Revised Definition of “Waters of the United States”

CourtArmy, Corps Of Engineers Department,Defense Department
Citation86 FR 69372
Published date07 December 2021
SectionProposed rules
Record Number2021-25601
Federal Register, Volume 86 Issue 232 (Tuesday, December 7, 2021)
[Federal Register Volume 86, Number 232 (Tuesday, December 7, 2021)]
                [Proposed Rules]
                [Pages 69372-69450]
                From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
                [FR Doc No: 2021-25601]
                [[Page 69371]]
                Vol. 86
                Tuesday,
                No. 232
                December 7, 2021
                Part IIDepartment of Defense----------------------------------------------------------------------- Department of the Army, Corps of Engineers-----------------------------------------------------------------------33 CFR Part 328Environmental Protection Agency-----------------------------------------------------------------------
                40 CFR Part 120Revised Definition of ``Waters of the United States''; Proposed Rule
                Federal Register / Vol. 86 , No. 232 / Tuesday, December 7, 2021 /
                Proposed Rules
                [[Page 69372]]
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                DEPARTMENT OF DEFENSE
                Department of the Army, Corps of Engineers
                33 CFR Part 328
                ENVIRONMENTAL PROTECTION AGENCY
                40 CFR Part 120
                [EPA-HQ-OW-2021-0602; FRL-6027.4-03-OW]
                Revised Definition of ``Waters of the United States''
                AGENCY: Department of the Army, Corps of Engineers, Department of
                Defense; and Environmental Protection Agency (EPA).
                ACTION: Proposed rule.
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                SUMMARY: The Environmental Protection Agency (EPA) and the Department
                of the Army (``the agencies'') are publishing for public comment a
                proposed rule defining the scope of waters protected under the Clean
                Water Act. This proposal is consistent with the Executive Order signed
                on January 20, 2021, on ``Protecting Public Health and the Environment
                and Restoring Science to Tackle the Climate Crisis,'' which directed
                the agencies to review the agencies' rule promulgated in 2020 defining
                ``waters of the United States.'' This proposed rule would meet the
                objective of the Clean Water Act and ensure critical protections for
                the nation's vital water resources, which support public health,
                environmental protection, agricultural activity, and economic growth
                across the United States.
                DATES: Comments must be received on or before February 7, 2022. Please
                refer to the SUPPLEMENTARY INFORMATION section for additional
                information on the public hearing.
                ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
                OW-2021-0602, by any of the following methods:
                 Federal eRulemaking Portal: https://www.regulations.gov/
                (our preferred method). Follow the online instructions for submitting
                comments.
                 Email: [email protected]. Include Docket ID No. EPA-HQ-OW-
                2021-0602 in the subject line of the message.
                 Instructions: All submissions received must include Docket ID No.
                EPA-HQ-OW-2021-0602. Comments received may be posted without change to
                https://www.regulations.gov/, including any personal information
                provided. For detailed instructions on sending comments and additional
                information on the rulemaking process, see the ``Public Participation''
                heading of the SUPPLEMENTARY INFORMATION section of this document. Out
                of an abundance of caution for members of the public and our staff, the
                EPA Docket Center and Reading Room are open to the public by
                appointment only to reduce the risk of transmitting COVID-19. Our
                Docket Center staff also continues to provide remote customer service
                via email, phone, and webform. Hand deliveries and couriers may be
                received by scheduled appointment only. For further information on EPA
                Docket Center services and the current status, please visit us online
                at https://www.epa.gov/dockets.
                FOR FURTHER INFORMATION CONTACT: Damaris Christensen, Oceans, Wetlands
                and Communities Division, Office of Water (4504-T), Environmental
                Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460;
                telephone number: (202) 564-2281; email address: [email protected], and
                Stacey Jensen, Office of the Assistant Secretary of the Army for Civil
                Works, Department of the Army, 108 Army Pentagon, Washington, DC 20310-
                0104; telephone number: (703) 459-6026; email address:
                [email protected].
                SUPPLEMENTARY INFORMATION:
                Table of Contents
                I. Executive Summary
                II. Public Participation
                 A. Written Comments
                 B. Virtual Public Hearings
                III. General Information
                 A. What action are the agencies taking?
                 B. What is the agencies' authority for taking this action?
                 C. What are the incremental costs and benefits of this action?
                IV. Background
                 A. Legal Background
                 B. The Agencies' Post-Rapanos Rules
                 C. Summary of Stakeholder Outreach
                V. Proposed Revised Definition
                 A. Basis for Proposed Rule
                 B. Concerns With Alternatives
                 C. Proposed Rule
                 D. Implementation of Proposed Rule
                 E. Publicly Available Jurisdictional Information and Permit Data
                 F. Placement of the Definition of ``Waters of the United
                States'' in the Code of Federal Regulations
                VI. Summary of Supporting Analyses
                VII. Statutory and Executive Order Reviews
                 A. Executive Order 12866: Regulatory Planning and Review;
                Executive Order 13563: Improving Regulation and Regulatory Review
                 B. Paperwork Reduction Act (PRA)
                 C. Regulatory Flexibility Act (RFA)
                 D. Unfunded Mandates Reform Act (UMRA)
                 E. Executive Order 13132: Federalism
                 F. Executive Order 13175: Consultation and Coordination With
                Indian Tribal Governments
                 G. Executive Order 13045: Protection of Children From
                Environmental Health and Safety Risks
                 H. Executive Order 13211: Actions Concerning Regulations That
                Significantly Affect Energy Supply, Distribution, or Use
                 I. National Technology Transfer and Advancement Act
                 J. Executive Order 12898: Federal Actions To Address
                Environmental Justice in Minority Populations and Low-Income
                Populations
                I. Executive Summary
                 Congress enacted the Federal Water Pollution Control Act Amendments
                of 1972, Public Law 92-500, 86 Stat. 816, as amended, 33 U.S.C. 1251 et
                seq. (Clean Water Act or Act) ``to restore and maintain the chemical,
                physical, and biological integrity of the Nation's waters.'' 33 U.S.C.
                1251(a). In doing so, Congress performed a ``total restructuring'' and
                ``complete rewriting'' of the existing statutory framework, seeking to
                better protect the quality of the nation's waters. City of Milwaukee v.
                Illinois, 451 U.S. 304, 317 (1981). Congress thus intended the 1972 Act
                to be a bold step forward in providing protections for the nation's
                waters.
                 Central to the framework and protections provided by the Clean
                Water Act is the term ``navigable waters,'' \1\ defined in the Act as
                ``the waters of the United States, including the territorial seas.'' 33
                U.S.C. 1362(7). This term establishes the extent of most federal
                programs to protect water quality under the Act--including, for
                example, water quality standards, impaired waters and total maximum
                daily loads, oil spill prevention, preparedness and response programs,
                state and tribal water quality certification programs, and dredged and
                fill programs--because such programs apply only to ``waters of the
                United States.''
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                 \1\ To avoid confusion between the term ``navigable waters'' as
                defined in the Clean Water Act and its implementing regulations, 33
                U.S.C. 1362(7); 33 CFR 328.3 (2014), and the traditional use of the
                term ``navigable waters'' to describe waters that are, have been, or
                could be used for interstate or foreign commerce, 33 CFR 328.3(a)(1)
                (2014), this preamble will refer to the latter as ``traditional
                navigable waters'' or waters that are ``navigable-in-fact.''
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                 As the Supreme Court presciently noted decades ago, defining this
                term requires the EPA and the U.S. Department of the Army (Army)
                (together, ``the agencies'') to ``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
                [[Page 69373]]
                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.''
                United States v. Riverside Bayview Homes, 474 U.S. 121, 132 (1985)
                (``Riverside Bayview'').\2\
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                 \2\ The Supreme Court has twice more addressed the issue of
                Clean Water Act jurisdiction over ``waters of the United States.''
                Solid Waste Agency of Northern Cook County v. U.S. Army Corps of
                Engineers, 531 U.S. 159 (2001) (``SWANCC''); Rapanos v. United
                States, 547 U.S. 715 (2006) (``Rapanos'').
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                 In the nearly five decades since the Clean Water Act was enacted,
                the agencies have undertaken the challenge of developing and
                implementing a durable definition of the term ``waters of the United
                States'' that draws the line on the Riverside Bayview ``continuum''
                consistent with the objective of the Act--to restore and maintain the
                chemical, physical, and biological integrity of the nation's waters--
                based on science, and refined over the years by extensive experience in
                implementing the definition in the field. In 2020, however, the
                agencies issued a rule, called the ``Navigable Waters Protection Rule''
                (NWPR), which substantially departed from prior rules defining ``waters
                of the United States.'' The earlier rules had been based on scientific
                concepts, implementation experience, and consideration of how the water
                quality implications of the definitions would advance the Clean Water
                Act's statutory objective. While the NWPR's interpretation of the
                statute and case law overlaps in some respects with those prior
                regulations--for example, its understanding that the statute authorizes
                the agencies to regulate waters beyond those that are navigable-in-
                fact--it departed from prior regulations by diminishing the appropriate
                role of science and Congress's objective in the Clean Water Act. The
                NWPR provided less protection and could have allowed far more impacts
                to the nation's waters than any rule that preceded it.
                 In response to President Joseph R. Biden Jr.'s Executive Order
                13990, 86 FR 7037 (January 25, 2021), which directed federal agencies
                to review certain regulations, EPA and the Army undertook a review of
                the NWPR. The agencies found that the NWPR did not appropriately
                consider the water quality impacts of its approach to defining ``waters
                of the United States,'' in contravention of Congress's objective in the
                Clean Water Act ``to restore and maintain the chemical, physical, and
                biological integrity of the Nation's waters,'' and that the rule's
                reduction in the scope of protected waters could have a potentially
                extensive and adverse impact on the nation's waters. The agencies'
                ongoing analyses of waters that fall outside of the Act's protections
                because of the NWPR support these findings.
                 Following a federal district court decision vacating the NWPR on
                August 30, 2021, the agencies halted implementation of the NWPR and
                began interpreting ``waters of the United States'' consistent with the
                pre-2015 regulatory regime.3 4 Though EPA and the U.S. Army
                Corps of Engineers (Corps) are not currently implementing the NWPR, the
                agencies are aware that further developments in litigation over the
                rule could bring the rule back into effect. For these reasons, among
                others discussed more fully below, the agencies have decided that
                prompt replacement of the NWPR through the administrative rulemaking
                process is vital.
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                 \3\ See Pascua Yaqui Tribe v. EPA, No. 20-00266 (D. Ariz. Aug.
                30, 2021); U.S. EPA, Current Implementation of Waters of the United
                States, https://www.epa.gov/wotus/current-implementation-waters-united-states.
                 \4\ The ``pre-2015 regulatory regime'' refers to the agencies'
                pre-2015 definition of ``waters of the United States,'' implemented
                consistent with relevant case law and longstanding practice, as
                informed by applicable guidance, training, and experience.
                ---------------------------------------------------------------------------
                 In order to ensure necessary federal protections for the nation's
                waters, the agencies are proposing to exercise their discretion under
                the statute to return generally to the familiar pre-2015 definition
                that has bounded the Act's protections for decades, has been codified
                multiple times, and has been implemented by every Administration for
                the last 35 years, from that of Ronald Reagan through Donald Trump,
                which re-promulgated the pre-2015 regulations. See In re EPA & Dep't of
                Def. Final Rule, 803 F.3d 804, 808 (6th Cir. 2015). The pre-2015
                regulations were largely in place for both agencies in 1986 and are
                thus commonly referred to as ``the 1986 regulations.'' \5\
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                 \5\ EPA and the Corps have separate regulations defining the
                statutory term ``waters of the United States,'' but their
                interpretations were substantially similar and remained largely
                unchanged between 1977 and 2015. See, e.g., 42 FR 37122, 37144 (July
                19, 1977); 44 FR 32854, 32901 (June 7, 1979). For convenience, the
                agencies in this preamble will generally cite the Corps'
                longstanding regulations and will refer to them as ``the 1986
                regulations,'' ``the pre-2015 regulations,'' or ``the regulations in
                place until 2015'' as inclusive of EPA's comparable regulations that
                were recodified in 1988 and of the exclusion for prior converted
                cropland both agencies added in 1993.
                ---------------------------------------------------------------------------
                 In this proposed rule the agencies are exercising their
                discretionary authority to interpret ``waters of the United States'' to
                mean the waters defined by the longstanding 1986 regulations, with
                amendments to certain parts of those rules to reflect the agencies'
                interpretation of the statutory limits on the scope of the ``waters of
                the United States'' and informed by Supreme Court case law. Thus, in
                the proposed rule, the agencies interpret the term ``waters of the
                United States'' to include: Traditional navigable waters, interstate
                waters, and the territorial seas, and their adjacent wetlands; most
                impoundments of ``waters of the United States''; tributaries to
                traditional navigable waters, interstate waters, the territorial seas,
                and impoundments that meet either the relatively permanent standard or
                the significant nexus standard; wetlands adjacent to impoundments and
                tributaries, that meet either the relatively permanent standard or the
                significant nexus standard; and ``other waters'' that meet either the
                relatively permanent standard or the significant nexus standard. The
                ``relatively permanent standard'' means waters that are relatively
                permanent, standing or continuously flowing and waters with a
                continuous surface connection to such waters. The ``significant nexus
                standard'' means waters that either alone or in combination with
                similarly situated waters in the region, significantly affect the
                chemical, physical, or biological integrity of traditional navigable
                waters, interstate waters, or the territorial seas (the ``foundational
                waters''). With these amendments to the 1986 regulations, the proposed
                rule is within the proper scope of the agencies' statutory authority
                and would restore and maintain the chemical, physical, and biological
                integrity of the nation's waters.
                 The proposed rule advances the Clean Water Act's statutory
                objective as it is based on the best available science concerning the
                functions provided by upstream tributaries, adjacent wetlands, and
                ``other waters'' to restore and maintain the water quality of
                downstream foundational waters. By contrast, the agencies conclude that
                the NWPR, which this proposed rule would replace, and which found
                jurisdiction primarily under the relatively permanent standard,
                established a test for jurisdiction that did not adequately address the
                impacts of degradation of upstream waters on downstream waters,
                including traditional navigable waters, and was therefore incompatible
                with the objective of the Clean Water Act. While
                [[Page 69374]]
                the ``more absolute position'' taken by the NWPR ``may be easier to
                administer,'' it has ``consequences that are inconsistent with major
                congressional objectives, as revealed by the statute's language,
                structure, and purposes.'' County of Maui, Hawaii v. Hawaii Wildlife
                Fund, 140 S. Ct. 1462, 1477 (2020).
                 In developing the proposed rule, the agencies also considered the
                statute as a whole, the scientific record, relevant Supreme Court case
                law, and the agencies' experience and expertise after more than 30
                years of implementing the 1986 regulations defining ``waters of the
                United States,'' including more than a decade of experience
                implementing those regulations consistent with the Supreme Court's
                decisions in Riverside Bayview, SWANCC, and Rapanos. The agencies'
                interpretation also reflects consideration of the statute as a whole,
                including section 101(b), which states that ``it is the policy of
                Congress to recognize, preserve, and protect the primary
                responsibilities and rights of States to prevent, reduce, and eliminate
                pollution, to plan the development and use (including restoration,
                preservation, and enhancement) of land and water resources.'' 33 U.S.C.
                1251(b). The proposed rule's limits appropriately draw the boundary of
                waters subject to federal protection by ensuring that where upstream
                waters significantly affect the integrity of waters and the federal
                interest is indisputable--the traditional navigable waters, interstate
                waters, and territorial seas--Clean Water Act programs would apply to
                ensure that those downstream waters are protected. And where they do
                not, the agencies would leave regulation to the states and tribes. The
                proposed rule's relatively permanent and significant nexus limitations
                are thus based on the agencies' conclusion that together, those
                standards are consistent with the statutory text, advance the objective
                of the Act, are supported by the scientific record and Supreme Court
                case law, and appropriately consider the policies of the Act. In
                addition, because the proposed rule reflects consideration of the
                agencies' experience and expertise, as well as updates in
                implementation tools and resources, it is familiar and implementable.
                 While there are case-specific determinations that would need to be
                made under this proposed rule, that was also true under the NWPR and
                many other regulatory regimes where agencies must balance competing
                factors. The agencies, moreover, believe that a return to the pre-2015
                definition would provide a known and familiar framework for co-
                regulators and stakeholders. In addition, the clarifications proposed
                here and the intervening advancements in implementation resources,
                tools, and scientific support (see section V.D.3.d of this preamble)
                would address some of the concerns raised in the past about timeliness
                and consistency of jurisdictional determinations under this regulatory
                regime.
                 Through this rulemaking process, the agencies will consider all
                public comments on the proposed rule including changes that improve
                clarity, implementability, and long-term durability of the definition.
                The agencies will also consider changes through a second rulemaking
                that they anticipate proposing in the future, which would build upon
                the foundation of this proposed rule.
                II. Public Participation
                A. Written Comments
                 Submit your comments, identified by Docket ID No. EPA-HQ-OW-2021-
                0602, at https://www.regulations.gov (our preferred method), or via the
                other methods identified in the ADDRESSES section. Once submitted,
                comments cannot be edited or removed from the docket. EPA and the Army
                may publish any comment received to the public docket. Do not submit to
                EPA's docket at https://www.regulations.gov any information you
                consider to be Confidential Business Information (CBI) or other
                information whose disclosure is restricted by statute. Multimedia
                submissions (audio, video, etc.) must be accompanied by a written
                comment. The written comment is considered the official comment and
                should include discussion of all points you wish to make. EPA and the
                Army will generally not consider comments or comment contents located
                outside of the primary submission (i.e., on the web, cloud, or other
                file sharing system). For additional submission methods, the full EPA
                public comment policy, information about CBI or multimedia submissions,
                and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
                 Due to public health concerns related to COVID-19, the EPA Docket
                Center and Reading Room are open to the public by appointment only. Our
                Docket Center staff also continue to provide remote customer service
                via email, phone, and webform. Hand deliveries or couriers will be
                received by scheduled appointment only. For further information and
                updates on EPA Docket Center services, please visit us online at
                https://www.epa.gov/dockets.
                 EPA and the Army continue to carefully monitor information from the
                Centers for Disease Control and Prevention (CDC), local area health
                departments, and our federal partners so that we can respond rapidly as
                conditions change regarding COVID-19.
                B. Virtual Public Hearings
                 Please note that because of current CDC recommendations, as well as
                state and local orders for social distancing to limit the spread of
                COVID-19, EPA and the Army cannot hold in-person public meetings at
                this time. The agencies are hosting virtual public hearings on
                Wednesday, January 12, 2022 from 10 a.m. to 1 p.m. Eastern Time; on
                Thursday, January 13, 2022 from 2 p.m. to 5 p.m. Eastern Time; and on
                Tuesday, January 18, 2022 from 5 p.m. to 8 p.m. Eastern Time.
                 EPA and the Army will begin pre-registering speakers for the
                hearing upon publication of this document in the Federal Register. To
                register to speak at a specific session of the virtual hearing, please
                use the online registration forms available at:
                 1. Wednesday, January 12, 2022--https://www.eventbrite.com/e/us-epa-and-department-of-the-army-wotus-public-hearing-tickets-211244667487.
                 2. Thursday, January 13, 2022--https://www.eventbrite.com/e/us-epa-and-department-of-the-army-wotus-public-hearing-tickets-211258017417.
                 3. Tuesday, January 18, 2022--https://www.eventbrite.com/e/us-epa-and-department-of-the-army-wotus-public-hearing-tickets-211274536827.
                 The last day to pre-register to speak at each session will be,
                respectively, Friday, January 7, 2022; Monday, January 10, 2022; and
                Thursday, January 13, 2022. A day before each scheduled session, EPA
                and the Army will post a general agenda for the hearing that will list
                pre-registered speakers in approximate order at https://www.epa.gov/wotus/public-outreach-and-stakeholder-engagement-activities. People may
                also register to listen to the public sessions at the registration
                links above.
                 To allow more time for speakers, the agencies may prerecord a video
                introduction and overview of the rule, which will be available on the
                EPA website above for viewing before the public hearings. EPA and the
                Army will make every effort to follow the schedule as closely as
                possible on the day of the hearing, but it is possible that the
                hearings will run either ahead of schedule or behind schedule.
                 Each commenter will have three (3) minutes to provide oral
                testimony. EPA and the Army encourage commenters to
                [[Page 69375]]
                provide the agencies with a copy of their oral testimony electronically
                by emailing it to [email protected]. EPA and the Army also recommend
                submitting the text of your oral comments as written comments to the
                rulemaking docket.
                 The agencies may ask clarifying questions during the oral
                presentations but will not respond to the presentations at that time.
                Written statements and supporting information submitted during the
                comment period will be considered with the same weight as oral comments
                and supporting information presented at the public hearing.
                 Please note that any updates made to any aspect of the hearing will
                be posted online at https://www.epa.gov/wotus/public-outreach-and-stakeholder-engagement-activities. While the agencies expect the
                hearing to go forward as set forth above, please monitor our website or
                contact [email protected] to determine if there are any updates. EPA and
                the Army do not intend to publish a document in the Federal Register
                announcing updates.
                 If you require the services of a translator or special
                accommodations such as audio description, please pre-register for the
                hearing with [email protected] and describe your needs a week in advance
                of each session--respectively, by Wednesday, January 5, 2022; Thursday,
                January 6, 2022; and Tuesday, January 11, 2022. EPA and the Army may
                not be able to arrange accommodations without advanced notice.
                III. General Information
                A. What action are the agencies taking?
                 In this action, the agencies are publishing a proposed rule
                defining ``waters of the United States'' in 33 CFR 328.3 and 40 CFR
                120.2.
                B. What is the agencies' authority for taking this action?
                 The authority for this action is the Federal Water Pollution
                Control Act, 33 U.S.C. 1251 et seq., including sections 301, 304, 311,
                401, 402, 404, and 501.
                C. What are the incremental costs and benefits of this action?
                 Because the agencies are not currently implementing the NWPR, the
                proposed rule would provide protections that are generally comparable
                to current practice; as such, the agencies find that there would be no
                appreciable cost or benefit difference. Potential costs and benefits
                would be incurred as a result of actions taken under existing Clean
                Water Act programs (i.e., sections 303, 311, 401, 402, and 404) that
                implement and follow this proposed rule. Entities currently are, and
                would continue to be, regulated under these programs that protect
                ``waters of the United States'' under the Clean Water Act.
                 The agencies prepared the Economic Analysis for the Proposed
                ``Revised Definition of `Waters of the United States' '' Rule
                (``Economic Analysis for the Proposed Rule''), available in the
                rulemaking docket, for informational purposes to analyze the potential
                costs and benefits associated with this proposed action. The agencies
                analyze the potential costs and benefits against two baselines: The
                current status quo and the vacated NWPR. The analysis is summarized in
                section VI of this preamble. The agencies' primary estimate is that the
                proposed rule would have zero impact.
                IV. Background
                A. Legal Background
                1. The Clean Water Act
                 Before passage of the Clean Water Act, the nation's waters were in
                ``serious trouble, thanks to years of neglect, ignorance, and public
                indifference.'' H.R. Rep. No. 92-911, at 753 (1972). Congress enacted
                the Federal Water Pollution Control Act Amendments of 1972, Public Law
                92-500, 86 Stat. 816, as amended, 33 U.S.C. 1251 et seq., with the
                objective ``to restore and maintain the chemical, physical and
                biological integrity of the Nation's waters.'' 33 U.S.C. 1251(a). The
                Act was intended to address longstanding concerns regarding the quality
                of the nation's waters and the Federal government's ability to respond
                to those concerns under existing law.
                 Prior to 1972, the Federal government's authority to control and
                redress pollution in the nation's waters largely fell to the Corps
                under the Rivers and Harbors Act of 1899. While much of that statute
                focused on restricting obstructions to navigation on the nation's major
                waterways, section 13 of the statute made it unlawful to discharge
                refuse ``into any navigable water of the United States, or into any
                tributary of any navigable water from which the same shall float or be
                washed into such navigable water.'' 33 U.S.C. 407. In 1948, Congress
                enacted the Federal Water Pollution Control Act of 1948, Public Law 80-
                845, 62 Stat. 1155 (June 30, 1948), to address interstate water
                pollution, and subsequently amended that statute in 1956, 1961, and
                1965. These early versions of the statute that eventually became known
                as the Clean Water Act encouraged the development of pollution
                abatement programs, required states to develop water quality standards,
                and authorized the Federal government to bring enforcement actions to
                abate water pollution. However, these authorities proved inadequate to
                address the decline in the quality of the nation's waters. See City of
                Milwaukee v. Illinois, 451 U.S. 304, 310 (1981).
                 As a result, in 1972, Congress performed ``a `total restructuring'
                and `complete rewriting' of the existing'' statutory framework. City of
                Milwaukee, 451 U.S. at 317 (quoting legislative history of 1972
                amendments). The Clean Water Act, which was passed as an amendment to
                the Federal Water Pollution Control Act, was described by its
                supporters as the first truly comprehensive federal water pollution
                legislation. The ``major purpose'' of the Clean Water Act was ``to
                establish a comprehensive long-range policy for the elimination of
                water pollution.'' S. Rep. No. 92-414, at 95 (1971), 2 Legislative
                History of the Water Pollution Control Act Amendments of 1972
                (Committee Print compiled for the Senate Committee on Public Works by
                the Library of Congress), Ser. No. 93-1, p. 1511 (1971) (emphasis
                added). ``No Congressman's remarks on the legislation were complete
                without reference to [its] `comprehensive' nature.'' City of Milwaukee,
                451 U.S. at 318. In passing the 1972 amendments, Congress ``intended to
                repudiate limits that had been placed on federal regulation by earlier
                water pollution control statutes and to exercise its powers under the
                Commerce Clause to regulate at least some waters that would not be
                deemed `navigable' under the classical understanding of that term.''
                United States v. Riverside Bayview Homes, 474 U.S. 121, 133 (1985)
                (``Riverside Bayview''); see also Int'l Paper Co. v. Ouellette, 479
                U.S. 481, 486 n.6 (1987).
                 One of the Clean Water Act's principal tools to protect the
                integrity of the nation's waters is section 301(a), which generally
                prohibits ``the discharge of any pollutant by any person'' without a
                permit or other authorization under the Act. The terms ``discharge of a
                pollutant'' and ``discharge of pollutants'' are defined broadly to
                include ``any addition of any pollutant to navigable waters from any
                point source.'' 33 U.S.C. 1362(12). And ``navigable waters'' means
                ``the waters of the United States, including the territorial seas.''
                Id. at 1362(7). Although Congress opted to carry over the term
                ``navigable waters'' from prior versions of the Federal Water Pollution
                Control Act, Congress broadened the definition
                [[Page 69376]]
                of ``navigable waters'' to encompass all ``waters of the United
                States.'' Id. Indeed, in finalizing the 1972 amendments, the conferees
                specifically deleted the word ``navigable'' from the definition of
                ``waters of the United States'' that had originally appeared in the
                House version of the Act. S. Conf. Rep. No. 92-1236, at 144 (1972).
                Further, the Senate Report stated that ``navigable waters'' means ``the
                navigable waters of the United States, portions thereof, tributaries
                thereof, and includes the Territorial Seas and the Great Lakes.'' S.
                Rep. No. 92-414, at 77 (1971), as reprinted in 1972 U.S.C.C.A.N. 3668,
                3742-43 (emphasis added). The Senate Report accompanying the 1972 Act
                also explained that ``[w]ater moves in hydrologic cycles and it is
                essential that the discharge of pollutants be controlled at the
                source.'' Id.
                 The definition of ``waters of the United States'' affects most
                Clean Water Act programs--including water quality standards, impaired
                waters and total maximum daily loads, oil spill prevention,
                preparedness and response programs, the state and tribal water quality
                certification programs, National Pollutant Discharge Elimination System
                (NPDES) programs, and dredge and fill programs--because such programs
                apply only to ``waters of the United States.'' Some Clean Water Act
                programs are implemented by the Federal government, and others are
                implemented by state or tribal governments where the statute provides a
                direct grant of authority to the state or authorized tribe or provides
                an option for the state or authorized tribe to take on those programs.
                States and tribes may additionally implement, establish, or modify
                their own programs under state or tribal law to manage and regulate
                waters independent of the Clean Water Act.
                 Under Clean Water Act section 303(d) and EPA's implementing
                regulations, states are required to assemble and evaluate all existing
                and readily available water quality-related data and information and to
                submit to EPA every two years a list of impaired waters that require
                total maximum daily loads (TMDLs). For waters identified on a 303(d)
                list, states establish TMDLs for all pollutants preventing or expected
                to prevent attainment of water quality standards. Section 303(d)
                applies to ``waters of the United States'' and ``non-jurisdictional''
                waterbodies are not required to be assessed or otherwise identified as
                impaired; TMDL restoration plans likewise apply to ``waters of the
                United States.''
                 Clean Water Act section 311 and the Oil Pollution Act (OPA) of 1990
                authorize the Oil Spill Liability Trust Fund (OSLTF) to reimburse costs
                of assessing and responding to oil spills to ``waters of the United
                States'' or adjoining shorelines. The OSLTF allows an immediate
                response to a spill, including containment, countermeasures, cleanup,
                and disposal activities. The OSLTF is not available to reimburse costs
                incurred by states or tribes to clean up spills and costs related to
                business and citizen impacts (e.g., lost wages and damages) for spills
                affecting waters not subject to Clean Water Act jurisdiction. EPA also
                lacks authority to take enforcement actions based on spills solely
                affecting waters not subject to Clean Water Act jurisdiction.
                 The scope of facilities required to prepare oil spill prevention
                and response plans is also affected by the definition of ``waters of
                the United States.'' EPA-regulated oil storage facilities with storage
                capacities greater than 1,320 gallons (except farms) that have a
                reasonable expectation of an oil discharge to ``waters of the United
                States'' or adjoining shorelines are required to prepare and implement
                spill prevention plans. High-risk oil storage facilities that meet
                certain higher storage thresholds and related harm factors are required
                to prepare and submit oil spill preparedness plans to EPA for review.
                The U.S. Coast Guard and Department of Transportation also require oil
                spill response plans under their respective authorities. However, Clean
                Water Act section 311 spill prevention and preparedness plan
                requirements do not apply to a facility if there is no reasonable
                expectation that an oil discharge from a facility could reach a
                jurisdictional water or adjoining shoreline.
                 Clean Water Act section 401 provides that a Federal agency cannot
                issue a permit or license for an activity that may result in a
                discharge to ``waters of the United States'' until the state or tribe
                where the discharge would originate has granted or waived water quality
                certification. As a result, section 401 certification provides states
                and authorized tribes an opportunity to address the proposed aquatic
                resource impacts of federally-issued permits and licenses. The
                definition of ``waters of the United States'' affects where federal
                permits are required and thus where section 401 certification applies.
                 Under section 402 of the Clean Water Act, a National Pollutant
                Discharge Elimination System (NPDES) permit is required where a point
                source discharges a pollutant to a ``water of the United States.''
                 The Clean Water Act section 404 permitting program addresses the
                discharge of dredged or fill material from a point source into ``waters
                of the United States,'' unless the activity is exempt from Clean Water
                Act section 404 regulation (e.g., certain farming, ranching, and
                forestry activities). Section 404 requires a permit before dredged or
                fill material may be discharged to ``waters of the United States.''
                Where Clean Water Act jurisdiction does not apply, no section 404
                permits are required for dredged or fill activities in those waters or
                features.
                 States and tribes play a vital role in the implementation and
                enforcement of these and other Clean Water Act programs. Section 101(b)
                of the Act established that ``it is the policy of Congress to
                recognize, preserve and protect the primary responsibilities and rights
                of States to prevent, reduce and eliminate pollution, to plan the
                development and use (including restoration, preservation, and
                enhancement) of land and water resources.'' 33 U.S.C. 1251(b). All
                states and 74 tribes have authority to implement section 401 water
                quality certification programs. Currently 47 states and one territory
                have authority to administer all or portions of the section 402 NPDES
                program for ``waters of the United States.'' All states and 46 tribes
                have established water quality standards pursuant to section 303 of the
                Act, which form a legal basis for limitations on discharges of
                pollutants to ``waters of the United States.''
                 Moreover, consistent with the Clean Water Act, states and tribes
                retain authority to implement their own programs to protect the waters
                in their jurisdiction more broadly and more stringently than the
                Federal government. Under section 510 of the Clean Water Act, unless
                expressly stated, nothing in the Clean Water Act precludes or denies
                the right of any state or tribe to establish more protective standards
                or limits than the Clean Water Act.\6\ Many states and tribes, for
                example, regulate groundwater, and some others protect wetlands that
                are vital to their environment and economic
                [[Page 69377]]
                well-being but which may be outside the scope of the Clean Water Act.
                ---------------------------------------------------------------------------
                 \6\ Congress has provided for eligible tribes to administer
                Clean Water Act programs over their reservations and expressed a
                preference for tribal regulation of surface water quality on
                reservations to ensure compliance with the goals of the statute. See
                33 U.S.C. 1377; 56 FR 64876, 64878-79 (December 12, 1991). In
                addition, tribes may establish more protective standards or limits
                under tribal law that may be more stringent than the federal Clean
                Water Act. Where appropriate, references to states in this document
                may also include eligible tribes.
                ---------------------------------------------------------------------------
                 In 1977, Congress considered and rejected a legislative proposal
                that would have redefined and limited the waters subject to the Corps'
                permitting authority under section 404 of the Clean Water Act to only
                navigable-in-fact waters and their adjacent wetlands. In 1975, the
                Corps had extended the scope of ``waters of the United States'' to
                encompass, in a phased approach, non-navigable tributaries, wetlands
                adjacent to primary navigable waters, intermittent rivers, streams,
                tributaries, and certain other categories of waters. 40 FR 31325-31326
                (1975). In reaction to that broadened definition, Congress considered a
                proposal to limit the geographic reach of section 404, but it was
                defeated in the Senate and eliminated by the Conference Committee. H.R.
                Conf. Rep. No. 95-830, at 97-105 (1977). As the Supreme Court explained
                in Riverside Bayview, ``efforts to narrow the definition of `waters'
                were abandoned; the legislation as ultimately passed, in the words of
                Senator Baker, `retain[ed] the comprehensive jurisdiction over the
                Nation's waters exercised in the 1972 Federal Water Pollution Control
                Act. ' '' 474 U.S. at 136-137; see also 123 Cong. Rec. 26718 (1977)
                (remarks of Senator Baker: ``Continuation of the comprehensive coverage
                of this program is essential for the protection of the aquatic
                environment. The once seemingly separable types of aquatic systems are,
                we now know, interrelated and interdependent. We cannot expect to
                preserve the remaining qualities of our water resources without
                providing appropriate protection for the entire resource.'').
                 Rather than alter the geographic reach of section 404 in 1977,
                Congress instead amended the statute by exempting certain activities--
                for example, certain agricultural and silvicultural activities--from
                the permit requirements of section 404. See 33 U.S.C. 1344(f). The
                amendments also authorized the use of general permits to streamline the
                permitting process. See id. at 1344(e). Finally, the 1977 Act
                established for the first time a mechanism by which a state, rather
                than the Corps, could assume responsibility for implementing the
                section 404 permitting program, but only for waters ``other than''
                traditional navigable waters and their adjacent wetlands. Id. at
                1344(g)(1). Three states have since assumed the section 404 program.
                 The fact that a resource is a ``water of the United States'' does
                not mean that activities such as farming, construction, infrastructure
                development, or resource extraction, cannot occur in or near the
                resource at hand. The Clean Water Act exempts a number of activities
                from permitting or from the definition of ``point source,'' including
                agricultural storm water and irrigation return flows. See id. at
                1342(l)(2), 1362(14). As discussed above, since 1977 the Clean Water
                Act in section 404(f) has exempted many normal farming activities from
                the section 404 permitting requirement, including seeding, harvesting,
                cultivating, planting, and soil and water conservation practices, among
                other activities. Id. at 1344(f). The scope of ``waters of the United
                States'' does not affect these statutory exemptions.
                 In addition, permits are routinely issued under sections 402 and
                404 of the Clean Water Act. The permitting authority, which is most
                often a state agency for the section 402 NPDES program and the Corps in
                the context of section 404, generally works with permit seekers to
                ensure that activities can occur without harming the integrity of the
                nation's waters.
                 Effluent limitations serve as the primary mechanism in NPDES
                permits for controlling discharges of pollutants to receiving waters,
                and include technology-based effluent limitations and water quality-
                based effluent limitations. These limits, which are typically numeric,
                generally specify an acceptable level of a pollutant or pollutant
                parameter in a discharge (for example, a certain level of bacteria).
                The permittee may choose which technologies to use to achieve that
                level. Some permits contain certain ``best management practices''
                (BMPs) which are actions or procedures to prevent or reduce the
                discharge of pollution to ``waters of the United States'' (for example,
                stormwater control measures for construction activities).
                 In issuing section 404 permits, the Corps or authorized state works
                with the applicant to avoid, minimize, or compensate for any
                unavoidable impacts to ``waters of the United States.'' Permit
                applicants show that steps have been taken to avoid impacts to
                wetlands, streams, and other aquatic resources; that potential impacts
                have been minimized; and that compensatory mitigation will be provided
                for all remaining unavoidable impacts. For most discharges that will
                have only minimal adverse effects, a general permit (e.g., a
                ``nationwide'' permit) may be suitable. General permits are issued on a
                nationwide, regional, or state basis for particular categories of
                activities. While some general permits require the applicant to submit
                a pre-construction notification to the Corps, others allow the
                applicant to proceed with no formal notification. The general permit
                process eliminates individual review and allows certain activities to
                proceed with little or no delay, provided that the general or specific
                conditions for the general permit are met. For example, minor road
                construction activities, utility line backfill, and minor discharges
                for maintenance are activities in ``waters of the United States'' that
                can be considered for a general permit. States and tribes also have a
                role in section 404 decisions, through state program general permits,
                water quality certification, or program assumption.
                 Under any regulation defining ``waters of the United States,''
                property owners may obtain from the Corps jurisdictional determinations
                whether waters on their property are subject to the Clean Water Act.
                The Corps' regulations provide that a jurisdictional determination
                consists of ``a written Corps determination that a wetland and/or
                waterbody is subject to regulatory jurisdiction under Section 404 of
                the Clean Water Act (33 U.S.C. 1344) or a written determination that a
                waterbody is subject to regulatory jurisdiction under Section 9 or 10
                of the Rivers and Harbors Act of 1899 (33 U.S.C. 401 et seq.).'' See 33
                CFR 331.2. These jurisdictional determinations can be obtained at no
                charge to the property owners. See 33 CFR 325.1 (omitting mention of
                fees for jurisdictional determinations) and Regulatory Guidance Letter
                16-01 (2016) (stating that such determinations are issued as a ``public
                service'').
                2. The 1986 Regulations Defining ``Waters of the United States''
                 In 1973, EPA published regulations defining ``navigable waters''
                broadly to include traditional navigable waters; tributaries of
                traditional navigable waters; interstate waters; and intrastate lakes,
                rivers, and streams used in interstate commerce. 38 FR 13528, 13528-29
                (May 22, 1973). The Corps published regulations in 1974 defining the
                term ``navigable waters'' to mean ``those waters of the United States
                which are subject to the ebb and flow of the tide, and/or are
                presently, or have been in the past, or may be in the future
                susceptible for use for purposes of interstate or foreign commerce.''
                39 FR 12115, 12119 (April 3, 1974); 33 CFR 209.120(d)(1) (1974); see
                also 33 CFR 209.260(e)(1) (1974) (explaining that ``[i]t is the water
                body's capability of use by the public for purposes of transportation
                or commerce which is the determinative factor'').
                 Several federal courts then held that the Corps had given ``waters
                of the
                [[Page 69378]]
                United States'' an unduly restrictive reading in its regulations
                implementing Clean Water Act section 404. See, e.g., United States v.
                Holland, 373 F. Supp. 665, 670-676 (M.D. Fla. 1974). EPA and the House
                Committee on Government Operations agreed with the decision in
                Holland.\7\ In Natural Resources Defense Council, Inc. v. Callaway, 392
                F. Supp. 685, 686 (D.D.C. 1975) (``Callaway''), the court held that in
                the Clean Water Act, Congress had ``asserted federal jurisdiction over
                the nation's waters to the maximum extent permissible under the
                Commerce Clause of the Constitution. Accordingly, as used in the
                [Federal] Water [Pollution Control] Act, the term [`navigable waters']
                is not limited to the traditional tests of navigability.'' The court
                ordered the Corps to publish new regulations ``clearly recognizing the
                full regulatory mandate of the [Federal] Water [Pollution Control]
                Act.'' Id.
                ---------------------------------------------------------------------------
                 \7\ EPA expressed the view that ``the Holland decision provides
                a necessary step for the preservation of our limited wetland
                resources,'' and that ``the [Holland] court properly interpreted the
                jurisdiction granted under the [Clean Water Act] and Congressional
                power to make such a grant.'' See section 404 of the Federal Water
                Pollution Control Act Amendments of 1972: Hearings Before the Senate
                Comm. on Pub. Works, 94th Cong., 2d Sess. 349 (1976) (letter dated
                June 19, 1974, from Russell E. Train, Administrator of EPA, to Lt.
                Gen. W.C. Gribble, Jr., Chief of Corps of Engineers). Shortly
                thereafter, the House Committee on Government Operations discussed
                the disagreement between the two agencies (as reflected in EPA's
                June 19 letter) and concluded that the Corps should adopt the
                broader view of the term ``waters of the United States'' taken by
                EPA and by the court in Holland. See H.R. Rep. No. 93-1396, at 23-27
                (1974). The Committee urged the Corps to adopt a new definition that
                ``complies with the congressional mandate that this term be given
                the broadest possible constitutional interpretation.'' Id. at 27
                (internal quotation marks omitted).
                ---------------------------------------------------------------------------
                 In response to the district court's order in Callaway, the Corps
                promulgated interim final regulations providing for a phased-in
                expansion of its section 404 jurisdiction. 40 FR 31320 (July 25, 1975);
                see 33 CFR 209.120(d)(2) and (e)(2) (1976). The interim regulations
                revised the definition of ``waters of the United States'' to include,
                inter alia, waters (sometimes referred to as ``isolated waters'') that
                are not connected by surface water or adjacent to traditional navigable
                waters. 33 CFR 209.120(d)(2)(i) (1976).\8\ On July 19, 1977, the Corps
                published its final regulations, in which it revised the 1975 interim
                regulations to clarify many of the definitional terms. 42 FR 37122
                (July 19, 1977). The 1977 final regulations defined the term ``waters
                of the United States'' to include, inter alia, ``isolated wetlands and
                lakes, intermittent streams, prairie potholes, and other waters that
                are not part of a tributary system to interstate waters or to navigable
                waters of the United States, the degradation or destruction of which
                could affect interstate commerce.'' 33 CFR 323.2(a)(5) (1978); see also
                40 CFR 122.3 (1979).\9\
                ---------------------------------------------------------------------------
                 \8\ Phase I, which was immediately effective, included coastal
                waters and traditional inland navigable waters and their adjacent
                wetlands. 40 FR 31321, 31324, 31326 (July 25, 1975). Phase II, which
                took effect on July 1, 1976, extended the Corps' jurisdiction to
                lakes and certain tributaries of Phase I waters, as well as wetlands
                adjacent to the lakes and certain tributaries. Id. Phase III, which
                took effect on July 1, 1977, extended the Corps' jurisdiction to all
                remaining areas encompassed by the regulations, including
                ``intermittent rivers, streams, tributaries, and perched wetlands
                that are not contiguous or adjacent to navigable waters.'' Id. at
                31325; see also 42 FR 37124 (July 19, 1977) (describing the three
                phases).
                 \9\ An explanatory footnote published in the Code of Federal
                Regulations stated that ``[p]aragraph (a)(5) incorporates all other
                waters of the United States that could be regulated under the
                Federal government's Constitutional powers to regulate and protect
                interstate commerce.'' 33 CFR 323.2(a)(5), at 616 n.2 (1978).
                ---------------------------------------------------------------------------
                 In 1986, the Corps consolidated and recodified its regulatory
                provisions defining ``waters of the United States'' for purposes of
                implementing the section 404 program. See 51 FR 41216-17 (November 13,
                1986). These regulations reflected the interpretation of both agencies.
                While EPA and the Corps also have separate regulations defining the
                statutory term ``waters of the United States,'' their interpretations,
                reflected in the 1986 regulations, have been identical and remained
                largely unchanged from 1977 to 2015. See 42 FR 37122, 37124, 37127
                (July 19, 1977).\10\ EPA's comparable regulations were recodified in
                1988 (53 FR 20764, June 6, 1988), and both agencies added an exclusion
                for prior converted cropland in 1993 (58 FR 45008, 45031, August 25,
                1993). For convenience, the agencies in this preamble will generally
                cite the Corps' longstanding regulations and will refer to ``the 1986
                regulations'' as inclusive of EPA's comparable regulations and the 1993
                addition of the exclusion for prior converted cropland.
                ---------------------------------------------------------------------------
                 \10\ Multiple provisions in the Code of Federal Regulations
                contained the definition of the phrases ``waters of the United
                States'' and ``navigable waters'' for purposes of implementing the
                Clean Water Act, 33 U.S.C. 1362(7), and other water pollution
                protection statutes such as the Oil Pollution Act, 33 U.S.C.
                2701(21). Some EPA definitions were added after 1986, but each
                conformed to the 1986 regulations except for variations in the waste
                treatment system exclusion. See, e.g., 55 FR 8666 (March 8, 1990);
                73 FR 71941 (November 26, 2008).
                ---------------------------------------------------------------------------
                 The 1986 regulations define ``waters of the United States'' as
                follows (33 CFR 328.3 (2014)) \11\:
                ---------------------------------------------------------------------------
                 \11\ There are some variations in the waste treatment system
                exclusion across EPA's regulations defining ``waters of the United
                States.'' The placement of the waste treatment system and prior
                converted cropland exclusions also varies in EPA's regulations.
                ---------------------------------------------------------------------------
                 The term waters of the United States means:
                 1. All waters which are currently used, or were used in the past,
                or may be susceptible to use in interstate or foreign commerce,
                including all waters which are subject to the ebb and flow of the tide;
                 2. All interstate waters including interstate wetlands;
                 3. All other waters such as intrastate lakes, rivers, streams
                (including intermittent streams), mudflats, sandflats, wetlands,
                sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds,
                the use, degradation or destruction of which could affect interstate or
                foreign commerce including any such waters:
                 a. Which are or could be used by interstate or foreign travelers
                for recreational or other purposes; or
                 b. From which fish or shellfish are or could be taken and sold in
                interstate or foreign commerce; or
                 c. Which are used or could be used for industrial purposes by
                industries in interstate commerce;
                 4. All impoundments of waters otherwise defined as waters of the
                United States under this definition;
                 5. Tributaries of waters identified in paragraphs (a)(1) through
                (4) of this section;
                 6. The territorial seas;
                 7. Wetlands adjacent to waters (other than waters that are
                themselves wetlands) identified in paragraphs (a)(1) through (6) of
                this section.
                 8. Waters of the United States do not include prior converted
                cropland. Notwithstanding the determination of an area's status as
                prior converted cropland by any other federal agency, for the purposes
                of the Clean Water Act, the final authority regarding Clean Water Act
                jurisdiction remains with EPA. Waste treatment systems, including
                treatment ponds or lagoons designed to meet the requirements of Clean
                Water Act (other than cooling ponds as defined in 40 CFR 423.11(m)
                which also meet the criteria of this definition) are not waters of the
                United States.
                 Note that these categories in the 1986 regulations may be referred
                to by this numbering system (for example, (a)(1) through (a)(8) waters)
                throughout this preamble. See sections I.C.3 and I.C.4 of the Economic
                Analysis for the Proposed Rule for a comparison of regulatory
                categories between the NWPR and this proposed rule.
                3. U.S. Supreme Court Decisions
                 The U.S. Supreme Court first addressed the scope of ``waters of the
                United States'' protected by the Clean
                [[Page 69379]]
                Water Act in United States v. Riverside Bayview Homes, 474 U.S. 121
                (1985) (``Riverside Bayview''), which involved wetlands adjacent to a
                traditional navigable water in Michigan. In a unanimous opinion, the
                Court deferred to the Corps' judgment that adjacent wetlands are
                ``inseparably bound up with the `waters' of the United States,'' thus
                concluding that ``adjacent wetlands may be defined as waters under the
                Act.'' Riverside Bayview, 474 U.S. at 134, 139. The Court observed that
                the broad objective of the Clean Water Act to restore the integrity of
                the nation's waters ``incorporated a broad, systemic view of the goal
                of maintaining and improving water quality . . . . Protection of
                aquatic ecosystems, Congress recognized, demanded broad federal
                authority to control pollution, for `[w]ater moves in hydrologic cycles
                and it is essential that discharge of pollutants be controlled at the
                source.' '' Id. at 132-33 (citing S. Rep. 92-414). The Court then
                stated: ``In keeping with these views, Congress chose to define the
                waters covered by the Act broadly. Although the Act prohibits
                discharges into `navigable waters,' see CWA [sections] 301(a), 404(a),
                502(12), 33 U.S.C. [sections] 1311(a), 1344(a), 1362(12), the Act's
                definition of `navigable waters' as `the waters of the United States'
                makes it clear that the term `navigable' as used in the Act is of
                limited import.'' Id. at 133.
                 The Court also recognized that ``[i]n determining the limits of its
                power to regulate discharges under the Act, the Corps must necessarily
                choose some point at which water ends and land begins. Our common
                experience tells us that this is often no easy task: The transition
                from water to solid ground is not necessarily or even typically an
                abrupt one. Rather, between open waters and dry land may lie shallows,
                marshes, mudflats, swamps, bogs--in short, a huge array of areas that
                are not wholly aquatic but nevertheless fall far short of being dry
                land. Where on this continuum to find the limit of `waters' is far from
                obvious.'' Id. at 132. The Court then deferred to the agencies'
                interpretation: ``In view of the breadth of federal regulatory
                authority contemplated by the Act itself and the inherent difficulties
                of defining precise bounds to regulable waters, the Corps' ecological
                judgment about the relationship between waters and their adjacent
                wetlands provides an adequate basis for a legal judgment that adjacent
                wetlands may be defined as waters under the Act.'' Id. at 134.
                 The Court went on to note that to achieve the goal of preserving
                and improving adjacent wetlands that have significant ecological and
                hydrological impacts on traditional navigable waters, it was
                appropriate for the Corps to regulate all adjacent wetlands, even
                though some might not have any impacts on traditional navigable waters.
                Id. at 135 n.9. Indeed, the Court acknowledged that some adjacent
                wetlands might not have significant hydrological and biological
                connections with navigable waters, but concluded that the Corps'
                regulation was valid in part because such connections exist in the
                majority of cases. Id.
                 The Court deferred to the Corps' definition of ``adjacent'': ``The
                term adjacent means bordering, contiguous, or neighboring. Wetlands
                separated from other waters of the United States by man-made dikes or
                barriers, natural river berms, beach dunes and the like are `adjacent
                wetlands.' '' The Court expressly reserved the question of whether the
                Act applies to ``wetlands that are not adjacent to open waters.'' Id.
                at 131 n.8.
                 The Supreme Court again addressed the issue of Clean Water Act
                jurisdiction over ``waters of the United States'' in Solid Waste Agency
                of Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159
                (2001) (``SWANCC''). In SWANCC, the Court (in a 5-4 opinion) held that
                the use of ``isolated'' non-navigable intrastate ponds by migratory
                birds was not by itself a sufficient basis for the exercise of federal
                authority under the Clean Water Act. The Court noted that in Riverside
                Bayview it had ``found that Congress' concern for the protection of
                water quality and aquatic ecosystems indicated its intent to regulate
                wetlands `inseparably bound up with the ``waters'' of the United
                States' '' and that ``[i]t was the significant nexus between the
                wetlands and `navigable waters' that informed [the Court's] reading of
                the Clean Water Act'' in that case. Id. at 167.
                 While recognizing that in Riverside Bayview it had found the term
                ``navigable'' to be of limited import, the Court in SWANCC noted that
                the term ``navigable'' could not be read entirely out of the Act. Id.
                at 172. The Court stated: ``We said in Riverside Bayview Homes that the
                word `navigable' in the statute was of `limited import' and went on to
                hold that [section] 404(a) extended to non-navigable wetlands adjacent
                to open waters. But it is one thing to give a word limited effect and
                quite another to give it no effect whatever. The term `navigable' has
                at least the import of showing us what Congress had in mind as its
                authority for enacting the CWA: its traditional jurisdiction over
                waters that were or had been navigable in fact or which could
                reasonably be so made.'' Id. at 172 (internal citations omitted).
                 The Court found that the exercise of Clean Water Act regulatory
                authority over discharges into the ponds, on the grounds that their use
                by migratory birds is within the power of Congress to regulate
                activities that in the aggregate have a substantial effect on
                interstate commerce, raised questions. Id. at 173. The Court explained
                that ``[w]here an administrative interpretation of a statute invokes
                the outer limits of Congress' power, we expect a clear indication that
                Congress intended that result,'' id. at 172, and that this is
                particularly true ``where the administrative interpretation alters the
                federal-state framework by permitting federal encroachment upon a
                traditional state power,'' id. at 173 (citing United States v. Bass,
                404 U.S. 336, 349 (1971)). The Court thus construed the Clean Water Act
                to avoid the constitutional questions related to the scope of federal
                authority authorized therein. Id. at 174.
                 Five years after SWANCC, the Court again addressed the Clean Water
                Act term ``waters of the United States'' in Rapanos v. United States,
                547 U.S. 715 (2006) (``Rapanos''). Rapanos involved two consolidated
                cases in which the Act had been applied to wetlands adjacent to non-
                navigable tributaries of 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. Id. at 731 ((Scalia, J., plurality opinion) (``We have twice
                stated that the meaning of `navigable waters' in the Act is broader
                than the traditional understanding of that term, SWANCC, 531 U.S. at
                167, 121 S. Ct. 675, 148 L. Ed. 2d 576; Riverside Bayview, 474 U.S. at
                133, 106 S. Ct. 455, 88 L. Ed. 2d 419.'')).
                 A four-Justice plurality in Rapanos interpreted the term ``waters
                of the United States'' as covering ``relatively permanent, standing or
                continuously flowing bodies of water,'' id. at 739, that are connected
                to traditional navigable waters, id. at 742, as well as wetlands with a
                ``continuous surface connection'' to such water bodies, id. (Scalia,
                J., plurality opinion). The Rapanos plurality noted that its reference
                to ``relatively permanent'' waters did ``not necessarily exclude
                streams, rivers, or lakes that might dry up in extraordinary
                circumstances, such as drought,'' or ``seasonal rivers, which contain
                continuous flow during some months of the year but no flow during dry
                months.'' Id. at 732 n.5 (emphasis in original).
                 Justice Kennedy's concurring opinion took a different approach that
                was based
                [[Page 69380]]
                in the Court's SWANCC opinion. Justice Kennedy concluded that ``to
                constitute `navigable waters' under the Act, a water or wetland must
                possess a `significant nexus' to waters that are or were navigable in
                fact or that could reasonably be so made.'' Id. at 759 (citing SWANCC,
                531 U.S. at 167, 172). He concluded that wetlands possess the requisite
                significant nexus if the wetlands ``either alone or in combination with
                similarly situated [wet]lands in the region, significantly affect the
                chemical, physical, and biological integrity of other covered waters
                more readily understood as `navigable.' '' Id. at 780. Justice
                Kennedy's opinion notes that to be jurisdictional, such a relationship
                with traditional navigable waters must be more than ``speculative or
                insubstantial.'' Id.
                 The four dissenting Justices in Rapanos, who would have affirmed
                the court of appeals' application of the agencies' regulation to find
                jurisdiction over the waters at issue, also concluded that the term
                ``waters of the United States'' encompasses, inter alia, all
                tributaries and wetlands that satisfy ``either the plurality's
                [standard] or Justice Kennedy's.'' Id. at 810 & n.14 (Stevens, J.,
                dissenting). The four dissenting Justices stated: ``The Army Corps has
                determined that wetlands adjacent to tributaries of traditionally
                navigable waters preserve the quality of our Nation's waters by, among
                other things, providing habitat for aquatic animals, keeping excessive
                sediment and toxic pollutants out of adjacent waters, and reducing
                downstream flooding by absorbing water at times of high flow. The
                Corps' resulting decision to treat these wetlands as encompassed within
                the term `waters of the United States' is a quintessential example of
                the Executive's reasonable interpretation of a statutory provision.''
                Id. at 788 (citation omitted).
                 In addition to joining the plurality's opinion, Chief Justice
                Roberts issued his own concurring opinion noting that the agencies
                ``are afforded generous leeway by the courts in interpreting the
                statute they are entrusted to administer,'' and the agencies thus have
                ``plenty of room to operate in developing some notion of an outer bound
                to the reach of their authority'' under the Clean Water Act. Id. at
                758.
                 Neither the plurality nor the concurring opinions in Rapanos
                invalidated any of the regulatory provisions defining ``waters of the
                United States.''
                4. Post-Rapanos Appellate Court Decisions
                 The earliest post-Rapanos decisions by the United States Courts of
                Appeals focused on which standard to apply in interpreting the scope of
                ``waters of the United States''--the plurality's or Justice Kennedy's.
                Chief Justice Roberts anticipated this question and cited Marks v.
                United States, 430 U.S. 188 (1977) in his concurring opinion to Rapanos
                as applicable precedent. Marks v. United States provides that ``[w]hen
                a fragmented Court decides a case and no single rationale explaining
                the result enjoys the assent of five Justices, the holding of the Court
                may be viewed as the position taken by those Members who concurred in
                the judgments on the narrowest grounds.'' The dissenting Justices in
                Rapanos also spoke to future application of the divided decision. While
                Justice Stevens stated that he assumed Justice Kennedy's significant
                nexus standard would apply in most instances, the dissenting Justices
                noted that they would find the Clean Water Act extended to waters
                meeting either the relatively permanent standard articulated by Justice
                Scalia or the significant nexus standard described by Justice Kennedy.
                Rapanos, 547 U.S. at 810 & n.14 (Stevens, J., dissenting).
                 Since Rapanos, every court of appeals to have considered the
                question has determined that the government may exercise Clean Water
                Act jurisdiction over at least those waters that satisfy the
                significant nexus standard set forth in Justice Kennedy's concurrence.
                None has held that solely the plurality's relatively permanent standard
                may be used to establish jurisdiction. Some have held that the
                government may establish jurisdiction under either standard. The
                Eleventh Circuit has held that only Justice Kennedy's standard applies.
                Precon Dev. Corp. v. U.S. Army Corps of Eng'rs, 633 F.3d 278 (4th Cir.
                2011); see also United States v. Donovan, 661 F.3d 174 (3d Cir. 2011);
                United States v. Bailey, 571 F.3d 791 (8th Cir. 2009); United States v.
                Cundiff, 555 F.3d 200 (6th Cir. 2009); United States v. Lucas, 516 F.3d
                316 (5th Cir. 2008); N. Cal. River Watch v. City of Healdsburg, 496
                F.3d 993 (9th Cir. 2007) (superseding the original opinion published at
                457 F.3d 1023 (9th Cir. 2006)); United States v. Robison, 505 F.3d 1208
                (11th Cir. 2007); United States v. Johnson, 467 F.3d 56 (1st Cir.
                2006); United States v. Gerke Excavating, Inc., 464 F.3d 723 (7th Cir.
                2006).
                5. Post-Rapanos Implementation of the 1986 Regulations
                 For nearly a decade after Rapanos, the agencies did not revise
                their regulations but instead determined jurisdiction under the 1986
                regulations consistent with the two standards established in Rapanos
                (the relatively permanent standard and the significant nexus standard)
                and by using guidance issued jointly by the agencies. See U.S. EPA &
                U.S. Army Corps of Engineers, Clean Water Act Jurisdiction Following
                the U.S. Supreme Court's Decision in Rapanos v. United States &
                Carabell v. United States (June 5, 2007), superseded December 2, 2008
                (the ``Rapanos Guidance'').
                 Under the Rapanos Guidance,\12\ the agencies concluded that Clean
                Water Act jurisdiction exists if a water meets either the relatively
                permanent standard or the significant nexus standard. The agencies'
                assertion of jurisdiction over traditional navigable waters and their
                adjacent wetlands remained unchanged by Rapanos. Under the relatively
                permanent standard, the guidance stated that the agencies would assert
                jurisdiction over: Non-navigable tributaries of traditional navigable
                waters that typically flow year-round or have continuous flow at least
                seasonally; and wetlands that directly abut such tributaries. Id. at 4-
                7. The guidance states that the agencies will determine jurisdiction
                under the significant nexus standard for the following waters: Non-
                navigable tributaries that are not relatively permanent, wetlands
                adjacent to non-navigable tributaries that are not relatively
                permanent, and wetlands adjacent to but not directly abutting a
                relatively permanent non-navigable tributary. Id. at 8-12. The agencies
                generally did not assert jurisdiction over non-wetland swales or
                erosional features (e.g., gullies and small washes characterized by low
                volume or infrequent or short duration flow) or ditches (including
                roadside ditches) excavated wholly in and draining only uplands and
                that did not carry a relatively permanent flow of water. Id. at 11-12.
                ---------------------------------------------------------------------------
                 \12\ The agencies note that the guidance ``does not impose
                legally binding requirements on EPA, the Corps, or the regulated
                community, and may not apply to a particular situation depending on
                the circumstances.'' Rapanos Guidance at 4 n.17.
                ---------------------------------------------------------------------------
                B. The Agencies' Post-Rapanos Rules
                 Since 2015, EPA and the Army have finalized three rules revising
                the definition of ``waters of the United States.''
                [[Page 69381]]
                1. The 2015 Clean Water Rule
                 On June 29, 2015, EPA and the Army published the ``Clean Water
                Rule: Definition of `Waters of the United States,' '' 80 FR 37054 (June
                29, 2015). The 2015 Clean Water Rule's definition of ``waters of the
                United States'' established three categories: (A) Waters that are
                categorically ``jurisdictional by rule'' (without the need for
                additional analysis); (B) waters that are subject to case-specific
                analysis to determine whether they are jurisdictional; and (C) waters
                that are categorically excluded from jurisdiction. Id. at 37054. Waters
                considered ``jurisdictional by rule'' included (1) traditional
                navigable waters; (2) interstate waters, including interstate wetlands;
                (3) the territorial seas; (4) impoundments of waters otherwise
                identified as jurisdictional; (5) tributaries of the first three
                categories of ``jurisdictional by rule'' waters; and (6) waters
                adjacent to a water identified in the first five categories of
                ``jurisdictional by rule'' waters, including ``wetlands, ponds, lakes,
                oxbows, impoundments, and similar waters.'' Finally, all exclusions
                from the definition of ``waters of the United States'' in the pre-2015
                regulations were retained, and several exclusions reflecting agency
                practice or based on public comment were added to the regulation for
                the first time.\13\
                ---------------------------------------------------------------------------
                 \13\ In February 2018, the agencies issued a rule that added an
                applicability date of February 6, 2020 to the 2015 Clean Water Rule.
                83 FR 5200 (February 6, 2018) (``Applicability Date Rule''). The
                Applicability Date Rule was challenged in several district court
                actions and on August 16, 2018--a mere six months after the rule had
                been issued--the rule was vacated and enjoined nationwide. See South
                Carolina Coastal Conservation League v. Pruitt, 318 F. Supp. 3d 959
                (D.S.C. Aug. 16, 2018); see also Puget Soundkeeper All. v. Wheeler,
                No. 15-01342 (W.D. Wash. Nov. 26, 2018) (vacating the Applicability
                Date Rule nationwide).
                ---------------------------------------------------------------------------
                2. The 2019 Repeal Rule
                 On February 28, 2017, Executive Order 13778 ``Restoring the Rule of
                Law, Federalism, and Economic Growth by Reviewing the `Waters of the
                United States' Rule,'' directed EPA and the Army to review the 2015
                Clean Water Rule for consistency with the policy outlined in section 1
                of the order and to issue a proposed rule rescinding or revising the
                2015 rule as appropriate and consistent with law. 82 FR 12497 (March 3,
                2017). The Executive Order also directed the agencies to ``consider
                interpreting the term `navigable waters' . . . in a manner consistent
                with'' Justice Scalia's opinion in Rapanos. Id.
                 Consistent with this directive, after notice and comment, on
                October 22, 2019, the agencies published a final rule repealing the
                2015 Clean Water Rule and recodifying the 1986 regulations without any
                changes to the regulatory text. 84 FR 56626 (October 22, 2019).
                3. The 2020 Navigable Waters Protection Rule
                 Three months later, on January 23, 2020, the agencies signed
                another final rule--the Navigable Waters Protection Rule: Definition of
                ``Waters of the United States'' (NWPR)--that for the first time defined
                ``waters of the United States'' based generally on Justice Scalia's
                plurality test from Rapanos. The NWPR was published on April 21, 2020,
                and went into effect on June 22, 2020. 85 FR 22250 (April 21, 2020).
                The NWPR interpreted the term ``the waters'' within ``the waters of the
                United States'' to ``encompass relatively permanent flowing and
                standing waterbodies that are traditional navigable waters in their own
                right or that have a specific surface water connection to traditional
                navigable waters, as well as wetlands that abut or are otherwise
                inseparably bound up with such relatively permanent waters.'' Id. at
                22273. Specifically, the rule established four categories of
                jurisdictional waters: (1) The territorial seas and traditional
                navigable waters; (2) tributaries of such waters; (3) certain lakes,
                ponds, and impoundments of jurisdictional waters; and (4) wetlands
                adjacent to other jurisdictional waters (other than jurisdictional
                wetlands). Id. at 22273.
                 The NWPR defined the scope of each of these four categories. The
                territorial seas and traditional navigable waters were defined
                consistent with the agencies' longstanding interpretations of those
                terms. A ``tributary'' was defined as a river, stream, or similar
                naturally occurring surface water channel that contributes surface
                water flow to 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 was required to be perennial or intermittent in a typical
                year. The term ``tributary'' included a ditch that either relocates a
                tributary, is constructed in a tributary, or is constructed in an
                adjacent wetland as long as the ditch is perennial or intermittent and
                contributes surface water flow to a traditional navigable water or
                territorial sea in a typical year. Id. at 22251. The definition did not
                include ephemeral features, which were defined as surface waters that
                flow only in direct response to precipitation, including ephemeral
                streams, swales, gullies, rills, and pools. Id.
                 The NWPR defined ``lakes and ponds, and impoundments of
                jurisdictional waters'' as ``standing bodies of open water that
                contribute surface water flow in a typical year to a territorial sea or
                traditional navigable water either directly or through a tributary,
                another jurisdictional lake, pond, or impoundment, or an adjacent
                wetland.'' Id. A lake, pond, or impoundment of a jurisdictional water
                did not lose its jurisdictional status if it contributes surface water
                flow to a downstream jurisdictional water in a typical year through
                certain artificial or natural features. The NWPR also defined a lake,
                pond, or impoundment of a jurisdictional water inundated by flooding
                from a jurisdictional water in a typical year as jurisdictional. Id.
                 As for wetlands, the NWPR interpreted ``adjacent wetlands'' to be
                those wetlands that abut jurisdictional waters and those non-abutting
                wetlands that are (1) ``inundated by flooding'' from a jurisdictional
                water in a typical year, (2) physically separated from a jurisdictional
                water only by certain natural features (e.g., a berm, bank, or dune),
                or (3) physically separated from a jurisdictional water by an
                artificial structure that ``allows for a direct hydrologic surface
                connection'' between the wetland and the jurisdictional water in a
                typical year. Id. at 22251. Wetlands that do not have these types of
                connections to other waters were not jurisdictional.
                 The NWPR expressly provided that waters that do not fall into one
                of these jurisdictional categories are not considered ``waters of the
                United States.'' Id. Moreover, waters within these categories,
                including traditional navigable waters and the territorial seas, were
                not ``waters of the United States'' if they also fit within the NWPR's
                broad exclusions. See id. at 22325 (``If the water meets any of the[ ]
                exclusions, the water is excluded even if the water satisfies one or
                more conditions to be a [jurisdictional] water.'').\14\ The rule
                excluded groundwater, including groundwater drained through subsurface
                drainage systems; ephemeral features; diffuse stormwater runoff and
                directional sheet flow over upland; ditches that are not traditional
                navigable waters, tributaries, or that are not constructed in adjacent
                wetlands, subject to certain limitations; prior converted cropland;
                artificially irrigated areas; artificial lakes and ponds; water-filled
                depressions constructed or excavated in upland or in non-jurisdictional
                waters incidental to
                [[Page 69382]]
                mining or construction activity; pits excavated in upland or in non-
                jurisdictional waters for the purpose of obtaining fill, sand, or
                gravel; stormwater control features constructed or excavated in upland
                or in non-jurisdictional waters; groundwater recharge, water reuse, and
                wastewater recycling structures constructed or excavated in upland or
                in non-jurisdictional waters; and waste treatment systems.
                ---------------------------------------------------------------------------
                 \14\ The NWPR's exclusion for ditches, however, explicitly did
                not encompass ditches that are traditional navigable waters or
                jurisdictional tributaries. 33 CFR 328.3(b)(5).
                ---------------------------------------------------------------------------
                4. Legal Challenges to the Rules
                 Starting with the 2015 Clean Water Rule, the agencies' rulemakings
                to revise the definition of ``waters of the United States'' have been
                subject to multiple legal challenges.
                 Multiple parties sought judicial review of the 2015 Clean Water
                Rule in various district and circuit courts. On January 22, 2018, the
                Supreme Court, in a unanimous opinion, held that rules defining the
                scope of ``waters of the United States'' are subject to direct review
                in the district courts. Nat'l Ass'n of Mfrs. v. Dep't of Def., 138 S.
                Ct. 617 (2018). Several of those district court cases remain
                pending.\15\ While the 2015 Clean Water Rule went into effect in some
                parts of the country in August 2015, due to multiple injunctions \16\
                and later rulemakings, the 2015 Clean Water Rule was never implemented
                nationwide.
                ---------------------------------------------------------------------------
                 \15\ See, e.g., North Dakota v. EPA, No. 15-00059 (D.N.D.); Ohio
                v. EPA, No. 15-02467 (S.D. Ohio); Southeastern Legal Found. v. EPA,
                No. 15-02488 (N.D. Ga.).
                 \16\ See, e.g., North Dakota v. EPA, 127 F. Supp. 3d 1047
                (D.N.D. 2015) (preliminary injunction barring implementation of the
                2015 Clean Water Rule in 13 states); Georgia v. Pruitt, 326 F. Supp.
                3d 1356 (S.D. Ga. June 6, 2018) (same as to 11 states); Texas v.
                EPA, No. 3:15-cv-162, 2018 WL 4518230 (S.D. Tex. Sept. 12, 2018)
                (same as to 3 states). See section I.A of the Technical Support
                Document for the Proposed ``Revised Definition of `Waters of the
                United States''' Rule (``Technical Support Document''; located in
                the docket for this action), for a comprehensive history of the
                effects of the litigation against the 2015 Clean Water Rule.
                ---------------------------------------------------------------------------
                 A number of pending cases involve claims against the NWPR. On
                August 30, 2021, the U.S. District Court for the District of Arizona
                remanded the NWPR and vacated the rule. Pascua Yaqui Tribe v. EPA, No.
                4:20-cv-00266, 2021 WL 3855977 (D. Ariz. Aug. 30, 2021). The court
                found that ``[t]he seriousness of the Agencies' errors in enacting the
                NWPR, the likelihood that the Agencies will alter the NWPR's definition
                of `waters of the United States,' and the possibility of serious
                environmental harm if the NWPR remains in place upon remand, all weigh
                in favor of remand with vacatur.'' Id. at *5. On September 27, 2021,
                the U.S. District Court for the District of New Mexico also issued an
                order vacating and remanding the NWPR. Navajo Nation v. Regan, No.
                2:20-cv-00602 (D.N.M. Sept. 27, 2021). In vacating the rule, the court
                agreed with the reasoning of the Pascua Yaqui court that the NWPR
                suffers from ``fundamental, substantive flaws that cannot be cured
                without revising or replacing the NWPR's definition of `waters of the
                United States.''' Slip. op. at 6. Six courts also remanded the NWPR
                without vacatur or without addressing vacatur.\17\
                ---------------------------------------------------------------------------
                 \17\ Order, Pueblo of Laguna v. Regan, No. 1:21-cv-00277, ECF
                No. 40 (D.N.M. Sept. 21, 2021) (declining to reach issue of vacatur
                in light of the Pascua decision); Order, California v. Wheeler, No.
                3:20-cv-03005, ECF No. 271 (N.D. Cal. Sept. 16, 2021) (same);
                Waterkeeper All. v. Regan, No. 3:18-cv-03521, ECF No. 125 (N.D. Cal.
                Sept. 16, 2021) (same); Order, Conservation Law Found. v. EPA, No.
                1:20-cv-10820, ECF No. 122 (D. Mass. Sept. 1, 2021) (same); Order,
                S.C. Coastal Conservation League v. Regan, No. 2:20-cv-01687, ECF
                No. 147 (D.S.C. July 15, 2021) (remanding without vacating); Order,
                Murray v. Wheeler, No. 1:19-cv-01498, ECF No. 46 (N.D.N.Y. Sept. 7,
                2021) (same).
                ---------------------------------------------------------------------------
                 At this time, 14 cases are pending challenging the agencies' rules
                defining ``waters of the United States,'' including the 2015 Clean
                Water Rule, 2019 Repeal Rule, and the NWPR.\18\ Some of these cases
                challenge only one of the rules, while others challenge two or even all
                three rules in the same lawsuit. See section I.A of the Technical
                Support Document for a comprehensive history of the effects of the
                litigation surrounding the 2015 Clean Water Rule, 2019 Repeal Rule, and
                the NWPR.
                ---------------------------------------------------------------------------
                 \18\ Pascua Yaqui Tribe v. EPA, No. 20-00266 (D. Ariz.);
                Colorado v. EPA, No. 20-01461 (D. Colo.); Am. Exploration & Mining
                Ass'n v. EPA, No. 16-01279 (D.D.C.); Envtl. Integrity Project v.
                Regan, No. 20-01734 (D.D.C.); Se. Stormwater Ass'n v. EPA, No. 15-
                00579 (N.D. Fla.); Se. Legal Found. v. EPA, No. 15-02488 (N.D. Ga.);
                Chesapeake Bay Found. v. Regan, Nos. 20-1063 & 20-1064 (D. Md.);
                Navajo Nation v. Regan, No. 20-00602 (D.N.M.); N.M. Cattle Growers'
                Ass'n v. EPA, No. 19-00988 (D.N.M.); North Dakota v. EPA, No. 15-
                00059 (D.N.D.); Ohio v. EPA, No. 15-02467 (S.D. Ohio); Or.
                Cattlemen's Ass'n v. EPA, No. 19-00564 (D. Or.); S.C. Coastal
                Conservation League v. Regan, No. 19-03006 (D.S.C.); Puget
                Soundkeeper All. v. EPA, No. 20-00950 (W.D. Wash.); Wash.
                Cattlemen's Ass'n v. EPA, No. 19-00569 (W.D. Wash.).
                ---------------------------------------------------------------------------
                5. 2021 Executive Order and Review of the Navigable Waters Protection
                Rule
                 On January 20, 2021, President Biden signed Executive Order 13990,
                entitled ``Executive Order on Protecting Public Health and the
                Environment and Restoring Science to Tackle the Climate Crisis,'' which
                provides that ``[i]t is, therefore, the policy of my Administration to
                listen to the science; to improve public health and protect our
                environment; to ensure access to clean air and water; to limit exposure
                to dangerous chemicals and pesticides; to hold polluters accountable,
                including those who disproportionately harm communities of color and
                low-income communities; to reduce greenhouse gas emissions; to bolster
                resilience to the impacts of climate change; to restore and expand our
                national treasures and monuments; and to prioritize both environmental
                justice and the creation of the well-paying union jobs necessary to
                deliver on these goals.'' 86 FR 7037 (published January 25, 2021,
                signed January 20, 2021). The order ``directs all executive departments
                and agencies (agencies) to immediately review and, as appropriate and
                consistent with applicable law, take action to address the promulgation
                of Federal regulations and other actions during the last 4 years that
                conflict with these important national objectives, and to immediately
                commence work to confront the climate crisis.'' Id. at section 2(a).
                ``For any such actions identified by the agencies, the heads of
                agencies shall, as appropriate and consistent with applicable law,
                consider suspending, revising, or rescinding the agency actions.'' Id.
                The order also revoked Executive Order 13778 of February 28, 2017
                (Restoring the Rule of Law, Federalism, and Economic Growth by
                Reviewing the ``Waters of the United States'' Rule), which had
                initiated development of the NWPR.
                 In conformance with Executive Order 13990, the agencies reviewed
                the NWPR to determine if it is aligned with the principles laid out
                therein:
                 Science: Science plays a critical role in understanding how to
                protect the integrity of our nation's waters. As discussed in detail
                below, see section V.B.3 of this preamble, the NWPR did not properly
                consider the extensive scientific evidence demonstrating the
                interconnectedness of waters and their downstream effects, thereby
                undermining Congress's objective to restore and maintain the chemical,
                physical, and biological integrity of the nation's waters. The NWPR's
                definition of ``waters of the United States'' does not adequately
                consider the way pollution moves through waters or the way filling in a
                wetland affects downstream water resources.
                 Climate: Science has established that human and natural systems
                have been extensively impacted by climate change. Climate change can
                have a variety of impacts on water resources in particular. See
                Technical Support Document section III.C. For instance, a warming
                climate is already increasing precipitation in many areas (e.g., the
                Northeast and Midwest), while decreasing precipitation in other areas
                (e.g., the Southwest). Climate change can also increase the intensity
                of
                [[Page 69383]]
                precipitation events, including storms, and runoff from these storms
                can impair water quality as pollutants deposited on land wash into
                water bodies. Changes in streamflow, snowmelt timing, snowpack
                accumulation, and the size and frequency of heavy precipitation events
                can also cause river floods to become larger or more frequent than they
                used to be in some places. Climate change also affects streamflow
                characteristics like the magnitude and timing of flows, in part due to
                changes in snowpack magnitude and seasonality. As the climate continues
                to change, many historically dry areas are likely to experience less
                precipitation and increased risk of drought associated with more
                frequent and intense heatwaves, which can cause streams and wetlands to
                become drier, negatively affecting both water supplies and water
                quality. Lower streamflow and groundwater levels can also increase
                events such as wildfires, which can alter water quality and impact
                wetlands and their functions. A warming climate can also result in
                increased and more variable temperatures in streams, leading to fish
                kills and negatively affecting other aquatic species that can live only
                in colder water. Finally, rising sea levels associated with climate
                change are inundating low-lying wetlands and dry land and further
                contributing to coastal flooding and erosion.
                 Although water resources are vulnerable to the effects of climate
                change, they perform a variety of functions that can help restore
                ecological function of other water resources in light of climate change
                (i.e., contribute to climate resiliency) and mitigate the negative
                effects of climate change on other water resources including
                traditional navigable waters, interstate waters, and the territorial
                seas. For instance, wetlands inside and outside of floodplains are
                well-known to store large volumes of floodwaters, thereby protecting
                downstream watersheds from potential flooding. Coastal wetlands can
                also help buffer storm surges, which are becoming more frequent due to
                climate change. Additionally, small streams are particularly effective
                at retaining and attenuating floodwaters. As natural filters, wetlands
                help purify and protect the quality of other waters, including drinking
                water sources--a function which is more important than ever as intense
                precipitation events spurred on by a changing climate mobilize
                sediment, nutrients, and other pollutants. Biological communities and
                geomorphic processes in small streams and wetlands break down leaves
                and other organic matter, burying and sequestering a portion of that
                carbon that could otherwise be released to the atmosphere and lead to
                continued negative effects on water resources.
                 The NWPR did not appropriately acknowledge or take account of the
                effects of a changing climate on the chemical, physical, and biological
                integrity of the nation's waters. For example, its rolling thirty-year
                approach to determining a ``typical year'' does not allow the agencies
                flexibility to account for the effects of a rapidly changing climate,
                including positive trends in temperature, increasing storm events, and
                extended droughts (see section V.B.3.c of this preamble). The NWPR also
                excluded ephemeral streams and their adjacent wetlands in the arid West
                from the definition of ``waters of the United States.'' These aquatic
                systems are increasingly critical to protecting and maintaining
                downstream integrity as the climate in that region continues to get
                hotter and drier, but with altered monsoon seasons with fewer but more
                intense storms that contribute to flashy hydrology (i.e., higher runoff
                volume, leading to more rapidly rising and falling streamflow over
                shorter periods of time).
                 Section V.A.2.c.iv of this preamble contains a discussion of how
                the agencies believe that climate change can be appropriately
                considered in implementing the proposed rule.
                 Environmental Justice: The agencies recognize that the burdens of
                environmental pollution and climate change often fall
                disproportionately on population groups of concern (e.g., minority,
                low-income, and indigenous populations as specified in Executive Order
                12898). Numerous groups have raised concerns that the NWPR had
                disproportionate impacts on tribes and indigenous communities.\19\ The
                NWPR decreased the scope of Clean Water Act jurisdiction across the
                country, including in geographic regions where regulation of waters
                beyond those covered by the Act is not authorized under current state
                or tribal law (see section V.B.3.d of this preamble). Absent
                regulations governing discharges of pollutants into previously
                jurisdictional waters, population groups of concern where these waters
                are located may experience increased water pollution and impacts from
                associated increases in health risk.
                ---------------------------------------------------------------------------
                 \19\ See, e.g., Tribal Consultation Comment Letter from
                President Jonathan Nez and Vice President Myron Lizer, Navajo
                Nation, October 4, 2021 (``The Navajo Nation relies greatly on all
                its surface waters, including ephemeral, intermittent, and perennial
                surface waters. The Navajo Nation currently lacks the resources to
                implement CWA permitting and other programs necessary to maintain
                and protect water quality and relies on the Agencies to fill that
                need. Therefore, any new WOTUS rule must not reduce the scope of the
                waters that the Agencies can protect, or it will have
                `disproportionately high and adverse human health or environmental
                effects' on the Navajo Nation.''), and Tribal Consultation Comment
                Letter from Clarice Madalena, Interim Director, Natural Resources
                Department, Pueblo of Jemez, October 4, 2021 (``The combination of
                these factors--[desert] hydrology and the geographic location of
                Native communities--means that the Navigable Waters Rule had the
                effect of disparately stripping Clean Water Act protections from
                areas with higher Native populations. This means that the Rule
                disproportionately harmed Native American communities. This
                discriminatory impact violates the principles of environmental
                justice'' (citations omitted). See, also, section V.B.3.d of this
                preamble and the Technical Support Document.
                ---------------------------------------------------------------------------
                 Further, the NWPR categorically excluded ephemeral streams from
                jurisdiction, which disproportionately impacts tribes and population
                groups of concern in the arid West. Tribes may lack the authority and
                often the resources to regulate waters within their boundaries, and
                they may also be affected by pollution from adjacent jurisdictions.\20\
                Therefore, the change in jurisdiction under the NWPR may have
                disproportionately exposed tribes to increased pollution and health
                risks.
                ---------------------------------------------------------------------------
                 \20\ See supra at note 18.
                ---------------------------------------------------------------------------
                 After completing the review and reconsidering the record for the
                NWPR, on June 9, 2021, the agencies announced their intention to revise
                or replace the rule. The factors the agencies found most relevant in
                making this decision are: The text of the Clean Water Act;
                Congressional intent and the objective of the Clean Water Act; Supreme
                Court precedent; the current and future harms to the chemical,
                physical, and biological integrity of the nation's waters due to the
                NWPR; concerns raised by stakeholders about the NWPR, including
                implementation-related issues; the principles outlined in the Executive
                Order; and issues raised in ongoing litigation challenging the NWPR.
                EPA and the Army concluded that the NWPR did not appropriately consider
                the effect of the revised definition of ``waters of the United States''
                on the integrity of the nation's waters, and that the rule threatened
                the loss or degradation of waters critical to the protection of
                traditional navigable waters, among other concerns.
                C. Summary of Stakeholder Outreach
                 EPA held a series of stakeholder meetings during the agencies'
                review of the NWPR, including specific meetings in May 2021 with
                industry, environmental organizations, agricultural organizations, and
                state associations. On July 30, 2021, the
                [[Page 69384]]
                agencies signed a Federal Register notice that announced a schedule for
                initial public meetings to hear from interested stakeholders on their
                perspectives on defining ``waters of the United States'' under the
                Clean Water Act and how to implement the definition. 86 FR 41911
                (August 4, 2021). The agencies also announced their intent to accept
                written pre-proposal recommendations from members of the public for a
                30-day period beginning on August 4, 2021, and concluding on September
                3, 2021. The agencies received over 32,000 recommendation letters from
                the public, which can be found in the pre-proposal docket (Docket ID
                EPA-HQ-OW-2021-0328). The agencies also announced their plans for
                future engagement opportunities, including geographically focused
                roundtables to provide for broad, transparent, regionally focused
                discussions among a full spectrum of stakeholders. The Federal Register
                notice articulated several specific issues that the agencies are
                particularly interested in receiving feedback on, including
                implementation of previous regulatory regimes; regional, state, and
                tribal interests; identification of relevant science; environmental
                justice interests; climate implications; the scope of jurisdictional
                waters such as tributaries, jurisdictional ditches, and adjacent
                features; and exclusions from jurisdiction.
                 The agencies also have engaged state and local governments over a
                60-day federalism consultation period during development of this
                proposed rule, beginning with an initial federalism consultation
                meeting on August 5, 2021, and concluding on October 4, 2021.
                Additional information about the federalism consultation can be found
                in section VII.E of this preamble and in the report summarizing
                consultation and additional outreach to state and local governments,
                available in the docket (Docket ID No. EPA-HQ-OW-2021-0602) for this
                proposed rule. On September 29, October 6, and October 20, 2021, the
                agencies hosted virtual meetings with states focused on implementation
                of prior ``waters of the United States'' regulatory regimes.
                 The agencies received input from a wide variety of states and local
                governments through virtual meetings, consultation letters, and
                recommendation letters submitted to the public docket. Many of these
                groups encouraged meaningful dialogue between the states, local
                governments, and the agencies, and identified implementation challenges
                with determining the jurisdiction of waters under the pre-2015
                regulatory regime. States and local governments stressed the need for
                guidance, training, and tools early in the process to help with
                implementing any revised definition of ``waters of the United States.''
                A few also requested the agencies to consider a delayed effective date
                for revised definitions of ``waters of the United States'' to give
                state and local partners time to revise and develop new policies. Many
                state and local governments emphasized the variability of water
                resources across the United States and supported regionalized criteria
                for determining jurisdictional waters. Some of these groups noted the
                importance of strong Federal standards and the regulation of interstate
                waters, since pollutants from upstream states can enter waters within
                their borders.
                 States and local governments held divergent views on the agencies'
                plans to revert to the pre-2015 regulatory regime, and on which water
                resources should be considered ``waters of the United States.'' Some
                supported the NWPR and recommended the agencies generally retain and
                revise that rule. These state and local entities believed that the NWPR
                provided a clear definition for ``waters of the United States,''
                maintained a balance between federal and state jurisdiction, and
                appropriately excluded waters that should not be subject to the Clean
                Water Act. Others supported the agencies' current rulemaking efforts as
                they thought the NWPR was not protective enough and did not account for
                the complexities of the hydrologic cycle, importance of ephemeral
                waters, or the connections among waters on the landscape. State and
                local governments held differing opinions on how the criteria for
                jurisdiction of ephemeral streams, ditches, tributaries, and wetlands
                should be determined, and which resources should be included in the
                scope of the Clean Water Act.
                 Several state and local governments recommended consideration of
                climate change and environmental justice concerns in any new rulemaking
                effort. Some emphasized that isolated wetlands and ephemeral streams
                are important in reducing flooding during extreme weather events and
                that the agencies should consider this importance in the rulemaking.
                Others acknowledged the impacts of climate change but stated that other
                programs and legislation are more appropriate ways to address climate
                change. Some state and local governments also noted that NWPR excluded
                wetlands that are important to minority and low-income communities and
                that future rulemaking needs to consider environmental justice issues.
                 The agencies also initiated a tribal consultation and coordination
                process on July 30, 2021. The agencies engaged tribes over a 66-day
                tribal consultation period during development of this proposed rule
                that concluded on October 4, 2021, including two consultation kick-off
                webinars and meetings. The agencies received consultation comment
                letters from 24 tribes and three tribal organizations and held three
                leader-to-leader consultation meetings and two staff-level meetings
                with tribes at their request. The agencies anticipate that consultation
                meetings with additional tribes will be held with tribes during the
                rulemaking process. Many tribes and tribal organizations expressed
                support for the agencies' efforts to replace the NWPR. One tribe did
                not support the agencies' efforts to revise the definition of ``waters
                of the United States,'' stating tribal sovereignty concerns and
                concerns that the agencies might exceed the power of Congress under the
                Commerce Clause. Some tribes stated that the NWPR disadvantaged tribes
                because unlike states, many tribes lack the resources to enforce a
                definition of ``tribal waters'' that is broader than the definition of
                ``waters of the United States.'' Several tribes also stated that they
                rely on the Federal government to permit discharges of pollutants into
                waters on their lands and do not have the resources to administer their
                own permitting programs. Some tribes spoke of the importance of
                protecting ephemeral streams, which were eliminated from jurisdiction
                under the NWPR, as well as for wetlands that were excluded under the
                NWPR. Several tribes spoke about the need to include ``waters of the
                tribe'' into the definition of ``waters of the United States'' Several
                tribes stated support for furthering environmental justice with the
                proposed rule, noting that the agencies failed to undertake an
                environmental justice analysis for the NWPR. Some tribes also supported
                the need to account for climate change in the definition of ``waters of
                the United States.'' Additional information about the tribal
                consultation process can be found in section VII.F of this preamble and
                the Summary of Tribal Consultation and Coordination, which is available
                in the docket for this proposed rule. On October 7, 13, 27, and 28,
                2021, the agencies hosted virtual dialogues with tribes focused on
                implementation of prior ``waters of the United States'' regulatory
                regimes.
                 Consistent with the August 4, 2021 Federal Register notice, the
                agencies held six public meeting webinars on
                [[Page 69385]]
                August 18, August 23, August 25 (specifically for small entities),
                August 26, August 31, and September 2, 2021. At these pre-proposal
                webinars, the agencies provided a brief presentation and sought input
                on the agencies' intent to revise the definition of ``waters of the
                United States'' and the specific issues included in the outreach
                Federal Register notice described above. The agencies heard from
                stakeholders representing a diverse range of interests, positions,
                suggestions, and recommendations.
                 The agencies have received a variety of recommendations during this
                pre-proposal outreach process. The agencies received broad support for
                robust stakeholder outreach and the development of a rule that is
                consistent with Supreme Court precedent. Stakeholders disagreed about
                whether states and tribes could or would fill any perceived gap in
                permitting introduced by the NWPR's decreased scope of jurisdiction,
                with some stakeholders providing examples of environmental harms caused
                by the NWPR. Some stakeholders expressed support for a science-based
                rule, including stakeholders who believed the NWPR did not adequately
                consider the agencies' scientific record. Most stakeholders who
                provided input supported a clear, implementable rule that is easy for
                the public to understand, and the agencies received feedback that the
                significant nexus standard and typical year analysis were challenging
                to implement under prior regulatory regimes.
                 Many stakeholders also emphasized the importance of regional
                geographic variability across the United States, and some stakeholders
                suggested that the agencies consider regionally specific criteria for
                jurisdictional waters. Some stakeholders emphasized the importance of
                climate change considerations in any new rulemaking effort, while other
                stakeholders stated that climate change cannot be used as a tool to
                expand jurisdictional authority. Some stakeholders explicitly supported
                the consideration of impacts to minority and low-income communities in
                developing a revised definition of ``waters of the United States'' and
                asserted that the NWPR did not consider impacts to these communities.
                 Stakeholders also provided feedback on which water resources should
                be considered jurisdictional as ``waters of the United States.'' For
                instance, some stakeholders supported a jurisdictional category for
                interstate waters, while others opposed such a category. Stakeholders
                differed in whether they supported the criteria for jurisdictional
                tributaries, wetlands, and ditches under the pre-2015 regulatory
                regime, 2015 Clean Water Rule, or NWPR. Some stakeholders suggested
                that the agencies should enhance clarity by using physical indicators,
                functional characteristics, or surface water flow as jurisdictional
                criteria. Some stakeholders asserted that the agencies should exclude
                most ditches from the definition of ``waters of the United States,''
                while others stated that the agencies should instead include ditches as
                jurisdictional if they function as tributaries or have other
                connections to other hydrologic features in the watershed. Some
                stakeholders indicated that impoundments and ``other waters'' are not
                appropriate categories of jurisdictional waters, while others suggested
                regulating a broad spectrum of open waters.
                 Stakeholders expressed different views about which exclusions are
                important and should be included in a revised definition of ``waters of
                the United States.'' Many stakeholders noted that the waste treatment
                system exclusion and prior converted cropland exclusion should be
                retained, and some stakeholders expressed support for other exclusions
                such as stormwater control features and artificial lakes and ponds. As
                described in section V.C.8 of this preamble, the agencies are proposing
                to retain the waste treatment system exclusion and prior converted
                cropland exclusion from the 1986 regulations and have specified in the
                preamble that certain other waters are generally not considered
                ``waters of the United States.'' Stakeholders also had divergent views
                on whether ephemeral streams should be categorically excluded from the
                definition of ``waters of the United States'' or evaluated as
                tributaries. As described in section V.C.5 of this preamble, the
                agencies are not proposing to exclude ephemeral streams but are instead
                proposing that ephemeral streams that meet the significant nexus
                standard be jurisdictional as tributaries.
                 The agencies have considered the input that they received as part
                of the consultation processes and other opportunities for pre-proposal
                recommendations. The proposed rule, discussed in section V of this
                preamble, seeks to balance the considerations and concerns of co-
                regulators and stakeholders. The agencies welcome feedback on this
                proposed rule through a public hearing and the 60-day public comment
                period initiated through publication of this action. The agencies will
                consider all comments received during the comment period on this
                proposal, and this consideration will be reflected in the final rule
                and supporting documents.
                V. Proposed Revised Definition
                A. Basis for Proposed Rule
                 In this proposed rule, the agencies are exercising their
                discretionary authority to interpret ``waters of the United States'' to
                mean the waters defined by the familiar 1986 regulations, with
                amendments to reflect the agencies' determination of the statutory
                limits on the scope of the ``waters of the United States'' informed by
                Supreme Court precedent. The agencies propose to interpret the term
                ``waters of the United States'' to include: Traditional navigable
                waters, interstate waters, and the territorial seas, and their adjacent
                wetlands; most impoundments of ``waters of the United States'';
                tributaries to traditional navigable waters, interstate waters, the
                territorial seas, and impoundments, that meet either the relatively
                permanent standard or the significant nexus standard; wetlands adjacent
                to impoundments and tributaries, that meet either the relatively
                permanent standard or the significant nexus standard; and ``other
                waters'' that meet either the relatively permanent standard or the
                significant nexus standard.
                 The proposed rule advances the Clean Water Act's statutory
                objective to ``restore and maintain the chemical, physical, and
                biological integrity of the Nation's waters,'' section 101(a), as it is
                based on the best available science concerning the functions provided
                by upstream tributaries, adjacent wetlands, and ``other waters'' to
                restore and maintain the water quality of downstream foundational
                waters. In developing the proposed rule, the agencies also considered
                the statute as a whole, relevant Supreme Court case law, and the
                agencies' experience and expertise after more than 30 years of
                implementing the longstanding 1986 regulations defining ``waters of the
                United States,'' including more than a decade of experience
                implementing those regulations consistent with the decisions in
                Riverside Bayview, SWANCC, and Rapanos collectively. This proposed
                interpretation also reflects consideration of provisions of the Act
                including section 101(b) which states that ``[i]t is the policy of the
                Congress to recognize, preserve, and protect the primary
                responsibilities and rights of States to prevent, reduce, and eliminate
                pollution, to plan the development and use (including restoration,
                preservation, and enhancement) of land and water resources'' because
                the limitations
                [[Page 69386]]
                reflect consideration of both the comprehensive nature and objective of
                the Clean Water Act and avoid assertions of jurisdiction that raise
                federalism concerns. Determining where to draw the boundaries of
                federal jurisdiction to ensure that the agencies achieve Congress's
                objective while preserving and protecting the responsibilities and
                rights of the states is a matter of judgment assigned by Congress to
                the agencies. The proposed rule's relatively permanent and significant
                nexus limitations appropriately draw this boundary by ensuring that
                where upstream waters significantly affect the integrity of the
                traditional navigable waters, interstate waters, and territorial seas,
                Clean Water Act programs will apply to ensure that those downstream
                waters are protected, and where they do not, the agencies will leave
                regulation to the states and tribes. These limitations are thus based
                on the agencies' conclusion that together those standards are
                consistent with the statutory text, advance the objective of the Act,
                are supported by the scientific record, and appropriately consider the
                objective in section 101(a) of the Act and the policy in section
                101(b). In addition, because the proposed rule reflects consideration
                of the agencies' experience and expertise, as well as updates in
                implementation tools and resources, it is familiar and implementable.
                 For all these reasons, the proposed rule would achieve the
                agencies' goals of quickly and durably protecting the quality of the
                nation's waters. Quickly, because the regulatory framework is familiar
                to the agencies and stakeholders and supporting science is available
                along with confirmatory updates; and durably, because the foundation of
                the rule is the longstanding regulations amended to reflect the
                agencies' interpretation of appropriate limitations on the geographic
                scope of the Clean Water Act that is consistent with case law, the Act,
                and the best available science. The proposal would protect the quality
                of the nation's waters by restoring the important protections for
                jurisdictional waters provided by the Clean Water Act, including not
                only protections provided by the Act's permitting programs, but also
                protections provided by programs ranging from water quality standards
                and total maximum daily loads to oil spill prevention, preparedness and
                response programs, to the state and tribal water quality certification
                programs.
                 The proposed rule is based on the agencies' interpretation of the
                Clean Water Act, and the proposed rule's protection of water resources
                advances both the goals of the Act and the goals identified in the
                Executive Order, including: Listening to the science; improving public
                health and protecting our environment; ensuring access to clean water;
                limiting exposure to dangerous chemicals and pesticides; holding
                polluters accountable, including those who disproportionately harm
                communities of color and low-income communities; and bolstering
                resilience to the impacts of climate change.
                1. The Proposed Rule Is Within the Agencies' Discretion Under the Act
                 The Clean Water Act delegates authority to the agencies to
                interpret the term ``navigable waters'' and its statutory definition
                ``waters of the United States,'' and agencies have inherent authority
                to reconsider past decisions and to revise, replace, or repeal a
                decision to the extent permitted by law and supported by a reasoned
                explanation. Given the regulatory and litigation history described
                above, there can be little disagreement that both terms under the Clean
                Water Act are ambiguous and that therefore the agencies have generous
                leeway to provide the considered and reasonable interpretation of the
                terms provided in this proposal. Indeed, the Supreme Court has twice
                held that the Act's terms ``navigable waters'' and ``waters of the
                United States'' are ambiguous and, therefore, that the agencies have
                delegated authority to reasonably interpret this phrase in the statute.
                 First, in Riverside Bayview, the Supreme Court deferred to and
                upheld the agencies' interpretation of the Act to protect wetlands
                adjacent to navigable-in-fact bodies of water, relying on the familiar
                Chevron standard that ``[a]n agency's construction of a statute it is
                charged with enforcing is entitled to deference if it is reasonable and
                not in conflict with the expressed intent of Congress.'' 474 U.S. at
                131 (citing Chevron U.S.A. Inc. v. Natural Resources Defense Council,
                Inc., 467 U.S. 837, 842-45 (1984)). Second, in Rapanos, all Justices
                found ambiguity in the terms--albeit to varying degrees. In his
                concurring opinion, Justice Kennedy referenced ``ambiguity in the
                phrase `navigable waters.' '' 547 U.S. at 780. So did the dissenting
                Justices. See id. at 796 (``[G]iven the ambiguity inherent in the
                phrase `waters of the United States,' the Corps has reasonably
                interpreted its jurisdiction[.]'') (Stevens, J., dissenting); id. at
                811-12 (``Congress intended the Army Corps of Engineers to make the
                complex technical judgments that lie at the heart of the present cases
                (subject to deferential judicial review).'') (Breyer, J., dissenting).
                The plurality also agreed that the term ``is in some respects
                ambiguous.'' Id. at 752.
                 Ambiguity in a statute represents ``delegations of authority to the
                agency to fill the statutory gap in reasonable fashion.'' Nat'l Cable &
                Telecomm. Ass'n v. Brand X internet Servs., 545 U.S. 967, 980 (2005).
                As the Supreme Court explained in Riverside Bayview, Congress delegated
                a ``breadth of federal regulatory authority'' and expected the agencies
                to tackle the ``inherent difficulties of defining precise bounds to
                regulable waters.'' 474 U.S. at 134. And, in concurring with the
                Rapanos plurality opinion, Chief Justice Roberts emphasized the breadth
                of the agencies' discretion in defining ``waters of the United States''
                through rulemaking, noting that ``[g]iven the broad, somewhat
                ambiguous, but nonetheless 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 Clean Water Act. 547 U.S. at 758 (Roberts,
                C.J., concurring). Indeed, the agencies' interpretations under the Act,
                Chief Justice Roberts emphasized, are ``afforded generous leeway by the
                courts.'' Id.
                 In addition, agencies have inherent authority to reconsider past
                decisions and to revise, replace, or repeal a decision to the extent
                permitted by law and supported by a reasoned explanation. FCC v. Fox
                Television Stations, Inc., 556 U.S. 502, 515 (2009) (``Fox''); Motor
                Vehicle Manufacturers Ass'n of the United States, Inc. v. State Farm
                Mutual Automobile Insurance Co., 463 U.S. 29, 42 (1983) (``State
                Farm''); see also Encino Motorcars, LLC v. Navarro, 136 S. Ct. 2117,
                2125 (2016) (``Agencies are free to change their existing policies as
                long as they provide a reasoned explanation for the change.''). Such a
                decision need not be based upon a change of facts or circumstances. A
                revised rulemaking based ``on a reevaluation of which policy would be
                better in light of the facts'' is ``well within an agency's
                discretion.'' Nat'l Ass'n of Home Builders v. EPA, 682 F.3d 1032, 1038
                & 1043 (D.C. Cir. 2012) (citing Fox, 556 U.S. at 514-15).
                 As discussed further in section V.B.3 of this preamble, the
                agencies have reviewed the NWPR and determined that the rule should be
                replaced. The proposed rule properly considers the objective of the
                Act, is consistent with the text and structure of the Act and
                [[Page 69387]]
                Supreme Court precedent, and is supported by the best available
                science.
                2. The Proposed Rule Advances the Objective of the Clean Water Act
                 The proposed rule is grounded in the Act's objective ``to restore
                and maintain the chemical, physical, and biological integrity of the
                Nation's waters,'' 33 U.S.C. 1251(a). The proposed rule advances the
                Act's objective by defining ``waters of the United States'' to include
                waters that significantly affect the chemical, physical, or biological
                integrity of traditional navigable waters, interstate waters, and the
                territorial seas and waters that are relatively permanent or that have
                a continuous surface connection to such waters. Those limitations also
                ensure that the agencies will not assert jurisdiction where the effect
                is not significant. The proposed rule is supported by the best
                available science on the functions provided by upstream waters,
                including wetlands, to restore and maintain the integrity of
                foundational waters because it recognizes that upstream waters can have
                significant effects and enables the agencies to make science-informed
                decisions about such effects. The proposed rule thus retains the
                familiar categories of waters in the 1986 regulations--traditional
                navigable waters, interstate waters, ``other waters,'' impoundments,
                tributaries, the territorial seas, and adjacent wetlands--while
                proposing to add, where appropriate, a requirement that waters also
                meet either the significant nexus standard or the relatively permanent
                standard.
                a. The Objective of the Clean Water Act To Protect Water Quality Must
                Be Considered When Defining ``Waters of the United States''
                 A statute must be interpreted in light of the purposes Congress
                sought to achieve. See, e.g., Dickerson v. New Banner Institute, Inc.,
                460 U.S. 103, 118 (1983). Thus, the agencies must consider the
                objective of the Clean Water Act in interpreting the scope of the
                statutory term ``waters of the United States.'' The objective of the
                Clean Water Act is ``to restore and maintain the chemical, physical,
                and biological integrity of the Nation's waters.'' 33 U.S.C. 1251(a).
                To thus adequately consider the Act's statutory objective, a rule
                defining ``waters of the United States'' must consider its effects on
                the chemical, physical, and biological integrity of the nation's
                waters. And--as the text and structure of the Act, supported by
                legislative history and Supreme Court decisions, make clear--chemical,
                physical, and biological integrity refers to water quality.
                 The Act begins with the objective in section 101(a) and establishes
                numerous programs all designed to protect the integrity of the nation's
                waters, ranging from permitting programs and enforcement authorities,
                to water quality standards and effluent limitations guidelines, to
                research and grant provisions.
                 One of the Clean Water Act's principal tools in protecting the
                integrity of the nation's waters is section 301(a), which prohibits
                ``the discharge of any pollutant by any person'' without a permit or
                other authorization under the Act. Other substantive provisions of the
                Clean Water Act that apply to ``navigable waters'' and are designed to
                meet the statutory objective include the section 402 NPDES permit
                program, the section 404 dredged and fill permit program, the section
                311 oil spill prevention and response program, the section 303 water
                quality standards and total maximum daily load programs, and the
                section 401 state and tribal water quality certification process, as
                discussed above. Each of these programs is designed to protect water
                quality and, therefore, further the objective of the Act. The question
                of federal jurisdiction is foundational to most programs administered
                under the Clean Water Act. See section IV.A.1 of this preamble.\21\
                ---------------------------------------------------------------------------
                 \21\ Additional provisions are also designed to achieve the
                Act's statutory objective and use its specific language, including
                the definition of ``pollution,'' which the Act defines as ``the man-
                made or man-induced alteration of the chemical, physical,
                biological, and radiological integrity of water.'' 33 U.S.C.
                1362(19).
                ---------------------------------------------------------------------------
                 Two recent Supreme Court Clean Water Act decisions, County of Maui,
                Hawaii v. Hawaii Wildlife Fund, 140 S. Ct. 1462, 1476 (2020) (``Maui'')
                and Nat'l Ass'n of Mfrs. v. Dep't of Defense, 138 S. Ct. 617, 624
                (2018) (``National Association of Manufacturers''), affirm that
                Congress used specific language in the definitions of the Act in order
                to meet the objective of the Act, that the definition of ``waters of
                the United States'' is fundamental to meeting the objective of the Act,
                and, therefore, that the objective of the Act must be considered in
                interpreting the term ``waters of the United States.''
                 In Maui, the Supreme Court instructed that ``[t]he object in a
                given scenario will be to advance, in a manner consistent with the
                statute's language, the statutory purposes that Congress sought to
                achieve.'' 140 S. Ct. at 1476. The Court, in recognizing that
                Congress's purpose to `` `restore and maintain the . . . integrity of
                the Nation's waters' '' is ``reflected in the language of the Clean
                Water Act,'' also found that ``[t]he Act's provisions use specific
                definitional language to achieve this result,'' noting that among that
                definitional language is the phrase ``navigable waters.'' Id. at 1468-
                69.\22\ Thus, in accordance with Maui, in interpreting the ``specific
                definitional language'' of the Clean Water Act, the agencies must
                consider whether they are advancing the statutory purposes Congress
                sought to achieve.
                ---------------------------------------------------------------------------
                 \22\ The Court explained:
                 The Act's provisions use specific definitional language to
                achieve this result. First, the Act defines ``pollutant'' broadly,
                including in its definition, for example, any solid waste,
                incinerator residue, `` `heat,' '' `` `discarded equipment,' '' or
                sand (among many other things). Sec. 502(6), 86 Stat. 886. Second,
                the Act defines a ``point source'' as `` `any discernible, confined
                and discrete conveyance . . . from which pollutants are or may be
                discharged,' '' including, for example, any `` `container,' '' ``
                `pipe, ditch, channel, tunnel, conduit,' '' or `` `well.' '' Sec.
                502(14), id., at 887. Third, it defines the term ``discharge of a
                pollutant'' as `` `any addition of any pollutant to navigable waters
                [including navigable streams, rivers, the ocean, or coastal waters]
                from any point source.' '' Sec. 502(12), id., at 886.
                 Maui, 140 S. Ct. at 1469.
                ---------------------------------------------------------------------------
                 In National Association of Manufacturers, the Court confirmed the
                importance of considering the objective of the Clean Water Act when
                interpreting the specific definitional language of the Act, and in
                particular when interpreting the definitional language ``waters of the
                United States.'' The Court identified section 301's prohibition on
                unauthorized discharges as one of the Act's principal tools for
                achieving the objective and then identified ``waters of the United
                States'' as key to the scope of the Act: ``Congress enacted the Clean
                Water Act in 1972 `to restore and maintain the chemical, physical, and
                biological integrity of the Nation's waters.' [33 U.S.C.] 1251(a). One
                of the Act's principal tools in achieving that objective is [section]
                1311(a), which prohibits `the discharge of any pollutant by any
                person,' except in express circumstances. . . . Because many of the
                Act's substantive provisions apply to `navigable waters,' the statutory
                phrase `waters of the United States' circumscribes the geographic scope
                of the Act in certain respects.'' 138 S. Ct. 617, 624. Thus,
                consideration of the objective of the Act is of particular importance
                when defining the foundational phrase ``waters of the United States.''
                 Many other Supreme Court decisions confirm the importance of
                considering the Act's objective. When faced with questions of statutory
                interpretation on the scope of the Clean Water Act, many Supreme Court
                decisions begin with the
                [[Page 69388]]
                objective of the Act and examine the relevant question through that
                lens. See, e.g., PUD No. 1 of Jefferson Cty v. Washington Dep't of
                Ecology, 511 U.S. 700, 704 (1994) (interpreting the scope of Clean
                Water Act section 401 and finding that the Act ``is a comprehensive
                water quality statute designed to `restore and maintain the chemical,
                physical, and biological integrity of the Nation's waters,' '' that
                ``[t]he Act also seeks to attain `water quality which provides for the
                protection and propagation of fish, shellfish, and wildlife,' '' and
                that ``[t]o achieve these ambitious goals, the Clean Water Act
                establishes distinct roles for the Federal and State Governments'');
                EPA v. California ex rel. State Water Resources Control Bd., 426 U.S.
                200, 203, 205 n.12 (1976) (``In 1972, prompted by the conclusion of the
                Senate Committee on Public Works that `the Federal water pollution
                control program . . . has been inadequate in every vital aspect,'
                Congress enacted the [Clean Water Act], declaring `the national goal
                that the discharge of pollutants into the navigable waters be
                Eliminated by 1985.''); Arkansas v. Oklahoma, 503 U.S. 91 (1992)
                (reviewing the scope of EPA's authority to issue a permit affecting a
                downstream state and finding that the Act ``anticipates a partnership
                between the States and the Federal Government, animated by a shared
                objective: `to restore and maintain the chemical, physical, and
                biological integrity of the Nation's waters' ''); S.D. Warren Co. v.
                Maine Bd. of Envtl. Protection, 126 S. Ct. 1843, 1852-53 (2006)
                (interpreting the scope of ``discharge'') (``Congress passed the Clean
                Water Act to `restore and maintain the chemical, physical, and
                biological integrity of the Nation's waters,' 33 U.S.C. [section]
                1251(a)''); Int'l Paper Co. v. Ouellette, 479 U.S. 481, 492-93 (1987)
                (``Congress intended the 1972 Act amendments to `establish an all-
                encompassing program of water pollution regulation.' . . . The Act
                applies to all point sources and virtually all bodies of water, and it
                sets forth the procedures for obtaining a permit in great detail. . . .
                Given that the Act itself does not speak directly to the issue, the
                Court must be guided by the goals and policies of the Act in
                determining whether it in fact pre-empts an action based on the law of
                an affected State.'').
                 Along with Maui and National Association of Manufacturers, these
                cases confirm that, for purposes of a rulemaking revising the
                definition of ``waters of the United States,'' the agencies must
                consider the rule's effect on the chemical, physical, and biological
                integrity of the nation's waters--i.e., the quality of those waters.
                The Supreme Court in Riverside Bayview explained the inherent link
                between the Act's objective and water quality: ``This objective
                incorporated a broad, systemic view of the goal of maintaining and
                improving water quality: As the House Report on the legislation put it,
                `the word ``integrity'' . . . refers to a condition in which the
                natural structure and function of ecosystems [are] maintained.' '' 474
                U.S. at 132 (citations omitted).
                 Indeed, the Clean Water Act is replete with 90 references to water
                quality--from the goals set forth in furtherance of meeting the
                statutory objective to the provisions surrounding research, effluent
                limitations, and water quality standards. See, e.g., 33 U.S.C.
                1251(a)(2) (``[I]t is the national goal that wherever attainable, an
                interim goal of water quality which provides for the protection and
                propagation of fish, shellfish, and wildlife and provides for
                recreation in and on the water be achieved''), 1254(b)(6) (providing
                that the Administrator shall collect ``basic data on chemical,
                physical, and biological effects of varying water quality''),
                1311(b)(1)(C) (requiring permits to have limits as stringent as
                necessary to meet water quality standards), 1313(c) (providing that
                water quality standards ``shall be such as to protect the public health
                or welfare, enhance the quality of water and serve the purposes of this
                [Act]''). And Congress was clear that ``[t]he development of
                information which describes the relationship of pollutants to water
                quality is essential for carrying out the objective of the Act.'' S.
                Rep. No. 92-414 (1972), as reprinted in 1972 U.S.C.C.A.N. 3668, 3716.
                See also id. at 3717 (``Water quality is intended to refer to the
                biological, chemical and physical parameters of aquatic ecosystems, and
                is intended to include reference to key species, natural temperature
                and current flow patterns, and other characteristics which help
                describe ecosystem integrity. . . . The criteria will allow the
                translation of the narrative of the general objective of the Act to
                specific and precise parameters.''); id. at 3742 (``The Committee has
                added a definition of pollution to further refine the concept of water
                quality measured by the natural chemical, physical and biological
                integrity.''). As the Sixth Circuit explained shortly after the 1972
                enactment of the Clean Water Act: ``It would, of course, make a mockery
                of [Congress's] powers if its authority to control pollution was
                limited to the bed of the navigable stream itself. The tributaries
                which join to form the river could then be used as open sewers as far
                as federal regulation was concerned. The navigable part of the river
                could become a mere conduit for upstream waste.'' United States v.
                Ashland Oil & Transp. Co., 504 F.2d 1317, 1326 (6th Cir. 1974).
                 To be clear, the agencies do not interpret the objective of the
                Clean Water Act to be the only factor relevant to determining the scope
                of the Act. Rather, in light of the precise definitional language of
                the definitions in the Act, the importance of water quality to the
                statute as a whole, and Maui and other Supreme Court decisions
                affirming that consideration of the objective of the Act is important
                in defining the scope of the Act, the agencies conclude that
                consideration of the objective of the Act for purposes of a rule
                defining ``waters of the United States'' must include substantive
                consideration of the effects of a revised definition on the integrity
                of the nation's waters. As discussed further below, the proposed rule
                properly considers and advances the objective of the Act because it
                focuses on the effects of upstream waters including wetlands on
                traditional navigable waters, interstate waters, and the territorial
                seas, and is supported by the best available science on those water
                quality effects.
                b. The Proposed Rule Builds Upon the 1986 Regulations, Which Were
                Designed To Advance the Objective of the Act
                 The 1986 regulations--which are substantially the same as the 1977
                regulations--represented the agencies' interpretation of the Clean
                Water Act in light of its objective and their scientific knowledge
                about aquatic ecosystems. The 1986 regulations were designed to advance
                the objective of the Act and are thus a reasonable foundation upon
                which to build the proposed rule. In this proposed rule, the agencies
                are exercising their discretionary authority to interpret ``waters of
                the United States'' to mean the waters defined by the familiar 1986
                regulations, with amendments to reflect the agencies' interpretation of
                the statutory limits on the scope of the ``waters of the United
                States'' informed by Supreme Court decisions and the scientific record.
                 The best available science as discussed below confirms that the
                1986 regulations remain a reasonable foundation for a definition of
                ``waters of the United States'' that furthers the water quality
                objective of the Clean Water Act. See Technical Support Document. This
                section describes the agencies' historic rationale for the 1986
                regulations and its regulatory categories
                [[Page 69389]]
                and describes the latest science that supports the conclusion that the
                categories of waters identified in the 1986 regulations, such as
                tributaries, adjacent wetlands, and ``other waters,'' provide functions
                that restore and maintain the chemical, physical, and biological
                integrity of traditional navigable waters, interstate waters, and the
                territorial seas.
                 The agencies' historic regulations, which became the 1986
                regulations, were based on the agencies' scientific and technical
                judgment about which waters needed to be protected to restore and
                maintain the chemical, physical, and biological integrity of
                traditional navigable waters, interstate waters, and the territorial
                seas. For more than 40 years, EPA and the Corps recognized the need to
                protect ``the many tributary streams that feed into the tidal and
                commercially navigable waters . . . since the destruction and/or
                degradation of the physical, chemical, and biological integrity of each
                of these waters is threatened by the unregulated discharge of dredged
                or fill material.'' 42 FR 37121, 37123. The agencies further recognized
                that the nation's wetlands are ``a unique, valuable, irreplaceable
                water resource. . . . Such areas moderate extremes in waterflow, aid in
                the natural purification of water, and maintain and recharge the ground
                water resource.'' EPA, Protection of Nation's Wetlands: Policy
                Statement, 38 FR 10834 (May 2, 1973). In Riverside Bayview, the Supreme
                Court acknowledged that the agencies were interpreting the Act
                consistent with its objective and based on their scientific expertise:
                 In view of the breadth of federal regulatory authority
                contemplated by the Act itself and the inherent difficulties of
                defining precise bounds to regulable waters, the Corps' ecological
                judgment about the relationship between waters and their adjacent
                wetlands provides an adequate basis for a legal judgment that
                adjacent wetlands may be defined as waters under the Act.
                474 U.S. at 134.
                 As the Corps stated in promulgating the 1977 definition, ``[t]he
                regulation of activities that cause water pollution cannot rely on . .
                . artificial lines, however, but must focus on all waters that together
                form the entire aquatic system. Water moves in hydrologic cycles, and
                the pollution of . . . part of the aquatic system . . . will affect the
                water quality of the other waters within that aquatic system.'' 42 FR
                37128. Thus, the proposed rule includes the categories long identified
                by the agencies as affecting the water quality of traditional navigable
                waters, interstate waters, and the territorial seas, including
                tributaries, adjacent wetlands, impoundments, and ``other waters.''
                 For example, the agencies have long construed the Act to include
                tributaries as ``waters of the United States.'' The Corps explained in
                1977 that its regulations necessarily encompassed ``the many tributary
                streams that feed into the tidal and commercially navigable waters''
                because ``the destruction and/or degradation of the physical, chemical,
                and biological integrity of each of these waters is threatened by the
                unregulated discharge of dredged or fill material.'' Id. at 37123.
                 Construing ``waters of the United States'' to include tributaries
                of traditional navigable waters, interstate waters, the territorial
                seas, and impoundments of ``waters of the United States'' is consistent
                with the discussion of tributaries in the Act's legislative history.
                The Senate Report accompanying the 1972 Act states that ``navigable
                waters'' means ``the navigable waters of the United States, portions
                thereof, tributaries thereof, and includes the territorial seas and the
                Great Lakes.'' S. Rep. No. 92414, at 77 (1971), as reprinted in 1972
                U.S.C.C.A.N. 3668, 3742 (emphasis added). Furthermore, Congress
                recognized that Clean Water Act jurisdiction must extend broadly
                because ``[w]ater moves in hydrologic cycles and it is essential that
                [the] discharge of pollutants be controlled at the source.'' Id.
                Congress thus restated that ``reference to the control requirements
                must be made to the navigable waters, portions thereof, and their
                tributaries.'' Id. at 3743 (emphasis added).
                 As discussed below and further in the Technical Support Document,
                the best available science supports the 1986 regulations' conclusions
                about the importance of tributaries to the water quality of downstream
                foundational waters: Tributaries provide natural flood control,
                recharge groundwater, trap sediment, store and transform pollutants
                from fertilizers, decrease high levels of chemical contaminants,
                recycle nutrients, create and maintain biological diversity, and
                sustain the biological productivity of downstream rivers, lakes, and
                estuaries.
                 With the 1986 regulations, the agencies determined that wetlands
                adjacent to navigable waters generally play a key role in protecting
                and enhancing water quality: ``Water moves in hydrologic cycles, and
                the pollution of this part of the aquatic system, regardless of whether
                it is above or below an ordinary high water mark, or mean high tide
                line, will affect the water quality of the other waters within that
                aquatic system. For this reason, the landward limit of Federal
                jurisdiction under Section 404 must include any adjacent wetlands that
                form the border of or are in reasonable proximity to other waters of
                the United States, as these wetlands are part of this aquatic system.''
                42 FR 37128; see also 38 FR 10834.
                 In Riverside Bayview, the Supreme Court deferred to the agencies'
                judgment that adjacent wetlands provide valuable functions for
                downstream waters:
                [T]he Corps has concluded that wetlands may serve to filter and
                purify water draining into adjacent bodies of water and to slow the
                flow of surface runoff into lakes, rivers, and streams and thus
                prevent flooding and erosion. In addition, adjacent wetlands may
                ``serve significant natural biological functions, including food
                chain production, general habitat, and nesting, spawning, rearing
                and resting sites for aquatic . . . species.'' . . . [W]e cannot say
                that the Corps' judgment on these matters is unreasonable . . . .
                474 U.S. at 134-35 (citations omitted). The Supreme Court then
                unanimously held 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.'' Id. at
                135.
                 As discussed below and further in the Technical Support Document,
                the best available science supports the 1986 regulations' conclusions
                about the functions provided by adjacent wetlands to downstream
                traditional navigable waters, interstate waters, and the territorial
                seas, namely that adjacent wetlands provide valuable flood control and
                water quality functions including interruption and delay of the
                transport of water-borne contaminants over long distances, retention of
                sediment, prevention and mitigation of drinking water contamination,
                and assurance of drinking water supply.
                 The 1986 regulations also included ``other waters'' based on their
                effects on water quality and their effects on interstate commerce. 42
                FR 37128. As discussed below and further in section IV.D of the
                Technical Support Document, the best available science also shows that
                ``other waters''--such as depressional wetlands, open waters, and
                peatlands--can provide important hydrologic (e.g., flood control),
                water quality, and habitat functions which vary as a result of the
                diverse settings in which they exist across the country and which can
                have downstream effects on larger rivers, lakes, and estuaries,
                particularly when considered collectively with other non-floodplain
                wetlands on the landscape. The
                [[Page 69390]]
                functions that ``other waters'' provide include storage of floodwater,
                recharge of ground water that sustains river baseflow, retention and
                transformation of nutrients, metals, and pesticides, export of
                organisms to downstream waters, and habitats needed for aquatic and
                semi-aquatic species that also utilize streams.
                 While the 1986 regulations are a reasonable foundation upon which
                to build the proposed rule, the agencies are exercising their
                discretionary authority to interpret ``waters of the United States'' to
                mean the waters defined by the familiar 1986 regulations, with
                amendments to reflect the agencies' interpretation of the statutory
                limits on the scope of the ``waters of the United States'' informed by
                Supreme Court decisions as discussed in section V.A.3 of this preamble.
                c. The Proposed Rule Properly Considers the Objective by the Act
                Because It Is Informed by the Best Available Science on Water Quality
                 As noted above, the agencies propose to interpret the term ``waters
                of the United States'' to include: Traditional navigable waters,
                interstate waters, and the territorial seas, and their adjacent
                wetlands; most impoundments of ``waters of the United States'';
                tributaries to traditional navigable waters, interstate waters, the
                territorial seas, and impoundments, that meet either the relatively
                permanent standard or the significant nexus standard; wetlands adjacent
                to impoundments and tributaries, that meet either the relatively
                permanent standard or the significant nexus standard; and ``other
                waters'' that meet either the relatively permanent standard or the
                significant nexus standard. The proposal is supported by the best
                available science on the functions provided by upstream waters,
                including wetlands, that are important for the chemical, physical, and
                biological integrity of foundational waters. The agencies' proposal is
                supported by a wealth of scientific knowledge. The scientific
                literature extensively illustrates the effects tributaries, wetlands
                adjacent to impoundments and tributaries, and ``other waters'' can and
                do have on the integrity of downstream traditional navigable waters,
                interstate waters, and the territorial seas. The relevant science on
                the relationship and downstream effects of streams, wetlands, and open
                waters has advanced considerably in recent years, and confirms the
                agencies' longstanding view that these waters can be subject to
                jurisdiction. A comprehensive report prepared by EPA's Office of
                Research and Development entitled ``Connectivity of Streams and
                Wetlands to Downstream Waters: A Review and Synthesis of the Scientific
                Evidence'' \23\ (hereafter the Science Report) in 2015 synthesized the
                peer-reviewed science. Since the release of the Science Report,
                additional published peer-reviewed scientific literature has
                strengthened and supplemented the report's conclusions. The agencies
                have summarized and provided an update on more recent literature and
                scientific support for this section in the Technical Support Document
                section II.
                ---------------------------------------------------------------------------
                 \23\ U.S. Environmental Protection Agency, Connectivity of
                Streams and Wetlands to Downstream Waters: A Review and Synthesis of
                the Scientific Evidence (Final Report), EPA/600/R-14/475F (2015),
                available at https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=296414.
                ---------------------------------------------------------------------------
                 Again, in the proposed rule, the agencies are not including all
                tributaries, adjacent wetlands, and ``other waters'' as jurisdictional
                waters. Rather, the agencies are concluding that proposing these
                longstanding, familiar categories of waters as subject to the
                relatively permanent or significant nexus jurisdictional standards is
                consistent with the best available science because waters in these
                categories can have significant effects on downstream foundational
                waters, and are therefore proposing to restore them from the 1986
                regulations. The agencies are also proposing to add the relatively
                permanent and significant nexus standards based on their conclusion
                that together those standards are consistent with the statutory text,
                advance the objective and policies of the Act, and are supported by the
                scientific record. Indeed, the agencies are not reaching any
                conclusions, categorical or otherwise, about which tributaries,
                adjacent wetlands (other than those adjacent to traditional navigable
                waters, interstate waters, or the territorial seas), or ``other
                waters'' meet either the relatively permanent or the significant nexus
                standard. Instead, the proposal enables the agencies to make science-
                informed determinations of whether or not a water that falls within
                these categories meets either jurisdictional standard and is therefore
                a ``water of the United States,'' on a case-specific basis.
                 The agencies also reiterate their previous conclusion that
                significant nexus is not a purely scientific determination. 80 FR
                37054, 37060 (June 29, 2015). As the agencies charged with interpreting
                the statute, EPA and the Corps must develop the outer bounds of the
                scope of the Clean Water Act and science does not provide bright line
                boundaries with respect to where ``water ends'' for purposes of the
                Clean Water Act. Riverside Bayview, 474 U.S. at 132-33. This section
                summarizes the best available science in support of the longstanding
                categories of the 1986 regulation, and in support of the proposed rule
                and the agencies' conclusion that the proposal advances the objective
                of the Clean Water Act. This section reflects the scientific consensus
                on the strength of the effects that upstream tributaries, adjacent
                wetlands, and ``other waters'' can and do have on downstream
                foundational waters. However, a significant nexus determination
                requires legal, technical, and policy judgment, as well as scientific
                considerations, for example, to assess the significance of any effects.
                Section V.D of this preamble discusses the agencies' approaches to
                making case-specific relatively permanent and significant nexus
                determinations under the proposed rule.
                 Thus, while the agencies are not proposing to establish that any
                tributaries, adjacent wetlands (other than those wetlands adjacent to
                traditional navigable waters, interstate waters, and the territorial
                seas), or ``other waters'' are jurisdictional without the need for
                further assessment, they are proposing a rule that, based on the
                scientific record, identifies those categories of waters as subject to
                jurisdiction under the Clean Water Act under either the relatively
                permanent or significant nexus standard.
                i. Tributaries Can Provide Functions That Restore and Maintain the
                Chemical, Physical, and Biological Integrity of Downstream Traditional
                Navigable Waters, Interstate Waters, and the Territorial Seas
                 Tributaries play an important role in the transport of water,
                sediments, organic matter, nutrients, and organisms to downstream
                foundational waters. See Technical Support Document section IV.A.
                Tributaries slow and attenuate floodwaters; provide functions that help
                maintain water quality; trap and transport sediments; transport, store
                and modify pollutants; and sustain the biological productivity of
                downstream mainstem waters. Tributaries can provide these functions
                whether they are natural, modified, or constructed and whether they are
                perennial, intermittent, or ephemeral.
                 All tributary streams, including perennial, intermittent, and
                ephemeral streams, are chemically, physically, and biologically
                connected to larger downstream waters via channels and associated
                alluvial deposits where water and other materials are concentrated,
                mixed, transformed, and transported. Streams, even where seasonally
                dry, are
                [[Page 69391]]
                the dominant source of water in most rivers, rather than direct
                precipitation or groundwater input to mainstem river segments. Within
                stream and river networks, headwater streams make up most of the total
                channel length. The smallest streams represent an estimated three-
                quarters of the total length of stream and river channels in the United
                States.\24\ Because of their abundance and location in the watershed,
                small streams offer the greatest opportunity for exchange between the
                water and the terrestrial environment.
                ---------------------------------------------------------------------------
                 \24\ The actual proportion may be much higher because this
                estimate is based on the stream networks shown on the U.S.
                Geological Survey (USGS) National Hydrography Dataset, which does
                not show all headwater streams.
                ---------------------------------------------------------------------------
                 In addition, compared with the humid regions of the country, stream
                and river networks in arid regions have a higher proportion of channels
                that flow ephemerally or intermittently. For example, in Arizona, most
                of the stream channels--96% by length--are classified as ephemeral or
                intermittent. The functions that streams provide to benefit downstream
                waters occur even when streams flow less frequently, such as
                intermittent or ephemeral streams. For example, ephemeral headwater
                streams shape larger downstream river channels by accumulating and
                gradually or episodically releasing stored materials such as sediment
                and large woody debris.\25\ Due to the episodic nature of flow in
                ephemeral and intermittent channels, sediment and organic matter can be
                deposited some distance downstream in the arid Southwest in particular,
                and then moved farther downstream by subsequent precipitation events.
                Over time, sediment and organic matter continue to move downstream and
                influence larger downstream waters. These materials help structure
                downstream river channels by slowing the flow of water through channels
                and providing substrate and habitat for aquatic organisms.
                ---------------------------------------------------------------------------
                 \25\ Videos of ephemeral streams flowing after rain events in
                the Southwest highlight how effective ephemeral streams can be in
                transporting woody debris (e.g., tree branches) and sediment
                downstream during the rainy season. See, e.g., U.S. Department of
                Agriculture, Agricultural Research Service, Multiflume Runoff Event
                August 1, 1990, https://www.tucson.ars.ag.gov/unit/WGWebcam/WalnutGulchWebcam.htm; U.S. Geological Survey, Post-fire Flash Flood
                in Coronado National Memorial, Arizona (August 25, 2011), https://www.youtube.com/watch?v=qJ8JxBZt6Ws; Santa Clara Pueblo Fire/Rescue/
                EMS Volunteer Department, Greg Lonewolf, #4 Santa Clara Pueblo Flash
                Flood Event 01 Sept 2013 (April 14, 2017), https://www.youtube.com/watch?v=nKOQzkRi4BQ; Rankin Studio, Amazing Flash Flood/Debris Flow
                Southern Utah HD (July 19, 2019), https://www.youtube.com/watch?v=_yCnQuILmsM.
                ---------------------------------------------------------------------------
                 Stream and wetland ecosystems also process natural and human
                sources of nutrients, such as those found in leaves that fall into
                streams and those that may flow into creeks from agricultural fields.
                Some of this processing converts the nutrients into more biologically
                useful forms. Other aspects of the processing store nutrients, thereby
                allowing their slow and steady release and preventing the kind of
                short-term glut of nutrients that can cause algal blooms in downstream
                rivers or lakes. Small streams and their associated wetlands play a key
                role in both storing and modifying potential pollutants, ranging from
                chemical fertilizers to rotting salmon carcasses, in ways that maintain
                downstream water quality. Inorganic nitrogen and phosphorus, the main
                chemicals in agricultural fertilizers, are essential nutrients not just
                for plants, but for all living organisms. However, in excess or in the
                wrong proportions, these chemicals can harm natural systems and humans.
                Larger rivers process excess nutrients much more slowly than smaller
                streams. Loss of nutrient retention capacity in headwater streams is
                known to cause downstream water bodies to contain higher concentrations
                and loads of nitrogen and phosphorus. In freshwater ecosystems,
                eutrophication, the enriching of waters by excess nitrogen and
                phosphorus, reduces water quality in streams, lakes, estuaries, and
                other downstream water bodies. One obvious result of eutrophication is
                the excessive growth of algae. Too much algae clouds previously clear
                streams, such as those favored by trout. Algal blooms not only reduce
                water column visibility, but the microbial decay of algal blooms
                reduces the amount of oxygen dissolved in the water, sometimes to a
                degree that causes fish kills. Fish are not the only organisms harmed
                by eutrophication: Some of the algae species that grow in eutrophic
                waters generate tastes and odors or are toxic--a clear problem for
                stream systems, reservoirs, and lakes that supply drinking water for
                municipalities or that are used for swimming and other contact-
                recreational purposes. In addition, increased nitrogen and phosphorus
                and associated algal blooms can injure people and animals. Algal blooms
                can also lead to beach closures. In addition to causing algal blooms,
                eutrophication changes the natural community composition of aquatic
                ecosystems by altering environmental conditions.
                 Recycling organic carbon contained in dead plants and animals is
                another crucial function provided by headwater streams and wetlands.
                Ecological processes that transform inorganic carbon into organic
                carbon and recycle organic carbon are the basis for every food web on
                the planet. In freshwater ecosystems, much of the recycling happens in
                small streams and wetlands, where microorganisms transform everything
                from leaf litter and downed logs to dead salamanders into food for
                other organisms in the aquatic food web, including salmon. Like
                nitrogen and phosphorus, carbon is essential to life but can be harmful
                to freshwater ecosystems if it is present in excess or in the wrong
                chemical form. If all organic material received by headwater streams
                and wetlands went directly downstream, the glut of decomposing material
                could deplete oxygen in downstream rivers, thereby damaging and even
                killing fish and other aquatic life. The ability of headwater stream
                ecosystems to transform organic matter into more usable forms helps
                maintain healthy downstream ecosystems.
                 Microorganisms in headwater stream systems use material such as
                leaf litter and other decomposing material for food and, in turn,
                become food for other organisms. For example, fungi that grow on leaf
                litter become nutritious food for invertebrates that make their homes
                on the bottom of a stream, including mayflies, stoneflies, and caddis
                flies. These animals provide food for larger animals, including birds
                such as flycatchers and fish such as trout. The health and productivity
                of downstream traditional navigable waters, interstate waters, or the
                territorial seas depend in part on processed organic carbon delivered
                by upstream headwater systems.
                 To be clear, the agencies recognize that SWANCC held that the use
                of ``isolated'' non-navigable intrastate ponds by migratory birds was
                not by itself a sufficient basis for the exercise of federal regulatory
                authority under the Clean Water Act. Consideration of biological
                functions does not constitute an assertion of jurisdiction over a water
                based solely on its use by migratory birds; rather, the agencies would
                consider biological functions for purposes of significant nexus
                determinations under the proposed rule only to the extent that the
                functions provided by tributaries, adjacent wetlands, and ``other
                waters'' significantly affect the biological integrity of the
                downstream traditional navigable waters, interstate waters, or the
                territorial seas. For example, to protect Pacific and Atlantic salmon
                in traditional navigable waters (and their associated commercial and
                recreational fishing industries), headwater streams must be protected
                because Pacific and
                [[Page 69392]]
                Atlantic salmon require both freshwater and marine habitats over their
                life cycles and therefore migrate along river networks, providing one
                of the clearest illustrations of biological connectivity. Many Pacific
                salmon species spawn in headwater streams, where their young grow for a
                year or more before migrating downstream, live their adult life stages
                in the ocean, and then migrate back upstream to spawn. Even where they
                do not provide direct habitat for salmon themselves, ephemeral streams
                may contribute to the habitat needs of salmon by supplying sources of
                cold water that these species need to survive (i.e., by providing
                appropriate physical conditions for cold water upwelling to occur at
                downstream confluences), transporting sediment that supports fish
                habitat downstream, and providing and transporting food for juveniles
                and adults downstream. These species thereby create a biological
                connection along the entire length of the river network and
                functionally help to maintain the biological integrity of the
                downstream traditional navigable water. Many other species of
                anadromous fish--that is fish that are born in freshwater, spend most
                of their lives in saltwater, and return to freshwater to lay eggs--as
                well as species of freshwater fish like rainbow trout and brook trout
                also require small headwater streams to carry out life cycle functions.
                 Based on the importance of the functions that can be provided by
                tributaries to foundational waters, the agencies' proposal to interpret
                the Clean Water Act to protect tributaries where those tributaries meet
                either the relatively permanent standard or the significant nexus
                standard reflects proper consideration of the objective of the Act and
                the best available science.
                ii. Adjacent Wetlands Provide Functions That Restore and Maintain the
                Chemical, Physical, and Biological Integrity of Downstream Traditional
                Navigable Waters, Interstate Waters, and the Territorial Seas
                 Adjacent wetlands provide valuable flood control and water quality
                functions that affect the chemical, physical, and biological integrity
                of downstream foundational waters including interruption and delay of
                the transport of water-borne contaminants over long distances;
                retention of sediment; retention and slow release of flood waters; and
                prevention and mitigation of drinking water contamination and assurance
                of drinking water supply. See Technical Support Document section IV.B.
                 Because adjacent wetlands retain sediment and augment streamflow
                via the gradual release of groundwater or water flowing just beneath
                the solid surface, wetland loss correlates with increased need for
                dredging and unpredictability of adequate streamflow for navigation.
                The Supreme Court has recognized the importance of the physical
                integrity of upstream tributaries in overcoming sedimentation hazards
                to navigation. United States v. Rio Grande Dam Irrigation Co., 174 U.S.
                690 (1899). Headwater wetlands are located where erosion risk is
                highest and are therefore best suited to recapture and stabilize
                manageable amounts of sediment that might enter traditional navigable
                waters, interstate waters, or the territorial seas. Adjacent wetlands
                naturally serve to recapture and stabilize sediment carried by streams
                and rivers in times when flood flow distributes water across a
                floodplain.
                 Adjacent wetlands affect the integrity of downstream waters by
                retaining stormwater and slowly releasing floodwaters that could
                otherwise negatively affect the condition or function of downstream
                waters. The filling or draining of wetlands, including those that are
                close to the stream network, reduces water storage capacity in a
                watershed and causes runoff from rainstorms to overwhelm the remaining
                available water conveyance system. The resulting stream erosion and
                channel downcutting quickly drains the watershed as surface water
                leaves via incised (deeper) channels. Disconnecting the incised channel
                from the wetlands leads to more downstream flooding. As the adjacent
                wetlands remain disconnected, riparian vegetation and wetland functions
                are reduced. Because less water is available in groundwater and
                wetlands for slow release to augment streamflow during dry periods, the
                filling or draining of wetlands can make the timing and extent of
                navigability on some waterways less predictable during dry periods.
                Therefore, the filling or draining of adjacent wetlands, including
                headwater wetlands, can interfere with the ability to maintain
                navigability on the nation's rivers and harbors and can lead to
                flooding in larger downstream waters.
                 The loss of wetlands adjacent to tributaries of navigable waters,
                interstate waters, and the territorial seas can also result in notable
                reductions in drinking water supply and quality. Over 225 million
                people are served by nearly 15,000 public water systems using surface
                water such as streams, rivers, lakes, tributaries, and surface-water
                storage impoundments as a primary source of water. Though drinking
                water supplied through public water supplies is regulated by the Safe
                Drinking Water Act, many water suppliers also rely on source water
                protection efforts, as the quality of the drinking water source is
                dependent on the protection of its upstream waters. Discharge of
                agricultural, industrial, sanitary, or other waste into any surface
                water may pose a public health risk downstream. For example, excessive
                upstream discharge may overwhelm a public water system filtration unit,
                allowing microbial pathogens into the drinking water system. EPA's
                Science Advisory Board cited drinking water contamination by pathogens
                as one of the most important environmental risks. Drinking water
                treatment to address microbial pathogens has little effect on many
                toxic chemicals, metals, and pesticides discharged into streams,
                drainage ditches, canals, or other surface waters. Conserving wetlands
                in source water protection areas can help protect water quality,
                recharge aquifers, and maintain surface water flow during dry periods.
                 Adjacent wetlands have an important role in improving source water
                quality, due to their strategic location as buffers for other water
                bodies and their filtration of surface water. Detention of water and
                its associated constituents by wetlands allows the biochemical uptake
                and/or breakdown of contaminants, and the destruction of pathogens. A
                wide and dense distribution of adjacent wetlands protects and mitigates
                against contaminant discharges. The water detention capacity of
                adjacent wetlands also allows for the storage and gradual release of
                surface waters that may supply public water system intakes during times
                of drought. In either case, this detention substantially improves both
                the supply and quality of drinking water. For example, wetlands
                conservation is a crucial feature of the low-cost New York City
                municipal water system, which provides high-quality drinking water to
                millions of people through watershed protection, including of adjacent
                wetlands, of its source waters rather than extensive treatment.
                 Based on the importance of the functions that are provided by
                adjacent wetlands to foundational waters, the agencies' proposal to
                interpret the Clean Water Act to protect adjacent wetlands where those
                adjacent wetlands meet either the relatively permanent standard or the
                significant nexus standard reflects proper consideration of the
                objective of the Act and the best available science.
                [[Page 69393]]
                iii. ``Other waters'' Can Provide Functions That Restore and Maintain
                the Chemical, Physical, and Biological Integrity of Downstream
                Traditional Navigable Waters, Interstate Waters, and the Territorial
                Seas
                 ``Other waters''--examples of which include, but are not limited
                to, intrastate lakes, wetlands, prairie potholes, playa lakes, streams
                that are not tributaries, and natural ponds--can provide important
                functions which affect the chemical, physical, and biological integrity
                of downstream foundational waters. See Technical Support Document
                section IV.D. These functions are particularly valuable when considered
                cumulatively across the landscape or across different watershed/sub-
                watershed scales and are similar to the functions that adjacent
                wetlands provide, including water storage to control streamflow and
                mitigate downstream flooding; interruption and delay of the transport
                of water-borne pollutants (such as excess nutrients and contaminants)
                over long distances; and retention of sediment. These functions can be
                important to the physical integrity of downstream foundational waters.
                For non-floodplain wetlands and open waters lacking a channelized
                surface or regular shallow subsurface connection, generalizations from
                the available literature about their specific effects on downstream
                waters are difficult because information on both function and
                connectivity is needed, and thus case-specific analysis of their
                effects on downstream waters is appropriate from both a scientific and
                policy perspective.
                 ``Other waters'' individually span the gradient of connectivity
                identified in the Science Report; they can be open waters located in
                the riparian area or floodplain of traditional navigable waters,
                interstate waters, and the territorial seas (e.g., oxbow lakes) and
                otherwise be physically proximate to the stream network (similar to
                adjacent wetlands) or they can be open waters or wetlands that are
                fairly distant from the network. They can be connected to downstream
                foundational waters via confined surface or subsurface connections
                (including channels, pipes, and culverts), unconfined surface
                connections, shallow subsurface connections, deeper groundwater
                connections, biological connections, or spillage. They can also provide
                additional functions such as storage and mitigation of peak flows,
                natural filtration by biochemical uptake and/or breakdown of
                contaminants, and in some locations, high volume aquifer recharge that
                contributes to the baseflow in downstream waters. The strength of
                functions provided by ``other waters'' on downstream waters will vary
                depending on the type and degree of connection (i.e.., from highly
                connected to highly isolated) to downstream waters and landscape
                features such as proximity to stream networks and to ``other waters''
                with similar characteristics that function as a group to influence
                jurisdictional downstream waters.
                 Since the publication of the Science Report in 2015, the published
                literature has expanded scientific understanding and quantification of
                functions that ``other waters'' perform that affect the integrity of
                traditional navigable waters, interstate waters, and the territorial
                seas, particularly in the aggregate. The more recent literature (i.e.,
                2014-present, as some literature from 2014 and 2015 may not have been
                included in the Science Report) has determined that non-floodplain
                wetlands can have demonstrable hydrologic and biogeochemical downstream
                effects, such as decreasing peak flows, maintaining baseflows, and
                performing nitrate removal, particularly when considered cumulatively.
                 Oxbow lakes and other lakes and ponds that are in close proximity
                to the stream network, located within floodplain or riparian areas, or
                that are connected via surface and shallow subsurface hydrology to the
                stream network or to other ``waters of the United States'' also perform
                critical chemical, physical, and biological functions that affect
                downstream foundational waters. Like adjacent wetlands, these waters
                individually and collectively affect the integrity of downstream waters
                by acting as sinks that retain floodwaters, sediments, nutrients, and
                contaminants that could otherwise negatively impact the condition or
                function of downstream waters. They also provide important habitat for
                aquatic species to forage, breed, and rest.
                 Some ``other waters'' are wetlands that are located too far from
                other jurisdictional waters to be considered ``adjacent.'' The specific
                distance may vary based on the characteristics of the aquatic resources
                being evaluated, but they are often located outside of the riparian
                area or floodplain, lack a confined surface or shallow subsurface
                hydrologic connection to jurisdictional waters, or exceed the minimum
                distances necessary for aquatic species that cannot disperse overland
                to utilize both the subject waters and the waters in the broader
                tributary network. Some ``other waters'' may be too removed from the
                stream network or from jurisdictional waters to have significant
                effects on downstream traditional navigable waters, interstate waters,
                or the territorial seas. However, particularly when considered in the
                aggregate, some ``other waters'' can, in certain circumstances, have
                strong chemical, physical, and biological connections to and effects on
                foundational waters. Sometimes it is their relative isolation from the
                stream network (e.g., lack of a hydrologic surface connection) that
                contributes to the important effect that they have downstream; for
                example, depressional non-floodplain wetlands lacking surface outlets
                can function individually and cumulatively to retain and transform
                nutrients, retain sediment, provide habitat, and reduce or attenuate
                downstream flooding, depending on site-specific conditions such as
                landscape characteristics (e.g., slope of the terrain, permeability of
                the soils).
                 Based on the functions that can be provided by ``other waters'' to
                traditional navigable waters, interstate waters, and the territorial
                seas, the agencies' proposal to assess ``other waters'' to determine
                whether they meet either the relatively permanent standard or the
                significant nexus standard reflects proper consideration of the
                objective of the Act and the best available science.
                 The agencies' use of the best available science to interpret the
                scope of ``waters of the United States'' is a change from the NWPR. In
                the NWPR's preamble, the agencies stated: ``While science informs the
                agencies' interpretation'' of the phrase ``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.''
                85 FR 22271, April 21, 2020; see also id. at 22314 (``the line between
                Federal and State waters is a legal distinction, not a scientific
                one''). In this proposal, the agencies agree that science alone cannot
                dictate where to draw the line defining ``waters of the United
                States.'' But science is critical to attaining Congress's objective to
                restore and maintain the chemical, physical, and biological integrity
                of the nation's waters: Only by relying upon scientific principles to
                understand the way waters affect one another can the agencies know
                whether they are achieving that objective. Drawing the line without
                regard to science risks nullifying Congress's objective altogether. And
                because the agencies believe that the definition of ``waters of the
                United States'' should advance the objective of the Act and that
                objective is focused on restoring and maintaining water quality, see
                section V.A.2 of this preamble, the best available science is of far
                more importance to the agencies' proposed
                [[Page 69394]]
                rule than it was in the NWPR. Moreover, the agencies have concluded
                that the NWPR was not informed by the science, but rather was
                inconsistent with the best available science in substantially important
                ways. See section V.B.3 of this preamble.
                iv. The Significant Nexus Standard Allows for Consideration of the
                Effects of Climate Change on Water Resources Consistent With the Best
                Available Science
                 The significant nexus standard allows for the agencies to consider
                a changing climate when evaluating if upstream waters significantly
                affect foundational waters. This is because the significant nexus
                standard is based on the science of the strength of the effects that
                upstream tributaries, adjacent wetlands, and ``other waters'' can and
                do have on downstream foundational waters, and so implementation of the
                standard can adapt to changing climatic conditions. For example, a lake
                that dries up from warming temperatures due to climate change and no
                longer has a surface hydrologic connection to downstream waters might
                become non-jurisdictional, whereas another lake that previously had
                limited surface hydrologic connectivity might have increased hydrologic
                connectivity with higher precipitation conditions under a changing
                climate.
                 In addition, the significant nexus standard allows the agencies to
                consider the functions of streams, wetlands, and open waters that
                support the resilience of the chemical, physical, or biological
                integrity of traditional navigable waters, interstate waters, or the
                territorial seas to climate change. For example, as more intense and
                frequent storms and other shifts in precipitation cause floods to
                increase in frequency and volume in some areas of the United States, a
                significant nexus determination can evaluate the strength of the effect
                of runoff storage in wetlands, open waters, and headwater tributaries
                in mitigating increased flood risk associated with climate change in
                downstream foundational waters. In addition, as drought leads to
                decreased baseflows in foundational waters in other areas of the
                country, the transmission of flows into alluvial or regional aquifer
                storage through tributaries and wetlands can mitigate for these climate
                change-related conditions, and those benefits to downstream traditional
                navigable waters or interstate waters can be assessed as part of a
                significant nexus analysis. Changes in flow in tributaries caused by
                climate change will also be relevant to the relatively permanent
                standard, but that standard may not allow the agencies to take into
                account the contribution of upstream waters to the resilience of the
                integrity of downstream waters.
                 As discussed in section V.C.10 of this preamble, the agencies
                believe that there are climate benefits that streams, wetlands, and
                open waters provide that are not related to restoring or maintaining
                the integrity of downstream traditional navigable waters, interstate
                waters, or the territorial seas, such as carbon sequestration. Those
                functions would not be considered under this rule because they are not
                directly related to the chemical, physical, and biological integrity of
                downstream waters. However, considering a changing climate when
                conducting jurisdictional decisions by considering on a case-by-case
                basis the functions of aquatic resources that contribute to the
                resilience of the integrity of downstream foundational waters to
                climate change is consistent with the policy and goals of the Clean
                Water Act, case law, and the policy goals of this administration as
                articulated in Executive Order 13990.
                3. The Proposed Rule Establishes Limitations That Together Are
                Consistent With the Statutory Text, Supported by the Scientific Record,
                and Informed by Relevant Supreme Court Decisions
                 In this proposed rule, the agencies are exercising their
                discretionary authority to interpret ``waters of the United States'' to
                mean the waters defined by the familiar 1986 regulations, with
                amendments to reflect the agencies' interpretation of the statutory
                limits on the scope of the ``waters of the United States'' informed by
                Supreme Court decisions. The proposed rule's relatively permanent and
                significant nexus limitations are based on the agencies' conclusion
                that together those standards are consistent with the statutory text,
                are supported by the scientific record, and appropriately consider the
                objective in section 101(a) of the Act and the policy in section
                101(b). Moreover, these fact-dependent, science-informed approaches to
                jurisdiction are not unique under the Clean Water Act.
                 At the outset, the agencies think it is useful to lay out the areas
                where the agencies agree with the statutory interpretation and case law
                laid out in the NWPR. The agencies agree that ``[b]y the time the 1972
                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,'' 85 FR 22263, April 21, 2020
                (citing Oklahoma ex rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508,
                523 (1941)), and that ``Congress had in mind a broader scope of waters
                subject to CWA jurisdiction than waters traditionally understood as
                navigable,'' id.; see also id. at 22267 (recognizing that ``[t]he
                plurality and Justice Kennedy both recognized the jurisdictional scope
                of the CWA is not restricted to traditional navigable waters'' in
                Rapanos). In fact, it would be impossible to achieve Congress's
                objective if the scope of authority were constrained to waters
                traditionally understood as navigable because those channels cannot be
                protected without protecting the tributaries that flow into them and
                wetlands adjacent to them. Cf. United States v. Ashland Oil & Transp.
                Co., 504 F.2d 1317, 1326 (6th Cir. 1974) (``It would, of course, make a
                mockery of [Congress's] powers if its authority to control pollution
                was limited to the bed of the navigable stream itself. The tributaries
                which join to form the river could then be used as open sewers as far
                as federal regulation was concerned. The navigable part of the river
                could become a mere conduit for upstream waste.''). The Supreme Court
                has explained both that the term ``navigable'' in the defined term
                ``navigable waters'' has ``limited import,'' Riverside Bayview, 474
                U.S. at 133, and also that by using the term ``navigable,'' ``Congress
                had in mind as its authority for enacting the CWA[ ] [i]ts 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. As the
                agencies did in the NWPR, the agencies interpret this to mean that the
                object of federal protection is foundational waters, and that
                jurisdiction encompasses (and is limited to) those tributaries,
                wetlands, and open waters that are necessary to protect the
                foundational waters.\26\
                ---------------------------------------------------------------------------
                 \26\ Unlike the NWPR, the agencies now interpret the
                foundational waters to include ``interstate waters.'' See section
                V.C.2 of this preamble.
                ---------------------------------------------------------------------------
                 The agencies also agree that ``there must be a limit to that
                authority and to what water is subject to federal jurisdiction,'' 85 FR
                22263, April 21, 2020, that where to draw that limit is ambiguous, and
                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,'' id. at 22264 (quoting Nat'l Cable & Telecomm. Ass'n
                v. Brand X
                [[Page 69395]]
                internet Servs., 545 U.S. 967, 982 (2005)). In determining that limit,
                the agencies generally continue to believe that the determination of
                jurisdiction with regard to wetlands adjacent to tributaries ``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'' and that the
                concept of a ``connectivity gradient'' is useful. Id. at 22267, 22271.
                Similarly, for tributaries, the agencies agree that ``contribution of
                flow to and connection'' matters. Id. at 22267. At bottom, the agencies
                agree that the Supreme Court has indicated that the limit should relate
                to the ``significant effects'' of or ``significant nexus'' between that
                water and traditional navigable waters, interstate waters, and the
                territorial seas, id at 22263-64 (discussing Supreme Court case law,
                although as explained in section V.A.3.a of this preamble, the NWPR in
                fact removed the significant nexus test without considering an
                alternative approach to protecting waters that significantly affect
                downstream traditional navigable waters). Finally, the agencies agree
                that the Supreme Court has ``call[ed] into question the agencies'
                authority to regulate nonnavigable, isolated, intrastate waters that
                lack a sufficient connection to traditional navigable waters,'' id. at
                22269, and this proposal would not assert jurisdiction over such
                waters.\27\
                ---------------------------------------------------------------------------
                 \27\ The NWPR criticized the agencies' prior practice as
                insufficiently attentive to the concerns raised by the Supreme Court
                in SWANCC regarding jurisdiction over the ``other waters'' category
                defined in (a)(3) of the regulatory definition that was at issue in
                SWANCC. Id. at 22264. This criticism is inaccurate. Cognizant of the
                Supreme Court's direction in SWANCC and to ensure that any assertion
                of authorities over (a)(3) waters is consistent with the Court's
                precedents, since SWANCC, the agencies have required that before
                exercising jurisdiction over an (a)(3) water field staff get
                approval from headquarters. 68 FR 1991 (January 15, 2003). As a
                practical matter, and as discussed in more detail below, section
                V.C.3 of this preamble, field staff have rarely, if ever, sought
                such approval and therefore the agencies have not asserted
                jurisdiction over (a)(3) waters. But (a)(3) waters can have
                significant effects on foundational waters and, when they do,
                jurisdiction is proper and would not implicate the constitutional
                concerns expressed by the Court in SWANCC for the reasons explained
                herein.
                ---------------------------------------------------------------------------
                a. The Relatively Permanent Standard and the Significant Nexus Standard
                Together Advance the Objective of the Act
                 The proposed rule's utilization of both the relatively permanent
                standard and the significant nexus standard gives effect to the Act's
                broad terms and environmentally protective aim as well as its
                limitations. See Rapanos, 547 U.S. at 767-69 (observing ``the evident
                breadth of congressional concern for protection of water quality and
                aquatic ecosystems'' and referring to the Act as ``a statute concerned
                with downstream water quality'') (Kennedy, J., concurring) (citations
                omitted); Riverside Bayview, 474 U.S. at 133 (``Congress chose to
                define the waters covered by the Act broadly.''). The agencies,
                however, are proposing that it is the significant nexus standard that
                advances the objective of the Act because it is linked to effects on
                downstream water quality while establishing a reasonable limitation on
                the scope of jurisdiction by requiring those links to be significant.
                The relatively permanent standard is administratively useful as an
                example of a subset of waters that will virtually always have the
                requisite nexus, but, on its own, is insufficiently protective to meet
                the objective of the Clean Water Act.
                 The agencies have consistently construed Rapanos to mean that a
                water is jurisdictional under the Clean Water Act if it meets either
                the relatively permanent standard or the significant nexus standard.
                The NWPR, however, interpreted the statute to primarily find waters
                jurisdictional only if they met the relatively permanent standard, as
                specifically interpreted in the NWPR. The NWPR argued that it reflected
                both the plurality and Kennedy opinions, which it characterized as
                having ``sufficient commonalities . . . to help instruct the agencies
                on where to draw the line between Federal and State waters.'' 85 FR
                22268, April 21, 2020. The opinions have important differences,
                however. Justice Kennedy looked to the existence of a significant nexus
                between waters at issue and downstream traditional navigable waters,
                whereas the plurality held that ``waters of the United States'' is
                limited to ``relatively permanent'' waters connected to traditional
                navigable waters, and wetlands with a ``continuous surface connection''
                with those waters. Rapanos, 547 U.S. at 742. Justice Kennedy rejected
                these two limitations in the plurality as ``without support in the
                language and purposes of the Act or in our cases interpreting it.'' Id.
                at 768; see also id. at 776 (``In sum the plurality's opinion is
                inconsistent with the Act's text, structure, and purpose.''). Yet the
                plurality's limitation of jurisdiction to ``relatively permanent
                waters'' and those with a ``continuous surface connection'' to those
                waters pervades the NWPR. See 85 FR 22338-39; 33 CFR 328.3(a), (c)(1),
                (c)(6), and (c)(12). The NWPR disregards the significant nexus
                standard, see generally 85 FR 22338-39; 33 CFR 328.3, and, in doing so,
                restricted the scope of the statute using limitations Justice Kennedy
                viewed as anathema to the purpose and text of the Clean Water Act.
                 The agencies propose to reject the NWPR's interpretation as
                inconsistent with the objective of the Clean Water Act, the science,
                and the case law, and instead to propose an interpretation whereby if a
                water meets either standard, it falls within the protections of the
                Clean Water Act. This section first discusses why the significant nexus
                test is consistent with the Act and the best available science; then
                explains why the relatively permanent standard is administratively
                useful, but limiting the scope of jurisdiction to waters meeting the
                relatively permanent standard is insufficient to meet the objective of
                the Clean Water Act; and finally, explains that fact-based standards
                for determining Clean Water Act jurisdiction are reasonable and not
                unique to the definition of ``waters of the United States.''
                i. The Significant Nexus Test Is Consistent With the Act and the Best
                Available Science
                 The significant nexus standard advances the objective of the Act
                because it is linked to effects on downstream water quality while
                establishing a reasonable limitation on the scope of jurisdiction. The
                significant nexus standard reasonably effectuates the text of 33 U.S.C.
                1362(7), which defines ``navigable waters.'' The requirement that a
                significant nexus exist between upstream waters, including wetlands and
                ``navigable waters in the traditional sense'' fulfills ``the need to
                give the term `navigable' some meaning.'' Rapanos, 547 U.S. at 779
                (Kennedy, J., concurring). With the significant nexus standard, the
                proposed rule is properly focused on protecting the foundational waters
                clearly protected by the Clean Water Act. The significant nexus is thus
                consistent with the text of the Act, with scientific principles and
                supported by the best available science, with the Act's legislative
                history, and with case law.
                 Congress was focused on water quality when it enacted the Clean
                Water Act and established its objective, as discussed in section V.A.2
                of this preamble. The significant nexus standard is derived from the
                objective of the Act and thus also focused on water quality and
                specifically focused on the water quality of the foundational waters.
                As described more fully in section V.A.2.c of this preamble, supra, the
                [[Page 69396]]
                significant nexus standard is consistent with scientific principles
                about the aquatic ecosystem: Upstream waters can significantly affect
                the chemical, physical, and biological integrity of downstream
                traditional navigable waters, interstate waters, and the territorial
                seas. Therefore, assessing the effects that waters have on downstream
                foundational waters when considered, alone or in combination with other
                similar waters in a region, is a reasonable means of identifying those
                waters necessary to protect in order to advance the objective of the
                Act.
                 A significant nexus analysis is consistent with the framework
                through which scientists assess a river system--examining how the
                components of the system (e.g., wetlands, tributaries), in the
                aggregate (in combination), in the region, contribute and connect to
                the river (significantly affect the chemical, physical, or biological
                integrity of foundational waters). Indeed, the significant nexus
                standard in the proposed rule reflects the type of analysis in the
                Science Report by describing the components of a river system and
                watershed; the types of physical, chemical, and biological connections
                that link those components; the factors that influence connectivity at
                various temporal and spatial scales; and methods for quantifying
                connectivity. The structure and function of rivers are highly dependent
                on the constituent materials stored in and transported through them.
                Most of these materials originate from either the upstream river
                network or other components of the river system and then are
                transported to the river by water movement or other mechanisms.
                Further, the significant nexus standard is supported by the Science
                Report's discussion of connectivity, a foundational concept in
                hydrology and freshwater ecology. See also Technical Support Document.
                 Connectivity is the degree to which components of a system are
                joined, or connected, by various transport mechanisms and is determined
                by the characteristics of both the physical landscape and the biota of
                the specific system. Connectivity serves to demonstrate the ``nexus''
                between upstream water bodies and the downstream traditional navigable
                water, interstate water, or the territorial sea and, while the
                scientific literature does not use the term ``significant'' in the same
                manner used by the Supreme Court, the literature does provide
                information on the strength of the effects on the chemical, physical,
                and biological functioning of the downstream water bodies that permits
                the agencies to judge when an effect is significant such that a water,
                alone or in combination, should be protected by the Clean Water Act in
                order to meet the objective of the Act. The Science Report presents
                evidence of connections for various categories of waters, evaluated
                singly or in combination, which affect downstream waters and the
                strength of those effects. The connections and mechanisms discussed in
                the Science Report include: Transport of physical materials and
                chemicals such as water, wood, sediment, nutrients, pesticides, and
                mercury; functions that jurisdictional adjacent waters perform, such as
                storing and cleansing water; and movement of organisms. Again, the
                significant nexus standard, under which waters are assessed alone or in
                combination for the functions they provide downstream, is consistent
                with the foundational scientific framework and concepts of hydrology.
                 The agencies' use of scientific principles to determine the scope
                of ``waters of the United States'' is consistent with the Supreme
                Court's approach in Maui. The Court also looked to scientific
                principles to inform its interpretation of the Clean Water Act's
                jurisdictional scope, noting: ``[m]uch water pollution does not come
                from a readily identifiable source. See 3 Van Nostrand's Scientific
                Encyclopedia, at 5801 (defining `Water Pollution'). Rainwater, for
                example, can carry pollutants (say, as might otherwise collect on a
                roadway); it can pollute groundwater, and pollution collected by
                unchanneled rainwater runoff is not ordinarily considered point source
                pollution.'' 140 S. Ct. at 1471. The Court further observed that
                ``[v]irtually all water, polluted or not, eventually makes its way to
                navigable water. This is just as true for groundwater. See generally 2
                Van Nostrand's Scientific Encyclopedia 2600 (10th ed. 2008) (defining
                `Hydrology').'' Id. at 1470. The Court then enumerated a series of
                factors relevant to determining whether a discharge is jurisdictional
                under the Act, many of which are scientifically based, including the
                nature of the material through which the pollutant travels and the
                extent to which the pollutant is diluted or chemically changed as it
                travels. Id. at 1476-77.
                 In carefully considering the objective of the Act and the best
                available science, the proposed rule's incorporation of the significant
                nexus standard is consistent with the legislative history of the Clean
                Water Act. The Supreme Court has noted that ``some Members of this
                Court have consulted legislative history when interpreting ambiguous
                statutory language.'' Bostock v. Clayton County, Georgia, 140 S. Ct.
                1731, 1749 (2020). In Bostock, the Court stated further that ``while
                legislative history can never defeat unambiguous statutory text,
                historical sources can be useful for a different purpose: Because the
                law's ordinary meaning at the time of enactment usually governs, we
                must be sensitive to the possibility a statutory term that means one
                thing today or in one context might have meant something else at the
                time of its adoption or might mean something different in another
                context. And we must be attuned to the possibility that a statutory
                phrase ordinarily bears a different meaning than the terms do when
                viewed individually or literally. To ferret out such shifts in
                linguistic usage or subtle distinctions between literal and ordinary
                meaning, this Court has sometimes consulted the understandings of the
                law's drafters.'' Id. at 1750.
                 Bills introduced in 1972 in both the House of Representatives and
                the Senate defined ``navigable waters'' as ``the navigable waters of
                the United States.'' See 2 Environmental Policy Div., Library of
                Congress, Legislative History of the Water Pollution Control Act
                Amendments of 1972 at 1069, 1698 (1973). The House and Senate
                Committees, however, expressed concern that the definition might be
                given an unduly narrow reading. Thus, the House Report observed: ``One
                term that the Committee was reluctant to define was the term `navigable
                waters.' The reluctance was based on the fear that any interpretation
                would be read narrowly. However, this is not the Committee's intent.
                The Committee fully intends that the term `navigable waters' be given
                the broadest possible constitutional interpretation unencumbered by
                agency determinations which have been made or may be made for
                administrative purposes.'' H.R. Rep. No. 92-911, at 131 (1972).
                 The Senate Report stated that ``[t]hrough a narrow interpretation
                of the definition of interstate waters the implementation [of the] 1965
                Act was severely limited. Water moves in hydrologic cycles and it is
                essential that discharge of pollutants be controlled at the source.''
                S. Rep. No. 92-414, at 77 (1971). The Conference Committee deleted the
                word ``navigable'' from the definition of ``navigable waters,'' broadly
                defining the term to include ``the waters of the United States.'' The
                Conference Report explained that the definition was intended to
                repudiate earlier limits on the reach of federal water pollution
                efforts: ``The conferees fully intend that the term `navigable waters'
                be given the broadest possible
                [[Page 69397]]
                constitutional interpretation unencumbered by agency determinations
                which have been made or may be made for administrative purposes.'' S.
                Conf. Rep. No. 92-1236, at 144 (1972).
                 The significant nexus standard is also consistent with prior
                Supreme Court decisions, and with every circuit decision that has
                gleaned a rule of law from that precedent. For example, in Riverside
                Bayview, the Court deferred to the agencies' interpretation: ``In view
                of the breadth of federal regulatory authority contemplated by the Act
                itself and the inherent difficulties of defining precise bounds to
                regulable waters, the Corps' ecological judgment about the relationship
                between waters and their adjacent wetlands provides an adequate basis
                for a legal judgment that adjacent wetlands may be defined as waters
                under the Act.'' 474 U.S. at 134. In Rapanos, Justice Kennedy stated of
                the Court in Riverside Bayview ``the Court indicated that `the term
                ``navigable'' as used in the Act is of limited import,' 474 U.S., at
                133, [and] it relied, in upholding jurisdiction, on the Corps' judgment
                that `wetlands adjacent to lakes, rivers, streams, and other bodies of
                water may function as integral parts of the aquatic environment even
                when the moisture creating the wetlands does not find its source in the
                adjacent bodies of water,' id., at 135.'' 547 U.S. at 779 (Kennedy, J.,
                concurring). ``The implication,'' Justice Kennedy observed, ``was that
                wetlands' status as `integral parts of the aquatic environment'--that
                is, their significant nexus with navigable waters--was what established
                the Corps' jurisdiction over them as waters of the United States.'' Id.
                (emphasis added); see also id. at 780 (``[W]etlands' ecological
                functions vis-[aacute]-vis other covered waters are the basis for the
                Corps' regulation of them.''). The Court in SWANCC also characterized
                its decision in Riverside Bayview as informed by the ``significant
                nexus between the wetlands and `navigable waters.' '' 531 U.S. at 167.
                 In Rapanos, Justice Kennedy reasoned that Riverside Bayview and
                SWANCC ``establish the framework for'' determining whether an assertion
                of regulatory jurisdiction constitutes a reasonable interpretation of
                ``navigable waters,'' finding that ``the connection between a
                nonnavigable water or wetland and a navigable water may be so close, or
                potentially so close, that the Corps may deem the water or wetland a
                `navigable water' under the Act,'' and ``[a]bsent a significant nexus,
                jurisdiction under the Act is lacking.'' 547 U.S. at 767. Justice
                Kennedy also identified many of the same valuable functions of wetlands
                identified in the Science Report:
                 Important public interests are served by the Clean Water Act in
                general and by the protection of wetlands in particular. To give
                just one example, amici here have noted that nutrient-rich runoff
                from the Mississippi River has created a hypoxic, or oxygen-
                depleted, ``dead zone'' in the Gulf of Mexico that at times
                approaches the size of Massachusetts and New Jersey. Brief for
                Association of State Wetland Managers et al. 21-23; Brief for
                Environmental Law Institute 23. Scientific evidence indicates that
                wetlands play a critical role in controlling and filtering runoff.
                See, e.g., OTA 43, 48-52; R. Tiner, In Search of Swampland: A
                Wetland Sourcebook and Field Guide 93-95 (2d ed. 2005); Whitmire &
                Hamilton, Rapid Removal of Nitrate and Sulfate in Freshwater Wetland
                Sediments, 34 J. Env. Quality 2062 (2005).
                Id. at 777-78.
                 The agencies are mindful of the Supreme Court's decision in SWANCC
                regarding the specific Commerce Clause authority Congress was
                exercising in enacting the Clean Water Act. The Court noted that the
                statement in the Conference Report for the Act that the conferees
                ``intend that the term `navigable waters' be given the broadest
                possible constitutional interpretation,'' S. Conf. Rep. No. 92-1236, at
                144 (1972), signifies Congress's intent with respect to its exertion of
                its commerce power over navigation and no more. In light of the
                ambiguous nature of the phrase ``waters of the United States,'' the
                agencies have found the legislative history concerning the intent of
                Congress regarding the scope of the Act's protections under its power
                over navigation confirms the reasonableness of the proposed rule. The
                rule would ensure that all waters that either alone or in combination
                significantly affect the integrity of traditional navigable waters,
                interstate waters, or the territorial seas are protected under the
                Clean Water Act. The Supreme Court has long held that authority over
                traditional navigable waters is not limited to either protection of
                navigation or authority over only the traditional navigable water.
                Rather, ``the authority of the United States is the regulation of
                commerce on its waters . . . [f]lood protection, watershed development,
                [and] recovery of the cost of improvements through utilization of power
                are likewise parts of commerce control.'' United States v. Appalachian
                Electric Power Co., 311 U.S. 377, 426 (1940); see also Oklahoma ex rel.
                Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 525-526 (1941) (``[J]ust
                as control over the non-navigable parts of a river may be essential or
                desirable in the interests of the navigable portions, so may the key to
                flood control on a navigable stream be found in whole or in part in
                flood control on its tributaries. . . . [T]he exercise of the granted
                power of Congress to regulate interstate commerce may be aided by
                appropriate and needful control of activities and agencies which,
                though intrastate, affect that commerce.''). Again, to quote the Sixth
                Circuit after the 1972 enactment of the Clean Water Act: ``It would, of
                course, make a mockery of [Congress's] powers if its authority to
                control pollution was limited to the bed of the navigable stream
                itself. The tributaries which join to form the river could then be used
                as open sewers as far as federal regulation was concerned. The
                navigable part of the river could become a mere conduit for upstream
                waste.'' United States v. Ashland Oil & Transp. Co., 504 F.2d 1317,
                1326 (6th Cir. 1974). The significant nexus standard included in the
                proposed rule remains well within the bounds of SWANCC.
                ii. The Relatively Permanent Standard Is Administratively Useful, but
                Insufficient To Meet the Objective of the Clean Water Act
                 The agencies also conclude that federal protection is appropriate
                where a water meets the relatively permanent standard. Waters that meet
                this standard are an example of a subset of waters that will virtually
                always have the requisite connection to downstream traditional
                navigable waters, interstate waters, or the territorial seas, and
                therefore properly fall within the Clean Water Act's scope. However,
                the relatively permanent standard is insufficient as the sole standard
                for geographic jurisdiction under the Clean Water Act as it is
                inconsistent with the Act's text and objective and runs counter to the
                science.
                 Science supports that tributaries of traditional navigable waters
                with relatively permanent, standing, or continuously flowing water and
                wetlands and relatively permanent open waters with continuous surface
                connections to such relatively permanent waters perform important
                functions that either individually or cumulatively with similarly
                situated waters in the region have substantial effects on the chemical,
                physical, or biological integrity of downstream foundational waters.
                See Technical Support Document section IV.A. For example, perennial and
                seasonally intermittent tributaries contribute consistent flow to
                downstream foundational waters, and with that flow export nutrients,
                sediment, and food resources, contaminants, and other
                [[Page 69398]]
                materials that can both positively (e.g., by contributing to downstream
                baseflow, providing food for aquatic species, contributing to
                downstream aquatic habitat) and negatively (e.g., if exporting too much
                sediment, runoff, or nutrients or if exporting pollutants) affect the
                integrity, including the water quality, of those larger downstream
                waters. In addition, wetlands with a continuous surface connection to
                such relatively permanent waters can attenuate floodwaters, trap
                sediment, and process and transform nutrients that might otherwise
                reach downstream traditional navigable waters, interstate waters, or
                the territorial seas. The relatively permanent standard is useful
                because it generally requires less information gathering and assessment
                and because it focuses on flow and includes wetlands with a continuous
                surface connection. As such, while both the significant nexus and
                relatively permanent standards require fact-specific inquiries before
                determining whether a water is a ``water of the United States,'' the
                relatively permanent standard will generally require less assessment.
                 Standing alone as the sole test for Clean Water Act jurisdiction,
                the relatively permanent standard is insufficient. The standard's
                apparent exclusion of major categories of waters from the protections
                of the Clean Water Act, specifically with respect to tributaries that
                are not relatively permanent (such as ephemeral streams) and adjacent
                wetlands that do not have a continuous surface water connection to
                other jurisdictional waters, is inconsistent with the Act's text and
                objective and runs counter to the science demonstrating how such waters
                can affect the integrity of downstream waters, including traditional
                navigable waters, interstate waters, and territorial seas. The NWPR,
                for example, excluded federal jurisdiction over the many ephemeral
                tributaries that regularly and directly provide sources of freshwater
                to the sparse traditional navigable waters in the arid Southwest, such
                as portions of the Gila River.
                 As discussed in section V.A.2.c of this preamble, there is
                overwhelming scientific information demonstrating the effects ephemeral
                streams can have on downstream waters and the effects wetlands can have
                on downstream waters when they do not have a continuous surface
                connection. The science is clear that aggregate effects of ephemeral
                streams ``can have substantial consequences on the integrity of the
                downstream waters'' and that the evidence of such downstream effects is
                ``strong and compelling.'' Science Report at 6-10, 6-13. EPA's Science
                Advisory Board (SAB) Review of the draft Science Report explained that
                ephemeral streams ``are no less important to the integrity of the
                downgradient waters'' than perennial or intermittent streams. Letter
                from SAB to Gina McCarthy, Administrator, EPA (Oct. 17, 2014) (``SAB
                Review'') at 22-23, 54 fig. 3. The agencies also find no exclusion of
                waters that are not relatively permanent in the text of the statute.
                Rapanos, 547 U.S. at 770 (``To be sure, Congress could draw a line to
                exclude irregular waterways, but nothing in the statute suggests it has
                done so.'') (Kennedy, J., concurring).
                 The science is also clear that wetlands may significantly affect
                downstream waters when they have other types of surface connections,
                such as wetlands that overflow and flood jurisdictional waters or
                wetlands with less frequent surface water connections due to long-term
                drought; wetlands with shallow subsurface connections to other
                protected waters; or other wetlands proximate to jurisdictional waters.
                Such wetlands provide a number of functions, including water storage
                that can help reduce downstream flooding, recharging groundwater that
                contributes to baseflow of downstream rivers, improving water quality
                through processes that remove, store, or transform pollutants such as
                nitrogen, phosphorus, and metals, and serving as unique and important
                habitats including for aquatic species that also utilize larger
                downstream waters. See, e.g., Science Report at 4-20 to 4-38. For
                example, adjacent, interdunal wetlands separated from the Atlantic
                Ocean only by beach dunes would not meet the relatively permanent
                standard, but provide numerous functions, including floodwater storage
                and attenuation, storage and transformation of sediments and
                pollutants, and important habitat for species that utilize both the
                wetlands and the ocean, that significantly affect the Atlantic Ocean
                (both a traditional navigable water and territorial sea).
                 In addition, the agencies see no basis in the text or the science
                to exclude waters from Clean Water Act jurisdiction based solely on the
                continuous surface connection requirement. As discussed in section
                V.A.2.a of this preamble, the objective of the Act is to restore and
                maintain the water quality of the nation's waters. Nowhere does the Act
                refer to a continuous surface connection, and the imposition of such a
                limitation would not account for the science regarding how upstream
                waters and wetlands affect downstream foundational waters. As discussed
                above in this section and in the Technical Support Document, the
                science supports that wetlands and open waters that lack a continuous
                surface connection to relatively permanent waters can individually and
                cumulatively have more than a speculative or insubstantial effect on
                the chemical, physical, and biological integrity of traditional
                navigable waters, interstate waters, or the territorial seas. As a
                scientific matter, the agencies agree with Justice Kennedy that the
                Clean Water Act intends to protect waters that do not meet the
                relatively permanent standard, where such waters have a significant
                nexus. Rapanos, 547 U.S. at 773-74 (``Needless to say, a continuous
                connection is not necessary for moisture in wetlands to result from
                flooding--the connection might well exist only during floods.'')
                (Kennedy, J., concurring); see also id at 775 (``In many cases,
                moreover, filling in wetlands separated from another water by a berm
                can mean that floodwater, impurities, or runoff that would have been
                stored or contained in the wetlands will instead flow out to major
                waterways. With these concerns in mind, the Corps' definition of
                adjacency is a reasonable one, for it may be the absence of an
                interchange of waters prior to the dredge and fill activity that makes
                protection of the wetlands critical to the statutory scheme.'').
                 While the relatively permanent standard is administratively useful
                and includes waters that have important effects on downstream water
                quality, the standard excludes many waters that properly fall within
                the Act's protections. As a result, the proposed rule's incorporation
                of both Rapanos standards represents a reasonable interpretation of
                broad and ambiguous statutory text and a permissible way for the
                agencies to fulfill their congressionally delegated responsibility to
                interpret ``waters of the United States'' in a manner that advances the
                objective of the Act.
                iii. Fact-Based Standards for Determining Clean Water Act Jurisdiction
                Are Reasonable
                 Finally, while a fact-dependent jurisdictional analysis of whether
                a water meets either the relatively permanent standard or the
                significant nexus standard does not necessarily provide categorical
                certainty, case-specific determinations of the scope of Clean Water Act
                jurisdiction are not unique. In the Supreme Court's most recent
                decision addressing a question about the jurisdictional scope of the
                Clean Water Act, although not the scope of ``waters of the United
                States,'' the Court established a standard for
                [[Page 69399]]
                determining jurisdiction that, like the significant nexus standard,
                does not establish bright lines marking the bounds of federal
                jurisdiction and instead requires an inquiry focused on the specific
                facts at issue and guided by the purposes Congress sought to achieve
                under the Act. In Maui, the Supreme Court considered whether discharges
                to groundwater that reach navigable waters are jurisdictional under the
                Act and thus subject to the Act's section 402 permitting program. The
                Court held that ``the statute requires a permit when there is a direct
                discharge from a point source into navigable waters or when there is
                the functional equivalent of a direct discharge.'' Maui, 140 S. Ct. at
                1476. The Court explained that ``[w]e think this phrase best captures,
                in broad terms, those circumstances in which Congress intended to
                require a federal permit.'' Id. The Court further explained that, in
                applying its broadly worded standard, ``[t]he object in a given
                scenario will be to advance, in a manner consistent with the statute's
                language, the statutory purposes that Congress sought to achieve.'' Id.
                The Court recognized that the difficulty with its approach was that
                ``it does not, on its own, clearly explain how to deal with middle
                instances,'' but reasoned that ``there are too many potentially
                relevant factors applicable to factually different cases for this Court
                now to use more specific language.'' Id. The Court enumerated a series
                of factors relevant to determining whether a discharge is the
                ``functional equivalent'' of direct discharge, including the time
                between when the discharge occurs and when the pollutants reach the
                navigable water, the distance the pollutants travel to the navigable
                water, the nature of the material through which the pollutant travels,
                the extent to which the pollutant is diluted or chemically changed as
                it travels, the amount of pollutant entering the navigable waters
                relative to the amount of the pollutant that leaves the point source,
                the manner by or area in which the pollutant enters the navigable
                waters, and the degree to which the pollution (at that point) has
                maintained its specific identity. Id. at 1476-77.
                 The Supreme Court's ``functional equivalent'' standard has several
                key characteristics in common with the significant nexus standard and
                the agencies' approach in the proposed rule. Both standards require an
                analysis focused on the specific facts at issue in a particular
                instance. The ``functional equivalent'' standard requires consideration
                of facts related to the discharge at issue, the geologic substrate
                through which the discharges travels, the location and nature of the
                receiving water, and other factors. Likewise, the significant nexus
                standard requires consideration of scientific principles of upstream
                functions and effects on the integrity of downstream waters and facts
                related to the specific waters at issue. Indeed, the agencies have
                proposed a list of factors that would be considered when assessing
                whether waters ``significantly affect'' foundational waters that is
                similar in nature to the factors identified by the Court for making a
                ``functional equivalent'' assessment. See section V.C.10 of this
                preamble. The relatively permanent standard also requires inquiry into
                specific facts about particular tributaries and wetlands, although the
                inquiry generally requires less information gathering and assessment
                than the significant nexus standard. The Court in Maui also explicitly
                rejected EPA's suggested approach which established a bright line that
                categorically excluded all discharges to groundwater regardless of
                whether they reached navigable waters and instead adopted the
                ``functional equivalent'' analysis. 140 S. Ct. at 1474-75. Likewise,
                the significant nexus standard also does not necessarily establish
                bright lines with respect to determining which waters have a sufficient
                impact on downstream traditional navigable waters, interstate waters,
                or the territorial seas, in contrast to the NWPR which categorically
                excluded all ephemeral waters in spite of their impact on the chemical,
                physical, and biological integrity of downstream foundational waters.
                 Finally, both the functional equivalent standard and the
                significant nexus standard should be applied while keeping in mind the
                purposes of the Act. As the Court explained in Maui, ``[t]he underlying
                statutory objectives also provide guidance. Decisions should not create
                serious risks either of undermining state regulation of groundwater or
                of creating loopholes that undermine the statute's basic federal
                regulatory objectives.'' Id. at 1477. Likewise, Justice Kennedy
                explained that when assessing the existence of a ``significant nexus''
                between wetlands and navigable waters, ``[t]he required nexus must be
                assessed in terms of the statute's goals and purposes.'' Rapanos, 547
                U.S. at 779.
                 The agencies recognize that in both Rapanos and Maui the Supreme
                Court was clear that the agencies could promulgate regulations that
                further refine the case-specific jurisdictional tests. The agencies'
                goal with this proposed rule is to return to the familiar and
                longstanding framework that will ensure Clean Water Act regulatory
                protections, informed by relevant Supreme Court decisions. The agencies
                also anticipate developing another rule that builds upon the regulatory
                foundation of this rule with the benefit of additional stakeholder
                engagement and which could, among many issues, consider more
                categorical approaches to jurisdiction.
                b. The Proposed Rule Reflects Full and Appropriate Consideration of the
                Water Quality Objective in Section 101(a) and the Policies Relating to
                Responsibilities and Rights of States and Tribes Under Section 101(b)
                of the Act
                 The proposed rule reflects consideration of the statute as a whole,
                including the objective of the Act and the policies of the Act with
                respect to the role of states and tribes. As discussed in section
                V.A.2.a of this preamble, the agencies must consider the objective of
                the Clean Water Act in interpreting the scope of the statutory term
                ``waters of the United States.'' In this proposed rule, the agencies
                also consider the entire statute, including section 101(b) of the Clean
                Water Act, which provides that it is Congressional policy to preserve
                the primary responsibilities and rights of states ``to prevent, reduce,
                and eliminate pollution, to plan the development and use . . . of land
                and water resources, and to consult with the Administrator with respect
                to the exercise of the Administrator's authority'' under the Clean
                Water Act. 33 U.S.C. 1251(b). Determining where to draw the boundaries
                of federal jurisdiction to both ensure that the agencies achieve
                Congress's objective while preserving and protecting the
                responsibilities and rights of the states is a matter of judgment
                assigned by Congress to the agencies.
                 The agencies find that the proposed rule both advances the
                objective of the Act in section 101(a) and respects the role of states
                and tribes in 101(b).\28\ The proposed rule appropriately draws the
                boundary of waters subject to federal protection by extending, and
                limiting, it to the protection of upstream waters that significantly
                affect the integrity of waters where the federal interest is
                indisputable--the traditional navigable waters, interstate waters, and
                territorial seas. Waters that do not implicate federal interest in
                these foundational
                [[Page 69400]]
                waters are left entirely to state and tribal protection and management.
                ---------------------------------------------------------------------------
                 \28\ While Clean Water Act section 101(b) does not specifically
                identify tribes, the policy of preserving states' sovereign
                authority over land and water use is equally relevant to ensuring
                the primary authority of tribes to address pollution and plan the
                development and use of tribal land and water resources.
                ---------------------------------------------------------------------------
                 The scope and boundaries of the proposed definition therefore
                reflect the agencies' considered judgment of both the Act's objective
                in section 101(a) and the Congressional policy relating to states'
                rights and responsibilities under section 101(b). In several key
                respects, the agencies' consideration and weighing of these provisions
                in this rulemaking differs from the agencies' approach in the NWPR.
                Those differences and the bases for them follow.
                i. Consideration of Sections 101(a) and 101(b) in the NWPR
                 In promulgating the NWPR, the agencies gave predominant weight to
                consideration of the policy in section 101(b), citing it frequently in
                its rationale for the rule generally. For example, the agencies stated:
                ``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.'' 85 FR
                22269, April 21, 2020. The agencies also opined on the relationship
                between its consideration of section 101(a) and 101(b): ``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). The oft-quoted objective of the CWA to `restore and maintain
                the chemical, physical, and biological integrity of the Nation's
                waters,' . . . must be implemented in a manner consistent with
                Congress' policy directives to the agencies.'' Id. The NWPR ultimately
                concluded that the rule ``appropriately balances . . . the objective of
                the Act and the policy of Congress set forth in CWA sections 101(a) and
                101(b), respectively.'' Id. at 22277.
                 Beyond relying on section 101(b) for the agencies' overall approach
                to the rulemaking, the NWPR relied specifically on section 101(b) as a
                basis for the rule's line-drawing between jurisdictional and non-
                jurisdictional waters. For example, with regard to tributaries, the
                agencies stated that limiting jurisdiction to waters that contribute
                surface flow to traditional navigable waters in a typical year ``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).'' Id. at 22287. The agencies contended,
                moreover, that excluding ephemeral waters from jurisdiction
                ``respect[s] State and Tribal land use authority over features that are
                only episodically wet during and/or following precipitation events.''
                Id. at 22319. With regard to wetlands, the agencies similarly relied
                upon ``limitations on federal authority embodied in CWA section
                101(b)'' as a justification for excluding subsurface hydrologic
                connectivity as a basis for determining what constitutes an adjacent
                wetland. Id. at 22313.
                ii. Consideration of Sections 101(a) and 101(b) in Developing the
                Proposed Rule
                 The agencies have carefully considered sections 101(a) and 101(b)
                as well as the agencies' analysis and application of these provisions
                in promulgating the NWPR. As discussed below, based on the text of
                section 101(b), the structure of section 101 and the Act as a whole,
                Supreme Court precedent, and the history of federal water pollution
                laws enacted by Congress up through the 1972 Amendments, the agencies
                believe that the proposed rule reflects fuller and more appropriate
                consideration of sections 101(a) and 101(b) than the agencies undertook
                in promulgating the NWPR.
                 As a threshold matter, the agencies agree that the policy in
                section 101(b) is both important and relevant to the agencies' defining
                an appropriate scope of ``waters of the United States.'' Consistent
                with the text of the statute and as emphasized by the Supreme Court,
                federal jurisdiction under the Clean Water Act has limits. As explained
                above, Clean Water Act jurisdiction encompasses (and is limited to)
                those waters that significantly affect the indisputable federal
                interest in the protection of the foundational waters that prompted
                Congress to enact the various incarnations of the Act--i.e.,
                traditional navigable waters, interstate waters, and the territorial
                seas. And consistent with the section 101(b) policy, where protection
                (or degradation) of waters do not implicate this federal interest, such
                waters fall exclusively within state or tribal regulatory authority,
                should they choose to exercise it.
                 The agencies' considered view at this time differs, however, in
                certain important respects from how the NWPR considered section 101(b).
                As the above statements make clear, section 101(b) was not simply a
                relevant consideration for the NWPR, but a key lynchpin of both the
                overall regulatory approach and the rule's specific definitions of
                jurisdictional waters. In the agencies' view, the better reading of
                section 101(b) does not support the heavy weight accorded to it by the
                NWPR for either its overall approach nor its specific definitions.
                (1) The Text of Section 101(b)
                 First, the agencies believe that the NWPR's reading of section
                101(b) fails to align with the better reading of the text of section
                101(b). For example, the agencies stated in support of the NWPR that
                ``[i]n 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).'' 85 FR 22269, April 21, 2020
                (emphasis added). However, this appears to be a restatement of the
                first sentence of section 101(b), which actually states:
                 It is the policy of the Congress to recognize, preserve, and
                protect the primary responsibilities and rights of States to
                prevent, reduce, and eliminate pollution, to plan the development
                and use (including restoration, preservation, and enhancement) of
                land and water resources, and to consult with the Administrator in
                the exercise of his authority under this Act.
                 The NWPR read this provision as essentially agnostic (or even in
                opposition) to preventing pollution and meeting the objective of Act.
                See, e.g., 85 FR 22270, April 21, 2020 (``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 believe the better
                reading of this provision is found in the text of section 101(b), as a
                recognition of states' authority to ``prevent, reduce, and eliminate
                pollution'' and provide support for the Administrator's exercise of his
                authority to advance the objective of the Act. Indeed, section 101(b)'s
                text is plainly focused on environmental protection (``prevent, reduce,
                and eliminate pollution,'' ``including restoration, preservation and
                enhancement[] of land and water resources'').
                 Section 101(b) further recognizes the very important role that the
                states play in achieving the Act's objective. ``Pollution'' is a
                defined term in the Act that means ``man-made or man-induced alteration
                of the chemical, physical, biological, and radiological integrity of
                water'' (section 502(19)) and has a broader scope than the ``discharge
                of a pollutant'' subject to regulatory jurisdiction under the Clean
                Water Act (e.g., nonpoint sources of pollution). The agencies believe
                that Congress's use of the broad term ``pollution'' in section
                [[Page 69401]]
                101(b) indicates that the policy in this section is intended to
                recognize and preserve, among other things, states' authority to
                prevent, reduce, and eliminate all kinds of pollution, including
                pollution falling outside the scope of federal regulatory authority.
                Importantly, this includes all non-point sources, which indisputably
                may (and do) significantly affect the integrity of foundational waters.
                The agencies' proposed definition of ``waters of the United States''
                does not implicate, let alone impinge, on such state authorities.
                 The first sentence of section 101(b) also refers to states'
                ``primary'' role in preventing, reducing, and eliminating pollution--a
                word that is not incompatible with overlapping federal and state
                authority over waters which, under the proposed rule, implicate core
                federal interests. Thus, the text of section 101(b) need not be read,
                and in the agencies' view is best not read, as a general policy in
                favor of preserving for states a zone of exclusive regulatory authority
                based on federalism principles ``to choose whether or not to regulate''
                regardless of the impact of those decisions on achievement of the Act's
                objective. See 85 FR 22270, April 21, 2020.
                 In developing the proposed rule, the agencies also considered the
                language in section 101(b) referring to states' rights and
                responsibilities ``to plan the development and use (including
                restoration, preservation, and enhancement) of land and water
                resources.'' Planning the development, use, and protection of land and
                water resources is indisputably a traditional state function (e.g.,
                zoning, allocation and administration of water rights, exercise of
                eminent domain, preservation of lands and waters). Congress's
                recognition of the states' primary role in this domain does not state
                or even suggest a policy to limit Clean Water Act jurisdiction over
                waters, as would be covered under the proposed rule, implicating the
                core federal interest in protecting traditional navigable waters,
                interstate waters and the territorial seas.
                 Indeed, any implication to the contrary is dispelled by the
                remainder of section 101(b), which, among other things, expressly
                recognizes states' role in administering the federal permitting
                programs under section 402 of the Act:
                 It is the policy of Congress that the States manage the
                construction grant program under this Act and implement the permit
                programs under sections 402 and 404 of this Act. It is further the
                policy of the Congress to support and aid research relating to the
                prevention, reduction, and elimination of pollution, and to provide
                Federal technical services and financial aid to State and interstate
                agencies and municipalities in connection with the prevention,
                reduction, and elimination of pollution.
                 Thus, in the agencies' view, the text of section 101(b) as a whole
                reflects not a general policy of deference to state regulation to the
                exclusion of Federal regulation, but instead a policy focused on
                preserving the responsibilities and rights of states to work to achieve
                the objective of the Act by preventing, reducing and eliminating
                pollution generally, including, but not limited to, through their
                authority over any source of pollution subject to state law, consulting
                with the Administrator in the exercise of his Clean Water Act
                authority, and implementing the Act's regulatory permitting programs,
                in partnership and with technical and financial support from the
                Federal government.
                 In the preamble to the NWPR, the agencies criticized prior
                statements they had made as taking an unduly narrow view of 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.''' 85 FR 22269, April 21, 2020. As indicated above, the
                agencies now view the policy in section 101(b) as encompassing a broad
                understanding of states' roles in preventing, reducing, and eliminating
                pollution, and as explained above, the proposed rule reflects due
                consideration of this provision.
                 The agencies' interpretation and consideration of section 101(b) in
                this rulemaking is consistent with Supreme Court precedent. The Supreme
                Court has described, on numerous occasions, section 101(b) as creating
                a partnership between the federal and state governments, in which the
                states administer programs under federally mandated standards and are
                allowed to set even more stringent standards. See Arkansas v. Oklahoma,
                503 U.S. at 144 (describing ``partnership between the States and the
                Federal government'' to meet 101(a) objective of Federal government
                setting pollutant discharge limitations and States implementing water
                quality standards for water bodies themselves); Int'l Paper Co. v.
                Ouellette, 479 U.S. at 489-90 (explaining 101(b) as allowing Federal
                government to delegate administration of point source pollution permits
                to states and allowing states to establish more stringent discharge
                limitations than federal requirements); City of Milwaukee, 451 U.S. at
                341 (describing 101(b) as creating ``shared authority between the
                Federal Government and the Individual States'' that allows for the
                states to set more stringent standards than necessary by federal law);
                Colorado Public Interest Group, 426 U.S. at 16, n.13 (describing 101(b)
                as providing states authority to develop permit programs and
                establishing standards more stringent than the Clean Water Act).
                (2) Relationship Between Sections 101(a) and 101(b)
                 The agencies have also carefully considered the policy in section
                101(b) as it relates to the Act's objective in section 101(a) and have
                reconsidered how the agencies considered these two provisions in
                promulgating the NWPR.
                 In the preamble to the final NWPR, the agencies stated: ``The oft-
                quoted objective of the CWA to `restore and maintain the chemical,
                physical, and biological integrity of the Nation's waters,' . . . must
                be implemented in a manner consistent with Congress' policy directives
                to the agencies.'' 85 FR 22269, April 21, 2020. As discussed above, the
                agencies gave section 101(b) predominant weight, and relied upon it as
                the basis for the rule's line-drawing between jurisdictional and non-
                jurisdictional waters. Upon further review and reconsideration, while
                the agencies agree with the view in the NWPR that section 101(b) is
                relevant to a rulemaking defining ``waters of the United States'' (and
                have given the provision due consideration, as discussed above), the
                agencies are giving greater weight to section 101(a) than did the NWPR,
                and conclude that section 101(b) is better read as supporting
                Congress's objective in the Clean Water Act than in tension with it.
                 The Clean Water Act's structure makes clear that section 101(a) is
                the foundational purpose of the statute that must be achieved. First,
                section 101(a) is the opening section of the statute and is labelled
                the ``objective'' of the Act. The agencies interpret its placement and
                its simple, declarative, and overarching statement as a powerful
                expression by Congress that merits significant weight in defining the
                scope of jurisdiction for all of the Clean Water Act's regulatory
                programs. In contrast, section 101(b) is one of four Congressional
                policies contained in section 101; the other three relate to seeking to
                ensure foreign countries take action to prevent, reduce, and eliminate
                pollution; reducing paperwork, duplication, and government delays; and
                state authority to allocate quantities of water within their
                jurisdictions. See 33 U.S.C. 1251(c), (f) and (g). The agencies believe
                that the prominently placed and single expression of the Act's
                overarching objective in section 101(a) merits greater weight in the
                agencies' decision-making than one of the four Congressional
                [[Page 69402]]
                policies expressed in section 101 which, while important, appear
                subordinate to the objective--particularly given the statutory text and
                structure.
                 The remainder of the Act's text also demonstrates how important
                this objective was to Congress. As the NWPR accurately stated, the
                objective in section 101(a) is ``oft-quoted'' 85 FR 22269, April 21,
                2020. In the Clean Water Act itself, Congress refers to the objective
                of the Act approximately a dozen times, including in sections 122, 217,
                301, 302, 304, 305, 308, 318, 402, 405, 505, 516, 518, 601, and 603.
                The repeated reference to section 101(a) highlights the importance of
                the Act's objective to the statute as a whole, supporting the agencies'
                giving significant weight to this provision. Section 101(b), in
                contrast, is not referred to elsewhere in the Act.
                 Indeed, while the NWPR read section 101(b) in isolation from the
                rest of the Clean Water Act, reviewing the statute as a whole reveals
                that Congress itself gave direction to the agencies on how it expected
                them to achieve section 101(a)'s objective and implement section
                101(b)'s policy. Following section 101, the remainder of the Act
                provides extensive and detailed instruction on how Congress expected
                its objective, goals, and policies to be met through the Act.
                Specifically, with regard to its objective and goals in section 101(a),
                Congress laid out a series of detailed programs (e.g., the section 303
                water quality standards program, the section 402 discharge elimination
                program, and the section 404 dredge and fill program) designed to meet
                that objective. So too, Congress gave detailed instructions on how it
                intended to apply its policy of preserving the primary role of the
                states. Specifically, as referenced explicitly in section 101(b), it
                authorized states to implement the key permitting programs under
                sections 402 and 404 of the Act--i.e., their authority to assume
                administration of the federal regulatory program for discharges of
                pollutants under sections 402(b) and 404(g). The Clean Water Act
                likewise delineates a role for states in implementing numerous other
                Clean Water Act programs central to achieving the Act's objective,
                including the water quality standards program and impaired waters and
                total maximum daily load program in section 303. Section 401 grants
                primary authority to states and authorized tribes to grant, deny, or
                waive certification of proposed federal licenses or permits that may
                discharge into ``waters of the United States'' within their borders.
                And under section 510, unless expressly stated, nothing in the Clean
                Water Act precludes or denies the right of any state or tribe to
                establish more protective standards or limits than the Act. As
                described above, the Clean Water Act further assigns exclusive
                authority to the states to regulate non-point sources.
                 Thus, the agencies choose not to read the policy of section 101(b)
                as essentially a free-floating instruction or license for the agencies
                to interpret or implement other sections of the Act in a manner that
                impedes achievement of its overall objective, in particular
                definitional provisions like ``waters of the United States'' which are
                central to administration of the entire statute and therefore achieving
                that objective. To the contrary, Congress itself defined the contours
                of how it expected the agencies to both achieve its object in section
                101(a) and implement its policy in section 101(b) through the rest of
                the provisions of the Act. Notably, a narrow definition of ``waters of
                the United States'' would not uniformly boost state authority, as the
                NWPR suggested, as that definition is foundational to the scope of all
                of these programs in which the states are assigned authority. Indeed,
                with regard to section 401, a narrow definition would actually limit
                states' ability to protect waters within their borders.
                 Finally, section 101(a) has also been ``oft-quoted'' by the courts,
                including the U.S. Supreme Court. See, e.g., National Association of
                Manufacturers, 138 S. Ct. at 624 (``Congress enacted the Clean Water
                Act in 1972 `to restore and maintain the chemical, physical, and
                biological integrity of the Nation's waters.' 33 U.S.C. 1251(a).'');
                see supra section V.A.2 of this preamble (summarizing Supreme Court
                case law surrounding the Act's statutory objective).
                 The agencies' careful balancing of 101(a) and 101(b) in the
                proposed rule is also informed by and consistent with the Court in
                SWANCC, which noted that ``Congress chose to `recognize, preserve, and
                protect the primary responsibilities and rights of States . . . to plan
                the development and use . . . of land and water resources. . . .' 33
                U.S.C. [section] 1251(b). We thus read the statute as written to avoid
                the significant constitutional and federalism questions.'' U.S. 531 at
                174. Justice Kennedy further explained in Rapanos: ``In SWANCC, by
                interpreting the Act to require a significant nexus with navigable
                waters, the Court avoided applications--those involving waters without
                a significant nexus--that appeared likely, as a category, to raise
                constitutional difficulties and federalism concerns.'' 547 U.S. at 776.
                Likewise here, the proposed rule--by limiting jurisdiction only to
                those waters that significantly affect the integrity of waters where
                the federal interest is indisputable (traditional navigable waters,
                interstate waters, and the territorial seas)--would avoid
                constitutional and federalism concerns.
                 In sum, taking into account the prominence, text, repeated
                statutory references to section 101(a), the Supreme Court's
                highlighting of the central importance of this provision, and the fact
                that the vast majority of the rest of the Clean Water Act is primarily
                aimed towards meeting this objective, the agencies accord this section
                significant weight, and greater weight than the due consideration it
                has given section 101(b) in developing the proposed rule.
                (3) Statutory History
                 Finally, in considering sections 101(a) and 101(b) for purposes of
                interpreting the scope of ``waters of the United States,'' the agencies
                believe it is important to consider the statutory history that gave
                rise to this structure. Indeed, the agencies recognize that in passing
                the Federal Water Pollution Control Act Amendments of 1972, Congress
                was not acting on a blank slate--it was amending existing law that had
                primarily provided for states to establish water quality standards for
                a subset of waters. Water Quality Act of 1965, Public Law 89-234, 79
                Stat. 903 (1965). Congress found the previous statute's focus on
                states' establishment and administration of water quality standards
                insufficient for the task of upgrading and protecting the quality of
                America's waters because states were lagging in establishing such
                standards and there was ``an almost total lack of enforcement.'' S.
                Rep. 92-414, S. Rep. 92-414 (1971) at 3671, 72. The Clean Water Act was
                enacted to address these shortcomings after ``two of the important
                rivers [in the Sixth] circuit, the Rouge River in Dearborn, Michigan,
                and the Cuyahoga River in Cleveland, Ohio, reached a point of pollution
                by flammable materials in the last ten years that they repeatedly
                caught fire.'' United States. v. Ashland Oil & Transp. Co., 504 F.2d
                1317, 1326 (6th Cir. 1974).
                 With the 1972 Amendments, Congress adopted an entirely new approach
                to water pollution control--a prohibition of discharges of pollutants
                unless authorized by the Act and a new, comprehensive, federal
                regulatory scheme grounded in technology-based effluent standards
                applied uniformly across industries of the same type. ``The Committee
                recommends the change to effluent limits as the best available
                mechanism to control water pollution.
                [[Page 69403]]
                With effluent limits, the Administrator can require the best control
                technology.'' S. Rep. 92-414 at 3675. Congress further indicated that
                the Clean Water Act was intended to ``restore Federal-State balance to
                the permit system. Talents and capacities of those States whose own
                programs are superior are to be called upon to administer the permit
                system within their boundaries. The Administrator is to suspend his
                activity, insofar as the permit system is concerned, in these States.''
                Id. . Congress also viewed the prohibition on discharges of pollutants
                unless authorized under the Act as ``establish[ing] a direct link
                between the Federal government and each industrial source of discharge
                into the navigable waters.'' Id. Thus, Congress viewed the Clean Water
                Act as a change from previous laws that centered on states and state
                water quality standards to a system based on a prohibition of
                discharges of pollutants to waters unless permitted in accordance with
                a federal regulatory scheme and technology standards established by
                EPA. States and tribes play a vital role in the implementation and
                enforcement of the Clean Water Act and the proposed rule proposes
                limitations after carefully considering how best to identify those
                waters for which protections were better left to the states.
                 Thus, in passing the 1972 Amendments, Congress itself acted to
                rebalance its approach to protecting water quality--shifting from a
                statutory scheme dependent on state action to one rooted in a federal
                foundation, providing a uniform floor of water quality protection and
                leaving space for states to choose whether to regulate more
                stringently. See Dubois v. U.S. Dep't of Agriculture, 102 F.3d 1273,
                1300 (1st Cir. 1996) (``Simply put, the CWA provides a federal floor,
                not a ceiling, on environmental protection.''). Yet, in interpreting
                section 101(b) as serving to limit the scope of the Federal
                government's authority in favor of state authority, the NWPR turned
                Congress's scheme in the 1972 Amendments--in which it purposefully
                sought to give the Federal government a greater role in water quality
                protection--on its head. Unlike the NWPR, which did not consider the
                Act's statutory history in its read of section 101(b), the agencies
                here interpret section 101(b) in the context of this history and
                Congress's deliberate choice to restructure the statute to move away
                from its previous reliance on state-led water pollution control.
                 The Supreme Court has also long recognized that Congress, in
                enacting the Clean Water Act, ``intended the 1972 Act amendments to
                `establish an all-encompassing program of water pollution
                regulation.''' Int'l Paper Co. v. Ouellette, 479 U.S. 481, 492-93
                (1987); see, e.g., PUD No. 1 of Jefferson Cty v. Washington Dep't of
                Ecology, 511 U.S. 700, 704 (1994) (interpreting the scope of Clean
                Water Act section 401 and finding that the Act ``is a comprehensive
                water quality statute designed to `restore and maintain the chemical,
                physical, and biological integrity of the Nation's waters,''' that
                ``[t]he Act also seeks to attain `water quality which provides for the
                protection and propagation of fish, shellfish, and wildlife,''' and
                that ``to achieve these ambitious goals, the Clean Water Act
                establishes distinct roles for the Federal and State Governments'');
                EPA v. California ex rel. State Water Resources Control Bd., 426 U.S.
                200, 203, 205 n.12 (1976) (``In 1972, prompted by the conclusion of the
                Senate Committee on Public Works that `the Federal water pollution
                control program . . . has been inadequate in every vital aspect,'
                Congress enacted the [Clean Water Act] declaring `the national goal
                that the discharge of pollutants into the navigable waters be
                Eliminated by 1985.''). In the context of the scope of ``waters of the
                United States,'' the Court stated that Congress ``intended to repudiate
                limits that had been placed on federal regulation by earlier water
                pollution control statutes and to exercise its powers under the
                Commerce Clause to regulate at least some waters that would not be
                deemed `navigable' under the classical understanding of that term.''
                Riverside Bayview, 474 U.S. 121, 133. More recently, the Supreme Court
                in Maui noted that:
                 Congress' purpose as reflected in the language of the Clean
                Water Act is to ```restore and maintain the integrity of the
                Nation's waters,' '' [section] 101(a), 86 Stat. 816. Prior to the
                Act, Federal and State Governments regulated water pollution in
                large part by setting water quality standards. See EPA v. California
                ex rel. State Water Resources Control Bd., 426 U.S. 200, 202-203, 96
                S.Ct. 2022, 48 L.Ed.2d 578 (1976). The Act restructures federal
                regulation by insisting that a person wishing to discharge any
                pollution into navigable waters first obtain EPA's permission to do
                so. See id., at 203-205, 96 S.Ct. 2022; Milwaukee v. Illinois, 451
                U.S. 304, 310-311, 101 S.Ct. 1784, 68 L.Ed.2d 114 (1981).
                140 S. Ct. at 1468.
                 With respect to states' responsibilities and rights under section
                101(b), Justice Kennedy in Rapanos cited state amici briefs which
                ``note[d], among other things, that the Act protects downstream States
                from out-of-state pollution that they cannot themselves regulate.'' 547
                U.S. at 777. Indeed, the Supreme Court has recognized that this is an
                important aspect of the Clean Water Act's passage. City of Milwaukee
                involved alleged discharges of inadequately treated sewage from
                Milwaukee, Wisconsin sewer systems directly into Lake Michigan, which
                also borders Illinois. The Supreme Court noted that prior to passage of
                the Clean Water Act, these discharges would have had to be resolved
                through litigation, in which the courts must apply ``often vague and
                indeterminate nuisance concepts and maxims of equity jurisprudence.''
                451 U.S. at 317. The Clean Water Act, however, replaced this
                unpredictable and inefficient approach with ``a comprehensive
                regulatory program supervised by an expert administrative agency.'' Id.
                 Yet, an overly narrow definition of jurisdictional waters--such as
                that under the NWPR (including the NWPR's removal from jurisdiction the
                longstanding category of interstate waters) --threatens a return to
                pre-1972 days excluding from federal protection waters that
                significantly affect foundational waters and risks removing from the
                statutory scheme instances of interstate pollution the 1972 amendments
                were designed to address. In response to concerns expressed by
                commenters regarding protection of downstream states from out-of-state
                pollution, the agencies in the NWPR simply stated: ``The CWA provides a
                number of opportunities for the EPA to mediate disputes among states,
                though the remedies available for cross-boundary water pollution
                disputes over non-jurisdictional waters depends upon the parties and
                the issues of the case. As they do today, under the final rule remedies
                for pollution disputes among states that do not implicate CWA sections
                319(g), 401, or 402 would likely derive from federal common law under
                the Supreme Court's original jurisdiction. Remedies for disputes
                between a state and a public or private party would likely derive from
                state or federal common law and be heard by state or federal courts.''
                NWPR, Response to Comments, Topic 1 Legal Arguments at 26. But
                directing states and other parties to utilize state or federal common
                law to resolve such disputes overlooks ``Congress' intent in enacting
                the [1972] Amendments . . . to establish an all-encompassing program of
                water pollution regulation,'' City of Milwaukee, 451 U.S. at 318, and
                that ``the need for such an unusual exercise of lawmaking by federal
                courts disappears'' when Congress passes legislation that ``speak[s]
                directly'' to the question at issue, as Congress did in
                [[Page 69404]]
                passing the Clean Water Act. Id. at 317-18.
                 By proposing regulations interpreting the Act to cover waters that
                meet the relatively permanent standard or the significant nexus
                standard, the agencies have reasonably interpreted the Act to protect
                those waters necessary to protect the integrity of downstream
                traditional navigable waters, interstate waters, and the territorial
                seas while leaving regulatory authority over all other waters
                exclusively to the states. This interpretation respects the statutory
                history that gave rise to the Act and gives effect to the comprehensive
                nature of the Clean Water Act, its objective, and the many programs
                affected by the scope of ``waters of the United States'' designed to
                meet that objective, along with other important policies of the Act,
                while ensuring that states have sole authority over waters with no or
                insignificant connection to the foundational waters clearly protected
                by the Clean Water Act.
                (4) The Definitions of Jurisdictional Waters in the Proposed Rule
                Reflect Appropriate Consideration of Sections 101(a) and 101(b) of the
                Act
                 As discussed elsewhere, the proposed rule includes definitions of
                tributaries, adjacent wetlands, and ``other waters'' that meet the
                relatively permanent or significant nexus standards (see section V.C of
                this preamble). The proposed rule advances the Act's objective by
                helping restore and maintain the chemical, physical, and biological
                integrity of traditional navigable waters, interstate waters, and
                territorial seas--waters of longstanding and indisputable federal
                interest--by protecting them from degradation of upstream waters that
                significantly affect them. At the same time, consistent with section
                101(b), the proposed rule recognizes, preserves, and protects states'
                rights and responsibilities subject to the policy in section 101(b) of
                the Act by leaving within their purview all waters that do not
                significantly affect the foundational waters of paramount federal
                interest. The specific jurisdictional lines in the proposed rule
                demarcating jurisdictional from non-jurisdictional waters therefore
                bear a relationship to the nature and extent of federal and state
                interests at play; this line-drawing highlights the agencies'
                deliberate and due consideration of sections 101(a) and 101(b) in
                developing the proposed rule.
                 The agencies believe that the jurisdictional line-drawing reflected
                in the proposed rule better aligns with these statutory provisions than
                the NWPR. As noted previously, the preamble to the final NWPR cited
                section 101(b) as a justification, in part, for its specific
                definitions of jurisdictional tributaries and adjacent wetlands. One of
                the most environmentally significant decisions in the NWPR was its
                categorical exclusion of all ephemeral streams from Clean Water Act
                jurisdiction. The agencies cited section 101(b) as a basis for this
                exclusion as ``respecting State and Tribal land use authority over
                features that are only episodically wet during and/or following
                precipitation events.'' 85 FR 22319. The agencies' explanation,
                however, does not link the agencies' line-drawing to the text or
                purpose of section 101(b). Nor do the agencies, at this time, see any
                linkage between the flow regime of ephemeral waters and the nature or
                extent of state authorities referenced in section 101(b). Indeed, as
                discussed elsewhere, available science unequivocally demonstrates that
                ephemeral tributaries can implicate the important federal interest in
                the protection of the integrity of traditional navigable waters,
                interstate waters, and territorial seas. Likewise, in categorically
                excluding ephemeral waters, the agencies in the NWPR cite section
                101(a), but again do not explain how their decision relates to or
                advances the Act's objective. 85 FR 22277, April 21, 2020. In contrast,
                informed by the policy in section 101(b) and the Act's objective in
                section 101(a), the proposed role appropriately distinguishes between
                jurisdictional and non-jurisdictional tributaries based on whether a
                tributary implicates core federal interests, in which case it is
                covered by the rule, or fails to do so, in which case its protection
                and management is left to states and tribes.
                 The NWPR similarly relied upon section 101(b) as a basis for its
                definition of adjacent wetlands, in particular the decision to exclude
                from consideration subsurface hydrologic connection between a wetland
                and an adjacent water when determining jurisdiction, stating:
                ``[B]alancing the policy in CWA section 101(a) with the limitations on
                federal authority embodied in CWA section 101(b), the agencies are
                finalizing the definition of `adjacent wetlands' that does not include
                subsurface hydrologic connectivity as a basis for determining
                adjacency.'' Id. at 22313. Again, the NWPR does not explain how
                excluding consideration of subsurface hydrologic connections relates to
                or derives from section 101(b), and the agencies do not now discern
                such a linkage. And as with the definition of tributaries, the NWPR
                does not explain how this choice relates to or advances the objective
                of the Act. In contrast, the proposed rule's approach to adjacent
                wetlands, like its approach to jurisdictional tributaries, gives due
                consideration to the policy in section 101(b) and the objective in
                section 101(a) by tethering jurisdiction to whether the wetland
                implicates foundational waters with a demonstrated federal interest.
                4. The Proposed Rule Is Both Familiar and Implementable
                 The agencies have extensive experience implementing the 1986
                regulations. In addition, the scientific and technical information
                available to inform the significant nexus analysis and identify waters
                that meet the relatively permanent standard has markedly improved over
                time and become more easily available since the agencies first started
                implementing both standards. The agencies are taking comment on a range
                of implementation options discussed in section V.D of this preamble
                that would further inform the public as to the agencies' intended
                practice for asserting jurisdiction under the proposed rule.
                 Since the Court's decision in Rapanos, the agencies have gained
                more than a decade of experience implementing the 1986 regulations
                consistent with the relatively permanent standard and the significant
                nexus standard under three different presidential Administrations,
                beginning with the Rapanos Guidance issued in 2007. Even after the
                agencies promulgated the 2015 Clean Water Rule, they continued to
                implement the 1986 regulations consistent with the Rapanos Guidance in
                certain states in response to court decisions enjoining the 2015 Clean
                Water Rule in various parts of the country.
                 The agencies repromulgated the 1986 regulations in the 2019 Repeal
                Rule and implemented those rules nationwide until June 22, 2020, when
                the NWPR became effective. The agencies explained that with the 2019
                Repeal Rule, they intended to ``restore the regulatory text that
                existed prior to the 2015 Rule'' and that the agencies would
                ``implement the pre-2015 Rule regulations informed by applicable agency
                guidance documents and consistent with Supreme Court decisions and
                longstanding agency practice.'' 84 FR 56626, October 22, 2019. The
                agencies concluded that ``[the] final rule will provide greater
                regulatory certainty and national consistency while the agencies
                consider public comments on the proposed [2020 Rule].'' Id. at 56660.
                To further justify a return to the 1986 framework, the agencies noted
                that ``[t]he agencies, their
                [[Page 69405]]
                coregulators, and the regulated community are . . . familiar with the
                pre-2015 Rule regulatory regime and have amassed significant experience
                operating under those pre-existing regulations. Agency staff in
                particular have developed significant technical expertise in
                implementing the 1986 regulations.'' Id. The 2019 Repeal Rule would
                thus ``provide greater certainty by reinstating nationwide a
                longstanding regulatory framework that is familiar to and well
                understood by the agencies, States, Tribes, local governments,
                regulated entities, and the public.'' Id. at 56661. Indeed, a number of
                regulators and regulated parties alike expressed support for returning
                to the pre-2015 regulations, as implemented following SWANCC and
                Rapanos, due in part to their experience and familiarity with that
                regime.\29\
                ---------------------------------------------------------------------------
                 \29\ See, e.g., comments submitted by American Water Works
                Association (August 13, 2018) (Docket ID: EPA-HQ-OW-2017-0203-
                15559); comments submitted by North Dakota's Department of
                Agriculture (July 25, 2018) (Docket ID: EPA-HQ-OW-2017-0203-15541);
                comments submitted by the Office of the Governor of Utah (August 9,
                2018) (Docket ID: EPA-HQ-OW-2017-0203-15202) (``Recodification of
                the regulations that existed prior to the 2015 Rule will provide
                continuity and certainty for regulated entities, States, the
                agencies' staff, and the American public.'').
                ---------------------------------------------------------------------------
                 Further, in responding to comments asserting that the agencies
                should not return to the pre-2015 regulatory regime because that regime
                would reduce regulatory certainty compared to the 2015 Clean Water Rule
                due to the prior regime's reliance on case-specific significant nexus
                determinations, the agencies explained that ``[f]ollowing the Supreme
                Court's decisions in SWANCC and Rapanos . . . the Corps published a
                guidebook to assist district staff in issuing approved jurisdictional
                determinations. In particular, the guidebook outlines procedures and
                documentation used to support significant nexus determinations. This
                guidebook has been and continues to be publicly available and will
                continue to serve as a resource in issuing jurisdictional
                determinations under this final rule.'' \30\ Id. at 56660. Even after
                the NWPR's June 22, 2020 effective date, the agencies continued to
                implement the 2019 Repeal Rule consistent with the Rapanos Guidance in
                Colorado until April 2021 due to litigation barring implementation of
                the NWPR in that state.
                ---------------------------------------------------------------------------
                 \30\ For convenience, EPA decisions on jurisdiction are referred
                to as jurisdictional determinations throughout this document, but
                such decisions are not approved jurisdictional determinations as
                defined and governed by the Corps regulations at 33 CFR 331.2.
                ---------------------------------------------------------------------------
                 In addition to the past three presidential Administrations, courts
                have also found that the 1986 regulations, implemented consistent with
                the Rapanos standards, provide an appropriate regulatory framework by
                which to implement the Act. Indeed, in staying the 2015 Rule
                nationwide, the Sixth Circuit found that returning to the ``familiar,
                if imperfect, pre-Rule regime'' was the best path forward pending
                judicial review of the 2015 Rule. In re EPA & Dep't of Def. Final Rule,
                803 F.3d 804, 808 (6th Cir. 2015). In doing so, the court recognized
                that it needed to reinstate the pre-2015 regulatory regime--not the
                1986 regulations alone--to properly preserve the status quo. See id. at
                806 (finding that ``the status quo at issue is the pre-[2015 Rule]
                regime of federal-state collaboration that has been in place for
                several years, following the Supreme Court's decision in Rapanos'').
                Likewise, in vacating the NWPR, the Arizona district court reinstated
                the pre-2015 regulatory regime, noting that the regime ``is familiar to
                the Agencies and industry alike.'' See Pascua Yaqui Tribe, 2021 WL
                3855977, at *5.
                 The agencies acknowledge that a return to the pre-2015 regime would
                result in the need for case-specific analyses for certain
                jurisdictional determinations, potentially raising some timeliness and
                consistency issues that the agencies' rules in 2015 and 2020 were
                designed, in part, to reduce. However, the NWPR both fails to advance
                the Act's statutory objective and introduces new implementation
                uncertainties, including its own case-specific typical year analysis
                for most categories of jurisdictional waters. In contrast, the proposed
                rule is both consistent with the Act's statutory text and purposes and
                is longstanding and familiar to regulated parties and regulators alike.
                Moreover, all definitions of ``waters of the United States'' require
                some level of case-specific analysis, and implementation of the
                proposed rule will be aided by improved and increased scientific and
                technical information and tools that both the agencies and the public
                can use to determine whether waters are ``waters of the United States''
                (see section V.D of this preamble). Accordingly, the agencies have
                concluded the proposed rule is consistent with the Clean Water Act and
                the best available science as well as familiar and implementable.
                 Through the various rulemakings and court decisions relating to the
                definition of ``waters of the United States'' since the Rapanos
                decision in 2006, the agencies have continued implementing the 1986
                regulations consistent with the Rapanos standards nationwide or in
                numerous states across the country for various periods of time. This
                experience has allowed the agencies to further develop expertise in
                implementing this regime. The agencies, most often the Corps, have made
                hundreds of thousands of Clean Water Act approved jurisdictional
                determinations since the issuance of the 2008 Rapanos Guidance. Of
                those, approximately 36,000 have required a case-specific significant
                nexus determination. The agencies have made such determinations in
                every state in the country as well as in the U.S. territories.
                 With field staff located in 38 Corps District offices and 10 EPA
                regional offices, the agencies have over a decade of nationwide
                experience in making decisions regarding jurisdiction under the 1986
                regulations consistent with the relatively permanent standard and the
                significant nexus standard as interpreted by the Rapanos Guidance.
                These individual determinations have been made affirmatively for waters
                ranging from an ephemeral stream that flows directly into a traditional
                navigable water used extensively for recreational boating and fishing,
                to wetlands directly touching a perennial tributary, to an intermittent
                stream that provides flow to a drinking water source, to a group of
                floodplain wetlands that provide important protection from floodwaters
                to downstream communities alongside the traditional navigable water, to
                headwater mountain streams that provide high quality water that
                supplies baseflow and reduces the harmful concentrations of pollutants
                in the main part of the river below. The agencies have also made many
                findings of no jurisdiction under the 1986 regulations when they
                concluded the waters in question did not meet either the relatively
                permanent standard or the significant nexus standard as implemented by
                the Rapanos Guidance. This includes individual determinations for a
                small non-relatively permanent stream without any adjacent wetlands
                miles from the nearest downstream traditional navigable water, for a
                small wetland adjacent to a non-relatively permanent water that
                together did not have a case specific significant nexus under the
                guidance, and for a roadside ditch constructed in and draining uplands
                that lacked relatively permanent flow.
                 Through this experience, the agencies developed wide-ranging
                technical expertise in assessing the hydrologic flowpaths along which
                water and materials are transported and transformed that determine the
                degree of chemical, physical, or biological connectivity and effects to
                downstream
                [[Page 69406]]
                waters. The agencies have also become deeply familiar with the
                variations in climate, geology, and terrain within and among watersheds
                and over time that affect the functions (such as the removal or
                transformation of pollutants) performed by streams, open waters, and
                wetlands for downstream traditional navigable waters, interstate
                waters, or the territorial seas. The Corps can complete jurisdictional
                determinations at no charge to the landowner or project proponent upon
                their request.
                 The agencies utilize many tools and many sources of information to
                help support decisions on jurisdiction, including U.S. Geological
                Survey (USGS) and state and local topographic maps, aerial photography,
                satellite imagery, soil surveys, National Wetland Inventory maps,
                floodplain maps, watershed studies, scientific literature and
                references, and field work. As discussed further in section V.D.3.d of
                this preamble, these tools have undergone significant technological
                advances, and become increasingly available, since the Rapanos
                decision. For example, USGS and state and local stream maps and
                datasets, aerial photography, gage data, watershed assessments,
                monitoring data, and field observations are often used to help assess
                the contributions of flow of tributaries, including intermittent and
                ephemeral streams, to downstream traditional navigable waters,
                interstate waters, or the territorial seas. Similarly, floodplain and
                topographic maps from federal, state, and local agencies, modeling
                tools, and field observations can be used to assess how wetlands are
                storing floodwaters that might otherwise affect the integrity of
                downstream waters. Further, the agencies utilize the large body of
                scientific literature regarding the functions of tributaries, including
                tributaries with ephemeral, intermittent, and perennial flow, and of
                wetlands and open waters to inform their significant nexus analyses. In
                addition, the agencies have experience and expertise from decades of
                making decisions on jurisdiction that considered hydrology, ordinary
                high water mark (OHWM) and its associated indicators (see section
                V.C.9.d of this preamble), biota, and other technical factors in
                implementing Clean Water Act programs. The agencies' immersion in the
                science, along with the practical expertise developed through case-
                specific determinations across the country for more than a decade, have
                helped the agencies determine which waters have a significant nexus and
                where to draw boundaries demarking the ``waters of the United States.''
                 Regulated entities and other interested parties also have
                significant experience with the 1986 regulations and the two Rapanos
                standards. While the agencies have been developing their expertise in
                implementing this regime, so have state and tribal co-regulators and
                regulated entities that may be subject to the Act's reach, including
                technical consultants that advise regulated entities on whether they
                may be subject to Clean Water Act requirements, and interested citizens
                who may play an important role in the Act's permitting process.
                 Due in part to the familiarity of this regime, the proposed rule
                would not undermine significant reliance interests in an alternative
                regime, including the NWPR. The Supreme Court has held that agencies'
                changes in position do not require any reasons ``more substantial than
                those required to adopt a policy in the first instance.'' FCC v. Fox
                Television Stations, Inc., 556 U.S. 502, 514 (U.S. 2009). The Court
                acknowledges that if an agency's ``prior policy has engendered serious
                reliance interests,'' the agencies must not ignore them, but must
                provide a reasoned explanation for disregarding facts and circumstances
                that underlay or were engendered by the prior policy. Id. at 515.
                However, the Court emphasizes that even in the case of serious reliance
                interests, further justification is not required ``by the mere fact of
                policy change.'' Id. at 516.
                 The proposal does not implicate serious reliance interests because,
                first, the agencies are proposing to codify a rule similar to the
                definition currently being implemented nationwide. Therefore, no
                stakeholders are currently relying on the implementation of an
                alternative definition, including the NWPR. As discussed in section VI
                of this preamble, the proposed rule would restore a regime that is
                generally comparable to current practice, and there would be no
                appreciable cost or benefit difference between the proposed rule and
                the regulatory regime that the agencies are currently implementing.
                Second, members of the public, states, and tribes have been aware that
                the agencies might reconsider the NWPR for nearly a year and have had
                many opportunities to share their views with the agencies. President
                Biden indicated on his first day in office, following the issuance of
                Executive Order 13990, that this administration would be reviewing the
                NWPR and deciding whether to revise or replace the rule. See section
                IV.B.5 of this preamble. On June 9, 2021, the agencies announced their
                intention to revise or replace the rule. The agencies subsequently
                embarked on an extensive stakeholder outreach process, including public
                meetings and state and tribal consultation. See section IV.C of this
                preamble. The agencies received over 32,000 recommendation letters from
                the public during its pre-proposal outreach. Third, the NWPR was only
                in effect for 14 months and was subject to multiple legal challenges
                during that entire time. Finally, as discussed in this section, members
                of the public are familiar with the proposed rule's regulatory
                framework thereby minimizing the potential disruption of a change.
                Regardless, even if serious reliance interests were at issue, which
                they are not, this proposed rule provides a thorough and reasoned
                explanation for the changed definition of ``waters of the United
                States.''
                 For all of these reasons, the agencies are now once again proposing
                to return the definition of ``waters of the United States'' to its
                longstanding and familiar definition reflected in the 1986 regulations,
                amended to reflect the agencies' current view of the limitations on
                their jurisdiction informed by relevant Supreme Court decisions.
                B. Concerns With Alternatives
                 In promulgating a rule to repeal existing regulations, agencies
                must address and consider alternative ways of achieving the relevant
                statute's objectives and must provide adequate reasons to abandon those
                alternatives. Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins.
                Co., 463 U.S. 29, 48 (1983). As discussed below, the agencies have
                thoroughly considered alternatives to the proposed rule and have
                concluded that the proposed rule is the best path forward to meet the
                agencies' goals to promulgate a rule that advances the objective of the
                Clean Water Act, is consistent with Supreme Court decisions, is
                supported by the best available science, and promptly and durably
                restores vital protections to the nation's waters. The agencies have
                reconsidered the policies, interpretations, and conclusions of the NWPR
                and for the reasons articulated in this preamble are changing their
                approach. FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515
                (2009).
                1. 2015 Clean Water Rule
                 The agencies are not proposing to repromulgate the 2015 Clean Water
                Rule. While the proposed rule utilizes the best available science in
                support of the conclusion that the proposed rule would advance the
                objectives of the Act, the proposed rule is not, as aspects of the 2015
                Rule were, based on categorical significant nexus determinations.
                Rather, the proposed rule restores the
                [[Page 69407]]
                longstanding and familiar categories of the 1986 regulations and
                proposes jurisdictional limitations based on both the relatively
                permanent standard and the significant nexus standard.
                 The 2015 Clean Water Rule, while designed to advance the objective
                of the Clean Water Act, is not the best alternative to meet the policy
                goals of the agencies: To promptly restore the protections of the
                longstanding regulations and avoid current and future harms to
                important aquatic resources, consistent with the best available science
                and the agencies' determination of the statutory limits on the scope of
                the ``waters of the United States.'' In particular, the procedural
                status of the 2015 Rule in light of the complex litigation surrounding
                it means that re-adoption of the rule would not meet the agencies'
                policy goal of promptly ensuring necessary protections for the nation's
                waters.
                 Indeed, litigation over the 2015 Rule previously led to different
                definitions of ``waters of the United States'' being in effect in
                different parts of the country. At this time, the 2015 Clean Water Rule
                remains subject to preliminary injunctions barring implementation of
                the rule in roughly half the states in the country. See section I.A of
                the Technical Support Document for more information on the status of
                the definition of ``waters of the United States'' in effect at
                different times across the country based on the litigation over the
                2015 Rule.
                2. 2019 Repeal Rule
                 As discussed in section V.A of this preamble, the agencies agree
                with the concept in the 2019 Repeal Rule of returning to the pre-2015
                regulatory framework as a means of restoring a longstanding and
                familiar regulatory regime. Indeed, like the 2019 Repeal Rule, the
                proposed rule seeks to return generally to the longstanding regulations
                that existed prior to the 2015 Clean Water Rule.\31\ Unlike the 2019
                Repeal Rule, however, the proposed rule would restore those regulations
                with necessary limitations to ensure the definition of ``waters of the
                United States'' reflects consideration of the agencies' statutory
                authority under the Clean Water Act and of relevant Supreme Court
                decisions.
                ---------------------------------------------------------------------------
                 \31\ 2019 Repeal Rule, Response to Comments at 9 (``The agencies
                find that reinstating the longstanding and familiar pre-2015 Rule
                regulatory regime will provide regulatory certainty in this interim
                period . . . .''), 15 (``[T]his final rule to recodify the 1986
                regulations will provide greater regulatory certainty and nationwide
                consistency while the agencies consider public comments on the
                proposed revised definition of ``waters of the United States.'').
                ---------------------------------------------------------------------------
                 Additionally, the agencies have significant concerns regarding the
                legal rationale underpinning the 2019 Repeal Rule. In particular, the
                agencies are concerned that the interpretation of relevant Supreme
                Court case law in the 2019 Repeal Rule is flawed and thereby led to an
                erroneous assessment of the legality of the 2015 Clean Water Rule. See,
                e.g., 84 FR 56638-52, October 22, 2019. The agencies' reading of the
                Clean Water Act in the 2019 Repeal Rule is also inconsistent with the
                agencies' considered interpretation, at this time, of the Act. For
                these reasons, the agencies find that the 2019 Repeal Rule is not an
                appropriate alternative to the proposed rule.
                3. NWPR
                 The agencies have also evaluated the NWPR as an alternative to the
                proposed rule. After carefully considering the NWPR in light of the
                text, objective, and legislative history of the Act, Supreme Court case
                law, the best available scientific information, and the agencies'
                experience in implementing the NWPR for over a year, the agencies do
                not believe the NWPR is a suitable alternative to the proposal.
                a. The NWPR Fails To Advance the Objective of the Clean Water Act
                 The agencies do not consider the NWPR to have advanced the
                statutory objective of the Clean Water Act, which the Supreme Court
                recently emphasized is an important aspect of defining the
                jurisdictional scope of the Act. See, e.g., Maui, 140 S. Ct. 1462,
                1468-69 (emphasizing the importance of considering the Clean Water
                Act's objective when determining the scope of the Act and finding that
                ``[t]he Act's provisions use specific definitional language to achieve
                this result,'' including the phrase ``navigable waters''). Consistent
                with the Supreme Court's opinion in Maui, a rule defining ``waters of
                the United States'' must consider its effects on the chemical,
                physical, and biological integrity of the nation's waters. And--as the
                text and structure of the Act, supported by legislative history and
                Supreme Court decisions, make clear--chemical, physical, and biological
                integrity refers to water quality.
                 The agencies do not view the objective of the Clean Water Act as
                the only factor relevant to determining the scope of the Act. Rather,
                the agencies have concluded that consistent with the text, structure,
                and legislative history of the Act, as well as Maui and the other
                Supreme Court decisions addressing ``waters of the United States,'' and
                with general principles of administrative law, the agencies must give
                substantial consideration of the effects of a revised definition of
                ``waters of the United States'' on the integrity of the nation's
                waters.
                 The agencies view the failure of the NWPR to advance the Act's
                objective as an important factor in their choice not to propose a rule
                based on the NWPR. One critical example of the NWPR's failure to
                advance the objective of the Act is its removal of the significant
                nexus test without considering an alternative approach to protecting
                waters that significantly affect downstream traditional navigable
                waters. The significant nexus inquiry reflects and furthers the
                objective of the Clean Water Act by allowing for a scientific
                evaluation of the effect of wetlands, tributaries, and other features
                on downstream waters. For that reason, evolving forms of this inquiry
                have been present in Riverside Bayview, SWANCC, and Justice Kennedy's
                concurring opinion in Rapanos. The NWPR ``eliminate[d]'' the
                significant nexus test, 85 FR 22325, April 21, 2020, and failed to
                replace it with an alternative approach that furthered the objective of
                the Act.
                 To be clear, the Supreme Court's interpretations of the scope of
                ``waters of the United States'' do not require adoption of a
                significant nexus test. The Supreme Court has held that its
                interpretation of a statutory term only binds the agency in future
                rulemakings if it has stated that ``its construction follows from the
                unambiguous terms of the statute and thus leaves no room for agency
                discretion.'' Brand X internet Services, 545 U.S. at 982. The term
                ``waters of the United States'' is no such ``unambiguous term.''
                ``Waters of the United States'' can be subject to many interpretations
                and the agencies have ``generous leeway'' in interpreting it. Rapanos,
                547 U.S. at 758 (Roberts, C.J., concurring in the judgment.)
                 While the agencies were not bound to adopt the significant nexus
                standard, the failure of the NWPR to adopt any standard for
                jurisdiction that adequately addresses the effects of degradation of
                upstream waters on downstream waters, including traditional navigable
                waters, fails to advance the Act's objective. For example, the NWPR
                categorically excluded ephemeral features without appropriately
                considering scientific information about their important effects on the
                integrity of downstream traditional navigable waters. In addition, in
                limiting the scope of protected wetlands to those that touch or
                demonstrate evidence of a regular surface water connection to other
                jurisdictional waters, the NWPR failed
                [[Page 69408]]
                to appropriately consider the many effects of other categories of
                wetlands on downstream waters. For example, an ephemeral stream that
                flows directly into the Rio Grande (a traditional navigable water) and
                an adjacent wetland separated from the Mississippi River (a traditional
                navigable water) by an artificial levee and that lacks a direct
                hydrologic surface connection to the river in a typical year are non-
                jurisdictional under the NWPR but have significant effects on
                traditional navigable waters.
                 The NWPR's assertion that it considered the objective of the Act
                because Clean Water Act and non-Clean Water Act state, tribal, and
                local efforts ``collectively pursue the objective'' does not reflect
                consideration of the objective as intended by Congress. The agencies
                contended in adopting the NWPR that the drastic reduction in the scope
                of Clean Water Act jurisdiction pursues the objective of the Act
                because it would be combined with the Clean Water Act's non-regulatory
                programs as well as state, tribal, and local efforts. The NWPR
                explained: ``The CWA's longstanding regulatory permitting programs,
                coupled with the controls that States, Tribes, and local entities
                choose to exercise over their land and water resources, will continue
                to address the discharge of pollutants into waters of the United
                States, and the CWA's non-regulatory measures will continue to address
                pollution of the nation's waters generally. These programs and measures
                collectively pursue the objective of restoring and maintaining the
                chemical, physical, and biological integrity of the nation's waters.''
                85 FR 22269, April 21, 2020.
                 The agencies agree with the NWPR's position that the Clean Water
                Act's non-regulatory measures, such as grantmaking and technical
                assistance authorities, advance the objective the Act. However, the
                agencies do not view these authorities as limiting the scope of
                ``waters of the United States,'' or as relevant to determining whether
                a definition of ``waters of the United States'' advances the objective
                of the Act. The non-regulatory Clean Water Act programs that the NWPR
                cites complement and support the permitting programs at the core of the
                Act, as opposed to limiting its scope. For example, the NWPR cited the
                Act's provisions to address pollution into key waters in its
                discussion, including the Great Lakes, 33 U.S.C. 1258, the Chesapeake
                Bay, see id. at 1267(a)(3), Long Island Sound, see id. at
                1269(c)(2)(D), and Lake Champlain, see id. at 1270(g)(2). These
                resources are ``waters of the United States'' to which regulatory
                programs apply, and the technical assistance and grants in the cited
                sections assist states and others in achieving the requirements of the
                Act, but do not limit the regulatory programs' scope.
                 The agencies disagree, however, with NWPR's assertion that the
                rule's reduction in regulatory scope achieved the objective of the Act
                based in part on the impacts of non-Clean Water Act programs. As
                discussed in section V.A.3.B of this preamble, the Clean Water Act's
                fundamental innovation in 1972 was ``to establish an all-encompassing
                program of water pollution regulation,'' Int'l Paper Co. v. Ouellette,
                479 U.S. 481, 492-93 (1987). The definition of ``waters of the United
                States'' establishes the scope of that program. The agencies therefore
                believe it is appropriate to consider whether the definition of the
                scope of waters to which the Act's water pollution regulations apply
                helps to achieve that objective. Thus, the NWPR's statement that the
                rule ``pursues'' the objective of the Act if Clean Water Act and non-
                Clean Water Act programs are viewed in ``combination,'' is not
                consistent with the better reading of text and structure of the Act,
                its legislative history, or Supreme Court decisions concerning the
                effect of enactment of the Clean Water Act in 1972, nor does it fulfill
                the agencies' obligation to consider the objective of the Act by
                assessing the water quality effects of revising the definition of
                ``waters of the United States.''
                 In sum, based on the text, structure, and history of the statute,
                the relevant and available science, Supreme Court case law, and the
                agencies' technical expertise and experience, the agencies have
                determined that the NWPR is not a suitable alternative to the proposed
                rule because it fails to achieve the objective of the Act. The NWPR
                does not establish either the significant nexus test or an alternative
                standard that advances the objective of the Clean Water Act by
                protecting waters, including upstream ephemeral tributaries and
                wetlands, where they have a significant effect on the integrity of
                downstream traditional navigable waters, interstate waters, and the
                territorial seas and does not appropriately value the importance of
                federal programs in achieving the objective of the Act.
                b. The NWPR is Inconsistent With the Best Available Scientific
                Information
                 The NWPR's exclusion of major categories of waters from the
                protections of the Act, specifically in the definitions of
                ``tributary'' and ``adjacent wetlands,'' runs counter to the scientific
                record demonstrating how such waters can affect the integrity of
                downstream waters. Specifically, its categorical exclusion of ephemeral
                features and large categories of wetlands is inconsistent with the
                scientific record before the agencies. In addition, the NWPR's limits
                on the scope of protected wetlands to those that touch or demonstrate
                evidence of a regular surface water connection to other jurisdictional
                waters were counter to the ample scientific information demonstrating
                the effects of wetlands on downstream waters when they have other types
                of connections.
                 First, the definition of the term ``tributary'' in the NWPR
                categorically excluded ephemeral streams from the regulatory
                protections of the Act, contrary to scientific information emphasizing
                the vital role these streams can play in protecting the integrity of
                downstream waters. The science is clear that aggregate effects of
                ephemeral streams ``can have substantial consequences on the integrity
                of the downstream waters'' and that the evidence of such downstream
                effects is ``strong and compelling,'' as discussed above. Science
                Report at 6-10, 6-13. EPA's SAB Review of the draft Science Report
                explains that ephemeral streams ``are no less important to the
                integrity of the downgradient waters'' than perennial or intermittent
                streams. SAB Review at 22-23, 54 fig. 3. While in the arid Southwest,
                features flow into downstream waters less frequently than they do in
                the wetter East, the Science Report emphasizes that short duration
                flows through ephemeral streams can transport large volumes of water to
                downstream rivers. Science Report at 6-10. For instance, the report
                notes that ephemeral streams supplied 76% of flow to the Rio Grande
                following a large rainstorm. Id. at 3-8. The SAB Review emphasizes that
                the ``cumulative effects'' of ephemeral flows in arid landscapes can be
                ``critical to the maintenance of the chemical, physical, and biological
                integrity'' of downstream waters. SAB Review at 22.
                 Similarly, the NWPR's definition of ``adjacent wetlands'' excluded
                many categories of wetlands that can play a vital role in protecting
                the integrity of waters to which they are connected, including
                traditional navigable waters. In defining ``adjacent wetlands,'' the
                NWPR limited the scope of wetlands protected by the Clean Water Act's
                regulatory programs to those that either abut or have evidence of
                certain surface water connections to other protected waters in a
                typical year. 85 FR 22340, April 21, 2020. Specifically, the rule
                [[Page 69409]]
                encompassed wetlands that (i) abut, meaning to touch, another
                jurisdictional water; (ii) are flooded by a jurisdictional water in a
                typical year; (iii) are separated from a jurisdictional water only by a
                natural feature, such as a berm, which provides evidence of a direct
                surface hydrological connection with that water; or (iv) are separated
                from a jurisdictional water only by an artificial structure so long as
                that structure allows for a direct hydrologic surface connection
                between the wetlands and the water in a typical year. Id. As with the
                tributary definition, the NWPR stated that the definition of ``adjacent
                wetlands'' is ``informed by science.'' Id. at 22314. Yet the NWPR's
                limits on the scope of protected wetlands to those that touch or
                demonstrate evidence of a regular surface water connection to other
                jurisdictional waters were counter to the ample scientific information
                before the agencies demonstrating the effects of wetlands on downstream
                waters when they have other types of surface connections, such as
                wetlands that overflow and flood jurisdictional waters or wetlands with
                less frequent surface water connections due to long-term drought;
                wetlands with shallow subsurface connections to other protected waters;
                or other wetlands proximate to jurisdictional waters. See Rapanos, 547
                U.S. at 786 (Kennedy, J., concurring in the judgment) (``[g]iven the
                role wetlands play in pollutant filtering, flood control, and runoff
                storage, it may well be the absence of a hydrologic connection (in the
                sense of interchange of waters) that shows the wetlands' significance
                for the aquatic system.'') Id. at 786.
                 Indeed, the overwhelming scientific information before the agencies
                weighs decisively against proposing the definition of ``adjacent
                wetlands'' in the NWPR. Available scientific information demonstrates
                the significant effects of categories of newly excluded wetlands on the
                chemical, physical, and biological integrity of downstream traditional
                navigable waters. For example, whereas the NWPR provided that wetlands
                flooded by jurisdictional waters are only protected if the flooding
                occurs in a ``typical year,'' the Science Report stated that wetlands
                that are ``rarely'' or ``infrequently'' flooded by streams and rivers
                can be ``highly connected'' to those waters and have ``long-lasting
                effects'' on them. Science Report at 4-39. The Science Report noted
                that effects ``critical to maintaining the health of the river'' result
                from large floods that provide ``infrequent connections'' with more
                distant wetlands. Id. Reflecting these concerns, the October 16, 2019
                SAB Draft Commentary on the proposed NWPR stated that the narrow
                definition of ``adjacent wetlands'' in the NWPR as it was proposed
                ``departs from established science.'' The agencies have weighed these
                statements and in light of the information about the importance of
                ``infrequently'' flooded wetlands to downstream waters, the agencies
                believe that the NWPR's exclusion of wetlands that lack the limited,
                specific types of surface water connections to other jurisdictional
                waters in a typical year lacked scientific support.
                 The SAB's assessment of the NWPR proposal recognized that the
                proposed rule was not consistent with the scientific information in the
                record, including the Draft Science Report that the SAB had previously
                reviewed. SAB Commentary on the Proposed Rule Defining the Scope of
                Waters Federally Regulated Under the Clean Water Act (February 27,
                2020). The 2020 SAB Commentary emphasized that the proposal does not
                ``fully incorporate the body of science on connectivity'' that the SAB
                had reviewed in the Draft Science Report and offers ``no scientific
                justification for disregarding the connectivity of waters accepted by
                current hydrological science.'' Id. at 2.
                 The NWPR stated that the ``agencies' decisions in support of this
                final rule have been informed by science.'' 85 FR 22288, April 21,
                2020. For example, the scientific information that the NWPR cited as a
                basis for excluding ephemeral tributaries is the concept of a
                ``connectivity gradient.'' Id., citing the SAB Review. The NWPR
                referred to the SAB Review's recommendation that the agencies recognize
                that connectivity occurs along a gradient allowing for variation in
                chemical, physical, and biological connections. Id., citing the SAB
                Review at 3. The NWPR asserted that there is a ``decreased'' likelihood
                that waters with ``less than perennial or intermittent'' flow, i.e.,
                ephemeral streams, will affect the chemical, physical, and biological
                integrity of downstream waters. Id.
                 Upon careful review, however, the agencies have concluded that the
                NWPR's conclusion takes the SAB's recommendation out of context and is
                inconsistent with the information in the SAB Review as a whole. The
                agencies recognize that the SAB explained that the connectivity
                gradient the NWPR cited was just a hypothetical example \32\ meant to
                illustrate just one aspect of connectivity--hydrological, or physical
                connectivity--and sheds no light on the many other ways that features
                connect to and affect downstream waters. According to the SAB itself,
                the only scientific information the agencies provided in support of
                categorically excluding ephemeral features does not fully represent the
                discussion in the cited SAB Review and runs counter to key elements of
                the scientific record before the agencies. Id.
                ---------------------------------------------------------------------------
                 \32\ The figure cited is captioned in part as ``Hypothetical
                illustration of connectivity gradient and potential consequences to
                downstream waters.'' SAB Review at 54 (emphasis added). Nowhere in
                its review does the SAB review indicate that this is the actual or
                only connectivity gradient.
                ---------------------------------------------------------------------------
                 The NWPR also stated that the line it draws between regulated and
                non-regulated wetlands, which excludes large categories of wetlands
                previously covered by the Act, is ``informed by science.'' 85 FR 22314,
                April 21, 2020. The NWPR cited statements from the SAB Review to the
                effect that wetlands situated alongside other waters are likely to be
                connected to those waters, whereas ``those connections become less
                obvious'' as the distance ``increases.'' Id., citing the SAB Review at
                55; see also id. at 22314, citing the SAB Review at 60 (``[s]patial
                proximity is one important determinant [influencing the connections]
                between wetlands and downstream waters''). In addition, the NWPR cited
                a statement in the Science Report that explained, ``areas that are
                closer to rivers and streams have a higher probability of being
                connected than areas farther away.'' Id. at 22314, citing the Science
                Report at ES-4.\33\
                 Despite these citations, the NWPR's definition of adjacent is not
                based on proximity, but instead on factors that are distinct from
                proximity--e.g., a ``direct hydrologic connection,'' or a ``continuous
                surface [water] connection.'' See id. at 22340. Thus, the NWPR's
                definition of ``adjacent wetlands'' may exclude wetlands a dozen feet
                away from jurisdictional waters (therefore proximate under any
                reasonable interpretation of the term) if they are separated by a levee
                that does not convey flow in a typical year, but include wetlands much
                further away so long as they are inundated by flooding from the
                jurisdictional water in a typical year.
                c. The NWPR Is Difficult To Implement and Yields Inconsistent Results
                 In addition to the above concerns, the agencies' experience
                implementing the NWPR for over a year made clear that foundational
                concepts underlying much of the NWPR are confusing and difficult to
                implement in the way the NWPR required. While any rule that draws lines
                between jurisdictional waters and
                [[Page 69410]]
                non-jurisdictional waters will involve some implementation challenges,
                the agencies have found the challenges imposed by the NWPR to be
                impracticable in important respects. Based on the agencies' experience,
                the NWPR does not ``provide[] clarity and predictability for Federal
                agencies, States, Tribes, the regulated community, and the public.''
                See 85 FR 22252, April 21, 2020. More importantly, the challenges that
                the NWPR imposes to establish jurisdiction for features that it appears
                to define as jurisdictional and that significantly affect the integrity
                of downstream waters further undermine the NWPR's viability as an
                alternative to the proposed rule.
                i. ``Typical Year'' Metric
                 The ``typical year'' is a concept fundamental to many of the NWPR's
                definitions. Id. at 22273. Under the rule, tributaries and lakes,
                ponds, and impoundments of jurisdictional waters are only
                jurisdictional if they have certain surface water connections with a
                traditional navigable water or territorial sea at least once in a
                typical year. 33 CFR 328.3(c)(6), (12). Two categories of wetlands only
                meet the adjacency test for jurisdiction if they have a surface water
                connection with other jurisdictional waters once in a typical year. Id.
                at (c)(1). As a scientific matter, the concept of ``typical year
                conditions,'' including precipitation normalcy, may be relevant to
                ensuring that certain surface water connections in natural streams are
                not being observed under conditions that are unusually wet or dry. In
                terms of implementation, the concept of precipitation normalcy is valid
                in certain contexts, such as to inform determinations as to the
                presence of a wetland. However, in many important contexts, available
                tools, including the tools the NWPR recommends, cannot reliably
                demonstrate the presence of surface water connections in a typical
                year, which are a necessary element of most categories of
                jurisdictional waters under the NWPR. However, ``typical year
                conditions'' are often irrelevant to the extent of flow in many human-
                altered streams, including effluent-dependent streams, and the NWPR did
                not explain why human-altered hydrology should be subject to the same
                typical year requirement as natural streams. These challenges undermine
                the NWPR's claim that it enhances the ``predictability and consistency
                of Clean Water Act programs . . .'' See 85 FR 22250, April 21, 2020.
                 Identifying the presence of a surface water connection in a typical
                year can be difficult and sometimes impossible, as such connections are
                often not apparent from visual field observation alone. For example, on
                the day of a visit to an intermittent stream that flows only several
                months or several weeks a year, it is very unlikely that an observer
                would see a surface water connection to a downstream jurisdictional
                water. Similarly, though many ponds or wetlands may be frequently
                inundated, those in arid areas may be inundated only a few times every
                year, and sometimes the inundation occurs on a single day or within a
                matter of hours. While these waters satisfy the NWPR's jurisdictional
                test, agency staff would probably not be able to determine that they
                do, given how unlikely they would be to observe it. The difficulty of
                finding in a field visit the direct hydrologic connections under any
                interpretation of typical year permissible under the NWPR is
                exacerbated by the fact that the NWPR discourages reliance on field
                indicators. See, e.g., id. at 22292 (``The agencies . . . conclude that
                physical indicators of flow, absent verification of the actual
                occurrence of flow, may not accurately represent the flow
                classifications required for tributaries under this rule.'').
                 Given the insufficiency of visual field observations to assess the
                presence of a surface water connection as specified in the NWPR, agency
                staff must often expend substantial time and resources to try to obtain
                ancillary data to determine flow conditions at a particular site in a
                typical year. Hydrologic modeling tools and advanced statistical
                analyses could be employed where sufficient flow data are available,
                but often data needed to conduct such an analysis is limited or lacking
                altogether, especially for smaller streams. Few streams across the
                country have hydrologic gages that continuously measure flow, as most
                such gages are located on larger rivers with perennial flow.
                 For the same reasons that agency staff are unlikely to witness the
                specific surface water connections required under the NWPR during a
                site visit in dry regions or during the dry season, available aerial
                photographs, which are often taken just once per year or once every
                other year, are also very unlikely to capture evidence of this surface
                water connection between a stream and a downstream traditional
                navigable water or territorial sea. High-resolution satellite imagery
                can potentially provide additional coverage, but availability and
                usability vary across the country, depending on access, update
                intervals, cloud cover, and land cover (i.e., vegetation or trees that
                obscure aerial views of stream channels, requiring the use of advanced
                tools to detect features of interest or the presence of water).
                Moreover, as the NWPR acknowledges, ``characteristics of tributaries
                may not be visible in aerial photographs'' taken during periods of
                ``high shrub or tree cover,'' 85 FR 22299, April 21, 2020. New
                satellites are expected to surmount some of these issues in the future,
                but as this information is not yet available, regulators could not use
                it to inform jurisdictional decisions under the NWPR. Although any
                definition of ``waters of the United States'' requires the use of
                remote tools like interpretation of aerial or satellite imagery, the
                NWPR made it more challenging to use these resources because of that
                rule's typical year criteria and the burden of proof to demonstrate
                that the requirement is met.
                 The same difficulties create challenges in detecting surface
                hydrologic connections that meet the NWPR's definition of ``adjacent
                wetlands'' or ``lakes and ponds, and impoundments of jurisdictional
                waters.'' Demonstrating that a wetland, lake, pond, or impoundment is
                inundated by flooding once in a typical year would require a field
                visit or a high-quality aerial photograph or satellite image coinciding
                with the exact time that the hydrologic connection (flooding) occurs
                from a tributary to a wetland, lake, pond, or impoundment. The NWPR's
                standard of inundation by flooding in a typical year is not tied to any
                more commonly calculated flood interval, such as flood recurrence
                intervals, and the agencies are not aware of any tool capable of
                collecting the type of inundation data the NWPR requires. Determining
                that inundation by flooding occurs in a typical year is therefore
                extremely difficult, and sometimes impossible. Demonstrating that an
                artificial feature allows for a direct hydrologic surface connection
                between a wetland and a tributary in a typical year poses similar
                obstacles, requiring either auspiciously timed field visits, aerial
                photography, or high-resolution satellite imagery, or data that the
                agencies may not be able to access, such as construction plans or
                operational records for an artificial levee.
                 The NWPR suggests the agencies ``will generally use'' precipitation
                data from the National Oceanic and Atmospheric Administration (NOAA) to
                help determine the presence of a surface water connection in a typical
                year, see 85 FR 22274, April 21, 2020, but the methodology described in
                the NWPR preamble for determining precipitation in a typical year makes
                it difficult to use these data to inform jurisdiction. NOAA
                precipitation totals over the three
                [[Page 69411]]
                months prior to a site observation are compared to precipitation totals
                observed over the preceding 30 years to determine if rainfall was
                wetter than normal, drier than normal, or normal (``typical''). Using
                the methodology in the preamble of the NWPR, only 40% of observations
                over a rolling 30-year period of record are considered ``normal,''
                while 30% of observations are considered to be ``wetter than normal''
                and 30% of observations are considered to be ``drier than normal.'' If
                surface water flow was observed during normal or dry conditions, the
                agencies can have higher confidence that the surface water observations
                represent flow in a ``typical year.'' However, if flow was observed
                during the 30% of conditions that are ``wetter than normal,'' the
                surface water observations do not reveal whether flow would occur
                during a typical year. And if flow was not observed, precipitation data
                from the previous three months do not indicate whether flow might occur
                in that particular water feature under typical year conditions at a
                different point in the year. Therefore, if a site visit is conducted
                when surface water flow is not present, the agencies' suggested
                approach for evaluating whether a feature meets the typical year test
                often does not provide meaningful and relevant information upon which
                the agencies could reasonably rely to make accurate determinations of
                jurisdiction. Under any regulatory regime, the agencies use a weight of
                evidence approach to determine jurisdiction, but the NWPR typical year
                requirement places onerous and in many instances arbitrary constraints
                on the data that can be used as evidence.
                 Use of NOAA precipitation data to assess whether surface water flow
                occurs in a typical year for purposes of the NWPR presents other
                implementation challenges. The data rely on reports from weather
                stations that are sometimes at a different elevation from the site in
                question, or far away from the site, so that their indications as to
                whether precipitation at a given site is normal, wetter than normal, or
                drier than normal can be inaccurate. More importantly, the typical year
                concept as applied to the NWPR does not account for the increasing
                number of recurrent heatwaves, droughts, storms, and other extreme
                weather events in many parts of the country, which can have profound
                impacts on local and regional streamflow. Although the concept of
                ``typical year'' in the NWPR factors in long-term climatic changes over
                time to some degree by considering a thirty-year rolling period of
                data, see 33 CFR 328.3(c)(13), the NWPR does not allow the agencies
                flexibility to consider other time intervals when appropriate to
                reflect effects of a rapidly changing climate, including positive
                trends in temperature, increasing storm events, and extended droughts.
                In response to more rapid recent changes in climate, NOAA has developed
                alternative approaches for estimating climate normals, including
                seasonal averages computed using shorter, annually-updated averaging
                periods for temperature (10-year seasonal average) and total
                precipitation (15-year seasonal average). The rolling thirty-year
                approach to determining typical year in the NWPR does not allow the
                agencies to use these updated methods.
                 The NWPR notes that the agencies can look to sources of information
                other than site visits, aerial photographs, and precipitation data to
                assess whether a feature has surface water flow in a typical year. It
                identifies the Web-based Water-Budget Interactive Modeling Program,
                Climate Analysis for Wetlands Tables, and the Palmer Drought Severity
                Index, 85 FR 22275, April 21, 2020, but all of these only look at
                climate-related conditions generally and have well documented
                limitations. These methods, which provide information useful in many
                other contexts, often do not specifically answer the jurisdictional
                questions established by the NWPR. For example, they do not address
                whether surface water flow might connect a particular stream to a
                downstream traditional navigable water or territorial sea, whether a
                particular wetland is inundated by or connected to a jurisdictional
                water as required under the NWPR, or how uncertainties associated with
                their application at different locations and in different months affect
                the accuracy of condition estimates. Precipitation is an important
                factor but other information is also relevant to streamflow and surface
                water connections in particular waters, including the abundance of and
                contributions of flow from wetlands, upgradient streams, and open
                waters in the watershed, evapotranspiration rates, water withdrawals
                including groundwater pumping, and other climatic conditions. Yet
                collecting this information from a variety of sources and interpreting
                it can be extremely time- and resource-intensive and may require
                special expertise that in many cases may not be feasible given
                available agency staff and resources. While the agencies have
                substantial experience using a weight of evidence approach to determine
                jurisdiction, the ``typical year'' requirement makes it significantly
                more difficult to interpret available data and narrows the scope of
                data that can be used to determine jurisdiction.
                 Finally, the challenges presented by determining the presence of
                surface water flow in a typical year are even greater when evaluating a
                tributary at a distance from the downstream traditional navigable water
                or territorial sea. Even streams that flow perennially or
                intermittently often travel many miles prior to reaching the closest
                traditional navigable water or territorial sea, meaning many downstream
                reaches may need to be assessed. Under the NWPR, any ephemeral reaches
                along that pathway that do not carry surface water flow once in a
                typical year would render all upstream waters non-jurisdictional. Id.
                at 22277. The need to assess lengthy tributary systems pursuant to this
                provision of the rule imposes an extraordinarily high burden of proof
                on the agencies to assess surface water flow in a typical year along
                the flow path, and the longer the pathway, the less feasible the
                analysis.
                ii. Determining Adjacency
                 The NWPR provides that wetlands are ``adjacent'' when they: (1)
                Abut a traditional navigable water or territorial sea; a tributary; or
                a lake, pond, or impoundment of a jurisdictional water; (2) are
                inundated by flooding from one of these waters in a typical year; (3)
                are physically separated from one of these waters only by a natural
                berm, bank, dune, or similar natural feature; or (4) are physically
                separated from one of these waters only by an artificial dike, barrier,
                or similar artificial structure so long as that structure allows for a
                direct hydrologic surface connection between the wetlands and the water
                in a typical year, such as through a culvert, flood or tide gate, pump,
                or similar artificial feature. Id. at 22338; 33 CFR 328.3(c)(1). In
                practice, agency staff have found several of these criteria for
                adjacency extremely difficult to implement in certain circumstances.
                 First, agency staff have found it difficult to distinguish between
                natural and artificial barriers for purposes of determining adjacency.
                The NWPR for the first time establishes separate tests for adjacency
                depending on whether the barrier between the wetland and jurisdictional
                water is ``natural'' or ``artificial''; if a barrier is artificial, it
                must allow for a direct hydrological surface connection in a typical
                year in order for a wetland to be adjacent, whereas no such showing is
                necessary for natural barriers. 33 CFR 328.3(c)(1)(iv). However, many
                barriers between wetlands and jurisdictional
                [[Page 69412]]
                waters were built decades or even a century earlier, and determining
                whether they were originally natural or artificial can be extremely
                challenging, even if inspected in person, as artificial features that
                are left alone often naturalize over time. It sometimes requires
                extensive research into historical records, and those records may not
                be available at all. Furthermore, some barriers may be both artificial
                and natural. Artificial levees and other barriers are frequently built
                on top of natural berms. Given the distinct regulatory consequences
                that flow from whether a barrier is ``artificial'' or ``natural,'' the
                NWPR requires the agencies to make determinations that are difficult or
                in some cases not possible.
                 The artificial barrier provision also leads to absurd results. For
                example, under the fourth way to meet the adjacency definition, a
                wetland may be jurisdictional if it is separated from a jurisdictional
                water by an artificial structure, such as a levee, that allows for a
                direct hydrologic surface connection in a typical year through a
                culvert. However, the same wetland would not be jurisdictional if there
                was no levee present, even if there was a direct hydrological surface
                connection in a typical year through a culvert (assuming the wetland
                did not meet another criterion for adjacency). The NWPR therefore
                establishes that certain wetlands with a direct hydrologic surface
                connection to a jurisdictional water are only jurisdictional due to the
                presence of an artificial barrier. This discrepancy bears no
                relationship to the actual connections between the features at issue
                and makes no scientific or practical sense.
                 Finally, the provision establishing that a wetland is ``adjacent''
                if a jurisdictional water inundates it by flooding in a typical year is
                also extremely difficult to implement. See 33 CFR 328.3(c)(1)(ii).
                Inundation by flooding in a typical year is not a metric that is
                normally recorded either by implementing agencies or the regulated
                community. Available models generally focus on flood recurrence
                intervals, which do not necessarily correspond to the likelihood of
                inundation by flooding in a given or typical year. Indeed, the NWPR
                acknowledges that inundation by flooding in a typical year could
                correspond to a variety of flood recurrence intervals depending on
                location, climate, season, and other factors. 85 FR 22311, April 21,
                2020. Given the absence of existing records of inundation by flooding,
                determining whether inundation by flooding has occurred in a typical
                year is extremely difficult in many circumstances.
                 Compounding the challenge, the NWPR provides that wetlands can be
                jurisdictional if they are inundated by flooding from a jurisdictional
                water in a typical year--but inundation in the other direction, from
                the wetlands to the jurisdictional water, is not grounds for
                jurisdiction. Not only is there no compelling scientific or legal basis
                for distinguishing between inundation of the wetland as opposed to
                inundation from the wetland, see Riverside Bayview, 474 U.S. at 134
                (upholding the Corps' assertion of jurisdiction over ``wetlands that
                are not flooded by adjacent waters [but] may still tend to drain into
                those waters''), but determining whether the limited available
                photographs or other evidence of inundation reflects flooding in one
                direction as opposed to another compounds the difficulty in evaluating
                whether this standard is met. The same challenges apply to determining
                whether lakes, ponds, or impoundments of jurisdictional waters are
                inundated by flooding in a typical year, one basis for demonstrating
                Clean Water Act jurisdiction over these features. 85 FR 22338, April
                21, 2020; 33 CFR 328.3(c)(vi).
                iii. Ditches
                 Among other requirements, the NWPR provides that a ditch \34\ is
                jurisdictional as a tributary if it was originally built in a tributary
                or adjacent wetland, as those terms are defined in the NWPR, and
                emphasizes that the agencies bear the burden of proof to determine that
                a ditch was originally constructed in a tributary or adjacent wetland.
                33 CFR 328.3(a)(2), (c)(12); 85 FR 22299, April 21, 2020. In other
                words, in order to find a ditch jurisdictional, the agencies must
                demonstrate that a ditch was (1) originally constructed in a stream (2)
                that, at the time of construction, had perennial or intermittent flow
                and (3) a surface water connection to a downstream traditional
                navigable water or territorial sea (4) in a ``typical year.''
                Alternatively, the agencies must show that a ditch was (1) originally
                constructed in a wetland (2) that either abutted or had certain surface
                hydrologic connections to a jurisdictional water (3) in a ``typical
                year,'' in order to demonstrate that the ditch is jurisdictional.
                Americans have been building ditches, straightening streams, and
                draining wetlands for hundreds of years. Therefore, to determine
                whether a ditch is jurisdictional under the NWPR, the agencies must
                address all of the implementation challenges discussed in the preceding
                sections involved in determining surface water connections and wetland
                adjacency in a typical year--but often for ditches built fifty, one
                hundred, or several hundred years ago. To the extent that sparse
                evidence is available to demonstrate a surface water connection in a
                typical year for tributaries using tools available today, evidence is
                even more difficult to find when looking so far back in time. States
                have approached the agencies seeking assistance in assessing the
                jurisdictional status of ditches, but the agencies are often unable to
                provide significant help given the burdens imposed by the NWPR's ditch
                definition.
                ---------------------------------------------------------------------------
                 \34\ Ditches perform many of the same functions as natural
                tributaries. For example, like natural tributaries, ditches that are
                part of the stream network convey water that carries nutrients,
                pollutants, and other constituents, both good and bad, to downstream
                traditional navigable waters, interstate waters, and the territorial
                seas.
                ---------------------------------------------------------------------------
                 The NWPR also provides that ditches are jurisdictional if they
                relocate a tributary, as that term is defined in the rule, 85 FR 22341,
                April 21, 2020, 33 CFR 328.3(a)(2), (c)(12), but this standard as
                defined is also often extremely difficult to assess. The NWPR explains
                that a relocated tributary is ``one in which an entire portion of the
                tributary may be moved to a different location.'' 85 FR 22290, April
                21, 2020. In other words, the NWPR appears to require a ditch to divert
                100% of the tributary's flow to meet the ``relocate a tributary'' test.
                While prior rules have defined relocated tributaries as jurisdictional,
                the requirement that the entire portion be relocated is new and has
                created significant implementation challenges. As a practical matter,
                when a tributary is relocated it often reroutes just a portion to the
                ditch. Assessing whether a ditch relocated 100% of a tributary's flow,
                however, as opposed to 80% or 50% of its flow, is extremely difficult
                and may not be possible in some circumstances. By establishing a
                jurisdictional standard that is extremely difficult to meet, the NWPR
                effectively removes from the protections of the Clean Water Act large
                numbers of ditches that function as tributaries and that significantly
                affect the integrity of downstream traditional navigable waters,
                interstate waters, and the territorial seas. As is the case with
                tributaries, lakes and ponds, impoundments, and wetlands, the NWPR's
                impracticable approach to ditches makes it extremely difficult to find
                that many waters subject to the NWPR are actually jurisdictional,
                further undermining the viability of the
                [[Page 69413]]
                NWPR as an alternative to the proposed rule.
                d. The NWPR Has Significantly Reduced Clean Water Act Protections Over
                Waters
                 The failure of the NWPR to achieve the objective of the Act, as
                well as its inconsistency with science and the challenges it presents
                in implementation, have had real-world consequences. The agencies have
                found that substantially fewer waters are protected by the Clean Water
                Act under the NWPR compared to previous rules and practices. It is
                important to note that the definition of ``waters of the United
                States'' affects most Clean Water Act programs designed to restore and
                maintain water quality--including not only the NPDES and dredged and
                fill permitting programs, but water quality standards, impaired waters
                and total maximum daily loads, oil spill prevention, preparedness and
                response programs, and the state and tribal water quality certification
                programs--because such programs apply only to ``waters of the United
                States.'' While the NWPR was enacted with the expressed intent to
                decrease the scope of federal jurisdiction, the agencies now believe
                the actual decrease in water resource protections has been more
                pronounced than the qualitative predictions in the NWPR preamble and
                supporting documents anticipated and acknowledged to the public. This
                data supports the agencies' conclusion that the NWPR is not a suitable
                alternative to the proposed rule.
                i. Jurisdictional Determination and Permitting Data Show a Large Drop
                in the Scope of Waters Protected Under the Clean Water Act.
                 Through an evaluation of jurisdictional determinations completed by
                the Corps between 2016 and 2021,\35\ EPA and the Army have identified
                consistent indicators of a substantial reduction in waters protected by
                the NWPR (see Technical Support Document section III.B.ii for
                additional discussion on methods and results of the agencies'
                analyses). These indicators include an increase in the number and
                proportion of jurisdictional determinations completed where aquatic
                resources were found to be non-jurisdictional, an increase in
                determinations made by the Corps that no Clean Water Act section 404
                permit is required for specific projects, and an increase in requests
                for the Corps to complete approved jurisdictional determinations (AJDs)
                rather than preliminary jurisdictional determinations (PJDs), which
                treat a feature as jurisdictional. These trends all reflect the narrow
                scope of jurisdiction in the NWPR's definitions. Additionally, the
                agencies believe these indicators account for only a fraction of the
                NWPR's impacts, because many project proponents do not need to seek any
                form of jurisdictional determinations for waters that the NWPR
                categorically excludes, such as ephemeral streams, and the Corps does
                not have purview over such projects and does not track them. A closer
                look at each of these indicators will help demonstrate some of the more
                pronounced impacts of the NWPR on foundational waters of this country
                than was identified for the public in the NWPR and its supporting
                documents. As explained in detail above, when a water falls outside the
                scope of the Act, that means, among other things, that no federal water
                quality standards will be established, and no federal permit will be
                required to control the discharge of pollutants or fill into such
                waters. And by virtue of the fact that the NWPR's scope means that for
                many waters entities do not even need to seek a jurisdictional
                determination, it is impossible to fully understand the scope of
                degradation to foundational waters caused by the NWPR's definition.
                ---------------------------------------------------------------------------
                 \35\ A jurisdictional determination is a written Corps
                determination that a water is subject to regulatory jurisdiction
                under section 404 of the Clean Water Act (33 U.S.C. 1344) or a
                written determination that a water is subject to regulatory
                jurisdiction under section 9 or 10 of the Rivers and Harbors Act of
                1899 (33 U.S.C. 401 et seq.). Jurisdictional determinations are
                identified as either preliminary or approved, and both types are
                recorded in determinations through an internal regulatory management
                database, called Operation and Maintenance Business Information
                Link, Regulatory Module (ORM2). This database documents Department
                of the Army authorizations under Clean Water Act section 404 and
                Rivers and Harbors Act section 10, including permit application
                processing and jurisdictional determinations. This database does not
                include aquatic resources that are not associated with a
                jurisdictional determination or alternatives to jurisdictional
                determinations (such as delineation concurrences or ``No
                jurisdictional determination required'' findings, where the Corps
                finds that a jurisdictional determination is not needed for a
                project), or permit request or resource impacts that are not
                associated with a Corps permit or enforcement action. An approved
                jurisdictional determination (AJD) is an official Corps document
                stating the presence or absence of ``waters of the United States''
                on a parcel or a written statement and map identifying the limits of
                ``waters of the United States'' on a parcel. A preliminary
                jurisdictional determination (PJD) is a non-binding written
                indication that there may be ``waters of the United States'' on a
                parcel; an applicant can elect to use a PJD to voluntarily waive or
                set aside questions regarding Clean Water Act jurisdiction over a
                particular site and thus move forward assuming all waters will be
                treated as jurisdictional without making a formal determination.
                ---------------------------------------------------------------------------
                 Consistent with Executive Order 13990, EPA and Army staff have
                reviewed jurisdictional determinations as recorded in the Corps'
                internal regulatory management database, referred to as the ORM2
                database (see supra note 30), to identify any noticeable trends in
                jurisdictional determinations under the past recent rules defining
                ``waters of the United States.'' The agencies found within the AJDs
                completed under the NWPR, the probability of finding resources to be
                non-jurisdictional also increased precipitously. Of the 9,399 AJDs
                completed by the Corps during the first twelve months in which the NWPR
                was in effect,\36\ the agencies found approximately 75% of AJDs
                completed had identified non-jurisdictional water resources and
                approximately 25% of AJDs completed identified jurisdictional
                waters.\37\ Conversely, when the 1986 regulations and applicable
                guidance were in effect during the previous five years (including
                following the 2019 recodification of those regulations), significantly
                more jurisdictional waters were identified in AJDs than compared to the
                first twelve months of the NWPR. During similar 1-year calendar
                intervals when the 1986 regulations and applicable guidance were in
                effect, approximately 27% to 45% of AJDs completed identified non-
                jurisdictional aquatic resources, with percentages varying between each
                of the different periods, and 55% to 72% of AJDs identified
                jurisdictional resources.\38\
                [[Page 69414]]
                The change from a range of 27% to 45% non-jurisdictional AJD findings
                prior to the NWPR to 75% non-jurisdictional findings following issuance
                of the NWPR indicates that significantly fewer waters are protected by
                the Clean Water Act under the NWPR (see Technical Support Document
                section III.B.ii for additional discussion).
                ---------------------------------------------------------------------------
                 \36\ These AJDs were completed by the Corps between the NWPR's
                effective date of June 22, 2020 and June 21, 2021.
                 \37\ This excludes drylands and waters identified as being
                jurisdictional only under section 10 of the Rivers and Harbors Act.
                In addition, under the NWPR, a single AJD in the Corps' database can
                include both affirmative and negative jurisdictional determinations.
                Under prior regulatory regimes, the Corps' database was structured
                such that a single AJD could be either affirmative, or negative, but
                not both. To account for this change in the structure of the
                database, a NWPR jurisdictional determination that includes both
                affirmative and negative jurisdictional resources was normalized and
                counted as two separate AJDs, one affirmative and one negative. The
                total number of AJDs considered after this process was carried out
                was 9,399. Prior to this normalization, the total number of AJDs
                considered was 7,769. More details on this can be found in the
                Technical Support Document section III.B.ii.
                 \38\ The time periods evaluated were June 22, 2016 to June 21,
                2017; June 22, 2017 to June 21, 2018; and December 23, 2019 to June
                21, 2020. The date ranges here constitute periods of time when the
                1986 regulations (including the 2019 Repeal Rule's recodification of
                those regulations) and applicable guidance were in effect
                nationally. Because the proposed rule is marking a return to prior
                longstanding practice, 2015 Clean Water Rule determinations were
                left out of this analysis.
                ---------------------------------------------------------------------------
                 When evaluating the effect of the NWPR on the number of
                jurisdictional individual aquatic resources (as opposed to the AJDs
                completed), the agencies found a similar significant reduction in
                protections. Within the first twelve months of implementation of the
                NWPR, the Corps documented the jurisdictional status of 48,313
                individual aquatic resources or water features through AJDs completed
                between June 22, 2020, and June 21, 2021; of these individual aquatic
                resources, approximately 75% were found to be non-jurisdictional by the
                Corps. More specifically, 70% of streams and wetlands evaluated were
                found to be non-jurisdictional, including 11,044 ephemeral features
                (mostly streams) and 15,675 wetlands that did not meet the NWPR's
                revised adjacency criteria (and thus are non-jurisdictional under the
                NWPR). Ditches were also frequently found to be non-jurisdictional
                (4,706 individual exclusions), which is likely the result of the
                narrowed definition of a relocated tributary under the NWPR. By
                comparison, only 45% of aquatic resources were found to be non-
                jurisdictional during similar year-long calendar intervals between 2016
                and 2020 under the 1986 regulations implemented consistent with Supreme
                Court case law.\39\ The agencies anticipate that this increase in non-
                jurisdictional determinations, to a level of approximately 75% of water
                bodies being non-jurisdictional under the NWPR as opposed to only 45%
                under the prior regulations, would reduce the integrity of the nation's
                waters.
                ---------------------------------------------------------------------------
                 \39\ Based on the average annual percentage of non-
                jurisdictional findings.
                ---------------------------------------------------------------------------
                 Of particular concern to the agencies is the NWPR's
                disproportionate effect on arid regions of the country, which are
                dominated by ephemeral stream systems. The Corps' data show that in New
                Mexico, of the 263 streams assessed via AJDs in the first twelve months
                of implementation of the NWPR (i.e., between June 22, 2020, to June 21,
                2021), 100% were found to be non-jurisdictional ephemeral
                resources.\40\ In Arizona, of the 1,525 streams assessed in AJDs in the
                first year of implementation of the NWPR, 1,518, or 99.5%, were found
                to be non-jurisdictional ephemeral resources. While the Corps found
                high percentages of streams in Arizona to be non-jurisdictional between
                2016 and 2020, the NWPR resulted in a ten-fold increase in the total
                number of individual resources documented as non-jurisdictional in
                AJDs.
                ---------------------------------------------------------------------------
                 \40\ These non-jurisdictional ephemeral resources are
                predominantly ephemeral streams, but a small portion may be swales,
                gullies, or pools.
                ---------------------------------------------------------------------------
                 For example, the average annual number of individual stream
                resources considered in AJDs in Arizona between 2016-2020 was 147 (of
                which 138 were determined non-jurisdictional), compared to 1,525 stream
                reaches assessed under the NWPR (of which 1,521 were determined non-
                jurisdictional accounting for all exclusions). The number of stream
                reaches assessed in Arizona also dominated the number of evaluations
                completed nationally under the NWPR, which is incongruent with the
                geographic extent of water resources in this country. The number of
                stream reaches assessed in Arizona constituted 9% of the total stream
                reaches assessed nationally and 13% of the ephemeral reaches assessed
                nationally over the first twelve months in which the NWPR was
                implemented.\41\ This increase in the number of streams assessed and
                found to be non-jurisdictional in Arizona under the NWPR highlights the
                disproportionate impacts this rule had on water resource protection in
                this state and in similar arid regions of this country.
                ---------------------------------------------------------------------------
                 \41\ There were a total of 16,787 stream reaches assessed via
                AJDs nationwide between June 22, 2020 and June 21, 2021.
                ---------------------------------------------------------------------------
                 The number of individual stream reaches considered under PJDs also
                declined precipitously in these states under the NWPR, while many more
                streams were evaluated and determined to be non-jurisdictional through
                AJDs. As mentioned previously, project proponents who request an AJD
                obtain an official Corps document stating the presence or absence of
                ``waters of the United States'' on a parcel or a written statement and
                map identifying the limits of ``waters of the United States'' on a
                parcel. In contrast, an applicant can elect to use a PJD to voluntarily
                waive or set aside questions regarding Clean Water Act jurisdiction
                over a particular site and thus move forward assuming all waters will
                be treated as jurisdictional without making a formal determination.
                There are time savings and sometimes cost savings associated with
                requesting a PJD in lieu of an AJD. However, proportionally fewer PJDs
                being requested under the NWPR indicate that fewer project proponents
                are requesting that aquatic resources on their project site be treated
                as if they are jurisdictional.
                 In Arizona, the annual average number of individual stream reaches
                considered under PJDs and similar alternatives to AJDs between 2016 to
                2020 was 941, while under the NWPR in 2020-2021 it was only 45.\42\
                When looking at the total number of individual streams reaches over
                time, under the NWPR Arizona experienced an approximate 95% decrease in
                individual stream reaches being considered via PJDs and a 9-fold
                increase in individual stream reaches being considered via AJDs,
                compared to pre-2015 regulatory practice. Similar metrics for New
                Mexico show an 84% decrease in individual streams being considered via
                PJDs and a 28-fold increase in individual streams being considered via
                AJDs under the NWPR. Based on averages for non-jurisdictional streams
                from 2016-2020 compared to non-jurisdictional streams under the NWPR,
                there has been a 10-fold increase in non-jurisdictional findings for
                streams in Arizona and a 36-fold increase in non-jurisdictional
                findings for streams in New Mexico following implementation of the
                NWPR. Compounding resource losses, eliminating these streams from
                jurisdiction under the NWPR also typically eliminated jurisdiction over
                wetlands which otherwise might meet adjacency criteria.
                ---------------------------------------------------------------------------
                 \42\ The AJD values associated with the NWPR fall outside of the
                95% confidence interval calculated for annual data from 2016-2020.
                Note that in New Mexico and Arizona, the 2015 Clean Water Rule was
                never implemented due to litigation stays. The PJD values associated
                with the NWPR do not fall outside of the 95% confidence interval
                calculated for annual data from 2016-2020; this is likely a product
                of scale. See the Technical Support Document section III.B.ii for
                more analysis.
                ---------------------------------------------------------------------------
                 The NWPR also significantly reduced the number of Clean Water Act
                section 404 permits required for dredging and filling activity
                nationwide. The Corps has identified at least 368 projects from June
                22, 2020 to June 21, 2021 through its ORM2 database that would have
                needed a Clean Water Act section 404 permit pre-NWPR, but no longer did
                under the NWPR's definition of ``waters of the United States.'' \43\
                Moreover, in comparing 2020-2021 to similar annual data from 2016 to
                2020 from
                [[Page 69415]]
                implementation of the 1986 regulations consistent with Supreme Court
                case law, there was on average an increase of over 100% in the number
                of projects determined to not require section 404 permits under the
                Clean Water Act due to activities not occurring in ``waters of the
                United States'' or activities occurring in waters that were deemed no
                longer ``waters of the United States'' due to the NWPR. The number of
                projects that did not require a section 404 permit under the NWPR was
                likely much greater than these numbers indicate because project
                proponents did not need to notify the Corps if they had already
                received an AJD that concluded waters in the review area were not
                ``waters of the United States,'' and because many project proponents
                may not have sought a jurisdictional determination or applied for a
                permit at all if they believed their aquatic resources were non-
                jurisdictional under the NWPR. Many projects could have occurred
                without consultation with the Corps due to the NWPR's narrow definition
                of ``waters of the United States'' and expansive non-jurisdictional
                categories. Therefore, while the Corps' ORM2 data shed light on the
                trend and magnitude of impacts to the scope of jurisdiction under the
                NWPR, it is fair to assume that these impacts are a significant
                underestimate.\44\
                ---------------------------------------------------------------------------
                 \43\ This tracking method only applies when 100% of jurisdiction
                is lost under NWPR (i.e., if even 1 aquatic resource out of 100 that
                is proposed to be impacted remains jurisdictional, this method is
                not used). Additionally, this tracking method has not been
                implemented uniformly across the United States, and is likely under-
                representative even for those cases in which 100% of jurisdiction
                was lost under the NWPR.
                 \44\ Requests for AJDs and the jurisdictional dispositions of
                the aquatic resources evaluated as part of those AJDs are imperfect
                measures of activities that might affect those jurisdictional or
                non-jurisdictional aquatic resources. The AJD data in the Corps ORM2
                database generally contain only records for situations in which
                landowners or project proponents have requested jurisdictional
                determinations from the Corps or that are associated with an
                enforcement action, and thus do not represent all aquatic resources
                that exist within the United States. The proportion and specific
                types of aquatic resources evaluated for jurisdiction via AJDs
                varies both geographically and also from year to year. In addition,
                the ORM2 data collected from AJDs conducted under different
                regulatory regimes have some metrics that are not directly
                comparable. Notwithstanding these limitations, the volume of ORM2
                data on AJDs and associated aquatic resources is quite large and is
                tracked in a reasonably accurate fashion, and thus provides a
                reasonable estimate of overall trends and conditions on the ground.
                It represents the best data available to the agencies at this time.
                ---------------------------------------------------------------------------
                ii. States and Tribes Did Not Fill the Regulatory Gap Left by the NWPR
                 Some stakeholders have argued that the diminished scope of ``waters
                of the United States'' would not necessarily reduce protections for
                waters as a practical matter, because states, tribes, and local
                entities may regulate discharges even in the absence of Clean Water Act
                regulation. See section V.A.3.b of this preamble. This perspective is
                consistent with the NWPR's emphasis that, in the face of a narrower
                scope of ``waters of the United States,'' ``the controls that States,
                Tribes, and local entities choose to exercise over their land and water
                resources . . .'' would help to achieve the objective of the Act. 85 FR
                22259, April 21, 2020. Yet while some states and tribes regulate
                ``waters of the state'' or ``waters of the tribe'' more broadly than
                the federal government under their own laws, many newly non-
                jurisdictional waters under the NWPR were in states and on tribal lands
                that do not regulate waters beyond those covered by the Clean Water
                Act. Under the NWPR, discharges into these waters could have occurred
                without any restriction.
                 As discussed in the Economic Analysis for the Proposed Rule, many
                states and tribes do not regulate waters more broadly than the Clean
                Water Act requires. Economic Analysis, Chapter II; NWPR Economic
                Analysis at 30-31. Contrary to the predictions made in the NWPR
                Economic Analysis, during the year in which the NWPR was in effect, the
                net change made by states was deregulatory in nature. Two states which
                had previously protected state waters beyond the scope of ``waters of
                the United States'' removed these expansive protections, whereas no
                states that had previously lacked these broader protections established
                them. See NWPR Economic Analysis at 39-41 (estimating that certain
                states are likely to continue their current permitting practices for
                dredged and fill material) and the Economic Analysis for the Proposed
                Rule Chapter II (indicating that two of those states sought to reduce
                the scope of state clean water protections after the NWPR was
                finalized, and none of them sought to expand protections.).
                 The agencies understand that revising state regulations and/or laws
                takes time and the agencies do not know how some states might have
                responded if the NWPR had been in place for more than a year, but the
                agencies have no basis to expect that more states that currently lack
                protections beyond the NWPR federal floor would have established them.
                Indeed, the External Environmental Economics Advisory Committee (E-
                EEAC) has stated that the model that the NWPR used to forecast state
                responses to that rule was overly optimistic with respect to the
                likelihood that states would address a federal regulatory gap, in part
                based on the agencies' failure to fully consider states' responses to
                past changes to the definition of ``waters of the United States''
                (i.e., only two states directly changed regulations in response to the
                decision in SWANCC that the use of ``isolated'' non-navigable
                intrastate ponds by migratory birds was not by itself a sufficient
                basis for the exercise of federal authority under the Clean Water Act,
                and the agencies' significant resulting change in implementation of the
                Act). See E-EEAC Report on the Repeal of the Clean Water Rule and its
                Replacement with the Navigable Waters Protection Rule to Define Waters
                of the United States (WOTUS) 5-6, available at https://www.e-eeac.org/wotusreport.
                 The agencies are also not aware of any tribes that expanded their
                clean water protections to compensate for a reduction in protections
                under the NWPR. During the agencies' tribal consultation and
                coordination for this rulemaking process, tribes overwhelmingly
                indicated that they lack the independent resources and expertise to
                protect their waters and therefore rely on Clean Water Act protections.
                See section IV.C of this preamble and the Summary of Tribal
                Consultation and Coordination, available in the docket for this
                proposed rule. This feedback is consistent with the concerns expressed
                during the NWPR rulemaking process. See, e.g., 85 FR 22336-22337, April
                21, 2020 (``many Tribes may lack the capacity to create a tribal water
                program under tribal law, to administer a program, or to expand
                programs that currently exist. Other tribes may rely on the Federal
                government for enforcement of water quality violations'').
                 Given the limited authority of many states and tribes to regulate
                waters more broadly than the Federal government, the narrowing of
                federal jurisdiction would mean that discharges into the newly non-
                jurisdictional waters would in many cases no longer be subject to
                regulation, including permitting processes and mitigation requirements
                designed to protect the chemical, physical, and biological integrity of
                the nation's waters. The agencies have heard concerns from a broad
                array of stakeholders, including states, tribes, scientists, and non-
                governmental organizations, that corroborated the agencies' data and
                indicated that the NWPR's reduction in the jurisdictional scope of the
                Clean Water Act would cause significant environmental harms. Ephemeral
                streams and their associated wetlands, wetlands that do not meet the
                NWPR's revised adjacency criteria, and other aquatic resources not
                protected by the NWPR provide numerous ecosystem services. The absence
                of protections for such resources and any subsequent unregulated and
                unmitigated impacts to such resources would have caused cascading,
                cumulative, and substantial downstream harm, including damage
                [[Page 69416]]
                connected to water supplies, water quality, flooding, drought, erosion,
                and habitat integrity, thereby undermining the objective of the Clean
                Water Act (see section V.A.2 of this preamble). See Pascua Yaqui v.
                EPA, no. 4:20-cv-00266, slip op. at 9-10 (citing evidence that the
                agencies and plaintiffs provided of a ``substantial reduction in waters
                covered under the NWPR'' as demonstrating ``the possibility of serious
                environmental harm'' that weighed in favor of vacating the rule.); see
                also Navajo Nation v. Regan, no. 2:20-cv-00602, slip op. at 6-7 (citing
                the same reduction particularly ```an increase in determinations by the
                Corps that waters are non-jurisdictional,' including excluded ephemeral
                resources, `and an increase in projects for which CWA Section 404
                permits are no longer required,''' as weighing in favor of vacatur).
                 In conclusion, the agencies do not believe the NWPR is a suitable
                alternative to the proposed rule because it failed to advance the
                objective of the Act, including through its elimination of the
                significant nexus standard and the absence of any alternative standard
                that would protect the chemical, physical, and biological integrity of
                the nation's waters; it is inconsistent with scientific information
                about protecting water quality; its implementation proved confusing,
                difficult, and often infeasible; and it drastically reduced the numbers
                of waters protected by the Clean Water Act, including waters that
                affect the integrity of downstream traditional navigable waters,
                interstate waters, and the territorial seas.
                C. Proposed Rule
                 The agencies are proposing to restore the longstanding, familiar
                1986 regulations, with amendments to reflect the agencies'
                determination of the statutory limits on the scope of the ``waters of
                the United States'' informed by Supreme Court case law. Therefore, this
                proposed rule retains the structure of the agencies' 1986 definition of
                ``waters of the United States,'' and the text of that definition where
                revisions are not warranted. Continuity with the 1986 regulations will
                minimize confusion and provide regulatory stability for the public, the
                regulated community, and the agencies, while protecting the nation's
                waters. Each aspect of the proposed rule will be discussed in more
                detail below.
                 The implementation section V.D of this preamble identifies features
                that the agencies have, as a matter of practice, generally not asserted
                jurisdiction over and the agencies propose to continue implementing the
                regulations consistent with that longstanding interpretation and
                practice. In addition, the agencies note that Congress has exempted or
                excluded certain discharges from the Clean Water Act or from specific
                permitting requirements. The proposed rule also would not affect any of
                the exemptions, including exemptions from section 404 permitting
                requirements provided by section 404(f), such as those for normal
                farming, ranching, and silviculture activities. 33 U.S.C. 1344(f); 40
                CFR 232.3; 33 CFR 323.4. The proposed rule would not affect the
                existing statutory or regulatory exemptions or exclusions from section
                402 NPDES permitting requirements, such as for agricultural stormwater
                discharges and return flows from irrigated agriculture, or the status
                of water transfers. 33 U.S.C. 1342(l)(1), (l)(2); 33 U.S.C. 1362(14);
                40 CFR 122.3(f), 122.2. In addition, where waters are covered by the
                Clean Water Act, the agencies have adopted measures to simplify
                compliance with the Act such as general permits and tools for
                expediting the permitting process (e.g., mitigation banks, in-lieu fee
                programs, and functional/conditional assessment tools). The agencies
                intend to continue to develop general permits and simplified procedures
                to ensure that projects, particularly those that offer environmental or
                public benefits, can proceed with the necessary environmental
                safeguards while minimizing permitting delays.
                 The agencies have highlighted areas throughout the proposal where
                they are seeking comment on specific aspects of the revised definition
                of ``waters of the United States'' and implementation of that
                definition. The agencies are also generally seeking comment from the
                public on all aspects of this proposal to support development of the
                final rule.
                1. Traditional Navigable Waters
                 The proposed rule retains the provision in the 1986 regulations
                that defines ``waters of the United States'' to include ``all waters
                that are currently used, or were used in the past, or may be
                susceptible to use in interstate or foreign commerce, including all
                waters which are subject to the ebb and flow of the tide.'' 33 CFR
                328.3(a)(1) (2014); 40 CFR 122.2 (2014); 40 CFR 230.3(s)(1) (2014).
                Such waters are often referred to as ``traditional navigable waters.''
                With respect to traditional navigable waters, the text of the 1986
                regulations and the text of the NWPR are identical. The agencies are
                not proposing to amend this longstanding text defining ``traditional
                navigable waters.''
                 The NWPR maintained the categories of traditional navigable waters
                and the territorial seas in the definition of ``waters of the United
                States,'' but consolidated these two categories into a single paragraph
                in the regulatory text in order to streamline the text. 85 FR 22280,
                April 21, 2020. Because the 1986 regulations kept the traditional
                navigable waters provisions and the territorial seas provisions
                separate, this proposed rule does as well. The agencies are seeking
                comment, however, on whether it would be useful to similarly streamline
                the proposed rule by consolidating the traditional navigable waters,
                interstate waters, and the territorial seas provisions into one
                provision since under the 1986 regulations and the proposed rule the
                jurisdictional status of the other categories of waters relies on their
                connection to a traditional navigable water, interstate water, or the
                territorial seas (and, where required, meeting either the relatively
                permanent or the significant nexus standard). The agencies also seek
                comment on whether consolidation would cause confusion regarding the
                consistency of the proposed rule with the 1986 regulations, because
                such a change would require corresponding changes to cross references
                and the numbering of other provisions.
                 Supreme Court decisions have not questioned the inclusion of
                traditional navigable waters in the definition of ``waters of the
                United States.'' E.g., SWANCC, 531 U.S. 159, 172 (``[t]he 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.'').
                 The agencies also are making no changes to their longstanding
                guidance on traditional navigable waters for purposes of Clean Water
                Act jurisdiction. Waters will continue to be considered traditional
                navigable waters, and thus jurisdictional under this provision of the
                proposed rule, if they:
                 Are subject to section 9 or 10 of the Rivers and Harbors
                Act of 1899;
                 have been determined by a federal court to be navigable-
                in-fact under federal law;
                 are waters currently being used for commercial navigation,
                including commercial waterborne recreation (for example, boat rentals,
                guided fishing trips, or water ski tournaments);
                 have historically been used for commercial navigation,
                including commercial waterborne recreation; or
                [[Page 69417]]
                 are susceptible to being used in the future for commercial
                navigation, including commercial waterborne recreation.
                 See ``U.S. Army Corps of Engineers Jurisdictional Determination
                Form Instructional Guidebook, Appendix D, `Traditional Navigable
                Waters''' (hereinafter, ``Appendix D''). The NWPR also continued use of
                Appendix D, stating ``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.'' 85 FR 22281, April 21, 2020.\45\ However, after the
                NWPR was promulgated the agencies issued a coordination memo that
                created some confusion. ``U.S. Environmental Protection Agency (EPA)
                and U.S. Army Corps of Engineers (Corps) Process for Elevating and
                Coordinating Specific Draft Determinations under the Clean Water Act
                (CWA)'' (hereinafter ``TNW Coordination Memo''). The memorandum
                established an implementation process by which the agencies elevate to
                their headquarters for coordination certain case-specific and stand-
                alone Clean Water Act traditional navigable water determinations
                concluding a water is ``susceptible to use'' solely based on evidence
                of recreation-based commerce. Id. On November 17, 2021, the TNW
                Coordination Memo was rescinded. Regardless of any confusion caused by
                the TNW Coordination Memo, the Supreme Court has been clear that
                ``[e]vidence of recreational use, depending on its nature, may bear
                upon susceptibility of commercial use.'' PPL Montana v. Montana, 565
                U.S. 576, 600-01 (2012) (in the context of navigability at the time of
                statehood and quoting Appalachian Elec. Power Co., 311 U.S. at 416
                (``[P]ersonal or private use by boats demonstrates the availability of
                the stream for the simpler types of commercial navigation''); Utah, 283
                U.S. at 82 (fact that actual use has ``been more of a private nature
                than of a public, commercial sort . . . cannot be regarded as
                controlling'')).
                ---------------------------------------------------------------------------
                 \45\ Appendix D is an attachment to the U.S. Army Corps of
                Engineers Jurisdictional Determination Form Instructional Guidebook
                that was published in 2007 concurrently with the 2007 Rapanos
                Guidance, available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2316. The Rapanos Guidance was
                updated 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.''
                Appendix D operates in tandem with the Rapanos Guidance, along with
                other agency resources, to assist in guiding field implementation of
                Clean Water Act jurisdictional determinations.
                ---------------------------------------------------------------------------
                2. Interstate Waters
                 The proposed rule would restore the longstanding categorical
                protections for interstate waters, regardless of their navigability,
                that were established by the earliest predecessors to the 1972 Clean
                Water Act and remained in place until the promulgation of the NWPR.
                Interstate waters are waters of the several states and therefore
                unambiguously ``waters of the United States.'' Categorical protection
                of interstate waters is the interpretation of the Clean Water Act that
                is most consistent with the text of the statute, including section
                303(a), its purpose and history, Supreme Court case law, and the
                agencies' charge to implement a ``comprehensive regulatory program''
                that protects the chemical, physical, and biological integrity of the
                nation's waters.
                 Until 1972, the predecessors of the Clean Water Act explicitly
                protected interstate waters independent of their navigability. The 1948
                Water Pollution Control Act declared that the ``pollution of interstate
                waters'' and their tributaries is ``a public nuisance and subject to
                abatement.'' 33 U.S.C. 466a(d)(1) (1952) (codifying Pub. L. 80-845
                section 2(d)(1), 62 Stat. 1156 (1948)). Interstate waters were defined
                without reference to navigability: ``all rivers, lakes, and other
                waters that flow across, or form a part of, State boundaries.'' 33
                U.S.C. 466i(e) (1952) (codifying Pub. L. 80-845 section 10(e), 62 Stat.
                1161 (1948)).
                 In 1961, Congress broadened the 1948 statute and made the pollution
                of ``interstate or navigable waters'' subject to abatement, retaining
                the definition of ``interstate waters.'' 33 U.S.C. 466g(a) (1964)
                (codifying Pub. L. 87-88 section 8(a), 75 Stat. 204, 208 (1961)). In
                1965, Congress required states to develop water quality standards for
                ``interstate waters or portions thereof within such State.'' 33 U.S.C.
                1160(c)(1) (1970) (codifying Pub. L. 89-234 section 5, 79 Stat. 903,
                907 (1965)); see also 33 U.S.C. 1173(e) (1970) (retaining definition of
                ``interstate waters''). In the 1972 Act, Congress abandoned the
                ``abatement'' approach initiated in the 1948 statute in favor of a
                focus on permitting for discharges of pollutants.
                 The NWPR asserted that Congress' replacement of the term
                ``navigable or interstate waters'' with ``navigable waters'' in 1972
                was an ``express rejection'' of the regulation of interstate waters as
                an independent category, reflecting Congress' intent to protect
                interstate waters only to the extent that they are navigable. 85 FR
                22583, April 21, 2020. In support of its rationale, the NWPR cited the
                order of the U.S. District Court for the Southern District of Georgia
                remanding the 2015 Clean Water Rule. Id.; citing Georgia v. Wheeler,
                418 F. Supp. 3d 1336 (S.D. Ga. 2019). That order found that the
                categorical inclusion of interstate waters exceeds the agencies'
                authority under the Clean Water Act because it ``reads the term
                navigability out of the CWA,'' and would assert jurisdiction over
                waters that are not navigable-in-fact and otherwise have no significant
                nexus to any other navigable-in-fact water. Id. at 1358-59. The court
                also found the standard overly broad because it would result in Clean
                Water Act jurisdiction over tributaries, adjacent waters, and case-by-
                case waters based on their relationship to non-navigable interstate
                waters. Id. at 1359-60.
                 The agencies view the interpretation of the agencies' authority
                over interstate waters articulated in the NWPR and in Georgia v.
                Wheeler as inconsistent with both the text and the history of the Clean
                Water Act, as well as Supreme Court case law. While the term
                ``navigable waters'' is ambiguous in some respects, interstate waters
                are waters that are clearly covered by the plain language of the
                definition of ``navigable waters.'' Congress defined ``navigable
                waters'' to mean ``the waters of the United States, including the
                territorial seas.'' The Supreme Court has recognized that ``the power
                conferred by the Commerce Clause [is] broad enough to permit
                congressional regulation of activities causing air or water pollution,
                or other environmental hazards that may have effects in more than one
                State.'' Hodel v. Virginia Surface Mining & Reclamation Ass'n, 452 U.S.
                264, 282 (1981). Interstate waters are, by their very nature, waters of
                the ``several States,'' U.S. Const. section 8, and, consequently,
                waters ``of the United States.'' The Clean Water Act reflects Congress'
                recognition that the degradation of water resources in one state may
                cause significant harms in states other than that in which the
                pollution occurs.
                 In addition, the text of the 1972 Act specifically addresses
                ``interstate waters'' regardless of their connection to navigability.
                The 1972 statute retains the term ``interstate waters'' in 33 U.S.C.
                1313(a), a provision added in 1972, which provides that pre-existing
                water quality standards for ``interstate waters'' remain in effect
                unless EPA determined that they were inconsistent with any applicable
                requirements of the pre-1972 version of the Act. That plain language is
                a clear indication that Congress
                [[Page 69418]]
                intended the agencies to continue to protect the water quality of
                interstate waters without reference to their navigability. Excluding
                ``interstate waters'' as an independent category of Clean Water Act
                jurisdiction disregards the plain language of section 303(a).
                 The Supreme Court has concluded that the 1972 amendments ``were not
                merely another law `touching interstate waters,' '' but rather
                ``occupied the field through the establishment of a comprehensive
                regulatory program supervised by an expert administrative agency.''
                City of Milwaukee v. Illinois, 451 U.S. 304, 317 (1981). Thus, the 1972
                amendments superseded the federal common law of nuisance as a means to
                protect interstate waters in favor of a statutory ``all-encompassing
                program of water pollution regulation,'' id. at 318, and they did not
                curtail the scope of protected waters.
                 Even if the text and history of the statute and Supreme Court case
                law interpreting the Act do not unambiguously resolve the issue, the
                situation addressed by the Supreme Court in the City of Milwaukee cases
                highlights the reasonableness of the agency's interpretation that the
                Clean Water Act protects interstate waters. The City of Milwaukee
                litigation involved alleged discharges of inadequately treated sewage
                from Milwaukee, Wisconsin sewer systems directly into Lake Michigan,
                which also borders Illinois. As the Supreme Court noted, prior to
                passage of the Clean Water Act, these discharges would have had to be
                resolved through litigation, in which the courts must apply ``often
                vague and indeterminate nuisance concepts and maxims of equity
                jurisprudence.'' Id. at 317. The Clean Water Act, however, replaced
                this unpredictable and inefficient approach with ``a comprehensive
                regulatory program supervised by an expert administrative agency.'' Id.
                The Court in Arkansas v. Oklahoma also stated in the context of an
                NPDES permit for a discharge of pollutants to interstate waters that
                while the Clean Water Act may place some limits on downstream states'
                participation in the permitting process, those limits ``do not in any
                way constrain the EPA's authority to require a point source to comply
                with downstream water quality standards.'' 503 U.S. at 106.
                 The potential for interstate harm, and the consequent need for
                federal regulation, is particularly clear with respect to water bodies
                that span more than one state. The alternative interpretation would
                leave interstate waters that do not fall within any other provisions in
                the definition of ``waters of the United States'' without federal
                protection and parties in different states to resolve concerns about
                upstream discharges in non-jurisdictional waters through litigation
                using ``often vague and indeterminate nuisance concepts and maxims of
                equity jurisprudence.'' City of Milwaukee, 451 U.S. at 317; 85 FR
                22286, April 21, 2020. Restoration of longstanding protections for
                interstate waters, regardless of whether they are navigable-in-fact,
                would enable the agencies to efficiently and effectively address
                interstate water quality issues. The agencies interpret interstate
                waters to encompass all waters that Congress has sought to protect
                since 1948: all rivers, lakes, and other waters that flow across, or
                form a part of, state boundaries. Pub. L. 80-845, sec. 10, 62 Stat.
                1155, at 1161 (1948). These waters need not meet the relatively
                permanent standard or significant nexus standard. See Technical Support
                Document section I.B. for further discussion of interstate waters.
                 Interstate waters may be streams, lakes or ponds, or wetlands.
                Under this provision of the proposed rule, consistent with the pre-2015
                regulatory regime, the agencies would consider lakes, ponds, and
                similar lentic (or still) water features, as well as wetlands, crossing
                state boundaries jurisdictional as interstate waters in their entirety.
                For streams and rivers, including impoundments, the agencies would
                determine the upstream and downstream extent of the stream or river
                crossing a state boundary or serving as a state boundary that should be
                considered the ``interstate water.'' One method of determining the
                extent of a riverine ``interstate water'' is the use of stream order.
                Stream order is a common, longstanding scientific concept of assigning
                whole numbers to indicate the branches of a stream network. Under this
                method, for rivers and streams the ``interstate water'' would extend
                upstream and downstream of the state boundary for the entire length
                that the water is of the same stream order. For interstate waters that
                are lakes and ponds or wetlands, the entire lake, pond, or wetland
                could be considered the interstate water through the entirety of its
                delineated extent. The agencies are requesting comment on this approach
                or others for implementing the interstate waters provision of the
                proposed rule. For instance, if a water serves as the state boundary,
                the entire length of the river that serves as the boundary could be
                considered the appropriate extent of the interstate water.
                 The agencies are seeking comment on whether interstate waters
                should encompass waters that flow across, or form a part of, boundaries
                of federally recognized tribes because these waters flow across, or
                form a part of, state boundaries. See Public Law 80-845, sec. 10, 62
                Stat. 1155, at 1161 (1948). In comments submitted to the agencies as
                part of the tribal consultation and coordination process for this
                proposed rule, several tribes and tribal organizations stated that
                interstate waters should include waters that border upon or traverse
                tribal lands, both between and from state to tribe (or vice versa) and
                between and from one tribe to another (in instances where tribal lands
                are adjacent to each other). The agencies are also interested in
                comments on whether and how to identify what constitutes a tribal
                boundary for purposes of interstate waters under the Clean Water Act,
                for example, boundaries associated with the term ``Indian country'' as
                defined at 18 U.S.C. 1151 or reservation boundaries.
                3. Other Waters
                 The agencies are proposing to retain the ``other waters'' category
                from the 1986 regulations in the definition of ``waters of the United
                States,'' but with changes informed by relevant Supreme Court
                precedent. Under the 1986 regulations, ``other waters'' (such as
                intrastate rivers, lakes, and wetlands that are not otherwise
                jurisdictional under other sections of the rule) could be determined to
                be jurisdictional if the use, degradation, or destruction of the water
                could affect interstate or foreign commerce. The proposed rule amends
                the 1986 regulations to delete all of the provisions referring to
                authority over activities that ``could affect interstate or foreign
                commerce'' and replace them with the relatively permanent and
                significant nexus standards the agencies have developed based on their
                best judgment and relevant Supreme Court case law. The proposed rule
                provides that ``other waters'' meet the relatively permanent standard
                if they are relatively permanent, standing or continuously flowing
                bodies of water with a continuous surface connection to a traditional
                navigable water, interstate water, or the territorial seas. The
                proposed rule also provides that ``other waters'' meet the significant
                nexus standard if they, either alone or in combination with similarly
                situated waters in the region, significantly affect the chemical,
                physical, or biological integrity of a traditional navigable water,
                interstate water, or the territorial seas. Thus, the proposed rule
                would provide for case-specific analysis of waters not addressed by any
                other provision of the definition to determine whether they are
                ``waters of the United
                [[Page 69419]]
                States'' under the relatively permanent or significant nexus standards.
                In light of agency guidance discussed below, the agencies have not in
                practice asserted jurisdiction over ``other waters'' based on the 1986
                regulations' provision since SWANCC. Section V.D of this preamble
                solicits comment on this practice and other implementation approaches
                for this provision of the proposed rule.
                 The text of the 1986 regulations reflected the agencies'
                interpretation at the time, based primarily on the legislative history
                of the Act, that the jurisdiction of the Clean Water Act extended to
                the maximum extent permissible under the Commerce Clause of the
                Constitution. SWANCC did not invalidate the 1986 regulations' ``other
                waters'' provision or any other parts of the 1986 regulations'
                definition of ``waters of the United States.'' Based on that case and
                subsequent Supreme Court decisions, the agencies conclude that
                asserting jurisdiction over non-navigable, intrastate ``other waters''
                based solely on whether the use, degradation, or destruction of the
                water could affect interstate or foreign commerce pushes the scope of
                the Clean Water Act beyond the limitations intended by Congress. The
                proposal is consistent with many of the concerns the agencies
                identified in guidance issued in 2003 (discussed further below). In
                addition, the proposed rule reflects consideration of the principles
                the NWPR identified as foundational to the Court's opinion in SWANCC.
                See 85 FR 22265, April 21, 2020 (``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.'').
                 The proposed rule would replace the interstate commerce test with
                the relatively permanent and significant nexus standards because, as
                discussed in section V.A of this preamble, those standards are
                consistent with the text of the Clean Water Act, advance the objective
                of the Act, and are consistent with relevant decisions of the Supreme
                Court. Waters that do not fall within one of the more specific
                categories identified in the proposed rule may still meet either the
                relatively permanent or significant nexus standard. For example, a lake
                that is not a tributary and is not a wetland may have a continuous
                surface connection to a traditional navigable water, and the ``other
                waters'' provision as proposed would allow for such a water to be
                evaluated for jurisdiction. This is consistent with Supreme Court
                precedent. As the Rapanos plurality concluded, ``relatively permanent,
                standing or continuously flowing bodies of water,'' 547 U.S. at 739,
                that are connected to traditional navigable waters, id. at 742, and
                waters with a ``continuous surface connection'' to such water bodies,
                id. (Scalia, J., plurality opinion), are ``waters of the United
                States'' under the relatively permanent standard. And as Justice
                Kennedy concluded, SWANCC held that ``to constitute `navigable waters'
                under the Act, a water or wetland must possess a `significant nexus' to
                waters that are or were navigable in fact or that could reasonably be
                so made.'' Id. at 759 (citing SWANCC, 531 U.S. at 167, 172).
                 The agencies note that in 2003, they issued a Joint Memorandum
                regarding SWANCC. See 68 FR 1991, 1995 (January 15, 2003) (``SWANCC
                Guidance''). In the guidance, the agencies stated that in view of
                SWANCC, neither agency would assert Clean Water Act jurisdiction over
                isolated waters that are both intrastate and non-navigable, where the
                sole basis available for asserting Clean Water Act jurisdiction rests
                on the factors listed in the ``Migratory Bird Rule.'' In the preamble
                to the 1986 regulations, the agencies had stated that ``waters of the
                United States'' include waters ``[w]hich are or would be used as
                habitat by birds protected by Migratory Bird Treaties,'' as well as
                waters ``[w]hich are or would be used as habitat by other migratory
                birds which cross state lines.'' 51 FR 41216-17 (November 13, 1986).
                That preamble language became known as the ``Migratory Bird Rule.'' In
                addition to ending use of the ``Migratory Bird Rule,'' the SWANCC
                Guidance also stated that, cognizant of the Supreme Court's direction
                in SWANCC, with respect to all waters subject to the ``other waters''
                provision, ``field staff should seek formal project-specific
                Headquarters approval prior to asserting jurisdiction over such waters,
                including permitting and enforcement actions.'' 68 FR 1996 (January 15,
                2003). The Rapanos Guidance ``[did] not address SWANCC nor does it
                affect the Joint Memorandum regarding that decision issued by the
                General Counsels of EPA and the Department of the Army on January 10,
                2003.'' Rapanos Guidance at 4 n.19. As a result of the SWANCC
                Guidance's directive to field staff, field staff have not in practice
                sought Headquarters approval and the agencies have not asserted
                jurisdiction over waters based on the ``other waters'' provision of the
                1986 regulations since then.
                 The ``other waters'' provision in the 1986 regulations contains a
                non-exclusive list of water types that could be jurisdictional under
                this provision if they are not jurisdictional under the other
                provisions of the definition: ``[a]ll other waters such as intrastate
                lakes, rivers, streams (including intermittent streams), mudflats,
                sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa
                lakes, or natural ponds.'' The agencies are not proposing to change
                this language. Rather, the agencies are proposing to replace the
                Commerce Clause-based standard for determining jurisdiction with the
                relatively permanent and significant nexus standards. It is important
                to note that the list of water types does not reflect a conclusion that
                these waters are necessarily jurisdictional; rather the list is simply
                meant to inform the public of types of waters that can be
                jurisdictional if they meet the requisite test (under the proposal,
                either the relatively permanent standard or the significant nexus
                standards), even though they do not fall within the other provisions of
                the proposed rule. The list led to confusion in the past when it was
                sometimes incorrectly read as an exclusive list. There has also been
                confusion about some of the listed water types; for example, the list
                includes intermittent streams and was meant to allow for jurisdictional
                evaluation of intermittent streams that do not fall within the other
                categories (such as intermittent streams that are not tributaries to a
                traditional navigable water, interstate water, or territorial sea but
                which under the 1986 regulations could affect interstate commerce and
                under the proposed rule could meet the significant nexus standard) and
                not to imply that intermittent streams were not jurisdictional under
                the tributary provision of the 1986 regulations.
                 The agencies are seeking comment on whether it would be helpful to
                the public to delete the list of water types or to otherwise provide
                more clarity to the list of water types in the regulation. For
                instance, the agencies could delete the list of water types in the
                ``other waters'' provision of the 1986 regulations and simply state in
                the rule that the ``other waters'' category includes ``all other
                intrastate waters (including wetlands)'' that meet either the
                relatively permanent standard or the significant nexus standard.
                However, removing the list of water types would not be meant to imply
                that any of the water types listed in the 1986 regulations are not
                subject to jurisdiction under this provision of the proposed rule if
                they meet either the relatively permanent standard or the significant
                nexus standard. The agencies
                [[Page 69420]]
                also solicit comment on whether the final rule should add or delete
                particular water types from the list.
                 In the NWPR, the category of waters most analogous to the ``other
                waters'' category was the category for lakes, ponds, and impoundments
                of jurisdictional waters that met certain tests. Because those
                limitations on the scope of jurisdiction were not related to the
                effects of other waters on the water quality of foundational waters,
                the agencies are proposing an approach based in the relatively
                permanent and significant nexus standards.
                4. Impoundments
                 The proposed rule retains the provision in the 1986 regulations
                that defines ``waters of the United States'' to include impoundments of
                ``waters of the United States'' with one change. Waters that are
                determined to be jurisdictional under the ``other waters'' provision
                would be excluded from this provision under the proposed rule.
                 The Supreme Court has confirmed that damming or impounding a
                ``water of the United States'' does not make the water non-
                jurisdictional. See S.D. Warren Co. v. Maine Bd. of Envtl. Prot., 547
                U.S. 370, 379 n.5 (2006) (``[N]or can we agree that one can
                denationalize national waters by exerting private control over
                them.''). While the definition of ``waters of the United States'' was
                not before the Court in S.D. Warren, the Court's conclusion supports
                the agencies' longstanding interpretation of the Clean Water Act that a
                ``water of the United States'' remains a ``water of the United States''
                even if it is impounded, as reflected in the 1986 regulations and
                continued in this proposal. The Ninth Circuit has similarly found that
                ``it is doubtful that a mere man-made diversion would have turned what
                was part of the waters of the United States into something else and,
                thus, eliminated it from national concern.'' United States v. Moses,
                496 F.3d 984, 988 (9th Cir. 2007), cert. denied, 554 U.S. 918 (2008).
                 The agencies are proposing to exclude impoundments of waters that
                are determined to be jurisdictional under the ``other waters''
                provision. This proposal is practical: as discussed in sections V.C.5
                and 7 below, the agencies are proposing that the ``tributaries''
                category not include tributaries of ``other waters'' and the adjacent
                wetlands category not include wetlands adjacent to ``other waters.''
                This change reflects the agencies' consideration of the jurisdictional
                concerns and limitations of SWANCC and Rapanos. The agencies have
                concluded that a provision that authorizes consideration of
                jurisdiction over tributaries that meet the relatively permanent or
                significant nexus standard when assessed based simply on connections to
                ``other waters'' would have too tenuous a connection to traditional
                navigable waters, interstate waters, or the territorial seas. The
                proposed rule retains the provisions of the 1986 regulations under
                which tributaries and adjacent wetlands to impoundments may be
                determined to be jurisdictional. The proposed change ensures that the
                impoundment of an ``other water'' does not change the jurisdictional
                status of tributaries or adjacent wetlands to it. This change reflects
                the agencies' consideration of the jurisdictional concerns and
                limitations of SWANCC and Rapanos. To be clear, an impoundment of an
                ``other water'' could still meet the relatively permanent standard or
                the significant nexus standard under the ``other waters'' provision;
                the impoundment simply would not retain its jurisdictional status under
                this impoundment provision.
                 Impoundments of jurisdictional waters were not addressed in the
                Rapanos decision and thus were not directly addressed by the agencies
                in the Rapanos Guidance. Under the proposed rule and pre-2015 practice,
                impounding waters can create traditional navigable waters, even if the
                waters that are impounded are not themselves traditional navigable
                waters. In addition, under the proposed rule impounding a water can
                create a relatively permanent water, even if the water that is being
                impounded is a non-relatively permanent water. For purposes of
                implementation, relatively permanent waters include waters where water
                is standing or ponded at least seasonally.
                 In the NWPR, the agencies changed their longstanding position that
                impoundments of jurisdictional waters remain jurisdictional and added
                new requirements for impoundments of jurisdictional waters to be
                considered ``waters of the United States.'' Specifically, under the
                NWPR, impoundments of jurisdictional waters had to either contribute
                surface water flow to a downstream jurisdictional water in a typical
                year or be inundated by flooding from a jurisdictional water in a
                typical year. In support of the NWPR's position that impounding a
                jurisdictional water could potentially create a non-jurisdictional
                feature, the agencies stated that ``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.'' 85 FR 22303, April 21, 2020.
                 The agencies disagree that jurisdiction over impoundments of
                ``waters of the United States'' reflects application of the principle
                of indelible navigability. The indelible navigation principle is
                applicable to Rivers and Harbors Act jurisdiction, not Clean Water Act
                jurisdiction, and holds that sudden or man-made changes to a water body
                or its navigable capacity do not alter the extent of Rivers and Harbors
                Act jurisdiction, and thus the area occupied or formerly occupied by
                that water body will always be subject to Rivers and Harbors Act
                jurisdiction even when the area is no longer a water.\46\ The agencies
                are not aware of any statement relying on that concept as the
                justification for its longstanding position that impoundments of
                ``waters of the United States'' remain ``waters of the United States''
                for Clean Water Act purposes, absent a legally authorized change of
                jurisdictional status under a Clean Water Act permit (such as a section
                404 permit authorizing creation of an excluded waste treatment system).
                ---------------------------------------------------------------------------
                 \46\ This principle has been incorporated in the Corps'
                definition of ``navigable waters of the United States'' for purposes
                of the Rivers and Harbors Act: ``A determination of navigability,
                once made, applies laterally over the entire surface of the water
                body, and is not extinguished by later actions or events which may
                impede or destroy navigable capacity.'' 33 CFR 329.4. The rule is
                expanded upon in 33 CFR 329.9 and 329.13: ``an area will remain
                `navigable in law,' even though no longer covered with water,
                whenever the change has occurred suddenly, or was caused by
                artificial forces intended to produce that change.'' EPA has no such
                regulations for purposes of implementing the Clean Water Act.
                ---------------------------------------------------------------------------
                 In departing from the agencies' longstanding position regarding the
                jurisdictional status of impoundments, the NWPR also stated that the
                agencies were unaware of any judicial decision ``that would prohibit
                the United States from consenting to defederalization of a water by a
                lawfully issued section 404 permit.'' 85 FR 22303, April 21, 2020. As
                noted above, the agencies recognize that a lawfully issued section 404
                permit, with any accompanying appropriate and practicable mitigation,
                can authorize filling of a ``water of the United States'' such that it
                is no longer a ``water of the United States.'' The ``impoundment''
                provision of the definition of ``waters of the United States'' simply
                retains jurisdiction over ``waters of the United States'' that are
                naturally or artificially impounded. If the impoundment occurs pursuant
                to a section 404 permit and the permit
                [[Page 69421]]
                authorizes the removal of the resulting impoundment from jurisdiction,
                such as in the case of the creation of a waste treatment system
                excluded from the ``waters of the United States'' by regulation, the
                impoundment would no longer be jurisdictional pursuant to this
                provision. On the flip side, an impoundment of a water that is not a
                ``water of the United States'' could become jurisdictional if, for
                example, the impounded water becomes navigable-in-fact and is thus
                covered under the traditional navigable waters provision of the rule.
                 Asserting Clean Water Act jurisdiction over impoundments also
                aligns with the scientific literature, as well as the agencies'
                scientific and technical expertise and experience, which confirm that
                impoundments have chemical, physical, and biological effects on
                downstream waters through surface or subsurface hydrologic connections.
                See Technical Support Document section IV.C. Indeed, berms, dikes, and
                similar features used to create impoundments typically do not block all
                water flow. Even dams, which are specifically designed and constructed
                to impound large amounts of water effectively and safely, generally do
                not prevent all water flow, but rather allow seepage under the
                foundation of the dam and through the dam itself. See, e.g.,
                International Atomic Energy Agency (``All dams are designed to lose
                some water through seepage.''); U.S. Bureau of Reclamation (``All dams
                seep, but the key is to control the seepage through properly designed
                and constructed filters and drains.''); Federal Energy Regulatory
                Commission 2005 (``Seepage through a dam or through the foundations or
                abutments of dams is a normal condition.''). Further, as an agency with
                expertise and responsibilities in engineering and public works, the
                Corps extensively studies water retention structures like berms,
                levees, and earth and rock-fill dams. The agency has found that all
                water retention structures are subject to seepage through their
                foundations and abutments. See, e.g., U.S. Army Corps of Engineers 1992
                at 1-1; U.S. Army Corps of Engineers 1993 at 1-1; U.S. Army Corps of
                Engineers 2004 at 6-1.
                 That said, there may be circumstances where an impoundment
                authorized under a section 404 permit completely and permanently severs
                surface or subsurface hydrologic connections. See ``U.S. Army Corps of
                Engineers Jurisdictional Determination Form Instructional Guidebook,''
                at 58. The agencies are considering whether there are certain types of
                impoundments--such as the example in the preceding sentence--that
                should be assessed under the ``other waters'' provision of the
                regulation. The agencies are seeking comment on this approach and
                accompanying implementation issues.
                5. Tributaries
                 The proposed rule retains the tributary provision of the 1986
                regulations, updated to reflect consideration of relevant Supreme Court
                decisions. The 1986 regulations defined ``waters of the United States''
                to include tributaries of traditional navigable waters, interstate
                waters, ``other waters,'' or impoundments. The proposed rule defines
                ``waters of the United States'' to include tributaries of traditional
                navigable waters, interstate waters, impoundments, or the territorial
                seas if the tributary meets either the relatively permanent standard or
                the significant nexus standard. The agencies solicit comment on all
                aspects of the tributary provision in this proposed rule.
                 The 1986 regulations include tributaries to interstate waters.
                Since interstate waters, like traditional navigable waters and the
                territorial seas, are foundational waters protected by the Clean Water
                Act, the agencies are proposing to protect them in a similar manner by
                providing that tributaries that meet either the relatively permanent
                standard or the significant nexus standard in relation to an interstate
                water are jurisdictional under the proposed rule. Ample scientific
                information makes clear that the health and productivity of rivers and
                lakes, including interstate waters, depends upon the functions provided
                by upstream tributaries. As discussed in section V.A.2.c of this
                preamble, tributaries, adjacent wetlands, and ``other waters'' that are
                relatively permanent or that have a significant nexus to downstream
                waters, including interstate waters, have important beneficial effects
                on those waters, and polluting or destroying these tributaries,
                adjacent wetlands, or ``other waters'' can harm downstream
                jurisdictional waters.
                 The agencies are proposing to delete the cross reference to ``other
                waters'' as a water to which tributaries may connect to be determined
                ``waters of the United States.'' This change reflects the agencies'
                consideration of the jurisdictional concerns and limitations of SWANCC
                and Rapanos. The agencies have concluded that a provision that
                authorizes consideration of jurisdiction over tributaries that meet the
                relatively permanent or significant nexus standard when assessed based
                simply on connections to ``other waters'' would have too tenuous a
                connection to traditional navigable waters, interstate waters, or the
                territorial seas. Rather, any such streams that are tributaries to
                jurisdictional ``other waters'' could be assessed themselves under the
                ``other waters'' category to determine if they meet the relatively
                permanent or significant nexus standard. Thus, a tributary to, for
                example, a lake that meets the significant nexus standard under the
                ``other waters'' provision could not be determined to be jurisdictional
                simply because it significantly affects the physical integrity of the
                lake; rather, the tributary would need to be assessed under the ``other
                waters'' provision for whether it significantly affects a traditional
                navigable water, interstate water, or the territorial seas.
                 Additionally, the agencies are proposing to add the territorial
                seas to the list of waters to which tributaries may connect to
                constitute a jurisdictional tributary because the territorial seas are
                explicitly protected by the Clean Water Act and are a type of
                traditional navigable water. The agencies are unaware of a legal basis
                for the 1986 regulation's failure to include the term ``territorial
                seas'' in the original tributaries provision of the rule. The proposed
                rule clarifies that tributaries to the territorial seas where they meet
                either the relatively permanent standard or the significant nexus
                standard fall within the definition of ``waters of the United States.''
                The territorial seas are explicitly covered by the Clean Water Act and
                they are also traditional navigable waters, so it is reasonable to
                protect tributaries to the territorial seas that meet either the
                relatively permanent standard or the significant nexus standard for the
                same reasons as tributaries to traditional navigable waters are
                covered.
                 Finally, the agencies are retaining the 1986 regulations' coverage
                of tributaries to impoundments, updated to include the requirement that
                the tributaries meet either the relatively permanent or significant
                nexus standard. As discussed above, the agencies' longstanding
                interpretation of the Clean Water Act is that a ``water of the United
                States'' remains a ``water of the United States'' even if it is
                impounded. Since the impoundment does not ``defederalize'' the ``water
                of the United States,'' see S.D. Warren at 379 n. 5, the agencies
                similarly interpret the Clean Water Act to continue to protect
                tributaries that fall within the tributary provision of the proposed
                rule upstream from the jurisdictional impoundment.
                 The agencies' longstanding interpretation of tributary for purposes
                [[Page 69422]]
                of Clean Water Act jurisdiction includes not only rivers and streams,
                but also lakes and ponds that flow directly or indirectly to downstream
                traditional navigable waters, interstate waters, the territorial seas,
                or impoundments of jurisdictional waters. See ``U.S. Army Corps of
                Engineers Jurisdictional Determination Form Instructional Guidebook,''
                at 8, 9. They may be at the headwaters of the tributary network (e.g.,
                a lake with no stream inlets that has an outlet to the tributary
                network) or farther downstream from the headwaters (e.g., a lake with
                both a stream inlet and a stream outlet to the tributary network). Once
                a water is determined to be a tributary, under the proposed rule the
                tributary must meet either the relatively permanent or significant
                nexus standards to be jurisdictional. Implementation of those standards
                is addressed in section V.D of this preamble.
                 Finally, the 1986 regulations do not contain a definition of
                tributary, and the agencies are not proposing a definition in this
                rule. However, the agencies have decades of experience implementing the
                1986 regulations. The agencies' longstanding interpretation of
                tributary for purposes of the definition of ``waters of the United
                States'' includes natural, man-altered, or man-made water bodies that
                flow directly or indirectly into a traditional navigable water,
                interstate water, or the territorial seas. See Rapanos Guidance at 6.
                Given the extensive human modification of watercourses and hydrologic
                systems throughout the country, it is often difficult to distinguish
                between natural watercourses and watercourses that are wholly or partly
                manmade or man-altered. Because natural, man-altered, and manmade
                tributaries provide many of the same functions, especially as conduits
                for the movement of water and pollutants to other tributaries or
                directly to traditional navigable waters, interstate waters, or the
                territorial seas, the agencies have interpreted the 1986 regulations to
                cover such tributaries. The OHWM, a term unchanged since 1977, see 41
                FR 37144 (July 19, 1977); and 33 CFR 323.3(c) (1978), defines the
                lateral limits of jurisdiction in non-tidal waters, provided the limits
                of jurisdiction are not extended by adjacent wetlands.
                 The agencies are proposing a different approach to tributaries than
                the NWPR's interpretation of that term. The NWPR defined ``tributary''
                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 was required to be
                perennial or intermittent in a typical year. 85 FR 22251, April 21,
                2020. The agencies are proposing an alternative to the NWPR's approach
                to tributaries for the reasons discussed in this section and in section
                V.B.3 of this preamble. The definition of ``tributary'' in the NWPR
                failed to advance the objective of the Clean Water Act and was
                inconsistent with scientific information about the important effects of
                ephemeral tributaries on the integrity of downstream traditional
                navigable waters. In addition, key elements of the NWPR's definition of
                tributary were extremely difficult to implement. All of these
                deficiencies are reflected in significant losses of federal protections
                on the ground. See section V.B.3 of this preamble.
                6. Territorial Seas
                 The Clean Water Act, the 1986 regulations, and the NWPR all include
                ``the territorial seas'' as a ``water of the United States.'' This
                proposed rule makes no changes to that provision, and would retain the
                territorial seas provision near the end of the list of jurisdictional
                waters, consistent with the 1986 regulations.
                 The Clean Water Act defines ``navigable waters'' to include ``the
                territorial seas'' at section 502(7). The Clean Water Act then defines
                the ``territorial seas'' in section 502(8) as ``the belt of the seas
                measured from the line of ordinary low water along that portion of the
                coast which is in direct contact with the open sea and the line marking
                the seaward limit of inland waters, and extending seaward a distance of
                three miles.''
                7. Adjacent Wetlands
                 As discussed further in section V.C.9.b of this preamble, in this
                proposed rule, the agencies are retaining the definition of
                ``adjacent'' unchanged from the 1986 regulations, which defined
                ``adjacent'' as follows: ``The term adjacent means bordering,
                contiguous, or neighboring. Wetlands separated from other waters of the
                United States by man-made dikes or barriers, natural river berms, beach
                dunes and the like are adjacent wetlands.'' In addition to retaining
                the definition of ``adjacent'' from the 1986 regulations, the proposed
                rule adds language to the adjacent wetlands provision regarding which
                adjacent wetlands can be considered ``waters of the United States'' to
                reflect the relatively permanent and significant nexus standards. As
                such, adjacent wetlands that would be jurisdictional under the proposed
                rule include wetlands adjacent to traditional navigable waters,
                interstate waters, or the territorial seas; wetlands adjacent to
                relatively permanent, standing, or continuously flowing impoundments or
                tributaries and that have a continuous surface connection to such
                waters; and wetlands adjacent to impoundments or tributaries that meet
                the significant nexus standard when the wetlands either alone or in
                combination with similarly situated waters in the region, significantly
                affect the chemical, physical, or biological integrity of foundational
                waters.
                 Under the proposed rule, the agencies would continue, as they did
                under the 1986 regulations and the Rapanos Guidance, to assert
                jurisdiction over wetlands adjacent to traditional navigable waters
                without need for further assessment. Indeed, the Rapanos decision did
                not affect the scope of jurisdiction over wetlands that are adjacent to
                traditional navigable waters because at least five justices agreed that
                such wetlands are ``waters of the United States.'' See Rapanos, 547
                U.S. at 780 (Kennedy, J., concurring) (``As applied to wetlands
                adjacent to navigable-in-fact waters, the Corps' conclusive standard
                for jurisdiction rests upon a reasonable inference of ecologic
                interconnection, and the assertion of jurisdiction for those wetlands
                is sustainable under the Act by showing adjacency alone.''), id. at 810
                (Stevens, J. dissenting) (``Given that all four Justices who have
                joined this opinion would uphold the Corps' jurisdiction in both of
                these cases--and in all other cases in which either the plurality's or
                Justice Kennedy's test is satisfied--on remand each of the judgments
                should be reinstated if either of those tests is met.''); see also
                Riverside Bayview, 474 U.S. 121, 134 (``[T]he Corps' ecological
                judgment about the relationship between waters and their adjacent
                wetlands provides an adequate basis for a legal judgment that adjacent
                wetlands may be defined as waters under the Act.''); Rapanos Guidance
                at 5. Moreover, ample scientific information makes clear that the
                health and productivity of rivers and lakes, including foundational
                waters, depends upon the functions provided by upstream tributaries,
                adjacent wetlands, and ``other waters.''
                 Under the proposed rule the agencies would also define ``waters of
                the United States'' to include wetlands adjacent to the territorial
                seas as they did under the 1986 regulations without need for further
                assessment; the territorial seas are categorically protected under the
                [[Page 69423]]
                Clean Water Act and are a type of traditional navigable water.
                 The 1986 regulations also include wetlands adjacent to interstate
                waters and since interstate waters, like traditional navigable waters
                and the territorial seas, are foundational waters protected by the
                Clean Water Act, under the proposed rule the agencies would define
                ``waters of the United States'' to include wetlands adjacent to
                interstate waters without need for further assessment.
                 The proposed rule also would add the relatively permanent standard
                and the significant nexus standard to the 1986 regulations' adjacent
                wetlands provisions for wetlands adjacent to impoundments and
                tributaries. The relatively permanent standard and the significant
                nexus standard are independent of each other and this provision in the
                proposed rule is structured so that jurisdiction over wetlands adjacent
                to jurisdictional waters would be determined using the same standard
                under which the impoundment or tributary would be determined to be
                jurisdictional. For example, a wetland adjacent to a relatively
                permanent tributary must have a continuous surface connection to the
                tributary to be jurisdictional under the relatively permanent standard.
                Similarly, under the significant nexus standard an adjacent wetland and
                a tributary would be assessed for whether the waters either alone or in
                combination with similarly situated waters in the region, significantly
                affect the chemical, physical, or biological integrity of foundational
                waters. Wetlands adjacent to relatively permanent tributaries but that
                lack a continuous surface connection to such waters would then be
                assessed under the significant nexus, along with the tributary.
                 The agencies are proposing to delete the cross reference to ``other
                waters'' as a water to which wetlands may be adjacent to be determined
                ``waters of the United States.'' This change reflects the agencies'
                consideration of the jurisdictional concerns and limitations of SWANCC
                and Rapanos. The agencies have concluded that a provision that
                authorizes consideration of jurisdiction over adjacent wetlands that
                meet the relatively permanent or significant nexus standard when
                assessed based simply on connections to ``other waters'' would have too
                tenuous a connection to traditional navigable waters, interstate
                waters, or the territorial seas. Rather, any such wetlands that are
                adjacent to jurisdictional ``other waters'' could be assessed
                themselves under the ``other waters'' category to determine if they
                meet the relatively permanent or significant nexus standard. Thus, a
                wetland adjacent to, for example, a lake that meets the significant
                nexus standard under the ``other waters'' provision could not be
                determined to be jurisdictional simply because it significantly affects
                the physical integrity of the lake; rather, the wetland would need to
                be assessed under the ``other waters'' provision for whether it
                significantly affects a traditional navigable water, interstate water,
                or the territorial seas.
                 Finally, the agencies are retaining the 1986 regulations' coverage
                of wetlands adjacent to impoundments and wetlands adjacent to
                tributaries to impoundments, updated to include the requirement that
                the wetlands meet either the relatively permanent or significant nexus
                standard. As discussed above, the agencies' longstanding interpretation
                of the Clean Water Act is that a ``water of the United States'' remains
                a ``water of the United States'' even if it is impounded. Since the
                impoundment does not ``defederalize'' the ``water of the United
                States,'' see S.D. Warren 379 n.5, the agencies similarly interpret the
                Clean Water Act to continue to protect wetlands adjacent to the
                jurisdictional impoundment and adjacent to jurisdictional tributaries
                to the impoundment.
                 For wetlands adjacent to impoundments of jurisdictional waters,
                such waters were not addressed in the Rapanos decision and thus were
                not addressed by the agencies in the Rapanos Guidance. Under the
                proposed rule, the agencies would assess if the impoundment (i.e., the
                water identified in paragraph (a)(4) of the proposed rule) itself is or
                is not a relatively permanent, standing, or continuously flowing body
                of water. If it is, the agencies would assess if the adjacent wetlands
                have a continuous surface connection with the impoundment. Wetlands
                adjacent to relatively permanent impoundments and that lack a
                continuous surface connection to the impoundment and wetlands adjacent
                to non-relatively permanent impoundments would be considered under the
                significant nexus standard. The agencies are soliciting comment on the
                approach in the proposed rule for wetlands adjacent to impoundments and
                if they should instead consider alternative approaches for wetlands
                adjacent to impoundments, such as determining which jurisdictional
                standard should apply based on the water that is being impounded (e.g.,
                if a non-relatively permanent tributary is impounded, the agencies
                would assess the wetlands adjacent to the impoundment under the
                significant nexus standard, even if the impoundment itself contains
                standing water at least seasonally).
                 Finally, the agencies retain in the proposed rule the parenthetical
                from the 1986 regulations that limited the scope of jurisdictional
                adjacent wetlands under (a)(7) to wetlands adjacent to waters ``(other
                than waters that are themselves wetlands).'' Under this provision, a
                wetland is not jurisdictional simply because it is adjacent to another
                adjacent wetland. See Universal Welding & Fabrication, Inc. v. United
                States Army Corps of Engineers, 708 Fed. Appx. 301 (9th Cir. 2017)
                (``Despite the subject wetland's adjacency to another wetland, the
                Corps determined that its regulatory authority was not precluded by the
                parenthetical language within [section] 328.3(a)(7), which it
                interpreted as prohibiting the exercise of jurisdiction over a wetland
                only if based upon that wetland's adjacency to another wetland.''). The
                provision has created confusion, as some have argued that a wetland
                that is indeed adjacent to a jurisdictional tributary should not be
                determined to be a ``water of the United States'' simply because
                another adjacent wetland was located between the adjacent wetland and
                the tributary. Some have even suggested that the parenthetical flatly
                excluded all wetlands that are adjacent to other wetlands, regardless
                of any other considerations. These interpretations are inconsistent
                with the agencies' intent and longstanding interpretation of the
                parenthetical. Id. at 303 (holding the Corps' interpretation is ``the
                most reasonable reading of the regulation's text'' and ``[t]o the
                extent that Plaintiff argues that all wetlands adjacent to other
                wetlands fall outside the Corps' regulatory authority, regardless of
                their adjacency to a non-wetland water that would otherwise render them
                jurisdictional, we conclude that this reading is unsupported by the
                regulation's plain language.''). In addition, under the 1986
                regulations and longstanding practice, wetlands adjacent to an
                interstate wetland or wetlands adjacent to tidal wetlands, which are
                traditional navigable waters, are jurisdictional. Because this
                provision has caused confusion at times for the public and the
                regulated community, the agencies are requesting comment on whether to
                remove the parenthetical ``(other than waters that are themselves
                wetlands)'' because it is confusing and unnecessary.
                 The agencies are proposing a different approach to adjacent
                wetlands than the NWPR's interpretation of that term. The NWPR defined
                ``adjacent wetlands'' to be those wetlands that abut
                [[Page 69424]]
                jurisdictional waters and those non-abutting wetlands that are (1)
                ``inundated by flooding'' from a jurisdictional water in a typical
                year, (2) physically separated from a jurisdictional water only by
                certain natural features (e.g., a berm, bank, or dune), or (3)
                physically separated from a jurisdictional water by an artificial
                structure that ``allows for a direct hydrologic surface connection''
                between the wetland and the jurisdictional water in a typical year. 85
                FR 22251, April 21, 2020. Wetlands that do not have these types of
                connections to other waters were not jurisdictional.
                 The agencies are not proposing the NWPR's approach to adjacent
                wetlands for the reasons discussed in this section and in section V.B.3
                of this preamble. Specifically, the definition of ``adjacent wetlands''
                in the NWPR failed to advance the objective of the Clean Water Act and
                was inconsistent with scientific information about the important
                effects of wetlands that do not abut jurisdictional waters and that
                lack evidence of surface water to such waters on the integrity of
                downstream foundational waters. In addition, key elements of that
                definition were extremely difficult to implement. These deficiencies
                are reflected in significant losses of federal protections on the
                ground. See section V.B.3 of this preamble.
                8. Exclusions
                 The agencies are also proposing to repromulgate two longstanding
                exclusions from the definition of ``waters of the United States'': the
                exclusion for prior converted cropland and the exclusion for waste
                treatment systems. These longstanding exclusions from the definition
                provide important clarity.\47\ The agencies are not proposing to codify
                the list of exclusions established by the NWPR or the 2015 Clean Water
                Rule, as they view the two proposed regulatory exclusions as most
                consistent with the goal of this proposed rule to return to the
                familiar and longstanding framework that will ensure Clean Water Act
                protections, informed by relevant Supreme Court decisions. Moreover, as
                discussed in section V.D.1.b of this preamble, the agencies would
                expect to implement the proposed rule consistent with longstanding
                practice, pursuant to which they have generally not asserted
                jurisdiction over certain other features. The agencies solicit comment
                on this approach to codifying and implementing exclusions.
                ---------------------------------------------------------------------------
                 \47\ The agencies note that they have never interpreted
                groundwater be a ``water of the United States'' under the Clean
                Water Act. See, e.g., 80 FR 37099-37100 (explaining that the
                agencies have never interpreted ``waters of the United States'' to
                include groundwater); 85 FR 22278, April 21, 2020 (explaining that
                the agencies have never interpreted ``waters of the United States''
                to include groundwater). The proposed rule makes no change to that
                longstanding interpretation. This interpretation was recently
                confirmed by the U.S. Supreme Court. Maui, 140 S.Ct. at 1472 (``The
                upshot is that Congress was fully aware of the need to address
                groundwater pollution, but it satisfied that need through a variety
                of state-specific controls. Congress left general groundwater
                regulatory authority to the States; its failure to include
                groundwater in the general EPA permitting provision was
                deliberate.'') While groundwater itself is not a ``water of the
                United States,'' discharges of pollutants to groundwater that reach
                a jurisdictional surface require a NPDES permit where the discharge
                through groundwater is the ``functional equivalent'' of a direct
                discharge from the point source into navigable waters. Maui, 140
                S.Ct. at 1468.
                ---------------------------------------------------------------------------
                a. Prior Converted Cropland
                 The proposed rule would repromulgate the regulatory exclusion for
                prior converted cropland first codified in 1993, which provided that
                prior converted cropland is ``not `waters of the United States,''' and
                that ``for purposes of the Clean Water Act, the final authority
                regarding Clean Water Act jurisdiction remains with EPA,''
                notwithstanding any other Federal agency's determination of an area's
                status. 58 FR 45008, 45036. This proposal would restore longstanding
                and familiar practice under the pre-2015 regulatory regime and
                generally maintain consistency between the agencies' implementation of
                the Clean Water Act and the U.S. Department of Agriculture's (USDA)
                implementation of the Food Security Act, providing certainty to farmers
                seeking to conserve and protect land and waters pursuant to federal
                law.
                 The concept of prior converted cropland originates in the wetland
                conservation provisions of the Food Security Act of 1985, 16 U.S.C.
                3801 et seq. These provisions were intended to disincentivize the
                conversion of wetlands to croplands. Under the Food Security Act
                wetland conservation provisions, farmers who convert wetlands to make
                possible the production of an agricultural commodity crop lose
                eligibility for certain USDA program benefits. If a farmer had
                converted wetlands to cropland prior to December 23, 1985, then the
                land is considered prior converted cropland and the farmer does not
                lose eligibility for benefits. USDA defines prior converted cropland
                for Food Security Act purposes in its regulations at 7 CFR part 12. See
                7 CFR 12.2(a) and 12.33(b).
                 In 1993, EPA and the Corps codified an exclusion for prior
                converted croplands from the definition of ``waters of the United
                States'' regulated pursuant to the Clean Water Act. The exclusion
                stated, ``[w]aters of the United States do not include prior converted
                cropland. Notwithstanding the determination of an area's status as
                prior converted cropland by any other Federal agency, for the purposes
                of the Clean Water Act, the final authority regarding Clean Water Act
                jurisdiction remains with EPA.'' 58 FR 45008, 45036; 33 CFR 328.3(a)(8)
                (1994); 40 CFR 230.3(s) (1994). The preamble stated that EPA and the
                Corps would interpret prior converted cropland consistent with the
                definition in the National Food Security Act Manual (NFSAM) published
                by the USDA Soil Conservation Service, now known as USDA's Natural
                Resource Conservation Service (NRCS). 58 FR 45031. It cited USDA's
                definition of prior converted cropland to mean ``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. PC [prior converted] cropland is inundated for no more than
                14 consecutive days during the growing season and excludes pothole or
                playa wetlands.'' Id.
                 The purpose of the exclusion, as EPA and the Corps explained in the
                1993 preamble, was to ``codify existing policy,'' as the agencies had
                not been implementing the Act to include prior converted cropland, and
                to ``help achieve consistency among various federal programs affecting
                wetlands.'' Id. The preamble further stated that excluding prior
                converted cropland from ``waters of the United States'' was consistent
                with protecting aquatic resources because ``[prior converted cropland]
                has been significantly modified so that it no longer exhibits its
                natural hydrology or vegetation. Due to this manipulation, [prior
                converted] cropland no longer performs the functions or has values that
                the area did in its natural condition. PC cropland has therefore been
                significantly degraded through human activity and, for this reason,
                such areas are not treated as wetlands under the Food Security Act.
                Similarly, in light of the degraded nature of these areas, we do not
                believe that they should be treated as wetlands for the purposes of the
                CWA.'' Id. at 45032.
                 The 1993 preamble stated that, consistent with the NFSAM, an area
                would lose its status as prior converted cropland if the cropland is
                ``abandoned,'' meaning that crop production ceases and the area reverts
                to a wetland state. Id. at 45033. Specifically, the preamble states
                that prior converted cropland that now
                [[Page 69425]]
                meets wetland criteria will be considered abandoned unless ``once in
                every five years it has been used for the production of an agricultural
                commodity, or the area has been used and will continue to be used for
                the production of an agricultural commodity in a commonly used rotation
                with aquaculture, grasses, legumes, or pasture production.'' Id. at
                45034.
                 Three years later, the Federal Agriculture Improvement and Reform
                Act of 1996 amended the Food Security Act and changed this
                ``abandonment'' principle, replacing it with a new approach referred to
                as ``change in use.'' See Public Law 104-127, 110 Stat. 888 (1996).
                Under the 1996 amendments, an area retains its status as prior
                converted cropland for purposes of the wetland conservation provisions
                so long as it continues to be used for agricultural purposes. H.R.
                Conf. Rep. No. 104-494, at 380 (1996). EPA and the Corps did not
                address the 1996 amendments in rulemaking. In 2005, the Corps and NRCS
                issued a joint Memorandum to the Field in an effort to again align the
                Clean Water Act section 404 program with the Food Security Act by
                adopting the principle that a wetland can lose prior converted cropland
                status following a ``change in use.'' \48\ The Memorandum stated, ``[a]
                certified PC determination made by NRCS remains valid as long as the
                area is devoted to an agricultural use. If the land changes to a non-
                agricultural use, the PC determination is no longer applicable and a
                new wetland determination is required for CWA purposes.'' It defined
                ``agricultural use'' as ``open land planted to an agricultural crop,
                used for the production of food or fiber, used for haying or grazing,
                left idle per USDA programs, or diverted from crop production to an
                approved cultural practice that prevents erosion or other
                degradation.''
                ---------------------------------------------------------------------------
                 \48\ This 2005 joint Memorandum was rescinded on January 28,
                2020. See https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/4288.
                ---------------------------------------------------------------------------
                 One district court set aside the Corps' adoption of change in use
                on the grounds that it was a substantive change in Clean Water Act
                implementation that the agencies had not issued through notice and
                comment rulemaking. New Hope Power Co. v. U.S. Army Corps of Eng'rs,
                746 F. Supp. 2d 1272, 1282 (S.D. Fla. 2010). The court explained,
                ``prior to issuance of the policy, prior converted cropland that was
                shifted to non-agricultural use was treated as exempt. Following [its
                issuance], the opposite was true.'' Id. Following New Hope Power, the
                agencies did not implement change in use in areas subject to the
                court's jurisdiction.
                 The NWPR provided a definition of prior converted cropland for
                purposes of the Clean Water Act for the first time since 1993.
                Generally speaking, the NWPR's approach to prior converted cropland
                significantly reduced the likelihood that prior converted cropland will
                ever lose its excluded status. The NWPR provided that an area remains
                prior converted cropland for purposes of the Clean Water Act unless the
                area is abandoned and has reverted to wetlands, defining abandonment to
                occur when prior converted cropland ``is not used for, or in support
                of, agricultural purposes at least once in the immediately preceding
                five years.'' 85 FR 22339, April 21, 2020; 33 CFR 328.3(c)(9). The NWPR
                then presented a broad interpretation of ``agricultural purposes,''
                including but not limited to crop production, haying, grazing, idling
                land for conservation uses (such as habitat; pollinator and wildlife
                management; and water storage, supply, and flood management);
                irrigation tailwater storage; crawfish farming; cranberry bogs;
                nutrient retention; and idling land for soil recovery following natural
                disasters such as hurricanes and drought. 85 FR 22321, April 21, 2020.
                Under the NWPR, prior converted cropland maintained its excluded status
                if it is used at least once in the five years preceding a
                jurisdictional determination for any of these agricultural purposes.
                Given the breadth of ``agricultural purposes'' under the NWPR, former
                cropland that reverts to wetlands otherwise meeting the definition of
                ``waters of the United States'' could maintain its excluded prior
                converted cropland status simply by, for example, being grazed or idled
                for habitat conservation once in five years. These wetlands could then
                be filled without triggering any Clean Water Act regulatory protection.
                 The NWPR's imprecise language in defining prior converted cropland
                for purposes of the Clean Water Act potentially extended prior
                converted cropland status far beyond those areas USDA considers prior
                converted cropland for purposes of the Food Security Act. Specifically,
                USDA's regulation defining prior converted cropland refers to
                conversion that makes possible production of an ``agricultural
                commodity,'' which provides for annual tilling of the soil, while the
                NWPR defined prior converted cropland to encompass any area used to
                produce an ``agricultural product,'' a term not used in the regulations
                that therefore introduces significant ambiguity and further
                distinguishes the Clean Water Act's prior converted cropland exclusion
                from USDA's approach. Compare 7 CFR 12.2(a) with 33 CFR 328.3(c)(9).
                The NWPR's definition provided that the agencies would recognize prior
                converted cropland designations made by USDA, 33 CFR 328.3(c)(9), but
                the list of examples that the NWPR provided for ``agricultural
                product'' suggests the term is significantly broader than the USDA's
                exclusion for land used for ``commodity crops.'' The absence of a
                definition for the term ``agricultural product'' or any explanation as
                to how it is different from a ``commodity crop'' undermined
                transparency and the original purpose of the exclusion, which was to
                help achieve consistency among various federal programs affecting
                wetlands. See 58 FR 45031.
                 The proposed rule would restore the exclusion's original purpose of
                maintaining consistency among federal programs addressing wetlands,
                while furthering the objective of the Clean Water Act. Id. at 45031-32.
                As was the case between 1993 and promulgation of the NWPR, the agencies
                propose that, for purposes of the Clean Water Act exclusion, a
                landowner may demonstrate that a water retains its prior converted
                cropland status through a USDA prior converted cropland certification.
                See id. at 45033 (``recognizing [NRCS]'s expertise in making these
                [prior converted] cropland determinations, we will continue to rely
                generally on determinations made by [NRCS].''). The agencies' proposal
                would maintain the provision promulgated in 1993 that EPA retains final
                authority to determine whether an area is subject to the requirements
                of the Clean Water Act. Moreover, by limiting the implementation of the
                exclusion to areas with a USDA prior converted cropland certification,
                the exclusion would only encompass significantly degraded waters that
                no longer perform the functions of the waters in their natural
                condition. See id. at 45032. The proposal would therefore align the
                exclusion with the objective of the Clean Water Act, to restore and
                maintain the integrity of the nation's waters, consistent with the
                agencies' intent in 1993.
                 The agencies request comment as to whether any other changes could
                enhance consistency between the prior converted cropland status under
                the Food Security Act and the exclusion of prior converted cropland
                under the Clean Water Act, while effectuating the goals of the Clean
                Water Act. One way of increasing consistency could be to implement the
                text of the original prior
                [[Page 69426]]
                converted cropland exclusion consistent with USDA's current and
                longstanding approach, outlined in USDA's final rule addressing the
                Highly Erodible Land and Wetland Conservation provisions of the Food
                Security Act of 1985. 85 FR 53137 (August 28, 2020). Pursuant to this
                approach, cropland would lose its exclusion if it ``changes use,'' as
                USDA interprets that term. See 61 FR 47036 (September 6, 1996); 7 CFR
                12.30(c)(6) (``As long as the affected person is in compliance with the
                wetland conservation provision of this part, and as long as the area is
                devoted to the use and management of the land for production of food,
                fiber, or horticultural crops, a certification made under this section
                will remain valid and in effect until such time as the person affected
                by the certification requests review of the certification by NRCS.'').
                This approach would fulfill the exclusion's purpose of ensuring
                consistency among federal programs affecting wetlands. See 58 FR 45031.
                Alternatively, the agencies request comment as to whether to implement
                the exclusion consistent with the interpretation in the 1993 preamble,
                under which an area only loses its prior converted cropland status if
                the cropland is ``abandoned,'' meaning that commodity crop production
                ceases and the area reverts to a wetland state. See id. at 45033. Under
                this approach, an area that has been designated as prior converted
                cropland and has not reverted to a wetland state (meaning the area
                would not meet the definition of wetland) would not become a ``water of
                the United States'' regardless of agricultural activity. However, an
                area which has been designated as prior converted cropland and has
                reverted to a wetland state could be reviewed for a potential loss of
                the exclusion status under the Clean Water Act. The following scenarios
                provide examples of the way in which the exclusion could cease
                following either ``abandonment'' or ``change in use.''
                 First, if the agencies were to apply the abandonment principle, the
                reverted wetland area would only regain jurisdictional status if:
                 (1) The area had not been used for the production of an
                agricultural commodity, or the area had not been used and would
                continue to not be used for the production of an agricultural commodity
                in a commonly used rotation with aquaculture, grasses, legumes, or
                pasture production, at least once in every five years and
                 (2) the area reverts to a wetland that meets the definition of
                ``waters of the United States.''
                 Under the abandonment principle, if an agricultural producer with
                an area designated as prior converted cropland fails to produce an
                agricultural commodity, or the area fails to be used in rotation as
                described above, for a period of six years, and the prior converted
                cropland area reverts to wetland, the wetland would lose the benefit of
                the exclusion and discharges of a pollutant to the wetland would be
                subject to regulation under the Clean Water Act if it meets the
                definition of ``waters of the United States'' and activities taking
                place on it are not otherwise exempt. In a second example of
                abandonment, if an agricultural producer with an area designated as
                prior converted cropland produces an agricultural commodity two years
                prior to selling its property for a residential development, the area
                retains its prior converted cropland designation even if it reverts to
                wetlands that would otherwise meet the definition of ``waters of the
                United States.'' In this example, discharges of dredged or fill
                material from the construction of the residential development into the
                wetlands which occurred within the three years remaining out of the
                five-year timeframe allowed before the abandonment provision would be
                triggered would not require authorization under Clean Water Act section
                404.
                 Alternatively, if the agencies were to apply the change in use
                principle in the second example scenario above, the reverted wetland
                area could regain jurisdictional status if it were subject to a change
                in use, meaning the area is no longer available for production of an
                agricultural commodity, and if the reverted wetland met the definition
                of ``waters of the United States.'' In that scenario, if an
                agricultural producer with an area certified by NRCS as prior converted
                cropland produces an agricultural commodity two years prior to selling
                their property for a residential development, the prior converted
                cropland designation would no longer apply when the area is no longer
                available for the production of an agricultural commodity crop. If the
                prior converted cropland area reverts to wetlands and meets the
                definition of ``waters of the United States'' the discharge of dredged
                or fill material from the construction of the residential development
                would require authorization under Clean Water Act section 404. The
                agencies hope this discussion and set of examples will illuminate the
                differences between interpreting the prior converted cropland
                designation to cease upon abandonment as opposed to change in use, to
                allow for input to best inform the agencies' path forward.
                 The agencies solicit comment on alternative approaches to the prior
                converted cropland exclusion as well, including retaining the
                definition of prior converted cropland in the NWPR. While the agencies
                have concerns with that definition, as discussed above, the agencies
                request comment with regard to those concerns and whether they should
                nonetheless retain the NWPR's interpretation that prior converted
                cropland retains its designation so long as it has been used for
                agricultural purposes at least once in the preceding five years, and
                that agricultural purposes include crop production, haying, grazing,
                idling land for conservation uses (such as habitat; pollinator and
                wildlife management; and water storage, supply, and flood management);
                irrigation tailwater storage; crawfish farming; cranberry bogs;
                nutrient retention; and idling land for soil recovery following natural
                disasters like hurricanes and drought. Finally, the agencies request
                comment as to whether certain specific types of documentation aside
                from USDA certification should be considered sufficient to demonstrate
                that an area is prior converted cropland.
                b. Waste Treatment System Exclusion
                 The agencies are also proposing to retain the waste treatment
                system exclusion from the 1986 regulations and return to the
                longstanding version of the exclusion that the agencies have
                implemented for decades. Specifically, the proposed rule provides that
                ``[w]aste treatment systems, including treatment ponds or lagoons,
                designed to meet the requirements of the Clean Water Act are not waters
                of the United States.'' This language is the same as the agencies' 1986
                regulation's version of the waste treatment system exclusion, with a
                ministerial change to delete the exclusion's cross-reference to a
                definition of ``cooling ponds'' that no longer exists in the Code of
                Federal Regulations, and the addition of a comma that clarifies the
                agencies' longstanding implementation of the exclusion as applying only
                to systems that are designed to meet the requirements of the Act.\49\
                ---------------------------------------------------------------------------
                 \49\ The NWPR defined a waste treatment system as ``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).'' 85 FR 22339, April 21, 2020.
                ---------------------------------------------------------------------------
                 EPA first promulgated the waste treatment system exclusion in a
                1979
                [[Page 69427]]
                notice-and-comment rulemaking revising the definition of ``waters of
                the United States'' in the agency's NPDES regulations. 44 FR 32854
                (June 7, 1979). A ``frequently encountered comment'' was that ``waste
                treatment lagoons or other waste treatment systems should not be
                considered waters of the United States.'' Id. at 32858. EPA agreed,
                except as to cooling ponds that otherwise meet the criteria for
                ``waters of the United States.'' Id. The 1979 revised definition of
                ``waters of the United States'' thus provided that ``waste treatment
                systems (other than cooling ponds meeting the criteria of this
                paragraph) are not waters of the United States.'' Id. at 32901 (40 CFR
                122.3(t) (1979)).
                 The following year, EPA revised the exclusion, but again only in
                its NPDES regulations, to clarify its application to treatment ponds
                and lagoons and to specify the type of cooling ponds that fall outside
                the scope of the exclusion. 45 FR 33290, 33298 (May 19, 1980). EPA
                further decided to revise this version of the exclusion to clarify that
                ``treatment systems created in [waters of the United States] or from
                their impoundment remain waters of the United States,'' while
                ``[m]anmade waste treatment systems are not waters of the United
                States.'' Id. The revised exclusion read: ``[w]aste treatment systems,
                including treatment ponds or lagoons designed to meet the requirements
                of CWA (other than cooling ponds as defined in 40 CFR [section]
                423.11(m) which also meet the criteria of this definition) are not
                waters of the United States.'' The provision further provided that the
                exclusion ``applies only to manmade bodies of water which neither were
                originally created in waters of the United States (such as a disposal
                area in wetlands) nor resulted from the impoundment of waters of the
                United States.'' 45 FR 33424 (40 CFR 122.3).
                 Two months following this revision, EPA took action to ``suspend[ ]
                a portion'' of the waste treatment system exclusion in its NPDES
                regulations in response to concerns raised in petitions for review of
                the revised definition of ``waters of the United States.'' 45 FR 48620
                (July 21, 1980). EPA explained that industry petitioners objected to
                limiting the waste treatment system exclusion to manmade features,
                arguing that the revised exclusion ``would require them to obtain
                permits for discharges into existing waste treatment systems, such as
                power plant ash ponds, which had been in existence for many years.''
                Id. at 48620. The petitioners argued that ``[i]n many cases, . . . EPA
                had issued permits for discharges from, not into, these systems.'' Id.
                Agreeing that the regulation ``may be overly broad'' and ``should be
                carefully re-examined,'' EPA announced that it was ``suspending [the]
                effectiveness'' of the sentence limiting the exclusion to manmade
                bodies of water. Id. EPA then stated that it ``intend[ed] promptly to
                develop a revised definition and to publish it as a proposed rule for
                public comment,'' after which the agency would decide whether to
                ``amend the rule, or terminate the suspension.'' Id.
                 In 1983, EPA republished the waste treatment system exclusion in
                its NPDES regulations with a note explaining that the agency's July
                1980 action had ``suspended until further notice'' the sentence
                limiting the exclusion to manmade bodies of water, and that the 1983
                action ``continue[d] that suspension.'' 48 FR 14146, 14157 (April 1,
                1983) (40 CFR 122.2) (1984). EPA subsequently omitted the exclusion's
                suspended sentence altogether in revising the definition of ``waters of
                the United States'' in other parts of the Code of Federal Regulations.
                See, e.g., 53 FR 20764, 20774 (June 6, 1988) (revising EPA's section
                404 program definitions at 40 CFR 232.2).
                 Separately, the Corps published an updated definition of ``waters
                of the United States'' in 1986. This definition contained the waste
                treatment system exclusion, but it likewise did not include the
                exclusion's suspended sentence: ``Waste treatment systems, including
                treatment ponds or lagoons designed to meet the requirements of CWA
                (other than cooling ponds as defined in 40 CFR 123.11(m) which also
                meet the criteria of this definition) are not waters of the United
                States.'' 51 FR 41250 (November 13, 1986); 33 CFR 328.3 (1987).
                 Later revisions to the definition of cooling ponds rendered the
                exclusion's cross-reference to 40 CFR 123.11(m) outdated. See 47 FR
                52290, 52291, 52305 (November 19, 1982) (revising regulations related
                to cooling waste streams and deleting definition of cooling ponds). In
                this rulemaking, the agencies are proposing to delete this obsolete
                cross-reference, consistent with other recent rulemakings addressing
                the definition of ``waters of the United States.'' \50\
                ---------------------------------------------------------------------------
                 \50\ 85 FR 22250, 22325 (April 21, 2020) (``One ministerial
                change [to the waste treatment system exclusion] is the deletion of
                a cross-reference to a definition of ``cooling ponds'' that no
                longer exists in the Code of Federal Regulations.''); 80 FR 37054,
                37097 (June 29, 2015) (``One ministerial change [to the waste
                treatment system exclusion] is the deletion of a cross-reference in
                the current language to an EPA regulation that no longer exists.'').
                ---------------------------------------------------------------------------
                 The proposed rule also deletes the suspended sentence in EPA's
                NPDES regulations limiting application of the exclusion to manmade
                bodies of water. The suspended sentence, which appeared only in the
                version of the waste treatment system exclusion contained in EPA's
                NPDES regulations (40 CFR 122.2) prior to the NWPR, states: ``This
                exclusion applies only to manmade bodies of water which neither were
                originally created in waters of the United States (such as disposal
                area in wetlands) nor resulted from the impoundment of waters of the
                United States.'' As discussed above, EPA suspended this sentence
                limiting application of the exclusion in 1980. As a result, EPA has not
                limited application of the waste treatment system exclusion to manmade
                bodies of water for over four decades. The proposed rule maintains the
                NWPR's deletion of the suspended sentence in EPA's NPDES regulations
                and is thus consistent with the other versions of the exclusion found
                in EPA's and the Corps' 1986 regulations and EPA's decades-long
                practice implementing the exclusion under the 1986 regulations.
                 Indeed, for decades, both agencies have not limited application of
                the exclusion to manmade bodies of water. This longstanding approach to
                excluding waste treatment systems--including those that are not manmade
                bodies of water--is a reasonable and lawful exercise of the agencies'
                authority to determine the scope of ``waters of the United States,''
                see Ohio Valley Envtl. Coal. v. Aracoma Coal Co., 556 F.3d 177, 212
                (4th Cir. 2009) (upholding the waste treatment system exclusion as a
                lawful exercise of the agencies' ``authority to determine which waters
                are covered by the CWA''). For all of these reasons, the agencies are
                proposing to delete the suspended sentence referenced above. The
                agencies solicit comment on this approach.
                 Further, consistent with the 1986 regulations, the proposed rule
                provides that a waste treatment system must be ``designed to meet the
                requirements of the Clean Water Act.'' A waste treatment system may be
                ``designed to meet the requirements of the Clean Water Act'' where, for
                example, it is constructed pursuant to a Clean Water Act section 404
                permit, Ohio Valley Envtl. Coalition v. Aracoma Coal Co., 556 F.3d 177,
                214-15 (4th Cir. 2009), or where it is ``incorporated in an NPDES
                permit as part of a treatment system,'' N. Cal. River Watch v. City of
                Healdsburg, 496 F.3d 993, 1001 (9th Cir. 2007).
                 To be clear, the exclusion does not free a discharger from the need
                to comply with the Clean Water Act for pollutants discharged from a
                waste treatment system to a water of the
                [[Page 69428]]
                United States; only discharges into the waste treatment system are
                excluded from the Act's requirements. As such, any entity would need to
                comply with the Clean Water Act by obtaining a section 404 permit for a
                new waste treatment system constructed in ``waters of the United
                States,'' and a section 402 permit for discharges of pollutants from a
                waste treatment system into ``waters of the United States.'' Further,
                consistent with the agencies' general practice implementing the
                exclusion, under the proposed rule, a waste treatment system that is
                abandoned or otherwise ceases to serve the treatment function for which
                it was designed would not continue to qualify for the exclusion and
                could be deemed jurisdictional if it otherwise meets the proposed
                rule's definition of ``waters of the United States.''
                 The agencies are aware of concerns raised by some stakeholders that
                features subject to the waste treatment system exclusion could be used
                by any party to dispose waste or discharge pollutants with abandon. In
                this proposal, the agencies are clarifying that for waters that would
                otherwise meet the proposed rule's definition of ``waters of the United
                States,'' the agencies' intent, consistent with prior practice, is that
                the waste treatment system exclusion is generally available only to the
                permittee using the system for the treatment function for which such
                system was designed. Relatedly, the agencies are also clarifying that,
                consistent with the agencies' longstanding practice, a waste treatment
                system does not sever upstream waters from Clean Water Act
                jurisdiction. In other words, discharges into those upstream waters
                remain subject to Clean Water Act requirements and thus may require a
                section 402 permit.\51\ The agencies request comment on whether to add
                language to the regulatory text of the waste treatment system exclusion
                clarifying these aspects of the exclusion.
                ---------------------------------------------------------------------------
                 \51\ See, e.g., Memorandum of Non-Concurrence with
                Jurisdictional Determinations POA-1992-574 & POA-1992-574-Z (October
                25, 2007), available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll5/id/1454 (``EPA and the Corps agree
                that the agencies' designation of a portion of waters of the U.S. as
                part of a waste treatment system does not itself alter CWA
                jurisdiction over any waters remaining upstream of such system.'').
                ---------------------------------------------------------------------------
                9. Other Definitions
                 The proposed rule contains a number of defined terms unchanged from
                the 1986 regulations. Some of the terms appeared only in the Corps'
                regulations, but in the 2019 Rule and the NWPR, the agencies included
                these definitions in both agencies' regulations. The agencies are not
                proposing to amend the definitions of ``wetland,'' ``high tide line,''
                ``ordinary high water mark,'' and ``tidal water'' from the 1986
                regulations, but to provide additional clarity and consistency in
                comparison to the 1986 regulations, the proposed rule would include all
                the defined terms in EPA's regulations, where such definitions are not
                already contained. Only the definition of the term ``adjacent'' was
                amended in the NWPR; the agencies are proposing to define the term
                unchanged from the 1986 regulations. This section briefly describes the
                definitions and their history and implementation. See section V.D of
                this preamble for further discussion on implementation.
                a. Wetlands
                 The proposed rule makes no changes to the definition of
                ``wetlands'' contained in the NWPR, which made no changes to the 1986
                regulations and defined ``wetlands'' as ``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.'' The agencies are not proposing to amend this
                definition.
                b. Adjacent
                 The proposed rule defines the term ``adjacent'' with no changes
                from the 1986 regulations as ``bordering, contiguous, or neighboring.
                Wetlands separated from other `waters of the United States' by man-made
                dikes or barriers, natural river berms, beach dunes and the like are
                `adjacent wetlands.' '' This is a longstanding and familiar definition
                that is supported by Supreme Court case law and science. See, e.g.,
                Riverside Bayview, 474 U.S. 121, 134 (`` . . . the Corps' ecological
                judgment about the relationship between waters and their adjacent
                wetlands provides an adequate basis for a legal judgment that adjacent
                wetlands may be defined as waters under the Act.''). The Supreme Court
                has noted that adjacent wetlands under this definition are not limited
                to only those that exist as a result of ``flooding or permeation by
                water having its source in adjacent bodies of open water,'' and that
                wetlands may affect the water quality in adjacent waters even when
                those waters do not actually inundate the wetlands. Id. at 134-35. As
                discussed in section V.C.7 of this preamble and consistent with the
                pre-2015 regulatory regime, to be jurisdictional under the adjacent
                wetlands provision of the proposed rule, wetlands must meet this
                definition of adjacent and either be adjacent to a traditional
                navigable water, interstate water, or territorial sea or otherwise fall
                within the adjacent wetlands provision and meet either the relatively
                permanent standard or the significant nexus standard. See section V.D
                of this preamble for further discussion on implementation.
                 The NWPR substantially narrowed the definition of ``adjacent''
                based primarily on the Rapanos plurality standard. The NWPR interprets
                ``adjacent wetlands'' to be those wetlands that abut jurisdictional
                waters and those non-abutting wetlands that are (1) ``inundated by
                flooding'' from a jurisdictional water in a typical year, (2)
                physically separated from a jurisdictional water only by certain
                natural features (e.g., a berm, bank, or dune), or (3) physically
                separated from a jurisdictional water by an artificial structure that
                ``allows for a direct hydrologic surface connection'' between the
                wetland and the jurisdictional water in a typical year. 85 FR 22251,
                April 21, 2020. Wetlands that do not have these types of connections to
                other jurisdictional waters are not jurisdictional under the NWPR. The
                NWPR's limits on the scope of protected wetlands to those that touch or
                demonstrate evidence of a regular surface water connection to other
                jurisdictional waters are inconsistent with the scientific information
                in the record demonstrating the effects of wetlands on the integrity of
                downstream waters when they have other types of surface connections,
                such as wetlands that overflow and flood jurisdictional waters or
                wetlands with less frequent surface water connections due to long-term
                drought; wetlands with shallow subsurface connections to other
                protected waters; or other wetlands proximate to jurisdictional waters.
                As discussed in section V.B.3.d of this preamble, within the first year
                of implementation of the NWPR, 70% of streams and wetlands evaluated
                were found to be non-jurisdictional, including 15,675 wetlands that did
                not meet the NWPR's revised adjacency criteria. The agencies anticipate
                that this increase in determinations of wetlands to be non-
                jurisdictional as compared to prior regulations could reduce the
                integrity of the nation's waters (see section V.B.3.d of this
                preamble), particularly in the absence of comparable state, tribal, or
                local regulations and associated efforts to avoid, minimize, or
                compensate for impacts to aquatic resources regulated under such
                programs.
                [[Page 69429]]
                 Proposing the longstanding definition of ``adjacent'' is consistent
                with Riverside Bayview and Justice Kennedy's opinion in Rapanos, as
                well as with scientific information indicating that wetlands meeting
                this definition provide important functions that contribute to the
                integrity of traditional navigable waters, interstate waters, and
                territorial seas. See section V.A of this preamble. The agencies are
                proposing to retain the provision of this definition from the 1986
                regulations that includes wetlands separated from other ``waters of the
                United States'' by man-made dikes or barriers, natural river berms,
                beach dunes and the like. The Supreme Court in Riverside Bayview
                deferred to the agencies' interpretation of the Clean Water Act to
                include adjacent wetlands. Riverside Bayview, 474 U.S. at 135 (``the
                Corps has concluded that wetlands adjacent to lakes, rivers, streams,
                and other bodies of water may function as integral parts of the aquatic
                environment even when the moisture creating the wetlands does not find
                its source in the adjacent bodies of water. . . . [W]e therefore
                conclude that a definition of `waters of the United States'
                encompassing all wetlands adjacent to other bodies of water over which
                the Corps has jurisdiction is a permissible interpretation of the
                Act''). Justice Kennedy stated: ``In many cases, moreover, filling in
                wetlands separated from another water by a berm can mean that
                floodwater, impurities, or runoff that would have been stored or
                contained in the wetlands will instead flow out to major waterways.
                With these concerns in mind, the Corps' definition of adjacency is a
                reasonable one, for it may be the absence of an interchange of waters
                prior to the dredge and fill activity that makes protection of the
                wetlands critical to the statutory scheme.'' Rapanos at 775.
                 Wetlands separated from other ``waters of the United States'' by
                man-made dikes or barriers, natural river berms, or beach dunes
                generally continue to have a hydrologic connection to downstream
                waters. This is because constructed dikes or barriers, natural river
                berms, beach dunes, and the like typically do not block all water flow.
                This hydrologic connection can occur via seepage or over-topping, where
                water from the nearby traditional navigable water, interstate water,
                the territorial seas, impoundment, or tributary periodically overtops
                the berm or other similar feature. Water can also overtop a natural
                berm or artificial dike and flow from the wetland to the water to which
                it is adjacent.
                 River berms, natural levees, and beach dunes are all examples of
                features that are formed by natural processes and do not isolate
                adjacent wetlands from the streams, lakes, or tidal waters that form
                them. River berms, natural levees, and the wetlands and waters behind
                them are part of the floodplain. Natural levees are discontinuous,
                which allows for a hydrologic connection to the stream or river via
                openings in the levees and thus the periodic mixing of river water and
                backwater. Beach dunes are formed by tidal or wave action, and the
                wetlands that establish behind them experience a fluctuating water
                table seasonally and yearly in synchrony with sea or lake level
                changes. The terms earthen dam, dike, berm, and levee are used to
                describe similar constructed structures whose primary purpose is to
                help control flood waters. Such man-made levees and similar structures
                also do not isolate adjacent wetlands.
                 In addition, adjacent wetlands separated from a jurisdictional
                water by a natural or man-made berm serve many of the same functions as
                other adjacent wetlands. There are also other important considerations,
                such as chemical and biological functions provided by the wetland. For
                instance, adjacent waters behind berms can still serve important water
                quality functions, serving to filter pollutants and sediment before
                they reach downstream waters. Wetlands behind berms, where the system
                is extensive, can help reduce the impacts of storm surges caused by
                hurricanes. Such adjacent wetlands, separated from waters by berms and
                the like, maintain ecological connection with those waters. For
                example, wetlands behind natural and artificial berms can provide
                important habitat for aquatic and semi-aquatic species that utilize
                both the wetlands and the nearby water, including for basic food,
                shelter, and reproductive requirements. Though a berm may reduce
                habitat functional value and may prevent some species from moving back
                and forth from the wetland to the nearby jurisdictional water, many
                species remain able to utilize both habitats despite the presence of
                such a berm, and in some cases, the natural or artificial barrier can
                serve the purpose of providing extra refuge from predators or for
                rearing young or other life cycle needs.
                 Thus, the longstanding definition of ``adjacent'' reasonably
                advances the objective of the Act. To be jurisdictional under the
                proposed rule, however, wetlands must meet this definition of adjacent
                and either be adjacent to a traditional navigable water, interstate
                water, or territorial sea or otherwise fall within the adjacent
                wetlands provision and meet either the relatively permanent standard or
                the significant nexus standard.
                c. High Tide Line
                 The proposed rule makes no changes to the definition of ``high tide
                line'' contained in the NWPR, which made no changes to the 1986
                regulations and defines the term ``high tide line'' as ``the line of
                intersection of the land with the water's surface at the maximum height
                reached by a rising tide. The high tide line may be determined, in the
                absence of actual data, by a line of oil or scum along shore objects, a
                more or less continuous deposit of fine shell or debris on the
                foreshore or berm, other physical markings or characteristics,
                vegetation lines, tidal gages, or other suitable means that delineate
                the general height reached by a rising tide. The line encompasses
                spring high tides and other high tides that occur with periodic
                frequency, but does not include storm surges in which there is a
                departure from the normal or predicted reach of the tide due to the
                piling up of water against a coast by strong winds such as those
                accompanying a hurricane or other intense storm.'' The agencies are not
                proposing to amend this definition. This definition has been in place
                since 1977 (see 42 FR 37144, July 19, 1977; and 33 CFR 323.3(c)
                (1978)), and like the definitions discussed above, is a well-
                established definition that is familiar to regulators, environmental
                consultants, and the scientific community. This term defines the
                landward limits of jurisdiction in tidal waters when there are no
                adjacent non-tidal ``waters of the United States.'' 51 FR 41206, 41251
                (November 13, 1986).
                d. Ordinary High Water Mark
                 The proposed rule makes no changes to the definition of ``ordinary
                high water mark'' (``OHWM'') contained in the NWPR, which made no
                changes to the 1986 regulations and defines OHWM as ``that line on the
                shore established by the fluctuations of water and indicated by
                physical characteristics such as clear, natural line impressed on the
                bank, shelving, changes in the character of soil, destruction of
                terrestrial vegetation, the presence of litter and debris, or other
                appropriate means that consider the characteristics of the surrounding
                areas.'' This term, unchanged since 1977, see 41 FR 37144 (July 19,
                1977) and 33 CFR 323.3(c) (1978), defines the lateral limits of
                jurisdiction in non-tidal waters, provided the limits of jurisdiction
                are not extended by adjacent wetlands. When adjacent wetlands are
                present, Clean Water Act jurisdiction extends beyond the OHWM
                [[Page 69430]]
                to the limits of the adjacent wetlands. Id.; Regulatory Guidance Letter
                (RGL) 05-05 (December 7, 2005) at 1. The agencies are not proposing to
                amend this definition. Establishing the presence of a non-tidal
                traditional navigable water's OHWM can be informed by remote sensing
                and mapping information.
                e. Tidal Water
                 The proposed rule makes no changes to the definition of ``tidal
                water'' contained in the NWPR, which made no changes to the 1986
                regulations, and defines the term ``tidal water'' as ``those waters
                that rise and fall in a predictable and measurable rhythm or cycle due
                to the gravitational pulls of the moon and sun. Tidal waters end where
                the rise and fall of the water surface can no longer be practically
                measured in a predictable rhythm due to masking by hydrologic, wind, or
                other effects.'' Although the term ``tidal waters'' was referenced
                throughout the Corps' 1977 regulations, including the preamble (e.g.,
                see 42 FR 37123, 37128, 37132, 37144, 37161, July 19, 1977), it was not
                defined in regulations until 1986. As explained in the preamble to the
                1986 regulations, this definition is consistent with the way the Corps
                has traditionally interpreted the term. 51 FR 41217, 41218 (November
                13,1986). The agencies are not proposing to amend this definition.
                10. Significantly Affect
                 The proposed rule defines the term ``significantly affect'' for
                purposes of determining whether a water meets the significant nexus
                standard to mean ``more than speculative or insubstantial effects on
                the chemical, physical, or biological integrity of'' a traditional
                navigable water, interstate water, or the territorial seas. Waters,
                including wetlands, would be evaluated either alone, or in combination
                with other similarly situated waters in the region,\52\ based on the
                functions the evaluated waters perform. The proposal also identifies
                specific ``factors'' that will be considered when assessing whether the
                ``functions'' provided by the water, alone or in combination, are more
                than speculative or insubstantial. The factors include readily
                understood criteria (e.g., distance, hydrologic metrics, and
                climatological metrics) that influence the types and strength of
                chemical, physical, or biological connections and associated effects on
                those downstream foundational waters. The functions can include
                measurable indicators (e.g., nutrient recycling, runoff storage) that
                are tied to the chemical, physical, and biological integrity of
                foundational waters. The definition of ``significantly affect'' is
                derived from the objective of the Clean Water Act, and is informed by
                and consistent with Supreme Court case law. It is also informed by the
                agencies' technical and scientific judgment and supported by the best
                available science regarding what waters must be protected to achieve
                the Clean Water Act's objective. The proposed definition recognizes
                that not all waters have the requisite connection to foundational
                waters sufficient to be determined jurisdictional.
                ---------------------------------------------------------------------------
                 \52\ For example, under the Rapanos Guidance, the agencies
                consider the flow and functions of the reach of a tributary that is
                the same stream order (i.e., from the point of confluence, where two
                lower order streams meet to form the tributary, downstream to the
                point such tributary enters a higher order stream) together with the
                functions performed by all the wetlands adjacent to that tributary
                in evaluating whether a significant nexus is present. Rapanos
                Guidance at 10. The agencies are taking comment on other approaches
                to ``similarly situated'' and ``in the region'' in section
                V.D.2.b.ii of this preamble.
                ---------------------------------------------------------------------------
                 The significant nexus standard that would be established by the
                proposed rule is carefully constructed to fall within the bounds of the
                Clean Water Act. First, the standard is limited to consideration of
                effects on downstream traditional navigable waters, interstate waters,
                and the territorial seas. Second, the standard is limited to effects
                only on the three statutorily identified aspects of those foundational
                waters: Chemical, physical, or biological integrity. Third, the
                standard cannot be met by merely speculative or insubstantial effects
                on those aspects of those foundational waters. Thus, the agencies must
                assess a particular water and determine whether, based on the factual
                record, relevant scientific data and information, and available tools,
                the water, alone or combination, has a more than speculative or
                insubstantial effect on the chemical, physical, or biological integrity
                of a specific foundational water.
                 This section explains the proposed definition and its consistency
                with the Rapanos Guidance, then explains how the proposed definition is
                consistent with the best available science and case law, and, finally,
                provides examples of functions that are not relevant to the significant
                nexus standard and waters that have not met the significant nexus
                standard under the pre-2015 regulatory regime.
                 The proposed definition is consistent with the pre-2015 regulatory
                regime. Under the Rapanos Guidance, the agencies evaluate whether
                waters ``are likely to have an effect that is more than speculative or
                insubstantial on the chemical, physical, and biological integrity of a
                traditional navigable water.'' Rapanos Guidance at 11.
                 In evaluating a water individually or in combination with other
                similarly situated waters for the presence of a significant nexus to a
                traditional navigable water, interstate water, or the territorial seas,
                the agencies consider factors that influence the types and strength of
                the chemical, physical, or biological connections and associated
                effects on those downstream waters. The agencies are proposing to
                include in the definition of ``significantly affect'' the factors to be
                considered in assessing the strength of the effects: (1) The distance
                from a jurisdictional water, (2) the distance from the downstream
                traditional navigable water, interstate water, or territorial sea, (3)
                hydrologic factors, including subsurface flow, (4) the size, density,
                and/or number of waters that have been determined to be similarly
                situated (and thus can be evaluated in combination), and (5)
                climatological variables such as temperature, rainfall, and snowpack.
                The agencies are seeking comment on this list of factors and whether
                there are other factors that influence the types and strength of the
                chemical, physical, or biological connections and associated effects on
                those downstream waters the agencies should consider.
                 These factors influence the strength of the connections and
                associated effects that streams, wetlands, and open waters have on the
                chemical, physical, and biological integrity of traditional navigable
                waters, interstate waters, and territorial seas and are not the
                functions themselves that the agencies might consider as part of a
                significant nexus standard. These factors also cannot be considered in
                isolation, but rather must be considered together and in the context of
                the case-specific analysis. For example, the likelihood of a connection
                with associated significant effects is generally greater with
                increasing number and size of the aquatic resource or resources being
                considered and decreasing distance from the identified foundational
                water as well as with increased density of the waters that can be
                considered in combination as similarly situated waters. However, the
                agencies also recognize that in watersheds with fewer aquatic
                resources, even a small number or low density of similarly situated
                waters can have disproportionate effects on downstream foundational
                waters. Hydrologic factors include volume (or magnitude), duration,
                timing, rate, and frequency of flow, size of the watershed or
                subwatershed, and surface and shallow subsurface hydrologic
                connections. The presence of a surface
                [[Page 69431]]
                or shallow subsurface hydrologic connection, as well as increased
                frequency, volume, or duration of such connections, can increase the
                chemical, physical (i.e., hydrologic), or biological impact that a
                water has on downstream foundational waters. In other situations,
                streams with low duration but a high volume of flow can significantly
                affect downstream foundational waters by transporting large volumes of
                water, sediment, and woody debris that help maintain the integrity of
                those larger downstream waters. The lack of hydrologic connections can
                also contribute to the strength of effects for certain functions such
                as floodwater attenuation or the retention and transformation of
                pollutants. Climatological factors like temperature, rainfall, and
                snowpack in a given region can influence the agencies' consideration of
                the effects of subject waters on downstream foundational waters by
                providing information about expected hydrology and the expected
                seasonality of connections and associated effects. The agencies are
                seeking comment on whether these factors are sufficiently clear or if
                further explanation or examples would be useful.
                 The agencies are also taking comment on whether it would be useful
                to add to the definition of ``significantly affect'' a specific list of
                functions of upstream waters to assess when making a significant nexus
                determination. The Rapanos Guidance identified some relevant functions
                upstream waters can provide including temperature regulation, sediment
                trapping and transport, nutrient recycling, pollutant trapping,
                transformation, filtering and transport, retention and attenuation of
                floodwaters and runoff, contribution of flow, provision of habitat for
                aquatic species that also live in foundational waters (e.g., for
                refuge, feeding, nesting, spawning, or rearing young), and provision
                and export of food resources for aquatic species located in
                foundational waters. Evaluation of such functions is consistent with
                the agencies' implementation of the pre-2015 regulatory regime. See
                Rapanos Guidance at 8, 9. Under the pre-2015 regulatory regime, a water
                did not need to perform all of the listed functions. See U.S. Army
                Corps of Engineers Jurisdictional Determination Form Instructional
                Guidebook. If a water, either alone or in combination with similarly
                situated waters, performs one function, and that function has a more
                than speculative or insubstantial impact on the integrity of a
                traditional navigable water, interstate water, or the territorial seas,
                that water would have a significant nexus.
                 These functions identified in the Rapanos Guidance that can be
                provided by tributaries, wetlands, and open waters are keyed to the
                chemical, physical, and biological integrity of traditional navigable
                waters, interstate waters, and the territorial seas. Water temperature
                is a critical factor governing the distribution and growth of aquatic
                life in downstream waters. Sediment storage and export via streams to
                downstream waters is important for maintaining the physical river
                network, including the formation of channel features. Nutrient
                recycling results in the uptake and transformation of large quantities
                of nitrogen and other nutrients that otherwise would be transported
                directly downstream, thereby decreasing impairments of downstream
                waters. Streams, wetlands, and open waters improve water quality
                through the assimilation and sequestration of pollutants, including
                chemical contaminants such as pesticides and metals that can degrade
                downstream water integrity. Small streams and wetlands are particularly
                effective at retaining and attenuating floodwaters. This function can
                reduce flood peaks downstream and can also maintain downstream river
                baseflows. Streams, wetlands, and open waters are the dominant sources
                of water in most rivers. Streams, wetlands, and open waters supply
                downstream waters with organic matter which supports biological
                activity throughout the river network and provide life-cycle dependent
                aquatic habitat for species located in foundational waters.
                 Consistent with the pre-2015 regulatory regime, the agencies are
                also proposing that a water may be determined to be a ``water of the
                United States'' when it ``significantly affects'' any one form of
                chemical, physical, or biological integrity of a downstream traditional
                navigable water, interstate water, or the territorial seas. Congress
                intended the Clean Water Act to ``restore and maintain'' all three
                forms of ``integrity,'' section 101(a), so if any one is compromised
                then that is contrary to the statute's stated objective. It would
                contravene the plain language of the statute and subvert the objective
                if the Clean Water Act only protected waters upon a showing that they
                had effects on every attribute of the integrity of a traditional
                navigable water, interstate water, or the territorial sea. As the
                agencies stated in the Rapanos Guidance: ``Consistent with Justice
                Kennedy's instruction, EPA and the Corps will apply the significant
                nexus standard in a manner that restores and maintains any of these
                three attributes of traditional navigable waters.'' Rapanos Guidance at
                10, n.35 and surrounding text.
                 The proposed rule's definition of ``significantly affect'' also is
                consistent with the conclusions of the Science Report. See Technical
                Support Document section IV.E. The Science Report concluded that
                watersheds are integrated at multiple spatial and temporal scales by
                flows of surface water and ground water, transport and transformation
                of physical and chemical materials, and movements of organisms.
                Further, the Science Report stated, although all parts of a watershed
                are connected to some degree--by the hydrologic cycle or dispersal of
                organisms, for example--the degree and downstream effects of those
                connections vary spatially and temporally, and are determined by
                characteristics of the physical, chemical, and biological environments
                and by human activities. Those spatial and temporal variations are
                reflected in the agencies' proposed requirement that ``significantly
                affect'' means more than speculative or insubstantial, in the functions
                the agencies evaluate, and in the factors they use to evaluate those
                functions. The proposed rule's provision for waters to be assessed
                either alone, or in combination with other similarly situated waters in
                the region is consistent with the Science Report, which gave as an
                example that the amount of water or biomass contributed by a specific
                ephemeral stream in a given year might be small, but the aggregate
                contribution of that stream over multiple years, or by all ephemeral
                streams draining that watershed in a given year or over multiple years,
                can have substantial consequences on the integrity of the downstream
                waters. Similarly, the downstream effect of a single event, such as
                pollutant discharge into a single stream or wetland, might be
                negligible but the cumulative effect of multiple discharges could
                degrade the integrity of downstream waters. The agencies are seeking
                comment on how to implement this aspect of the proposed rule in section
                V.D.2.b of this preamble.
                 The agencies' definition of the term ``significantly affect'' in
                the proposed rule is also informed by and consistent with Supreme Court
                case law. The definition reflects that not all waters have a requisite
                connection to foundational waters sufficient to be determined
                jurisdictional. Under the significant nexus standard, to be
                jurisdictional, waters, alone or in combination with other similarly
                situated waters in the region, must
                [[Page 69432]]
                significantly affect the chemical, physical, or biological integrity of
                a downstream traditional navigable water, interstate water, or
                territorial sea, and significantly affect means more than ``speculative
                or insubstantial.'' Rapanos, at 780. The agencies propose to define
                ``significantly affect'' in precisely those terms.
                 The facts in the cases before the justices further inform the scope
                of the proposed definition. Justice Kennedy was clear that ``[m]uch the
                same evidence should permit the establishment of a significant nexus
                with navigable-in-fact waters, particularly if supplemented by further
                evidence about the significance of the tributaries to which the
                wetlands are connected.'' Id. at 784. The agencies recognize that
                ``more than speculative or insubstantial'' is not a bright line
                definition, but as the Supreme Court has recently recognized in Maui,
                the scope of Clean Water Act jurisdiction does not always lend itself
                to bright lines: ``In sum, we recognize that a more absolute position .
                . . may be easier to administer. But, as we have said, those positions
                have consequences that are inconsistent with major congressional
                objectives, as revealed by the statute's language, structure, and
                purposes.'' Maui, 140 S Ct. at 1477. Because of the factual nature of
                the connectivity inquiry, any standard will require some case-specific
                factual determinations. The NWPR acknowledged that ``[a]s to simplicity
                and clarity, the agencies acknowledge that field work may frequently be
                necessary to verify whether a feature is a water of the United
                States.'' 85 FR 22270, April 21, 2020. But, like the Court in Maui, the
                agencies have proposed factors to be used in assessing the strength of
                the effects on downstream foundational waters and have identified the
                functions they will consider in making significant nexus determinations
                under the proposed rule. This approach is consistent with major
                congressional objectives, as revealed by the statute's language,
                structure, and purposes.\53\
                ---------------------------------------------------------------------------
                 \53\ Through rulemaking the agencies could make some categorical
                jurisdictional determination based on standards and factors that are
                consistent with the Act's objective. See Riverside Bayview at 135,
                n.9 (``If it is reasonable for the Corps to conclude that in the
                majority of cases, adjacent wetlands have significant effects on
                water quality and the aquatic ecosystem, its definition can
                stand.''); see also Rapanos at 780-81 (Kennedy, J.) (``Through
                regulations or adjudication, the Corps may choose to identify
                categories of tributaries 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.'').
                ---------------------------------------------------------------------------
                 It is also important to note that the agencies' significant nexus
                standard in the proposed rule is carefully tailored so that only
                particular types of functions provided by upstream waters can be
                considered. Wetlands, streams, and open waters are well-known to
                provide a wide variety of functions that translate into ecosystem
                services. A significant nexus analysis, however, is limited to an
                assessment of only those functions that have a nexus to the chemical,
                physical, or biological integrity of traditional navigable waters,
                interstate waters, or the territorial seas. Therefore, there are some
                very important functions provided by wetlands, tributaries, and ``other
                waters'' that will not be considered by the agencies when making
                jurisdictional decisions under the proposed rule because they do not
                have a sufficient nexus to downstream waters.
                 For example, for purposes of a jurisdictional analysis under the
                significant nexus standard, the agencies will not be taking into
                account the carbon sequestration benefits that aquatic resources like
                wetlands provide. Provision of habitat for non-aquatic species, such as
                migratory birds, and endemic aquatic species would not be considered as
                part of a significant analysis under the proposed rule.\54\
                Furthermore, the agencies would not consider soil fertility in
                terrestrial systems, which is enhanced by processes in stream and
                wetland soils and non-floodplain wetlands that accumulate sediments,
                prevent or reduce soil erosion, and retain water on the landscape,
                benefiting soil quality and productivity in uplands. There are also a
                wide variety of functions that streams, wetlands, and open waters
                provide that translate into ecosystem services that benefit society
                that would not be considered in a significant nexus analysis under the
                proposed rule. These include recreation (e.g., fishing, hunting,
                boating, and birdwatching), production of fuel, forage, and fibers,
                extraction of materials (e.g., biofuels, food, such as shellfish,
                vegetables, seeds, nuts, rice), plants for clothes and other materials,
                and medical compounds from wetland and aquatic plants or animals. While
                these ecosystem services can contribute to the economy, they are not
                relevant to a significant nexus analysis that the agencies would
                conduct under the proposed rule.
                ---------------------------------------------------------------------------
                 \54\ As the agencies have discussed, consideration of biological
                functions such as provision of habitat is relevant for purposes of
                significant nexus determinations under the proposed rule only to the
                extent that the functions provided by tributaries, adjacent
                wetlands, and ``other waters'' significantly affect the biological
                integrity of a downstream foundational water.
                ---------------------------------------------------------------------------
                 The agencies have more than a decade of experience implementing the
                significant nexus standard by making determinations of whether a water
                alone or in combination with similarly situated waters has a more than
                speculative or insubstantial effect. In their experience many waters
                under the proposed rule will not have a significant nexus to downstream
                foundational waters, and thus will not be jurisdictional under the Act,
                and the agencies under current practice routinely conclude that there
                is no significant nexus. The following are examples of waters that the
                agencies found to not have a significant nexus and determined to be
                non-jurisdictional under the pre-2015 regulatory regime. The agencies
                are citing these samples to provide an indication of waters that would
                likely not be jurisdictional under the proposed rule, though they
                recognize that the significant nexus determination is case-specific.
                 Examples of waters that were determined not to have a significant
                nexus to downstream foundational waters and that were non-
                jurisdictional under the pre-2015 regulatory regime, and which
                therefore would likely not be jurisdictional under the proposed rule,
                are a linear stream in Ohio, hundreds of feet long, which is miles from
                a traditional navigable water and does not provide any significant
                functions for that water; an ephemeral stream in Ohio in an
                agricultural field, which loses bed and bank and flows into an upland
                swale; and ditches in California that were created from uplands, drain
                only uplands, and that do not carry a relatively permanent flow of
                water.
                 Examples of wetlands that have been determined not to meet the
                significant nexus standard and therefore to be non-jurisdictional under
                the pre-2015 regulatory regime and would likely not be jurisdictional
                under the proposed rule include wetlands or open waters that drain into
                upland areas, such as emergent wetlands in Idaho that drain into upland
                swales that terminate in a closed basin upland area; wetlands in
                Wisconsin surrounded by uplands that do not exchange surface water or
                have ecological connections with the nearest tributary; wetlands in
                Ohio surrounded by upland that have no connections to any apparent
                surface water channel or to a jurisdictional water; and a non-navigable
                lake in Oregon contained within a valley and that lacks surface
                hydrologic connections to the river network. Other wetlands determined
                not meet the significant nexus standard include an emergent wetland in
                Alaska
                [[Page 69433]]
                surrounded by development that severed any hydrologic connections
                between the wetland and a nearby wetland complex and lake; wetlands in
                Washington separated by potential jurisdictional waters by thousands of
                feet of well-drained soils as well as impervious surfaces; a large
                forested wetland in Washington separated by the nearest jurisdictional
                waters by residential and commercial developments on a topography that
                would preclude flows into these waters and with no identified
                ecological connections; a wetland in Oregon surrounded by a concrete
                and cinder block wall, preventing any flows into downstream waters; and
                a wetland in Arkansas separated from other wetlands and surrounded by
                uplands.
                 While in most of these examples, the tributary, wetland, or lake
                may well have had some effect on traditional navigable waters,
                interstate waters, or the territorial seas, the agencies concluded that
                those effects were not significant and so concluded that jurisdiction
                did not lie under the Clean Water Act. See implementation section V.D
                of this preamble for more information on significant nexus
                determinations.
                D. Implementation of Proposed Rule
                 The agencies are proposing to return to the longstanding definition
                of ``waters of the United States'' that two other Administrations have
                codified over the years, updated to reflect consideration of the
                intervening Supreme Court decisions. This section first discusses
                features over which the agencies generally did not assert jurisdiction
                under the preambles, guidance, and practice of the pre-2015 regulatory
                regime. The agencies intend to continue generally not asserting
                jurisdiction over such features. Then the agencies explain the Rapanos
                Guidance and how they have determined jurisdiction under the two
                Rapanos standards for various categories of waters under the pre-2015
                regulatory regime and solicit comment on potential alternative
                approaches for applying the Rapanos standards. The agencies then
                discuss the implementation tools and resources available for making
                such determinations. The agencies welcome comment on all of these
                topics, including the availability and efficacy of all of the tools and
                resources discussed. The agencies intend to issue an updated ``Approved
                Jurisdictional Determination'' form and instruction manual upon
                promulgating a final rule to aid the public and field staff in
                determining which waters are ``waters of the United States'' under the
                final rule. The agencies may provide additional guidance in the final
                rule based on public input received on this proposal.
                1. Generally Not Considered ``waters of the United States''
                 Under the pre-2015 regulatory regime, the waters described below
                were generally not considered ``waters of the United States'' even
                though they were not explicitly excluded by regulation. The agencies
                intend to continue this longstanding approach and are soliciting
                comment on this approach for the proposed rule. The preamble to the
                1986 regulations states that the agencies ``generally do not consider
                [these] waters to be `Waters of the United States.' '' 51 FR 41217. The
                preamble further stated that ``the Corps reserves the right on a case-
                by-case basis to determine that a particular waterbody within these
                categories of waters is a water of the United States. EPA also has the
                right to determine on a case-by-case basis if any of these waters are
                `waters of the United States.' '' Id. In practice, the agencies have
                not generally asserted jurisdiction over such waters and would continue
                to implement the proposed rule consistent with this practice.
                 Even when not themselves considered jurisdictional waters subject
                to the Clean Water Act, the features described below (e.g., certain
                ditches, swales, gullies, erosional features) may either be relevant to
                a ``water of the United States'' jurisdictional analysis or otherwise
                be subject to the Clean Water Act. The features may still contribute to
                a surface hydrologic connection relevant for asserting jurisdiction
                (e.g., between an adjacent wetland and a jurisdictional water). Rapanos
                Guidance at 12. In addition, these waters may function as point sources
                (i.e., ``discernible, confined, and discrete conveyances''), such that
                discharges of pollutants to other waters through these features could
                require a Clean Water Act section 402 or 404 permit. Discharges to
                these waters may be subject to other Clean Water Act regulations (e.g.,
                Clean Water Act section 311). Id.
                a. Certain Ditches
                 Under the agencies' longstanding approach to determining which
                waters are ``waters of the United States,'' certain ditches are
                generally not considered ``waters of the United States.'' The preamble
                to the 1986 regulations explains that ``[n]on-tidal drainage and
                irrigation ditches excavated on dry land'' are generally not considered
                ``waters of the United States.'' 51 FR 41217. The agencies shifted this
                approach slightly in the Rapanos Guidance and explained that ``ditches
                (including roadside ditches) excavated wholly in and draining only
                uplands and that do not carry a relatively permanent flow of water are
                generally not waters of the United States.'' Rapanos Guidance at 11-12.
                The agencies explained that these features are generally not considered
                ``waters of the United States'' ``because they are not tributaries or
                they do not have a significant nexus to downstream traditional
                navigable waters.'' Id.
                 The agencies intend to continue implementing the approach to
                ditches described in the Rapanos Guidance. This approach is more
                consistent with the relatively permanent standard than the approach in
                the preamble to the 1986 regulations. Consistent with previous
                practice, ditches constructed wholly in uplands and draining only
                uplands with ephemeral flow would generally not be considered ``waters
                of the United States.''
                 Also consistent with previous practice, the agencies would
                typically assess a ditch's jurisdictional status based on whether it
                could be considered a tributary (and, consistent with previous
                practice, would not assess whether the ditch was jurisdictional under
                the ``other waters'' provision). The implementation section below
                includes discussion on the application of relevant reach under the
                Rapanos Guidance, and the agencies solicit comment on potential
                alternative approaches (see section V.D.2.b.ii.1.b of this preamble),
                such as whether relevant reaches can be distinguished based on a change
                from relatively permanent flow to non-relatively permanent flow. The
                agencies acknowledge that for ditches in particular there may be
                scenarios that make identification of relevant reach especially
                challenging and encourage stakeholders to identify and discuss these
                situations in their comments on relevant reach. The agencies
                specifically request comment regarding whether the interpretation of
                relevant reach for ditches should consider any particular factors for
                situations where ditches are tidal, are treated as tributaries, or
                contain wetlands.
                 In some situations, ditches with wetland characteristics have been
                considered jurisdictional as adjacent wetlands. In most cases, such
                ditches have been constructed in adjacent wetlands and would be
                considered part of that larger adjacent wetland. However, consistent
                with previous practice, wetlands that develop entirely within the
                confines of a ditch that was excavated in and wholly draining only
                uplands that does not carry a relatively permanent flow would be
                considered
                [[Page 69434]]
                part of that ditch and generally would not be considered ``waters of
                the United States.''
                 Where a ditch is jurisdictional, the agencies have historically
                taken the position that the ditch can be both a ``water of the United
                States'' and a point source and are proposing to reinstate this
                position. For example, in 1975, the General Counsel of EPA issued an
                opinion interpreting the Clean Water Act: ``it should be noted that
                what is prohibited by section 301 is `any addition of any pollutant to
                navigable waters from any point source.' It is therefore my opinion
                that, even should the finder of fact determine that any given
                irrigation ditch is a navigable water, it would still be permittable as
                a point source where it discharges into another navigable water body,
                provided that the other point source criteria are also present.'' In re
                Riverside Irrigation District, 1975 WL 23864 at *4 (emphasis in
                original). The opinion stated that ``to define the waters here at issue
                as navigable waters and use that as a basis for exempting them from the
                permit requirement appears to fly directly in the face of clear
                legislative intent to the contrary.'' Id. Further, in Rapanos, Justice
                Kennedy and the dissent rejected the conclusion that because the word
                ``ditch'' was in the definition of ``point source'' a ditch could never
                be a water of the United States: ``certain water bodies could
                conceivably constitute both a point source and a water.'' 547 U.S. at
                772 (Kennedy, J., concurring); see also id. at 802 (Stevens, J.,
                dissenting) (``The first provision relied on by the plurality--the
                definition of ``point source'' in 33 U.S.C. [section] 1362(14)--has no
                conceivable bearing on whether permanent tributaries should be treated
                differently from intermittent ones, since `pipe[s], ditch[es],
                channel[s], tunnel[s], conduit[s], [and] well[s]' can all hold water
                permanently as well as intermittently.'').
                 The agencies recognize that this position is different than the
                position in the NWPR, which stated that a ditch is either a water of
                the United States or a point source. 85 FR 22297, April 21, 2020. The
                NWPR justified this position by noting that the Clean Water Act defines
                ``point sources'' to include ditches and that the plurality opinion in
                Rapanos stated that ``[t]he definitions thus conceive of `point
                sources' and `navigable waters' as separate and distinct categories.
                The definition of `discharge' would make little sense if the two
                categories were significantly overlapping.'' 547 U.S. at 735-36
                (Scalia, J., plurality), NWPR Response to Comments, section 6 at 12-13.
                The NWPR, however, did not address that even this statement in the
                plurality opinion in Rapanos acknowledges that there may be some
                overlap between point sources and ``waters of the United States'' as
                indicated by its finding that the two categories should not be
                ``significantly'' overlapping. Id. Moreover, there is no indication in
                the text of the Clean Water Act that ditches that meet that plain
                language definition of a point source cannot also be a ``water of the
                United States.'' The agencies therefore believe that their
                longstanding, historic view that a ditch can be both a point source and
                a water of the United States is the better interpretation.
                b. Certain Other Features
                 In addition to the ditches described above, the agencies have
                generally not asserted jurisdiction over certain other features under
                the pre-2015 regulatory regime and the agencies intend to continue the
                practice for these features. The preamble to the 1986 regulations
                explains that these other waters include: Artificially irrigated areas
                which would revert to upland if the irrigation ceased; artificial lakes
                or ponds created by excavating and/or diking dry land to collect and
                retain water and which are used exclusively for such purposes as stock
                watering, irrigation, settling basins, or rice growing; artificial
                reflecting or swimming pools or other small ornamental bodies of water
                created by excavating and/or diking dry land to retain water for
                primarily aesthetic reasons; and waterfilled depressions created in dry
                land incidental to construction activity and pits excavated in dry land
                for the purpose of obtaining fill, sand, or gravel unless and until the
                construction or excavation operation is abandoned and the resulting
                body of water meets the definition of ``waters of the United States.''
                51 FR 41217. In the Rapanos Guidance, the agencies added an additional
                category to this list, explaining that ``[s]wales or erosional features
                (e.g., gullies, small washes characterized by low volume, infrequent,
                or short duration flow) are generally not waters of the United
                States.'' Rapanos Guidance at 11-12. The agencies explained that these
                features are generally not ``waters of the United States'' ``because
                they are not tributaries or they do not have a significant nexus to
                downstream traditional navigable waters.'' Id.
                 Swales and gullies are generally not jurisdictional, and these
                features differ from ephemeral streams because they lack indicators of
                an OHWM, whereas ephemeral streams typically have at least one
                indicator of an OHWM. Ephemeral streams are jurisdictional where they
                are tributaries and have a significant nexus to downstream waters.
                Colloquial terminology may differ across the country; for example, some
                streams in the arid West are known as ``gullies'' but are in fact
                ephemeral streams because they have at least one indicator of an OHWM.
                2. Determining Jurisdiction Under the Relatively Permanent Standard and
                the Significant Nexus Standard
                 In this section, the agencies explain how they have determined
                jurisdiction under the relatively permanent standard and significant
                nexus standard for various categories of waters under the pre-2015
                regulatory regime. The agencies describe how each standard has been
                implemented consistent with the Rapanos Guidance, SWANCC Guidance, and
                other aspects of longstanding practice where not addressed explicitly
                by the guidances. The agencies then solicit comment on implementing the
                standards consistent with the pre-2015 regulatory regime as well as
                potential alternative approaches for applying the relatively permanent
                and significant nexus standards. Additionally, the agencies solicit
                comment on whether the implementation approaches adequately account for
                expected changes in climate, and whether alternative approaches to
                implementing the relatively permanent standard and significant nexus
                standard should be considered.
                a. ``Waters of the United States'' Under the Relatively Permanent
                Standard
                i. Approaches Under the Pre-2015 Regulatory Regime
                (1) Background
                 Under the relatively permanent standard, relatively permanent
                tributaries and adjacent wetlands that have a continuous surface
                connection to such tributaries are jurisdictional under the Clean Water
                Act as ``waters of the United States.'' Under the Rapanos Guidance, the
                agencies assert jurisdiction over tributaries as ``relatively
                permanent'' waters where the waters typically (e.g., except due to
                drought) flow year-round or have a continuous flow at least seasonally
                (e.g., typically three months). Rapanos Guidance at 6-7 (citing 126 S
                Ct. at 2221 n.5 (Justice Scalia, plurality opinion) (explaining that
                ``relatively permanent'' does not necessarily exclude waters ``that
                might dry up in extraordinary circumstances such as drought'' or
                ``seasonal rivers, which contain continuous flow during some months of
                the year but no flow during dry
                [[Page 69435]]
                months'')). The agencies also assert jurisdiction over adjacent
                wetlands that have a continuous surface connection to a relatively
                permanent, non-navigable tributary. Id. at 6-7.
                (2) Tributaries
                 Under the Rapanos Guidance, ``relatively permanent'' tributaries
                include perennial streams that typically flow year-round and
                intermittent streams that have continuous flow at least seasonally.
                However, ``relatively permanent'' tributaries do not include ephemeral
                streams that flow only in response to precipitation and intermittent
                streams which do not have continuous flow at least seasonally.
                Importantly, under the Rapanos Guidance, some intermittent streams are
                considered ``relatively permanent'' and some are not. Scientists,
                including agency staff, have used the terms ``perennial,''
                ``intermittent,'' and ``ephemeral'' for decades to characterize
                tributary flow classifications.
                 Under the Rapanos Guidance, a ``tributary'' includes ``the entire
                reach of the stream that is of the same order (i.e., from the point of
                confluence, where two lower order streams meet to form the tributary,
                downstream to the point such tributary enters a higher order stream).''
                Id. at 6, n. 24. The flow characteristics of a particular tributary
                generally are evaluated at the farthest downstream limit of such
                tributary (i.e., the point the tributary enters a higher order stream).
                Id. However, for purposes of determining whether the tributary is
                relatively permanent, where data indicate the flow regime at the
                downstream limit is not representative of the entire tributary (e.g.,
                where data indicate the tributary is relatively permanent at its
                downstream limit but not for the majority of its length, or vice
                versa), the flow regime that best characterizes the entire tributary is
                used. A primary factor in making this determination is the relative
                lengths of segments with differing flow regimes. Id. The agencies
                stated that it is reasonable to characterize the entire tributary in
                light of the Supreme Court's observation that the phrase ``navigable
                waters'' generally refers to ``rivers, streams, and other hydrographic
                features.'' Citing Rapanos at 734, quoting Riverside Bayview, 474 U.S.
                at 131. The entire reach of a stream is a reasonably identifiable
                hydrographic feature.
                (3) Wetlands
                 Under the pre-2015 regime, the agencies utilize the Rapanos
                Guidance to determine where adjacent wetlands have a continuous surface
                connection with a relatively permanent, non-navigable tributary. The
                Rapanos Guidance notes that these wetlands are a subset of the broader
                definition of ``adjacent'' wetlands. The plurality opinion indicates
                that ``continuous surface connection'' is a ``physical connection
                requirement.'' Rapanos Guidance at 6, citing Rapanos at 754.
                Accordingly, under the Rapanos Guidance, a continuous surface
                connection exists between a wetland and a relatively permanent, non-
                navigable tributary where the wetland directly abuts the tributary
                (e.g., they are not separated by uplands, a berm, dike, or similar
                feature). Rapanos Guidance at 7, citing Rapanos at 751, n. 13
                (referring to ``our physical-connection requirement''). A continuous
                surface connection does not require surface water to be continuously
                present between the wetland and the tributary. Rapanos Guidance at 7,
                n.28, citing 33 CFR 328.3(b) and 40 CFR 232.2 (defining wetlands as
                ``those areas that are inundated or saturated by surface or ground
                water at a frequency and duration sufficient to support a prevalence of
                vegetation typically adapted for life in saturated soil conditions'').
                 In some circumstances, the United States has determined that a
                continuous surface connection can include a physical connection such as
                a non-jurisdictional ditch that connects the adjacent wetland to the
                relatively permanent tributary. United States v. Cundiff, 555 F.3d at
                213 (holding wetlands were jurisdictional under the plurality where
                plaintiff created a continuous surface connection by digging ditches to
                enhance the acid mine drainage into the creeks and away from his
                wetlands; ``it does not make a difference whether the channel by which
                water flows from a wetland to a navigable-in-fact waterway or its
                tributary was manmade or formed naturally''). Generally, the agencies
                completed significant nexus analyses on adjacent wetlands with such
                connections.
                 The term ``adjacent'' has been defined in agency regulations since
                1986 to mean ``bordering, contiguous, or neighboring.'' Wetlands
                separated from other ``waters of the United States'' by man-made dikes
                or barriers, natural river berms, beach dunes and the like are
                ``adjacent wetlands'' (see section V.C.7 of this preamble). Under the
                Rapanos Guidance, the agencies consider wetlands ``adjacent'' if one of
                following three criteria is satisfied. First, there is an unbroken
                surface or shallow subsurface connection to jurisdictional waters and
                this hydrologic connection maybe intermittent. Second, they are
                physically separated from jurisdictional waters by man-made dikes or
                barriers, or natural breaks (e.g., river berms, beach dunes). Or third,
                their proximity to a jurisdictional water is reasonably close,
                supporting the science-based inference that such wetlands have an
                ecological interconnection with jurisdictional waters and therefore,
                will not generally require a case-specific demonstration of an ecologic
                interconnection. Rapanos Guidance at 5-6.
                 As stated above, under the Rapanos Guidance the agencies assert
                jurisdiction over wetlands that have a continuous surface connection
                with a relatively permanent, non-navigable tributary. These wetlands
                are a subset of adjacent wetlands previously discussed that must have a
                continuous surface connection with the tributary. This physical
                connection requires that the wetland not be separated from the
                relatively permanent, non-navigable tributary by uplands, a berm, dike,
                or other similar feature. Although a constant hydrologic connection is
                not required, there must be a continuous surface connection on the
                landscape for these wetlands to be jurisdictional under this standard.
                 It is important to note that under the pre-2015 regulatory regime,
                features such as uplands, a berm, dike, or similar feature that
                separate a wetland from a relatively permanent, non-navigable tributary
                may not be continuous. For example, an upland levee that separates a
                wetland from a relatively permanent, non-navigable tributary may have
                gaps along the length of the levee that provide for a connection
                between the wetlands and the tributary. In such cases under the pre-
                2015 regulatory regime, this type of connection would satisfy the
                physical connection requirement.
                ii. Other Potential Approaches To Implementing the Relatively Permanent
                Standard
                 The agencies are seeking comment on whether they should implement
                the relatively permanent standard in the proposed rule consistent with
                the pre-2015 regulatory regime described above and if so whether there
                are clarifications or other issues to be addressed. In addition, the
                agencies are seeking comment on other options for making jurisdictional
                determinations under the relatively permanent standard.
                (1) Tributaries
                 The Rapanos Guidance limits the scope of relatively permanent
                tributaries to perennial tributaries and certain
                [[Page 69436]]
                intermittent tributaries. The agencies could interpret relatively
                permanent waters more generally to include perennial tributaries and
                all intermittent tributaries. With such an interpretation, the agencies
                could use an approach to ``perennial,'' ``intermittent,'' and
                ``ephemeral'' as the NWPR did and could specify that the agencies
                generally intend to consider perennial and intermittent tributaries as
                relatively permanent waters in light of their characteristics and flow,
                but ephemeral tributaries would not be considered relatively permanent.
                Such an approach would not limit intermittent tributaries under the
                relatively permanent standard to only those that have continuous flow
                at least seasonally (e.g., typically three months). The agencies could
                clarify that intermittent streams under the relatively permanent
                standard may flow less than three months (e.g., streams that flow
                ``continuously during certain times of the year,'' similar to the
                language in the NWPR), as certain intermittent streams may flow for
                shorter periods of time but are still distinct from ``ephemeral''
                streams.
                 The Rapanos Guidance does not explicitly address whether
                intermittent flow must come from particular sources (e.g., groundwater,
                snowpack melt, effluent flow, or upstream contributions of flow) under
                the relatively permanent standard. The agencies solicit comment about
                whether the final rule should clarify the required sources of
                intermittent flow, and what those sources of flow should be. For
                instance, the NWPR clarified that intermittent flow must occur more
                than in direct response to precipitation, and the NWPR explained that
                could mean, for example, seasonally when the groundwater table is
                elevated or when snowpack melts. The NWPR differentiated between
                ephemeral flows driven by ``snowfall,'' and intermittent flows driven
                by ``snowpack melt,'' where snowpack was 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).'' Alternatively, the final rule could allow for regionally
                specific interpretations of intermittent flow sources to allow for
                flexible implementation of the rule.
                 This proposed rule does not provide specific definitions for
                tributary flow classifications, including the terms ``perennial,''
                ``intermittent,'' and ``ephemeral.'' The agencies are seeking comment
                on whether they should define these flow classifications in the final
                rule. Any specific definitions would depend in part on how the agencies
                describe intermittent tributaries under the relatively permanent
                standard in the final rule, including the scope of intermittent
                tributaries and any description of required sources of flow. For
                example, if the agencies interpret the relatively permanent standard to
                include all perennial and intermittent tributaries and decide to
                include groundwater and snowpack melt as appropriate sources of
                intermittent flow, the agencies could use the same definitions as the
                NWPR:
                 The term ``perennial'' means surface water flowing
                continuously year-round.
                 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).
                 The term ``ephemeral'' means surface water flowing or
                pooling only in direct response to precipitation (e.g., rain or snow
                fall).
                 Alternatively, the agencies could interpret the relatively
                permanent standard using modified definitions of these terms.
                (2) Wetlands
                 In some circumstances, the United States has concluded that a non-
                jurisdictional ditch or other such feature can serve as a physical
                connection that maintains a continuous surface connection between a
                wetland and a relatively permanent water. See United States v. Cundiff.
                The agencies seek comment on whether to provide guidance on when
                specific features (e.g., ditches, culverts, pipes, or swales) can serve
                as physical connections that can maintain a continuous surface
                connection between a wetland and a relatively permanent water.
                (3) Open Waters
                 The agencies do not discuss in the Rapanos Guidance the assessment
                of open waters such as lakes and ponds under the relatively permanent
                waters standard. As discussed above, the agencies' longstanding
                position, reflected in the U.S. Army Corps of Engineers Jurisdictional
                Determination Instructional Guidebook, is that tributaries for purposes
                of the definition of ``waters of the United States'' include lakes and
                ponds that flow directly or indirectly to downstream traditional
                navigable waters, interstate waters, or the territorial seas. See U.S.
                Army Corps of Engineers Jurisdictional Determination Form Instructional
                Guidebook, at 8, 9. In practice, the agencies have asserted
                jurisdiction over relatively permanent tributary lakes and ponds. The
                agencies are soliciting comment on whether they should explicitly
                explain this implementation approach in the final rule.
                 The agencies do not address the ``other waters'' category in the
                Rapanos Guidance with respect to either the relatively permanent
                standard or the significant nexus standard. The proposed rule adds both
                standards to the ``other waters'' category. The agencies are soliciting
                comment on whether they should take an approach to assessing
                jurisdiction over non-tributary open waters under the relatively
                permanent standard that is similar to the approach described in the
                Rapanos Guidance for assessing jurisdiction over adjacent wetlands with
                a continuous surface connection to relatively permanent waters. Under
                such an approach, the agencies would assert jurisdiction over
                relatively permanent open waters that have a continuous surface
                connection with a relatively permanent, non-navigable tributary. The
                agencies note that some such lakes and ponds are jurisdictional under
                the NWPR when they are inundated by flooding from a jurisdictional
                water in a typical year.
                b. ``Waters of the United States'' Under the Significant Nexus Standard
                ii. Approaches Under the Pre-2015 Regulatory Regime
                (1) Background
                 The significant nexus standard as clarified by Justice Kennedy's
                opinion in Rapanos is: ``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.''' Rapanos at 780. The agencies in the Rapanos Guidance use
                the significant nexus standard for determining jurisdiction over
                certain adjacent wetlands and tributaries. As discussed above, the
                proposed rule would add the significant nexus standard to the ``other
                waters,'' tributary, and adjacent wetland categories in the 1986
                regulations. In the Rapanos Guidance, the agencies explain: ``While
                Justice Kennedy's opinion discusses the significant nexus standard
                primarily in the context of wetlands adjacent to non-navigable
                tributaries, his opinion also addresses Clean Water Act jurisdiction
                over tributaries themselves. Justice Kennedy states that, based on the
                Supreme Court's decisions in Riverside Bayview
                [[Page 69437]]
                and SWANCC, `the connection between a non-navigable water or wetland
                may be so close, or potentially so close, that the Corps may deem the
                water or wetland a ``navigable water'' under the Act.''' Rapanos
                Guidance at 9, citing Rapanos at 767 (emphasis added in Rapanos
                Guidance).
                (2) Scope of Significant Nexus Analysis
                 In the Rapanos Guidance, the agencies assess tributaries and their
                adjacent wetlands together and state: ``In considering how to apply the
                significant nexus standard, the agencies have focused on the integral
                relationship between the ecological characteristics of tributaries and
                those of their adjacent wetlands, which determines in part their
                contribution to restoring and maintaining the chemical, physical and
                biological integrity of the Nation's traditional navigable waters. The
                ecological relationship between tributaries and their adjacent wetlands
                is well documented in the scientific literature and reflects their
                physical proximity as well as shared hydrological and biological
                characteristics. The flow parameters and ecological functions that
                Justice Kennedy describes as most relevant to an evaluation of
                significant nexus result from the ecological inter-relationship between
                tributaries and their adjacent wetlands.'' Rapanos Guidance at 9.
                 Under the Rapanos Guidance, when performing a significant nexus
                analysis, the first step is to determine the relevant reach of the
                tributary being assessed, even when the subject water may only include
                a wetland. Under the guidance, a tributary is the entire reach of the
                stream that is of the same order (i.e., from the point of confluence,
                where two lower order streams meet to form the tributary, downstream to
                the point such tributary enters a higher order stream). The guidance
                states that for purposes of demonstrating a connection to traditional
                navigable waters, it is appropriate and reasonable to assess the flow
                characteristics of the tributary at the point at which water is in fact
                being contributed to a higher order tributary or to a traditional
                navigable water. As discussed above, the agencies' longstanding
                position is that tributaries for purposes of the definition of ``waters
                of the United States'' include lakes and ponds that flow directly or
                indirectly to downstream traditional navigable waters, interstate
                waters, or the territorial seas. See ``U.S. Army Corps of Engineers
                Jurisdictional Determination Form Instructional Guidebook,'' at 8, 9.
                In practice, the agencies have asserted jurisdiction over tributary
                lakes and ponds that meet the significant nexus standard.
                 After establishing the relevant reach of the tributary, under the
                Rapanos Guidance the agencies then determine if the tributary has any
                adjacent wetlands. Where a tributary has no adjacent wetlands, the
                agencies consider the flow characteristics and functions of only the
                tributary itself in determining whether such tributary has a
                significant effect on the chemical, physical and biological integrity
                of downstream traditional navigable waters, interstate waters, or the
                territorial seas. Rapanos Guidance at 10. If the tributary has adjacent
                wetlands, the significant nexus evaluation needs to recognize the
                ecological relationship between tributaries and their adjacent
                wetlands, and their closely linked role in protecting the chemical,
                physical, and biological integrity of downstream traditional navigable
                waters. Id. at 10.
                 Under the Rapanos Guidance the agencies consider the flow and
                functions of the tributary together with the functions performed by all
                the wetlands adjacent to the tributary in evaluating whether a
                significant nexus is present. This approach reflects the agencies'
                interpretation in the Rapanos Guidance of Justice Kennedy's term
                ``similarly situated'' to include all wetlands adjacent to the same
                tributary. Under this approach, where it is determined that a tributary
                and its adjacent wetlands collectively have a significant nexus with
                traditional navigable waters, the tributary and all of its adjacent
                wetlands are jurisdictional. Id. at 10.
                 In addition, the Rapanos Guidance states that certain ephemeral
                waters in the arid West are distinguishable from the geographic
                features like non-jurisdictional swales and erosional features, where
                such ephemeral waters are tributaries and they have a significant nexus
                to downstream traditional navigable waters. For example, in some cases
                these ephemeral tributaries may serve as a transitional area between
                the upland environment and the traditional navigable waters. The
                guidance explains that during and following precipitation events,
                ephemeral tributaries collect and transport water and sometimes
                sediment from the upper reaches of the landscape downstream to the
                traditional navigable waters. These ephemeral tributaries may provide
                habitat for wildlife and aquatic organisms in downstream traditional
                navigable waters. These biological and physical processes may further
                support nutrient cycling, sediment retention and transport, pollutant
                trapping and filtration, and improvement of water quality, functions
                that may significantly affect the chemical, physical, and biological
                integrity of downstream traditional navigable waters. Id. at 12. In
                practice, the agencies have regulated some but not all ephemeral
                tributaries evaluated under the significant nexus standard under the
                pre-2015 regulatory regime.
                (3) Assessment of a Significant Nexus
                 To implement the Rapanos Guidance, the agencies instruct field
                staff evaluating the significant nexus of a tributary and its adjacent
                wetlands to evaluate all available hydrologic information (e.g., gage
                data, precipitation records, flood predictions, historic records of
                water flow, statistical data, personal observations/records, etc.) and
                physical indicators of flow including the presence and characteristics
                of a reliable OHWM when assessing significant nexus. Rapanos Guidance
                at 10. The use of relevant geographic water quality data in conjunction
                with site-specific data produced from improved field sampling
                methodology and hydrologic modelling are important for understanding
                the chemical, physical, and biological functions provided by
                tributaries and their adjacent wetlands and their effects on downstream
                traditional navigable waters.
                 While EPA regions and Corps districts must exercise judgment to
                identify the OHWM on a case-by-case basis, the regulations identify the
                factors to be applied. These regulations have been further explained in
                RGL 05-05, and the Corps continues to improve regulatory practices
                across the country through ongoing research and the development of
                regional and national OHWM delineation procedures. The agencies will
                apply the regulations, RGL 05-05, and applicable OHWM delineation
                manuals and take other steps as needed to ensure that the OHWM
                identification factors are applied consistently nationwide. Rapanos
                Guidance at 10-11, n. 36.
                 In the Rapanos Guidance, the agencies identify numerous functions
                provided by tributaries and wetlands that are relevant to the
                significant nexus determination. The duration, frequency, and volume of
                flow in a tributary, and subsequently the flow in downstream
                traditional navigable waters, is directly affected by the presence of
                adjacent wetlands that hold floodwaters, intercept sheet flow from
                uplands, and then release waters to tributaries in a more even and
                constant manner. Wetlands may also help to maintain more consistent
                water temperature in tributaries, which is important for some
                [[Page 69438]]
                aquatic species; adjacent wetlands trap and hold pollutants that may
                otherwise reach tributaries (and downstream traditional navigable
                waters) including sediments, chemicals, and other pollutants.
                Tributaries and adjacent wetlands provide habitat (e.g., refuge,
                feeding, nesting, spawning, or rearing young) for many aquatic species
                that also live in traditional navigable waters. Id. at 9. Under the
                Rapanos Guidance, the agencies take into account other relevant
                considerations, including the functions performed by the tributary
                together with the functions performed by any adjacent wetlands.
                 Another specific consideration from the Rapanos Guidance is the
                extent to which the tributary and adjacent wetlands have the capacity
                to carry pollutants (e.g., petroleum wastes, toxic wastes, sediment) or
                flood waters to traditional navigable waters, or to reduce the amount
                of pollutants or flood waters that would otherwise enter traditional
                navigable waters. Id. at 11; citing Rapanos at 782, citing Oklahoma ex
                rel. Phillips v. Guy F. Atkinson Co., 313 U.S. 508, 524-25 (1941)
                (``Just as control over the non-navigable parts of a river may be
                essential or desirable in the interests of the navigable portions, so
                may the key to flood control on a navigable stream be found in whole or
                in part in flood control on its tributaries.'').
                 The agencies under the Rapanos Guidance also evaluate ecological
                functions performed by the tributary and any adjacent wetlands which
                affect downstream traditional navigable waters, such as the capacity to
                transfer nutrients and organic carbon vital to support downstream
                foodwebs (e.g., macroinvertebrates present in headwater streams convert
                carbon in leaf litter making it available to species downstream),
                habitat services such as providing spawning areas for recreationally or
                commercially important species in downstream waters, and the extent to
                which the tributary and adjacent wetlands perform functions related to
                maintenance of downstream water quality such as sediment trapping.
                Rapanos Guidance at 11. In the context of the Rapanos Guidance,
                ecological functions were meant to represent the suite of chemical,
                physical, and biological functions performed by the waters being
                assessed that affect downstream traditional navigable waters.
                 To demonstrate effects on physical integrity of downstream waters,
                the agencies have used evidence of physical connections, such as flood
                water or sediment retention (flood prevention). Indicators of
                hydrologic connections between the water being evaluated and
                jurisdictional waters may also provide evidence of a physical
                connection. In addition, relevant considerations for physical
                connectivity could include rain intensity, duration of rain events or
                wet season, soil permeability, distance of hydrologic connection
                between the water and the traditional navigable water, and depth from
                surface to water table, all of which may indicate evidence of
                connection to stream baseflows, and any preferential flowpaths.
                 Evidence of a significant effect on the chemical integrity of
                foundational waters has been found by identifying the properties of the
                water(s) under evaluation in comparison to the traditional navigable
                water; signs of retention, release, or transformation of nutrients or
                pollutants; and the effect of landscape position on the strength of the
                connection to the nearest jurisdictional water and through those waters
                to a traditional navigable water. Relevant considerations for chemical
                connectivity could include hydrologic connectivity, surrounding land
                use and land cover, the landscape setting, and deposition of chemical
                constituents (e.g., acidic deposition).
                 To determine whether a water has a significant effect on the
                biological integrity of traditional navigable waters, interstate
                waters, or territorial seas, the agencies have identified biological
                factors or uses present in the relevant stream reach, and then
                evaluated the effects of these factors or uses on the downstream
                waters. Examples of biological factors and uses include: Resident
                aquatic or semi-aquatic species present in the water being evaluated,
                the tributary system, and downstream traditional navigable waters
                (e.g., fish, amphibians, aquatic and semi-aquatic reptiles, aquatic
                birds, benthic macroinvertebrates); whether those species show life-
                cycle dependency on the identified aquatic resources (foraging,
                feeding, nesting, breeding, spawning, use as a nursery area, etc.); and
                whether there is reason to expect presence or dispersal around the
                water being evaluated, and if so, whether such dispersal extends to the
                tributary system or beyond or from the tributary system to the water
                being evaluated. In addition, relevant factors influencing biological
                connectivity and effects could include species' life history traits,
                species' behavioral traits, dispersal range, population sizes, timing
                of dispersal, distance between the water being evaluated and a
                traditional navigable water, the presence of habitat corridors or
                barriers, and the number, area, and spatial distribution of habitats.
                Under such an approach, non-aquatic species or species such as non-
                resident migratory birds do not demonstrate a life cycle dependency on
                the identified aquatic resources and are not evidence of a significant
                nexus.
                 As discussed in section V.C.10 of this preamble, the agencies'
                proposed definition of ``significantly affect'' at paragraph (g)
                includes a list of factors that the agencies will consider when
                assessing the significance of the effect of a function. These factors
                are consistent with the approach the agencies used in assessing
                significant nexus under the Rapanos Guidance, and the agencies are
                soliciting comment on whether to include these or other factors, as
                well as whether to include functions identified in the Rapanos Guidance
                or other functions in the proposed rule or in approaches for
                implementing the rule.
                ii. Other Potential Approaches To Implementing the Significant Nexus
                Standard
                 The agencies solicit comment on how to apply the significant nexus
                standard in the field, including whether they should implement the
                significant nexus standard in the proposed rule consistent with the
                Rapanos Guidance for all waters under the proposed rule that require a
                significant nexus evaluation--i.e., certain ``other waters,'' non-
                relatively permanent tributaries, and certain adjacent wetlands (i.e.,
                waters identified in paragraphs (a)(3)(ii), (a)(5)(ii), (a)(7)(iii) of
                the proposed rule). Should the agencies implement the significant nexus
                standard consistent with the Rapanos Guidance, the agencies are seeking
                comment on whether there are clarifications or other issues to be
                addressed to improve that implementation approach. The agencies are
                also seeking comment on other approaches to implementing the
                significant nexus standard, such as a broader, science-based approach
                to some aspects of a significant nexus analysis or an approach that
                tailors the scope of a significant analysis based on facts like the
                geographic region or type of water being assessed, as discussed below.
                (1) Scope of Significant Nexus Analysis for Adjacent Wetlands and
                Tributaries
                 Under the significant nexus standard, waters possess the requisite
                significant nexus if they ``either alone or in combination with
                similarly situated [wet]lands in the region, significantly affect the
                chemical, physical, and biological integrity of other covered waters
                more readily understood as `navigable.''' Rapanos at 780. These
                significant nexus analyses underpin
                [[Page 69439]]
                determinations of jurisdiction for certain categories of waters under
                the proposed rule. However, several terms in this standard were not
                defined in Rapanos. The agencies are soliciting comment on approaches
                for implementing the proposed rule, including regarding (1) which
                waters are ``similarly situated,'' and thus should be analyzed in
                combination, in (2) the ``region,'' for purposes of a significant nexus
                analysis, and (3) the types of functions that should be analyzed to
                determine if waters significantly affect the chemical, physical, or
                biological integrity of traditional navigable waters, interstate
                waters, or the territorial seas. Discussion of the alternative
                approaches regarding relevant functions is in section V.D.2.b.ii.2 of
                this preamble.
                a. Similarly Situated Waters
                 As discussed above, the Rapanos Guidance interpreted ``similarly
                situated'' to mean a tributary and its adjacent wetlands. The agencies
                could implement the final rule consistent with this approach or take an
                approach that interprets which waters are ``similarly situated''
                differently than the Rapanos Guidance. One such approach would be to
                interpret ``similarly situated'' in terms of particular waters that are
                providing common, or similar, functions for downstream waters such that
                it is reasonable to consider their effect together. Such an approach
                could consider tributaries to be similarly situated with other
                tributaries, adjacent wetlands to be similarly situated with adjacent
                wetlands, and ``other waters'' to be similarly situated with ``other
                waters'' (e.g., lakes and ponds with similar functions and geographic
                position on the landscape). Another approach would be to consider
                similarly situated waters to be tributaries of the same flow regime
                (for example, assessing an ephemeral stream in combination with other
                ephemeral streams in the region). The agencies could also consider
                tributaries of the same stream order to be similarly situated (for
                example, assessing all first order streams in combination with other
                first order streams in the region).
                 The agencies note that the best available science supports
                evaluating the connectivity and effects of streams, wetlands, and open
                waters to downstream waters in a cumulative manner in context with
                other streams, wetlands, and open waters. See Technical Support
                Document.
                b. In the Region
                 The agencies could implement the scope of the significant nexus
                analysis (what is considered ``in the region'') consistent with the
                Rapanos Guidance, which relied on a concept of a relevant ``reach'' of
                a tributary--defined as the entire reach of the stream that is of the
                same order (i.e., from the point of confluence, where two lower order
                streams meet to form the tributary, downstream to the point such
                tributary enters a higher order stream). Rapanos Guidance at 10.
                 Alternatively, the agencies could implement what is considered ``in
                the region'' for significant nexus evaluations with an approach
                different from that in the Rapanos Guidance. For example, the relevant
                reach for purposes of considering what is ``in the region'' for a
                significant nexus evaluation could be implemented the way the term
                ``reach'' was interpreted in the NWPR, meaning a section of a stream or
                river along which similar hydrologic conditions exist, such as
                discharge, depth, area, and slope. 85 FR 22290, April 21, 2020. Under
                the NWPR's approach, a reach can be any length of a stream or river,
                but for implementation purposes that length is bounded by similar flow
                characteristics. Similarly, the agencies could implement the ``relevant
                reach'' to incorporate the entire length of the stream that is of the
                same flow regime (i.e., relatively permanent and non-relatively
                permanent flow, or perennial, intermittent, and ephemeral flow). For
                example, if a perennial tributary becomes intermittent and then
                ephemeral and then perennial again, it may be viewed as four separate
                relevant reaches (e.g., perennial reach, intermittent reach, ephemeral
                reach, perennial reach). Alternatively, the agencies could use an
                approach that is substantially similar to the Rapanos Guidance but that
                identifies the relevant reach based on certain hydrologic or geomorphic
                characteristics. For instance, the relevant reach of a tributary could
                rely on factors identified in stream field assessments and monitoring
                protocols such as the similarity of the channel's substrate or
                geomorphic classification. Additional factors identified through field
                observations or remote-sensing could also be used to determine the
                extent of a tributary's relevant reach such as the presence of natural
                features like bedrock outcrops or valley confinements, and non-natural
                features like culverts or road crossings, which can modify or influence
                hydrologic characteristics and geomorphic processes. Aerial and
                satellite imaging, National Hydrography Dataset (NHD) Plus High
                Resolution data, and high resolution digital elevation models could be
                used to evaluate whether hydrologic and geomorphic conditions within a
                channel are similar enough to be defined as the relevant reach of a
                tributary. Another option is for the agencies to interpret a tributary
                for purposes of the significant nexus analysis to be the entire length
                of a stream based on maps or best professional judgment.
                 There are also a range of approaches for determining the ``region''
                in which waters to be assessed lie and which could allow for a more
                regionalized approach to significant nexus assessments. For example,
                the region could be sub-watersheds or the watershed defined by where a
                tributary and its upstream tributaries drain into a traditional
                navigable water, interstate water, or the territorial seas. If the
                watershed draining to the traditional navigable water, interstate
                water, or territorial sea is too large, the watershed could be
                evaluated at a subwatershed scale (e.g., at the hydrologic unit code
                (HUC) 8, 10, or 12 watershed scale). Alternatively, the watershed could
                be considered just the watershed of the relevant reach (i.e.,
                catchment), and the relevant reach could be determined using the
                options described above. Another option is for the watershed to be
                delineated from the downstream-most point of the relevant reach--that
                is, the region would be the watershed that drains to and includes the
                relevant reach in question. Many existing spatial analysis tools based
                on watershed frameworks and elevation models can be used to delineate
                watersheds quickly and reliably in most parts of the country.
                 Other options for determining a ``region'' in which similarly
                situated waters would be considered cumulatively could include a
                narrower interpretation such as waters within a contiguous area of land
                with relatively homogeneous soils, vegetation, and landform (e.g.,
                plain, mountain, valley, etc.) providing similar functions such as
                habitat, water storage, sediment retention, and pollution
                sequestration. This approach would be highly case specific and rely on
                the use of resources such as soil surveys and possibly watershed
                assessment reports to determine those waters that are similarly
                situated within a region.
                 More broadly, ``region'' could be interpreted to mean an ecoregion
                which serves as a spatial framework for the research, assessment,
                management, and monitoring of ecosystems and ecosystem components.
                Ecoregions are areas where ecosystems (and the type, quality, and
                quantity of environmental resources) are generally similar (see https://www.epa.gov/eco-research/ecoregions). Ecoregions are identified by
                [[Page 69440]]
                analyzing the patterns and composition of biotic and abiotic phenomena
                that affect or reflect differences in ecosystem quality and
                integrity.\55\ \56\ These phenomena include geology, landforms, soils,
                vegetation, climate, land use, wildlife, and hydrology. Under the
                ecoregion approach, similarly situated waters would be considered
                cumulatively within an ecoregion (see, e.g., https://www.epa.gov/eco-research/ecoregions-north-america). The scale of ecoregion (e.g., Level
                I, Level II, Level III, or Level IV ecoregions identified by EPA in
                North America) used for determining the ``region'' could be quite
                broad, such as the 12 different Level I ecological regions in the
                continental United States or narrower like the 105 different Level III
                ecological regions in the continental United States or the 967 Level IV
                ecoregions in the conterminous United States. Because Level I
                ecoregions are quite large, considerations of similarly situated waters
                at the Level I ecoregion scale could potentially obscure the measurable
                effects of a single aquatic resource on a downstream traditional
                navigable water, interstate water, or territorial sea. However, the
                scale of the similarly situated analysis within an ecoregion could be
                refined using the smaller Level III or Level IV ecoregions which allow
                local characteristics to be identified and are more specifically
                oriented towards environmental management strategies. Under this
                approach in a jurisdictional analysis, scientific literature describing
                or studying characteristics of the Level III or Level IV ecoregions
                could be used to inform the evaluation of specific ecological functions
                performed by similarly situated waters. A benefit of using this
                approach is that ecoregions are spatial datasets which have been, or
                could be, incorporated into many existing spatial analysis tools and
                mapping platforms. In addition, stakeholders have called for
                acknowledging regional differences in the definition of ``waters of the
                United States,'' and an ecoregion approach could allow for such
                consideration in implementation.
                ---------------------------------------------------------------------------
                 \55\ Omernik, J.M. 1987. Ecoregions of the conterminous United
                States. Map (scale 1:7,500,000). Annals of the Association of
                American Geographers 77(1):118-125.
                 \56\ Omernik, J.M. 1995. Ecoregions: A spatial framework for
                environmental management. In: Biological Assessment and Criteria:
                Tools for Water Resource Planning and Decision Making. Davis, W.S.
                and T.P. Simon (eds.), Lewis Publishers, Boca Raton, FL. p. 49-62.
                ---------------------------------------------------------------------------
                 In addition to ecoregions, other methods of mapping boundaries
                where similarly situated waters could be considered cumulatively for a
                significant nexus analysis would be to rely on hydrologic landscape
                regions or physiographic groupings. Hydrologic landscape regions are
                groups of watersheds that are clustered together on the basis of
                similarities in land-surface form, geologic texture, and climate
                characteristics.\57\ Hydrologic landscape regions are based on a
                concept that reflects fundamental hydrologic processes that are
                expected to affect water quality and other environmental
                characteristics. Based on a commonly used method to delineate
                hydrologic landscape regions that was developed by the USGS, there are
                20 regions that cover the entire United States.\58\ This method could
                present similar challenges as the Level I ecoregion approach described
                above, whereby the hydrologic landscape region scale obscures the
                measurable effects of single aquatic resources. Alternatively, the
                agencies could rely on well-established physiographic divisions based
                on topography, geology, and geomorphology, including the eight
                physiographic regions across the contiguous United States, the 25
                physiographic provinces within those regions, or the 85 physiographic
                sections within those regions (available at https://water.usgs.gov/GIS/metadata/usgswrd/XML/physio.xml).
                ---------------------------------------------------------------------------
                 \57\ Winter, T.C., 2001. The concept of hydrologic landscapes:
                Journal of the American Water Resources Association, v. 37, p. 335-
                349.
                 \58\ Wolock, D.M. 2003. Hydrologic landscape regions of the
                United States (No. 2003-145). US Geological Service.
                ---------------------------------------------------------------------------
                (2) Other Waters
                 The agencies seek comment on potential approaches to address a
                significant nexus analysis for waters under the ``other waters''
                provision of the proposed rule. As discussed in section V.C.3 of this
                preamble, ``other waters'' were not addressed by the Rapanos Guidance.
                The agencies could adopt the approach used in the SWANCC Guidance,
                whereby field staff were directed to seek approval from agency
                headquarters before asserting jurisdiction over isolated waters that
                are intrastate and non-navigable. See 68 FR at 1996, January 15, 2003.
                As a matter of practice since the issuance of the SWANCC Guidance, the
                Corps has not asserted jurisdiction over such ``other waters.'' The
                agencies would not be precluded as a legal matter from asserting
                jurisdiction over ``other waters'' under this proposed rule, which
                would retain the ``other waters'' provision from the 1986 regulations
                and add the relatively permanent and significant nexus standards, but
                following the SWANCC Guidance approach would require an additional
                approval process before the agencies asserted jurisdiction. The
                agencies could also modify the prior approach by identifying a
                subsection of ``other waters'' that could be determined jurisdictional
                without headquarters' authorization, such as lakes and ponds which meet
                the definition of ``adjacent,'' but do not fall within the adjacent
                wetlands provision because they are open waters, not wetlands (e.g.,
                oxbow lakes and ponds).
                 ``Other waters'' that meet the definition of ``adjacent'' could be
                treated like adjacent wetlands under the Rapanos Guidance. Under such
                an approach, the agencies could adopt the same interpretation of
                ``similarly situated'' that is used to complete a significant nexus
                determination for adjacent wetlands (see section V.D.2.b.ii.1 of this
                preamble), or the agencies could adopt a different interpretation of
                ``similarly situated'' that is specifically applicable to ``other
                waters.''
                 The various options for implementing significant nexus are not
                mutually exclusive and the agencies are interested in any other
                approaches for assessing significant nexus under the proposed rule,
                particularly approaches that utilize existing science-based tools and
                resources to assist in predictability and ease of implementation for
                the public and the agencies.
                3. Resources for Making Jurisdictional Determinations
                 Many field-based and remote tools and sources of data are available
                to determine Clean Water Act jurisdiction under the proposed rule. In
                some cases, a property owner may be able to determine whether a
                property includes a ``water of the United States'' based on observation
                or experience. In other cases, a property owner may seek assistance
                from a consultant to assess the jurisdictional status of features on
                their property. Property owners may also seek a jurisdictional
                determination from the Corps, which provides jurisdictional
                determinations as a public service. When conducting a jurisdictional
                determination, the Corps will review any documentation that a property
                owner, or consultant, provides to assist in making a jurisdictional
                determination. EPA staff also regularly assess the jurisdictional
                status of waters in implementing Clean Water Act programs. The agencies
                expect that EPA and Corps staff, as well as private consultants, would
                be the primary users of the tools and sources of remote data described
                below, and they have ample
                [[Page 69441]]
                experience in using them from prior regulatory regimes.
                 The resources covered in this section include tools for identifying
                relatively permanent tributaries (section V.D.3.a of this preamble);
                tools for identifying wetlands adjacent to traditional navigable
                waters, interstate waters, the territorial seas, impoundments of
                jurisdictional waters, or tributaries (section V.D.3.b of this
                preamble); and tools for applying a significant nexus standard (section
                V.D.3.c of this preamble). This section presents a non-exclusive list
                of tools that the agencies have used in the past and will continue to
                use to assist in making jurisdictional decisions, but other tools could
                also be used to determine jurisdiction. The agencies have also
                identified a number of recent advancements in the data, tools, and
                methods that can be used to make jurisdictional decisions (section
                V.D.3.d of this preamble).
                a. Identifying Relatively Permanent Tributaries
                 Relatively permanent tributaries include rivers, streams, and other
                hydrographic features with standing or flowing bodies of water, and may
                also include certain lakes and ponds. These features can be identified
                on the landscape using various remote sensing resources such as USGS
                stream gage data (available at https://waterdata.usgs.gov/nwis/rt),
                USGS topographic maps (available at https://www.usgs.gov/core-science-systems/ngp/tnm-delivery/topographic-maps), high-resolution elevation
                data and associated derivatives (e.g., slope or curvature metrics),
                Federal Emergency Management Agency (FEMA) flood zone maps (available
                at https://msc.fema.gov/portal/home), NRCS soil maps (available at
                https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx), NHD
                data, National Wetland Inventory (NWI) data, maps and geospatial
                datasets from state, tribal, or local governments, and/or aerial or
                satellite imagery. For example, tributaries are observable in aerial
                imagery and high-resolution satellite imagery by their topographic
                expression, characteristic linear and curvilinear patterns, dark
                photographic tones, or the presence of riparian vegetation. USGS
                topographic maps often include different symbols to indicate mapped
                hydrographic features such as perennial and intermittent tributaries
                (see ``Topographic Map Symbols,'' available at https://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf). Due to limitations
                associated with some remote tools, field verification for accuracy may
                be necessary, and some examples of field indicators will be discussed
                in more detail below.
                 Under the Rapanos Guidance, tributaries may be considered
                relatively permanent if they typically flow year-round or have
                continuous flow at least seasonally (e.g., typically three months). A
                key factor that the agencies typically consider when assessing the
                length and timing of expected ``seasonal'' flows is the geographic
                region. The time period, including length, constituting ``seasonal''
                varies across the country due to many relevant factors including
                climate, hydrology, topography, soils, and other conditions. For
                example, in parts of the southeastern United States (Southeast),
                precipitation is distributed somewhat uniformly throughout the year,
                but increased evapotranspiration during the growing season can reduce
                surficial ground water levels and lead to reduced or absent surface
                flows late in the growing season (e.g., late summer or early autumn).
                Consequently, ``seasonal'' flows in the Southeast may typically occur
                in the winter or early spring. In other areas, snowmelt drives
                streamflow more than rainfall, with seasonal flow coinciding with
                warming temperatures typically in the spring or early summer. In
                addition, the agencies have found that two months of continuous flow,
                for example, is considered ``seasonal'' flow in certain regions of the
                country and can be sufficient to support a relatively permanent
                designation.\59\ Sources of information that can facilitate the
                evaluation of seasonal flow from snowmelt are NOAA national snow
                analyses maps (available at https://www.nohrsc.noaa.gov/nsa/), NRCS
                sources (available at https://www.wcc.nrcs.usda.gov/snow/), or use of
                hydrographs to indicate a large increase in stream discharge due to the
                late spring/early summer thaws of melting snow. The agencies have
                experience evaluating seasonal flow and will continue to use multiple
                tools, including remote and field-based indicators to inform decisions.
                ---------------------------------------------------------------------------
                 \59\ See, e.g., Memorandum to Assert Jurisdiction for NWP-2007-
                945 (January 23, 2008), available at https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll5/id/1437.
                ---------------------------------------------------------------------------
                 While not providing explicit flow classifications (e.g., perennial,
                intermittent, or ephemeral), various remote or desktop tools can help
                the agencies and the public better understand streamflow and inform
                determinations of flow classifications. These tools include local maps,
                StreamStats by the USGS (available at https://streamstats.usgs.gov/ss/
                ), Probability of Streamflow Permanence (PROSPER) by the USGS, which
                provides streamflow permanence probabilities during the summer for
                stream reaches in the Pacific Northwest (available at https://www.usgs.gov/centers/wy-mt-water/science/probability-streamflowpermanence-prosper), and NRCS hydrologic tools and soil maps.
                Other tools include regional desktop tools that provide for the
                hydrologic estimation of a discharge sufficient to generate
                intermittent or perennial flow (e.g., a regional regression analysis or
                hydrologic modeling), or modeling tools using drainage area,
                precipitation data, climate, topography, land use, vegetation cover,
                geology, and/or other publicly available information. Some models that
                are developed for use at the reach scale may be localized in their
                geographic scope.
                 Remote or desktop tools can also illustrate the relative permanence
                of flow. Aerial photographs showing visible water on multiple dates can
                provide evidence of the sufficient frequency and duration of surface
                flow to facilitate a potential flow classification. Aerial photographs
                may also show other indicators commonly used to identify the presence
                of an OHWM (see definition of OHWM in section V.C.9.d of this preamble
                and https://www.erdc.usace.army.mil/Media/Fact-Sheets/Fact-Sheet-Article-View/Article/486085/ordinary-high-water-mark-ohwm-research-development-and-training/). These may include the destruction of
                terrestrial vegetation, the absence of vegetation in a channel, and
                stream channel morphology with evidence of scour, material sorting, and
                deposition. These indicators from aerial photographs can be correlated
                to the presence of USGS stream data to support a potential flow
                classification for a tributary. In addition to aerial photographs,
                desktop tools, such as a regional regression analysis and the
                Hydrologic Modeling System (HEC-HMS), provide for the hydrologic
                estimation of stream discharge in tributaries under regional
                conditions. The increasing availability of light detection and ranging
                (LIDAR) derived data can also be used to help implement this proposed
                rule. Where LIDAR data have been processed to create elevation data
                such as a bare earth model, detailed depictions of the land surface are
                available and subtle elevation changes can indicate a tributary's bed
                and banks and channel morphology. Visible linear and curvilinear
                incisions on a bare earth model can help inform the potential
                [[Page 69442]]
                flow regime of a water in greater detail than aerial photography
                interpretation alone. Several tools (e.g., TauDEM, Whitebox, GeoNet)
                can assist in developing potential stream networks based on
                contributing areas, curvature, and flowpaths using GIS. Potential
                LIDAR-indicated tributaries can be correlated with aerial photography
                or high-resolution satellite imagery interpretation and USGS stream
                gage data, to reasonably conclude the presence of an OHWM and shed
                light on the potential flow regime.
                 Field indicators for the region can be used to verify desktop
                assessments of the relative permanence of a tributary, when necessary.
                Geomorphic indicators could include active/relict floodplain, substrate
                sorting, clearly defined and continuous bed and banks, depositional
                bars and benches, and recent alluvial deposits. Hydrologic indicators
                might include wrack/drift deposits, hydric soils, or water-stained
                leaves. Biologic indicators could include aquatic mollusks, crayfish,
                benthic macroinvertebrates, algae, and wetland or submerged aquatic
                plants. Regionalized streamflow duration assessment methods (SDAMs)
                that use physical and biological field indicators, such as the presence
                of hydrophytic vegetation and benthic macroinvertebrates, can also be
                used to determine the flow duration class of a tributary 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). EPA, the Corps, and the
                State of Oregon developed a regionalized SDAM that has been validated
                for use throughout the Pacific Northwest (available at http://www.epa.gov/measurements/streamflow-duration-assessment-method-pacific-northwest). EPA and the Corps have also developed a beta SDAM for the
                arid West (available at https://www.epa.gov/streamflow-duration-assessment/beta-streamflow-duration-assessment-method-arid-west) and
                are working to develop additional regionalized SDAMs in other parts of
                the country. Flow duration classifications can then be used to assist
                in determining the relative permanence of the tributary. Ultimately,
                multiple indicators, data points, and sources of information may be
                used to determine flow classification.
                b. Identifying Wetlands Adjacent to Traditional Navigable Waters,
                Interstate Waters, Territorial Seas, Impoundments, or Tributaries
                 Before determining if a wetland is jurisdictional, the agencies
                first determine if the wetland in question meets the definition of
                ``wetlands'' (see section V.C.9.a of this preamble). As under prior
                regimes, wetlands are identified in the field in accordance with Corps'
                1987 Wetland Delineation Manual and applicable regional delineation
                manuals. Field work is often necessary to confirm the presence of a
                wetland and to accurately delineate its boundaries. However, in
                addition to field observations on hydrology, vegetation, and soils,
                remote tools and resources can be used to support the identification of
                a wetland, including USGS topographic maps (available at https://www.usgs.gov/core-science-systems/ngp/tnm-delivery/topographic-maps),
                NRCS soil maps and properties of soils including flood frequency and
                duration, ponding frequency and duration, hydric soils, and drainage
                class (available at https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx or via the NRCS Soil Survey Geographic Database
                (SSURGO) available at https://catalog.data.gov/dataset/soil-survey-geographic-database-ssurgo), aerial or high-resolution satellite
                imagery, high-resolution elevation data (e.g., https://apps.nationalmap.gov/downloader/#/), and NWI maps (available at https://www.fws.gov/wetlands/data/mapper.html).
                 Once a feature is identified as a wetland, if the wetland itself is
                not a traditional navigable water (i.e., it is not a tidal wetland) or
                an interstate water, the agencies assess whether it is adjacent to a
                traditional navigable water, interstate water, territorial sea,
                jurisdictional impoundment, or jurisdictional tributary. A variety of
                remote tools can help to assess adjacency, including maps, high-
                resolution elevation data, aerial photographs, and high-resolution
                satellite imagery. For example, USGS topographic maps, elevation data,
                and NHD data may identify a physical barrier or illustrate the location
                of the traditional navigable water, interstate water, territorial sea,
                jurisdictional impoundment, or jurisdictional tributary; the wetland's
                proximity to the jurisdictional water; and the nature of topographic
                relief between the two aquatic resources. Aerial photographs or high-
                resolution satellite imagery may illustrate hydrophytic vegetation from
                the boundary (e.g., ordinary high water mark for non-tidal waters or
                high tide line for tidal waters) of the traditional navigable water,
                interstate water, territorial sea, jurisdictional impoundment, or
                jurisdictional tributary to the wetland boundary, or the presence of
                water or soil saturation. NRCS soil maps may identify the presence of
                hydric soil types, soil saturation, or potential surface or subsurface
                hydrologic connections. Additionally, methods that overlay depressions
                on the landscape with hydric soils and hydrophytic vegetation can be
                used to identify likely wetlands and hydrologic connections. NWI maps
                may identify that the wetlands are near the traditional navigable
                water, interstate water, territorial sea, jurisdictional impoundment,
                or jurisdictional tributary. Field work can help confirm the presence
                and location of the OHWM or high tide line of the traditional navigable
                water, interstate water, territorial sea, jurisdictional impoundment,
                or jurisdictional tributary and can provide additional information
                about the wetland's potential adjacency to that water (e.g., by
                traversing the landscape from the traditional navigable water,
                interstate water, territorial sea, jurisdictional impoundment, or
                jurisdictional tributary to the wetland and examining topographic and
                geomorphic features, as well as hydrologic and biologic indicators).
                Wetlands adjacent to traditional navigable waters, interstate waters,
                or the territorial seas do not need further analysis to determine if
                they are ``waters of the United States.''
                 For a wetland adjacent to relatively permanent, non-navigable
                tributaries and relatively permanent impoundments of jurisdictional
                waters, similar remote tools and resources as those described above may
                be used to identify if the wetland has a continuous surface connection
                to such waters. The tools and resources most useful for addressing this
                standard are those that reveal breaks in the surface connection between
                the wetland and the relatively permanent water, such as separations by
                uplands, or a berm, dike, or similar feature. For example, USGS
                topographic maps may show topographic highs between the two features,
                or simple indices can be calculated based on topography to indicate
                where these connectivity breaks occur. FEMA flood zone or other
                floodplain maps may indicate constricted floodplains along the length
                of the tributary channel with physical separation of flood waters that
                could indicate a break. High-resolution elevation data can illustrate
                topographic highs between the two features that
                [[Page 69443]]
                extend along the tributary channel. Aerial photographs or high-
                resolution satellite imagery may illustrate upland vegetation along the
                tributary channel between the two features, or bright soil signatures
                indicative of higher ground. NRCS soil maps may identify mapped linear,
                upland soil types along the tributary channel. Field work may help to
                confirm the presence and location of the relatively permanent, non-
                navigable tributary's OHWM. In addition, field work may confirm whether
                there is a continuous physical connection between the wetland and the
                relatively permanent, non-navigable tributary, or identify breaks that
                may sever the continuous surface connection (e.g., by traversing the
                landscape from the tributary to the wetland and examining topographic
                and geomorphic features, as well as hydrologic and biologic
                indicators).
                 For adjacent wetlands that lack a continuous surface connection to
                jurisdictional relatively permanent tributaries or jurisdictional
                relatively permanent impoundments or that are adjacent to non-
                relatively permanent tributaries, the agencies will conduct a
                significant nexus analysis to assess if the wetlands are
                jurisdictional. Tools to assess if the adjacent wetlands significantly
                affect foundational waters are discussed in section V.D.3.c of this
                preamble.
                c. Applying the Significant Nexus Standard
                 The agencies have used many tools and sources of information to
                assess significant effects on the chemical, physical, and biological
                integrity of downstream traditional navigable waters, interstate
                waters, or the territorial seas. Some tools and resources that the
                agencies have used to provide and evaluate evidence of a significant
                effect on the physical integrity of foundational waters include USGS
                stream gage data, floodplain maps, statistical analyses, hydrologic
                models and modeling tools such as USGS's StreamStats (available at
                https://streamstats.usgs.gov/ss/) or the Corps' Hydrologic Engineering
                Centers River System Analysis System (HEC-RAS), physical indicators of
                flow such as the presence and characteristics of a reliable OHWM with a
                channel defined by bed and banks, or other physical indicators of flow
                including such characteristics as shelving, wracking, water staining,
                sediment sorting, and scour, information from NRCS soil surveys,
                precipitation and rainfall data, and NRCS snow telemetry (SNOTEL) data
                or NOAA national snow analyses maps.
                 To evaluate the evidence of a significant effect on the biological
                integrity of foundational waters, the agencies and practitioners have
                used tools and resources such as: population survey data and reports
                from federal, state, and tribal resource agencies, natural history
                museum collections databases, bioassessment program databases, fish
                passage inventories, U.S. Fish and Wildlife Service (FWS) Critical
                Habitat layers, species distribution models, and scientific literature
                and references from studies pertinent to the distribution and natural
                history of the species under consideration.
                 Tools and resources that provide and evaluate evidence of a
                significant effect on the chemical integrity of foundational waters
                include data from USGS water quality monitoring stations, state,
                tribal, and local water quality reports, water quality monitoring and
                assessment databases, EPA's How's My Waterway (available at https://www.epa.gov/waterdata/hows-my-waterway), which identifies Clean Water
                Act section 303(d) listed waters, water quality impairments, and total
                maximum daily loads, watershed studies, stormwater runoff data or
                models, EPA's NEPAssist (available at https://www.epa.gov/nepa/nepassist), which provides locations and information on wastewater
                discharge facilities and hazardous-waste sites, the National Land Cover
                Database (NLCD), and scientific literature and references from studies
                pertinent to the parameters being reviewed. EPA has developed a web-
                based interactive water quality and quantity modeling system
                (Hydrologic and Water Quality System, HAWQS; available at https://www.epa.gov/waterdata/hawqs-hydrologic-and-water-quality-system) that
                is being used to assess cumulative effects of wetlands on other waters
                they may drain into. Additional approaches to quantifying the
                hydrologic storage capacity of wetlands include statistical models,
                such as pairing LIDAR-based topography with precipitation totals. Both
                statistical and process-based models have been used to quantify the
                nutrient filtering capabilities of non-floodplain wetlands, and in some
                cases to assess the effects of non-floodplain wetland nutrient removal,
                retention, or transformation on downstream water quality. Evaluations
                of a significant effect on the chemical integrity of a traditional
                navigable water, interstate water, or territorial sea may include
                qualitative reviews of available information or incorporate
                quantitative analysis components including predictive transport
                modeling.
                 A variety of modeling approaches can be used to quantify the
                connectivity and cumulative effects of wetlands, including non-
                floodplain wetlands, on other waters. Some examples include the Soil
                and Water Assessment Tool (SWAT, available at https://swat.tamu.edu/),
                the Hydrologic Simulation Program in Fortran (see https://www.epa.gov/ceam/hydrological-simulation-program-fortran-hspf), and DRAINMOD for
                Watersheds (DRAINWAT, available at https://www.bae.ncsu.edu/agricultural-water-management/drainmod/). Other examples of models
                applicable to identifying effects of wetlands on downstream waters
                include the USGS hydrologic model MODFLOW (available at https://www.usgs.gov/mission-areas/water-resources/science/modflow-and-related-programs?qt-science_center_objects=0#qt-science_center_objects) and the
                USGS flow simulation model VS2DI (available at https://www.usgs.gov/software/vs2di-version-13).
                d. Advancements in Implementation Data, Tools, and Methods
                 Since the Rapanos decision, there have been dramatic advancements
                in the data, tools, and methods used to make jurisdictional
                determinations, including in the digital availability of information
                and data. In 2006, when the agencies began to implement the Rapanos and
                Carabell decisions, there were fewer implementation tools and support
                resources to guide staff in defensible jurisdictional decision-making
                under the relatively permanent and significant nexus standards. Agency
                staff were forced to heavily rely on information provided in applicant
                submittals and available aerial imagery to make jurisdictional
                decisions or to schedule an in-person site visit to review the property
                themselves. The U.S. Army Corps of Engineers Jurisdictional
                Determination Form Instructional Guidebook encouraged practitioners to
                utilize maps, aerial photography, soil surveys, watershed studies,
                scientific literature, previous jurisdictional determinations for the
                review area, and local development plans to complete accurate
                jurisdictional decisions or analysis. For more complicated situations
                or decisions involving significant nexus evaluations, the Guidebook
                encouraged practitioners to identify and evaluate the functions
                relevant to the significant nexus by incorporating literature citations
                and/or references from studies pertinent to the parameters being
                reviewed. For significant nexus decisions specifically, the Guidebook
                [[Page 69444]]
                instructed Corps field staff to consider all available hydrologic
                information (e.g., gage data, precipitation records, flood predictions,
                historic records of water flow, statistical data, personal
                observations/records, etc.) and physical indicators of flow including
                the presence and characteristics of a reliable OHWM.
                 The Corps also issued Regulatory Guidance Letter (RGL) No. 07-01
                \60\ in 2007 that laid out principal considerations for evaluating the
                significant nexus of a tributary and its adjacent wetlands which
                included the volume, duration, and frequency of flow of water in the
                tributary, proximity of the tributary to a traditional navigable water,
                and functions performed by the tributary and its adjacent wetlands.
                This RGL highlighted wetland delineation data sheets, delineation maps,
                and aerial photographs as important for adequate information to support
                all jurisdictional decision-making. Gathering the data necessary to
                support preliminary or approved jurisdictional decisions was often time
                consuming for staff and the regulated public, and there were not many
                nationally available repositories for much of the information that the
                agency staff utilized in decision-making, particularly during the first
                years of implementing of the guidance. Despite these challenges, the
                agencies and others in the practitioner community gained significant
                collective experience implementing the relatively permanent and
                significant nexus standards from 2006 to 2015.
                ---------------------------------------------------------------------------
                 \60\ It should be noted that RGL No. 07-01 was later superseded
                by RGL 08-02 and RGL 16-01, neither of which addressed significant
                nexus evaluations.
                ---------------------------------------------------------------------------
                 Since 2015, there have been dramatic improvements to the quantity
                and quality of water resource information available on the internet.
                The agencies can use online mapping tools to determine whether waters
                are connected or sufficiently close to a water of the United States,
                and new user interfaces have been developed that make it easier and
                quicker to access information from a wide variety of sources.
                Furthermore, some information used to only be available in hard-copy
                paper files, including water resource inventories and habitat
                assessments, and many of these resources have been made available
                online or updated with new information. An overview of several tools
                and data that have been developed or improved since 2015 can help
                demonstrate how the agencies are now able to make case-specific
                evaluations more quickly and consistently than ever before.
                 Advancements in geographic information systems (GIS) technology and
                cloud-hosting services have led to an evolution in user interfaces for
                publicly available datasets frequently used in jurisdictional decision-
                making such as the NWI, USGS NHD, soil surveys, aerial imagery and
                other geospatial analysis tools like USGS StreamStats. Not only are the
                individual datasets more easily accessible to users, but it has also
                become much easier for users to quickly integrate these various
                datasets using desktop or online tools like map viewers to consolidate
                and evaluate the relevant data in one visual platform. The EPA
                Watershed Assessment, Tracking, and Environmental Results System
                (WATERS) GeoViewer is an example of a web mapping application that
                provides accessibility to many spatial dataset layers like NHDPlus and
                watershed reports for analysis and interpretation. Other websites like
                the Corps' Jurisdictional Determinations and Permits Decision site and
                webservices like EPA's Enforcement and Compliance History Online (ECHO)
                Map Services allow users to find geospatial and technical information
                about Clean Water Act section 404 and NPDES permitted discharges.
                Information on approved jurisdictional determinations finalized by the
                Corps is also available on the Corps' Jurisdictional Determinations and
                Permit Decisions site and EPA's Clean Water Act Approved Jurisdictional
                Determinations website.
                 The data that are available online have increased in quality as
                well as quantity. The NHD has undergone extensive improvements in data
                availability, reliability, and resolution since 2015, including the
                release of NHDPlus High Resolution datasets for the conterminous U.S.
                and Hawaii, with Alaska under development. One notable improvement in
                NHD data quality is that the flow-direction network data is much more
                accurate than in the past. Improvements have also been made to the NWI
                website and geospatial database, which has served as the primary source
                of wetland information in the United States for many years. In 2016,
                NWI developed a more comprehensive dataset (NWI Version 2) that is
                inclusive of all surface water features in addition to wetlands. The
                agencies can use this dataset to help assess potential hydrologic
                connectivity between waterways and wetlands in support of
                jurisdictional decisions. For example, the NWI Version 2 dataset can be
                used in part to help the agencies identify wetlands that do not meet
                the definition of adjacent (``other waters''). This NWI Version 2
                dataset provides more complete geospatial data on surface waters and
                wetlands than has been available in the past and provides a more
                efficient means to make determinations of flow and water movement in
                surface water basins and channels, as well as in wetlands.
                 The availability of aerial and satellite imagery has improved
                dramatically since 2015, which is used to observe the presence or
                absence of flow and identify relatively permanent flow in tributary
                streams and hydrologic connections to waters. The agencies often use a
                series of aerial and satellite images, spanning multiple years and
                taken under normal climatic conditions, to determine the flow
                classification for a tributary, as a first step to determine if
                additional field-based information is needed to determine the flow
                classification. The growth of the satellite imagery industry through
                services such as DigitalGlobe (available at https://discover.digitalglobe.com/) in addition to resources for aerial
                photography and imagery, such as USGS EarthExplorer (available at
                https://earthexplorer.usgs.gov/) and National Aeronautics and Space
                Administration (NASA) Earth Data (available at https://earthdata.nasa.gov/) have reduced the need to perform as many field
                investigations to verify Clean Water Act jurisdiction, though some of
                these services charge a fee for use. The USGS Landsat Level-3 Dynamic
                Surface Water Extent (DSWE) product (available at https://www.usgs.gov/core-science-systems/nli/landsat/landsat-dynamic-surface-water-extent?qt-science_support_page_related_con=0#qt-science_support_page_related_con) is a specific example of a tool that
                may be useful for identifying surface water inundation on the landscape
                in certain geographic areas.
                 Similarly, the availability of LIDAR data has increased in
                availability and utility for determining Clean Water Act jurisdiction.
                Where LIDAR data have been processed to create a bare earth model,
                detailed depictions of the land surface reveal subtle elevation changes
                and characteristics of the land surface, including the identification
                of tributaries. LIDAR-indicated tributaries can be correlated with
                aerial photography interpretation to reasonably conclude the presence
                of a channel with relatively permanent flow in the absence of a field
                visit. The agencies have been using such remote sensing and desktop
                tools to assist with identifying jurisdictional tributaries for many
                years, and such tools are particularly critical where data from the
                [[Page 69445]]
                field are unavailable or a field visit is not possible. High-resolution
                LIDAR data are becoming more widespread for engineering and land use
                planning purposes.
                 Since 2015, tools have been developed that automate some of the
                standard practices the agencies rely on to assist in determinations.
                One example of this automation is the Antecedent Precipitation Tool
                (APT), which was released to the public in 2020 and had been used
                internally by the agencies prior to its public release. The APT is a
                desktop tool developed by the Corps and is commonly used by the
                agencies to help determine whether field data collection and other
                site-specific observations occurred under normal climatic conditions.
                In addition to providing a standardized methodology to evaluate normal
                precipitation conditions (``precipitation normalcy''), the APT can also
                be used to assess the presence of drought conditions, as well as the
                approximate dates of the wet and dry seasons for a given location. As
                discussed in section V.B.3 of this preamble, above, precipitation data
                are often not useful in providing evidence as to whether a surface
                water connection exists in a typical year, as required by the NWPR.
                However, the agencies have long used the methods employed in the APT to
                provide evidence that wetland delineations are made under normal
                circumstances or to account for abnormalities during interpretation of
                data. The development and public release of the APT has accelerated the
                speed at which these analyses are completed, standardized methods,
                which reduces errors, and enabled more people to perform these analyses
                themselves, including members of the public. The APT will continue to
                be an important tool to support jurisdictional decision-making.
                 Site visits are still sometimes needed to perform on-site
                observations of surface hydrology or collect field-based indicators of
                relatively permanent flow (e.g., the presence of riparian vegetation,
                or certain aquatic macroinvertebrates). The methods and instruments
                used to collect field data have also improved since 2015, such as the
                development of rapid, field-based SDAMs that use physical and
                biological indicators to determine the flow duration class of a stream
                reach. The agencies have previously used existing SDAMs developed by
                federal and state agencies to identify perennial, intermittent, or
                ephemeral streams, and will continue to use these tools whenever they
                are determined to be a reliable source of information for the specific
                water feature of interest. The agencies are currently working to
                develop region-specific SDAMs for nationwide coverage, which will
                promote consistent implementation across the United States in a manner
                that accounts for differences between each ecoregion. Additional
                information on the agencies' efforts to develop SDAMs is available at
                https://www.epa.gov/streamflow-duration-assessment.
                E. Publicly Available Jurisdictional Information and Permit Data
                 The agencies intend to 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 Clean Water Act section 404 permit decisions.
                Similarly, EPA maintains a website at https://watersgeo.epa.gov/cwa/CWA-JDs/ that presents information on approved jurisdictional
                determinations made by the Corps under the Clean Water Act since August
                28, 2015. These websites will incorporate approved jurisdictional
                determinations made under the revised definition of ``waters of the
                United States.'' EPA also maintains on its website information on
                certain dischargers permitted under Clean Water Act section 402,
                including the Permit Compliance System and Integrated Compliance
                Information System database (https://www.epa.gov/enviro/pcs-icis-overview), as well as the EnviroMapper (https://enviro.epa.gov/enviro/em4ef.home), and How's My Waterway (https://www.epa.gov/waterdata/hows-my-waterway). The agencies also intend to provide links to the public
                to any guidance, forms, or memoranda of agreement relevant to the
                definition of ``waters of the United States.''
                 EPA and the Army have also been working with other federal agencies
                on improving aquatic resource mapping and modeling, including working
                with the Department of Interior (DOI) to better align their regulatory
                needs with DOI's existing processes and national mapping capabilities.
                EPA, USGS, and FWS have a long history of working together to map the
                nation's aquatic resources. The agencies will continue to collaborate
                with DOI to enhance the NHD, NWI, and other products to better map the
                nation's water resources while enhancing the utility of such geospatial
                products to the Clean Water Act programs that EPA and the Corps
                implement.
                F. Placement of the Definition of ``Waters of the United States'' in
                the Code of Federal Regulations
                 The definition of ``waters of the United States'' had historically
                been placed in eleven locations in the Code of Federal Regulations
                (CFR). For the sake of simplicity, in the NWPR, the agencies codified
                the definition of ``waters of the United States'' in only two places in
                the CFR--in Title 33 of the CFR, which implements the Corps' statutory
                authority, at 33 CFR 328.3, and in Title 40, which generally implements
                EPA's statutory authority, at 40 CFR 120.2. In the sections of the CFR
                where EPA's definition previously existed, 40 CFR 110.1, 112.2, 116.3,
                117.1, 122.2, 230.3, 232.2, 300.5, 302.3, 401.11, and Appendix E to 40
                CFR part 300, the NWPR cross-references the newly created section of
                the regulations containing the definition of ``waters of the United
                States.'' The agencies placed EPA's definition of ``waters of the
                United States'' in a previously unassigned part of 40 CFR and stated
                that the change in placement had no implications on Clean Water Act
                program implementation; rather, the placement made it clearer to
                members of the public that there is a single definition of ``waters of
                the United States'' applicable to the Clean Water Act and its
                implementing regulations. 85 FR 22328-29, April 21, 2020. The agencies
                agree with this approach and propose no change to the placement of the
                definition of ``waters of the United States.'' As the agencies
                indicated in the NWPR, the placement of the definition in two
                locations, at 33 CFR 328.3 and 40 CFR 120.2, increases convenience for
                the reader but has no substantive implications for the scope of Clean
                Water Act jurisdiction. 85 FR 22328, April 21, 2020.
                 The agencies are proposing to delete the definition of ``navigable
                waters'' at 120.2 and to add it to the ``purpose and scope'' of part
                120 at 40 CFR 120.1. The agencies are also proposing to add additional
                clarifying text to the ``purpose and scope'' at 40 CFR 120.1. The
                agencies intend this to be an editorial and clarifying change and not a
                substantive change from EPA's regulations at 40 CFR 120. The agencies
                believe that this minor revision adds consistency between EPA's
                regulations at 40 CFR 120 and the Corps' regulations defining ``waters
                of the United States'' at 33 CFR 328.3. As a result of this non-
                substantive revision, the agencies' definitions would have parallel
                numerical and alphabetical subsections, providing clarity for the
                public. The Corps similarly includes the
                [[Page 69446]]
                definition of ``navigable waters'' within 33 CFR 328.1, which contains
                the purpose of the Corps' regulations at part 328. The agencies propose
                to retain the same definition of ``navigable waters'' within 40 CFR
                120.1 as the term is defined at section 502(7) of the Clean Water Act
                and as it was defined in the NWPR at 40 CFR 120.2, which is ``the
                waters of the United States, including the territorial seas.''
                 The agencies solicit comment on their deletion of the definition of
                ``navigable waters'' at 40 CFR 120.2 and adding it instead with the
                ``purpose and scope'' at 40 CFR 120.1.
                VI. Summary of Supporting Analyses
                 This section provides an overview of the supporting analyses for
                the proposed rule. Additional detail on these analyses is contained in
                and described more fully in the Economic Analysis for the Proposed Rule
                and the Technical Support Document for the Proposed Rule. Copies of
                these documents are available in the docket for this proposed action.
                 This proposed rule establishing the definition of ``waters of the
                United States'' by itself imposes no costs or benefits. Potential costs
                and benefits would only be incurred as a result of actions taken under
                existing Clean Water Act programs (i.e., sections 303, 311, 401, 402,
                and 404) that would not otherwise be modified by this proposed rule.
                Entities currently are, and would continue to be, regulated under these
                programs that protect ``waters of the United States'' from pollution
                and destruction. Each of these programs may subsequently impose costs
                as a result of implementation of their specific regulations.
                 While the rule imposes no costs and generates no benefits under the
                primary baseline, the agencies nonetheless analyzed its benefits and
                costs relative to a secondary baseline and have prepared an
                illustrative economic analysis to provide the public with information
                on the potential benefits and costs associated with various Clean Water
                Act programs that could result under a state of the world without the
                proposed rule that would have the NWPR still in effect. The agencies
                prepared this economic analysis pursuant to the requirements of
                Executive Orders 12866 and 13563 to provide information to the public.
                 Two courts have vacated the NWPR and since then, the agencies have
                been implementing the pre-2015 regulatory regime, which is very similar
                to the proposed rule. While the NWPR has been vacated, the agencies
                have chosen to provide additional information to the public and have
                considered two baselines in the Economic Analysis for the Proposed
                Rule: A primary baseline of the pre-2015 regulatory regime, and a
                secondary baseline of the NWPR. Because the agencies are not currently
                implementing the NWPR, the proposed rule would not depart in material
                respects from current practice; as such, the agencies find that the
                proposed rule generally maintains the legal status quo such that there
                would be no appreciable costs or benefits in comparison to the primary
                baseline of the pre-2015 regulatory regime.
                 The agencies use the NWPR as a secondary baseline to provide
                information to the public on the estimated differential effects of the
                proposed rule in comparison to the NWPR. The agencies estimated that
                the NWPR would result in an increase in non-jurisdictional findings in
                jurisdictional determinations compared to prior regulations and
                practice, and that compared to the NWPR, the proposed rule would define
                more waters as within the scope of the Clean Water Act.
                 Under the primary baseline, there are no costs or benefits as the
                regulatory scope between the presently implemented pre-2015 regulatory
                regime is approximately the same as the proposed rule. Comparatively,
                under the secondary NWPR baseline, quantified benefits for the 404
                program are estimated to be between $376 and $590 million annually,
                while costs are estimated to be between $109 and $276 million annually.
                The analysis of estimated costs and benefits of the proposed rule is
                contained in the Economic Analysis for the Proposed Rule and is
                available in the docket for this action.
                 The agencies recognize that the burdens of environmental pollution
                and climate change often fall disproportionately on population groups
                of concern (e.g., minority, low-income, and indigenous populations as
                specified in Executive Order 12898) and are quantifying impacts to
                these groups in the Economic Analysis for the Proposed Rule. Compared
                to the average population, these groups are more likely to experience
                water-related environmental and social stressors like contaminated
                drinking water, limited access to clean water, and inadequate water
                infrastructure--all of which increase their likelihood of being exposed
                to pollutants. In addition to external stressors, behavioral and
                cultural characteristics of these groups, like engaging in subsistence
                fishing and consuming higher rates of fish from polluted waters,
                increases their vulnerability to pollution. Taken together, these
                environmental, social, and behavioral factors often increase these
                groups' risk of experiencing negative health outcomes because of their
                exposure to environmental contaminants.
                 Climate change will exacerbate the existing risks faced by
                population groups of concern as identified by Executive Order 12898, in
                addition to giving rise to new risks and challenges, and such impacts
                are generally greater for disadvantaged communities. In particular,
                risks like sea level rise, flooding, and drought can all have
                disproportionate effects on these communities. Because of existing
                environmental and social stressors and their reliance on natural
                resources that may be negatively impacted by climate change (e.g., fish
                and other aquatic life that provide income or food), these communities
                may be less able to mitigate and adapt to the effects of climate
                change.
                 The NWPR decreased the scope of Clean Water Act jurisdiction across
                the country, including in geographic regions where regulation of waters
                beyond those covered by the Act is not authorized under current state
                or tribal law (see section V.B.3 of this preamble). Absent regulations
                governing discharges of pollutants into previously jurisdictional
                waters, communities composed of groups of concern where these waters
                are located may experience increased water pollution and impacts from
                associated increases in health risk. Further, the NWPR categorically
                excluded ephemeral streams from jurisdiction, which disproportionately
                impacts tribes and communities of concern in the arid West. Tribes may
                lack the authority and often the resources to regulate waters within
                their boundaries, and may also be affected by pollution from adjacent
                jurisdictions. Therefore, the change in jurisdiction under the NWPR may
                have disproportionately exposed tribes to increased pollution and
                health risks. In this proposed rule the agencies affirm their
                commitment to assessing the impacts of a revised definition of ``waters
                of the United States'' on population groups of concern.
                 For the proposed rule, consistent with Executive Order 12898 and
                Executive Order 14008 on ``Tackling the Climate Crisis at Home and
                Abroad'' (86 FR 7619; January 27, 2021), the agencies examined whether
                the change in benefits from the reinstatement of the pre-2015 practice
                may be differentially distributed among population groups of concern in
                the affected areas when compared to the secondary baseline of
                [[Page 69447]]
                the NWPR. In determining the potential for concerns in affected areas,
                the agencies considered the following factors in this analysis:
                Population characteristics, proximity to effects of the proposed rule,
                and selected indicators of vulnerability to environmental risk. The
                results of the agencies' analysis are presented in the Economic
                Analysis for the Proposed Rule. The change between the pre-2015
                regulatory regime and NWPR in the number of impacted waters was
                approximated using Corps AJD and permit data. The analysis showed that
                for most of the HUC 12 wetlands and affected waters impacted by the
                proposed rule, there was no evidence of potential environmental justice
                concerns warranting further analysis; for a select set of HUC 12
                wetlands and impacted waters, potential environmental justice concerns
                may exist, and additional analyses may be warranted. Additionally,
                analyses assessing the potential for impacts on tribes found an overlap
                in several states between tribal land and HUC 12 watersheds with
                relatively large wetland and affected waters changes, warranting
                further analysis. In the final rule, the agencies plan to expand upon
                the environmental justice analysis by including additional indicators
                of vulnerability to environmental risk in screening for potential
                environmental justice concerns and by adding illustrative case studies
                to evaluate localized impacts for areas where the need for additional
                analyses was identified.
                 The Technical Support Document provides additional legal,
                scientific, and technical discussion for issues raised in this proposed
                rule. Appendix A of the Technical Support Document contains a glossary
                of terms used in the document. Appendix B of the Technical Support
                Document contains the references cited in the document. Appendix C of
                the Technical Support Document is a list of citations that have been
                published since the 2015 Science Report and that contain findings
                relevant to the report's conclusions. Appendix D is the legal
                definition of ``traditional navigable waters'' (Appendix D from the
                U.S. Army Corps of Engineers Jurisdictional Determination Form
                Instructional Guidebook).
                VII. Statutory and Executive Order Reviews
                 Additional information about these statutes and Executive Orders
                can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.
                A. Executive Order 12866: Regulatory Planning and Review; Executive
                Order 13563: Improving Regulation and Regulatory Review
                 This action is a significant regulatory action that was submitted
                to the Office of Management and Budget (OMB) for review. Any changes
                made in response to OMB recommendations have been documented in the
                docket for this action. The agencies prepared an economic analysis of
                the potential costs and benefits associated with this action. This
                analysis, the Economic Analysis for the Proposed ``Revised Definition
                of `Waters of the United States' '' Rule, is available in the docket
                for this action and briefly summarized in section VI of this preamble.
                B. Paperwork Reduction Act (PRA)
                 This action does not impose an information collection burden under
                the PRA because it does not contain any information collection
                activities. However, this action may change terms and concepts used by
                EPA and Army to implement certain programs. The agencies thus may need
                to revise some of their collections of information to be consistent
                with this action.
                C. Regulatory Flexibility Act (RFA)
                 The agencies certify that this proposed rule will not have a
                significant economic impact on a substantial number of small entities
                under the RFA. This rule would codify a regulatory regime generally
                comparable to the one currently being implemented nationwide due to the
                vacatur of the 2020 definition of ``waters of the United States.'' On
                this basis alone, the proposed rule would not impose any requirements
                on small entities. Additionally, the agencies note that the proposed
                rule does not ``subject'' any entities of any size to any specific
                regulatory burden. It is designed to clarify the statutory term
                ``navigable waters,'' defined as ``waters of the United States,'' which
                defines the scope of Clean Water Act jurisdiction 33 U.S.C. 1362(7).
                The scope of Clean Water Act jurisdiction is informed by the text,
                structure and history of the Clean Water Act and Supreme Court case
                law, including the geographical and hydrological factors identified in
                Rapanos v. United States, 547 U.S. 715 (2006). None of these factors
                are readily informed by the RFA. See, e.g., Cement Kiln Recycling Coal.
                v. EPA, 255 F.3d 869 (D.C. Cir. 2001) (``[T]o require an agency to
                assess the impact on all of the nation's small businesses possibly
                affected by a rule would be to convert every rulemaking process into a
                massive exercise in economic modeling, an approach we have already
                rejected.''); Michigan v. EPA, 213 F.3d 663, 688-89 (D.C. Cir. 2000)
                (holding that the RFA imposes ``no obligation to conduct a small entity
                impact analysis of effects'' on entities which it regulates only
                ``indirectly''); Am. Trucking Ass'n v. EPA, 175 F.3d 1027, 1045 (D.C.
                Cir. 1999) (``[A]n agency may justify its certification under the RFA
                upon the ``factual basis'' that the rule does not directly regulate any
                small entities.''); Mid-Tex Elec. Co-op, Inc. v. FERC, 773 F.2d 327,
                343 (D.C. Cir. 1985) (``Congress did not intend to require that every
                agency consider every indirect effect that any regulation might have on
                small businesses in any stratum of the national economy.'').
                 Nevertheless, the agencies recognize that the scope of the term
                ``waters of the United States'' is of great national interest,
                including within the small business community. In light of this
                interest, the agencies sought early input from representatives of small
                entities while formulating a proposed definition of this term,
                including holding a public meeting dedicated to hearing feedback from
                small entities on August 25, 2021 (see https://www.epa.gov/wotus/2021-waters-united-states-public-meeting-materials). A variety of small
                entities such as farmers and ranchers, environmental and conservation
                non-profits, as well as building, consulting, and brewing businesses
                provided their input on both the policies under discussion in the
                proposed rulemaking and their interest in additional outreach and
                engagement with small entities, including their desire for a SBREFA
                panel. The agencies have addressed this feedback in the preamble
                relating to these topics and in the discussion above.
                D. Unfunded Mandates Reform Act (UMRA)
                 This action does not contain any unfunded mandate as described in
                UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
                small governments. The proposed definition of ``waters of the United
                States'' applies broadly to Clean Water Act programs. The action
                imposes no enforceable duty on any state, local, or tribal governments,
                or the private sector.
                E. Executive Order 13132: Federalism
                 Under the technical requirements of Executive Order 13132 (64 FR
                43255, August 10, 1999), the agencies have determined that this
                proposed rule may have federalism implications but believe that the
                requirements of the Executive Order will be satisfied, in any event.
                [[Page 69448]]
                 The agencies believe that a revised definition of ``waters of the
                United States'' may be of significant interest to state and local
                governments. Consistent with the agencies' policies to promote
                communications between the Federal government and state and local
                governments, EPA and the Army consulted with representatives of state
                and local governments early in the process of developing the proposed
                rule to permit them to have meaningful and timely input into its
                development.
                 Consulting with state and local government officials, or their
                representative national organizations, is an important step in the
                process prior to proposing regulations that may have federalism
                implications under the terms of Executive Order 13132. The agencies
                engaged state and local governments over a 60-day federalism
                consultation period during development of this proposed rule, beginning
                with the initial federalism consultation meeting on August 5, 2021, and
                concluding on October 4, 2021. Twenty intergovernmental organizations,
                including eight of the ten organizations identified in EPA's 2008
                Executive Order 13132 Guidance, attended the initial Federalism
                consultation meeting, as well as 12 associations representing state and
                local governments. Organizations in attendance included the following:
                National Governors Association, National Conference of State
                Legislatures, United States Conference of Mayors, National League of
                Cities, National Association of Counties, National Association of Towns
                and Townships, County Executives of America, Environmental Council of
                the States, Association of State Wetland Managers, Association of State
                Drinking Water Administrators, National Association of State
                Departments of Agriculture, Western States Water Council, National
                Association of Clean Water Agencies, National Rural Water Association,
                National Association of Attorneys General, National Water Resources
                Association, National Municipal Stormwater Alliance, Western Governors'
                Association, American Water Works Association, and Association of
                Metropolitan Water Agencies. All letters received by the agencies
                during this consultation may be found in the docket (Docket ID No. EPA-
                HQ-OW-2021-0602) for this proposed rule.
                 These meetings and the letters provided by representatives provide
                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 draft
                report is available in the docket (Docket ID. No. EPA-HQ-OW-2021-0602)
                for this proposed rule.
                F. Executive Order 13175: Consultation and Coordination With Indian
                Tribal Governments
                 This action may have tribal implications. However, it will neither
                impose substantial direct compliance costs on federally recognized
                tribal governments, nor preempt tribal law.
                 EPA and the Army consulted with tribal officials under the EPA
                Policy on Consultation and Coordination with Indian Tribes and the
                Department of the Army American Indian and Alaska Native Policy early
                in the process of developing this regulation to permit them to have
                meaningful and timely input into its development.
                 The agencies initiated a tribal consultation and coordination
                process before proposing this rule by sending a ``Notification of
                Consultation and Coordination'' letter on July 30, 2021, to all 574
                tribes federally recognized at that time. The letter invited tribal
                leaders and designated consultation representatives to participate in
                the tribal consultation and coordination process. The agencies engaged
                tribes over a 66-day tribal consultation period during development of
                this proposed rule, including via two webinars on August 19, 2021, and
                August 24, 2021, in which the agencies answered questions directly from
                tribal representatives and heard their initial feedback on the
                agencies' rulemaking effort. The agencies met with two tribes at a
                staff-level and with two tribes at a leader-to-leader level. Additional
                consultations may be requested and scheduled after the rule is
                proposed. All letters received by the agencies during this consultation
                may be found in the docket (Docket ID. No. EPA-HQ-OW-2021-0602) for
                this proposed rule. The agencies have prepared a report summarizing the
                consultation and further engagement with tribal nations. This report
                (Docket ID. No. EPA-HQ-OW-2021-0602) is available in the docket for
                this proposed rule.
                G. Executive Order 13045: Protection of Children From Environmental
                Health Risks and Safety Risks
                 EPA interprets Executive Order 13045 as applying only to those
                regulatory actions that concern environmental health or safety risks
                that EPA has reason to believe may disproportionately affect children,
                per the definition of ``covered regulatory action'' in section 2-202 of
                the Executive Order. This action is not subject to Executive Order
                13045 because it does not concern an environmental health risk or
                safety risk.
                H. Executive Order 13211: Actions Concerning Regulations That
                Significantly Affect Energy Supply, Distribution, or Use
                 This action is not a ``significant energy action'' because it is
                not likely to have a significant adverse effect on the supply,
                distribution, or use of energy.
                I. National Technology Transfer and Advancement Act
                 This rulemaking does not involve technical standards.
                J. Executive Order 12898: Federal Actions To Address Environmental
                Justice in Minority Populations and Low-Income Populations
                 EPA and Army believe that this action does not have
                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 (59 FR 7629,
                February 16, 1994).
                 The documentation for this decision is contained in in the Economic
                Analysis for the Proposed Rule, which can be found in the docket for
                this action.
                List of Subjects
                33 CFR Part 328
                 Administrative practice and procedure, Environmental protection,
                Navigation (water), Water pollution control, Waterways.
                40 CFR Part 120
                 Environmental protection, Water pollution control, Waterways.
                Jaime A. Pinkham,
                Acting Assistant Secretary of the Army (Civil Works), Department of the
                Army.
                Michael S. Regan,
                Administrator, Environmental Protection Agency.
                Title 33--Navigation and Navigable Waters
                 For the reasons set out in the preamble, title 33, chapter II of
                the Code of Federal Regulations is proposed to be amended as follows:
                PART 328--DEFINITION OF WATERS OF THE UNITED STATES
                0
                1. The authority citation for part 328 continues to read as follows:
                 Authority: 33 U.S.C. 1251 et seq.
                [[Page 69449]]
                0
                2. Revise Sec. 328.3 to read as follows:
                Sec. 328.3 Definitions.
                 For the purpose of this regulation these terms are defined as
                follows:
                 (a) Waters of the United States means:
                 (1) All waters which are currently used, or were used in the past,
                or may be susceptible to use in interstate or foreign commerce,
                including all waters which are subject to the ebb and flow of the tide;
                 (2) All interstate waters including interstate wetlands;
                 (3) All other waters such as intrastate lakes, rivers, streams
                (including intermittent streams), mudflats, sandflats, wetlands,
                sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds:
                 (i) That are relatively permanent, standing or continuously flowing
                bodies of water with a continuous surface connection to the waters
                identified in paragraph (a)(1), (a)(2), (a)(5)(i), or (a)(6) of this
                section; or
                 (ii) That either alone or in combination with similarly situated
                waters in the region, significantly affect the chemical, physical, or
                biological integrity of waters identified in paragraph (a)(1), (2), or
                (6) of this section;
                 (4) All impoundments of waters otherwise defined as waters of the
                United States under the definition, other than impoundments of waters
                identified under paragraph (a)(3) of this section;
                 (5) Tributaries of waters identified in paragraph (a)(1), (2), (4),
                or (6) of this section:
                 (i) That are relatively permanent, standing or continuously flowing
                bodies of water; or
                 (ii) That either alone or in combination with similarly situated
                waters in the region, significantly affect the chemical, physical, or
                biological integrity of waters identified in paragraph (a)(1), (2), or
                (6) of this section;
                 (6) The territorial seas;
                 (7) Wetlands adjacent to the following waters (other than waters
                that are themselves wetlands):
                 (i) Waters identified in paragraph (a)(1), (2), or (6) of this
                section; or
                 (ii) Relatively permanent, standing or continuously flowing bodies
                of water identified in paragraph (a)(4) or (a)(5)(i) of this section
                and with a continuous surface connection to such waters; or
                 (iii) Waters identified in paragraph (a)(4) or (a)(5)(ii) of this
                section when the wetlands either alone or in combination with similarly
                situated waters in the region, significantly affect the chemical,
                physical, or biological integrity of waters identified in paragraph
                (a)(1), (2), or (6) of this section;
                 (8) Waste treatment systems, including treatment ponds or lagoons,
                designed to meet the requirements of the Clean Water Act are not waters
                of the United States; and
                 (9) Waters of the United States do not include prior converted
                cropland. Notwithstanding the determination of an area's status as
                prior converted cropland by any other Federal agency, for the purposes
                of the Clean Water Act, the final authority regarding Clean Water Act
                jurisdiction remains with EPA.
                 (b) Wetlands means those areas that are inundated or saturated by
                surface or ground water at a frequency and duration sufficient to
                support, and that under normal circumstances do support, a prevalence
                of vegetation typically adapted for life in saturated soil conditions.
                Wetlands generally include swamps, marshes, bogs, and similar areas.
                 (c) Adjacent means bordering, contiguous, or neighboring. Wetlands
                separated from other waters of the United States by man-made dikes or
                barriers, natural river berms, beach dunes and the like are ``adjacent
                wetlands.''
                 (d) 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.
                 (e) Ordinary high water mark means that line on the shore
                established by the fluctuations of water and indicated by physical
                characteristics such as clear, natural line impressed on the bank,
                shelving, changes in the character of soil, destruction of terrestrial
                vegetation, the presence of litter and debris, or other appropriate
                means that consider the characteristics of the surrounding areas.
                 (f) Tidal waters means those waters that rise and fall in a
                predictable and measurable rhythm or cycle due to the gravitational
                pulls of the moon and sun. Tidal waters end where the rise and fall of
                the water surface can no longer be practically measured in a
                predictable rhythm due to masking by hydrologic, wind, or other
                effects.
                 (g) Significantly affect means more than speculative or
                insubstantial effects on the chemical, physical, or biological
                integrity of waters identified in paragraph (a)(1), (2), or (6) of this
                section. When assessing whether the effect that the functions waters
                have on waters identified in paragraph (a)(1), (2), or (6) of this
                section is more than speculative or insubstantial, the agencies will
                consider:
                 (1) The distance from a water of the United States;
                 (2) The distance from a water identified in paragraph (a)(1), (2),
                or (6) of this section;
                 (3) Hydrologic factors, including shallow subsurface flow;
                 (4) The size, density, and/or number of waters that have been
                determined to be similarly situated; and
                 (5) Climatological variables such as temperature, rainfall, and
                snowpack.
                Title 40--Protection of Environment
                 For reasons set out in the preamble, title 40, chapter I of the
                Code of Federal Regulations is proposed to be amended as follows:
                PART 120--DEFINITION OF WATERS OF THE UNITED STATES
                0
                3. The authority citation for part 120 continues to read as follows:
                 Authority: 33 U.S.C. 1251 et seq.
                0
                4. Revise Sec. 120.1 to read as follows:
                Sec. 120.1 Purpose and scope.
                 This part contains the definition of ``waters of the United
                States'' for purposes of the Clean Water Act, 33 U.S.C. 1251 et seq.
                and its implementing regulations. EPA regulations implementing the
                Clean Water Act use the term ``navigable waters,'' which is defined at
                section 502(7) of the Clean Water Act as ``the waters of the United
                States, including the territorial seas,'' or the term ``waters of the
                United States.'' In light of the statutory definition, the definition
                in this section establishes the scope of the terms ``waters of the
                United States'' and ``navigable waters'' in EPA's regulations.
                0
                5. Revise Sec. 120.2 to read as follows:
                Sec. 120.2 Definitions.
                 For the purposes of this part, the following terms shall have the
                meanings indicated:
                 (a) Waters of the United States means:
                 (1) All waters which are currently used, or were used in the past,
                or may
                [[Page 69450]]
                be susceptible to use in interstate or foreign commerce, including all
                waters which are subject to the ebb and flow of the tide;
                 (2) All interstate waters including interstate wetlands;
                 (3) All other waters such as intrastate lakes, rivers, streams
                (including intermittent streams), mudflats, sandflats, wetlands,
                sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds:
                 (i) That are relatively permanent, standing or continuously flowing
                bodies of water with a continuous surface connection to the waters
                identified in paragraph (a)(1), (a)(2), (a)(5)(i), or (a)(6) of this
                section; or
                 (ii) That either alone or in combination with similarly situated
                waters in the region, significantly affect the chemical, physical, or
                biological integrity of waters identified in paragraph (a)(1), (2), or
                (6) of this section;
                 (4) All impoundments of waters otherwise defined as waters of the
                United States under the definition, other than impoundments of waters
                identified under paragraph (a)(3) of this section;
                 (5) Tributaries of waters identified in paragraph (a)(1), (2), (4),
                or (6) of this section:
                 (i) That are relatively permanent, standing or continuously flowing
                bodies of water; or
                 (ii) That either alone or in combination with similarly situated
                waters in the region, significantly affect the chemical, physical, or
                biological integrity of waters identified in paragraph (a)(1), (2), or
                (6) of this section;
                 (6) The territorial seas;
                 (7) Wetlands adjacent to the following waters (other than waters
                that are themselves wetlands):
                 (i) Waters identified in paragraph (a)(1), (2), or (6) of this
                section; or
                 (ii) Relatively permanent, standing, or continuously flowing bodies
                of water identified in paragraph (a)(4) or (a)(5)(i) of this section
                and with a continuous surface connection to such waters; or
                 (iii) Waters identified in paragraph (a)(4) or (a)(5)(ii) of this
                section when the wetlands either alone or in combination with similarly
                situated waters in the region, significantly affect the chemical,
                physical, or biological integrity of waters identified in paragraph
                (a)(1), (2), or (6) of this section;
                 (8) Waste treatment systems, including treatment ponds or lagoons,
                designed to meet the requirements of the Clean Water Act are not waters
                of the United States; and
                 (9) Waters of the United States do not include prior converted
                cropland. Notwithstanding the determination of an area's status as
                prior converted cropland by any other Federal agency, for the purposes
                of the Clean Water Act, the final authority regarding Clean Water Act
                jurisdiction remains with EPA.
                 (b) Wetlands means those areas that are inundated or saturated by
                surface or ground water at a frequency and duration sufficient to
                support, and that under normal circumstances do support, a prevalence
                of vegetation typically adapted for life in saturated soil conditions.
                Wetlands generally include swamps, marshes, bogs, and similar areas.
                 (c) Adjacent means bordering, contiguous, or neighboring. Wetlands
                separated from other waters of the United States by man-made dikes or
                barriers, natural river berms, beach dunes and the like are ``adjacent
                wetlands.''
                 (d) 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.
                 (e) Ordinary high water mark means that line on the shore
                established by the fluctuations of water and indicated by physical
                characteristics such as clear, natural line impressed on the bank,
                shelving, changes in the character of soil, destruction of terrestrial
                vegetation, the presence of litter and debris, or other appropriate
                means that consider the characteristics of the surrounding areas.
                 (f) Tidal waters means those waters that rise and fall in a
                predictable and measurable rhythm or cycle due to the gravitational
                pulls of the moon and sun. Tidal waters end where the rise and fall of
                the water surface can no longer be practically measured in a
                predictable rhythm due to masking by hydrologic, wind, or other
                effects.
                 (g) Significantly affect means more than speculative or
                insubstantial effects on the chemical, physical, or biological
                integrity of waters identified in paragraph (a)(1), (2), or (6) of this
                section. When assessing whether the effect that the functions waters
                have on waters identified in paragraph (a)(1), (2), or (6) of this
                section is more than speculative or insubstantial, the agencies will
                consider:
                 (1) The distance from a water of the United States;
                 (2) The distance from a water identified in paragraph (a)(1), (2),
                or (6) of this section;
                 (3) Hydrologic factors, including shallow subsurface flow;
                 (4) The size, density, and/or number of waters that have been
                determined to be similarly situated; and
                 (5) Climatological variables such as temperature, rainfall, and
                snowpack.
                [FR Doc. 2021-25601 Filed 12-6-21; 8:45 am]
                BILLING CODE 6560-50-P
                

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