The Navigable Waters Protection Rule: Definition of “Waters of the United States”

 
CONTENT
Federal Register, Volume 85 Issue 77 (Tuesday, April 21, 2020)
[Federal Register Volume 85, Number 77 (Tuesday, April 21, 2020)]
[Rules and Regulations]
[Pages 22250-22342]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-02500]
[[Page 22249]]
Vol. 85
Tuesday,
No. 77
April 21, 2020
Part II
Department of Defense
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Department of the Army, Corps of Engineers
Environmental Protection Agency
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33 CFR Part 328
40 CFR Parts 110, 112, 116, et al.
The Navigable Waters Protection Rule: Definition of ``Waters of the
United States''; Final Rule
Federal Register / Vol. 85, No. 77 / Tuesday, April 21, 2020 / 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 Parts 110, 112, 116, 117, 120, 122, 230, 232, 300, 302, and
401
[EPA-HQ-OW-2018-0149; FRL-10004-88-OW]
RIN 2040-AF75
The Navigable Waters Protection Rule: 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 and the Department of the
Army are publishing a final rule defining the scope of waters federally
regulated under the Clean Water Act. The Navigable Waters Protection
Rule is the second step in a comprehensive, two-step process intended
to review and revise the definition of ``waters of the United States''
consistent with the Executive Order signed on February 28, 2017,
``Restoring the Rule of Law, Federalism, and Economic Growth by
Reviewing the `Waters of the United States' Rule.'' Once effective, it
replaces the rule published on October 22, 2019. This final rule
implements the overall objective of the Clean Water Act to restore and
maintain the integrity of the nation's waters by maintaining federal
authority over those waters that Congress determined should be
regulated by the Federal government under its Commerce Clause powers,
while adhering to Congress' policy directive to preserve States'
primary authority over land and water resources. This final definition
increases the predictability and consistency of Clean Water Act
programs by clarifying the scope of ``waters of the United States''
federally regulated under the Act.
DATES: This rule is effective on June 22, 2020.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OW-2018-0149. All documents in the docket are
listed on the http://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: Michael McDavit, Oceans, Wetlands, and
Communities Division, Office of Water (4504-T), Environmental
Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460;
telephone number: (202) 566-2465; email address: [email protected]; or
Jennifer A. Moyer, Regulatory Community of Practice (CECW-CO-R), U.S.
Army Corps of Engineers, 441 G Street NW, Washington, DC 20314;
telephone number: (202) 761-5903; email address:
[email protected].
SUPPLEMENTARY INFORMATION:
Table of Contents
I. General Information
 A. Where can I find information related to this rulemaking?
 B. What action are the agencies taking?
 C. What is the agencies' authority for taking this action?
II. Background
 A. The Final Rule
 B. History of This Rulemaking
 1. The Clean Water Act
 2. Regulatory History
 3. U.S. Supreme Court Decisions
 4. The 2015 Rule
 C. Executive Order 13778 and the ``Step One'' Rulemaking
 D. Summary of Stakeholder Outreach and the ``Step Two''
Rulemaking
 E. Overview of Legal Construct for the Final Rule
 1. Statutory Framework
 2. U.S. Supreme Court Precedent
 3. Principles and Considerations
 F. Summary of Final Rule as Compared to the 1986 Regulations
Recodified in the 2019 Rule and the 2015 Rule
 G. Existing Guidance
III. Definition of ``Waters of the United States''
 A. Key Terms and Concepts
 1. Typical Year
 2. Perennial, Intermittent, and Ephemeral
 3. Breaks
 B. Territorial Seas and Traditional Navigable Waters
 C. Interstate Waters
 D. Tributaries
 E. Ditches
 F. Lakes and Ponds, and Impoundments of Jurisdictional Waters
 G. Adjacent Wetlands
 H. Waters and Features That Are Not Waters of the United States
 I. Placement of the Definition of ``Waters of the United
States'' in the Code of Federal Regulations
IV. State, Tribal, and Federal Agency Datasets of Waters of the
United States
V. Overview of the Effects of the Rule and Supporting Analyses
VI. Statutory and Executive Order Reviews
 A. Executive Order 12866: Regulatory Planning and Review;
Executive Order 13563: Improving Regulation and Regulatory Review
 B. Executive Order 13771: Reducing Regulation and Controlling
Regulatory Costs
 C. Paperwork Reduction Act
 D. Regulatory Flexibility Act
 E. Unfunded Mandates Reform Act
 F. Executive Order 13132: Federalism
 G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
 H. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
 I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
 J. National Technology Transfer and Advancement Act
 K. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
 L. Congressional Review Act
I. General Information
A. Where can I find information related to this rulemaking?
 1. Docket. An official public docket for this action has been
established under Docket ID No. EPA-HQ-OW-2018-0149. The official
public docket consists of the documents specifically referenced in this
action and other information related to this action. The official
public docket is the collection of materials that is available for
public viewing at the OW Docket, EPA West, Room 3334, 1301 Constitution
Ave. NW, Washington, DC 20004. This Docket Facility is open from 8:30
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The
OW Docket telephone number is (202) 566-2426. A reasonable fee will be
charged for copies.
 2. Electronic Access. You may access this Federal Register document
electronically under the ``Federal Register'' listings at http://www.regulations.gov. An electronic version of the public docket is
available through EPA's electronic public docket and comment system,
EPA Dockets. You may access EPA Dockets at http://www.regulations.gov
to view public comments as they are submitted and posted, access the
index listing of the contents of the official public docket, and access
those documents in the public docket that are available electronically,
including the economic and regulatory analyses for the final rule. For
additional information about
[[Page 22251]]
EPA's public docket, visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm. Although not all docket materials may
be available electronically, you may still access any of the publicly
available docket materials through the Docket Facility.
B. What action are the agencies taking?
 In this notice, the agencies are publishing a final rule defining
``waters of the United States'' in 33 CFR 328.3 and 40 CFR 120.2.
C. 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.
II. Background
A. The Final Rule
 The U.S. Environmental Protection Agency (EPA) and the U.S.
Department of the Army (Army or Corps) (together, ``the agencies'') are
publishing the Navigable Waters Protection Rule defining the scope of
waters subject to federal regulation under the Clean Water Act (CWA or
the Act), in light of the U.S. Supreme Court cases in United States v.
Riverside Bayview Homes (Riverside Bayview), Solid Waste Agency of
Northern Cook County v. United States (SWANCC), and Rapanos v. United
States (Rapanos), and consistent with Executive Order 13778, signed on
February 28, 2017, entitled ``Restoring the Rule of Law, Federalism,
and Economic Growth by Reviewing the `Waters of the United States'
Rule.''
 In this final rule, the agencies interpret the term ``waters of the
United States'' to encompass: The territorial seas and traditional
navigable waters; perennial and intermittent tributaries that
contribute surface water flow to such waters; certain lakes, ponds, and
impoundments of jurisdictional waters; and wetlands adjacent to other
jurisdictional waters. Paragraph (a) of the final rule identifies four
categories of waters that are ``waters of the United States.'' These
waters are referred to as ``jurisdictional'' in this notice and in the
regulatory text. Paragraph (b) of the final rule identifies those
waters and features that are excluded from the definition of ``waters
of the United States.'' These waters are referred to as ``non-
jurisdictional'' or ``excluded'' in this notice and as ``non-
jurisdictional'' in the regulatory text. Paragraph (c) of the final
rule defines applicable terms.
 As a baseline concept, this final rule recognizes that waters of
the United States are waters within the ordinary meaning of the term,
such as oceans, rivers, streams, lakes, ponds, and wetlands, and that
not all waters are waters of the United States. The final rule includes
the agencies' longstanding category of the territorial seas and
traditional navigable waters. A ``tributary'' is defined in the final
rule as a river, stream, or similar naturally occurring surface water
channel that contributes surface water flow to a territorial sea 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 must be perennial or
intermittent in a typical year. The alteration or relocation of a
tributary does not modify its jurisdictional status as long as it
continues to be perennial or intermittent and contributes surface water
flow to a traditional navigable water or territorial sea in a typical
year. A tributary does not lose its jurisdictional status if it
contributes surface water flow to a downstream jurisdictional water in
a typical year through a channelized non-jurisdictional surface water
feature, through a subterranean river, through a culvert, dam, tunnel,
or other similar artificial feature, or through a debris pile, boulder
field, or similar natural feature. The term ``tributary'' includes 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 territorial sea in a typical year.
 The final rule defines ``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. The agencies note that to be jurisdictional, an ``impoundment
of a jurisdictional water'' must be an impoundment of a territorial sea
or traditional navigable water, tributary, jurisdictional lake or pond,
or an adjacent wetland, and must meet the conditions in paragraph
(c)(6) of the final rule. A lake, pond, or impoundment of a
jurisdictional water does not lose its jurisdictional status if it
contributes surface water flow to a downstream jurisdictional water in
a typical year through a channelized non-jurisdictional surface water
feature, through a culvert, dike, spillway, or similar artificial
feature, or through a debris pile, boulder field, or similar natural
feature. A lake, pond, or impoundment of a jurisdictional water is also
jurisdictional if, in a typical year, it is inundated by flooding from
a territorial sea or traditional navigable water, or tributary, or from
another jurisdictional lake, pond, or impoundment.
 The final rule defines ``adjacent wetlands'' as wetlands that abut
a territorial sea or traditional navigable water, a tributary, or a
lake, pond, or impoundment of a jurisdictional water; are inundated by
flooding from a territorial sea or traditional navigable water, a
tributary, or a lake, pond, or impoundment of a jurisdictional water in
a typical year; are physically separated from a territorial sea or
traditional navigable water, a tributary, or a lake, pond, or
impoundment of a jurisdictional water only by a natural berm, bank,
dune, or similar natural feature; or are physically separated from a
territorial sea or traditional navigable water, a tributary, or a lake,
pond, or impoundment of a jurisdictional water only by an artificial
dike, barrier, or similar artificial structure so long as that
structure allows for a direct hydrological surface connection to the
territorial sea or traditional navigable water, tributary, or lake,
pond, or impoundment of a jurisdictional water in a typical year, such
as through a culvert, flood or tide gate, pump, or similar artificial
feature. ``Abut'' means when a wetland touches a territorial sea,
traditional navigable water, tributary, or lake, pond, or impoundment
of a jurisdictional water at least at one point or side. An adjacent
wetland is jurisdictional in its entirety when a road or similar
artificial structure divides the wetland, as long as the structure
allows for a direct hydrologic surface connection through or over that
structure in a typical year.
 The final rule excludes from the definition of ``waters of the
United States'' all waters or features not mentioned above. In addition
to this general exclusion, the final rule specifically clarifies that
waters of the United States do not include the following:
 Groundwater, including groundwater drained through
subsurface drainage systems;
 ephemeral features that flow only in direct response to
precipitation, including ephemeral streams, swales, gullies, rills, and
pools;
 diffuse stormwater runoff and directional sheet flow over
upland;
 ditches that are not traditional navigable waters,
tributaries, or that are
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not constructed in adjacent wetlands, subject to certain limitations;
 prior converted cropland;
 artificially irrigated areas that would revert to upland
if artificial irrigation ceases;
 artificial lakes and ponds that are not jurisdictional
impoundments and that are constructed or excavated in upland or non-
jurisdictional waters;
 water-filled depressions constructed or excavated in
upland or in non-jurisdictional waters incidental to mining or
construction activity, and 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 run-off;
 groundwater recharge, water reuse, and wastewater
recycling structures constructed or excavated in upland or in non-
jurisdictional waters; and
 waste treatment systems.
 In addition, the agencies have defined the terms ``upland,''
``prior converted cropland,'' and ``waste treatment system'' to improve
regulatory predictability and clarity.
 To develop this revised definition of ``waters of the United
States,'' the agencies looked to the text and structure of the CWA, as
informed by its legislative history and Supreme Court guidance, and
took into account the agencies' expertise, policy choices, and
scientific principles. This final rule presents a unifying legal theory
for federal jurisdiction over those waters and wetlands that maintain a
sufficient surface water connection to traditional navigable waters or
the territorial seas. This definition strikes a reasonable and
appropriate balance between Federal and State waters and carries out
Congress' overall objective to restore and maintain the integrity of
the nation's waters in a manner that preserves the traditional
sovereignty of States over their own land and water resources. The
final rule also provides clarity and predictability for Federal
agencies, States, Tribes, the regulated community, and the public. This
final rule is intended to ensure that the agencies operate within the
scope of the Federal government's authority over navigable waters under
the CWA and the Commerce Clause of the U.S. Constitution.
B. History of This Rulemaking
1. The Clean Water Act
 Congress amended the Federal Water Pollution Control Act (FWPCA),
or the CWA as it is commonly called,\1\ in 1972 to address longstanding
concerns regarding the quality of the nation's waters and the federal
government's ability to address those concerns under existing law.
Prior to 1972, the ability to control and redress water pollution in
the nation's waters largely fell to the Corps under the Rivers and
Harbors Act of 1899 (RHA). While much of that statute focused on
restricting obstructions to navigation on the nation's major waterways,
section 13 of the RHA 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.'' \2\ 33 U.S.C. 407. Congress had also enacted the
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 (giving the statute its
current formal name), 1961, and 1965. The early versions of the CWA
promoted 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.
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 \1\ The FWPCA is commonly referred to as the CWA following the
1977 amendments to the FWPCA. Public Law 95-217, 91 Stat. 1566
(1977). For ease of reference, the agencies will generally refer to
the FWPCA in this notice as the CWA or the Act.
 \2\ The term ``navigable water of the United States'' is a term
of art used to refer to waters subject to federal jurisdiction under
the RHA. See, e.g., 33 CFR 329.1. The term is not synonymous with
the phrase ``waters of the United States'' under the CWA, see id.,
and the general term ``navigable waters'' has different meanings
depending on the context of the statute in which it is used. See,
e.g., PPL Montana, LLC v. Montana, 565 U.S. 576, 591-93 (2012).
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 These early statutory efforts, however, 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), so Congress performed
a ``total restructuring'' and ``complete rewriting'' of the existing
statutory framework in 1972, id. at 317 (quoting legislative history of
1972 amendments). That restructuring resulted in the enactment of a
comprehensive scheme (including voluntary as well as regulatory
programs) designed to prevent, reduce, and eliminate pollution in the
nation's waters generally, and to regulate the discharge of pollutants
into navigable waters specifically. See, e.g., S.D. Warren Co. v. Maine
Bd. of Envtl. Prot., 547 U.S. 370, 385 (2006) (noting that ``the Act
does not stop at controlling the `addition of pollutants,' but deals
with `pollution' generally'').
 The objective of the new statutory scheme was ``to restore and
maintain the chemical, physical, and biological integrity of the
Nation's waters.'' 33 U.S.C. 1251(a). In order to meet that objective,
Congress declared two national goals: (1) ``that the discharge of
pollutants into the navigable waters be eliminated by 1985''; and (2)
``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 by
July 1, 1983 . . . .'' Id. at 1251(a)(1)-(2).
 Congress also established several key policies that direct the work
of the agencies to effectuate those goals. For example, Congress
declared as a national policy ``that the discharge of toxic pollutants
in toxic amounts be prohibited; . . . that Federal financial assistance
be provided to construct publicly owned waste treatment works; . . .
that areawide waste treatment management planning processes be
developed and implemented to assure adequate control of sources of
pollutants in each State; . . . [and] that programs for the control of
nonpoint sources of pollution be developed and implemented in an
expeditious manner so as to enable the goals of this Act to be met
through the control of both point and nonpoint sources of pollution.''
33 U.S.C. 1251(a)(3)-(7).
 Congress provided a major role for the States in implementing the
CWA, balancing the preservation of the traditional power of States to
regulate land and water resources within their borders with the need
for a national water quality regulation. For example, the statute
highlighted ``the policy of the 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
. . . of land and water resources.'' 33 U.S.C. 1251(b). Congress also
declared as a national policy that States manage the major construction
grant program and implement the core permitting programs authorized by
the statute, among other responsibilities. Id. Congress added that
``[e]xcept as expressly provided in this Act, nothing in this Act shall
. . . be construed as impairing or in any manner affecting any right or
jurisdiction of the States with respect to the waters (including
boundary waters) of such States.'' Id. at 1370.\3\ Congress
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pledged the Federal government to provide technical support and
financial aid to the States ``in connection with the prevention,
reduction, and elimination of pollution.'' Id. at 1251(b).
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 \3\ 33 U.S.C. 1370 also prohibits authorized States from
adopting any limitations, prohibitions, or standards that are less
stringent than required by the CWA.
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 To carry out these policies, Congress broadly defined ``pollution''
to mean ``the man-made or man-induced alteration of the chemical,
physical, biological, and radiological integrity of water,'' 33 U.S.C.
1362(19), in keeping with the objective of the Act ``to restore and
maintain the chemical, physical, and biological integrity of the
Nation's waters.'' Id. at 1251(a). Congress then crafted a non-
regulatory statutory framework to provide technical and financial
assistance to the States to prevent, reduce, and eliminate pollution in
the nation's waters generally. For example, section 105 of the Act,
``Grants for research and development,'' authorized the EPA ``to make
grants to any State, municipality, or intermunicipal or interstate
agency for the purpose of assisting in the development of any project
which will demonstrate a new or improved method of preventing,
reducing, and eliminating the discharge into any waters of pollutants
from sewers which carry storm water or both storm water and
pollutants.'' Id. at 1255(a)(1) (emphasis added). Section 105 also
authorized the EPA ``to make grants to any State or States or
interstate agency to demonstrate, in river basins or portions thereof,
advanced treatment and environmental enhancement techniques to control
pollution from all sources . . . including nonpoint sources, . . .
[and] . . . to carry out the purposes of section 301 of this Act . . .
for research and demonstration projects for prevention of pollution of
any waters by industry including, but not limited to, the prevention,
reduction, and elimination of the discharge of pollutants.'' Id. at
1255(b)-(c) (emphasis added); see also id. at 1256(a) (authorizing the
EPA to issue ``grants to States and to interstate agencies to assist
them in administering programs for the prevention, reduction, and
elimination of pollution'').
 Section 108, ``Pollution control in the Great Lakes,'' authorized
the EPA to enter into agreements with any State to develop plans for
the ``elimination or control of pollution, within all or any part of
the watersheds of the Great Lakes.'' 33 U.S.C. 1258(a) (emphasis
added); see also id. at 1268(a)(3)(C) (defining the ``Great Lakes
System'' as ``all the streams, rivers, lakes, and other bodies of water
within the drainage basin of the Great Lakes'') (emphasis added).
Similar broad pollution control programs were created for other major
watersheds, including, for example, 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). Some commenters noted that the Great
Lakes, Long Island Sound, Chesapeake Bay, and Lake Champlain are waters
of the United States to which regulatory programs apply, and that the
purpose of the technical assistance and grants in the cited sections is
to assist states and others in achieving the requirements of the Act.
The agencies agree that these waters are waters of the United States,
but the emphasized language in the cited provisions above makes clear
that these provisions address all bodies of water in the watersheds of
the Great Lakes, Long Island Sound, Chesapeake Bay, and Lake Champlain,
regardless of the jurisdictional status of those waters.
 In addition to the Act's non-regulatory measures to control
pollution of the nation's waters generally, Congress created a federal
regulatory permitting program designed to address the discharge of
pollutants into a subset of those waters identified as ``navigable
waters,'' defined as ``the waters of the United States,'' 33 U.S.C.
1362(7). Section 301 contains the key regulatory mechanism: ``Except as
in compliance with this section and sections 302, 306, 307, 318, 402,
and 404 of this Act, the discharge of any pollutant by any person shall
be unlawful.'' Id. at 1311(a). A ``discharge of a pollutant'' is
defined to include ``any addition of any pollutant to navigable waters
from any point source,'' defined to mean ``any discernible, confined
and discrete conveyance'' such as a pipe or ditch. Id. at 1362(12),
(14). The term ``pollutant'' means ``dredged spoil, solid waste,
incinerator residue, sewage, garbage, sewage sludge, munitions,
chemical wastes, biological materials, radioactive materials, heat,
wrecked or discarded equipment, rock, sand, cellar dirt and industrial,
municipal, and agricultural waste discharged into water.'' Id. at
1362(6). Thus, it is unlawful to discharge pollutants into the ``waters
of the United States'' from a point source unless the discharge is in
compliance with certain enumerated sections of the CWA, including
obtaining authorization pursuant to the section 402 National Pollutant
Discharge Elimination System (NPDES) permit program or the section 404
dredged or fill material permit program. See id. at 1342, 1344.
Congress therefore intended to achieve the Act's objective ``to restore
and maintain the chemical, physical, and biological integrity of the
Nation's waters'' by addressing pollution of all waters via non-
regulatory means and federally regulating the discharge of pollutants
to the subset of waters identified as ``navigable waters.'' \4\
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 \4\ Members of Congress were aware when they drafted the 1972
CWA amendments that different types of the Nation's waters would be
subject to different degrees of federal control. For instance, in
House debate regarding a proposed and ultimately failed amendment to
prohibit the discharge of pollutants to groundwater in addition to
navigable waters, Representative Don H. Clausen stated, ``Mr.
Chairman, in the early deliberations within the committee which
resulted in the introduction of H.R. 11896, a provision for ground
waters . . . was thoroughly reviewed and it was determined by the
committee that there was not sufficient information on ground waters
to justify the types of controls that are required for navigable
waters . . . . I refer the gentleman to the objectives of this act
as stated in section 101(a). The objective of this act is to restore
and maintain the chemical, physical, and biological integrity of the
Nation's waters. I call your attention to the fact that this does
not say the Nation's [`]navigable waters,' `interstate waters,' or
`intrastate waters.' It just says `waters.' This includes ground
waters.'' 118 Cong. Rec. at 10,667 (daily ed. March 28, 1972).
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 Many commenters on this rulemaking agreed with this summary of the
CWA, stating that it accurately characterizes the full scope of the Act
and the thoughtful, holistic approach Congress enacted to address water
pollution in this country. Many commenters stated that Congress
developed both regulatory and non-regulatory approaches for addressing
water pollution, whereby ``navigable waters'' are subject to federal
regulatory requirements under the CWA but many other classes of the
``nation's waters'' are not. Some commenters disagreed that the CWA
distinguishes between the ``nation's waters'' and a subset of those
waters known as the ``navigable waters.'' Many of these commenters
suggested that the agencies' interpretation is not supported by the
text or structure of the Act and is based instead on
mischaracterizations of the Act's provisions. Some commenters argued
that the two terms are synonymous under the Act, and others stated that
the non-regulatory provisions of the CWA were intended to complement
the regulatory requirements applicable to waters of the United States,
as opposed to addressing a separate category of waters. Fundamental
principles of statutory interpretation support the agencies'
recognition of a distinction between the ``nation's waters'' and
``navigable waters.'' As the Supreme Court has observed, ``[w]e assume
that Congress used two terms because it intended each term to have a
particular, nonsuperfluous meaning.'' Bailey v. United States, 516 U.S.
137, 146 (1995)
[[Page 22254]]
(recognizing the canon of statutory construction against superfluity).
Further, ``the words of a statute must be read in their context and
with a view to their place in the overall statutory scheme.'' FDA v.
Brown & Williamson Tobacco Corp., 529 U.S. 120, 133 (2000) (internal
quotation marks and citation omitted); see also United Sav. Ass'n of
Texas v. Timbers of Inwood Forest Associates, 484 U.S. 365, 371
(``Statutory construction . . . is a holistic endeavor. A provision
that may seem ambiguous in isolation is often clarified by the
remainder of the statutory scheme--because the same terminology is used
elsewhere in a context that makes its meaning clear[.]'') (citation
omitted). Here, the non-regulatory sections of the CWA reveal Congress'
intent to restore and maintain the integrity of the nation's waters
using federal assistance to support State and local partnerships to
control pollution in the nation's waters and a federal regulatory
prohibition on the discharge of pollutants to the navigable waters. If
Congress had intended the terms to be synonymous, it would have used
identical terminology. Instead, Congress chose to use separate terms,
and the agencies are instructed by the Supreme Court to presume
Congress did so intentionally.
 Under the enacted statutory scheme, the States are primarily
responsible for developing water quality standards for waters of the
United States within their borders and reporting on the condition of
those waters to the EPA every two years. 33 U.S.C. 1313, 1315. States
must develop total maximum daily loads (TMDLs) for waters that are not
meeting established water quality standards and must submit those TMDLs
to the EPA for approval. Id. at 1313(d). States also have authority to
issue water quality certifications or waive certification for every
federal permit or license issued within their borders that may result
in a discharge to navigable waters. Id. at 1341.
 These same regulatory authorities can be assumed by Indian tribes
under section 518 of the CWA, which authorizes the EPA to treat
eligible Indian tribes with reservations in a manner similar to States
for a variety of purposes, including administering each of the
principal CWA regulatory programs. 33 U.S.C. 1377(e). In addition,
States and Tribes retain authority to protect and manage the use of
those waters that are not navigable waters under the CWA. See, e.g.,
id. at 1251(b), 1251(g), 1370, 1377(a). At this time, forty-seven
States administer portions of the CWA section 402 permit program for
those waters of the United States within their boundaries,\5\ and two
States (Michigan and New Jersey) administer the section 404 permit
program for those waters that are assumable by States pursuant to
section 404(g). Several additional states are exploring the possibility
of assuming the section 404 permit program. At present, no Tribes
administer the section 402 or 404 programs, although some are exploring
the possibility. For additional information regarding State and tribal
programs, see the Resource and Programmatic Assessment for the final
rule.
---------------------------------------------------------------------------
 \5\ Three States (Massachusetts, New Hampshire, and New Mexico)
do not currently administer any part of the CWA section 402 program.
---------------------------------------------------------------------------
2. Regulatory History
 In May 1973, the EPA issued its first set of regulations to
implement the new NPDES permit program established in the 1972 CWA
amendments. Those regulations defined the phrase ``navigable waters''
as:
 All navigable waters of the United States;
 Tributaries of navigable waters of the United States;
 Interstate waters;
 Intrastate lakes, rivers, and streams which are utilized
by interstate travelers for recreational or other purposes;
 Intrastate lakes, rivers, and streams from which fish or
shellfish are taken and sold in interstate commerce; and
 Intrastate lakes, rivers, and streams which are utilized
for industrial purposes by industries in interstate commerce.
38 FR 13528, 13529 (May 22, 1973) (codified at 40 CFR 125.1 (1973)).
 In 1974, the Corps issued its first set of regulations defining
``waters of the United States'' for the purpose of implementing section
404 of the CWA as well as sections 9, 10, 11, 13, and 14 of the RHA.
These regulations reaffirmed the Corps' view that its dredged and fill
jurisdiction under section 404 was the same as its traditional
jurisdiction under the RHA. See 39 FR 12115, 12119 (Apr. 3, 1974)
(codified at 33 CFR 209.120). Specifically, the Corps defined the
``waters of the United States'' as waters that ``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.'' Id.
 Environmental organizations challenged the Corps' 1974 regulation
in the U.S. District Court for the District of Columbia, arguing that
the Corps' definition of ``navigable waters'' was inadequate because it
did not include tributaries or coastal marshes above the mean high tide
mark or wetlands above the ordinary high water mark. The District Court
held that the term ``navigable waters'' is not limited to the
traditional tests of navigability and ordered the Corps to revoke its
definition and publish a new one ``clearly recognizing the full
regulatory mandate of the Water Act.'' Natural Resources Defense
Council, Inc. v. Callaway, 392 F. Supp. 685 (D.D.C. 1975).
 In response to this decision, the Corps issued interim regulations
in 1975 that defined the term ``navigable waters'' to include
periodically inundated coastal wetlands contiguous with or adjacent to
navigable waters, periodically inundated freshwater wetlands contiguous
with or adjacent to navigable waters, and, as in the EPA's 1973
regulations, certain intrastate waters based on non-transportation
impacts on interstate commerce. The Corps revised the definition in
1977 to encompass traditional navigable waters, tributaries to
navigable waters, interstate waters, adjacent wetlands to those
categories of waters, and ``[a]ll other waters'' the ``degradation or
destruction of which could affect interstate commerce.'' 42 FR 37122,
37144 (Jul. 19, 1977).
 The EPA and the Corps have maintained separate regulations defining
the statutory term ``waters of the United States,'' but the text of the
regulations has been virtually identical starting in 1986.\6\ In 1986,
for example, the Corps consolidated and recodified its regulations to
align with clarifications that the EPA had previously promulgated. See
51 FR 41206 (Nov. 13, 1986). While the Corps stated in 1986 that the
recodified regulation neither reduced nor expanded jurisdiction, its
previous exclusion for ditches was moved from the regulatory text to
the final rule preamble. Id. at 41216-17. And the Corps added to the
preamble what later became known as the ``Migratory Bird Rule,'' which
claimed jurisdiction over any waters which are or may be used by birds
protected by migratory bird treaties, waters which may be used as
habitat for birds flying across state lines, waters which may be used
by endangered species, and waters used to
[[Page 22255]]
irrigate crops sold in interstate commerce. Id. at 41217.
---------------------------------------------------------------------------
 \6\ For convenience, the agencies generally refer to the Corps'
regulations throughout this notice at 33 CFR 328.3. The EPA's
codification of the definition of ``waters of the United States'' is
found at 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 Part 300. This final rule
also codifies the definition of ``waters of the United States'' in a
new section 120.2.
---------------------------------------------------------------------------
 The 1986 regulatory text identified the following as waters of the
United States:
 All traditional navigable waters,\7\ interstate waters,
and the territorial seas;
---------------------------------------------------------------------------
 \7\ ``Traditional navigable waters'' (or waters that are
traditionally understood as navigable) refers to 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 subject
to the ebb and flow of the tide.
---------------------------------------------------------------------------
 All impoundments of jurisdictional waters;
 All ``other waters'' such as lakes, ponds, and sloughs the
``use, degradation or destruction of which could affect interstate or
foreign commerce'';
 Tributaries of traditional navigable waters, interstate
waters, impoundments, or ``other waters''; and,
 Wetlands adjacent to traditional navigable waters,
interstate waters, the territorial seas, impoundments, tributaries, or
``other waters'' (other than waters that are themselves wetlands).
33 CFR 328.3(a)(1)-(7) (1987). The 1986 regulation also excluded
``waste treatment systems'' from the definition of ``waters of the
United States,'' consistent with the EPA's regulatory definition. Id.
at 328.3 (a)(7), (b) (1987); see also 44 FR 32854 (June 7, 1979).
 On August 25, 1993, the agencies amended the regulatory definition
of ``waters of the United States'' to categorically exclude ``prior
converted croplands.'' 58 FR 45008, 45031 (Aug. 25, 1993) (``1993
Rule'') (codified at 33 CFR 328.3(a)(8) (1994)). The stated purpose of
the amendment was to promote ``consistency among various federal
programs affecting wetlands,'' in particular the Food Security Act of
1985 (FSA) programs implemented by the U.S. Department of Agriculture
(USDA) and the CWA programs implemented by the agencies.\8\ 58 FR
45031. The agencies did not include a definition of ``prior converted
cropland'' in the text of the Code of Federal Regulations but noted in
the preamble to the 1993 Rule that the term was defined at that time by
the USDA National Food Security Act Manual (NFSAM). Id. The agencies at
that time also declined to establish regulatory text specifying when
the prior converted cropland designation is no longer applicable. In
the preamble to the 1993 Rule, the agencies stated that ``[t]he Corps
and EPA will use the [Natural Resources Conservation Service's]
provisions on `abandonment,' thereby ensuring that PC cropland that is
abandoned within the meaning of those provisions and which exhibit[s]
wetlands characteristics will be considered wetlands subject to Section
404 regulation.'' Id. at 45034. The agencies summarized these
abandonment provisions by explaining that prior converted cropland
which meets wetland criteria is considered to be abandoned unless: At
least once in every five years the area 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.
---------------------------------------------------------------------------
 \8\ Title XII of the Food Security Act of 1985, as amended,
encourages participants in USDA programs to adopt land management
measures by linking eligibility for USDA program benefits to farming
practices on highly erodible land and wetlands (i.e., the wetland
conservation provisions). USDA policy guidance regarding
implementation of the wetland conservation provisions is found in
the current edition of the Natural Resource Conservation Service
National Food Security Act Manual (NFSAM), including the procedures
for how to delineate wetlands and make wetland determinations in
accordance with Subpart C of 7 CFR part 12. Due to the unique
statutory provisions of the FSA, USDA wetland determinations may
identify certain areas as exempt under the 1985 Act but remain
subject to the requirements of the CWA. To avoid potential
confusion, USDA clearly informs program participants that USDA
wetland determinations are for purposes of implementing the wetland
conservation provisions only, and that participants should contact
the Corps for clarification as to whether a particular activity will
require a CWA section 404 permit.
---------------------------------------------------------------------------
 Congress amended the FSA wetland conservation provisions in 1996 to
state that USDA certifications of eligibility for program benefits
(e.g., determinations by the Natural Resources Conservation Service
(NRCS) that particular areas constitute prior converted cropland)
``shall remain valid and in effect as long as the area is devoted to an
agricultural use or until such time as the person affected by the
certification requests review of the certification by the Secretary [of
Agriculture].'' Public Law 104-127, 322(a)(4), 110 Stat. 888 (1996); 16
U.S.C. 3822(a)(4). Thus, for purposes of farm program eligibility, the
1996 amendments designate as prior converted cropland those areas that
may not have qualified for the CWA exclusion under the abandonment
principles from the 1993 preamble, so long as such areas remain in
agricultural use. The agencies did not update their prior converted
cropland regulations for purposes of the CWA following the 1996
amendments to wetland conservation provisions of the FSA, as those
regulations neither defined prior converted cropland nor specified when
a valid prior converted cropland determination might cease to be valid.
However, in 2005, the Army and USDA issued a joint Memorandum to the
Field (the 2005 Memorandum) in an effort to again align the CWA section
404 program with the FSA amendments.\9\ The 2005 Memorandum provided
that a ``certified [prior converted] determination made by [USDA]
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.'' 2005 Memorandum at 4.
---------------------------------------------------------------------------
 \9\ Natural Resources Conservation Service and U.S. Army Corps
of Engineers. Memorandum to the Field on Guidance on Conducting
Wetland Determinations for the Food Security Act of 1985 and section
404 of the Clean Water Act (Feb. 25, 2005), available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2508.
---------------------------------------------------------------------------
 The 2005 Memorandum did not clearly address the abandonment
principle that the agencies had been implementing since the 1993
rulemaking. The change in use policy was also never promulgated as a
rule and was declared unlawful by one district court because it
effectively modified the 1993 preamble language without any rulemaking
process. New Hope Power Co. v. U.S. Army Corps of Eng'rs, 746 F. Supp.
2d 1272, 1282 (S.D. Fla. 2010).
3. U.S. Supreme Court Decisions
 From the earliest rulemaking efforts following adoption of the 1972
CWA amendments, to the agencies' most recent attempt to define ``waters
of the United States'' in 2015, the sparse statutory definition has
spurred substantial litigation testing the meaning of the phrase.
Hundreds of cases and dozens of courts have attempted to discern the
intent of Congress when crafting the phrase. See, e.g., Rapanos v.
United States, 547 U.S. 715, 739 (2006) (Scalia, J., plurality)
(briefly summarizing case history). The federal courts have established
different analytical frameworks to interpret the phrase, and the
applicable test may differ from State to State. See, e.g., Memorandum
from Dick Pedersen, President of the Environmental Council of the
States (ECOS) of September 11, 2014, Concerning Waters of the United
States under the Act at 2-23 (2014) (hereinafter, the ``ECOS
Memorandum''), available at http://acoel.org/file.axd?file=2014%2f9%2fWaters+of+the+U+S+Final+9_11_14.pdf
(summarizing case history following Rapanos).
 As part of this complex litigation history, three key U.S. Supreme
Court decisions have interpreted the term
[[Page 22256]]
``waters of the United States'' and its implementing regulations and
serve as guideposts for the agencies' interpretation of the phrase
``waters of the United States.'' In 1985, the Supreme Court deferred to
the Corps' assertion of jurisdiction over wetlands actually abutting a
traditional navigable water in Michigan, stating that adjacent wetlands
may be regulated as waters of the United States because they are
``inseparably bound up'' with navigable waters and ``in the majority of
cases'' have ``significant effects on water quality and the aquatic
ecosystem'' in those waters. United States v. Riverside Bayview Homes,
474 U.S. 121, 131-35 & n.9 (1985). The Court 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 . . . . Where on this continuum to find the limit of
`waters' is far from obvious.'' Id. at 132. The Court acknowledged the
``inherent difficulties of defining precise bounds to regulable
waters,'' and deferred to the agencies' interpretation that the close
ecological relationship between adjacent wetlands and traditional
navigable waters provided a legal justification for treating wetlands
as waters. Id. at 134. The Court also ``conclude[d] 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.'' Id. at 135.
 The Supreme Court again addressed the definition of ``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). In SWANCC, the
Court rejected a claim of federal jurisdiction over nonnavigable,
isolated, intrastate ponds that lack a sufficient connection to
traditional navigable waters, noting that the term ``navigable'' must
be given meaning within the context and application of the statute. Id.
The Court held that interpreting the statute to extend to nonnavigable,
isolated, intrastate ponds that lack a sufficient connection to
traditional navigable waters would invoke the outer limits of Congress'
power under the Commerce Clause. Id. at 172. Where an administrative
interpretation of a statute presses against the outer limits of
Congress' constitutional authority, the Court explained, it expects a
clear statement from Congress that it intended that result, and even
more so when the broad interpretation authorizes federal encroachment
upon a traditional State power. Id. The CWA contains no such clear
statement. Id. at 174.
 In January 2003, the EPA and the Corps issued joint guidance
interpreting the Supreme Court decision in SWANCC.\10\ The guidance
indicated that SWANCC focused on nonnavigable, isolated, intrastate
waters, and called for field staff to coordinate with their respective
Corps or EPA Headquarters on jurisdictional determinations that
asserted jurisdiction over such waters. The agencies at that time
focused their interpretation of SWANCC to its facts, and applied the
decision narrowly as restricting the exercise of federal jurisdiction
solely based on the Migratory Bird Rule.
---------------------------------------------------------------------------
 \10\ See U.S. EPA and U.S. Army Corps of Engineers. Legal
Memoranda Regarding Solid Waste Agency of Northern Cook County
(SWANCC) v. United States (Jan. 15, 2003), available at https://www.epa.gov/sites/production/files/2016-04/documents/swancc_guidance_jan_03.pdf.
---------------------------------------------------------------------------
 The Court most recently interpreted the term ``waters of the United
States'' in Rapanos v. United States, 547 U.S. 715 (2006). Rapanos
involved two consolidated cases in which the CWA had been applied to
wetlands located near man-made ditches that were ultimately connected
to traditional navigable waters. All members of the Court agreed that
the term ``waters of the United States'' encompasses some waters that
are not navigable in the traditional sense.
 A four-Justice plurality interpreted the term ``waters of the
United States'' to ``include[ ] only those relatively permanent,
standing or continuously flowing bodies of water `forming geographic
features' that are described in ordinary parlance as `streams[,] . . .
oceans, rivers, [and] lakes,' '' Rapanos, 547 U.S. at 739 (Scalia, J.,
plurality) (quoting Webster's New International Dictionary 2882 (2d ed.
1954)), and ``wetlands with a continuous surface connection'' to a
``relatively permanent body of water connected to traditional
interstate navigable waters.'' Id. at 742. The plurality explained that
``[w]etlands with only an intermittent, physically remote hydrologic
connection to `waters of the United States' do not implicate the
boundary-drawing problem of Riverside Bayview,'' and thus do not have
the ``necessary connection'' to covered waters that triggers CWA
jurisdiction. Id. at 742. The plurality also 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).
 In a concurring opinion, Justice Kennedy 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.''
Rapanos, 547 U.S. at 759 (Kennedy, J., concurring in the judgment)
(citing SWANCC, 531 U.S. at 167, 172). He stated that adjacent wetlands
possess the requisite significant nexus 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 780.
 Following Rapanos, on June 7, 2007, the agencies issued joint
guidance entitled ``Clean Water Act Jurisdiction Following the U.S.
Supreme Court's Decision in Rapanos v. United States and Carabell v.
United States'' to address the waters at issue in that decision. The
guidance did not change the codified definition of ``waters of the
United States.'' The guidance indicated that the agencies would assert
jurisdiction over traditional navigable waters and their adjacent
wetlands, relatively permanent nonnavigable tributaries of traditional
navigable waters and wetlands that abut them, nonnavigable tributaries
that are not relatively permanent if they have a significant nexus with
a traditional navigable water, and wetlands adjacent to nonnavigable
tributaries that are not relatively permanent if they have a
significant nexus with a traditional navigable water. The guidance was
reissued with minor changes on December 2, 2008 (hereinafter, the
``Rapanos Guidance'').\11\ After issuance of the Rapanos Guidance,
Members of Congress, developers, farmers, State and local governments,
environmental organizations, energy companies, and others asked the
agencies to replace the guidance with a regulation that would provide
clarity and certainty regarding the scope of the waters federally
regulated under the CWA.
---------------------------------------------------------------------------
 \11\ See U.S. EPA and 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 at 1 (Dec. 2,
2008) (``Rapanos Guidance''), available at https://www.epa.gov/sites/production/files/2016-02/documents/cwa_jurisdiction_following_rapanos120208.pdf.
---------------------------------------------------------------------------
 Since Rapanos, litigation has continued to confuse the regulatory
landscape. See, e.g., ECOS Memorandum at 2-23. The Supreme
[[Page 22257]]
Court also has twice weighed in on topics related to the agencies'
implementation of their authorities under the CWA to help clarify
federal authority in this area. In each case, members of the Court
noted the longstanding confusion regarding the scope of federal
jurisdiction under the CWA and the importance of providing clear
guidance to the regulated community. In 2012, for example, the Supreme
Court unanimously rejected the EPA's longstanding position that
compliance orders issued under the CWA to force property owners to
restore wetlands are not judicially reviewable as final agency actions.
See Sackett v. EPA, 566 U.S. 120, 131 (2012). In a concurring opinion,
Justice Alito referred to the jurisdictional reach of the CWA as
``notoriously unclear'' and noted that the Court's decision provided
only ``a modest measure of relief.'' Id. at 133 (Alito, J., concurring)
(``For 40 years, Congress has done nothing to resolve this critical
ambiguity, and the EPA has not seen fit to promulgate a rule providing
a clear and sufficiently limited definition of the phrase [`waters of
the United States']'').
 In 2016, the Supreme Court in a unanimous opinion rejected the
Corps' longstanding position that jurisdictional determinations issued
by the Corps were not judicially reviewable as final agency actions.
Writing for the Court, the Chief Justice recognized that it ``is often
difficult to determine whether a particular piece of property contains
waters of the United States, but there are important consequences if it
does.'' U.S. Army Corps of Eng'rs v. Hawkes Co., 136 S. Ct. 1807, 1812
(2016). Given those important consequences, the Court held that
jurisdictional determinations are subject to immediate judicial review
when made. Justice Kennedy authored a concurring opinion, ``not to
qualify what the Court says but to point out that, based on the
Government's representations in this case, the reach and systemic
consequences of the Clean Water Act remain a cause for concern.'' Id.
at 1816-17 (referring to the ``ominous reach'' of the Act). On remand,
the lower court found that the Corps' assertion of jurisdiction over a
peat farm more than 90 miles from the nearest traditional navigable
water based on the ``significant nexus'' test described in the
agencies' Rapanos Guidance was ``arbitrary and capricious.'' Hawkes Co.
v. U.S. Army Corps of Eng'rs, No. 13-107 ADM/TNL, 2017 U.S. Dist. LEXIS
10680 at *33 (D. Minn. Jan. 24, 2017).
4. The 2015 Rule
 On June 29, 2015, the agencies issued a final rule (80 FR 37054)
amending various portions of the CFR that set forth a definition of
``waters of the United States,'' a term contained in the CWA's
definition of ``navigable waters,'' 33 U.S.C. 1362(7). One of the
stated purposes of the 2015 Rule was to ``increase CWA program
predictability and consistency by clarifying the scope of `waters of
the United States' protected under the Act.'' 80 FR 37054. The 2015
Rule defined the geographic scope of the CWA by placing waters into
three categories: (A) Waters that are categorically ``jurisdictional by
rule'' in all instances (i.e., without the need for any 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. Waters considered
``jurisdictional by rule'' included (1) 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) 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.'' See 80 FR 37104.
 The 2015 Rule relied on a scientific literature review--the
Connectivity Report \12\--to support exerting federal jurisdiction over
certain waters. See 80 FR 37065 (``[T]he agencies interpret the scope
of `waters of the United States' protected under the CWA based on the
information and conclusions in the [Connectivity] Report . . . .'').
Although the agencies acknowledged that science cannot dictate where to
draw the line of federal jurisdiction, see, e.g., id. at 37060,
notwithstanding that qualifier, the agencies relied on the Connectivity
Report extensively in establishing the 2015 Rule's definition of
``waters of the United States.'' See id. at 37057 (``The [Connectivity]
Report provides much of the technical basis for [the] rule.'').
---------------------------------------------------------------------------
 \12\ U.S. EPA. Connectivity of Streams and Wetlands to
Downstream Waters: A Review and Synthesis of the Scientific Evidence
(Jan. 2015) (EPA/600/R-14/475F).
---------------------------------------------------------------------------
 The 2015 Rule added new definitions of key terms such as
``tributaries'' and revised previous definitions of terms such as
``adjacent'' (by adding a new definition of ``neighboring'' that is
used in the definition of ``adjacent'') that would determine whether
waters were ``jurisdictional by rule.'' See 80 FR 37105. Specifically,
a ``tributary'' under the 2015 Rule is a water that contributes flow,
either directly or through another water, to a water identified in the
first three categories of ``jurisdictional by rule'' waters that is
characterized by the presence of the ``physical indicators'' of a bed
and banks and an ordinary high water mark. According to the 2015 Rule's
preamble, ``[t]hese physical indicators demonstrate there is volume,
frequency, and duration of flow sufficient to create a bed and banks
and an ordinary high water mark, and thus to qualify as a tributary.''
Id.\13\ Tributaries under the 2015 Rule could be natural, man-altered,
or man-made, and do not lose their status as a tributary if, for any
length, there is one or more constructed breaks (such as bridges,
culverts, pipes, or dams), or one or more natural breaks (such as
wetlands along the run of a stream, debris piles, boulder fields, or a
stream that flows underground) so long as a bed and banks and an
ordinary high water mark could be identified upstream of the break. Id.
at 37105-06.
---------------------------------------------------------------------------
 \13\ The 2015 Rule did not delineate jurisdiction specifically
based on categories with established scientific meanings such as
ephemeral, intermittent, and perennial waters that are based on the
source of the water and nature of the flow. See 80 FR 37076 (``Under
the rule, flow in the tributary may be perennial, intermittent, or
ephemeral.''). Under the 2015 Rule, tributaries also did not need to
possess any specific volume, frequency, or duration of flow, or to
contribute flow to a traditional navigable water in any given year
or specific time period.
---------------------------------------------------------------------------
 In the 2015 Rule, the agencies did not expressly amend the
longstanding definition of ``adjacent'' (defined as ``bordering,
contiguous, or neighboring''), but the agencies added, for the first
time, a definition of ``neighboring'' that changed the meaning of
``adjacent.'' The 2015 Rule defined ``neighboring'' to encompass all
waters located within 100 feet of the ordinary high water mark of a
category (1) through (5) ``jurisdictional by rule'' water; all waters
located within the 100-year floodplain of a category (1) through (5)
``jurisdictional by rule'' water and not more than 1,500 feet from the
ordinary high water mark of such water; all waters located within 1,500
feet of the high tide line of a category (1) through (3)
``jurisdictional by rule'' water; and all waters within 1,500 feet of
the ordinary high water mark of the Great Lakes. 80 FR 37105. The
entire water would be considered ``neighboring'' if any portion of it
lies
[[Page 22258]]
within one of these zones. See id. These quantitative measures did not
appear in the proposed rule and, as discussed in the 2019 Rule and
below, the agencies concluded that they were not sufficiently supported
in the administrative record for the final rule.
 In addition to the six categories of ``jurisdictional by rule''
waters, the 2015 Rule identified certain waters that would be subject
to a case-specific analysis to determine if they had a ``significant
nexus'' to a water that is jurisdictional. 80 FR 37104-05. The first
category consists of five specific types of waters in specific regions
of the country: Prairie potholes, Carolina and Delmarva bays, pocosins,
western vernal pools in California, and Texas coastal prairie wetlands.
Id. at 37105. The second category consists of all waters located within
the 100-year floodplain of any category (1) through (3)
``jurisdictional by rule'' water and all waters located within 4,000
feet of the high tide line or ordinary high water mark of any category
(1) through (5) ``jurisdictional by rule'' water. Id. These
quantitative measures did not appear in the proposed rule and, as
discussed in the 2019 Rule and below, the agencies concluded that they
were not sufficiently supported in the administrative record for the
final 2015 Rule.
 The 2015 Rule defined ``significant nexus'' to mean a water,
including wetlands, that either alone or in combination with other
similarly situated waters in the region, significantly affected the
chemical, physical, or biological integrity of a category (1) through
(3) ``jurisdictional by rule'' water. 80 FR 37106. ``For an effect to
be significant, it must be more than speculative or insubstantial.''
Id. The term ``in the region'' meant ``the watershed that drains to the
nearest'' primary water. Id. This definition was different from the
test articulated by the agencies in their 2008 Rapanos Guidance. That
guidance interpreted ``similarly situated'' to include all wetlands
(not waters) adjacent to the same tributary.
 Under the 2015 Rule, to determine whether a water, alone or in
combination with similarly situated waters across the watershed of the
nearest primary water, had a significant nexus, one had to consider
nine functions such as sediment trapping, runoff storage, provision of
life cycle dependent aquatic habitat, and other functions. 80 FR 37106.
A single function performed by a water, alone or together with
similarly situated waters in the region, that contributed significantly
to the chemical, physical, or biological integrity of the nearest
category (1) through (3) ``jurisdictional by rule'' water was
sufficient to establish a significant nexus. Id. Taken together, the
enumeration of the nine functions and the more expansive consideration
of ``similarly situated waters in the region'' in the 2015 Rule meant
that the vast majority of water features in the United States may have
come within the jurisdictional purview of the Federal government.\14\
---------------------------------------------------------------------------
 \14\ ``[T]he vast majority of the nation's water features are
located within 4,000 feet of a covered tributary, traditional
navigable water, interstate water, or territorial sea.'' U.S. EPA
and Department of the Army, Economic Analysis of the EPA-Army Clean
Water Rule at 11 (May 20, 2015) (``2015 Rule Economic Analysis'')
(Docket ID: EPA-HQ-OW-2011-0880-20866), available at https://www.regulations.gov/document?D=EPA-HQ-OW-2011-0880-20866.
---------------------------------------------------------------------------
 The 2015 Rule also retained exclusions from the definition of
``waters of the United States'' for prior converted cropland and waste
treatment systems. 80 FR 37105. In addition, the agencies codified
several exclusions that, in part, reflected longstanding agency
practice and added others such as ``puddles'' and ``swimming pools'' in
response to concerns raised by stakeholders during the public comment
period on the proposed 2015 Rule. Id. at 37096-98, 37105.
 Following the 2015 Rule's publication, 31 States \15\ and numerous
non-state parties, including environmental groups and groups
representing farming, recreational, forestry, and other interests,
filed complaints and petitions for review in multiple federal district
\16\ and appellate \17\ courts challenging the 2015 Rule. In those
cases, the challengers alleged numerous procedural deficiencies in the
development and promulgation of the 2015 Rule and substantive
deficiencies in the 2015 Rule itself. Some challengers argued that the
2015 Rule was too expansive, while others argued that it excluded too
many waters from federal jurisdiction.
---------------------------------------------------------------------------
 \15\ Alabama, Alaska, Arizona, Arkansas, Colorado, Florida,
Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Michigan,
Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico
(Environment Department and State Engineer), North Carolina
(Department of Environment and Natural Resources), North Dakota,
Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas,
Utah, West Virginia, Wisconsin, and Wyoming. Iowa joined the legal
challenge later in the process, bringing the total to 32 States.
Colorado, New Mexico, and Wisconsin have since withdrawn from
litigation against the 2015 Rule.
 \16\ U.S. District Courts for the Northern and Southern
Districts of Georgia, District of Minnesota, District of North
Dakota, Southern District of Ohio, Northern District of Oklahoma,
Southern District of Texas, District of Arizona, Northern District
of Florida, District of the District of Columbia, Western District
of Washington, Northern District of California, and Northern
District of West Virginia. In April 2019, an additional challenge
against the 2015 Rule was filed in the U.S. District Court for the
District of Oregon.
 \17\ U.S. Courts of Appeals for the Second, Fifth, Sixth,
Eighth, Ninth, Tenth, Eleventh, and District of Columbia Circuits.
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 The day before the 2015 Rule's August 28, 2015 effective date, the
U.S. District Court for the District of North Dakota preliminarily
enjoined the 2015 Rule in the 13 States that challenged the rule in
that court.\18\ The district court found those States were ``likely to
succeed'' on the merits of their challenge to the 2015 Rule because,
among other reasons, ``it appears likely that the EPA has violated its
Congressional grant of authority in its promulgation of the Rule.''
North Dakota v. EPA, 127 F. Supp. 3d 1047, 1051 (D.N.D. 2015). In
particular, the court noted concern that the 2015 Rule's definition of
``tributary'' ``includes vast numbers of waters that are unlikely to
have a nexus to navigable waters.'' Id. at 1056. Further, the court
found that ``it appears likely the EPA failed to comply with
[Administrative Procedure Act (APA)] requirements when promulgating the
Rule,'' suggesting that certain distance-based measures were not a
logical outgrowth of the proposal to the 2015 Rule. Id. at 1051, 1058.
No party sought an interlocutory appeal.
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 \18\ Alaska, Arizona, Arkansas, Colorado, Idaho, Missouri,
Montana, Nebraska, Nevada, New Mexico, North Dakota, South Dakota,
and Wyoming. Iowa's motion to intervene in the case was granted
after issuance of the preliminary injunction. In May 2019, the court
granted motions from Colorado and New Mexico to withdraw from the
litigation and lifted the preliminary injunction as to Colorado and
New Mexico. Order, North Dakota v. EPA, No. 3:15-cv-00059 (D.N.D.
May 14, 2019). At the same time, the court stated that the
preliminary injunction would remain in effect as to a plaintiff-
intervenor that represents ten counties in New Mexico. The agencies
filed a motion seeking clarification of the applicability of the
court's preliminary injunction to those ten counties in New Mexico.
Defendants' Motion for Clarification Regarding the Scope of the
Court's Preliminary Injunction, North Dakota v. EPA, No. 3:15-cv-
00059 (D.N.D. May 24, 2019). As of the time of signature of this
final rule, that motion is pending before the court.
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 The numerous petitions for review filed in the courts of appeals
were consolidated in the U.S. Court of Appeals for the Sixth Circuit.
In that litigation, State and industry petitioners raised concerns
about whether the 2015 Rule violated the Constitution and the CWA and
whether its promulgation violated the APA and other statutes.
Environmental petitioners also challenged the 2015 Rule, claiming in
part that the 2015 Rule was too narrow because of the distance
limitations and other issues. On October 9, 2015, approximately six
weeks after the 2015 Rule took effect in the 37 States, the District of
Columbia, and U.S.
[[Page 22259]]
Territories that were not subject to the preliminary injunction issued
by the District of North Dakota, the Sixth Circuit stayed the 2015 Rule
nationwide after concluding, among other things, that State petitioners
had demonstrated ``a substantial possibility of success on the merits
of their claims.'' In re EPA & Dep't of Def. Final Rule, 803 F.3d 804,
807 (6th Cir. 2015) (``In re EPA'').
 On January 13, 2017, the U.S. Supreme Court granted certiorari on
the question of whether the courts of appeals have original
jurisdiction to review challenges to the 2015 Rule. See Nat'l Ass'n of
Mfrs. v. Dep't of Def., 137 S. Ct. 811 (2017). The Sixth Circuit
granted petitioners' motion to hold in abeyance the briefing schedule
in the litigation challenging the 2015 Rule pending a Supreme Court
decision on the question of the court of appeals' jurisdiction. On
January 22, 2018, the Supreme Court, in a unanimous opinion, held that
the 2015 Rule is subject to direct review in the district courts. Nat'l
Ass'n of Mfrs. v. Dep't of Def., 138 S. Ct. 617, 624 (2018). Throughout
the pendency of the Supreme Court litigation (and for a short time
thereafter), the Sixth Circuit's nationwide stay remained in effect. In
response to the Supreme Court's decision, on February 28, 2018, the
Sixth Circuit lifted the stay and dismissed the corresponding petitions
for review. See In re Dep't of Def. & EPA Final Rule, 713 Fed. Appx.
489 (6th Cir. 2018).
 Following the Supreme Court's jurisdictional ruling, district court
litigation regarding the 2015 Rule resumed. At this time, the 2015 Rule
continues to be subject to a preliminary injunction issued by the
District of North Dakota as to 12 States: Alaska, Arizona, Arkansas,
Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, North Dakota, South
Dakota, and Wyoming.\19\ The 2015 Rule also is subject to a preliminary
injunction issued by the U.S. District Court for the Southern District
of Georgia as to 11 more States: Georgia, Alabama, Florida, Indiana,
Kansas, Kentucky, North Carolina, South Carolina, Utah, West Virginia,
and Wisconsin. Georgia v. Pruitt, 326 F. Supp. 3d 1356, 1364 (S.D. Ga.
2018). The Southern District of Georgia subsequently issued an order
remanding the 2015 Rule to the agencies, finding that the 2015 Rule
exceeded the agencies' statutory authority under the CWA and was
promulgated in violation of the APA. Georgia v. Wheeler, No. 2:15-cv-
079, 2019 WL 3949922 (S.D. Ga. Aug. 21, 2019). ``[I]n light of the
serious defects identified,'' the court retained its injunction against
the 2015 Rule. Id. at *36.\20\
---------------------------------------------------------------------------
 \19\ As of the date this final rule was signed, the
applicability and scope of the North Dakota district court's
preliminary injunction in New Mexico is unclear. See supra note 18.
 \20\ The Southern District of Georgia later denied as moot
plaintiffs' motions for reconsideration asking the court to vacate,
rather than remand, the 2015 Rule. Order, Georgia v. Wheeler, No.
2:15-cv-079 (S.D. Ga. Jan. 3, 2020).
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 In September 2018, the U.S. District Court for the Southern
District of Texas issued a preliminary injunction against the 2015 Rule
in response to motions filed by the States of Texas, Louisiana, and
Mississippi and several business associations, finding that enjoining
the rule would provide ``much needed governmental, administrative, and
economic stability'' while the rule undergoes judicial review. See
Texas v. EPA, No. 3:15-cv-162, 2018 WL 4518230, at *1 (S.D. Tex. Sept.
12, 2018). The court observed that if it did not temporarily enjoin the
rule, ``it risks asking the states, their governmental subdivisions,
and their citizens to expend valuable resources and time
operationalizing a rule that may not survive judicial review.'' Id. In
May 2019, the court remanded the 2015 Rule to the agencies on the
grounds that the rule violated the APA. Specifically, the court found
that the rule violated the APA's notice and comment requirements
because: (1) The 2015 Rule's definition of ``adjacent'' waters (which
relied on distance-based limitations) was not a ``logical outgrowth''
of the proposal's definition of ``adjacent'' waters (which relied on
ecologic and hydrologic criteria); and (2) the agencies denied
interested parties an opportunity to comment on the final version of
the Connectivity Report, which served as the technical basis for the
final rule. See Texas v. EPA, 389 F. Supp. 3d 497 (S.D. Tex. 2019).\21\
---------------------------------------------------------------------------
 \21\ The Southern District of Texas later denied plaintiffs'
motions for reconsideration urging the court to vacate, rather than
remand, the 2015 Rule. Order, Texas v. EPA, No. 3:15-cv-00162 (S.D.
Tex. Nov. 6, 2019).
---------------------------------------------------------------------------
 In July 2019, the U.S. District Court for the District of Oregon
issued a preliminary injunction against the 2015 Rule in the State of
Oregon. Order, Or. Cattlemen's Ass'n v. EPA, No. 19-00564 (D. Or. July
26, 2019). As a result, the 2015 Rule was enjoined in more than half of
the States.
 Three additional States (Ohio, Michigan, and Tennessee) sought a
preliminary injunction against the 2015 Rule in the U.S. District Court
for the Southern District of Ohio. In March 2019, the court denied the
States' motion, finding that the States had ``failed to demonstrate
that they will suffer imminent and irreparable harm absent an
injunction.'' See Ohio v. EPA, No. 2:15-cv-02467, 2019 WL 1368850 (S.D.
Ohio Mar. 26, 2019). The court subsequently denied the States' motion
for reconsideration of its order denying the preliminary injunction
motion, and the States have since filed an appeal of the court's order
in the Sixth Circuit. See Ohio v. EPA, No. 2:15-cv-02467, 2019 WL
1958650 (S.D. Ohio May 2, 2019); Plaintiffs' Notice of Appeal, Ohio v.
EPA, No. 2:15-cv-02467 (S.D. Ohio May 28, 2019).\22\
---------------------------------------------------------------------------
 \22\ Parties challenging the 2015 Rule in the U.S. District
Court for the Northern District of Oklahoma, including the State of
Oklahoma and the U.S. Chamber of Commerce, unsuccessfully sought a
motion for a preliminary injunction against the 2015 Rule and later
stipulated to a voluntary dismissal of the case. See Opinion &
Order, Oklahoma v. EPA, No. 4:15-cv-00381 (N.D. Okla. May 29, 2019);
Stipulation of Voluntary Dismissal, Oklahoma v. EPA, No. 4:15-cv-
00381 (N.D. Okla. Jan. 7, 2019). Following the effective date of the
2019 Rule, an additional motion for a preliminary injunction against
the 2015 Rule was denied as moot in the U.S. District Court for the
Western District of Washington. Order, Wash. Cattlemen's Ass'n v.
EPA, No. 19-00569 (W.D. Wash. Dec. 30, 2019).
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C. Executive Order 13778 and the ``Step One'' Rulemaking
 On February 28, 2017, the President issued Executive Order 13778
entitled ``Restoring the Rule of Law, Federalism, and Economic Growth
by Reviewing the `Waters of the United States' Rule.'' Section 1 of the
Executive Order states, ``[i]t is in the national interest to ensure
that the Nation's navigable waters are kept free from pollution, while
at the same time promoting economic growth, minimizing regulatory
uncertainty, and showing due regard for the roles of the Congress and
the States under the Constitution.'' The Executive Order directs the
EPA and the Army to review the 2015 Rule for consistency with the
policy outlined in Section 1 of the Order and to issue a proposed rule
rescinding or revising the 2015 Rule as appropriate and consistent with
law (Section 2). The Executive Order also directs the agencies to
``consider interpreting the term `navigable waters' . . . in a manner
consistent with'' Justice Scalia's plurality opinion in Rapanos v.
United States, 547 U.S. 715 (2006) (Section 3).
 On March 6, 2017, the agencies published a notice of intent to
review the 2015 Rule and provide notice of a forthcoming proposed
rulemaking consistent with the Executive Order. 82 FR 12532. Shortly
thereafter, the agencies announced that they would implement the
Executive Order in a two-step approach. On July 27, 2017,
[[Page 22260]]
the agencies published the ``Definition of `Waters of the United
States'--Recodification of Pre-Existing Rules'' notice of proposed
rulemaking (NPRM) (82 FR 34899) that proposed to repeal the 2015 Rule
and recodify the regulatory text that governed prior to the
promulgation of the 2015 Rule, consistent with Supreme Court decisions
and informed by applicable guidance documents and longstanding agency
practice. The agencies refer to this as the ``Step One'' rule. The
agencies invited comment on the NPRM over a 62-day period. On July 12,
2018, the agencies published a supplemental notice of proposed
rulemaking (SNPRM) to clarify, supplement, and seek additional comment
on the proposed repeal and recodification. 83 FR 32227. The agencies
invited comment on the SNPRM over a 30-day period.
 On October 22, 2019, the agencies published a final rule repealing
the 2015 Rule and recodifying the pre-existing regulations as an
interim matter until this final rule becomes effective. 84 FR 56626. In
developing the final Step One rule (referred to as the ``2019 Rule''),
the agencies reviewed approximately 690,000 public comments received on
the NPRM and approximately 80,000 comments received on the SNPRM from a
broad spectrum of interested parties. In the NPRM and SNPRM the
agencies sought comment on all aspects of the NPRM, the economic
analysis for the NPRM, and the SNPRM, including the repeal of the 2015
Rule, the recodification of the prior regulations, the considerations
underlying the proposal and agencies' reasons for the proposal, and the
agencies' proposed conclusions that the 2015 Rule exceeded the
agencies' authority under the CWA.
 The agencies finalized the 2019 Rule, which became effective
December 23, 2019, and repealed the 2015 Rule for four primary reasons.
First, the agencies concluded that the 2015 Rule did not implement the
legal limits on the scope of the agencies' authority under the CWA as
intended by Congress and reflected in Supreme Court cases, including
Justice Kennedy's articulation of the significant nexus test in
Rapanos. Second, the agencies concluded that in promulgating the 2015
Rule the agencies failed to adequately consider and accord due weight
to the policy of the Congress in CWA section 101(b) 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 . . . of land and water resources.'' 33 U.S.C.
1251(b). Third, the agencies repealed the 2015 Rule to avoid
interpretations of the CWA that push the envelope of their
constitutional and statutory authority absent a clear statement from
Congress authorizing the encroachment of federal jurisdiction over
traditional State land-use planning authority. Lastly, the agencies
concluded that the 2015 Rule's distance-based limitations suffered from
certain procedural errors and a lack of adequate record support. The
agencies found that these reasons, collectively and individually,
warranted repealing the 2015 Rule.
 At this time, the regulations defining the scope of federal CWA
jurisdiction are those portions of the CFR as they existed before the
amendments promulgated in the 2015 Rule. The agencies concluded that it
was appropriate as an interim matter to restore the pre-existing
regulations to provide regulatory certainty as the agencies considered
the proposed revised definition of ``waters of the United States'' and
because, as implemented, those prior regulations adhere more closely
than the 2015 Rule to the jurisdictional limits reflected in the
statute and case law. As anticipated in the 2019 Rule, this final rule
replaces the recodified pre-2015 regulations, upon its effective date.
 As of the time of signature of this final rule, challenges to the
agencies' 2019 Rule are pending in six district courts, wherein both
environmental and industry groups have either filed new complaints or
sought to supplement existing complaints to challenge the rule in whole
or in part. See New York v. Wheeler, No. 19-11673 (S.D.N.Y., complaint
filed Dec. 20, 2019); Wash. Cattlemen's Ass'n v. EPA, No. 2:19-cv-00569
(W.D. Wash., supplemental amended complaint filed Dec. 20, 2019);
Murray v. Wheeler, No. 1:19-cv-01498 (N.D.N.Y., complaint filed Dec. 4,
2019); S.C. Coastal Conservation League v. Wheeler, No. 2:19-cv-3006
(D.S.C., complaint filed Oct. 23, 2019); N.M. Cattle Growers' Ass'n v.
EPA, No. 1:19-cv-988 (D.N.M., complaint filed Oct. 22, 2019); Pierce v.
EPA, No. 0:19-cv-2193 (D. Minn., supplemental complaint filed Oct. 22,
2019).
D. Summary of Stakeholder Outreach and the ``Step Two'' Rulemaking
 Following the March 6, 2017 Federal Register notice announcing the
agencies' intent to review and rescind or revise the 2015 Rule, the
agencies initiated an effort to engage the public to hear perspectives
as to how the agencies could define ``waters of the United States,''
including creating a new website to provide information on the
rulemaking. See www.epa.gov/wotus-rule. On April 19, 2017, the agencies
held an initial Federalism consultation meeting with State and local
government officials as well as national organizations representing
such officials. The agencies also convened several additional meetings
with intergovernmental associations and their members to solicit input
on the future rule. The EPA, with participation from the Army,
initiated Tribal consultation on April 20, 2017, under the EPA Policy
on Consultation and Coordination with Indian Tribes. See Section VI for
further details on the agencies' consultations. The agencies considered
comments received from federalism and tribal consultations as they
developed this final rule.
 In addition to engaging State, tribal, and local officials through
federalism and tribal consultations, the agencies sought feedback on
the definition of ``waters of the United States'' from a broad audience
of stakeholders, including small entities (small businesses, small
organizations, and small government jurisdictions), through a series of
outreach webinars that were held September 9, 2017, through November
21, 2017, and through an in-person meeting for small entities on
October 23, 2017. A summary of these public listening sessions is
available in the docket (Docket Id. No. EPA-HQ-OW-2018-0149-0091) for
this rule. The webinars were tailored to specific sectors, including
agriculture (row crop, livestock, silviculture); conservation (hunters
and anglers); small entities (small businesses, small organizations,
small government jurisdictions); construction and transportation;
environment and public advocacy (including health and environmental
justice); mining; energy and chemical industry; scientific
organizations and academia; stormwater, wastewater management, and
drinking water agencies; and the general public.
 At the pre-proposal webinars and meetings with stakeholders, the
agencies provided a presentation and sought input on specific issues,
such as potential approaches to defining the phrases ``relatively
permanent'' waters and ``continuous surface connections'' as
articulated by the plurality opinion in Rapanos, as well as other
considerations addressing specific geomorphological features,
exclusions and exemptions, costs and benefits, and aquatic resource
data that the agencies might consider in the technical analyses for a
future rule. As part of this outreach effort, the agencies established
a public recommendations docket (Docket ID No. EPA-HQ-OW-2017-0480)
that opened
[[Page 22261]]
August 28, 2017, and closed November 28, 2017. Participant comments and
letters submitted represent a diverse range of interests, positions,
suggestions, and recommendations provided to the agencies. The agencies
received over 6,300 recommendations (available on Regulations.gov at
https://www.regulations.gov/docket?D=EPA-HQ-OW-2017-0480) that were
considered as the agencies developed the proposed revised definition of
``waters of the United States.'' The agencies also considered
recommendations as to how the agencies should define ``waters of the
United States'' that were submitted in public comments on the agencies'
proposed ``Step One'' rule (82 FR 34899, July 27, 2017) and the July
2018 SNPRM (83 FR 32227, July 12, 2018).
 The agencies continued their pre-proposal engagement with States
and Tribes via additional webinars and in-person meetings. On March 8
and 9, 2018, the agencies held an in-person State Co-Regulators
Workshop with representatives from nine States (Arizona, Arkansas,
Florida, Iowa, Maryland, Minnesota, Oregon, Pennsylvania, and Wyoming)
and convened a subsequent in-person meeting on March 22, 2018, with
representatives from all States at the spring meeting of the
Environmental Council of the States. The agencies also held an in-
person Tribal Co-Regulators Workshop on March 6 and 7, 2018, with
representatives from 20 tribes. These meetings were intended to seek
technical input as the agencies developed the proposed rule. The
agencies also sought pre-proposal input from Tribes through national
and regional tribal meetings, including through listening sessions at
the Tribal Land and Environment Forum (August 16, 2017 and August 15,
2018) and the National Congress of American Indians Annual Convention
(October 24, 2018).
 On December 12, 2018, the agencies signed the proposed rule to
revise the definition of ``waters of the United States,'' as the second
step of the comprehensive two-step process consistent with Executive
Order 13778. The proposal was published on February 14, 2019. 84 FR
4154. The agencies proposed to interpret the term ``waters of the
United States'' to encompass: Traditional navigable waters, including
the territorial seas; tributaries that contribute perennial or
intermittent flow to such waters; certain ditches; certain lakes and
ponds; impoundments of otherwise jurisdictional waters; and wetlands
adjacent to other jurisdictional waters. The 60-day public comment
period for the proposed revised definition of ``waters of the United
States'' (``Step Two'' Rule) closed on April 15, 2019.\23\
---------------------------------------------------------------------------
 \23\ The pre-publication of the proposed rule was published on
EPA's website on December 12, 2018, approximately 60 days prior to
its publication in the Federal Register and the date the formal
public comment period began.
---------------------------------------------------------------------------
 The agencies conducted a variety of stakeholder outreach on the
proposed rule upon its publication in the Federal Register. On February
14, 2019, the agencies held a public webcast to present key elements of
the proposed rule (see https://www.youtube.com/watch?v=ZZ6kFJasDhg&feature=youtu.be), and held a public hearing in
Kansas City, Kansas, on February 27 and 28, 2019, to hear feedback from
individuals from regulated industry sectors, environmental and
conservation organizations, State agencies, tribal governments, and
private citizens. The agencies also continued engagement with States
and Tribes through a series of in-person meetings with State and tribal
representatives in Kansas City, Kansas; Atlanta, Georgia; Albuquerque,
New Mexico; and Seattle, Washington during the public comment period
for the proposed rule. During these meetings, the agencies provided an
overview of the proposed rule, responded to clarifying questions from
participants, discussed implementation considerations, and heard
feedback on the agencies' interest in developing geospatial datasets of
jurisdictional waters. A transcript of the public hearing and related
materials and summaries of the State and tribal meetings can be found
in the docket for the final rule. At the request of individual Tribes,
the agencies also continued to hold staff-level and leader-to-leader
meetings with individual Tribes.
 In developing this final rule, the agencies reviewed and considered
approximately 620,000 comments received on the proposed rule from a
broad spectrum of interested parties. Commenters provided a wide range
of feedback on the various aspects of 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 resource and programmatic
assessment for the proposed rule, and the agencies' considerations for
developing geospatial datasets of jurisdictional waters in partnership
with other federal agencies, States, and Tribes. The agencies discuss
comments received and their responses in the applicable sections of
this final rule. A complete response to comments document is available
in the docket for this final rule at Docket ID No. EPA-HQ-OW-2018-0149.
 The agencies also engaged with the EPA's Science Advisory Board
(SAB) during the development of the rule on several occasions. The
agencies met with the SAB prior to the proposed rule and following
publication of the proposed rule to explain the basis for the rule and
to address the SAB's questions and initial observations. The SAB issued
a draft commentary on the proposed rule on December 31, 2019, and held
a public meeting on the matter on January 17, 2020. The SAB's draft
commentary asserted that the proposed rule did not fully incorporate
the Connectivity Report and offers no comparable body of peer reviewed
evidence to support this departure. As the agencies made clear in the
proposed rule preamble and explain in greater detail in this notice,
the agencies used the Connectivity Report to inform certain aspects of
the definition of ``waters of the United States,'' but recognize that
science cannot dictate where to draw the line between Federal and State
waters, as this is a legal question that must be answered based on the
overall framework and construct of the CWA. The SAB's draft also
addresses the absence of ``ground water protection;'' the exclusion of
``irrigation canals'' from regulatory jurisdiction; the exclusion of
``adjacent wetlands that do not abut or have a direct hydrologic
surface connection to otherwise jurisdictional waters;'' and the
absence of ``long term clarity'' as a result of the asserted lack of
scientific basis for the proposed rule.
 The relevant comments raised by the SAB were also raised by public
commenters throughout the rulemaking process, and as a result, have
been addressed by the agencies in the final rule, supporting documents,
and throughout this notice. In brief, however, the agencies note that
the final rule is consistent with the agencies' longstanding position
that ``waters of the United States'' do not include groundwater; that
the agencies do not use the term ``irrigation canals'' in the final
rule; that ``irrigation ditches'' constructed in uplands and
``irrigation return flows'' generally have been not been subject to CWA
regulatory requirements; and that the agencies have expanded
jurisdiction over certain ``adjacent wetlands'' compared to the
proposal to better incorporate common principles from the Rapanos
plurality and concurring opinions, that the final rule strikes a better
balance between the objective and policy in CWA sections 101(a) and
101(b), respectively; and that
[[Page 22262]]
the final rule is consistent with the text, structure, legislative
history, and applicable Supreme Court guidance. A memorandum
summarizing the agencies' interactions with the SAB and the SAB's draft
commentary are available in the docket for this final rule.
E. Overview of Legal Construct for the Final Rule
 As the preceding summary of the statutory and regulatory history
makes clear, the central term delineating the federal geographic scope
of authority under the CWA--``waters of the United States''--has been
the subject of debate and litigation for many years. The agencies are
promulgating a regulation to define ``waters of the United States''
adhering to Constitutional and statutory limitations, the policies and
objective of the CWA, and case law. The revised definition will allow
the regulatory agencies and the regulated community to protect
navigable waters from pollution while providing an implementable
approach to determining regulatory jurisdiction under the CWA. This
subsection summarizes the legal principles that inform the agencies'
final rule, and the following section (Section III) describes how the
agencies are applying those legal principles to support the final
revised definition of ``waters of the United States.''
1. Statutory Framework
 To determine the scope of executive branch authority under the CWA,
the agencies begin with the text of the statute. The objective of the
CWA, as established by Congress, is ``to restore and maintain the
chemical, physical, and biological integrity of the Nation's waters.''
33 U.S.C. 1251(a). As discussed in Section II.B, in order to meet that
objective, Congress declared two national water quality goals and
established several key policies that direct the work of the agencies.
Congress also envisioned a major role for the States in implementing
the CWA, carefully balancing the traditional power of States to
regulate land and water resources within their borders with the need
for national water quality regulation.
 The agencies have developed regulatory and non-regulatory programs
designed to ensure that the full statute is implemented as Congress
intended. See, e.g., Hibbs v. Winn, 542 U.S. 88, 101 (2004) (``A
statute should be construed so that effect is given to all its
provisions, so that no part will be inoperative or superfluous, void or
insignificant.''). This includes pursuing the overall ``objective'' of
the CWA to ``restore and maintain the chemical, physical, and
biological integrity of the Nation's waters,'' 33 U.S.C. 1251(a), while
implementing the specific ``policy'' directives from Congress to, among
other things, ``recognize, preserve, and protect the primary
responsibilities and rights of States to prevent, reduce, and eliminate
pollution'' and ``to plan the development and use . . . of land and
water resources.'' Id. at 1251(b); see also Webster's II, New Riverside
University Dictionary (1994) (defining ``policy'' as a ``plan or course
of action, as of a government[,] designed to influence and determine
decisions and actions;'' an ``objective'' is ``something worked toward
or aspired to: Goal'').\24\ The agencies therefore recognize a
distinction between the specific word choices of Congress, including
the need to develop regulatory and non-regulatory programs that aim to
accomplish the goals of the Act while implementing the specific policy
directives of Congress.\25\ To do so, the agencies must determine what
Congress had in mind when it defined ``navigable waters'' in 1972 as
``the waters of the United States.''
---------------------------------------------------------------------------
 \24\ The legislative history of the CWA further illuminates the
distinction between the terms ``policy'' and ``objective,'' or
``goal.'' As Congress drafted the 1972 CWA amendments, the Senate
bill set the ``no-discharge of pollutants into the navigable water
by 1985'' provision as a policy whereas the House bill set it as a
goal. The Act was ultimately passed with the ``no-discharge by
1985'' provision established as a goal. See 33 U.S.C 1251(a)(1).
During the House's consideration of the Conference Report,
Representative Robert E. Jones, Jr. captured the policy versus goal
distinction in section 101(a)(1) as follows: ``The objective of this
legislation is to restore and preserve for the future the integrity
of our Nation's waters. The bill sets forth as a national goal the
complete elimination of all discharges into our navigable waters by
1985, but . . . the conference report states clearly that achieving
the 1985 target date is a goal, not a national policy. As such, it
serves as a focal point for long-range planning, and for research
and development in water pollution control technology . . . . While
it is our hope that we can succeed in eliminating all discharge into
our waters by 1985, without unreasonable impact on the national
life, we recognized in this report that too many imponderables
exist, some still beyond our horizons, to prescribe this goal today
as a legal requirement.'' 118 Cong. Rec. H. 33749 (daily ed. October
4, 1972).
 \25\ See, e.g., Nat'l Fed'n of Indep. Bus. v. Sebelius, 567 U.S.
519, 544 (2012) (``Where Congress uses certain language in one part
of a statute and different language in another, it is generally
presumed that Congress acts intentionally.''); Russello v. United
States, 464 U.S. 16, 23 (1983) (``[Where] Congress includes
particular language in one section of a statute but omits it in
another section of the same Act, it is generally presumed that
Congress acts intentionally and purposely in the disparate inclusion
or exclusion.'')
---------------------------------------------------------------------------
 Congress' authority to regulate navigable waters under the CWA
derives from its power to regulate the ``channels of interstate
commerce'' under the Commerce Clause. Gibbons v. Ogden, 22 U.S. (9
Wheat.) 1 (1824). In United States v. Lopez, the Supreme Court
explained that the Commerce Clause gives Congress the authority to
regulate in three areas: The ``channels of interstate commerce,'' the
``instrumentalities of interstate commerce,'' and those additional
activities having ``a substantial relation to interstate commerce.''
514 U.S. 549, 558-59 (1995). Some commenters stated that Congress'
authority over ``waters of the United States'' is not tethered to
navigable channels of interstate commerce, but is also derived from its
authority over the ``instrumentalities of interstate commerce'' and
activities that ``substantially affect'' interstate commerce. See id.
The agencies disagree with these comments. The Supreme Court made clear
in SWANCC that the term ``navigable'' indicates ``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.'' 531 U.S. 159, 172 (2001). The
Court further explained that nothing in the legislative history of the
Act provides any indication that ``Congress intended to exert anything
more than its commerce power over navigation.'' Id. at 168 n.3. The
Supreme Court, however, has recognized that Congress intended ``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 SWANCC, 531 U.S. at 167.
 The classical understanding of the term ``navigable'' was first
articulated by the Supreme Court in The Daniel Ball:
 Those rivers must be regarded as public navigable rivers in law
which are navigable in fact. And they are navigable in fact when
they are used, or are susceptible of being used, in their ordinary
condition, as highways of commerce, over which trade and travel are
or may be conducted in the customary modes of trade and travel on
water. And they constitute navigable waters of the United States
within the meaning of the acts of Congress, in contradistinction
from the navigable waters of the States, when they form in their
ordinary condition by themselves, or by uniting with other waters, a
continued highway over which commerce is or may be carried on with
other States or foreign countries in the customary modes in which
such commerce is conducted by water.
77 U.S. (10 Wall.) 557, 563 (1871). Subsequently, this traditional test
was expanded to include waters that had been used in the past for
interstate commerce, see Economy Light & Power Co. v. United States,
256 U.S. 113, 123 (1921), and waters that are susceptible
[[Page 22263]]
for use with reasonable improvement, see United States v. Appalachian
Elec. Power Co., 311 U.S. 377, 407-10 (1940).
 By the time the 1972 CWA amendments were enacted, the Supreme Court
had held that Congress' authority over the channels of interstate
commerce was not limited to regulation of the channels themselves but
could extend to activities necessary to protect the channels. See
Oklahoma ex rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 523
(1941) (``Congress may exercise its control over the non-navigable
stretches of a river in order to preserve or promote commerce on the
navigable portions.''). The Supreme Court had also clarified that
Congress could regulate waterways that formed a part of a channel of
interstate commerce, even if they are not themselves navigable or do
not cross state boundaries. See Utah v. United States, 403 U.S. 9, 11
(1971).
 These developments were discussed during the legislative process
leading up to the passage of the 1972 CWA amendments, and certain
members referred to the scope of the amendments as encompassing
waterways that serve as a ``link in the chain'' of interstate commerce
as it flows through various channels of transportation, such as
railroads and highways. See, e.g., 118 Cong. Rec. 33756-57 (1972)
(statement of Rep. Dingell); 118 Cong. Rec. 33699 (Oct. 4, 1972)
(statement of Sen. Muskie).\26\ Other references suggest that
congressional committees at least contemplated applying the ``control
requirements'' of the Act ``to the navigable waters, portions thereof,
and their tributaries.'' S. Rep. No. 92-414, at 77 (1971). Some
commenters on this rulemaking stated that Congress' authority under the
CWA is limited to waters that actually transport commerce, not their
tributaries or adjacent wetlands, and that this limitation on CWA
jurisdiction would fully preserve the authority of States to address
pollution. The agencies disagree with these commenters based on the
Supreme Court's holdings and the legislative history of the 1972
amendments discussed above, as well as the text of the 1977 amendments
to the CWA. Specifically, in 1977, when Congress authorized State
assumption over the section 404 dredged or fill material permitting
program, Congress limited the scope of waters that could be assumed by
a State or Tribe by requiring the Corps to retain permitting authority
over RHA waters (as identified by the test outlined in The Daniel Ball)
plus wetlands adjacent to those waters, minus historic-use-only waters.
See 33 U.S.C. 1344(g)(1).\27\ This suggests that Congress had in mind a
broader scope of waters subject to CWA jurisdiction than waters
traditionally understood as navigable. See SWANCC, 531 U.S. at 171;
Riverside Bayview, 474 U.S. at 138 n.11. Thus, Congress intended to
assert federal authority over more than just waters traditionally
understood as navigable, and Congress rooted that authority in ``its
commerce power over navigation.'' SWANCC, 531 U.S. at 168 n.3. However,
there must be a limit to that authority and to what water is subject to
federal jurisdiction. How the agencies should exercise that authority
has been the subject of dispute for decades, but the Supreme Court on
three occasions has analyzed the issue and provided some instructional
guidance for the agencies to consider in developing this final rule.
---------------------------------------------------------------------------
 \26\ The agencies recognize that individual member statements
are not a substitute for full congressional intent, but they do help
provide context for issues that were discussed during the
legislative debates. For a detailed discussion of the legislative
history of the 1972 CWA amendments, see Albrecht & Nickelsburg,
Could SWANCC Be Right? A New Look at the Legislative History of the
Clean Water Act, 32 ELR 11042 (Sept. 2002).
 \27\ For a detailed discussion of the legislative history
supporting the enactment of CWA section 404(g), see Final Report of
the Assumable Waters Subcommittee (May 2017), App. F., available at
https://www.epa.gov/sites/production/files/2017-06/documents/awsubcommitteefinalreprort_05-2017_tag508_05312017_508.pdf https://www.epa.gov/sites/production/files/2017-06/documents/awsubcommitteefinalreprort_05-2017_tag508_05312017_508.pdf.
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2. U.S. Supreme Court Precedent
a. Adjacent Wetlands
 In Riverside Bayview, the Supreme Court considered the Corps'
assertion of jurisdiction over ``low-lying, marshy land'' immediately
abutting a water traditionally understood as navigable on the grounds
that it was an ``adjacent wetland'' within the meaning of the Corps'
then-existing regulations. 474 U.S. at 124. The Court addressed the
question of whether non-navigable wetlands may be regulated as waters
of the United States on the basis that they are ``adjacent to''
navigable-in-fact waters and ``inseparably bound up with'' them because
of their ``significant effects on water quality and the aquatic
ecosystem.'' See id. at 131-35 & n.9.
 In determining whether to give deference to the Corps' assertion of
jurisdiction over adjacent wetlands, the Court acknowledged the
difficulty in determining where federal jurisdiction ends, noting that
the line is somewhere between open water and dry land:
 In 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 (emphasis added). Within this statement, the Supreme Court
identifies a basic principle for adjacent wetlands: The limits of
jurisdiction lie within the ``continuum'' or ``transition'' ``between
open waters and dry land.'' Observing that Congress intended the CWA
``to regulate at least some waters that would not be deemed
`navigable,' '' the Court held that it is ``a permissible
interpretation of the Act'' to conclude that ``a wetland that actually
abuts on a navigable waterway'' falls within the ``definition of
`waters of the United States.' '' Id. at 133, 135. Thus, a wetland that
abuts a water traditionally understood as navigable is subject to CWA
jurisdiction because it is ``inseparably bound up with the `waters' of
the United States.'' Id. at 134. ``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.'' Id.
 The Supreme Court also noted that the agencies can establish
categories of jurisdiction for adjacent wetlands. See id. at 135 n.9.
It made clear that these categories could be reasonable if the Corps
concludes that ``in the majority of cases, adjacent wetlands have
significant effects on water quality and the aquatic ecosystem.'' Id. A
definition of ``waters of the United States'' ``can stand'' even if it
potentially sweeps in individual wetlands that are not sufficiently
``intertwined with the ecosystem of adjacent waterways'' to warrant
protection. Id. In such cases, if the regulating entity determines that
a particular wetland lacks importance to the aquatic environment, or
its importance is outweighed by other factors, that wetland could be
developed through the permit issuance process. Id.
 Some commenters noted that the definition of ``adjacent wetlands''
that the Supreme Court unanimously upheld in Riverside Bayview included
categories of wetlands that would not be per se ``adjacent'' under the
proposed rule, including all ``[w]etlands separated from other waters
of the United States by man-made dikes or barriers, natural river
berms, beach dunes and the like.'' 51 FR 41251 (Nov. 13, 1986). These
commenters stated that the Court deferred to the Corps' judgment that
[[Page 22264]]
wetlands may affect the water quality of jurisdictional waterbodies
even if the waterbodies do not inundate the wetlands. See Riverside
Bayview, 474 U.S. at 133-35. The proposed rule included wetlands as
jurisdictional absent inundation by another water. See e.g., 84 FR 4187
(``The proposed definition of `adjacent wetlands' would not require
surface water exchange between wetlands and the jurisdictional waters
they abut to create the jurisdictional link[.]''). As explained in
Section III.G., the agencies have considered public comments in light
of the statutory text and other relevant considerations and are
finalizing a definition of ``adjacent wetlands'' that is more
encompassing than the proposal. In any event, the agencies note that a
Court's deference to an agency's particular interpretation of a statute
does not foreclose alternative interpretations. The Supreme Court has
held that ``a court's choice of one reasonable reading of an ambiguous
statute does not preclude an implementing agency from later adopting a
different reasonable interpretation.'' United States v. Eurodif S.A.,
555 U.S. 305, 315 (2009). This principle follows from Chevron, U.S.A.,
Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984),
which ``established a `presumption that Congress, when it left
ambiguity in a statute meant for implementation by an agency,
understood that the ambiguity would be resolved, first and foremost, by
the agency, and desired the agency (rather than the courts) to possess
whatever degree of discretion the ambiguity allows.' '' Nat'l Cable &
Telecommunications Ass'n v. Brand X Internet Servs., 545 U.S. 967, 982
(2005) (quoting Smiley v. Citibank, 517 U.S. 735, 740-41 (1996)).
Moreover, an ``initial agency interpretation is not instantly carved in
stone.'' Chevron, 467 U.S. at 863; see also Encino Motorcars, LLC v.
Navarro, 136 S. Ct. 2117, 2125 (2016) (``[A]gencies are free to change
their existing policies as long as they provide a reasoned explanation
for the change.'') (citations omitted). Consistent with the APA and
applicable case law, in this final rule the agencies have provided
ample justification for a change in interpretation of the CWA
concerning the scope of jurisdiction over waters and wetlands,
including any changes from their prior interpretations.
 The Supreme Court in Riverside Bayview declined to decide whether
wetlands that are not adjacent to navigable waters could also be
regulated by the agencies. See 474 U.S. at 124 n.2 and 131 n.8. In
SWANCC a few years later, however, the Supreme Court analyzed a similar
question in the context of an abandoned sand and gravel pit located
some distance from a traditional navigable water, with excavation
trenches that ponded--some only seasonally--and served as habitat for
migratory birds. 531 U.S. at 162-63. The Supreme Court rejected the
government's stated rationale for asserting jurisdiction over such
``nonnavigable, isolated, intrastate waters'' as outside the scope of
CWA jurisdiction. Id. at 171-72. In doing so, the Supreme Court noted
that Riverside Bayview upheld ``jurisdiction over wetlands that
actually abutted on a navigable waterway'' because the wetlands were
``inseparably bound up with the `waters' of the United States.'' Id. at
167.\28\ As summarized by the SWANCC majority:
---------------------------------------------------------------------------
 \28\ At oral argument during Riverside Bayview, the attorney
representing the United States characterized the wetland at issue as
``in fact an adjacent wetland, adjacent--by adjacent, I mean it is
immediately next to, abuts, adjoins, borders, whatever other
adjective you might want to use, navigable waters of the United
States.'' Transcript of Oral Argument at 16, United States v.
Riverside Bayview Homes, 474 U.S. 121 (1985) (No. 84-701).
 It was the significant nexus between the wetlands and
``navigable waters'' that informed our reading of the CWA in
Riverside Bayview Homes. Indeed, we did not ``express any opinion''
on the ``question of authority of the Corps to regulate discharges
of fill material into wetlands that are not adjacent to bodies of
open water . . . .'' In order to rule for [the Corps] here, we would
have to hold that the jurisdiction of the Corps extends to ponds
that are not adjacent to open water. But we conclude that the text
---------------------------------------------------------------------------
of the statute will not allow this.
Id. at 167-68 (internal citations and emphasis omitted).
 The Court also rejected the argument that the use of the abandoned
ponds by migratory birds fell within the power of Congress to regulate
activities that in the aggregate have a substantial effect on
interstate commerce, or that the CWA regulated the use of the ponds as
a municipal landfill because such use was commercial in nature. Id. at
173. Such arguments, the Court noted, raised ``significant
constitutional questions.'' Id. ``Where 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 172-73 (``Congress does not casually authorize
administrative agencies to interpret a statute to push the limit of
congressional authority.''). 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; see also Will v. Michigan Dep't of State Police, 491 U.S. 58,
65 (1989) (``[I]f Congress intends to alter the `usual constitutional
balance between the States and the Federal Government,' it must make
its intention to do so `unmistakably clear in the language of the
statute.' '' (quoting Atascadero State Hospital v. Scanlon, 473 U.S.
234, 242 (1985))); Gregory v. Ashcroft, 501 U.S. 452, 460-61 (1991)
(``[The] plain statement rule . . . acknowledg[es] that the States
retain substantial sovereign powers under our constitutional scheme,
powers with which Congress does not readily interfere.''). ``Rather
than expressing a desire to readjust the federal-state balance in this
manner, Congress chose [in the CWA] to `recognize, preserve, and
protect the primary responsibilities and rights of States . . . to plan
the development and use . . . of land and water resources . . . .''
SWANCC, 531 U.S. at 174 (quoting 33 U.S.C. 1251(b)). The Court found no
clear statement from Congress that it had intended to permit federal
encroachment on traditional State power and construed the CWA to avoid
the significant constitutional questions related to the scope of
federal authority authorized therein. Id.\29\
---------------------------------------------------------------------------
 \29\ The agencies note that during oral argument in SWANCC,
Justice Kennedy stated, ``[T]his case, it seems to me, does point up
the problem that petitioner's counsel raised quoting from page 1 of
the blue brief, `it is the primary responsibility of the states to
eliminate pollution and to plan development and use of land' . . . .
It seems to me that this illustrates that the way in which the Corps
has promulgated its regulation departs from the design of the
statute.'' Transcript of Oral Argument at 40, Solid Waste Agency of
Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159
(2001) (No. 99-1178) (emphasis added). And several years later,
during oral argument in Rapanos, after the U.S. Solicitor General
stated, ``[W]hat Congress recognized in 1972 is that they had to
regulate beyond traditional navigable waters,'' Justice Kennedy
stated, ``But the Congress in 1972 also . . . said it's a statement
of policy to reserve to the States the power and the responsibility
to plan land use and water resources. And under your definition, I
just see that we're giving no scope at all to that clear statement
of the congressional policy.'' Transcript of Oral Argument at 58,
Rapanos v. United States and Carabell v. United States, 547 U.S. 715
(2006) (Nos. 04-1034, 04-1384). Although the agencies do not give
independent weight to these statements at oral argument, the
statements are consistent with the agencies' interpretation of the
CWA and applicable Supreme Court decisions.
---------------------------------------------------------------------------
 Historically, the Federal government has interpreted and applied
the SWANCC decision more narrowly, focusing on the specific holding in
the case as rejecting federal jurisdiction over the isolated ponds and
mudflats at issue in that case based on their use by migratory birds.
By contrast, members of the regulated community, certain States and
other interested stakeholders have
[[Page 22265]]
argued that SWANCC stands for a broader proposition based on key
federalism and separation of powers principles.\30\ In the preamble to
the proposed rule, the agencies solicited comment as to the proper
scope and interpretation of SWANCC. 84 FR 4165. Some commenters argued
that the SWANCC decision should be interpreted narrowly to apply only
to the facts presented in that case; other commenters argued that the
agencies should apply the reasoning of the SWANCC decision broadly, in
a manner similar to how the agencies had previously interpreted the
reasoning of Justice Kennedy's concurring opinion in Rapanos to extend
beyond wetlands to tributaries and other waters, for example. The
agencies agree with commenters that the interpretation and
implementation of these Supreme Court decisions within agency
regulatory programs should be consistent, and that the reasoning in the
SWANCC decision stands for key principles related to federalism and the
balancing of the traditional power of States to regulate land and water
resources within their borders with the need for national water quality
regulation.
---------------------------------------------------------------------------
 \30\ The agencies also recognize that Justice Stevens, writing
for himself and three other Justices in dissent in SWANCC,
interpreted the SWANCC majority opinion to apply beyond the
Migratory Bird Rule and the specific ponds at issue in SWANCC. His
dissent stated that the decision ``invalidates the 1986 migratory
bird regulation as well as the Corps' assertion of jurisdiction over
all waters except for actually navigable waters, their tributaries,
and wetlands adjacent to each.'' 531 U.S. at 176-77 (Stevens, J.,
dissenting) (emphasis added).
---------------------------------------------------------------------------
 The agencies recently repealed the 2015 Rule and explained in the
preamble of that action that the 2015 Rule had improperly allowed for
the application of the significant nexus standard in a manner that
would result in the assertion of jurisdiction over waters that the
Court deemed non-jurisdictional in SWANCC. 84 FR 56626-27. By allowing
federal jurisdiction to reach certain isolated ponds, such as those at
issue in SWANCC, and certain physically remote wetlands that ``do not
implicate the boundary-drawing problem of Riverside Bayview,'' the
agencies concluded that the 2015 Rule asserted federal control over
some features that ``lack the necessary connection to covered waters .
. . described as a `significant nexus' in SWANCC[.]'' Rapanos, 547 U.S.
at 742 (Scalia, J., plurality); see also Hawkes, 136 S. Ct. at 1817
(Kennedy, J., concurring in the judgment) (``[T]he reach and systemic
consequences of the Clean Water Act remain a cause for concern.''
(emphasis added)). This final rule, in contrast to the 2015 Rule,
avoids pressing against the outer limits of the agencies' authority
under the Commerce Clause and Supreme Court case law and recognizes the
limiting principles articulated by the SWANCC decision. This final rule
would not allow for the exercise of jurisdiction over waters similar to
those at issue in SWANCC.
 Several years after SWANCC, the Supreme Court considered the
concept of adjacency in consolidated cases arising out of the Sixth
Circuit. See Rapanos v. United States, 547 U.S. 715 (2006). In one
case, the Corps had determined that wetlands on three separate sites
were subject to CWA jurisdiction because they were adjacent to ditches
or man-made drains that eventually connected to traditional navigable
waters several miles away through other ditches, drains, creeks, and
rivers. Id. at 719-20, 729. In another case, the Corps had asserted
jurisdiction over a wetland separated from a man-made drainage ditch by
a four-foot-wide man-made berm. Id. at 730. The ditch emptied into
another ditch, which then connected to a creek, and eventually
connected to Lake St. Clair,\31\ a traditional navigable water,
approximately a mile from the parcel at issue. The berm was largely or
entirely impermeable but may have permitted occasional overflow from
the wetland to the ditch. Id. The Court, in a fractured opinion,
vacated and remanded the Sixth Circuit's decision upholding the Corps'
asserted jurisdiction over the four wetlands at issue, with Justice
Scalia writing for the plurality and Justice Kennedy concurring in the
judgment but on alternative grounds. Id. at 757 (Scalia, J.,
plurality); id. at 787 (Kennedy, J., concurring in the judgment).
---------------------------------------------------------------------------
 \31\ Lake St. Clair is a Rivers and Harbors Act section 10
water. See p. 7: https://www.lre.usace.army.mil/Portals/69/docs/regulatory/PDFs/GENSEC10.pdf. It is also described in Justice
Kennedy's opinion in Rapanos as ``a 430-square mile lake located
between Michigan and Canada that is popular with boating and fishing
and produces some 48 percent of the sport fish caught in the Great
Lakes[.]'' Rapanos, 547 U.S. at 764 (Kennedy, J., concurring in the
judgment).
---------------------------------------------------------------------------
 The plurality determined that CWA jurisdiction extended to only
adjacent ``wetlands with a continuous surface connection to bodies that
are `waters of the United States' in their own right, so that there is
no clear demarcation between `waters' and wetlands.'' Rapanos, 547 U.S.
at 742 (Scalia, J., plurality). The plurality then concluded that
``establishing . . . wetlands . . . covered by the Act requires two
findings: First, that the adjacent channel contains a `wate[r] of the
United States,' (i.e., a relatively permanent body of water connected
to traditional interstate navigable waters); and second, that the
wetland has a continuous surface connection with that water, making it
difficult to determine where the `water' ends and the `wetland'
begins.'' Id. (alteration in original).
 In reaching the adjacency component of the two-part analysis, the
plurality interpreted Riverside Bayview and the Court's subsequent
SWANCC decision characterizing Riverside Bayview as authorizing
jurisdiction over wetlands that physically abutted traditional
navigable waters. Id. at 740-42. The plurality focused on the
``inherent ambiguity'' described in Riverside Bayview in determining
where on the continuum between open waters and dry land the scope of
federal jurisdiction should end. Id. at 740. It was ``the inherent
difficulties of defining precise bounds to regulable waters,'' id. at
741 n.10, according to the plurality, that prompted the Court in
Riverside Bayview to defer to the Corps' inclusion of adjacent wetlands
as ``waters'' subject to CWA jurisdiction based on proximity. Id. at
741 (``When we characterized the holding of Riverside Bayview in
SWANCC, we referred to the close connection between waters and the
wetlands they gradually blend into: `It was the significant nexus
between the wetlands and `navigable waters' that informed our reading
of the CWA in Riverside Bayview Homes.' ''); see also Riverside
Bayview, 474 U.S. at 134 (``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.'' (quoting 42 FR 37128 (July 19, 1977))). The plurality
also noted that ``SWANCC rejected the notion that the ecological
considerations upon which the Corps relied in Riverside Bayview . . .
provided an independent basis for including entities like `wetlands'
(or `ephemeral streams') within the phrase `the waters of the United
States.' SWANCC found such ecological considerations irrelevant to the
question whether physically isolated waters come within the Corps'
jurisdiction.'' Rapanos, 547 U.S. at 741-42 (emphasis in original).
 Justice Kennedy disagreed with the plurality's conclusion that
adjacency requires a ``continuous surface connection'' to covered
waters. Id. at 772 (Kennedy, J., concurring in the judgment). In
reading the phrase ``continuous surface connection'' to mean a
continuous ``surface-water connection,'' id. at 776 (emphasis
[[Page 22266]]
added), and interpreting the plurality's standard to include a
``surface-water-connection requirement,'' id. at 774 (emphasis added),
Justice Kennedy stated that ``when a surface-water connection is
lacking, the plurality forecloses jurisdiction over wetlands that abut
navigable-in-fact waters--even though such navigable waters were
traditionally subject to federal authority.'' Id. at 776. He noted that
the Riverside Bayview Court ``deemed it irrelevant whether `the
moisture creating the wetlands . . . find[s] its source in the adjacent
bodies of water.'' Id. at 772 (internal citations omitted); see also
Riverside Bayview, 474 U.S. at 134 (``[A]djacent wetlands may be
defined as waters under the Act. 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 plurality did not directly address the precise distinction
raised by Justice Kennedy regarding his interpretation of the
plurality's ``continuous surface connection'' requirement to mean a
continuous ``surface-water connection.'' The plurality did note in
response, however, that the ``Riverside Bayview opinion required'' a
``continuous physical connection,'' Rapanos, 547 U.S. at 751 n.13
(Scalia, J., plurality) (emphasis added), and focused on evaluating
adjacency between a ``water'' and a wetland ``in the sense of
possessing a continuous surface connection that creates the boundary-
drawing problem we addressed in Riverside Bayview.'' Id. at 757. The
plurality also noted that its standard includes a ``physical-connection
requirement,'' not hydrological, between wetlands and covered waters.
Id. at 751 n.13 (emphasis added). In other words, the plurality
appeared to be more focused on the abutting nature rather than the
source of water creating the wetlands at issue in Riverside Bayview to
describe the legal constructs applicable to adjacent wetlands. See id.
at 747; see also Webster's II, New Riverside University Dictionary
(1994) (defining ``abut'' to mean ``to border on'' or ``to touch at one
end or side of something''). The plurality agreed with Justice Kennedy
and the Riverside Bayview Court that ``[a]s long as the wetland is
`adjacent' to covered waters . . . its creation vel non by inundation
is irrelevant.'' Rapanos, 547 U.S. at 751 n.13 (Scalia, J.,
plurality).\32\
---------------------------------------------------------------------------
 \32\ In the Rapanos Guidance, the agencies interpreted the
plurality's ``continuous surface connection'' as not requiring a
continuous surface water connection. See, e.g., Rapanos Guidance at
7 n.28 (``A continuous surface connection does not require surface
water to be continuously present between the wetland and the
tributary.''). The agencies continue to endorse that interpretation.
In Rapanos, both Justice Scalia and Justice Kennedy recognized that
a wetland can be adjacent to a jurisdictional water absent
inundation from that water.
---------------------------------------------------------------------------
 Because wetlands with a physically remote hydrologic connection do
not raise the same boundary-drawing concerns presented by actually
abutting wetlands, the plurality determined that the ``inherent
ambiguity in defining where water ends and abutting (`adjacent')
wetlands begin'' upon which Riverside Bayview rests does not apply to
such features. Id. at 742 (``Wetlands with only an intermittent,
physically remote hydrologic connection to `waters of the United
States' do not implicate the boundary-drawing problem of Riverside
Bayview, and thus lack the necessary connection to covered waters that
we described as a `significant nexus' in SWANCC[.]''). The plurality
supported this position by referring to the Court's treatment of
certain isolated waters in SWANCC as non-jurisdictional. Rapanos, 547
U.S. at 741-42; see also id. at 726 (``We held that `nonnavigable,
isolated, intrastate waters--which, unlike the wetlands at issue in
Riverside Bayview, did not `actually abu[t] on a navigable waterway,'--
were not included as `waters of the United States.' '') (internal
citations omitted). It interpreted the reasoning of SWANCC to exclude
isolated waters. The plurality also found ``no support for the
inclusion of physically unconnected wetlands as covered `waters' ''
based on Riverside Bayview's treatment of the Corps' definition of
adjacent. Id. at 747; see also id. at 746 (``[T]he Corps' definition of
`adjacent' . . . has been extended beyond reason . . . .'').
 Although ultimately concurring in the judgment, Justice Kennedy
focused on the ``significant nexus'' between adjacent wetlands and
traditional navigable waters as the basis for determining whether a
wetland is a water subject to CWA jurisdiction. He quotes the SWANCC
decision, which explains that ``[i]t was the significant nexus between
the wetlands and `navigable waters' that informed our reading of the
[Act] in Riverside Bayview Homes.'' SWANCC, 531 U.S. at 167. But
Justice Kennedy also interpreted the reasoning of SWANCC to exclude
certain isolated waters. His opinion notes that: ``Because such a nexus
[in that case] was lacking with respect to isolated ponds, the Court
held that the plain text of the statute did not permit the Corps'
action.'' Rapanos, 547 U.S. at 767 (Kennedy, J., concurring in the
judgment) (internal citation omitted). It further states that the
wetlands at issue in Riverside Bayview were ``adjacent to [a]
navigable-in-fact waterway[ ]'' while the ``ponds and mudflats''
considered in SWANCC ``were isolated in the sense of being unconnected
to other waters covered by the Act.'' Id. at 765-66. ``Taken together,
these cases establish that in some instances, as exemplified by
Riverside Bayview, 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. In other instances, as exemplified by SWANCC, there may be
little or no connection. Absent a significant nexus, jurisdiction under
the Act is lacking.'' Id. at 767.
 According to Justice Kennedy, whereas the isolated ponds and
mudflats in SWANCC lacked a ``significant nexus'' to navigable waters,
it is the ``conclusive standard for jurisdiction'' based on ``a
reasonable inference of ecological interconnection'' between adjacent
wetlands and navigable-in-fact waters that allows for their categorical
inclusion as ``waters of the United States.'' Rapanos, 547 U.S. at 780
(``[T]he assertion of jurisdiction for those wetlands [adjacent to
navigable-in-fact waters] is sustainable under the Act by showing
adjacency alone.''). Justice Kennedy surmised that it may be that the
same rationale ``without any inquiry beyond adjacency . . . could apply
equally to wetlands adjacent to certain major tributaries.'' Id. He
noted that the Corps could establish by regulation categories of
tributaries based on volume of flow, proximity to navigable waters, or
other relevant factors that ``are significant enough that wetlands
adjacent to them are likely, in the majority of cases, to perform
important functions for an aquatic system incorporating navigable
waters.'' Id. at 780-81. However, ``[t]he Corps' existing standard for
tributaries'' provided Justice Kennedy ``no such assurance'' to infer
the categorical existence of a requisite nexus between waters
traditionally understood as navigable and wetlands adjacent to
nonnavigable tributaries. Id. at 781. That is because:
 [T]he breadth of the [tributary] standard--which seems to leave
wide room for regulation of drains, ditches, and streams remote from
any navigable-in-fact water and carrying only minor water volumes
towards it--precludes its adoption as the determinative measure of
whether adjacent wetlands are likely to play an important role in
the integrity of an aquatic system comprising navigable waters as
traditionally understood. Indeed, in many cases, wetlands
[[Page 22267]]
adjacent to tributaries covered by this standard might appear little
more related to navigable-in-fact waters than were the isolated
ponds held to fall beyond the Act's scope in SWANCC.
Rapanos, 547 U.S. at 781-82.
 To avoid this outcome, Justice Kennedy stated that, absent
development of a more specific regulation and categorical inclusion of
wetlands adjacent to ``certain major'' or even ``minor'' tributaries as
was established in Riverside Bayview, id. at 780-81, the Corps ``must
establish a significant nexus on a case-by-case basis when it seeks to
regulate wetlands based on adjacency to nonnavigable tributaries. Given
the potential overbreadth of the Corps' regulations, this showing is
necessary to avoid unreasonable applications of the statute.'' Id. at
782. Justice Kennedy stated that adjacent ``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 780. ``Where an adequate nexus is
established for a particular wetland, it may be permissible, as a
matter of administrative convenience or necessity, to presume covered
status for other comparable wetlands in the region.'' Id. at 782. In
establishing this significant nexus test, Justice Kennedy relied, in
part, on the overall objective of the CWA to ``restore and maintain the
chemical, physical and biological integrity of the Nation's waters.''
Id. at 779 (quoting 33 U.S.C. 1251(a)). However, Justice Kennedy also
acknowledged that ``environmental concerns provide no reason to
disregard limits in the statutory text.'' Id. at 778. With respect to
wetlands adjacent to nonnavigable tributaries, Justice Kennedy
therefore determined that ``mere adjacency . . . is insufficient[.] A
more specific inquiry, based on the significant-nexus standard, is . .
. necessary.'' Id. at 786. Justice Kennedy noted that under the Corps'
interpretation at issue in the case, which did not require adjacent
wetlands to possess a significant nexus with navigable waters, federal
regulation would be permitted ``whenever wetlands lie alongside a ditch
or drain, however remote or insubstantial, that eventually may flow
into traditional navigable waters. The deference owed to the Corps'
interpretation of the statute does not extend so far.'' Id. at 778-79.
 Since the Rapanos decision, the Federal government has adopted a
broad interpretation of Justice Kennedy's concurring opinion, arguing
that his ``significant nexus'' test provides an independent basis for
establishing jurisdiction over certain waters of the United States. And
rather than limiting the application of Justice Kennedy's opinion to
the specific facts and wetlands at issue in that case, similar to their
treatment of the SWANCC decision, the agencies previously have applied
Justice Kennedy's reasoning more broadly to include, for example, the
application of the significant nexus test to determining jurisdiction
over tributaries, not just wetlands. Many courts have deferred to this
position, and some courts rely exclusively on Justice Kennedy's
significant nexus test while other courts have held that jurisdiction
can be established under either the plurality or concurring opinions.
The agencies' final rule, as explained in Section III, is informed in
several key aspects by Justice Kennedy's opinion, but the agencies now
appropriately recognize some of the limiting principles articulated
within his concurring opinion. The agencies also recognize that the
reasoning in SWANCC contains more instruction than the agencies have
historically acknowledged.
 In summary, although the standards that the Rapanos plurality and
Justice Kennedy established are not identical, and each standard
excludes some waters and wetlands that the other standard does not, the
standards contain substantial similarities. The plurality and Justice
Kennedy agreed in principle that the determination must be made using a
basic two-step approach that considers (1) the connection of the
wetland to the tributary; and (2) the status of the tributary with
respect to downstream traditional navigable waters. The plurality and
Justice Kennedy also agreed that the connection between the wetland and
the tributary must be close. The plurality referred to that connection
as a ``continuous surface connection'' or ``continuous physical
connection,'' as demonstrated in Riverside Bayview. Id. at 742, 751
n.13. Justice Kennedy recognized 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.'' Id. at 767. The second part of their
common analytical framework is addressed in the next section.
b. Tributaries
 As some commenters noted, the definition of ``tributary'' was not
addressed in either Riverside Bayview or SWANCC, nor were tributaries
the waters at issue in Rapanos. Yet while the focus of Rapanos was on
whether the Corps could regulate wetlands adjacent to nonnavigable
tributaries far removed from navigable-in-fact waters, the plurality
and concurring opinions provide some guidance as to the scope of CWA
coverage of tributaries to waters more traditionally understood as
navigable.
 The plurality and Justice Kennedy both recognized the
jurisdictional scope of the CWA is not restricted to traditional
navigable waters. Rapanos, 547 U.S. at 731 (Scalia, J., plurality)
(``[T]he Act's term `navigable waters' includes something more than
traditional navigable waters.''); id. at 767 (Kennedy, J., concurring
in the judgment) (``Congress intended to regulate at least some waters
that are not navigable in the traditional sense.''). Both also agreed
that federal authority under the Act has limits. See id. at 731-32
(Scalia, J., plurality) (`` `[T]he waters of the United States' . . .
cannot bear the expansive meaning that the Corps would give it.''); id.
at 778-79 (Kennedy, J., concurring in the judgment) (``The deference
owed to the Corps' interpretation of the statute does not extend'' to
``wetlands'' which ``lie alongside a ditch or drain, however remote or
insubstantial, that eventually may flow into traditional navigable
waters.'').
 With respect to tributaries specifically, both the plurality and
Justice Kennedy focused in part on a tributary's contribution of flow
to and connection with traditional navigable waters. The plurality
would include as ``waters of the United States'' ``only relatively
permanent, standing or flowing bodies of water'' and would define such
``waters'' as including streams, rivers, oceans, lakes and other bodies
of waters that form geographical features, noting that all such ``terms
connote continuously present, fixed bodies of water.'' Rapanos, 547
U.S. at 732-33, 739 (Scalia, J., plurality). The plurality would have
also required relatively permanent waters to be connected to
traditional navigable waters in order to be jurisdictional. See id. 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'') (emphasis added). The plurality would also have
excluded ephemeral flows and related features, stating ``[n]one of
these terms encompasses transitory puddles or ephemeral flows of
water.'' Id. at 733; see also id. at 734 (``In applying the definition
to `ephemeral streams,' . . .
[[Page 22268]]
the Corps has stretched the term `waters of the United States' beyond
parody. The plain language of the statute simply does not authorize
this `Land Is Waters' approach to federal jurisdiction.''). Justice
Kennedy likely would exclude some streams considered jurisdictional
under the plurality's opinion, but he may include some that would be
excluded by the plurality. See id. at 769 (Kennedy, J., concurring in
the judgment) (noting that under the plurality's test, ``[t]he merest
trickle, if continuous, would count as a `water' subject to federal
regulation, while torrents thundering at irregular intervals through
otherwise dry channels would not'').
 Both the plurality and Justice Kennedy would have included some
seasonal or intermittent streams as waters of the United States.
Rapanos, 547 U.S. at 732 n.5, 733 (Scalia, J., plurality); id. at 769
(Kennedy, J., concurring in the judgment). The plurality noted, for
example, 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).
Neither the plurality nor Justice Kennedy, however, defined with
precision where to draw the line. See, e.g., id. (Scalia, J.,
plurality) (``[W]e have no occasion in this litigation to decide
exactly when the drying-up of a stream bed is continuous and frequent
enough to disqualify the channel as a `wate[r] of the United States.'
It suffices for present purposes that channels containing permanent
flow are plainly within the definition, and that . . . streams whose
flow is `[c]oming and going at intervals . . . [b]roken, fitful,' . . .
or `existing only, or no longer than, a day; diurnal . . . short-
lived,' . . . are not.'') (internal citations omitted). The plurality
provided, however, that ``navigable waters'' must have ``at a bare
minimum, the ordinary presence of water,'' id. at 734, and Justice
Kennedy noted that the Corps can identify by regulation categories of
tributaries based on ``their volume of flow (either annually or on
average), their proximity to navigable waters, or other relevant
considerations'' that ``are significant enough that wetlands adjacent
to them are likely, in the majority of cases, to perform important
functions for an aquatic system incorporating navigable waters,'' id.
at 780-81 (Kennedy, J., concurring in the judgment).
 Both the plurality and Justice Kennedy also agreed that the Corps'
existing treatment of tributaries raised significant jurisdictional
concerns. For example, the plurality was concerned about the Corps'
broad interpretation of tributaries. See Rapanos, 547 U.S. at 738
(Scalia, J., plurality) (``Even if the term `the waters of the United
States' were ambiguous as applied to channels that sometimes host
ephemeral flows of water (which it is not), we would expect a clearer
statement from Congress to authorize an agency theory of jurisdiction
that presses the envelope of constitutional validity.''). And Justice
Kennedy objected to the categorical assertion of jurisdiction over
wetlands adjacent to waters deemed tributaries under the Corps' then-
existing standard, ``which seems to leave wide room for regulation of
drains, ditches, and streams remote from any navigable-in-fact water
and carrying only minor water volumes towards it.'' Id. at 781
(Kennedy, J., concurring in the judgment); see also id. at 781-82
(``[I]n many cases wetlands adjacent to tributaries covered by this
standard might appear little more related to navigable-in-fact waters
than were the isolated ponds held to fall beyond the Act's scope in
SWANCC.'').
 Beyond tributaries, the plurality and Justice Kennedy also offered
some insight regarding CWA jurisdiction with respect to other
relatively permanent bodies of water, such as lakes and ponds, and
their connection to traditional navigable waters. The plurality
describes a ``water of the United States'' as ``a relatively permanent
body of water connected to traditional interstate navigable waters[.]''
Id. at 742 (emphasis added). The plurality did not specify, however,
what would constitute a sufficient connection between such relatively
permanent waters and downstream traditional navigable waters. When
considered in the context of Justice Scalia's entire opinion, the
plurality signaled concern that certain types of connections are likely
insufficient to maintain jurisdiction; for instance, by characterizing
an ``expansive definition of `tributaries' '' as one that includes
``dry arroyos connected to remote waters through the flow of
groundwater over `centuries,' '' id. at 725-26 (internal citations
omitted), and describing potential federal control over ``irrigation
ditches and drains that intermittently connect to covered waters'' as
``sweeping.'' Id. at 726-27. In addition to ``tributaries,'' the
plurality noted that the Corps and lower courts have ``define[d]
`adjacent' wetlands broadly'' to include wetlands ``hydrologically
connected'' ``to covered waters'' ``through directional sheet flow
during storm events,'' and wetlands ``connected to the navigable water
by flooding, on average, once every 100 years[.]'' Rapanos, 547 U.S. at
728 (internal quotations and citations omitted). Justice Kennedy noted
that ``in some instances, as exemplified by Riverside Bayview, the
connection between a nonnavigable water . . . and a navigable water may
be so close, or potentially so close, that the Corps may deem the water
. . . a `navigable water' under the Act. In other instances, as
exemplified by SWANCC, there may be little or no connection.'' Id. at.
767 (Kennedy, J., concurring in the judgment). Justice Kennedy also
stated that ``mere hydrologic connection should not suffice in all
cases; the connection may be too insubstantial for the hydrologic
linkage to establish the required nexus with navigable waters as
traditionally understood.'' Id. at 784-85.
 Some commenters agreed that aspects of the plurality's and Justice
Kennedy's opinions share similarities regarding the limits of federal
jurisdiction under the CWA, while other commenters disagreed that the
opinions share important commonalities. These commenters asserted that
the opinions have disparate rationales that cannot be reconciled. While
the agencies acknowledge that the plurality and Justice Kennedy viewed
the question of federal CWA jurisdiction differently, as discussed
above, the agencies find that there are sufficient commonalities
between these opinions to help instruct the agencies on where to draw
the line between Federal and State waters.
3. Principles and Considerations
 As discussed in the previous sections, a few important principles
emerge that can serve as the basis for the agencies' final regulatory
definition. As a threshold matter, the power conferred on the agencies
under the CWA to regulate the waters of the United States is grounded
in Congress' commerce power over navigation. The agencies can choose to
regulate beyond waters more traditionally understood as navigable,
including some tributaries and relatively permanent bodies of water
connected to those traditional navigable waters, but the agencies must
provide a reasonable basis grounded in the language and structure of
the Act for determining the extent of jurisdiction. The agencies can
also choose to regulate wetlands adjacent to covered waters beyond
those traditionally understood as navigable, if the wetlands are
closely connected to those waters, such as in the transitional zone
between open waters and dry land. The Supreme
[[Page 22269]]
Court's opinion in SWANCC, however, calls into question the agencies'
authority to regulate nonnavigable, isolated, intrastate waters that
lack a sufficient connection to traditional navigable waters. The
decision counsels that the agencies should avoid regulatory
interpretations of the CWA that raise constitutional questions
regarding the scope of their statutory authority. Finally, the agencies
can regulate certain waters by category, which could improve regulatory
predictability and certainty and ease administrative burdens while
still effectuating the purposes of the Act.
 In developing an appropriate regulatory framework for the final
rule, the agencies recognize and respect the primary responsibilities
and rights of States to regulate their land and water resources as
reflected in CWA section 101(b). 33 U.S.C. 1251(b), see also id. at
1370. The oft-quoted objective of the CWA to ``restore and maintain the
chemical, physical, and biological integrity of the Nation's waters,''
id. at 1251(a), must be implemented in a manner consistent with
Congress' policy directives to the agencies. The Supreme Court long ago
recognized the distinction between federal waters traditionally
understood as navigable and waters ``subject to the control of the
States.'' The Daniel Ball, 77 U.S. (10 Wall.) 557, 564-65 (1870). Over
a century later, the Supreme Court in SWANCC reaffirmed the State's
``traditional and primary power over land and water use.'' SWANCC, 531
U.S. at 174; accord Rapanos, 547 U.S. at 738 (Scalia, J., plurality).
While CWA 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. This final rule recognizes and preserves the autonomy
of Tribes just as it recognizes and preserves the authority of States.
 Ensuring that States and Tribes retain authority over their land
and water resources, reflecting the policy in section 101(b), helps
carry out the overall objective of the CWA and ensures that the
agencies are giving full effect and consideration to the entire
structure and function of the Act. See, e.g., Rapanos, 547 U.S. at 755-
56 (Scalia, J., plurality) (``[C]lean water is not the only purpose of
the statute. So is the preservation of primary state responsibility for
ordinary land-use decisions. 33 U.S.C. 1251(b).'') (emphasis in
original). That includes the dozens of non-regulatory grant, research,
nonpoint source, groundwater, and watershed planning programs that were
intended by Congress to assist the States in controlling pollution in
the nation's waters, not just its navigable waters. These non-
regulatory sections of the CWA reveal Congress' intent to restore and
maintain the integrity of the nation's waters using federal assistance
to support State, tribal, and local partnerships to control pollution
of the nation's waters in addition to a federal regulatory prohibition
on the discharge of pollutants to its navigable waters. See e.g., id.
at 745 (``It is not clear that the state and local conservation efforts
that the CWA explicitly calls for, see 33 U.S.C. 1251(b), are in any
way inadequate for the goal of preservation.''). Regulating all of the
nation's waters using the Act's federal regulatory mechanisms would
call into question the need for the more holistic planning provisions
of the Act and the State partnerships they entail. Therefore, by
recognizing the distinctions between the nation's waters and its
navigable waters and between the overall objective and goals of the CWA
and the specific policy directives from Congress, the agencies can
fully implement the entire structure of the Act while respecting the
specific word choices of Congress. See, e.g., Bailey, 516 U.S. at 146;
Nat'l Fed'n of Indep. Bus., 567 U.S. at 544.
 Some commenters agreed with the interpretation that the CWA
establishes a comprehensive scheme to achieve the Act's objective
through a combination of non-regulatory programs and grants for all of
the nation's waters, and a more targeted federal permitting program for
discharges of pollutants to the subset of the nation's waters
identified as waters of the United States. Other commenters expressed
concern that the proposed rule would not further the CWA's objective to
``restore and maintain the chemical, physical, and biological integrity
of the Nation's waters,'' 33 U.S.C. 1251(a), because fewer waters would
be jurisdictional under the proposal than were regulated under the 2015
Rule or the pre-2015 regulatory regime. The agencies disagree with
these commenters. The agencies are mindful that ``no legislation
pursues its purposes at all costs,'' Rodriguez v. United States, 480
U.S. 522, 525-26 (1987), including the CWA. The CWA's objective must be
balanced with the policy of Congress to preserve the primary State
responsibility for ordinary land-use decisions. The purpose of this
rulemaking is to establish the boundary between regulated ``waters of
the United States'' and the waters subject solely to State and tribal
authority. 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.
 Some commenters agreed with the statements in the preamble to the
proposed rule that the CWA preserves a significant and primary role for
the States in implementing various aspects of the CWA, reflecting an
intent to balance the States' traditional powers to regulate land and
water resources within their borders with the need for national water
quality regulation. Other commenters stated that section 101(b) is
primarily concerned with State implementation of water pollution
control measures, not the jurisdictional reach of the Act, and that a
lawful and protective definition of jurisdictional waters under the Act
does not disturb or undermine the States' exercise of primary
authority. Rather, they expressed concern that the rule would harm the
States in exercising their authority as envisioned by section 101(b)
by, for example, increasing the financial and administrative burden on
States to protect their waters.
 The agencies interpret the policy of Congress, set forth in section
101(b), as relevant to all aspects of the implementation of the CWA,
both implementing federally-established standards as well as the scope
of waters subject to such standards and regulatory programs. When
promulgating the 2015 Rule, the agencies endorsed a narrower view of
Congress' policy in section 101(b) as limited to implementation of the
Act's regulatory programs by States and State authority to impose
conditions on ``waters of the United States'' that are more stringent
than the conditions that the agencies impose under the Act. In the
final Step One Rule, the agencies concluded that such a view was
improperly narrow and failed to place sufficient weight on the policy
of Congress in section 101(b). See 84 FR 56654. Having considered the
public comments submitted in this rulemaking, the agencies remain of
the view that nothing in section 101(b) suggests that it is limited to
implementing federal regulatory programs or imposing conditions on
[[Page 22270]]
``waters of the United States'' that are more stringent than the
conditions that the agencies impose under the Act. Indeed, the
overarching policy statement of 101(b) ``to recognize, preserve, and
protect the primary responsibilities and rights of States to prevent,
reduce, and eliminate pollution, to plan the development and use . . .
of land and water resources,'' was included in the Act in 1972; the
additional 101(b) policy statement ``that the States . . . implement
the permit programs under sections 402 and 404 of this Act'' was not
added until the 1977 amendments. 91 Stat. 1567, 1575 Public Law 95-217
(1977); see also Rapanos, 547 U.S. at 737 (Scalia, J., plurality)
(``Thus, the policy [to recognize, preserve, and protect the primary
responsibilities and rights of States to prevent, reduce, and eliminate
pollution, to plan the development and use . . . of land and water
resources] plainly referred to something beyond the subsequently added
state administration program of 33 U.S.C. 1344(g)-(l).'') (citations
omitted). The agencies acknowledge that States without comprehensive
pre-existing programs that seek to regulate waters no longer
jurisdictional under this final rule may incur new costs and
administrative burdens, and they discuss those costs in the Economic
Analysis for the final rule. Such obligations are inherent in the
exercise of the States' authority that Congress embedded in the CWA.
States are free to evaluate the most effective means of addressing
their waters and may weigh the costs and benefits of doing so.
 The agencies also heard from Tribes that because the agencies
generally implement CWA programs on tribal lands, the proposed rule
would affect Tribes differently than it would affect most States. Some
Tribes have received Treatment as a State status to administer CWA
programs, and other Tribes have established tribal water programs under
tribal law or have the authority to establish such tribal water
programs. Other Tribes may currently lack the capacity to create a
tribal water program, to administer a program, or to expand programs
that currently exist, and may rely on the Federal government for
enforcement of water quality violations. See Chapter III of the
Resource and Programmatic Assessment (RPA) for the final rule. The
final rule preserves tribal authority to choose whether or not to
regulate waters that are not covered under the CWA.
 The agencies are also cognizant that the ``Clean Water Act imposes
substantial criminal and civil penalties for discharging any pollutant
into waters covered by the Act without a permit.'' Hawkes, 136 S. Ct.
at 1812; see also Sackett, 132 S. Ct. at 1374-75 (Alito, J.,
concurring) (``[T]he combination of the uncertain reach of the Clean
Water Act and the draconian penalties imposed for the sort of
violations alleged in this case still leaves most property owners with
little practical alternative but to dance to the EPA's tune.''). As the
Chief Justice observed in Hawkes, ``[i]t is often difficult to
determine whether a particular piece of property contains waters of the
United States, but there are important consequences if it does.'' 136
S. Ct. at 1812; see also id. at 1816-17 (Kennedy, J., concurring in the
judgment) (stating that ``the reach and systemic consequences of the
Clean Water Act remain a cause for concern'' and ``continue[] to raise
troubling questions regarding the Government's power to cast doubt on
the full use and enjoyment of private property throughout the
Nation''). Given the significant civil and criminal penalties
associated with the CWA, the agencies seek to promote regulatory
certainty and to provide fair and predictable notice of the limits of
federal jurisdiction. A number of commenters expressed support for the
emphasis on the importance of fair notice in the proposed rule and
cited in support Justice Gorsuch's concurring opinion in Sessions v.
Dimaya, 138 S. Ct. 1204, 1223-25 (2018) (characterizing fair notice as
possibly the most fundamental of the customary protections provided by
the Constitution's guarantee of due process, and stating that vague
laws are an exercise of ``arbitrary power . . . leaving the people in
the dark about what the law demands and allowing prosecutors and courts
to make it up'').
 The agencies interpret their authority to include promulgation of a
new regulatory definition of ``waters of the United States,'' as
directed by Executive Order 13778, so long as the new definition is
authorized under the law and based on a reasoned explanation. FCC v.
Fox Television Stations, Inc., 556 U.S. 502, 515 (2009) (``Fox''). A
revised rulemaking based on a change in interpretation of statutory
authorities is well within federal agencies' discretion. Nat'l Ass'n of
Home Builders v. EPA, 682 F.3d 1032, 1038 (D.C. Cir. 2012) (citing Fox,
556 U.S. at 514-15). Under this rule, the agencies do not view the
definition of ``waters of the United States'' as conclusively
determining which of the nation's waters warrant environmental
protection and which do not; rather, the agencies interpret the
definition as drawing the boundary between those waters subject to
federal requirements under the CWA and those waters that States and
Tribes are free to manage under their independent authorities. The
agencies are establishing this line-drawing based primarily on their
interpretation of their authority under the Constitution and the
language, structure, and legislative history of the CWA, as articulated
in decisions by the Supreme Court.
 Some commenters viewed the proposed rule as complicated and,
because one of the agencies' goals in proposing a new definition was to
provide simplicity and clarity, stated that the proposal failed to meet
that goal and is therefore arbitrary and capricious. The agencies
disagree with these commenters' view that the proposed rule would not
have provided necessary clarity. Notwithstanding this disagreement, the
agencies have made certain enhancements to the final rule that will
further promote clarity and provide fair notice to the public. As a
threshold matter, the agencies for the first time have streamlined the
regulatory text to four simple categories of jurisdictional waters,
provided clear exclusions for many water features that traditionally
have not been regulated, and defined the operative terms used in the
regulatory text. And while the categories of jurisdiction in the final
rule must be applied to specific facts to determine jurisdiction, the
final rule does not include a regulatory category of case-specific
jurisdiction as the 2015 Rule did in paragraphs (a)(7) and (a)(8). As
such, the agencies believe the final rule will be clearer than either
the 2015 Rule or the pre-existing regulatory regime restored by the
2019 Rule. However, clarity as an end in itself is not the primary or
fundamental basis for the final rule.
 Section III of this notice describes in detail the fundamental
bases for this rule as the text and structure of the CWA and the
constitutional boundaries within which Congress enacted the CWA. The
final rule is securely grounded in the text of the CWA and is supported
by legislative history and Supreme Court case law. As 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;
however, replacing the multi-factored case-specific significant nexus
analysis with categorically jurisdictional and categorically excluded
waters in the final rule provides clarifying value for members of the
regulated community. The application of a clear test for categorically
covered and excluded
[[Page 22271]]
waters, as presented in this final rule, is inherently less complicated
than a complex multi-factored significant nexus test that must be
applied on a case-by-case basis to countless waters and wetlands across
the nation.
 Some commenters stated that the agencies' desire to facilitate
implementation of the regulatory definition does not override the
agencies' legal obligations under the CWA, including fulfillment of the
goals of the CWA. The agencies agree in principle. The agencies have
determined that requiring surface water flow in a typical year from
relatively permanent bodies of water to traditional navigable waters
and wetlands adjacent to such waters as a core requirement of the rule
is the most faithful way of interpreting the Federal government's CWA
authority over a water. The agencies carefully considered the comments
received on the proposal and have made certain revisions to the
regulatory text that provide further clarity without sacrificing or
undermining the fundamental legal and constitutional bases for the
rule. A number of commenters stated that the proposed rule failed to
incorporate scientific and ecological principles into the definition of
``waters of the United States.'' The agencies disagree. While science
informs the agencies' interpretation of the definition of ``waters of
the United States,'' science cannot dictate where to draw the line
between Federal and State or tribal waters, as those are legal
distinctions that have been established within the overall framework
and construct of the CWA. The definition of ``waters of the United
States'' must be grounded in a legal analysis of the limits on CWA
jurisdiction reflected in the statute and Supreme Court case law. The
agencies are precluded from exceeding their authority under the CWA to
achieve specific scientific, policy, or other outcomes. Within the
legal limits of the CWA, the agencies have looked to scientific
principles to inform implementation of the final rule as the agencies
differentiate between waters of the United States and non-
jurisdictional waters and features. For example, and as discussed
further in Section III.A.1, in requiring the use of a ``typical year''
scenario to assess the surface water connection between a particular
water or wetland and a downstream water identified in paragraph (a)(1),
(2), or (3) (generally referred to as ``paragraph (a)(1) through (3)
waters'' or ``a paragraph (a)(1) through (3) water'' in this notice),
the agencies recognize the influence of precipitation,
evapotranspiration, and other climatic variables on the flow of surface
water in a tributary and its contribution of flow to downstream waters
and the hydrologic surface connection between a jurisdictional water
and an adjacent wetland. In other words, the agencies will evaluate the
flow regime of a stream and the connectedness of a wetland within the
context of what is typical for that water or wetland to avoid making
erroneous jurisdictional determinations at times that may be too wet or
too dry to be considered ``normal.'' The agencies also looked to
science to inform other aspects of the final rule; for example, in
defining the terms ``perennial,'' ``intermittent,'' and ``ephemeral'';
in establishing that wetlands separated from jurisdictional waters only
by a natural berm, bank, dune, or similar natural feature are
``inseparably bound up with'' and adjacent to those waters; and in
accounting for the connectivity gradient \33\ in deciding how to apply
key principles from the Riverside Bayview, SWANCC, and Rapanos
decisions.
---------------------------------------------------------------------------
 \33\ As part of the 2015 Rule, EPA's SAB stressed that ``the EPA
should recognize that there is a gradient of connectivity.'' See
Letter to Gina McCarthy. SAB Review of the Draft EPA Report
Connectivity of Streams and Wetlands to Downstream Waters: A Review
and Synthesis of the Scientific Evidence at 3 (Oct. 17, 2014) (``SAB
Review''). The SAB recommended that ``the interpretation of
connectivity be revised to reflect a gradient approach that
recognizes variation in the frequency, duration, magnitude,
predictability, and consequences of physical, chemical, and
biological connections.'' Id. at 2 (emphasis added); see also
Connectivity Report at 1-18 (``Variation in the degree of
connectivity is critical to the integrity and sustainability of
downstream waters, and can be described in terms of the frequency,
duration, magnitude, timing, and rate of change of fluxes to and
biological exchanges with downstream waters. These descriptors
characterize the range over which streams and wetlands vary and
shift along connectivity gradients and the probable effects of
different types (hydrologic, chemical, biological) and degrees of
connectivity over time. . . . Ultimately, differences in the
frequency, duration, magnitude, timing, and rate of change of
physical, chemical, and biological connections describe different
positions along the connectivity gradient and produce different
types of downstream effects.'').
---------------------------------------------------------------------------
 The agencies consider the priorities they have outlined to be
reasonable, especially in light of the long history of controversy and
confusion over the definition of ``waters of the United States.'' In
concurring with the Rapanos plurality opinion, Chief Justice Roberts
stated that ``[g]iven the broad, somewhat ambiguous, but clearly
limiting terms Congress employed in the Clean Water Act, the [agencies]
would have enjoyed plenty of room to operate in developing some notion
of an outer bound to the reach of their authority'' under the CWA, and
that the agencies' interpretations under the Act are ``afforded
generous leeway by the courts.'' Rapanos, 547 U.S. at 758 (Roberts,
C.J., concurring) (emphasis in original); see also id. (``Rather than
refining its view of its authority in light of our decisions in SWANCC,
. . . the Corps chose to adhere to its essentially boundless view of
the scope of its power. The upshot today is another defeat for the
agency.''). In this rule, as described in detail in Section III, the
agencies are reasonably interpreting the scope of their authority under
the Act in a manner that is consistent with its text, structure,
legislative history, and applicable Supreme Court guidance. This final
rule presents a unifying legal theory for federal jurisdiction over
those waters and wetlands that maintain a sufficient surface water
connection to traditional navigable waters or the territorial seas.
F. Summary of Final Rule as Compared to the 1986 Regulations Recodified
in the 2019 Rule and the 2015 Rule
 The agencies are finalizing a definition of ``waters of the United
States'' that they consider to be superior to the 1986 regulations re-
codified in the 2019 Rule, as well as to the 2015 Rule. The agencies
are revising previous regulatory definitions of this term to
distinguish between waters that are ``waters of the United States''
subject to Federal regulation under the CWA and waters or features that
are subject to exclusive State or tribal jurisdiction, consistent with
the scope of jurisdiction authorized under the CWA and the direction in
the Act to both ``restore and maintain the chemical, physical, and
biological integrity of the Nation's waters,'' 33 U.S.C. 1251(a), and
``recognize, preserve, and protect the primary responsibilities and
rights of States to . . . plan the development and use (including
restoration, preservation, and enhancement) of land and water resources
. . . .'' Id. at 1251(b). The Supreme Court has recognized that new
administrations may reconsider the policies of their predecessors so
long as they provide a reasonable basis for the change in approach.
Nat'l Ass'n of Home Builders, 682 F.3d at 1043 (quoting Motor Vehicle
Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 59 (1983)
(Rehnquist, J., concurring in part and dissenting in part)). The
agencies intend that the revised interpretation of the federal
regulatory scope of the CWA will resolve longstanding confusion over
broad and unclear definitions of ``waters of the United States.''
 This final rule is more consistent with the agencies'
constitutional and statutory authority than the 2015 Rule,
[[Page 22272]]
for the reasons discussed in the preamble to the 2019 Rule as well as
the rest of this section and Section III of this notice. The 2015 Rule
did not implement the legal limits on the scope of the agencies'
authority under the CWA as intended by Congress and as reflected in
Supreme Court cases, including Justice Kennedy's articulation of the
significant nexus test in Rapanos. In the 2019 Rule, the agencies
concluded that in promulgating the 2015 Rule the agencies failed to
adequately consider and accord due weight to the policy of the Congress
in CWA section 101(b) 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 . . . of land and
water resources.'' 33 U.S.C. 1251(b). The 2015 Rule interpreted the CWA
in a manner that pushed the envelope of the agencies' constitutional
and statutory authority in the absence of a clear statement from
Congress authorizing substantial encroachment upon traditional State
land-use planning authority. See Georgia v. Wheeler, No. 2:15-cv-079,
2019 WL 3949922, at *23 (S.D. Ga. Aug. 21, 2019) (finding the 2015 Rule
``unlawful'' given its ``significant intrusion on traditional state
authority'' without ``any clear or manifest statement to authorize
intrusion into that traditional state power'').
 In addition, the agencies recognize that the 2015 Rule has been
remanded by the U.S. District Court for the Southern District of Texas
for failing to comply with the APA. That court found that the 2015 Rule
suffered from several problems, including that the distance-based
limitations in the 2015 Rule were not a logical outgrowth of the
proposal in violation of the APA's public notice and comment
requirements. See Texas v. EPA, 389 F. Supp. 3d 497 (S.D. Tex. 2019).
The court found this error ``significant'' because the specific
distance-based limitations ``alter[ed] the jurisdictional scope of the
Act.'' Id. at 504. Litigants challenging the 2015 Rule alleged other
APA deficiencies, including the lack of record support for the
distance-based limitations inserted into the final rule without
adequate notice. Several commenters on the proposed repeal of the 2015
Rule raised similar concerns, arguing that the 2015 Rule was arbitrary
and capricious because of the lack of record support for those
limitations. The agencies recognize that the Federal government, in
prior briefs before the various district courts that heard challenges
to the 2015 Rule, defended the procedural steps the agencies took to
develop and support the 2015 Rule. Having considered the public
comments and relevant litigation positions, and the decision of the
Southern District of Texas on related arguments, the agencies concluded
in the 2019 rulemaking that the administrative record for the 2015 Rule
did not contain sufficient record support for the distance-based
limitations that appeared for the first time in that final rule. This
conclusion is further supported by similar findings of the U.S.
District Court for the Southern District of Georgia, which remanded the
2015 Rule to the agencies in August 2019 after identifying substantive
and procedural errors with respect to numerous provisions, including
the rule's distance limitations. Georgia v. Wheeler, 2019 WL 3949922,
at *12-32. By contrast, for the reasons discussed elsewhere in this
section and in Section III of this notice, this final rule remains
within the bounds of the agencies' authority under the Constitution and
the CWA, is properly supported by the record in this rulemaking, and is
a logical outgrowth of the NPRM.
 Finally, the agencies believe that this final rule will be clearer
than the pre-existing regulatory regime restored by the regulatory text
of the 2019 Rule and the prior implementation of that regime in
response to adverse Supreme Court decisions and agency guidance. For
the reasons discussed in the 2019 Rule preamble, that regulatory regime
is preferable to the 2015 Rule; however, a clear, comprehensive
regulation that encompasses the Supreme Court's interpretations is
preferable to the pre-existing regulatory regime restored by the 2019
Rule. The language of the 2019 Rule regulatory text leaves
substantially more room for discretion and case-by-case variation than
does this final rule, particularly paragraph (a)(3) in the 2019 Rule,
which claims jurisdiction over waters that are used by interstate or
foreign travelers for recreational or other purposes, with no reference
to navigable waters. Following the Supreme Court's opinions on the
definition of ``waters of the United States,'' particularly SWANCC and
Rapanos, the 2019 Rule must be implemented taking into account the
Court's holdings and agency guidance interpreting those cases. In the
decade since the Rapanos decision, the agencies and the public have
become familiar with this multi-layered interpretive approach, which is
in part why the agencies finalized the 2019 Rule to maintain the pre-
existing regime during the process of developing and considering public
comments on this final rule. The regulatory definition of ``waters of
the United States'' set forth in this final rule reflects Supreme Court
case law and clearly establishes the scope of jurisdictional waters
under the CWA. It provides greater regulatory predictability than the
regulatory regime restored by the 2019 Rule.
 In sum, as compared with both the 2015 Rule and the regulatory
regime restored by the 2019 Rule, this final rule more appropriately
reflects the scope of the agencies' authority under the statute and the
Constitution; respects the vital role of the States and Tribes in
managing their land and water resources; and addresses the need of the
public for predictable, more easily implementable regulations that aim
to accomplish the objective of the Act, ``to restore and maintain the
chemical, physical, and biological integrity of the Nation's waters.''
33 U.S.C. 1251(a).
G. Existing Guidance
 In several places in the preamble to the proposed rule, the
agencies solicited comment on whether they should revoke the 2003
SWANCC Guidance or the 2008 Rapanos Guidance if the agencies were to
finalize the proposal. 84 FR 4165, 4167. These guidance documents were
drafted to inform the agencies' implementation of the 1986 and 1988
regulations, which the 2019 Rule recodified, in a manner consistent
with the Supreme Court's decisions in SWANCC and Rapanos. Some
commenters thought that the 2003 and 2008 guidance documents provided
helpful information and assistance to the public in understanding how
the agencies might implement a definition of ``waters of the United
States.'' Other commenters thought that the documents should be
rescinded to avoid confusion during implementation of this final rule,
particularly because the agencies have totally restructured the
regulatory definitions. The agencies considered these comments and
conclude that, when this final rule becomes effective, these and other
related agency guidance documents, memoranda, and materials will be
rendered inoperative because they will no longer be necessary or
material, and they may in fact create confusion as the agencies
implement this final rule. The agencies can develop new guidance to
facilitate implementation of this final rule should questions arise, if
any, regarding the application of the rule to specific
circumstances.\34\
---------------------------------------------------------------------------
 \34\ To the extent that, as a result of litigation, the 1986 and
1988 regulations, which the 2019 Rule recodified, remain or become
legally effective after the effective date of this rule as a result
of litigation, the agencies intend to use the guidance documents
relevant to those regulations, including the 2003 SWANCC Guidance
and 2008 Rapanos Guidance, if necessary to inform implementation of
those regulations.
---------------------------------------------------------------------------
[[Page 22273]]
III. Definition of ``Waters of the United States''
 The following is a summary of the key elements and each substantive
provision of this final rule. Each subsection describes what the
agencies are finalizing, why the agencies are finalizing the regulatory
text, and how the agencies plan to implement the final rule. To assist
the reader, the longer subsections have internal headings.
 In this final rule the agencies interpret the term ``the waters''
in the phrase ``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. As the plurality decision in Rapanos
notes, the term ``the waters'' is most commonly understood to refer to
``streams and bodies forming geographical features such as oceans,
rivers, lakes,'' or ``the flowing or moving masses, as of waves or
floods, making up such streams or bodies.'' 547 U.S. at 732 (citing
Webster's New International Dictionary 2882 (2d ed. 1954)); see also
Riverside Bayview, 474 U.S. at 131 (characterizing ``waters of the
United States'' as including ``rivers, streams, and other hydrographic
features more conventionally identifiable as `waters' ''); see also 118
Cong. Rec. 33699 (Oct. 4, 1972) (statement of Sen. Muskie) (referring
to ``navigable waters'' as ``water bodies''). According to the Rapanos
plurality, however, the ordinary meaning of the term ``waters'' does
not include areas that are dry most of the year, and which may
occasionally contain ``transitory puddles or ephemeral flows of
water.'' 547 U.S. at 733.
 The agencies received considerable public comments on the scope of
the proposed definition of ``waters of the United States.'' Some
commenters stated that the proposed rule would include more waters and
wetlands than appropriate under a strict reading of Justice Scalia's
plurality opinion in Rapanos and is therefore inconsistent with
Executive Order 13778. Some commenters agreed with the proposed rule,
stating that it struck an appropriate balance of asserting jurisdiction
over waters that should be regulated by the Federal government,
provided clear direction for the regulated community, and respected
State and tribal authority over their own land and water resources.
Some commenters stated that the proposal failed to include ecologically
important waters and wetlands and failed to give due weight to Justice
Kennedy's concurring opinion in Rapanos. Other commenters stated that
the proposed rule and supporting rationale were based exclusively on
the CWA section 101(b) policy to ensure that States maintain primary
authority over land and water resources and failed to give due weight
to the objective in CWA section 101(a) to restore and maintain the
chemical, physical, and biological integrity of the nation's waters.
 The agencies disagree with commenters' suggestion that the
Executive Order requires the agencies to rely exclusively on Justice
Scalia's opinion in Rapanos. The Executive Order requires the agencies
to consider that opinion, which is what the agencies have done here.
The agencies also disagree with commenters' suggestion that the
proposal failed to incorporate principles from Justice Kennedy's
opinion, and further disagree with commenters' suggestion that the
agencies failed to consider the objective of section 101(a) in
determining where to draw the line of federal jurisdiction. However,
the agencies considered these and other public comments, and have made
modifications in the final rule to better incorporate common principles
of the Rapanos plurality and concurring opinions, and to strike a
careful balance between the clear directive from Congress to ensure
that States maintain primary authority over land and water resources,
and the importance of maintaining federal authority over those waters
that Congress determined should be regulated by the Federal government
under its Commerce Clause powers.
 The final definition of ``waters of the United States'' aligns with
the intent of Congress to interpret the term ``navigable waters''
beyond just commercially navigable-in-fact waters. This definition
recognizes Congress' intent ``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, but at the same time acknowledges that
``[t]he grant of authority to Congress under the Commerce Clause,
though broad, is not unlimited.'' SWANCC, 531 U.S. at 173. The
definition also recognizes the constitutional underpinning of the CWA,
which was Congress' exercise of ``its commerce power over navigation.''
Id. at 168 n.3.
 This final rule establishes categorical bright lines to improve
clarity and predictability for regulators and the regulated community
by defining ``waters of the United States'' to include the following
four categories: (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 waters that are themselves
wetlands). The final rule eliminates the case-specific application of
the agencies' previous interpretation of Justice Kennedy's significant
nexus test in the Rapanos Guidance, and instead establishes clear
categories of jurisdictional waters that adhere to the basic principles
articulated in the Riverside Bayview, SWANCC, and Rapanos decisions
while respecting the overall structure and function of the CWA.
A. Key Terms and Concepts
 Each of the four categories of waters of the United States
established by this final rule, as well as the waters that fall beyond
CWA jurisdiction, is discussed in detail in Sections III.B through
III.H below. Many of the operative terms used in the final rule are
defined in paragraph (c), and their applicability is discussed at
length throughout those subsections. This subsection summarizes a few
key terms and concepts that help inform the overall implementation of
the jurisdictional categories established by paragraph (a) and the non-
jurisdictional waters established by paragraph (b), and are highlighted
here for ease of reference and additional clarity.
 One such term is ``typical year.'' As discussed above, the meaning
of the phrase ``waters of the United States'' has been mired in
confusion for decades. This is in part because courts, regulators, the
regulated community, and members of the public have lacked clear
guidance as to how far up the watershed federal jurisdiction extends,
and what connection is required for waters to be considered part of the
regulated tributary system to traditional navigable waters and the
territorial seas. The last two Supreme Court cases on point--SWANCC and
Rapanos--provided clear instruction to the agencies that their prior
interpretations had exceeded their jurisdictional authority under the
CWA. The phrase ``typical year'' as used in the final rule and
throughout this notice is intended to provide a predictable framework
in
[[Page 22274]]
which to establish federal jurisdiction over relatively permanent
waters that contribute surface water flow to waters identified in
paragraph (a)(1) (generally referred to as ``paragraph (a)(1) waters''
or ``a paragraph (a)(1) water'' in this notice), and wetlands adjacent
to such waters. The term ``typical year'' is summarized in Section
III.A.1 and is further discussed throughout the notice.
 The agencies are also defining the terms ``perennial,''
``intermittent,'' and ``ephemeral'' in the final rule, adding clarity
and certainty for how these frequently used terms apply in the ``waters
of the United States'' context. The agencies have used these terms to
assess jurisdictional status under the CWA, but until this final rule
have never defined them in the regulatory text. The terms have specific
meaning in the scientific community, but when used in legal settings,
common parlance often converges with scientific meaning, creating
opportunities for misunderstanding. For example, while the Rapanos
plurality stated that the term ``waters of the United States'' does not
include ``ordinarily dry channels through which water occasionally or
intermittently flows,'' 547 U.S. at 733 (emphasis added), it also
stated the phrase does ``not necessarily exclude 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).
``Seasonal rivers''--which the plurality would not categorically
exclude--are known among scientists as ``intermittent streams''--which
the plurality stated it would exclude. The plurality also appears to
confuse the scientific understanding of the terms `` `intermittent' and
`ephemeral' streams,'' conflating them to mean ``streams whose flow is
. . . `existing only, or no longer than, a day[.]' '' Id. Indeed, this
description more accurately captures the hydrological definition of
``ephemeral streams'' which only flow during or in immediate response
to rainfall. By contrast, ``intermittent streams'' typically flow for a
more continuous period like the ``seasonal rivers'' the plurality
describes. Because the definition of ``tributary'' specifically uses
and relies on the terms ``perennial'' and ``intermittent,'' but not
``ephemeral,'' the agencies are clearly defining these terms in the
final rule. These terms are summarized below in Section III.A.2 and are
further discussed throughout the preamble.
 Another challenging issue that has confounded the meaning of
``waters of the United States'' for years is what types of natural or
artificial features potentially sever jurisdiction between the upstream
and downstream portions of a waterway. For example, if the waters of a
perennial headwater stream are diverted to another basin for
consumptive use and the downstream reach runs dry for major portions of
a year, or the flow of a stream disappears into the desert floor before
reaching a traditional navigable water, questions are frequently raised
regarding the jurisdictional status of those waters. Subsection III.A.3
below discusses the ``breaks'' topic in detail and how the agencies
have addressed the various artificial and natural features that either
maintain or sever jurisdiction under the final rule.
1. Typical Year
 In this final rule, the agencies use the term ``typical year'' to
help establish the surface water connection between a relatively
permanent body of water and traditional navigable waters, and between
certain wetlands and other jurisdictional waters, that is sufficient to
warrant federal jurisdiction. ``Typical year'' is defined in the final
rule to mean 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. Under this final definition, a typical year would
generally not include times of drought or extreme flooding. In other
words, the purpose of the term is to ensure that flow characteristics
are not assessed under conditions that are too wet or are too dry. As
discussed in Section III.G.2, climatic conditions, including flow or
flooding, that may occur under ``typical year'' conditions do not
necessarily occur in every calendar year.
 The agencies proposed to use the term ``typical year'' to mean
within the normal range of precipitation over a rolling thirty-year
period for a particular geographic area; that is, during times when it
is not too wet and not too dry. However, some commenters on the
proposed rule expressed confusion about the proposed ``typical year''
definition, including how it is calculated and what timeframe it
represents. Commenters also expressed concern that the proposed
definition included only precipitation as a driver of streamflow
classification. Other commenters supported the typical year concept as
proposed. In response to these comments, the agencies have modified the
definition of ``typical year'' to expressly include other climatic
variables in addition to precipitation and additional description of
the normal periodic range, signaling that such range need not be based
on a calendar year. The agencies believe the revised definition more
appropriately reflects what the agencies intended to measure, which is,
simply put, the characteristics of a waterbody at times that are not
too wet and not too dry.
 To determine whether water features are being assessed during
normal precipitation conditions, the agencies currently use data from
the National Oceanic and Atmospheric Administration's (NOAA) Global
Historic Climatology Network, which integrates climate data from over
20 sources. The agencies evaluate normal precipitation conditions based
on the three 30-day periods preceding the observation date. For each
period, a weighted condition value is assigned by determining whether
the 30-day precipitation total falls within, above, or below the 70th
and 30th percentiles for totals from the same date range over the
preceding 30 years. The agencies make a determination of ``normal,''
``wetter than normal,'' or ``drier than normal'' based on the condition
value sum. While the agencies will generally use this method to
implement this final rule, the agencies also recognize there may be
other accurate and reliable measurements of normal precipitation
conditions and will make adjustments to the approach as is
scientifically warranted. The agencies may also consider alternative
methods that are developed and appropriately validated, including
different statistical percentiles, evaluation periods, or weighting
approaches for condition values.
 Some commenters on the proposed rule were concerned that a 30-year
period may be too long or too short of a record, or that rolling 30-
year climate percentiles would be difficult to calculate. The agencies
have concluded that a rolling 30-year period would account for
variability to provide a reliable indicator of the climate in a given
geographic area without being confounded by a year or two of unusual
climate data. A standard timeframe is necessary to ensure consistent
application across the country, and 30 years is the most common and
recognized timeframe utilized in other government climatic data
programs (e.g., NOAA's National Climatic Data Center climate normals,
which are based on World Meteorological Organization requirements).
Nearly a century ago, the International Meteorological Organization,
now known as the World Metrological Organization, instructed member
nations to calculate climate normals using 30-year periods, beginning
with 1901 to 1930 (see https://www.ncdc.noaa.gov/news/
[[Page 22275]]
defining-climate-normals-new-ways). Recognizing that precipitation and
temperature change over time, the agencies have determined that a
rolling 30-year record is necessary to ensure that changing conditions
are captured by the calculation. The agencies have considered other
alternative time periods and are maintaining the well-established 30-
year period.
 The agencies proposed that the geographic area be on a watershed-
scale basis to ensure specific climatic data are representative of the
landscape in relation to the feature under consideration for meeting
the ``tributary'' definition and sought comment on the appropriate
watershed scale. Some commenters on the proposed rule suggested
constraining precipitation data sources to the smallest practicable
watershed scale (e.g., a USGS HUC-12 scale). However, other commenters
noted that 30 years of data may not always be available at that scale,
and other considerations such as distance or ecoregion are also
important for identifying appropriate climatic data. In response to
these comments, the agencies have determined that specifying a
particular watershed size or Hydrologic Unit Code (HUC) could preclude
the use of the best available data sources, but that watershed
boundaries should be a consideration when selecting climate records.
Other considerations should include data availability, topography, and
distance of climatic data collection in relation to the aquatic
resource location.
 The agencies recognize that precipitation data may not be the only
appropriate indicator for determining ``typical year,'' as was noted by
many commenters on the proposed rule. Although the agencies will
generally use the methodology described in this notice for determining
normal precipitation conditions, the agencies will consider and use the
best available data and information, which provides the most accurate
and reliable representative information for the aquatic resource in
question, to determine ``typical year.'' For instance, determinations
of ``typical year'' based on precipitation totals may conflict with
other sources of information such as drought indices, which account for
other hydrologic factors like evapotranspiration and water storage. The
agencies currently use professional judgment and a weight of evidence
approach as they consider precipitation normalcy along with other
available data sources. These data sources include, but are not limited
to, the Web-based Water-Budget Interactive Modeling Program (WebWIMP)
for approximate dates of wet and dry seasons for any terrestrial
location based on average monthly precipitation and estimated
evapotranspiration (http://climate.geog.udel.edu/~wimp/); Climate
Analysis for Wetlands Tables (known as WETS tables, or similar tools,
as the WETS tables are currently in a fixed 30-year timeframe), which
are provided by the NRCS National Water and Climate Center (https://www.wcc.nrcs.usda.gov/climate/wets_doc.html) and were calculated from
long-term (30-year) weather records gathered at National Weather
Service meteorological stations; and drought indices, such as the
Palmer Drought Severity Index (PDSI) (Sprecher and Warne 2000), where
time-series plots of PDSI values by month or year are available from
the National Climatic Data Center (https://www.ncdc.noaa.gov/temp-and-precip/drought/historical-palmers/psi/201811-201910 or https://www.cpc.ncep.noaa.gov/products/monitoring_and_data/drought.shtml).
2. Perennial, Intermittent, and Ephemeral
 Though ``perennial,'' ``intermittent,'' and ``ephemeral'' are
commonly used scientific terms, the agencies are including definitions
of these terms in the final rule to ensure that the regulation is
clear. In this final rule, the agencies define the term ``perennial''
to mean surface water flowing continuously year-round. The term
``intermittent'' in the final rule means surface water flowing
continuously during certain times of the year and more than in direct
response to precipitation (e.g., seasonally when the groundwater table
is elevated or when snowpack melts). The phrase ``certain times of the
year'' is intended to include extended periods of predictable,
continuous surface flow occurring in the same geographic feature year
after year. Continuous surface water flow during certain times of the
year may occur seasonally such as in the spring when evapotranspiration
is low and the groundwater table is elevated. Under these conditions,
the groundwater table intersects the channel bed and groundwater
provides continuous baseflow for weeks or months at a time even when it
is not raining or has not very recently rained. Melting snowpack can be
the sole or primary source of perennial or intermittent flow in a
tributary. The term ``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).'' Perennial or intermittent flow in certain mountain streams,
for example, may result primarily from melting snowpack, not from
groundwater contributions to the channel. The term ``ephemeral'' in the
final rule means surface water flowing or pooling only in direct
response to precipitation, such as rain or snow fall. With these
definitions, the agencies distinguish ephemeral flow resulting from a
snow fall event from sustained intermittent flow resulting from melting
snowpack that is continuous, such as for weeks or months at a time.
 Some commenters requested that the final rule require that
groundwater must be the source for perennial and intermittent flow in
tributaries. The agencies recognize that groundwater input is an
element of most scientific definitions of perennial and intermittent
flow,\35\ but have decided not to mandate groundwater input as part of
the definition of ``perennial'' or ``intermittent'' in the final rule.
As a threshold matter, the agencies believe that such an approach would
too narrowly limit CWA jurisdiction over waters that provide continuous
or intermittent and predictable flow to traditional navigable waters in
a typical year. For example, many headwater streams in mountainous
regions flow through channels incised in bedrock with no groundwater
interface with the bed of the stream. These streams instead are fed by
glacial or high elevation snowpack melt. The same scenario may also
exist in northern climes, where spring flows could be fed almost
exclusively through melting snowpack absent elevated groundwater
tables. Mandating a groundwater interface and contribution of flow
could also be challenging to implement, as identifying whether the
channel bed intersects the groundwater table may be difficult to
accomplish in the field, gathering the relevant data could be time
consuming, and implementing a source water-based definition could
require new tools and training of field staff and the regulated public.
The requirement for a groundwater flow source could also render
effluent-dependent streams non-jurisdictional. The agencies do not
interpret the text or legislative history of the CWA or Supreme Court
guidance to mandate groundwater input as a condition precedent for
asserting jurisdiction over tributaries to traditional navigable
waters.
---------------------------------------------------------------------------
 \35\ See, e.g., 82 FR 2006 (Jan. 6, 2017) (Corps nationwide
permit program); National Research Council. 2002. Riparian Areas:
Functions and Strategies for Management. Washington, DC: The
National Academies Press. https://doi.org/10.17226/10327.
---------------------------------------------------------------------------
 A few commenters asked for clarification to better distinguish
[[Page 22276]]
between flow ``in direct response to precipitation'' versus ``more than
in direct response to precipitation,'' as well as further clarification
on the distinction between ephemeral and intermittent flow
classifications in general. For example, they requested clarification
on whether streams that flow continuously during a rainy season (e.g.,
monsoon-driven streams in the arid West) are considered intermittent.
The use of the term ``direct'' by the agencies in the proposed rule and
maintained in this final rule is intended to distinguish between flow
solely caused by individual precipitation events (including multiple,
individual back-to-back storms), and continuous flow resulting, for
example, from weeks- or months-long accumulation of precipitation in
the form of snowpack that melts slowly over time or an elevated
groundwater table that provides baseflow to the channel bed.
 Ephemeral flow may occur simply because it is raining or has very
recently rained or it has recently snowed and the snow has melted. For
example, ephemeral flow could be the result of a small, brief storm
event, one long storm event producing rainfall for several days without
pause, or several back-to-back storms. Continuous flow occurring more
than in direct response to precipitation could include ``seasonal''
flow, such as when snowpack melts or when groundwater is elevated and
provides baseflow to the channel bed. Streamflow that occurs during the
monsoon season in certain parts of the country (typically June through
September in the arid West) may be ephemeral or intermittent, with the
distinction made according to the definition of each term in the final
rule. For example, a stream in the arid West is ephemeral if it flows
only in direct response to rainfall, even if the flow may appear
relatively continuous as a result of multiple, individual storms during
the monsoon season. On the other hand, when monsoon floodwaters locally
recharge the riparian aquifer through bank infiltration and supply
sustained baseflow to streams in the arid West when it is not raining
or has not recently rained, such streams meet the rule's definition of
``intermittent'' if they flow seasonally, for example, or ``perennial''
if they flow continuously year-round.\36\
---------------------------------------------------------------------------
 \36\ See e.g., Baillie, M.N., J.F. Hogan, B. Ekwurzel, A.K.
Wahi, and C.J. Eastoe. 2007. Quantifying water sources to a semiarid
riparian ecosystem, San Pedro River, Arizona, J. Geophysical Res.,
112, GO3S02, doi: 10.1029/2006JG000263. Ballie et al. (2007) found
that locally recharged monsoon floodwater is one of the dominant
water sources in the main stem of the spatially intermittent San
Pedro River in Arizona. The authors also define ``monsoon storms''
as ``short, intense rainstorms that generate significant amounts of
flooding and ephemeral flow (i.e., flow in ephemeral channels on the
basin floor) and represent, on average, the bulk of summer
moisture.'' (Emphasis added). See also Connectivity Report at B-39
(``Monsoon-generated, short-duration runoff dominates the San Pedro
watershed. . . Most perennial and intermittent rivers in the
Southwest are groundwater dependent, flowing primarily in a baseflow
regime and supported by discharge from a connected regional or
alluvial aquifer or both. . . . [P]art of the baseflow is often
sustained or augmented by slow drainage of a shallow alluvial
aquifer from past flooding.'')
---------------------------------------------------------------------------
 Some commenters requested clarity on the specific geographic
regions where ``snowpack'' as defined under the proposed rule would
occur. Other commenters requested that the agencies clarify how melting
snowpack is distinguished from melting snowfall and clearly articulate
the amount of snow needed to meet the definition of ``snowpack,'' as
well as provide clarity on what ``extended periods'' of time means.
They also requested clarification on the sources of information (e.g.,
from NOAA, NRCS, or another source) that can be used to identify
``snowpack.'' ``Extended periods of time'' refers to more than merely a
single snowfall event or periodic events with repeated snowmelts after
each occurrence, but rather recurring snow events which result in an
accumulation of multiple layers of snow in certain geographic regions,
which may include, for example, parts of North Dakota or Alaska, or at
high elevation, to potentially include the Rocky, Sierra Nevada, or
Cascade mountains. A foot of new snow fall on the high plains of
southern Wyoming in May will typically melt quickly under the intense
sun of subsequent days, while a foot of snow in northern Wisconsin in
January will likely contribute to seasonal snowpack that may not melt
until spring thaw. The first scenario is more likely to cause ephemeral
flow, the second is more likely to cause intermittent flow. The
agencies could consider any data sources that provide an accurate
estimation of ``snowpack'' in identifying that feature. The agencies
are not limiting the identification of snowpack to one data source,
such as those provided by NOAA or NRCS, although those are reliable
existing sources to find information on snowpack. The Bureau of
Reclamation and several western States depend on accurate snow fall and
accumulation data to project water availability for consumptive needs
and the allocation of water rights. Analyzing the location and
seasonality of snowpack is a common, well understood practice in other
contexts and will not pose implementation challenges to the agencies
under the final rule as they draw on the expertise of other Federal and
State partners.
 In certain parts of the country and during certain times of the
year, snowpack may have a more significant influence on flow
classifications than rainfall. Sources of information on ``snowpack''
can be found in the NOAA national snow analyses maps (https://www.nohrsc.noaa.gov/nsa/), in NRCS sources (https://www.wcc.nrcs.usda.gov/snow/), or by using hydrographs of subject
locations as a potential guide to alert the regulated public and
regulators as to which regions of the country have to consider snowpack
scenarios. In these regions, for example, a hydrograph could indicate a
large increase in discharge volume due to the late spring/early summer
thaws of melting snowpack. These are indicators of a regular,
predictable, seasonal occurrence of flow. The large water contribution
source for those northern geographic regions which do not have
significant elevation changes, but which do have a consistent,
predictable snowfall that accumulates on the ground for extended
periods of time, are covered in this rule's definition of ``snowpack''
in paragraph (c)(10), in addition to mountainous regions with snowpack.
3. Breaks
 Under the proposed rule, an artificial or natural ephemeral feature
(e.g., an ordinarily dry channel only flowing during or in immediate
response to precipitation) occurring in a typical year at any point
along a tributary network would have severed jurisdiction upstream of
the ``break'' because the waterbody would not convey surface water to a
paragraph (a)(1) water year-round or continuously for extended periods
of time. 84 FR 4173-74. To be jurisdictional, lakes and ponds that are
not paragraph (a)(1) waters would have needed to maintain perennial or
intermittent flow to a paragraph (a)(1) water in a typical year or be
flooded by a jurisdictional water in a typical year. Id. at 4182. In
other words, to be jurisdictional, the proposed rule would have
required tributaries and most lakes and ponds to maintain a perennial
or intermittent surface water connection all the way to a downstream
paragraph (a)(1) water. The agencies received public comments
indicating that this approach could affect the jurisdictional status of
many waters, particularly in the arid West; that it could inadvertently
subject otherwise exempt water transfers to CWA section 402 permitting;
and it could create
[[Page 22277]]
implementation challenges. The agencies received other comments
supporting the proposed approach.
 As further discussed below, the final rule contains some important
changes to address these concerns, which are intended to better
incorporate common principles from the Rapanos plurality and concurring
opinions, and to strike a better balance between the objective and
policy in CWA sections 101(a) and 101(b), respectively. Changes made in
the final rule, however, remain faithful to the overall text,
structure, and legislative history of the CWA and the legal principles
outlined in Section II.E. Many of the changes were designed to address
questions and concerns regarding under what circumstances a natural or
artificial feature severed upstream jurisdiction, as discussed in
detail in this subsection and as further explained throughout Section
III.
 The Supreme Court has not spoken directly to the question of
whether a non-jurisdictional ephemeral break along or downstream of an
otherwise jurisdictional tributary, lake, pond, or impoundment would
sever jurisdiction of upstream waters. As described in Section II.E,
Supreme Court precedent provides some insight regarding CWA
jurisdiction of relatively permanent bodies of water, including
tributaries, lakes, and ponds, and their connection to traditional
navigable waters, but it does not provide comprehensive guidance. For
example, the Rapanos plurality describes a ``water of the United
States'' as ``a relatively permanent body of water connected to
traditional interstate navigable waters[.]'' Rapanos, 547 U.S. at 742
(emphasis added). Regarding the connection between a water in question
and downstream navigable waters, Justice Kennedy noted that ``in some
instances, as exemplified by Riverside Bayview, the connection between
a nonnavigable water . . . and a navigable water may be so close, or
potentially so close, that the Corps may deem the water . . . a
`navigable water' under the Act. In other instances, as exemplified by
SWANCC, there may be little or no connection.'' Id. at. 767. Justice
Kennedy also stated that ``mere hydrologic connection should not
suffice in all cases; the connection may be too insubstantial for the
hydrologic linkage to establish the required nexus with navigable
waters as traditionally understood.'' Id. at 784-85.
 Although the Rapanos plurality opinion did not specify what would
constitute a sufficient connection between relatively permanent waters
and downstream traditional navigable waters, it did signal types of
connections that are likely insufficient to maintain jurisdiction when
read in context with the principles articulated throughout the balance
of the opinion. For instance, the plurality characterized an
``expansive definition of `tributaries' '' as including ``dry arroyos
connected to remote waters through the flow of groundwater over
`centuries,' '' id. at 725-26 (internal citations omitted), and
described federal control over ``irrigation ditches and drains that
intermittently connect to covered waters'' as ``sweeping assertions of
jurisdiction.'' Id. at 726-27. In addition to ``tributaries,'' the
plurality noted with disapproval that the Corps and lower courts had
``define[d] `adjacent' wetlands broadly'' to include wetlands
``hydrologically connected'' ``to covered waters'' `` `through
directional sheet flow during storm events,' '' and wetlands
``connected to the navigable water by flooding, on average, once every
100 years[.]'' Id. at 728. The agencies considered these observations
in developing the final rule but recognize that the Supreme Court has
not spoken directly to every aspect of the agencies' existing
regulations or every fact pattern that may raise questions of federal
jurisdiction. The final rule therefore is also based on the text,
structure, and legislative history of the CWA, the reasoned policy
choices of the executive branch agencies authorized by Congress to
implement the Act, and the agencies' technical and scientific expertise
administering the CWA over nearly five decades.
 The proposed rule, which would have severed jurisdiction upstream
of any ephemeral feature, reflected a reasonable interpretation of the
CWA and incorporated relevant Supreme Court guidance. However, upon
further consideration, the agencies conclude that the proposed rule's
treatment of ephemeral features would have severed jurisdiction for
certain relatively permanent bodies of water that are regularly
``connected to'' traditional navigable waters via channelized surface
water flow, allowing such waters to connect and become
indistinguishable when flowing. Some ephemeral reaches between upstream
and downstream relatively permanent (i.e., perennial or intermittent)
waters convey surface water from the upstream water to the downstream
covered water during a typical year. These reaches allow upstream
relatively permanent jurisdictional waters to have a surface water
connection to downstream jurisdictional waters in a typical year when
there is sufficient water in the system. In contrast, other ephemeral
streams, including those at the very headwaters of a channel network,
do not connect relatively permanent jurisdictional waters to downstream
jurisdictional waters; rather, they are merely ``channels that
periodically provide drainage for rainfall.'' Rapanos, 547 U.S at 739
(Scalia, J. plurality). The agencies conclude in this final rule that
certain ephemeral features between upstream relatively permanent
jurisdictional waters and downstream jurisdictional waters do not sever
jurisdiction upstream so long as such features satisfy the conditions
described further below. Like the proposed treatment of ephemeral
features, the final rule is based on an equally reasonable
interpretation of the CWA and Supreme Court precedent, and
appropriately balances the plurality and concurring opinions in Rapanos
and the objective of the Act and the policy of Congress set forth in
CWA sections 101(a) and 101(b).
 In the final rule, certain ephemeral features do not sever
jurisdiction of an upstream relatively permanent jurisdictional water
so long as they provide a surface water connection to a downstream
jurisdictional water in a typical year. Specifically, the final rule
provides that a tributary does not lose its jurisdictional status if it
contributes surface water flow in a typical year to a downstream
jurisdictional water through a channelized non-jurisdictional surface
water feature, through a subterranean river, through a culvert, dam,
tunnel, or similar artificial feature, or through a debris pile,
boulder field, or similar natural feature. See paragraph (c)(12). The
final rule applies the same basic principles to the category of lakes,
ponds, and impoundments of jurisdictional waters. See paragraph (c)(6).
A lake, pond, or impoundment of a jurisdictional water does not lose
its jurisdictional status if it contributes surface water flow to a
downstream jurisdictional water in a typical year through artificial
features such as culverts and spillways. The agencies conclude that
such features do not necessarily sever jurisdiction of upstream waters.
However, if an artificial feature does not allow for the contribution
of surface water flow to a downstream jurisdictional water in a typical
year, it severs jurisdiction upstream of the artificial feature. The
final rule treats natural features such as debris piles and boulder
fields the same way that it treats the artificial features described
above.
 The changes made in the final rule address concerns raised by
commenters about features that would sever the jurisdiction of upstream
portions of the
[[Page 22278]]
tributary network, including relatively permanent upstream waters that
contribute surface water flow to downstream waters when enough water is
in the system. It also addresses concerns raised by water management
interests that suggested the proposed rule could have inadvertently
undermined the NPDES permitting exemption authorized by the EPA's Water
Transfers Rule, 73 FR 33697 (June 13, 2008). That rule does not require
NDPES permits for water transfers between waters of the United States
because they do not result in the ``addition'' of a pollutant. Id. at
33699. In many regions of the country, particularly the arid West,
inter- and intra-basin water transfers may originate in perennial or
intermittent waters that may be disconnected from downstream waters by
ephemeral breaks. In many circumstances, those ephemeral breaks may be
caused by water management systems, including through water transfers,
water storage reservoirs, flood irrigation channels, and similar
structures. Not all diversions will cause a downstream portion of an
otherwise perennial or intermittent stream to become ephemeral in a
typical year; however, the modifications made by the final rule to the
categories of tributaries and of lakes, ponds, and impoundments of
jurisdictional waters help address the concerns raised by commenters
regarding the potential impact of the proposed rule on longstanding
water management practices in this country. The agencies are cognizant
of the importance of water management in the States and the explicit
policy directives of Congress to recognize the authority of States to
allocate and manage water resources within their respective
jurisdictions. See 33 U.S.C. 1251(g), 1370.
 Under the final rule, ephemeral features and other excluded
artificial and natural features are not jurisdictional and do not
become jurisdictional even if they episodically convey surface water
from upstream relatively permanent jurisdictional waters to downstream
jurisdictional waters in a typical year, and thereby help maintain the
jurisdictional status of the upstream waters. This approach
incorporates the plurality's requirement that jurisdictional waters be
continuously present, fixed bodies of water and that dry channels,
transitory puddles, and ephemeral flows be excluded from jurisdiction.
547 U.S. at 733-34; see also id. at 731 (``[T]he CWA authorizes federal
jurisdiction only over `waters.' 33 U. S. C. 1362(7).''). This approach
also requires a regular and predictable surface water connection--one
that occurs in a typical year--which addresses Justice Kennedy's
concern that speculative and insubstantial connections may not be
sufficient to establish jurisdiction. Id. at 784-86. The types of
connections that maintain jurisdiction between relatively permanent
bodies of water are described more fully below.
 The agencies conclude that tributaries, lakes, ponds, and
impoundments of jurisdictional waters that are relatively permanent
flowing or standing waterbodies upstream of certain excluded features
are jurisdictional so long as the non-jurisdictional feature maintains
a channelized surface water connection to downstream jurisdictional
waters in a typical year. Paragraph (b) of the final regulation
identifies twelve categories of excluded features, but only those
features that convey channelized surface flow between upstream
relatively permanent waters and downstream jurisdictional waters in a
typical year can maintain jurisdiction of the upstream waters. For
example, non-jurisdictional ditches could be capable of conveying
channelized surface water flow between upstream relatively permanent
jurisdictional waters and downstream jurisdictional waters in a typical
year. Similarly, a surface water connection may occur through an
ephemeral channelized conveyance and may result in the mixing of
upstream and downstream relatively permanent waters following
sufficient precipitation, but in all cases such a connection must occur
in a typical year.
 The final rule also provides that other types of artificial or
natural features, such as dams or boulder fields, may maintain
jurisdiction so long as they convey surface water flow from an upstream
tributary, lake, pond or impoundment of a jurisdictional water to a
downstream jurisdictional water in a typical year. The agencies have
concluded that water flowing through features such as dams or boulder
fields can sustain a regular and predictable surface connection between
upstream and downstream waters and therefore can maintain jurisdiction
between such waters.
 By contrast, diffuse stormwater runoff and directional sheet flow
by their very nature do not convey channelized surface flow and do not
provide regular and predictable surface water connections between
upstream relatively permanent bodies of water and downstream
jurisdictional waters. Unchannelized surface flow, such as diffuse
runoff or overland sheet flow, lacks an adequate physical indicator of
regular surface flow and can be ubiquitous across the landscape,
occurring over parking lots and lawns, for example. As Justice Kennedy
notes in Rapanos, ``mere hydrologic connection should not suffice in
all cases[,]'' 547 U.S. at 784, and the agencies agree with the Rapanos
plurality that ``[t]he plain language of the statute simply does not
authorize [a] `Land is Waters' approach to federal jurisdiction.'' Id.
at 734. The agencies ``must necessarily choose some point at which
water ends and land begins[,]'' Riverside Bayview, 474 U.S. at 132, and
conclude that diffuse runoff and overland sheet flow connections are
``too insubstantial for the hydrologic linkage to establish the
required nexus with navigable waters as traditionally understood.''
Rapanos, 547 U.S. at 784-85 (Kennedy, J. concurring in the judgment).
In this final rule, the agencies therefore conclude that surface water
flowing as unchannelized runoff or sheet flow over land cannot sustain
a regular or predictable surface water connection between upstream and
downstream waters and therefore cannot maintain jurisdiction between
such waters. By contrast, channelized ephemeral features may indicate
that surface water predictably moves from upstream relatively permanent
waters to downstream jurisdictional waters, such that they may be
capable of providing a surface water connection sufficient to warrant
federal regulation over the upstream water. As noted above, a non-
jurisdictional feature remains non-jurisdictional even if it provides a
channelized surface water connection between jurisdictional waters in a
typical year.
 Like diffuse overland flow, the agencies also conclude that
relatively permanent bodies of water that are connected to downstream
jurisdictional waters only via groundwater are not jurisdictional and
are more appropriately regulated by the States and Tribes under their
sovereign authorities. The agencies have long interpreted the CWA as
not authorizing jurisdiction over groundwater and have historically
excluded groundwater from the definition of ``waters of the United
States.'' The agencies are retaining that longstanding principle in
this final rule. See paragraph (b)(2). If groundwater is not
jurisdictional, it also makes practical sense that surface water
features connected only via groundwater likewise are not
jurisdictional. See Rapanos, 547 U.S. at 725-26 (Scalia, J., plurality)
(identifying groundwater connections as an example of the expansive
interpretation of
[[Page 22279]]
tributaries under the Act). The term ``navigable'' as used in the
statute must be given some meaning, see SWANCC, 531 U.S. at 172, and
regulating surface waters with no surface water connection to
traditionally navigable waters stretches that meaning ``beyond
parody.'' Rapanos, 547 U.S. at 734 (Scalia, J., plurality). There are,
however, certain unique subsurface connections that could maintain
jurisdiction as discussed below; the agencies recognize that there are
some relatively permanent tributaries that are relocated below ground
to allow reasonable development to occur.
 In urban areas, for example, it can be common for surface waters to
be buried underground through an artificial tunnel system to facilitate
urban development. See, e.g., Connectivity Report at 3-3. Examples
include Jones Falls, which flows under Baltimore, Maryland, and
daylights into the Baltimore's Inner Harbor; Park River which flows
under Hartford, Connecticut, and daylights into the Connecticut River;
and Mill Creek, a tributary of Lake Erie, which is diverted underground
beneath downtown Erie, Pennsylvania, and daylights into Presque Isle
Bay. These underground tunnels and similar channelized subsurface
features do not become groundwater, even though they flow under the
surface of the ground for a period of time. These features do not break
the jurisdictional status of upstream tributaries subject to the
conditions of paragraph (c)(12). In some cases where such channels
never return to the surface or otherwise do not contribute surface
water flow to a paragraph (a)(1) water in a typical year, the upstream
surface water features may not be jurisdictional under the final rule.
In all cases, the underground or buried portion of a channel network is
not jurisdictional under the final rule. By comparison, tributaries
that are relocated through a ditch or similar artificial surface
channel are jurisdictional under the final rule so long as they
continue to meet the flow conditions of paragraph (c)(12), including
through the relocated portion.
 In very limited circumstances, a tributary can naturally,
temporarily flow underground as a channelized river or stream,
maintaining the same or very nearly the same flow volume underground
and at the downstream point where it returns to the surface. These
natural systems are commonly referred to as subterranean rivers or
streams and can occur as a result of unique geologic formations, such
as sink holes and lava tubes. Examples include the Popo Agie River in
Wyoming, which becomes subterranean and daylights about a quarter of a
mile downstream; the Lost River in Indiana, which flows underground for
eight miles from where it disappears, to where it rises at two places
to flow aboveground again; and formations like the St. Marks and Santa
Fe Rivers in Florida, which flow into large sinkholes and reappear a
little over one-half mile and three miles downstream, respectively. The
agencies do not consider subterranean rivers to be groundwater, even
though they flow under the surface of the ground for what is generally
a short period of time through subterranean natural channels. Although
it has never been promulgated in regulatory text, the agencies have
historically treated these subterranean flowing connections as not
severing jurisdiction over the upstream surface channel, and the Corps
has developed expertise in performing field verifications for these
unique waters. The final rule does not change this longstanding
practice and for the first time provides certainty and transparency
regarding the agencies' approach for making jurisdictional
determinations. The agencies have added the phrase ``subterranean
river'' to paragraph (c)(12) to clarify that subterranean rivers, as
compared to groundwater and other subsurface waters, may not break
jurisdiction of upstream tributaries, including any jurisdictional
lakes, ponds, and impoundments of jurisdictional waters that contribute
surface water flow through these tributaries, depending on the factual
circumstances. These subterranean rivers are distinguished in this
final rule from other surface waters that, for example, may disappear
underground and never daylight or daylight as an aquifer-fed spring or
headwater of another river.\37\ The final rule does not maintain
jurisdiction upstream of these other surface waters that may disappear
underground and become part of the aquifer because the aquifer holds
groundwater. The agencies have concluded that groundwater connections
are an insufficient basis to assert jurisdiction over otherwise
disconnected waters. In all cases, the underground portions of all
waters are not jurisdictional under the final rule.
---------------------------------------------------------------------------
 \37\ See Connectivity Report at A-1, defining ``aquifer'' as
``[a] geologic formation (e.g., soil, rock, alluvium) with permeable
materials partially or fully saturated with ground water that yields
ground water to a well, spring, or stream.'' (emphasis added).
---------------------------------------------------------------------------
 The final rule also establishes that waters that do not contribute
surface water to a downstream territorial sea or traditional navigable
water in a typical year are not jurisdictional. These waters include
completely losing streams (e.g., streams that experience a complete
loss of surface water to a groundwater system) that do not reach
traditional navigable waters in a typical year and waters that connect
downstream only as a result of precipitation events that generally do
not occur in a typical year (e.g., 10-, 25-, 50-, 100- or 500-year
storms or floods). These waters do not provide a regular surface water
connection to jurisdictional waters. Given that the term ``navigable''
must be given some effect, and that the Supreme Court has cautioned the
agencies to avoid interpretations of the statute that raise significant
constitutional questions, the agencies conclude that such waters are
more properly regulated as land and water resources of the States and
Tribes. See SWANCC, 531 U.S. at 173.
 As described in detail in Section III.G, adjacent wetlands are
subject to a different jurisdictional test than tributaries, lakes,
ponds, and impoundments of jurisdictional waters. According to the
Rapanos plurality, for example, to be ``waters of the United States,''
a tributary, lake, pond, or impoundment must be ``a relatively
permanent body of water connected to traditional interstate navigable
waters,'' 547 U.S. at 742 (Scalia, J., plurality); to be ``waters of
the United States,'' a wetland must have ``a continuous surface
connection'' to such relatively permanent waters, ``making it difficult
to determine where the `water' ends and the `wetland begins.'' Id. The
final rule defines ``adjacent wetlands'' to include all wetlands that
abut--meaning to touch at least one point or side of--a territorial
sea, traditional navigable water, tributary, lake, pond, or impoundment
of a jurisdictional water. The final rule also includes other wetlands
that are inseparably bound up with jurisdictional waters and relies on
certain regular hydrologic surface connections to establish
jurisdiction. For instance, the ``adjacent wetlands'' definition
includes wetlands physically separated only by artificial structures
such as dikes, or barriers, or divided by roads and similar structures
so long as the structure allows for a direct hydrologic surface
connection in a typical year: For example, through a culvert, flood or
tide gate, pump, or similar feature. Jurisdiction of the wetland is
severed when, in a typical year, an artificial feature does not allow
for a direct hydrologic surface connection between the wetland and the
jurisdictional water, or the wetland is not inundated by flooding from
a territorial sea, traditional navigable
[[Page 22280]]
water, tributary, lake, pond, or impoundment of a jurisdictional water.
See 547 U.S. at 742 (Scalia, J., plurality) (such wetlands ``do not
implicate the boundary-drawing problem of Riverside Bayview,'' and thus
do not have the ``necessary connection'' to jurisdictional waters that
triggers CWA jurisdiction); see also id. at 747 (the plurality found
``no support for the inclusion of physically unconnected wetlands as
covered `waters' '').
 Wetlands are jurisdictional if they are inundated by flooding from
a territorial sea, traditional navigable water, tributary, lake, pond,
or impoundment of a jurisdictional water in a typical year. The
agencies conclude that these wetlands are inseparably bound up with
their adjacent jurisdictional waters and are therefore jurisdictional.
See Rapanos, 547 U.S. at 732 (Scalia, J., plurality) (quoting Webster's
New International Dictionary 2882 (2d ed. 1954)) (recognizing floods as
``making up such streams or bodies'' of water); id. at 740 (recognizing
the principle that wetlands that adjoin other jurisdictional waters are
part of those waters for purposes of CWA jurisdiction). The final rule
likewise asserts jurisdiction over lakes, ponds, and impoundments of
jurisdictional waters that are inundated in a typical year by flooding
from a territorial sea, traditional navigable water, tributary, or
another lake, pond, or impoundment of a jurisdictional water.
 The final rule also provides that wetlands separated from
jurisdictional waters only by a natural berm, bank, dune, or other
similar natural feature are adjacent wetlands. These natural features
are indicators of a sufficient hydrologic surface connection between
the jurisdictional water and the wetland, and the agencies conclude
that wetlands that are separated from jurisdictional waters only by
such features are inseparably bound up with the adjacent jurisdictional
waters and are therefore ``part of those waters.'' Id.
 Physically remote isolated wetlands (i.e., wetlands that do not
abut, are separated by more than a natural berm from, are not inundated
by flooding in a typical year from, and do not have a direct hydrologic
surface connection in a typical year to a jurisdictional non-wetland
water) are not adjacent wetlands under the final rule. For example,
impoundments that are formerly adjacent wetlands that are physically
disconnected from other jurisdictional waters in a typical year are not
jurisdictional under the final rule. Additionally, in keeping with the
agencies' longstanding practice, the final rule maintains that wetlands
can be jurisdictional only if they are adjacent to the territorial seas
or a traditional navigable water, tributary, lake, pond or impoundment
of a jurisdictional water. In 1986, the Corps defined ``waters of the
United States'' as including ``wetlands adjacent to [other
jurisdictional] waters (other than waters that are themselves
adjacent),'' 51 FR 41250, meaning that wetlands obtain jurisdictional
status under the CWA by virtue of their adjacency to traditional
navigable waters, tributaries, and other actual waters, not by
adjacency to other wetlands.\38\ In 2019, the agencies recodified this
definition of ``waters of the United States.'' 84 FR 56626. Under this
final rule, wetlands cannot be adjacent to other wetlands; they can
only be adjacent to the territorial seas, a traditional navigable
water, a tributary, or a lake, pond, or impoundment of a jurisdictional
water. This holds true regardless of any hydrologic connection between
a distinct wetland (i.e., a wetland delineated with boundaries distinct
from those of an adjacent wetland) and an adjacent wetland when the
distinct wetland is physically separated from the adjacent wetland by
upland or other artificial or natural features. Because the agencies
believe that the final rule's definition of ``adjacent wetlands'' is
clear on the jurisdictional linchpin for adjacency (by tethering
jurisdiction to paragraph (a)(1) through (3) waters), the agencies are
not including the ``other than waters that are themselves adjacent''
provision from the 2019 Rule (and earlier versions) in this final rule.
---------------------------------------------------------------------------
 \38\ The agencies note that at oral argument in Rapanos, Chief
Justice Roberts recognized this principle, stating that the 1986
definition ``covers wetlands adjacent to waters other than waters
that are themselves wetlands,'' and ``the Corps says we're not going
to reach the wetland that is adjacent to another wetland.''
Transcript of Oral Argument at 45, 47, Rapanos v. United States and
Carabell v. United States, 547 U.S. 715 (2006) (Nos. 04-1034, 04-
1384). The Chief Justice added that this ``suggests that even the
Corps recognized that at some point you've got to say stop because
logically any drop of water anywhere is going to have some sort of
connection through drainage. And they're stopping there, and I
wonder if we ought to take that same instinct that you see in [the
wetlands definition] and apply it to your definition of tributary
and say, at some point, the definition of tributary has to have an
end. Otherwise, you're going to go and reach too far, beyond what
Congress reasonably intended.'' Id. at 46.
---------------------------------------------------------------------------
B. Territorial Seas and Traditional Navigable Waters
1. What are the agencies finalizing?
 The agencies are making no substantive textual changes to the
longstanding inclusion of traditional navigable waters and the
territorial seas in the definition of ``waters of the United States.''
The agencies are finalizing this portion of the rule as proposed, with
slight modifications discussed below. The final rule maintains these
categories of ``waters of the United States'' but consolidates them
into a single paragraph in the regulatory text.
 Many commenters supported the retention of the agencies'
longstanding foundational category of CWA jurisdiction, unchanged from
previous regulatory text. They stated that the category was well
understood, and its application guided by a developed body of case law.
Most commenters supported integrating territorial seas into a single
category with traditional navigable waters, agreeing with the agencies
that it helped streamline the regulatory text, but some requested
clarifications to maintain the distinction between the two types of
waters. Some commenters requested that the agencies modify the test for
traditional navigable waters by clarifying that such waters must be
used to ``transport commerce'' rather than simply being ``used'' for or
susceptible to ``use'' in interstate or foreign commerce, reflecting
the terminology used by Congress in section 404(g) of the CWA.
Responding to the agencies' request for comment on Appendix D, several
commenters requested that the agencies eliminate or modify Appendix D
to the U.S. Army Corps of Engineers Jurisdictional Determination Form
Instructional Guidebook (hereinafter, ``Appendix D''),\39\ stating that
Appendix D is confusing, overstates the agencies' authority under
existing case law, and allows the agencies to regulate virtually any
isolated water by misapplying the established judicial tests for
navigability under the CWA. Other commenters suggested the agencies
retain Appendix D as useful field guidance and to avoid
[[Page 22281]]
confusion associated with any changes in the agencies' approach to
traditional navigable water determinations.
---------------------------------------------------------------------------
 \39\ U.S. Army Corps of Engineers Jurisdictional Determination
Form Instructional Guidebook, available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2316. The agencies note that Appendix D is sometimes referred to as
``Appendix D to the Rapanos Guidance'' and was inadvertently
referred to as such in the preamble to the proposed rule. The
appendix actually resides as an attachment to the Jurisdictional
Determination Form Instructional Guidebook that was published in
2007 concurrently with the 2007 Rapanos Guidance. The Rapanos
Guidance was later undated in 2008, but Appendix D has remained
unchanged since 2007. Appendix D notes (at page 1) that ``EPA and
the Corps are providing this guidance on determining whether a water
is a `traditional navigable water' for purposes of the Rapanos
Guidance, the Clean Water Act (CWA), and the agencies' CWA
implementing regulations.'' This sentence is what is often used to
link the Rapanos Guidance to Appendix D, as the two were intended to
operate in tandem, with other agency resources, to assist in guiding
field implementation of CWA jurisdictional determinations.
---------------------------------------------------------------------------
 The agencies have considered all of the public comments received
addressing these topics and are finalizing paragraph (a)(1) as
proposed, with slight modifications to address questions regarding the
inclusion of the territorial seas within a single category with
traditional navigable waters. The agencies are not modifying the
definition of ``traditional navigable waters'' as it has existed in
regulatory text for decades. As discussed in Section II.G, when this
final rule becomes effective, certain agency guidance documents,
memoranda, and materials (e.g., the 2003 SWANCC Guidance and 2008
Rapanos Guidance) will be rendered inoperative because they will no
longer be necessary or material, and they may in fact create confusion
as the agencies implement this final rule. However, because the
agencies have not modified the definition of ``traditional navigable
waters,'' the agencies are retaining Appendix D to help inform
implementation of that provision of this final rule, as discussed
further in Section III.B.2.
2. Summary of Final Rule Rationale and Public Comment
 The final rule defines ``waters of the United States'' to encompass
traditional navigable waters and the territorial seas. The agencies'
existing definition of ``waters of the United States'' includes 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. See, e.g., 33
CFR 328.3(a)(1). This paragraph of the 2019 Rule (and previous
regulations) encompasses waters that are often referred to as waters
more traditionally understood as navigable or ``traditional navigable
waters.'' A separate paragraph of the 2019 Rule (and previous
regulations) lists the territorial seas as jurisdictional. See 33 CFR
328.3(a)(6). To streamline and simplify the definition of ``waters of
the United States,'' the agencies are finalizing the rule as proposed
to include both traditional navigable waters and the territorial seas
into a single paragraph of jurisdictional waters. The final rule makes
no other substantive changes to these historically regulated categories
of waters.
 The agencies note that the term ``territorial seas'' is defined in
CWA section 502(8), 33 U.S.C. 1362(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.'' The agencies did not propose including
this definition in the rule because it is already defined by statute
and are not including the definition or any further interpretation in
the final rule.
 In this final rule, the agencies are streamlining the regulation so
that the first category of jurisdictional waters includes both
traditional navigable waters and the territorial seas. Most commenters
on this topic agreed with the proposal to combine the territorial seas
and traditional navigable waters into one paragraph of the regulation,
stating that it would streamline and simplify the definition of
``waters of the United States,'' and makes practical sense since the
jurisdictional status of other categories of waters relies on their
surface water connection to either a traditional navigable water or the
territorial seas.
 In the proposed rule, the agencies included the territorial seas as
a type of traditional navigable water because the agencies had not
identified an instance in which a territorial sea would not also be
considered traditionally navigable and thus proposed that the broader
term should suffice. A few commenters expressed concern that the
proposed rule implied that the definition of ``waters of the United
States'' included only the portions of the territorial seas that are
navigable and capable of use in interstate or foreign commerce. The
agencies did not intend to exclude any portion of the territorial seas
as the term is defined in CWA section 502(8), 33 U.S.C. 1362(8). To
avoid any confusion, the agencies have made minor modifications to the
proposed rule text to further clarify that this category of
foundational waters includes both traditional navigable waters and the
territorial seas. The final rule states that the category of ``waters
of the United States'' defined in paragraph (a)(1) includes ``the
territorial seas, and water which are currently used, or were used in
the past, or may be susceptible to use in interstate or foreign
commerce, including waters which are subject to the ebb and flow of the
tide.''
 The agencies have not changed their interpretation of traditional
navigable waters in this final rule, and the agencies are retaining
Appendix D to help inform implementation of this provision with
additional clarification in this notice in response to comments. As
discussed in Section II.E, the definition of navigable-in-fact waters
originates with the Supreme Court's decision in The Daniel Ball, 77
U.S. (10 Wall.) 557 (1870). In that case, the Supreme Court stated:
 Those rivers must be regarded as public navigable rivers in law
which are navigable in fact. And they are navigable in fact when
they are used, or are susceptible of being used, in their ordinary
condition, as highways for commerce, over which trade and travel are
or may be conducted in the customary modes of trade and travel on
water.
 Id. at 563. As explained by the Supreme Court in 2012, ``[t]he
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, LLC
v. Montana, 565 U.S. 576, 592 (2012). ``With respect to the federal
commerce power, the inquiry regarding navigation historically focused
on interstate commerce.'' Id. at 593. The Supreme Court further
explained that, ``of course, the commerce power extends beyond
navigation'' and cautioned ``that the test for navigability is not
applied the same way'' in all cases. Id. at 592-93; see also Kaiser
Aetna v. United States, 444 U.S. 164, 171 (1979) (``[A]ny reliance upon
judicial precedent [in this area] must be predicated upon careful
appraisal of the purpose for which the concept of navigability was
invoked in a particular case.'' (internal quotation marks, citation
omitted, and emphasis in original)). But generally, navigability for
purposes of federal regulatory authority under the federal commerce
power encompasses waters that were ``once navigable but are no
longer,'' PPL Montana, 565 U.S.at 592 (citing Economy Light & Power Co.
v. United States, 256 U.S. 113, 123-24 (1921)), ``waters that only
recently have become navigable,'' id. (citing Philadelphia Co. v.
Stimson, 223 U.S. 605, 634-35 (1912)), and waters that ``are not
navigable and never have been but may become so by reasonable
improvements,'' id. at 592-93 (citing United States v. Appalachian
Elec. Power Co., 311 U.S. 377, 407-08 (1940)). The agencies note that
this summary articulated by the Supreme Court in 2012 generally
reflects the basic structure of the longstanding jurisdictional test
for ``traditional navigable waters'' retained in paragraph (a)(1) of
the final rule.
 Many commenters expressed support for the agencies' decision to
retain the existing regulatory text describing traditional navigable
waters. These
[[Page 22282]]
commenters stated that the existing text is clear, concise,
predictable, and well understood by the public. Other commenters
expressed concern about implementation of the regulation and guidance
and suggested modifications to the regulation. Some commenters
suggested clarifying that traditional navigable waters must be used to
``transport commerce,'' as that is the phrase Congress used to describe
the waters over which the Corps retains permitting authority when
States and Tribes assume CWA section 404 permitting. See 33 U.S.C.
1344(g). As discussed in Section II.E, and consistent with a technical
advisory committee report submitted to EPA as part of an effort to
modernize the section 404(g) assumption process (see n.28), section
404(g) refers to RHA section 10 waters. Some commenters recommended
that the agencies adopt the RHA section 10 definition and the two-part
legal test established by The Daniel Ball for ``navigable waters of the
United States'' as the test for ``traditional navigable waters'' for
purposes of implementing the term ``waters of the United States'' under
the CWA. That test requires first that a water be navigable-in-fact,
and second that commerce be transported across State or foreign lines
on those waters. The Daniel Ball, 77 U.S. (10 Wall.) at 563.
 The Supreme Court has not spoken directly to the precise meaning of
the phrase ``traditional navigable waters'' as that term applies in the
CWA context, but it has stated that the statutory ``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.'' SWANCC, 531 U.S. at 172. In the agencies'
view, the Supreme Court has therefore signaled an acceptance of the
first prong of The Daniel Ball test. Whether the second prong applies
in full to the administrative definition of ``traditional navigable
waters'' is less clear, but the legislative history suggests that
Congress had in mind a more expanded notion of interstate commerce when
enacting the CWA, including overland links to commercial navigation on
navigable-in-fact waters.\40\ As described in Section II.E, the Supreme
Court has stated that nothing in the legislative history of the Act
suggests ``that Congress intended to exert anything more than its
commerce power over navigation.'' SWANCC, 531 U.S. at 168 & n.3. The
agencies therefore are not modifying the longstanding regulatory text
for traditional navigable waters to specifically align it with the RHA
test for jurisdiction, as some commenters suggested.
---------------------------------------------------------------------------
 \40\ See Section II.E for additional discussion of the complex
legislative history on this topic, as well as the detailed
discussion of the same in the Albrecht & Nickelsburg article cited
in note 25.
---------------------------------------------------------------------------
 The agencies acknowledge that some commenters suggested that
Appendix D as-applied in certain circumstances has led to confusion.
For example, some commenters expressed concern that Appendix D could be
read to support a conclusion that any water that can float a boat, even
very shallow draft vessels like canoes and kayaks, is by definition
``susceptible'' to use in interstate commerce and therefore may be
deemed a traditional navigable water. The agencies believe that this
interpretation is inconsistent with the cases summarized in Appendix D
and sweeps too broadly. For example, whether a water is susceptible to
use in interstate commerce requires more than simply being able to
float a boat to establish jurisdiction over navigable-in-fact waters
under paragraph (a)(1); it requires evidence of physical capacity for
commercial navigation and that it was, is, or actually could be used
for that purpose. See, e.g., Appendix D (citing The Montello, 87 U.S.
430, 441-42 (1874); United States v. Holt State Bank, 270 U.S. 49, 56
(1926); United States v. Utah, 283 U.S. 64 (1931); United States v.
Appalachian Elec. Power Co., 311 U.S. 377, 416 (1940)).
 Other commenters provided examples of traditional navigable water
determinations about which the commenters asserted that the capacity to
float a boat in a water that is near an interstate highway was deemed
sufficient to make a traditional navigable water determination under
the paragraph (a)(1) standard. This interpretation is inconsistent with
the applicable case law, including the cases discussed in Appendix D.
Simply driving across a State line and using a waterbody, or having the
potential to use a waterbody, is similar to the theory of jurisdiction
that the Supreme Court specifically rejected in SWANCC. One of the
arguments raised in support of the ``Migratory Bird Rule'' for CWA
jurisdiction was that individuals cross State lines and engage in
commercial activity to hunt or observe migratory birds that use
isolated waters as habitat. See SWANCC, 531 U.S. at 166; id. at 195 &
n.17 (Stevens, J., dissenting). The SWANCC Court rejected this
interpretation of CWA jurisdiction because it raised ``significant
constitutional questions'' that would require the agencies to
``evaluate the precise object or activity that, in the aggregate,
substantially affects interstate commerce.'' Id. at 173-74. The
``substantial effects'' test is the most expansive of the three primary
bases for exercising congressional authority under the Commerce Clause
articulated by the Supreme Court in United States v. Lopez, 514 U.S.
549, 558-59 (1995). This application of the ``substantial effects''
test to assert CWA jurisdiction over waters beyond those more
traditionally understood as navigable was not intended by Appendix D
and has been rejected by the SWANCC Court because it was inconsistent
with Congress' intent to exercise its more traditional ``commerce power
over navigation.'' SWANCC, 531 U.S. at 173 & n.8. Thus, the legal
principles summarized in Appendix D were not intended to endorse, and
should not be interpreted as endorsing, the application of the
``substantial effects'' test to CWA jurisdiction, or otherwise
suggesting that the mere capacity to float a boat makes a waterbody
susceptible to commercial navigation.
 The agencies intend to update their guidance materials, if and as
necessary, as the agencies begin to implement the revised tests for
jurisdiction established by the final rule, both initially and as the
agencies gain field experience to address implementation questions that
may arise. As part of that process, the agencies will continue to
evaluate prior guidance on how to apply established case law principles
to traditional navigable water determinations. The agencies will also
implement field elevation procedures should difficult legal questions
arise, including requiring such interpretations to be reviewed by
senior legal staff at each of the agencies' respective headquarters.
Implementation of this section of the traditional navigable waters
provision of paragraph (a)(1) in the final rule will be case-specific,
as it has always been. This case-specific analysis will include
relevant portions of EPA and Corps regulations, prior determinations by
the Corps and by the federal courts, and case law. Should the agencies
determine that additional, more formal guidance on traditional
navigable waters is warranted, the agencies will develop any such
guidance in compliance with Executive Order 13891, and with any
applicable public participation requirements.
C. Interstate Waters
1. What are the agencies finalizing?
 Consistent with the proposal, this final rule removes interstate
waters, including interstate wetlands, as a separate category of
``waters of the
[[Page 22283]]
United States.'' The agencies are finalizing this aspect of the
proposal to more closely align the regulatory definition with the
constitutional and statutory authorities reflected in the CWA and
judicial interpretations of the term ``navigable waters,'' while
balancing the statute's objective to restore and maintain the integrity
of the nation's waters and its policy directives to preserve and
protect the rights and responsibilities of the States.
 Many commenters supported the removal of interstate waters and
wetlands as an independent category of ``waters of the United States.''
Those commenters stated that such a category was not authorized by the
CWA and that, as proposed by the agencies, waters must be connected to
traditional navigable waters to be jurisdictional under the CWA.
Commenters also stated that interstate waters and wetlands that
actually fall within the scope of CWA jurisdiction would be covered by
the other categories of waters as proposed. Other commenters opposed
removing interstate waters as an independent jurisdictional category.
Those commenters stated that any water that crosses a State line is by
definition a ``water of the United States.'' The same is true, some
commenters added, for waters that cross tribal boundaries. Additional
commenters added that the proposed rule would arbitrarily narrow the
scope of CWA jurisdiction over ecologically important waters and
recommended that the agencies continue to regulate interstate waters.
Other commenters suggested that the exclusion for ephemeral features,
if finalized, would help balance the inclusion of interstate waters as
a category.
 The agencies have considered this diverse range of opinions, and
for the reasons discussed below, have concluded that the best
interpretation of the CWA and its legislative history is to finalize
the regulatory text as proposed, without a separate interstate waters
category. Interstate waters and interstate wetlands remain subject to
CWA jurisdiction under the final rule if they are waters identified in
paragraph (a)(1), (2), (3), or (4) (generally referred to as
``paragraph (a)(1) through (4) waters'' or ``a paragraph (a)(1) through
(4) water'' in this notice).
2. Summary of Final Rule Rationale and Public Comment
 The agencies have evaluated their earlier legal and policy
rationales supporting the inclusion of interstate waters as a separate
category of ``waters of the United States'' and comments on the
proposed rule and are not including this category in the final rule.
The agencies have concluded that the regulation of interstate waters as
a standalone category is based on an overly broad reading of the
original Water Pollution Control Act (WPCA) of 1948 and lacks
foundation in statutory text of the 1972 CWA amendments. The WPCA
stated that the ``pollution of interstate 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), which
endangers the health or welfare of persons in a State other than that
in which the discharge originates, is hereby declared to be a public
nuisance and subject to abatement as herein provided.'' WPCA of 1948,
2(d)(1), (4), 62 Stat. 1155, 1156-57. The statute defined ``interstate
waters'' as ``all rivers, lakes, and other waters that flow across, or
form a part of, State boundaries.'' Id. at 10(e), 62 Stat. 1161.
 In 1961, Congress amended the statute to substitute the term
``interstate or navigable waters'' for ``interstate waters'' in the
statute's enforcement provision while making minor changes to the
definition of ``interstate waters.'' See Public Law 87-88, 75 Stat. 208
(1961). In 1965, Congress again amended the statute to require states
to develop water quality standards for all ``interstate waters'' within
their borders. See Public Law 89-234, 79 Stat. 908 (1965). In 1972,
Congress amended the statute again and selected the term ``navigable
waters'' as the operative term for the major regulatory programs
established by the 1972 amendments, dropping the definition of
``interstate waters'' from the statute. See, e.g., 33 U.S.C. 1362(7)
(defining ``navigable waters'' as ``waters of the United States''). In
doing so, however, Congress allowed States to retain existing water
quality standards for interstate waters developed under the pre-1972
statutory program. See 33 U.S.C. 1313(a).
 The EPA promulgated its first regulatory definition for the term
``waters of the United States'' in 1973. 38 FR 13528 (May 22, 1973). In
that regulation, the EPA administratively determined that ``interstate
waters'' should be a separate category of ``waters of the United
States,'' distinct from the traditional navigable waters category, and
until this final rule the agencies had retained it as a separate
category.
 The agencies previously viewed navigable and interstate waters as
having distinct and separate meanings because Congress in 1961 used
both terms in the statute. The agencies explained their prior
interpretation in part through the doctrine of congressional
acquiescence, in that Congress was aware of the EPA's retention of
``interstate waters'' as a separate category when amending the CWA in
1977 (making no amendments to remove the agencies' regulatory inclusion
of interstate waters), and therefore acquiesced to its inclusion as a
separate category. The agencies have also historically relied on two
Supreme Court cases--Illinois v. City of Milwaukee, 406 U.S. 91 (1972)
and City of Milwaukee v. Illinois, 451 U.S. 304 (1981)--addressing
interstate water pollution to further support their prior
interpretation. In the 1972 case, which was decided prior to the date
of the 1972 CWA amendments, the Supreme Court referred to the two
categories in the disjunctive, implying that the Court viewed the pre-
1972 statutory program as encompassing two separate categories. See
Illinois, 406 U.S. at 102 (``it is federal, not state, law that in the
end controls pollution of interstate or navigable waters'') (emphasis
added). The 1981 case is described further below. The agencies also
have referred to section 303(a) of the CWA as further evidence that
Congress intended ``interstate waters'' to be retained as an
independent category of jurisdictional waters because that provision
authorized water quality standards for ``interstate waters'' developed
following the 1965 amendments to remain in effect, subject to revision
under the new statutory program. A more complete summary of the
agencies' prior legal position with respect to interstate waters was
included in a Technical Support Document prepared in support of the
2015 Rule (``2015 Rule TSD'').\41\ The agencies now conclude that their
prior interpretation is inconsistent with the text and structure of the
CWA.
---------------------------------------------------------------------------
 \41\ U.S. EPA and U.S. Department of the Army. Technical Support
Document for the Clean Water Rule: Definition of Waters of the
United States (May 2015) (Docket ID: EPA-HQ-OW-2011-0880-20869),
available at https://www.regulations.gov/document?D=EPA-HQ-OW-2011-0880-20869.
---------------------------------------------------------------------------
 When Congress enacted the 1972 CWA amendments, it selected the term
``navigable waters'' to frame the scope of federal regulatory
jurisdiction under the Act. Rather than interpreting those amendments
as retaining ``interstate waters'' as a separate and distinct category
of ``waters of the United States,'' the agencies now conclude that a
more natural interpretation of the 1972 amendments is an express
rejection of that independent category, as Congress had before it both
options within the scope of the statute it was modifying. Congress
specifically did not carry that term forward as the operative phrase
for
[[Page 22284]]
federal jurisdiction. Under basic canons of statutory construction, the
agencies begin with the presumption that Congress did so intentionally.
See, e.g., Stone v. INS, 514 U.S. 386, 397 (1995) (``When Congress acts
to amend a statute, we presume it intends its amendment to have real
and substantial effect.'').
 Congressional acquiescence is a doctrine of limited application and
was specifically rejected as a basis for expansive federal jurisdiction
in SWANCC in the context of analyzing the Corps' 1977 regulations.
SWANCC, 531 U.S. at 170-71 (``Although we have recognized congressional
acquiescence to administrative interpretations of a statute in some
situations, we have done so with extreme care.''). The plurality
opinion in Rapanos further elaborated, when also rejecting the notion
that Congress acquiesced to the Corps' 1977 regulations, that
``Congress takes no governmental action except by legislation. What the
dissent refers to as `Congress' deliberate acquiescence' should more
appropriately be called Congress's failure to express any opinion.''
Rapanos, 547 U.S. at 750 (Scalia, J., plurality). The plurality
explained that we cannot know whether Congress' inaction resulted from
their belief that the Corps' regulations were correct, or from other
reasons, such as confidence that courts would correct excesses or
political considerations. See SWANCC, 531 U.S. at 169-70, 178 n.5
(``Absent such overwhelming evidence of acquiescence, we are loath to
replace the plain text and original understanding of a statute with an
amended agency interpretation.''). The agencies now conclude,
consistent with the admonitions of SWANCC and the Rapanos plurality,
that the doctrine of congressional acquiescence is not a sound basis to
guide the agencies' decision regarding the scope of federal
jurisdiction over certain waters in this final rule, particularly as it
applies to interstate waters divorced from any notion of commercial
navigability.
 The legislative history of the 1972 amendments, in fact, supports
the agencies' conclusion that Congress did not consider interstate
waters and navigable waters to be two separate and distinct categories,
and instead referred to terms in the pre-1972 statutory regime
conjunctively as ``interstate navigable waters.'' S. Rep. No. 92-414,
at 2 (1971) (``Each State was required by the 1965 Act to develop
standards for water quality within its boundaries. These standards were
to be applied to all interstate navigable waters flowing through the
State; intrastate waters were not included.'') (emphasis added); id. at
4 (``The setting of water quality standards for interstate navigable
waters . . . is the keystone of the present program for control of
water pollution.'') (emphasis added); id. (``The States have first
responsibility for enforcement of their standards. When approved by the
[EPA], however, the standards for interstate navigable waters become
Federal-State standards.'') (emphasis added). In fact, the legislative
history suggests that Congress modified the text of the statute in 1972
in part because the States had narrowly interpreted the phrase
``interstate'' to apply only to interstate navigable waters and had
failed to establish water quality standards for the intrastate
tributaries to such waters. See, e.g., id. at 77 (``The control
strategy of the Act extends to navigable waters . . . . Through a
narrow interpretation of the definition of interstate waters the
implementation [of the] 1965 Act was severely limited.''); 118 Cong.
Rec. 10240 (1972) (the amendment ``expands the coverage of the law to
intrastate, as well as interstate navigable waterways'') (emphasis
added). In 1976, the Supreme Court shared the same view of the pre-1972
statutory scheme: ``Before it was amended in 1972, the Federal Water
Pollution Control Act employed ambient water quality standards
specifying the acceptable levels of pollution in a State's interstate
navigable waters as the primary mechanism in its program for the
control of water pollution.'' EPA v. California, 426 U.S. 200, 202
(1976) (emphasis added) (footnote omitted). This history suggests that
the section 303(a) provision relating to existing water quality
standards for ``interstate waters'' was referring to ``interstate
navigable waters,'' not interstate waters more broadly.
 Neither Supreme Court case previously relied on by the agencies and
discussed in the 2015 Rule TSD addressed the specific question whether
``interstate waters'' and ``navigable waters'' are separate and
distinct categories of jurisdictional waters under the CWA. They
instead addressed interstate water pollution generally, and the water
at issue in those cases was Lake Michigan, an interstate navigable-in-
fact water. The 1981 decision, however, did recognize that the 1972
amendments ``were viewed by Congress as a `total restructuring' and
`complete rewriting' of the existing water pollution legislation
considered in that case.'' Milwaukee, 451 U.S. at 317 (citing
legislative history of the 1972 CWA amendments). This supports the
agencies' conclusion that prior iterations of the statute, referring to
both interstate waters and navigable waters, were replaced with a
completely new program in 1972, not that certain aspects of that
program continued through congressional acquiescence in a later
regulatory determination. The final rule therefore eliminates
``interstate waters'' as a separate category of ``waters of the United
States.''
 By eliminating a separate category for interstate waters, the final
rule adheres to the legal principles discussed in Section II.E by
including within the definition of ``waters of the United States''
traditional navigable waters, the territorial seas, and waters subject
to the ebb and flow of the tide; tributaries to such waters; certain
lakes, ponds, and impoundments of otherwise jurisdictional waters; and
wetlands adjacent to jurisdictional waters. Because the agencies'
authority flows from Congress' use of the term ``navigable waters'' in
the CWA, the agencies lack authority to regulate waters untethered from
that term. Nothing in the legislative history of the 1972 CWA
amendments ``signifies that Congress intended to exert anything more
than its commerce power over navigation.'' SWANCC, 531 U.S. at 168 n.3.
 Therefore, those interstate waters that would satisfy the
definitions in this final rule are jurisdictional; interstate waters
without any surface water connection to traditional navigable waters or
the territorial seas are not within the agencies' authority under the
CWA and are more appropriately regulated by the States and Tribes under
their sovereign authorities.
 The agencies' rationale is supported by the U.S. District Court for
the Southern District of Georgia's remand order. Georgia v. Wheeler,
No. 2:15-cv-00079, 2019 WL 3949922 (S.D. Ga. Aug. 21, 2019). There, the
court directly addressed the 2015 Rule's assertion of authority over
all interstate waters, including nonnavigable interstate waters. Id. at
*10-13. The court found that ``the inclusion of all interstate waters
in the definition of `waters of the United States,' regardless of
navigability, extends the Agencies' jurisdiction beyond the scope of
the CWA because it reads the term navigability out of the CWA.'' Id. at
*12. The court also found that, because the 2015 Rule would assert
jurisdiction over tributaries, adjacent waters, and case-by-case waters
based on their relationship to non-navigable isolated interstate
waters, it would result in federal jurisdiction over even the most
remote and isolated waters that the Supreme Court held in SWANCC are
beyond the
[[Page 22285]]
reach of the CWA. Id. at *13. The agencies agree with the court's
analysis and conclusion.
 This final rule marks a shift away from prior agency positions. The
agencies received public comment that the proposal had failed to
analyze potential impacts resulting from the removal of ``interstate
waters'' as a separate category, but as noted in the preamble to the
proposed rule, the agencies are not aware of any database that
identifies the jurisdictional status of interstate waters based solely
on the fact that they cross state lines, or any other resource that
would identify these waters. The agencies therefore lack the ability to
perform a comparative analysis with any precision. Some commenters
provided examples of interstate waters that may lose jurisdictional
status if the separate category is eliminated; however, the Corps' ORM2
database does not contain any jurisdictional determinations based
solely on a water's status as an interstate water. Since issuance of
the Rapanos Guidance, the Corps has not tracked this category
separately for approved jurisdictional determinations conducted under
the Guidance in ORM2.
 The agencies requested comment on the rationales in favor of and
opposed to a separate jurisdictional category for ``interstate
waters.'' Some commenters supported the proposal to remove ``interstate
waters'' as a separate category, noting that there is no statutory or
constitutional basis to regulate interstate waters that would not
otherwise be jurisdictional and suggesting that the agencies lacked the
authority to include a separate ``interstate'' category in earlier
versions of the regulations. Other commenters opposed the proposal,
asserting that the text and structure of the CWA, legislative history,
and prior court cases, including Justice Scalia's discussion in
Rapanos, demonstrate that the CWA applies to interstate waters
regardless of navigability. The agencies considered these comments and,
for the reasons explained above, conclude that the final rule most
closely aligns with the agencies' constitutional and statutory
authorities reflected in the CWA and relevant judicial interpretations
of the term ``navigable waters'' and the legislative history of the
CWA, while balancing the statute's objective to restore and maintain
the integrity of the nation's waters and its policy directives to
preserve and protect the rights and responsibilities of the States.
 Some commenters stated that the agencies did not provide sufficient
rationale for deviating from their prior analysis and interpretation,
as provided in the 2015 Rule TSD. The agencies disagree, as the
proposal clearly identified independent reasons questioning the
validity of the agencies' prior interpretation. The agencies' 2015 Rule
TSD, for example, included three primary arguments supporting the prior
interpretation: First, the language, structure, and history of the CWA
demonstrate that Congress intended to include interstate waters in
addition to navigable waters; second, the Supreme Court decisions in
Rapanos and SWANCC did not constrain CWA jurisdiction over isolated,
nonnavigable, interstate waters; and third, Supreme Court precedent
supports jurisdiction over interstate waters, regardless of
navigability. These arguments are addressed in the proposal and in
earlier sections of this notice, but the agencies provide additional
detail to respond to comments received as follows.
 The 2015 Rule TSD analyzed two Supreme Court decisions to support
its conclusion that interstate waters should be a separate category of
jurisdiction under the CWA. The first decision was issued in 1972, just
prior to the 1972 CWA amendments, and concluded that federal common law
was appropriate to resolve a cross-border water pollution dispute among
states where existing statutes did not address the dispute. Illinois,
406 U.S. 91. The Court found that where ``no fixed rules'' govern
cross-boundary pollution disputes, ``these will be equity suits in
which the informed judgment of the chancellor will largely govern.''
Id. at 107-08.
 The second decision was issued in 1981, and it analyzed the effect
of the 1972 amendments on a federal common law claim concerning the
same cross-border water pollution dispute that was presented the 1972
case. City of Milwaukee, 451 U.S. 304. In that case, the Court
acknowledged the 1972 amendments and noted that ``[t]he establishment
of such a self-consciously comprehensive program by Congress, which
certainly did not exist when Illinois v. Milwaukee was decided,
strongly suggests that there is no room for courts to attempt to
improve on that program with federal common law.'' Id. at 319 (emphasis
added).
 Contrary to the assertions in the 2015 Rule TSD, however, the Court
did not conclude that the CWA occupies the field with regard to all
interstate waters.\42\ Instead, the Court considered the facts of the
case before it--whether NPDES permits issued by an authorized State in
compliance with the CWA could be modified or augmented by federal
common law claims brought by a downstream State. Focusing on
respondents' claims that discharges from the facilities were causing a
public nuisance, the Court observed that, ``the action of Congress in
supplanting the federal common law is perhaps clearest when the
question of effluent limitations for discharges from the two treatment
plants is considered.'' City of Milwaukee, 451 U.S. at 319-20. The
Court identified the numerous provisions of the permits that addressed
discharges and overflows from the facilities, and the State-initiated
enforcement action contemplated by the CWA, and concluded that
``[t]here is no `interstice' here to be filled by federal common law:
Overflows are covered by the Act and have been addressed by the
regulatory regime established by the Act. Although a Federal court may
disagree with the regulatory approach taken by the agency . . . such
disagreement alone is no basis for the creation of federal common
law.'' Id. at 323.
---------------------------------------------------------------------------
 \42\ See U.S. EPA and Department of the Army, Technical Support
Document of the EPA-Army Clean Water Rule at 210 (May 20, 2015)
(``2015 Rule TSD'') (Docket ID: EPA-HQ-OW-2011-0880-20869) available
at https://www.regulations.gov/document?D=EPA-HQ-OW-2011-0880-20869.
(``In City of Milwaukee, the Court found that the CWA was the
`comprehensive regulatory program' that `occupied the field' (451
U.S. 317) with regard to interstate water pollution, eliminating the
basis for an independent common law of nuisance to address
interstate water pollution.''). The 2015 Rule TSD also asserts that
the Court ``expressly overruled'' its decision in Illinois; however,
a more precise statement would be that the Court found no federal
common law remedy available ``at least so far as concerns the claims
of respondents'' because Congress occupied the field with a federal
regulatory program that establishes effluent limits and other
specific requirements that supersede the ``often vague and
indeterminate nuisance concepts and maxims of equity
jurisprudence.'' City of Milwaukee, 451 U.S. at 317 (emphasis
added).
---------------------------------------------------------------------------
 The Court also noted that in its 1972 decision, the Court was
concerned that the downstream State ``did not have any forum in which
to protect its interests unless federal common law were created,'' City
of Milwaukee, 541 U.S. at 325, but that the NPDES permitting provisions
of the 1972 amendments ``provided ample opportunity for a State
affected by decisions of a neighboring State's permit-granting agency
to seek redress.'' Id. at 325-26 (identifying the CWA requirement to
provide notice to affected States and opportunity to comment and
request public hearings, the Wisconsin law that provides the same,
affected States' opportunity under the CWA to petition the EPA to
object to a NPDES permit, and noting that respondents did not take
advantage of these provisions). The case therefore presented a dispute
between States concerning NPDES permits lawfully issued for discharges
into an otherwise
[[Page 22286]]
navigable water--Lake Michigan. The Supreme Court did not consider
disputes outside of the NPDES permit program or those concerning non-
navigable interstate waters, and the Court did not broadly conclude
that the CWA occupies the field of all interstate water pollution.\43\
All it had before it was the CWA, and as discussed in Section II,
Congress chose not to exercise its full powers under the Commerce
Clause when enacting the 1972 amendments. Congress specifically
recognized that there are other land and water resources that are more
appropriately regulated by the States and Tribes under their sovereign
authorities. Field preemption cannot extend beyond the field. Hines v.
Davidowitz, 312 U.S. 52, 78-79 (1941) (``[e]very Act of Congress
occupies some field, but we must know the boundaries of that field
before we can say that it has precluded a state from the exercise of
any power reserved to it by the Constitution''); see also Gonzales v.
Oregon, 546 U.S. 243, 275 (2006); Medtronic, Inc. v. Lohr, 518 U.S.
470, 475 (1996); Metropolitan Life Ins. Co. v. Massachusetts, 471 U.S.
724, 756 (1985)).
---------------------------------------------------------------------------
 \43\ In a footnote, the 2015 Rule TSD identifies two other
Supreme Court decisions and concludes that ``[n]othing in either
decision limits the applicability of the CWA to interstate water
pollution disputes involving navigable interstate waters or
interstate waters connected to navigable waters.'' 2015 Rule TSD at
211 n.16 (referencing International Paper v. Ouellette, 479 U.S. 481
(1987), and Arkansas v. Oklahoma, 503 U.S. 91 (1992)). Similar to
the facts of City of Milwaukee, both of these cases addressed
disputes that arose in the CWA's NPDES permitting context for waters
that would otherwise be jurisdictional--Lake Champlain and the
Illinois River. In neither case was the Court asked to consider
whether or how the CWA may apply to non-navigable interstate waters,
and these cases do not provide useful context or precedent on that
issue. The 2015 Rule TSD similarly concluded that neither SWANCC nor
Rapanos addressed or limited CWA jurisdiction over non-navigable
interstate waters. See Section II.E of this notice for the agencies'
detailed analysis of the SWANCC and Rapanos decisions.
---------------------------------------------------------------------------
 The agencies also requested comment on an alternative approach that
would retain ``interstate waters'' as a separate category, reflecting
longstanding agency practice, and whether the term ``interstate''
should be interpreted as crossing between States, between States and
tribal lands, between States and/or tribal lands and foreign countries,
or other formulations. Some commenters opposed this alternative
approach, stating that the agencies lacked the authority to codify or
implement it. Other commenters supported retaining ``interstate
waters'' as a separate category and expressed concern that removing it
would eliminate the EPA's role as a co-regulator in cross-boundary
disputes over water quality.
 The CWA provides two opportunities for the EPA to mediate disputes
among States: The section 401(a)(2) neighboring jurisdiction
notification provisions for federally permitted projects that may
discharge to navigable waters and the section 319(g) provisions
allowing the EPA to convene an interstate management conference to
address cross-boundary nonpoint pollution in navigable waters. In the
past, these provisions have been invoked infrequently by States, and
the agencies do not expect a significant increase in cross-boundary
disputes as a result of this rulemaking. In addition, the EPA can
address concerns of States whose waters may be affected by the issuance
of a permit in another State through the permit objection process
pursuant to CWA sections 402(b)(5), 402(d)(d), and 40 CFR 123.44(c)(2).
As demonstrated in City of Milwaukee, if a cross-boundary dispute is
one that is contemplated and addressed by the CWA, such as the
sufficiency of effluent limits in a NPDES permit, the statute has
occupied the field and federal common law does not provide a remedy.
451 U.S. at 317. However, if a State NPDES permit or a section 401
certification is not required, the EPA does not have a role within the
CWA permitting framework to address cross-boundary disputes; similarly,
if a water is not a ``water of the United States,'' then the EPA's
conference convening authorities under section 319(g) would not apply.
In addition, and as described in the Section II.B of this notice, the
CWA provides the EPA with numerous other authorities to provide
technical assistance to States and Tribes to facilitate the management
of non-jurisdictional waters.\44\
---------------------------------------------------------------------------
 \44\ In addition, the notion that categorical federal regulation
of interstate waters is necessary to end water pollution disputes
between States would call into the question the need for CWA section
103 (``Interstate Cooperation and Uniform Laws''), 33 U.S.C. 1253,
which establishes a framework for the Administrator to encourage
cooperation between States for the prevention and control of
pollution.
---------------------------------------------------------------------------
 Under the current framework, the remedies available for cross-
boundary water pollution disputes over non-jurisdictional waters
depends upon the parties and the issues in the case. As an initial
matter, many State programs regulate more waters than are covered by
the federal definition of ``waters of the United States'' and may have
similar notification provisions in place for States affected by a
State-issued NPDES permit. See e.g., Wis. Stat. 281.33 (authorizing
Wisconsin to issue NPDES permits for all waters of the State); Wis.
Admin. Code. 203.03 (providing notice during the NPDES process to other
agencies, including other States potentially affected by the
discharge). This important fact supports the agencies' conclusion that
all States protect their water resources under State law and many have
the ability and expertise to do so in the absence of federal
regulation, as discussed in more detail in the Resource and
Programmatic Assessment for the final rule. As they do today, 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. See, e.g., Illinois, 406
U.S. at 98-99. 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. See id. at 100, 107-08;
International Paper, 479 U.S. at 497-500.
D. Tributaries
1. What are the agencies finalizing?
 In this final rule, the agencies retain ``tributaries'' as a
category of jurisdictional waters subject to CWA jurisdiction. The
final rule defines ``tributary'' to mean a river, stream, or similar
naturally occurring surface water channel that contributes surface
water flow to the territorial seas or traditional navigable waters
(paragraph (a)(1) waters) in a typical year either directly or through
one or more tributaries (paragraph (a)(2) waters), lakes, ponds, and
impoundments of jurisdictional waters (paragraph (a)(3) waters), or
adjacent wetlands (paragraph (a)(4) waters). A tributary must be
perennial or intermittent in a typical year. The alteration or
relocation of a tributary does not modify its jurisdictional status as
long as it continues to satisfy the flow conditions of this definition.
A tributary does not lose its jurisdictional status if it contributes
surface water flow to a downstream jurisdictional water in a typical
year through a channelized non-jurisdictional surface water feature,
through a subterranean river, through a culvert, dam, tunnel, or
similar artificial feature, or through a debris pile, boulder field, or
similar natural feature.
 As discussed in greater detail in Section III.E, the term
``tributary'' includes a ditch that either relocates a tributary, is
constructed in a tributary, or is constructed in an adjacent wetland as
long as the ditch satisfies the flow conditions of the ``tributary''
definition. A ditch can also be a traditional navigable water if it
meets the
[[Page 22287]]
conditions of that category. The agencies are excluding all other
ditches from the definition of ``waters of the United States,'' other
than those identified in paragraph (a)(1) or (2) and ditches any
portion of which are constructed in an adjacent wetland that lack
perennial or intermittent flow (meaning they do not satisfy the
``tributary'' definition in paragraph (c)(12)) but that develop
wetlands in all or portions of the ditch that satisfy the ``adjacent
wetlands'' definition in paragraph (c)(1). Excluded ditches may be
subject to regulation under State or tribal law and could potentially
be conveyances of discharges of pollutants from ``point sources''
subject to CWA permitting (see 33 U.S.C. 1362(14)) if they convey
pollutants from a discharger to jurisdictional waters.
 Regardless of the name they are given locally (e.g., creek, bayou,
branch, brook, run), or their size (e.g., discharge volume, width,
depth, stream order), waters that meet the definition of ``tributary''
are jurisdictional under this final rule. Surface features that flow
only in direct response to precipitation, such as ephemeral streams,
swales, gullies and rills, are not tributaries. These features lack the
required perennial or intermittent flow to satisfy the ``tributary''
definition and therefore are not jurisdictional. However, such features
may convey surface water flow from an upstream jurisdictional water to
a downstream jurisdictional water without severing jurisdiction of the
tributary.
 The regulatory status of tributaries has evolved over the last
several decades, resulting in confusion for the regulated community and
regulators alike. Some commenters said that all channels on the
landscape that convey water, regardless of flow regime, should be
subject to CWA regulation, including both natural and artificial
channels. Others asserted that Congress intended to regulate only
traditional navigable waters, and navigable tributaries to those
waters. Some would regulate all ditches, while others would exclude all
ditches from CWA jurisdiction. Some stated that all ephemeral washes
should be regulated, while others viewed ephemeral features as more
like land that is wet after it rains. Some would extend jurisdiction to
perennial rivers and streams and cut off jurisdiction for intermittent
or seasonal waters. Others would regulate intermittent waters based on
a minimum number of days of continuous flow, such as 30, 90, or 185.
Even the Supreme Court has struggled with articulating clear principles
governing which tributaries to traditional navigable waters should be
subject to CWA jurisdiction, as evidenced by the fractured opinion in
Rapanos. What is clear from that opinion, however, is that a majority
of the Court believed the agencies' existing standard for tributaries
at that time raised serious questions regarding the scope of the
agencies' authority under the CWA. See Section II.E.2.
 The agencies proposed a definition for ``tributary'' that they
believed respected their statutory and constitutional authorities,
consistent with principles established in Riverside Bayview, SWANCC,
and Rapanos. Many commenters agreed with the proposal, indicating that
it balanced federal authority over the core waters targeted by Congress
under the CWA with waters that are more appropriately regulated solely
by the States and Tribes. Others argued that the proposed ``tributary''
definition regulated too broadly, preferring instead that the agencies
restrict jurisdiction to perennial tributaries only. Others argued that
the agencies failed to regulate ecologically important ephemeral
reaches and cut off jurisdiction to headwater reaches that are
important to the tributary network.
 The agencies have considered all comments received and have crafted
a final regulatory definition of ``tributary'' designed to adhere to
the legal principles articulated in this notice and that provides a
predictable, implementable regulatory framework. The agencies are
finalizing their proposal to regulate perennial and intermittent
tributaries to traditional navigable waters, while excluding ephemeral
streams from CWA jurisdiction as those features are more appropriately
regulated by States and Tribes under their sovereign authorities.
However, the agencies have modified the final rule to reduce the
instances in which natural and artificial features and structures sever
jurisdiction of upstream waters, as discussed in Section III.A.3 and in
more detail below. The agencies conclude that interpreting upstream
waters that contribute surface water flow in a typical year to a
paragraph (a)(1) water to be part of the regulated tributary network
better balances the CWA's objective in section 101(a) with the need to
respect State and tribal authority over land and water resources as
mandated by Congress in section 101(b).
2. Summary of Final Rule Rationale and Public Comment
 The definition of ``tributary'' in the final rule reflects the
authority granted by Congress to regulate navigable waters and the
interconnected nature of the tributary system, as well as the ordinary
meaning of the term ``waters.'' In addition, the agencies are adhering
to their constitutional and statutory authority regarding the role of
the Federal government and limits on its authority to regulate the use
of land and waters within State and tribal boundaries, and their
intention to establish a clear and easily implementable definition. The
definition of ``tributary'' in the final rule sets a boundary on the
scope of the regulation to ensure that it is consistent with the role
of the Federal government under the Constitution and the CWA. As the
Supreme Court recognizes, States traditionally exercise ``primary power
over land and water use,'' SWANCC, 531 U.S. at 174. The Federal
government should avoid pressing against the outer limits of its
authority when doing so would infringe upon the traditional rights and
responsibilities of States to manage their own waters. See id. at 172-
73 and supra Section II.E.
 Under this final rule, a tributary must be perennial or
intermittent, and it must contribute surface water flow in a typical
year to a traditional navigable water or territorial sea directly or
through one or more waters identified in paragraph (a)(2), (3), or (4)
(generally referred to as ``paragraph (a)(2) through (4) waters'' or
``a paragraph (a)(2) through (4) water'' in this notice), or through
one or more of the features described in Section III.A.3. The
``tributary'' category includes waters that, due to their relatively
permanent flow classifications and their contribution of surface water
flow to paragraph (a)(1) waters, are appropriately regulated under the
Commerce Clause powers that Congress exercised when enacting the CWA.
The agencies have concluded that their regulatory authority under the
CWA and Supreme Court precedent is most appropriately interpreted to
encompass the perennial and intermittent flow classifications provided
in the definition of ``tributary,'' and that this approach also
balances the regulation of the Federal government with the authority of
States and Tribes to more appropriately regulate certain waters within
their jurisdiction, such as ephemeral streams. The agencies have also
concluded that this definition effectively furthers both the objective
of the Act to ``restore and maintain the chemical, physical, and
biological integrity of the nation's waters'' and 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 for the development and
[[Page 22288]]
use (including restoration, preservation, and enhancement) of land and
water resources . . . .'' 33 U.S.C. 1251(b); see also Rapanos, 547 U.S.
at 737 (Scalia, J., plurality). The agencies' approach to defining
``tributary'' is also intended to ensure that federal regulatory
jurisdiction does not intrude upon State, tribal, and local control of
land and water use decisions. See Rapanos, 547 U.S. at 738 (Scalia, J.,
plurality) (``Regulation of land use, as through the issuance of the
development permits . . . is a quintessential state and local
power.''). With this final definition, the agencies seek to avoid
``impairing or in any manner affecting any right or jurisdiction of the
States with respect to the waters (including boundary waters) of such
States.'' 33 U.S.C. 1370.
 A clear regulatory line between jurisdictional and excluded waters
has the additional benefit of being less complicated than prior
regulatory regimes that required a case-specific significant nexus
analysis. Ephemeral features, such as dry washes and arroyos, that lack
the perennial or intermittent flow necessary to satisfy the
``tributary'' definition under this final rule are excluded from the
definition. Although the agencies are not regulating features that flow
only in direct response to precipitation, certain ephemeral features
can convey surface water flow that is sufficient to maintain the
jurisdictional status of the upstream tributary reach, as discussed in
Section III.A.3. States and Tribes may also address ephemeral features
as ``waters of the State'' or ``waters of the Tribe'' under their own
laws to the extent they deem appropriate, as envisioned under section
101(b) of the CWA. In addition, an ephemeral feature may convey a
discharge of pollutants from a point source to a water of the United
States. See Rapanos, 547 U.S. at 743-44 (Scalia, J., plurality).
 Some commenters stated that the agencies' proposal for tributaries
is not supported by science and is inconsistent with the CWA and
judicial precedent. The agencies disagree. As discussed in the preamble
to the proposed rule, the agencies relied on the available science to
help inform where to draw the line of federal jurisdiction over
tributaries, consistent with their statutory authorities. See 84 FR
4175 (``This proposed definition [of tributary] is also informed by the
science.'') As noted in that preamble, while the SAB found that the
draft Connectivity Report ``provides strong scientific support for the
conclusion that ephemeral, intermittent, and perennial streams exert a
strong influence on the character and functioning of downstream waters
and that tributary streams are connected to downstream waters,'' the
SAB stressed that ``the EPA should recognize that there is a gradient
of connectivity.'' SAB Review at 3. The SAB recommended that ``the
interpretation of connectivity be revised to reflect a gradient
approach that recognizes variation in the frequency, duration,
magnitude, predictability, and consequences of physical, chemical, and
biological connections.'' Id. at 2 (emphasis added). To describe the
``connectivity gradient'' and the probability that impacts occurring
along the gradient will be transmitted downstream, the SAB developed a
figure as part of its review of the Draft Connectivity Report. See id.
at 54 figure 3. The figure illustrates the connectivity gradient and
potential consequences between perennial, intermittent, and ephemeral
streams and downstream waters and depicts a decreased ``probability
that changes . . . will be transmitted to downstream waters'' at flow
regimes less than perennial and intermittent. Id. While the SAB stated
that ``at sufficiently large spatial and temporal scales, all waters
and wetlands are connected,'' it found that ``[m]ore important are the
degree of connection (e.g., frequency, magnitude, timing, duration) and
the extent to which those connections affect the chemical, physical,
and biological integrity of downstream waters.'' Id. at 17.
 The SAB, however, recognized that ``[t]he Report is a science, not
policy, document that was written to summarize the current
understanding of connectivity or isolation of streams and wetlands
relative to large water bodies such as rivers, lakes, estuaries, and
oceans.'' id. at 2. ``The SAB also recommended that the agencies
clarify in the preamble to the final rule that `significant nexus' is a
legal term, not a scientific one.'' 80 FR 37065. And in issuing the
2015 Rule, the agencies stated, ``the science does not provide a
precise point along the continuum at which waters provide only
speculative or insubstantial functions to downstream waters.'' Id. at
37090. Thus, the agencies use the Connectivity Report to inform certain
aspects of the revised definition of ``waters of the United States,''
such as recognizing the ``connectivity gradient'' and potential
consequences between perennial, intermittent, and ephemeral streams and
downstream waters within a tributary system. The ``tributary''
definition that the agencies are finalizing, which takes into
consideration the connectivity gradient, ``rests upon a reasonable
inference of ecological interconnection'' between those tributaries and
paragraph (a)(1) waters. 547 U.S. at 780 (Kennedy, J., concurring in
the judgment). The agencies acknowledge that science alone cannot
dictate where to draw the line between Federal and State waters, as
those are legal distinctions that have been established within the
overall framework and construct of the CWA.
 The agencies also relied on scientific principles, as appropriate
and within the agencies' statutory limits, to inform several other
aspects of this final rule, including, for example, how the agencies
define the flow classifications (perennial, intermittent, ephemeral)
used throughout the regulation, the incorporation of inundation and
flooding to create surface water connections, and the use of the
typical year concept that relies upon a large body of precipitation and
other climatic data to inform what may be within a normal range for a
particular geographic region. The agencies will also rely on science to
implement the final rule, such as with the development of tools and
scientific-based approaches to identify flow classification and typical
year conditions.
 Thus, contrary to the assertions of some commenters, the agencies'
decisions in support of this final rule have been informed by science.
The agencies therefore agree with other commenters who stated that the
agencies appropriately balanced science, policy, and the law when
crafting the proposed rule. But to be clear, as discussed in the
preamble to the proposed rule, 84 FR 4176, and in Section II.E of this
notice, science cannot dictate where to draw the line between Federal
and State or tribal waters, as those are legal distinctions that have
been established within the overall framework and construct of the CWA.
The definition of ``waters of the United States'' must be grounded in a
legal analysis of the limits on CWA jurisdiction reflected in the
statute and Supreme Court guidance.
 By defining perennial and intermittent tributaries of traditional
navigable waters as jurisdictional and ephemeral features as non-
jurisdictional, the agencies balance Congress' intent to interpret the
term ``navigable waters'' more broadly than the classical understanding
of that term, see Riverside Bayview, 474 U.S. at 133, with the fact
that nothing in the legislative history of the Act ``signifies that
Congress intended to exert anything more than its commerce power over
navigation.'' SWANCC, 531 U.S. at 168 n.3. The final rule's definition
of ``tributary'' is also consistent with the Rapanos plurality's
position that `` `the
[[Page 22289]]
waters of the United States' include only relatively permanent,
standing, or flowing bodies of waters . . . as opposed to ordinarily
dry channels . . . or ephemeral flows of water.'' Rapanos, 547 U.S. at
732-33 see also id. at 736 n.7 (``[R]elatively continuous flow is a
necessary condition for qualification as a `water,' not an adequate
condition'' (emphasis in original)). Perennial waters, by definition,
are permanent. And while the plurality did note that waters of the
United States do not include ``ordinarily dry channels through which
water occasionally or intermittently flows,'' id. at 733, the plurality
would ``not necessarily exclude 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); compare id. at 770
(Kennedy, J., concurring in the judgment) (``an intermittent flow can
constitute a stream . . . while it is flowing . . . [i]t follows that
the Corps can reasonably interpret the Act to cover the paths of such
impermanent streams''). The agencies note that intermittent waters may
occur seasonally, for example, during times when groundwater tables are
elevated or when snowpack runoff produces relatively permanent flow,
returning on an annual basis in known, fixed geographic locations.
 By defining ``tributary'' as perennial or intermittent rivers and
streams that contribute surface water flow to traditional navigable
waters or the territorial seas in a typical year, the agencies are
establishing that a mere hydrologic connection cannot provide the basis
for CWA jurisdiction; the bodies of water must be ``geographical
features'' (i.e., rivers and streams) that are ``relatively permanent''
(i.e., perennial or intermittent) and that contribute surface water
flow to a traditional navigable water or the territorial seas in a
typical year. Rapanos, 547 U.S. at 732. This requirement is informed by
Rapanos, wherein the plurality determined that the phrase ``the waters
of the United States'' ``cannot bear the expansive meaning that the
Corps would give it,'' id. at 732, and challenged the notion that
``even the most insubstantial hydrologic connection may be held to
constitute a `significant nexus.' '' Id. at 728. Similarly, Justice
Kennedy noted, ``mere hydrologic connection should not suffice in all
cases; the connection may be too insubstantial for the hydrologic
linkage to establish the required nexus with navigable waters as
traditionally understood.'' Id. at 784-85. The agencies believe that
the requirement that a tributary be perennial or intermittent and be
connected to a traditional navigable water is reasonable and reflects
the plurality's description of a `` `wate[r] of the United States' ''
as ``i.e., a relatively permanent body of water connected to
traditional interstate navigable waters.'' Id. at 742.
 Under the proposed definition of ``tributary,'' an artificial or
natural ephemeral feature would have severed jurisdiction upstream of
the feature, because the waterbody would not contribute surface water
to a paragraph (a)(1) water on a perennial or intermittent basis.
Several commenters supported this approach, noting that waters above
ephemeral breaks are more appropriately subject to State or tribal
jurisdiction. Others criticized the approach as too restrictive and
raised concerns regarding the importance of those upstream waters to
the tributary system. The agencies recognize that the proposed rule's
treatment of ephemeral features would have severed jurisdiction for
certain relatively permanent bodies of water that are regularly
``connected to'' traditional navigable waters in a typical year via
channelized surface water flow through those features. The final rule
has been modified to address these concerns regarding ephemeral breaks
between two relatively permanent waters while remaining faithful to the
text, structure, and legislative history of the CWA and Supreme Court
guidance.
 As discussed in Section III.A.3, the final rule provides that
channelized non-jurisdictional surface water features do not sever
jurisdiction of upstream perennial or intermittent waters so long as
they convey surface water from such upstream waters to downstream
jurisdictional waters in a typical year. The use of ``channelized'' in
this context generally indicates features with a defined path or
course, such as a ditch or the bed of an ephemeral stream. The flow
must be channelized in the sense of being discrete and confined to a
channel, as opposed to diffuse, non-channelized flow. Channelized non-
jurisdictional surface water features are generally continuously
present on the landscape as geomorphic features and may regularly
``connect'' the upstream tributary to the downstream jurisdictional
water such that those waters can mix and become indistinguishable in a
typical year. This may occur, for example, where managed water systems
alter the flow classification of a perennial or intermittent tributary
to ephemeral but the perennial or intermittent flow returns farther
downstream. It could also occur as a result of natural conditions, such
as a tributary that becomes a losing stream for a reach, but then
becomes perennial again downstream of the losing reach. The losing
reach could occur because of water infiltrating into the ground and
recharging groundwater, where the water table is below the bottom of
the channel bed.
 The final rule also allows for other types of artificial or natural
features, such as dams or boulder fields, which may maintain
jurisdiction so long as they convey surface water flow from an upstream
tributary to a downstream jurisdictional water in a typical year. The
agencies have determined in this final rule that such conditions do not
sever jurisdiction for the upstream reach of the tributary if a
channelized non-jurisdictional surface water feature conveys surface
water flow to a downstream jurisdictional water in a typical year. The
agencies have concluded that water flowing through features such as
dams or boulder fields can sustain a regular and predictable surface
water connection between upstream and downstream waters and therefore
can maintain jurisdiction between such waters. In all cases, however,
the excluded or ephemeral feature remains non-jurisdictional. Certain
other excluded features are incapable of providing channelized surface
flow (e.g., groundwater, diffuse stormwater run-off, or directional
sheet flow over upland) and therefore sever jurisdiction upstream of
such excluded features.
 The Supreme Court has not spoken directly to the question of
whether an ephemeral reach along or downstream of an otherwise
jurisdictional tributary severs jurisdiction, and the agencies believe
that the final rule appropriately reflects their statutory authority.
In particular, the plurality decision in Rapanos emphasized that
jurisdictional waters themselves must be relatively permanent and
connected to traditional navigable waters, 547 U.S. at 742, but did not
specify the type of connection necessary between the relatively
permanent waters and downstream traditional navigable waters. Justice
Kennedy's opinion stated that the Corps could identify by regulation
categories of tributaries based on ``their volume of flow (either
annually or on average), their proximity to navigable waters, or other
relevant considerations,'' id. at 780-81, but fails to provide further
guidance. The agencies conclude that the final rule appropriately
reflects and balances these general guiding principles by exercising
jurisdiction over perennial and intermittent tributaries but not
ephemeral streams
[[Page 22290]]
and dry washes, while under certain circumstances allowing such
channelized features to maintain jurisdiction between upstream and
downstream more permanent waters.
 Some commenters agreed with the agencies' proposal that ephemeral
reaches should sever jurisdiction of upstream waters because those
waters no longer have a continuous hydrologic surface connection of
relatively permanent flow to a downstream jurisdictional water. Other
commenters stated that the proposed definition of ``waters of the
United States'' was inconsistent in that some forms of natural or
artificial features could connect upstream tributaries with downstream
jurisdictional waters, whereas ephemeral reaches would have severed
jurisdiction of upstream perennial and intermittent streams. In
addition, many commenters raised concerns about implementing a
definition of ``tributary'' in which an ephemeral feature would sever
jurisdiction of upstream reaches, indicating that it may be difficult
to apply in the field. Commenters also stated that if ephemeral
features severed jurisdiction of perennial and intermittent waters
upstream, many waters in certain regions, such as the arid West, would
be non-jurisdictional. Some commenters expressed concern that the
proposed definition would place a burden on project applicants to
identify and anticipate such ephemeral breaks to avoid potential
responsibility for compensatory mitigation of upstream losses. The
agencies have modified the final rule language in a manner that
addresses these concerns. Under the final rule, tributaries that
contribute surface water flow to a downstream jurisdictional water in a
typical year through certain natural features (such as debris piles or
boulder fields) or artificial features (such as culverts or dams) are
tributaries, even though these features may result in an interruption
in the surface water channel. A perennial or intermittent tributary
above the natural or artificial feature does not lose its
jurisdictional status as long as the natural or artificial feature
continues to convey surface water flow from the upstream reach to a
downstream jurisdictional water in a typical year.
 Commenters also requested clarification on whether a natural
feature through which a tributary flows could be considered a
jurisdictional feature as part of the tributary itself, such as a
boulder field or subterranean river. Natural or artificial features
that do not satisfy the surface water flow conditions of the
``tributary'' definition are not tributaries under this rule, even if
they convey surface water flow from upstream relatively permanent
waters to downstream jurisdictional waters in a typical year. See
Section III.A.3 for additional discussion.
 Some commenters asked for clarification on whether tributaries are
viewed as reaches or as an entire network. The agencies are using the
term ``reach'' in this preamble to the final rule to mean a section of
a stream or river along which similar hydrologic conditions exist, such
as discharge, depth, area, and slope.\45\ If a perennial tributary
becomes intermittent and then ephemeral and then perennial again, it
may be viewed as four separate reaches (e.g., perennial reach,
intermittent reach, ephemeral reach, perennial reach), especially if
they also share other similarities with respect to depth, slope, or
other factors. In general, a reach can be any length of a stream or
river, but the agencies are clarifying for implementation purposes that
such length is bounded by similar flow characteristics.
---------------------------------------------------------------------------
 \45\ See Connectivity Report at A-10, defining ``reach'' as ``a
length of stream channel with relatively uniform discharge, depth,
area, and slope.'' A similar definition is used by the USGS, at
https://www.usgs.gov/faqs/what-a-reach.
---------------------------------------------------------------------------
 Commenters suggested that flow classification and jurisdictional
status could be determined based on the flow in the majority of a reach
(i.e., whether it is perennial, intermittent, and ephemeral), which
they said would be simpler than differentiating various segments from
the broader stream reach. The agencies are not determining flow
classification using the majority of the reach. Under the Rapanos
Guidance, a tributary ``reach'' was identified by a stream order
classification system where the relevant reach was used for purposes of
a significant nexus determination. However, stream order is not
directly relevant to stream and river jurisdiction under this final
rule, and instead flow classification is a key aspect in determining
the jurisdictional status of a tributary. The agencies conclude that
such an approach is easier to implement in light of the final rule's
``tributary'' definition and is more consistent with the legal and
scientific foundation for the rule. Along the length of a tributary,
the flow classification may fluctuate, and the points at which flow
classifications change are the points at which a reach is bounded. If a
tributary flows through a non-jurisdictional ephemeral reach to
downstream jurisdictional waters, the point at which a tributary
becomes ephemeral may fluctuate upstream and downstream in a typical
year based on climatic conditions, changes in topography and
surrounding development, water input, and water withdrawals. When such
a transition zone of flow classification occurs, the agencies will use
best professional judgment and various tools to identify where the
change in flow classification occurs. The agencies have historically
implemented comparable approaches at transition zones, for example with
the identification of the extent of tidal influence (also referred to
as the head of tide). This generally occurs where a river flows into
tidal waters and the agencies must identify the farthest point upstream
where a tributary is affected by tidal fluctuations in order to
determine which lateral extent to apply for the limits of jurisdiction
(i.e., high tide line or ordinary high water mark), permitting
requirements, and similar factors. There is generally not a hard
demarcation distinguishing where a waterbody ceases to be tidal, so the
agencies must use best professional judgment utilizing all available
information and tools which may assist in making the determination. See
Section III.B.3 for additional information.
 Many commenters recommended that tributaries that were altered or
relocated should remain tributaries. The agencies agree with those
comments and, consistent with the proposal, have included that
provision in the final rule. Many commenters expressed concern about
the challenges of implementing a flow-based ``tributary'' definition
where many systems have been modified by human actions. Some commenters
also stated that the use of ``naturally occurring'' in the proposed
``tributary'' definition was unclear and questioned how it would apply
to modified systems. The agencies disagree with the proposition that
identifying flow conditions would be challenging in modified systems.
An altered tributary is one in which the flow or geomorphic conditions
have been modified in some way, for example, by straightening a sinuous
tributary, adding concrete or riprap to stabilize the banks of a
tributary, reducing flow conditions from perennial to intermittent flow
due to water withdrawals, or widening or adding physical features (such
as riffle/pool complex restoration or check dams) to the tributary to
reduce the velocity of flow. A relocated tributary is one in which an
entire portion of the tributary may be moved to a different location,
as when a tributary is rerouted around a city center to protect it from
flooding or around a mining complex to enable extraction of
commercially
[[Page 22291]]
valuable minerals. To be considered a tributary, such features must
continue to meet the flow conditions of the ``tributary'' definition.
The agencies conclude that identifying flow conditions in these
features would be no more challenging than identifying flow conditions
in other tributaries, which the agencies have been doing to apply the
Rapanos Guidance since 2008. In a relocated tributary, the reach that
has been relocated may meet the definition of ``ditch'' or may be
colloquially called a ditch, which is why, for simplicity and clarity,
the agencies have included these ditches in the definition of
``tributary.'' The agencies also believe that retaining jurisdiction
over the relocated tributary is consistent with its legal authorities
and the agencies' treatment of impoundments of jurisdictional waters
(see Section III.F), which may alter the course or form of a water of
the United States but maintains sufficient surface water connection to
a traditional navigable water in a typical year.
 Some commenters requested clarification on how water diversions may
affect the jurisdictional status of tributaries. A water diversion that
completely reroutes a tributary through a tunnel would be considered an
artificial feature that would not sever jurisdiction under this final
rule. The tunnel itself is not a tributary under the rule, however,
because it is not a surface water channel. This final rule clarifies
that jurisdiction applies based on current flow classification in a
typical year. When completing jurisdictional determinations in managed
systems, just as in natural systems, the agencies will consider whether
features meet the flow conditions of the ``tributary'' definition in a
typical year. Managed systems are jurisdictional as long as they
satisfy the definition of ``tributary,'' including the flow conditions.
If a stream is ephemeral in a typical year due to managed water
withdrawals, the feature is an excluded ephemeral stream. Tributaries
that have been altered via water management systems, or whose
morphology has been altered in some manner, maintain their tributary
status as long as they are perennial or intermittent and contribute
surface water flow to the territorial seas or a traditional navigable
water in a typical year.
 Under the pre-existing regulatory regime (recodified in the 2019
Rule), the agencies conducted a significant nexus analysis for certain
types of waters referred to as ``non-relatively permanent waters,''
which includes ephemeral features and some intermittent streams. See
Rapanos Guidance at 7 (`` `[R]elatively permanent' waters do not
include ephemeral tributaries which flow only in response to
precipitation and intermittent streams which do not typically flow
year-round or have continuous flow at least seasonally. However, CWA
jurisdiction over these waters will be evaluated under the significant
nexus standard[.]''). The definition of ``tributary'' in the final rule
replaces existing procedures that utilize a case-specific ``significant
nexus'' analyses of the relationship between a particular stream and
downstream traditional navigable water. The agencies are eliminating
this case-specific ``significant nexus'' analysis by providing a clear
definition of ``tributary'' that is easier to implement. Justice
Kennedy's ``significant nexus'' test for wetlands adjacent to
nonnavigable tributaries was needed only ``absent more specific
regulations,'' Rapanos, 547 U.S. at 782, because ``the breadth of [the
Corps' existing tributary] standard . . . seems to leave wide room for
regulation of drains, ditches, and streams remote from any navigable-
in-fact water and carrying only minor water volumes towards it'' and
thus ``precludes its adoption as the determinative measure of whether
adjacent wetlands are likely to play an important role in the integrity
of an aquatic system comprising navigable waters as traditionally
understood.'' Id. at 781. In light of the ``more specific [tributary]
regulations'' finalized in this rule, the agencies are eliminating the
case-specific significant nexus review through categorical treatment,
as ``waters of the United States,'' of all tributaries with perennial
or intermittent flow that contribute surface water flow to downstream
navigable-in-fact waters in a typical year. See id. at 780-81 (Kennedy,
J., concurring in the judgment) (``Through regulations or adjudication,
the Corps may choose to identify categories of tributaries that, due to
their volume of flow (either annually or on average), their proximity
to navigable waters, or other relevant considerations, are significant
enough that wetlands adjacent to them are likely, in the majority of
cases, to perform important functions for an aquatic system
incorporating navigable waters.'') (emphasis added). In doing so, the
agencies believe they avoid interpretations of the CWA that raise
significant constitutional questions. See id. at 738 (plurality)
(``Even if the term `the waters of the United States' were ambiguous as
applied to channels that sometimes host ephemeral flows of water (which
it is not), we would expect a clearer statement from Congress to
authorize an agency theory of jurisdiction that presses the envelope of
constitutional validity.'').
 The agencies recognize that this is a departure from prior
positions of the Federal government. The agencies also recognize that
prior to the finalization of this rule, some courts applied the
significant nexus standard articulated in Justice Kennedy's opinion as
the exclusive test of CWA jurisdiction over certain waters. As
described in detail in Section II.E, the agencies have analyzed the
text, structure, and legislative history of the CWA in light of Supreme
Court guidance and conclude that this final rule incorporates important
aspects of Justice Kennedy's opinion, together with those of the
plurality, to craft a clear and implementable definition that stays
within their statutory and constitutional authorities.
 The final ``tributary'' definition contains no flow volume
requirement, but only a requirement of perennial or intermittent flow
and a contribution of surface water flow to a paragraph (a)(1) water in
a typical year. The agencies believe that establishing a specific flow
volume requirement for all tributaries is inappropriate, given the wide
spatial and temporal variability of flow volume in rivers and streams
across the country. While the definition may in certain instances
assert jurisdiction over bodies of water contributing ``the merest
trickle,'' 547 U.S. at 769 (Kennedy, J., concurring in the judgment),
to a traditional navigable water during certain times of the year, the
agencies conclude that such bodies are `` `waters' in the ordinary
sense of containing a relatively permanent flow'' regardless of flow
volume. Id. at 757 (Scalia, J., plurality).
 Some commenters suggested that using stream flow volumes rather
than flow duration classifications for the definition of ``tributary''
would be easier to implement. The agencies disagree with this
suggestion based on their experience. In 1977, the Corps proposed to
use flow volumes (i.e., five cubic feet per second) to define
``headwaters'' in the definition of ``waters of the United States,''
and instead finalized the use of flow volumes for implementation of
their general permit program. 42 FR 37129 (July 19, 1977). Stream flow
volume is challenging to measure directly, in particular in an
intermittent stream where flow is not always present and may require
multiple field-based measurements that can make implementation
inefficient and result in delays in making a jurisdictional
determination. While flow duration classifications may also require
field measurements, in certain instances
[[Page 22292]]
remote tools, such as remote sensing and aerial photography, can be
used to observe presence or absence of flow and identify flow duration
classifications, but cannot also assess flow volumes. In addition, the
agencies have not identified a reasonable or appropriate rationale or
justification for specific flow volumes that should establish
jurisdiction given the broad nationwide applicability of the final
rule.
 A few commenters requested a flow duration metric (e.g., 30, 90, or
185 days) to determine a jurisdictional tributary. Several commenters
recommended the agencies adopt a definition of ``intermittent'' that
contains the requirement of continuous flow for a specific duration,
such as ``at least one month of the calendar year'' to provide
certainty for determining flow classification. See e.g., 30 CFR 710.5
(definition of ``intermittent'' used in a U.S. Department of Interior
regulation). Several commenters also recommended a regionalized
approach to flow classification. The agencies have finalized an
approach that considers streamflow duration in the flow classification
definitions generally (e.g., ``flowing continuously year-round,''
``flowing continuously during certain times of the year and more than
in direct response to precipitation,'' and ``flowing . . . only in
response to precipitation'') but without specifying an exact number of
days of flow. 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. The ``typical year'' construct
captures that variability, however, and provides for regional and local
variations in the actual application of a uniform nationwide
definition. The agencies acknowledge that an approach utilizing a
specific duration would provide for enhanced national consistency, but
it would also undermine the regionalized implementation of intermittent
tributaries as provided for under this final rule. Some commenters
cautioned the agencies against treating intermittent streams similarly
across the country based on a prescriptive flow duration metric, as
intermittent streams in the arid West are fundamentally different from
intermittent streams in the Southeast, for example. A specific duration
requirement would also be challenging to implement--even landowners
familiar with their properties may not know the number of days a stream
flows per year.
 Other commenters recommended the use of physical indicators of
flow, such as ordinary high water mark and bed and banks, which could
be regionalized for a field-based approach. These commenters stated
that physical indicators can be more readily observable and can
indicate flows of sufficient magnitude and duration to qualify as a
tributary. The agencies disagree with these comments and 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. See, e.g.,
547 U.S at 781 (Kennedy, J., concurring in the judgment) (expressing
concerns that a the Corps' existing tributary standard based, in part,
on the ``possess[ing]'' of ``an ordinary high water mark, defined as a
`line on the shore established by the fluctuations of water and
indicated by [certain] physical characteristics,' . . . seems to leave
wide room for regulation of drains, ditches, and streams remote from
any navigable-in-fact water and carrying only minor water volumes
towards it''). For example, ephemeral streams can have an ordinary high
water mark and bed and banks, which would not allow for the agencies or
the public to distinguish between a non-jurisdictional ephemeral stream
and a jurisdictional intermittent or perennial tributary using those
physical indicators. Ephemeral streams in the arid West, for example,
may have ordinary high water marks that were incised years ago
following a single large storm. It makes more practical sense for a
feature to be first assessed as a tributary, after which the lateral
extent of that tributary can be identified using the ordinary high
water mark.
 Physical indicators, however, may be one line of evidence the
agencies could use to evaluate whether a stream meets the flow
requirements to be a tributary under this definition. These indicators
could be regionalized to obtain a practical field-based approach for
identifying the flow classification of a stream which is a required
component of identifying a tributary. Such physical indicators are
further discussed in Section III.D.3 of this notice. In addition, the
agencies cannot always rely on field-based physical indicator methods--
for example, when evaluating a site at a time that does not meet the
definition of ``typical year.'' In some instances, completing a desktop
determination with remote tools may supplement or substitute for field-
based indicators.
3. How will the agencies implement the final rule?
 The agencies will employ many different methods and tools to
identify and determine whether a feature meets the definition of
``tributary'' under this final rule. A few commenters recommended that
the agencies identify a variety of methods which may be employed to
identify flow classifications, and that such methods involve tools
readily available to a typical landowner. Methods and tools used by the
agencies are generally available for the public to use so that they can
make an informed decision about how to proceed with requests for
jurisdictional determinations or authorization for activities under the
CWA. The agencies believe that there are numerous cases where an
informed decision can save valuable time and money by avoiding
unnecessary jurisdictional determination requests. This can be done,
for example, where landowners are familiar with the water features on
their property and know that they only flow in response to a rain
event, or that an isolated wetland in the middle of a ranch is not
flooded by a nearby perennial river in a typical year. However, in
cases where a member of the general public makes an informed decision
to not request a jurisdictional determination and discharges pollutants
into a waterbody that is, in fact, jurisdictional without required
permits, the individual could be subject to the agencies' enforcement
authorities under the CWA.
 One of the first steps in determining whether a feature is a
tributary is to identify relevant features on the landscape, such as
rivers, streams, or similar naturally occurring surface water channels,
as well as ditches. Field work to include direct observation and other
reliable methods can indicate the existence of a tributary, such as
stream gage data, elevation data, historic or current water flow
records, flood predictions, statistical evidence, aerial imagery, and
USGS maps.
 Another step in determining whether a feature is a tributary is to
identify whether the feature contributes surface water flow to a
paragraph (a)(1) water either directly or through one or more paragraph
(a)(2) through (4) waters in a typical year. The agencies intend to use
several sources to identify the flow path of a potential tributary to
determine whether surface water flow is being contributed eventually to
a paragraph (a)(1) water. The agencies can use USGS maps, State and
local knowledge or maps, aerial photography, or other remote sensing
information so long as
[[Page 22293]]
the tools the agencies use have been verified to be reliable (see,
e.g., Section IV of this notice regarding limitations of existing
aquatic resource mapping datasets) to assess a feature's flow path. The
agencies can also use available models, including models developed by
Federal, State, tribal and local governments, academia, and the
regulated community. One such model includes the ``Flow (Raindrop)
Path'' GIS tool which allows the user to click a point on a map to
signify a falling raindrop on that point, after which a flow path is
drawn to estimate where the raindrop may flow, eventually making its
way to the ocean if the tributary network allows for it (https://streamstats.usgs.gov/ss/). The StreamStats tool may potentially be used
to identify the flow path from the subject water to the downstream
paragraph (a)(1) water using the ``Flow (Raindrop) Path'' component of
the tool. These tools could be used in conjunction with field
observations, data, and other desktop tools to evaluate whether a
specific point on a potential tributary may have a surface water
connection to a downstream paragraph (a)(1) water in a typical year.
 In addition to identifying the presence of rivers, streams, or
similar naturally occurring surface water channels which contribute
surface water flow to a downstream paragraph (a)(1) water, the agencies
must assess the feature's flow classification. The agencies have
substantial experience using visual hydrologic observations, field data
and indicators, and remote tools to determine flow classification.
Commenters expressed several key concerns about the flow classification
concept. Some commenters noted that there is no established or
universally accepted methodology to identify flow classification. The
agencies agree that there is no universally accepted methodology;
however, scientists, environmental consultants, and other water
resource professionals, including agency staff, have used the terms
``perennial,'' ``intermittent,'' and ``ephemeral'' for decades in the
field. Indeed, the agencies have used these terms to evaluate the
jurisdictional status of waters for more than a decade, in accordance
with the 2008 Rapanos Guidance.\46\ More recently, the Corps has
applied these terms in its Nationwide Permit Program (NWP). See 82 FR
1860, 2005 (January 6, 2017). The terms are used in the NWP in a manner
similar to the definitions in this final rule, but in the NWP the terms
adhere more closely to the generally-accepted scientific definitions
that focus on groundwater rising above the bed of the stream channel as
differentiating between ephemeral features and perennial and
intermittent waters. See id. at 2006. For the reasons explained in
Section III.A.2, however, the agencies have finalized definitions for
the three flow classification terms in this rule that better align with
the scope of CWA jurisdiction, while improving clarity of the rule and
transparency of the agencies' implementation. These flow classification
terms can be implemented using readily available resources in addition
to visual assessments.
---------------------------------------------------------------------------
 \46\ Under the Rapanos Guidance, the agencies applied a
different jurisdictional test based upon a tributary's flow regime.
``The agencies will assert jurisdiction over relatively permanent
non-navigable tributaries of traditional navigable waters without a
legal obligation to make a significant nexus finding.'' Rapanos
Guidance at 7. Relatively permanent tributaries were described in
the guidance as tributaries that ``typically flow year-round or have
continuous flow at least seasonally (e.g., typically three
months)[.]'' Id. at 1. At the same time, the guidance established
that `` `relatively permanent' waters do not include ephemeral
tributaries which flow only in response to precipitation and
intermittent streams which do not typically flow year-round or have
continuous flow at least seasonally. . . . CWA jurisdiction over
these waters will be evaluated under the significant nexus [test.]''
Id. at 7. The agencies also note that in June 2009, the Corps added
a classification code ``R6,'' entitled ``Riverine Ephemeral,'' to
identify ephemeral aquatic resources. The Corps created the ``R6''
code to provide clarity to field staff when identifying ephemeral
waters for entry into the ORM2 database. See https://www.spa.usace.army.mil/Portals/16/docs/civilworks/regulatory/Bulk%20Upload/Bulk%20Data%20Cowardin.pdf.
---------------------------------------------------------------------------
 Some commenters expressed concern that the information needed to
determine flow classification would require a high burden of proof and
would result in significantly longer processing times for
jurisdictional determinations. The agencies will continue to bear the
burden of proof for determinations and, as noted above, have already
implemented a version of the flow classification concept under the
Rapanos Guidance and the Corps' NWP. The agencies disagree with the
suggestion that the use of these flow classifications will result in a
lengthier process for jurisdictional determinations. With the clear and
categorical definition as to the scope of CWA jurisdiction included in
this final rule, the elimination of the significant nexus determination
requirement for tributaries, the use of existing tools, and the
development of new tools, jurisdictional determinations for tributaries
should be more efficient under this final rule than under prior
regulatory regimes.
 Some commenters also noted that the data and resources identified
in the preamble to the proposed rule to evaluate flow classification
have limited availability. The agencies agree that some data and
resources have significant limitations and other national-level tools
and methods may not be readily available or accurate for use in many
areas of the country, including in rural or remote areas and in heavily
modified systems. The agencies will continue to rely on local
knowledge, information provided by the landowner, and local, State, and
tribal agencies, and a variety of additional tools and resources to
evaluate flow classification in such systems. The final rule language
on flow classifications allows for consistent implementation approaches
for modified systems and more natural systems.
 Visual observations of surface hydrology are a useful primary
method to identify flow classifications. The agencies expect that
landowners will often have sufficient knowledge to understand how water
moves through their properties, although visual observations could be
conducted by Federal, State, tribal and local agencies, and other
public or private organizations, as appropriate. The agencies also
recognize that a single visual observation may not always be sufficient
to accurately determine flow classification, and visual observations
should generally be combined with precipitation and other climate data
and expected flow seasonality to accurately determine flow
classification. For example, observing flow directly after a large
rainfall or observing no flow during a dry season may not be good
indicators of a stream's typical flow classification.
 In addition to visual observations of surface hydrology, the
agencies may use field-based indicators and tools as another line of
evidence to determine flow classification. Some commenters recommended
using local flow data collected by government agencies, where
available, and the agencies acknowledge that this could be a useful
source of data. The agencies have also used methods such as trapezoidal
flumes and pressure transducers for measuring surface flow. During the
public comment period, many commenters mentioned the availability of
existing rapid, field-based, streamflow duration assessment methods
that have been developed for use across various States or geographic
regions and suggested that these existing methods could be used to
distinguish between streams with perennial, intermittent, and ephemeral
flow classifications. Many commenters also recommended that the
agencies develop
[[Page 22294]]
similar methods for use across the United States, with input from the
public and the scientific community.
 The agencies recognize that some States have developed streamflow
duration assessment methods (SDAMs) that use physical and biological
field indicators, such as the presence of hydrophytic vegetation and
benthic macroinvertebrates, to determine the flow duration class of a
stream reach as perennial, intermittent, or ephemeral (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 http://portal.ncdenr.org/c/document_library/get_file?uuid=0ddc6ea1-d736-4b55-8e50-169a4476de96&groupId=38364). The EPA, the Corps, and the State of
Oregon also previously developed a regionalized SDAM that has been
validated for use throughout the Pacific Northwest since 2015
(available at http://www.epa.gov/measurements/streamflow-duration-assessment-method-pacific-northwest).
 Because SDAMs use indicators that are robust to seasonal and short-
term climatic variability, these methods can be applied in a single
site visit to distinguish streamflow duration when a channel is flowing
or in the absence of flow. The agencies agree with commenters that
these methods are useful and practical tools that could be used to help
inform timely and predictable jurisdictional determinations, for
implementation of the final ``tributary'' definition, in the States and
regions where previously developed SDAMs are available. The agencies
also agree with commenters that developing similar methods for use
across the United States would promote consistent implementation of the
final tributary definition and note that the agencies are currently
working to develop regionally-specific SDAMs for nationwide coverage.
The agencies believe that developing regionally-specific SDAMs is
important to account for the differences in climate, geology, and
topography that can influence relationships between physical and
biological indicators and streamflow permanence.
 A variety of remote, desktop tools could be used to determine flow
classification of potential tributaries, particularly when coupled with
site specific information. In meetings with stakeholders, some local
government officials recommended using local maps developed by
government agencies, where available, as opposed to national maps,
noting for example that the National Hydrography Dataset (NHD) has been
shown to overestimate flow in certain areas. The agencies will assess
flow classification using a compilation of the best available mapping
sources, which may include the NHD \47\ or local maps, as well as other
remote tools such as photographs, StreamStats by the USGS (available at
https://streamstats.usgs.gov/ss/), Probability of Streamflow Permanence
(PROSPER) by the USGS (available at https://www.usgs.gov/centers/wy-mt-water/science/probability-streamflow-permanence-prosper), Natural
Resources Conservation Service (NRCS) hydrologic tools and soil maps,
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), USGS topographic data, or
modeling tools using drainage area, precipitation data, climate,
topography, land use, vegetation cover, geology, and/or other publicly
available information. The agencies will continue to rely on field
observations and field data to verify desktop assessments as
appropriate, and will also consider data and tools developed by
academia, the regulated community, and other stakeholders.
---------------------------------------------------------------------------
 \47\ As described in the RPA for the final rule, the agencies
note that NHD at High Resolution does not distinguish intermittent
from ephemeral features in most parts of the country and may not
accurately identify on-the-ground flow conditions.
---------------------------------------------------------------------------
 Ultimately, multiple data points and multiple sources of
information should be used to determine flow classification. For
example, a ``blue line stream'' on a USGS topographic map and/or mapped
in the NHD may indicate a potential tributary. Combining this
information with stream order can further inform determinations of flow
classification, as higher order streams may be more likely to exhibit
perennial or intermittent flow compared to lower order streams, though
some headwater streams are perennial or intermittent. The agencies
could further determine whether flow data, field indicators, or visual
observations of surface hydrology are available to confirm a stream's
flow classification. Field-based and remote information may vary in
availability and accuracy in different parts of the country, so care
will be taken to evaluate additional information prior to reasonably
determining the presence or absence of a tributary. Also, the agencies
will continue to use the specific, validated tools developed by States
to identify stream flow classifications.
 As noted previously, the agencies will use best professional
judgment and various tools to identify where the change in flow
classification occurs (e.g., from intermittent to ephemeral and vice-
versa). The tools described above can assist in the identification of
that transition in flow classification and therefore the delineation of
a reach as used in this final rule. The primary distinction necessary
under this rule is the identification of when a perennial or
intermittent reach transitions to an ephemeral reach and vice-versa.
The agencies acknowledge that there are spatial and temporal variations
in stream attributes such that there may not always be a distinct point
demarcating the flow classification changes. For example, a single
distinct point may occur at the confluence of two ephemeral streams,
which become intermittent at the confluence. However, in some
situations between stream confluences, there may be a transition zone
where the flow classification change fluctuates within that zone
throughout a typical year. The agencies will gather information from
upstream and downstream of the transition zone as far as needed to get
an accurate assessment of the conditions on the ground when it may be
necessary for a decision point. This transition zone where the change
in flow classification occurs will be evaluated by the agencies using
the tools described above, as well as best professional judgment, to
identify the most appropriate point at which to distinguish flow
classifications.
 In addition to determining the flow classification of a potential
tributary, the agencies will also determine whether climatic conditions
are typical to determine whether the water feature meets the definition
of ``tributary'' under the final rule. As discussed in Section III.A.1,
the final rule defines the term ``typical year'' to mean ``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.'' The agencies will use readily available climatic data and
tools to evaluate normal precipitation and climatic conditions for the
region at issue and will ensure that the time period of evaluation is
representative of the normal characteristics of the subject waterbody
(i.e., it is neither too wet nor too dry). A detailed discussed of how
the agencies intend to implement this definition is provided in Section
III.A.1.
 In utilizing the data sources described above and determining the
flow classifications of tributaries under typical climatic conditions,
the agencies recognize the need to consider seasonality and timing of
tributary
[[Page 22295]]
flows. For instance, in some geographic areas, intermittent streams may
typically flow only at certain times, such as during seasonally wet
conditions. Thus, the agencies would not expect to observe streamflow
in seasonally dry conditions, even if precipitation during those dry
conditions is considered typical for the dates of interest. The
agencies may need to use the multiple tools described above to
determine the flow classification for a tributary that is not flowing
because of seasonally dry conditions, including remote- and field-based
hydrologic and non-hydrologic indicators of the flow classification
that would occur during seasonally wet conditions. For example, remote
indicators might include a series of aerial and satellite images,
spanning multiple years and taken under normal climatic conditions, the
majority of which depict water flowing in the channel.
 In the field, evidence of recent flow can be observed through the
presence of multiple or abundant signs of certain ordinary high water
mark indicators for the region, such as the presence of point bars,
concentrations of drift deposits, or the destruction of terrestrial
vegetation. Furthermore, certain wetland hydrology indicators can help
clarify whether water is present in the area only immediately following
precipitation events, or whether longer-term saturation has likely
occurred. An example of an indicator is the presence of oxidized
rhizospheres along living root channels, which can take four to eight
weeks of continuous saturation to form. This indicator alone cannot be
conclusive of water flowing above the surface, but multiple positive
indicators could provide an increased degree of confidence in these
situations. Conversely, the agencies may observe flow during wetter
than normal precipitation conditions. In this case, the agencies can
use other lines of evidence, including remote- and field-based
hydrologic and non-hydrologic indicators of flow classification as
appropriate. Streams that contain flowing water during wetter than
normal climatic conditions, but which lack an ordinary high water mark
or hydrology indicators may be less likely to flow during normal
climatic conditions. This assessment is further supported if the
majority of wet season aerial and satellite images taken during normal
climatic conditions depict a dry channel. In addition, a landowner's
specific information indicating whether a water feature meets the
definition of a ``tributary'' under ``typical year'' conditions may
also aid in determining flow classification.
 In addition to requesting clarification about when a surface water
feature meets the definition of ``tributary,'' some commenters also
stated that it would be helpful to incorporate the lateral limits of
jurisdiction directly into the ``tributary'' definition and questioned
how such limits would be determined. In addition, some commenters
expressed concern regarding the status of braided rivers that migrate
and have multiple channels where the jurisdictional limits would be
identified. The lateral limits of jurisdiction for tributaries extends
to the ordinary high water mark, as indicated by the physical
characteristics provided in the definition. Consistent with existing
practice, the agencies intend to continue to use the Corps' ordinary
high water mark manuals, as well as Regulatory Guidance Letter 05-05,
when making ordinary high water mark determinations.\48\ The outer
limits of a braided channel may be used to identify the lateral extent
when appropriate, which may encompass multiple low-flow channels and
the migratory islands that separate them. Adding the ordinary high
water mark concept to the definition of ``tributary'' is unnecessary
because it is already located in the Corps' regulations at 33 CFR 328.4
to identify the lateral extent of jurisdiction. The agencies are
finalizing the rule with the definition of ``ordinary high water mark''
as proposed, however, to improve consistency between the corresponding
regulations and also because the term ``ordinary high water mark'' is
used in the final rule's definition of ``upland.''
---------------------------------------------------------------------------
 \48\ The Corps' ordinary high water mark manuals are available
at: https://www.erdc.usace.army.mil/Media/Fact-Sheets/Fact-Sheet-Article-View/Article/486085/ordinary-high-water-mark-ohwm-research-development-and-training/. Regulatory Guidance Letter 05-05 is
available at: https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll9/id/1253.
---------------------------------------------------------------------------
E. Ditches
1. What are the agencies finalizing?
 The regulatory status of ditches has long created confusion for
farmers, ranchers, irrigation districts, municipalities, water supply
and stormwater management agencies, and the transportation sector,
among others. To address this confusion, the agencies proposed to add a
new category to the definition of ``waters of the United States'' for
jurisdictional ditches and similar artificial features. The agencies
proposed to include in that category: (1) Ditches that are traditional
navigable waters or that are subject to the ebb and flow of the tide
(e.g., paragraph (a)(1) waters); (2) ditches that are constructed in
tributaries or that relocate or alter tributaries as long as the ditch
satisfies the flow conditions of the tributary definition; and (3)
ditches constructed in adjacent wetlands as long as the ditch likewise
satisfies the conditions of the tributary definition. 84 FR 4203. All
other ditches were excluded from CWA jurisdiction under the proposal.
 Many commenters did not find that the separate jurisdictional
category of ``ditches'' provided the regulatory clarity and
predictability that the agencies had sought. They instead stated that
the separate category created confusion. Other commenters said that the
proposed separate category provided additional clarity, while others
argued that all ditches should be excluded. Other commenters stated
that the proposal was too limiting and should include more ditches as
jurisdictional, including any ditch that contributes perennial,
intermittent, or ephemeral flow to other ``waters of the United
States.''
 In response to these diverse comments, the final rule does not
include the separate category of ``ditches'' under paragraph (a)(3) as
proposed and instead incorporates the elements of the proposal into the
``tributary'' category, with some additional clarifying edits. Ditches
that are paragraph (a)(1) waters do not need to be identified in
another jurisdictional category, so that aspect of the proposal has
been eliminated as unnecessary and redundant. Ditches that are
constructed in or that relocate a tributary are included in the final
rule as tributaries, as long as the ditch satisfies the flow conditions
of the ``tributary'' definition. The same is true for ditches that are
constructed in adjacent wetlands.
 The agencies did not retain the term ``alter'' from the proposed
rule given the potential confusion associated with the use of that
term. As some commenters noted, most, if not all, ditches may have some
effect on and therefore may ``alter'' a tributary or some portion of
the tributary system. As described throughout this notice, the CWA does
not authorize the agencies to regulate all waters, nor does it
authorize the agencies to regulate all ditches that exist across the
landscape to assist in water management activities. The agencies
conclude that ditches that are ``constructed in'' or that ``relocate''
a tributary, and that satisfy the flow conditions of the ``tributary''
definition, are appropriately within the authority granted to the
agencies under the CWA, consistent with the legal principles outlined
in Section II.E. The regulation
[[Page 22296]]
and management of all other ditches is appropriately left to States and
Tribes as part of their primary authority over land and water resources
within their border. See 33 U.S.C. 1251(b), 1370.
 The agencies consider it to be clearer to include in the definition
of ``tributary'' that the alteration of a tributary does not modify its
jurisdictional status as a tributary as long as it continues to meet
the flow conditions of the definition, rather than to classify the
alteration of a tributary as a ditch. This is also consistent with
longstanding agency practice. The agencies have modified the exclusion
for ditches in paragraph (b)(5) to reflect these changes. The agencies
also recognize that in certain circumstances, ditches that are
constructed in adjacent wetlands that lack sufficient flow to be
considered tributaries under this final rule may develop wetland
characteristics if not maintained. As discussed below, in limited
circumstances, those wetlands may be treated as adjacent wetlands,
subject to the permitting exemptions in 33 U.S.C. 1344(f). All other
ditches are excluded under the final rule.
 The agencies believe that this approach to ditches best addresses
the comments received and provides clarity and regulatory certainty to
determine when a ditch may be a jurisdictional water and when a ditch
may be excluded, consistent with the agencies' authority under the CWA.
Finally, as discussed in Section III.A.3, non-jurisdictional ditches
under this final rule may be capable of conveying channelized surface
water flow between upstream relatively permanent jurisdictional waters
and downstream jurisdictional waters in a typical year. In this
example, the ditch itself, however, would remain non-jurisdictional.
2. Summary of Final Rule Rationale and Public Comment
 During the 1970s, the Corps interpreted its authorities under the
CWA as excluding drainage and irrigation ditches from the definition of
``waters of the United States.'' See, e.g., 40 FR 31320, 31321 (July
25, 1975) (``Drainage and irrigation ditches have been excluded.'').
The ditch exclusion was expressly stated in regulatory text in the
Corps' 1977 regulations. 33 CFR 323.2(a)(3); 42 FR 37122, 37144 (July
19, 1977) (``manmade nontidal drainage and irrigation ditches excavated
on dry land are not considered waters of the United States under this
definition''). As the Corps explained in 1977: ``nontidal drainage and
irrigation ditches that feed into navigable waters will not be
considered `waters of the United States' under this definition. To the
extent that these activities cause water quality problems, they will be
handled under other programs of the FWPCA, including Section 208 and
402.'' 42 FR at 37127 (July 19, 1977). Similar statements in preambles
to the proposed rules from the early 1980s confirmed this
interpretation: ``man-made, non-tidal drainage and irrigation ditches
excavated on dry land are not considered waters of the United States.''
45 FR 62732, 62747 (September 19, 1980); see also 48 FR 21466, 21474
(May 12, 1983) (``Waters of the United States do not include the
following man-made waters: (1) Non-tidal drainage and irrigation
ditches excavated on dry land, (2) Irrigated areas which would revert
to upland if the irrigation ceased.'').
 The general exclusion for non-tidal drainage and irrigation ditches
excavated in dry land continued through 1986, although the Corps
modified its earlier statements that year by noting in preamble text
that ``we generally do not consider'' such features to be ``waters of
the United States,'' and indicating that the agency would evaluate
certain ditches on a case-by-case basis. 51 FR 41206, 41217 (November
13, 1986).\49\ The EPA also included similar language in a Federal
Register notice in 1988. 53 FR 20764 (June 6, 1988). The Corps further
clarified the regulation of ditches in its nationwide permit regulation
in March 2000, stating that ``non-tidal drainage ditches are waters of
the United States if they extend the [ordinary high water mark] of an
existing water of the United States.'' 65 FR 12818, 12823 (March 9,
2000). In other words, if flow or flooding from a jurisdictional non-
tidal river or stream inundated an upland ditch, the agencies would
assert jurisdiction over that upland ditch because the ordinary high
water mark of the river or stream extends into the ditch, and the
agencies would then assert jurisdiction over the entire reach of that
ditch.
---------------------------------------------------------------------------
 \49\ The Corps also moved the ditch exclusion from rule text to
preamble language in 1986 but stated that this was not a substantive
change and that jurisdiction was not expanded. 51 FR 41206, 41216-17
(November 13, 1986).
---------------------------------------------------------------------------
 This final rule clarifies the regulatory status of ditches in a
manner that is more consistent with the Corps' regulations following
the 1972 and 1977 CWA amendments, with some modifications to provide a
clear definition that also falls within the scope of the agencies'
authority under the CWA. When Congress enacted the 1972 amendments, it
specifically included ditches and related artificial features as
``point sources,'' declaring them to be ``discernible, confined, and
discrete conveyances . . . from which pollutants are or may be
discharged.'' Public Law 92-500, 86 Stat. 816, 887 (1972) codified at
33 U.S.C. 1362(14). Congress envisioned protecting the quality of the
navigable waters, defined as ``waters of the United States'' at that
time, by regulating the discharge of pollutants from conveyances like
pipes, ditches, channels, tunnels and similar features into waters of
the United States. Id. at 1362(12) (defining ``discharge of pollutant''
as ``any addition of any pollutant to navigable waters from any point
source'').
 The agencies evaluated the treatment of ditches in the CWA and its
legislative history to discern whether Congress intended ditches to be
point sources, navigable waters, or both. For example, Congress
exempted the discharge of dredged or fill material into waters of the
United States when that discharge occurs as a result of the
construction or maintenance of irrigation ditches, the maintenance of
drainage ditches, or minor drainage associated with normal farming
activities. 33 U.S.C. 1344(f)(1)(A), (C) (exempting such activities
from sections 301, 402, and 404 of the Act). One possible
interpretation of these exemptions is that they function as an implicit
acknowledgement that there may be some irrigation or drainage ditches
that are waters of the United States, thus the need to exempt common
agricultural and related practices in those waters from CWA section 404
permitting. Another interpretation is that dredged or fill material or
other pollutant discharges arising from such activities are not subject
to federal permitting if those materials get washed down the ditch into
a connected water of the United States.
 For irrigation ditches, which typically are constructed in upland
but frequently must connect to a water of the United States to either
capture or return flow, Congress exempted both the construction and
maintenance of such facilities. 33 U.S.C. 1344(f)(1)(C); see also 33
U.S.C. 1362(14) (excluding agricultural stormwater discharges and
irrigation return flows from the definition of ``point source'').\50\
The
[[Page 22297]]
construction activities performed in upland areas are beyond the reach
of the CWA, but the permitting exemption applies to the diversion
structures, weirs, headgates, and other related facilities that connect
the irrigation ditches to jurisdictional waters. See, e.g., Corps,
Regulatory Guidance Letter No. 07-02, at 1-2 (July 4, 2007).
---------------------------------------------------------------------------
 \50\ The agencies also note that Congress exempted the discharge
of irrigation return flows into waters of the United States from the
section 402 permit program. 33 U.S.C. 1342(l). This exemption
potentially would not be needed if agricultural drainage ditches
carrying irrigation return flow were themselves waters of the United
States, as the entry point of the irrigation return flow into the
drainage ditch might then lack the requisite point source
discharging mechanism given the diffuse overland flow entry point
from the field to ditch in most circumstances.
---------------------------------------------------------------------------
 For drainage ditches, by contrast, the permitting exemption is
limited to only maintenance of such ditches. 33 U.S.C. 1344(f)(1)(C).
That is because a parallel exemption for construction would allow the
drainage of wetlands subject to CWA jurisdiction without a permit.
Congress' intent to prevent such a result is evident in the
``recapture'' provision of 33 U.S.C. 1344(f)(2). See, e.g., Sen. Rpt.
95-370, 95th Cong. 1st Sess., at 76-77 (July 19, 1977) (noting that
exempted ``activities should have no serious adverse impact on water
quality if performed in a manner that will not impair the flow and
circulation patterns and the chemical and biological characteristics of
the affected waterbody'' and noting that the ``exemption for minor
drainage does not apply to the drainage of swampland or other
wetlands'').
 In summary, Congress may have envisioned the interconnection
between the irrigation and drainage ditches and down-gradient waters of
the United States as creating the need for the section 404(f)
permitting exemptions, not necessarily that those ditches themselves
are waters of the United States. Or Congress could have envisioned that
some drainage ditches constructed in jurisdictional wetlands become
waters of the United States themselves and thus require section 404(f)
permitting exemptions for maintenance work performed in them. The
agencies have not been able to identify any legislative history that
signals the clear intent of Congress on this complex topic, and
commenters provided a diverse range of viewpoints that failed to
provide a clarifying position. To resolve the ambiguity, the agencies
are interpreting the statutory text in section 404(f) and its
legislative history as an indication that Congress may have intended,
in certain limited circumstances, that ditches constructed in
jurisdictional wetlands could become jurisdictional waters themselves.
The agencies believe that the final rule formulation adheres more
closely to the language of the statute and the positions articulated by
the plurality opinion in Rapanos. See, e.g., 547 U.S. at 735-36 and
n.7.
 Many commenters requested the agencies clarify that a water of the
United States and point source are mutually exclusive. Some commenters
expressed concern about features which may be considered point sources
rather than waters of the United States under the proposed rule, and
whether such features would require section 402 permits to convey
pollutants downstream. Other commenters stated that permit requirements
may need to be modified by sampling at the downstream end of the ditch
to demonstrate that pollutants are being added to a water of the United
States. The final rule does not make any changes to the agencies'
interpretation of the definition of ``point source'' in CWA section
502(14). The agencies believe that this final rule will help clarify
whether a ditch is a water of the United States or a point source.
Either it is a water of the United States that subjects a discharger to
sections 402 and 404 permitting requirements for direct discharges into
the ditch, or, if it is non-jurisdictional but conveys pollutants to
downstream jurisdictional waters, it may be a point source that
subjects a discharger into a ditch to section 402 permitting
requirements. Both scenarios could also be subject to statutory
exemptions that would obviate the need for a permit. In addition, if
the ditch is a non-jurisdictional water that does not convey
pollutants, it would not require a permit.
 The agencies recognize that a change in jurisdiction resulting from
this rule may change the scope of application of the CWA regulatory
programs to a particular water, but the longstanding approach that the
agencies have taken to implementing and enforcing those programs would
remain the same. If a CWA section 402 permit is not currently required
for a discharge to a water, it is unlikely that this final rule will
create a requirement for a new CWA permit. If a section 402 permit is
currently required for a discharge to a water that is no longer
jurisdictional under this final rule, that permit may no longer be
required; it may still be required if the non-jurisdictional feature
conveys a discharge of pollutants from a point source to a water of the
United States; or it may still be required but the conditions
associated with the permit may need to be modified, subject to
applicable anti-backsliding permit requirements.
 This final rule includes the agencies' longstanding interpretation
that ditches that satisfy any of the conditions of a paragraph (a)(1)
water are waters of the United States as paragraph (a)(1) waters. This
also includes tidal ditches and ditches that transport goods and
services in interstate and foreign commerce, as those ditches--more
commonly referred to as ``canals''--provide important commercial
navigation services to the nation and operate more like natural waters
traditionally understood as navigable. See, e.g., id. at 736 n.7
(Scalia, J., plurality) (``a permanently flooded man-made ditch used
for navigation is normally described, not as a `ditch,' but a `canal'
''). The Los Angeles River, for example, is a water of the United
States (having been determined to be a traditional navigable water) and
is not excluded under paragraph (b) even where it has been channelized
or concreted. Other examples include the St. Lawrence Seaway, the
Sturgeon Bay Ship Canal, and the Chesapeake and Delaware Canal.
 Under the final rule, the agencies limit the term ``waters of the
United States'' to apply to clearly defined ditches and related
features that meet the flow conditions of the ``tributary'' definition
and are not otherwise excluded. The agencies include ditches in the
``tributary'' category that were constructed in or relocated a
tributary and that continue to meet the flow conditions of the
``tributary'' definition. The final rule retains the agencies'
longstanding position that the alteration or relocation of a tributary
does not modify the jurisdictional status of that water. Accordingly,
ditches that relocate a tributary or are constructed in a tributary
would be jurisdictional as tributaries. This provision is also
consistent with the agencies' longstanding, historic position that non-
tidal ditches excavated in upland (and historically described as ``dry
land'') are not jurisdictional.
 The agencies also include ditches in the ``tributary'' category
that were constructed in a wetland that meets the definition of
``adjacent wetland,'' as long as the ditch also satisfies the flow
conditions of the ``tributary'' definition. As discussed above, this
approach aligns the rule with the CWA section 404(f) permitting
exemption for the maintenance but not construction of drainage ditches,
and the associated concern expressed during the legislative process for
the 1977 CWA amendments related to draining swamps and wetlands. The
provision is restricted to ditches that satisfy the flow conditions of
the definition of ``tributary,'' which aligns the treatment of
jurisdictional ditches with natural tributaries. See Section III.D for
a broader discussion of the ``tributary'' category.
 Ditches used to drain surface and shallow subsurface water from
cropland are a quintessential example of the interconnected
relationship between land and water resource management, as
[[Page 22298]]
is the case for managing water resources in the Western United States,
conveying irrigation water to and from fields, and managing surface
water runoff from lands and roads following precipitation events--all
activities that rely on ditches. See, e.g., FERC v. Mississippi, 456
U.S. 742, 767 n.30 (1982) (characterizing ``regulation of land use [as]
perhaps the quintessential state activity''). The majority of these
ditches will not be jurisdictional under the final rule. This final
rule therefore effectuates the clear policy directive from Congress to
preserve and protect the primary authority of States over land and
water resources within their borders. See 33 U.S.C. 1251(b), 1370.
 Commenters had differing views on the jurisdictional status of
ditches. Many commenters supported the agencies' proposed approach to
exclude many types of ditches, in particular those ditches constructed
in upland which do not relocate a tributary. Some commenters stated
that ditches should be jurisdictional even if constructed in upland if
they have perennial flow. Some commenters recommended the agencies use
the function of the ditch as the basis for an exclusion, such as all
agricultural ditches, regardless of flow. The agencies disagree with
the inclusion of upland ditches as jurisdictional waters aside from
ditches that relocate a tributary or that meet the conditions of
paragraph (a)(1). Such ditches are not part of the naturally occurring
tributary system and are not something the agencies consider to be
within their authority to regulate under the CWA. Upland ditches (other
than those ditches that relocate a tributary or that meet the
conditions of paragraph (a)(1)) do not fall under the ordinary meaning
of the term ``waters'' within the scope of the CWA. In general, upland
ditches were not jurisdictional for decades under the agencies'
previous definitions of ``waters of the United States,'' and they are
not jurisdictional under this final rule (with the exceptions noted
above). The agencies considered identifying and excluding ditches based
on the function or purpose of the ditch but concluded that such an
approach could result in the regulation of ditches with ephemeral flow
and the exclusion of ditches which are essentially relocated
tributaries. Both outcomes would be contrary to the agencies'
interpretation of the scope of CWA jurisdiction described throughout
this notice.
 The agencies recognize that there have been questions over time
about the jurisdictional status of ditches that are not maintained.
Under this final rule, a ditch constructed in an adjacent wetland that
contributes less than perennial or intermittent flow to a paragraph
(a)(1) water in a typical year and that, due to lack of maintenance,
gains wetland characteristics may be viewed as an adjacent wetland if
it meets the definition of both ``wetlands'' under paragraph (c)(16)
and ``adjacent wetlands'' under paragraph (c)(1). For example, a ditch
constructed in an adjacent wetland that abuts a tributary may have
portions that could be considered an adjacent wetland if the portions
meet the definition of ``wetland.'' Only the portion or portions of the
ditch that meets the definition of ``adjacent wetland'' are
jurisdictional under this final rule. Other ditches not constructed in
adjacent wetlands, or not otherwise covered by paragraph (a)(1) or (2),
are excluded from jurisdiction under paragraph (b)(5). Such an approach
aligns the treatment of ditches as tributaries and adjacent wetlands in
this final rule with the section 404(f) permitting exemption for the
maintenance but not construction of drainage ditches, and the
associated concern expressed during the legislative process for the
1977 amendments related to draining swamps and wetlands.
 The agencies also note that the maintenance of certain
jurisdictional ditches may occur without permitting under the section
404(f) exemptions of the CWA. Congress expressly excluded the
construction and maintenance of irrigation ditches and the maintenance
of drainage ditches (such as farm or roadside drainage ditches, many of
which are also excluded from jurisdiction under this rule) from the
permitting requirements of sections 301, 402, and 404. Discharges of
dredged or fill material associated with those exempt activities into a
ditch constructed in an adjacent wetland are therefore exempt from CWA
permitting, even if those materials are transported down the ditch to
other jurisdictional waters. The agencies note that section 404(f) has
a recapture provision that is designed to override the permitting
exemptions in section 404(f) if the otherwise exempt activity alters
the previous use of a jurisdictional water through impairment of the
circulation or flow of such waters or a reduction in the reach of such
waters. 33 U.S.C. 1344(f)(2). The agencies are aware that in some
circumstances, questions about the applicability of this recapture
provision to ditches that develop wetland characteristics have created
confusion. Some question whether the development of wetland
characteristics in a ditch establishes a new use for the water feature
such that the recapture provision overrides the ditch maintenance
exemption. This interpretation would eliminate the maintenance
exemption from performing the very purpose Congress intended--allowing
the dredging of the bottom of the ditch to eliminate obstructions to
flow, including vegetation, without the need for a permit.
 Many commenters noted that under the proposed rule, ditches must
meet the definition of ``tributary'' to be jurisdictional, but because
a ``ditch'' was defined as an artificial channel and a tributary was
``naturally occurring,'' a ditch could never meet the definition of
``tributary.'' The phrase ``naturally occurring'' does not exclude
modified natural tributaries. The final rule clarifies that the
``alteration'' or ``relocation'' of a tributary does not modify its
jurisdictional status as long as it originally occurred naturally and
continues to satisfy the flow conditions of the definition. In
addition, the agencies have clarified in the final rule that the
definition of ``tributary'' includes ditches that are constructed in or
relocate tributaries so long as the ditch satisfies the flow conditions
of the definition. A ``naturally occurring'' tributary may be altered
in such a manner that it no longer appears ``natural'' and instead has
been constructed to become a channel that conveys water. One such
example is the Los Angeles River. Such a feature may satisfy the
definition of ``ditch'' in this rule, but it also satisfies the
definition of ``tributary,'' which overrides the general exclusion for
ditches in paragraph (b)(5) as clarified in that exclusion. A ditch
that straightens a tributary is considered to be ``constructed in'' a
tributary, and the ditch would be jurisdictional as a tributary so long
as it continues to meet the flow conditions of the ``tributary''
definition.
 The proposed rule required ditches to satisfy the ``conditions'' of
the ``tributary'' definition to be jurisdictional as tributaries;
however, the agencies have clarified in the final rule that the ditches
must satisfy the flow conditions of the ``tributary'' definition to be
jurisdictional as a tributary. This requirement allows for such ditches
to be artificial (as in not ``naturally occurring'') and still be
considered tributaries. The agencies' longstanding interpretation of
the CWA is that tributaries that are altered or relocated tributaries
are jurisdictional, and the agencies are not changing this
interpretation. If a tributary is channelized, its bed and/or banks are
[[Page 22299]]
altered in some way, it is re-routed and entirely relocated, or its
flow is modified through water diversions or through other means, then
it remains jurisdictional under the final rule as long as it continues
to satisfy the flow conditions in the definition of ``tributary.''
 Finally, the agencies note that starting in the early 2000s,
certain ditches (such as roadside and agricultural ditches) have been
regarded by the Corps as jurisdictional if water from another
jurisdictional water, such as a perennial river, overflows into a ditch
and extends the ordinary high water mark of the contributing water into
the ditch. The Corps has then asserted jurisdiction over the entire
``reach'' of the ditch regardless of the location of the ordinary high
water mark in that portion of the ditch. Under this final rule, the
agencies will continue the existing practice of regulating portions of
otherwise non-jurisdictional ditches as waters of the United States
based on the ordinary high water mark of the contributing water, but
only up to the location of the ordinary high water mark, as mandated by
existing Corps regulations. The agencies will not, however, assert
jurisdiction over the entire ``reach'' of the ditch regardless of the
location of the ordinary high water mark in that portion of the ditch.
Those regulations establish the limits of jurisdiction of non-tidal
waters of the United States as extending to the ordinary high water
mark and not beyond. See 33 CFR 328.4(c). The agencies note that
continuing the practice of regulating portions of otherwise non-
jurisdictional ditches based on the ordinary high water mark of
contributing down-gradient waters will maintain better alignment with
the rule's treatment of ditches subject to the ebb and flow of the tide
as jurisdictional up to the tidal influence. It also provides some
jurisdictional commonality with the treatment of certain lakes, ponds,
and impoundments and adjacent wetlands as jurisdictional based on
inundation by flooding from other jurisdictional waters.
3. How will the agencies implement the final rule?
 The agencies have determined that in order to be jurisdictional
under this final rule, a ditch or other similar artificial feature
would first need to meet the definition of ``ditch'' (i.e., a
constructed or excavated channel used to convey water). Once a feature
has been determined to meet the definition of ``ditch,'' a ditch would
be considered a tributary where the ditch relocates a tributary, is
constructed in a tributary, or is constructed in an adjacent wetland as
long as the ditch satisfies the flow conditions of the ``tributary''
definition. The phrase ``constructed in an adjacent wetland'' refers to
ditches originating in or constructed entirely within an adjacent
wetland. The phrase also includes ditches that are constructed through
adjacent wetlands, but jurisdiction over those ditches only includes
those portions in adjacent wetlands and downstream to other
jurisdictional waters, as long as those portions satisfy the flow
conditions of paragraph (c)(12). Jurisdiction does not extend to upland
portions of the ditch prior to entry into an adjacent wetland.
Consistent with the exclusion in paragraph (b)(5), a ditch or portions
thereof may also be considered an adjacent wetland where it was
constructed in an adjacent wetland and the portion in that wetland
meets the conditions of paragraph (c)(1).
 If ditches were tributaries prior to their construction and
continue to meet the flow conditions of the ``tributary'' definition
after construction, they are jurisdictional as tributaries under the
final rule. The burden of proof lies with the agencies to demonstrate
that a ditch relocated a tributary or was constructed in a tributary or
an adjacent wetland. For example, if the agencies are not sure whether
a ditch was constructed in a tributary given the physical appearance
and functionality of the current ditch, the agencies will review the
available evidence to attempt to discern when the ditch was constructed
and the nature of the landscape before and after construction. If the
evidence does not demonstrate that the ditch was located in a natural
waterway, the ditch will be non-jurisdictional under this rule. If the
evidence suggests that the ditch may have been constructed in a natural
waterway, the agencies will review the available evidence to attempt to
discern whether that natural waterway would qualify as a tributary
under this final rule. Absent such evidence, the agencies will conclude
that the ditch is non-jurisdictional. The same methods above for
ditches constructed in a tributary apply when determining the
jurisdictional status of a ditch constructed in an adjacent wetland.
Note that under this final rule, a ditch cannot render an otherwise
isolated wetland an ``adjacent wetland'' and thus jurisdictional on
that basis, unless the ditch itself is a tributary. See Section III.G
for further discussion regarding the jurisdictional status of wetlands
under this final rule.
 Many commenters noted that historic conditions at the time of ditch
construction could be difficult to identify, and some commenters
requested more specific guidance and standards of evidence which would
be used by the agencies. Along with field data and current information
on the subject water, historic tools and resources may be used to
determine the presence of a tributary or adjacent wetland at the time
of ditch construction, and 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, local and state records and surface water management
plans, 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 ditch, this may indicate
that the 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 ditch was constructed.
 In addition, high-resolution aerial photographs may be used to
identify whether there are or were characteristics of a tributary
upstream or downstream of a ditch, indicating that a ditch may have
been constructed in or relocated a tributary. In some cases, stream
channel morphology is visible on the aerial photograph along with
visible persistent water (e.g., multiple dates of aerial photography
showing visible water) providing evidence of the flow classification
necessary to identify a tributary under this rule at the time of ditch
construction. However, characteristics of tributaries may not be
visible in aerial photographs taken in areas with high shrub or tree
cover, in which case aerial photographs or satellite imagery taken
during ``leaf off'' may provide the most beneficial information. The
burden of proof is on the agencies to determine the historic status of
the ditch construction, and if evidence does not show that the ditch
relocated a tributary, was constructed in a tributary, or was
constructed in an adjacent wetland, then a determination would be made
that the ditch is not jurisdictional under this final rule.
[[Page 22300]]
F. Lakes and Ponds, and Impoundments of Jurisdictional Waters
1. What are the agencies finalizing?
 The final rule includes a category of ``waters of the United
States'' that combines lakes, ponds, and impoundments of jurisdictional
waters into a single category. A lake, pond, or impoundment of a
jurisdictional water meets the definition of ``waters of the United
States'' if it (1) satisfies any of the conditions in paragraph (a)(1),
i.e., it is a traditional navigable water like Lake Michigan or Lake
Mead; (2) contributes surface water flow to the territorial seas or a
traditional navigable water in a typical year either directly or
through one or more jurisdictional waters; or (3) is inundated by
flooding from a paragraph (a)(1) through (3) water in a typical year. A
lake, pond, or impoundment of jurisdictional waters does not lose its
jurisdictional status if it contributes surface water flow to a
downstream jurisdictional water in a typical year through a channelized
non-jurisdictional surface water feature, through a culvert, dike,
spillway, or similar artificial feature, or through a debris pile,
boulder field, or similar natural feature.
 The agencies had proposed to include two separate categories for
lakes, ponds, and impoundments of jurisdictional waters, one for
jurisdictional lakes and ponds and another for jurisdictional
impoundments. The proposal followed the historic treatment of
jurisdictional impoundments in treating them separately as ``waters of
the United States.'' For lakes and ponds, the agencies proposed
including them as a separate waterbody-specific category for the first
time, more clearly tethering jurisdiction over those features to the
text of the statute and applicable Supreme Court guidance.
 The agencies received a wide range of public comments on the
proposed approach. Many commenters expressed support for including
lakes and ponds as a separate category, while others also supported
retaining separate treatment for impoundments of jurisdictional waters.
Other commenters suggested that because lakes, ponds, and impoundments
of jurisdictional waters are functionally similar they should be
treated as a combined category. Some commenters stated that the
proposal excluded too many lakes and ponds and said that the CWA should
apply to such features regardless of their hydrologic surface
connection to traditional navigable waters. Others argued that the
proposal asserted jurisdiction over too many lakes and ponds. Some
commenters stated that the agencies should adopt their longstanding
treatment of jurisdictional impoundments, retaining jurisdiction over
them even if they are completely disconnected from the tributary
system. Others stated that the agencies should regulate impoundments of
jurisdictional waters only if they continue to contribute flow to other
jurisdictional waters, arguing for different flow regimes (i.e.,
perennial only, perennial and intermittent, any hydrologic connection).
The agencies have considered the full range of comments and have
finalized a rule that balances these diverse viewpoints, as discussed
below, while streamlining and improving the clarity and applicability
of the rule and remaining faithful to the agencies' statutory
authorities as discussed in Section II.B.
2. Summary of Final Rule Rationale and Public Comment
 Historically, the Corps' regulations specifically defined
``lakes,'' ``ponds,'' and ``impoundments.'' In 1975, for example, the
Corps published an interim final regulation, 40 FR 31320 (July 25,
1975), that administratively defined ``lakes'' as ``natural bodies of
water greater than five acres in surface area and all bodies of
standing water created by the impounding of [waters of the United
States]. Stock watering ponds and settling basins that are not created
by such impoundments are not included.'' 40 FR 31325. In response to
the 1975 regulation, the Corps received a number of comments and
criticisms regarding the definition of ``lake.'' Some stated that the
size limitation was too small, while others stated that it was too
large. Others questioned the legality of imposing any size limitation
on natural lakes, arguing that a lake fewer than five acres in size is
as much a ``water of the United States'' as one that is more than five
acres in size. In response, the Corps established two new definitions
in 1977, one for ``natural lake'' and one for ``impoundment.'' 42 FR
37129-30 (July 19, 1977). The Corps believed the two definitions would
help alleviate confusion over the broad definition of ``lake'' provided
in 1975. In the 1977 regulation, ``natural lake'' was defined as ``a
natural depression fed by one or more streams and from which a stream
may flow, that occurs due to the widening or natural blockage of river
or stream, or that occurs in an isolated natural depression that is not
part of a surface river or stream.'' 42 FR 37144. The Corps believed
that definition reflected the three types of situations in which a
natural lake may exist. The 1977 regulation defined ``impoundment'' as
a ``standing body of open water created by artificially blocking or
restricting the flow of a river, stream, or tidal area. As used in this
regulation, the term does not include artificial lakes or ponds created
by excavating and/or diking dry land to collect and retain water for
such purposes as stock watering, irrigation, settling basins, cooling,
or rice growing.'' 42 FR 37144. No size limitation was placed on the
1977 definitions, and instead, the size limitations were used as a
distinguishing element of the CWA section 404 nationwide permit
program.
 In 1982, the Corps again published an interim final rule which
combined ``natural lake'' and ``impoundment'' into one term, ``lake.''
47 FR 31794-95 (July 22, 1982). Commenters stated that impoundments
should not be given the same status in the review process as natural
lakes; however, the Corps believed that the evaluation of the public
interest should be based on what the impacts are, and not on whether
the area in question is natural or manmade. In the 1982 regulations,
the Corps defined ``lake'' as
a standing body of open water that occurs in a natural depression
fed by one or more streams from which a stream may flow, that occurs
due to the widening or natural blockage or cutoff of a river or
stream, or that occurs in an isolated natural depression that is not
a part of a surface river or stream. The term also includes a
standing body of open water created by artificially blocking or
restricting the flow of a river, stream, or tidal area. As used in
this regulation, the term does not include artificial lakes or ponds
created by excavating and/or diking dry land to collect and retain
water for such purposes as stock watering, irrigation, settling
basins, cooling, or rice growing.
47 FR 31811. This same definition was retained when the Corps issued
its consolidated set of regulations in 1986 (51 FR 41206, November 13,
1986); however, the term ``lake'' was only retained in the part of the
regulations related to ``Permits for Discharges of Dredged or Fill
Material into Waters of the United States'' (33 CFR 323) and was not
included in the new part specifically related to the definition of
``waters of the United States'' (33 CFR 328). The definition of
``lake'' remains in the Corps' current regulation at 33 CFR 323.2(b),
and includes, ``a standing body of open water created by artificially
blocking or restricting the flow of a river, stream, or tidal area''
but excludes, ``artificial lakes or ponds created by excavating and/or
diking dry land to collect and retain water for such purposes as stock
watering, irrigation, settling basins, cooling, or rice growing.''
[[Page 22301]]
 Until this final rule, the definition of ``waters of the United
States'' has not included a separate category for lakes and ponds. To
date, the agencies viewed non-isolated ``lakes and ponds'' as
traditional navigable waters or as part of the tributary system where
they met the tributary standard. For example, if a tributary enters a
standing body of open water in a natural depression, such as a lake,
which then outlets into a downstream tributary, the lake was considered
part of the tributary system and the limits of jurisdiction were
defined by the ordinary high water mark unless adjacent wetlands were
present. Starting in the 1982 regulation, impoundments of waters
otherwise defined as ``waters of the United States'' were included as a
separate category of ``waters of the United States.'' See 40 CFR
323.2(a)(4) (1983); 47 FR 31810 (July 22, 1982). In implementing its
regulations, the Corps deemed impoundments ``waters of the United
States'' when they were created from a water of the United States,
still met another category of ``waters of the United States'' after
creation, or were isolated with a nexus to interstate or foreign
commerce.\51\
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 \51\ See the U.S. Army Corps of Engineers Jurisdictional
Determination Form Instructional Guidebook p. 58 at: https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2310.
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 In this rulemaking, the agencies proposed to maintain the
``impoundments'' category of ``waters of the United States'' as it
existed in the 1980s regulation and proposed to create a new category
for certain lakes and ponds. The agencies requested comment as to
whether a separate category was needed for impoundments of
jurisdictional waters or whether those features could be captured in
other categories of ``waters of the United States,'' such as the
proposed ``lakes and ponds'' category. The agencies received comments
in support of maintaining a separate category for impoundments, which
stated that doing so would provide clarity because it is consistent
with the agencies' longstanding practice. Commenters supporting a
separate category for impoundments also stated that impoundments are
fundamentally different from lakes and ponds and therefore should be
regulated differently. Other commenters supported combining the two
categories and stated that lakes, ponds, and impoundments function
similarly on the landscape and therefore should be regulated
consistently. These commenters also stated that the agencies do not
have legal authority to regulate impounded features that do not
otherwise satisfy the jurisdictional requirements of the CWA. Other
commenters generally found the term ``impoundment'' to be unclear and
requested that the agencies include a definition of the term in the
final rule. The agencies also requested comment on whether existing
jurisdictional impoundments could become non-jurisdictional if they
were no longer regulated as a separate category of ``waters of the
United States.'' In response, some commenters raised a concern that, if
impoundments are combined into a single category with lakes and ponds,
adjacent wetlands that are impounded could lose their jurisdictional
status.
 The agencies received comments stating that lakes and ponds should
not constitute a separate category of jurisdictional waters because
these features do not have a universally-accepted definition. Some
commenters stated that the category of lakes and ponds may be redundant
with other categories of waters, such as impoundments, and that the
extent of wetland vegetation within a shallow pond can change over
time, making it difficult to distinguish between wetland and pond
boundaries in some cases. Other commenters agreed that lakes and ponds
should comprise a separate category of jurisdictional waters to
distinguish them from other features such as tributaries and
impoundments. Commenters noted that a separate category could increase
regulatory certainty, as jurisdictional requirements may be different
for lakes and ponds as compared to other categories of waters.
 The agencies have considered these competing public comments and
for the reasons provided below are finalizing the rule with a single
category for lakes, ponds, and impoundments of jurisdictional waters.
The agencies agree with the commenters that stated lakes, ponds, and
impoundments function similarly on the landscape. The final rule is
consistent with the Corps' existing definition of ``lakes'' that
includes impoundments, although its ``lakes'' definition is not for
purposes of defining ``waters of the United States.'' See 33 CFR
323.2(b). Like lakes and ponds, many impoundments are lentic systems
(i.e., still waters) as opposed to tributaries, which are typically
lotic systems (i.e., flowing waters). In many areas of the country,
lakes and ponds exist only because rivers and other flowing features or
wetlands have been impounded. Impounded features often provide similar
commercial opportunities, water quality benefits, and wildlife habitat
as compared with natural features. Similarly, both naturally occurring
(but modified) and impounded waters and wetlands may have structures,
such as culverts, weirs, or pumps, that are designed to manage the
movement of water upstream and downstream of the structure. The
agencies conclude that because lakes, ponds, and impoundments of
jurisdictional waters generally function similarly across the
landscape, they should be regulated consistently.
 In the final rule, certain lakes, ponds, and impoundments of
jurisdictional waters are waters of the United States because these
features are waters within the ordinary meaning of the term. As
discussed in Section II.E, the plurality opinion in Rapanos stated that
the term ``the waters'' is most commonly understood to refer to ``
`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.' '' 547 U.S. at 732 (quoting
Webster's New International Dictionary 2882 (2d ed. 1954) (emphasis
added). The plurality also 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.'' Id. at 732 n.5 (emphasis added).
 Under the final rule, lakes, ponds, and impoundments that meet the
conditions to be a traditional navigable water are waters of the United
States under paragraph (a)(1) of this final rule. These waters are
discussed in more detail in Section III.B. It would be redundant to
include additional regulatory text in the lakes, ponds, and
impoundments category that declares such water features to be
jurisdictional if they satisfy the paragraph (a)(1) standard, as the
agencies had proposed for lakes and ponds. For clarity and simplicity,
the agencies are not including that cross reference in the final rule.
 The final rule focuses in large part on the lake's, pond's, or
impoundment's surface water connection to traditional navigable waters
or the territorial seas so as to remain consistent with the overall
structure and function of the CWA. See, e.g., SWANCC, 531 U.S. at 168
n.3. This final rule presents a unifying legal theory for federal
jurisdiction over waters and wetlands adjacent thereto that maintain a
sufficient surface water connection to traditional navigable waters or
the territorial seas and is supported by the legal precedent and
principles articulated in this notice. As discussed in Section II, the
agencies' authority to regulate ``the waters of the United
[[Page 22302]]
States'' is grounded in Congress' commerce power over navigation. Given
the broad purposes of the CWA, the agencies can choose to regulate
beyond waters more traditionally understood as navigable but must
provide a reasonable basis for doing so. Lakes, ponds, and impoundments
of jurisdictional waters that contribute surface water flow to
traditional navigable waters or the territorial seas in a typical year
fall within the statutory authorities delegated to the agencies by
Congress. Federally regulating these features effectuates the
objective, goals, and policies of the CWA. By contrast, the agencies
conclude that when lakes, ponds, and impoundments of jurisdictional
waters do not contribute surface water flow to a traditional navigable
water or the territorial seas in a typical year, such lakes, ponds, and
impoundments have an insufficient connection to jurisdictional waters
to warrant federal jurisdiction, unless they are inundated by flooding
from a paragraph (a)(1) through (3) water in a typical year. Regulating
these features would push the outer limits of the agencies' delegated
authorities and infringe on the powers of States to regulate their own
land and water resources and therefore are not jurisdictional under
this final rule. Through this combined category, the agencies are
incorporating common principles from the Rapanos plurality and
concurring opinions and respecting both the objective and the policy in
CWA sections 101(a) and 101(b), respectively.
 Some commenters stated that only perennial lakes, ponds, and
impoundments conveying perennial flow to a downstream paragraph (a)(1)
water should be considered ``waters of the United States.'' Other
commenters maintained that lakes, ponds, and impoundments conveying
ephemeral flow to a downstream paragraph (a)(1) water should also be
considered jurisdictional. The agencies proposed that perennial or
intermittent flow from a lake or pond to a paragraph (a)(1) water
either directly or indirectly through another jurisdictional water
could establish jurisdiction. Some commenters expressed concern that it
would be too difficult to determine the flow regime of features
connecting lakes and ponds to waters of the United States. The agencies
disagree that it would be too difficult to determine flow regime to
establish jurisdiction for lakes and ponds as proposed, as the agencies
have been using flow classifications to make jurisdictional
determinations since the 2008 Rapanos Guidance was issued. However,
upon further consideration, the agencies conclude that the proposed
rule's requirement for perennial or intermittent flow from a lake or
pond to a downstream paragraph (a)(1) water would have severed
jurisdiction for certain relatively permanent lakes and ponds that are
regularly ``connected to'' traditional navigable waters via surface
water flow. Such regular surface water flows allow such waters to
connect and become indistinguishable when flowing (i.e., they look like
one water). In the final rule, the agencies have eliminated the flow
classification requirement and instead have clarified the types of
features that can provide a sufficient surface water connection between
the lake, pond, or impoundment of a jurisdictional water and a
downstream jurisdictional water in a typical year to warrant federal
jurisdiction consistent with the CWA. This will simplify implementation
of this category.
 As discussed in Section III.A.3, the agencies have determined that
channelized non-jurisdictional ephemeral features are capable of
providing a sufficient surface water connection and that they do not
sever jurisdiction if they convey surface water flow between an
upstream relatively permanent jurisdictional water and a downstream
jurisdictional water in a typical year. In other words, an ephemeral
feature between an upstream lake and a downstream jurisdictional water
would not sever jurisdiction upstream if the ephemeral feature conveys
channelized surface water flow sufficient to allow the upstream and
downstream waters to mix in a typical year. By contrast, the agencies
conclude that diffuse stormwater run-off and directional sheet flow
over upland (non-jurisdictional features under paragraph (b)(4)) do not
provide a sufficient surface water connection to downstream
jurisdictional waters. Therefore, upstream lakes, ponds, and
impoundments that are connected to downstream jurisdictional waters
only by such flows are not jurisdictional. These types of connections
do not satisfy the limiting principles articulated in SWANCC and the
plurality and concurring opinions in Rapanos.
 Lakes, ponds, and impoundments of jurisdictional waters often
contribute surface water flow to other waters in a manner similar to a
tributary. The agencies conclude that if these features contribute
surface water flow to traditional navigable waters or the territorial
seas in a typical year, they are jurisdictional for the same reasons
that a tributary is jurisdictional. Lakes, ponds, and impoundments of
jurisdictional waters that do not contribute surface water flow to a
paragraph (a)(1) water in a typical year are not jurisdictional for the
same reasons that streams are excluded if they do not contribute
surface water flow to a paragraph (a)(1) water in a typical year. See
Section III.D of this notice for additional discussion on tributaries.
The agencies do not explicitly define ``lakes and ponds, and
impoundments of jurisdictional waters'' in paragraph (c)(6) of the
final rule to require those waters to be perennial and intermittent, as
the agencies have required for tributaries in paragraph (c)(12).
Nonetheless, ephemeral lakes, ponds, and impoundments are categorically
excluded from jurisdiction under paragraph (b)(3) of the final rule.
The key test for jurisdiction is that lakes, ponds, and impoundments of
jurisdictional waters must contribute surface water flow to a paragraph
(a)(1) water in a typical year. Waters that flow only in direct
response to precipitation do not satisfy the permanence element of the
phrase ``relatively permanent bodies of water'' and are not
jurisdictional under this final rule.
 The agencies conclude that the category of lakes, ponds, and
impoundments of jurisdictional waters in this final rule reflects the
limits of the agencies' authority that the plurality and concurring
opinions recognized in Rapanos. By requiring a contribution of surface
water flow from a lake, a pond, or an impoundment of jurisdictional
waters to a paragraph (a)(1) water in a typical year, the agencies are
establishing that a mere hydrologic connection cannot provide the basis
for CWA jurisdiction; the connection must be a surface water connection
that occurs in a typical year. Such connection to a paragraph (a)(1)
water is sufficiently frequent to warrant federal jurisdiction. This
requirement reflects the Rapanos plurality's description of a ``wate[r]
of the United States'' as ``i.e., a relatively permanent body of water
connected to traditional interstate navigable waters.'' Id. at 742
(emphasis added). It is also informed by the Rapanos plurality's
rejection of the overly broad hydrologic connection theory that the
Federal government had advanced in that case. The plurality concluded
that the phrase ``the waters of the United States'' ``cannot bear the
expansive meaning that the Corps would give it,'' id. at 732, and
rejected the notion that ``even the most insubstantial hydrologic
connection may be held to constitute a `significant nexus.' '' Id. at
728. Justice Kennedy
[[Page 22303]]
further established that ``mere hydrologic connection should not
suffice in all cases; the connection may be too insubstantial for the
hydrologic linkage to establish the required nexus with navigable
waters as traditionally understood.'' Id. at 784-85.
 An impoundment may lose its surface water connection to a
downstream jurisdictional water due to any number of reasons, including
consumptive use or evaporation or due to the structure that was
constructed to impound the water. In the proposed rule, all
impoundments of jurisdictional waters would be jurisdictional,
regardless of any surface water connection to a downstream (a)(1)
water. The agencies supported the proposed rule in part by citing the
Supreme Court's decision in S.D. Warren Co. v. Maine Board of
Environmental Protection, 547 U.S. 370 (2006), for the proposition that
impounding a jurisdictional water does not change its status as a
``water of the United States.'' 84 FR 4154, 4172 (Feb. 14, 2019),
citing S.D. Warren Co., 547 U.S. at 379 n.5. The agencies solicited
comment on the category of ``impoundments'' in the proposed rule,
including whether impoundments that release water downstream, but do so
less than intermittently, should remain jurisdictional. Some commenters
agreed that S.D. Warren Co. would authorize disconnected and isolated
impounded waters to remain jurisdictional and supported the agencies'
longstanding position that such impoundments of waters of the United
States remain jurisdictional. Other commenters stated that impoundments
that lack a surface connection to a downstream jurisdictional water
should not be waters of the United States. The agencies conclude that
an impounded water that lacks a sufficient surface water connection to
a downstream paragraph (a)(1) water in a typical year is not a water of
the United States. This interpretation of federal regulatory authority
over impoundments is most consistent with the scope of authority
granted by Congress and the legal principles articulated in Section
II.E of this notice. On further review and consideration, the agencies
observe that S.D. Warren Co. analyzes the definition of ``discharge''
in CWA section 502(16) but does not grapple with or address the subject
of this rulemaking--the definition of ``waters of the United States.''
The cited footnote in that case merely states that exerting private
control over water flow (an everyday occurrence in many parts of this
country) does not ``denationalize'' otherwise national waters. S.D.
Warren Co., 547 U.S. at 379 n.5 (``[W]e [cannot] agree that one can
denationalize national waters by exerting private control over
them.''). The case did not address what happens when a water of the
United States is so altered as to significantly modify its connection
to traditional navigable waters, nor did the cases cited in that
opinion. For example, waters of the United States are regularly
defederalized under the section 404 permitting program--in some
instances by transforming portions of traditional navigable waters for
harbor development, and jurisdictional wetlands or small tributaries to
fast land for communities and energy development, and in other
instances by cutting off or separating part of jurisdictional waters
that nonetheless remain waters, as is the case with certain causeway
construction or application of the waste treatment exclusion for
natural resource development projects. Furthermore, the agencies are
aware of no decision of the Supreme Court that has ruled that the
indelibly navigable principle applies to all waters of the United
States, although the principle does apply to certain traditional
navigable waters or any decision that would prohibit the United States
from consenting to defederalization of a water by a lawfully issued
section 404 permit. In this final rule, the agencies have defined
``waters of the United States'' not to include a water--including an
impoundment of a jurisdictional water--that lacks a sufficient surface
water connection to a downstream traditional navigable water,
consistent with the principles articulated in SWANCC. See SWANCC, 531
U.S. at 168 n.3. Impoundments of traditional navigable waters that
continue to meet the criteria in paragraph (a)(1) of this final rule
would remain jurisdictional under the CWA. S.D. Warren is not to the
contrary.
 The agencies recognize that many lakes, ponds, and impoundments of
jurisdictional waters may be connected to other jurisdictional waters
by a variety of natural and artificial non-jurisdictional features. The
agencies have specified under this final rule that lakes, ponds, and
impoundments of jurisdictional waters do not lose their jurisdictional
status if they contribute surface water flow to a downstream
jurisdictional water in a typical year through a channelized non-
jurisdictional surface water feature, through a culvert, dike,
spillway, or similar artificial feature, or through a debris pile,
boulder field, or similar natural feature. The agencies describe in
Section III.A.3 of this notice that such non-jurisdictional features do
not sever jurisdiction when surface water flow is conveyed in a typical
year, and that such flow leads to mixing between an upstream relatively
permanent jurisdictional water and a downstream jurisdictional water.
Consistent with this discussion, a non-jurisdictional feature remains
non-jurisdictional even if it provides a channelized surface water
connection between jurisdictional waters in a typical year.
 Lakes, ponds, and impoundments of jurisdictional waters that are
inundated by flooding from a paragraph (a)(1) through (3) water in a
typical year are also waters of the United States under this final
rule. See Rapanos, 474 U.S. at 732 (Scalia, J., plurality) (recognizing
that the term ``the waters'' within ``the waters of the United States''
includes ``the flowing or moving masses, as of waves or floods, making
up . . . streams or bodies'') (emphasis added) (internal quotations
omitted); id. at 770 (Kennedy, J., concurring in the judgment) (``the
term `waters' may mean `flood or inundation' events that are
impermanent by definition'') (emphasis added) (internal citations
omitted). During times of inundation by flooding from a paragraph
(a)(1) through (3) water to a lake, pond, or impoundment of
jurisdictional waters in a typical year, such a water is
indistinguishable from the jurisdictional water from which the flooding
originates.
 Inundation sufficient to establish jurisdiction occurs only in one
direction, from the paragraph (a)(1) through (3) water to the lake,
pond or impoundment of jurisdictional waters, rendering the feature
``itself a part of those waters'' ``that are `waters of the United
States' in their own right.'' Rapanos, 547 U.S. at 740, 742 (Scalia,
J., plurality). The agencies received a comment that the inundation
requirement should create jurisdiction if it occurs in either or both
directions, rather than just from a jurisdictional water to a lake,
pond or impoundment. For the reasons discussed above, the agencies have
concluded that in order to be considered part of the tributary system,
the surface water flow from a lake, pond, or impoundment of
jurisdictional waters to a paragraph (a)(1) through (3) water needs to
occur with sufficient frequency that the flow is channelized in a
typical year. Non-channelized diffuse overland flow from an otherwise
isolated waterbody lacks the indicia of permanence and sufficiency
necessary to establish jurisdiction, as described in more detail in
Section III.A.3. Mere hydrologic surface connection is not enough. Id.
at 784 (Kennedy, J., concurring in the
[[Page 22304]]
judgment). Flooding in a typical year from a paragraph (a)(1) through
(3) water to a lake, pond, or impoundment of jurisdictional waters
(that is not otherwise jurisdictional under the tests described above)
is sufficient to establish jurisdiction. That is because inundation by
flooding in a typical year makes the lake, pond or impoundment of
jurisdictional waters ``part of'' the jurisdictional water, as may
occur, for example, when an oxbow lake is located in a former channel
of a meandering river. The agencies note, however, that oxbow lakes are
not categorically jurisdictional under the final rule; to be
jurisdictional, they must satisfy one or more of the conditions of
paragraph (c)(6).
 Some commenters expressed concern that, as proposed, lakes and
ponds may be considered jurisdictional due to a single flood event in a
typical year and suggested incorporating a flood duration requirement
so that brief, infrequent floods from a paragraph (a)(1) through (3)
water would not cause a lake or pond to become jurisdictional. Under
the final rule, inundation by flooding from a paragraph (a)(1) through
(3) water to a lake, pond, or impoundment of jurisdictional waters can
occur as a result of seasonal or permanent flooding, for example, so
long as flood waters connect such waters to a paragraph (a)(1) through
(3) water in a typical year and have as their source a paragraph (a)(1)
through (3) water. The agencies are not including a minimum number of
flood events or duration of flooding that must take place in the course
of a typical year, due to the need to accommodate regional hydrological
differences. However, a mere hydrologic connection between a non-
navigable, isolated lake, pond, or impoundment and a jurisdictional
water is insufficient to establish jurisdiction under this rule. For
instance, a lake that may be connected to a water of the United States
by flooding, on average, once every 100 years is not jurisdictional. To
be jurisdictional, a lake, pond, or impoundment of jurisdictional
waters that is otherwise physically separated from a water of the
United States must be inundated by flooding from a paragraph (a)(1)
through (3) water at least once during a typical year. Oxbow lakes, for
example, may be jurisdictional under this category via inundation where
they otherwise may not satisfy the flow contribution elements of
paragraph (c)(6) of the final rule.
 The agencies have determined that an ecological connection between
physically separated lakes, ponds, and impoundments of jurisdictional
waters and other paragraph (a)(1) through (3) waters is insufficient to
assert jurisdiction over such waters. See Rapanos, 547 U.S. at 741-42
(Scalia, J., plurality) (``SWANCC found such ecological consideration
irrelevant to the question whether physically isolated waters come
within the Corps' jurisdiction.''). Some commenters requested that the
agencies eliminate a case-specific ``significant nexus'' analysis for
lakes and ponds, while other commenters supported maintaining a
``significant nexus'' analysis and identifying jurisdictional lakes and
ponds based on ecological connections to water features such as
traditional navigable waters and the territorial seas. The agencies
have concluded that the lakes, ponds, and impoundments of
jurisdictional waters category should replace existing procedures that
may depend on a case-specific ``significant nexus'' analysis of the
relationship between a particular water feature and downstream
traditional navigable waters. Lakes, ponds, and impoundments of
jurisdictional waters constitute a category of ``waters of the United
States'' that is more consistent and predictable for members of the
public and regulatory agencies to implement than a case-specific
``significant nexus'' analysis.
 The approach to lakes, ponds, and impoundments of jurisdictional
waters in this final rule is also intended to avoid ``impairing or in
any manner affecting any right or jurisdiction of the States with
respect to waters (including boundary waters) of such States.'' 33
U.S.C. 1370. For example, lakes, ponds, and impoundments of
jurisdictional waters are not waters of the United States if they do
not contribute surface water flow to a traditional navigable water in a
typical year or are not inundated by flooding from a paragraph (a)(1)
through (3) water in a typical year. Rather, they are water resources
of the States (or Tribes), and therefore States have an inherent
interest in managing such features pursuant to the powers reserved to
the States under the Constitution (and Tribes have analogous interests
as well). See., e.g., North Dakota, 127 F. Supp. 3d at 1059. States and
Tribes may therefore address such features under their own laws to the
extent they deem appropriate.
 To address comments that combining the lakes and ponds category
with impoundments could result in impounded adjacent wetlands losing
jurisdiction, the agencies have made minor modifications to the final
regulatory text from the proposal. Under the final rule, impoundments
of wetlands are jurisdictional as ``impoundments of jurisdictional
waters'' if the wetlands being impounded first meet the definition of
``adjacent wetlands'' and then meet the conditions of the lakes, ponds,
and impoundments of jurisdictional waters category. For example, under
the final rule, impounded adjacent wetlands are jurisdictional as
``impoundments of jurisdictional waters'' if they form a feature that
meets the conditions of the lakes, ponds, and impoundments of
jurisdictional waters category. That is, adjacent wetlands that are
impounded frequently become ponds and may lose their jurisdictional
status as adjacent wetlands because they no longer satisfy all three
factors of the ``wetlands'' definition. The final rule would ensure
that these waters remain jurisdictional if they satisfy the elements of
paragraph (c)(6). If those impounded wetlands, however, continue to
satisfy the definition of ``adjacent wetlands,'' they would remain
jurisdictional as adjacent wetlands. In the uncommon circumstance where
an impoundment completely severs the surface water connection between
an adjacent wetland and a jurisdictional water in a typical year, such
that the feature no longer satisfies the definition of ``adjacent
wetlands,'' the wetland would no longer be jurisdictional under this
final rule. Section III.G of this notice provides additional discussion
on adjacent wetlands.
 The agencies acknowledge that this final rule represents a change
from the agencies' longstanding practice concerning impoundments of
jurisdictional waters. Under the 2019 Rule, notwithstanding the
principles of SWANCC, impoundments of jurisdictional waters would be
jurisdictional under the separate impoundments category regardless of
any surface water connection to a downstream jurisdictional water. The
agencies now conclude that this prior interpretation is not supported
by the text, structure, or legislative history of the CWA, Supreme
Court precedent, or the foundational legal principles of this final
rule. See Section II.E. Justice Kennedy's concurring opinion also
indicates that completely isolated waters are too remote to be
regulated under the Commerce Clause powers. See 547 U.S. at 779
(Kennedy, J., concurring in the judgment) (``Nevertheless, the word
`navigable' in the Act must be given some effect. Thus, in SWANCC the
Court rejected the Corps' assertion of jurisdiction over isolated ponds
and mudflats bearing no evident connection to navigable-in-fact
waters.'' (internal citation omitted)). The
[[Page 22305]]
agencies conclude that this principle should be applied to all waters,
whether they are impoundments or not. The final rule is also consistent
with the agencies' longstanding practice that a jurisdictional water
may be altered and made non-jurisdictional by obtaining a CWA section
404 permit to place fill material in a wetland or other water, thereby
converting that water to fast land.
 Some commenters requested the agencies define the terms ``lake''
and ``pond,'' but other commenters stated that there were deficiencies
in the proposed alternatives for defining ``lakes'' and ``ponds'' such
as the definitions based on size, depth, or the Cowardin classification
system developed by the U.S. Fish and Wildlife Service. Although
regional naming conventions may vary, the agencies conclude that the
terms ``lake'' and ``pond'' are well-understood and that additional
regulatory definitions beyond what is included in the final rule are
not necessary. Rather than defining ``lakes'' and ``ponds'' based on
their geomorphology or artificial or natural status, the agencies have
instead defined surface water characteristics and conditions in
paragraph (c)(6) for purposes of establishing jurisdiction over lakes
and ponds (i.e., standing bodies of open water that contribute surface
water flow to traditional navigable waters or are inundated by flooding
from a paragraph (a)(1) through (3) water in a typical year). The same
is true for the term ``impoundment,'' which some commenters suggested
is unclear. The agencies intend the term ``impoundment,'' as it is used
in this rule and as it is used in common parlance, to mean a standing
body of open water that is formed by blocking or restricting the flow
of a pre-existing river, stream, or tidal area or by blocking or
restricting the water of a pre-existing wetland, lake, or pond. Compare
Webster's II, New Riverside University Dictionary (1994) (defining
``impound'' to mean to ``confine in'' or to ``accumulate (water) in a
reservoir''). This is generally consistent with the Corps' current
definition in 33 CFR 323.2(b) and should provide sufficient guidance
for the public to understand the regulation. An impoundment that holds
back, blocks, or restricts the flow of a water of the United States is
considered ``constructed in'' that water for purposes of this final
rule, even if portions of the impounded water also cover areas that
were originally upland or non-jurisdictional waters.
3. How will the agencies implement the final rule?
 Lakes and ponds are naturally formed through a variety of events,
including glacial, tectonic, and volcanic activity. Natural lakes and
ponds can also be subsequently modified to change surface elevation,
depth, and size. In some parts of the country these modified lakes and
ponds are referred to as impoundments, whether they impound or enlarge
an existing water of the United States or modify a non-jurisdictional
water; in other areas, these may retain lake or pond nomenclature.
Lakes, ponds, and impoundments can be man-made features constructed for
industrial and agricultural uses, power generation, domestic water
supply, or for aesthetic or recreational purposes. Many lakes, ponds,
and impoundments have at least one outflow in the form of a river,
stream, or drain which maintain a feature's surface water level or
stage by allowing excess water to discharge. Some lakes, ponds, and
impoundments do not have an outflow and lose water solely by
evaporation, underground seepage, or consumptive use. Individual lakes,
ponds and impoundments range in size. Ponds are generally smaller in
size than lakes, but regional naming conventions vary. Lakes are also
generally deeper than ponds. Like lakes and ponds, impoundments can be
large or small, deep or shallow. Some of these waters are
jurisdictional under paragraph (a)(3) of the final rule, as discussed
above, while others are non-jurisdictional, particularly many
artificial lakes and ponds pursuant to paragraph (b), as discussed in
Section III.H.
 Lakes, ponds, and impoundments are familiar types of waters that
can be easily identified by landowners; the agencies; local, State, and
tribal governments; consultants; and others. The tools discussed in
Section III.D of this notice to identify the presence of a potential
tributary can also be helpful to establish the presence of a lake,
pond, or impoundment. For example, indication of an enclosed body of
water on a USGS topographic map or certain waterbody types in the NHD
data may show that a lake, pond, or impoundment is present. USGS
topographic maps often include different symbols to indicate perennial
and intermittent lakes and ponds where such features are mapped. See
``Topographic Map Symbols,'' available at https://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf. Waterbodies such as perennial
and intermittent lakes and ponds, and reservoirs are also represented
in NHDWaterbody, where such features are mapped.\52\ The NHD portrays
the spatial geometry and the attributes of the features. However, as
the agencies recognize in Section IV, these tools were not designed to
indicate the jurisdictional status of waters of the United States, and
limitations associated with these maps and data sets may require field-
verification for accuracy.
---------------------------------------------------------------------------
 \52\ See ``Complete FCode list for NHD Hydrography Features,''
available at https://nhd.usgs.gov/userGuide/Robohelpfiles/NHD_User_Guide/Feature_Catalog/Hydrography_Dataset/Complete_FCode_List.htm.
---------------------------------------------------------------------------
 After identifying a lake, pond, or impoundment, the next step is to
determine whether the lake, pond, or impoundment meets the conditions
of a paragraph (a)(1) water under the final rule and would therefore be
regulated under that category. Consistent with the agencies'
longstanding regulation and practice, paragraph (a)(3) waters do not
include impoundments of non-jurisdictional waters. If an impoundment
does not meet the conditions of a paragraph (a)(1) water, then the
agencies must establish whether the feature is an impoundment of a
jurisdictional water. The agencies may use historical and current
sources of information such as construction plans, permit records,
aerial photography, maps, and remote sensing data, as well as
topographic information or relevant field data from site visits, to
determine whether an impoundment was created by impounding a
jurisdictional water such as a tributary or adjacent wetland. In making
a jurisdictional determination under this rule, the agencies would
evaluate the open body of water or wetland.\53\
---------------------------------------------------------------------------
 \53\ The agencies note that the construction of a physical
structure that impounds a body of water (e.g., a dam, berm, or weir)
may require a CWA section 404 permit (e.g., when a discharge of
dredged or fill material into a jurisdictional water occurs during
construction of the impounding structure), in addition to other
authorizations which may be required, such as a RHA section 9 or
section 10 permit.
---------------------------------------------------------------------------
 If a lake, pond, or impoundment of a jurisdictional water does not
meet the conditions of a paragraph (a)(1) water, then the agencies
would determine whether the water directly or indirectly contributes
surface water flow to a paragraph (a)(1) water in a typical year, or is
inundated by flooding from a paragraph (a)(1) through (3) water in a
typical year. The agencies could use similar sources of information
indicating the existence of a lake, pond, or impoundment to determine
whether the water feature contributes surface water flow to a paragraph
(a)(1) water in
[[Page 22306]]
a typical year. Many commenters requested that the agencies identify
specific sources of information that would be used to determine whether
lakes, ponds, and impoundments contribute surface water flow to a water
of the United States. A combination of the tools and other resources
described in Section III.D.3 may be used to establish jurisdiction of a
lake, pond, or impoundment. For instance, if utilizing the NHD,
waterbodies that are classified as a lake/pond or a reservoir in the
dataset may have NHDFlowline artificial paths represented as flowing
through them to complete a stream network and as a surrogate for
general water flow direction. Combining this information with site
visits, climate data, and surrounding hydrology data can yield greater
certainty as to the presence of a lake, pond, or impoundment, and as to
whether the feature contributes surface water flow to a downstream
paragraph (a)(1) water in typical year. These tools may also be helpful
in indicating whether a lake, pond, or impoundment of a jurisdictional
water is part of the tributary network of a paragraph (a)(1) water. For
example, the presence of a ``blue line stream'' on USGS topographic or
NHD maps which extends from the feature may indicate that the lake,
pond, or impoundment contributes surface water flow, directly or
indirectly through a paragraph (a)(2) through (4) water, to a paragraph
(a)(1) water in a typical year, which may indicate that the feature is
jurisdictional. Other complementary data sources that can be used in
conjunction with maps to determine the potential jurisdictional status
of a lake, pond, or impoundment of a jurisdictional water include gage
data, bathymetry data, elevation data, spillway height, historic water
flow records, flood predictions, statistical evidence, aerial
photographs, remote sensing data, and hydrologic and non-hydrologic
field observations.
 A lake, pond, or impoundment of a jurisdictional water does not
lose its jurisdictional status if it contributes surface water flow to
a downstream jurisdictional water in a typical year through a
channelized non-jurisdictional surface water feature; through a
culvert, dike, spillway, or similar artificial feature; or through a
debris pile, boulder field, or similar natural feature. Under the final
rule, the agencies have determined that lakes, ponds, and impoundments
of jurisdictional waters may be jurisdictional if they have a
channelized surface water connection to a paragraph (a)(1) water in a
typical year. To determine the existence of channelized non-
jurisdictional surface water features (e.g., ephemeral streams or non-
jurisdictional ditches), culverts, dikes, spillways, or similar
artificial features, or debris piles, boulder field, or similar natural
features, the agencies may use remote sensing data, aerial photography,
and field observations. The agencies may also rely on elevation data,
aerial photography, remote sensing data, hydrologic models, flow data,
field indicators, operation records, and visual observations to
determine whether flow likely occurs through these non-jurisdictional
water features in a typical year.
 Lakes, ponds, and impoundments of jurisdictional waters that are
inundated by flooding from a paragraph (a)(1) through (3) water in a
typical year are also waters of the United States under this rule.
Commenters noted that field observations, sometimes based on multiple
site visits, may be necessary to determine that a surface water
connection exists for lakes and ponds as a result of flooding from a
traditional navigable water, tributary, or other jurisdictional lake or
pond, or jurisdictional impoundment. Many commenters also stated that
establishing a surface water connection based on inundation from a
paragraph (a)(1) through (3) water to a lake or pond in a typical year
may be difficult to implement. The agencies disagree with this
suggestion as they are frequently asked to complete jurisdictional
determinations when surface water connections are not present. In these
cases, the agencies have used a variety of data sources that do not
depend on visual observations of inundation, including but not limited
to flood records, precipitation data, elevation data, aerial
photography, remote sensing data, and hydrologic models. The agencies
will complement remote tools with hydrologic and non-hydrologic field
observations when necessary to determine the presence of a
jurisdictional lake, pond, or impoundment due to inundation by flooding
from a paragraph (a)(1) through (3) water.
 The agencies recognize that artificial features such as a dike or
berm could prevent a lake or pond from releasing surface water
downstream to a water of the United States in a typical year.
Similarly, a dam could prevent an impounded water from releasing
surface water downstream to a water of the United States in a typical
year. Under the final rule, lakes, ponds, and impoundments of
jurisdictional waters are jurisdictional if they meet the conditions of
paragraph (c)(6), including contributing surface water flow to a
downstream jurisdictional water in a typical year. Such contribution
could occur through pumps, flood gates, reservoir releases, or other
mechanisms. The agencies do not distinguish between natural and
artificially-manipulated surface water flow that connects a lake, pond,
or impoundment with another water of the United States in a typical
year. Furthermore, if an artificial feature such as a dike or dam
causes a channelized downstream perennial or intermittent feature to
become ephemeral, that channelized ephemeral feature would be non-
jurisdictional under paragraph (b)(3) but would not sever jurisdiction
of upstream features as long as it conveys surface water flow in a
typical year to a downstream paragraph (a)(1) water.
 In Section III.A.1 of this notice, the agencies describe a variety
of methods and data sources that could be used to determine whether
conditions meet the definition of ``typical year.'' For instance, the
agencies have developed and utilized a method for determining normal
precipitation conditions. The agencies currently use professional
judgment and a weight of evidence approach as they consider
precipitation normalcy along with other available data sources. The
agencies recognize the need to consider seasonality and timing of
surface water connections in utilizing the data sources described above
and determining whether lakes, ponds, and impoundments meet the
conditions of paragraph (c)(6) in the final rule. For example, a lake,
pond, or impoundment of a jurisdictional water may be inundated by
flooding from a paragraph (a)(1) through (3) water only during
seasonally wet conditions. If the agencies complete a jurisdictional
determination during seasonally dry conditions and do not visually
observe inundation, they may use the multiple tools described above,
including remote- and field-based hydrologic and non-hydrologic
indicators, to determine whether inundation from flooding would
typically occur during seasonally wet conditions.
 A few commenters discouraged the agencies from relying solely on
one source of data and recommended that mapping sources should be
paired with remote sensing and field verification data. As described
above, the agencies encourage the use of multiple complementary data
sources to establish the presence of lakes, ponds, and impoundments and
to determine their jurisdictional status. For example, waterbody and
flowline features in the NHD could be used to determine the
[[Page 22307]]
likelihood of an existing lake, pond, or impoundment that has a direct
or indirect surface water connection to a paragraph (a)(1) water. A
site visit could then confirm the existence of the lake, pond, or
impoundment, and aerial photography and physical field indicators or
local knowledge could establish the likelihood of recent inundation.
Finally, the agencies could determine whether climatic conditions meet
the definition of ``typical year'' using, for example, the method for
determining normal precipitation conditions described in Section
III.A.1 of this notice, combined with other relevant sources of
information such as the Palmer Drought Severity Index. Many commenters
noted that the availability of data records and tools may vary across
the country. The agencies have determined that the information provided
by the tools described herein and other available information will vary
in availability and accuracy in different parts of the country, and
will take that into account when utilizing their expert judgment in
evaluating the information prior to determining the jurisdictional
status of a lake, pond, or impoundment of a jurisdictional water.
 Some commenters asked whether features could simultaneously be
excluded from regulation as artificial lakes and ponds, but also meet
the definition of jurisdictional impoundments. As discussed in Section
III.H of this notice, paragraph (b)(8) of the final rule specifies that
the artificial lakes and ponds exclusion does not apply to
jurisdictional impoundments. An artificial lake or pond will be
excluded even if it satisfies the definition in paragraph (c)(6), so
long as it was constructed or excavated in upland or in non-
jurisdictional waters and is not a jurisdictional impoundment. In other
words, paragraph (b)(8) is designed to exclude artificial lakes and
ponds that are constructed in upland or non-jurisdictional waters, even
where they may have a surface water connection to a downstream
jurisdictional water in a typical year.
G. Adjacent Wetlands
1. What are the agencies finalizing?
 The agencies are finalizing a category of ``waters of the United
States'' to include all adjacent wetlands to: The territorial seas and
traditional navigable waters (paragraph (a)(1) waters); tributaries to
those waters (paragraph (a)(2) waters); and lakes, ponds, and
impoundments of jurisdictional waters (paragraph (a)(3) waters). In
this final rule, the agencies define the term ``adjacent wetlands'' to
mean wetlands that: (1) Abut a paragraph (a)(1) through (3) water; (2)
are inundated by flooding from a paragraph (a)(1) through (3) water in
a typical year; (3) are physically separated from a paragraph (a)(1)
through (3) water only by a natural berm, bank, dune, or similar
natural feature; or (4) are physically separated from a paragraph
(a)(1) through (3) water 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
paragraph (a)(1) through (3) water in a typical year, such as through a
culvert, flood or tide gate, pump, or similar artificial feature. Under
the final rule, an adjacent wetland is jurisdictional in its entirety
when a road or similar artificial structure (i.e., not naturally
occurring) divides the wetland, as long as the structure allows for a
direct hydrologic surface connection through or over that structure in
a typical year.
 By retaining the term ``adjacent'' in the definition from the
longstanding regulations, the agencies are continuing to use
terminology that is familiar to the agencies and the regulated public.
As proposed, however, the agencies are not including the terms
``bordering, contiguous, or neighboring'' from the previous regulations
to reduce the potential confusion associated with using three seemingly
similar terms in the same definition. See, e.g., U.S. General
Accounting Office, Waters and Wetlands, GAO-04-297, at 10 (Feb. 2004)
(``The regulations specify that adjacent means `bordering, contiguous,
or neighboring'. . . . This definition of adjacency leaves some degree
of interpretation to the Corps districts.''); see also id. at 3
(``Districts apply different approaches to identify wetlands that are
adjacent to other waters of the United States and are subject to
federal regulation.''). Instead, the agencies use the term ``abut'' to
clearly identify those waters that are inseparably bound up with other
jurisdictional waters, in addition to the other clear tests for
adjacency in this final rule.
 The final rule adopts categorical tests for adjacency that are like
those included in the proposal, but upon consideration of the public
comments received, the agencies have enhanced the final definition to
improve its clarity and ease of implementation, and to include
additional wetlands that, upon further consideration, the agencies
conclude should be subject to federal jurisdiction. Like the proposal,
adjacent wetlands are those that abut or otherwise have a direct
hydrologic surface connection to other covered waters in a typical
year. But the agencies have modified the test to maintain jurisdiction
over wetlands separated from other jurisdictional waters only by
natural berms, banks, or dunes as those natural separations are
evidence of a dynamic and regular direct hydrologic surface connection
between the resources based on the agencies' technical expertise and
experience. The agencies have also simplified and expanded the type of
surface water connections that are not jurisdictional themselves but
can nevertheless maintain jurisdictional connectivity between wetlands
and other waters of the United States that are separated only by
artificial dikes and other barriers. The agencies have also expanded
jurisdiction, as compared to the proposal, over wetland complexes that
are crossed by roads and similar structures if those structures allow
for a surface water connection between the segregated wetland portions
(such as through a culvert through a roadway) in a typical year.
 Many commenters supported the proposal as establishing an
appropriate balance between Federal and State jurisdiction over
wetlands. Others stated that the proposal regulated too broadly. Still
others asserted that the proposal too narrowly interpreted the
agencies' CWA authorities and restricted jurisdiction over many
ecologically important wetlands. The agencies have considered the
diverse range of comments and are finalizing a rule that results in a
balance of these competing views while adhering to the agencies'
delegated authorities under the CWA and avoiding the outer limits of
such authority.
 Like the proposed rule, this final rule maintains the longstanding
regulatory definition of ``wetlands'' in paragraph (c)(16) 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. Wetlands generally
include swamps, marshes, bogs, and similar areas.'' This is a well-
established definition that is familiar to regulators, environmental
consultants, and the scientific community. The agencies received many
public comments urging them to maintain this definition, while certain
other commenters suggested the agencies adopt different formulations.
In this final rule, the agencies have retained the longstanding
definition unchanged, as proposed.
[[Page 22308]]
 Consistent with the proposal, the agencies are finalizing a
definition of ``upland'' to mean any land area above the ordinary high
water mark or high tide line that does not satisfy all three wetland
factors (i.e., hydrology, hydrophytic vegetation, and hydric soils
\54\) under normal circumstances, as described in the Corps' 1987
Wetlands Delineation Manual. Features that were once wetlands but have
been naturally transformed or lawfully converted to upland (e.g., in
compliance with a CWA section 404 permit) are considered upland under
the final rule. For convenience, the agencies are including the
existing Corps definitions for ``ordinary high water mark'' and ``high
tide line'' from 33 CFR 328.3 in the EPA's regulations, as those terms
are used in the final definition of ``upland.''
---------------------------------------------------------------------------
 \54\ See Corps' 1987 Wetlands Delineation Manual at 9-10
(``Wetlands have the following general diagnostic environmental
characteristics: (1) Vegetation. The prevalent vegetation consists
of macrophytes that are typically adapted to areas having hydrologic
and soil conditions . . . Hydrophytic species, due to morphological,
physiological, and/or reproductive adaptation(s), have the ability
to grow, effectively compete, reproduce, and/or persist in anaerobic
soil conditions. . . . (2) Soil. Soils are present and have been
classified as hydric, or they possess characteristics that are
associated with reducing soil conditions. . . . (3) Hydrology. The
area is inundated either permanently or periodically at mean water
depths https://www.epa.gov/npdes/interpretative-statement-releases-pollutants-point-sources-groundwater.
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Ephemeral Features and Diffuse Stormwater Run-Off
 In paragraph (b)(3), the final rule excludes ephemeral features,
including ephemeral streams, swales, gullies, rills, and pools. In
paragraph (b)(4), the rule excludes diffuse stormwater run-off and
directional sheet flow over upland. Such features are not
jurisdictional under the terms of paragraph (a) in the final rule or
its definitions in paragraph (c). They are specifically excluded in the
final rule for additional clarity. The final rule differs from the
proposed rule, as (b)(3) and (b)(4) were combined into one category of
exclusions in the proposal. The agencies believe that separating the
exclusions into two categories, as they have done for the final rule,
provides greater clarity. The separation does not have a practical
effect on or substantively change the types of waters and features that
the final rule excludes compared to the proposed rule. As described in
detail in Section III.A.3, the agencies have revised the proposed rule
to clarify that while ephemeral features are not waters of the United
States, a tributary does not lose its jurisdictional status if it
contributes surface water flow to a downstream jurisdictional water in
a typical year through a channelized ephemeral feature, such as an
ephemeral stream or gully. However, if an upstream reach is connected
to the downstream reach only by diffuse stormwater runoff or
directional sheet flow over upland, the upstream reach is not
jurisdictional under the final rule. Providing additional clarity in
the paragraph (b) exclusions helps to highlight that only some excluded
features are capable of providing a channelized surface water
connection between upstream and downstream perennial or intermittent
waters. Under the final rule, ephemeral features are not jurisdictional
and do not become jurisdictional even if they maintain jurisdiction of
relatively permanent upstream waters by conveying surface water from
those waters to downstream jurisdictional waters in a typical year.
 Some commenters supported the ephemeral features exclusion as being
consistent with the CWA, Commerce Clause, and case law, particularly
the plurality opinion in Rapanos. For example, one commenter indicated
that the proposed exclusion aligned with CWA section 101(b) and, by
avoiding jurisdiction over primarily dry features, did not
significantly alter the Federal-State framework. Other commenters
expressed concern that if they are not jurisdictional, ephemeral
features could be subject to uncontrolled pollution or filled, and some
commenters emphasized the potential adverse impacts to downstream
jurisdictional waters into which ephemeral features flow.
 By defining perennial and intermittent tributaries of traditional
navigable waters as jurisdictional and defining ephemeral features as
non-jurisdictional, and by including (b)(3) and (b)(4) exclusions
explicitly emphasizing the non-jurisdictional status of ephemeral
features and diffuse stormwater run-off, the agencies are balancing
Congress' intent to interpret the term ``navigable waters'' more
broadly than the classical meaning of that term and the notion that
nothing in the legislative history of the Act ``signifies that Congress
intended to exert anything more than its commerce power over
navigation.'' SWANCC, 531 U.S. at 168 n.3. The exclusions in paragraphs
(b)(3) and (b)(4) and the final rule's limitation of jurisdiction to
perennial and intermittent rivers and streams most appropriately
balances the Federal government's interest in regulating the nation's
navigable waters with respecting State and Tribal land use authority
over features that are only episodically wet during and/or following
precipitation events. See, e.g., Rapanos, 547 U.S. at 734 (Scalia, J.,
plurality) (identifying ``ephemeral streams'' and ``directional sheet
flow during storm events'' as beyond the scope of CWA jurisdiction).
 Some commenters raised concerns with potential adverse impacts to
downstream jurisdictional waters from discharges to non-jurisdictional
ephemeral features. The agencies believe that a CWA section 402
permittee currently discharging to a jurisdictional water that becomes
non-jurisdictional under this final rule would likely remain subject to
the requirements of the Act. This specific concern was raised in
Rapanos, that enforcement of section 402 could be frustrated by
``polluters . . . evad[ing] permitting requirement . . . by discharging
their pollutants into noncovered intermittent watercourses that lie
upstream of covered waters.'' Id. at 742-43. In the words of Justice
Scalia, ``That is not so.'' Id. New or continuing discharges, whether
illicit or not, could be subject to sections 301 and 402 of the Act if
the discharge is conveyed from a point source to a ``water of the
United States.'' The agencies view ephemeral features, such as arroyos
or ditches, as potential conveyances of discharges of pollutants from
point sources subject to NPDES permitting requirements. So too, the
agencies believe, did Justice Scalia. He referred to ``channels''--a
term used in the definition of ``point source'' at 33 U.S.C. 1362(14)--
as ``ephemeral streams,'' ``dry arroyos in the middle of the desert,''
and ``manmade drainage ditches'' when characterizing the types of
features that he believed stretched the meaning of the ``term `waters
of the United States' beyond parody.'' Id. at 734. Additional
discussion of the final rule's treatment of ephemeral features is
provided in Section III.A.3 of this notice.
Ditches
 The final rule's ditch exclusion in paragraph (b)(5) is intended to
provide greater clarity for the regulated public and to be more
straightforward for agency staff to implement than current practice.
The agencies have incorporated a clear statement in the final rule that
all types of ditches would be excluded except where they meet the
conditions of paragraph (a)(1) or (2) of the final rule or where, in
limited instances, they meet the conditions of paragraph (c)(1).
Further, as discussed in Section III.D and Section III.E of this
notice, the final rule clarifies that ditches are tributaries under
paragraph (a)(2) where they relocate a tributary, are constructed in a
tributary, or are constructed in an adjacent wetland, so long as the
ditch satisfies the flow conditions of the ``tributary'' definition.
Many States, regional groups, and national associations that commented
during the Federalism consultation as part of development of the
proposed rule and during the agencies' general outreach efforts noted
that the definition of ``waters of the United States'' should exclude
ditches. The agencies received further comments on the proposed rule's
category of jurisdictional ditches and the exclusion for all other
ditches. Some commenters argued that all ditches should be
jurisdictional if they convey any volume of water to a covered water,
however infrequent or insubstantial, while others took the opposite
view. As discussed in Sections III.D. and III.E., the approach adopted
in this final rule reasonably balances the exclusion of features that
are fundamental to State, tribal, and local land use planning while
respecting the need to preserve jurisdiction over certain ditches.
[[Page 22320]]
Prior Converted Cropland
 The agencies are finalizing the prior converted cropland exclusion
in paragraph (b)(6) and adding a definition of ``prior converted
cropland'' in paragraph (c)(9). The definition of ``prior converted
cropland'' clarifies that the exclusion is no longer applicable when
the cropland is abandoned and the land has reverted to wetlands, as
that term is defined in paragraph (c)(16). Under this final rule, prior
converted cropland is considered abandoned if it is not used for, or in
support of, agricultural purposes at least once in the immediately
preceding five years. Agricultural purposes include land use that makes
the production of an agricultural product possible, including but not
limited to grazing and haying. Additional discussion on agricultural
purposes is provided below. This final rule also clarifies that
cropland that is left idle or fallow for conservation or agricultural
purposes for any period or duration of time remains in agricultural use
(i.e., it is used for, or in support of, agriculture purposes), and
therefore maintains the prior converted cropland exclusion. The
agencies conclude that this clarification will ensure that cropland
enrolled in long-term and other conservation programs administered by
the Federal government or by State and local agencies that prevents
erosion or other natural resource degradation does not lose its prior
converted cropland designation as a result of implementing conservation
practices.
 In 1993, the agencies categorically excluded prior converted
cropland from the definition of ``waters of the United States.'' 58 FR
45034-36 (August 25, 1993). As further explained below, in keeping with
the Food Security Act of 1985 (FSA), the 1993 preamble defined 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 [and that are]
inundated for no more than 14 consecutive days during the growing
season.'' 58 FR 45031. As explained in detail in the 1993 preamble, due
to the degraded and altered nature of prior converted cropland, the
agencies determined that such lands should not be treated as
jurisdictional wetlands for purposes of the CWA because regulating such
lands does not further the objective of the Act. 58 FR 45032. The 1993
preamble also set out a mechanism to ``recapture'' prior converted
cropland into the section 404 program when the land has been abandoned
and wetland features return. 58 FR 45034. This approach is consistent
with the principles in the 1990 Corps Regulatory Guidance Letter 90-7.
Although included in the 1993 preamble and Regulatory Guidance Letter
90-7, these principles have not been incorporated into the text of any
promulgated rule until now. This rule therefore represents the first
time the agencies are promulgating regulatory language to clarify the
meaning of ``prior converted cropland'' for CWA purposes, the
application of the exclusion, and a recapture mechanism based on
abandonment and reversion to wetlands.
 Historically, the agencies have attempted to create consistency
between the CWA and the FSA wetlands conservation provisions for prior
converted cropland. The agencies continue to believe that consistency
across these programs is important for the regulated community (see 58
FR 45033), and therefore are continuing to exclude prior converted
cropland from the definition of ``waters of the United States.'' By
incorporating the abandonment principles from the 1993 preamble and
providing examples of ``agricultural purposes,'' this final rule
remains consistent with the concepts underlying the FSA but differs in
implementation from certain aspects of USDA's current wetlands
compliance authority. Incorporating the abandonment principle, as
opposed to a pure ``change in use'' policy (described below), is
important for the agencies to appropriately manage certain wetland
resources while providing better clarity to the agricultural community.
 When the 1993 preamble was published, the abandonment principle was
consistent with USDA's implementation of the FSA. Three years later,
the 1996 FSA amendments modified the abandonment principle and
incorporated a ``change in use'' policy. See Public Law 104-127, 110
Stat. 888 (1996). Under the new policy, prior converted cropland would
continue to be treated as such even if wetland characteristics returned
because of lack of maintenance of the land or other circumstances
beyond the owner's control, ``as long as the prior converted cropland
continues to be used for agricultural purposes.'' H.R. 2854, Conf. Rep.
No. 104-494, at 380 (1996). In 2005, the Corps and NRCS issued a joint
``Memorandum to the Field'' (the 2005 Memorandum) in an effort to again
align the CWA section 404 program with the FSA by adopting the amended
FSA's change in use policy. The 2005 Memorandum provided that, a
``certified [prior converted] determination made by [USDA] 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 cropland]
determination is no longer applicable, and a new wetland determination
is required for CWA purposes.'' \57\
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 \57\ Memorandum to the Field on Guidance on Conducting Wetland
Determinations for the Food Security Act of 1985 and section 404 of
the Clean Water Act, February 25, 2005, available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2508.
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 The 2005 Memorandum did not clearly address the abandonment
principle that the agencies had been implementing since the 1993
rulemaking. The change in use policy articulated in the 2005 Memorandum
was also never promulgated as a rule and was declared unlawful by one
district court because it effectively modified the 1993 preamble
language without any formal rulemaking process. See New Hope Power Co.
v. U.S. Army Corps of Eng'rs, 746 F. Supp. 2d 1272, 1282 (S.D. Fla.
2010). Implementing the 2005 Memorandum created other challenges for
the agencies and the regulated community. For example, because the 2005
Memorandum did not clearly address whether or how the abandonment
principles should be applied in prior converted cropland cases, neither
the agencies nor the regulated community could be certain which
approach would be applied to a specific case.
 The agencies received many public comments on the prior converted
cropland exclusion, with some commenters noting that the exclusion will
provide clarification needed to protect prior converted cropland that
may be subject to flooding and to other natural occurrences that result
in wet or saturated fields. The agencies also received public comments
on both the abandonment principle and the change in use analysis. Some
commenters supported the abandonment principle, stating, for example,
that prior converted cropland should lose its status only when the land
is abandoned and the area reverts back to wetland. Other commenters
requested that the agencies finalize the change in use analysis, as
articulated in the 2005 Memorandum. The agencies have considered these
comments and for the reasons provided herein are finalizing the
abandonment principle as proposed and are not adopting the change in
use approach.
 The agencies received many comments in support of the term ``for or
in support of, agricultural purposes'' and recommendations as to how
the term should be interpreted. Commenters
[[Page 22321]]
requested that the agencies provide additional examples of agricultural
purposes, including, but 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. The uses listed above, in addition to crop production, haying,
and grazing, fall within the term ``agricultural purposes'' and, if
documented, may maintain the prior converted cropland exclusion.
Conservation practices, including those required or supported by USDA,
State, and local programs (including recognized private sector programs
that partner with government programs or that can provide verifiable
documentation of participation) are critical to the success of
agricultural systems across the country. Conservation practices and
programs also are conducted ``for or in support of agricultural
purposes'' and are appropriate to maintain the prior converted cropland
exclusion.
 The agencies also received public comment on the type of
documentation that a landowner should maintain to demonstrate that
cropland has been used ``for or in support of, agricultural purposes.''
Commenters suggested the use of aerial photographs, topographical maps,
cultivation maps, crop expense or receipt records, field- or tract-
specific grain elevator records, and other records generated and
maintained in the normal course of doing business. The agencies agree
that these types of documents and other documentation reasonably
establishing ``agricultural purposes'' are appropriate to demonstrate
that the prior converted cropland exclusion applies to a certain field
or tract of land.
 Finally, the agencies received public comments on whether the five-
year timeframe for maintaining agricultural purposes is appropriate.
Some commenters supported the five-year timeframe. Other commenters
thought that five years was too long to avoid federal jurisdiction if
wet cropland was providing some ecological or habitat benefit that
should be maintained. Other commenters thought that the five-year
timeframe was too short to account for unforeseen circumstances that
could leave cropland idle for longer periods of time (e.g., bankruptcy,
the probate and estate administration process, natural disasters), and
recommended that the agency adopt a seven, ten, or twenty-year
timeframe. Some commenters specifically requested that the agencies
allow more than five years when drought or flood conditions prevent
cultivation, planting or harvest. The agencies have considered these
comments and conclude that a five-year timeframe for maintaining
agricultural purposes is reasonable and consistent with the 1993
preamble (58 FR 45033) and with the five-year timeframe regarding
validity of an approved jurisdictional determination (2005 Corps
Regulatory Guidance Letter (RGL) 05-02). The five-year timeframe is
longstanding in the CWA section 404 program and will be familiar to
landowners and regulators alike, increasing clarity in implementation.
The agencies are finalizing the rule with the five-year timeframe, as
proposed, but as described in the next subsection, the agencies will
work closely with USDA, and will consider documentation from USDA,
NOAA, FEMA, or other Federal or State agencies to determine if the land
was used for or in support of agricultural purposes in the immediately
preceding five years to evaluate whether cropland has in fact been
abandoned.
 The agencies consider rulemaking to be appropriate here in order to
clarify the definition of ``prior converted cropland'' and to provide
regulatory certainty over when such lands are no longer eligible for
the CWA exclusion. This final rule provides much needed clarity about
the prior converted cropland exclusion and how wetlands can be
recaptured into CWA jurisdiction through the abandonment test. In
addition to finalizing the exclusion as proposed, the Corps will
withdraw the 2005 Memorandum simultaneous with the effective date of
this rule.
Artificially Irrigated Areas, Artificial Lakes and Ponds, and Water-
Filled Depressions
 Paragraph (b) also excludes from waters of the United States under
this final rule:
 Artificially irrigated areas, including fields flooded for
agricultural production, that would revert to upland should application
of irrigation water to that area cease (paragraph (b)(7));
 Artificial lakes and ponds, including water storage
reservoirs and farm, 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 conditions of paragraph (c)(6)
(paragraph (b)(8)); and
 Water-filled depressions constructed or excavated in
upland or in non-jurisdictional waters incidental to mining or
construction activity, and pits excavated in upland or in non-
jurisdictional waters for the purpose of obtaining fill, sand, or
gravel (paragraph (b)(9)).
 Paragraphs (b)(7), (8), and (9) of the final rule identify features
and waters that the agencies have generally excluded from the
definition of ``waters of the United States'' in previous preambles
since 1986 (see, e.g., 51 FR 41206, 41217 (November 13, 1986) and 53 FR
20764-65 (June 6, 1988)). The agencies have codified these longstanding
exclusions to further the agencies' goals of providing greater clarity
and predictability for the regulated public and the regulators.
 Several of these exclusions use the phrase ``upland.'' In keeping
with the goal of providing greater clarity, the agencies have included
in the final rule a definition of ``upland'' in paragraph (c)(14). It
is important to note that a water of the United States is not
considered ``upland'' just because it lacks water at a given time.
Similarly, an area may remain ``upland'' even if it is wet sporadically
or after a rainfall or flood event. In addition, the agencies recognize
that excluded water features may be constructed or excavated in non-
jurisdictional ponds, wetlands, or other non-jurisdictional features.
Therefore, the agencies added the phrase ``non-jurisdictional waters''
to some of these exclusions to provide greater clarity and to confirm
that these features can be constructed or excavated in a non-
jurisdictional water, such as an isolated pond or wetland, while
continuing to be excluded from federal jurisdiction.
 The upland requirement does not apply to all exclusions under
paragraph (b). For those waters or features in paragraph (b) of this
final rule that do contain the stipulation that they must be
constructed or excavated in upland or in non-jurisdictional waters to
be excluded, the agencies intend that these features be constructed or
excavated wholly in upland or in non-jurisdictional waters. For
example, construction activities that enlarge a water of the United
States beyond its current boundaries are not constructed wholly in
upland. Where portions of a new or modified water feature are built in
a jurisdictional water, the agencies would not view the new or modified
feature as having been constructed or excavated wholly in upland or in
non-jurisdictional waters, and therefore not subject to the exclusion.
But where a stock watering pond, for example, is developed in a spring
that is non-jurisdictional under this final rule, that pond will be
considered by the agencies to have been constructed wholly in
[[Page 22322]]
upland and/or non-jurisdictional waters. Even if a feature is not
constructed or excavated wholly in upland or in non-jurisdictional
waters and meets the definition of ``waters of the United States,'' it
may be otherwise excluded under another part of paragraph (b). The
agencies note, however, that the mere interface between the excluded
feature constructed or excavated wholly in upland and a jurisdictional
water does not make that feature jurisdictional. For example, a ditch
constructed or excavated wholly in upland that connects to a tributary
would not be considered a jurisdictional ditch. The connection to a
jurisdictional water does not eliminate applicability of a paragraph
(b) exclusion conditioned by the upland or non-jurisdictional waters
language. To avoid any confusion in implementation, this is why the
agencies have not included the term ``wholly'' in the final regulatory
text. Finally, an excluded feature under the final rule that develops
wetland characteristics within the confines of the non-jurisdictional
water or feature remains excluded from the definition of ``waters of
the United States,'' with the exception in limited circumstances of
wetlands that develop in ditches constructed in adjacent wetlands, as
discussed in Section III.G.
 Many commenters were in favor of the proposed exclusion under
(b)(6) of the proposed rule, now under (b)(7), for artificially
irrigated areas. A few commenters were opposed to the exclusion
entirely, and some commenters were opposed to expanding the exclusion
for other crops and/or aquaculture. Some commenters cited the need for
clarity as to whether the listed crops were the only ones covered under
the exclusion. After considering the comments received, the agencies
have modified this exclusion in the final rule to clarify their intent
that it is not limited to rice and cranberry production and applies
more generally to ``agricultural production.'' The references to
cranberries and rice in the proposed rule were examples and were not an
exhaustive list of crops to which the exclusion would apply. When
evaluating an area to determine whether it meets the exclusion, the
focus should be on whether the area is artificially irrigated or
flooded for the purpose of agricultural production and on whether it
would revert to upland if the irrigation ceases.
 Paragraph (b)(8) of the final rule provides that artificial lakes
and ponds, including water storage reservoirs and farm, irrigation,
stock watering, and log cleaning ponds, are excluded from the
definition of ``waters of the United States'' so long as these features
are constructed or excavated in upland or in non-jurisdictional waters,
and so long as these features are not impoundments of jurisdictional
waters meeting the conditions of paragraph (c)(6). Many commenters
provided edits and additions to the list of water features included in
paragraph (b)(8). However, the agencies did not intend to provide an
exhaustive list of features that are excluded under paragraph (b)(8)
and have determined that any feature that meets the conditions of
paragraph (b)(8) will be non-jurisdictional under this rule.
 The agencies modified the proposed exclusion for artificial lakes
and ponds to clarify their intent. As drafted in the proposed rule, the
exclusion unintentionally would have been narrower than under the 1980s
regulations. For example, when a farm pond is constructed in upland and
connected via a ditch also constructed in upland to divert flow from a
tributary and the farm pond does not connect back into the tributary
system, it has been longstanding agency practice that the farm or stock
pond is non-jurisdictional, similar to irrigation ditches which do not
connect back into the tributary network. The pond's source of water is
the tributary and serves to provide water for irrigation, livestock,
and other agricultural uses. Because such ponds do not contribute
surface water flow to a downstream paragraph (a)(1) water, they have
not been jurisdictional under historic practice and are not
jurisdictional under this final rule. Another example involves a stock
watering pond developed in a non-jurisdictional spring. If that pond
has a spillway that creates a potential surface water connection to a
nearby stream, the pond has traditionally been excluded from CWA
jurisdiction. This final rule adopts that longstanding position.
 In the final rule, the agencies are clarifying that artificial
features including water storage reservoirs and farm, irrigation, stock
watering, and log cleaning ponds are not jurisdictional unless they are
impoundments of jurisdictional waters meeting the conditions of
paragraph (c)(6), as discussed in Section III.F of this notice. The
agencies acknowledge that many artificial lakes and ponds may have been
created by impounding other waters. The text of the final rule
clarifies that artificial lakes and ponds that also meet the conditions
of a jurisdictional impoundment under paragraph (c)(6) are not excluded
under paragraph (b)(8). However, consistent with longstanding practice,
when an applicant receives a permit to impound a water of the United
States in order to construct a waste treatment system (as excluded
under paragraph (b)(12)), under this final rule the agencies are
affirmatively relinquishing jurisdiction over the resulting waste
treatment system as long as it is used for this permitted purpose. Also
consistent with longstanding practice, waters upstream of the waste
treatment system are still considered jurisdictional where they meet
the final rule's definition of ``waters of the United States.''
 The (b)(8) exclusion for artificial lakes and ponds uses the term
``constructed or excavated'' in the final rule, while the proposed rule
used the term ``constructed.'' The agencies do not intend for this
change to alter the meaning of the exclusion from proposal. The
agencies believe that this edit provides clarity to the public about
how excluded artificial lakes and ponds can be created--some are
constructed through dams, dikes, or barriers, while some are excavated
pits. Excavation can entail construction, and construction can entail
excavation, but the agencies have decided to use both terms in the
final rule for added clarity.
 Several commenters stated that artificial lakes and ponds should be
excluded regardless of whether they are located either wholly or
partially in upland, and that the (b)(8) exclusion should extend to
artificial lakes and ponds not constructed or excavated in upland. A
few commenters noted that farmers and ranchers often determine the
location of farm and stock ponds based on topography, which will
typically result in the construction of such features in low areas that
may have some characteristics of wetlands or a natural ephemeral
feature. One commenter noted that many artificial lakes or ponds are
isolated features, and that their connectivity to waters of the United
States rather than their relationship to upland should be the primary
factor in determining jurisdiction.
 The final rule continues to require an artificial lake or pond to
be constructed or excavated wholly in upland or in non-jurisdictional
waters to be considered excluded under (b)(8). This reflects the
agencies' longstanding policy, as discussed above with the stock
watering pond example. Artificial lakes and ponds constructed or
excavated partially in uplands or in non-jurisdictional waters and
partially in jurisdictional waters are jurisdictional if such lakes and
ponds meet the conditions of paragraph (c)(6). The agencies are
concerned that if only
[[Page 22323]]
part of an artificial lake or pond need be in upland, the exclusion
could be inappropriately applied to waters where just a small portion
is constructed in upland. The agencies again note that the mere
interface between the excluded lake or pond otherwise constructed or
excavated wholly in upland and a jurisdictional water does not make
that feature jurisdictional. For example, an artificial lake or pond
that meets the conditions of paragraph (b)(8) and that connects to a
tributary would not be considered jurisdictional. With respect to
artificial lakes and ponds that are constructed in isolated or
ephemeral features, the agencies modified the exclusion to make clear
that artificial lakes or ponds constructed or excavated in non-
jurisdictional features are excluded.
 Paragraph (b)(9) of the final rule excludes water-filled
depressions constructed or excavated in upland or in non-jurisdictional
waters incidental to mining or construction activity, and pits
excavated in upland or in non-jurisdictional waters for the purpose of
obtaining fill, sand, or gravel. In this final rule, the agencies have
modified this exclusion from the proposal. In the proposed rule, such
depressions would have been excluded where they are ``created in
upland,'' but in the final rule such depressions are excluded where
they are ``constructed or excavated in upland or in non-jurisdictional
waters.'' The change from ``created'' to ``constructed or excavated,''
as discussed above, is not meant to change the meaning or applicability
of the exclusion from the proposed rule, but rather is intended to add
clarity to the regulated public about how such excluded water-filled
depressions can be created.
 Aside from this clarifying change, the agencies are finalizing this
exclusion as it was proposed. In the final rule, this exclusion
clarifies longstanding practice reflected in the agencies' 1986 and
1988 preambles, 51 FR 41206, 41217 (November 13, 1986); 53 FR 20764-65
(June 6, 1988) and includes several refinements to the language in
those preambles. In addition to construction activity, the agencies
have also reflected in the final rule an exclusion for water-filled
depressions created in upland incidental to mining activity. This is
consistent with the 1986 and 1988 preambles, which generally excluded
pits excavated for obtaining fill, sand, or gravel, and the agencies
believe there is no need to distinguish between features based on
whether they are created by construction or mining activity.
 Several commenters supported the (b)(9) exclusion, because such
water-filled depressions are often needed for facility management but
are not part of the tributary system and are not natural waters. Some
commenters opposed the exclusion, stating that the exclusion benefited
mining companies and would allow mining activities to negatively impact
water quality. Other commenters stated that the exclusion should be
expanded to include water-filled depressions constructed or excavated
incidental to other activities such as silviculture, or incidental to
all activities, asserting that the agencies should not have singled out
specific industries in the exclusion. With respect to expanding the
exclusion to encompass additional industries or activities, the
agencies note that the (b)(9) exclusion is not the only one that
addresses artificial waters. Paragraph (b) of the final rule excludes a
number of artificial features not limited to specific industries. In
addition, CWA section 404(f) exempts a number of discharges associated
with certain activities in jurisdictional waters from the requirement
to obtain a section 404 permit, including normal farming, ranching, and
silviculture activities as part of an established operation. 33 U.S.C.
1344(f)(1)(A).
 Some commenters wanted the (b)(9) exclusion to be expanded so that
once a water-filled depression was excluded, it remained excluded for
CWA section 404 purposes. The 1986 and 1988 preambles stated that these
depressions were excluded ``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.'' (51 FR 41206, 41217
(November 13, 1986); 53 FR 20764-65 (June 6, 1988)). The agencies
proposed that such water-filled depression would remain excluded, which
represented a change from the 1986 and 1988 preamble language. After
further consideration, and after considering comments received, the
agencies have concluded that once a feature subject to the (b)(9)
exclusion is no longer used for the original purpose for which it was
excluded, it no longer qualifies for the (b)(9) exclusion. This is
consistent with the approach to other exclusions, such as waste
treatment systems and artificially irrigated areas, and reaffirms the
agencies' longstanding practice regarding this exclusion. In many
cases, even if the (b)(9) exclusion may no longer apply to a feature,
the feature may still remain non-jurisdictional because it does not
meet the conditions of paragraphs (a)(1) through (4) and thus is
excluded under paragraph (b)(1).
Stormwater Control Features
 In paragraph (b)(10) of the final rule, the agencies exclude
stormwater control features constructed or excavated in upland or in
non-jurisdictional waters to convey, treat, infiltrate, or store
stormwater runoff. Although stormwater control features are not
specifically included in the list of waters that the agencies consider
to be generally non-jurisdictional per the 1986 and 1988 preamble
language, 51 FR 41206 (November 13, 1986) and 53 FR 20764 (June 6,
1988), the agencies' longstanding practice is to view stormwater
control features that are not built in waters of the United States as
non-jurisdictional. Conversely, the agencies view some relatively
permanent bodies of water, such as channelized streams with
intermittent or perennial flow, as jurisdictional even when used as
part of a stormwater management system. Nothing in this final rule
changes the agencies' longstanding practice. Rather, this exclusion
clarifies the appropriate limits of jurisdiction relating to these
systems.
 A key element of the exclusion is whether the feature or control
system was built wholly in upland or in a non-jurisdictional water. As
discussed above and as further clarified below, the agencies recognize
that upland features may be connected to jurisdictional waters and that
such a connection does not preclude application of the exclusion.
Another key element is that the feature must convey, treat, infiltrate,
or store stormwater. Stormwater control features have evolved
considerably over time, and their nomenclature is not consistent, so in
order to avoid unintentionally limiting the exclusion, the agencies
have not included a list of excluded features in the final rule. The
rule excludes the diverse range of stormwater control features that are
currently in place and may be developed in the future. However, the
agencies note that excluded stormwater control features when they have
channelized surface water may provide a connection between the upstream
reach of a relatively permanent water and a downstream jurisdictional
water such that the upstream reach is jurisdictional. Even in this
circumstance, the stormwater control feature would remain non-
jurisdictional under this final rule. See Section III.D of this notice
for further discussion. The agencies also note that while excluded from
the definition of ``waters of the United States,'' stormwater control
features may function as a conveyance of a discharge of pollutants from
a point source to a water of the United States.
[[Page 22324]]
 Traditionally, stormwater controls were designed to direct runoff
away from people and property as quickly as possible. Cities built
systems to collect, convey, or store stormwater, using structures such
as curbs, gutters, and sewers. Retention and detention stormwater ponds
were built to store excess stormwater until it could be more safely
released. More recently, use of stormwater controls to remove
pollutants before the stormwater is discharged has become more
prevalent. Even more recently, cities have turned to green
infrastructure, using existing natural features or creating new
features that mimic natural hydrological processes that work to
infiltrate, evaporate, or transpire precipitation, to manage stormwater
at its source and keep it out of the conveyance system. These
engineered components of stormwater management systems can address both
flood control and water quality concerns, as well as provide other
benefits to communities. This final rule is designed to avoid
disincentives to this environmentally beneficial trend in stormwater
management practices.
 Many commenters supported the proposed rule's exclusion for
stormwater control features constructed or excavated in upland,
asserting that environmentally beneficial solutions to manage
stormwater could be discouraged if such features were designated as
``waters of the United States.'' Several commenters noted concerns that
an exclusion dependent on an upland location could potentially deter
stormwater system operators from installing beneficial green
infrastructure and suggested that jurisdictional waters incorporated
into the stormwater system should be excluded. Many commenters
suggested that the final rule should define ``stormwater control
features'' that would be excluded.
 The agencies' longstanding practice is to view stormwater control
features as non-jurisdictional when built outside of waters of the
United States. The agencies do not agree with commenters who stated
that jurisdictional waters that are incorporated into a drainage or
stormwater conveyance system should be excluded by virtue of the fact
that they are part of the larger stormwater control system. A water
does not lose its jurisdictional status if it is modified for use as a
stormwater control measure. The agencies recognize that highly
engineered municipal separate storm sewer systems (MS4s) that may have
replaced natural drainage features may therefore have jurisdictional
waters within their systems, but this does not represent a change from
longstanding practice. For example, the Los Angeles River is a
traditional navigable water highly engineered for stormwater control,
and it still meets the requirements of a paragraph (a)(1) water.
Regarding comments related to defining the term ``stormwater control
features,'' the agencies do not name specific stormwater control
features that would fall under the stormwater control feature
exclusion, as they do not want the final rule to be perceived as
limiting the exclusion, particularly given differences among regional
naming conventions and the likelihood that technologies and
nomenclature will evolve in the future.
Groundwater Recharge, Water Reuse, and Wastewater Recycling Structures
 In this final rule under paragraph (b)(11), the agencies exclude
from the definition of ``waters of the United States'' groundwater
recharge, water reuse, and wastewater recycling structures constructed
or excavated in upland or in non-jurisdictional waters. While such
features are not explicitly listed in the categories of waters that the
agencies generally consider to be non-jurisdictional in the 1986 and
1988 preamble language, 51 FR 41206 (November 13, 1986) and 53 FR 20764
(June 6, 1988), this exclusion clarifies the agencies' longstanding
practice that waters and water features used for water reuse and
recycling are not jurisdictional when constructed in upland or in non-
jurisdictional waters. The agencies recognize the importance of water
reuse and recycling, particularly in the arid West where water supplies
can be limited and droughts can exacerbate supply issues. This
exclusion is intended to avoid discouraging or creating barriers to
water reuse and conservation practices and projects. Detention and
retention basins can play an important role in capturing and storing
water prior to beneficial reuse. Similarly, groundwater recharge basins
and infiltration ponds are becoming more prevalent tools for water
reuse and recycling. These features are used to collect and store
water, which then infiltrates into groundwater via permeable soils.
Though these features are often created in upland, they are also often
located in close proximity to tributaries or other larger bodies of
water. The exclusion in paragraph (b)(11) of the final rule codifies
the agencies' longstanding practice and encourages water management
practices that the agencies recognize are important and beneficial.
 Many commenters expressed support for the proposed rule's exclusion
for wastewater recycling structures. Some commenters stated that the
exclusion would encourage water reuse and other innovative approaches
to water management. A few commenters supported the exclusion because
they said wastewater recycling structures should be regulated at the
State level. Some commenters stated that considering a wastewater
recycling structure a water of the United States could create
unnecessary regulatory and economic burdens, while providing no
additional water quality protection. Several commenters stated that the
exclusion of groundwater recharge basins and similar structures was
consistent with Justice Scalia's plurality opinion in Rapanos, as
groundwater recharge basins do not discharge to any navigable waters,
are filled only during part of the year, and do not otherwise
constitute a traditional navigable water within the meaning of the
plurality's jurisdictional test. A number of commenters suggested that
the qualifying language in the proposed rule's wastewater recycling
structures exclusion, which would have limited the exclusion to
wastewater recycling structures ``constructed in upland,'' could create
barriers to water reuse and conservation.
 For the reasons described above, the agencies believe that the
(b)(11) exclusion reflects an appropriate balance among CWA policies
and encouraging water reuse and effective water management. As a
result, this final rule includes the (b)(11) exclusion largely
unchanged from the proposal. The agencies did modify the exclusion in
response to comments to add the term ``water reuse'' to the exclusion
as it is commonly used in water and wastewater management. The agencies
also added ``or non-jurisdictional waters'' to the exclusion to ensure
that it is not narrowly restricted to construction in upland only. As
discussed above, the agencies will apply the qualifier ``constructed or
excavated in upland or in non-jurisdictional waters'' consistently
across four exclusions that use the term.
Waste Treatment Systems
 Paragraph (b)(12) of the final rule excludes waste treatment
systems. The waste treatment system exclusion has existed since 1979
(44 FR 32854), and the agencies are continuing the exclusion under this
final rule. The agencies are also for the first time providing in the
final rule a definition of ``waste treatment system'' under paragraph
(c)(15), so as to clarify which waters and features are considered part
of a waste treatment system and therefore excluded. Continuing the
agencies' longstanding practice, any
[[Page 22325]]
entity with a waste treatment system would need to comply with the CWA
by obtaining a section 404 permit for new construction in a water of
the United States, and a section 402 permit for discharges from the
waste treatment system into waters of the United States. Consistent
with the proposal, the agencies intend for this exclusion to apply only
to waste treatment systems constructed in accordance with the
requirements of the CWA and to all waste treatment systems constructed
prior to the 1972 CWA amendments. One ministerial change in the final
rule from the 2019 Rule is the deletion of a cross-reference to a
regulatory definition of ``cooling ponds'' that no longer exists in the
Code of Federal Regulations.\58\
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 \58\ See 47 FR 52290, 52291, 52305 (Nov. 19, 1982) (deleting
definition of cooling ponds at 40 CFR 423.11(m)).
---------------------------------------------------------------------------
 Many commenters supported the waste treatment system exclusion and
definition as proposed and agreed that the proposed exclusion would
codify the agencies' longstanding practice. Some commenters requested
that the exclusion be expanded to include all ancillary systems,
channels, appurtenances, conveyances, and diversion ditches associated
with the waste treatment system. Other commenters stated that the
proposed exclusion was unlawful and that it should be eliminated
entirely. Some commenters suggested that there may be confusion
concerning the agencies' intent to apply the exclusion to waste
treatment systems constructed prior to the 1972 CWA amendments and
requested that this concept be explicitly included in the final
regulatory text.
 The agencies have considered these public comments and have
finalized the waste treatment exclusion as it was proposed. As noted
above, the agencies agree with commenters that this final rule codifies
the longstanding exclusion that was first included in regulation in
1979. The agencies disagree with suggestions to expand or eliminate the
exclusion and have finalized the definition as proposed. The agencies
also disagree with the suggestion that the exclusion is unlawful and
that there is confusion over the agencies' intent to apply this
exclusion to all waste treatment systems constructed prior to the 1972
CWA amendments. The agencies clearly stated their intent to do so in
the notice of proposed rulemaking and in this final rule, and do not
believe it is necessary to repeat this intent in the regulatory text.
The regulatory text applies to all waste treatment systems that meet
the definition set forth therein, including systems constructed prior
to the 1972 CWA amendments, and there is no basis for construing the
exclusion not to apply to such systems.
 The agencies also considered other exclusions recommended by
stakeholders prior to the proposed rule and suggested in comments on
the proposed rule. The agencies did not include these additional
proposed exclusions in the final rule. Some of the suggested exclusions
were so broadly characterized that they would have introduced confusion
and potentially excluded waters that the agencies have consistently
determined should be covered as waters of the United States. Other
suggested exclusions were so site-specific or activity-based that they
did not warrant inclusion in the nationally-applicable definition.
Still other suggested exclusions were covered by another exclusion in
the rule, and thus would have been superfluous, in whole or in part.
3. How will the agencies implement the final rule?
 To determine whether a water meets the final rule's exclusions in
paragraphs (b)(1) through (b)(12), the agencies will first evaluate
whether the water meets the definition of ``waters of the United
States'' under paragraphs (a)(1) through (4). If the water does not
satisfy any of the paragraph (a)(1) through (4) conditions, it is non-
jurisdictional under paragraph (b)(1). If the water does satisfy one or
more of the conditions to be a paragraph (a)(1) through (4) water, the
agencies will evaluate if the water is identified in any of the
categories of excluded waters and features under paragraphs (b)(2)
through (12) of this final rule. If the water meets any of these
exclusions, the water is excluded even if the water satisfies one or
more of the conditions to be a paragraph (a)(1) through (4) water.
 As discussed above, the agencies' final rule includes an exclusion
for groundwater under paragraph (b)(2), including groundwater drained
through subsurface drainage systems. The final rule clarifies that even
when groundwater is channelized in subsurface systems, like tile drains
used in agriculture, it remains subject to the exclusion. However, the
exclusion does not apply to surface expressions of groundwater, such as
where groundwater discharges to the channel bed and becomes baseflow in
intermittent or perennial streams. The agencies' exclusion for
groundwater in the final rule is consistent with longstanding agency
practice.
 Some commenters requested that the agencies provide guidance as to
how to implement the exclusion for ephemeral features. For example, a
commenter stated that a blanket exclusion of ephemeral streams without
regard to flow quantity could increase the difficulty in delineating
such features and could limit activities to certain time periods. Some
commenters suggested the agencies consider certain ephemeral features
to be jurisdictional on a situational or regional basis, while other
commenters supported a case-by-case determination of ephemeral features
that would fall under the exclusion, rather than excluding ephemeral
features categorically. One commenter requested implementation tools,
including visual aids or benchmarks to identify excluded features,
observing that distinguishing between ephemeral and intermittent waters
may be challenging.
 This final rule is intended to establish categorical bright lines
that provide clarity and predictability for regulators and the
regulated community. Consistent with that goal, the final rule
eliminates the case-specific application of Justice Kennedy's
significant nexus test, and instead establishes clear categories of
jurisdictional waters and non-jurisdictional waters and features that
adhere to the basic principles articulated in the Riverside Bayview,
SWANCC, and Rapanos decisions, including key principles expressed in
Justice Scalia's plurality opinion and Justice Kennedy's concurring
opinion in that case, as discussed at length in this preamble, while
respecting the overall structure and function of the CWA. The agencies
have existing field and remote tools and additional implementation
tools and methods under development that will help distinguish flow
classifications of streams and other waterbodies. The agencies can use
many tools and remote and field-based methods described in Section
III.D.3 to distinguish between paragraph (b)(3) ephemeral streams,
swales, gullies, rills, and pools and paragraph (b)(4) areas with
diffuse stormwater run-off and directional sheet flow over upland,
while comparing both against waters subject to jurisdiction under
paragraph (a). Under past and existing practice, the agencies have
substantial experience using remote tools and field observations to
distinguish between channelized and non-channelized features, and the
agencies expect that many landowners can distinguish between these
features using visual observations. Under this final rule, landscapes
with non-channelized, diffuse stormwater and overland sheet flow are
excluded regardless of the flow regime characteristics, because under
[[Page 22326]]
these circumstances, flow is occurring only in direct response to
precipitation over areas that meet the definition of ``upland.'' As
explained by the Rapanos plurality, regulating these features as waters
of the United States extends beyond the rational meaning of the term.
547 U.S. at 734.
 With respect to implementing the final rule's paragraph (b)(5)
exclusion for certain ditches, the reach of a ditch that meets
paragraph (a)(1) or (2) of the final rule is considered a water of the
United States, with ``reach'' interpreted similarly to how it is used
for tributaries in Section III.D of this notice (i.e., a section of a
ditch along which similar hydrologic conditions exist, such as
discharge, depth, area, and slope). The jurisdictional status of other
reaches of the same ditch must be assessed based on the specific facts
and under the terms of the final rule to determine the jurisdictional
status of those reaches. For example, a ditch that is constructed in a
tributary is not an excluded ditch under paragraph (b)(5) so long as it
satisfies the flow conditions of the ``tributary'' definition or the
conditions of the ``adjacent wetlands'' definition as further described
in Section III.D and Section III.E. Further, the ditch exclusion does
not affect the possible status of a ditch as a point source. Also, a
ditch constructed in an adjacent wetland that satisfies the conditions
of paragraph (a)(4) is not excluded. The agencies believe that the
final rule's ditch exclusion encompasses most irrigation and drainage
ditches, including most roadside and other transportation ditches, as
well as most agricultural ditches.
 In paragraph (b)(6) of this final rule, the agencies are
reconfirming the longstanding prior converted cropland exclusion. This
final rule also codifies the abandonment principle as applied to the
prior converted cropland exclusion, as first articulated in the 1993
preamble (58 FR 45033), and provides additional clarification regarding
what constitutes ``agricultural purposes.'' As a result of this final
rule, the change in use analysis will no longer be used to evaluate
whether the prior converted cropland exclusion applies. Under the final
rule, when cropland has been abandoned (i.e., the cropland has not been
used for or in support of agricultural purposes for a period of greater
than five years), and wetlands have returned, any prior converted
cropland designation for that site will no longer be valid for purposes
of the CWA.
 The USDA is responsible for making determinations as to whether
land is prior converted cropland for its FSA purposes, whereas the
agencies are responsible for determining applicability of the exclusion
for CWA purposes, consistent with the government's longstanding
interpretation of the agencies' authority under the CWA. See 33 CFR
328.3(a)(8) (``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.''); CWA Regulatory Programs, 58 FR
45,008, 45,036 (Aug. 25, 1993); Administrative Authority to Construe
Sec. 404 of the Federal Water Pollution Control Act (``Civiletti
Memorandum''), 43 Op. Att'y Gen. 197 (1979). The agencies will defer to
USDA for purposes of establishing whether a parcel or tract of land has
received a prior converted cropland determination and is therefore
eligible for the prior converted cropland exclusion under this rule. A
landowner without an existing prior converted cropland determination
may seek a new determination from the USDA.\59\ The USDA is subject to
specific statutes designed to protect landowner privacy and, as such,
is prohibited from making certain parcel-specific information available
without the landowner's consent. To ensure that the agencies can rely
on a USDA prior converted cropland determination, the landowner will
need to either provide a copy of the determination or provide the
agencies with a signed consent form to allow the agencies access to the
relevant information for the limited purpose of verifying USDA's prior
converted cropland determination. The agencies recognize that privacy
and confidentiality issues concerning certain producer information is
addressed at section 1619 of the Food, Conservation, and Energy Act of
2008 (7 U.S.C. 8791(b)) and section 1244(b) of the Food Security Act of
1985, as amended (16 U.S.C. 3844(b)). If a parcel is found to be prior
converted cropland, as defined in this rule, it is not a water of the
United States.
---------------------------------------------------------------------------
 \59\ The agencies note that the USDA's regulatory definition of
``prior converted cropland'' in the FSA and the definition being
established in this final rule have different purposes and they are
substantively different. Based on the FSA's statutory requirements,
the USDA definition of ``prior converted cropland'' requires that
agricultural commodity crop production be made possible prior to
1985. See 7 CFR 12.2(a)(8); 16 U.S.C. 3801 (defining converted
wetland) and 16 U.S.C. 3822(b)(1)(A) (establishing the pre-1985
exemption). If commodity crop production was made possible on a
particular parcel or tract of land prior to 1985, that land is
eligible for the prior converted cropland exclusion in this final
rule. Once eligibility is determined, the agencies will evaluate the
land to determine if the exclusion currently applies, or if the land
has been abandoned, as described in this final rule.
---------------------------------------------------------------------------
 Once a threshold determination has been made that certain lands are
prior converted cropland, the EPA and the Corps are responsible for
implementing the prior converted cropland exclusion for CWA purposes
and identifying (as further explained below) whether the lands have
been abandoned and whether wetlands conditions have returned such that
they are no longer eligible for the prior converted cropland exclusion
in this rule and thus may be waters of the United States. In addition
to working closely with the USDA, the agencies will consider
documentation from NOAA and FEMA when evaluating whether a parcel of
land may no longer be eligible for the CWA prior converted cropland
exclusion. In all cases, the burden to prove that such parcel is a
water of the United States remains on the agencies. The agencies'
implementation of the prior converted cropland exclusion for CWA
regulatory purposes does not affect the USDA's administration of the
FSA or a landowner's eligibility for benefits under FSA programs.\60\
---------------------------------------------------------------------------
 \60\ See the Notice of Proposed Rulemaking at 84 FR 4193 for a
summary of how the agencies historically implemented and enforced
this exclusion.
---------------------------------------------------------------------------
 Under the final rule, to determine the continuing applicability of
the prior converted cropland exclusion, the Corps must first determine
whether the land has been ``abandoned.'' As described previously, prior
converted cropland will be considered abandoned if it is not used for,
or in support of, agricultural purposes at least once in the
immediately preceding five years. In making an abandonment
determination, the Corps will work with the landowner and USDA, as
appropriate, to determine whether the land is currently or has been
used for or in support of agricultural purposes at least once in the
immediately preceding five years. As noted above, there are many uses
that may fall within this category, including but not limited to,
grazing; haying; idling land for conservation purposes (e.g., habitat;
pollinator and wildlife management; and water storage, water 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. Some of those
land uses may not be obvious to Corps field staff, so the agencies may
rely on public or private documentation to demonstrate that the land is
enrolled in a conservation program or is otherwise
[[Page 22327]]
being used for or in support of agricultural purposes. Such information
may include aerial photographs, topographical maps, cultivation maps,
crop expense or receipt records, field- or tract-specific grain
elevator records, and other records generated and maintained in the
normal course of doing business, including government agency records
documenting participation in a conservation program, and other
documentation reasonably establishing one or more ``agricultural
purposes.''
 The final rule requires that the land be used for or in support of
agricultural purposes within the immediately preceding five years. In
implementing this requirement, the agencies will consider documentation
from USDA, NOAA, FEMA, and other Federal and State agencies to
determine whether the land was used for or in support of agricultural
purposes in the immediately preceding five years. For example, USDA
administers multiple programs that track whether fields have been
planted or harvested in the normal course, or enrolled in long-term
conservation rotations, and the agency provides crop insurance for
years where those activities were halted for reasons covered under
their insurance policies; NOAA tracks long- and short-term weather
patterns and can provide information and data concerning flood or
drought conditions that may cause or contribute to idling land in
support of agricultural purposes; and FEMA administers emergency
response programs for natural disasters, including hurricanes,
wildfires, and other events that could also require idling land for
soil recovery and other agricultural purposes. The agencies will take
into account this information, and additional documentation reasonably
establishing ``agricultural purposes'' when evaluating whether cropland
has been used for or in support of agricultural purposes in the
immediately preceding five years.
 If the Corps determines that the land is abandoned, then it must
evaluate the current condition of the land to determine whether wetland
conditions have returned. If wetlands are currently present on the
property, the agencies will determine whether the wetlands are
``adjacent wetlands'' and therefore ``waters of the United States,''
consistent with this final rule. As the term ``prior converted
cropland'' suggests, and as stated in the preamble to the 1993 Rule,
land properly designated as prior converted cropland has typically been
so extensively modified from its prior condition that it no longer
exhibits wetland hydrology or vegetation, and no longer performs the
functions it did in its natural and original condition as a wetland. 58
FR 45032. It is often altered and degraded, with long-term physical and
hydrological modifications that substantially reduce the likelihood of
reestablishment of hydrophytic vegetation. Consistent with longstanding
agency policy and wetland delineation procedures, if a former wetland
has been lawfully manipulated to the extent that it no longer exhibits
wetland characteristics under normal circumstances, it would not be
jurisdictional under the CWA. The altered nature of prior converted
cropland and its conditions constitute the ``normal circumstances'' of
such areas. The agencies expect the majority of prior converted
cropland in the nation to fall into this category and not to be subject
to CWA regulation, even after it is abandoned. However, at least some
abandoned prior converted cropland may, under normal circumstances,
meet the definition of ``wetlands'' under paragraph (c)(16).
 In paragraph (b)(7), the agencies clarify their longstanding view
that the artificial irrigation exclusion applies only to the specific
land being artificially irrigated, including fields flooded for
agricultural production, including but not limited to rice or cranberry
growing, which would revert to upland should artificial irrigation
cease. Historically, the agencies have taken the position that ponds
for rice growing are generally not considered waters of the United
States, as reflected in the 1986 and 1988 preambles. See 51 FR 41206,
41217 (November 13, 1986) and 53 FR 20764-65 (June 6, 1988). In the
past, the agencies have considered those under the artificial lakes or
ponds category of waters that are generally non-jurisdictional, but
this final rule includes them in the artificial irrigation exclusion
category as any wetland crop species, such as rice and cranberry
operations, that is typically supplied with artificial flow irrigation
or similar mechanisms.
 A number of commenters addressed the difficulty in proving that
land would revert to upland when irrigation ceased and suggested
clarification as to whether documentation was needed as proof. The
agencies agree that proving that land would revert to upland may be
challenging in some circumstances. The agencies have developed
strategies and guidance to assist with determining if wetland
conditions will persist when irrigation ceases. This includes, but is
not limited to, utilizing aerial photography, soil maps, LiDAR, remote
sensing, and field assessments to determine if wetland conditions are
the result of irrigation or are naturally occurring.
 Commenters also raised concern about whether the exclusion is only
available for rice and cranberry growing areas. The inclusion of rice
and cranberries in the proposed rule were simply examples and not
intended to be exhaustive. In this final rule, the agencies conclude
that it is not necessary to list all crops potentially eligible for the
exclusion, and therefore simply reference ``agricultural production.''
The relevant factor in determining the application of the exclusion is
not what type of crop may be planted or cultivated, but whether the
area is artificially irrigated and would revert to upland should
irrigation cease.
 Under the final rule, the exclusion for waters meeting the
conditions of paragraph (b)(8) applies to artificial lakes and ponds
created through construction or excavation in upland or in non-
jurisdictional features. Such artificial lakes and ponds would not be
jurisdictional under the final rule even if they maintain a hydrologic
surface connection to waters of the United States or are inundated by
waters of the United States. Conveyances created in upland that are
physically connected to and are a part of the excluded feature also are
excluded.
 A commenter inquired as to whether the artificial waterbody created
by impounding a jurisdictional tributary would be jurisdictional. The
agencies note that under the final rule, impoundments are considered
jurisdictional if they impound a paragraph (a)(1) through (4) water,
which includes jurisdictional tributaries, and contribute surface water
flow in a typical year to a paragraph (a)(1) water or are inundated by
flooding from a paragraph (a)(1) through (3) water in a typical year.
Impounding a jurisdictional tributary does not create a non-
jurisdictional lake or pond that would be excluded under paragraph
(b)(8), but rather creates a jurisdictional impoundment so long as it
meets the conditions of paragraph (a)(3) as defined in paragraph
(c)(6). The agencies note that artificial lakes and ponds that are
excluded from the definition of ``waters of the United States'' could,
in some circumstances, be point sources of pollutants subject to
sections 301 and 402 of the Act.
 Under paragraph (b)(9), water-filled depressions constructed or
excavated in upland or in non-jurisdictional waters that are incidental
to mining or construction activity, and pits excavated in upland or in
non-jurisdictional waters for the purpose of obtaining fill,
[[Page 22328]]
sand, or gravel are excluded from the definition of ``waters of the
United States.'' To determine whether a water or feature meets this
exclusion, the agencies will evaluate whether the water feature is
constructed or excavated in upland or in non-jurisdictional waters as
part of these industrial activities. In addition, such water-filled
depressions and pits could become waters of the United States once
construction or mining activities have permanently ceased and the
depressions or pits meet the conditions of a paragraph (a)(1) through
(4) water.
 The final rule excludes in paragraph (b)(10) stormwater control
features constructed or excavated in upland or in non-jurisdictional
waters to convey, treat, infiltrate, or store stormwater run-off. As
stated previously, the rule excludes a diverse range of stormwater
control features that are currently in place and that may be developed
in the future. To determine if such a water or feature meets the
exclusion, the agencies will evaluate whether the stormwater feature is
constructed or excavated in upland or in non-jurisdictional waters.
 Paragraph (b)(11) of the final rule clarifies that groundwater
recharge, water reuse, and wastewater recycling structures constructed
or excavated in upland or in non-jurisdictional waters are excluded. To
determine whether a such a structure meets this exclusion, the agencies
will evaluate whether the water or feature is constructed or excavated
in upland or in non-jurisdictional waters. This exclusion includes
detention and retention basins as well as groundwater recharge basins
and infiltration ponds excavated in upland or in non-jurisdictional
waters for wastewater recycling. The exclusion also covers water
distributary structures that are built in upland or in non-
jurisdictional waters for water recycling. These features often connect
or carry surface water flow to other water recycling structures, for
example, a channel or ditch that carries water to an infiltration pond.
Consistent with longstanding practice, the agencies do not consider
these water distributary systems jurisdictional.
 As discussed previously, the agencies are not changing the
longstanding approach to implementing the waste treatment system
exclusion. As a result, the agencies will continue to apply the
exclusion to systems that are treating water to meet the requirements
of the CWA. Discharges from these systems to waters of the United
States would continue to be subject to regulation by the CWA section
402 permitting program. Similarly, if a waste treatment system is
abandoned or otherwise ceases to serve the treatment function for which
it was designed, it does not continue to qualify for the exclusion.
 Some commenters suggested the agencies clarify the way in which the
waste treatment system exclusion is currently implemented. Many
comments inquired as to whether stormwater systems and wastewater reuse
facilities are considered part of a complete waste treatment system for
purposes of the waste treatment system exclusion. To enhance clarity,
the agencies have provided in the final rule two related exclusions in
paragraphs (b)(10) and (b)(11) and have added settling basins and
cooling ponds to the definition of ``waste treatment system'' in
paragraph (c)(15). The agencies note that cooling ponds that are
created under CWA section 404 in jurisdictional waters and that have
CWA section 402 permits are subject to the waste treatment system
exclusion under the 2019 Rule and will also be excluded under the final
rule. Cooling ponds created to serve as part of a cooling water system
with a valid State or Federal permit constructed in waters of the
United States prior to enactment of the 1972 amendments of the CWA and
excluded from jurisdiction under the 2019 Rule also remain excluded
under the final rule. Some commenters on the proposed rule's waste
treatment system exclusion expressed confusion regarding whether
stormwater treatment features would be excluded under the exclusion for
stormwater control features or under the waste treatment exclusion.
Such determinations will depend on the specific attributes of the
control and the water feature and thus need to be made on a case-by-
case basis. It is possible that a stormwater feature could qualify for
both the stormwater control features exclusion and the waste treatment
systems exclusion. This same principle applies to other exclusions that
may have similar cross-over features, like certain ditches used in
stormwater management systems.
 It is important to reiterate that while the waters and features
listed in the final rule's exclusions are not waters of the United
States, some of them may convey surface water flow to a downstream
jurisdictional water, so that reaches of a water upstream and
downstream of the excluded water or feature may meet the definition of
``tributary'' in paragraph (c)(12). For example, when some water from a
tributary is moved into a downstream jurisdictional water through an
excluded ditch, the ditch itself is excluded from jurisdiction under
the final rule but the tributary upstream of the ditch is
jurisdictional if the non-jurisdictional ditch conveys surface water
flow in a typical year to the downstream jurisdictional reach.
I. Placement of the Definition of ``Waters of the United States'' in
the Code of Federal Regulations
1. What are the agencies finalizing?
 The definition of ``waters of the United States'' has historically
been placed in eleven locations in the Code of Federal Regulations
(CFR). For the sake of simplicity, in this final rule, the agencies are
codifying the definition of ``waters of the United States'' in only two
places in the CFR--once in Title 33 (which implements the Corps'
statutory authority) and once in Title 40 (which generally implements
the EPA's statutory authority).
2. Summary of Final Rule Rationale and Public Comment
 The agencies proposed to maintain the definition of ``waters of the
United States'' at 33 CFR 328 and in ten locations in Title 40. The
agencies solicited comment on an alternative approach under which the
definition would be codified in just two locations within the CFR,
rather than in the eleven locations in which it has previously
appeared. Most commenters recommended that the definition of ``waters
of the United States'' be codified twice, once in Title 33 of the CFR
and once in Title 40 of the CFR. These commenters recommended limiting
codification to two locations in order to clarify that there is a
single definition of ``waters of the United States'' applicable to the
entire CWA, to reduce confusion and conflicting interpretations under
different programs, and to promote ease of use for the regulated
community and for laypersons. Many of these commenters suggested
including a cross-reference in the original ten locations of Title 40
of the CFR. Some commenters recommended continuing the agencies'
practice of codifying the definition of ``waters of the United States''
in eleven locations within the CFR.
 The agencies agree with commenters that stated that codifying the
definition of ``waters of the United States'' in two locations within
the CFR will reduce confusion and promote ease of use for States,
Tribes, local government, the regulated community, and the general
public. With this final rule, the agencies are codifying the definition
of ``waters of the United States'' in Title 33 of the CFR, which
implements the Corps' statutory authority, at 33 CFR 328.3, and in
Title 40, which generally implements
[[Page 22329]]
the EPA's statutory authority, at 40 CFR 120.2. In the sections of the
CFR where the EPA's regulatory 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, this final rule cross-references the
newly created section of the regulations containing the definition of
``waters of the United States.'' The agencies have placed the EPA's
definition of ``waters of the United States'' in a previously
unassigned part of 40 CFR. The change in placement has no implications
on CWA program implementation; it is made for the sole purpose of
enhancing the clarity of the federal regulations. Placing the
definition of ``waters of the United States'' in a single section in
the part of the regulations that implements the EPA's authority and
once again in the part of the regulations that implements the Corps'
authority makes clearer to members of the public that there is a single
definition of ``waters of the United States'' applicable to the CWA and
its implementing regulations.
IV. State, Tribal, and Federal Agency Datasets of Waters of the United
States
 During the extensive pre-proposal outreach to the general public
and focused engagement with States and Tribes, the agencies heard from
a number of States about their familiarity with waters within their
borders and their expertise in aquatic resource mapping. As co-
implementers of CWA programs, they also emphasized the potential
benefit of greater State and tribal involvement in jurisdictional
determinations. For these reasons, several States suggested that the
agencies consider their knowledge and increase the role of States and
Tribes in identifying those waters that are waters of the United
States. Stakeholders also indicated that maps could increase certainty
and transparency regarding the data and methods used to determine which
waters are jurisdictional and which waters are not.
 In the Notice of Proposed Rulemaking for this rule, the agencies
solicited comment as to how to create a regulatory framework that would
authorize interested States, Tribes, and other Federal agencies to
develop for the agencies' approval geospatial datasets representing
waters of the United States, as well as waters excluded from the
definition, ``waters of the State'' or ``waters of the Tribe'' within
their respective borders. 84 FR 4154, 4198-4200 (February 14, 2019).
This concept was not part of the proposed regulatory text; the agencies
utilized the notice to solicit input and suggestions from the regulated
public, States, Tribes, and other stakeholders.
 Some commenters raised concerns regarding the limitations of data
currently available for creating geospatial datasets of jurisdictional
waters, particularly commenting on the limitations of national datasets
such as the National Hydrography Dataset (NHD) and the National
Wetlands Inventory (NWI). Some commenters expressed concerns about the
resolution, completeness, accuracy, and usefulness of publicly-
available data, with some stating that geospatial datasets cannot
accurately assess the details needed to remotely determine or delineate
jurisdictional waters. Other commenters noted that, despite the
limitations in the available data, the agencies should attempt to
quantify changes in the jurisdictional status of specific waterbody
categories as a result of the final rule.
 The agencies agree that there are significant limitations to the
extent to which currently available data can be used to identify the
scope of all or even a subset of jurisdictional waters. There are
currently no comprehensive datasets through which the agencies can
depict the universe of federally-regulated waters under the CWA. For
example, the agencies attempted to use the NHD at high resolution and
NWI to assess the potential change in CWA jurisdiction as a result of
the proposed rule to revise the definition of ``waters of the United
States,'' but ultimately concluded that the limitations of these
datasets precluded their use for quantifying the extent of waters whose
jurisdictional status could change under the proposed rule, as
discussed in Section V and in the Resource and Programmatic Assessment
for the final rule. Due to these limitations, which were confirmed
during the public comment period for the proposed rule and an
evaluation by the agencies, the agencies also did not use the NHD or
NWI to assess potential changes in jurisdiction as a result of the
final rule.
 While the NHD and NWI are the most comprehensive hydrogeographic
datasets mapping waters and wetlands in the United States and are
useful resources for a variety of Federal programs, including CWA
programs, they currently have technical limitations that present
significant challenges for use as standalone tools to determine the
full scope of CWA jurisdiction and for creating geospatial datasets of
jurisdictional waters, regardless of the regulatory definition of
``waters of the United States.'' Importantly, the NHD and NWI were not
created for regulatory purposes, so their limitations as comparative
tools for CWA jurisdiction are not surprising.
 Due in part to the resolution of the data, limitations of the NHD
for purposes of accurately mapping the scope of jurisdictional waters
under the CWA include errors of omission (e.g., failure to map streams
that exist on the ground); errors of commission (e.g., mapping streams
that do not exist on the ground); horizontal positional inaccuracies;
misclassification of stream flow condition, particularly in headwaters;
and inconsistent mapping in different parts of the country. The NWI
presents similar challenges for identifying federally-regulated waters,
including the foundational obstacle of having a ``wetlands'' definition
that differs from the federal regulatory ``wetlands'' definition. The
NWI also contains errors of omission (e.g., failure to map wetlands
that exist on the ground), errors of commission (e.g., mapping wetlands
that do not exist on the ground), and potentially inaccurate wetland
boundary identification. The limitations identified herein are examples
and do not represent an exhaustive list of challenges faced by the
agencies in potentially using them to identify the scope of CWA
jurisdiction. For a more detailed discussion of the NHD and NWI
datasets and their limitations for use as standalone tools to determine
the full scope of waters that are and are not waters of the United
States, see Chapter II of the Resource and Programmatic Assessment
supporting this final rule.
 It has been the consistent position of the agencies that the NHD
and the NWI do not represent the scope of waters subject to CWA
jurisdiction.\61\ Indeed,
[[Page 22330]]
as part of the 2015 rulemaking, the agencies stated that they ``do not
have maps depicting waters of the United States under either present
regulatory standards or those in the final [2015] rule.'' \62\ This
remains true today; the agencies do not have maps of waters of the
United States under the 2015 Rule, under the 2019 Rule, or under this
final rule. For this reason, and to provide the public and the agencies
with more information on which waters are or are not waters of the
United States, the agencies sought public comment on a possible
framework for developing geospatial datasets.
---------------------------------------------------------------------------
 \61\ See, e.g., Letter from Nancy Stoner, Acting Assistant
Adm'r, EPA Office of Water, to Lamar Smith, Chairman, Comm. on
Science, Space, and Tech., U.S. House of Representatives (July 28,
2014) (emphasis added), available at https://web.archive.org/web/20180919173837/https://science.house.gov/sites/republicans.science.house.gov/files/documents/epa_releases_maps_letter.pdf. (``[N]o national or statewide maps
have been prepared by any agency, including EPA, showing the scope
of waters subject to the Clean Water Act. . . . To develop maps of
jurisdictional waters requires site-specific knowledge of the
physical features of water bodies, and these data are not
available[.]'') (emphasis added); see also Letter from Nancy Stoner,
Deputy Assistant Adm'r, EPA Office of Water, to Lamar Smith,
Chairman, Comm. on Science, Space, and Tech., U.S. House of
Representatives (August 6, 2014), available at https://web.archive.org/web/20180919173837/https://science.house.gov/sites/republicans.science.house.gov/files/documents/epa_releases_maps_letter.pdf); U.S. EPA, Mapping the Truth, The EPA
Blog (Aug. 28, 2014), available at https://blog.epa.gov/2014/08/28/mapping-the-truth/ (``While these [U.S. Geological Survey and Fish &
Wildlife Service] maps are useful tools for water resource managers,
they cannot be used to determine Clean Water Act jurisdiction--now
or ever.''); Letter from Kenneth J. Kopocis, Deputy Assistant Adm'r,
EPA Office of Water, to Lamar Smith, Chairman, Comm. on Science,
Space, and Tech., U.S. House of Representatives (Jan. 8, 2015)
(``These [USGS] maps were not prepared for the purpose of, nor do
they represent, a depiction of the scope of waters protected under
the Clean Water Act.''); Impact of the Proposed ``Waters of the
United States''' Rule on State and Local Governments Before the H.
Comm. on Transp. & Infrastructure and the S. Comm. on Env't & Pub.
Works, 114th Cong. (2015)(testimony of Gina McCarthy, Adm'r,
EPA)(stating that the NHD and NWI maps were ``not used to determine
jurisdiction and not intended to be used for jurisdiction,'' ``are
not relevant to the jurisdiction of the `waters of the U.S.',''
``are not consistent with how we look at the jurisdiction of the
Clean Water Act,'' and have ``nothing to do, as far as I know, with
any decision concerning jurisdiction of the Clean Water Act'').
 \62\ See Response to Comments for the Clean Water Rule, Clean
Water Rule Comment Compendium Topic 8: Tributaries, Docket ID. No.
EPA-HQ-OW-2011-0880-20872, p. 442, https://www.regulations.gov/document?D=EPA-HQ-OW-2011-0880-20872.
---------------------------------------------------------------------------
 The agencies acknowledge that they have previously taken the
position that ``maps of all the jurisdictional or non-jurisdictional
waters are not feasible,'' \63\ and that maps ``cannot be used to
determine Clean Water Act jurisdiction--now or ever,'' see U.S. EPA,
Mapping the Truth, The EPA Blog (August 28, 2014). Rather than
declaring the task too difficult, the agencies have decided to initiate
development of state-of-the-art geospatial data tools through Federal,
State, and tribal partnerships to provide an enhanced, publicly-
accessible platform for critical CWA information, such as the location
of federally jurisdictional waters, the applicability of State and
tribal water quality standards, permitted facility locations, impaired
waters, and other significant features. Such mapped features would make
it easier for agency field staff, the general public, property owners,
permit-holders and others to understand the relationship between
familiar geographical features and the overlay of CWA jurisdictional
waters. For Federal, State, and tribal agencies, such geospatial
datasets could improve the administration of CWA programs and
attainment of water quality goals. Geospatial datasets and resulting
future maps that indicate waters likely subject to federal jurisdiction
could allow members of the regulated community to more easily and
quickly ascertain whether they may want to contact a government agency
regarding the potential need for a CWA permit. These datasets, when
fully developed, would promote greater regulatory certainty, relieve
some of the regulatory burden associated with determining the need for
a permit, and play an important part in helping to attain the goals of
the CWA. In the future, the agencies and States could use geospatial
datasets to identify waters with applicable water quality standards,
total maximum daily loads, water quality monitoring data, and other
beneficial information in one layered geospatial map.
---------------------------------------------------------------------------
 \63\ Id. at p. 593.
---------------------------------------------------------------------------
 Since the proposed rule was published, the agencies have been
engaging with other Federal agencies to discuss existing geospatial
datasets and discuss opportunities to build upon them to map the
nation's aquatic resources, including both waters of the United States
and non-jurisdictional waters. To align the agencies' waters of the
United States mapping interests with the U.S. Department of Interior's
(DOI) established and ever-improving aquatic resource mapping efforts,
including the NHD, NWI, and other datasets, the EPA and the Corps are
engaging with the U.S. Geological Survey (USGS) and the U.S. Fish and
Wildlife Service (FWS) and have established a technical working group
to develop strategies that can address their CWA mapping needs.\64\ The
agencies believe the most efficient way to address their regulatory
needs is to better align their efforts with DOI's existing processes
and national mapping capabilities. The EPA, USGS, and FWS have a long
history of working together to map the nation's aquatic resources. As
the agencies pursue this mapping effort, they will continue to
collaborate with DOI to enhance the NHD, NWI, and other products to
better map the nation's water resources and the waters of the United
States while enhancing their utility to other CWA programs that the EPA
and the Corps implement.
---------------------------------------------------------------------------
 \64\ See Letter from David Ross, Asst. Adm'r, EPA Office of
Water, and Ryan Fisher, Principal Deputy Asst. Sec. of the Army
(Civil Works), U.S. Army, to Dr. Tim Petty, Asst. Sec. for Water and
Science, U.S. DOI, and Rob Wallace, Asst. Sec. for Fish, Wildlife,
and Parks, U.S. DOI (September 17, 2019); see also Letter from Dr.
Jim Reilly, Director, U.S. Geological Survey, to David Ross, Asst.
Adm'r, EPA Office of Water, and Ryan Fisher, Principal Deputy Asst.
Sec. of the Army (Civil Works), U.S. Army (October 1, 2019); see
also Letter from Gary Frazer, Asst. Dir. for Ecological Services,
U.S. Fish and Wildlife Service to David Ross, Asst. Adm'r, EPA
Office of Water, and Ryan Fisher, Principal Deputy Asst. Sec. of the
Army (Civil Works), U.S. Army (December 4, 2019).
---------------------------------------------------------------------------
 In addition, the EPA's Office of Research and Development (ORD) has
established an ``Improved Aquatic Resource Mapping'' research area,
which will be implemented in coordination with the Corps and EPA's
Office of Water. This research area could build upon longstanding EPA
aquatic resource research and leverage existing research partnerships
with other Federal agencies, States, and Tribes to improve mapping of
aquatic resources. This research effort is intended to support the
agencies' need for improved data to inform CWA jurisdictional
determinations, to support other regulatory and non-regulatory needs,
and to contribute to ongoing and new EPA research. In the long-term,
the agencies anticipate that this effort will yield improved methods of
verifying aquatic resources to support CWA jurisdictional
determinations and other programmatic needs. In the short-term, ORD
intends to produce three primary products to begin to advance this
goal: A review of the existing aquatic resource mapping methodologies,
development of novel geospatial datasets in select watersheds, and
development of calibration and validation datasets. All three products
can incorporate outreach efforts to communicate and transfer results to
stakeholders.
 The agencies also believe that any future efforts they pursue to
work with States, Tribes, and Federal agencies to create geospatial
datasets of jurisdictional waters will improve the data and information
that is available to the public about the jurisdictional scope of the
CWA, recognizing that data limitations may always exist. Many
commenters supported the development of geospatial datasets or a
mapping system of waters of the United States to provide a clear
understanding of the presence or absence of jurisdictional waters. Many
such commenters provided caveats and anticipated challenges. Other
commenters suggested that creating such datasets posed too many
challenges to be worthwhile. Many of these commenters considered the
development of geospatial datasets of jurisdictional waters to be
infeasible or inappropriate based on the need for field verification
and maintenance to keep the datasets up-to-date, and the concern that
potentially incomplete lists could be inaccurately perceived as a
definitive list of all waters of the United States. These commenters
stated that any datasets established should be used
[[Page 22331]]
only as a planning tool to inform jurisdictional determinations or to
provide guidance on the location of potential waters of the United
States.
 The agencies solicited comment on potential approaches to
establishing a framework to allow States, Tribes, or Federal agencies
to create geospatial datasets of jurisdictional waters. Some commenters
supported deferring this effort to a future rulemaking. Several
commenters recommended using existing technology to prioritize mapping
traditional navigable waters prior to attempting to map jurisdictional
tributaries or wetlands. A few commenters suggested engaging in several
pilot projects or a phased approach before rolling out a dataset
nationwide. Some commenters suggested that data in the geospatial
datasets should either expire or be updated every five years, to
reflect the timeframe for approved jurisdictional determinations or to
ensure that the datasets effectively represent current conditions.
 The agencies solicited comment on appropriate features and
attributes of the website that would publish this information, as well
as any privacy considerations the agencies should understand. A few
commenters opposed making public the details of jurisdictional
determinations or expressed privacy concerns regarding the creation of
geospatial datasets of jurisdictional waters. Some commenters stated
that jurisdictional determinations or geospatial datasets of
jurisdictional waters should be made available to the public.
 As the agencies work to pursue improved geospatial mapping of
waters in the future, they intend to also work to enhance information
that is already available to the public on jurisdictional
determinations. The Corps maintains a website at https://permits.ops.usace.army.mil/orm-public that presents information on the
Corps' approved jurisdictional determinations and CWA section 404
permit decisions. Similarly, the EPA maintains a website at https://watersgeo.epa.gov/cwa/CWA-JDs/ that presents information on approved
jurisdictional determinations made by the Corps and the EPA under the
CWA since August 28, 2015. These websites will incorporate approved
jurisdictional determinations made under the revised definition of
``waters of the United States'' that the agencies are finalizing in
this notice.
 In the Notice of Proposed Rulemaking, the agencies expressed
interest in learning about experiences States, Tribes, and other
Federal agencies have had with mapping aquatic resources and using this
information for program implementation. A few State and tribal
commenters expressed interest in working as partners with the agencies
on mapping jurisdictional waters. Some State and local governments
offered to share existing geospatial data with the agencies. Other
State commenters were less supportive of an effort to map
jurisdictional waters, with some raising concerns about the regulatory
implications of mapping based on experiences in their States. Several
State commenters raised concerns about costs of a mapping effort, with
some commenters pointing to their own costly past mapping efforts. One
commenter cited a State study that found that the State's best attempt
at mapping wetlands was only 56 percent successful at classifying
wetlands compared to field delineations. The agencies will consider the
comments and concerns raised and coordinate closely with States,
Tribes, and other Federal agencies in future efforts to develop
geospatial datasets. The agencies do not anticipate developing a
regulatory framework for geospatial datasets that would impose
requirements on States and Tribes to develop geospatial datasets of
jurisdictional waters; the option would simply be available for
interested States and Tribes.
 The agencies believe that pursuing the development of geospatial
datasets of waters of the United States could provide for greater
regulatory certainty and provide important information to States,
Tribes, the regulated community, and the public. The agencies are in
the early stages of this effort, and they will be informed by public
comments and suggestions received in response to this rulemaking as
they move forward.
V. Overview of the Effects of the Rule and Supporting Analyses
 This section provides an overview of the potential effects of the
final rule on federal and state regulatory programs and potential
economic impacts of the final rule. Additional detail on these analyses
are contained in and described more fully in the Resource and
Programmatic Assessment for the Navigable Waters Protection Rule:
Definition of ``Waters of the United States'' and in the Economic
Analysis for the Navigable Waters Protection Rule: Definition of
``Waters of the United States.'' Copies of these documents are
available in the docket for this action.
 In defining the term ``waters of the United States'' under the CWA,
Congress gave the agencies discretion to articulate reasonable limits
on the meaning of that term, confined of course by the statutory text
and Supreme Court guidance recognizing the outer limits of the
agencies' authorities. See, e.g., Rapanos, 547 U.S. at 758 (Roberts,
C.J., concurring) (``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
in developing some notion of an outer bound to the reach of their
authority.'') (emphasis in original). With this action, the agencies
are finalizing a new definition of ``waters of the United States.''
 As discussed in Section II.E, the agencies conclude that this final
rule clearly establishes the scope of jurisdictional waters under the
CWA consistent with the legislative history and text of the statute and
Supreme Court case law and provides greater regulatory predictability
than the 2019 Rule regulatory text as interpreted by the Supreme Court
and implemented through agency guidance. This final rule replaces the
2019 Rule.
 With respect to the CWA section 404 permitting program for the
discharge of dredged and fill material, the agencies recognize that
this final rule could affect approved jurisdictional determinations
(AJDs) issued before the 2015 Rule or in States where the 2015 Rule was
not in effect due to litigation, under the 2015 Rule, or under the 2019
Rule. An AJD is a document issued by the Corps stating the presence or
absence 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 before
the expiration date or a District Engineer identifies specific
geographic areas with rapidly changing environmental conditions that
merit re-verification on a more frequent basis. See U.S. Army Corps of
Engineers, Regulatory Guidance Letter No. 05-02, Sec. 1(a), p. 1 (June
2005) (RGL 05-02). The possessor of a valid AJD may request that the
Corps reassess a parcel and grant a new AJD before the five-year
expiration date. An AJD constitutes a final agency action pursuant to
the agencies' definition of ``waters of the United States'' at the time
of its issuance. See Hawkes, 136 S. Ct. at 1814. This final rule does
not invalidate an AJD that was issued before the 2015 Rule or in States
where the 2015 Rule was not in effect due to litigation, under the 2015
Rule, or under the 2019 Rule. As such, these AJDs will remain valid
until the expiration date unless one of the criteria for revision is
met under RGL 05-02, or the recipient
[[Page 22332]]
of such an AJD requests that a new AJD be issued pursuant to this final
rule.
 Preliminary jurisdictional determinations (PJDs) issued by the
Corps, however, are merely advisory in nature, make no legally binding
determination of jurisdiction, and have no expiration date. See 33 CFR
331.2; see also U.S. Army Corps of Engineers, Regulatory Guidance
Letter No. 16-01 (October 2005). PJDs do not definitively state whether
waters of the United States are present on a parcel. See Hawkes, 136 S.
Ct. at 1812. However, as with AJDs, a recipient of a PJD may request a
new PJD or an AJD be issued under this final rule.
 This final rule should not significantly affect the scope of waters
over which the Corps retains permitting authority in States that have
assumed the CWA section 404 dredged or fill material permit program
pursuant to section 404(g), or the waters over which the Corps would
retain permitting authority should States and Tribes assume the program
in the future. When States or Tribes assume administration of the
section 404 program, the Corps retains administration of permits in
certain waters. 33 U.S.C. 1344(g). The scope of CWA jurisdiction as
defined by ``waters of the United States'' is distinct from the scope
of waters over which the Corps retains authority following State or
tribal assumption. The Corps-retained waters are identified during
approval of a State or tribal section 404 program, and any
modifications are approved through a formal EPA process. 40 CFR 233.36.
The way in which the Corps identifies waters to be retained was most
recently addressed on July 30, 2018, in a memorandum from R.D. James,
Assistant Secretary of the Army (Civil Works).\65\ The EPA also intends
to clarify the issue in a separate ongoing rulemaking process designed
to facilitate State and tribal assumption of the section 404 program.
The scope of waters assumed by States or Tribes that are granted
permitting authority under section 404(g) is dependent on the
definition of ``waters of the United States,'' and will change with
this final rule. For the States that already have section 404 programs
(Michigan and New Jersey), those States have corresponding State
wetland permitting programs that may apply in State waters that will no
longer be jurisdictional under the final rule.
---------------------------------------------------------------------------
 \65\ The memorandum is available at https://www.army.mil/e2/c/downloads/525981.pdf.
---------------------------------------------------------------------------
 For the proposed rule, the agencies conducted a series of analyses
to better understand the potential effects across CWA programs
associated with a revised definition of ``waters of the United
States.'' The agencies solicited comment on all aspects of the analyses
performed and published in support of the proposed rule, including the
assumptions made, information used, and the three case studies
presented in the economic analysis. The agencies further requested that
commenters provide any data that could assist the agencies in
evaluating and characterizing potential effects of the proposed rule.
The agencies have incorporated additional information on tribal
programs, updated the aquatic resource analysis, and have made other
changes, particularly in light of the final rule repealing the 2015
Rule and recodifying the pre-existing regulations (the 2019 Rule). The
2019 Rule was finalized between the proposed and final rulemaking
phases of this rule and changed the baseline for the analyses and
discussion of potential effects on aquatic resources, CWA programs, and
costs. The agencies note that the final rule is not based on the
information in the agencies' economic analysis or resource and
programmatic assessment. See, e.g., NAHB, 682 F.3d at 1039-40. This
information was not used to establish the new regulatory text for the
definition of ``waters of the United States.''
 As discussed in Section IV and in the proposed rule preamble (84 FR
4200), the agencies are not aware of any map or dataset that accurately
or with any precision portrays the scope of CWA jurisdiction at any
point in the history of this complex regulatory program. Establishing a
mapped baseline from which to assess regulatory changes is likewise
impracticable at this time, just as it was when the agencies finalized
the 2015 Rule.\66\ The challenge of identifying an accurate baseline is
further complicated by a long history of an evolving definition of
``waters of the United States.'' As summarized in Section II, what was
understood about the potential scope of CWA jurisdiction changed in the
1970s following National Resources Defense Council, Inc. v. Callaway,
392 F. Supp. 685 (D.D.C. 1975), in the mid-1980s with Riverside Bayview
and regulatory updates, in 2001 with the landmark SWANCC decision, in
2006 with the fractured Rapanos decision, in 2007 and 2008 with the
agencies' attempts to discern the meaning of the Rapanos decision
through guidance and throughout the ensuing decade of litigation that
tested those interpretations, in 2015 with a major rulemaking to
redefine the operative phrase ``waters of the United States'' and
throughout the complex litigation following that rulemaking, and in
2019 with a rule to repeal the 2015 Rule and recodify pre-existing
regulations. As the Chief Justice of the Supreme Court succinctly
observed in 2016, ``[i]t is often difficult to determine whether a
particular piece of property contains waters of the United States . . .
.'' Army Corps of Eng'rs v. Hawkes Co., 136 S. Ct. at 1812. Given the
complicated history of ``waters of the United States,'' the agencies
are not aware of any means to quantify changes in CWA jurisdiction with
any precision that may or may not occur as a result of this final rule.
---------------------------------------------------------------------------
 \66\ See U.S. EPA and Department of the Army, Response to
Comments of the EPA-Army Clean Water Rule at Topic 8: Tributaries p.
442 (May 20, 2015) (``2015 Rule RTC'') (Docket ID: EPA-HQ-OW-2011-
0880-20872), available at https://www.regulations.gov/document?D=EPA-HQ-OW-2011-0880-20872.(``The agencies do not have
maps depicting waters of the United States under either present
regulatory standards or those in the final rule.''); see also id. at
593 (`[M]aps of all the jurisdictional or non-jurisdictional waters
are not feasible[.]'').
---------------------------------------------------------------------------
 The agencies acknowledge that they faced criticism from many
commenters regarding the accuracy and assumptions they made when
attempting to estimate changes in jurisdiction for the 2015 Rule's
economic analysis (EA), which was then utilized for a portion of the
proposed rule EA and the 2019 Rule EA. For the 2015 Rule EA, the
agencies reviewed Corps approved jurisdictional determinations made
under pre-2015 Rule practice to evaluate how the jurisdictional status
of those waters might change under the 2015 Rule. Other commenters on
the proposed rule critiqued the agencies for not repeating the analysis
used to support the 2015 Rule's EA. The agencies have determined that
the analysis of approved jurisdictional determinations conducted for
the 2015 Rule EA may have incorrectly assumed that the 2015 Rule would
affect entities regulated under the CWA in direct proportion to the
percent change in positive jurisdictional determinations. This
proportional assumption could have yielded overestimates of costs and
benefits of the rule. Thus, the agencies have determined that
conducting such an analysis for this final rule would not be
appropriate.
 In addition, some commenters questioned the adequacy of the
agencies' Resource and Programmatic Assessment (RPA) analyses for the
proposed rule, primarily because the agencies did not use the NHD or
NWI, even heavily caveated. Other commenters raised concerns about the
lack of the quantification of potential changes in jurisdiction and
asserted that the agencies overestimated the ability of
[[Page 22333]]
States to regulate additional non-jurisdictional waters. Other
commenters noted that even though the NHD and the NWI have limitations,
the errors associated with the datasets would underestimate, not
overestimate, the scale of resources likely to be identified as non-
jurisdictional under the proposed rule.
 As discussed in the RPA for the final rule, the agencies attempted
to use publicly available data from national datasets (i.e., the NHD
and the NWI) to estimate the potential extent of aquatic resources
across the country before publishing the proposed rule. The agencies
ultimately concluded that the limitations of the datasets (e.g., errors
of omission, errors of commission, positional inaccuracies,
misclassification of flow regime, different definitions compared to
both existing and proposed regulations) precluded using the NHD and the
NWI to quantify the potential extent of waters whose CWA jurisdictional
status could change under the proposed revised definition. Because
these limitations still exist, the agencies decided to qualitatively
describe the potential effects of this final rule relative to the
baseline of the 2019 Rule as implemented.
 Some commenters stated that the RPA and the EA for the proposed
rule thoroughly addressed the potential impacts of the proposed revised
definition, correctly acknowledged the technical limitations of the
analysis and datasets, accurately noted that the avoided costs of the
proposal far outweighed any foregone benefits it may have, and agreed
with the agencies' decision not to rely on flawed data to perform
comparative analyses of the proposed regulatory changes. Other
commenters expressed support for the RPA's comprehensive analysis of
the potential implications of the revised definition for all relevant
CWA programs and the interplay between relevant State and federal
regulations.
 Recognizing that there will be limitations with any approach, in
the RPA and EA for the final rule the agencies describe how the revised
definition compares to the baseline of the 2019 Rule as implemented
(i.e., the pre-2015 regulations that were recodified in 2019, and as
interpreted by the Supreme Court and implemented consistent with those
decisions and informed by agency guidance). See 84 FR 56626 (Oct. 22,
2019). The documents outline the agencies' assessment of the potential
effects of the revised definition on types of aquatic resources (e.g.,
wetlands, tributaries, impoundments) across the country and on CWA
programs, and the RPA provides further information on programs
addressing aquatic resource quality under other Federal statutes. To
further inform the final rule and in an effort to respond to comments
received on the proposed rule analyses, the agencies conducted
additional research on current State and tribal laws and programs to
better understand how States and Tribes already regulate waters within
their borders. Descriptions of State programs are in Appendix A of the
RPA, and descriptions of tribal programs are in Appendix B of the RPA.
 To assess the potential effects of the rule on aquatic resources,
the agencies examined data records in the Corps' Operation and
Maintenance Business Information Link, Regulatory Module (ORM2)
database that documents Corps decisions regarding the jurisdictional
status of various aquatic resource types (i.e., jurisdictional
determinations). The aquatic resource types used in ORM2 generally
track the Rapanos Guidance (e.g., ``relatively permanent waters,''
``non-relatively permanent waters'') but do not directly correlate with
the terms used in the final rule, with limited exceptions. For the
final rule, the agencies updated their analysis from the proposal RPA
and EA to reflect data from ORM2 for fiscal years 2013-2018. Because of
various limitations in accurately estimating a change in CWA
jurisdiction, as described in Section IV of this notice, and
uncertainties regarding the way States and Tribes might respond
following a change in the definition of ``waters of the United
States,'' many of the potential effects of the final rule are discussed
qualitatively, and some are discussed quantitatively where possible.
 As discussed in the RPA and the EA for the final rule, the agencies
also evaluated potential effects of the final rule across CWA
regulatory programs. The RPA and EA describe certain potential short-
term effects for CWA regulatory programs; however, the potential long-
term effects will depend on whether or how States and Tribes choose to
modify their existing regulatory programs. For example, States may
elect to make changes to their statutes or regulations to regulate
waters that are no longer jurisdictional under the final rule. As
discussed more fully in the EA, complete State ``gap-filling'' could
result in a zero-net impact in the long-run.
 Regarding the permitting programs under sections 402 and 404 of the
CWA, the final rule will reduce the scope of waters subject to CWA
permitting compared with the baseline of the 2019 Rule as implemented.
For instance, the 2019 Rule, as implemented, would regulate certain
ephemeral streams found to have a significant nexus with traditional
navigable waters according to the 2008 Rapanos Guidance, whereas the
revised definition in this final rule categorically excludes ephemeral
features. Because fewer waters and wetlands are federally regulated
under this rule relative to the 2019 Rule as implemented, the agencies
anticipate that the regulated public would need to prepare fewer CWA
permit applications. Additionally, some facilities currently
discharging under a CWA section 402 permit may no longer be required to
obtain permit coverage under federal law where there is a
jurisdictional change to the receiving water and the receiving water
does not convey pollutants from a point source to a water of the United
States. The agencies note that they retain section 402 permitting
authority over discharges that reach jurisdictional waters through
conveyances, such as non-jurisdictional waters. In some section 402
permits, water quality-based effluent limitations may be modified,
subject to applicable anti-backsliding permit requirements, where a
facility discharges to a water that is non-jurisdictional under the
final rule, but the pollutants discharged still reach a jurisdictional
water. Any permittee with questions about the effects of this rule
should consult their permitting authority, as State law may be broader
than federal authority under the CWA. A reduction in jurisdictional
waters under the final rule may reduce the number of federal permits
that require a section 401 certification and may reduce the
applicability of the section 311 program and associated Oil Spill
Liability Trust Fund, as discussed in more detail in the EA and RPA.
 A change in the scope of CWA jurisdiction could affect existing and
future State or tribal CWA section 303(d) lists and Total Maximum Daily
Load (TMDL) restoration plans under section 303(d). For example, some
States or Tribes may not assess non-jurisdictional waters, and thus may
identify fewer waters as impaired and may develop fewer TMDLs. States
may continue to apply their own State law-based programs to identify
and restore impaired waters, although this activity would not be
required under the CWA for waters that are not jurisdictional under the
final rule. The agencies expect that States will, however, be able to
focus their section 303(d) financial resources on a more targeted range
of waters and could accelerate adoption of plans and standards on
waters that may
[[Page 22334]]
have more ecological value. If Western States, for example, do not need
to assess dry washes in the desert and establish CWA water quality
standards for those typically dry ``waters,'' they can focus their
research and restoration resources on waters with more substantial
aquatic habitat. For additional discussion of potential effects on
State and tribal water quality standards and section 303(d) programs,
see the RPA.
 Some commenters on the proposed rule raised concerns about its
potential effects on CWA financial assistance programs. The agencies do
not anticipate that the final rule will affect the EPA's current CWA
financial assistance programs. With respect to CWA sections 106 and 319
grant programs, the authorizing language and the range of programmatic
activities are sufficiently broad that they have long addressed both
jurisdictional and non-jurisdictional waters, so it is unlikely that a
change in the definition of ``waters of the United States'' will affect
the programs and funding allocations.
 Other commenters raised concerns about potential effects of the
proposed rule on sources of drinking water. Drinking water regulations
under the Safe Drinking Water Act (SDWA) will continue to apply to
water delivered by public water systems, with the goal of protecting
public health. The Drinking Water State Revolving Fund is available to
help fund State source water protection programs and finance
improvements to drinking water utilities. Overall, the potential
effects of a change in CWA jurisdiction on drinking water quality will
depend on whether activities affecting non-jurisdictional waters also
affect the quality of the water at a drinking water utility's water
intake, and the capabilities of individual drinking water utilities to
respond to a potential change in source water quality.
 In the EA for the proposed rule, the agencies applied a two-stage
analysis to make the best use of limited local and national level water
resource information in their effort to assess the potential
implications of the proposal. When the proposed rule was published, the
agencies determined that the outputs of this two-stage analysis were
the best way to illustrate the potential overall impact of the proposed
rule compared to the 2015 Rule being in effect nationwide (i.e., the
sum effect of both stages) and the 2015 Rule not being in effect (i.e.,
second stage only). In the ``Stage 1'' analysis in the EA for the
proposed rule, the agencies used the EA for the 2015 Rule as a starting
point, made several updates, and developed a quantitative assessment
limited to Stage 1. Because the 2015 Rule was repealed (84 FR 56626)
between the proposed and final rule stages of this rulemaking, the EA
for this final rule does not contain the Stage 1 quantitative analysis
comparing the 2015 Rule with the pre-existing regulations.
 The EA for the final rule incorporates an updated analysis
depicting how States may respond to a change in CWA jurisdiction. This
analysis of State authorities and programs was initially presented in
the EA for the related rulemaking effort, Economic Analysis for the
Final Rule: Definition of ``Waters of the United States''--
Recodification of Pre-Existing Rules. Potential State responses to a
change in the definition of a ``water of the United States'' fall along
a continuum and depend on legal and other constraints. Some States rely
on the federal CWA to regulate impacts to wetlands and other aquatic
resources. These States may be affected by this action; however,
nothing in the CWA or this final rule prevents or precludes states from
regulating more stringently than federal requirements. Some States,
based on limitations established in State law, cannot currently
regulate a more expansive set of waters than those subject to the
federal CWA definition of ``waters of the United States.'' In contrast,
States that regulate surface waters and wetlands as broadly as or more
broadly than the 2019 Rule as implemented, independently of the scope
of the federal CWA, may not be affected by this action. Complete State
``gap-filling'' could result in no change in compliance costs to the
regulated community and no change in environmental benefits (that is,
neither avoided costs nor forgone benefits would occur), suggesting a
zero-net impact in the long-run. States that fall between these
extremes are evaluated by either including or excluding them from the
estimates of cost savings and forgone benefits. In reality, some States
may regulate only a subset of affected waters, but the agencies did not
have sufficient information to incorporate that level of detail into
the analysis.
 Another potential outcome of the change in CWA jurisdiction is that
State governments may be able to find more efficient ways of managing
local resources than the Federal government, consistent with the theory
of ``environmental federalism'' as described in the EA for the final
rule. Depending on the value of a newly characterized non-
jurisdictional water, States may or may not choose to regulate that
water and the compliance costs and environmental benefits of its
regulation could increase or decrease, respectively. In either case,
however, net benefits would increase, assuming that a State can more
efficiently allocate resources towards environmental protection due to
local knowledge of amenities and constituent preferences. As effective
regulation requires political capital and fiscal resources, however,
the likely best indication of the way in which States will exercise
their authority as the Federal government changes the scope of CWA
jurisdiction is the way in which they have exercised authority in the
past and whether the infrastructure to manage the regulatory programs
already exists. The qualitative analysis is intended to provide
information on the likely direction of the potential effects of the
final rule on CWA regulatory programs.
 In addition, the agencies conducted case studies in three major
watersheds (Ohio River basin, Lower Missouri River basin, and Rio
Grande River basin) to provide information for a quantitative
assessment of the potential effects of the final rule. The case studies
considered potential ecological effects, and their accompanying
potential economic effects for programs implemented pursuant to
sections 311, 402, and 404 of the CWA. Because of data limitations, the
agencies were able to provide national-level estimates of the potential
avoided permit and mitigation costs and forgone benefits for only the
CWA section 404 program. The agencies developed several scenarios to
estimate the national annual avoided costs and foregone benefits of the
CWA section 404 program under the final rule using different
assumptions about potential State dredged and fill regulation of
waters. Using the same methodologies employed in the case studies,
under scenarios assuming State regulation of dredged and fill
activities in newly non-jurisdictional waters, the agencies estimate
that the final rule would produce annual avoided costs ranging between
$109 million to $264 million and annual forgone benefits ranging
between from $55 million to $63 million. Under the scenario that
assumes that no States will regulate dredged and fill activities in
newly non-jurisdictional waters, an outcome the agencies believe is
unlikely, the agencies estimate the final rule would produce annual
avoided costs ranging from $245 million to $513 million, and annual
forgone benefits are estimated at $173 million.
[[Page 22335]]
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review; Executive
Order 13563: Improving Regulation and Regulatory Review
 This action is an ``economically 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. In addition, the agencies
prepared an analysis of the potential costs and benefits associated
with this action. This analysis is contained in the Economic Analysis
for the Navigable Waters Protection Rule: Definition of ``Waters of the
United States,'' which is available in the docket and briefly
summarized in Section V. Additional analysis can be found in the
Resource and Programmatic Assessment for the Navigable Waters
Protection Rule: Definition of ``Waters of the United States'' which is
also available in the docket.
 While the economic analysis is informative in the rulemaking
context, the agencies are not relying on the economic analysis
performed pursuant to Executive Orders 12866 and 13563 and related
procedural requirements as a basis for this final rule. See, e.g.,
NAHB, 682 F.3d at 1039-40 (noting that the quality of an agency's
economic analysis can be tested under the APA if the ``agency decides
to rely on a cost-benefit analysis as part of its rulemaking'').
B. Executive Order 13771: Reducing Regulation and Controlling
Regulatory Costs
 Pursuant to Executive Order 13771 (82 FR 9339, February 3, 2017),
this final rule is a deregulatory action. Details on the estimated cost
savings of this rule can be found in the Economic Analysis in the
docket for this rule.
C. Paperwork Reduction Act
 This action does not impose any new information collection burden
under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. OMB has
previously approved the information collection activities contained in
the existing regulations and has assigned OMB control numbers 2050-0021
and 2050-0135 for the CWA section 311 program and 2040-0004 for the CWA
section 402 program. For the CWA section 404 program, the current OMB
approval number for information requirements is maintained by the Corps
(OMB approval number 0710-0003). However, there are no new approval or
application processes required as a result of this rulemaking that
necessitate a new Information Collection Request (ICR).
D. Regulatory Flexibility Act
 The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
 For purposes of assessing the impacts of this final rule on small
entities, ``small entity'' is defined as: (1) A small business that is
a small industrial entity as defined in the U.S. Small Business
Administration's size standards (see 13 CFR 121.201); (2) a small
governmental jurisdiction that is a government of a city, county, town,
school district, or special district with a population of less than
50,000; or (3) a small organization that is any not-for-profit
enterprise that is independently owned and operated and is not dominant
in its field.
 The purpose of the RFA is ``to fit regulatory and informational
requirements to the scale of the businesses, organizations and
governmental jurisdictions subject to the regulation.'' 5 U.S.C. 601.
Small entities subject to this final rule are largely those entities
whose activities are directly covered by the CWA sections 402, 404, and
311 programs. The final rule is expected to result in fewer entities
subject to these programs, and a reduced regulatory burden for many of
the entities that will still be subject to these programs. As a result,
small entities subject to these regulatory programs are unlikely to
suffer adverse impacts as a result of regulatory compliance.
 As addressed in the Economic Analysis for the final rule, narrowing
the scope of CWA regulatory jurisdiction over waters may result in a
reduction in the ecosystem services provided by some waters, and as a
result, some entities may be adversely impacted. Some business sectors
that depend on habitat, such as those catering to hunters or anglers,
or that require water treatment to meet production needs, could
experience a greater impact relative to other sectors. Potential
changes in ecosystem services are likely to be small, infrequent, and
dispersed over wide geographic areas, thereby limiting the significance
of these impacts on these business sectors. In addition, States and
Tribes may already address waters potentially affected by a revised
definition, thereby reducing forgone benefits.
 The sectors likely to be most impacted by the rule are mitigation
banks and companies that provide aquatic resource restoration services.
Because fewer waters would be subject to the CWA regulation under the
final rule than are subject to regulation under the 2019 Rule, there
may be a reduction in demand for mitigation and restoration services
under the section 404 permitting program. Assessing impacts to this
sector is problematic, however, because this sector lacks a precise SBA
small business definition, and many of the businesses that fall within
this sector are also classified under various other North American
Industry Classification System (NAICS) categories. Furthermore, impacts
to this sector would not be the direct result of these businesses
complying with the final rule, rather, they would be the indirect
result of other entities no longer being required to mitigate for
discharges of dredged or fill material into waters that would no longer
be jurisdictional under the final rule. In addition, potential impacts
would be lessened when accounting for State and tribal dredged and fill
programs that would necessitate the purchase of mitigation credits or
through the actions of States and Tribes that choose to regulate their
wetlands under State or tribal law. For a more detailed discussion see
the RFA section of the Economic Analysis for the final rule.
 The agencies certify that this action will not have a significant
economic impact on a substantial number of small entities under the
RFA. In making this determination, the impact of concern is any
significant adverse economic impact on small entities. An agency may
certify that a rule will not have a significant economic impact on a
substantial number of small entities if the rule relieves regulatory
burden, has no net burden, or otherwise has a positive economic effect
on the small entities subject to the rule. As documented in the
Economic Analysis for the final rule, the agencies do not expect the
cost of the rule to result in adverse impact to a significant number of
small entities, since the rule is expected to result in net cost
savings for all entities affected by this rule. The agencies have
therefore concluded that this action will relieve regulatory burden to
small entities.
[[Page 22336]]
E. Unfunded Mandates Reform Act
 This final rule does not contain any unfunded mandate as described
in the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 1531-1538,
and does not significantly or uniquely affect small governments. The
definition of ``waters of the United States'' applies broadly to CWA
programs. The final action imposes no enforceable duty on any State,
local, or tribal governments or the private sector, and does not
contain regulatory requirements that significantly or uniquely affect
small governments.
F. 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 implications for
State and local governments under the terms of Executive Order 13132
(64 FR 43255, August 10, 1999). State and local governments were
engaged in a 60-day Federalism consultation at the outset of rule
development starting on April 19, 2017. All letters received by the
agencies during Federalism consultation may be found on in the docket
at EPA Docket Id No. EPA-HQ-OW-2018-0149-0088, available at https://www.regulations.gov/document?D=EPA-HQ-OW-2018-0149-0088.
 The agencies held nineteen Federalism meetings between April 19 and
June 16, 2017. Seventeen intergovernmental associations, including nine
of the ten organizations identified in EPA's 2008 E.O. 13132 Guidance,
attended the initial Federalism consultation meeting, as well as
several associations representing State and local governments.
Organizations in attendance included: The National Governors
Association, the National League of Cities, the National Association of
Counties, the U.S. Conference of Mayors, the Council of State
Governments, the National Conference of State Legislatures, the County
Executives of America, the National Association of Towns and Townships,
the Environmental Council of the States, the Western Governors
Association, the National Association of Clean Water Agencies, the
Association of Clean Water Administrators, the National Association of
State Departments of Agriculture, the Association of State Wetlands
Managers, the Association of State Floodplain Managers, the National
Water Resources Association, the State/Local Legal Center, and several
members of EPA's Local Government Advisory Committee (LGAC).
 The LGAC met 10 times during this period to address the charge
given to its members by the EPA Administrator on a revised rule and
completed a report addressing the questions outlined in their charge.
The July 14, 2017, final report can be obtained here: https://www.epa.gov/sites/production/files/2017-07/documents/lgac-final-wotusreport-july2017.pdf and in the docket as attachment to EPA Docket
Id No. EPA-HQ-OW-2018-0149-0088, available at https://www.regulations.gov/document?D=EPA-HQ-OW-2018-0149-0088.
 The agencies then conducted additional outreach to States prior to
proposing the rule to ensure that the agencies could hear the
perspectives on how the agencies might revise the definition of
``waters of the United States'' from State co-regulators. The agencies
held two additional webinars, the first for Tribes, States, and local
governments on December 12, 2017; and one for States on February 20,
2018. In addition, one in-person meeting to seek technical input on the
development of the proposed rule was held with a group of nine states
(Arizona, Arkansas, Florida, Iowa, Maryland, Minnesota, Oregon,
Pennsylvania, and Wyoming) on March 8 and 9, 2018.
 These meetings and the letters provided by representatives provided
a wide and diverse range of interests, positions, comments, and
recommendations to the agencies. 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-2018-0149)
for this final rule.
 Following publication of the proposed rule, the agencies held four
additional in-person meetings with State representatives to answer
clarifying questions about the proposal, and to discuss implementation
considerations and State interest in working with the agencies to
develop geospatial datasets of water resources as articulated in the
preamble to the proposed 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. This rule does not
impose any new costs or other requirements on states, preempt state
law, or limit states' policy discretion; rather, it provides more
discretion for states as to how best to manage waters under their sole
jurisdiction. Executive Order paras. (6)(b) and (6)(c). As discussed in
the earlier sections of the notice, this final rule establishes a clear
boundary between waters subject to federal regulatory requirements
under the CWA and those that States may solely manage under their
independent authorities. 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. The rule
preserves State authority to choose whether or not to regulate waters
that are not waters of the United States under the CWA. The agencies
believe that the requirements of the Executive Order have been
satisfied in any event.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
 Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (65 FR 67249, Nov. 9, 2000), requires
the agencies to develop an accountable process to ensure ``meaningful
and timely input by tribal officials in the development of regulatory
policies that have tribal implications.'' This action has tribal
implications. However, it will neither impose substantial direct
compliance costs on federally recognized tribal governments, nor
preempt tribal law.
 During tribal consultation and engagement efforts and in tribal
comments on the proposed rule, many Tribes expressed concern that the
proposed rule would or could adversely impact tribal waters. Two tribes
supported the proposed rule and noted that it would increase the
tribes' ability to manage and regulate their own Reservation lands. The
agencies acknowledge that because they generally implement CWA programs
on tribal lands, a reduced scope of CWA jurisdiction will affect Tribes
differently than it will affect States. Currently, of the Tribes that
are eligible, most have not received treatment in a manner similar to a
state (TAS) status to administer CWA regulatory programs. While some
Tribes have established tribal water programs under tribal law or have
the authority to establish tribal programs under tribal law, many
Tribes may lack the capacity to create a tribal water program under
tribal law, to
[[Page 22337]]
administer a program, or to expand programs that currently exist. Other
Tribes may rely on the Federal government for enforcement of water
quality violations. Nonetheless, the rule preserves tribal authority to
choose whether or not to regulate waters that are not covered under the
CWA. Any decision by the Tribes to protect beyond the limits of the CWA
is not compelled by the statute or by this final rule.
 The EPA consulted with tribal officials under the EPA Policy on
Consultation and Coordination with Indian Tribes early in the process
of developing this action to permit them to have meaningful and timely
input into its development. The Department of the Army participated in
the consultation process and further engagement with Tribes. All
letters received by the agencies during tribal consultation may be
found in the docket for this action, Docket Id. No. EPA-HQ-OW-2018-
0149.
 The EPA initiated a tribal consultation and coordination process
before proposing this rule by sending a ``Notification of Consultation
and Coordination'' letter on April 20, 2017, to all of the 567 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 held two
identical webinars concerning this matter for tribal representatives on
April 27 and May 18, 2017. Tribes and tribal organizations sent 44 pre-
proposal comment letters to the agencies as part of the consultation
process. Of those Tribes requesting consultation, the agencies met with
nine Tribes at a staff-level and with three Tribes at a leader-to-
leader level pre-proposal. The agencies continued engagement with
Tribes after the end of the formal consultation, including at national
update webinars on December 12, 2017, and February 20, 2018, and an in-
person tribal co-regulators workshop on March 6 and 7, 2018.
 Following the publication of the proposed rule, the agencies held
four in-person meetings with tribal representatives to answer
clarifying questions about the proposal, and to discuss implementation
considerations and tribal interest in working with the agencies to
develop geospatial datasets of water resources as articulated in the
preamble to the proposed rule. In addition, the agencies continued to
meet with individual Tribes requesting consultation or engagement
following publication of the proposed rule, holding staff-level
meetings with four Tribes and leader-to-leader level meetings with
eight Tribes post-proposal. The agencies also continued engaging with
Tribes and tribal organizations via listening sessions at regional and
national tribal meetings. In total, the agencies met with 21 individual
Tribes requesting consultation, holding leader-to-leader level
consultation meetings with 11 individual tribes and staff-level
meetings with 13 individual tribes (the agencies met with some tribes
more than once). The agencies have prepared a report summarizing the
consultation and further engagement with tribal nations. This report,
Summary Report of Tribal Consultation and Engagement for the Navigable
Waters Protection Rule: Definition of ``Waters of the United States''
(Docket Id. No. EPA-HQ-OW-2018-0149), is available in the docket for
this final rule.
 As required by section 7(a), the EPA's Tribal Consultation Official
has certified that the requirements of the executive order have been
met in a meaningful and timely manner. A copy of the certification is
included in the docket for this action.
H. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
 This action is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because the environmental health or safety risks
addressed by this action do not present a disproportionate risk to
children.
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
 This action is not a ``significant energy action'' as defined in
Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy.
J. National Technology Transfer and Advancement Act
 This action is not subject to the National Technology Transfer and
Advancement Act of 1995 because the rule does not involve technical
standards.
K. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations
 This action is not subject to Executive Order 12898 (59 FR 7629,
February 11, 1994) because there is no significant evidence of
disproportionately high and adverse human health or environmental
effects on minority populations, low-income populations, and/or
indigenous peoples, as specified in Executive Order 12898.
L. 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. OMB has concluded that
this action is a ``major rule'' as defined by 5 U.S.C. 804(2).
List of Subjects
33 CFR Part 328
 Navigation (water), Water pollution control, Waterways.
40 CFR Part 110
 Oil pollution, Reporting and recordkeeping requirements.
40 CFR Part 112
 Oil pollution, Penalties, Reporting and recordkeeping requirements.
40 CFR Part 116
 Hazardous substances, Reporting and recordkeeping requirements,
Water pollution control.
40 CFR Part 117
 Hazardous substances, Penalties, Reporting and recordkeeping
requirements, Water pollution control.
40 CFR Part 120
 Environmental protection, Water pollution control, Waterways.
40 CFR Part 122
 Administrative practice and procedure, Confidential business
information, Environmental protection, Hazardous substances, Reporting
and recordkeeping requirements, Water pollution control.
40 CFR Part 230
 Water pollution control.
40 CFR Part 232
 Intergovernmental relations, Water pollution control.
40 CFR Part 300
 Air pollution control, Carbon monoxide, Chemicals, Environmental
protection, Greenhouse gases, Hazardous substances, Hazardous waste,
Intergovernmental relations, Lead, Natural resources, Occupational
safety and health, Oil pollution, Ozone, Penalties, Reporting and
recordkeeping requirements, Sulfur Dioxide, Superfund, Volatile organic
compounds, Water pollution control, Water supply.
[[Page 22338]]
40 CFR Part 302
 Air pollution control, Chemicals, Hazardous substances, Hazardous
waste, Intergovernmental relations, Natural resources, Reporting and
recordkeeping requirements, Superfund, Water pollution control, Water
supply.
40 CFR Part 401
 Waste treatment and disposal, Water pollution control.
 Dated: January 23, 2020.
Andrew R. Wheeler,
Administrator, Environmental Protection Agency.
 Dated: January 23, 2020.
R.D. James,
Assistant Secretary of the Army (Civil Works), Department of the Army.
Title 33--Navigation and Navigable Waters
 For the reasons set forth in the preamble, title 33, chapter II of
the Code of Federal Regulations is amended as follows:
PART 328--DEFINITION OF WATERS OF THE UNITED STATES
0
1. Authority: The authority citation for part 328 is revised read as
follows: 33 U.S.C. 1251 et seq.
0
2. Section 328.3 is amended by revising paragraphs (a) through (c) and
removing paragraphs (d) through (f) to read as follows:
Sec. 328.3 Definitions.
* * * * *
 (a) Jurisdictional waters. For purposes of the Clean Water Act, 33
U.S.C. 1251 et seq. and its implementing regulations, subject to the
exclusions in paragraph (b) of this section, the term ``waters of the
United States'' means:
 (1) The territorial seas, and waters which are currently used, or
were used in the past, or may be susceptible to use in interstate or
foreign commerce, including waters which are subject to the ebb and
flow of the tide;
 (2) Tributaries;
 (3) Lakes and ponds, and impoundments of jurisdictional waters; and
 (4) Adjacent wetlands.
 (b) Non-jurisdictional waters. The following are not ``waters of
the United States'':
 (1) Waters or water features that are not identified in paragraph
(a)(1), (2), (3), or (4) of this section;
 (2) Groundwater, including groundwater drained through subsurface
drainage systems;
 (3) Ephemeral features, including ephemeral streams, swales,
gullies, rills, and pools;
 (4) Diffuse stormwater run-off and directional sheet flow over
upland;
 (5) Ditches that are not waters identified in paragraph (a)(1) or
(2) of this section, and those portions of ditches constructed in
waters identified in paragraph (a)(4) of this section that do not
satisfy the conditions of paragraph (c)(1) of this section;
 (6) Prior converted cropland;
 (7) Artificially irrigated areas, including fields flooded for
agricultural production, that would revert to upland should application
of irrigation water to that area cease;
 (8) 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 conditions of paragraph (c)(6) of
this section;
 (9) Water-filled depressions constructed or excavated in upland or
in non-jurisdictional waters incidental to mining or construction
activity, and pits excavated in upland or in non-jurisdictional waters
for the purpose of obtaining fill, sand, or gravel;
 (10) Stormwater control features constructed or excavated in upland
or in non-jurisdictional waters to convey, treat, infiltrate, or store
stormwater run-off;
 (11) 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
 (12) Waste treatment systems.
 (c) Definitions. In this section, the following definitions apply:
 (1) Adjacent wetlands. The term adjacent wetlands means wetlands
that:
 (i) Abut, meaning to touch at least at one point or side of, a
water identified in paragraph (a)(1), (2), or (3) of this section;
 (ii) Are inundated by flooding from a water identified in paragraph
(a)(1), (2), or (3) of this section in a typical year;
 (iii) Are physically separated from a water identified in paragraph
(a)(1), (2), or (3) of this section only by a natural berm, bank, dune,
or similar natural feature; or
 (iv) Are physically separated from a water identified in paragraph
(a)(1), (2), or (3) of this section 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 identified in paragraph (a)(1), (2), or (3) of this
section in a typical year, such as through a culvert, flood or tide
gate, pump, or similar artificial feature. An adjacent wetland is
jurisdictional in its entirety when a road or similar artificial
structure divides the wetland, as long as the structure allows for a
direct hydrologic surface connection through or over that structure in
a typical year.
 (2) Ditch. The term ditch means a constructed or excavated channel
used to convey water.
 (3) Ephemeral. The term ephemeral means surface water flowing or
pooling only in direct response to precipitation (e.g., rain or snow
fall).
 (4) High tide line. The term 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.
 (5) Intermittent. The term intermittent means surface water flowing
continuously during certain times of the year and more than in direct
response to precipitation (e.g., seasonally when the groundwater table
is elevated or when snowpack melts).
 (6) Lakes and ponds, and impoundments of jurisdictional waters. The
term lakes and ponds, and impoundments of jurisdictional waters means
standing bodies of open water that contribute surface water flow to a
water identified in paragraph (a)(1) of this section in a typical year
either directly or through one or more waters identified in paragraph
(a)(2), (3), or (4) of this section. A lake, pond, or impoundment of a
jurisdictional water does not lose its jurisdictional status if it
contributes surface water flow to a downstream jurisdictional water in
a typical year through a channelized non-jurisdictional surface water
feature, through a culvert, dike, spillway, or similar artificial
feature, or through a debris pile, boulder field, or similar natural
feature. A lake or pond, or impoundment of a jurisdictional water
[[Page 22339]]
is also jurisdictional if it is inundated by flooding from a water
identified in paragraph (a)(1), (2), or (3) of this section in a
typical year.
 (7) Ordinary high water mark. The term ordinary high water mark
means that line on the shore established by the fluctuations of water
and indicated by physical characteristics such as a 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.
 (8) Perennial. The term perennial means surface water flowing
continuously year-round.
 (9) Prior converted cropland. The term prior converted cropland
means any area that, prior to December 23, 1985, was drained or
otherwise manipulated for the purpose, or having the effect, of making
production of an agricultural product possible. EPA and the Corps will
recognize designations of prior converted cropland made by the
Secretary of Agriculture. An area is no longer considered prior
converted cropland for purposes of the Clean Water Act when the area is
abandoned and has reverted to wetlands, as defined in paragraph (c)(16)
of this section. Abandonment occurs when prior converted cropland is
not used for, or in support of, agricultural purposes at least once in
the immediately preceding five years. For the purposes of the Clean
Water Act, the EPA Administrator shall have the final authority to
determine whether prior converted cropland has been abandoned.
 (10) Snowpack. The term snowpack means 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).
 (11) Tidal waters and waters subject to the ebb and flow of the
tide. The terms tidal waters and waters subject to the ebb and flow of
the tide mean 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 and waters subject to the ebb and flow of the
tide 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.
 (12) Tributary. The term tributary means a river, stream, or
similar naturally occurring surface water channel that contributes
surface water flow to a water identified in paragraph (a)(1) of this
section in a typical year either directly or through one or more waters
identified in paragraph (a)(2), (3), or (4) of this section. A
tributary must be perennial or intermittent in a typical year. The
alteration or relocation of a tributary does not modify its
jurisdictional status as long as it continues to satisfy the flow
conditions of this definition. A tributary does not lose its
jurisdictional status if it contributes surface water flow to a
downstream jurisdictional water in a typical year through a channelized
non-jurisdictional surface water feature, through a subterranean river,
through a culvert, dam, tunnel, or similar artificial feature, or
through a debris pile, boulder field, or similar natural feature. The
term tributary includes a ditch that either relocates a tributary, is
constructed in a tributary, or is constructed in an adjacent wetland as
long as the ditch satisfies the flow conditions of this definition.
 (13) Typical year. The term typical year means 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.
 (14) Upland. The term upland means any land area that under normal
circumstances does not satisfy all three wetland factors (i.e.,
hydrology, hydrophytic vegetation, hydric soils) identified in
paragraph (c)(16) of this section, and does not lie below the ordinary
high water mark or the high tide line of a jurisdictional water.
 (15) Waste treatment system. The term waste treatment system
includes all components, including lagoons and treatment ponds (such as
settling or cooling ponds), designed to either convey or retain,
concentrate, settle, reduce, or remove pollutants, either actively or
passively, from wastewater prior to discharge (or eliminating any such
discharge).
 (16) Wetlands. The term wetlands means 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.
* * * * *
Title 40--Protection of Environment
 For reasons set out in the preamble, title 40, chapter I of the
Code of Federal Regulations is amended as follows:
PART 110--DISCHARGE OF OIL
0
3. The authority citation for part 110 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq., 33 U.S.C. 1321(b)(3) and
(b)(4) and 1361(a); E.O. 11735, 38 FR 21243, 3 CFR parts 1971-1975
Comp., p. 793.
0
4. Section 110.1 is amended by revising the definition of ``Navigable
waters'' and removing the definition of ``Wetlands'' to read as
follows:
Sec. 110.1 Definitions.
* * * * *
 Navigable waters means waters of the United States, including the
territorial seas, as defined in Sec. 120.2 of this chapter.
* * * * *
PART 112--OIL POLLUTION PREVENTION
0
5. The authority citation for part 112 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
6. Section 112.2 is amended by revising the definition of ``Navigable
waters'' and removing the definition of ``Wetlands'' to read as
follows:
Sec. 112.2 Definitions.
* * * * *
 Navigable waters means waters of the United States, including the
territorial seas, as defined in Sec. 120.2 of this chapter.
* * * * *
PART 116--DESIGNATION OF HAZARDOUS SUBSTANCES
0
7. The authority citation for part 116 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
8. Section 116.3 is amended by revising the definition of ``Navigable
waters'' to read as follows:
Sec. 116.3 Definitions.
* * * * *
 Navigable waters means ``waters of the United States,'' including
the territorial seas, as defined in Sec. 120.2 of this chapter.
* * * * *
PART 117--DETERMINATION OF REPORTABLE QUANTITIES FOR HAZARDOUS
SUBSTANCES
0
9. The authority citation for part 117 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq., and Executive Order 11735,
superseded by Executive Order 12777, 56 FR 54757.
[[Page 22340]]
0
10. Section 117.1 is amended by revising paragraph (i) to read as
follows:
Sec. 117.1 Definitions.
* * * * *
 (i) Navigable waters means ``waters of the United States, including
the territorial seas,'' as defined in Sec. 120.2 of this chapter.
* * * * *
0
11. Add part 120 to read as follows:
PART 120--DEFINITION OF WATERS OF THE UNITED STATES
Sec.
120.1 Purpose and scope.
120.2 Definitions.
 Authority: 33 U.S.C. 1251 et seq.
Sec. 120.1 Purpose and scope.
 Part 120 contains the definition of ``navigable waters'' and
``waters of the United States'' for purposes of the Clean Water Act, 33
U.S.C. 1251 et seq. and its implementing regulations.
Sec. 120.2 Definitions.
 For the purposes of this part, the following terms shall have the
meanings indicated:
 Navigable waters means waters of the United States, including the
territorial seas.
 Waters of the United States means:
 (1) Jurisdictional waters. For purposes of the Clean Water Act, 33
U.S.C. 1251 et seq. and its implementing regulations, subject to the
exclusions in paragraph (2) of this section, the term ``waters of the
United States'' means:
 (i) The territorial seas, and waters which are currently used, or
were used in the past, or may be susceptible to use in interstate or
foreign commerce, including waters which are subject to the ebb and
flow of the tide;
 (ii) Tributaries;
 (iii) Lakes and ponds, and impoundments of jurisdictional waters;
and
 (iv) Adjacent wetlands.
 (2) Non-jurisdictional waters. The following are not ``waters of
the United States'':
 (i) Waters or water features that are not identified in paragraph
(1)(i), (ii), (iii), or (iv) of this definition;
 (ii) Groundwater, including groundwater drained through subsurface
drainage systems;
 (iii) Ephemeral features, including ephemeral streams, swales,
gullies, rills, and pools;
 (iv) Diffuse stormwater run-off and directional sheet flow over
upland;
 (v) Ditches that are not waters identified in paragraph (1)(i) or
(ii) of this definition, and those portions of ditches constructed in
waters identified in paragraph (1)(iv) of this definition that do not
satisfy the conditions of paragraph (3)(i) of this definition;
 (vi) Prior converted cropland;
 (vii) Artificially irrigated areas, including fields flooded for
agricultural production, that would revert to upland should application
of irrigation water to that area cease;
 (viii) 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 conditions of
paragraph (3)(vi) of this definition;
 (ix) Water-filled depressions constructed or excavated in upland or
in non-jurisdictional waters incidental to mining or construction
activity, and pits excavated in upland or in non-jurisdictional waters
for the purpose of obtaining fill, sand, or gravel;
 (x) Stormwater control features constructed or excavated in upland
or in non-jurisdictional waters to convey, treat, infiltrate, or store
stormwater run-off;
 (xi) 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
 (xii) Waste treatment systems.
 (3) Definitions. In this section, the following definitions apply:
 (i) Adjacent wetlands. The term adjacent wetlands means wetlands
that:
 (A) Abut, meaning to touch at least at one point or side of, a
water identified in paragraph (1)(i), (ii), or (iii) of this
definition;
 (B) Are inundated by flooding from a water identified in paragraph
(1)(i), (ii), or (iii) of this definition in a typical year;
 (C) Are physically separated from a water identified in paragraph
(1)(i), (ii), or (iii) of this definition only by a natural berm, bank,
dune, or similar natural feature; or
 (D) Are physically separated from a water identified in paragraph
(1)(i), (ii), or (iii) of this definition 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 identified in paragraph (1)(i), (ii), or (iii) of this
definition in a typical year, such as through a culvert, flood or tide
gate, pump, or similar artificial feature. An adjacent wetland is
jurisdictional in its entirety when a road or similar artificial
structure divides the wetland, as long as the structure allows for a
direct hydrologic surface connection through or over that structure in
a typical year.
 (ii) Ditch. The term ditch means a constructed or excavated channel
used to convey water.
 (iii) Ephemeral. The term ephemeral means surface water flowing or
pooling only in direct response to precipitation (e.g., rain or snow
fall).
 (iv) High tide line. The term 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.
 (v) Intermittent. The term intermittent means surface water flowing
continuously during certain times of the year and more than in direct
response to precipitation (e.g., seasonally when the groundwater table
is elevated or when snowpack melts).
 (vi) Lakes and ponds, and impoundments of jurisdictional waters.
The term lakes and ponds, and impoundments of jurisdictional waters
means standing bodies of open water that contribute surface water flow
to a water identified in paragraph (1)(i) of this definition in a
typical year either directly or through one or more waters identified
in paragraph (1)(ii), (iii), or (iv) of this definition. A lake, pond,
or impoundment of a jurisdictional water does not lose its
jurisdictional status if it contributes surface water flow to a
downstream jurisdictional water in a typical year through a channelized
non-jurisdictional surface water feature, through a culvert, dike,
spillway, or similar artificial feature, or through a debris pile,
boulder field, or similar natural feature. A lake or pond, or
impoundment of a jurisdictional water is also jurisdictional if it is
inundated by flooding from a water identified in paragraph (1)(i),
(ii), or (iii) of this definition in a typical year.
[[Page 22341]]
 (vii) Ordinary high water mark. The term ordinary high water mark
means that line on the shore established by the fluctuations of water
and indicated by physical characteristics such as a 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.
 (viii) Perennial. The term perennial means surface water flowing
continuously year-round.
 (ix) Prior converted cropland. The term prior converted cropland
means any area that, prior to December 23, 1985, was drained or
otherwise manipulated for the purpose, or having the effect, of making
production of an agricultural product possible. EPA and the Corps will
recognize designations of prior converted cropland made by the
Secretary of Agriculture. An area is no longer considered prior
converted cropland for purposes of the Clean Water Act when the area is
abandoned and has reverted to wetlands, as defined in paragraph
(3)(xvi) of this definition. Abandonment occurs when prior converted
cropland is not used for, or in support of, agricultural purposes at
least once in the immediately preceding five years. For the purposes of
the Clean Water Act, the EPA Administrator shall have the final
authority to determine whether prior converted cropland has been
abandoned.
 (x) Snowpack. The term snowpack means 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).
 (xi) Tidal waters and waters subject to the ebb and flow of the
tide. The terms tidal waters and waters subject to the ebb and flow of
the tide mean 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 and waters subject to the ebb and flow of the
tide 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.
 (xii) Tributary. The term tributary means a river, stream, or
similar naturally occurring surface water channel that contributes
surface water flow to a water identified in paragraph (1)(i) of this
definition in a typical year either directly or through one or more
waters identified in paragraph (1)(ii), (iii), or (iv) of this
definition. A tributary must be perennial or intermittent in a typical
year. The alteration or relocation of a tributary does not modify its
jurisdictional status as long as it continues to satisfy the flow
conditions of this definition. A tributary does not lose its
jurisdictional status if it contributes surface water flow to a
downstream jurisdictional water in a typical year through a channelized
non-jurisdictional surface water feature, through a subterranean river,
through a culvert, dam, tunnel, or similar artificial feature, or
through a debris pile, boulder field, or similar natural feature. The
term tributary includes a ditch that either relocates a tributary, is
constructed in a tributary, or is constructed in an adjacent wetland as
long as the ditch satisfies the flow conditions of this definition.
 (xiii) Typical year. The term typical year means 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.
 (xiv) Upland. The term upland means any land area that under normal
circumstances does not satisfy all three wetland factors (i.e.,
hydrology, hydrophytic vegetation, hydric soils) identified in
paragraph (3)(xvi) of this definition, and does not lie below the
ordinary high water mark or the high tide line of a jurisdictional
water.
 (xv) Waste treatment system. The term waste treatment system
includes all components, including lagoons and treatment ponds (such as
settling or cooling ponds), designed to either convey or retain,
concentrate, settle, reduce, or remove pollutants, either actively or
passively, from wastewater prior to discharge (or eliminating any such
discharge).
 (xvi) Wetlands. The term wetlands means 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.
PART 122--EPA ADMINISTERED PERMIT PROGRAMS: THE NATIONAL POLLUTANT
DISCHARGE ELIMINATION SYSTEM
0
12. The authority citation for part 122 continues to read as follows:
 Authority: The Clean Water Act, 33 U.S.C. 1251 et seq.
0
13. Section 122.2 is amended by:
0
a. Lifting the suspension of the last sentence of the definition of
``Waters of the United States'' published July 21, 1980 (45 FR 48620).
0
b. Revising the definition of ``Waters of the United States''.
0
c. Removing the definition of ``Wetlands''.
 The revision reads as follows:
Sec. 122.2 Definitions.
* * * * *
 Waters of the United States or waters of the U.S. means the term as
it is defined in Sec. 120.2 of this chapter.
* * * * *
PART 230--SECTION 404(b)(1) GUIDELINES FOR SPECIFICATION OF
DISPOSAL SITES FOR DREDGED OR FILL MATERIAL
0
14. The authority citation for part 230 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
15. Section 230.3 is amended by:
0
a. Removing paragraph (b) and reserved paragraphs (f), (g), (j), and
(l);
0
b. Redesignating paragraphs (c) through (e) as paragraphs (b) through
(d);
0
c. Redesignating paragraphs (h) and (i) as paragraphs (e) and (f)
0
d. Redesignating paragraph (k) as paragraph (g);
0
e. Redesignating paragraphs (m) through (q) as paragraphs (h) through
(l);
0
f. Redesignating paragraph (q-1) as paragraph (m);
0
g. Redesignating paragraph (r) as paragraph (n);
0
h. Redesignating paragraph (s) as paragraphs (o);
0
i. Revising newly designated paragraph (o); and
0
j. Removing paragraph (t).
 The revision reads as follows:
Sec. 230.3 Definitions.
* * * * *
 (o) Waters of the United States means the term as it is defined in
Sec. 120.2 of this chapter.
PART 232--404 PROGRAMS DEFINITIONS; EXEMPT ACTIVITIES NOT REQUIRING
404 PERMITS
0
16. The authority citation for part 232 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
17. Section 232.2 is amended by revising the definition of ``Waters of
the United States'' and removing the definition of ``Wetlands'' to read
as follows:
Sec. 232.2 Definitions.
* * * * *
 Waters of the United States means the term as it is defined in
Sec. 120.2 of this chapter.
[[Page 22342]]
PART 300--NATIONAL OIL AND HAZARDOUS SUBSTANCES POLLUTION
CONTINGENCY PLAN
0
18. The authority citation for part 300 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
19. Section 300.5 is amended by revising the definition of ``Navigable
waters'' to read as follows:
Sec. 300.5 Definitions.
* * * * *
 Navigable waters means the waters of the United States, including
the territorial seas, as defined in Sec. 120.2 of this chapter.
* * * * *
0
20. In appendix E to part 300, section 1.5 Definitions is amended by
revising the definition of ``Navigable waters'' to read as follows:
Appendix E to Part 300--Oil Spill Response
* * * * *
 1.5 Definitions. * * *
 Navigable waters means the waters of the United States,
including the territorial seas, as defined in Sec. 120.2 of this
chapter.
* * * * *
PART 302-- DESIGNATION, REPORTABLE QUANTITIES, AND NOTIFICATION
0
21. The authority citation for part 302 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
22. Section 302.3 is amended by revising the definition of ``Navigable
waters'' to read as follows:
Sec. 302.3 Definitions.
* * * * *
 Navigable waters means the waters of the United States, including
the territorial seas, as defined in Sec. 120.2 of this chapter.
* * * * *
PART 401-- GENERAL PROVISIONS
0
23. The authority citation for part 401 is revised to read as follows:
 Authority: 33 U.S.C. 1251 et seq.
0
24. Section 401.11 is amended by revising paragraph (l) to read as
follows:
Sec. 401.11 General definitions.
* * * * *
 (l) Navigable waters means ``waters of the United States, including
the territorial seas,'' as defined in Sec. 120.2 of this chapter.
[FR Doc. 2020-02500 Filed 4-20-20; 8:45 am]
 BILLING CODE 6560-50-P