``2007 Corps Instructional Guidebook''). The agencies 
have concluded that it is appropriate based on relevant case law, 
science, and as a practical matter to interpret ``waters of the United 
States'' to include both impoundments of waters that qualified as 
``waters of the United States'' under this rule's definition at the 
time of impoundment, and impoundments of waters that at the time of 
assessment meet the definition of ``waters of the United States'' 
(other than waters jurisdictional under paragraph (a)(5)). As discussed 
above, waters that qualified as ``waters of the United States'' at the 
time of impoundment (other than waters jurisdictional under paragraph 
(a)(5)) remain ``waters of the United States.'' And impoundments of 
waters that at the time of assessment fall within one of the other 
categories of ``waters of the United States'' in this rule (other than 
waters jurisdictional under paragraph (a)(5)) are jurisdictional under 
paragraph (a)(2).
---------------------------------------------------------------------------

    \95\ See infra for a discussion of impoundments of waters that 
are jurisdictional as paragraph (a)(5) waters, which are treated 
differently under this rule.
---------------------------------------------------------------------------

    The agencies received a variety of comments on impoundments during 
the public comment period. Some commenters supported the agencies' 
inclusion of impoundments of ``waters of the United States'' as a 
separate category of jurisdictional waters. A few commenters stated 
that the relatively permanent standard and significant nexus standard 
should also apply to impoundments for the purposes of jurisdiction. 
Some commenters agreed with the proposed rule's approach to not include 
impounded paragraph (a)(5) waters in the impoundments category. Many 
commenters requested the agencies provide greater clarity about the 
definition of impoundments.
    After consideration of public comments and for the reasons 
described above and in section III.C of the Technical Support Document, 
the agencies affirm in this rule that impoundments of ``waters of the 
United States'' remain ``waters of the United States,'' except for 
impoundments of paragraph (a)(5) waters, which the agencies find are 
better assessed under other categories of this rule. As discussed 
above, paragraph (a)(2) impoundments of ``waters of the United States'' 
legally remain ``waters of the United States,'' so the agencies are not 
requiring an additional determination of their jurisdiction under this 
rule. While the agencies are not defining ``impoundment'' in this rule, 
in this preamble the agencies are providing additional clarity below 
about the types of impoundments that are and that are not considered 
``waters of the United States'' under paragraph (a)(2). Additionally, 
section IV.C.3.c of this preamble provides implementation guidance for 
identifying impoundments on the landscape.
    As in the proposed rule, impoundments of waters that are determined 
to be jurisdictional under paragraph (a)(5) are not included in this 
rule as paragraph (a)(2) impoundments. As discussed above, impoundments 
of paragraph (a)(5) waters would need to be assessed for jurisdiction 
in their current state under paragraph (a)(1), (a)(3), (a)(4), or 
(a)(5) of this rule. Thus, if a water is determined to be 
jurisdictional under paragraph (a)(5) and is then later lawfully 
impounded, it is not jurisdictional by rule under the paragraph (a)(2) 
impoundments provision. Instead, the impoundment of a paragraph (a)(5) 
water would itself need to be assessed in its current state to 
determine whether it is jurisdictional under one of the provisions of 
the rule besides paragraph (a)(2). Impounded paragraph (a)(5) waters 
will most likely continue to not meet any of the other categories of 
jurisdictional waters and will therefore need to be re-assessed under 
paragraph (a)(5). However, if, once impounded, such a water became, for 
example, a traditional navigable water, it would be jurisdictional 
under paragraph (a)(1) of this rule. This approach in this rule is 
consistent with the agencies' careful approach to jurisdiction over 
paragraph (a)(5) waters. For example, as discussed in sections IV.C.4 
and IV.C.5 of this preamble below, the ``tributaries'' category does 
not include tributaries to paragraph (a)(5) waters and the adjacent 
wetlands category does not include wetlands adjacent to paragraph 
(a)(5) waters. This change from the 1986 regulations reflects the 
agencies' consideration of the jurisdictional concerns and limitations 
of the statute as informed by SWANCC and Rapanos.
c. Implementation
    Under this rule, for the reasons discussed above, impounding a 
water that meets the definition of ``waters of the United States'' 
generally does not affect such water's jurisdictional status, 
consistent with pre-2015 practice. See 2007 Corps Instructional 
Guidebook at 58. A water can be found to be a jurisdictional 
impoundment under paragraph (a)(2) of this rule if (1) the impounded 
water met the definition of ``waters of the United States'' based on 
this rule's definition at the time the impoundment was created \96\ 
(other than an impoundment of a paragraph (a)(5) water) or (2) the 
water that is being impounded, at the time of assessment, meets the 
definition of ``waters of the United States'' under paragraph (a)(1), 
(a)(3), or (a)(4), regardless of the water's jurisdictional status when 
the impoundment was created. The agencies also note that over time an 
impoundment of a water that does not initially meet the definition of 
``waters of the United States'' can become jurisdictional under another 
provision of the regulation; for example, an impounded water could 
become navigable-in-fact and covered under paragraph (a)(1)(i) of this 
rule. This approach to implementation of impoundments is generally 
consistent with pre-2015 practice. This section of the preamble 
provides information for determining jurisdiction for impoundments 
under paragraph (a)(2) and for determining jurisdiction for tributaries 
of impoundments, wetlands adjacent to impoundments, and wetlands 
adjacent to tributaries of impoundments.
---------------------------------------------------------------------------

    \96\ Note, however, if an impoundment is a waste treatment 
system constructed prior to the 1972 Clean Water Act amendments, it 
is eligible for the exclusion under paragraph (b) of this rule so 
long as the system is in compliance with currently applicable Clean 
Water Act requirements, such as treating water such that discharges, 
if any, from the system meet the Act's requirements. See section 
IV.C.7.b of this preamble.
---------------------------------------------------------------------------

i. Determining the Presence of a Paragraph (a)(2) Impoundment
    Impoundments are distinguishable from natural lakes and ponds 
because they are created by discrete structures (often human-built) 
like dams or levees that typically have the effect of raising the water 
surface elevation, creating or expanding the area of open water, or 
both. Impoundments can vary in size, with some being very small and 
others being very large, like Lake Mead, a reservoir on the Colorado 
River that is created by the Hoover Dam. Paragraph (a)(2) impoundments 
under this rule can include both natural impoundments (like beaver 
ponds) and artificial impoundments (like reservoirs). Paragraph (a)(2) 
impoundments under this rule can be located off-channel (i.e.,

[[Page 3078]]

an impoundment with no outlet or hydrologic connection to the tributary 
network) or in-line with the channel (i.e., an impoundment with a 
hydrologic connection to the tributary network).
    An impoundment is jurisdictional under paragraph (a)(2) of this 
rule if the impounded water met the definition of ``waters of the 
United States'' based on this rule's definition when the impoundment 
was created (other than impoundments of paragraph (a)(5) waters). To 
determine if an impoundment meets this criterion, the water would be 
assessed to see if the water was jurisdictional as a paragraph (a)(1) 
water, tributary, or adjacent wetland based on this rule's definition 
at the time it was impounded. Tools that can be used for such 
assessment are discussed further in sections IV.C.4.c and IV.C.5.c of 
this preamble. Historic aerial photographs, maps, and geospatial 
datasets may be particularly useful in helping to determine if a water 
was jurisdictional under paragraph (a)(1), (a)(3), or (a)(4) of this 
rule at the time the impoundment was created, especially where such 
materials depict the aquatic system before and after the impoundment 
was created. Similarly, planning, engineering, and design documents, if 
available, may provide useful information.
    Paragraph (a)(2) waters also include impoundments of waters that at 
the time of assessment are jurisdictional under paragraph (a)(1), 
(a)(3), or (a)(4) of this rule regardless of the water's jurisdictional 
status at the time the impoundment was created. This approach is 
consistent with pre-2015 practice. See 2007 Corps Instructional 
Guidebook at 58. A water that is impounded may not meet this rule's 
jurisdictional criteria at the time the water was originally impounded, 
but the water may meet this rule's jurisdictional criteria at the time 
of the assessment (in some cases, many years later). This is because 
aquatic resources generally can evolve over time as aquatic landscapes, 
precipitation and other climatic patterns, and other environmental 
conditions change, or due to human-caused changes (e.g., stream 
modification, filling in of wetlands, water withdrawals, or effluent 
discharges). Impounded waters may be particularly likely to evolve as 
the surface waters are raised or expanded behind the impoundment. To 
determine if an impoundment is jurisdictional based on such changes, 
the impounded water would be assessed to see if it is a traditional 
navigable water, the territorial seas, an interstate water, a 
jurisdictional tributary, or a jurisdictional adjacent wetland. Tools 
that can be used for such assessment are discussed further in sections 
IV.C.4.c and IV.C.5.c of this preamble.
    In assessing if an impoundment of a paragraph (a)(1) water is 
jurisdictional under paragraph (a)(2), the agencies would assess 
whether the water that is being impounded met the requirements to be a 
paragraph (a)(1) water under this rule either at the time of 
impoundment or at the time of assessment. Impoundments of paragraph 
(a)(1) waters that continue to meet the requirements under paragraph 
(a)(1) remain paragraph (a)(1) waters.
    In assessing whether an impoundment of a tributary is 
jurisdictional under paragraph (a)(2), the agencies would first assess 
if the tributary either met this rule's definition of ``waters of the 
United States'' at the time the impoundment was created or if the 
tributary meets this rule's definition of ``waters of the United 
States'' at the time of assessment. For impoundments of tributaries 
that met this rule's definition of ``waters of the United States'' at 
the time the impoundment was created, the agencies must be able to 
demonstrate that at the time the impoundment was created, there was 
evidence of a flowpath (e.g., physical features on the landscape, such 
as a channel, ditch, pipe, or swale) directly or indirectly through 
another water or waters, downstream from the structure that created the 
impoundment to a paragraph (a)(1) water. Thus, an impoundment of a 
tributary that met this rule's definition of ``waters of the United 
States'' at the time the impoundment was created could currently be 
located off-channel (e.g., due to changes in hydrology) or in-line with 
the channel, but the flowpath would only need to be traceable at the 
time the impoundment was created. For impoundments of tributaries that 
meet this rule's definition of ``waters of the United States'' at the 
time of assessment, the agencies must be able to at the time of 
assessment trace a flowpath directly or indirectly through another 
water or waters, downstream from the structure that creates the 
impoundment to a paragraph (a)(1) water. Thus, impoundments of 
tributaries that meet the definition of ``waters of the United States'' 
at the time of assessment will always be in-line with the channel due 
to the flowpath requirement. This is consistent with the agencies' 
approach to tributaries under the final rule. See section IV.C.4. of 
this preamble. As with assessment of tributaries under this rule, while 
the physical flowpath from the paragraph (a)(2) impoundment to the 
paragraph (a)(1) water must be traceable, there is not a need to 
demonstrate that flow from the impoundment reaches the paragraph (a)(1) 
water. For an off-channel impoundment (i.e., an impoundment with no 
outlet to the tributary network), such as an impoundment of a 
jurisdictional adjacent wetland, such a flowpath is not required. Under 
the final rule, adjacent wetlands do not require a flowpath to the 
tributary network, and similarly, impoundments of such adjacent 
wetlands do not require a flowpath. The agencies would only need to 
determine that the impoundment was created in a water that is currently 
jurisdictional under paragraphs (a)(1) through (4) or that the 
impoundment was created in a water that was jurisdictional under 
paragraphs (a)(1) through (4) at the time the impoundment was created.
    In assessing whether an impoundment of an adjacent wetland is 
jurisdictional under paragraph (a)(2), the agencies would need to 
determine that the impoundment was created in an adjacent wetland that 
was jurisdictional at the time the impoundment was created or that is 
currently jurisdictional at the time of assessment. Such impoundments 
of adjacent wetlands may be located either off-channel or in-line with 
the channel, and do not require a traceable flowpath that is required 
for impoundments of tributaries. This is because under the final rule, 
adjacent wetlands do not require a flowpath to the tributary network, 
and similarly, impoundments of such adjacent wetlands do not require a 
flowpath.
    Because impoundments can be jurisdictional under other categories 
of ``waters of the United States'' under this rule, field staff may 
document that the impoundment is jurisdictional under other categories. 
For example, if an impoundment is itself a traditional navigable water, 
part of the territorial seas, or an interstate water, the agencies 
would typically determine that the impoundment is a paragraph (a)(1) 
water, rather than asserting jurisdiction under paragraph (a)(2) of 
this rule. Field staff may document any such waters as jurisdictional 
under the relevant provision of the rule rather than documenting that 
it is jurisdictional as a paragraph (a)(2) impoundment.
    Finally, as discussed above in section IV.C.3.b of this preamble, 
waters that are jurisdictional under paragraph (a)(5) and that are 
subsequently impounded do not categorically retain their jurisdictional 
status as ``waters of the United States'' under paragraph (a)(2). If 
the impoundment of the paragraph (a)(5) water does not meet the 
jurisdictional standards under one of

[[Page 3079]]

the other categories of ``waters of the United States'' in this rule 
(i.e., as a paragraph (a)(1) water, jurisdictional tributary, or 
jurisdictional adjacent wetland), the impoundment would be re-assessed 
as a paragraph (a)(5) water. Implementation of waters assessed under 
paragraph (a)(5) is discussed in section IV.C.6.c of this preamble.
ii. Determining Jurisdiction for Tributaries of Impoundments, Wetlands 
Adjacent to Impoundments, and Wetlands Adjacent to Tributaries of 
Impoundments
    Tributaries of paragraph (a)(2) impoundments are jurisdictional, as 
with all tributaries under this rule, when they meet either the 
relatively permanent standard or the significant nexus standard. In 
order to determine if a water is a tributary of a paragraph (a)(2) 
impoundment, the same tools and methods can be used that are discussed 
in section IV.C.4.c.i of this preamble to trace the flowpath to the 
impoundment. Field staff would then determine if the tributary should 
be evaluated under the relatively permanent standard or the significant 
nexus standard. For tributaries assessed under the relatively permanent 
standard, the agencies must be able to trace evidence of a flowpath 
downstream from the structure that creates the impoundment to a 
paragraph (a)(1) water. To meet the latter standard, the significant 
nexus must be to a paragraph (a)(1) water. Implementation of the 
relatively permanent standard for tributaries is discussed in more 
detail in section IV.C.4.c.ii of this preamble. Implementation of the 
significant nexus standard for tributaries is discussed in section 
IV.C.4.c.iii of this preamble.
    For tributaries of paragraph (a)(2) impoundments that are evaluated 
under the relatively permanent standard, field staff would determine if 
the tributary has flowing or standing water year-round or continuously 
during certain times of the year, see section IV.C.4.c.ii of this 
preamble, and then determine whether there is evidence of a flowpath 
downstream from the structure that creates the impoundment to a 
paragraph (a)(1) water. As with all tributaries under the rule, there 
is no requirement under the relatively permanent standard for 
relatively permanent flow for the entirety of a tributary's flowpath to 
a downstream paragraph (a)(1) water. See id. Thus, under the relatively 
permanent standard for tributaries of paragraph (a)(2) impoundments, 
field staff would not need to determine that flow occurs over, through, 
around, or underneath the structure that creates the impoundment. 
Instead, the agencies will document that flow occurs from the tributary 
to the impoundment, either directly or indirectly through another water 
or waters, including non-jurisdictional features, as described in 
section IV.C.4 of this preamble, and that there is evidence of a 
flowpath downstream of the structure (e.g., physical features on the 
landscape, such as a channel, non-jurisdictional ditch, pipe, or swale) 
to a paragraph (a)(1) water, either directly or indirectly through 
another water or waters. For example, a tributary may flow through 
another stream that flows infrequently, and only in direct response to 
precipitation, and the presence of that stream is sufficient to 
demonstrate that the tributary flows to a paragraph (a)(1) water.
    If a wetland is adjacent to a paragraph (a)(2) impoundment and that 
wetland is evaluated under the relatively permanent standard, field 
staff would, only for purposes of determining whether the adjacent 
wetland meets the relatively permanent standard, assess whether the 
impounded water is relatively permanent, standing or continuously 
flowing. Next, field staff would determine whether the wetland has a 
continuous surface connection to the paragraph (a)(2) impoundment, 
consistent with section IV.C.5 of this preamble. If the paragraph 
(a)(2) impoundment is not relatively permanent, standing or 
continuously flowing, then field staff will assess the adjacent wetland 
under the significant nexus standard.
    If a wetland is adjacent to a tributary to a paragraph (a)(2) 
impoundment, and the tributary meets the relatively permanent standard, 
the wetland would be assessed for whether it has a continuous surface 
connection to the tributary, consistent with section IV.C.5 of this 
preamble. If the adjacent wetland does not have a continuous surface 
connection, it will be assessed under the significant nexus standard. 
If the tributary does not meet the relatively permanent standard, then 
field staff will assess the adjacent wetland under the significant 
nexus standard. To apply the significant nexus standard to tributaries 
of paragraph (a)(2) impoundments, wetlands adjacent to those 
tributaries, or wetlands adjacent to paragraph (a)(2) impoundments, the 
agencies will assess if the waters of interest significantly affect the 
chemical, physical, or biological integrity of paragraph (a)(1) waters 
using the tools and approaches described in sections IV.C.4.c.iii and 
IV.C.5.c.iii of this preamble. As part of that analysis, the agencies 
will determine if there is a surface or subsurface hydrologic 
connection downstream that is maintained over, through, around, or 
underneath the structure that creates the impoundment. Such a 
hydrologic connection can occur in a variety of ways, such as 
overtopping of the structure or through features like dam spillways, 
drainage and other galleries, sluiceways, culverts, pipes, diversion 
tunnels, or conduits that are built to maintain a hydrologic connection 
through the dam or levee. Subsurface hydrologic connectivity can also 
occur via seepage through or underneath the dam or similar structure. 
Field staff can document that surface or subsurface hydrologic 
connectivity occurs using direct observation of overtopping or a 
feature that is constructed to maintain a hydrologic connection, 
through review of construction plans for the structure, through other 
field observations (e.g., dye tests or tracer studies, or observations 
of flow within the spillway such as bent over vegetation or water 
staining where the spillway is concrete, soil saturation, changes in 
vegetation above and below the structure), or through remote tools 
(e.g., aerial photography interpretation that provides indications of 
wetter signatures below the dam). As stated in section IV.C.9 of this 
preamble, a hydrologic connection to a paragraph (a)(1) water is not 
necessary to determine that the water being evaluated significantly 
affects the integrity of paragraph (a)(1) waters, though it is one of 
the factors that is considered. Where such a hydrologic connection 
exists at the surface or subsurface, it can help to facilitate the 
functions that the tributary of the paragraph (a)(2) impoundment 
performs that impact the downstream paragraph (a)(1) water, such as 
contribution of flow, pollutants, sediment, and organic material. In 
the rare circumstances where such a hydrologic connection does not 
exist, the lack of such a connection can facilitate other functions, 
such as holding back floodwaters that could otherwise harm paragraph 
(a)(1) waters. See preamble section IV.C.9 for additional information 
on implementing the significant nexus standard more generally.
4. Tributaries
a. This Rule
    Consistent with the proposal, this rule retains the tributary 
provision of the 1986 regulations, updated to reflect consideration of 
the law, the science, and agency expertise. The 1986 regulations 
defined ``waters of the United States'' to include tributaries of 
traditional navigable waters, interstate waters, paragraph (a)(3) 
``other waters''

[[Page 3080]]

(a category that has been modified and codified in this rule as 
paragraph (a)(5) waters) and impoundments. With this rule, the agencies 
are adding the territorial seas to the list of waters to which 
tributaries may connect to constitute a jurisdictional tributary and 
removing paragraph (a)(3) waters from the list. This rule defines 
``waters of the United States'' to include tributaries of traditional 
navigable waters, the territorial seas, interstate waters, or paragraph 
(a)(2) impoundments if the tributaries meet either the relatively 
permanent standard or the significant nexus standard.
    The 1986 regulations do not contain a definition of ``tributary,'' 
and the agencies similarly are not including a definition in this rule. 
However, for more than 45 years, the agencies have recognized the need 
to protect ``the many tributary streams that feed into the tidal and 
commercially navigable waters . . . since the destruction and/or 
degradation of the physical, chemical, and biological integrity of each 
of these waters is threatened by the unregulated discharge of dredged 
or fill material.'' 42 FR 37121, 37123 (July 19, 1977). Accordingly, 
the agencies are maintaining their interpretation of tributary for 
purposes of the definition of ``waters of the United States.'' See 
Rapanos Guidance at 6 n.24. A tributary for purposes of this rule 
includes rivers, streams, lakes, ponds, and impoundments, regardless of 
their flow regime, that flow directly or indirectly through another 
water or waters to a traditional navigable water, the territorial seas, 
or an interstate water. Waters through which a tributary may flow 
indirectly include, for example, impoundments, wetlands, lakes, ponds, 
and streams. A tributary may flow through a number of downstream 
waters, including a non-jurisdictional tributary or non-jurisdictional 
features, such as a ditch excluded under paragraph (b) of this rule or 
an excluded waste treatment system, and jurisdictional waters that are 
not tributaries, such as an adjacent wetland. But to be jurisdictional, 
the tributary must be part of a tributary system that eventually flows 
to a traditional navigable water, the territorial seas, or an 
interstate water. The agencies will utilize the Corps' well-established 
definition of an ordinary high water mark (OHWM) to assist in 
identifying tributaries for purposes of this rule. See section 
IV.C.4.c.i of this preamble for information on using the OHWM to assist 
in identifying a water as a tributary for purposes of this rule. To be 
a jurisdictional tributary under this provision of the rule, the 
tributary must meet either the relatively permanent standard or the 
significant nexus standard.
    Like the 1986 regulations, this rule includes tributaries of 
interstate waters since interstate waters, like traditional navigable 
waters and the territorial seas, are waters clearly protected by the 
Clean Water Act. In this rule, the agencies are adding the territorial 
seas to the list of waters to which tributaries may connect to 
constitute a jurisdictional tributary because the territorial seas are 
explicitly protected by the Clean Water Act. Because the territorial 
seas are explicitly covered by the Clean Water Act, it is reasonable 
and appropriate to protect tributaries to the territorial seas that 
meet either the relatively permanent standard or the significant nexus 
standard for the same reasons that tributaries to traditional navigable 
waters are protected. In practice, the agencies recognize that most 
tributaries will reach a traditional navigable water before they reach 
the territorial seas. Finally, consistent with the 1986 regulations, 
this rule includes tributaries that flow directly or indirectly through 
another water or waters to paragraph (a)(2) impoundments.\97\
---------------------------------------------------------------------------

    \97\ See discussion of tributaries to paragraph (a)(2) 
impoundments in section IV.C.3 of this preamble.
---------------------------------------------------------------------------

    The agencies' longstanding interpretation of the Clean Water Act 
includes tributaries that are natural, modified, or constructed waters. 
The Clean Water Act, in defining ``navigable waters,'' does not turn on 
any such distinctions, which have no bearing on a tributary's capacity 
to carry water (and pollutants) to paragraph (a)(1) waters. See, e.g., 
Technical Support Document section II.B.iv.3 (explaining that human-
made ditches ``perform many of the same functions as natural 
tributaries,'' including ``convey[ing] water that carries nutrients, 
pollutants, and other constituents, both good and bad, to downstream 
traditional navigable waters''). Given the extensive human modification 
of watercourses and hydrologic systems throughout the country, it is 
often difficult to distinguish, as a practical or scientific matter, 
between natural watercourses and watercourses that are wholly or partly 
modified or constructed. For example, tributaries that have been 
channelized in concrete or otherwise have been modified would still be 
tributaries for purposes of this rule so long as they contribute flow 
to a traditional navigable water, the territorial seas, or an 
interstate water, and so long as they are not excluded under paragraph 
(b) of this rule. Thus, tributaries can include ditches and canals.
    Under this rule, swales and erosional features (e.g., gullies, 
small washes) characterized by low volume, infrequent, or short 
duration flow are not tributaries and are not jurisdictional. See 
section IV.C.7 of this preamble.
    Once a water is determined to be a tributary, under this rule, the 
tributary must meet either the relatively permanent or significant 
nexus standard to be jurisdictional. The relatively permanent standard 
encompasses tributaries that have flowing or standing water year-round 
or continuously during certain times of the year. Relatively permanent 
waters do not include tributaries with flowing or standing water for 
only a short duration in direct response to precipitation. In 
evaluating tributaries under the significant nexus standard, the 
agencies will determine whether the tributaries, either alone or in 
combination with similarly situated waters in the region, significantly 
affect the chemical, physical, or biological integrity of paragraph 
(a)(1) waters. Implementation of each of those standards for purposes 
of determining jurisdiction over tributaries is discussed below in 
section IV.C.4.c of this preamble.
b. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    Commenters expressed a range of views on the agencies' proposed 
treatment of tributaries. This section of the preamble provides a 
summary of the major comments received on the regulatory text and the 
agencies' consideration of the comments. The preamble to the proposed 
rule also provided information about the agencies' longstanding 
interpretation of practice for identifying tributaries for purposes of 
the definition of ``waters of the United States,'' and this section 
also summarizes and addresses major comments received on those topics.
i. Comments on the Tributaries Provision of This Rule
    Some commenters requested that the agencies include a definition of 
``tributary'' in this rule. A subset of these commenters stated that 
the definition should include waters with a bed, bank, or other 
evidence of flow that contribute flow directly or indirectly to 
downstream paragraph (a)(1) waters. Other commenters maintained that 
the lack of a formal definition makes it unclear which features are 
tributaries and which are not. Some of these commenters stated that the 
lack of a

[[Page 3081]]

definition left too much discretion to the agencies to identify 
tributaries based on physical features, which they asserted would lead 
to confusion. Some commenters supported the proposed approach for 
assessing tributaries, stating that the longstanding interpretation and 
practice would allow for regionalized implementation. Although the 
agencies are not promulgating a new definition of ``tributary'' the 
agencies have decades of experience implementing the 1986 regulations 
(which also did not include a definition of ``tributary'') and have 
concluded that a new regulatory definition of tributary is not 
required. To provide further clarity, the agencies have been careful in 
this preamble to articulate and explain the agencies' well-established 
interpretation and practices for identifying tributaries. In addition, 
the agencies note that while the first step under this provision of the 
regulation is to identify whether a water is a tributary under 
longstanding practice, that is not the end of the inquiry under this 
rule, in contrast to the 1986 regulations. A water must not only be a 
tributary but must also meet either the relatively permanent standard 
or the significant nexus standard to be jurisdictional under this 
provision. These standards provide important limitations that also help 
define the scope of the tributaries that are jurisdictional under the 
rule.
    Commenters on the proposed rule expressed a variety of perspectives 
on the appropriate scope of jurisdiction for tributaries. Some 
commenters supported the proposal that tributaries are jurisdictional 
if they meet either the relatively permanent or significant nexus 
standard. Other commenters asserted that tributaries should meet both 
standards. Some commenters stated that this rule should include 
categorical protections for all tributaries (e.g., features with an 
OHWM), rather than requiring case-by-case analysis, asserting that such 
an interpretation is supported by the science and Supreme Court case 
law. For the reasons described in section IV.A of this preamble, this 
rule defines ``waters of the United States'' to include tributaries 
that meet either the relatively permanent standard or the significant 
nexus standard on a case-specific basis.
    Some commenters criticized the definition of ``tributary'' from the 
2020 NWPR, while others supported that definition, stating that it was 
clear and logical. The 2020 NWPR defined ``tributary'' as a river, 
stream, or similar naturally occurring surface water channel that 
contributes surface water flow to the territorial seas or a traditional 
navigable water in a typical year either directly or indirectly through 
other tributaries, jurisdictional lakes, ponds, or impoundments, or 
adjacent wetlands. A tributary was required to be perennial or 
intermittent in a typical year. 85 FR 22251 (April 21, 2020). The 
definition of ``tributary'' in the 2020 NWPR failed to advance the 
objective of the Clean Water Act and was inconsistent with scientific 
information about the important effects of many types of tributaries on 
the integrity of downstream paragraph (a)(1) waters.
    The key limitations that the 2020 NWPR created in its definition of 
``tributary,'' which this rule does not adopt, are the categorical 
exclusion of ephemeral streams and the requirement that streams 
contribute flow to a traditional navigable water or territorial sea in 
a ``typical year.'' With respect to ephemeral streams, commenters 
provided a wide variety of perspectives on whether they should be 
jurisdictional under this rule. Some commenters asserted that the 
agencies' interpretation of tributary should exclude ephemeral streams. 
Some commenters asserted that ephemeral streams should be categorically 
jurisdictional under this rule. These commenters referenced the 
importance of ephemeral streams for providing functions like nutrient 
and materials transport, erosion and flood control, water quality 
maintenance downstream, drinking water and irrigation provisioning, 
groundwater recharge, and wildlife habitat. Other commenters asserted 
that ephemeral streams are important for buffering against the impacts 
of climate change, supporting Tribal communities, and providing 
functions in specific regions like arid areas. Another group of 
commenters stated that all ephemeral streams should be non-
jurisdictional across the country, or non-jurisdictional in certain 
regions such as the arid West. These commenters asserted that ephemeral 
streams do not flow frequently enough or provide sufficiently important 
functions to impact the integrity of downstream paragraph (a)(1) 
waters. As discussed further in section IV.A of this preamble, the 
agencies are not categorically including or excluding streams as 
jurisdictional based on their flow regime in this rule. The agencies 
agree that ephemeral streams can provide many important functions for 
paragraph (a)(1) waters.
    With respect to the ``typical year requirement'' in the 2020 NWPR 
definition of ``tributary,'' the agencies found it challenging and 
sometimes impossible to implement, for the reasons discussed in section 
IV.B.3.c of this preamble. The ``typical year'' requirement for 
tributaries was also not supported by science. Scientific information 
does not demonstrate that only those streams that contribute 
intermittent or perennial flow to a traditional navigable water or 
territorial sea in a ``typical year'' have significant effects on the 
chemical, physical, and biological integrity of larger downstream 
waters, including paragraph (a)(1) waters. See sections IV.B.3.a and 
IV.B.3.b of this preamble. Because the limitations in the 2020 NWPR's 
definition of ``tributary'' are inconsistent with science and created 
substantial implementation difficulties, the agencies are not adopting 
this definition. See section III.A of the Technical Support Document 
for more information on the agencies' rationale for the scope of 
tributaries covered by this rule. Streams that are tributaries, 
regardless of their flow regime, will be assessed under the relatively 
permanent or significant nexus standard per paragraph (a)(3) of this 
rule, and streams that are not tributaries will be assessed under the 
relatively permanent or significant nexus standard per paragraph (a)(5) 
of this rule.
    Some commenters opposed as arbitrary and unsupported by the law or 
science the agencies' proposed approach to delete the category for 
intrastate lakes and ponds, streams, or wetlands that do not meet 
another jurisdictional category (the (a)(3) ``other waters'' provision 
from the 1986 regulations) as a category of waters to which tributaries 
may connect to be determined ``waters of the United States.'' Some of 
these commenters requested clarification as to how tributaries to 
intrastate lakes and ponds, streams, or wetlands that do not meet 
another jurisdictional category would be assessed. One commenter 
asserted that the agencies were ``excluding'' tributaries to paragraph 
(a)(5) waters. Streams that flow to paragraph (a)(5) waters are not 
excluded in this rule. Deleting the cross reference to the category for 
intrastate lakes and ponds, streams, or wetlands that do not meet 
another jurisdictional category (the (a)(3) ``other waters'' provision 
from the 1986 regulations) as a category of waters to which tributaries 
may connect reflects the agencies' consideration of the statute as a 
whole and the jurisdictional concerns and limitations of SWANCC and 
Rapanos. The agencies have concluded that a provision that authorizes 
consideration of jurisdiction over tributaries that meet the relatively 
permanent or significant nexus standard when assessed based simply on 
connections to such waters would have

[[Page 3082]]

too tenuous a connection to paragraph (a)(1) waters. However, in this 
rule any such streams that flow to jurisdictional paragraph (a)(5) 
waters could be assessed themselves under the paragraph (a)(5) waters 
category to determine if they meet the relatively permanent or 
significant nexus standard. For example, a stream that flows to a lake 
that meets the significant nexus standard under the paragraph (a)(5) 
waters provision could itself be assessed under the paragraph (a)(5) 
waters provision to determine whether it significantly affects the 
chemical, physical, or biological integrity of a paragraph (a)(1) 
water.
ii. Comments on the Interpretation and Implementation of the 
Tributaries Provision of This Rule
    As discussed further above, the agencies interpret tributary for 
purposes of this rule to include rivers, streams, lakes, ponds, and 
impoundments that flow directly or indirectly through another water or 
waters to a traditional navigable water, the territorial seas, an 
interstate water, or a paragraph (a)(2) impoundment. The agencies 
received comments on elements of this longstanding interpretation of 
tributary for purposes of the ``waters of the United States.''
    Some commenters disagreed with the agencies' interpretation that 
tributaries include certain lakes and ponds. Some of these commenters 
stated that lakes and ponds should comprise a separate jurisdictional 
category. Several commenters asserted that considering certain lakes 
and ponds to be tributaries could lead to overly broad jurisdiction, 
and one commenter requested clarification in this rule that not every 
feature that might be considered a lake or a pond is necessarily 
jurisdictional. Other commenters agreed with the agencies' longstanding 
approach. Lakes, ponds, and impoundments function as part of the 
tributary system where they contribute flow to downstream waters, and 
therefore it is reasonable to assess them for jurisdiction as 
tributaries under this rule. The agencies will continue to interpret 
the regulations to address lakes, ponds, and impoundments with both an 
inlet and outlet connected to the tributary network, as well as lakes, 
ponds, and impoundments with an outlet connected to the tributary 
network as tributaries if they contribute flow directly or indirectly 
through one or more waters or features that lie along the flowpath to a 
paragraph (a)(1) water. The agencies have extensive experience 
implementing this approach under pre-2015 practice. The agencies 
disagree that this approach will lead to overly broad jurisdiction, as 
these lakes, ponds, and impoundments that are tributaries must meet 
either the relatively permanent standard or significant nexus standard 
to be jurisdictional. Therefore, not every lake, pond, or impoundment 
is jurisdictional as a tributary or under other provisions of this 
rule.
    Some commenters supported the agencies' longstanding interpretation 
that tributaries include waterbodies that flow ``directly or 
indirectly'' to a paragraph (a)(1) water, while other commenters 
asserted that tributaries must flow ``directly'' into a paragraph 
(a)(1) water. There is no text in the Clean Water Act supporting this 
limitation, and the agencies have never interpreted the Act to cover 
only such tributaries. Even the Rapanos plurality opinion did not so 
limit the scope of tributaries covered by the Act. 547 U.S. at 742. 
Moreover, the science is clear that the chemical, physical, and 
biological integrity of paragraph (a)(1) waters depends on the many 
tributaries, including headwater streams, that feed such waters. It 
would be impossible to restore and maintain the chemical, physical, and 
biological integrity as required by the Clean Water Act with a 
definition of ``waters of the United States'' that included solely the 
last tributary that flows ``directly'' into a paragraph (a)(1) water. 
Tributaries upstream provide key functions that support the chemical, 
physical, and biological integrity of paragraph (a)(1) waters. If 
protections for tributaries ended just above the very last one, 
functions like habitat for salmon spawning, baseflow to maintain water 
levels, and nutrient replenishment would all be at risk. See Technical 
Support Document sections I.A and III.E.ii.
    A tributary may contribute flow through a number of downstream 
waters or features, including both non-jurisdictional features, such as 
a ditch excluded under paragraph (b) of this rule, and jurisdictional 
waters that are not tributaries, such as an adjacent wetland. However, 
the tributary must be part of a system that eventually flows to a 
paragraph (a)(1) water. Waters that are part of a system that never 
reaches a paragraph (a)(1) water, for example, a small system of 
streams that ultimately flow to a non-navigable stream in an intrastate 
basin with no outlet, are not jurisdictional under this provision of 
this rule.
    Some commenters asserted that the agencies' approach to 
interpreting ``tributary'' would potentially allow the agencies to 
include wetlands as tributaries. The agencies disagree. While wetlands 
may be a water through which a tributary flows directly or indirectly 
to a paragraph (a)(1) water, the agencies do not consider that wetland 
to be a tributary itself. This is consistent with pre-2015 practice. 
Only when a wetland lies entirely below the OHWM, will it be identified 
as part of the tributary consistent with current practice; even then, 
the wetland is not identified as a tributary itself. Otherwise, such 
wetlands are considered adjacent wetlands and will be evaluated under 
paragraph (a)(4) of this final rule.
    Some commenters supported the agencies' longstanding interpretation 
that there is no meaningful distinction among natural, human-altered, 
or human-made tributaries in terms of their functions, values, and 
influence on the integrity of downstream waters. Some commenters 
requested clarification as to whether both human-made and natural 
tributaries would be regulated in this rule. Some commenters asserted 
that the agencies' proposed approach to interpreting ``tributary'' is 
overly broad and expansive because it would potentially allow the 
agencies to include ditches and human-made conveyances as tributaries. 
The agencies disagree with commenters who asserted that the agencies' 
approach to human-made tributaries is overly broad and expansive. The 
approach is consistent with the agencies' decades-long practice and the 
scientific record, and such tributaries must still meet either the 
relatively permanent standard or the significant nexus standard to be 
jurisdictional under this rule. As noted above, given the extensive 
human modification of watercourses and hydrologic systems throughout 
the country, it is often difficult to distinguish between natural 
watercourses and watercourses that are wholly or partly human-made or 
human-altered. Because natural, human-altered, and human-made 
tributaries provide many of the same functions, especially as conduits 
for the movement of water and pollutants to other tributaries or 
directly to paragraph (a)(1) waters, the agencies have interpreted the 
1986 regulations to cover such tributaries. Ditches, for example, are 
tributaries under this rule if they flow directly or indirectly to 
paragraph (a)(1) waters and they are jurisdictional tributaries if they 
also meet the relatively permanent standard or significant nexus 
standard and are not excluded from jurisdiction under this rule. See 
section IV.C.7 of this preamble for additional discussion on excluded 
ditches.

[[Page 3083]]

c. Implementation
    A tributary for purposes of this rule includes rivers, streams, 
lakes, ponds, and impoundments that flow directly or indirectly through 
another water or waters to a traditional navigable water, the 
territorial seas, an interstate water, or a paragraph (a)(2) 
impoundment. A tributary may flow through a number of downstream 
waters, including non-jurisdictional features. This section of the 
preamble provides additional information on the agencies' 
interpretation and implementation of the tributary provision of this 
rule. This section first explains how to determine whether a water is a 
tributary for purposes of this rule. The section next explains how to 
determine whether a tributary is jurisdictional under the relatively 
permanent standard or under the significant nexus standard.
i. Determining Whether a Water Is a Tributary for Purposes of This Rule
    This section describes how to (1) identify a tributary for purposes 
of this rule and (2) determine whether the tributary is part of the 
tributary system of a traditional navigable water, the territorial 
seas, an interstate water, or a paragraph (a)(2) impoundment.
(1) Identifying a Water as a Tributary
    In implementing this rule, the agencies are maintaining their 
longstanding interpretation that tributaries for purposes of Clean 
Water Act jurisdiction include rivers, streams, lakes, ponds, and 
impoundments. See 2007 Corps Instructional Guidebook at 8, 9. As 
discussed above, although tributaries are required to flow directly or 
indirectly through another water or waters to certain downstream 
waters, tributaries are not required to have a specific flow regime to 
meet the agencies' interpretation of ``tributary.'' However, flow 
characteristics like duration and timing of flow will be considered in 
determining whether tributaries meet the relatively permanent or 
significant nexus standard, as described further below in sections 
IV.C.4.c.ii and IV.C.4.c.iii of this preamble. Lakes, ponds, and 
impoundments may be at the headwaters of the tributary network (e.g., a 
lake with only an outlet to the tributary network) or farther 
downstream from the headwaters (e.g., a lake with both an inlet and 
outlet connected to the tributary network). Even though such waters are 
considered to be lentic or ``still'' systems, such waters still 
contribute flow downstream at the point that they outlet to the 
tributary network and therefore the agencies have long concluded it is 
appropriate to consider such waters to be tributaries.
    As discussed above in this section of the preamble, the agencies' 
longstanding interpretation of ``tributary'' for purposes of the 
definition of ``waters of the United States'' includes natural, human-
altered, or human-made waterbodies that flow directly or indirectly 
through another water or waters to a traditional navigable water, the 
territorial seas, or an interstate water. See Rapanos Guidance at 6.
    The agencies will utilize the Corps' well-established definition of 
an ordinary high water mark (OHWM) to assist in identifying tributaries 
for purposes of this rule. See section IV.C.8 of this preamble (adding 
the definition of OHWM to EPA's regulation). Tributaries typically have 
at least one indicator of an OHWM and, consistent with pre-2015 
practice, physical OHWM characteristics are used to identify 
waterbodies including streams, lakes, ponds, and ditches that are 
present on the landscape. See, e.g., ``Final Notice of Issuance and 
Modification of Nationwide Permits,'' 65 FR 12818, 12823-24 (March 9, 
2000); 2007 Corps Instructional Guidebook; RGL 05-05 (December 7, 
2005). The OHWM, a term unchanged since 1977, defines the lateral 
limits of jurisdiction in non-tidal ``waters of the United States,'' 
provided the limits of jurisdiction are not extended by adjacent 
wetlands. See 42 FR 37144 (July 19, 1977); 33 CFR 323.3(c) (1978). The 
regulations at 33 CFR 328.3(e) and 329.11(a)(1) list the factors to be 
applied. RGL 05-05 further explains these regulations. Delineation of 
an OHWM in tributaries relies on the identification and interpretation 
of physical features, including topographic breaks in slope, changes in 
vegetation characteristics (e.g., destruction of terrestrial vegetation 
and change in plant community), and changes in sediment characteristics 
(e.g., sediment sorting and deposition). Field indicators, remote 
sensing, and mapping information can also help identify an OHWM. The 
Corps continues to improve regulatory practices across the country 
through ongoing research and the development of regional and national 
OHWM delineation procedures, as described further in section IV.A.ii of 
the Technical Support Document. For example, the Corps has developed 
field indicators to help field staff identify the OHWM in common stream 
types in the arid West. Consistent with longstanding practice, the 
agencies will apply the regulations and use RGL 05-05 and applicable 
OHWM delineation manuals, as well as take other steps as needed to 
ensure that the OHWM identification factors are applied consistently 
nationwide. See Rapanos Guidance at 10-11 n.36.
    The agencies will assess any discontinuity in the OHWM and, 
consistent with pre-2015 practice, a natural or human-made 
discontinuity in the OHWM does not necessarily sever jurisdiction 
upstream. A discontinuity may exist where the stream temporarily flows 
underground. Tributaries may temporarily flow underground in regions 
with karst geology or lava tubes, for example, maintaining similar flow 
characteristics underground and at the downstream point where they 
return to the surface. The agencies will also continue their familiar 
practice that a discontinuity in the OHWM also does not typically sever 
jurisdiction upstream where the OHWM has been removed by development, 
agriculture, or other land uses. For example, tributaries can be 
relocated below ground to allow reasonable development to occur. In 
urban areas, surface waters are often rerouted through an artificial 
tunnel system to facilitate development. See, e.g., Science Report at 
3-3, and sections III.A and IV.A.ii of the Technical Support Document. 
Underground streams are distinct from groundwater due to their very 
direct hydrologic connection to the portions of the tributaries that 
are or re-surface above ground. Typically, groundwater connections 
would be much slower than connections via underground streams. 
Tributaries that have been rerouted underground are contained within a 
tunnel system or other similar channelized subsurface feature, while 
naturally occurring subterranean streams flow within natural conduits 
like karst formations or lava tubes. The agencies will look for 
indicators of flow both above and below the discontinuity. For example, 
a discontinuity in the OHWM may exist due to constructed breaks (e.g., 
culverts, pipes, or dams) \98\ or natural breaks (e.g., debris piles or 
boulder fields). Site specific conditions will continue to determine 
the distance up the tributary network that is evaluated to see if the 
feature creates a temporary break or if it severs the upstream 
connection and constitutes the start of the tributary system.
---------------------------------------------------------------------------

    \98\ Under past practice, the agencies have sometimes 
characterized bridges as artificial breaks, such as under the 2015 
Clean Water Rule. See 80 FR 37106 (June 29, 2015). However, bridges 
do not necessarily create discontinuity in the OHWM, and the 
agencies recognize that tributaries flowing under bridges may still 
show evidence of an OHWM and in such circumstances would continue to 
be jurisdictional where they meet either the relatively permanent or 
significant nexus standard.

---------------------------------------------------------------------------

[[Page 3084]]

    Under this rule, swales and erosional features (e.g., gullies, 
small washes) characterized by low volume, infrequent, or short 
duration flow are not tributaries and are not jurisdictional. See 
section IV.C.7 of this preamble. Because swales and erosional features 
were considered to be generally non-jurisdictional features under pre-
2015 practice, the agencies have extensive experience differentiating 
between these features and tributaries on the landscape. See Rapanos 
Guidance at 11-12. Streams are waterbodies that are typically 
characterized by the presence of a channel and an OHWM, and lakes and 
ponds are waterbodies that are also typically characterized by the 
presence of an OHWM, in the absence of adjacent wetlands. In contrast, 
erosional features like gullies and rills are typically more deeply 
incised than streams and lack an OHWM. Similarly, swales do not have an 
OHWM and typically lack a more defined channel that a stream exhibits. 
See section IV.C.7 of this preamble and section III.A.v of the 
Technical Support Document for additional discussion on how to 
distinguish between tributaries, erosional features, and swales; see 
section IV.A.ii of the Technical Support Document for additional 
discussion on how to identify tributaries based on an OHWM.
    A variety of field and remote tools can be used to determine 
whether a water is a tributary.\99\ Due to limitations associated with 
some remote tools, field verification for accuracy may be necessary 
(e.g., due to scale or vegetation cover, not all tributaries may be 
visible in satellite imagery and aerial photographs or mapped in the 
NHD). Examples of field indicators will be discussed in more detail 
below.
---------------------------------------------------------------------------

    \99\ Direct observation or various remote sensing resources such 
as USGS stream gage data (available at https://waterdata.usgs.gov/nwis/rt), USGS topographic maps (available at https://www.usgs.gov/the-national-map-data-delivery/topographic-maps), high-resolution 
elevation data and associated derivatives (e.g., slope or curvature 
metrics), Federal Emergency Management Agency (FEMA) flood zone maps 
(available at https://msc.fema.gov/portal/home), NRCS soil maps 
(available at https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx), National Hydrography Dataset (NHD) data, 
National Wetlands Inventory (NWI) data, maps and geospatial datasets 
from Tribal, State, or local governments, and/or aerial or satellite 
imagery can also be used. Tributaries are often observable in aerial 
imagery and high-resolution satellite imagery by their topographic 
expression, characteristic linear and curvilinear patterns, dark 
photographic tones, or the presence of riparian vegetation. USGS 
topographic maps often include different symbols to indicate mapped 
hydrographic features (see ``Topographic Map Symbols,'' available at 
https://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf).
---------------------------------------------------------------------------

(2) Identifying Whether the Water Is Part of the Tributary System of a 
Paragraph (a)(1) Water
    The next step in determining whether a waterbody is a tributary is 
to identify whether the waterbody is part of the tributary system of a 
paragraph (a)(1) water. The tributary must flow directly or indirectly 
through another water or waters to a traditional navigable water, the 
territorial seas, or interstate water. Waters through which a tributary 
may flow indirectly include, for example, impoundments, wetlands, 
lakes, ponds, and streams. A tributary may flow through a number of 
downstream waters, including non-jurisdictional features, such as a 
ditch excluded under paragraph (b) of this rule or an excluded waste 
treatment system, and jurisdictional waters that are not tributaries, 
such as an adjacent wetland. But, the tributary must be part of a 
tributary system that eventually flows to a traditional navigable 
water, the territorial seas, or an interstate water to be 
jurisdictional. A tributary may flow through another stream that flows 
infrequently, and only in direct response to precipitation, and the 
presence of that stream is sufficient to demonstrate that the tributary 
flows to a paragraph (a)(1) water. Tributaries are not required to have 
a surface flowpath all the way down to the paragraph (a)(1) water. For 
example, tributaries can contribute flow through certain natural and 
artificial breaks (including certain non-jurisdictional features), some 
of which may involve subsurface flow as described above in section 
IV.C.4.b of this preamble.
    In evaluating the flowpath from a water feature, the agencies can 
use USGS maps; NWI data; Tribal, State, and local knowledge or maps; 
dye tests, tracers, or other on the ground tests; field observations; 
aerial photography; or other remote sensing information. The agencies 
can also use available models, including models developed by Federal, 
Tribal, State, and local governments, academia, and the regulated 
community.\100\ These tools could be used in conjunction with field 
observations, data, and other desktop tools to evaluate whether a 
tributary flows directly or indirectly to a paragraph (a)(1) water. For 
tributaries to paragraph (a)(2) impoundments, a flowpath to the 
impoundment and to a paragraph (a)(1) water can be identified using 
these same tools.
---------------------------------------------------------------------------

    \100\ One such model includes the USGS StreamStats ``Flow 
(Raindrop) Path'' GIS tool which allows the user to click a point on 
a map, after which a flowpath is drawn to estimate where water may 
flow from that point to the stream network, eventually making its 
way to the ocean if the tributary network allows for it available at 
https://streamstats.usgs.gov/ss/. The StreamStats tool may 
potentially be used to identify the flowpath from the subject waters 
to the downstream paragraph (a)(1) water using the ``Flow (Raindrop) 
Path'' component of the tool.
---------------------------------------------------------------------------

ii. Determining Whether a Tributary Meets the Relatively Permanent 
Standard
    Under this rule, tributaries that meet the relatively permanent 
standard are jurisdictional under the Clean Water Act as ``waters of 
the United States.'' In implementing the relatively permanent standard, 
the agencies draw key concepts from the 2020 NWPR's interpretation, but 
modify that rule's approach to ensure the term can be practically 
implemented. Specifically, under this rule the relatively permanent 
standard encompasses surface waters that have flowing or standing water 
year-round or continuously during certain times of the year. Relatively 
permanent waters do not include surface waters with flowing or standing 
water for only a short duration in direct response to precipitation. 
The approach in this rule would encompass tributaries considered 
relatively permanent under the 2020 NWPR, as well as those considered 
relatively permanent under the Rapanos Guidance, providing continuity 
in approach for the regulated community and other stakeholders. 
Tributaries that do not meet the relatively permanent standard must be 
assessed under the significant nexus standard. See section IV.C.4.c.iii 
of this preamble.
    The agencies' interpretation of relatively permanent tributaries to 
include surface waters that have flowing or standing water year-round 
or continuously during certain times of the year is consistent with the 
Rapanos plurality's interpretation of ``waters of the United States.'' 
The Rapanos plurality interpreted ``waters of the United States'' as 
encompassing ``relatively permanent, standing or continuously flowing 
bodies of water,'' including streams, rivers, oceans, lakes, and other 
bodies of waters that form geographical features. 547 U.S. at 739, 742. 
The plurality noted that its reference to ``relatively permanent'' 
waters did ``not necessarily exclude streams, rivers, or lakes that 
might dry up in extraordinary circumstances, such as drought,'' or 
``seasonal rivers, which contain continuous flow during some months of 
the year but no flow during dry months.'' Id. at 732 n.5 (emphasis in 
original); see also 85 FR 22289 (April 21, 2020) (citing the same 
language from the plurality in support of the 2020 NWPR's 
interpretation of relatively permanent waters).

[[Page 3085]]

    The agencies have decided to implement this approach because it is 
consistent with the Rapanos plurality opinion, it reflects and 
accommodates regional differences in hydrology and water management, 
and it can be implemented using available, easily accessible tools. It 
will therefore be a straightforward approach for the agencies and the 
regulated community to implement. In addition, maintaining an 
interpretation that encompasses the tributaries considered relatively 
permanent under the pre-2015 regulatory regime and the 2020 NWPR 
addresses the many comments from stakeholders emphasizing the need for 
clarity and certainty in the scope of ``waters of the United States.''
    ``Flowing water'' under this rule is meant to encompass not just 
streams and rivers, but also lakes, ponds, and impoundments that are 
part of the tributary system, as such waters outlet to the tributary 
network and contribute flow downstream at the outlet point. In 
addition, ``flowing water'' under this rule is meant to encompass those 
tributaries that are frozen for parts of the year. Such tributaries 
typically have flowing water underneath the frozen surface.
    The phrase ``certain times of the year'' is intended to include 
extended periods of standing or continuously flowing water occurring in 
the same geographic feature year after year, except in times of 
drought. The defining characteristic of relatively permanent waters 
with flowing or standing water continuously during only certain times 
of the year is a temporary lack of surface flow, which may lead to 
isolated pools or dry channels during certain periods of the year. The 
phrase ``direct response to precipitation'' is intended to distinguish 
between episodic periods of flow associated with discrete precipitation 
events versus continuous flow for extended periods of time.
    A number of commenters suggested that the agencies interpret 
relatively permanent tributaries to include those that flow year-round 
or at least seasonally (e.g., typically three months), consistent with 
the approach in the Rapanos Guidance. This rule encompasses tributaries 
that are ``relatively permanent'' under the Rapanos Guidance. However, 
the agencies have decided not to use the term ``seasonal'' from the 
Rapanos Guidance for several reasons. First, the agencies have 
determined that directly describing the scenarios in which waters would 
be ``relatively permanent'' is clearer than using the term 
``seasonal,'' the meaning of which can vary and could be misunderstood 
to establish a specific required flow duration. See section 
IV.C.4.c.ii.1 of this preamble for further discussion of the challenges 
of requiring a specific flow duration. Relatively permanent flow may 
occur seasonally, but the phrase is also intended to encompass 
tributaries in which extended periods of standing or continuously 
flowing water are not linked to naturally recurring annual or seasonal 
cycles. Specifically, relatively permanent waters may include 
tributaries in which flow is driven more by various water management 
regimes and practices, such as tributaries with extensive flow 
alteration (e.g., diversions, bypass channels, water transfers) and 
effluent-dependent streams. For example, in areas of the West where 
water withdrawals or groundwater pumping can substantially modify flow 
characteristics, onset and cessation of streamflow in some tributaries 
may be more closely tied to changes in water use associated with 
irrigation than with seasons of the year. In such flow-altered 
tributaries, streamflow may change abruptly throughout the year due to 
adjustments in facility operations or may vary from year to year due to 
changes in water rights or water management regimes. In addition, 
tributaries that typically flow throughout the spring may run dry in 
years following a drought while storage reservoirs are being refilled. 
When evaluating these types of artificially manipulated regimes, the 
agencies may consider information about the regular manipulation 
schedule and may potentially consider other remote resources or on-site 
information to assess flow frequency.
    Other commenters recommended defining relatively permanent 
tributaries using the 2020 NWPR's terms ``perennial'' and 
``intermittent.'' Relatively permanent tributaries under this rule 
encompass tributaries that were jurisdictional under the 2020 NWPR. 
However, the agencies have decided to explain directly the way that the 
relatively permanent standard should be implemented, rather than 
defining the phrase with these terms. As evidenced by the variety of 
comments proposing definitions for ``perennial'' and ``intermittent,'' 
adding these terms to this rule could cause confusion and uncertainty. 
Moreover, many definitions of intermittent incorporate ``seasonal'' 
flow, a concept that the agencies decided not to employ in this rule 
for the reasons discussed above. Other definitions of ``perennial'' and 
``intermittent'' that commenters suggested would require specific 
sources of flow, which the agencies also decided not to establish in 
this rule because such requirements cannot readily apply to 
hydrologically altered waters, and for the reasons discussed in section 
IV.C.4.c.ii.2 of this preamble.
    While this rule implements the scope of relatively permanent 
tributaries consistent with the approach in the 2020 NWPR, it does not 
retain the 2020 NWPR's requirement that the tributaries contribute 
surface water flow to a paragraph (a)(1) water in a ``typical year.'' 
See 85 FR 22251 (April 21, 2020). The 2020 NWPR defined a ``typical 
year'' as when ``precipitation and other climatic variables are within 
the normal periodic range (e.g., seasonally, annually) for the 
geographic area of the applicable aquatic resource based on a rolling 
thirty-year period.'' As discussed in section IV.B.3 of this preamble 
and section II.B.iv.1 of the Technical Support Document, the typical 
year analysis proved difficult to implement and yielded arbitrary and 
potentially outdated results. Moreover, it is not required by the 
plurality opinion in Rapanos, which simply required a ``connect[ion]'' 
to paragraph (a)(1) waters. See 547 U.S. at 742 (describing a 
```wate[r] of the United States''' as ``i.e., a relatively permanent 
body of water connected to traditional interstate navigable waters''). 
This rule's requirement that jurisdictional tributaries flow directly 
or indirectly to downstream paragraph (a)(1) waters or paragraph (a)(2) 
impoundments implements the plurality's ``connect[ion]'' requirement. 
See also section IV.C.4.b of this preamble.
(1) Duration and Timing of Flow for Relatively Permanent Tributaries
    Many commenters recommended that the agencies establish a 
particular flow duration for relatively permanent waters. Suggestions 
ranged from a minimum of three months to 290 days. The agencies decided 
not to establish a minimum duration because flow duration varies 
extensively by region. Establishing a uniform number equally applicable 
to the deserts in the arid West, the Great Lakes region, and New 
England forests would not be scientifically sound. The agencies instead 
have chosen to establish a more flexible approach to implementing this 
rule that accounts for specific conditions in each region. Moreover, it 
would often be infeasible for the regulated community or agency staff 
to determine whether a stream ordinarily flows or whether a lake 
contains standing water, for example, 12 weeks as opposed to 11 weeks 
per year. Even if this determination was possible, such a bright line 
cutoff would not reflect

[[Page 3086]]

hydrological diversity among different regions and alterations in flow 
characteristics. The agencies' conclusion that a minimum duration is 
not feasible is consistent with the pre-2015 regulatory regime, which 
did not establish a bright line cutoff (though provided three months as 
an example of seasonal flow) and with the approach of the 2020 NWPR. 
See 85 FR 22292 (April 21, 2020) (``The agencies are not providing a 
specific duration (e.g., the number of days, weeks, or months) of 
surface flow that constitutes intermittent flow, as the time period 
that encompasses intermittent flow can vary widely across the country 
based upon climate, hydrology, topography, soils, and other 
conditions.'').
    Many factors, including climate, hydrology, topography, soils, and 
other conditions, may affect the period in which relatively permanent 
flow may occur for those relatively permanent waters that do not have 
continuously flowing or standing water year-round. The factors which 
affect streamflow and flow cessation are climatically and 
geographically specific and therefore the periods during which a 
tributary might have relatively permanent flow vary by region. Non-
relatively permanent tributaries are similarly diverse, and the 
mechanisms which differentiate relatively permanent flow from non-
relatively permanent flow also vary by region.
    For example, in parts of the Southeastern United States, 
precipitation is distributed somewhat uniformly throughout the year, 
but increased evapotranspiration during the growing season can reduce 
surficial ground water levels and reduce or remove surface flows late 
in the growing season (e.g., late summer or early autumn). 
Consequently, certain streams in the Southeast may flow primarily in 
the winter or early spring. Non-relatively permanent tributaries in the 
Southeast may often be characterized by the repeated sequence of 
streamflow, flow cessation, and channel drying throughout the year, 
where the onset of streamflow coincides with distinct rainfall events 
and is driven primarily by storm runoff. Streamflow in these systems 
may persist anywhere from a few hours to days at a time, where the 
cessation of flow is most often associated with termination of overland 
flow, hillslope runoff recession, and the depletion of water in 
saturated soils. Although streamflow in these tributaries may occur 
regularly, off and on, over the duration of a season or longer, they do 
not exhibit continuously flowing water for an extended period at any 
point during the year. In other areas of the United States, snowpack 
melt drives streamflow more than rainfall, and relatively permanent 
flow may therefore coincide with warming temperatures in the spring or 
early summer.
    Many headwater streams in mountainous regions flow through channels 
incised in bedrock with no groundwater interface with the bed of the 
stream. Instead, these streams are often fed primarily by high 
elevation snowpack melt. The same scenario may also exist in Northern 
regions, where flows could be fed almost exclusively through melting 
snowpack absent elevated groundwater tables. In these regions, 
relatively permanent flows coincide with warming temperatures in the 
spring or early summer and may persist well into the summer until there 
are no longer enough inputs to sustain surface water, or later into 
autumn when more permanent sources of meltwater (e.g., glaciers or 
snowfields) begin to freeze. Non-relatively permanent flows in these 
regions may occur in basins with thin layers of snow, where snow melts 
rapidly at the onset of spring thaw, and the snowmelt produced is not 
sufficient to sustain flows for an extended period and into the summer.
    To determine the flow characteristics of a tributary for purposes 
of implementing this rule, the agencies will evaluate the entire reach 
of the tributary that is of the same Strahler \101\ stream order (i.e., 
from the point of confluence, where two lower order streams meet to 
form the tributary, downstream to the point such tributary enters a 
higher order stream; see Technical Support Document section IV.A.ii.1). 
The flow characteristics of lakes, ponds, and impoundments that are 
part of the tributary network will be assessed in conjunction with the 
stream they connect to. Consistent with the pre-2015 regulatory regime, 
the agencies will assess the flow characteristics of a particular 
tributary at the farthest downstream limit of such tributary (i.e., the 
point the tributary enters a higher order stream). Rapanos Guidance at 
6 n.24. Where data indicate the flow characteristics at the downstream 
limit are not representative of the entire reach of the tributary, the 
flow characteristics that best characterize the entire tributary reach 
will be used.
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    \101\ Strahler, A.N. 1957. ``Quantitative analysis of watershed 
geomorphology.'' American Geophysical Union Transactions 38: 913-
920.
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(2) Source of Flow for Relatively Permanent Tributaries
    Implementation of the relatively permanent standard for tributaries 
in this rule does not require that relatively permanent flow come from 
particular sources. This rule's approach is consistent with the 
plurality opinion in Rapanos, which lays out the relatively permanent 
standard and does not require that relatively permanent waters 
originate from any particular source. See, e.g., 547 U.S. at 739. This 
rule's approach is also science-based, as the source of a tributary's 
flow does not influence its effect on downstream waters, including 
paragraph (a)(1) waters. This rule's approach is similar to the 
familiar approach taken in the Rapanos Guidance and the 2020 NWPR, 
which also did not specify that relatively permanent flow come from 
particular sources.
    Sources of flow in relatively permanent tributaries may include an 
elevated groundwater table that provides baseflow to a channel bed. 
Relatively permanent flow could also result from upstream contributions 
of flow, effluent flow, or snowpack that melts slowly over time in 
certain geographic regions or at high elevations. In addition, in 
certain regions relatively permanent flow could result from a 
concentrated period of back-to-back precipitation events that leads to 
sustained flow through a combination of runoff and upstream 
contributions of flow or an elevated groundwater table that provides 
baseflow to the channel bed. In contrast, non-relatively permanent 
tributaries may flow only during or shortly after individual 
precipitation events (including rainfall or snowfall events). Non-
relatively permanent flow may occur simply because it is raining or has 
very recently rained, or because a recent snow has melted.
    Streamflow that occurs during the monsoon season in certain parts 
of the country (typically June through September in the arid West) may 
be relatively permanent or non-relatively permanent, depending on the 
conditions at the location. Many tributaries in the arid West are 
dominated by coarse, alluvial sediments and exhibit high transmission 
losses, resulting in streams that often dry rapidly following a storm 
event (e.g., within minutes, hours, or days). These streams are not 
relatively permanent under this rule. However, relatively permanent 
flow may occur as a result of multiple back-to-back storm events 
throughout a watershed, during which the combination of runoff and 
upstream contributions of flow is high enough to exceed rates of 
transmission loss for an extended period of time. Relatively permanent 
flow may also follow one or more larger storm events, when

[[Page 3087]]

floodwaters locally recharge the riparian aquifer through bank 
infiltration, which supplies sustained baseflow throughout the monsoon 
season.
    Similar to the 2020 NWPR's approach, the agencies will consider 
tributaries that flow in direct response to ``snowfall'' for only a 
short duration during or shortly after that snowfall event to be non-
relatively permanent waters under this rule. Streams that flow as a 
result of ``snowpack melt'' will be considered relatively permanent 
waters under this rule, where snowpack is defined as ``layers of snow 
that accumulate over extended periods of time in certain geographic 
regions or at high elevation (e.g., in northern climes or mountainous 
regions).'' See 85 FR 22275 (April 21, 2020). Tributaries that receive 
effluent flow that is relatively permanent will also be assessed under 
the relatively permanent standard.
(3) Tools Available To Determine Whether a Tributary Meets the 
Relatively Permanent Standard
    Section IV.C.4.c.i of this preamble discusses how to determine if 
features on the landscape are tributaries. Direct observations and 
various remote tools and resources can be used to identify tributary 
reaches based on stream order, and topographic characteristics can 
assist in determining stream order. USGS topographic map blue line 
symbology and contour line patterns can be used to interpret the 
connectivity and contribution of flow within a river network, as well 
as topography within an evaluation area. Elevation models, including 
those based on light detection and ranging (LIDAR) derived data, may 
also illustrate tributary connectivity and flow patterns, as well as 
topography. In addition, aerial and satellite imagery along with maps 
or geospatial mapping products (e.g., NHD, NWI, soil maps, and Tribal, 
State, or local maps) can be used to help identify tributary reaches 
based on stream order. In addition to remote tools and resources, 
factors identified through field observations can be used to help 
determine the extent of a tributary reach. For example, tributary 
systems can be traversed to identify and characterize the branches of 
the network that contribute flow to a particular evaluation area. 
Certain geographic features (e.g., non-jurisdictional ditches, swales) 
may also be found to contribute to a tributary's surface hydrology.
    Many available resources and tools can assist in determining 
whether tributaries are relatively permanent. For instance, the 
agencies have been working to develop regionalized streamflow duration 
assessment methods (SDAMs, available at https://www.epa.gov/streamflow-duration-assessment), which are rapid field-based assessment methods 
that can be used to classify streamflow duration and assist in 
determining whether tributaries are ``relatively permanent.'' These 
methods rely on physical and/or biological field indicators, such as 
the presence of hydrophytic vegetation and benthic macroinvertebrates, 
that can be collected or observed in a single site visit to determine 
the flow duration of a tributary in a reliable and rapid way. EPA, the 
Corps, and the State of Oregon developed a regionalized SDAM that has 
been validated for use throughout the Pacific Northwest (available at 
http://www.epa.gov/measurements/streamflow-duration-assessment-method-pacific-northwest). EPA and the Corps have also developed a beta SDAM 
for the arid West (available at https://www.epa.gov/streamflow-duration-assessment/beta-streamflow-duration-assessment-method-arid-west) and the Western Mountains (available at https://www.epa.gov/streamflow-duration-assessment/beta-streamflow-duration-assessment-method-western-mountains). EPA and the Corps are working to develop 
additional regionalized SDAMs in other parts of the country. Other 
agencies have developed similar tools that may be useful in 
implementing this rule.\102\ The agencies, co-regulators, and 
stakeholders can use the regionalized field indicators from SDAMs to 
quickly and easily identify tributaries that are relatively permanent 
as interpreted by the agencies under this rule.
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    \102\ E.g., the Streamflow Methodology for Identification of 
Intermittent and Perennial Streams and Their Origins, developed by 
the North Carolina Division of Water Quality, available at https://files.nc.gov/ncdeq/Water%20Quality/Surface%20Water%20Protection/401/Policies_Guides_Manuals/StreamID_v_4point11_Final_sept_01_2010.pdf.
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    Remote or desktop tools can also help the agencies and the public 
better understand streamflow and whether tributaries have continuously 
flowing or standing water year-round or during certain times of the 
year for more than for a short duration in direct response to 
precipitation.\103\ Satellite imagery and aerial photographs showing 
visible water on multiple dates can provide evidence as to whether 
tributaries have relatively permanent flow. Aerial photographs may show 
other indicators commonly used to identify the presence of an 
OHWM.\104\ These indicators may include the destruction of terrestrial 
vegetation, the absence of vegetation in a channel, and stream channel 
morphology with evidence of scour, material sorting, and deposition. 
These indicators from aerial photographs can be correlated to the 
presence of USGS stream data to support an assessment of flow 
characteristics for a tributary.
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    \103\ These tools include local maps, StreamStats by the USGS 
(available at https://streamstats.usgs.gov/ss/), Probability of 
Streamflow Permanence (PROSPER) by the USGS, which provides 
streamflow permanence probabilities during the summer for stream 
reaches in the Pacific Northwest (available at https://www.usgs.gov/centers/wyoming-montana-water-science-center/science/probability-streamflow-permanence-prosper), and NRCS hydrologic tools and soil 
maps. Other tools include regional desktop tools that provide for 
the hydrologic estimation of a discharge sufficient to generate 
intermittent or perennial flow (e.g., a regional regression analysis 
or hydrologic modeling), or modeling tools using drainage area, 
precipitation data, climate, topography, land use, vegetation cover, 
geology, and/or other publicly available information. Some models 
that are developed for use at the reach scale may be localized in 
their geographic scope. NOAA national snow analyses maps can 
facilitate the evaluation of seasonal flow from snowmelt (available 
at https://www.nohrsc.noaa.gov/nsa/), as can NRCS sources (available 
at https://www.wcc.nrcs.usda.gov/snow/), and hydrographs that may 
indicate a large increase in stream discharge due to the late 
spring/early summer thaws of melting snow.
    \104\ See definition of OHWM in section IV.C.8.d of this 
preamble and https://www.erdc.usace.army.mil/Media/Fact-Sheets/Fact-Sheet-Article-View/Article/486085/ordinary-high-water-mark-ohwm-research-development-and-training/.
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    In addition to satellite imagery and aerial photographs, desktop 
tools, such as a regional regression analysis and the Hydrologic 
Modeling System (HEC-HMS), provide for the hydrologic estimation of 
stream discharge in tributaries under regional conditions. The 
increasing availability of LIDAR-derived data can also be used to help 
implement this rule.\105\ Potential LIDAR-indicated tributaries can be 
correlated with aerial photography or high-resolution satellite imagery 
interpretation and USGS stream gage data, to reasonably conclude the 
presence of an OHWM and shed light on the flow characteristics.
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    \105\ Where LIDAR data have been processed to create elevation 
data such as a bare earth model, detailed depictions of the land 
surface are available and subtle elevation changes can indicate a 
tributary's bed and banks and channel morphology. Visible linear and 
curvilinear incisions on a bare earth model can help identify the 
flow characteristics of a water in greater detail than aerial 
photography interpretation alone. Several tools (e.g., TauDEM, 
Whitebox, GeoNet) can assist in developing potential stream networks 
based on contributing areas, curvature, and flowpaths using GIS.
---------------------------------------------------------------------------

    Regional field observations can be used to verify desktop 
assessments of the relative permanence of a tributary, when necessary. 
Geomorphic indicators could include active/relict floodplains, 
substrate sorting, clearly defined and continuous bed and banks, 
depositional bars and benches, and recent alluvial deposits. Hydrologic 
indicators might

[[Page 3088]]

include wrack/drift deposits, hydric soils, or water-stained leaves. 
Biologic indicators could include aquatic mollusks, crayfish, benthic 
macroinvertebrates, algae, and wetland or submerged aquatic plants. As 
noted above, the agencies are developing SDAMs for use throughout the 
country which evaluate and interpret these indicators and can show 
whether tributaries have continuously flowing or standing water year-
round or during certain times of the year for more than a short 
duration in direct response to precipitation. Ultimately, multiple 
indicators, data points, and sources of information may be used to 
determine whether a water, including a tributary, is relatively 
permanent.
iii. Determining Whether a Tributary Meets the Significant Nexus 
Standard
    In evaluating tributaries under the significant nexus standard, the 
agencies will determine whether the tributaries, either alone or in 
combination with similarly situated waters in the region, significantly 
affect the chemical, physical, or biological integrity of paragraph 
(a)(1) waters. See section IV.C.9 of this preamble for additional 
discussion on the definition of ``significantly affect'' in this rule, 
including the factors that will be evaluated and the functions that 
will be assessed as part of a significant nexus analysis. The agencies 
consider tributaries and their adjacent wetlands to be ``similarly 
situated'' waters. The agencies consider similarly situated waters to 
be ``in the region'' when they lie within the catchment area of the 
tributary of interest. Identifying the catchment area for purposes of 
this significant nexus analysis is described below. The agencies 
developed this updated evaluation method from the current pre-2015 
implementation approach informed by their experience, the best 
available science, Supreme Court decisions, and public comments. 
Accordingly, in implementing the significant nexus standard under this 
rule, all tributaries and adjacent wetlands within the catchment area 
of the tributary of interest will be analyzed as part of the 
significant nexus analysis.\106\
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    \106\ This implementation approach to the region for purposes of 
the significant nexus standard is a change from the Rapanos 
Guidance. See section IV.C.9.c of this preamble for additional 
discussion on implementing the significant nexus analysis.
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    For purposes of a significant nexus analysis, the agencies will 
identify the ``region'' as the catchment that drains to and includes 
the tributary of interest. A catchment is the area of the land surface 
that drains to a specific location for a specific hydrologic feature. 
Catchments will be delineated from the downstream-most point of the 
tributary reach of interest and include the land uphill that drains to 
that point. For example, if the tributary of interest is a second order 
stream, the catchment would be delineated from the point that the 
second order stream enters a third order stream. See discussion of 
stream order in section IV.C.4.c.ii.1 of this preamble. Topography and 
landscape position influence the size and configuration of a catchment.
    There are many existing spatial analysis tools that can be used to 
delineate catchments quickly and reliably in most parts of the country. 
USGS topographic maps can be manually interpreted to delineate 
catchments based on the location of the outlet point (the downstream-
most point of the tributary of interest where the tributary enters a 
higher order stream), using calculations informed by topographic 
contours, the alignment of topographic high spots, and grouping of 
lower, valley bottoms. Various GIS tools, web applications, and 
automated modeling systems can also delineate catchments based on one 
or more of the many factors that can influence drainage, including 
surface topography, climate, land use, the presence of hydrologic 
sinks, topology of sewer systems, and design of wastewater treatment 
plant service areas.\107\
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    \107\ NHDPlus provides delineated catchments for individual 
stream segments by linking the mapped stream network to the 
landscape. In addition, StreamStats by the USGS (available at 
https://streamstats.usgs.gov/ss/) is a map-based web tool that can 
delineate drainage areas for streams and estimate flow 
characteristics for selected sites based on stream gage data, basin 
characteristics, climate, etc. EPA's EnviroAtlas Interactive Map 
(available at https://www.epa.gov/enviroatlas/enviroatlas-interactive-map) has a wide variety of tools that can help delineate 
catchments, including a tool that illustrates how precipitation will 
flow over the land surface, mapped elevation profiles for selected 
tributaries, and designations of upstream and downstream watersheds 
within a stream network.
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    After identifying the catchment, the next step is to identify the 
tributaries within the catchment under the agencies' longstanding 
interpretation of tributary, see section IV.C.4.a of this preamble 
above, and any of their adjacent wetlands within the catchment area. 
See section IV.C.5 of this preamble for additional discussion on how to 
identify adjacent wetlands. The agencies' longstanding practice in 
conducting the significant nexus analysis is to assess a tributary in 
combination with wetlands that meet the definition of ``adjacent'' 
under the regulations. Rapanos Guidance at 10. This approach to the 
significant nexus analysis recognizes the ecological relationship 
between the tributaries and their adjacent wetlands, and the role those 
similarly situated waters have in influencing the chemical, physical, 
or biological integrity of paragraph (a)(1) waters. See section 
III.E.iii of the Technical Support Document. For purposes of this rule, 
the agencies will therefore assess the tributaries and their adjacent 
wetlands in a catchment. If the tributaries in the region, including 
the tributary under assessment, have no adjacent wetlands, the agencies 
consider only the factors and functions of the tributaries in 
determining whether there is a significant effect on the chemical, 
physical, or biological integrity of downstream paragraph (a)(1) 
waters. If any of the tributaries in the region, including the 
tributary under assessment, have adjacent wetlands, the agencies will 
consider the factors and functions of the tributaries, including the 
tributary under assessment, together with the functions performed by 
the wetlands adjacent to the tributaries in the catchment, in 
evaluating whether a significant nexus is present.
    In conducting a significant nexus analysis under this rule, the 
agencies will evaluate available hydrologic information (e.g., gage 
data, precipitation records, flood predictions, historic records of 
water flow, statistical data, personal observations/records, etc.) and 
physical indicators of flow including the presence and characteristics 
of a reliable OHWM. To understand the chemical, physical, and 
biological functions provided by tributaries and their adjacent 
wetlands, and the effects those functions have on paragraph (a)(1) 
waters, it is important to use relevant geographic water quality data 
in conjunction with site-specific data from field sampling and 
hydrologic modeling. See section IV.C.9.c of this preamble for 
additional discussion on implementing the significant nexus analysis; 
see also section IV.C.10 of this preamble.
5. Adjacent Wetlands
a. This Rule
    Consistent with the proposal, this rule retains the adjacent 
wetlands provision of the 1986 regulations, with amendments to reflect 
the agencies' interpretation of the statutory limits on the scope of 
the ``waters of the United States'' informed by the law, the science, 
and agency expertise. Aquatic resources that meet this rule's 
definitions of ``wetlands'' and ``adjacent'' are assessed under this 
provision where they are adjacent to traditional navigable waters, the 
territorial seas, interstate waters,

[[Page 3089]]

impoundments of jurisdictional waters, and tributaries.
    As discussed further in section IV.C.8.a of this preamble, in this 
rule the agencies are retaining their longstanding definition of 
``wetlands'' from the 1986 regulations: ``Wetlands means those areas 
that are inundated or saturated by surface or ground water at a 
frequency and duration sufficient to support, and that under normal 
circumstances do support, a prevalence of vegetation typically adapted 
for life in saturated soil conditions. Wetlands generally include 
swamps, marshes, bogs, and similar areas.''
    Additionally, as discussed further in section IV.C.8.b of this 
preamble, in this rule the agencies are retaining their longstanding 
definition of ``adjacent'' unchanged for most of the past 45 years, 
which provides: ``Adjacent means bordering, contiguous, or neighboring. 
Wetlands separated from other waters of the United States by man-made 
dikes or barriers, natural river berms, beach dunes, and the like are 
`adjacent wetlands.' '' Under this definition, adjacency is focused on 
the distance between the wetland and the jurisdictional water. Whether 
the distance between the wetland and the jurisdictional water qualifies 
the wetland as bordering, contiguous, or neighboring (and therefore 
``adjacent'') depends on the factual circumstances. The agencies have 
three well-established criteria to determine adjacency; if any one of 
the criteria is met, the wetland is ``adjacent,'' but may require 
further analysis to determine if it is ``waters of the United States.'' 
See Rapanos Guidance at 5-8. First, there is an unbroken surface or 
shallow subsurface connection to a jurisdictional water, which can be 
established, for example, where the wetland directly abuts the 
jurisdictional water or by a non-jurisdictional physical feature that 
provides the direct connection between the wetland and a jurisdictional 
water, such as a pipe, culvert, non-jurisdictional ditch, or flood 
gate, that has at least periodic flow. Second, the wetland is 
physically separated from a jurisdictional water by human-made dikes or 
barriers, or natural landforms (e.g., river berms, beach dunes). Or 
third, the wetland's proximity to a jurisdictional water is reasonably 
close such that ``adjacent wetlands have significant effects on water 
quality and the aquatic ecosystem.'' Riverside Bayview, 474 U.S. at 135 
n.9. The agencies conclude that close proximity between an adjacent 
wetland and a jurisdictional water means the wetland can modulate water 
quantity or water quality in the jurisdictional water, and the 
jurisdictional water can modulate water quantity or quality in the 
wetland. See section IV.C.5.c of this preamble for further discussion 
on the implementation of this provision and the three criteria. The 
agencies have not established a specific distance limitation in the 
rule beyond which wetlands are never adjacent because whether a wetland 
is reasonably close such that the wetland can modulate water quantity 
or quality in the jurisdictional water or the jurisdictional water can 
modulate water quantity or quality in the wetland as part of the same 
aquatic ecosystem, depends on regional variations in climate, 
landscape, and geomorphology. But the agencies can state based on 
nearly 45 years of implementation of this definition that in a 
substantial number of cases, adjacent wetlands abut (touch) a 
jurisdictional water. And, on the whole, nationwide, adjacent wetlands 
are within a few hundred feet from jurisdictional waters (and in the 
instances where the distance is greater than a few hundred feet, 
adjacency is likely supported by a pipe, non-jurisdictional ditch, 
karst geology, or some other feature that connects the wetland directly 
to the jurisdictional water). Because of regional variability and its 
effects on proximity for purposes of adjacency, wetlands in the arid 
West--where rainfall is generally lower, evaporation rates are higher, 
and riparian areas and floodplains do not extend far from the tributary 
network--are likely to be much closer than a few hundred feet to be 
considered adjacent under this rule. On the other hand, where the 
jurisdictional water is wide, topography is flat lending to larger 
floodplains and riparian areas, and rainfall is higher, wetlands are 
more likely to be determined to be reasonably close where they are a 
few hundred feet from that tributary because the site-specific 
conditions contribute to the close relationship between the wetland and 
the jurisdictional water, including any unbroken surface or shallow 
subsurface hydrologic connections between the waters.
    While bright-line rules (for example, wetlands that are more than a 
specific number of feet from a jurisdictional water are not 
``adjacent'') are easiest to understand and implement, convenience is 
not the only goal the agencies must consider in administering the Clean 
Water Act. Because the relationship between a wetland and a proximate 
jurisdictional water can depend upon a number of site-specific factors, 
like climate, geomorphology, landscapes, hydrology, and size of the 
jurisdictional water (e.g., the ocean compared to a headwater stream), 
and because the central purpose of the Act is to protect the integrity 
of the nation's waters, a more nuanced analysis is required. While 
science says that all things being equal, distance, location in a 
riparian area or floodplain, or discrete hydrologic connections are 
more likely to strengthen the relationship between a wetland and a 
nearby water, science does not provide bright lines on appropriate 
distances to determine adjacency. In implementing this provision over 
the years, the agencies have worked hard to balance the desire for 
clarity and predictability with the agencies' scientific understanding 
of the resources Congress has charged the agencies with protecting. The 
agencies have carefully considered options for nationally applicable 
bright lines with respect to adjacency, such as establishing that any 
wetland within a certain number of feet from a jurisdictional tributary 
is per se jurisdictional, in order to facilitate implementation of the 
Clean Water Act and to minimize the burden on both landowners and the 
agencies to evaluate the scope of ``waters of the United States.'' 
However, the United States is a vast country with many different types 
of waters, watersheds, landscapes, and hydrology. In fact, in the 2015 
Clean Water Rule the agencies sought to establish a distance-based 
bright line for determining adjacency. As discussed in section IV.B.1 
of this preamble, that rule was immediately challenged, and the 
distance-based limitations were a substantial factor in many of the 
challenges. As the Supreme Court itself has recognized, the scope of 
Clean Water Act jurisdiction does not easily lend itself to bright 
lines: ``In sum, we recognize that a more absolute position . . . may 
be easier to administer. But, as we have said, those positions have 
consequences that are inconsistent with major congressional objectives, 
as revealed by the statute's language, structure, and purposes.'' Maui, 
140 S. Ct. at 1477. Ultimately, for purposes of this rule, the agencies 
concluded that there was not a reasoned basis, consistent with the text 
of the statute, to establish such a regulatory bright line.
    The adjacent wetlands provision in the 1986 regulations defined 
``waters of the United States'' to include wetlands adjacent to 
traditional navigable waters, interstate waters, paragraph (a)(3) 
``other waters,'' impoundments of ``waters of the United States,'' 
tributaries, and the territorial seas. This rule provides additional 
constraints on jurisdiction relative to the 1986 regulatory text by

[[Page 3090]]

defining ``waters of the United States'' to include: (1) wetlands 
adjacent to traditional navigable waters, the territorial seas, and 
interstate waters; (2) wetlands adjacent to and with a continuous 
surface connection to relatively permanent paragraph (a)(2) 
impoundments or jurisdictional tributaries when the jurisdictional 
tributaries meet the relatively permanent standard; and (3) wetlands 
adjacent to paragraph (a)(2) impoundments or jurisdictional tributaries 
when the wetlands meet the significant nexus standard. In other words, 
for wetlands adjacent to waters that are not paragraph (a)(1) waters, 
an additional showing of a continuous surface connection to a 
relatively permanent water or of a significant nexus to a paragraph 
(a)(1) water is required. The determination of whether a wetland is 
``adjacent'' is distinct from whether an ``adjacent'' wetland meets the 
relatively permanent standard; however, wetlands that have a continuous 
surface connection to a relatively permanent water meet the definition 
of ``adjacent'' and thus are a subset of adjacent wetlands. See section 
IV.C.5.c of this preamble for further information related to 
implementing the final rule's adjacent wetlands provision.
    Under this rule, the relatively permanent standard and the 
significant nexus standard are independent jurisdictional standards. 
Under the relatively permanent standard for adjacent wetlands, wetlands 
meet the continuous surface connection requirement if they physically 
abut, or touch, a relatively permanent paragraph (a)(2) impoundment or 
a jurisdictional tributary when the jurisdictional tributary meets the 
relatively permanent standard, or if the wetlands are connected to 
these waters by a discrete feature like a non-jurisdictional ditch, 
swale, pipe, or culvert. A natural berm, bank, dune, or similar natural 
landform between an adjacent wetland and a relatively permanent water 
does not sever a continuous surface connection to the extent it 
provides evidence of a continuous surface connection. Again, the 
determination of whether a wetland is ``adjacent'' under the rule is 
distinct from whether an ``adjacent'' wetland has a continuous surface 
connection. See section IV.C.5.c of this preamble, below, for further 
discussion of implementation of the final rule's adjacent wetlands 
provision.
    The agencies have amended the regulatory text from the proposed 
rule to be clearer that a wetland adjacent to but lacking a continuous 
surface connection to a tributary that is relatively permanent must be 
assessed under the significant nexus standard. For example, if a 
wetland is ``neighboring'' to a tributary that is relatively permanent, 
and thus ``adjacent,'' but lacks a continuous surface connection to 
that tributary, the wetland would need to be assessed under the 
significant nexus standard in order to determine its jurisdictional 
status. This is consistent with pre-2015 practice under the Rapanos 
Guidance for wetlands adjacent to relatively permanent tributaries and 
was the agencies' intent under the proposed rule language. See Rapanos 
Guidance at 8; 86 FR 69423 (``Wetlands adjacent to relatively permanent 
tributaries but that lack a continuous surface connection to such 
waters would then be assessed under the significant nexus [standard], 
along with the tributary.'').
    In addition, under this rule, wetlands adjacent only to paragraph 
(a)(5) waters cannot be considered for jurisdiction under the paragraph 
(a)(4) adjacent wetlands category, which represents a change from the 
1986 regulations. Instead, such wetlands could be considered for 
jurisdiction solely under paragraph (a)(5) of this rule.
    Further, in this rule, the agencies are deleting the parenthetical 
from the 1986 regulations that limited the scope of jurisdictional 
adjacent wetlands to wetlands adjacent to waters ``(other than waters 
that are themselves wetlands)'' for the reasons discussed below.
b. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    The agencies received numerous comments on the scope and 
implementation of the adjacent wetlands provision.
i. Comments on the Adjacent Wetlands Provision
    The agencies received a wide range of comments on adjacent 
wetlands. Some commenters stated that they agreed with the agencies' 
approach in the proposed rule for adjacent wetlands, with several 
adding that they believed the proposed rule's approach to adjacency was 
consistent with prior practice, the relevant case law, the statute, the 
Constitution, or congressional intent. Other commenters disagreed and 
stated that the agencies' approach was not consistent with case law, 
the statute, the Constitution, or congressional intent. Many of those 
commenters stated that wetlands should only be jurisdictional if they 
meet the relatively permanent standard. Other commenters requested 
greater jurisdictional protections for wetlands due to the many 
functions that they provide that benefit downstream waters, with some 
commenters requesting that adjacent wetlands be treated as 
categorically jurisdictional, similar to the 2015 Clean Water Rule.
    After careful consideration of public comments and for the reasons 
described in this preamble, the agencies are promulgating the adjacent 
wetlands provision of this rule with minimal changes to the proposed 
rule. For wetlands adjacent to paragraph (a)(1) waters, adjacency alone 
supports jurisdiction. For wetlands that are adjacent to waters that 
are not paragraph (a)(1) waters, like tributaries, this rule 
establishes an additional limitation on jurisdiction. In that case, the 
adjacent wetlands are jurisdictional only if they meet either the 
relatively permanent standard or the significant nexus standard. The 
agencies agree with commenters who stated that the proposed rule's 
approach to adjacent wetlands was generally consistent with prior 
practice and consistent with the relevant case law, the statute, the 
Constitution, and congressional intent, and thus disagree with 
commenters who took the contrary view. This rule defines ``waters of 
the United States'' to include adjacent wetlands and reflects the 
agencies' interpretation of the statutory limits on the scope of the 
``waters of the United States'' informed by the text of the relevant 
provisions of the Clean Water Act and the statute as a whole, relevant 
Supreme Court decisions, the scientific record, the agencies' 
experience and technical expertise, and consideration of public 
comments on the proposed rule. The agencies disagree with commenters 
who stated that only adjacent wetlands that meet the relatively 
permanent standard should be considered jurisdictional. As discussed 
further in section IV.A.3.a.ii of this preamble, the agencies have 
concluded that the relatively permanent standard is administratively 
useful but is insufficient as the sole standard for geographic 
jurisdiction under the Clean Water Act because it is inconsistent with 
the Act's text and objective. Protecting only waters that meet the 
relatively permanent standard also runs counter to the scientific 
principles underlying protection of water quality. The agencies thus 
are promulgating an approach to adjacent wetlands that includes, but 
that is not limited to, the relatively permanent standard. The 
ecological relationship between jurisdictional waters and their 
adjacent wetlands is well documented in the scientific literature and 
reflects their physical proximity as well as shared hydrological and 
biological characteristics. The scientific literature

[[Page 3091]]

also supports the conclusion that adjacent wetlands, either alone or in 
combination with similarly situated waters, provide many important 
functions that can significantly affect the chemical, physical, and 
biological integrity of paragraph (a)(1) waters. See Technical Support 
Document section III.B. Section IV.A of this preamble provides 
additional information about the legal basis for the agencies' 
conclusions in this rule and the scientific support for the rule's 
provisions regarding adjacent wetlands. The agencies are not making 
additional categorical determinations of jurisdiction based on the 
significant nexus standard, as described further in section IV.A of 
this preamble. Even under the 2020 NWPR, which purported to enhance 
clarity, a landowner could not tell simply by looking at their property 
whether it contained ``waters of the United States'' because, in the 
case of adjacent wetlands, it was necessary to determine (1) whether 
the property contained a wetland as defined in the regulations, (2) 
whether there was evidence of a continuous surface connection between 
the wetland and a water that was part of the tributary network of a 
traditional navigable water or the territorial seas, (3) whether there 
was evidence that the continuous surface connection occurred in a 
``typical year,'' as the rule defined that term, and (4) in the case of 
a continuous surface connection based on inundation, whether the 
inundation originated in the jurisdictional water (relevant to 
adjacency under that rule) or the wetland (irrelevant to adjacency 
under that rule).
    The challenge inherent in establishing bright lines to address the 
complex and variable ways in which waters move in different regions 
across the country is longstanding. As the Supreme Court itself has 
recognized, the scope of Clean Water Act jurisdiction does not easily 
lend itself to bright lines: ``In sum, we recognize that a more 
absolute position . . . may be easier to administer. But, as we have 
said, those positions have consequences that are inconsistent with 
major congressional objectives, as revealed by the statute's language, 
structure, and purposes.'' Maui, 140 S. Ct. at 1477. Further, as early 
Supreme Court decisions recognized, the Clean Water Act replaced a 
system whereby water quality protection had to be resolved through 
litigation in which courts had to apply ``often vague and indeterminate 
nuisance concepts and maxims of equity jurisprudence.'' City of 
Milwaukee, 451 U.S. at 317. The Clean Water Act replaced this 
unpredictable and inefficient approach with ``a comprehensive 
regulatory program supervised by an expert administrative agency,'' 
id., including a ``uniform system of interstate water pollution 
regulation,'' Arkansas v. Oklahoma, 503 U.S. 91, 110 (1992). Shrinking 
Federal jurisdiction, as the 2020 NWPR did, for example, would place 
many waters back within the ``vague and indeterminate'' legal regime 
that the Supreme Court recognized the Clean Water Act was designed to 
replace. See 451 U.S. at 317.
    The agencies also received a variety of comments critiquing or 
supporting various past practice and rulemaking approaches to adjacency 
including the pre-2015 regulatory regime, the 2015 Clean Water Rule, 
and the 2020 NWPR. The agencies are retaining their longstanding 
definition of adjacency and establishing an approach to adjacency that 
is generally consistent with the pre-2015 regulatory regime, with some 
changes to implementation discussed below. The agencies are rejecting 
certain aspects of the 2020 NWPR's approach to adjacent wetlands for 
the reasons discussed in this section and section IV.B.3 of this 
preamble. The definition of ``adjacent wetlands'' in the 2020 NWPR 
failed to advance the objective of the Clean Water Act. It also was 
inconsistent with scientific information about the important effects of 
wetlands that do not abut jurisdictional waters and that lack evidence 
of specific surface water connections to such waters on the integrity 
of paragraph (a)(1) waters. In addition, key elements of the 2020 
NWPR's definition of ``adjacent wetlands'' were extremely difficult to 
implement. These deficiencies are reflected in substantial losses of 
Federal protections on the ground. See section IV.B.3 of this preamble. 
The agencies are maintaining the approach of the pre-2015 regulatory 
regime and the 2015 Clean Water Rule under which wetlands adjacent to 
traditional navigable waters, the territorial seas, and interstate 
waters are jurisdictional without need for further determinations, but 
the agencies are not determining that any additional adjacent wetlands 
are categorically jurisdictional in this rule. The agencies have 
authority to determine which tributaries and their adjacent wetlands 
are jurisdictional either through regulations or adjudication. See 
Rapanos, 547 U.S. at 780-81 (Kennedy, J., concurring in the judgment); 
see also NLRB v. Bell Aerospace Co., 416 U.S. 267, 294 (1974). With 
respect to wetlands adjacent to waters other than paragraph (a)(1) 
waters, the agencies have decided to proceed through case-specific 
jurisdictional determinations under this rule, rather than through 
categorical determinations by rule.
    The agencies will continue to assert jurisdiction over wetlands 
adjacent to traditional navigable waters, the territorial seas, and 
interstate waters without need for further assessment, as they did 
under the 1986 regulations and the Rapanos Guidance. Indeed, in 
Rapanos, at least five Justices agreed that wetlands adjacent to 
traditional navigable waters are ``waters of the United States.'' See 
Rapanos, 547 U.S. at 780 (Kennedy, J., concurring in the judgment) 
(``As applied to wetlands adjacent to navigable-in-fact waters, the 
Corps' conclusive standard for jurisdiction rests upon a reasonable 
inference of ecologic interconnection, and the assertion of 
jurisdiction for those wetlands is sustainable under the Act by showing 
adjacency alone.''), id. at 810 (Stevens, J., dissenting) (``Given that 
all four Justices who have joined this opinion would uphold the Corps' 
jurisdiction in both of these cases--and in all other cases in which 
either the plurality's or Justice Kennedy's test is satisfied--on 
remand each of the judgments should be reinstated if either of those 
tests is met.''); see also Riverside Bayview, 474 U.S. at 134 (``[T]he 
Corps' ecological judgment about the relationship between waters and 
their adjacent wetlands provides an adequate basis for a legal judgment 
that adjacent wetlands may be defined as waters under the Act.''); 
Rapanos Guidance at 5. Moreover, ample scientific information makes 
clear that the health and productivity of rivers and lakes, including 
paragraph (a)(1) waters, depends upon the functions provided by 
upstream tributaries, adjacent wetlands, and paragraph (a)(5) waters. 
Under this rule, the agencies also define ``waters of the United 
States'' to include wetlands adjacent to the territorial seas without 
need for further assessment, as they did under the 1986 regulations, as 
the territorial seas are categorically protected under the Clean Water 
Act. Additionally, under this rule the agencies continue to define 
``waters of the United States'' to include wetlands adjacent to 
interstate waters without need for further assessment since interstate 
waters, like traditional navigable waters and the territorial seas, are 
waters clearly protected by the Clean Water Act. See section IV.C.2 of 
this preamble for further discussion of traditional navigable waters, 
the territorial seas, and interstate waters.
    The agencies are retaining the 1986 regulations' coverage of 
wetlands adjacent to paragraph (a)(2)

[[Page 3092]]

impoundments and wetlands adjacent to tributaries to paragraph (a)(2) 
impoundments, updated to include the requirement that the wetlands also 
meet either the relatively permanent or significant nexus standard. As 
discussed above in section IV.C.3 of this preamble, the agencies' 
longstanding interpretation of the Clean Water Act is that ``waters of 
the United States'' remain ``waters of the United States'' even if 
impounded. Since the impoundment does not ``denationalize'' the 
``waters of the United States,'' see S.D. Warren, 547 U.S. at 379 n.5, 
the agencies similarly interpret the Clean Water Act to continue to 
protect wetlands adjacent to the paragraph (a)(2) impoundment and 
adjacent to jurisdictional tributaries to the impoundment where those 
wetlands meet the relatively permanent standard or the significant 
nexus standard. See section IV.C.3 of this preamble for additional 
discussion of impoundments under this rule.
    The agencies are also deleting the cross reference to paragraph 
(a)(5) waters as waters to which wetlands may be adjacent to be 
determined ``waters of the United States'' under the adjacent wetlands 
category of this rule. This change reflects the agencies' consideration 
of the jurisdictional concerns and limitations of the statute, informed 
by SWANCC and Rapanos. The agencies have concluded that a provision 
that authorizes consideration of jurisdiction over adjacent wetlands 
that meet the relatively permanent or significant nexus standard when 
assessed based simply on connections to paragraph (a)(5) waters would 
have too tenuous a connection to paragraph (a)(1) waters. Rather, any 
such wetlands that are adjacent only to paragraph (a)(5) waters would 
be assessed themselves under paragraph (a)(5) of this rule to determine 
if they meet the relatively permanent or significant nexus standard. 
For example, a wetland adjacent to a lake that meets the significant 
nexus standard under paragraph (a)(5) would itself need to be assessed 
under paragraph (a)(5) to determine whether it significantly affects 
the chemical, physical, or biological integrity of a paragraph (a)(1) 
water. See section IV.C.6.c of this preamble for further discussion on 
implementation of paragraph (a)(5) waters.
    The agencies have removed the parenthetical ``(other than waters 
that are themselves wetlands)'' from the regulatory text because it has 
caused confusion for the public and the regulated community and is 
unnecessary. The parenthetical from the 1986 regulations limited the 
scope of jurisdictional adjacent wetlands to wetlands adjacent to 
waters ``(other than waters that are themselves wetlands).'' Under that 
provision, a wetland was not jurisdictional simply because it was 
adjacent to another adjacent wetland or to a wetland jurisdictional 
under paragraph (a)(3) of the 1986 regulations. The provision has 
created confusion under the pre-2015 regulatory regime, as some have 
asserted that a wetland that is indeed adjacent to a jurisdictional 
tributary, but that is separated from that tributary by another 
adjacent wetland, should not be determined to be a jurisdictional 
adjacent wetland because of that parenthetical. Several commenters 
discussed the parenthetical in the 1986 regulation's ``adjacent 
wetlands'' category. Most of those commenters were in favor of removing 
the parenthetical, claiming that it created ``confusion'' and citing 
concerns that the parenthetical could improperly limit jurisdiction of 
wetlands. Other commenters voiced support for keeping the 
parenthetical. Some even suggested that the parenthetical flatly 
excluded all wetlands that are adjacent to other wetlands, regardless 
of any other considerations. These interpretations are inconsistent 
with the agencies' intent and longstanding interpretation of the 
parenthetical. See Universal Welding & Fabrication, Inc. v. U.S. Army 
Corps of Eng'rs, 708 Fed. Appx. 301, 303 (9th Cir. 2017) (observing 
that ``[d]espite the subject wetland's adjacency to another wetland, 
the Corps determined that its regulatory authority was not precluded by 
the parenthetical language within [section] 328.3(a)(7), which it 
interpreted as prohibiting the exercise of jurisdiction over a wetland 
only if based upon that wetland's adjacency to another wetland'' and 
holding that the Corps' interpretation is ``the most reasonable reading 
of the regulation's text''). Therefore, to streamline the regulation 
and provide additional clarity, the agencies have deleted the text of 
the parenthetical in this rule. In addition, wetlands adjacent to 
interstate wetlands or wetlands adjacent to tidal wetlands (which are 
traditional navigable waters) are jurisdictional under this rule, 
consistent with the 1986 regulations and longstanding practice.
ii. Comments on the Interpretation and Implementation of the Adjacent 
Wetlands Provision
    The agencies will continue to implement a number of longstanding 
interpretations of ``adjacent'' based on scientific principles and 
practical administration of the definition with this rule. As stated 
previously, the agencies consider wetlands ``adjacent'' if one of the 
following three criteria is satisfied. First, there is an unbroken 
surface or shallow subsurface connection to jurisdictional waters. All 
wetlands that directly abut jurisdictional waters have an unbroken 
surface or shallow subsurface connection because they physically touch 
the jurisdictional water. Wetlands that do not directly abut a 
jurisdictional water may have an unbroken surface or shallow subsurface 
connection to jurisdictional waters. Water does not need to be 
continuously present in the surface or shallow subsurface connection. 
Second, they are physically separated from jurisdictional waters by 
human-made dikes or barriers, or natural landforms (e.g., river berms, 
beach dunes). Or third, their proximity to a jurisdictional water is 
reasonably close. Wetlands that meet one of these three criteria are 
considered bordering, contiguous, or neighboring for purposes of this 
rule.
    Several commenters provided input on these three criteria. Some 
commenters stated that shallow subsurface hydrologic connections are 
appropriate to consider for adjacency, while others stated that such 
connections should not be considered. Several commenters stated that 
there are regional differences in proximity relevant to adjacency. Some 
commenters stated that wetlands should be considered adjacent even if 
they are separated by human-made dikes or barriers, natural river 
berms, beach dunes and the like, while other commenters did not support 
that view.
    The agencies agree with commenters who stated that shallow 
subsurface connections can be relevant to adjacency and will continue 
to use the criteria from pre-2015 practice that an unbroken shallow 
subsurface connection between a wetland and another water can 
demonstrate adjacency.
    While this rule does not explicitly identify regional factors that 
influence what is ``reasonably close'' for purposes of adjacency, the 
agencies recognize there may be site-specific factors (e.g., 
topography) that influence what is ``reasonably close.'' This rule does 
not establish specific distance limitations for adjacency, which helps 
ensure that site-specific and regional factors can be considered when a 
wetland is being evaluated (see section IV.C.5.c of this preamble, 
below).
    The agencies agree with commenters who supported the 1986 
regulation's definition of ``adjacent'' to include wetlands even if 
they are separated by

[[Page 3093]]

natural landforms or human-made barriers for the reasons discussed in 
sections IV.A.2.b.ii (explaining that the agencies' longstanding 
definition of ``adjacent,'' which includes such wetlands, is a 
reasonable foundation for this rule), and IV.C.8.b of this preamble, 
and section III.B.ii of the Technical Support Document.
c. Implementation
    Under this provision of the rule, wetlands adjacent to traditional 
navigable waters, the territorial seas, or interstate waters are 
jurisdictional and do not need further analysis to determine if they 
are ``waters of the United States.'' Further, wetlands adjacent to 
paragraph (a)(2) impoundments and to jurisdictional tributaries are 
assessed for jurisdiction under the relatively permanent standard or 
significant nexus standard. Wetlands adjacent to but lacking a 
continuous surface connection with tributaries that are relatively 
permanent must be assessed under the significant nexus standard.
i. Determining the Presence of an Adjacent Wetland
    Before determining if a wetland is jurisdictional, the agencies 
first determine if the wetland in question meets the definition of 
``wetlands'' under this rule (see section IV.C.8.a of this preamble).
    In identifying wetlands, the agencies will ordinarily consider all 
wetlands within a wetland mosaic collectively. The agencies have long 
considered wetland mosaics to be delineated as one wetland. Wetland 
mosaics are landscapes where wetland and non-wetland components are too 
closely associated to be easily delineated or mapped separately, and 
the wetlands in the mosaic generally act as a single ecological unit. 
In certain regions where wetland mosaics are common, Corps regional 
wetland delineation manuals address how to delineate such wetlands. 
Longstanding practice is that wetlands in the mosaic are not 
individually delineated, but that the agencies consider the entire 
mosaic and estimate percent wetland in the mosaic. See Technical 
Support Document section IV.A.iii. These longstanding implementation 
approaches for purposes of jurisdictional determinations are supported 
by the science (see Technical Support Document section IV.A.iii) and 
the technical expertise the agencies have developed through years of 
performing these assessments.
    Once a feature is identified as a wetland, if the wetland itself is 
not jurisdictional under paragraph (a)(1) of this rule as a traditional 
navigable water (such as a tidal wetland) or an interstate water, the 
agencies assess whether it is adjacent to a traditional navigable 
water, territorial sea, interstate water, paragraph (a)(2) impoundment, 
or jurisdictional tributary. Wetlands are ``adjacent'' if they are 
``bordering, contiguous, or neighboring.'' The agencies consider the 
entire wetland to be ``adjacent'' if any part of the wetland is 
``adjacent.''
    Under this rule's definition and consistent with the agencies' 
longstanding definition, adjacency is focused on the distance between 
the wetland and the jurisdictional water. Whether the distance between 
the wetland and the jurisdictional water qualifies the wetland as 
bordering, contiguous, or neighboring (and therefore ``adjacent'') 
depends on the factual circumstances, so the agencies will assess 
adjacency using the three criteria noted above in section IV.C.5.a of 
this preamble. This section of the preamble explains each of the 
criteria in further detail. These criteria are consistent with the text 
of the regulation, the underlying scientific rationale for defining 
``waters of the United States'' to include adjacent wetlands, and pre-
2015 practice. See Rapanos Guidance at 5-6.
    The longstanding definition, by its terms, does not require flow 
from the wetland to the jurisdictional water or from the jurisdictional 
water to the wetland (although such flow in either direction can be 
relevant to the determination of adjacency). The Supreme Court in 
Riverside Bayview in deferring to the Corps' ecological judgment about 
the relationship between waters and their adjacent wetlands as an 
``adequate basis for a legal judgment that adjacent wetlands may be 
defined as waters under the Act,'' rejected an argument that such 
wetlands had to be the result of flow in a particular direction to be 
adjacent: ``This holds true even for wetlands that are not the result 
of flooding or permeation by water having its source in adjacent bodies 
of open water. The Corps has concluded that wetlands may affect the 
water quality of adjacent lakes, rivers, and streams even when the 
waters of those bodies do not actually inundate the wetlands. For 
example, wetlands that are not flooded by adjacent waters may still 
tend to drain into those waters. In such circumstances, the Corps has 
concluded that wetlands may serve to filter and purify water draining 
into adjacent bodies of water, and to slow the flow of surface runoff 
into lakes, rivers, and streams and thus prevent flooding and erosion. 
In addition, adjacent wetlands may `serve significant natural 
biological functions, including food chain production, general habitat, 
and nesting, spawning, rearing and resting sites for aquatic . . . 
species.' '' 447 U.S at 134 (citing 33 CFR 320.4(b)(2)(iv), (v), (vii) 
(1985)).
    Wetlands with an unbroken surface or shallow subsurface connection 
to jurisdictional waters are adjacent, including those wetlands that 
directly abut a jurisdictional water (i.e., they are not separated by 
uplands, a berm, dike, or similar barrier from the OHWM of the water to 
which they are adjacent). All wetlands that directly abut 
jurisdictional waters have an unbroken surface or shallow subsurface 
connection because they physically touch the jurisdictional water. An 
unbroken surface or shallow subsurface connection to jurisdictional 
waters can also be established by a non-jurisdictional physical feature 
or discrete conveyance that supports at least periodic flow between the 
wetland and a jurisdictional water, such as a pipe, culvert, non-
jurisdictional ditch, or flood gate. Water does not have to be 
continuously present in this hydrologic connection and the flow between 
the wetland and the jurisdictional water may move in either or both 
directions.
    A shallow subsurface hydrologic connection is predominantly lateral 
water flow through a shallow subsurface layer. Such flows may be found, 
for example, in wetlands on slopes, where water seeps through surface 
soils to downstream waters, in soils with a restrictive horizon, in the 
hyporheic zone, or in karst systems. A shallow subsurface connection 
also exists, for example, when the adjacent wetland and the water to 
which it is adjacent are in contact with the same shallow aquifer or 
with the same shallow water table which fluctuates within the soil 
profile, sometimes rising to or near the ground surface. Shallow 
subsurface connections can also be maintained as water moves through 
karst topography, and through confined human-made subsurface conveyance 
systems such as drain tiles and storm sewers. Shallow subsurface 
connections may be found below the ordinary root zone (below 12 
inches), where other wetland delineation factors may not be present. A 
variety of factors may reflect the presence of a shallow subsurface 
connection, including position of the wetland in the landscape (for 
example, on a slope above the jurisdictional waters), stream 
hydrographs, soil surveys (for example, exhibiting indicators of high 
transmissivity over an impermeable

[[Page 3094]]

layer), and information indicating that the water table in the stream 
is lower than the shallow subsurface. The agencies may also utilize 
direct observations in the field or tracer studies to demonstrate 
shallow subsurface flow. Shallow subsurface connections convey water 
quickly through the soil and impact surface water directly within hours 
or days rather than the months or years it may take long pathways to 
reach surface waters. However, neither shallow subsurface connections 
nor any type of groundwater, shallow or deep, are themselves ``waters 
of the United States.'' Some examples of wetlands that are adjacent 
under the final rule due to an unbroken surface or shallow subsurface 
connection include wetlands that are connected to a tributary via karst 
topography, which provide a direct subsurface hydrologic connection 
between the wetlands and the tributary and that is traceable via a dye 
test, even if those wetlands are more than several hundred feet from 
the tributary; and wetlands within a couple of hundred feet of a 
tributary, where the subsurface hydrologic connection is demonstrated 
via soil maps which demonstrate continuous hydric soils with indicators 
of high transmissivity over an impermeable layer between the tributary 
and the proximate wetlands. See Technical Support Document section 
III.B.ii for additional information on surface and shallow subsurface 
hydrologic connections.
    If a wetland is separated from a jurisdictional water by man-made 
dikes or barriers, natural river berms, beach dunes, and the like, then 
the wetlands are adjacent under this rule, consistent with the 1986 
regulations. No additional identification of a hydrologic connection 
between the wetland and the jurisdictional water is required for such 
wetlands to be considered adjacent. For example, a wetland that is 
separated from a jurisdictional tributary simply by a 40-foot road 
meets the longstanding definition of adjacent. It is also important to 
note that natural river berms are formed by sediment deposits 
accumulating at or near stream banks during flood events. Such berms 
vary in height from inches to feet, and also can be quite wide. With 
respect to beach dunes and similar natural landforms, more than one 
dune may exist between an adjacent wetland and jurisdictional water 
(including primary and secondary dunes), because beach dunes typically 
function as an interdunal system (particularly on barrier islands). For 
example, interdunal wetlands which are located between dune ridges 
would be adjacent.
    In some cases, a wetland may be separated from a jurisdictional 
water by more than one human-made dike or barrier or multiple types of 
barriers and landforms (e.g., a wetland separated by a human-made 
barrier and a natural river berm). The agencies will assess such 
wetlands consistent with the other adjacency criteria previously 
described (i.e., by identifying the presence of an unbroken surface or 
shallow subsurface connection or determining that their proximity to a 
jurisdictional water is reasonably close).
    For purposes of determining whether a wetland is ``adjacent,'' 
artificial structures do not divide a wetland if a hydrologic 
connection is maintained between the divided portions of the wetland. 
Rather, the wetland is treated as one wetland. For example, if a 
wetland is divided by a road, a culvert could maintain a hydrologic 
connection. The agencies may also consider if a subsurface hydrologic 
connection is maintained, using indicators such as hydric soils, the 
permeability of the artificial structure, and/or the permeability of 
the soils below the artificial structure.
    Wetlands are also adjacent when their proximity to a jurisdictional 
water is reasonably close. The Supreme Court in Riverside Bayview 
deferred to the Corps' judgment that adjacent wetlands ``that form the 
border of or are in reasonable proximity to'' other ``waters of the 
United States'' ``may be defined as waters under the Act.'' Riverside 
Bayview, 474 U.S. at 134. Where the wetland is reasonably close to the 
jurisdictional water, the agencies have concluded that ``adjacent 
wetlands have significant effects on water quality and the aquatic 
ecosystem.'' Id. at 135 n.9. The close proximity between an adjacent 
wetland and a jurisdictional water means the wetland can modulate water 
quantity and water quality in the jurisdictional water, and the 
jurisdictional water can modulate water quantity and water quality in 
the wetland. For example, wetlands typically help to store floodwaters, 
pollutants, and sediments that could otherwise reach the jurisdictional 
water to which they are adjacent. They can also provide flow 
contributions to the jurisdictional waters to which they are adjacent 
during high hydroperiods, where water spills from the wetland to the 
nearby jurisdictional water, and such contributions of flow are 
facilitated by the wetland's close proximity to the jurisdictional 
water. The proximate jurisdictional waters can serve as important 
sources of water for adjacent wetlands, for example, through 
overtopping events where flow from the jurisdictional waters is stored 
in the wetlands. While under this rule the agencies are not 
establishing distance limits for adjacency, the agencies recognize that 
as the distance between the wetland and jurisdictional water increases, 
the reasonableness of the connection between the waters will generally 
decrease, particularly in the absence of the type of surface or shallow 
subsurface connections described above, and a finding of adjacency is 
less likely. The distance between a jurisdictional water and its 
adjacent wetlands may vary by region, as well as based on site-specific 
factors within regions. In practice, under this criterion, the agencies 
have found that adjacent wetlands are on the whole, nationwide, within 
a few hundred feet of jurisdictional waters. This can vary from site to 
site and region to region due to differences in climate, geomorphology, 
landscape setting, hydrology, soils, vegetation, elevation, size of the 
jurisdictional water, and other site-specific variables.
    Field data, including visual observations, can assist with 
determining if a wetland is adjacent. In addition, a variety of remote 
tools can help to assess adjacency, including maps, high-resolution 
elevation data, aerial photographs, and high-resolution satellite 
imagery. For example, visual observation, NWI and USGS topographic 
maps, elevation data, and NHD data may identify a physical barrier or 
illustrate the location of the traditional navigable water, territorial 
sea, interstate water, paragraph (a)(2) impoundment, or jurisdictional 
tributary; the wetland's proximity to the jurisdictional water; and the 
nature of topographic relief between the two aquatic resources. Visual 
observations, aerial photographs, or high-resolution satellite imagery 
may illustrate hydrophytic vegetation from the boundary (e.g., OHWM for 
non-tidal waters or high tide line for tidal waters) of the traditional 
navigable water, the territorial seas, the interstate water, the 
paragraph (a)(2) impoundment, or the jurisdictional tributary to the 
wetland boundary, or the presence of water or soil saturation. Soil 
samples or NRCS soil maps may identify the presence of hydric soil 
types, soil saturation, or potential surface or subsurface hydrologic 
connections. Additionally, methods that overlay depressions on the 
landscape with hydric soils and hydrophytic vegetation can be used to 
identify likely wetlands and hydrologic connections. Field work can 
help

[[Page 3095]]

confirm the presence and location of the OHWM or high tide line of the 
jurisdictional water and can provide additional information about the 
wetland's potential adjacency to that water.\108\
---------------------------------------------------------------------------

    \108\ Field work may include, e.g., traversing the landscape 
from the traditional navigable water, territorial sea, interstate 
water, paragraph (a)(2) impoundment, or jurisdictional tributary to 
the wetland and examining topographic and geomorphic 
characteristics, as well as hydrologic and biologic indicators.
---------------------------------------------------------------------------

ii. Determining Whether an Adjacent Wetland Meets the Relatively 
Permanent Standard
    Wetlands that are adjacent to paragraph (a)(1) waters are 
jurisdictional without the need for further analysis. Wetlands adjacent 
to paragraph (a)(2) impoundments and wetlands adjacent to 
jurisdictional tributaries must meet a second requirement to be 
jurisdictional as ``waters of the United States'' under this rule--they 
must satisfy either the relatively permanent standard or the 
significant nexus standard.
    Under this rule, adjacent wetlands meet the relatively permanent 
standard if they have a continuous surface connection to a relatively 
permanent paragraph (a)(2) impoundment or a jurisdictional tributary 
when the jurisdictional tributary meets the relatively permanent 
standard. As discussed previously in this section of this preamble, 
wetlands that have a continuous surface connection to such waters are a 
subset of adjacent wetlands. Wetlands that do not have a continuous 
surface connection but are adjacent to paragraph (a)(2) impoundments or 
jurisdictional tributaries will be evaluated for jurisdiction under the 
significant nexus standard. See also section IV.C.5.c.iii of this 
preamble.
    A continuous surface connection does not require a constant 
hydrologic connection. Rather, the agencies will identify a continuous 
surface connection consistent with the Rapanos plurality opinion, which 
indicates that the continuous surface connection requirement is a 
``physical-connection requirement.'' 547 U.S. at 751 n.13; see also 
Rapanos Guidance at 7. Wetlands meet the continuous surface connection 
requirement if they physically abut or touch a relatively permanent 
paragraph (a)(2) impoundment or a jurisdictional tributary when the 
jurisdictional tributary meets the relatively permanent standard. 
Wetlands also meet the continuous surface connection requirement if 
they are connected to relatively permanent waters by a discrete feature 
like a non-jurisdictional ditch, swale, pipe, or culvert. This is 
because a ditch or other such feature can serve as a physical 
connection that maintains a continuous surface connection between an 
adjacent wetland and a relatively permanent water. This approach to the 
continuous surface connection is supported by the scientific 
literature, case law, and the agencies' technical expertise and 
experience. As the Court of Appeals for the Sixth Circuit has 
explained, ``it does not make a difference whether the channel by which 
water flows from a wetland to a navigable-in-fact waterway or its 
tributary was manmade or formed naturally.'' United States v. Cundiff, 
555 F.3d 200, 213 (6th Cir. 2009) (``Cundiff'') (holding wetlands were 
jurisdictional under the Rapanos plurality where plaintiff created a 
continuous surface connection by digging ditches to enhance the acid 
mine drainage into the creeks and away from his wetlands).
    Similarly, a natural berm, bank, dune, or similar natural landform 
between an adjacent wetland and a relatively permanent water does not 
sever a continuous surface connection to the extent it provides 
evidence of a continuous surface connection. This approach is 
consistent with the agencies' interpretation in the 2020 NWPR that 
natural berms and similar natural landforms ``are indicators of a 
direct hydrologic surface connection as they are formed through 
repeated hydrologic events.'' 85 FR 22311 (April 21, 2020). As the 2020 
NWPR explained, ``a natural river berm can be created by repeated 
flooding and sedimentation events when a river overtops its banks and 
deposits sediment between the river and a wetland.'' Id. (citing 
Science Report at A-7). The 2020 NWPR noted that the adjacent wetland 
could have been formed at the same time as or after the formation of 
the natural river berm due to repeated flooding and the impeded return 
flow created by the berm. Natural banks can also provide evidence of a 
continuous surface connection because the processes that result in 
their formation can also be representative of the interconnected 
relationship between the wetlands and the relatively permanent water. 
Adjacent wetlands may be separated by a bank from a relatively 
permanent water due to an elevation difference between the bank and the 
water (e.g., when the stream is incised). The surface water flow of a 
tributary over time can erode a channel, which creates a bank 
separating the tributary from the adjacent wetland. See 85 FR 22311 
(April 21, 2020). In addition, the presence of a beaver dam between a 
wetland and a relatively permanent water can be evidence of a 
continuous surface connection between the two features, even if the dam 
itself blocks surface hydrologic flow for periods of time. Beach dunes 
may also separate adjacent wetlands and relatively permanent waters. 
Beach dunes are sometimes formed through wind erosion which results in 
the sand surface interacting with the water table, providing enough 
hydrology to create wetlands. Beach dunes may also be formed when water 
levels drop in lakes or from historic glacial retreat. Many interdunal 
wetlands have seasonally variable hydroperiods where they may be dry 
during periods of low rainfall. All of these processes and the 
resulting natural berm, bank, dune, or similar natural landform 
indicate that the wetlands are integrated and ``inseparably bound up'' 
with the relatively permanent waters. See 85 FR 22280 (April 21, 2020) 
(citing Rapanos, 547 U.S. at 732 (Scalia, J., plurality opinion)). The 
agencies recognize that not all natural berms, banks, dunes, and 
similar natural landforms demonstrate evidence of a continuous surface 
connection. For example, an adjacent wetland may be separated from a 
relatively permanent water by a relict landform like a natural berm 
that no longer interacts hydrologically with the tributary network. 
Such relict barriers do not demonstrate evidence of a continuous 
surface connection and may in fact sever the continuous surface 
connection.
    While natural barriers may at times occur within a floodplain, the 
existence of a floodplain (and other land masses similar to a 
floodplain, such as a riparian area or fluvial terrace) generally is 
not sufficient to indicate a continuous surface connection. Wetlands 
separated from jurisdictional waters by cliffs, bluffs, or canyon walls 
also typically do not have a continuous surface connection, and thus 
would be assessed under the significant nexus standard. However, if 
these cliffs, bluffs, or canyon walls have gaps or built structures 
(e.g., culverts, pipes, or waterfalls) that provide for a continuous 
surface connection between the adjacent wetlands and the relatively 
permanent water, this type of connection would satisfy the physical 
connection requirement for a continuous surface connection. The same is 
true for dikes or other artificial barriers with gaps or structural 
components that allow for a continuous surface connection. For example, 
an upland levee that separates an adjacent wetland from a tributary 
that is relatively permanent may have gaps along the length of the 
levee that

[[Page 3096]]

provide for a physical connection between the wetlands and the 
tributary that satisfies the requirement for a continuous surface 
connection.
    Some commenters asserted that the agencies' use of the relatively 
permanent standard in the proposed rule is inconsistent with the 
Rapanos plurality opinion because it does not require a continuous 
hydrologic connection for adjacent wetlands to be jurisdictional, with 
one commenter referencing the agencies' statement in the proposed rule 
that a continuous surface connection ``does not require surface water 
to be continuously present between the wetland and the tributary.'' 
Another commenter asserted that the proposed rule's approach to 
adjacent wetlands is inconsistent with the Rapanos plurality opinion 
because it allows for the continuous surface connection requirement to 
be satisfied by physical connections such as non-jurisdictional ditches 
with an irregular flow surface connection requirement. The agencies 
disagree that the approach in this rule is inconsistent with the 
plurality opinion. The plurality opinion indicates that ``continuous 
surface connection'' is a ``physical connection requirement.'' Rapanos, 
547 U.S. at 751 n.13 (referring to ``our physical-connection 
requirement'' and later stating that Riverside Bayview does not reject 
``the physical-connection requirement''). This approach to the 
continuous surface connection requirement is consistent with the 
Rapanos Guidance. Rapanos Guidance at 7 & n.28. A continuous surface 
connection is not the same as a continuous surface water connection, by 
its terms and in effect. Therefore, because the plurality opinion 
requires only a ``continuous surface connection,'' the relatively 
permanent standard in this rule, consistent with the plurality opinion, 
does not require surface water to be continuously present between the 
wetland and the tributary. The agencies also disagree that it is 
inconsistent with the plurality opinion for adjacent wetlands to be 
considered to meet the continuous surface connection requirement if 
they are connected to relatively permanent waters by a discrete feature 
like a non-jurisdictional ditch, swale, pipe, or culvert. This is 
because a ditch or other such feature can serve as a physical 
connection that maintains a continuous surface connection between an 
adjacent wetland and a relatively permanent water. This approach to the 
continuous surface connection is supported by the scientific 
literature, case law, and the agencies' technical expertise and 
experience. See Cundiff, 555 F.3d at 213.
    The agencies agree with commenters who stated that a continuous 
surface connection does not require the continuous presence of surface 
water between the adjacent wetland and relatively permanent paragraph 
(a)(2) impoundment or jurisdictional tributary when the jurisdictional 
tributary meets the relatively permanent standard, and the agencies 
continue this longstanding approach in this rule. The agencies' 
approach is consistent with science, as well as the longstanding 
regulatory definition of ``wetlands,'' which does not require such 
aquatic resources to contain surface water. See 33 CFR 328.3(b)(2014) 
and 40 CFR 232.2 (2014)(defining wetlands as ``areas that are inundated 
or saturated by surface or ground water at a frequency and duration 
sufficient to support a prevalence of vegetation typically adapted for 
life in saturated soil conditions'' (emphasis added)); see also 
Technical Support Document section III.B. Since wetlands frequently do 
not contain surface water, a requirement for continuous surface water 
between a relatively permanent water and adjacent wetlands would be 
illogical as a scientific and practical matter.
    The agencies have a variety of tools for determining whether 
adjacent wetlands have a continuous surface connection to relatively 
permanent waters, or if they are separated from them by natural 
landforms or artificial barriers, including the same tools used to 
establish adjacency. Visual observations, high-resolution satellite 
imagery, NRCS soil maps, USGS topographic maps, and NHD data may show 
soil saturation, surface flow patterns and infrastructure crossings 
(e.g., roads) that can be used to indicate possible culvert locations. 
Visual observations, high-resolution satellite imagery, elevation data 
such as LIDAR-based topographic models, and USGS topographic maps may 
identify the presence of swales that are located between a wetland and 
a relatively permanent water. Similar tools (described below) and 
visual observations can be used to identify the potential presence of 
natural landforms that can maintain a continuous surface connection and 
the potential presence of breaks that may sever a continuous surface 
connection. Distinguishing between landforms like upland breaks and 
natural berms can be facilitated by assessing their linear extent and 
continuity, or observations on how they hydrologically interact with an 
associated relatively permanent water.
    To assess whether wetlands are separated from relatively permanent 
waters by natural landforms or artificial barriers, the agencies can 
rely upon a variety of tools. For example, USGS topographic maps may 
show topographic highs between the wetland and relatively permanent 
water, or simple indices can be calculated based on topography to 
indicate where these separations occur and their linear extent. FEMA 
flood zone or other floodplain maps may indicate constricted 
floodplains along the length of the tributary channel with physical 
separation of flood waters. High-resolution elevation data can 
illustrate topographic highs between a wetland and tributary channel 
that extend along the length of a tributary's channel. Aerial 
photographs or high-resolution satellite imagery may illustrate upland 
vegetation along the tributary channel between the wetland and 
tributary channel, or bright soil signatures indicative of higher 
ground. NRCS soil maps may identify mapped linear, upland soil types 
along the tributary channel. Field work may help to confirm the 
presence and location of the OHWM of a tributary that is relatively 
permanent. In addition, field work may confirm whether there is a 
continuous physical connection between the wetland and the tributary, 
or identify breaks that may sever the continuous surface 
connection.\109\
---------------------------------------------------------------------------

    \109\ Field work may include, e.g., traversing the landscape 
from the tributary to the wetland and examining topographic and 
geomorphic characteristics, the linear extent of those features, as 
well as hydrologic and biologic indicators.
---------------------------------------------------------------------------

iii. Determining Whether an Adjacent Wetland Meets the Significant 
Nexus Standard
    The agencies note again that the determination of adjacency and the 
determination of a significant nexus are different and that there are 
two key differences. First, adjacency is about the relationship between 
a wetland and a jurisdictional water and is based on reasonable 
proximity, whereas significant nexus is about the functions provided by 
an adjacent wetland to a paragraph (a)(1) water-the significant nexus 
assessment is not to the jurisdictional water to which the wetland is 
adjacent (if the jurisdictional water is a paragraph (a)(1) water, it 
is jurisdictional without a case-specific significant nexus 
assessment). Second, a wetland must meet the adjacency standard on its 
own, whereas a significant nexus assessment is based on whether an 
adjacent wetland alone or in combination with other similarly situated 
waters significantly affects the

[[Page 3097]]

integrity of a paragraph (a)(1) water. Once a wetland has been 
determined to be ``adjacent,'' if the adjacent wetland does not meet 
the relatively permanent standard, the agencies will conduct a 
significant nexus analysis to assess if the wetland is jurisdictional.
    Under the regulations, the adjacent wetlands which do not meet the 
relatively permanent standard and for which a significant nexus 
analysis must be conducted are: (1) adjacent wetlands that lack a 
continuous surface connection to a relatively permanent paragraph 
(a)(2) impoundment or a jurisdictional tributary when the 
jurisdictional tributary meets the relatively permanent standard, and 
(2) wetlands adjacent to a paragraph (a)(2) impoundment or a tributary 
when the paragraph (a)(2) impoundment or the tributary is not 
relatively permanent. In evaluating such adjacent wetlands under the 
significant nexus standard, the agencies will determine whether the 
wetlands, either alone or in combination with similarly situated waters 
in the region, significantly affect the chemical, physical, or 
biological integrity of paragraph (a)(1) waters. See section IV.C.9 of 
this preamble for additional discussion on the definition of 
``significantly affect'' in this rule, including the factors that will 
be evaluated and the functions that will be assessed as part of a 
significant nexus analysis. The agencies consider tributaries and their 
adjacent wetlands to be ``similarly situated'' waters. The agencies 
consider similarly situated waters to be ``in the region'' when they 
lie within the catchment area of the tributary of interest. Therefore, 
in implementing the significant nexus standard under this rule, all 
tributaries and adjacent wetlands within the catchment area of the 
tributary of interest will be analyzed as part of the significant nexus 
analysis.
    For a significant nexus analysis, the region would be the catchment 
that drains to and includes the tributary to which the wetland in 
question is adjacent. A catchment is the area of the land surface that 
drains to a specific location for a specific hydrologic feature, such 
as a tributary. Catchments will be delineated from the downstream-most 
point of the tributary reach to which the wetland is adjacent and 
include the land uphill that drains to that point, as discussed in 
further detail in section IV.C.4.c of this preamble and its 
subsections.
    After identifying the catchment, the next step is to identify the 
tributaries within the catchment under the agencies' longstanding 
interpretation of tributary, see section IV.C.4.a of this preamble, and 
their adjacent wetlands within the catchment area, see section 
IV.C.5.c.i of this preamble. When evaluating whether an adjacent 
wetland meets the significant nexus standard, the agencies will 
consider the factors in the final rule, along with the functions of the 
tributaries in the catchment together with the functions performed by 
the wetlands adjacent to the tributaries in the catchment, including 
the subject wetland, in relation to the chemical, physical, or 
biological integrity of the paragraph (a)(1) water. This approach to 
the significant nexus analysis recognizes the ecological relationship 
between wetlands and the tributaries to which they are adjacent, and 
the role those similarly situated waters have in influencing the 
chemical, physical, or biological integrity of paragraph (a)(1) waters. 
See Technical Support Document section III.E.
    Section IV.C.9.c of this preamble discusses a variety of tools and 
sources of information that can be used to assess significant effects 
on the chemical, physical, and biological integrity of paragraph (a)(1) 
waters. Remote tools, field indicators and observational methods, and 
datasets can all assist in determining whether adjacent wetlands meet 
the significant nexus standard. In addition, a variety of modeling 
approaches can be used to quantify the connectivity and cumulative 
effects of wetlands, including non-floodplain wetlands, on other 
waters, as discussed further in section IV.A.v of the Technical Support 
Document.\110\
---------------------------------------------------------------------------

    \110\ Some examples include the Soil and Water Assessment Tool 
(SWAT, available at https://swat.tamu.edu/), the Hydrologic 
Simulation Program in Fortran (available at https://www.epa.gov/ceam/hydrological-simulation-program-fortran-hspf), and DRAINMOD for 
Watersheds (DRAINWAT, available at https://www.bae.ncsu.edu/agricultural-water-management/drainmod/). Other examples of models 
applicable to identifying effects of wetlands on downstream waters 
include the USGS hydrologic model MODFLOW (available at https://www.usgs.gov/mission-areas/water-resources/science/modflow-and-related-programs?qt-science_center_objects=0#qt-science_center_objects) and the USGS flow simulation model VS2DI 
(available at https://www.usgs.gov/software/vs2di-version-13).
---------------------------------------------------------------------------

6. Waters Not Identified in Paragraphs (a)(1) Through (4)
a. This Rule
    Paragraph (a)(5) of this rule defines ``waters of the United 
States'' to include ``intrastate lakes and ponds, streams, or wetlands 
not identified in paragraphs (a)(1) through (4)'' that meet either the 
relatively permanent standard or the significant nexus standard. Waters 
in this category in the 1986 regulations were sometimes referred to as 
``(a)(3) waters'' or ``other waters.'' With this rule, the agencies 
have made important changes to the 1986 regulations to reflect the 
agencies' construction of the statutory limits on the scope of ``waters 
of the United States'' informed by the relevant provisions of the Clean 
Water Act and the statute as a whole, the scientific record, relevant 
Supreme Court precedent, and the agencies' experience and technical 
expertise after more than 45 years of implementing the longstanding 
pre-2015 regulations defining ``waters of the United States.'' Of 
particular importance, the agencies have replaced the broad Commerce 
Clause basis for jurisdiction from the 1986 regulations for waters not 
identified in other provisions of the definition with the relatively 
permanent standard and the significant nexus standard. Because the 
relatively permanent standard and the significant nexus standard 
require connections to a paragraph (a)(1) water, and the significant 
nexus standard further requires that waters significantly affect 
paragraph (a)(1) waters, this provision of the rule is substantially 
narrower than the 1986 regulations. The 1986 regulations, for example, 
authorized the assertion of jurisdiction over waters from which fish or 
shellfish are or could be taken and sold in interstate or foreign 
commerce.
    The agencies are including a provision for intrastate lakes and 
ponds, streams, or wetlands not identified in paragraphs (a)(1) through 
(4) of the rule because such waters can provide functions that restore 
and maintain the chemical, physical, and biological integrity of 
traditional navigable waters, the territorial seas, and interstate 
waters. See section IV.A.2.c.iii of this preamble. For example, a large 
lake that is very close to a tributary or paragraph (a)(1) water, but 
that is not part of the tributary system, would be non-jurisdictional 
if the agencies did not include the category for assessing such waters 
under paragraph (a)(5) in this rule, even if that lake provides many 
functions that significantly affect a traditional navigable water.
    The agencies have streamlined and clarified the provision for 
paragraph (a)(5) waters as compared to the 1986 regulations. The 
agencies have added the requirement that these waters must meet either 
the relatively permanent standard or significant nexus standard to be 
``waters of the United States.'' In addition, the agencies have deleted 
the non-exclusive list of ``other waters'' that was featured in 
paragraph (a)(3) of the 1986 regulations. Under the final rule's new 
paragraph (a)(5) provision, only ``intrastate lakes and ponds, streams, 
or wetlands not identified in paragraphs

[[Page 3098]]

(a)(1) through (4)'' can be assessed for jurisdiction under the 
relatively permanent standard or significant nexus standard. As 
discussed further below, however, the agencies have concluded that the 
more specific water types previously listed in paragraph (a)(3) of the 
1986 regulations nonetheless generally fall within one of the four 
water types listed in paragraph (a)(5) of this rule.
    Finally, the agencies have moved the provision for paragraph (a)(5) 
waters to the end of the section of the regulation which defines the 
categories of jurisdictional waters, since paragraph (a)(5) waters are 
those that are not covered by the preceding categories. As a result, 
``other waters'' are now in paragraph (a)(5) of this rule. In light of 
these changes to the regulatory text, the agencies refer to these 
waters as ``those not identified in paragraphs (a)(1) through (4)'' or 
``paragraph (a)(5) waters'' for purposes of this rule.
    Waters assessed under paragraph (a)(5) meet the relatively 
permanent standard if they are relatively permanent, standing or 
continuously flowing bodies of water with a continuous surface 
connection to a paragraph (a)(1) water or a tributary that is 
relatively permanent. The agencies will assess waters under paragraph 
(a)(5) to determine if they are relatively permanent using a similar 
approach to the one described for tributaries in section IV.C.4 of this 
preamble, and the agencies will assess a continuous surface connection 
between waters assessed under paragraph (a)(5) and a paragraph (a)(1) 
water or a tributary that is relatively permanent using the approach 
described for adjacent wetlands in section IV.C.5 of this preamble. 
Waters assessed under paragraph (a)(5) meet the significant nexus 
standard if they significantly affect the chemical, physical, or 
biological integrity of a traditional navigable water, the territorial 
seas, or an interstate water. See section IV.C.6.c of this preamble for 
further discussion on implementation of these standards for waters 
assessed under paragraph (a)(5). The agencies also note that the 
characteristics of a water considered for jurisdiction under paragraph 
(a)(5) can change over time such that it meets the requirements for 
consideration under another category of ``waters of the United 
States.'' For example, a river that does not drain to a paragraph 
(a)(1) water could potentially become a traditional navigable water, 
for instance, if it is impounded and becomes a navigable-in-fact 
reservoir. Such water would then be assessed as a traditional navigable 
water under paragraph (a)(1)(i) of the final rule. Similarly, a wetland 
that historically was not adjacent can become an adjacent wetland, for 
example, if a ditch is constructed that connects the wetland to a 
jurisdictional tributary. Such a wetland would then be considered under 
paragraph (a)(4) of the final rule due to the unbroken surface 
connection to a jurisdictional water via the ditch.
b. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    The agencies received numerous comments on whether to include a 
category for waters that do not fall within one of the more specific 
categories in the definition of ``waters of the United States'' and the 
standard upon which to base jurisdiction over such waters, as well as 
on implementation of this provision of the rule.
i. Comments on the Provision for Waters That Do Not Fall Within One of 
the More Specific Categories
    Some commenters expressed general support for including a category 
for waters that do not fall within one of the more specific categories 
in this rule, while others opposed including such a category. Many 
commenters requested clarification of the category for waters that do 
not fall within one of the more specific categories. Many commenters 
addressed the agencies' legal authority to assert jurisdiction over 
waters that do not fall within one of the more specific categories. 
Some commenters asserted that following the Supreme Court's decisions 
in SWANCC and Rapanos, the agencies lack authority to assert 
jurisdiction over such waters. Other commenters stated that the 
proposed rule's approach to such waters is legally defensible. Several 
commenters further stated that the proposed rule does not go far enough 
in protecting waters that do not fall within one of the more specific 
categories and asserted that broader protection would be consistent 
with Rapanos, SWANCC, and Maui.
    The agencies disagree that the agencies lack authority to assert 
jurisdiction over waters that do not fall within one of the more 
specific categories. The agencies' regulations have long had provisions 
for case-specific determinations of jurisdiction over waters that did 
not fall within the other jurisdictional categories. See section 
IV.A.2.b of this preamble. Such waters under this rule can be assessed 
under paragraph (a)(5), and they are only jurisdictional if they meet 
the relatively permanent standard or significant nexus standard. The 
agencies have thus established limits on the scope of these waters 
consistent with the law, the science, and agency expertise. See section 
IV.A of this preamble. In addition, the agencies have carefully 
considered the limitations on their authority under the Clean Water 
Act, especially concerning paragraph (a)(5) waters. The agencies have 
made a number of changes to the 1986 regulations that collectively 
ensure the definition of ``waters of the United States'' remains well 
within statutory and constitutional limits. Those changes include 
replacing the broad Commerce Clause basis for jurisdiction over 
paragraph (a)(5) waters with the narrower relatively permanent and 
significant nexus standards, eliminating jurisdiction over tributaries 
and adjacent wetlands based on their connection to paragraph (a)(5) 
waters, and eliminating jurisdiction by rule over impoundments of 
paragraph (a)(5) waters. See sections IV.A.3.a.i, IV.C.3, IV.C.4, and 
IV.C.5 of this preamble. In addition, as discussed further in the 
implementation section below, the agencies are intending to continue a 
thoughtful, careful approach to implementation and coordination for 
paragraph (a)(5) waters.
    The agencies also received numerous comments on the standard to be 
used for determining jurisdiction over waters that do not fall within 
one of the more specific categories. Some commenters supported the 
proposed rule's requirement that such waters meet either the relatively 
permanent standard or the significant nexus standard. However, other 
commenters did not support this approach. One commenter recommended 
that the agencies not apply the relatively permanent standard to waters 
that do not fall within one of the more specific categories because it 
would be duplicative. Specifically, the commenter asserted that waters 
that meet the relatively permanent standard as described in the 
proposed rule would always meet the jurisdictional criteria for another 
rule category. A few commenters disagreed with applying the significant 
nexus standard to waters that do not fall within one of the more 
specific categories, asserting that it goes beyond the scope of 
jurisdiction contemplated by Justice Kennedy in Rapanos. Many other 
commenters opposed the proposed rule's removal of the interstate and 
foreign commerce jurisdictional basis for protecting waters that do not 
fall within one of the more specific categories. Commenters expressed 
that this basis would protect many important waterways which provide 
valuable public health,

[[Page 3099]]

agricultural, recreational, drinking water, ecological, and economic 
services important to local, regional, and national interests.
    Under the 1986 regulations, ``other waters'' (such as intrastate 
rivers, lakes, and wetlands that were not otherwise jurisdictional 
under other sections of the rule) could be determined to be 
jurisdictional if the use, degradation, or destruction of the water 
could affect interstate or foreign commerce. This rule amends the 1986 
regulations to delete all the provisions referring to authority over 
activities that ``could affect interstate or foreign commerce'' and 
replaces them with the relatively permanent and significant nexus 
standards. Thus, this rule would provide for case-specific analysis of 
waters not addressed by any other provision of the definition to 
determine whether they are ``waters of the United States'' under the 
relatively permanent or significant nexus standards.
    The text of the 1986 regulations reflected the agencies' 
interpretation at the time, based primarily on the legislative history 
of the Clean Water Act, that the jurisdiction of the Act extended to 
the maximum extent permissible under the Commerce Clause of the 
Constitution. While SWANCC did not invalidate the 1986 regulations' 
``other waters'' provision or any other parts of the 1986 regulations' 
definition of ``waters of the United States,'' the Court cautioned that 
that it ``assum[es] that Congress does not casually authorize 
administrative agencies to interpret a statute to push the limit of 
congressional authority.'' 531 U.S. at 172-73. Therefore, the agencies 
conclude that asserting jurisdiction over non-navigable, intrastate 
waters based solely on whether the use, degradation, or destruction of 
the water could affect interstate or foreign commerce pushes the limit 
of the Clean Water Act where those waters do not significantly affect 
paragraph (a)(1) waters. This rule thus replaces the interstate 
commerce test with the relatively permanent and significant nexus 
standards. As discussed in section IV.A of this preamble, the agencies 
have concluded that the significant nexus standard is consistent with 
the statutory text and legislative history, advances the objective of 
the Clean Water Act, is informed by the scientific record and Supreme 
Court case law, and appropriately considers the policies of the Act. 
The relatively permanent standard is included in the rule because it 
provides important efficiencies and additional clarity for regulators 
and the public by more readily identifying a subset of waters that will 
virtually always significantly affect paragraph (a)(1) waters. Thus, 
this rule gives effect to the Clean Water Act's broad terms and 
environmentally protective aim as well as its limitations.
    Accordingly, waters that do not fall within one of the more 
specific categories identified in paragraphs (a)(1) through (4) of this 
rule may still be jurisdictional. This is consistent with the text of 
the statute, relevant Supreme Court case law, and the science. See 
section IV.A of this preamble and Technical Support Document section 
III.D. The Rapanos plurality concluded, ``relatively permanent, 
standing or continuously flowing bodies of water,'' 547 U.S. at 739, 
that are connected to traditional navigable waters, id. at 742, and 
waters with a ``continuous surface connection'' to such water bodies, 
id. (Scalia, J., plurality opinion), are ``waters of the United 
States'' under the relatively permanent standard. Without paragraph 
(a)(5), a relatively permanent lake that is not a tributary and is not 
a wetland, but which nonetheless has a continuous surface connection to 
a traditional navigable water, could not be evaluated for jurisdiction. 
Justice Kennedy concluded that SWANCC held that ``to constitute ` 
``navigable waters'' ' under the Act, a water or wetland must possess a 
`significant nexus' to waters that are or were navigable in fact or 
that could reasonably be so made.'' Id. at 759 (citing SWANCC, 531 U.S. 
at 167, 172). Many lakes and ponds that are not part of the tributary 
system and that do not qualify as a paragraph (a)(1) water can only be 
assessed under paragraph (a)(5) of this rule. There is no basis in the 
statute or the science for excluding a lake or pond from the definition 
of ``waters of the United States'' that is situated on the landscape in 
a similar manner as an adjacent wetland, solely because it is a lake 
and not a wetland.
    Multiple commenters stated that the proposed rule's inclusion of 
waters that do not fall within one of the more specific categories 
would impermissibly assert jurisdiction over a wide range of features 
that are far from traditional navigable waters and that have only minor 
volumes of flow. A few commenters suggested that although the proposed 
rule recognizes the importance of the strength of connection, 
particularly the distance of such waters to navigable waters, it 
suggests that the agencies may rely too much on scientific principles 
when making jurisdictional determinations in a manner that improperly 
expands the scope of the agencies' authority. Another commenter 
asserted that the agencies should not consider water functions that 
indicate isolation between water features as a basis for finding a 
significant nexus for waters that do not fall within one of the more 
specific categories.
    The agencies disagree that this rule's category for waters that do 
not fall within one of the more specific categories, paragraph (a)(5), 
improperly expands the scope of their authority. The agencies have not 
only narrowed this category from the 1986 regulations by replacing the 
broad Commerce Clause provisions with the relatively permanent standard 
and the significant nexus standard, but they have also made additional 
changes from the 1986 regulations in order to ensure that they are not 
pushing the outer limits of the authority granted to them by Congress 
under the Clean Water Act. See section IV.A.3.a.i of this preamble. 
Impoundments of waters jurisdictional under paragraph (a)(5) no longer 
remain jurisdictional by rule. Tributaries to waters jurisdictional 
under paragraph (a)(5) are not tributaries under paragraph (a)(3) of 
this rule and must themselves be assessed under paragraph (a)(5). 
Wetlands adjacent to waters jurisdictional under paragraph (a)(5) are 
not adjacent wetlands under paragraph (a)(4) of this rule and must 
themselves be assessed under paragraph (a)(5). In addition, as 
discussed further below, the agencies have established enhanced 
coordination procedures for waters assessed under the significant nexus 
standard under paragraph (a)(5) in order to ensure that such 
jurisdictional determinations are consistent with this rule. The 
agencies have also carefully defined ``significantly affect,'' and have 
drawn upon the scientific literature to identify the factors and 
functions that will be used to make significant nexus determinations. 
See section IV.C.9 of this preamble. In addition, the agencies will be 
appropriately relying on both scientific principles and requirements of 
the relatively permanent standard or the significant nexus standard 
when assessing jurisdiction under this provision of the rule. As 
described in section IV.A.2.c.iii of this preamble, paragraph (a)(5) 
waters can provide functions that restore and maintain the chemical, 
physical, and biological integrity of paragraph (a)(1) waters. 
Therefore, the agencies have determined that including the category for 
paragraph (a)(5) waters in this rule best advances the objective of the 
Clean Water Act. The agencies disagree with the commenter that asserted 
that the agencies should not consider water functions that indicate 
isolation between water features as a basis for finding a significant 
nexus. That

[[Page 3100]]

position is contrary to Justice Kennedy's opinion on the role the 
absence of a hydrologic connection should play in a significant nexus 
analysis. See Rapanos, 547 U.S. at 786 (Kennedy, J., concurring in the 
judgment) (``Given the role wetlands play in pollutant filtering, flood 
control, and runoff storage, it may well be the absence of hydrologic 
connection (in the sense of interchange of waters) that shows the 
wetlands' significance for the aquatic system.''). That argument is 
also inconsistent with the science regarding the functions that waters 
that do not fall within one of the more specific categories provide to 
paragraph (a)(1) waters. See Technical Support Document section III.D.
    Many commenters stated that certain types of wetlands should be 
categorically protected in the rule category for waters that do not 
fall within one of the more specific categories, such as Carolina and 
Delmarva bays, pocosins, prairie potholes, vernal pools, and other non-
floodplain wetlands, because they provide functions that protect the 
chemical, physical, or biological integrity of paragraph (a)(1) waters. 
These commenters also stated that these waters provide valuable public 
health, agricultural, recreational, drinking water, ecological, and 
economic services important to local, regional, and national interests. 
The agencies acknowledge commenters who discussed the functions that 
these waters can provide. Agencies may choose to proceed via rulemaking 
or adjudication. NLRB v. Bell Aerospace Co., 416 U.S. 267, 294 (1974) 
(``[T]he choice between rulemaking and adjudication lies in the first 
instance within the [agency's] discretion.''). With respect to the 
significant nexus standard in particular, Justice Kennedy stated that 
the agencies could proceed to determine waters jurisdictional through 
regulations or adjudication. See 547 U.S. at 780-81. The agencies have 
concluded that adjudication of which waters assessed under paragraph 
(a)(5) are within Clean Water Act protections through case-specific 
application of the significant nexus standard or the relatively 
permanent standard under this rule, is appropriate. Therefore, the 
agencies are not categorically including or excluding waters that do 
not fall within one of the more specific categories as jurisdictional 
under this rule. See also section III.D of the Technical Support 
Document for more information on the agencies' rationale for evaluating 
waters under paragraph (a)(5). Waters assessed under paragraph (a)(5) 
will be evaluated using the relatively permanent standard or 
significant nexus standard to determine their jurisdictional status.
    Some commenters expressed that the category for waters that do not 
fall within one of the more specific categories is too ambiguous or too 
inclusive of waters that they believed should not be protected. The 
agencies disagree with commenters who asserted that the category for 
waters that do not fall within one of the more specific categories 
should be removed, or that the category is too confusing or overly 
broad. Waters assessed under paragraph (a)(5) in this rule are only 
jurisdictional if they meet the relatively permanent standard or the 
significant nexus standard. The agencies have also amended this 
provision of the rule to more clearly identify the types of waters 
addressed by this provision of the rule. Additionally, a category for 
waters that do not fall within one of the more specific categories is a 
longstanding and generally familiar category of waters included in the 
definition of ``waters of the United States'' under the 1986 
regulations. The agencies have extensive experience implementing the 
relatively permanent standard and significant nexus standard for 
wetlands, streams, lakes, and ponds, which are the types of resources 
that are assessed under paragraph (a)(5) of this rule, and so will be 
able to use their experience and implementation resources to ensure 
consistency of jurisdictional determinations.
    The 1986 regulations contained a non-exclusive list of water types 
that could be jurisdictional if they were not jurisdictional under the 
other provisions of the definition: ``[a]ll other waters such as 
intrastate lakes, rivers, streams (including intermittent streams), 
mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, 
playa lakes, or natural ponds.'' The agencies sought comment in the 
proposed rule on whether it would be helpful to the public to delete 
the list of water types or to otherwise provide more clarity to the 
list of water types in the regulation. Commenters provided a variety of 
perspectives on the specific list of waters in the 1986 regulations. 
Several commenters recommended that the agencies clarify that the 
example list of waters is illustrative and not exhaustive. Commenters 
requested additions to the example list of waters, such as Delmarva 
bays, vernal pools, and seepage lakes. Other commenters requested that 
certain features be excluded from the example list of waters, such as 
prairie potholes. Some commenters expressed confusion as to why the 
example list from the 1986 regulations included ``intermittent 
streams'' but not ``ephemeral streams.''
    In this rule, the agencies have made changes to the 1986 
regulations to clarify the list of water types that can be 
jurisdictional under this provision, and to clarify that waters 
assessed under paragraph (a)(5) include waters that do not meet the 
requirements under paragraphs (a)(1) through (4) of this rule. The list 
of water types in the 1986 regulations led to confusion as it was 
sometimes incorrectly read as an exclusive list. There has also been 
confusion about some of the listed water types. For example, the list 
includes intermittent streams and was meant to allow for jurisdictional 
evaluation of intermittent streams that do not fall within the other 
categories (such as intermittent streams that are not tributaries to 
the requisite water types but which under the 1986 regulations could 
affect interstate commerce and under the proposed rule could meet the 
significant nexus standard). The list was not meant to imply that 
intermittent streams were not jurisdictional under the tributary 
provision of the 1986 regulations. In addition, a flowing aquatic 
feature that is human-made or human-altered but which is neither a 
jurisdictional tributary nor an excluded ditch would be assessed as a 
stream under paragraph (a)(5).
    Paragraph (a)(5) of this rule identifies as ``waters of the United 
States'' ``intrastate lakes and ponds, streams, or wetlands not 
identified in paragraphs (a)(1) through (4)'' that meet either the 
relatively permanent standard or significant nexus standard. Removing 
the list of water types from the 1986 regulations is not meant to imply 
that any of the water types listed in the 1986 regulations are not 
potentially subject to jurisdiction; rather, the revised list of water 
types is intended to more clearly inform the public of the types of 
waters that can be assessed for jurisdiction under paragraph (a)(5), 
and in this rule the list is intended to be exclusive. The revised list 
is also streamlined for clarity. The agencies have concluded that the 
more specific water types previously listed in paragraph (a)(3) of the 
1986 regulations fall within one of the four water types in the rule. 
For example, prairie potholes were in the list of water types in the 
1986 regulations and, depending upon the characteristics of a 
particular prairie pothole, they may fall within the wetlands water 
type on the list (where they meet the regulatory definition of 
wetlands) or they may be lakes or ponds. Other examples include 
sloughs, as they typically fall within the wetlands water type or the 
streams

[[Page 3101]]

water type, and playa lakes, which may fall within the lakes or ponds 
water type depending upon their size. Finally, the list of water types 
included in paragraph (a)(5) does not reflect a conclusion that these 
waters are categorically jurisdictional; rather, these waters are only 
jurisdictional if the subject waters meet either the relatively 
permanent standard or the significant nexus standard.
ii. Comments on Interpretation and Implementation of Paragraph (a)(5) 
Waters
    The agencies received many comments supporting, opposing, or 
recommending changes related to the implementation of the category for 
waters that do not fall within one of the more specific categories. 
Some commenters asserted that the proposed rule lacked sufficient 
implementation guidance, and one commenter specifically stated that the 
proposed rule lacked sufficient guidance as to how the agencies will 
apply the significant nexus standard to waters that do not fall within 
one of the more specific categories. A few commenters recommended an 
approach for including waters that do not fall within one of the more 
specific categories as jurisdictional in a manner similar to adjacent 
wetlands, with some arguing that this approach would streamline the 
permitting process, and others stating general support for this 
approach. A number of commenters recommended that the agencies adopt 
regionalized implementation approaches for certain types of waters that 
do not fall within one of the more specific categories, such as prairie 
potholes, Carolina Bays, and Indiana dune and swale wetland complexes. 
The agencies acknowledge commenters who requested additional 
implementation guidance in the final rule, and additional guidance has 
been added to this rule including for the significant nexus standard. 
See section IV.C.6.c of this preamble for additional discussion on 
implementation of the significant nexus standard for waters assessed 
under paragraph (a)(5). While the agencies' intended implementation 
approach for paragraph (a)(5) waters has some differences from the 
implementation approach for adjacent wetlands, as described further 
below, the agencies have determined that the approach is reasonable and 
implementable. This rule does not preclude the agencies from taking 
into account regional considerations as part of the significant nexus 
analysis, but the agencies are not explicitly including regional 
criteria in the rule to ensure they have the flexibility to address 
local conditions.
    Under the pre-2015 regulatory regime, the agencies established 
coordination procedures for paragraph (a)(3) ``other waters.'' See 68 
FR 1991, 1995 (January 15, 2003) (``SWANCC Guidance'') (``[F]ield staff 
should seek formal project-specific Headquarters approval prior to 
asserting jurisdiction over such waters, including permitting and 
enforcement actions.''). Several commenters stated that the agencies 
should retain the requirement for field staff to request headquarters 
review of approved jurisdictional determinations for waters that do not 
fall within one of the more specific categories in this rule. These 
commenters stated that review of the scientific justification for a 
conclusion under the significant nexus standard must be conducted by 
senior officials for accuracy and thoroughness, and agency headquarters 
should provide such oversight. In contrast, several commenters stated 
that the agencies should abandon the requirement for field staff to 
request headquarters review of approved jurisdictional determinations 
for waters that do not fall within one of the more specific categories. 
These commenters stated that headquarters review should not be 
necessary because agency field staff have considerable experience with 
and expertise regarding the significant nexus standard. The commenters 
also stated that requiring headquarters review would equate to 
continued exclusion of waters that do not fall within one of the more 
specific categories but should be provided Clean Water Act protection. 
Finally, commenters asserted that reducing the number of approved 
jurisdictional determinations needing review by agency headquarters 
would streamline the permitting process.
    As discussed further below, the agencies have established 
coordination procedures under which the agencies' headquarters will 
review all draft approved jurisdictional determinations for waters 
assessed under paragraph (a)(5) based on the significant nexus 
standard. This approach represents enhanced oversight by headquarters 
staff over approved jurisdictional determinations for waters assessed 
under paragraph (a)(5) to ensure implementation consistency and to 
gather more robust data about the number and types of waters under 
paragraph (a)(5) evaluated by the agencies, any regional or geographic 
issues, and the information and implementation resources needed to make 
approved jurisdictional determinations for this category.
c. Implementation
    This rule provides for case-specific analysis of waters not 
addressed by any other provision of the definition to determine whether 
they are ``waters of the United States'' under the relatively permanent 
or significant nexus standards. Waters assessed under paragraph (a)(5) 
meet the relatively permanent standard if they are relatively 
permanent, standing or continuously flowing bodies of water with a 
continuous surface connection to a paragraph (a)(1) water or tributary 
that is relatively permanent. Waters assessed under paragraph (a)(5) 
meet the significant nexus standard if they ``significantly affect'' 
the chemical, physical, or biological integrity of a paragraph (a)(1) 
water.
    The agencies will generally assess jurisdiction over aquatic 
resources based on the requirements in paragraphs (a)(1) through (4) 
under this rule before assessing jurisdiction over aquatic resources 
based on paragraph (a)(5). Examples of aquatic resources that could be 
assessed for jurisdiction under paragraph (a)(5) include a stream that 
does not meet the agencies' interpretation of a tributary because it 
does not contribute flow directly or indirectly to a paragraph (a)(1) 
water or a paragraph (a)(2) impoundment; a wetland that does not meet 
this rule's definition of ``adjacent''; or a lake or pond that does not 
meet the agencies' interpretation of a tributary because it is not 
connected to the tributary network. A ditch that does not meet the 
agencies' interpretation of tributary could also be assessed for 
jurisdiction under paragraph (a)(5), so long as the ditch does not meet 
the terms of the paragraph (b)(3) exclusion. The preamble to the 
proposed rule stated that consistent with previous practice, the 
agencies would not assess whether a ditch was jurisdictional under the 
paragraph (a)(3) ``other waters'' provision. 86 FR 69433 (December 7, 
2021). However, the agencies have reconsidered this statement and 
determined that under previous practice, the agencies did in fact 
assess whether ditches were jurisdictional under the paragraph (a)(3) 
``other waters'' provision, and the agencies will continue to assess 
ditches that are not excluded under paragraph (b)(3) under the relevant 
jurisdictional categories in this final rule. The following sections of 
the preamble cover how to identify waters assessed under paragraph 
(a)(5) on the landscape, implementation of the relatively permanent 
standard for waters assessed under paragraph (a)(5), and implementation 
of the significant nexus

[[Page 3102]]

standard for waters assessed under paragraph (a)(5).
i. Identifying Waters Assessed Under Paragraph (a)(5) on the Landscape
    Under this rule, waters that will be assessed for jurisdiction 
under paragraph (a)(5) are: intrastate lakes and ponds, streams, and 
wetlands that do not meet the requirements to be considered under 
paragraphs (a)(1) through (4) of this rule. The agencies will identify 
waters assessed under paragraph (a)(5) on the landscape using the 
implementation tools that have previously been described for these 
aquatic resources (see sections IV.C.4 and IV.C.5 of this preamble). 
The agencies can draw upon a variety of remote- and field-based 
methods, including a variety of mapping resources for identifying 
aquatic resources.
ii. Implementing the Relatively Permanent Standard for Waters Assessed 
Under Paragraph (a)(5)
    Waters assessed under paragraph (a)(5) meet the relatively 
permanent standard if they are relatively permanent, standing or 
continuously flowing bodies of water with a continuous surface 
connection to a paragraph (a)(1) water or a tributary that is 
relatively permanent. The agencies have decided to implement this 
approach consistent with the Rapanos plurality opinion, and it reflects 
and accommodates regional differences in hydrology and water management 
and can be implemented using available, easily accessible tools. See 
sections IV.C.4.c and IV.C.5.c of this preamble.
    The agencies intend to identify relatively permanent waters under 
paragraph (a)(5) using a similar approach to the one described for 
relatively permanent tributaries in section IV.C.4.c.ii of this 
preamble. In summary, relatively permanent waters under paragraph 
(a)(5) include surface waters that have flowing or standing water year-
round or continuously during certain times of the year. Relatively 
permanent waters under paragraph (a)(5) include certain rivers and 
streams that have ``flowing water.'' The phrase ``standing water'' is 
intended to describe waters that are lentic or ``still'' systems, such 
as lakes, ponds, and impoundments, which are characterized by standing 
water and do not have a flowing outlet to the tributary system. In the 
context of waters assessed under paragraph (a)(5), the phrase 
``standing water'' can also describe certain wetlands that are 
characterized by standing water (e.g., many swamps). Relatively 
permanent waters under paragraph (a)(5) do not include features with 
flowing or standing water for only a short duration in direct response 
to precipitation. These features may include, for example, certain 
wetlands that are not characterized by standing water (e.g., many 
pocosin wetlands). See section IV.C.4.c.ii of this preamble for a 
description of implementation tools that can be used to identify 
relatively permanent waters under paragraph (a)(5).
    The agencies intend to identify a continuous surface connection 
between waters assessed under paragraph (a)(5) and a paragraph (a)(1) 
water or a tributary that is relatively permanent using the approach 
described for adjacent wetlands in section IV.C.5.c of this preamble 
(although waters assessed under paragraph (a)(5) are not subject to the 
adjacency requirement for jurisdictional adjacent wetlands). In 
summary, there must be a continuous surface connection on the landscape 
for waters assessed under paragraph (a)(5) to be jurisdictional under 
the relatively permanent standard. However, a continuous surface 
connection does not require a constant hydrologic connection. Waters 
assessed under paragraph (a)(5) can meet the continuous surface 
connection requirement if they are connected to a paragraph (a)(1) 
water or a tributary that is relatively permanent by a discrete feature 
like a non-jurisdictional ditch, swale, pipe, or culvert. Similarly, a 
natural berm, bank, dune, or similar natural landform between a water 
assessed under paragraph (a)(5) and a paragraph (a)(1) water or a 
tributary that is relatively permanent does not sever a continuous 
surface connection to the extent it provides evidence of a continuous 
surface connection. See section IV.C.5.c of this preamble for a 
description of implementation tools that can be used to assess a 
continuous surface connection for a water assessed under paragraph 
(a)(5).
    Under this rule, certain aquatic resources that do not meet the 
jurisdictional requirements for tributaries or adjacent wetlands could 
be jurisdictional as paragraph (a)(5) waters under the relatively 
permanent standard. For example, lakes and ponds that are not connected 
to a tributary system but are relatively permanent waters and have a 
continuous surface connection to a paragraph (a)(1) water or a 
tributary that is relatively permanent, could be jurisdictional as 
paragraph (a)(5) waters. To illustrate, a relatively permanent lake 
that is located near a tributary that meets the relatively permanent 
standard, but is separated by a natural berm, to the extent the berm 
provides evidence of a continuous surface connection, is jurisdictional 
as a paragraph (a)(5) water under the relatively permanent standard. 
See section IV.C.4.c.ii of this preamble. Similarly, a relatively 
permanent oxbow pond located near a traditional navigable water and 
connected to that traditional navigable water via a swale that provides 
a continuous surface connection between the pond and the traditional 
navigable water is jurisdictional as a paragraph (a)(5) water under the 
relatively permanent standard.
iii. Implementing the Significant Nexus Standard for Waters Assessed 
Under Paragraph (a)(5)
    Waters assessed under paragraph (a)(5) that do not meet the 
relatively permanent standard may be found jurisdictional under the 
significant nexus standard. Waters assessed under paragraph (a)(5) meet 
the significant nexus standard if they significantly affect the 
chemical, physical, or biological integrity of a traditional navigable 
water, the territorial seas, or an interstate water. Examples of waters 
assessed under paragraph (a)(5) include familiar types of waters like 
lakes and ponds, streams, and wetlands that have been the subject of 
significant nexus analyses under the tributaries and adjacent wetlands 
provisions of the pre-2015 regulations since the Rapanos Guidance was 
issued. See section IV.C.9 of this preamble for additional discussion 
on the definition of ``significantly affect'' in this rule, including 
the factors that will be considered and the functions that will be 
assessed as part of a significant nexus analysis. Consistent with 
longstanding practice, the agencies will assess these waters based on 
best professional judgment informed by the best available information.
    In implementing the significant nexus standard, the agencies 
generally intend to analyze waters under paragraph (a)(5) individually 
to determine if they significantly affect the chemical, physical, or 
biological integrity of a paragraph (a)(1) water. This approach 
reflects the agencies' consideration of public comments, as well as 
implementation considerations for waters assessed under paragraph 
(a)(5). While the agencies' regulations have long authorized the 
assertion of jurisdiction on a case-specific basis over waters that do 
not fall within the other jurisdictional provisions, since SWANCC and 
the issuance of the SWANCC Guidance with its requirement of 
headquarters approval over determinations under that

[[Page 3103]]

provision, the agencies have not in practice asserted jurisdiction over 
paragraph (a)(3) ``other waters'' under the pre-2015 regulatory 
regime.\111\
---------------------------------------------------------------------------

    \111\ Note that when the 2015 Clean Water Rule was in effect, 
the agencies did assert jurisdiction over waters that would have 
been known as paragraph (a)(3) ``other waters'' by rule if they were 
adjacent waters as defined by that rule and on a case-specific basis 
if they fell within the provisions requiring case-specific 
significant nexus determinations. The 2020 NWPR also asserted 
jurisdiction over certain lakes and ponds that would have been 
jurisdictional as paragraph (a)(3) ``other waters.''
---------------------------------------------------------------------------

    Some commenters specifically addressed implementation of the 
significant nexus standard for waters that do not fall within one of 
the more specific categories, with commenters supporting and opposing 
aggregation of such waters as part of a significant nexus analysis. 
Commenters opposing aggregation requested that the agencies assess 
water features individually to determine their significance to 
chemical, physical, or biological integrity of downstream paragraph 
(a)(1) waters. Commenters supporting aggregation of waters that do not 
fall within one of the more specific categories stated that such an 
approach was consistent with Rapanos and the science. The agencies 
addressed such waters individually on a case-by-case basis under pre-
2015 practice and have concluded at this time that individual 
assessments are practical and implementable for significant nexus 
determinations for waters assessed under paragraph (a)(5).
iv. Joint Agency Coordination on Waters Assessed Under Paragraph (a)(5)
    As is typical after a rule is promulgated, the agencies have 
entered into an agreement via a joint agency coordination memorandum to 
ensure the consistency and thoroughness of the agencies' implementation 
of this rule. As part of these coordination procedures, EPA and Corps 
field staff will coordinate on all draft approved jurisdictional 
determinations \112\ based on the significant nexus standard, and the 
agencies will follow a process for elevating a subset of these 
determinations to headquarters for review as necessary. That 
coordination will be enhanced for waters assessed under paragraph 
(a)(5) to ensure this provision is carefully implemented and to gather 
more robust data about the number and types of waters assessed under 
paragraph (a)(5) by the agencies, any regional or geographic issues, 
and the information and implementation resources needed to complete 
approved jurisdictional determinations for this category. As part of 
these coordination procedures, headquarters at the agencies will review 
all draft approved jurisdictional determinations for waters assessed 
under paragraph (a)(5) based on the significant nexus standard. The 
agencies do not intend for this coordination to result in the exclusion 
of paragraph (a)(5) waters that meet the significant nexus standard and 
are thus jurisdictional under this rule, but rather to serve as an 
additional check as to whether one of the jurisdictional standards is 
met. In addition, the agencies have established timelines for the 
review of certain draft approved jurisdictional determinations to 
ensure that there will not be unnecessary delay. Moreover, the 
coordination will enable the agencies to quickly address any potential 
inconsistencies, and that will enhance the efficiency of the approved 
jurisdictional determination process under this rule. Finally, after 
the memorandum is in effect for nine months, the agencies will 
reevaluate this requirement and assess the implementation and 
coordination approach, including assessing the scope and need for the 
coordination process.
---------------------------------------------------------------------------

    \112\ An approved jurisdictional determination is ``a Corps 
document stating the presence or absence of waters of the United 
States on a parcel or a written statement and map identifying the 
limits of waters of the United States on a parcel.'' 33 CFR 331.2.
---------------------------------------------------------------------------

7. Exclusions
    The agencies are including in the final rule regulatory text 
several exclusions from the definition of ``waters of the United 
States,'' including longstanding exclusions for prior converted 
cropland and waste treatment systems, and exclusions for features that 
were generally considered non-jurisdictional under the pre-2015 
regulatory regime. The regulatory text for this rule excludes the 
following features:
     waste treatment systems, including treatment ponds or 
lagoons, designed to meet the requirements of the Clean Water Act;
     prior converted cropland;
     ditches (including roadside ditches) excavated wholly in 
and draining only dry land and that do not carry a relatively permanent 
flow of water;
     artificially irrigated areas that would revert to dry land 
if the irrigation ceased;
     artificial lakes or ponds created by excavating or diking 
dry land to collect and retain water and which are used exclusively for 
such purposes as stock watering, irrigation, settling basins, or rice 
growing;
     artificial reflecting or swimming pools or other small 
ornamental bodies of water created by excavating or diking dry land to 
retain water for primarily aesthetic reasons;
     waterfilled depressions created in dry land incidental to 
construction activity and pits excavated in dry land for the purpose of 
obtaining fill, sand, or gravel unless and until the construction or 
excavation operation is abandoned and the resulting body of water meets 
the definition of waters of the United States; and
     swales and erosional features (e.g., gullies, small 
washes) characterized by low volume, infrequent, or short duration 
flow.
    These features were excluded by regulation or general practice 
under the pre-2015 regulatory regime and each of the subsequent rules 
defining ``waters of the United States.'' These exclusions from the 
definition provide important clarity on which features are and are not 
jurisdictional. As described in more detail below, to provide further 
clarity and certainty to the public, the agencies are codifying 
exclusions in the regulatory text for the features described in the 
proposed rule preamble as generally non-jurisdictional. Note that the 
word ``features'' when used in section IV.C.7 of this preamble refers 
broadly to landscape elements that may be evaluated in a determination 
of jurisdiction, e.g., streams, ponds, swales, wetlands, and 
depressions.
    The agencies are listing these exclusions in the regulatory text in 
a new paragraph (b) which consolidates the exclusions together in a 
single regulatory section. With this change, the regulatory text now 
identifies jurisdictional waters in paragraph (a), exclusions in 
paragraph (b), and definitions in paragraph (c). This change is 
consistent with the 2015 Clean Water Rule and 2020 NWPR, which both 
organized the regulatory text into these three paragraphs. This 
organizational structure clearly delineates waters that are 
jurisdictional from those waters and features that are excluded and 
provides a familiar and clear framework for the regulations. This 
reorganization does not affect the substance of the definition of 
``waters of the United States.''
    As explained in this rule's regulatory text, where a feature 
satisfies the terms of an exclusion, it is excluded from jurisdiction 
even where the feature would otherwise be jurisdictional under any of 
paragraphs (a)(2) through (5) of this rule. In such an instance, the 
feature is not considered ``waters of the United States.'' However, 
where a feature satisfies the terms of an exclusion but would otherwise 
be jurisdictional under paragraph (a)(1) of

[[Page 3104]]

this rule, the feature is not excluded.\113\ For example, where 
applicable, the exclusion in this rule for ditches excludes a ditch 
that is excavated wholly in dry land, drains only dry land, and does 
not carry a relatively permanent flow of water. However, all tidally-
influenced ditches are jurisdictional under paragraph (a)(1)(i) of the 
rule because they are ``subject to the ebb and flow of the tide,'' and 
therefore the exclusion is not applicable to those ditches. In 
addition, if a ditch was excavated in dry land very close to a 
territorial sea and, over time due to erosion, sea level rise, or other 
factors, the ditch develops a hydrologic connection to the territorial 
sea and becomes tidally-influenced, the ditch would then be considered 
jurisdictional under paragraph (a)(1) of this rule and would no longer 
be excluded. This is consistent with the agencies' longstanding 
position that a feature is not excluded where it would otherwise be 
jurisdictional as a traditional navigable water, territorial sea, or 
interstate water. See 51 FR 41217 (November 13, 1986) (explaining that 
``[n]on-tidal drainage and irrigation ditches excavated on dry land'' 
are generally not considered ``waters of the United States'' under the 
1986 regulations but not including similar language for tidally-
influenced ditches). The Clean Water Act fundamentally protects these 
three categories of waters: traditional navigable waters are clearly 
encompassed within the defined term ``navigable waters''; the 
territorial seas are explicitly mentioned in the statutory definition 
of ``navigable waters''; and, as discussed further in section 
IV.C.2.b.iii of this preamble, interstate waters are, by definition, 
waters of the ``several States'' and are unambiguously ``waters of the 
United States.'' While the agencies have authority to draw lines 
excluding some aquatic features from the definition of ``waters of the 
United States,'' the Clean Water Act provides no such authority to the 
agencies to exclude waters in these three unambiguous types of ``waters 
of the United States'' under the statute. Even if jurisdiction over one 
or all of these categories of waters were ambiguous, the agencies have 
concluded that since these are the fundamental waters that Congress 
intended to protect under the Clean Water Act, and that have had 
longstanding and unequivocal protection, with the exception of the 2020 
NWPR, it is reasonable to establish unequivocal jurisdiction over these 
waters. Further, the agencies have concluded that there are not policy, 
practical, or technical bases to apply the exclusions to these 
paragraph (a)(1) waters given their crucial role in the statutory 
regime. The agencies recognize that the 2020 NWPR allowed certain 
traditional navigable waters and the territorial seas to be excluded 
from jurisdiction if they satisfied the terms of certain exclusions. 
The 2020 NWPR did not provide a rationale for this aspect of the final 
rule. The agencies are restoring historic practice and, consistent with 
the Clean Water Act and as discussed above, are ensuring the protection 
of all paragraph (a)(1) waters in this rule.
---------------------------------------------------------------------------

    \113\ See also discussion of the waste treatment system 
exclusion in section IV.C.7.b of this preamble, infra.
---------------------------------------------------------------------------

    The exclusions reflect the agencies' longstanding practice and 
technical judgment that certain waters and features are not subject to 
the Clean Water Act. The exclusions are also guided by Supreme Court 
precedent. The plurality opinion in Rapanos noted that there were 
certain features that were not primarily the focus of the Clean Water 
Act. See 547 U.S. at 734. In this section of the rule, the agencies are 
promoting regulatory certainty by expressly stating that certain waters 
and features are not subject to jurisdiction under the Clean Water Act. 
Based on decades of implementation experience, the agencies have 
determined that waters that satisfy the terms of an exclusion are not 
``waters of the United States.'' Clearly identifying these exclusions 
in this rule is an important aspect of the agencies' policy goal of 
providing clarity and certainty. The categorical exclusions in this 
rule will simplify the process of determining jurisdiction, and they 
reflect the agencies' determinations of the lines of jurisdiction based 
on case law, policy determinations, and the agencies' experience and 
expertise.
    In addition, even when the features described below are not 
``waters of the United States'' because they are excluded (e.g., 
certain ditches, swales, gullies, erosional features), these and other 
non-jurisdictional features may be relevant to the analysis of whether 
another water meets the final rule's definition of ``waters of the 
United States.'' For example, consistent with longstanding practice, 
excluded surface features may still contribute to a hydrologic 
connection relevant for asserting jurisdiction (e.g., between an 
adjacent wetland and a jurisdictional water). See section IV.C.5 of 
this preamble; Rapanos Guidance at 12. Discharges to these non-
jurisdictional features may also be subject to certain Clean Water Act 
regulations. For example, a discharge from a point source to a non-
jurisdictional ditch that connects to a jurisdictional water may 
require a Clean Water Act section 402 permit. See Rapanos Guidance at 
12. In addition, non-jurisdictional ditches may themselves function as 
point sources (i.e., ``discernible, confined, and discrete 
conveyances''), such that discharges of pollutants from these features 
could require a Clean Water Act permit. See also Rapanos, 547 U.S. at 
743-44. While not the focus of this section, subsurface features that 
are non-jurisdictional may also be relevant to assessing jurisdiction 
of water features. See sections IV.C.4 and IV.C.5 of this preamble.
    Several commenters requested that the agencies exclude features 
from the definition of ``waters of the United States'' beyond those 
longstanding exclusions and historically non-jurisdictional features 
identified in the proposed rule. For example, several commenters 
requested that the agencies exclude stormwater control features, 
wastewater and drinking water treatment systems, and water recycling 
structures from the definition of ``waters of the United States.'' The 
agencies are not excluding these or other additional features in this 
rule. The proposed additional exclusions would not achieve the 
agencies' goal of maintaining consistency with the pre-2015 regulatory 
regime while continuing to advance the objective of the Clean Water 
Act. This approach is consistent with the agencies' intent in this rule 
to interpret ``waters of the United States'' to mean the waters defined 
by the longstanding 1986 regulations, with amendments to reflect the 
agencies' interpretation of the statutory limits on the scope of the 
``waters of the United States,'' informed by the text of the relevant 
provisions of the Clean Water Act and the statute as a whole, the 
scientific record, relevant Supreme Court case law, and the agencies' 
experience and technical expertise, in addition to consideration of 
extensive public comment on the proposed rule. However, even for 
features that are not explicitly excluded, the agencies will continue 
to assess jurisdiction under this rule on a case-specific basis. As 
part of this case-specific assessment, the agencies will continue to 
consider whether the feature in question is excavated or created in dry 
land, the flow of water in the feature, and other factors. In addition, 
some of the features that commenters asked the agencies to exclude may 
already be covered by one or more of the exclusions the agencies are 
including in this rule. For example, certain features that convey 
stormwater may be excluded as ditches under this

[[Page 3105]]

rule. Similarly, some of the features that commenters mentioned, like 
sheetflow, are not waters at all and would not be considered ``waters 
of the United States.'' Even though certain features may not be 
explicitly excluded, the agencies will not assert Clean Water Act 
jurisdiction over features that do not satisfy the definition of 
``waters of the United States'' articulated in paragraph (a) of this 
rule.
    Several commenters requested that the agencies explicitly exclude 
groundwater in this rule's regulatory text while other commenters 
requested that the agencies not exclude groundwater from jurisdiction 
under this rule. In this rule, the agencies are not adding an exclusion 
for groundwater to the regulatory text because groundwater is not 
surface water and therefore does not fall within the possible scope of 
``navigable waters.'' There is thus no need for a regulatory exclusion. 
This position is longstanding and consistent with Supreme Court case 
law. The agencies have never taken the position that groundwater falls 
within the scope of ``navigable waters'' under the Clean Water Act. 
See, e.g., 80 FR 37099-37100 (June 29, 2015) (explaining that the 
agencies have never interpreted ``waters of the United States'' to 
include groundwater); 85 FR 22278 (April 21, 2020) (explaining that the 
agencies have never interpreted ``waters of the United States'' to 
include groundwater). This position was recently confirmed by the U.S. 
Supreme Court. Maui, 140 S. Ct. at 1472 (``The upshot is that Congress 
was fully aware of the need to address groundwater pollution, but it 
satisfied that need through a variety of state-specific controls. 
Congress left general groundwater regulatory authority to the States; 
its failure to include groundwater in the general EPA permitting 
provision was deliberate.''). While groundwater itself is not 
jurisdictional as ``waters of the United States,'' discharges of 
pollutants to groundwater that reach a jurisdictional surface water 
require a NPDES permit where the discharge through groundwater is the 
``functional equivalent'' of a direct discharge from the point source 
into navigable waters. Maui, 140 S. Ct. at 1468. Groundwater that is 
not jurisdictional includes both shallow and deep groundwater, even 
where such shallow subsurface water serves as a hydrologic connection 
that is assessed in determining if another water is jurisdictional. 
Groundwater drained through subsurface drainage systems also is not 
jurisdictional. When groundwater emerges on the surface, for example 
when it becomes baseflow in streams or joins spring fed ponds, it is no 
longer considered to be groundwater under this rule.
    While groundwater is not jurisdictional under the statute or this 
rule, many States include groundwater in their definitions of ``waters 
of the State'' and therefore may subject groundwater to State 
regulation. Indeed, the Clean Water Act incentivizes State protection 
of groundwater. For example, grants to States under Clean Water Act 
section 319 may support management programs that include groundwater 
quality protection activities as part of a comprehensive nonpoint 
source pollution control program. 33 U.S.C. 1329(h)(5)(D). In addition, 
groundwater quality is regulated and protected through several other 
legal mechanisms, including the Safe Drinking Water Act, the Resource 
Conservation and Recovery Act, and various Tribal, State, and local 
laws.
    Several commenters suggested that wetlands that develop entirely 
within the confines of a non-jurisdictional feature should be 
considered part of the excluded feature and not be considered ``waters 
of the United States.'' The agencies agree with these commenters and 
find that wetlands that develop entirely within the confines of an 
excluded feature are not jurisdictional. This interpretation is 
consistent with the agencies' longstanding approach to this issue and 
with the agencies' rationale for excluding these features. This 
approach also provides environmental benefits because it removes the 
incentive for parties to clear vegetation from an excluded feature to 
prevent that vegetation from developing into a wetland and becoming 
jurisdictional, thus allowing vegetation within the confines of an 
excluded feature to provide water quality benefits for the duration of 
its existence.
    However, a wetland may be located both within and outside the 
boundaries of a non-jurisdictional feature or entirely outside the 
boundaries of non-jurisdictional feature. In these circumstances, the 
wetland will be evaluated under this rule's provisions for ``adjacent 
wetlands'' and paragraph (a)(5) ``intrastate lakes and ponds, streams, 
or wetlands'' and not considered as part of the non-jurisdictional 
feature. It is important to note, however, that although some low 
gradient depressional areas are colloquially referred to as ``swales,'' 
these areas do not meet the regulatory exclusion's criteria for swales 
that are discrete topographic features ``characterized by low volume, 
infrequent, or short duration flow.'' As such, the agencies would not 
consider wetlands forming within low gradient depressional areas to be 
``within the confines of a non-jurisdictional feature,'' and such 
wetlands would be assessed to determine if they meet any of the 
provisions of this rule.
    While the agencies evaluate whether any exclusions apply when 
making approved jurisdictional determinations for purposes of 
efficiency, the person asserting that the water at issue is excluded 
under the Clean Water Act or that the person's activities at issue in 
the case are exempt under the Act, may have information that is 
material to proving that the exclusion or exemption applies. There are 
circumstances where, absent this information from the requestor, the 
agency will be unable to determine that an exclusion applies. While the 
requestor is not required to provide information regarding 
applicability of the exclusions to the agencies during the 
jurisdictional determination process, it is to their benefit to do so 
because the person asserting that a water is excluded or that a 
person's activities are exempt under the Clean Water Act bears the 
burden of proving that the exclusion or exemption applies. See, e.g., 
United States v. Akers, 785 F.2d 814, 819 (9th Cir. 1986) (``Akers must 
establish that his activities are exempt.''). Where the agencies, based 
on the information that they have in the record, are unable to conclude 
that an exclusion applies, the agencies will assess the water to see if 
it meets the jurisdictional criteria of this rule under paragraphs 
(a)(1) through (5).
a. Prior Converted Cropland
i. This Rule
    This rule repromulgates the regulatory exclusion for prior 
converted cropland first codified in 1993, which provided that prior 
converted cropland is ``not `waters of the United States.''' This rule 
restores longstanding and familiar practice under the pre-2015 
regulatory regime. The rule maintains consistency and compatibility 
between the agencies' implementation of the Clean Water Act and the 
U.S. Department of Agriculture's (USDA) implementation of the Food 
Security Act by providing that prior converted cropland under the Clean 
Water Act encompasses areas designated by USDA as prior converted 
cropland. Areas USDA has not so designated are not eligible for this 
Clean Water Act exclusion. The Clean Water Act exclusion for prior 
converted cropland only covers wetlands and does not exclude other 
types of non-wetland aquatic resources (e.g., tributaries,

[[Page 3106]]

ponds, ditches) that are located within the prior converted cropland 
area.
    The exclusion would cease upon a change in use that renders the 
area no longer available for the production of agricultural 
commodities. For example, areas used for any agricultural purposes, 
including agroforestry, as well as areas left idle, generally remain 
available for the production of agricultural commodities. In response 
to requests from commenters to increase the clarity of the exclusions 
through the regulatory text, the agencies are noting in the regulations 
that this exclusion encompasses areas that USDA has designated as prior 
converted cropland, and that the exclusion will cease when the area has 
changed use so that it is no longer available for the production of 
agricultural commodities, such as when it has been filled for 
development.
    The agencies are also retaining the longstanding provision that 
``for purposes of the Clean Water Act, the final authority regarding 
Clean Water Act jurisdiction remains with EPA.'' This categorical 
exclusion for prior converted cropland will simplify the process of 
determining jurisdiction while providing certainty to farmers seeking 
to conserve and protect land and waters pursuant to Federal law. It 
reflects the agencies' determinations of the lines of jurisdiction 
based on the case law, policy determinations, and the agencies' 
experience and expertise.
ii. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    The concept of prior converted cropland originates in the wetland 
conservation provisions of the Food Security Act of 1985, 16 U.S.C. 
3801 et seq. These provisions were intended to disincentivize the 
conversion of wetlands to croplands. Under the Food Security Act 
wetland conservation provisions, farmers who convert wetlands to make 
possible the production of an agricultural commodity crop may lose 
eligibility for certain USDA program benefits, unless an exemption 
applies. If a farmer had converted wetlands to cropland prior to 
December 23, 1985, however, then the land is considered prior converted 
cropland and the farmer does not lose eligibility for benefits if the 
area is further manipulated.\114\ USDA defines a prior converted 
cropland for Food Security Act purposes in its regulations as 
``converted wetland where the conversion occurred prior to December 23, 
1985, an agricultural commodity had been produced at least once before 
December 23, 1985, and as of December 23, 1985, the converted wetland 
did not support woody vegetation and did not meet the hydrologic 
criteria for farmed wetland.'' 7 CFR 12.2. USDA defines an agricultural 
commodity, in turn, as ``any crop planted and produced by annual 
tilling of the soil, including tilling by one-trip planters, or 
sugarcane.'' Id. at 12.2; see also 16 U.S.C. 3801(a)(1).
---------------------------------------------------------------------------

    \114\ A farmer that ``commenced conversion'' of a wetland prior 
to December 23, 1985, could also be eligible for a prior converted 
cropland designation, subject to certain limitations. 7 CFR 12.2, 
12.5(b)(2).
---------------------------------------------------------------------------

    In 1993, EPA and the Corps codified an exclusion for prior 
converted cropland from the definition of ``waters of the United 
States'' regulated pursuant to the Clean Water Act. The exclusion 
stated, ``[w]aters of the United States do not include 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.'' 58 FR 45008, 45036 (August 25, 1993); 
33 CFR 328.3(a)(8) (1994); 40 CFR 230.3(s) (1994). The 1993 preamble 
stated that EPA and the Corps would interpret the prior converted 
cropland exclusion consistent with the definition in the National Food 
Security Act Manual (NFSAM) published by the USDA Soil Conservation 
Service, now known as USDA's Natural Resource Conservation Service 
(NRCS). 58 FR 45031 (August 25, 1993). It cited the NFSAM definition of 
prior converted cropland as ``areas that, prior to December 23, 1985, 
were drained or otherwise manipulated for the purpose, or having the 
effect, of making production of a commodity crop possible. [Prior 
converted] cropland is inundated for no more than 14 consecutive days 
during the growing season and excludes pothole or playa wetlands.'' Id. 
The agencies chose not to codify USDA's definition of prior converted 
cropland, ensuring that they would retain flexibility to accommodate 
changes USDA might make. Id. at 45033.
    The purpose of the exclusion, as EPA and the Corps explained in the 
1993 preamble, was to ``codify existing policy,'' as the agencies had 
not been implementing the Clean Water Act to regulate prior converted 
cropland, and to ``help achieve consistency among various federal 
programs affecting wetlands.'' Id. The 1993 preamble further stated 
that excluding prior converted cropland from ``waters of the United 
States'' was consistent with protecting aquatic resources because 
``[prior converted cropland] has been significantly modified so that it 
no longer exhibits its natural hydrology or vegetation. . . . [Prior 
converted] cropland has therefore been significantly degraded through 
human activity and, for this reason, such areas are not treated as 
wetlands under the Food Security Act.'' Id. at 45032. The agencies 
explained that ``in light of the degraded nature of these areas, we do 
not believe that they should be treated as wetlands for the purposes of 
the CWA.'' Id.
    The 1993 preamble stated that, consistent with the NFSAM, an area 
would lose its status as prior converted cropland if the cropland is 
``abandoned,'' meaning that crop production ceases and the area reverts 
to a wetland state. Id. at 45034. Specifically, the 1993 preamble 
stated that prior converted cropland that now meets wetland criteria 
will be considered abandoned unless ``once in every five years it has 
been used for the production of an agricultural commodity, or the area 
has been used and will continue to be used for the production of an 
agricultural commodity in a commonly used rotation with aquaculture, 
grasses, legumes, or pasture production.'' Id. at 45034.
    Three years later, the Federal Agriculture Improvement and Reform 
Act of 1996 amended the Food Security Act and clarified that this 
``abandonment'' principle did not apply to prior converted cropland. 
See Public Law 104-127, 110 Stat. 988-89 (1996). Additional amendments 
clarified that any certification by the Secretary, including those of 
prior converted cropland, remain valid and in effect as long as it 
continues to be available for agricultural purposes, a new approach 
referred to as ``change in use.'' H.R. Conf. Rep. No. 104-494, at 380 
(1996). EPA and the Corps did not address the 1996 amendments in 
rulemaking. In 2005, the Corps and NRCS issued a joint Memorandum to 
the Field in an effort to again align the Clean Water Act section 404 
program with the Food Security Act by adopting the principle that a 
wetland can lose prior converted cropland status following a ``change 
in use.'' The Memorandum stated, ``[a] certified [prior converted] 
determination made by NRCS remains valid as long as the area is devoted 
to an agricultural use. If the land changes to a non-agricultural use, 
the [prior converted] determination is no longer applicable and a new 
wetland determination is required for CWA purposes.'' It defined 
``agricultural use'' as ``open land planted to an agricultural crop, 
used for the production of food or fiber, used for haying or grazing, 
left idle per USDA

[[Page 3107]]

programs, or diverted from crop production to an approved cultural 
practice that prevents erosion or other degradation.'' The agencies 
rescinded the 2005 Memorandum on January 28, 2021, following 
publication of the 2020 NWPR.
    One district court set aside the Corps' adoption of ``change in 
use'' on the grounds that it was a substantive change in Clean Water 
Act implementation that the agencies had not issued through notice and 
comment rulemaking. New Hope Power Co. v. U.S. Army Corps of Eng'rs, 
746 F. Supp. 2d 1272, 1282 (S.D. Fla. 2010). Following New Hope Power, 
the agencies did not implement ``change in use'' in areas subject to 
the court's jurisdiction.
    The 2015 Clean Water Rule repromulgated the exclusion for prior 
converted cropland without any changes from the 1993 regulations, as 
did the 2019 Repeal Rule. The 2020 NWPR also repromulgated the 
exclusion but defined prior converted cropland for purposes of the 
Clean Water Act for the first time since 1993. The 2020 NWPR provided 
that an area is prior converted cropland if ``prior to December 23, 
1985, [it] was drained or otherwise manipulated for the purpose, or 
having the effect, of making production of an agricultural product 
possible.'' 85 FR 22339 (April 21, 2020); 33 CFR 328.3(c)(9). The 2020 
NWPR's term ``agricultural product'' potentially extended prior 
converted cropland status far beyond those areas USDA considers prior 
converted cropland for purposes of the Food Security Act. Specifically, 
USDA's regulation defining prior converted cropland refers to 
conversion that makes possible production of an ``agricultural 
commodity,'' a defined term, while the 2020 NWPR defined prior 
converted cropland to encompass any area used to produce an 
``agricultural product,'' a term not used in the regulations that 
introduced ambiguity and further distinguished the Clean Water Act's 
prior converted cropland exclusion from USDA's approach. Compare 7 CFR 
12.2 with 33 CFR 328.3(c)(9). The absence of a definition in the 2020 
NWPR for the term ``agricultural product'' or any explanation as to how 
it may differ from an ``agricultural commodity'' was unclear and 
undermined the original purpose of the exclusion, which was to help 
achieve consistency among Federal programs affecting wetlands. See 58 
FR 45031 (August 25, 1993).
    Furthermore, the 2020 NWPR's approach to prior converted cropland 
substantially reduced the likelihood that prior converted cropland 
would lose its excluded status because it provided that an area would 
remain prior converted cropland for purposes of the Clean Water Act 
unless the area is abandoned and reverts to wetlands, and defined 
abandonment to occur when prior converted cropland ``is not used for, 
or in support of, agricultural purposes at least once in the 
immediately preceding five years.'' 85 FR 22320 (April 21, 2020). The 
2020 NWPR then presented a broad interpretation of ``agricultural 
purposes,'' including but not limited to crop production, haying, 
grazing, idling land for conservation uses (such as habitat; pollinator 
and wildlife management; and water storage, supply, and flood 
management); irrigation tailwater storage; crawfish farming; cranberry 
bogs; nutrient retention; and idling land for soil recovery following 
natural disasters such as hurricanes and drought. Id. at 22321. Under 
the 2020 NWPR, prior converted cropland maintained its excluded status 
if it was used at least once in the five years preceding a 
jurisdictional determination for any of these agricultural purposes. 
These wetlands could then have been filled and paved over during that 
five-year term without triggering any Clean Water Act regulatory 
protection.
    This rule restores the exclusion's original purpose of maintaining 
consistency among Federal programs addressing wetlands while furthering 
the objective of the Clean Water Act. 58 FR 45031-32 (August 25, 1993). 
Some commenters asserted that prior converted cropland should not be 
categorically excluded because there is no legal or scientific basis to 
exclude areas from the protections of the Clean Water Act that maintain 
some wetland characteristics or could be restored to be wetlands. The 
agencies disagree. As the agencies explained in 1993, ``effective 
implementation of the wetlands provisions of the Act without unduly 
confusing the public and regulated community is vital to the 
environmental protection goals of the Clean Water Act.'' Id. at 45031. 
The 1993 preamble emphasized that statutes other than the Clean Water 
Act have become essential to the Federal Government's effort to protect 
wetlands. The wetlands protection effort will be most effective if the 
agencies administering these other statutes have, to the extent 
possible, ``consistent and compatible approaches to insuring wetlands 
protection.'' Id. at 45031-32. This rule's return to implementing 
USDA's approach to prior converted cropland will help enhance the 
consistency and compatibility of the Federal Government's multi-pronged 
wetlands protection efforts, thereby enhancing their effectiveness.
    Some commenters asked that the agencies codify a particular 
definition of prior converted cropland; some recommended codifying 
USDA's definition and others advocated codifying the definition in the 
2020 NWPR. The agencies instead decided to clarify that the exclusion 
encompasses prior converted cropland designated by USDA, and no 
additional areas. This clarification provides certainty and 
transparency as well as flexibility. The agencies chose not to codify 
the 2020 NWPR's definition because that interpretation does not carry 
out the original purpose of the exclusion, which is to ensure 
consistency among Federal wetland protection programs while protecting 
the integrity of the nation's waters.
iii. Implementation
    This rule will implement the prior converted cropland exclusion so 
that it encompasses all areas designated by USDA, and no additional 
areas. USDA interprets prior converted cropland to be a ``converted 
wetland where the conversion occurred prior to December 23, 1985, an 
agricultural commodity had been produced at least once before December 
23, 1985, and as of December 23, 1985, the converted wetland did not 
support woody vegetation and did not meet the hydrologic criteria for 
farmed wetland.'' 7 CFR 12.2. The 2020 NWPR introduced ambiguity by 
saying that prior converted cropland applies to certain areas used for 
``agricultural products,'' as opposed to ``agricultural commodities.'' 
In addition, the 2020 NWPR was unclear regarding the extent to which 
the agencies should designate areas not subject to a USDA designation 
as prior converted cropland under the Clean Water Act. The agencies are 
restoring clarity and consistency with USDA's approach by implementing 
the exclusion as only applying to areas USDA has designated, which 
include areas where commodity crops were produced prior to December 23, 
1985, and that meet the other applicable criteria. This is consistent 
with the agencies' longstanding approach to the exclusion. See 58 FR 
45033 (August 25, 1993) (``[R]ecognizing [NRCS]'s expertise in making 
these [prior converted] cropland determinations, we will continue to 
rely generally on determinations made by [NRCS].''). USDA defines 
agricultural commodity crops to mean ``any crop planted and produced by 
annual tilling of the soil, including tilling by one-trip planters, or 
sugarcane.'' 7 CFR 12.2.
    The agencies have also decided to enhance consistency between prior 
converted cropland under the Food

[[Page 3108]]

Security Act and under the Clean Water Act, without undermining the 
goals of the Clean Water Act, by implementing the exclusion as ceasing 
upon the area's ``change in use.'' The agencies view a ``change in 
use'' as an action that would make the prior converted cropland no 
longer available for the production of an agricultural commodity. In 
response to requests from commenters to clarify the scope of exclusions 
in the regulatory text, the regulation specifies that the exclusion 
will cease upon change in use, and that a change in use means that the 
prior converted cropland is no longer available for the production of 
an agricultural commodity.
    Consistent with USDA's interpretation, a ``change in use'' would 
not occur ``[a]s long as the area is devoted to the use and management 
of the land for production of food, fiber, or horticultural crops.'' 7 
CFR 12.30(c)(6). The agencies do not interpret changes in use to 
include discharges associated with agricultural uses identified in the 
Corps' and NRCS's 2005 Memorandum to the Field, such as planting of 
agricultural crops, production of food or fiber, haying or grazing, 
idling consistent with USDA programs, or diversion from crop production 
for purposes of preventing erosion or other degradation, as these uses 
keep the land available for future production of agricultural 
commodities. Similarly, an area may retain its prior converted cropland 
status if it is used for any of the agricultural purposes identified in 
the 2020 NWPR preamble, which ``includ[e] but [are] not limited to 
idling land for conservation uses (e.g., habitat; pollinator and 
wildlife management; and water storage, supply, and flood management); 
irrigation tailwater storage; crawfish farming; cranberry bogs; 
nutrient retention; and idling land for soil recovery following natural 
disasters like hurricanes and drought,'' as well as ``crop production, 
haying, and grazing,'' so long as the area remains available for the 
production of agricultural commodities. See 85 FR 22321 (April 21, 
2020). Consistent with USDA practice, an area has not experienced a 
change in use if, for example, it transitions into a long-term rotation 
to agroforestry or perennial crops, such as vineyards or orchards, or 
if it lies idle and the landowner passively preserves the area for 
wildlife use. Generally speaking, idling the land retains its 
availability for the production of an agricultural commodity. 
Implementing ``change in use'' consistent with USDA's implementation of 
the Food Security Act fulfills the exclusion's purpose of promoting 
consistency among Federal programs affecting wetlands. See 58 FR 45031 
(August 25, 1993). Under the Food Security Act, a wetland certification 
made by the Secretary is only valid so long as the area is devoted to 
an agricultural use. 16 U.S.C. 3822(a)(4). Because the wetland 
conservation provisions of the Food Security Act only apply to the 
production of agricultural commodities, a prior converted cropland 
designation becomes moot for USDA purposes once land is removed from 
agricultural use.
    A ``change in use'' is a proposed or planned modification of prior 
converted cropland for filling and development, so that the area would 
no longer be available for commodity crop production after development. 
For example, if prior converted cropland is left idle for several years 
and reverts to wetland, and the property is then sold for conversion to 
a residential development, the discharge of dredged or fill material 
from development would require prior authorization under Clean Water 
Act section 404. Plans or proposals for development may include 
applications for Clean Water Act section 404 permits or other Federal, 
State, or local permits for residential, commercial, or industrial 
development; energy infrastructure; mining; or other non-agricultural 
uses. On the one hand, the agencies recognize that plans and proposals 
do not themselves change the characteristics of a wetland, and that 
some do not come to fruition. On the other hand, the agencies would 
like to provide certainty and fair notice to landowners and other 
persons about the status of the areas under their control while they 
are in the planning stage. Interpreting a change in use as only 
occurring when heavy machinery begins actually dredging and filling a 
wetland, and potentially violating the Clean Water Act, would not 
provide the certainty and fair notice necessary to appropriately plan 
development. To address these considerations, the agencies will 
interpret the prior converted cropland designation to continue to apply 
to a farmer's use of prior converted cropland for agricultural purposes 
even after development plans or proposals have been developed, and even 
after land has been sold. However, the prior converted cropland 
designation would not be available to the developer for the same parcel 
once proposals or plans for development have begun, even prior to a 
discharge occurring in the wetland.
    Some commenters stated that, for example, building houses in an 
area should not constitute a ``change in use,'' because the houses 
could potentially be removed and the area returned to commodity crop 
production. The agencies disagree. A ``change in use'' includes areas 
that have undergone soil disturbance such that substantial effort, such 
as the removal of concrete or other permanent structures, would be 
required to enable the production of agricultural commodities. The 
agencies interpret availability for commodity crop production to mean 
that it is reasonably conceivable that the area in its current 
condition could be returned to crop production. Areas that will be 
developed for residential, commercial, or industrial use; energy 
infrastructure; mining; or other non-farming related activities will 
not meet this standard of availability for commodity crop production.
    The agencies will not implement the exclusion using the 
``abandonment'' approach, which the 2020 NWPR implemented instead of 
``change in use,'' as ``abandonment'' is not consistent with USDA's 
approach or with the purposes of the Clean Water Act. Generally 
speaking, under the 2020 NWPR's approach to abandonment, an area would 
only regain jurisdictional status if the area has not been used for 
agricultural purposes at least once in every five years and the area 
reverts to a wetland that meets the definition of ``waters of the 
United States.'' For example, under abandonment, if prior converted 
cropland is used for an agricultural purpose, such as grazing, two 
years prior to being sold for conversion to a residential development, 
discharges of dredged or fill material from the construction of the 
residential development into the wetlands during the three years 
remaining in the five-year abandonment time frame would not require 
authorization under Clean Water Act section 404, even though those 
discharges have nothing to do with farming. In contrast, under the 
``change in use'' approach that the agencies will implement under this 
rule, the reverted wetland area would regain jurisdictional status if 
it meets the definition of ``waters of the United States'' and is 
subject to a ``change in use,'' meaning that it is no longer available 
for production of an agricultural commodity.
    The abandonment approach implemented in the 2020 NWPR presents 
three key concerns. First, it incentivizes disturbance of the area by a 
farmer once every five years to retain the exclusion. Second, it 
creates a substantial loophole in Clean Water Act section 404 
protections by allowing any form of development of otherwise 
jurisdictional wetlands without

[[Page 3109]]

authorization, so long as it occurs within five years of use of the 
area for agricultural purposes. Third, it undermines governmental 
coordination and efficiency because it is not consistent with USDA's 
approach to prior converted cropland.
    A number of commenters urged the agencies to maintain the 2020 
NWPR's approach to implementing prior converted cropland, emphasizing 
that on a national scale, developing wetlands, such as for purposes of 
mining or other industrial uses, could provide billions of dollars to 
farmers. The agencies have concluded that this potential financial 
benefit to farmers does not effectuate the original purpose of the 
exclusion, which was to promote consistency among Federal clean water 
protection programs in order to help restore and maintain the nation's 
waters. Moreover, the exclusion was originally intended to allow 
farmers to farm their land. The financial benefit the commenters cite 
comes from selling farmland to be developed. Further facilitating these 
sales does nothing to support farmers who seek to continue to farm and 
could even undermine their incentives to do so. By contrast, the 
agencies' approach in this rule strikes an appropriate balance between 
effectuating the goals of the Clean Water Act and the purposes of the 
exclusion. It aligns implementation of the Food Security Act and the 
Clean Water Act as much as possible while providing farmers with 
clarity that routine farming and related activity conducted in prior 
converted croplands will not require Clean Water Act authorization.
    The agencies' approach to prior converted cropland under this rule 
also imposes less of a burden on farmers than the approach under the 
2020 NWPR. Under the 2020 NWPR, an area was not considered abandoned so 
long as it is used for or in support of agricultural purposes at least 
once in the immediately preceding five years. The 2020 NWPR's preamble 
explained that prior converted cropland would not be considered 
abandoned if it were idled or lay fallow ``for conservation or 
agricultural purposes.'' 85 FR 22320 (April 21, 2020). By contrast, 
under ``change in use,'' the land will not lose its prior converted 
cropland status so long as it remains available for crop production, 
regardless of whether the purpose for idling the land was related to 
conservation or agricultural purposes. In other words, under this rule, 
a farmer could maintain prior converted cropland status without needing 
to demonstrate that the area was used for in support of agricultural 
purposes at least once in the immediately preceding five years or had 
been idled for conservation or agricultural purposes.
    The exclusion for prior converted cropland does not apply to areas 
designated by USDA as meeting other Food Security Act exemptions, 
including exemptions for farmed wetlands, or areas that meet the USDA 
definition of wetlands and do not have a valid prior converted cropland 
designation. This rule would maintain the provision promulgated in 1993 
that EPA retains final authority to determine whether an area is 
subject to the requirements of the Clean Water Act. The presence of a 
jurisdictional wetland, or any jurisdictional water in an agricultural 
setting, in no way affects the availability of exemptions for 
discharges associated with many farming activities pursuant to Clean 
Water Act section 404(f).
b. Waste Treatment System
i. This Rule
    This rule in paragraph (b)(1) retains the agencies' longstanding 
waste treatment system exclusion, with no changes from the proposed 
rule. Specifically, this rule provides that ``[w]aste treatment 
systems, including treatment ponds or lagoons, designed to meet the 
requirements of the Clean Water Act'' are not ``waters of the United 
States.'' This language is the same as the agencies' 1986 regulation's 
waste treatment system exclusion,\115\ with a ministerial change to 
delete the exclusion's cross-reference to a definition of ``cooling 
ponds'' that no longer exists in the Code of Federal Regulations, and 
the addition of a comma that clarifies the agencies' longstanding 
implementation of the exclusion as applying only to systems that are 
designed to meet the requirements of the Act.
---------------------------------------------------------------------------

    \115\ 51 FR 41250 (November 13, 1986); 53 FR 20764 (June 6, 
1988).
---------------------------------------------------------------------------

ii. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    EPA first promulgated the waste treatment system exclusion in a 
1979 notice-and-comment rulemaking revising the definition of ``waters 
of the United States'' in the agency's NPDES regulations. 44 FR 32854 
(June 7, 1979). A ``frequently encountered comment'' was that ``waste 
treatment lagoons or other waste treatment systems should not be 
considered waters of the United States.'' Id. at 32858. EPA agreed, 
except as to cooling ponds that otherwise meet the criteria for 
``waters of the United States.'' Id. The 1979 revised definition of 
``waters of the United States'' thus provided that ``waste treatment 
systems (other than cooling ponds meeting the criteria of this 
paragraph) are not waters of the United States.'' Id. at 32901 (40 CFR 
122.3(t) (1979)).
    The following year, EPA revised the exclusion, but again only in 
its NPDES regulations, to clarify its application to treatment ponds 
and lagoons and to specify the type of cooling ponds that fall outside 
the scope of the exclusion. 45 FR 33290, 33298 (May 19, 1980). EPA also 
decided to revise this version of the exclusion to clarify that 
``treatment systems created in [waters of the United States] or from 
their impoundment remain waters of the United States,'' while 
``[m]anmade waste treatment systems are not waters of the United 
States.'' Id. The revised exclusion read: ``[w]aste treatment systems, 
including treatment ponds or lagoons designed to meet the requirements 
of CWA (other than cooling ponds as defined in 40 CFR 423.11(m) which 
also meet the criteria of this definition) are not waters of the United 
States.'' The provision further provided that the exclusion ``applies 
only to manmade bodies of water which neither were originally created 
in waters of the United States (such as a disposal area in wetlands) 
nor resulted from the impoundment of waters of the United States.'' 45 
FR 33424 (May 19, 1980) (40 CFR 122.3).
    Two months following this revision, EPA took action to ``suspend[ ] 
a portion'' of the waste treatment system exclusion in its NPDES 
regulations in response to concerns raised in petitions for review of 
the revised definition of ``waters of the United States.'' 45 FR 48620 
(July 21, 1980). EPA explained that industry petitioners objected to 
limiting the waste treatment system exclusion to manmade features, 
arguing that the revised exclusion ``would require them to obtain 
permits for discharges into existing waste treatment systems, such as 
power plant ash ponds, which had been in existence for many years.'' 
Id. at 48620. The petitioners argued that ``[i]n many cases, . . . EPA 
had issued permits for discharges from, not into, these systems.'' Id. 
Agreeing that the regulation ``may be overly broad'' and ``should be 
carefully reexamined,'' EPA announced that it was ``suspending [the] 
effectiveness'' of the sentence limiting the waste treatment system 
exclusion to manmade bodies of water. Id. EPA then stated that it 
``intend[ed] promptly to develop a revised definition and to publish it 
as a proposed rule for public comment,'' after which the agency would 
decide whether to ``amend the rule, or terminate the suspension.'' Id.

[[Page 3110]]

    In 1983, EPA republished the waste treatment system exclusion in 
its NPDES regulations with a note explaining that the agency's July 
1980 action had ``suspended until further notice'' the sentence 
limiting the exclusion to manmade bodies of water, and that the 1983 
action ``continue[d] that suspension.'' 48 FR 14146, 14157 (April 1, 
1983) (40 CFR 122.2) (1984). EPA subsequently omitted the exclusion's 
suspended sentence altogether in revising the definition of ``waters of 
the United States'' in other parts of the Code of Federal Regulations. 
See, e.g., 53 FR 20764, 20774 (June 6, 1988) (revising EPA's section 
404 program definitions at 40 CFR 232.2). Separately, the Corps 
published an updated definition of ``waters of the United States'' in 
1986. This definition contained the waste treatment system exclusion 
but likewise did not include the exclusion's suspended sentence: 
``Waste treatment systems, including treatment ponds or lagoons 
designed to meet the requirements of CWA (other than cooling ponds as 
defined in 40 CFR 123.11(m) which also meet the criteria of this 
definition) are not waters of the United States.'' 51 FR 41250 
(November 13, 1986); 33 CFR 328.3 (1987).
    Later revisions to the definition of cooling ponds rendered the 
exclusion's cross-reference to 40 CFR 123.11(m) outdated. See 47 FR 
52290, 52291, 52305 (November 19, 1982) (revising regulations related 
to cooling waste streams and deleting definition of cooling ponds). In 
this rule, the agencies have deleted this obsolete cross-reference, 
consistent with other recent rulemakings addressing the definition of 
``waters of the United States.'' \116\
---------------------------------------------------------------------------

    \116\ 85 FR 22250, 22325 (April 21, 2020) (``One ministerial 
change [to the waste treatment system exclusion] is the deletion of 
a cross-reference to a definition of `cooling ponds' that no longer 
exists in the Code of Federal Regulations.''); 80 FR 37054, 37097 
(June 29, 2015) (``One ministerial change [to the waste treatment 
system exclusion] is the deletion of a cross-reference in the 
current language to an EPA regulation that no longer exists.'').
---------------------------------------------------------------------------

    This rule also deletes the suspended sentence in EPA's NPDES 
regulations limiting application of the waste treatment system 
exclusion to manmade bodies of water. The suspended sentence, which 
since 1980 has only ever appeared in the version of the waste treatment 
system exclusion contained in EPA's NPDES regulations (40 CFR 122.2), 
provides: ``This exclusion applies only to manmade bodies of water 
which neither were originally created in waters of the United States 
(such as disposal area in wetlands) nor resulted from the impoundment 
of waters of the United States.'' Because EPA suspended this sentence 
limiting application of the exclusion in 1980, EPA has not limited 
application of the waste treatment system exclusion to manmade bodies 
of water for over four decades. Removing the suspended sentence in this 
rule thus aligns with EPA's decades-long practice implementing the 
exclusion--in addition to ensuring consistency with the text of other 
versions of the exclusion found in the agencies' regulations (both past 
and present)--and maintains the 2020 NWPR's deletion of the suspended 
sentence as well.
    Some commenters expressed support for deleting the suspended 
sentence, stating that doing so in this rule would be consistent with 
the agencies' longstanding approach to implementing the waste treatment 
system exclusion. Other commenters asserted that the agencies should 
limit application of the exclusion to human-made features, with some 
expressing concern that the agencies have not provided a meaningful 
opportunity to comment on this aspect of the rulemaking. The agencies 
agree that removing the suspended sentence--which has not been in 
effect for over 40 years--ensures that this rule will continue the 
agencies' longstanding approach to excluding waste treatment systems, 
while providing additional clarity. Indeed, for decades, both agencies 
have not limited application of the exclusion to manmade bodies of 
water. The agencies disagree that they did not satisfy notice-and-
comment requirements with respect to this aspect of the rulemaking. The 
preamble to the proposed rule explained that the agencies were 
considering deleting the suspended sentence and explicitly solicited 
comment on that approach. See 86 FR 69427.
    Multiple commenters expressed concern over the agencies' proposed 
addition of a comma after the word ``lagoons'' in the text of the 
exclusion, which provides: ``Waste treatment systems, including 
treatment ponds or lagoons, designed to meet the requirements of the 
Clean Water Act are not waters of the United States.'' In particular, 
many of these commenters asserted that the new comma would narrow the 
exclusion such that a system constructed prior to the enactment of the 
Clean Water Act could not qualify for the exclusion because it was not 
``designed'' to meet the requirements of the Act. As explained in the 
preamble to the proposed rule, the purpose of adding a comma after 
``lagoons'' is to clarify that the exclusion is available only to 
systems meeting the requirements of the Clean Water Act, thereby 
continuing the agencies' longstanding approach to implementing the 
exclusion. Under this approach, a waste treatment system constructed 
prior to the 1972 Clean Water Act amendments is eligible for the 
exclusion so long as the system is in compliance with currently 
applicable Clean Water Act requirements, such as treating water such 
that discharges, if any, from the system meet the Act's requirements. A 
waste treatment system constructed after passage of the 1972 Clean 
Water Act amendments is similarly eligible for the exclusion if it was 
constructed and is operating in a manner that is consistent with the 
Act, such as by treating water so that discharges, if any, from the 
system meet the Act's requirements, and it was constructed in 
compliance with the Act's requirements (e.g., where the system was 
lawfully created pursuant to a section 404 permit). A waste treatment 
system that was created after the 1972 amendments but was constructed 
in violation of the Clean Water Act--for example, a system constructed 
without a section 404 permit when one was necessary--is not eligible 
for the exclusion, regardless of whether the system is currently 
treating discharges to meet the Act's requirements.
    Finally, several commenters asserted that the waste treatment 
system exclusion violates the Clean Water Act. The agencies disagree 
that the waste treatment system exclusion is contrary to the Clean 
Water Act. Waste treatment systems have been excluded from the 
definition of ``waters of the United States'' since 1979, and the waste 
treatment system exclusion is a reasonable and lawful exercise of the 
agencies' authority to determine the scope of ``waters of the United 
States.'' See Ohio Valley Envtl. Coal. v. Aracoma Coal Co., 556 F.3d 
177, 212 (4th Cir. 2009) (upholding the waste treatment system 
exclusion as a lawful exercise of the agencies' ``authority to 
determine which waters are covered by the CWA'').
iii. Implementation
    Consistent with the 1986 regulations, this rule provides that a 
waste treatment system must be ``designed to meet the requirements of 
the Clean Water Act.'' A waste treatment system may be ``designed to 
meet the requirements of the Clean Water Act'' where, for example, it 
is constructed pursuant to a Clean Water Act section 404 permit, Ohio 
Valley Envtl. Coalition v. Aracoma Coal Co., 556 F.3d 177, 214-15 (4th 
Cir. 2009), or where it is ``incorporated in an NPDES permit as part of 
a treatment system,'' N. Cal. River Watch v. City of

[[Page 3111]]

Healdsburg, 496 F.3d 993, 1001 (9th Cir. 2007).
    To be clear, the exclusion does not free a discharger from the need 
to comply with the Clean Water Act, including any effluent limitations 
guidelines and new source performance standards requirements applicable 
to the waste treatment system, and requirements applicable to the 
pollutants discharged from a waste treatment system to ``waters of the 
United States''; only discharges into the waste treatment system are 
excluded from the Act's requirements. As such, any entity would need to 
comply with the Clean Water Act by obtaining a section 404 permit for a 
new waste treatment system that will be constructed in ``waters of the 
United States,'' and a section 402 permit if there are discharges of 
pollutants from a waste treatment system into ``waters of the United 
States.'' Under the section 402 permit, discharges from the waste 
treatment system would need to meet the requirements of applicable 
effluent limitations guidelines and new source performance standards, 
as well as any required water quality-based effluent limitations. 
Further, consistent with the agencies' general practice implementing 
the exclusion, under this rule, a waste treatment system that ceases to 
serve the treatment function for which it was designed would not 
continue to qualify for the exclusion and could be deemed 
jurisdictional if it otherwise meets this rule's definition of ``waters 
of the United States.''
    Moreover, as explained in section IV.C.7 of this preamble, the 
exclusions in this rule--including the waste treatment system 
exclusion--do not apply to features that, at the time they are 
assessed, are jurisdictional under paragraph (a)(1). Note, however, 
that an excluded waste treatment system--such as a cooling pond--may 
over time take on the characteristics of a jurisdictional water, such 
as a paragraph (a)(1) traditional navigable water.\117\ In this 
scenario, the exclusion continues to apply and the waste treatment 
system does not become a jurisdictional water under paragraph (a)(1) or 
any other provision of the rule, unless or until the system ceases to 
serve the treatment function for which it was designed (as discussed in 
the immediately preceding paragraph).
---------------------------------------------------------------------------

    \117\ This situation may arise where, for example, a manmade 
cooling pond constructed in uplands takes on the characteristics of 
a traditional navigable water.
---------------------------------------------------------------------------

    With respect to the scope of the waste treatment system exclusion 
in this rule, the agencies do not interpret the exclusion to allow any 
party to dispose of waste or discharge pollutants into the excluded 
feature without authorization. Rather, for waters that would otherwise 
meet this rule's definition of ``waters of the United States,'' the 
agencies' intent, consistent with prior application of the NPDES 
program, is that the waste treatment system exclusion is generally 
available only for discharges associated with the treatment function 
for which the system was designed. Relatedly, consistent with the 
agencies' longstanding practice, a waste treatment system does not 
itself sever upstream waters from Clean Water Act jurisdiction.\118\ In 
other words, if those upstream waters were ``waters of the United 
States,'' they remain ``waters of the United States'' and discharges to 
them thus may require a section 402 or 404 permit.
---------------------------------------------------------------------------

    \118\ See, e.g., Memorandum of Non-Concurrence with 
Jurisdictional Determinations POA-1992-574 & POA-1992-574-Z (October 
25, 2007), available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll5/id/1454 (``EPA and the Corps agree 
that the agencies' designation of a portion of waters of the U.S. as 
part of a waste treatment system does not itself alter CWA 
jurisdiction over any waters remaining upstream of such system.'').
---------------------------------------------------------------------------

c. Other Exclusions
    In this rule, the agencies are codifying exclusions for several 
features that they generally considered non-jurisdictional under the 
pre-2015 regulatory regime and the 2019 Repeal Rule and expressly 
excluded by regulation in the 2015 Clean Water Rule and 2020 NWPR. 
These features are: ditches (including roadside ditches) excavated 
wholly in and draining only dry land and that do not carry a relatively 
permanent flow of water; artificially irrigated areas that would revert 
to dry land if the irrigation ceased; artificial lakes or ponds created 
by excavating or diking dry land to collect and retain water and which 
are used exclusively for such purposes as stock watering, irrigation, 
settling basins, or rice growing; artificial reflecting or swimming 
pools or other small ornamental bodies of water created by excavating 
or diking dry land to retain water for primarily aesthetic reasons; 
waterfilled depressions created in dry land incidental to construction 
activity and pits excavated in dry land for the purpose of obtaining 
fill, sand, or gravel unless and until the construction or excavation 
operation is abandoned and the resulting body of water meets the 
definition of waters of the United States; and swales and erosional 
features (e.g., gullies, small washes) characterized by low volume, 
infrequent, or short duration flow.
    Under the pre-2015 regulatory regime, the features listed above 
were generally not considered ``waters of the United States'' even 
though they were not explicitly excluded by regulation. The preamble to 
the 1986 regulations explained that the agencies ``generally do not 
consider [these] waters to be `Waters of the United States.' '' 51 FR 
41217 (November 13, 1986). The preamble further stated that ``the Corps 
reserves the right on a case-by-case basis to determine that a 
particular waterbody within these categories of waters is a water of 
the United States. EPA also has the right to determine on a case-by-
case basis if any of these waters are `waters of the United States.''' 
Id. The Rapanos Guidance expanded on the list of features that were 
generally considered non-jurisdictional. Rapanos Guidance at 11-12. In 
practice, the agencies did not generally assert jurisdiction over such 
waters. To provide clarity on which waters are jurisdictional and which 
are not, and to enhance certainty for the public, the agencies are 
codifying exclusions for these features in the regulatory text and 
removing the possibility that these waters could be found 
jurisdictional on a case-by-case basis. Because the agencies did not 
generally assert jurisdiction over these features in practice, 
codifying exclusions for these features is not a substantial change 
from the pre-2015 regulatory regime or the 2019 Repeal Rule. Many 
commenters supported codifying exclusions for these features. This 
approach is generally consistent with the 2015 Clean Water Rule and 
2020 NWPR and will be familiar to the public.
    In the final regulatory text for these exclusions, the agencies are 
consistently using the term ``dry land,'' rather than ``upland.'' The 
proposed rule and the pre-2015 regulatory regime used the phrases ``dry 
land'' and ``upland'' interchangeably in their description of features 
that the agencies considered to be generally non-jurisdictional. To 
provide additional clarity, the agencies are consistently using the 
term ``dry land'' throughout the regulatory text.\119\ The term ``dry 
land'' refers to areas of the geographic landscape that do not include 
waters such as streams, rivers, wetlands, lakes, ponds, tidal waters, 
ditches, and the like. It is important to note that jurisdictional and 
non-jurisdictional waters are not considered ``dry land'' just because 
they lack water

[[Page 3112]]

at a given time. Similarly, an area may remain ``dry land'' even if it 
is wet after a precipitation event.
---------------------------------------------------------------------------

    \119\ While the agencies consistently use the phrase ``dry 
land'' in the regulatory text to provide clarity to the public, this 
preamble and documents supporting this rule use the phrases ``dry 
land'' and ``upland'' interchangeably.
---------------------------------------------------------------------------

    The agencies recognize that for certain longstanding exclusions, 
the 2020 NWPR replaced the word ``upland'' in the regulatory text with 
the word ``upland'' and a reference to non-jurisdictional features. For 
example, the 2020 NWPR regulatory text excluded ``[w]ater-filled 
depressions constructed or excavated in upland or in non-jurisdictional 
waters.'' 85 FR 22338 (April 21, 2020) (emphasis added). This approach 
was a deviation from longstanding practice as both the pre-2015 
regulatory regime and the 2015 Clean Water Rule limited the exclusions 
to features constructed in upland. The distinction between ``upland'' 
or ``dry land'' and ``non-jurisdictional features'' is important 
because ``non-jurisdictional features'' can include features like 
certain ephemeral streams and wetlands that are not jurisdictional but 
are not ``dry.'' This change in the 2020 NWPR resulted in an expansion 
of the exclusion as compared to the pre-2015 regulatory regime. The 
agencies disagree with the approach in the 2020 NWPR. It deviated from 
the longstanding concept of limiting certain exclusions to instances 
where features are constructed in dry land. Limiting the exclusions in 
this rule to features constructed in dry land more appropriately 
captures the agencies' intent to exclude features associated with areas 
that are commonly understood as ``dry.'' Limiting the exclusions in 
this way also puts reasonable bounds on these categorical exclusions 
and ensures that features constructed in land that is not dry are 
examined more closely to determine whether they are jurisdictional.
i. Ditches
(1) This Rule
    In this rule, the agencies are codifying an exclusion for ditches 
(including roadside ditches) excavated wholly in and draining only dry 
lands and that do not carry a relatively permanent flow of water. 
Excluding these ditches from jurisdiction is consistent with the scope 
of ditches that were generally non-jurisdictional under the pre-2015 
regulatory regime and the 2019 Repeal Rule. The preamble to the 1986 
regulations explains that ``[n]on-tidal drainage and irrigation ditches 
excavated on dry land'' are generally not considered ``waters of the 
United States.'' 51 FR 41217 (November 13, 1986). The agencies shifted 
this approach slightly in the Rapanos Guidance and explained that 
``ditches (including roadside ditches) excavated wholly in and draining 
only uplands and that do not carry a relatively permanent flow of water 
are generally not waters of the United States.'' Rapanos Guidance at 
11-12. Excluding certain ditches from jurisdiction is also consistent 
with the 2015 Clean Water Rule and the 2020 NWPR. While these rules 
took different approaches to determining which ditches should be 
excluded, due in part to different overall constructs for the 
definition of ``waters of the United States'' under those rules, both 
rules excluded some ditches. The agencies, in this rule, are continuing 
the approach described in the Rapanos Guidance and are codifying that 
approach in the regulatory text to provide clarity and certainty. As 
discussed above, the agencies are also maintaining their longstanding 
position that paragraph (a)(1) waters are not subject to the exclusions 
and, most relevant to the exclusion for ditches and consistent with the 
1986 preamble, tidal ditches will continue to be jurisdictional under 
paragraph (a)(1). Continuing the approach described in the Rapanos 
Guidance is consistent with the agencies' intent with this rule to 
interpret ``waters of the United States'' to mean the waters defined by 
the longstanding 1986 regulations, with amendments to reflect the 
agencies' interpretation of the statutory limits on the scope of the 
``waters of the United States,'' informed by the text of the relevant 
provisions of the Clean Water Act and the statute as a whole, the 
scientific record, relevant Supreme Court case law, public comment, and 
the agencies' experience and technical expertise after more than 45 
years of implementing the longstanding pre-2015 regulations defining 
``waters of the United States.''
(2) Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    Consistent with the Rapanos Guidance, this rule excludes ``ditches 
(including roadside ditches) that are excavated wholly in and draining 
only dry land and that do not carry a relatively permanent flow of 
water.'' Rapanos Guidance at 8. The scope of the ditch exclusion is 
consistent with the agencies' longstanding practice and technical 
judgment that certain waters and features are not subject to regulation 
under the Clean Water Act. The exclusion is also informed by Rapanos. 
The agencies have concluded that the relatively permanent standard in 
Rapanos on its own is insufficient to achieve the objective of the Act. 
See section IV.A of this preamble. However, the relatively permanent 
standard is generally consistent with the agencies' longstanding 
practice of finding certain ditches that lack important hydrogeomorphic 
features to be non-jurisdictional. The ditches excluded under this rule 
and longstanding practice are often part of Tribal, State, and local 
land use planning and can also be subject to Tribal or State 
jurisdiction, as the Clean Water Act recognizes that Tribes and States 
can regulate more broadly than the Federal Government. Excluding 
certain ditches from jurisdiction under this rule also improves 
administrative efficiency and provides certainty and clarity to the 
public. This exclusion simplifies the approved jurisdictional 
determination process and makes it more straightforward for agency 
staff to implement the rule and for the public to determine whether 
certain features are subject to Federal jurisdiction.
    Several commenters requested that the agencies exclude a broader 
set of ditches from the definition of ``waters of the United States.'' 
The agencies find that it would not be appropriate to exclude a broader 
set of ditches from the definition of ``waters of the United States'' 
in this rule. Congress clearly intended that some ditches are 
jurisdictional under the Clean Water Act. The Clean Water Act states 
that, with some exceptions, the discharge of dredge or fill material 
``for the purpose of construction or maintenance of farm or stock ponds 
or irrigation ditches, or the maintenance of drainage ditches'' is not 
prohibited by or otherwise subject to regulation under the Clean Water 
Act. 33 U.S.C. 1344(f)(1)(C). Because this exemption only applies to 
discharges of dredged or fill material into ``waters of the United 
States,'' there would be no need for such a permitting exemption if all 
ditches were considered non-jurisdictional under the Clean Water Act. 
The agencies in the 2020 NWPR similarly interpreted section 404(f) as 
an indication that Congress intended that ditches could in some 
instances be jurisdictional under the Clean Water Act. 85 FR 22297 
(April 21, 2020). The agencies' approach in this rule--which finds that 
some ditches are jurisdictional while others are not--reflects full and 
appropriate consideration of section 404(f), the water quality 
objective in Clean Water Act section 101(a), and the policies relating 
to responsibilities and rights of Tribes and States under section 
101(b). The approach of finding certain ditches jurisdictional while 
excluding others from jurisdiction is also consistent with the 2015 
Clean Water Rule and the 2020 NWPR, as well as the pre-2015

[[Page 3113]]

regulatory regime and the 2019 Repeal Rule. Human-made tributaries like 
ditches can provide functions that restore and maintain the chemical, 
physical, and biological integrity of downstream paragraph (a)(1) 
waters. The scientific literature indicates that structures like 
ditches that convey water continue to connect to and effect downstream 
waters, though the connectivity and effects can be different than that 
of natural streams. Indeed, ditches can enhance the extent of 
connectivity by more effectively conveying the water downstream. See 
section III.A of the Technical Support Document for additional 
information; see also section IV.A.2.b.i of this preamble for further 
discussion of these issues.
    Several commenters asked for additional explanation of terms and 
phrases used in the exclusion for certain ditches. The phrase 
``excavated wholly in and draining only dry land'' means that at the 
time the ditch was constructed, it was excavated in dry land as that 
term is described above. It further means that at the time of 
construction, the ditch was excavated entirely, or wholly, in dry land. 
Finally, it means that the ditch is not situated close enough to a 
water feature, including wetlands, to drain that water feature. For 
example, a ditch that is constructed in dry land and receives water 
from runoff and other ditches constructed in dry land and draining only 
dry land, or from groundwater intercepted as the ditch was dug, would 
be considered a ditch ``excavated wholly in and draining only dry 
land.'' In contrast, a ditch that is constructed in dry land but also 
drains a wetland would not be considered a ditch that drains only dry 
land, and a ditch constructed in both a wetland and in dry land would 
not be considered to be excavated wholly in dry land. The 
jurisdictional status of a ditch is assessed on a case-by-case basis by 
considering the specific characteristics of the site at issue.
    The phrase ``do not carry a relatively permanent flow of water'' 
means that the ditch is not a relatively permanent water as that term 
is explained in this rule. Relatively permanent flow, as discussed in 
section IV.C.4.c.ii of this preamble, means the ditch contains flowing 
or standing water year-round or continuously during certain times of 
the year for more than a short duration in direct response to 
precipitation. The language ``do not carry a relatively permanent flow 
of water'' is consistent with the language in the Rapanos Guidance.
    The use of the word ``and'' in the exclusion for ditches indicates 
that all three criteria (excavated wholly in dry land, draining only 
dry land, and not carrying a relatively permanent flow of water) must 
be satisfied for the ditch to be excluded. However, even where a ditch 
is not excluded, it is only jurisdictional if it satisfies the terms of 
the categories of waters that are considered jurisdictional under this 
rule. For example, a ditch that is not excluded, but does not satisfy 
either the relatively permanent or significant nexus standard would not 
be jurisdictional under this rule.
    In addition, the agencies' longstanding interpretation of the Clean 
Water Act is that it is not relevant whether a water has been 
constructed or altered by humans for purposes of determining whether a 
water is jurisdictional under the Clean Water Act. In S.D. Warren v. 
Maine Board of Envt'l Protection, Justice Stevens, writing for a 
unanimous Court, stated: ``nor can we agree that one can denationalize 
national waters by exerting private control over them.'' 547 U.S. 370, 
379 n.5 (2006). In Rapanos, all members of the Court generally agreed 
that ``highly artificial, manufactured, enclosed conveyance systems--
such as `sewage treatment plants,' . . . and the `mains, pipes, 
hydrants, machinery, buildings, and other appurtenances and incidents' 
. . . likely do not qualify as `waters of the United States,' despite 
the fact that they may contain continuous flows of water.'' 547 U.S. at 
737 (Scalia, J., plurality opinion). But there was also agreement that 
certain waters that are human-made or man-altered, such as canals with 
relatively permanent flow, are ``waters of the United States.'' Id. at 
736 n.7. Justice Kennedy and the dissent rejected the conclusion that 
because the word ``ditch'' was in the definition of ``point source'' a 
ditch could never be ``waters of the United States'': ``certain water 
bodies could conceivably constitute both a point source and a water.'' 
Id. at 772 (Kennedy, J., concurring in the judgment); see also id. at 
802 (Stevens, J., dissenting) (``The first provision relied on by the 
plurality--the definition of `point source' in 33 U.S.C. 1362(14)--has 
no conceivable bearing on whether permanent tributaries should be 
treated differently from intermittent ones, since `pipe[s], ditch[es], 
channel[s], tunnel[s], conduit[s], [and] well[s]' can all hold water 
permanently as well as intermittently.''). While the plurality, Justice 
Kennedy, and the dissent formulated different standards for determining 
what are ``waters of the United States,'' none of the standards 
qualified jurisdiction on a distinction between ``natural'' versus 
``human-made'' or ``human-altered'' waters or excluded ditches in their 
entirety. Further, no Federal Court of Appeals has interpreted Rapanos 
to exclude ditches from the Clean Water Act. This case law demonstrates 
that certain ditches have long been subject to regulation as ``waters 
of the United States.''
    Several commenters suggested that certain types of ditches, 
including roadside ditches, ditches associated with railroad 
operations, and agricultural ditches, should be excluded in this rule. 
This rule does not explicitly exclude these types of ditches, but the 
exclusions included in this rule address many ditches of these types. 
Moreover, since the exclusion for ditches in this rule focuses on the 
physical (e.g., constructed in dry land) and flow characteristics of 
ditches, the exclusion addresses all ditches that the agencies have 
concluded should not be subject to jurisdiction, including certain 
ditches on agricultural lands and ditches associated with modes of 
transportation, such as roadways, airports, and rail lines.
(3) Implementation
    When assessing the jurisdictional status of a ditch, the agencies 
will evaluate the entire reach of the ditch to determine if it has 
relatively permanent flow, consistent with the reach approach for 
tributaries described in section IV.C.4.c of this preamble. As 
described for tributaries, the agencies will assess the flow 
characteristics of a particular ditch reach at the farthest downstream 
limit of the ditch reach (i.e., the point the ditch enters a higher 
order in the network). Where data indicate the flow characteristics at 
the downstream limit is not representative of the entire reach of the 
ditch, the flow characteristics that best characterizes the entire 
ditch reach will be used. For example, if the majority of the ditch 
reach lacks relatively permanent flow but some portions of the reach 
contain isolated pools of standing water, that reach of the ditch 
likely would not be considered to have relatively permanent flow. As a 
result, such a ditch could be excluded from jurisdiction if it 
satisfies the other requirements of the ditch exclusion. Additionally, 
a situation could arise where there is one reach of a ditch with 
relatively permanent flow that is jurisdictional and is connected to 
downstream waters via a separate reach of the ditch that is non-
jurisdictional. This approach to evaluating jurisdiction of each reach 
of a ditch separately is

[[Page 3114]]

consistent with the agencies' approach for evaluating jurisdiction over 
tributaries, which evaluates each reach of a tributary separately. See 
section IV.C.4.c.ii of this preamble for further discussion of applying 
the relatively permanent standard to tributary reaches.
    Questions have sometimes arisen regarding the distinctions between 
ditches and human-altered natural streams and rivers. Alteration or 
modification of a natural stream or river for flood control, erosion 
control, development, agriculture, and other reasons does not convert 
the stream or river to an excluded ditch. A stream or river that has 
been channelized or straightened because its natural sinuosity has been 
altered, cutting off the meanders, is not a ditch. A stream that has 
banks stabilized through use of concrete or rip-rap (e.g., rocks or 
stones) is not a ditch. In these instances, the altered or modified 
streams and rivers are not ditches and would also not satisfy the 
exclusion for ditches because they are not ``excavated wholly in and 
draining only dry land.'' See section IV.A.2.b.i of this preamble for 
further discussion of this rule's coverage of human-made or human-
altered tributaries.
    Questions have also arisen regarding relocated streams and rivers. 
A stream or river that has been relocated is not a ditch and would also 
not satisfy the exclusion for ditches because it is not ``excavated 
wholly in and draining only dry land.'' A stream or river that is 
relocated should be evaluated as a tributary when it contributes flow 
directly or indirectly to a paragraph (a)(1) water. A stream or river 
is considered relocated either when at least a portion of its original 
channel has been physically moved, or when the majority of its flow has 
been redirected. Even where the stream or river has been relocated 
(i.e., the majority of its flow has been redirected), the remnant 
portions of the former stream may still be jurisdictional where it 
satisfies the terms of paragraph (a) of this rule.
    The agencies note that an excluded ditch that connects downstream 
to a jurisdictional tributary would not be jurisdictional merely 
because of its downstream connection to the jurisdictional tributary. 
Furthermore, wetlands that develop entirely within the confines of an 
excluded ditch are not jurisdictional, as discussed further in section 
IV.C.5.b of this preamble.
    Certain excluded ditches (such as roadside and agricultural ditches 
that satisfy the requirements of the ditch exclusion) may receive 
backflow from a jurisdictional water, such as a perennial river that 
overflows into the ditch and extends the OHWM of the contributing water 
into the ditch. In these circumstances, the agencies will continue the 
practice of extending the OHWM of the jurisdictional contributing water 
up to the location of its OHWM within the otherwise non-jurisdictional 
ditch, as required by Corps regulations. See 33 CFR 328.4(c). In these 
instances, the ditch is not necessarily jurisdictional; the feature 
extending into the ditch is jurisdictional. For example, an excluded 
ditch may connect with a relatively permanent river, and at times, high 
flows from the river may extend into the excluded ditch such that the 
OHWM of the jurisdictional river also extends into the ditch. The 
agencies will continue to treat the portion of the relatively permanent 
river that extends into the excluded ditch, up to the OHWM of the 
river, as part of the jurisdictional river. The ditch remains excluded, 
but the flow in the ditch that is from the relatively permanent river 
will be jurisdictional as part of the river.
    The agencies will use the most accurate and reliable resources to 
support their decisions regarding whether a feature is an excluded 
ditch. This will typically involve the use of multiple sources of 
information and those sources may differ depending on the resource in 
question or the region in which the resource is located. Along with 
field data and other current information on the subject waters, 
historic tools and resources may be used to determine whether a feature 
is an excluded ditch. Several sources of information may be required to 
make such determination. Information sources may include historic and 
current topographic maps, historic and recent aerial photographs, 
Tribal, State, and local records and surface water management plans 
(such as county ditch or drainage maps and datasets), NHD or NWI data, 
agricultural records, street maintenance data, precipitation records, 
historic permitting and jurisdictional determination records, certain 
hydrogeomorphological or soil indicators, wetlands and conservation 
programs and plans, and functional assessments and monitoring efforts. 
For example, when a USGS topographic map displays a tributary located 
upstream and downstream of a potential ditch, this may indicate that 
the potential ditch was constructed in or relocated a tributary. As 
another example, an NRCS soil survey displaying the presence of 
specific soil series which are linear in nature and generally parallel 
to a potential ditch may be indicative of alluvial deposits formed by a 
tributary in which the potential ditch was constructed. Additionally, 
the presence of a pond in a historic aerial photograph that lies along 
the flowpath of the potential ditch, for example, may provide an 
indication that the potential ditch was not constructed wholly in and 
drained only dry land.
    This rule does not affect the permitting exemptions for certain 
activities described in Clean Water Act section 404(f), including the 
exemption in section 404(f)(1)(C) for the construction and maintenance 
of irrigation ditches and the maintenance of drainage ditches. The 
agencies have historically taken the position that a ditch can be both 
``waters of the United States'' and a point source. The 2020 NWPR, 
however, changed the agencies' longstanding position and stated that a 
ditch is either ``waters of the United States'' or a point source. 85 
FR 22297 (April 21, 2020). The 2020 NWPR justified this position by 
noting that the Clean Water Act defines ``point sources'' to include 
ditches and that the plurality opinion in Rapanos stated that ``[t]he 
definitions thus conceive of `point sources' and `navigable waters' as 
separate and distinct categories. The definition of `discharge' would 
make little sense if the two categories were significantly 
overlapping.'' See 547 U.S. at 735-36 (Scalia, J., plurality opinion); 
NWPR Response to Comments, Section 6 at 12-13.
    The agencies have further evaluated this question and concluded 
that the better reading of the statute is the agencies' historic 
position that a ditch can be both a point source and ``waters of the 
United States.'' That position dates back to 1975 in an opinion of the 
General Counsel of EPA interpreting the Clean Water Act. That opinion 
stated: ``it should be noted that what is prohibited by section 301 is 
`any addition of any pollutant to navigable waters from any point 
source.' It is therefore my opinion that, even should the finder of 
fact determine that any given irrigation ditch is a navigable water, it 
would still be permittable as a point source where it discharges into 
another navigable water body, provided that the other point source 
criteria are also present.'' In re Riverside Irrigation District, 1975 
WL 23864, at *4 (June 27, 1975) (emphasis in original). The opinion 
stated that ``to define the waters here at issue as navigable waters 
and use that as a basis for exempting them from the permit requirement 
appears to fly directly in the face of clear legislative intent to the 
contrary.'' Id.
    In addition, in Rapanos, Justice Kennedy and the dissent rejected 
the

[[Page 3115]]

conclusion that because the word ``ditch'' was in the definition of 
``point source'' a ditch could never be ``waters of the United 
States'': ``certain water bodies could conceivably constitute both a 
point source and a water.'' 547 U.S. at 772 (Kennedy, J., concurring in 
the judgment); see also id. at 802 (Stevens, J., dissenting) (``The 
first provision relied on by the plurality--the definition of ``point 
source'' in 33 U.S.C. [section] 1362(14)--has no conceivable bearing on 
whether permanent tributaries should be treated differently from 
intermittent ones, since `pipe[s], ditch[es], channel[s], tunnel[s], 
conduit[s], [and] well[s]' can all hold water permanently as well as 
intermittently.'').\120\ Even the plurality opinion in Rapanos, which 
was relied upon by the agencies in the 2020 NWPR for its change in 
position, left room for some ditches to both point sources and ``waters 
of the United States,'' finding that the two categories should not be 
``significantly'' overlapping. 547 U.S. at 735-36 (Scalia, J., 
plurality opinion).
---------------------------------------------------------------------------

    \120\ The agencies considered that a district court has reached 
a contrary conclusion, but the agencies decline to adopt the 
decision's reasoning in this rule, including because it relies on 
the change in interpretation articulated for the first time in the 
2020 NWPR and which the agencies reject in this rule, and is 
inconsistent with the position of five Justices in Rapanos. See 
Toxics Action Center, Inc. & Conservation Law Found. v. Casella 
Waste Systems, Inc., 2021 WL 3549938, *8 (D.N.H. Aug. 11, 2021) 
(``If a waterway can simultaneously be a navigable water (that is, a 
water of the United States) and a point source, the distinction the 
statute draws between the two categories using the prepositions 
`from' and `to' would be rendered meaningless.'').
---------------------------------------------------------------------------

    There is simply no indication in the text of the Clean Water Act 
that ditches that meet the definition of a point source cannot also be 
``waters of the United States.'' To the contrary, the fact that 
Congress provided an exemption for discharges of dredged or fill 
material for construction or maintenance of certain types of ditches 
from permitting in Clean Water Act section 404(f) is further evidence 
that under the plain language of the statute ditches can, at least in 
some cases, be both point sources and ``waters of the United States.'' 
The agencies therefore find that their longstanding, historic view that 
a ditch can be both a point source and ``waters of the United States'' 
is the better interpretation.
ii. Other Features
(1) This Rule
    In this rule, the agencies are codifying exclusions for certain 
other features that were not generally considered jurisdictional under 
the pre-2015 regulatory regime. Consistent with the features listed in 
the preamble to the 1986 regulations, the agencies are codifying 
exclusions for: artificially irrigated areas that would revert to dry 
land if the irrigation ceased; artificial lakes or ponds created by 
excavating and/or diking dry land to collect and retain water and which 
are used exclusively for such purposes as stock watering, irrigation, 
settling basins, or rice growing; artificial reflecting or swimming 
pools or other small ornamental bodies of water created by excavating 
and/or diking dry land to retain water for primarily aesthetic reasons; 
and waterfilled depressions created in dry land incidental to 
construction activity and pits excavated in dry land for the purpose of 
obtaining fill, sand, or gravel unless and until the construction or 
excavation operation is abandoned and the resulting body of water meets 
the definition of ``waters of the United States.'' See 51 FR 41217 
(November 13, 1986). In addition, consistent with the Rapanos Guidance, 
the agencies are excluding swales and erosional features (e.g., 
gullies, small washes) characterized by low volume, infrequent, or 
short duration flow. See Rapanos Guidance at 11-12. Excluding these 
features from jurisdiction is consistent with the 2015 Clean Water Rule 
and the 2020 NWPR, as well as the pre-2015 regulatory regime and the 
2019 Repeal Rule, which considered these features to be generally non-
jurisdictional. The agencies are codifying exclusions for these 
features in the regulatory text to provide clarity and certainty.
    The agencies are finalizing two minor changes to the exclusion for 
swales and erosional features in this rule as compared to the language 
in the Rapanos Guidance. The Guidance explained that the agencies 
generally found ``[s]wales or erosional features (e.g., gullies, small 
washes characterized by low volume, infrequent, or short duration 
flow)'' to be non-jurisdictional. Rapanos Guidance at 11-12. First, 
this rule's regulatory text excludes ``swales and erosional features'' 
rather than ``swales or erosional features.'' The agencies find that 
the use of ``or'' in this phrase in the Rapanos Guidance was confusing 
because swales are substantively different from erosional features and 
thus should not be referred to in the alternative. To provide 
additional clarity, the agencies are using the connector ``and'' in 
this rule's regulatory text for this exclusion. Second, the agencies 
are moving the parentheses in this provision so that only the phrase 
``e.g., gullies, small washes'' is included in parentheses. This change 
clarifies that the rest of the language in this exclusion, 
``characterized by low volume, infrequent, or short duration flow'' 
applies to both swales and erosional features. This change ensures that 
the exclusion more accurately describes those swales and erosional 
features which are discrete topographic features on the landscape, 
rather than low gradient depressional areas that convey only overland 
sheetflow and which are not included within this exclusion. The 
agencies are making these two ministerial changes from the Rapanos 
Guidance to provide additional clarity in this rule, but the agencies' 
application of the exclusion for these features as compared to the pre-
2015 regulatory regime remains substantively and operationally 
unchanged.
(2) Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    As described at the beginning of this section, codifying exclusions 
for these features is consistent with the agencies' longstanding 
practice that certain waters and features are not subject to the Clean 
Water Act. The exclusions are also guided by Supreme Court cases that 
recognized that there are certain features that were not primarily the 
focus of the Clean Water Act. See, e.g., Rapanos 547 U.S. at 734. The 
exclusions are an important aspect of the agencies' policy goal of 
providing clarity, certainty, and predictability for the regulated 
public and regulators. The categorical exclusions will simplify the 
process of determining jurisdiction, and they reflect the agencies' 
determinations of the lines of jurisdiction based on the case law, 
policy determinations, and the agencies' experience and expertise.
    Many commenters generally supported adding the exclusions in the 
regulatory text. Several of these commenters stated that adding the 
exclusions to the regulatory text would provide clarity and certainty 
and avoid time and cost burdens. The agencies agree with these 
commenters and have added these exclusions, along with the exclusion 
for ditches, to the regulatory text. Other commenters stated that 
exclusions of certain waterbodies were not based on science or the 
significant nexus standard. Determinations about the scope of ``waters 
of the United States'' are informed by science but also informed by the 
agencies' decades of implementation experience. This rule reflects the 
judgment of the agencies in balancing the science, the agencies' 
expertise, and the regulatory goals of providing clarity to the public 
while

[[Page 3116]]

protecting the integrity of paragraph (a)(1) waters, consistent with 
the law.
(3) Implementation
    This section addresses implementation of the exclusions for certain 
other features that were not generally considered jurisdictional under 
the pre-2015 regulatory regime in the order in which the relevant 
provision appears in the regulatory text.
    In this rule, the agencies clarify their longstanding view that the 
exclusion for certain artificially irrigated areas applies only to the 
specific land being directly irrigated that would reasonably revert to 
dry land should irrigation cease. The exclusion does not apply to all 
waters within watersheds where irrigation occurs.
    Questions have arisen in the past regarding whether a feature that 
initially satisfied the terms of an exclusion but no longer satisfies 
those terms continues to be excluded from jurisdiction. For example, if 
an artificial pond created by excavating land to collect and retain 
water is initially used exclusively for stock watering, irrigation, 
settling basins, or rice growing but is subsequently used for a 
different purpose, the question has arisen whether that pond is still 
excluded from jurisdiction. Consistent with the agencies' longstanding 
practice, if a previously excluded feature no longer meets the terms of 
the exclusion, it is no longer excluded. If it no longer satisfies the 
terms of an exclusion, it would be jurisdictional if it otherwise meets 
the definition of ``waters of the United States'' under this rule.
    The agencies recognize that artificial lakes and ponds are often 
used for more than one purpose and can have other beneficial purposes, 
such as animal habitat, water retention, or recreation. For example, 
artificial lakes and ponds that are created by excavating dry land to 
collect and retain water for stock watering are often extensively used 
by waterfowl and other wildlife. The agencies' historic practice, which 
the agencies intend to continue under this rule, is to consider these 
features as excluded even when there is another incidental beneficial 
use of the feature.
    The artificial lakes and ponds exclusion applies only to those 
lakes and ponds that satisfy the terms of the exclusion. Paragraph 
(a)(2) impoundments are not covered under this exclusion. This 
exclusion only applies to features that were excavated in dry land or 
were diked in dry land. Paragraph (a)(2) impoundments are not excavated 
in dry land or diked in dry land. However, consistent with the 
agencies' longstanding practice, when an applicant receives a permit to 
impound ``waters of the United States'' to construct a waste treatment 
system, the resulting waste treatment system is subject to that 
exclusion as long as it is used for this permitted purpose. See the 
discussion above regarding waste treatment systems.
    Artificial lakes and ponds that satisfy the terms of the exclusion 
would not be jurisdictional under this rule even if they have a 
hydrologic surface connection to ``waters of the United States.'' Non-
jurisdictional conveyances created in dry land that are physically 
connected to and are a part of the excluded feature remain excluded.
    Swales and erosional features are excluded when characterized by 
low volume, infrequent, or short duration flow. Swales are generally 
shallow features in the landscape that may convey water across dry land 
areas during and following storm events and typically have grass or 
other low-lying vegetation throughout the swale. While a swale is a 
discrete topographic feature, it does not have a defined channel, nor 
an OHWM. This distinguishes a swale from an ephemeral stream because 
ephemeral streams typically have a channel and at least one indicator 
of an OHWM. See section IV.A.ii of the Technical Support Document for 
additional discussion of swales. Erosional features can typically be 
distinguished from swales because erosional features are generally 
deeper than swales and have an absence of vegetation. Erosional 
features can be distinguished from tributaries by the absence of a 
channel and an OHWM. Concentrated surface runoff can occur within 
erosional features without creating the permanent physical 
characteristics associated with a channel and OHWM. Some ephemeral 
streams are colloquially called ``gullies'' or the like even when they 
exhibit a channel and an OHWM. Regardless of the name they are given 
locally, waters that are tributaries under this rule are not excluded 
erosional features. See Technical Support Document section IV.A.ii for 
additional discussion on how to distinguish between tributaries, 
swales, and erosional features.
    Erosional features like rills and gullies also typically lack a 
defined channel and an OHWM. Rills are very small incisions formed by 
overland water flows eroding the soil surface during rainstorms. Rills 
are less permanent on the landscape than streams. Gullies tend to be 
much smaller than streams, and are often deeper than they are wide, 
with very steep banks. Gullies are commonly found in areas without much 
vegetation or with soils that are prone to erosion.
8. Other Definitions
    The final rule regulatory text defines the terms ``wetlands,'' 
``high tide line,'' ``ordinary high water mark,'' and ``tidal water.'' 
The definitions of these four terms in the final rule are identical to 
the definitions of these terms in the 1986 regulations, 2019 Repeal 
Rule, and 2020 NWPR. While the 1986 regulations included these 
definitions only in the Corps' regulations, not EPA's regulations, the 
2015 Clean Water Rule and 2020 NWPR included these definitions in both 
agencies' regulations. To provide additional clarity and consistency in 
comparison to the 1986 regulations, the final rule includes these 
definitions in both agencies' regulations. The agencies are not 
amending the definitions of these terms from the 1986 regulations.
    The regulatory text in the final rule also defines the term 
``adjacent.'' The agencies amended the definition of ``adjacent'' in 
the 2020 NWPR but are returning to the longstanding definition of that 
term in the 1986 regulations. Returning to the definition of 
``adjacent'' from the 1986 regulations is consistent with the agencies' 
intent to return to the pre-2015 regulatory regime's approach to 
``waters of the United State.'' This section briefly describes these 
five definitions and their history and implementation. See section IV.G 
of this preamble and previous sections of IV.C of this preamble above 
for further discussion on implementation.
    Many commenters suggested that the agencies include additional 
definitions in this rule, including definitions for ``navigable''; 
``similarly situated''; ``tributary''; and ``physical integrity,'' 
``chemical integrity,'' and ``biological integrity.'' The agencies find 
that the regulatory text in this rule and the preamble's explanation of 
the regulatory text clearly present the agencies' definition of 
``waters of the United States'' and that additional definitions are not 
needed. Moreover, the agencies seek to avoid regulatory language that 
is overly detailed or prescriptive, as interpretations of some of these 
terms could vary depending on the region or evolve over time with 
scientific advances.
a. Wetlands
    This rule makes no changes to the definition of ``wetlands'' 
contained in the 1986 regulations (and in the 2020 NWPR, which made no 
changes to the 1986 regulation). ``Wetlands'' are defined as ``those 
areas that are inundated or saturated by surface or

[[Page 3117]]

ground water at a frequency and duration sufficient to support, and 
that under normal circumstances do support, a prevalence of vegetation 
typically adapted for life in saturated soil conditions. Wetlands 
generally include swamps, marshes, bogs, and similar areas.'' Wetlands 
have been defined in the Corps' regulations since 1975 and in EPA's 
regulations since 1979, with only minor differences from the 1986 
regulations. The agencies are not amending this longstanding definition 
in this rule.
    Wetlands, including ``the classic swamplands in the Southeast, such 
as the great Okefenokee, the Great Swamp of New Jersey, . . . the 
majestic, sweeping marshes of the Everglades, the remote Alakai in 
Hawaii, and the tiny bogs of New England,'' Senate Debate, August 4, 
1977, Comments of Mr. Chafee at 13560, are ``transitional areas between 
terrestrial and aquatic ecosystems.'' Science Report at 2-5. Scientific 
systems for classifying areas as wetlands vary but typically include 
three components: ``the presence of water, either at the surface or 
within the root zone,'' ``unique soil conditions,'' and the presence of 
vegetation ``adapted to the wet conditions.'' \121\ The agencies' 
longstanding definition of wetlands, unchanged in this rule, requires 
these three factors of hydrology, hydric soils, and hydrophytic 
vegetation under normal circumstances.
---------------------------------------------------------------------------

    \121\ See William J. Mitsch & James G. Gosselink, Wetlands at 29 
(5th ed. 2015).
---------------------------------------------------------------------------

    Due to the many important functions that wetlands perform that 
impact the integrity of paragraph (a)(1) waters, wetlands have long 
been considered waters that can be subject to Clean Water Act 
jurisdiction. The Corps first added wetlands explicitly in the 
definition of ``waters of the United States'' in 1975 and EPA did the 
same in 1979. 40 FR 31320, 31324-5 (July 25, 1975); 44 FR 32854, 32901 
(June 7, 1979). In contrast, as discussed in section IV.C.7 of this 
preamble, dry lands are areas that do not meet all three wetland 
factors and that are not other waterbody types (such as lakes, ponds, 
streams, ditches, and impoundments). For example, an area that under 
normal circumstances contains only hydrophytic vegetation without the 
presence of wetland hydrology and hydric soils and that lacks an OHWM 
would typically be considered dry land. Only those wetlands that meet 
the provisions to be a paragraph (a)(1) water, jurisdictional adjacent 
wetland, paragraph (a)(2) impoundment, or paragraph (a)(5) water would 
be considered ``waters of the United States'' under this rule.
    As under prior regimes, wetlands are identified in the field in 
accordance with the 1987 U.S. Army Corps of Engineers Wetland 
Delineation Manual and applicable regional delineation manuals. Field 
work is often necessary to confirm the presence of a wetland and to 
accurately delineate its boundaries. However, in addition to field 
observations on hydrology, vegetation, and soils, remote tools and 
resources can be used to support the identification of a wetland.\122\
---------------------------------------------------------------------------

    \122\ Examples include USGS topographic maps (available at 
https://www.usgs.gov/the-national-map-data-delivery/topographic-maps), NRCS soil maps and properties of soils including flood 
frequency and duration, ponding frequency and duration, hydric 
soils, and drainage class (available at https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx or via the 
NRCS Soil Survey Geographic Database (SSURGO) available at https://catalog.data.gov/dataset/soil-survey-geographic-database-ssurgo), 
aerial or high-resolution satellite imagery, high-resolution 
elevation data (e.g., https://apps.nationalmap.gov/downloader/#/), 
and NWI maps (available at https://www.fws.gov/program/national-wetlands-inventory/wetlands-mapper).
---------------------------------------------------------------------------

b. Adjacent
    This rule defines the term ``adjacent'' with no changes from the 
45-year-old definition. ``Adjacent'' is defined as ``bordering, 
contiguous, or neighboring. Wetlands separated from other `waters of 
the United States' by man-made dikes or barriers, natural river berms, 
beach dunes and the like are `adjacent wetlands.' '' This is a 
longstanding and familiar definition that is supported by the text of 
the statute, Supreme Court case law, and science. See, e.g., Riverside 
Bayview, 474 U.S. at 134 (``[T]he Corps' ecological judgment about the 
relationship between waters and their adjacent wetlands provides an 
adequate basis for a legal judgment that adjacent wetlands may be 
defined as waters under the Act.''). Thus, the longstanding definition 
of ``adjacent'' reasonably advances the objective of the Clean Water 
Act. To be jurisdictional under this rule, however, wetlands must meet 
this definition of adjacent and either be adjacent to a traditional 
navigable water, the territorial seas, or an interstate water, or 
otherwise fall within the adjacent wetlands provision and meet either 
the relatively permanent standard or the significant nexus standard. 
The determination of whether a wetland is ``adjacent'' is distinct from 
whether an ``adjacent'' wetland meets the relatively permanent 
standard; however, wetlands that have a continuous surface connection 
to a relatively permanent water meet the definition of ``adjacent'' and 
are, therefore, a subset of adjacent wetlands. See section IV.C.5 of 
this preamble for further discussion of the adjacent wetlands provision 
of this rule.
    The longstanding definition, by its terms, does not require flow 
from the wetland to the jurisdictional water or from the jurisdictional 
water to the wetland (although such flow in either direction can be 
relevant to the determination of adjacency). The Supreme Court in 
Riverside Bayview, in deferring to the Corps' ecological judgment about 
the relationship between waters and their adjacent wetlands as an 
``adequate basis for a legal judgment that adjacent wetlands may be 
defined as waters under the Act,'' rejected an argument that such 
wetlands had to be the result of flow in a particular direction to be 
adjacent: ``This holds true even for wetlands that are not the result 
of flooding or permeation by water having its source in adjacent bodies 
of open water. The Corps has concluded that wetlands may affect the 
water quality of adjacent lakes, rivers, and streams even when the 
waters of those bodies do not actually inundate the wetlands. For 
example, wetlands that are not flooded by adjacent waters may still 
tend to drain into those waters. In such circumstances, the Corps has 
concluded that wetlands may serve to filter and purify water draining 
into adjacent bodies of water, see 33 CFR 320.4(b)(2)(vii) (1985), and 
to slow the flow of surface runoff into lakes, rivers, and streams, and 
thus prevent flooding and erosion, see Sec. Sec.  320.4(b)(2)(iv) and 
(v). In addition, adjacent wetlands may `serve significant natural 
biological functions, including food chain production, general habitat, 
and nesting, spawning, rearing and resting sites for aquatic . . . 
species.' '' 447 U.S at 134-35.
    The agencies will continue their longstanding practice under this 
definition and consider wetlands adjacent if one of the following three 
criteria is satisfied. First, there is an unbroken surface or shallow 
subsurface connection to jurisdictional waters. All wetlands that 
directly abut jurisdictional waters have an unbroken surface or shallow 
subsurface connection because they physically touch the jurisdictional 
water. Wetlands that do not directly abut a jurisdictional water may 
have an unbroken surface or shallow subsurface connection to 
jurisdictional waters. Water does not need to be continuously present 
in the surface or shallow subsurface connection. Second, they are 
physically separated from jurisdictional waters by ``man-made dikes or 
barriers, natural

[[Page 3118]]

river berms, beach dunes, and the like.'' Or third, their proximity to 
a jurisdictional water is reasonably close, such that ``adjacent 
wetlands have significant effects on water quality and the aquatic 
ecosystem.'' Riverside Bayview, 474 U.S. at 135 n.9. See section IV.C.5 
of this preamble.
    ``Adjacent'' under the well-established definition the agencies are 
maintaining in this rule includes wetlands separated from other 
``waters of the United States'' by ``man-made dikes or barriers, 
natural river berms, beach dunes, and the like.'' Such adjacent 
wetlands continue to have a hydrologic connection to the water to which 
they are adjacent because constructed dikes or barriers, natural river 
berms, beach dunes, and the like typically do not block all water flow. 
This hydrologic connection can occur via seepage or over-topping, where 
water from the nearby traditional navigable water, interstate water, 
the territorial seas, impoundment, or tributary periodically overtops 
the berm or other similar feature. Water can also overtop a natural 
berm or artificial dike and flow from the wetland to the water to which 
it is adjacent. As noted above, the Supreme Court has concluded that 
adjacent wetlands under this definition are not limited to only those 
that exist as a result of ``flooding or permeation by water having its 
source in adjacent bodies of open water,'' and that wetlands may affect 
the water quality in adjacent waters even when those waters do not 
actually inundate the wetlands. Riverside Bayview, 474 U.S. at 134-35. 
In addition, river berms, natural levees, and beach dunes are all 
examples of landforms that are formed by natural processes and do not 
isolate adjacent wetlands from the streams, lakes, or tidal waters that 
form them. River berms, natural levees, and the wetlands and waters 
behind them are part of the floodplain. Natural levees are 
discontinuous, and the openings in these levees allow for a hydrologic 
connection to the stream or river and thus the periodic mixing of river 
water and backwater. Beach dunes are formed by tidal or wave action, 
and the wetlands that establish behind them experience a fluctuating 
water table seasonally and yearly in synchrony with sea or lake level 
changes. The terms ``earthen dam,'' ``dike,'' ``berm,'' and ``levee'' 
are used to describe similar constructed structures whose primary 
purpose is to help control flood waters. Such levees and similar 
structures also do not isolate adjacent wetlands.
    In addition, adjacent wetlands separated from a jurisdictional 
water by a natural or man-made \123\ berm serve many of the same 
functions as other adjacent wetlands. There are also other important 
considerations, such as chemical and biological functions provided by 
the wetland. For instance, adjacent waters behind berms can still serve 
important water quality functions, including filtering pollutants and 
sediment before they reach other jurisdictional waters and ultimately a 
paragraph (a)(1) water. Wetlands behind berms, where the system is 
extensive, can help reduce the impacts of storm surges caused by 
hurricanes. Adjacent wetlands separated from jurisdictional waters by 
berms and the like also maintain ecological connection with those 
waters. For example, wetlands behind natural and artificial berms can 
provide important habitat for aquatic and semi-aquatic species that use 
both the wetlands and the nearby water for basic food, shelter, and 
reproductive requirements. Though a berm may reduce habitat functional 
value and may prevent some species from moving back and forth from the 
wetland to the nearby jurisdictional water, many species remain able to 
use both habitats despite the presence of such a berm. In some cases, 
the natural landform or artificial barrier can provide extra refuge 
from predators, for rearing young, or other life cycle needs.
---------------------------------------------------------------------------

    \123\ While the agencies use the phrase ``human-made'' in place 
of ``man-made'' in many instances throughout this preamble, they are 
retaining the phrase ``man-made'' in the regulatory text's 
definition of ``adjacent'' to maintain consistency with the 1986 
regulatory text.
---------------------------------------------------------------------------

    The agencies received a number of comments on the definition of 
``adjacent.'' Many commenters supported the continued use of the well-
established definition, while several commenters suggested that the 
agencies should use only the relatively permanent standard or continue 
the approach to adjacent wetlands that was included in the 2020 NWPR. 
Some commenters critiqued the proposed definition of ``adjacent,'' with 
some stating that the definition was ``overly-broad and ambiguous.'' A 
commenter asserted that the word ``adjacent'' should be given its plain 
meaning for the sake of regulatory certainty, adding that the term 
``neighboring'' within the definition of ``adjacent'' goes ``beyond the 
ordinary understanding'' of adjacency. The agencies disagree with these 
commenters and are finalizing the longstanding definition of 
``adjacent.'' In section IV.A.3.b.ii of this preamble, the agencies 
concluded that the relatively permanent standard is insufficient as the 
sole standard for geographic jurisdiction under the Clean Water Act. 
The 2020 NWPR's limits on the scope of jurisdictional adjacent wetlands 
were based on an interpretation of the relatively permanent standard. 
Therefore, the agencies have concluded that the 2020 NWPR's approach to 
adjacent wetlands is inconsistent with the statute for the same reasons 
the relatively permanent standard is when used as the sole standard. 
The record demonstrates the effects of wetlands on the integrity of 
paragraph (a)(1) waters when they have other types of surface 
connections, such as wetlands that overflow and flood jurisdictional 
waters or wetlands with less frequent surface water connections; 
wetlands with shallow subsurface connections to other protected waters; 
wetlands separated from other protected waters by artificial barriers 
but that lack a direct hydrologic surface connection to those waters in 
a typical year; or other wetlands proximate to jurisdictional waters. 
As discussed in section IV.B.3 of this preamble, within the first year 
of implementation of the 2020 NWPR, 70% of streams and wetlands 
evaluated were found to be non-jurisdictional, including 15,675 
wetlands that did not meet the 2020 NWPR's revised adjacency criteria. 
The substantial increase in waters lacking Federal protection 
compromises the agencies' ability to fulfill the objective of the Clean 
Water Act to protect the integrity of a large swath of the nation's 
waters (see section IV.B.3 of this preamble). Neither Tribal nor State 
regulations have been passed to fill this gap.
    Retaining the longstanding definition of ``adjacent'' is also 
consistent with Riverside Bayview and Justice Kennedy's opinion in 
Rapanos, as well as with scientific information indicating that 
wetlands meeting this definition provide important functions that 
contribute to the integrity of traditional navigable waters, the 
territorial seas, and interstate waters. See section IV.A of this 
preamble.
    The agencies agree with commenters who stated that it is 
appropriate to include wetlands behind natural and artificial berms and 
the like as adjacent wetlands for the reasons discussed in section IV.A 
of this preamble. As noted above, adjacent wetlands behind natural and 
artificial berms can serve important water quality functions, such as 
filtering pollutants and sediment before they reach other 
jurisdictional waters and ultimately paragraph (a)(1) waters, and can 
help reduce the impacts of storm surges caused by hurricanes; see also 
section III.B of the Technical Support Document. The Supreme Court in 
Riverside Bayview deferred to the agencies' interpretation of the Clean

[[Page 3119]]

Water Act to include adjacent wetlands. Riverside Bayview, 474 U.S. at 
135 (``[T]he Corps has concluded that wetlands adjacent to lakes, 
rivers, streams, and other bodies of water may function as integral 
parts of the aquatic environment even when the moisture creating the 
wetlands does not find its source in the adjacent bodies of water. . . 
. [W]e therefore conclude that a definition of `waters of the United 
States' encompassing all wetlands adjacent to other bodies of water 
over which the Corps has jurisdiction is a permissible interpretation 
of the Act.''). Justice Kennedy stated: ``In many cases, moreover, 
filling in wetlands separated from another water by a berm can mean 
that floodwater, impurities, or runoff that would have been stored or 
contained in the wetlands will instead flow out to major waterways. 
With these concerns in mind, the Corps' definition of adjacency is a 
reasonable one, for it may be the absence of an interchange of waters 
prior to the dredge and fill activity that makes protection of the 
wetlands critical to the statutory scheme.'' Rapanos, 547 U.S. at 775.
    The agencies also disagree that regulatory certainty requires 
revision of the definition of adjacent, including deleting the term 
``neighboring.'' Regulatory certainty is provided by the fact that the 
agencies are retaining the definition that has been in place for 
decades and will continue to interpret and implement it as they have 
for decades. In addition, the longstanding regulation properly defines 
the term ``adjacent'' for purposes of the Clean Water Act because it is 
based on the concept of both reasonable proximity and scientific 
connections.
c. High Tide Line
    This rule makes no changes to the definition of ``high tide line'' 
contained in the 1986 regulations (and in the 2020 NWPR, which made no 
changes to the 1986 regulation). The term ``high tide line'' is defined 
as ``the line of intersection of the land with the water's surface at 
the maximum height reached by a rising tide. The high tide line may be 
determined, in the absence of actual data, by a line of oil or scum 
along shore objects, a more or less continuous deposit of fine shell or 
debris on the foreshore or berm, other physical markings or 
characteristics, vegetation lines, tidal gages, or other suitable means 
that delineate the general height reached by a rising tide. The line 
encompasses spring high tides and other high tides that occur with 
periodic frequency but does not include storm surges in which there is 
a departure from the normal or predicted reach of the tide due to the 
piling up of water against a coast by strong winds such as those 
accompanying a hurricane or other intense storm.'' The agencies are not 
amending this definition. This definition has been in place since 1977 
(see 42 FR 37144 (July 19, 1977); 33 CFR 323.3(c) (1978)), and like the 
definitions discussed above, is a well-established definition that is 
familiar to regulators, environmental consultants, and the scientific 
community. This term defines the landward limits of jurisdiction in 
tidal waters when there are no adjacent non-tidal ``waters of the 
United States.'' 51 FR 41206, 41251 (November 13, 1986).
d. Ordinary High Water Mark
    This rule makes no changes to the definition of ``ordinary high 
water mark'' (``OHWM'') contained in the 1986 regulations (and in the 
2020 NWPR, which made no changes to the 1986 regulation). OHWM is 
defined as ``that line on the shore established by the fluctuations of 
water and indicated by physical characteristics such as clear, natural 
line impressed on the bank, shelving, changes in the character of soil, 
destruction of terrestrial vegetation, the presence of litter and 
debris, or other appropriate means that consider the characteristics of 
the surrounding areas.'' 33 CFR 328.3(e) (2014). This term, unchanged 
since 1977, see 41 FR 37144 (July 19, 1977), defines the lateral limits 
of jurisdiction in non-tidal waters, provided the limits of 
jurisdiction are not extended by adjacent wetlands. When adjacent 
wetlands are present, Clean Water Act jurisdiction extends beyond the 
OHWM to the limits of the adjacent wetlands. 33 CFR 328.4; RGL 05-05 at 
1 (December 7, 2005).
e. Tidal Water
    This rule makes no changes to the definition of ``tidal water'' 
contained in the 1986 regulations (and in the 2020 NWPR, which made no 
changes to the 1986 regulation). The term ``tidal water'' is defined as 
``those waters that rise and fall in a predictable and measurable 
rhythm or cycle due to the gravitational pulls of the moon and sun. 
Tidal waters end where the rise and fall of the water surface can no 
longer be practically measured in a predictable rhythm due to masking 
by hydrologic, wind, or other effects.'' Although the term ``tidal 
waters'' was referenced throughout the Corps' 1977 regulations, 
including the preamble (see, e.g., 42 FR 37123, 37128, 37132, 37144, 
37161 (July 19, 1977)), it was not defined in regulations until 1986. 
As explained in the preamble to the 1986 regulations, this definition 
is consistent with the way the Corps has traditionally interpreted the 
term. 51 FR 41217, 41218 (November 13, 1986). The agencies are not 
amending this definition in this rule.
9. Significantly Affect
a. This Rule
    As discussed above, waters are protected by the Clean Water Act 
under this rule if they meet the significant nexus standard; that is, 
they alone, or in combination with other similarly situated waters in 
the region, significantly affect the chemical, physical, or biological 
integrity of the waters identified in paragraph (a)(1) of this rule. 
This rule defines the term ``significantly affect'' for these purposes 
to mean ``a material influence on the chemical, physical, or biological 
integrity of '' a paragraph (a)(1) water. Under this rule, waters, 
including wetlands, are evaluated either alone or in combination with 
other similarly situated waters in the region based on the functions 
the evaluated waters perform. This rule identifies specific functions 
that will be assessed \124\ and identifies specific factors that will 
be considered when determining whether the functions provided by the 
water, alone or in combination, have a material influence on the 
integrity of a traditional navigable water, the territorial seas, or an 
interstate water. Thus, the significant nexus standard concerns the 
effects of waters on paragraph (a)(1) waters; it is not an assessment 
of whether a particular discharge of a pollutant will have an effect on 
a paragraph (a)(1) water, although, of course, contribution of flow and 
the associated transport of pollutants are important functions of 
upstream waters and are identified in the rule. Essentially, this 
provision of the rule provides regulators and the public with a clear 
framework for the significant nexus analysis that will be done on a 
case-specific basis under the rule: (1) the functions that will be 
assessed are clearly identified and constitute the ``nexus'' between 
the waters being assessed and the paragraph (a)(1) water, and (2) the 
logical and practical factors that will be considered to figure out the 
strength, or ``significance,'' of those functions for the integrity of 
the paragraph (a)(1) water are explicitly established.
---------------------------------------------------------------------------

    \124\ The agencies are not requiring the use of ``functional 
assessments'' for significant nexus analyses under this rule; see 
section IV.C.9.c of this preamble for further discussion.
---------------------------------------------------------------------------

    The functions identified in the rule are based on the well-known 
benefits that lakes and ponds, streams, and

[[Page 3120]]

wetlands can provide to paragraph (a)(1) waters. See section IV.A.2.c 
of this preamble. Wetlands, for example, function like natural tubs or 
sponges, storing water and slowly releasing it. This process slows the 
water's momentum and erosive potential, reduces flood heights, and 
allows for groundwater recharge, which contributes baseflow to surface 
water systems during dry periods. An acre of wetland can store 1-1.5 
million gallons of floodwater. After being slowed by a wetland, water 
moves around plants, allowing the suspended sediment to drop out and 
settle to the wetland floor. Nutrients that are dissolved in the water 
are often absorbed by plant roots and microorganisms in the soil. Other 
pollutants stick to soil particles. In many cases, this filtration 
process removes much of the water's nutrient and pollutant load by the 
time it leaves a wetland. Wetlands are also some of the most 
biologically productive natural ecosystems in the world, comparable to 
tropical rain forests and coral reefs in their productivity and the 
diversity of species they support. Abundant vegetation and shallow 
water provide diverse habitats for fish and wildlife. Seventy-five 
percent of commercially harvested fish are wetland-dependent. Add 
shellfish species and that number jumps to 95 percent. Streams are the 
dominant source of water in most rivers, and they also convey water 
into local storage compartments, such as ponds, shallow aquifers, or 
stream banks, that are important sources of water for maintaining 
baseflow in rivers. Discharging pollutants or filling in some lakes and 
ponds, streams, and wetlands reduces the amount of rainwater, runoff, 
and snowmelt the stream network can absorb before flooding. The 
increased volume of water in small streams scours stream channels, 
changing them in a way that promotes further flooding. Such altered 
channels have bigger and more frequent floods. The altered channels are 
also less effective at recharging groundwater, trapping sediment, and 
recycling nutrients. As a result, downstream lakes and rivers have 
poorer water quality, less reliable water flows, and less diverse 
aquatic life. Algal blooms and fish kills can become more common, 
causing problems for commercial and sport fisheries. Recreational uses 
may be compromised. In addition, the excess sediment can be costly, 
requiring additional dredging to clear navigational channels and 
harbors and increasing water filtration costs for municipalities and 
industry. See, e.g., sections I and III of the Technical Support 
Document. So the significant nexus standard is focused on identifying 
those lakes and ponds, streams, and wetlands that provide these well-
understood functions such that they need baseline Federal protections 
under the Clean Water Act in order to protect the integrity of 
traditional navigable waters, the territorial seas, and interstate 
waters. As discussed elsewhere, a determination that a water falls 
within the definition of ``waters of the United States'' does not mean 
that discharges or activities cannot occur in that water. See section 
IV.C.10 of this preamble.
    The functions assessed in this rule are well-known indicators that 
are tied to the chemical, physical, or biological integrity of 
paragraph (a)(1) waters. The functions assessed are: contribution of 
flow; trapping, transformation, filtering, and transport of materials 
(including nutrients, sediment, and other pollutants); retention and 
attenuation of floodwaters and runoff; modulation of temperature in 
paragraph (a)(1) waters; or provision of habitat and food resources for 
aquatic species located in paragraph (a)(1) waters.
    The factors considered in this rule are readily understood criteria 
that influence the types and strength of chemical, physical, or 
biological connections and associated effects on paragraph (a)(1) 
waters. In other words, the factors are site-specific conditions that 
influence the strength of the functions that lakes and ponds, streams, 
and wetlands provide to paragraph (a)(1) waters. These factors include 
the distance from a paragraph (a)(1) water; hydrologic factors, such as 
the frequency, duration, magnitude, timing, and rate of hydrologic 
connections, including shallow subsurface flow; the size, density, or 
number of waters that have been determined to be similarly situated; 
landscape position and geomorphology; and climatological variables such 
as temperature, rainfall, and snowpack. The first two factors 
identified in the regulatory definition are key to a significant nexus 
determination: distance and hydrology. The definition of 
``significantly affect'' is derived from the objective of the Clean 
Water Act and is informed by and consistent with Supreme Court case 
law. It is also informed by the agencies' technical and scientific 
judgment and supported by the best available science regarding the 
functions provided by upstream waters to paragraph (a)(1) waters 
relevant to achieving the Clean Water Act's objective. The significant 
nexus standard in this rule is carefully constructed to fall within the 
bounds of the Clean Water Act. Not all waters subject to evaluation 
under the significant nexus standard will have the requisite connection 
to paragraph (a)(1) waters sufficient to be determined jurisdictional.
    In conducting a significant nexus evaluation, the agencies will 
consider each factor in the rule to evaluate the likely strength of any 
effect of functions on a paragraph (a)(1) water. For example, in 
evaluating a stream, under the first factor, the agencies will consider 
the distance of the stream from the paragraph (a)(1) water. Under the 
second factor, the agencies will consider hydrologic factors, such as 
the amount of water from the stream that reaches the paragraph (a)(1) 
water. Under the third factor, the agencies will consider the size, 
density, or number of similarly situated waters, such as, for example, 
the length, width, and depth of the stream. Under the fourth factor, 
the agencies will evaluate landscape position and geomorphology, such 
as the soil type and slope between the stream and the paragraph (a)(1) 
water. Finally, under the fifth factor, the agencies will evaluate the 
climate in the area of the stream, such as whether high temperatures 
lead to high evaporation rates. After noting the relevant factors, 
agencies will then apply them to the list of functions to determine the 
strength of the functions that the stream provides to the paragraph 
(a)(1) water. As noted above, the first two factors, distance from the 
paragraph (a)(1) water and hydrology, will generally be given the 
greatest weight in the assessment of functions provided.
    The agencies regularly determine that waters do not have the 
requisite significant nexus. First, the standard is limited to 
consideration of effects on traditional navigable waters, the 
territorial seas, and interstate waters. Second, the standard is 
limited to effects only on the three statutorily identified aspects of 
those fundamental waters: chemical, physical, or biological integrity. 
Third, the standard cannot be met by merely speculative or 
insubstantial effects on those aspects of those paragraph (a)(1) 
waters, but rather requires the demonstration of a ``material 
influence.'' In this rule, the agencies have specified that a 
``material influence'' is required for the significant nexus standard 
to be met. The phrase ``material influence'' establishes that the 
agencies will be assessing the influence of the waters either alone or 
in combination on the chemical, physical, or biological integrity of a 
paragraph (a)(1) water and will provide qualitative and/or quantitative 
information and articulate a reasoned basis for determining that the 
waters being

[[Page 3121]]

assessed significantly affect a paragraph (a)(1) water.
    This section of the preamble addresses public comment on the 
definition of ``significantly affect'' and on the agencies' 
interpretation and implementation of the definition. This section then 
provides the agencies' general approach to implementation of the 
definition, including elements of the definition such as ``similarly 
situated'' and ``in the region'' for purposes of a significant nexus 
analysis. Discussion of the agencies' approach to implementation of the 
significant nexus standard for particular categories of waters can be 
found in the sections of this preamble addressing tributaries, adjacent 
wetlands, and paragraph (a)(5) waters. See sections IV.C.4.c, IV.C.5.c, 
and IV.C.6.c of this preamble.
b. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
i. Comments on the Definition of ``Significantly Affect''
    The agencies received numerous comments on the definition of 
``significantly affect,'' including the standard established by the 
definition, and the factors and functions.
    Some commenters asserted that the phrase ``more than speculative or 
insubstantial'' in the proposed rule is open-ended, subjective, broad, 
and could increase the number of jurisdictional waters as compared to 
the pre-2015 regulatory regime. Commenters were concerned that while 
waters that have speculative or insubstantial effects on paragraph 
(a)(1) waters do not meet the significant nexus standard, the proposed 
language was unclear and implied that no additional findings were 
required. In response to public comment, this rule replaces the phrase 
``more than speculative or insubstantial'' effects in the definition of 
``significantly affect.'' Commenters were concerned that while waters 
that have speculative or insubstantial effects on paragraph (a)(1) 
waters do not meet the significant nexus standard, the proposed 
language was unclear and implied that no additional findings were 
required. This rule requires that waters have a ``material influence,'' 
and the agencies have concluded that this term will increase the 
clarity and transparency of this rule.
    The agencies have concluded that this term will increase the 
clarity of this rule. In assessing whether a water meets the 
significant nexus standard, the agencies will continue to examine the 
``influence'' of the subject waters on the paragraph (a)(1) water. And 
the ``influence'' must be ``material''--the agencies must explain why 
the subject waters, either alone or in combination with similarly 
situated waters, matters to the integrity of the paragraph (a)(1) 
water. The word ``material'' also reflects not only that the influence 
is, of course, more than speculative or insubstantial, but that the 
agencies will provide qualitative and/or quantitative information and 
articulate a reasoned basis for determining that a significant nexus 
exists, consistent with longstanding practice. The phrase ``material 
influence'' thus reflects the agencies' longstanding position that 
significant nexus determinations should be supported by the factual 
record, relevant scientific data and information, and available tools. 
And that record, data and information, and tools must show, either 
quantitively or qualitatively based on the five factors, that the 
subject waterbody provides functions that materially influence the 
chemical, physical, or biological integrity of a paragraph (a)(1) 
water. The agencies have provided a number of examples in this section 
of waters that do not have a ``material influence,'' and therefore do 
not meet the significant nexus standard. The agencies will continue to 
document the required findings as part of the administrative record. 
See, for example, direction to field staff under the Rapanos Guidance 
at 11 (``Accordingly, Corps districts and EPA regions shall document in 
the administrative record the available information regarding whether a 
tributary and its adjacent wetlands have a significant nexus with a 
traditional navigable water, including the physical indicators of flow 
in a particular case and available information regarding the functions 
of the tributary and any adjacent wetlands.'').
    Some commenters supported the proposed definition of 
``significantly affect'' as ``more than speculative or insubstantial'' 
effects on paragraph (a)(1) waters. Other commenters asserted that 
``more than speculative or insubstantial'' does not mean an effect is 
significant, and some of these commenters requested that the agencies 
use quantitative or statistical thresholds to determine significance. 
Commenters generally requested clarification on how to determine if 
effects are significant or not. One commenter recommended that waters 
should be considered to ``significantly affect'' downstream 
jurisdictional waters unless a science-based determination shows that 
the effects are so speculative or insubstantial as to not affect the 
integrity of downstream waters. Another commenter recommended that an 
effect should only be significant if it would cause the paragraph 
(a)(1) water to exceed applicable water quality standards.
    The agencies disagree that a quantitative or statistical threshold 
should be required to determine significance for several reasons. 
First, the statute contains no text suggesting that the scope of the 
``waters of the United States'' must be identified based on a 
quantitative or statistical threshold, nor is a quantitative or 
statistical assessment necessary to meet the statutory objective the 
definition is designed to achieve: ``to restore and maintain the 
chemical, physical and biological integrity of the Nation's waters.'' 
33 U.S.C. 1251(a). Second, such an approach would be unworkable given 
the extensive regional differences in water systems and the variability 
of individual waterbodies across the nation. For this reason, the 
agencies have long established the practice of site-specific 
assessment. Third, the appellate courts have not held that the term 
``significant'' for purposes of Clean Water Act jurisdiction requires 
statistical significance or quantitative measurement. See, e.g., Precon 
Dev. Corp., Inc. v. U.S. Army Corps of Eng'rs, 603 Fed. Appx. 149, 151-
52 (4th Cir. 2015) (``Precon II'') (unpublished opinion); Cundiff, 555 
F.3d at 211 (``Though no doubt a district court could find such 
evidence persuasive, the Cundiffs point to nothing--no expert opinion, 
no research report or article, and nothing in any of the various 
Rapanos opinions--to indicate that [laboratory analysis] is the sole 
method by which a significant nexus may be proved . . . .''). The Court 
of Appeals for the Fourth Circuit has noted that the standard ``is a 
`flexibly ecological inquiry,' '' and that ``[q]uantitative or 
qualitative evidence may support [applicability of the CWA].'' Precon 
II, 603 Fed. Appx. at 151-52 (citation omitted). The same court also 
has clarified that the burden of establishing applicability of the 
Clean Water Act should not be ``unreasonable.'' Precon Dev. Corp., Inc. 
v. U.S. Army Corps of Eng'rs, 633 F.3d 278, 297 (4th Cir. 2011) 
(``Precon I''). While the appellate courts have accepted laboratory 
analysis or quantitative or empirical data, see, e.g., United States v. 
Donovan, 661 F.3d 174, 186 (3d Cir. 2011); Northern California River 
Watch v. City of Healdsburg, 496 F.3d 993, 1000-1001 (9th Cir. 2007), 
such quantitative evidence is not required. Precon I, 633 F.3d at 294 
(``We agree that the significant nexus test does

[[Page 3122]]

not require laboratory tests or any particular quantitative 
measurements in order to establish significance.''). The appellate 
courts have accepted a variety of evidence, including but not limited 
to, photographs, visual observation of stream condition, flow and 
morphology, studies, dye tests, scientific literature, maps, aerial 
photographs, and remote sensing data. United States v. Lucas, 516 F.3d 
316, 326-27 (5th Cir. 2008); see also Deerfield Plantation Phase II-B 
Property Owners Ass'n v. U.S. Army Corps of Eng'rs, 501 Fed. Appx. 268, 
270 (4th Cir. 2012) (unpublished opinion) (noting that in addition to 
conducting two site visits, the Corps relied upon infrared aerial 
photography, agency records, a county soil survey, a topographic map, 
and a wetland inventory); Donovan, 661 F.3d at 185-86. As under the 
pre-2015 regulatory regime, the agencies will continue to reasonably 
determine, based on the record before them, if a water, either alone or 
in combination with similarly situated waters in the region, 
significantly affects a paragraph (a)(1) water.
    Some commenters agreed with the agencies that a water may 
constitute ``waters of the United States'' when it significantly 
affects any one form of chemical, physical, or biological integrity of 
a paragraph (a)(1) water. However, other commenters disagreed and 
stated that a water should significantly affect all three forms of 
integrity--chemical, physical, and biological--to be considered 
``waters of the United States.'' Some of these commenters asserted that 
the use of ``or'' has the potential to greatly expand the scope of 
jurisdiction. The agencies disagree that this approach would expand the 
scope of jurisdiction because it is consistent with the pre-2015 
regulatory regime and longstanding practice. The agencies acknowledge 
that Justice Kennedy used the conjunction ``and'' when concluding that 
wetlands possess the requisite significant nexus if the wetlands 
``either alone or in combination with similarly situated [wet]lands in 
the region, significantly affect the chemical, physical, and biological 
integrity of other covered waters more readily understood as 
`navigable.' '' Rapanos, 547 U.S. at 780. However, the agencies 
disagree that the use of the word ``and'' in this context represents a 
holding by Justice Kennedy that only a water that alone or combination 
significantly affects every single aspect of integrity is 
jurisdictional. It is simply not reasonable to read Justice Kennedy's 
opinion to stand for the proposition that a wetland that provides 
important pollutant retention and trapping functions that protect the 
chemical integrity of a paragraph (a)(1) water and also provides 
important benefits for the salmon population of that river is not 
jurisdictional because it does not also significantly affect the 
physical structure of that water. In any case, the agencies are not 
implementing a Supreme Court opinion, but rather are construing the 
Clean Water Act, as informed by relevant Supreme Court opinions. 
Congress intended the Clean Water Act to ``restore and maintain'' all 
three forms of ``integrity,'' section 101(a), so if any one of them is 
compromised, then the statute's stated objective would be contravened. 
It would be contrary to the plain language of the statute and subvert 
the law's objective if the Clean Water Act only protected paragraph 
(a)(1) waters upon a showing that there were effects on every attribute 
of their integrity. This interpretation is consistent with the 
agencies' longstanding position. As the agencies stated in the Rapanos 
Guidance: ``Consistent with Justice Kennedy's instruction, EPA and the 
Corps will apply the significant nexus standard in a manner that 
restores and maintains any of these three attributes of traditional 
navigable waters.'' Rapanos Guidance at 10 & n.35.
    Some commenters stated that the proposed definition of 
``significantly affect'' was too expansive and would allow the agencies 
to assert jurisdiction over any body of water, no matter the size, even 
if connections are remote or scientifically questionable. Some 
commenters asserted that overall, the proposed definition of 
``significantly affect'' was unclear, difficult to understand, and 
provides the agencies with too much discretion to make jurisdictional 
decisions. A couple of these commenters stated that the definition 
would require case-by-case assessments and as a result, the approach 
does not give fair notice to stakeholders of when the Clean Water Act 
applies. The agencies disagree for the reasons outlined below, 
including that this rule's definition of ``significantly affect'' is 
consistent with case law and the science and places appropriate 
limitations on the significant nexus standard.
    The agencies' definition of the term ``significantly affect'' in 
this rule is linked directly to the objective of the Act and to the 
effects upstream waters have on the water quality of paragraph (a)(1) 
waters. The definition is also informed by and consistent with Supreme 
Court case law addressing the scope of ``waters of the United States.'' 
Beginning with Riverside Bayview, the Supreme Court stated that the 
``objective incorporated a broad, systemic view of the goal of 
maintaining and improving water quality: as the House Report on the 
legislation put it, `the word ``integrity'' . . . refers to a condition 
in which the natural structure and function of ecosystems is [are] 
maintained.' H.R. Rep. No. 92-911, p. 76 (1972).'' 474 U.S. at 132. The 
definition of ``significantly affect'' finds further support in the 
Court's conclusion that: ``If it is reasonable for the Corps to 
conclude that in the majority of cases, adjacent wetlands have 
significant effects on water quality and the aquatic ecosystem, its 
definition can stand.'' Id. at 138 n.9. The majority opinion in SWANCC 
introduced the phrase ``significant nexus'' as the concept that 
informed the Court's reading of Clean Water Act jurisdiction over 
waters that are not navigable in fact. 531 U.S. at 167, 172. Based on 
SWANCC, Justice Kennedy's concurrence in Rapanos stated that to 
constitute ``waters of the United States'' covered by the Clean Water 
Act, ``a water or wetland must possess a `significant nexus' to waters 
that are or were navigable in fact or that could reasonably be so 
made.'' 547 U.S. at 759 (Kennedy, J., concurring in the judgment) 
(citing SWANCC, 531 U.S. at 167, 172). And five Justices support 
jurisdiction under Justice Kennedy's conclusion that wetlands possess 
the requisite significant nexus if the wetlands ``either alone or in 
combination with similarly situated [wet]lands in the region, 
significantly affect the chemical, physical, and biological integrity 
of other covered waters more readily understood as `navigable.' '' 547 
U.S. at 780.
    Justice Kennedy's assessment of the facts and the evidence in the 
cases before the justices further inform the scope of this rule's 
definition of ``significantly affect.'' In Rapanos, Justice Kennedy 
stated that in both the consolidated cases before the Court the record 
contained evidence suggesting the possible existence of a significant 
nexus according to the principles he identified. See id. at 783. 
Justice Kennedy concluded that ``the end result in these cases and many 
others to be considered by the Corps may be the same as that suggested 
by the dissent, namely, that the Corps' assertion of jurisdiction is 
valid.'' Id. Justice Kennedy remanded the cases because neither the 
agency nor the reviewing courts applied the proper legal standard. See 
id. Justice Kennedy was clear however, that ``[m]uch the same

[[Page 3123]]

evidence should permit the establishment of a significant nexus with 
navigable-in-fact waters, particularly if supplemented by further 
evidence about the significance of the tributaries to which the 
wetlands are connected.'' Id. at 784.
    With respect to one of the wetlands at issue in the consolidated 
Rapanos cases, Justice Kennedy stated: ``In Carabell, No. 04-1384, the 
record also contains evidence bearing on the jurisdictional inquiry. 
The Corps noted in deciding the administrative appeal that `[b]esides 
the effects on wildlife habitat and water quality, the [district 
office] also noted that the project would have a major, long-term 
detrimental effect on wetlands, flood retention, recreation and 
conservation and overall ecology.' . . . The Corps' evaluation further 
noted that by `eliminat[ing] the potential ability of the wetland to 
act as a sediment catch basin,' the proposed project `would contribute 
to increased runoff and . . . accretion along the drain and further 
downstream in Auvase Creek.' And it observed that increased runoff from 
the site would likely cause downstream areas to `see an increase in 
possible flooding magnitude and frequency.' '' Id. at 785-86 (citations 
omitted). Justice Kennedy also expressed concern that ``[t]he 
conditional language in these assessments--`potential ability,' 
`possible flooding'--could suggest an undue degree of speculation.'' 
Id. at 786. Justice Kennedy's observations regarding the underlying 
case inform this rule's definition of ``significant nexus'': the 
functions and factors established by the definition are consistent with 
those identified as relevant by Justice Kennedy, and the requirement 
that waters have a ``material influence'' on paragraph (a)(1) waters 
ensures that the assessment under the significant nexus standard is 
well-documented and reasonable based on that record.
    This rule's definition of ``significantly affect'' is also 
consistent with the best available information, as summarized in the 
Science Report and the Technical Support Document. See section III.E of 
the Technical Support Document. The Science Report concluded that 
watersheds are integrated at multiple spatial and temporal scales by 
flows of surface water and ground water, transport and transformation 
of physical and chemical materials, and movements of organisms. 
Further, the Science Report stated, although all parts of a watershed 
are connected to some degree--by the hydrologic cycle or dispersal of 
organisms, for example--the degree and downstream effects of those 
connections vary spatially and temporally, and are determined by 
characteristics of the chemical, physical, and biological environments 
and by human activities. Those spatial and temporal variations are 
reflected in the agencies' final rule defining ``significantly affect'' 
to mean ``a material influence,'' in the functions the agencies assess, 
and in the factors they use to consider the strength of those 
functions.
    The agencies have more than a decade of experience implementing the 
significant nexus standard by making determinations of whether a water 
alone or in combination with similarly situated waters in the region 
significantly affects the chemical, physical, or biological integrity 
of a paragraph (a)(1) water. The agencies under the pre-2015 regulatory 
regime routinely conducted case-specific significant nexus analyses and 
in many cases concluded that there was no significant nexus. Based on 
the agencies' experience, many waters under this rule will not have a 
significant nexus to paragraph (a)(1) waters, and thus will not be 
jurisdictional under the Clean Water Act. The agencies also note that 
the vast majority of resources assessed in approved jurisdictional 
determinations under the Rapanos Guidance were not assessed under the 
significant nexus standard. Historically, roughly 12% of resources 
assessed in approved jurisdictional determinations under the Rapanos 
Guidance required a significant nexus analysis. It is the agencies' 
expectation that the number of significant nexus analyses will increase 
under this rule due to the assessment of waters under paragraph (a)(5) 
pursuant to the significant nexus standard, but it is correspondingly 
expected that the percent of resources found to be jurisdictional under 
significant nexus analyses will decrease because generally waters will 
be assessed individually under paragraph (a)(5) to determine if they 
meet the significant nexus standard (see section I.B.3.6 of the 
Economic Analysis for the final rule).
    The agencies disagree that the definition of ``significantly 
affect'' and the associated case-by-case assessments do not give fair 
notice to stakeholders of when the Clean Water Act applies. Because of 
the factual nature of the jurisdictional inquiry, any standard will 
require some case-specific factual determinations. The 2020 NWPR 
acknowledged that ``[a]s to simplicity and clarity, the agencies 
acknowledge that field work may frequently be necessary to verify 
whether a feature is a water of the United States.'' 85 FR 22270 (April 
21, 2020). As the Supreme Court has recently recognized in Maui, the 
scope of Clean Water Act jurisdiction does not easily lend itself to 
bright lines: ``In sum, we recognize that a more absolute position . . 
. may be easier to administer. But, as we have said, those positions 
have consequences that are inconsistent with major congressional 
objectives, as revealed by the statute's language, structure, and 
purposes.'' Maui, 140 S. Ct. at 1477. Like the Court in Maui, the 
agencies have established factors to be used in considering the 
strength of the effects on paragraph (a)(1) waters and have identified 
the functions they will assess in making significant nexus 
determinations under the proposed rule. This definition increases the 
implementability of this rule and is consistent with major 
congressional objectives, as revealed by the statute's language, 
structure, and purposes. This rule also clearly identifies the 
categories of waters subject to assessment under the relatively 
permanent standard and significant nexus standard and those features 
that are excluded from the definition of ``waters of the United 
States.'' See section IV.C.10 of this preamble for additional guidance 
to landowners on jurisdictional determinations.
    Some commenters supported the specific list of factors in the 
proposed rule. Other commenters asserted that the list was broad and 
unclear, and some of these commenters stated that the factors would 
lead to subjective, unpredictable outcomes and lengthy project delays. 
Some commenters addressed specific aspects of the proposed factors. For 
example, some commenters stated that the proposed factor ``distance 
from a paragraph (a)(1) water'' and the proposed factor ``distance from 
a water of the United States'' were redundant. Other commenters 
requested that the agencies add factors on soil and watershed 
characteristics. Some commenters requested specific examples of how the 
factors would be implemented and considered together in a significant 
nexus determination.
    The agencies disagree that the factors listed in the proposed rule 
were broad, subjective, and unclear. However, the agencies have 
modified the factors in response to public comments and to increase 
clarity in this rule. The agencies agree with commenters who asserted 
that distance from ``waters of the United States'' is not necessary to 
include in light of the other factors, such as distance from a 
paragraph (a)(1) water and landscape position and geomorphology, and 
have not included the factor in this rule. In response to

[[Page 3124]]

public comments requesting additional detail on how the factors will be 
applied, the agencies have modified the proposed language on 
``hydrologic factors, including subsurface flow'' in this rule to 
provide additional specificity by referring to ``hydrologic factors, 
such as the frequency, duration, magnitude, timing, and rate of 
hydrologic connections, including shallow subsurface flow.'' The 
agencies added a new factor on ``landscape position and geomorphology'' 
in response to public comments requesting that the agencies consider 
watershed and soil characteristics. Landscape position and 
geomorphology capture characteristics like topography, slope, and soil 
porosity which may, for example, affect the strength of the hydrologic 
or biological connections between the subject waters and a paragraph 
(a)(1) water.
    Some commenters asserted that the proposed factors were only 
related to physical integrity, and requested that the agencies add 
factors that they asserted are related to chemical and biological 
integrity (e.g., water quality parameters, pH, or biological 
indicators). The agencies disagree that the factors are only related to 
physical integrity. The factors in this rule influence the types and 
strength of chemical, physical, or biological connections and 
associated effects that streams, wetlands, and open waters have on 
paragraph (a)(1) waters. As described further in section IV.C.9.c of 
this preamble, in general, identified functions coupled with stronger 
factors increase the likelihood of demonstrating a significant nexus. 
For example, similarly situated waters that have the capacity to trap 
or transform pollutants are more likely to affect the chemical 
integrity of a paragraph (a)(1) water if the similarly situated waters 
are closer to the paragraph (a)(1) water, or if there is a larger 
number or higher density of those similarly situated waters.
    Many commenters on the proposal requested that the agencies add a 
specific list of functions that upstream wetlands and waters can 
provide to paragraph (a)(1) waters to the definition of ``significantly 
affect.'' The commenters differed in whether they thought the list 
should be exhaustive or non-exhaustive, and whether all functions need 
to be demonstrated or just one function needs to be demonstrated to 
support a significant nexus determination. Some commenters supported 
the use of functions listed in the proposed rule from the Rapanos 
Guidance in significant nexus determinations. Some commenters requested 
that the agencies consider additional functions that are based on the 
best available science. Some commenters asserted that when functions 
such as flood storage and pollutant retention result from a lack of 
hydrologic connection, those functions should not be considered in a 
significant nexus analysis.
    The agencies agree that including a list of functions in this rule 
would promote clarity and implementation consistency. The agencies 
selected a list of functions based on the functions identified in the 
Rapanos Guidance discussed in the preamble to the proposed rule, the 
agencies' experience implementing the significant nexus standard, 
public comments on that list of functions, and consideration of the 
best available science. The functions in this rule that can be provided 
by tributaries, wetlands, and open waters are keyed to the chemical, 
physical, and biological integrity of traditional navigable waters, the 
territorial seas, and interstate waters. Additionally, assessment of 
the functions in this rule is consistent with the agencies' 
implementation of the pre-2015 regulatory regime. See Rapanos Guidance 
at 8, 9. The agencies disagree with commenters who asserted that when 
functions such as flood storage and pollutant retention result from a 
lack of hydrologic connection, those functions should not be assessed 
in a significant nexus analysis. Such a rigid, categorical test would 
ignore that, even in the absence of a hydrologic connection, an 
upstream water could still have an important functional relationship to 
a downstream traditional navigable water, the territorial seas, or an 
interstate water, most notably where the upstream water retains 
floodwaters or pollutants that would otherwise flow downstream to the 
traditional navigable water, the territorial seas, or interstate water. 
See Technical Support Document section III.D.1; see also 547 U.S. at 
775 (Kennedy, J., concurring in the judgment) (``[I]t may be the 
absence of an interchange of waters prior to the dredge and fill 
activity that makes protection of the wetlands critical to the 
statutory scheme.'').
    The identification of each of the functions in this rule is 
supported by the best available science. The contribution of flow 
downstream is an important function, as upstream waters can be a 
cumulative source of the majority of the total mean annual flow to 
bigger downstream rivers and waters, including via the recharge of 
baseflow. Streams, wetlands, and open waters contribute surface and 
subsurface water downstream, and are the dominant sources of water in 
most rivers. Contribution of flow can significantly affect the 
integrity of downstream paragraph (a)(1) waters, helping to sustain the 
volume of water in larger waters which also influences the 
concentrations of chemicals within those waters.
    Trapping, transformation, filtering, and transporting materials 
(including nutrients, sediment, and other pollutants) are important 
functions influencing the integrity of paragraph (a)(1) waters. 
Sediment storage and export via streams to downstream waters is 
important for maintaining the physical river network, including the 
formation of channel features. Nutrient recycling in upstream waters 
results in the uptake and transformation of large quantities of 
nitrogen and other nutrients that otherwise would be transported 
directly downstream, thereby decreasing impairments of paragraph (a)(1) 
waters. Streams, wetlands, and open waters also improve water quality 
through the assimilation and sequestration of pollutants, including 
chemical contaminants such as pesticides and metals that can degrade 
the integrity of paragraph (a)(1) waters. Streams can also transport 
excess nutrients, excess sediment, and other pollutants downstream, 
such as the case of the tributaries in the Ohio River and Missouri 
River Basins that transport excess nitrogen downstream that contributes 
to ``dead zones'' in the Gulf of Mexico, or tributaries to the 
Guadalupe, San Joaquin, and Sacramento Rivers contributing contaminated 
mercury sediments from mine operations to San Francisco Bay. 
Contaminants are commonly transported from streams to larger downstream 
rivers bound to sediments.
    Wetlands and small streams are particularly effective at retaining 
and attenuating floodwaters. Streams, wetlands, and open waters affect 
the physical integrity of paragraph (a)(1) waters by retaining large 
volumes of stormwater that could otherwise negatively affect the 
condition or function of those paragraph (a)(1) waters. This retention 
and subsequent slowed release of floodwaters can reduce flood peaks in 
paragraph (a)(1) waters and can also maintain river baseflows in 
paragraph (a)(1) waters by recharging alluvial aquifers.
    Water temperature is critical to the distribution and growth of 
aquatic life in downstream waters, both directly (through its effects 
on organisms) and indirectly (through its effects on other 
physiochemical properties, such as dissolved oxygen and suspended 
solids). For example, water temperature controls metabolism and level 
of

[[Page 3125]]

activity in cold-blooded species like fish, amphibians, and aquatic 
invertebrates. Temperature can also control the amount of dissolved 
oxygen in streams, as colder water holds more dissolved oxygen, which 
fish and other fauna need to breathe. Tributaries provide both cold and 
warm water refuge habitats that are critical for protecting aquatic 
life in downstream paragraph (a)(1) waters. Floodplain wetlands and 
open waters also exert substantial controls on water temperature in the 
downgradient tributary network and ultimately in the paragraph (a)(1) 
water.
    Streams, wetlands, and open waters supply habitat and food 
resources for paragraph (a)(1) waters, such as dissolved and 
particulate organic matter (e.g., leaves, wood), which support 
biological activity throughout the river network. In addition to 
organic matter, streams, wetlands, and open waters can also export 
other food resources downstream, such as aquatic insects that are the 
food source for fish in paragraph (a)(1) waters. The export of organic 
matter and food resources downstream is important to maintaining the 
food webs and thus the biological integrity of paragraph (a)(1) waters. 
Streams, wetlands, and open waters provide life-cycle dependent aquatic 
habitat (such as foraging, feeding, nesting, breeding, spawning, and 
use as a nursery area) for species located in paragraph (a)(1) waters. 
Many species require different habitats for different needs (e.g., 
food, spawning habitat, overwintering habitat), and thus move 
throughout a river network over their life-cycles. For example, to 
protect Pacific and Atlantic salmon in traditional navigable waters 
(and their associated commercial and recreational fishing industries), 
protections must be provided from the headwater streams where the fish 
are born and spawn to the marine waters where they spend most of their 
lives. Additionally, headwater streams can provide refuge habitat when 
adverse conditions exist in the larger waterbodies downstream, enabling 
fish to persist and recolonize downstream areas once conditions have 
improved. These upstream systems form integral components of downstream 
food webs, providing nursery habitat for breeding fish and amphibians, 
colonization opportunities for stream invertebrates, and maturation 
habitat for stream insects, including for species that are critical to 
downstream ecosystem function. The provision of life-cycle dependent 
aquatic habitat for species located in paragraph (a)(1) waters can 
significantly affect the biological integrity of those downstream 
waters.
    It is also important to note that the agencies' significant nexus 
standard in this rule is carefully tailored so that only particular 
types of functions provided by upstream waters can be assessed. 
Wetlands, streams, and open waters are well-known to provide a wide 
variety of functions that translate into ecosystem services. A 
significant nexus analysis, however, is limited to an assessment of 
only those functions identified in this rule that have a nexus to the 
chemical, physical, or biological integrity of paragraph (a)(1) waters. 
Thus, there are some important functions provided by wetlands, 
tributaries, and waters evaluated under paragraph (a)(5) that will not 
be assessed by the agencies when making jurisdictional decisions under 
this rule. For example, for purposes of a jurisdictional analysis under 
the significant nexus standard, the agencies will not be taking into 
account the carbon sequestration benefits that aquatic resources like 
wetlands provide. Provision of habitat for non-aquatic species, such as 
migratory birds, and endemic aquatic species would not be considered as 
part of a significant nexus analysis under this rule.\125\ Furthermore, 
the agencies would not assess soil fertility in terrestrial systems, 
which is enhanced by processes in stream and wetland soils and non-
floodplain wetlands that accumulate sediments, prevent or reduce soil 
erosion, and retain water on the landscape, benefiting soil quality and 
productivity in dry lands. There are also a wide variety of functions 
that streams, wetlands, and open waters provide that translate into 
ecosystem services that benefit society that would not be assessed in a 
significant nexus analysis under this rule. These include provision of 
areas for personal enjoyment (e.g., fishing, hunting, boating, and 
birdwatching areas), ceremonial or religious uses, production of fuel, 
forage, and fibers, extraction of materials (e.g., biofuels, food, such 
as shellfish, vegetables, seeds, nuts, rice), plants for clothes and 
other materials, and medical compounds from wetland and aquatic plants 
or animals. While these types of ecosystem services can contribute to 
the economy, they are not relevant to the chemical, physical, or 
biological integrity of paragraph (a)(1) waters and would not be 
considered in a significant nexus analysis under this rule.
---------------------------------------------------------------------------

    \125\ As this preamble has stated, consideration of biological 
functions such as provision of habitat is relevant for purposes of 
significant nexus determinations under this rule only to the extent 
that the functions provided by tributaries, adjacent wetlands, and 
waters assessed under paragraph (a)(5) significantly affect the 
biological integrity of a paragraph (a)(1) water. For example, to 
protect Pacific and Atlantic salmon in traditional navigable waters 
(and their associated commercial and recreational fishing 
industries), protections must be provided from the headwater streams 
where the fish are born and spawn to the marine waters where they 
spend most of their lives.
---------------------------------------------------------------------------

ii. Comments on Interpretation and Implementation of ``Significantly 
Affect''
    The agencies proposed that waters can significantly affect 
paragraph (a)(1) waters either alone or in combination with similarly 
situated waters in the region. The agencies solicited comment on 
approaches for implementing this rule, including regarding which waters 
are ``similarly situated,'' and thus should be analyzed in combination, 
in the scope of the ``region,'' for purposes of a significant nexus 
analysis. Some commenters asserted that the agencies need to consider 
cumulative impacts of water features and their collective influence on 
downstream waters. These commenters supported aggregating waters as 
part of a significant nexus analysis and provided various suggestions 
for interpreting ``similarly situated'' and ``in the region.'' Some 
commenters stated that the agencies should not aggregate waters as part 
of a significant nexus analysis, asserting that aggregation would lead 
to subjectivity, lack of clarity, implementation challenges, and 
arbitrary outcomes. Some of these commenters did not believe it would 
be appropriate to aggregate features far from a project site with 
features on the project site in assessing impacts on downstream waters. 
Some commenters asserted that the proposed rule would presume that 
virtually the entire tributary system, along with isolated waters and 
wetlands, perform functions in the aggregate that benefit downstream 
waters. Other commenters asserted that aggregation should not be 
expanded beyond the Rapanos Guidance approach, and they expressed 
concern that the proposed rule would aggregate waters more broadly than 
the guidance. Some commenters expressed concern that with an 
aggregation approach to significant nexus, all waters assessed within a 
given region could be determined to be jurisdictional, including waters 
outside the project area. Some of these commenters suggested that the 
agencies would eventually assert jurisdiction across most of the 
country, one watershed at a time.
    The agencies disagree that aggregating waters as part of a 
significant nexus

[[Page 3126]]

analysis is inappropriate. The agencies have retained the language in 
this rule that waters will be assessed either alone or in combination 
with similarly situated waters in the region. See sections IV.C.9.c, 
IV.C.4.c, IV.C.5.c, and IV.C.6.c of this preamble for a discussion on 
the agencies' approach to implementing the significant nexus standard 
for tributaries, adjacent wetlands, and paragraph (a)(5) waters. The 
agencies have also added language to the definition of ``significantly 
affect'' to further clarify that waters will be assessed either alone 
or in combination with similarly situated waters in the region. 
Assessing the functions of identified waters in combination is 
consistent not only with the significant nexus standard, as described 
in section IV.A of this preamble, but with the science demonstrating 
how upstream waters affect downstream waters. Scientists routinely 
analyze the combined effects of groups of waters, aggregating the known 
effect of one water with those of ecologically similar waters in a 
specific geographic area, or to a certain scale. This is because the 
chemical, physical, and biological integrity of downstream waters is 
directly related to the aggregate contribution of upstream waters that 
flow to them, including any tributaries and connected wetlands. As a 
result, the scientific literature and the Science Report consistently 
document that the health of larger downstream waters is directly 
related to the aggregate health of waters located upstream, including 
waters such as wetlands that may not be hydrologically connected but 
function together to mitigate the potential impacts of flooding and 
pollutant contamination on downstream waters. See Technical Support 
Document section III.E.ii.
    The agencies also disagree that the agencies would assert 
jurisdiction too broadly based on the definition of ``significantly 
affect.'' As discussed in section IV.A of this preamble, the agencies 
have carefully crafted a rule that falls within the limitations of the 
statute while achieving the Clean Water Act's objective. Historically, 
only roughly 12% of resources assessed in approved jurisdictional 
determinations under the Rapanos Guidance required a significant nexus 
analysis, and the agencies routinely concluded that waters do not meet 
the significant nexus standard. Based on the agencies' experience, many 
waters assessed under this rule will not have a significant nexus to 
paragraph (a)(1) waters, and thus will not be jurisdictional under the 
Clean Water Act under this rule.
    The following are examples of waters that would likely not be 
jurisdictional under this rule, although the agencies recognize that 
each significant nexus determination is case-specific. Examples of 
waters that would not likely have a significant nexus to paragraph 
(a)(1) waters based on an assessment under this rule of the regulatory 
factors and functions include: a headwater non-relatively permanent 
tributary located within a catchment with no other tributaries and few 
adjacent wetlands in the Eastern United States, which is many miles 
from the paragraph (a)(1) water and contributes low duration, low 
magnitude, and low volume flows downstream; a group of non-relatively 
permanent tributaries and adjacent wetlands located within a closed 
basin in the arid West that does not connect to any paragraph (a)(1) 
water; a non-relatively permanent tributary located within a small 
catchment with another non-relatively permanent tributary and few 
adjacent wetlands in the arid West, which exhibits losing stream 
conditions and capacity to provide only infrequent and very low volume 
flows to the paragraph (a)(1) water; a ditched and straightened non-
relatively permanent tributary with no adjacent wetlands in the 
Southeastern United States that exhibits minimal in-stream or riparian 
habitat value, carries only limited amounts of stormwater from a small 
catchment, and is located miles upstream from the paragraph (a)(1) 
water; a non-adjacent wetland in the Northwestern United States that 
would likely provide only minimal functions to a paragraph (a)(1) water 
given its landscape position in relation to the tributary network and 
the paragraph (a)(1) water; and a non-tributary pond that is 
hydrologically connected to the nearest jurisdictional water only 
during infrequent flooding events but which is miles from the paragraph 
(a)(1) water and would be unlikely to have a material influence on that 
paragraph (a)(1) water. While in most of these examples, the tributary, 
wetland, lake, or pond may well have had some effect on a paragraph 
(a)(1) water, under the hypothetical circumstances described, the 
water(s) would not have a material influence on the chemical, physical, 
or biological integrity of the identified paragraph (a)(1) water, i.e., 
does not significantly affect that water, and therefore the water(s) 
would not be jurisdictional under the Clean Water Act.
    Conversely, the following are examples of waters that would likely 
be jurisdictional under this rule, although again, each significant 
nexus determination is case-specific. Examples include: a second-order 
headwater non-relatively permanent tributary located within a catchment 
with several other tributaries and several adjacent wetlands in the 
Southwestern United States, which are a moderate distance from the 
paragraph (a)(1) water but contribute high magnitude and high volume 
flows downstream during seasonal precipitation events that lead to 
strong effects of the functions on the paragraph (a)(1) water, 
including the transport of large volumes of sediment and woody debris 
that help shape and structure the channel of the paragraph (a)(1) water 
by slowing the flow of water through channels and providing habitat and 
food sources for the fish that live in the paragraph (a)(1) water; a 
non-relatively permanent tributary with several adjacent wetlands in 
the Midwestern United States that provides breeding grounds for fish 
that live in paragraph (a)(1) waters, contributes flows of moderate 
magnitude and moderate volume downstream during frequent precipitation 
events, and is located within a short distance of a paragraph (a)(1) 
water; and an adjacent wetland in the Mountain West that is similarly 
situated with dozens of other adjacent wetlands and several 
tributaries, has the capacity to store high volumes of floodwaters and 
to store and process nutrients that would otherwise reach a downstream 
paragraph (a)(1) water, thereby reducing flooding and the potential for 
algal blooms in the paragraph (a)(1) water, and that provides strong 
functions to a paragraph (a)(1) water given its landscape position in 
relation to the tributary network and the paragraph (a)(1) water. Under 
the hypothetical circumstances described, the water(s) would have a 
material influence on the chemical, physical, or biological integrity 
of the identified paragraph (a)(1) water, i.e., significantly affects 
that water, and therefore the water(s) would be jurisdictional under 
the Clean Water Act.
    The agencies also disagree that any aggregation approach would be 
subjective, unclear, or difficult to implement. The proposed rule 
included alternative options for aggregation (i.e., how to interpret 
``similarly situated'' and ``in the region'') for the public to comment 
upon. After considering public comments, the agencies are providing 
additional information in this preamble to provide clarity regarding 
implementation of ``similarly situated'' and ``in the region'' for 
purposes of aggregating waters as part of a significant nexus analysis. 
Furthermore, the agencies have extensive experience

[[Page 3127]]

aggregating waters under prior regulatory regimes. This preamble 
discusses a variety of tools that are available for identifying waters 
that are similarly situated in the region as part of a significant 
nexus analysis (see, e.g., section IV.C.4.c of this preamble).
    This rule's provision for waters to be assessed either alone, or in 
combination with other similarly situated waters in the region, is 
consistent with the Science Report. An example from the Science Report 
is illustrative. The amount of water or biomass contributed by a 
specific ephemeral stream in a given year might be small, but the 
aggregate contribution of that stream over multiple years, or by all 
ephemeral streams draining that watershed in a given year or over 
multiple years, can have important consequences on the chemical, 
physical, or biological integrity of the downstream waters. Science 
Report at 6-10; see also sections III.A.v and III.E.ii of the Technical 
Support Document. Similarly, the downstream effect of a single event, 
such as pollutant discharge into a single stream or wetland, might be 
negligible but the cumulative effect of multiple discharges could 
degrade the integrity of downstream waters. The Science Report finds, 
``[t]he amount of nutrients removed by any one stream over multiple 
years or by all headwater streams in a watershed in a given year can 
have substantial consequences for downstream waters.'' Science Report 
at 1-11. The cumulative effects of nutrient export from the many small 
headwater streams of the Mississippi River have resulted in large-scale 
ecological and economically harmful impacts hundreds of miles 
downstream, thereby impacting commercial and recreational fisheries in 
the northern Gulf of Mexico.
    Many commenters asserted that the proposed rule was unclear as to 
how the agencies would interpret the ``region'' for purposes of a 
significant nexus analysis. Some of these commenters expressed concern 
that the region would be determined on a case-specific basis, leading 
to regulatory uncertainty. Some commenters asserted that the ``region'' 
should be interpreted narrowly, and many of these commenters opposed 
any expansion of the scope of analysis as compared to the Rapanos 
Guidance. Several commenters stated that a watershed or ecoregion 
approach to interpreting the ``region'' would be too expansive. Many 
commenters supported a watershed approach to interpreting the 
``region,'' with some commenters supporting a large single point of 
entry watershed and other commenters supporting smaller watersheds 
(e.g., hydrologic unit code (HUC) 10 or HUC 12). These commenters 
asserted that a watershed-based approach is consistent with the science 
and would ultimately protect the traditional navigable waters, the 
territorial seas, and interstate waters that are the focus of Clean 
Water Act protections. Some commenters criticized the Rapanos Guidance 
approach for determining the ``region,'' asserting that it was too 
narrow and not based on scientific evidence. Some commenters supported 
an interpretation of ``region'' based on hydrological characteristics 
or geomorphic characteristics, and some of these commenters stated that 
such approaches would allow for the consideration of site-specific 
field data. Other commenters supported an ecoregion-based approach, 
although these commenters differed in the ``level'' of ecoregion sizes 
that they recommended using. As discussed in the implementation section 
below, the agencies have determined that the catchment of the tributary 
is a reasonable and technically appropriate scale for identifying ``in 
the region'' for purposes of the significant nexus standard. The 
catchment is an easily identified and scientifically defensible unit 
for identifying the scope of waters that together may have an effect on 
the chemical, physical, or biological integrity of a particular 
traditional navigable water, the territorial seas, or an interstate 
water.
c. Implementation
    This rule provides increased clarity and substantial guidance to 
assist in implementing the significant nexus standard. The agencies 
have more than a decade of experience implementing the significant 
nexus standard by making determinations of whether a water alone or in 
combination with similarly situated waters in the region significantly 
affects a paragraph (a)(1) water. This section of the preamble provides 
the agencies' general approach to implementing the definition of 
``significantly affect'' for purposes of the significant nexus 
standard. See sections IV.C.4, IV.C.5, and IV.C.6 of this preamble for 
additional information on how the agencies will implement the 
significant nexus standard, including identifying waterbodies on the 
landscape and determining which waters are ``similarly situated'' and 
``in the region.''
i. General Scope of the Significant Nexus Analysis
    Under the significant nexus standard in this rule, the agencies 
must identify the waters that are ``similarly situated'' and the 
``region'' for purposes of determining whether waters ``significantly 
affect'' paragraph (a)(1) waters. The agencies will interpret these 
terms for purposes of this rule in a similar, but not identical, manner 
to the approach to these terms in the Rapanos Guidance. The agencies' 
approach in this rule is based on longstanding practice, the scientific 
support for this rule, and practical implementation considerations.
    The focus of the significant nexus standard is on restoring and 
maintaining the chemical, physical, and biological integrity of 
paragraph (a)(1) waters. Therefore, the agencies have interpreted the 
phrase ``similarly situated'' under pre-2015 practice and will continue 
to interpret that phrase in this rule, in terms of whether waters are 
providing common, or similar, functions for paragraph (a)(1) waters 
such that it is reasonable to consider their effects together. In 
implementing this rule, the agencies will continue their practice under 
the Rapanos Guidance of assessing the flow characteristics and 
functions of tributaries, together with the functions performed by any 
wetlands adjacent to those tributaries, to determine whether 
collectively they have a significant nexus with paragraph (a)(1) 
waters. See Rapanos Guidance at 8. The agencies continue to conclude 
that implementation of ``similarly situated'' to include tributaries 
and their adjacent wetlands in this way is reasonable because of its 
strong scientific foundation--that is, the integral ecological 
relationship between a tributary and its adjacent wetlands. See Rapanos 
Guidance at 10. In considering how to apply the significant nexus 
standard, the agencies have long focused on the integral relationship 
between the ecological characteristics of tributaries and those of 
their adjacent wetlands, which determines in part their contribution to 
restoring and maintaining the chemical, physical, or biological 
integrity of paragraph (a)(1) waters. The ecological relationship 
between tributaries and their adjacent wetlands is well documented in 
the scientific literature and reflects their physical proximity as well 
as shared hydrological and biological characteristics. Id. at 9.
    This approach to implementing similarly situated is also consistent 
with the scientific support for this rule. Stream and wetland 
connectivity to downstream waters, and the resulting effects on the 
integrity of downstream paragraph (a)(1) waters, is best understood and 
assessed when considered cumulatively. One of the main conclusions of 
the Science Report is that the incremental contributions of

[[Page 3128]]

individual streams and wetlands are cumulative across entire 
watersheds, and their effects on downstream waters should be evaluated 
within the context of other streams and wetlands in that watershed. See 
Technical Support Document section III.E.ii and section IV.A of this 
preamble for additional discussion. Furthermore, this approach is clear 
and implementable, and this preamble discusses a variety of tools that 
are available for determining which waters are similarly situated as 
part of a significant nexus analysis. See, e.g., section IV.C.4.c of 
this preamble. See section IV.C.6.c of this preamble for discussion on 
how the agencies intend to implement the significant nexus standard for 
waters assessed under paragraph (a)(5).
    The agencies have identified ``in the region'' for purposes of the 
significant nexus standard in this rule as the catchment of the 
tributary. The catchment is the area of the land surface that drains to 
a specific location for a specific hydrologic feature, in this case the 
tributary. Catchments will be delineated from the downstream-most point 
of the tributary reach of interest and include the area uphill that 
drains to that point. Topography and landscape position influence the 
size and configuration of a catchment. For example, if the tributary of 
interest is East Fork Clear Creek--a second order stream that is a 
tributary that flows indirectly to a traditional navigable water--the 
catchment would be delineated from the point that East Fork Clear Creek 
enters Clear Creek, a third order stream, and include the area uphill 
that drains to that point. The catchment for East Fork Clear Creek 
would include not just East Fork Clear Creek, but also any first order 
streams that flow into East Fork Clear Creek, and these streams would 
be aggregated together along with any wetlands adjacent to the streams 
as part of a significant nexus analysis. As another example, if the 
tributary of interest is Willow Creek--a first order stream that is a 
tributary that flows indirectly to a traditional navigable water--the 
catchment would be delineated from the point that Willow Creek enters a 
second order stream and include the area uphill that drains to that 
point. The catchment would then only include Willow Creek, and Willow 
Creek would be aggregated together along with any adjacent wetlands as 
part of a significant nexus analysis. See discussion of stream order in 
section IV.C.4.c.i of this preamble. The catchment of the tributary of 
interest may contain not just the tributary of interest, but also lower 
order tributaries that are aggregated together along with any adjacent 
wetlands as part of a significant nexus analysis.
    This region (i.e., the catchment of the tributary) for the vast 
majority of tributaries is smaller, and usually substantially smaller, 
than the region identified by the watershed that drains to the nearest 
point of entry of a paragraph (a)(1) water, which was the ``region'' 
used to implement the 2015 Clean Water Rule. While this region is 
generally larger than the region assessed in the Rapanos Guidance under 
which the agencies assessed the relevant reach of a tributary in 
combination with its adjacent wetlands, the catchment is an easily 
identified and scientifically defensible unit for identifying the scope 
of waters that together may have an effect on the chemical, physical, 
or biological integrity of a particular traditional navigable water, 
the territorial seas, or an interstate water. Moreover, the catchment 
is often considered an appropriate spatial unit for water resource 
management. Anthropogenic actions and natural events can have 
widespread effects within the catchment that collectively impact the 
integrity and quality of the relevant paragraph (a)(1) water. The 
functions of the contributing waters are inextricably linked and have a 
cumulative effect on the integrity of the paragraph (a)(1) water. For 
these reasons, it is more appropriate to conduct a significant nexus 
analysis at the catchment scale than to focus on a specific site, such 
as an individual stream segment. In light of the scientific literature, 
the longstanding approach of the agencies' implementation of the Clean 
Water Act, and the statutory goals underpinning Justice Kennedy's 
significant nexus framework, the agencies consider the catchment of the 
tributary to be the appropriate ``region'' for a significant nexus 
analysis. Therefore, all tributaries in a catchment and their adjacent 
wetlands, if any, will be assessed in combination to determine whether 
the significant nexus standard is met.
    For practical administrative purposes, this rule does not require 
evaluation of all similarly situated waters when concluding that those 
waters have a significant nexus to a paragraph (a)(1) water. When an 
identified subset of similarly situated waters provides a sufficient 
science-based justification to conclude presence of a significant 
nexus, for efficiency purposes a significant nexus analysis need not 
require time and resources to locate and analyze all similarly situated 
waters in the entire catchment. For example, if a single waterbody or a 
group of similarly situated waterbodies in a portion of the catchment 
is determined to significantly affect the chemical, physical, or 
biological integrity of a paragraph (a)(1) water, the analysis does not 
have to document all of the similarly situated waterbodies in the 
catchment in order to complete the significant nexus analysis for the 
water(s) subject to the jurisdictional determination. A conclusion that 
a significant nexus is lacking may not, however, be based on 
consideration of some subset of similarly situated waters because under 
the significant nexus standard, the inquiry is how the similarly 
situated waters in combination affect the integrity of the paragraph 
(a)(1) water. Individuals uncertain about the status of waters on their 
property may obtain a jurisdictional determination from the Corps. The 
Corps does not charge a fee for this service. See 33 CFR 325.1; RGL 16-
01 (2016).
ii. Assessing the Functions and Considering the Factors
    In determining whether a water alone or in combination with 
similarly situated waters in the region has a material influence on the 
chemical, physical, or biological integrity of a paragraph (a)(1) 
water, the agencies will assess the functions in paragraph (c)(6)(i) of 
this rule and consider the factors in paragraph (c)(6)(ii) this rule in 
order to reasonably determine jurisdiction based on the record before 
them.\126\ The agencies will consider the factors in this rule to 
analyze the strength of the influence of the functions on paragraph 
(a)(1) waters. In general, functions associated with stronger factors 
increase the likelihood of demonstrating a material influence on 
paragraph (a)(1) waters. For example, when assessing the functions 
provided by the subject waters (and any similarly situated waters) to 
paragraph (a)(1) waters, the agencies would consider whether the 
factors are likely to increase the strength of the influence on the 
paragraph (a)(1) water. Distance from a paragraph (a)(1) water; high 
frequency, magnitude, or duration of hydrologic connections; high 
density of similarly situated waters; landscape position and 
geomorphology translating to a high likelihood of effects on paragraph 
(a)(1) waters; and/or certain climatological variables like rainfall 
patterns leading to more frequent hydrologic connections

[[Page 3129]]

all translate to a higher likelihood of effects on paragraph (a)(1) 
waters. Functions associated with weaker factors decrease the 
likelihood of demonstrating a material influence on paragraph (a)(1) 
waters. For example, when assessing the functions provided by the 
subject waters (and any similarly situated waters) to paragraph (a)(1) 
waters, the agencies would consider whether the factors are likely to 
decrease the strength of the influence on the paragraph (a)(1) water. 
These factors can include a far distance from a paragraph (a)(1) water; 
low frequency, magnitude, or duration of hydrologic connections; low 
density of similarly situated waters; landscape position and 
geomorphology translating to a low likelihood of effects on paragraph 
(a)(1) waters; and/or climatological variables like rainfall patterns 
translating to a low likelihood of effects on paragraph (a)(1) waters. 
Thus, analyses of waters that provide the listed functions to paragraph 
(a)(1) waters, but where only weak factors are present, may not be 
sufficient to demonstrate a material influence. In assessing the 
functions under this rule, if a water, either alone or in combination 
with similarly situated waters in the region, performs one function 
that has a material influence on the integrity of a paragraph (a)(1) 
water, that water would have a significant nexus. The agencies will 
consider all of the factors together when assessing the functions and 
the strength of the influence in the context of each case-specific 
determination of jurisdiction. Consistent with longstanding practice, 
the agencies will make decisions based on best professional judgment 
and on the best available information.
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    \126\ The agencies are not requiring the use of ``functional 
assessment'' methods for significant nexus analyses under this rule. 
``Functional assessment'' methods are used in other regulatory 
contexts, such as for mitigation planning, to explicitly measure the 
strength of functions at the impact site and potential mitigation 
site(s).
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    When assessing the functions and considering the factors in the 
final rule to analyze the influence of subject waters on the integrity 
of paragraph (a)(1) waters, the likelihood of a material influence is 
generally greater with increases in the number or size of the aquatic 
resource or resources being considered, decreasing distance from the 
identified paragraph (a)(1) water, as well as with increased density of 
the waters considered in combination as similarly situated waters. 
However, the agencies also recognize that in watersheds with fewer 
aquatic resources, a smaller number and/or lower density of similarly 
situated waters can provide functions that have disproportionate 
effects on paragraph (a)(1) waters. Hydrologic factors include the 
frequency, duration, magnitude, timing, and rate of hydrologic 
connections, as well as surface and shallow subsurface hydrologic 
connections. The presence of a surface or shallow subsurface hydrologic 
connection, as well as increased frequency, magnitude, or duration of 
such connections, can increase the strength of the functions that the 
subject waters provide to paragraph (a)(1) waters, and the 
corresponding chemical, physical (i.e., hydrologic), or biological 
influence that a water has on paragraph (a)(1) waters. In some 
situations, streams with low duration but a high volume of flow can 
provide strong functions to paragraph (a)(1) waters by transporting 
large volumes of water, sediment, and woody debris that help maintain 
the integrity of those larger waters. A lack of hydrologic connections 
can also in some cases contribute to the strength of effects for 
certain functions such as floodwater attenuation or the retention and 
transformation of nutrients and other pollutants. Landscape position 
and geomorphology provide critical information about the relative 
location of the subject waters being considered within the watershed 
and their spatial relationship to the paragraph (a)(1) water. The 
slope, soil composition and transmissivity, and waterbody substrate 
composition and other physical characteristics (e.g., channel shape) 
can all impact the strength of the functions identified in this rule 
and the associated influence on paragraph (a)(1) waters. Climatological 
factors like temperature, rainfall, and snowpack in a given region can 
influence the strength of the functions provided by the subject waters 
to paragraph (a)(1) waters by affecting the frequency, duration, 
magnitude, timing, and rate of hydrological connections.
    There are ways the agencies can consider a changing climate under 
the significant nexus standard, but only to the extent it is relevant 
to the evaluation of whether the subject waters significantly affect 
the chemical, physical, or biological integrity of paragraph (a)(1) 
waters. For example, a lake that dries up from warming temperatures due 
to climate change and no longer has a surface hydrologic connection to 
downstream waters at the time of assessment might become non-
jurisdictional, whereas another lake that previously had limited 
surface hydrologic connectivity might have increased hydrologic 
connectivity with higher precipitation conditions under a changing 
climate.
    In addition, under the significant nexus standard the agencies can 
consider the functions of streams, wetlands, and open waters that 
support the resilience of the chemical, physical, or biological 
integrity of paragraph (a)(1) waters to climate change. For example, 
more intense and frequent storms and other shifts in precipitation 
cause floods to increase in frequency and volume in some areas of the 
United States. A significant nexus determination can evaluate the 
strength of the effect of runoff storage in wetlands, open waters, and 
headwater tributaries in mitigating increased flood risk associated 
with climate change in paragraph (a)(1) waters. In other areas of the 
country, drought is leading to decreased baseflows in paragraph (a)(1) 
waters. A significant nexus analysis can assess whether the 
transmission of flows into alluvial or regional aquifer storage through 
tributaries and wetlands can mitigate for these climate change-related 
conditions, and assess those benefits to paragraph (a)(1) waters. 
Changes in flow in tributaries caused by climate change will also be 
relevant to the relatively permanent standard, but that standard does 
not allow the agencies to take into account the contribution of 
upstream waters to the resilience of the integrity of downstream 
waters. However, considering on a case-specific basis the strength and 
importance of the functions provided by aquatic resources that 
contribute to the resilience of the integrity of paragraph (a)(1) 
waters to climate change is consistent with the policy and goals of the 
Clean Water Act, case law, and the policy goals of this administration 
as articulated in Executive Order 13990.
    The agencies recognize that there are climate benefits that 
streams, wetlands, and open waters provide that are not related to 
restoring or maintaining the integrity of paragraph (a)(1) waters, such 
as carbon sequestration. Those functions are not considered under this 
rule, because they are not directly related to the chemical, physical, 
or biological integrity of paragraph (a)(1) waters and therefore are 
not relevant to Clean Water Act jurisdiction.
    The record for determinations of jurisdiction (e.g., approved 
jurisdictional determinations for section 404 permits) for waters 
evaluated under the significant nexus standard will include available 
information supporting the determination. In addition to location and 
other descriptive information regarding the water at issue, the record 
will include an explanation of the rationale for the jurisdictional 
conclusion and a description of the information used. Relevant 
information can come from many sources and may in some cases include 
studies of the same type of water or similarly situated waters that 
apply to the water being evaluated. The determination of jurisdiction 
applies

[[Page 3130]]

only to the subject waters located in the area of interest and is a 
case-specific determination based on current conditions (except in the 
case of a potential enforcement action). Any similarly situated waters 
that are part of the significant nexus analysis but that are not in the 
area of interest are not subject to the jurisdictional decision (and so 
would not automatically be deemed jurisdictional or non-
jurisdictional). For example, where the subject water is a portion of a 
tributary reach, the significant nexus analysis would encompass the 
entire tributary reach of the same order, any tributaries within the 
catchment of that reach, and any wetlands adjacent to those 
tributaries. However, the jurisdictional determination would only apply 
to the portion of the tributary reach that is subject to the 
determination.
iii. Tools for a Significant Nexus Analysis
    The agencies have used many tools and sources of information to 
assess significant effects on the chemical, physical, and biological 
integrity of paragraph (a)(1) waters. Some tools and resources that the 
agencies have used to provide and evaluate evidence of a significant 
effect on the physical integrity of paragraph (a)(1) waters include 
USGS stream gage data, floodplain maps, statistical analyses, 
hydrologic models and modeling tools such as USGS's StreamStats or the 
Corps' Hydrologic Engineering Centers River System Analysis System 
(HEC-RAS), physical indicators of flow such as the presence and 
characteristics of a reliable OHWM with a channel defined by bed and 
banks, or other physical indicators of flow including such 
characteristics as shelving, wracking, water staining, sediment 
sorting, and scour, information from NRCS soil surveys, precipitation 
and rainfall data, and NRCS snow telemetry (SNOTEL) data or NOAA 
national snow analyses maps.
    To evaluate the evidence of a significant effect on the biological 
integrity of paragraph (a)(1) waters, the agencies and practitioners 
have used tools and resources such as: population survey data and 
reports from Federal, Tribal, and State resource agencies, natural 
history museum collections databases, bioassessment program databases, 
fish passage inventories, U.S. Fish and Wildlife Service (FWS) Critical 
Habitat layers, species distribution models, and scientific literature 
and references from studies pertinent to the distribution and natural 
history of the species under consideration.
    Tools and resources that can provide and evaluate evidence of a 
significant effect on the chemical integrity of paragraph (a)(1) waters 
include data from USGS water quality monitoring stations; Tribal, 
State, and local water quality reports; water quality monitoring and 
assessment databases; EPA's How's My Waterway (available at https://www.epa.gov/waterdata/hows-my-waterway), which identifies Clean Water 
Act section 303(d) listed waters, water quality impairments, and total 
maximum daily loads; watershed studies; stormwater runoff data or 
models; EPA's NEPAssist (available at https://www.epa.gov/nepa/nepassist), which provides locations and information on wastewater 
discharge facilities and hazardous-waste sites; the National Land Cover 
Database (NLCD); and scientific literature and references from studies 
pertinent to the parameters being reviewed. EPA has developed a web-
based interactive water quality and quantity modeling system 
(Hydrologic and Water Quality System, HAWQS, available at https://www.epa.gov/waterdata/hawqs-hydrologic-and-water-quality-system) that 
is being used to assess the cumulative effects of wetlands on the 
larger waters to which they drain. Additional approaches to quantifying 
the hydrologic storage capacity of wetlands include statistical models, 
such as pairing LIDAR-based topography with precipitation totals. Both 
statistical and process-based models have been used to quantify the 
nutrient removal capacities of non-floodplain wetlands, and in some 
cases to assess the effects of non-floodplain wetland nutrient removal, 
retention, or transformation on downstream water quality. Evaluations 
of a significant effect on the chemical integrity of a paragraph (a)(1) 
water may include qualitative reviews of available information or 
incorporate quantitative analysis components including predictive 
transport modeling.
10. Guidance for Landowners on How To Know When Clean Water Act Permits 
are Required
    The agencies understand that landowners would like to be able to 
easily discern whether their property contains any ``waters of the 
United States'' such that they may need to apply for a relevant Clean 
Water Act permit. With this rule, the agencies strive to provide 
additional clarity for the public. To that end, the rule clearly 
excludes some waters from Clean Water Act jurisdiction, thereby 
narrowing the category of waters that require additional jurisdictional 
analysis. The rule also clearly identifies some categories of waters as 
jurisdictional by rule without the need for further analysis. For the 
small percentage of waters that are not categorically excluded from, or 
included in, Clean Water Act jurisdiction, and which do not meet the 
relatively permanent standard, the agencies have established a new 
regulatory provision defining the meaning of ``significantly affect'' 
to guide implementation of the significant nexus standard. This 
provision provides the public with a clearer picture of the functions 
the agencies will assess and the factors the agencies will consider in 
determining whether waters being analyzed ``significantly affect'' 
(i.e., have a material influence on) the integrity of traditional 
navigable waters, the territorial seas, or interstate waters and 
therefore meet the rule's definition of ``waters of the United 
States.''
    Recognizing the concerns of landowners, the discussion below is 
designed to bring together information from the statute, the final 
rule's text, and this preamble--including the many useful tools 
identified in this preamble--to provide individual landowners with the 
step-by-step information needed to make informed decisions.\127\ In 
addition, as discussed further below, the Corps has established a 
process for landowners to request an official determination of whether 
or not there are ``waters of the United States'' on their property. The 
Corps does not charge a fee for this service.\128\ In cases where a 
landowner seeks to undertake an activity that involves discharges of 
dredged or fill material into areas that are ``waters of the United 
States'' that is not exempt from the permit requirements of the Clean 
Water Act, this section provides information about some of the general 
permits the Corps \129\ has established that allow certain activities 
to proceed with little or no delay if the general conditions and any 
special conditions for the permit are met. Lastly, this section 
provides information for those rare occasions when a landowner needs an 
individual section 404 permit for an activity regulated under that 
section of the Clean Water Act.
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    \127\ See also https://www.epa.gov/wotus for the latest 
information on implementation of the definition of ``waters of the 
United States.''
    \128\ To obtain a speedier determination, some landowners choose 
to incur some expense in providing site information supporting the 
jurisdictional determination request, such as a delineation of the 
lake or pond, stream, or wetland.
    \129\ The agencies note that New Jersey, Michigan, and Florida 
have assumed administration of section 404 programs for certain 
waters in those States under section 404(g) of the Act.

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[[Page 3131]]

    Step 1: Is the activity I want to take on my property exempt from 
needing a Clean Water Act permit?
    Not all activities in or discharges to ``waters of the United 
States'' require authorization under the Clean Water Act. Generally, 
section 402 or section 404 permits are required if a person is 
discharging, or adding, a ``pollutant'' from a ``point source'' to the 
``waters of the United States.'' The terms ``discharge of a 
pollutant,'' ``pollutant,'' and ``point source'' all have specific 
definitions in the Clean Water Act that must be met for the Act's 
requirements to apply. Even if a landowner is discharging a 
``pollutant'' from a ``point source,'' those discharges still may not 
require a Clean Water Act permit because the statute and the agencies' 
regulations exempt some types of discharges from permitting under 
section 404 (for dredged and fill material) and section 402 (for other 
pollutants).
    If a landowner wants to dredge or fill ``waters of the United 
States,'' many activities are exempt from the Clean Water Act's section 
404 permitting requirements,\130\ including:
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    \130\ Note, however, that Clean Water Act section 404(f) 
establishes circumstances (based on certain effects on ``waters of 
the United States'') under which an activity listed as exempt is no 
longer exempt. For more detail, see section 404(f) and the 
regulations on ``discharges not requiring a permit'' at 33 CFR 
323.4.
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     Established (ongoing) farming, ranching, and silviculture 
activities such as plowing, seeding, cultivating, minor drainage, 
harvesting for the production of food, fiber, and forest products, or 
upland soil and water conservation practices;
     Maintenance (but not construction) of drainage ditches;
     Construction and maintenance of irrigation ditches;
     Construction and maintenance of farm or stock ponds;
     Construction and maintenance of farm and forest roads, in 
accordance with best management practices; and
     Maintenance of structures such as dams, dikes, and levees.
    Additionally, many discharges of pollutants other than dredged or 
fill material do not require section 402 permits: \131\
---------------------------------------------------------------------------

    \131\ See 40 CFR 122.3 for the regulatory provisions.
---------------------------------------------------------------------------

     Any discharge of sewage from vessels, effluent from 
properly functioning marine engines, laundry, shower, and galley sink 
wastes, or any other discharge incidental to the normal operation of a 
vessel;
     Any introduction of pollutants from nonpoint-source 
agricultural and silvicultural activities, including storm water runoff 
from orchards, cultivated crops, pastures, range lands, and forest 
lands;
     Return flows from irrigated agriculture; and
     Discharges from a water transfer.
    Step 2: Is water on my property covered by this rule?
    The Clean Water Act does not cover every geographic feature with 
water in it; nor does it subject all activities in waters meeting the 
definition of ``waters of the United States'' to regulation (as 
discussed in Step 1). Puddles may periodically contain water, but they 
are not lakes, ponds, streams, or wetlands and they are not ``waters of 
the United States.'' The rule also has a well-established, very 
specific, three-factor definition of wetlands. That definition requires 
the presence of particular wetland hydrology, soils, and vegetation. 
Therefore, a homeowner's backyard that is soggy only immediately after 
a rainstorm is not ``waters of the United States'' under the rule.
    Some waters are always jurisdictional under the rule: traditional 
navigable waters, the territorial seas, and interstate waters. Lakes 
and ponds, streams (including certain ditches), and wetlands that are 
not always jurisdictional under paragraph (a)(1) of the rule require 
additional assessment to determine whether they are ``waters of the 
United States'' under other categories of the rule. This additional 
assessment follows longstanding principles.
    If a landowner's property does not contain the types of waters, 
including wetlands, covered by this rule, it is not jurisdictional.
    Step 3: Is the water on my property excluded from the definition of 
``waters of the United States''?
    In evaluating whether a water, including a wetland, on a 
landowner's property is covered by the Clean Water Act, first determine 
whether it fits into one of this rule's categorical exclusions. The 
rule excludes certain features that commonly contain water but are not 
``waters of the United States'' (so long as the features are not the 
types of waters that are always jurisdictional--traditional navigable 
waters, the territorial seas, and interstate waters):
     prior converted cropland;
     ditches (including roadside ditches) excavated wholly in 
and draining only dry land and that do not carry a relatively permanent 
flow of water;
     artificially irrigated areas that would revert to dry land 
if the irrigation ceased;
     artificial lakes or ponds created by excavating or diking 
dry land to collect and retain water and which are used exclusively for 
such purposes as stock watering, irrigation, settling basins, or rice 
growing;
     artificial reflecting or swimming pools or other small 
ornamental bodies of water created by excavating or diking dry land to 
retain water for primarily aesthetic reasons;
     waterfilled depressions created in dry land incidental to 
construction activity and pits excavated in dry land for the purpose of 
obtaining fill, sand, or gravel unless and until the construction or 
excavation operation is abandoned and the resulting body of water meets 
the definition of ``waters of the United States'';
     swales and erosional features (e.g., gullies, small 
washes) characterized by low volume, infrequent, or short duration 
flow; and
     waste treatment systems, including treatment ponds or 
lagoons, designed to meet the requirements of the Clean Water Act.
    These exclusions are discussed in more detail in section IV.C.7 of 
this preamble.
    Where a feature located on a landowner's property satisfies the 
terms of an exclusion, it is not jurisdictional under the Clean Water 
Act. That is the case even where the feature would otherwise be 
jurisdictional as an impoundment; tributary; adjacent wetland; or 
intrastate lake or pond, stream, or wetland under this rule.
    Step 4: If the activity I want to undertake on my property is not 
exempt from permitting requirements, and the feature on my property is 
likely a water for purposes of the rule (and is not covered by one of 
the exclusions), what do I do next?
    If the feature on a landowner's property is likely a geographic 
feature considered to be a water, including a wetland, for purposes of 
the rule and is not covered by one of the exclusions, the next step is 
to determine if the water is a ``water of the United States'' under one 
of the longstanding categories in the rule: (1) traditional navigable 
waters, the territorial seas, and interstate waters; (2) jurisdictional 
impoundments of ``waters of the United States''; (3) jurisdictional 
tributaries; (4) jurisdictional adjacent wetlands; and (5) intrastate 
lakes and ponds, streams, or wetlands not identified in paragraphs 
(a)(1) through (4) of the rule that meet either the relatively 
permanent standard or the significant nexus standard.
    This preamble identifies publicly available tools and resources to 
assist landowners in understanding the jurisdictional status of waters, 
including tributaries and wetlands, that may be

[[Page 3132]]

present on their lands. At the same time, the agencies recognize there 
are circumstances under which it may be difficult for an individual 
landowner to determine on their own whether a water on their land is 
jurisdictional. This section can help landowners to conclude whether a 
water on their land is likely to be jurisdictional; if landowners want 
certainty, they can ask the Corps for an approved jurisdictional 
determination. The Corps does not charge a fee for this service. 
Alternatively, as discussed below, some of these activities are readily 
authorized under a nationwide or regional general permit issued by the 
Corps. A landowner does not need an approved jurisdictional 
determination for an activity authorized by a general permit.
(1) Traditional Navigable Waters, the Territorial Seas, and Interstate 
Waters
    Traditional navigable waters, the territorial seas, and interstate 
waters are always jurisdictional. Section IV.C.2. of this preamble 
explains how the agencies will identify these waters.
(2) Jurisdictional Impoundments of ``Waters of the United States''
    Impoundments are distinguishable from natural lakes and ponds 
because they are created by discrete structures (often human-built) 
like dams or levees that typically have the effect of raising the water 
surface elevation, creating or expanding the area of open water, or 
both. Impoundments can be natural (like beaver ponds) or artificial 
(like reservoirs). Under the rule, jurisdictional impoundments include 
(1) impoundments created by impounding one of the ``waters of United 
States'' that was jurisdictional under this rule's definition at the 
time the impoundment was created, and (2) impoundments of waters that 
at the time of assessment meet the definition of ``waters of the United 
States'' under the rule as a traditional navigable water, the 
territorial seas, interstate water, jurisdictional tributary, or 
jurisdictional adjacent wetland, regardless of the water's 
jurisdictional status at the time the impoundment was created. Section 
IV.C.3 of this preamble explains how the agencies will identify 
jurisdictional impoundments.
(3) Jurisdictional Tributaries
    The agencies understand that it can be confusing to determine if 
certain waters and features are tributaries, and whether those 
tributaries are ``waters of the United States.'' It can be especially 
confusing if waters or features on a landowner's property are 
periodically dry--some examples include washes, swales, and ephemeral 
streams. So how can a landowner determine whether features like this 
are jurisdictional?
    The first question is whether the water or feature on a landowner's 
property is excluded as an erosional feature or is potentially 
jurisdictional as a stream. Section IV.C.7.c.ii.3 of this preamble 
discusses the distinctions between excluded erosional features like 
swales, washes, and gullies and potentially jurisdictional streams. So, 
for example, a water would be a stream, not an excluded erosional 
feature, if the water has a defined channel and an indicator of an 
ordinary high water mark such as a natural line impressed on the 
bank.\132\
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    \132\ The Corps has useful guidance on how to identify an 
ordinary high water mark, including Regulatory Guidance Letter 05-
05, ``Ordinary High Water Mark'' (available at https://www.nap.usace.army.mil/Portals/39/docs/regulatory/rgls/rgl05-05.pdf).
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    If the water is determined to be a stream, the next question is 
whether that stream is part of the tributary system of a traditional 
navigable water, the territorial seas, or an interstate water. For 
tools that can help a landowner make this determination, see Step 5, 
below. If it is part of such a tributary system, the final question is 
whether it satisfies either the relatively permanent standard or the 
significant nexus standard under this rule. See section IV.C.4.c of 
this preamble for additional information on how to apply these 
standards. Also, the landowner can ask the Corps to determine whether 
the feature on their property is jurisdictional as discussed further 
below.
    The agencies recognize that it can be confusing that streams with 
less than relatively permanent flow, which often look dry, can be 
``waters of the United States.'' But such streams, where they meet the 
significant nexus standard, are important parts of the ecological 
system that sustains traditional navigable waters, the territorial 
seas, and interstate waters. For example, while almost all the streams 
in Arizona regularly do not have water in them, they are essential to 
the flow in downstream waters, like the Colorado River. Similarly, 
headwater ephemeral streams in the forests of the Northeastern United 
States are essential to flow in downstream rivers. Filling ephemeral 
streams could cause significant harm to the downstream rivers. The 
importance of ephemeral streams is evident from videos of these streams 
flowing after rain events in the Southwest. This video \133\ also 
highlights the difference between dry land and ephemeral tributaries 
and demonstrates why landowners would not want to construct a building 
in an ephemeral stream.
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    \133\ U.S. Department of Agriculture, Agricultural Research 
Service, Multiflume Runoff Event August 1, 1990, https://www.tucson.ars.ag.gov/unit/WGWebcam/WalnutGulchWebcam.htm.
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(4) Jurisdictional Adjacent Wetlands
    The rule uses the same definition of ``adjacent'' that has been 
used by the agencies for the past 45 years: \134\ adjacent means 
bordering, contiguous, or neighboring. The agencies have long used 
three criteria to identify wetlands that are adjacent. These criteria 
are: (1) the wetland has an unbroken surface or shallow subsurface 
connection to a jurisdictional water; (2) the wetland is separated from 
a jurisdictional water by an artificial dike, natural berm, or the 
like; or (3) the wetland is reasonably close to a jurisdictional water. 
There is an extensive discussion of how the agencies will implement 
these criteria in section IV.C.5.c of this preamble. The agencies have 
not established a specific distance limitation in the rule beyond which 
wetlands are never adjacent, but nearly 45 years of implementation of 
this definition shows in a substantial number of cases, adjacent 
wetlands abut (touch) a jurisdictional water. And, on the whole, 
nationwide, adjacent wetlands are within a few hundred feet from 
jurisdictional waters (and in the instances where the distance is 
greater than a few hundred feet, adjacency is likely supported by a 
pipe, non-jurisdictional ditch, karst geology, or some other feature 
that connects the wetland directly to the jurisdictional water).
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    \134\ The 2020 NWPR had a different definition and was in effect 
from June 22, 2020 (in all jurisdictions except Colorado, where the 
rule did not go into effect until April 26, 2021) to August 30, 
2021, when the rule was vacated by the Arizona district court. The 
2015 Clean Water Rule had the same definition of ``adjacent'' but 
added a definition of ``neighboring.''
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    Examples of ``adjacent'' wetlands include wetlands that touch 
jurisdictional tributaries. If the wetland is only separated from the 
jurisdictional tributary by a levee, it is adjacent. If there is a 
barrier, like a river berm or a dike, between the wetland and a 
jurisdictional tributary, for example, the wetland still meets the 
definition of ``adjacent.'' If the wetland is connected to a 
jurisdictional tributary by a ditch that is not jurisdictional, the 
wetland is adjacent.
    If your property contains a ``wetland'' and it is ``adjacent'' it 
must also meet one of the rule's jurisdictional tests. Wetlands that 
are themselves traditional navigable waters, interstate waters, or are 
``adjacent'' to such waters are ``waters of the United States'' by 
rule.

[[Page 3133]]

This includes, for example, tidal marshes along the Atlantic Coast that 
are subject to the ebb and flow of the tide and therefore are 
traditional navigable waters, wetlands that are separated from the 
Mississippi River from levees, and the Great Dismal Swamp, a wetland 
which crosses the border between Virginia and North Carolina. Other 
``adjacent'' wetlands are only ``waters of the United States'' if they 
satisfy either the relatively permanent standard or the significant 
nexus standard.
(5) Jurisdictional Intrastate Lakes and Ponds, Streams, or Wetlands Not 
Identified in Paragraphs (a)(1) Through (4) of the Rule
    The rule defines ``waters of the United States'' to include 
``intrastate lakes and ponds, streams, or wetlands not identified in 
paragraphs (a)(1) through (4)'' that meet either the relatively 
permanent standard or the significant nexus standard. The agencies 
intend to identify relatively permanent waters under this provision 
using a similar approach to the one described for relatively permanent 
tributaries in section IV.C.4.c.ii of this preamble. In implementing 
the significant nexus standard, the agencies generally intend to 
analyze these waters individually to determine if they significantly 
affect the chemical, physical, or biological integrity of a paragraph 
(a)(1) water. One example of the kind of water that is likely to be 
assessed under this provision is a lake that is close to a 
jurisdictional tributary or traditional navigable water, the 
territorial seas, or an interstate water, but that is not part of the 
tributary system; this is because the adjacency provision in the rule 
(and in the longstanding regulations) applies only to wetlands, not to 
lakes and ponds.
    Step 5: Are there resources and sources of help from the agencies 
to aid me in this process?
    Yes, in addition to the rule and preamble, the agencies have 
identified several other types of resources to help landowners in the 
jurisdictional and permitting process. First, the agencies have 
identified a number of publicly available, user-friendly tools and 
resources for landowners seeking more information about whether their 
property contains ``waters of the United States.'' Next, the Corps has 
established a process for landowners to request an official 
determination of whether or not there are ``waters of the United 
States'' on their property. Finally, in cases where a landowner is 
undertaking an activity that is not exempt from the permit requirements 
of the Clean Water Act and their land contains waters that are likely 
to be or that the Corps has determined to be ``waters of the United 
States,'' this section provides information about some of the general 
permits the Corps has established that allow certain activities to 
proceed with little or no delay if the general and any special 
conditions for the permit are met. In addition, EPA and authorized 
states have established general permits for a wide variety of 
discharges subject to permitting under section 402 that have minimal 
impacts to waters. Finally, this section also provides information on 
those rare occasions when a landowner needs an individual Clean Water 
Act section 404 permit.
(1) Are there any publicly available tools and resources to help me get 
more information about waters on my land?
    This preamble includes an extensive discussion of the many tools 
and resources the agencies can use when making jurisdictional 
determinations. It also discusses publicly available resources that 
provide jurisdictional and permit information. See sections IV.G and H 
of this preamble. Some of these publicly available tools and resources 
may be particularly useful for landowners seeking more information 
about whether their property might contain ``waters of the United 
States.'' For example, EPA's Clean Water Act Approved Jurisdictional 
Determination website (available at https://watersgeo.epa.gov/cwa/CWA-JDs/) includes a map viewer that shows where waters have been 
determined to be jurisdictional or non-jurisdictional based on approved 
jurisdictional determinations. Users can quickly and easily input a 
location (e.g., a city and State, or a latitude and longitude) to view 
approved jurisdictional determinations that have been finalized in a 
specific geographic area. Additionally, publicly available map viewers 
integrate datasets, allowing users to consolidate and evaluate relevant 
data from multiple sources in one visual platform. EPA's EnviroAtlas 
(available at https://www.epa.gov/enviroatlas/enviroatlas-interactive-map) is a map viewer that provides information and interpretative tools 
to help facilitate surface water assessments using multiple data layers 
such as land cover, stream hydrography, soils, and topography. Users 
can quickly and easily input a location (e.g., a city and State, or a 
latitude and longitude) and select relevant map layers from a list of 
individual datasets and indices. The EPA Watershed Assessment, 
Tracking, and Environmental Results System (WATERS) Geoviewer 
(available at https://www.epa.gov/waterdata/waters-geoviewer) provides 
many map layers, including water map layers like NHDPlus, and watershed 
reports for analysis and interpretation. Similarly, in the USGS 
National Map Viewer (available at https://apps.nationalmap.gov/viewer/) 
users can view different map layers, including aerial imagery, water 
map layers like the NHD and NHDPlus High Resolution, wetlands map 
layers like NWI, and land cover, elevation data, and topographic maps. 
EPA's How's My Waterway mapper (available at https://mywaterway.epa.gov/) provides users with information about the water 
quality of their local waterways, including information about water 
quality impairments and section 402 permitted dischargers.
(2) How can I obtain a jurisdictional determination for a water on my 
property?
    The Corps has long provided jurisdictional determinations as a 
public service. The Corps does not charge a fee for this service. There 
are two types of jurisdictional determinations provided by the Corps: 
approved jurisdictional determinations and preliminary jurisdictional 
determinations. An approved jurisdictional determination is a Corps 
document stating the presence or absence of waters of the United States 
on a parcel or a written statement and map identifying the limits of 
waters of the United States on a parcel. A preliminary jurisdictional 
determination is a document indicating that there may be waters of the 
United States on a parcel or indications of the approximate location(s) 
of waters of the United States on a parcel. The Corps recognizes the 
value of jurisdictional determinations to the public and reaffirms the 
Corps' commitment to continue its practice of providing jurisdictional 
determinations, for which it does not charge a fee, upon request. A 
landowner who would like to know whether areas on their property meet 
the definition of ``waters of the United States'' may contact their 
local Corps district regulatory office at any time. The list of local 
district regulatory offices is available at the following link: https://www.usace.army.mil/Missions/Locations/. Contact information is 
available at the link for each local office.
    When a local district regulatory office is contacted, district 
personnel will ensure that the landowner understands the different 
types of jurisdictional determinations so the landowner can make an 
informed decision about which type of jurisdictional determination is 
most appropriate for the landowner's circumstances. See section 
III.A.1.b of this preamble for a discussion of the

[[Page 3134]]

types of jurisdictional determinations the Corps issues. Once the 
landowner determines the best option for their particular circumstance, 
it is the Corps' policy to honor the request unless it is 
impracticable.
    The Corps may need to conduct one or more site visits to collect 
information when a landowner requests an approved or preliminary 
jurisdictional determination. In addition to information collected 
during the site visit(s), the Corps will use data from other resources 
(such as those described in this preamble) as well as any information 
the landowner wishes to provide to inform the jurisdictional 
determination. A landowner may choose to hire an environmental 
consultant who can assist by providing site evaluation information and 
data collection, thereby supporting a more efficient process. Once the 
Corps has completed the jurisdictional determination, they will provide 
it to the landowner in a letter.
    If the jurisdictional determination is an approved jurisdictional 
determination, the letter from the Corps will typically include one or 
more approved jurisdictional determination forms that explain the basis 
for the determination that the aquatic resources on the landowner's 
property are or are not ``waters of the United States.'' The landowner 
will also receive a form to request an appeal of the approved 
jurisdictional determination. Consistent with Regulatory Guidance 
Letter 05-02, ``Expiration of Geographic Jurisdictional Determinations 
of `Waters of the United States,''' the landowner can rely upon the 
approved jurisdictional determination until it expires unless new 
information warrants revision of the approved jurisdictional 
determination prior to its expiration.
    If the landowner disagrees with the Corps' approved jurisdictional 
determination, the landowner can request that it be reconsidered and 
submit any available new information or data to the district. If, after 
such reconsideration, or in the absence of any new information, the 
landowner disagrees with the approved jurisdictional determination, the 
landowner may administratively appeal the decision by sending a 
completed Request for Administrative Appeal form to the appropriate 
Corps' division office. The Corps' regulations at 33 CFR part 331 
describe the administrative appeal process. The Corps' division may 
determine that none of the reasons for appeal have merit, in which case 
the approved jurisdictional determination remains in effect until it 
expires or it is revised by the Corps district. Alternatively, the 
Corps' division may determine that one or more of the reasons for 
appeal have merit in which case the approved jurisdictional 
determination is remanded to the district for reconsideration. The 
landowner may also challenge the approved jurisdictional determination 
in Federal district court.\135\
---------------------------------------------------------------------------

    \135\ In U.S. Army Corps of Engineers v. Hawkes Co., 136 S. Ct. 
1807 (2016), the Supreme Court held that approved jurisdictional 
determinations are subject to judicial review.
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(3) Are there general permits under section 404 of the Clean Water Act 
for individual landowners? How do I obtain coverage under a nationwide 
permit?
    Landowners that wish to pursue activities that are or may be 
subject to the permit requirements of the Clean Water Act and that will 
impact ``waters of the United States'' on their property may be able to 
obtain coverage under a general permit. General permits are issued on a 
nationwide, regional, or statewide basis for particular categories of 
activities that result in no more than minimal individual or cumulative 
adverse environmental effects. While some general permits require the 
applicant to submit a pre-construction notification to the Corps or a 
State, others allow the project proponent to proceed with the 
authorized activity with no formal notification. The general permit 
process allows certain activities to proceed with little or no delay if 
the conditions of the general permit are met. For example, minor road 
construction activities, utility line backfill, and minor discharges 
for maintenance can be authorized by a general permit, where the 
activity meets the acreage limits and other limits specified in the 
general permit.
    As of the date of this rule, the Corps has issued 57 nationwide 
permits (NWPs), a number of which may be of particular use to 
individual property owners. Authorization to discharge dredged or fill 
material is provided under the following NWPs: NWP 3 authorizes 
discharges associated with maintenance of previously authorized and 
serviceable structures and fill; NWP 18 authorizes minor discharges of 
less than 25 cubic yards that result in the loss of no more than \1/
10\-acre of ``waters of the United States,'' which can include 
activities undertaken by a landowner; NWP 29 authorizes discharges that 
result in the loss of no more than \1/2\-acre of non-tidal ``waters of 
the United States'' to support the construction or expansion of a 
single residence or a residential development; NWP 33 authorizes 
temporary discharges associated with construction activities and access 
to construction sites, including for the construction or expansion of a 
home or residential development if the area is restored to pre-
construction conditions; NWP 57 authorizes discharges associated with 
electric utility and telecommunication line activities that result in 
the loss of no more than \1/2\-acre of ``waters of the United States,'' 
including connecting these services to a home or residential 
development; NWP 58 authorizes discharges associated utility line 
activities for water and other substances that result in the loss of no 
more than \1/2\-acre of ``waters of the United States,'' including 
connecting water and sewer lines to a home or residential development. 
These are general descriptions of the selected NWPs. The requirements 
and conditions that apply to the NWPs are set forth in the rules 
promulgating the NWPs. Corps personnel in the local district office can 
help explain the requirements of each NWP, including any conditions 
that have been added to the NWPs on a regional basis. Corps districts 
may add conditions to activity-specific NWP authorizations to ensure 
that those activities result in no more than minimal individual and 
cumulative adverse environmental effects. Corps districts across the 
country have issued approximately 450 regional general permits, and 
information on these permits is provided on each district's website. 
All general permits, including NWPs, are valid for a maximum of five 
years and are subject to change, so this overview is for illustrative 
purposes only. Property owners should always consult the most recently 
promulgated general permit information.
    Additional information on NWPs is available at the following link: 
https://www.usace.army.mil/Missions/Civil-Works/Regulatory-Program-and-Permits/Nationwide-Permits/.
(4) If I need an individual section 404 permit, how do I obtain 
coverage?
    The vast majority of activities subject to Clean Water Act section 
404 permits are authorized under general permits; however, some 
activities do require authorization under an individual permit 
(generally because of a high level of impact on ``waters of the United 
States'' or because the project proponent cannot comply with all 
applicable conditions of a general permit). While the process of 
applying for and evaluating an individual permit is more involved than 
for a general permit, the time and complexity involved is commensurate 
with the level of impact and can still be efficient. The Corps

[[Page 3135]]

Regulatory Program personnel will work with an applicant to ensure 
potential adverse impacts associated with the proposed action have been 
to the extent practicable avoided or minimized. This effort focuses not 
only on lessening adverse impacts to waters, including wetlands, but 
also other important aspects of the human environment including 
endangered species and historic properties. Focused consideration of 
these and other environmental factors during the project planning stage 
could help avoid more complex and time-consuming evaluations and 
consultations. As a result of this process of avoidance, minimization, 
and with the implementation of certain compensatory mitigation, the 
Corps ends up denying less than 1% of individual permit requests \136\ 
while still ensuring compliance with important Federal laws such as the 
Endangered Species Act and the National Historic Preservation Act. The 
Corps estimates that the typical cost associated with the individual 
permit process for a project affecting up to three acres of 
jurisdictional waters is between $15,500 and $37,300. The typical 
homeowner's project is far more likely to fall within the terms of a 
general permit (e.g., NWP 29, which authorizes discharges that result 
in the loss of no more than \1/2\-acre of non-tidal ``waters of the 
United States'' to support the construction or expansion of a single 
residence or a residential development) than to require filling 
multiple acres of jurisdictional waters.\137\
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    \136\ Based on data from the Corps' ORM2 database.
    \137\ According to recent U.S. Census data, even in the State 
with the largest lot size, California, the average lot size is 
substantially smaller than three acres, see https://www.census.gov/construction/chars/, meaning the acreage of jurisdictional waters 
would be smaller still.
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D. Placement of the Definition of ``Waters of the United States'' in 
the Code of Federal Regulations

1. This Rule
    Prior to the 2020 NWPR, the definition of ``waters of the United 
States'' was historically placed in eleven locations in the Code of 
Federal Regulations (CFR). For the sake of simplicity, in this rule, as 
in the 2020 NWPR, the agencies are codifying the definition of ``waters 
of the United States'' in only two places in the CFR--in Title 33, 
which generally implements the Corps' statutory authority, at 33 CFR 
328.3, and in Title 40, which generally implements EPA's statutory 
authority, at 40 CFR 120.2. Additionally, the agencies' final rule 
makes several ministerial changes to EPA's regulations at part 120: (1) 
this rule deletes the definition of ``navigable waters'' at 40 CFR 
120.2 and adds the definition to the section ``purpose and scope'' at 
40 CFR 120.1 and (2) this rule adds clarifying text to the section 
``purpose and scope'' at 40 CFR 120.1.
2. Summary of the Agencies' Consideration of Public Comments and 
Rationale for This Rule
    The agencies proposed to maintain the definition of ``waters of the 
United States'' at 33 CFR part 328 and in one location at 40 CFR 120.2. 
The agencies also proposed to delete the definition of ``navigable 
waters'' at 40 CFR 120.2 and to add the definition to the section 
``purpose and scope'' of part 120 at 40 CFR 120.1. Additionally, the 
agencies proposed to add additional clarifying text to the section 
``purpose and scope'' at 40 CFR 120.1.
    The agencies solicited comment on their deletion of the definition 
of ``navigable waters'' at 40 CFR 120.2 and adding it instead to the 
section ``purpose and scope'' at 40 CFR 120.1. One commenter supported 
the proposed changes to placement of the definition of ``waters of the 
United States.'' As the agencies stated in the preamble to the 2020 
NWPR, the placement of the definition in two locations, at 33 CFR 328.3 
and 40 CFR 120.2, increases convenience for the reader and provides 
clarity to the public that there is a single definition of ``waters of 
the United States'' applicable to the Clean Water Act and its 
implementing regulations. The placement has no substantive implications 
for the scope of Clean Water Act jurisdiction. 85 FR 22328 (April 21, 
2020). In the sections of the CFR where EPA's definition previously 
existed, 40 CFR 110.1, 112.2, 116.3, 117.1, 122.2, 230.3, 232.2, 300.5, 
302.3, 401.11, and Appendix E to 40 CFR part 300, the 2020 NWPR cross-
references the then-newly created section of the regulations containing 
the definition of ``waters of the United States.'' The cross-references 
to 40 CFR 120.2 are maintained by this rule.
    As discussed in the preamble of the proposed rule, the agencies 
intend for the other revisions to 40 CFR 120--deleting the definition 
of ``navigable waters'' at 40 CFR 120.2, adding the definition into the 
section ``purpose and scope'' at 40 CFR 120.1, and adding clarifying 
text to the section ``purpose and scope'' at 40 CFR 120.1--to be 
editorial and clarifying changes and not substantive changes from EPA's 
regulations. The agencies have concluded that these minor revisions add 
consistency between EPA's regulations at 40 CFR 120 and the Corps' 
regulations defining ``waters of the United States'' at 33 CFR 328.3. 
As a result of this non-substantive revision, the agencies' definitions 
will have parallel numerical and alphabetical subsections, providing 
clarity for the public. The changes have no implications for Clean 
Water Act program implementation. They are made for the sole purpose of 
enhancing the clarity of EPA's regulation and providing consistency 
across the implementing agencies' regulations.

E. Severability

    The purpose of this section is to clarify the agencies' intent with 
respect to the severability of provisions of this rule. Each category 
and subcategory of jurisdictional waters in this rule is capable of 
operating independently. If any provision or jurisdictional category or 
subcategory of this rule is determined by judicial review or operation 
of law to be invalid, that partial invalidation will not render the 
remainder of this rule invalid. Likewise, if the application of any 
portion of this rule to a particular circumstance is determined to be 
invalid, the agencies intend that the rule remain applicable to all 
other circumstances.
    For example, in the absence of jurisdiction over a subcategory of 
jurisdictional tributaries, adjacent wetlands, or paragraph (a)(5) 
waters, references to those subcategories of waters could be removed, 
and the agencies would continue to exercise jurisdiction under the 
remainder of this rule (including unaffected subcategories). Each 
exclusion in paragraph (b) and each definitional provision of paragraph 
(c) also operates independently of the other provisions in this rule 
and is intended to be severable. Moreover, as noted, the agencies 
intend applications of this rule to be severable from other 
applications, such that if the application of this rule to a given 
circumstance is held invalid, the rule remains enforceable in all other 
applications. For example, if a court were to determine that a wetland 
cannot be treated as adjacent if it is separated from a jurisdictional 
water by road or other barrier, the agencies intend that other 
categories of wetlands within the rule's definition of ``adjacent'' 
would remain subject to jurisdiction.

F. Jurisdictional Determinations Issued Under Previous Rules

    The agencies recognize that promulgation of this rule could lead to 
questions regarding AJDs issued under prior rules defining ``waters of 
the United States'' and the utility of such AJDs to support actions, 
such as

[[Page 3136]]

requests for permits, following the effective date of this rule. In 
this section, the agencies seek to provide clarity on the effect of 
this rule on previously issued AJDs and the extent to which AJDs issued 
under prior rules may be relied upon. To be clear, this discussion 
merely explains pre-existing legal principles and does not create new 
requirements.
    An AJD is a Corps document stating the presence or absence of 
``waters of the United States'' on a parcel or a written statement and 
map identifying the limits of ``waters of the United States'' on a 
parcel. See 33 CFR 331.2. As a matter of policy, AJDs are valid for a 
period of five years from the date of issuance, unless new information 
warrants revision of the determination before the expiration date, or a 
District Engineer identifies specific geographic areas with rapidly 
changing environmental conditions that merit reverification on a more 
frequent basis. See U.S. Army Corps of Engineers, RGL No. 05-02, 
section 1(a), p. 1 (June 2005). Additionally, the possessor of a valid 
AJD may ask the Corps to reassess a parcel and issue a new AJD before 
the five-year expiration date.\138\
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    \138\ In contrast to AJDs, preliminary jurisdictional 
determinations (PJDs) are advisory in nature and have no expiration 
date. See 33 CFR 331.2; see also U.S. Army Corps of Engineers, RGL 
No. 16-01 (October 2005) (RGL 16-01). This rule has no impact on 
existing PJDs.
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    This rule does not invalidate AJDs issued under prior definitions 
of ``waters of the United States.'' As such, any existing AJD--except 
AJDs issued under the vacated 2020 NWPR, which are discussed below--
will remain valid to support regulatory actions, such as permitting, 
until its expiration date, unless one of the criteria for revision is 
met under RGL 05-02 or the recipient of such an AJD asks the Corps to 
issue a new AJD. Because agency actions are governed by the rule in 
effect at the time an AJD is issued and not when the request was made, 
all approved jurisdictional determinations issued on or after the 
effective date of this rule will be made consistent with this rule.
    Because two district courts vacated the 2020 NWPR, the agencies 
have received many questions regarding the validity of AJDs issued 
under the 2020 NWPR (hereinafter, ``NWPR AJDs''). In response to such 
inquiries, the agencies have explained through previous public 
statements that NWPR AJDs, unlike AJDs issued under other rules that 
were changed pursuant to notice-and-comment rulemaking rather than 
vacatur, may not reliably state the presence, absence, or limits of 
``waters of the United States'' on a parcel and will not be relied upon 
by the Corps in making new permit decisions following the Arizona 
district court's August 30, 2021 order vacating the 2020 NWPR.\139\ 
Therefore, for any currently pending or future permit action that 
intends to rely on a NWPR AJD, the Corps will discuss with the 
applicant, as detailed in RGL 16-01,\140\ whether the applicant would 
like to receive a new AJD completed under the regulatory regime in 
effect at that time (i.e., the pre-2015 regulatory regime until this 
rule is effective or this rule after it becomes effective) to continue 
their permit processing or whether the applicant would like to proceed 
in reliance on a preliminary jurisdictional determination or ``no JD 
whatsoever.'' \141\
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    \139\ U.S. Army Corps of Engineers, Navigable Waters Protection 
Rule Vacatur (published January 5, 2022), available at https://www.usace.army.mil/Media/Announcements/Article/2888988/5-january-2022-navigable-waters-protection-rule-vacatur/; U.S. Environmental 
Protection Agency, Current Implementation of Waters of the United 
States (published January 5, 2022), available at https://www.epa.gov/wotus/current-implementation-waters-united-states.
    \140\ U.S. Army Corps of Engineers, RGL No. 16-01 (October 
2016).
    \141\ See RGL 16-01 (explaining the ``no JD whatsoever'' 
option).
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    NWPR AJDs issued prior to the Arizona district court's vacatur 
decision and that are not associated with a permit action (also known 
as ``stand-alone'' AJDs under RGL 16-01) will remain valid stand-alone 
AJDs until their expiration date unless one of the criteria for 
revision is met under RGL 05-02 or if the recipient of such an AJD 
requests that a new AJD be provided. A recipient of a stand-alone NWPR 
AJD should nonetheless be aware of the reliability considerations noted 
above. Moreover, a recipient of a stand-alone NWPR AJD that intends to 
discharge into waters identified as non-jurisdictional under the 
vacated 2020 NWPR but that may be jurisdictional under the pre-2015 
regulatory regime or this rule may want to discuss their options with 
the Corps due to the unreliability of those jurisdictional findings.

G. Implementation Tools

    This rule provides implementation guidance informed by sound 
science, implementation tools, and other resources, drawing on more 
than a decade of post-Rapanos implementation experience. Section IV.C 
of this preamble addressing specific categories of waters provides 
guidance on implementation of each provision of this rule. This section 
addresses advancements in the implementation data, tools, and methods 
that are relevant to jurisdictional determinations under this rule. 
Although the agencies may also rely on site-specific information from 
landowners or field visits, the agencies generally use publicly 
available data, tools, and methods to inform determinations of 
jurisdiction. These same resources can also be used by the public and 
practitioners to assess aquatic resources to better understand whether 
a particular resource may be jurisdictional. Some of these resources 
are freely available, and others may charge a fee for use. Note that 
members of the public are not required to conduct or provide any of the 
analyses described in this section as part of a JD request. JD 
requesters need only provide the agencies with a minimal amount of 
information, including identification of the boundaries of the area of 
interest, to request a JD. See RGL 16-01, Appendix 1. The following 
discussion is provided to clarify how available data, tools, and 
methods inform the agencies' determinations and confirm that interested 
parties may use these same resources to inform their own siting 
decisions, if so desired.
    Since the Rapanos decision, there have been dramatic advancements 
in the data, tools, and methods used to make jurisdictional 
determinations, including in the digital availability of information 
and data. In 2006, when the agencies began to implement the Rapanos and 
Carabell decisions, there were fewer implementation tools and support 
resources to guide staff in jurisdictional decision-making under the 
relatively permanent and significant nexus standards. Agency staff were 
forced to rely heavily on information provided in applicant submittals 
and available aerial imagery to make jurisdictional decisions or to 
schedule an in-person site visit to review the property themselves. The 
2007 Corps Instructional Guidebook encouraged practitioners to utilize 
maps, aerial photography, soil surveys, watershed studies, scientific 
literature, previous jurisdictional determinations for the review area, 
and local development plans to complete accurate jurisdictional 
decisions or analysis. For more complicated situations or decisions 
involving significant nexus evaluations, the Guidebook encouraged 
practitioners to identify and evaluate the functions relevant to the 
significant nexus by incorporating literature citations and/or 
references from studies pertinent to the parameters being reviewed. For 
significant nexus decisions specifically, the Guidebook instructed 
practitioners to consider all

[[Page 3137]]

available hydrologic information (e.g., gage data, precipitation 
records, flood predictions, historic records of water flow, statistical 
data, personal observations/records, etc.) and physical indicators of 
flow including the presence and characteristics of a reliable OHWM.
    The Corps also issued RGL No. 07-01 \142\ in 2007. RGL No. 07-01 
laid out principal considerations for evaluating the significant nexus 
of a tributary and its adjacent wetlands which included the volume, 
duration, and frequency of flow of water in the tributary, proximity of 
the tributary to a traditional navigable water, and functions performed 
by the tributary and its adjacent wetlands. This RGL highlighted 
wetland delineation data sheets, delineation maps, and aerial 
photographs as important for adequate information to support all 
jurisdictional decision-making. Gathering the data necessary to support 
preliminary or approved jurisdictional decisions was often time 
consuming for staff and the regulated public. There were not many 
nationally available repositories for much of the information that the 
agency staff utilized in decision-making, particularly during the first 
years of implementing the guidance. Despite these challenges, the 
agencies and others in the practitioner community gained substantial 
collective experience implementing the relatively permanent and 
significant nexus standards from 2006 to 2015.
---------------------------------------------------------------------------

    \142\ RGL No. 07-01 was later superseded by RGL 08-02, which was 
superseded by RGL 16-01, neither of which addressed significant 
nexus evaluations.
---------------------------------------------------------------------------

    Since 2015, there have been dramatic improvements to the quantity 
and quality of water resource information available on the internet, 
including information and tools that are freely available to the 
public. The agencies and other practitioners can use online mapping 
tools to determine whether waters are connected or sufficiently close 
to ``waters of the United States,'' and new user interfaces have been 
developed that make it easier and quicker to access information from a 
wide variety of sources. Furthermore, some information used to only be 
available in hard-copy paper files, including water resource 
inventories and habitat assessments, and many of these resources have 
been made available online or updated with new information.
    The following overview of several tools and data that have been 
developed or improved since 2015 is intended to demonstrate how case-
specific evaluations can be made more quickly and consistently than 
ever before. Advancements in geographic information systems (GIS) 
technology and cloud-hosting services have led to an evolution in user 
interfaces for publicly available datasets frequently used in 
jurisdictional decision-making such as the NWI, USGS NHD, soil surveys, 
aerial imagery, and other geospatial analysis tools like USGS 
StreamStats. Not only are the individual datasets more easily 
accessible to users, but it has also become much easier for users to 
quickly integrate these various datasets using desktop or online tools 
like map viewers to consolidate and evaluate the relevant data in one 
visual platform. Such map viewers can assist, for example, with 
considering the factors and assessing the functions in paragraph 
(c)(6). The EPA Watershed Assessment, Tracking, and Environmental 
Results System (WATERS) GeoViewer is an example of a web mapping 
application that provides accessibility to many spatial dataset layers 
like NHDPlus and watershed reports for analysis and interpretation. 
Another web mapping application is the EPA's EnviroAtlas, which 
provides information and interpretative tools to help facilitate 
surface water assessments using multiple data layers such as land 
cover, stream hydrography, soils, and topography. Several States also 
have State-specific interactive online mapping tools called Water 
Resource Registries (WRRs). WRRs host publicly available GIS data 
layers providing various information such as the presence of wetlands, 
land use/cover, impaired waters, and waters of special concern. Other 
websites like the Corps' Jurisdictional Determinations and Permits 
Decision site and webservices like EPA's Enforcement and Compliance 
History Online (ECHO) Map Services allow users to find geospatial and 
technical information about Clean Water Act section 404 and NPDES 
permitted discharges. Information on approved jurisdictional 
determinations finalized by the Corps is also available on the Corps' 
Jurisdictional Determinations and Permit Decisions site and EPA's Clean 
Water Act Approved Jurisdictional Determinations website.
    The data that are available online have increased in quality as 
well as quantity. The NHD has undergone extensive improvements in data 
availability, reliability, and resolution since 2015, including the 
release of NHDPlus High Resolution datasets for the conterminous U.S. 
and Hawaii, with Alaska under development. One notable improvement in 
NHD data quality is that the flow-direction network data are much more 
accurate than in the past. Improvements have also been made to the NWI 
website and geospatial database, which has served as the primary source 
of wetland information in the United States for many years. In 2016, 
NWI developed a more comprehensive dataset (NWI Version 2) that is 
inclusive of all surface water features in addition to wetlands. This 
NWI Version 2 dataset provides more complete geospatial data on surface 
waters and wetlands than has been available in the past and provides a 
more efficient means to make determinations of flow and water movement 
in surface water basins and channels, as well as in wetlands. The 
agencies and other practitioners can use this dataset to help assess 
potential hydrologic connectivity between waterways and wetlands. For 
example, it can be used in part to help the agencies identify wetlands 
that do not meet the definition of adjacent (waters assessed under 
paragraph (a)(5)).
    The availability of aerial and satellite imagery has improved 
dramatically since 2015. This imagery is used to observe the presence 
or absence of flow and identify relatively permanent flow in tributary 
streams and hydrologic connections to waters. The agencies often use a 
series of aerial and satellite images, spanning multiple years and 
taken under normal climatic conditions, to determine the flow 
characteristics of a tributary, as a first step to determine if 
additional field-based information is needed to determine the flow 
characteristics. Other practitioners may also use aerial and satellite 
images to identify aquatic resources and inform assessments of those 
aquatic resources. The growth of the satellite imagery industry has 
reduced the need to perform as many field investigations to verify 
Clean Water Act jurisdiction.\143\ Some of these services charge a fee 
for use, but others are freely available.
---------------------------------------------------------------------------

    \143\ For example, satellite imagery services are available 
through services such as DigitalGlobe, available at https://discover.maxar.com/, and aerial photography and imagery are 
available through services such as USGS EarthExplorer, available at 
https://earthexplorer.usgs.gov/, and National Aeronautics and Space 
Administration (NASA) Earth Data, available at https://earthdata.nasa.gov/ gov/. The USGS Landsat Level-3 Dynamic Surface Water 
Extent (DSWE) product, available at https://www.usgs.gov/landsat-missions/landsat-dynamic-surface-water-extent-science-products?qt-science_support_page_related_con=0#qt-science_support_page_related_con, is a specific example of a tool 
that may be useful for identifying surface water inundation on the 
landscape in certain geographic areas.
---------------------------------------------------------------------------

    Similarly, the availability of LIDAR data has increased in 
availability and utility for informing decisions on Clean

[[Page 3138]]

Water Act jurisdiction. LIDAR produces high-resolution elevation data 
(<1-3 meter) which can be used to create maps of local topography. The 
high-resolution maps can highlight the potential hydrologic connections 
and flowpaths at a site. Where LIDAR data have been processed to create 
a bare earth model, detailed depictions of the land surface reveal 
subtle elevation changes and characteristics of the land surface, 
including the identification of tributaries. Hydrologists, for example, 
have long used digital elevation models of the earth's surface to model 
watershed dynamics, and the agencies have used such information where 
available to help inform jurisdictional decisions. LIDAR-derived 
digital elevation models tend to be high resolution (<1-3 meter), so 
they are particularly helpful for identifying fine-scale surface 
features. For example, LIDAR-indicated tributaries can be correlated 
with aerial photography or other tools to help identify channels and to 
help determine flow permanence (e.g., relatively permanent flow) in the 
absence of a field visit. The agencies have been using such remote 
sensing and desktop tools to assist with identifying jurisdictional 
tributaries for many years, and such tools are particularly critical 
where data from the field are unavailable, or a field visit is not 
possible. High-resolution LIDAR data are becoming more widespread for 
engineering and land use planning purposes. The USGS is in the process 
of collecting LIDAR data for the entire United States.\144\ LIDAR data 
are available for download via the National Map Download Client 
(available at https://apps.nationalmap.gov/downloader/#/) and LIDAR-
derived digital elevation models are available via the 3DEP 
LidarExplorer (available at https://apps.nationalmap.gov/lidar-explorer/#/). However, LIDAR-derived elevation maps are not always 
available, so the agencies use other elevation data, including digital 
elevation models derived from other sources (e.g., 10-meter digital 
elevation models) and topographic maps to help determine the elevation 
on a site and to assess the potential location of tributaries.
---------------------------------------------------------------------------

    \144\ See U.S. Geological Survey. ``What is Lidar data and where 
can I download it? '' Available at https://www.usgs.gov/faqs/what-lidar-data-and-where-can-i-download-it.
---------------------------------------------------------------------------

    Since 2015, tools have been developed that automate some of the 
standard practices the agencies rely on to assist in jurisdictional 
determinations. One example of this automation is the Antecedent 
Precipitation Tool (APT), which was released to the public in 2020 and 
had been used internally by the agencies prior to its public release. 
The APT is a desktop tool developed by the Corps and is commonly used 
by the agencies to help determine whether field data collection and 
other site-specific observations occurred under normal climatic 
conditions. In addition to providing a standardized methodology to 
evaluate normal precipitation conditions (``precipitation normalcy''), 
the APT can also be used to assess the presence of drought conditions, 
as well as the approximate dates of the wet and dry seasons for a given 
location. As discussed in section IV.B.3 of this preamble, above, 
precipitation data are often not useful in providing evidence as to 
whether a surface water connection exists in a typical year, as 
required by the 2020 NWPR. However, the agencies have long used the 
methods employed in the APT to provide evidence that wetland 
delineations are made under normal circumstances or to account for 
abnormalities during interpretation of data. The development and public 
release of the APT has accelerated the speed at which these analyses 
are completed; has standardized methods, which reduces errors; and has 
enabled more people to perform these analyses themselves, including 
members of the public. Automated tools like the APT will continue to be 
important for supporting jurisdictional decision-making. The agencies 
will consider opportunities to develop and improve tools that should be 
helpful for further automating and streamlining the JD process in the 
future.
    Site visits are still sometimes needed to perform on-site 
observations of surface hydrology or collect regionally-specific field-
based indicators of relatively permanent flow (e.g., the presence of 
riparian vegetation or certain aquatic macroinvertebrates). The methods 
and instruments used to collect field data have also improved since 
2015, such as the development of rapid, field-based SDAMs that use 
physical and biological indicators to determine the flow duration class 
of a stream reach. The agencies have previously used existing SDAMs 
developed by Federal and State agencies to identify perennial, 
intermittent, or ephemeral streams. The agencies will continue to use 
these tools whenever they are determined to be a reliable source of 
information for the specific water feature of interest. The agencies 
are currently working to develop region-specific SDAMs for nationwide 
coverage, which will promote consistent implementation across the 
United States in a manner that accounts for differences between each 
ecoregion. The region-specific SDAMs will be publicly available, with 
user manuals that will guide not only the agencies, but also other 
practitioners, in applying the methods to assess aquatic resources. 
Additional information on the agencies' efforts to develop SDAMs is 
available on the Regional Streamflow Duration Assessment Methods web 
page, available at https://www.epa.gov/streamflow-duration-assessment. 
Consistent with longstanding practice, the agencies will make decisions 
based on the best available information.
    EPA and the Army have also been working with other Federal agencies 
on improving aquatic resource mapping and modeling, including working 
with the Department of Interior (DOI). EPA, USGS, and FWS have a long 
history of working together to map the nation's aquatic resources. The 
agencies will continue to collaborate with DOI to enhance the NHD, NWI, 
and other products to better map the nation's water resources while 
enhancing the utility and availability of such geospatial products for 
implementation of Clean Water Act programs.

H. Publicly Available Jurisdictional Information and Permit Data

    The agencies have provided information on jurisdictional 
determinations that is readily available to the public. The Corps 
maintains a website, available at https://permits.ops.usace.army.mil/orm-public, that presents information on the Corps' approved 
jurisdictional determinations and Clean Water Act section 404 permit 
decisions. The website allows users to search and view basic 
information on approved jurisdictional determinations and permit 
decisions (including latitude and longitude) and to filter the 
determinations using different parameters like Corps District and year. 
The website also contains a link to an associated approved 
jurisdictional determination form. Similarly, EPA maintains a website, 
available at https://watersgeo.epa.gov/cwa/CWA-JDs/, that presents 
information on approved jurisdictional determinations made by the Corps 
under the Clean Water Act since August 28, 2015. EPA's website also 
allows users to search, sort, map, view, filter, and download 
information on approved jurisdictional determinations using different 
search parameters (e.g., by year, location, State, watershed, 
regulatory regime). The website includes a map viewer that shows where 
waters have been determined to be jurisdictional or non-

[[Page 3139]]

jurisdictional based on the approved jurisdictional determinations 
available on the site.\145\ These websites will incorporate information 
on approved jurisdictional determinations made under the revised 
definition of ``waters of the United States.'' EPA also maintains on 
its website information on certain dischargers permitted under Clean 
Water Act section 402, including the Permit Compliance System and 
Integrated Compliance Information System database, available at https://www.epa.gov/enviro/pcs-icis-overview, as well as the EnviroMapper, 
available at https://enviro.epa.gov/enviro/em4ef.home, and How's My 
Waterway, available at https://www.epa.gov/waterdata/hows-my-waterway. 
The agencies also intend to provide links to the public to any 
guidance, forms, or memoranda of agreement relevant to the definition 
of ``waters of the United States'' on EPA's website at https://www.epa.gov/wotus.
---------------------------------------------------------------------------

    \145\ With respect to the waters determined to be non-
jurisdictional, section IV.C.7 of this preamble describes the 
regulatory exclusions in this rule, which reflect the agencies' 
longstanding practice and technical judgment that certain waters and 
features are not subject to the Clean Water Act. Additionally, based 
on the agencies' experience, many waters assessed under this rule 
will not have a significant nexus to paragraph (a)(1) waters, and 
thus will not be jurisdictional under the Clean Water Act under this 
rule. See section IV.C.9.b of this preamble for examples of waters 
that would not likely have a significant nexus under this rule.
---------------------------------------------------------------------------

V. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review; Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted 
to the Office of Management and Budget (OMB) for review. Any changes 
made in response to OMB recommendations have been documented in the 
docket for this action. The agencies prepared an economic analysis of 
the potential costs and benefits associated with this action. This 
analysis, the Economic Analysis for the Final ``Revised Definition of 
`Waters of the United States''' Rule, is available in the docket for 
this action.
    This rule establishing the definition of ``waters of the United 
States'' does not by itself impose costs or benefits. Potential costs 
and benefits would only be incurred as a result of actions taken under 
existing Clean Water Act programs relying on the definition of ``waters 
of the United States'' (i.e., sections 303, 311, 401, 402, and 404) 
that are not otherwise modified by this rule. Entities currently are, 
and will continue to be, regulated under these programs that protect 
``waters of the United States'' from pollution and destruction. Each of 
these programs may subsequently impose costs as a result of 
implementation of their specific regulations.
    The agencies prepared the economic analysis pursuant to the 
requirements of Executive Orders 12866 and 13563 to provide information 
to the public. The economic analysis was done for informational 
purposes and the final decisions on the scope of ``waters of the United 
States'' in the rulemaking are not based on consideration of the 
potential benefits and costs in the economic analysis. Within the 
Economic Analysis for the Final Rule, the agencies have analyzed the 
potential benefits and costs associated with various Clean Water Act 
programs that could result from this rule relative to two baselines. 
The primary baseline analyzes costs and benefits associated with moving 
from the pre-2015 regulatory regime that is currently being implemented 
to the definition in this rule. This rule imposes de minimis costs and 
generates de minimis benefits under the primary baseline.
    Though two courts have vacated the 2020 NWPR and the pre-2015 
regulatory regime is currently being implemented, the agencies have 
chosen to provide additional information to the public with the 2020 
NWPR as a secondary baseline in the Economic Analysis for the Final 
Rule. This rule will replace the 2020 NWPR in the Code of Federal 
Regulations as the definition of ``waters of the United States'' in the 
agencies' regulations. The agencies project that compared to the 2020 
NWPR, this rule would define more waters as within the scope of the 
Clean Water Act. The analysis of estimated costs and benefits of this 
rule is contained in the Economic Analysis for the Final Rule and is 
available in the docket for this action.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA because it does not contain any information collection 
activities. However, this action may change terms and concepts used by 
EPA and Army to implement certain programs. The agencies thus may need 
to revise some of their collections of information to be consistent 
with this action and will do so consistent with the PRA process.

C. Regulatory Flexibility Act (RFA)

    The agencies certify that this rule will not have a significant 
economic impact on a substantial number of small entities under the RFA 
for several reasons. First, as demonstrated in Chapter I of the 
Economic Analysis for the Final Rule, this rule would codify a 
regulatory regime with de minimis differences from the one currently 
being implemented nationwide due to the vacatur of the 2020 NWPR.
    This rule will also not have a significant economic impact on a 
substantial number of small entities under the RFA because under the 
RFA, the impact of concern is any significant adverse economic impact 
on small entities, because the primary purpose of the initial 
regulatory flexibility analysis is to identify and address regulatory 
alternatives ``which minimize any significant economic impact of the 
proposed rule on small entities.'' 5 U.S.C. 603(a). This rule does not 
directly apply to specific entities and therefore it does not 
``subject'' any entities of any size to any specific regulatory burden. 
Rather, it is designed to clarify the statutory term ``navigable 
waters,'' defined as ``waters of the United States,'' which defines the 
scope of Clean Water Act jurisdiction. 33 U.S.C. 1362(7). The scope of 
Clean Water Act jurisdiction is informed by the text, structure, and 
history of the Clean Water Act and relevant Supreme Court case law, as 
well as the best available science and the agencies' experience and 
technical expertise. None of these factors are readily informed by an 
RFA analysis. See, e.g., Cement Kiln Recycling Coal. v. EPA, 255 F.3d 
856, 869 (D.C. Cir. 2001) (``[T]o require an agency to assess the 
impact on all of the nation's small businesses possibly affected by a 
rule would be to convert every rulemaking process into a massive 
exercise in economic modeling, an approach we have already 
rejected.''); Michigan v. EPA, 213 F.3d 663, 688-89 (D.C. Cir. 2000) 
(holding that the RFA imposes ``no obligation to conduct a small entity 
impact analysis of effects'' on entities which it regulates only 
``indirectly''); Am. Trucking Ass'n v. EPA, 175 F.3d 1027, 1045 (D.C. 
Cir. 1999) (``[A]n agency may justify its certification under the RFA 
upon the ``factual basis'' that the rule does not directly regulate any 
small entities.''); Mid-Tex Elec. Co-op, Inc. v. FERC, 773 F.2d 327, 
343 (D.C. Cir. 1985) (``Congress did not intend to require that every 
agency consider every indirect effect that any regulation might have on 
small businesses in any stratum of the national economy.'').

[[Page 3140]]

    Finally, the agencies conclude that this rule will not 
significantly impact small entities because it narrows the scope of 
jurisdiction from the text of the 1986 regulations. Because fewer 
waters will be subject to the Clean Water Act under this rule than fall 
within the scope of the text of the regulations in effect, this action 
will not affect small entities to a greater degree than the existing 
regulations currently in effect. A key change is the deletion of the 
provision in the 1986 regulations that defines ``waters of the United 
States'' as all paragraph (a)(3) ``other waters'' such as intrastate 
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 
could affect interstate or foreign commerce including any such waters: 
which are or could be used by interstate or foreign travelers for 
recreational or other purposes; from which fish or shellfish are or 
could be taken and sold in interstate or foreign commerce; or which are 
used or could be used for industrial purposes by industries in 
interstate commerce. Under this rule, a broad interstate commerce 
connection is not sufficient to meet the definition of ``waters of the 
United States.'' Instead, waters must meet either the relatively 
permanent standard or the significant nexus standard. Further, the 
final rule eliminates jurisdiction over tributaries and adjacent 
wetlands based on their connection to paragraph (a)(5) waters. In 
addition, this rule would explicitly exclude some features and waters 
over which the agencies have not generally asserted jurisdiction, but 
which are not excluded in the text of the 1986 regulations, and in so 
doing eliminates the authority of the agencies to determine in case-
specific circumstances that some such waters are jurisdictional 
``waters of the United States.'' This rule also provides new 
limitations on the scope of jurisdictional tributaries and most 
adjacent wetlands by establishing a requirement that they meet either 
the relatively permanent standard or the significant nexus standard. 
Together, these changes serve to narrow the scope of this rule in 
comparison to the text of the regulation in effect. Because the rule 
narrows the scope of jurisdiction from the text of the 1986 
regulations, this action will not have a significant adverse economic 
impact on a substantial number of small entities, and therefore no 
regulatory flexibility analysis is required.
    Nevertheless, the agencies recognize that the scope of the term 
``waters of the United States'' is of great national interest, 
including within the small business community. Given this interest, the 
agencies sought early input from representatives of small entities 
while formulating a proposed definition of this term, including holding 
a public meeting dedicated to hearing feedback from small entities on 
August 25, 2021 (see Environmental Protection Agency, 2021 ``Waters of 
the United States'' Public Meeting Materials, available at https://www.epa.gov/wotus/2021-waters-united-states-public-meeting-materials). 
The agencies also met with small entities during the public comment 
period to hear their thoughts on the proposed rule. The Office of 
Advocacy of the U.S. Small Business Administration hosted EPA and Army 
staff in January 2022 to discuss the proposed rule with small entities 
at its Small Business Environmental Roundtables. The agencies met with 
small agricultural interests and their representatives for a roundtable 
on January 7, 2022, and met with other small entities on January 10, 
2022. The agencies have addressed this feedback in the preamble 
relating to these topics and in the discussion above.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The final definition of ``waters of the United 
States'' applies broadly to Clean Water Act programs. The action 
imposes no enforceable duty on any Tribal, State, or local governments, 
or the private sector.

E. Executive Order 13132: Federalism

    Consulting with State and local government officials, or their 
representative national organizations, is an important step in the 
process prior to proposing regulations that may have federalism 
implications under the terms of Executive Order 13132. The agencies 
engaged State and local governments over a 60-day federalism 
consultation period during development of this rule, beginning with the 
initial federalism consultation meeting on August 5, 2021, and 
concluding on October 4, 2021. Twenty intergovernmental organizations, 
including eight of the ten organizations identified in EPA's 2008 
Executive Order 13132 Guidance, attended the initial Federalism 
consultation meeting, as well as 12 associations representing State and 
local governments. Organizations in attendance included the following: 
National Governors Association, National Conference of State 
Legislatures, United States Conference of Mayors, National League of 
Cities, National Association of Counties, National Association of Towns 
and Townships, County Executives of America, Environmental Council of 
the States, Association of State Wetland Managers, Association of State 
Drinking Water Administrators, National Association of State 
Departments of Agriculture, Western States Water Council, National 
Association of Clean Water Agencies, National Rural Water Association, 
National Association of Attorneys General, National Water Resources 
Association, National Municipal Stormwater Alliance, Western Governors' 
Association, American Water Works Association, and Association of 
Metropolitan Water Agencies. In addition, the agencies received letters 
from State and local governments, as well as government associations, 
as part of this initial federalism consultation process. A total of 37 
letters were submitted from twelve State government agencies, five 
local government agencies, seventeen intergovernmental associations, 
and three State-level associations of local governments. All letters 
received by the agencies during this consultation may be found in the 
docket (Docket ID No. EPA-HQ-OW-2021-0602) for this rule.
    A Summary Report of Federalism Consultation for the proposed rule 
was published in December 2021. The agencies continued to engage with 
State and local governments during the public comment period. The 
agencies hosted two roundtable sessions for State and local officials 
on January 24 and January 27, 2022. These State and local government 
roundtables provided an overview of the proposed rule and discussions 
of a variety of topics including significant nexus, specific waters, 
exclusions, and State regulatory programs. Each roundtable meeting 
included breakout groups for officials by region so they could discuss 
and provide feedback to the agencies. Organizations in attendance 
included a wide variety of State and local government agencies, as well 
as intergovernmental associations and State-level associations of local 
governments. These meetings and the letters provided represent a wide 
and diverse range of interests, positions, comments, and 
recommendations to the agencies. Common themes from the feedback 
included the importance of promoting State-Federal partnerships; the 
need for the agencies to take a regional approach to determinations of 
jurisdiction; and support for further

[[Page 3141]]

clarity and consistency with significant nexus and relatively permanent 
determinations. The agencies have prepared a report summarizing their 
consultation and additional outreach to State and local governments and 
the results of this outreach. A copy of the final report is available 
in the docket (Docket ID. No. EPA-HQ-OW-2021-0602) for this rule.
    Under the technical requirements of Executive Order 13132, agencies 
must conduct a federalism consultation as outlined in the Executive 
Order for regulations that (1) have federalism implications, that 
impose substantial direct compliance costs on State and local 
governments, and that are not required by statute; or (2) that have 
federalism implications and that preempt State law. The agencies 
conducted a 60-day federalism consultation due to strong interest on 
the part of State and local governments on this issue over the years 
and potential effects associated with a change in the definition of 
``waters of the United States.'' However, the agencies have concluded 
that compared to the status quo, this rule does not impose any new 
costs or other requirements on States, preempt State law, or limit 
States' policy discretion; rather, it defines the scope of ``waters of 
the United States'' to which Clean Water Act programs apply. Executive 
Order paras. (6)(b) and (6)(c). This final rule draws a boundary 
between waters subject to Clean Water Act protections and those that 
Tribes and States may manage under their independent authorities. As 
compared to the status quo, this action will not have substantial 
direct effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Documentation 
for this decision is contained in the Economic Analysis for the Final 
Rule, which can be found in the docket for this action.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action may have Tribal implications. However, it will neither 
impose substantial direct compliance costs on federally recognized 
Tribal governments, nor preempt Tribal law.
    EPA and the Army consulted with Tribal officials under the EPA 
Policy on Consultation and Coordination with Indian Tribes and the 
Department of the Army American Indian and Alaska Native Policy early 
in the process of developing this regulation to permit them to have 
meaningful and timely input into its development.
    The agencies initiated a Tribal consultation and coordination 
process before proposing this rule by sending a ``Notification of 
Consultation and Coordination'' letter on July 30, 2021, to all 574 
Tribes federally recognized at that time. The letter invited Tribal 
leaders and designated consultation representatives to participate in 
the Tribal consultation and coordination process. The agencies engaged 
Tribes over a 66-day Tribal consultation period during development of 
the proposed rule. The consultation included two webinars on August 19 
and August 24, 2021, in which the agencies answered questions directly 
from Tribal representatives and heard their initial feedback on the 
agencies' rulemaking effort. The agencies responded to all requests for 
one-on-one consultation and met with four Tribes at a staff-level and 
with four Tribes at a leader-to-leader level. All letters received by 
the agencies as part of Tribal consultation may be found in the docket 
(Docket ID No. EPA-HQ-OW-2021-0602) for this rule.
    The agencies also continued to engage with Tribes post-proposal, 
including via regional Tribal meetings and through a virtual Tribal 
roundtable on January 20, 2022. The topics addressed during this 
roundtable included options for describing and implementing the 
relatively permanent and significant nexus standards, the definitions 
of specific waters such as interstate waters and paragraph (a)(5) 
waters, and the implementation of exclusions. The most common themes 
from the feedback were: the importance of streams and wetlands to 
Tribal cultural resources; the need for the agencies to consider 
regional differences; the need for the agencies to respect the Federal 
trust responsibility and Tribal treaty rights; and the importance of 
restoring a broad definition of ``waters of the United States.'' Some 
Tribes commented on the importance of protecting ephemeral streams, 
which were eliminated from jurisdiction under the 2020 NWPR, as well as 
protecting wetlands that were excluded under the 2020 NWPR. Several 
Tribes spoke about the need to include ``waters of the tribe'' in the 
definition of ``waters of the United States.'' Additionally, several 
Tribes stated support for furthering environmental justice with the 
proposed rulemaking. Some Tribes also expressed support for accounting 
for climate change in some manner in the definition of ``waters of the 
United States.'' The agencies have prepared a report summarizing the 
consultation and further engagement with Tribal Nations. This report 
(Docket ID. No. EPA-HQ-OW-2021-0602) is available in the docket for 
this rule.
    As required by Executive Order 13175 section 7(a), the EPA's Tribal 
Consultation Official has certified that the requirements have been met 
in a meaningful and timely manner. A copy of the certification is 
included in the docket for this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    EPA and the Army interpret Executive Order 13045 as applying only 
to those regulatory actions that concern environmental health or safety 
risks that the agencies have reason to believe may disproportionately 
affect children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because the environmental health or safety risks 
addressed by this action do not present a disproportionate risk to 
children.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

I. National Technology Transfer and Advancement Act

    This rule does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
Federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on minority populations (Indigenous peoples and/or people of 
color) and low-income populations.
    EPA and the Army believe that this action does not have 
disproportionately high and adverse human health or environmental 
effects on Indigenous peoples, people of color, and/or low-income 
populations. The documentation for this decision is contained in the 
Economic Analysis for

[[Page 3142]]

the Final Rule, which can be found in the docket for this action.
    The agencies recognize that the burdens of environmental pollution 
and climate change often fall disproportionately on communities with 
environmental justice concerns (e.g., Indigenous peoples, people of 
color, and low-income populations), and have qualitatively assessed 
impacts to these groups in the Economic Analysis for the Final Rule. 
Climate change will exacerbate the existing risks faced by communities 
with environmental justice concerns.
    For this rule, consistent with Executive Order 12898 and Executive 
Order 14008 on ``Tackling the Climate Crisis at Home and Abroad'' (86 
FR 7619; January 27, 2021), the agencies examined whether the change in 
benefits due to this rule may be differentially distributed among 
communities with environmental justice concerns in the affected areas 
when compared to both baselines. Regardless of baseline, for most of 
the wetlands and affected waters impacted by this rule at a hydrologic 
unit code (HUC) 12 watershed level,\146\ there was no evidence of 
potential environmental justice impacts warranting further analysis. It 
is expected that where there were environmental justice impacts at the 
HUC 12 scale as compared to the secondary baseline of the 2020 NWPR, 
those impacts would be beneficial to communities with environmental 
justice concerns because this rule will result in more waters being 
jurisdictional than would be under the 2020 NWPR. For example, 
communities with environmental justice concerns in the arid West may 
have experienced increased water pollution and associated health 
impacts under the 2020 NWPR due to that rule's lack of Federal 
protection for ephemeral streams and their adjacent wetlands.
---------------------------------------------------------------------------

    \146\ HUC boundaries are established by USGS and NRCS. These 
boundaries are numbered using nested codes to represent the scale of 
the watershed size. For example, HUC 12 watersheds are smaller than 
HUC 4 watersheds.
---------------------------------------------------------------------------

K. Congressional Review Act

    This action is subject to the Congressional Review Act, and the 
agencies will submit a rule report to each House of the Congress and to 
the Comptroller General of the United States. This action is not a 
``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects

33 CFR Part 328

    Administrative practice and procedure, Environmental protection, 
Navigation (water), Water pollution control, Waterways.

40 CFR Part 120

    Environmental protection, Water pollution control, Waterways.

Michael L. Connor,
Assistant Secretary of the Army (Civil Works), Department of the Army.
Michael S. Regan,
Administrator, Environmental Protection Agency.

Title 33--Navigation and Navigable Waters

    For the reasons set out in the preamble, 33 CFR part 328 is amended 
as follows:

PART 328--DEFINITION OF WATERS OF THE UNITED STATES

0
1. The authority citation for part 328 continues to read as follows:

    Authority:  33 U.S.C. 1251 et seq.


0
2. Revise Sec.  328.3 to read as follows:


Sec.  328.3  Definitions.

    For the purpose of this regulation these terms are defined as 
follows:
    (a) Waters of the United States means:
    (1) Waters which are:
    (i) Currently used, or 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;
    (ii) The territorial seas; or
    (iii) Interstate waters, including interstate wetlands;
    (2) Impoundments of waters otherwise defined as waters of the 
United States under this definition, other than impoundments of waters 
identified under paragraph (a)(5) of this section;
    (3) Tributaries of waters identified in paragraph (a)(1) or (2) of 
this section:
    (i) That are relatively permanent, standing or continuously flowing 
bodies of water; or
    (ii) That either alone or in combination with similarly situated 
waters in the region, significantly affect the chemical, physical, or 
biological integrity of waters identified in paragraph (a)(1) of this 
section;
    (4) Wetlands adjacent to the following waters:
    (i) Waters identified in paragraph (a)(1) of this section; or
    (ii) Relatively permanent, standing or continuously flowing bodies 
of water identified in paragraph (a)(2) or (a)(3)(i) of this section 
and with a continuous surface connection to those waters; or
    (iii) Waters identified in paragraph (a)(2) or (3) of this section 
when the wetlands either alone or in combination with similarly 
situated waters in the region, significantly affect the chemical, 
physical, or biological integrity of waters identified in paragraph 
(a)(1) of this section;
    (5) Intrastate lakes and ponds, streams, or wetlands not identified 
in paragraphs (a)(1) through (4) of this section:
    (i) That are relatively permanent, standing or continuously flowing 
bodies of water with a continuous surface connection to the waters 
identified in paragraph (a)(1) or (a)(3)(i) of this section; or
    (ii) That either alone or in combination with similarly situated 
waters in the region, significantly affect the chemical, physical, or 
biological integrity of waters identified in paragraph (a)(1) of this 
section.
    (b) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (a)(2) through (5) of 
this section:
    (1) Waste treatment systems, including treatment ponds or lagoons, 
designed to meet the requirements of the Clean Water Act;
    (2) Prior converted cropland designated by the Secretary of 
Agriculture. The exclusion would cease upon a change of use, which 
means that the area is no longer available for the production of 
agricultural commodities. 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;
    (3) Ditches (including roadside ditches) excavated wholly in and 
draining only dry land and that do not carry a relatively permanent 
flow of water;
    (4) Artificially irrigated areas that would revert to dry land if 
the irrigation ceased;
    (5) Artificial lakes or ponds created by excavating or diking dry 
land to collect and retain water and which are used exclusively for 
such purposes as stock watering, irrigation, settling basins, or rice 
growing;
    (6) Artificial reflecting or swimming pools or other small 
ornamental bodies of water created by excavating or diking dry land to 
retain water for primarily aesthetic reasons;
    (7) Waterfilled depressions created in dry land incidental to 
construction activity and pits excavated in dry land for the purpose of 
obtaining fill, sand, or gravel unless and until the construction or 
excavation operation is abandoned and the resulting body of

[[Page 3143]]

water meets the definition of waters of the United States; and
    (8) Swales and erosional features (e.g., gullies, small washes) 
characterized by low volume, infrequent, or short duration flow.
    (c) In this section, the following definitions apply:
    (1) Wetlands means those areas that are inundated or saturated by 
surface or ground water at a frequency and duration sufficient to 
support, and that under normal circumstances do support, a prevalence 
of vegetation typically adapted for life in saturated soil conditions. 
Wetlands generally include swamps, marshes, bogs, and similar areas.
    (2) Adjacent means bordering, contiguous, or neighboring. Wetlands 
separated from other waters of the United States by man-made dikes or 
barriers, natural river berms, beach dunes, and the like are ``adjacent 
wetlands.''
    (3) High tide line means the line of intersection of the land with 
the water's surface at the maximum height reached by a rising tide. The 
high tide line may be determined, in the absence of actual data, by a 
line of oil or scum along shore objects, a more or less continuous 
deposit of fine shell or debris on the foreshore or berm, other 
physical markings or characteristics, vegetation lines, tidal gages, or 
other suitable means that delineate the general height reached by a 
rising tide. The line encompasses spring high tides and other high 
tides that occur with periodic frequency but does not include storm 
surges in which there is a departure from the normal or predicted reach 
of the tide due to the piling up of water against a coast by strong 
winds such as those accompanying a hurricane or other intense storm.
    (4) Ordinary high water mark means that line on the shore 
established by the fluctuations of water and indicated by physical 
characteristics such as clear, natural line impressed on the bank, 
shelving, changes in the character of soil, destruction of terrestrial 
vegetation, the presence of litter and debris, or other appropriate 
means that consider the characteristics of the surrounding areas.
    (5) Tidal waters means those waters that rise and fall in a 
predictable and measurable rhythm or cycle due to the gravitational 
pulls of the moon and sun. Tidal waters end where the rise and fall of 
the water surface can no longer be practically measured in a 
predictable rhythm due to masking by hydrologic, wind, or other 
effects.
    (6) Significantly affect means a material influence on the 
chemical, physical, or biological integrity of waters identified in 
paragraph (a)(1) of this section. To determine whether waters, either 
alone or in combination with similarly situated waters in the region, 
have a material influence on the chemical, physical, or biological 
integrity of waters identified in paragraph (a)(1) of this section, the 
functions identified in paragraph (c)(6)(i) of this section will be 
assessed and the factors identified in paragraph (c)(6)(ii) of this 
section will be considered:
    (i) Functions to be assessed:
    (A) Contribution of flow;
    (B) Trapping, transformation, filtering, and transport of materials 
(including nutrients, sediment, and other pollutants);
    (C) Retention and attenuation of floodwaters and runoff;
    (D) Modulation of temperature in waters identified in paragraph 
(a)(1) of this section; or
    (E) Provision of habitat and food resources for aquatic species 
located in waters identified in paragraph (a)(1) of this section;
    (ii) Factors to be considered:
    (A) The distance from a water identified in paragraph (a)(1) of 
this section;
    (B) Hydrologic factors, such as the frequency, duration, magnitude, 
timing, and rate of hydrologic connections, including shallow 
subsurface flow;
    (C) The size, density, or number of waters that have been 
determined to be similarly situated;
    (D) Landscape position and geomorphology; and
    (E) Climatological variables such as temperature, rainfall, and 
snowpack.

Title 40--Protection of Environment

    For reasons set out in the preamble, 40 CFR part 120 is amended as 
follows:

PART 120--DEFINITION OF WATERS OF THE UNITED STATES

0
3. The authority citation for part 120 continues to read as follows:

    Authority:  33 U.S.C. 1251 et seq.


0
4. Revise Sec.  120.1 to read as follows:


Sec.  120.1  Purpose and scope.

    This part contains the definition of ``waters of the United 
States'' for purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. 
and its implementing regulations. EPA regulations implementing the 
Clean Water Act use the term ``navigable waters,'' which is defined at 
section 502(7) of the Clean Water Act as ``the waters of the United 
States, including the territorial seas,'' or the term ``waters of the 
United States.'' In light of the statutory definition, the definition 
in this section establishes the scope of the terms ``waters of the 
United States'' and ``navigable waters'' in EPA's regulations.

0
5. Revise Sec.  120.2 to read as follows:


Sec.  120.2  Definitions.

    For the purpose of this regulation these terms are defined as 
follows:
    (a) Waters of the United States means:
    (1) Waters which are:
    (i) Currently used, or 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;
    (ii) The territorial seas; or
    (iii) Interstate waters, including interstate wetlands;
    (2) Impoundments of waters otherwise defined as waters of the 
United States under this definition, other than impoundments of waters 
identified under paragraph (a)(5) of this section;
    (3) Tributaries of waters identified in paragraph (a)(1) or (2) of 
this section:
    (i) That are relatively permanent, standing or continuously flowing 
bodies of water; or
    (ii) That either alone or in combination with similarly situated 
waters in the region, significantly affect the chemical, physical, or 
biological integrity of waters identified in paragraph (a)(1) of this 
section;
    (4) Wetlands adjacent to the following waters:
    (i) Waters identified in paragraph (a)(1) of this section; or
    (ii) Relatively permanent, standing or continuously flowing bodies 
of water identified in paragraph (a)(2) or (a)(3)(i) of this section 
and with a continuous surface connection to those waters; or
    (iii) Waters identified in paragraph (a)(2) or (3) of this section 
when the wetlands either alone or in combination with similarly 
situated waters in the region, significantly affect the chemical, 
physical, or biological integrity of waters identified in paragraph 
(a)(1) of this section;
    (5) Intrastate lakes and ponds, streams, or wetlands not identified 
in paragraphs (a)(1) through (4) of this section:
    (i) That are relatively permanent, standing or continuously flowing 
bodies of water with a continuous surface connection to the waters 
identified in paragraph (a)(1) or (a)(3)(i) of this section; or
    (ii) That either alone or in combination with similarly situated 
waters in the region, significantly affect the chemical, physical, or 
biological integrity of waters identified in paragraph (a)(1) of this 
section.

[[Page 3144]]

    (b) The following are not ``waters of the United States'' even 
where they otherwise meet the terms of paragraphs (a)(2) through (5) of 
this section:
    (1) Waste treatment systems, including treatment ponds or lagoons, 
designed to meet the requirements of the Clean Water Act;
    (2) Prior converted cropland designated by the Secretary of 
Agriculture. The exclusion would cease upon a change of use, which 
means that the area is no longer available for the production of 
agricultural commodities. 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;
    (3) Ditches (including roadside ditches) excavated wholly in and 
draining only dry land and that do not carry a relatively permanent 
flow of water;
    (4) Artificially irrigated areas that would revert to dry land if 
the irrigation ceased;
    (5) Artificial lakes or ponds created by excavating or diking dry 
land to collect and retain water and which are used exclusively for 
such purposes as stock watering, irrigation, settling basins, or rice 
growing;
    (6) Artificial reflecting or swimming pools or other small 
ornamental bodies of water created by excavating or diking dry land to 
retain water for primarily aesthetic reasons;
    (7) Waterfilled depressions created in dry land incidental to 
construction activity and pits excavated in dry land for the purpose of 
obtaining fill, sand, or gravel unless and until the construction or 
excavation operation is abandoned and the resulting body of water meets 
the definition of waters of the United States; and
    (8) Swales and erosional features (e.g., gullies, small washes) 
characterized by low volume, infrequent, or short duration flow.
    (c) In this section, the following definitions apply:
    (1) Wetlands means those areas that are inundated or saturated by 
surface or ground water at a frequency and duration sufficient to 
support, and that under normal circumstances do support, a prevalence 
of vegetation typically adapted for life in saturated soil conditions. 
Wetlands generally include swamps, marshes, bogs, and similar areas.
    (2) Adjacent means bordering, contiguous, or neighboring. Wetlands 
separated from other waters of the United States by man-made dikes or 
barriers, natural river berms, beach dunes, and the like are ``adjacent 
wetlands.''
    (3) High tide line means the line of intersection of the land with 
the water's surface at the maximum height reached by a rising tide. The 
high tide line may be determined, in the absence of actual data, by a 
line of oil or scum along shore objects, a more or less continuous 
deposit of fine shell or debris on the foreshore or berm, other 
physical markings or characteristics, vegetation lines, tidal gages, or 
other suitable means that delineate the general height reached by a 
rising tide. The line encompasses spring high tides and other high 
tides that occur with periodic frequency but does not include storm 
surges in which there is a departure from the normal or predicted reach 
of the tide due to the piling up of water against a coast by strong 
winds such as those accompanying a hurricane or other intense storm.
    (4) Ordinary high water mark means that line on the shore 
established by the fluctuations of water and indicated by physical 
characteristics such as clear, natural line impressed on the bank, 
shelving, changes in the character of soil, destruction of terrestrial 
vegetation, the presence of litter and debris, or other appropriate 
means that consider the characteristics of the surrounding areas.
    (5) Tidal waters means those waters that rise and fall in a 
predictable and measurable rhythm or cycle due to the gravitational 
pulls of the moon and sun. Tidal waters end where the rise and fall of 
the water surface can no longer be practically measured in a 
predictable rhythm due to masking by hydrologic, wind, or other 
effects.
    (6) Significantly affect means a material influence on the 
chemical, physical, or biological integrity of waters identified in 
paragraph (a)(1) of this section. To determine whether waters, either 
alone or in combination with similarly situated waters in the region, 
have a material influence on the chemical, physical, or biological 
integrity of waters identified in paragraph (a)(1) of this section, the 
functions identified in paragraph (c)(6)(i) of this section will be 
assessed and the factors identified in paragraph (c)(6)(ii) of this 
section will be considered:
    (i) Functions to be assessed:
    (A) Contribution of flow;
    (B) Trapping, transformation, filtering, and transport of materials 
(including nutrients, sediment, and other pollutants);
    (C) Retention and attenuation of floodwaters and runoff;
    (D) Modulation of temperature in waters identified in paragraph 
(a)(1) of this section; or
    (E) Provision of habitat and food resources for aquatic species 
located in waters identified in paragraph (a)(1) of this section;
    (ii) Factors to be considered:
    (A) The distance from a water identified in paragraph (a)(1) of 
this section;
    (B) Hydrologic factors, such as the frequency, duration, magnitude, 
timing, and rate of hydrologic connections, including shallow 
subsurface flow;
    (C) The size, density, or number of waters that have been 
determined to be similarly situated;
    (D) Landscape position and geomorphology; and
    (E) Climatological variables such as temperature, rainfall, and 
snowpack.

[FR Doc. 2022-28595 Filed 1-17-23; 8:45 am]
BILLING CODE 6560-50-P